WO2007021498A1 - Selective vpac2 receptor peptide agonists - Google Patents

Selective vpac2 receptor peptide agonists Download PDF

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Publication number
WO2007021498A1
WO2007021498A1 PCT/US2006/029440 US2006029440W WO2007021498A1 WO 2007021498 A1 WO2007021498 A1 WO 2007021498A1 US 2006029440 W US2006029440 W US 2006029440W WO 2007021498 A1 WO2007021498 A1 WO 2007021498A1
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Prior art keywords
xaa
seq
ome
hsdavfteqy
absent
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PCT/US2006/029440
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French (fr)
Inventor
Jorge Alsina-Fernandez
Bengt Krister Bokvist
Lianshan Zhang
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Eli Lilly And Company
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Publication date
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Priority to CA002618740A priority Critical patent/CA2618740A1/en
Priority to US11/997,499 priority patent/US20080194482A1/en
Priority to EP06788811A priority patent/EP1915393A1/en
Publication of WO2007021498A1 publication Critical patent/WO2007021498A1/en

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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K14/00—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof
    • C07K14/435—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans
    • C07K14/575—Hormones
    • C07K14/57563—Vasoactive intestinal peptide [VIP]; Related peptides
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P3/00—Drugs for disorders of the metabolism
    • A61P3/08—Drugs for disorders of the metabolism for glucose homeostasis
    • A61P3/10—Drugs for disorders of the metabolism for glucose homeostasis for hyperglycaemia, e.g. antidiabetics
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K38/00—Medicinal preparations containing peptides

Definitions

  • the present invention relates to selective VPAC2 receptor peptide agonists.
  • Type 2 diabetes or non-insulin dependent diabetes mellitus (NIDDM)
  • NTDDM non-insulin dependent diabetes mellitus
  • patients With impaired ⁇ -cell function resulting in insufficient insulin production and/or decreased insulin sensitivity.
  • excess glucose accumulates in the blood, resulting in hyperglycemia. Over time, more serious complications may arise including renal dysfunction, cardiovascular problems, visual loss, lower limb ulceration, neuropathy, and ischemia.
  • Treatments for NIDDM include improving diet, exercise, and weight control as well as using a variety of oral medications. Individuals with NTDDM can initially control their blood glucose levels by taking such oral medications.
  • NTDDM patients do not slow the progressive loss of ⁇ -cell function that occurs in NTDDM patients and, thus, are not sufficient to control blood glucose levels in the later stages of the disease.
  • treatment with currently available medications exposes NIDDM patients to potential side effects such as hypoglycemia, gastrointestinal problems, fluid retention, oedema, and/or weight gain.
  • PACAP Pituitary adenylate cyclase-activating peptide
  • VIP vasoactive intestinal peptide
  • PACAP and VIP work through three G-protein-coupled receptors that exert their action through the cAMP-mediated and other Ca 2+ -mediated signal transduction pathways. These receptors are known as the PACAP-preferring type 1 (PACl) receptor (Isobe, et al, Regul. Pept., 110:213-217 (2003); Ogi, et al., Biochem. Biophys. Res.
  • PACl PACAP-preferring type 1
  • VPACl and VPAC2 the two VIP-shared type 2 receptors
  • VPACl and VPAC2 the two VIP-shared type 2 receptors
  • PACAP PACAP analogues
  • VDMnduced watery diarrhoea in rats is mediated by only one of the VPAC receptors, VPACl (Ito et al , Peptides, 22: 1139-1151 (2001); Tsutsumi et al, Diabetes, 51:1453-1460 (2002)).
  • VPACl and PACl receptors are expressed on ⁇ -cells and hepatocytes and, thus, are most likely involved in the effects on hepatic glucose output.
  • Exendin-4 is found in the salivary excretions from the GiIa Monster, Heloderma Suspectum, (Eng et al, J.Biol.Chem., 267(11):7402-7405 (1992)). It is a 39 amino acid peptide, which has glucose dependent insulin secretagogue activity.
  • VPAC2 receptor vasoactive intestinal peptide
  • PACAP pituitary adenylate cyclase-activating polypeptide
  • VPAC2 receptor peptide agonists See, for example, Xia et al, J Pharmacol Exp Ther., 281:629-633 (1997); Tsutsumi et al, Diabetes, 51:1453-1460 (2002); WO 01/23420; and WO 2004/06839.
  • Many of the VPAC2 receptor peptide agonists reported to date have, however, less than desirable potency, selectivity, and/or stability profiles, which could impede their clinical viability.
  • many of these peptides are not suitable for commercial candidates as a result of stability issues associated with the polypeptides in formulation, as well as issues with the short half-life of these polypeptides in vivo.
  • the present invention seeks to provide improved compounds that are selective for the VPAC2 receptor and which induce insulin secretion from the pancreas only in the presence of high blood glucose levels.
  • the compounds of the present invention are peptides, which are believed to also improve beta cell function. These peptides can have the physiological effect of inducing insulin secretion without GI side effects or a corresponding increase in hepatic glucose output and also generally have enhanced selectivity, potency, and/or in vivo stability of the peptide compared to known VPAC2 receptor peptide agonists.
  • VPAC2 receptor peptide agonist comprising a sequence selected from: SEQ JD NO: 17 HSDA VFTEQY(OMe)TRAibRAibQLAAAibOrn Y(OMe)LQSIK
  • SEQ ID NO: 18 HSDAVFTEK(CO(CH 2 ) 2 SH)Y(OMe)TOrnLRAibQVAAAibOrn YLQSIOrnOrn;
  • SlOrnOrn SEQ ID NO: 22 HSD AVFTEQ Y(OMe)TOrnLRAibQVCAAibOrnYLQSIOrnOrn;
  • SEQ ID NO: 24 HSD AVFTEQY(OMe)TOrnLRAibQLAAAibOrn YLQSIOrnOrn;
  • SEQ ID NO: 26 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQAibIOrnOrn; SEQ ID NO: 27 HSDAVFTEQY(OMe)TOmLRAibQVAAbuAibOrnYLQAibIOrnOrn;
  • SEQ ID NO: 28 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQAibIOrnOrn;
  • SEQ ID NO: 29 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQAibIOrnOrn; SEQ ID NO: 30 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYAibQSIOrnOrn; SEQ ID NO: 31 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmYLQSIOmOrn; SEQ ID NO: 32 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYAibQAibIOm
  • SEQ ID NO: 38 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibK(W) YLQSIOmOm; SEQ ID NO: 39 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibCYLQSIOrnOrn; SEQ ID NO: 40 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrnOm; SEQ ID NO: 41 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLQSK(W)OmOm; SEQ ID NO: 42 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQAibIOmC
  • SEQ ID NO: 110 HSDAVFTEQY(OMe)TOmLRAibQK(W)AAbuAibOmYLQ AiblOrnOrn;
  • SEQ ID NO: 160 HSDAVFTDSYTOmLRAibQVAAAibKYLQSIOrnNOrn; SEQ ID NO: 161 HSD AVFTDN YThRLR AibQV A A AibKYLQS IKNKRY;
  • SEQ ID NO: 170 HSEAVFTEQY(OMe)TOrnLRAibQLAAAibOmYLQSIOrnOm; SEQ ID NO: 171 HSDAVFTDQY(OMe)TOrnLRAibQLAAAibOmYLQSIOmOrn;
  • SEQ ID NO: 175 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOmOm; SEQ ID NO: 176 HSDAVFTDNYTRAibRAibQVAAAibKYLQSIKAibK;
  • SEQ ID NO: 180 HSEAVFTEQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK; SEQ ID NO: 181 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLCSIOmOrn;
  • a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide sequence and wherein the C-terminal extension comprises an amino acid sequence of the formula: Xaa 1 -Xaa 2 -Xaa 3 -Xaa 4 -Xaa 5 -Xaa 6 -Xaa 7 -Xaa 8 -Xaa 9 -Xaa 10 -Xaa 1 i-Xaa 12
  • Xaa is: GIy, Cys, or absent;
  • Xaa 2 is: GIy, Arg, or absent;
  • Xaa 3 is: Pro, Thr, or absent;
  • Xaa* is: Ser, or absent
  • Xaas is: Ser, or absent; Xaa 6 is: GIy, or absent;
  • Xaa 7 is: Ala, or absent
  • Xaa 8 is: Pro, or absent
  • Xaa 9 is: Pro, or absent
  • Xaa 10 is: Pro, or absent
  • Xaa ⁇ is: Ser, Cys, or absent
  • Xaa 12 is: Cys, or absent; wherein at least five of Xaai to Xaa 12 of the C-terminal extension are present and wherein if Xaa 1; Xaa 2 , Xaa 3 , Xaa 4 , Xaa 5 , Xaa 6 , Xaa 7 , Xaa 8 , Xaa 9 , Xaa 10 , or Xaa ⁇ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
  • At least six of Xaai to Xaa ⁇ of the C-terminal extension of Formula 3 are present. More preferably, at least seven, eight, nine, ten, eleven, or all of Xaa 1 to Xaa 12 of the C-terminal extension are present.
  • the C-terminal extension of the VPAC2 receptor peptide agonist is selected from:
  • the VPAC2 receptor peptide agonist sequence may further comprise a histidine residue at the N-terminus of the peptide.
  • the VPAC2 receptor peptide agonist according to the first aspect of the present invention further comprises a N-terminal modification at the N-terminus of the peptide agonist wherein the N-terminal modification is selected from: (a) addition of D-histidine, isoleucine, methionine, or norleucine; (b) addition of a peptide comprising the sequence Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys- Arg (SEQ ID NO: 91) wherein the Arg is linked to the N-terminus of the peptide agonist;
  • R 1 is a C 1 -C 16 alkyl optionally substituted with one or more substituents independently selected from aryl, Ci-C 6 alkoxy, -NH 2 , -OH, halogen, -SH and -CF 3; a aryl or aryl C 1 -C 4 alkyl optionally substituted with one or more substituents independently selected from C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, Ci-C 6 alkoxy, -NH 2 , -OH, halogen and -CF 3 ; -NR 2 R 3 wherein R 2 and R 3 are independently hydrogen, C 1 -C 6 alkyl, aryl or aryl Ci-C 4 alkyl; -OR 4 wherein R 4 is C 1 -C 16 alkyl optionally substituted with one or more substituents independently selected from aryl, Ci-C 6 alk
  • VPAC2 receptor peptide agonists comprising various combinations of peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199, C-terminal extensions and N-terminal modifications as described herein, may be made based on the above disclosure. It is preferred that the VPAC2 receptor peptide agonist according to the first aspect of the present invention comprises an amino acid sequence selected from:
  • VPAC2 receptor peptide agonist according to the first aspect of the present invention comprises an amino acid sequence selected from:
  • VPAC2 receptor peptide agonist comprising an amino acid sequence of the formula: Xaa! -Xaa 2 -Xaa 3 -Xaa 4 -Xaa 5 -Xaa 6 -Thr-Xaas-Xaa 9 -Xaai o-Thr-Xaai 2 -Xaa 13 - Xaa !
  • Xaa ⁇ is: His, dH, or is absent;
  • Xaa 2 is: dA, Ser, VaI, GIy, Thr, Leu, dS, Pro, or Aib;
  • Xaa 3 is: Asp or GIu;
  • Xaa 4 is: Ala, De, Tyr, Phe, VaI, Thr, Leu, Trp, GIy, dA, Aib, or NMeA;
  • Xaa 5 is: VaI, Leu, Phe, He, Thr, Trp, Tyr, dV, Aib, or NMeV;
  • Xaa 6 is: Phe, lie, Leu, Thr, VaI, Trp, or Tyr;
  • Xaag is: Asp, GIu, Ala, Lys, Leu, Arg, or Tyr;
  • Xaa 9 is: Asn, GIn, Asp, GIu, Ser, Cys, Lys, or K(CO(CH 2 ) 2 SH);
  • Xaa 10 is: Tyr, Trp, Tyr(OMe), Ser, Cys, or Lys;
  • Xaa 12 is: Arg, Lys, GIu, hR, Orn, Lys (isopropyl), Aib, Cit, Ala, Leu, GIn, Phe, Ser, or
  • Xaa 13 is: Leu, Phe, GIu, Ala, Aib, Ser, Cys, Lys, or K(CO(CH 2 ) 2 SH);
  • Xaa 14 is: Arg, Leu, Lys, Ala, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, Cit, Ser, or Cys;
  • Xaa 15 is: Lys, Ala, Arg, GIu, Leu, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, K(Ac), Cit,
  • Xaa 16 is: GIn, Lys, GIu, Ala, hR, Orn, Lys (isopropyl), Cit, Ser, Cys, K(CO(CH 2 ) 2 SH), or
  • Xaa 17 is: VaI, Ala, Leu, lie, Met, NIe, Lys, Aib, Ser, Cys, K(CO(CH 2 ) 2 SH), or K(W);
  • Xaa 18 is: Ala, Ser, Cys, Lys, K(CO(CH 2 ) 2 SH), K(W), Abu, or NIe;
  • Xaa 20 is: Lys, GIn, hR, Arg, Ser, His, Orn, Lys (isopropyl), Ala, Aib, Trp, Thr, Leu, He,
  • Xaa 21 is: Lys, His, Arg, Ala, Phe, Aib, Leu, GIn, Orn, hR, K(Ac), Cit, Ser, Cys, VaI, Tyr,
  • Xaa 22 is: Tyr, Trp, Phe, Thr, Leu, He, VaI, Tyr(OMe), Ala, Aib, Ser, Cys, Lys, K(W), or
  • Xaa 23 is: Leu, Phe, He, Ala, Trp, Thr, VaI, Aib, Ser, Cys, Lys, K(W), or K(CO(CH 2 ) 2 SH);
  • Xaa 24 is: GIn, GIu, Asn, Ser, Cys, Lys, K(CO(CH 2 ) 2 SH), or K(W);
  • Xaa 25 is: Ser, Asp, Phe, He, Leu, Thr, VaI, Trp, GIn, Asn, Tyr, Aib, GIu, Cys, Lys,
  • Xaa 26 is: He, Leu, Thr, VaI, Trp, Tyr, Phe, Aib, Ser, Cys, Lys, K(CO(CH 2 ) 2 SH), or K(W);
  • Xaa 27 is: Lys, hR, Arg, GIn, Ala, Asp, GIu, Phe, GIy, His, He, Met, Asn, Pro, Ser, Thr,
  • Xaa 28 is: Asn, Asp, GIn, Lys, Arg, Aib, Orn, hR, Cit, Pro, dK, Ser, Cys, K(CO(CH 2 ) 2 SH), or K(W);
  • Xaa 29 is: Lys, Ser, Arg, Asn, hR, Ala, Asp, GIu, Phe, GIy, His, He, Leu, Met, Pro, GIn, Thr, VaI, Trp, Tyr, Cys, Orn, Cit, Aib, K(W), K(CO(CH 2 ) 2 SH), or is absent;
  • Xaa 30 is: Arg, Lys, He, Ala, Asp, GIu, Phe, GIy, His, Leu, Met, Asn, Pro, GIn, Ser, Thr,
  • Xaa 3 i is: Tyr, His, Phe, Thr, Cys, Ser, Lys, GIn, K(W), K(CO(CH 2 ) 2 SH), or is absent;
  • Xaa 32 is: Ser, Cys, Lys, or is absent;
  • Xaa 33 is: Trp or is absent;
  • Xaa 34 is: Cys or is absent
  • Xaa 35 is: GIu or is absent
  • Xaa 36 is: Pro or is absent
  • Xaa 37 is: GIy or is absent;
  • Xaa 38 is: Trp or is absent;
  • Xaa 3 g is: Cys or is absent
  • Xaa 40 is: Arg or is absent wherein if Xaa 29 , Xaa 30 , Xaa 31 , Xaa 32 , Xaa 33 , Xaa 34 , Xaa 35 , Xaa 36 , Xaa 37 , Xaa 38 , or Xaa 39 is absent, the next amino acid present downstream is the next amino acid in the peptide agonist sequence, and a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide of Formula 4 and wherein the C-terminal extension comprises an amino acid sequence of the formula:
  • Formula 3 (SEQ ID NO: 3) wherein: Xaai is: GIy, Cys, or absent;
  • Xaa 2 is: GIy, Arg, or absent;
  • Xaa 3 is: Pro, Thr, or absent
  • Xaa 4 is: Ser, or absent
  • Xaa 5 is: Ser, or absent
  • Xaa 6 is: GIy, or absent
  • Xaa 7 is: Ala, or absent
  • Xaa 8 is: Pro, or absent
  • Xaa 9 is: Pro, or absent
  • Xaa 10 is: Pro, or absent
  • Xaa ⁇ is: Ser, Cys, or absent
  • Xaa 12 is: Cys, or absent; wherein at least five of Xaai to Xaa 12 of the C-terminal extension are present and wherein if Xaa l5 Xaa 2 , Xaa 3 , Xaa 4 , Xaa 5 , Xaa 6 , Xaa 7 , Xaa 8 , Xaa 9 , Xaa 10 , or Xaa ⁇ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
  • At least six of Xaai to Xaa 12 of the C-terminal extension of Formula 3 is present. More preferably, seven, eight, nine, ten, eleven, or all of Xaa] to Xaa 12 of the
  • the C-terminal extension of the VPAC2 receptor peptide agonist according to the second aspect of the present invention is selected from:
  • An alternative C-terminal extension according to the second aspect of the present invention may comprise an amino acid sequence of the formula: Xaa 1 -Xaa 2 -Xaa 3 -Xaa 4 -Xaa 5 -Xaa 6 -Xaa 7 -Xaa 8 -Xaa 9 -Xaa 10
  • Xaaj is: Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 2 is: Arg, Ser, hR, Om, His, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 3 is: Thr, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 4 is: Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 5 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CEb) 2 SH), or absent;
  • Xaa 6 is: Pro, Ser, Ala, Arg, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 7 is: Pro, Ser, Ala, Cys, Lys,
  • next amino acid downstream is the next amino acid in the C- terminal extension.
  • the C-terminal amino acid may be amidated.
  • At least one of Xaai to Xaa ⁇ of the C-terminal extension of Formula 13 is present. More preferably, at least two, three, four, five, six, seven, eight, nine or all of Xaai to Xaa 10 of the C-terminal extension are present. More preferably the alternative C-terminal extension of the VPAC2 receptor peptide agonist is selected from:
  • the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 (SEQ DD NO: 4) wherein Xaa 3 is Asp or GIu, Xaa 8 is Asp or GIu, Xaa 9 is Asn or GIn, Xaa 10 is Tyr or Tyr(OMe), Xaa ⁇ is Arg, hR, Lys, or Orn, Xaa 14 is Arg, GIn, Aib, hR, Orn, Cit, Lys, Ala, or Leu, Xaa 15 is Lys, Aib, Orn, or Arg, Xaa 16 is GIn or Lys, Xaa 17 is VaI, Leu, Ala, He, Lys, or NIe, Xaa 20 is Lys, VaI, Leu, Aib, Ala, GIn, or Arg, Xaa 21 is Lys, Aib, Orn, Ala, GIn
  • the VPAC2 receptor peptide according to the second aspect of the present invention comprises a sequence of the Formula 4 (SEQ ID NO: 4) wherein either Xaa 23 or Xaa 25 is Aib. Even more preferably, Xaa 23 and Xaa 25 are both Aib.
  • the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein either Xaa 14 or Xaa 15 is Aib.
  • the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein either Xaa 20 or Xaa 21 is Aib.
  • either Xaa 14 or Xaa ⁇ is Aib and either Xaa 2 o or Xaa 21 is Aib. It is especially preferred that Xaa 15 is Aib and Xaa 2 o is Aib.
  • the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein Xaais is Aib, Xaa 2 o is Aib, and Xaa 12 , Xaa 21 , Xaa 27 and Xaa 28 are all Orn. More preferably, Xaa 15 is Aib, Xaa 20 is Aib, Xaa 12 , Xaa 21 , Xaa 27 and Xaa 28 are all Orn, Xaa 8 is GIu, Xaa 9 is GIn and Xaa 10 is Tyr(OMe).
  • Xaa 15 is Aib
  • Xaa 2 o is Aib
  • Xaa 12 , Xaa 21 , Xaa 27 and Xaa 28 are all Orn
  • Xaag is GIu
  • Xaa 9 is GIn
  • Xaaio is Tyr(OMe)
  • Xaa 23 and/or Xaa 25 is Aib.
  • the VPAC2 receptor peptide agonist according to the second aspect of the present invention further comprises a N-terminal modification at the N-terminus of the peptide agonist wherein the N-terrninal modification is selected from:
  • R 1 is a C 1 -C 16 alkyl optionally substituted with one or more substituents independently selected from aryl, C 1 -C 6 alkoxy, -NH 2 , -OH, halogen, -SH and -CF 3; an aryl optionally substituted with one or more substituents independently selected from C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, -NH 2 , -OH, halogen and -CF 3 ; an aryl C 1 -C 4 alkyl optionally substituted with one or more substituents independently selected from C 1 -C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, C 1 -C 6 alkoxy, -NH 2 , -OH, halogen and -CF 3 ; -NR 2
  • VPAC2 receptor peptide agonists comprising various combinations of peptide sequence according to Formula 4, C-terminal extensions and N-terminal modifications as described herein, may be made based on the above disclosure.
  • a pharmaceutical composition comprising a VPAC2 receptor peptide agonist of the present invention and one or more pharmaceutically acceptable diluents, carriers and excipients.
  • a VPAC2 receptor peptide agonist of the present invention for use as a medicament.
  • a VPAC2 receptor peptide agonist of the present invention for the manufacture of a medicament for the treatment of non-insulin-dependent diabetes.
  • a VPAC2 receptor peptide agonist of the present invention for the manufacture of a medicament for the treatment of insulin-dependent diabetes.
  • the present invention provides a method of treating diabetes in a patient in need thereof comprising administering a VPAC2 receptor peptide agonist of the present invention, wherein the diabetes may be non-insulin dependent diabetes or may be insulin- dependent diabetes.
  • the present invention further provides a pharmaceutical composition containing a VPAC2 receptor peptide agonist of the present invention for treating non-insulin dependent diabetes or insulin-dependent diabetes.
  • a VPAC2 receptor peptide agonist comprising a sequence selected from: SEQ ID NO: 17 HSDAVFTEQY(OMe)TRAibRAibQLAAAibOrn Y(OMe)LQSIK AibOrn; SEQ ID NO: 18 HSDAVFTEK(CO(CH 2 ) 2 SH)Y(OMe)TOraLRAibQVAAAibOrn
  • SEQ ID NO: 33 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQSIOrnOrn; SEQ ID NO: 34 HSDA VFTEQY(OMe)TOmLRK(W)Q VAAAibOrnYLQSIOrnOrn; SEQ ID NO: 35 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLK(W)SIOmOm; SEQ ID NO: 36 HSDAVFTEQY(OMe)TOmLRAibQK(W)AAAibOrnYLQSIOrnOrn; SEQ ID NO: 37 HSDA VFTEQY(OMe)TOrnLRK(CO(CH 2 ) 2 SH)QVAAAibOrn YLQ
  • SEQ ID NO: 38 HSDAVFTEQY(OMe)TOmLRAibQVAAAibK(W) YLQSIOmOm; SEQ ID NO: 39 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibCYLQSIOrnOrn; SEQ ID NO: 40 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 41 HSDA VFTEQY(OMe)TOrnLRAibQVAAAibOrn YLQSK(W)OmOm; SEQ ID NO: 42 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrnC Orn; SEQ ID NO: 43 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibCOrn
  • OrnCOrn SEQ ID NO: 103 HSDAVFTEQY(OMe)TOrnLRAibQCAAbuAibOrnY(OMe)LQAibI
  • SEQ ID NO: 106 HSD A VFTEQY(OMe)TOrnLRAibQCAAbuAibOrn Y(OMe)LQSI OrnOrn;
  • SEQ ID NO: 110 HSD AVFTEQ Y(OMe)TOrnLRAibQK(W)AAbuAibOmYLQ AiblOmOrn;
  • SEQ ID NO: 150 HSDAVFTDNYTOrnLRAibQVAACOmYLQSIOmNOrn;
  • SEQ ID NO: 160 HSDAVFTDSYTOrnLRAibQVAAAibKYLQSIOrnNOrn;
  • SEQ ID NO: 163 HSDAVFTDNY(OMe)TRLRAibQVAAAibKYLQSIKNKRY; SEQ ID NO: 164 HSEAVFTENYTOrnLRAibQVAAAibKYLQSIOmNOrn;
  • SEQ ID NO: 175 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOrnOrn; SEQ ID NO: 176 HSDAVFTDNYTRAibRAibQVAAAibKYLQSIKAibK;
  • SEQ ID NO: 180 HSEAVFTEQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK; SEQ ID NO: 181 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLCSIOrnOrn;
  • the VPAC2 receptor peptide agonist of the above alternative embodiment further comprises a C-terminal extension, wherein the N-terminus of the C- terminal extension is linked to the C-terminus of the peptide sequence and wherein the C- terminal extension comprises an amino acid sequence of the formula: Xaa 1 -Xaa 2 -Xaa 3 -Xaa 4 -Xaa 5 -Xaa 6 -Xaa 7 -Xaa 8 -Xaac r Xaa 1 o-Xaa 11 -Xaa 12 -
  • Xaaj is: GIy, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 2 is: GIy, Arg, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 3 is: Pro, Thr, Ser, Ala, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 4 is: Ser, Pro, His, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 5 is: Ser, Arg, Thr, Trp, Lys, Cys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 6 is: GIy, Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 7 is: Ala, Asp, Arg, GIu, Lys, GIy, Cys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 8 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent
  • Xaa 9
  • the C-terminal extension of formula 1 has no more than three of any one of the following; Cys, Lys, K(W) or K(CO(CH 2 ) 2 SH). It is more preferable that the C-terminal extension has no more than two of any of these residues. If there are two Cys residues in the C-terminal extension, it is preferred that the Cys residues are at the C-terminus. It is even more preferable that the C-terminal extension has no more than one of any of these residues. If there is only one Cys residue in the C-terminal extension, it is preferred that the Cys residue is at the C-terminus.
  • the C-terminal extension of the VPAC2 receptor peptide agonist according to the above alternative embodiment comprises an amino acid sequence of the formula:
  • Xaa is: GIy, Cys, Lys, or absent;
  • Xaa 2 is: GIy, Arg, Cys, Lys, or absent;
  • Xaa 3 is: Pro, Thr, Ser, Ala, Cys, Lys, or absent
  • Xaa 4 is: Ser, Pro, His, Cys, Lys, or absent
  • Xaa 5 is: Ser, Arg, Thr, Trp, Lys, Cys, or absent;
  • Xaa 6 is: GIy, Ser, Cys, Lys, or absent;
  • Xaa 7 is: Ala, Asp, Arg, GIu, Lys, GIy, Cys, or absent;
  • Xaa 8 is: Pro, Ser, Ala, Cys, Lys, or absent
  • Xaag is: Pro, Ser, Ala, Cys, Lys, or absent
  • Xaaio is: Pro, Ser, Ala, Arg, Lys, His, Cys, or absent;
  • Xaa ⁇ is: Ser, Cys, His, Pro, Lys, Arg, or absent;
  • Xaa 12 is: His, Ser, Arg, Lys, Cys, or absent;
  • Xaa 13 is: His, Ser, Arg, Lys, Cys, or absent; provided that if Xaa 1 ; Xaa 2 , Xaa 3 , Xaa 4 , Xaa 5 , Xaa ⁇ , Xaa 7 , Xaag, Xaag, Xaa 10 ,
  • next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
  • the C-terminal extension of the VPAC2 receptor peptide agonist comprises an amino acid sequence of the formula:
  • Xaa ! is: GIy, Cys, or absent;
  • Xaa 2 is: GIy, Arg, or absent;
  • Xaa 3 is: Pro, Thr, or absent;
  • Xaa 4 is: Ser, or absent;
  • Xaa 5 is: Ser, or absent;
  • Xaa 6 is: GIy, or absent;
  • Xaa 7 is: Ala, or absent;
  • Xaag is: Pro, or absent;
  • Xaa 9 is: Pro, or absent;
  • Xaa 10 is: Pro, or absent;
  • Xaa ⁇ is: Ser, Cys, or absent;
  • Xaa 12 is: Cys, or absent; provided that if Xaa l5 Xaa 2 , Xaa 3 , Xaa 4 , Xaa 5 , Xaa 6 , Xaa 7 , Xaa 8 , Xaa 9 ,
  • At least one of Xaai to Xaa 12 of the C-terminal extension of Formula 3 is present. More preferably, at least two, three, four, five, six, seven, eight, nine, ten, eleven, or all of Xaai to Xaa 12 of the C-terminal extension are present.
  • An alternative C-terminal extension may comprise an amino acid sequence of the formula:
  • Formula 13 (SEQ ID NO: 13) wherein: Xaai is: Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 2 is: Arg, Ser, hR, Orn, His, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 3 is: Thr, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 4 is: Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 5 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 6 is: Pro, Ser, Ala, Arg, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 7 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 8 is: Lys, K(W), Pro, Cys, K(CO(CH 2 ) 2 SH), or absent;
  • Xaa 9 is: K(E-C 16 ), Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent; and
  • Xaa 10 is: Ser, Cys, Lys, K(W), K(CO(CH 2 ) 2 SH), or absent.
  • next amino acid downstream is the next amino acid in the C- terminal extension.
  • the C-terminal amino acid may be amidated.
  • At least one of Xaa] to Xaa 10 of the C-terminal extension of Formula 13 is present. More preferably, at least two, three, four, five, six, seven, eight, nine or all of Xaai to Xaaio of the C-terminal extension are present.
  • the alternative C-terminal extension of Formula 13 is selected from:
  • VPAC2 receptor peptide agonists include:
  • VPAC2 receptor peptide agonists of the present invention have the advantage that they have enhanced selectivity, potency and/or stability over known VPAC2 receptor peptide agonists.
  • the addition of the C-terminal sequence of Exendin-4 as the c-capping sequence surprisingly increased the VPAC2 receptor selectivity as well as increasing proteolytic stability.
  • VPAC2 is used to refer to and in conjunction with the particular receptor (Lutz, et al., FEBS Lett., 458: 197-203 (1999); Adamou, et al., Biochem. Biophys. Res. Commun., 209: 385-392 (1995)) that the agonists of the present invention activate. This term also is used to refer to and in conjunction with the agonists of the present invention.
  • a "selective VPAC2 receptor peptide agonist" or a "VPAC2 receptor peptide agonist” of the present invention is a peptide that selectively activates the VPAC2 receptor to induce insulin secretion.
  • the sequence for a selective VPAC2 receptor peptide agonist of the present invention has twenty-eight to forty naturally occurring and/or non-naturally occurring amino acids and may or may not additionally comprise a C-terminal extension.
  • the "C-terminal extension" of the present invention comprises a sequence having from one to thirteen naturally occurring or non-naturally occurring amino acids linked to the C-terminus of the sequence at the N-terminus of the C-terminal extension via a peptide bond.
  • the term "linked to” with reference to the term C-terminal extension includes the addition or attachment of amino acids or chemical groups directly to the C-terminus of the peptide sequence.
  • the selective VPAC2 receptor peptide agonist may also have an N- terminal modification.
  • N-terminal modification as used herein includes the addition or attachment of amino acids or chemical groups directly to the N-terminus of a peptide and the formation of chemical groups, which incorporate the nitrogen at the N- terminus of a peptide.
  • the N-terminal modification may comprise the addition of one or more naturally occurring or non-naturally occurring amino acids to the VPAC2 receptor peptide agonist sequence, preferably there are not more than ten amino acids, with one amino acid being more preferred.
  • Naturally occurring amino acids which may be added to the N-terminus include methionine and isoleucine.
  • a modified amino acid added to the N-terminus may be D-histidine.
  • the following amino acids may be added to the N-terminus: SEQ ID NO: 91 Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys-Arg, wherein the Arg is linked to the N-temiinus of the peptide agonist.
  • any amino acids added to the N-terminus are linked to the N-terminus by a peptide bond.
  • the term "linked to” as used herein, with reference to the term N-terminal modification, includes the addition or attachment of amino acids or chemical groups directly to the N-terminus of the VPAC2 receptor agonist. The addition of the above N- terminal modifications may be achieved under normal coupling conditions for peptide bond formation.
  • the N-terminus of the peptide agonist may also be modified by the addition of an alkyl group (R), preferably a C 1 -C 16 alkyl group, to form (R)NH-.
  • the N-terminus of the peptide agonist may be modified by the addition of a group of the formula -C(O)R 1 to form an amide of the formula R 1 C(O)NH-.
  • the addition of a group of the formula -C(O)R 1 may be achieved by reaction with an organic acid of the formula R 1 COOH. Modification of the N-terminus of an amino acid sequence using acylation is demonstrated in the art (e.g. Gozes et at, J. Pharmacol Exp Ther, 273:161-167 (1995)).
  • Addition of a group of the formula -C(O)R 1 may result in the formation of a urea group (see WO 01/23240, WO 04/06839) or a carbamate group at the N-terminus. Also, the N-terminus may be modified by the addition of pyroglutamic acid, or 6-aminohexanoic acid.
  • the N-terminus of the peptide agonist may be modified by the addition of a group of the formula -SO 2 R 5 , to form a sulfonamide group at the N-terminus.
  • the N-terminus of the peptide agonist may also be modified by reacting with succinic anhydride to form a succinimide group at the N-terminus.
  • the succinimide group incorporates the nitrogen at the N-terminus of the peptide.
  • sequences of the present invention contain the standard single letter or three letter codes for the twenty naturally occurring amino acids.
  • the other codes used are defined as follows:
  • K(CO(CH 2 ) 2 SH) ⁇ -(3'-mercapto ⁇ ro ⁇ ionyl)-rysine
  • K(W) ⁇ -(L-tryptophyl)-lysine
  • VIP naturally occurs as a single sequence having 28 amino acids.
  • PACAP exists as either a 38 amino acid peptide (PACAP-38) or as a 27 amino acid peptide (PACAP-27) with an ami dated carboxyl (Miyata, et al., Biochem Biophys Res Commun, 170:643-648 (1990)).
  • the sequences for VIP, PACAP-27, and PACAP-38 are as follows:
  • naturally occurring amino acid means the twenty amino acids coded for by the human genetic code (i.e. the twenty standard amino acids). These twenty amino acids are: Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamine, Glutamic Acid, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine. Examples of “non-naturally occurring amino acids” include both synthetic amino acids and those modified by the body.
  • D-amino acids include D-amino acids, arginine-like amino acids (e.g., homoarginine), other amino acids having an extra methylene in the side chain (“homo” amino acids), and modified amino acids (e.g norleucine, lysine (isopropyl) - wherein the side chain amine of lysine is modified by an isopropyl group).
  • modified amino acids e.g norleucine, lysine (isopropyl) - wherein the side chain amine of lysine is modified by an isopropyl group.
  • amino acids such as ornithine, amino isobutyric acid and 2-aminobutanoic acid.
  • Selective refers to a VPAC2 receptor peptide agonist with increased selectivity for the VPAC2 receptor compared to other known receptors. The degree of selectivity is determined by a ratio of VPAC2 receptor binding affinity to VPACl receptor binding affinity and by a ratio of VPAC2 receptor binding
  • Insulinotropic activity refers to the ability to stimulate insulin secretion in response to elevated glucose levels, thereby causing glucose uptake by cells and decreased plasma glucose levels. Insulinotropic activity can be assessed by methods known in the art, including using experiments that measure VPAC2 receptor binding activity or receptor activation (e.g. insulin secretion by insulinoma cell lines or islets, intravenous glucose tolerance test (IVGTT), intraperitoneal glucose tolerance test (IPGTT), and oral glucose tolerance test (OGTT)). Insulinotropic activity is routinely measured in humans by measuring insulin levels or C-peptide levels. Selective VPAC2 receptor peptide agonists of the present invention have insulinotropic activity.
  • In vitro potency is the measure of the ability of a peptide to activate the VPAC2 receptor in a cell-based assay. In vitro potency is expressed as the "EC 5 o" which is the effective concentration of compound that results in a 50% of maximum increase in activity in a single dose-response experiment. For the purposes of the present invention, in vitro potency is determined using two different assays: DiscoveRx and Alpha Screen. See Examples 3 and 5 for further details of these assays. Whilst these assays are performed in different ways, the results demonstrate a general correlation between the two assays.
  • Percent (%) sequence identity is used to denote sequences which when aligned have similar (identical or conservatively replaced) amino acids in like positions or regions, where identical or conservatively replaced amino acids are those which do not alter the activity or function of the protein as compared to the starting protein. For example, two amino acid sequences with at least 85% identity to each other have at least 85% similar (identical or conservatively replaced residues) in a like position when aligned optimally allowing for up to 3 gaps, with the proviso that in respect of the gaps a total of not more than 15 amino acid residues is affected.
  • the reference peptide used for the percentage sequence identity calculations herein is:
  • Percent sequence identity may be calculated by determining the number of residues that differ between a peptide encompassed by the present invention and a reference peptide such as P487 (SEQ ID NO: 55), taking that number and dividing it by the number of amino acids in the reference peptide (e.g. 39 amino acids for P487), multiplying the result by 100, and subtracting that resulting number from 100. For example, a sequence having 39 amino acids with four amino acids that are different from P487 would have a percent (%) sequence identity of 90% (e.g. 100 - ((4 / 39) x 100)).
  • the number of residues that differ from the P487 sequence will include the additional amino acids over 39 for purposes of the aforementioned calculation.
  • a sequence having 40 amino acids, with four amino acids different from the 39 amino acids in the P487 sequence and with one additional amino acid at the carboxy terminus which is not present in the P487 sequence would have a total of five amino acids that differ from P487.
  • this sequence would have a percent (%) sequence identity of 87% (e.g. 100 - ((5 / 39) x 100)).
  • the degree of sequence identity may be determined using methods well known in the art (see, for example, Wilbur, WJ. and Lipman, DJ., Proc. Natl. Acad.
  • Clustal W is a general purpose multiple sequence alignment program for DNA or proteins. It produces biologically meaningful multiple sequence alignments of divergent sequences. It calculates the best match for the selected sequences, and lines them up so that the identities, similarities and differences can be seen. Evolutionary relationships can be seen via viewing Cladograms or Phylograms.
  • the sequence for a selective VPAC2 receptor peptide agonist of the present invention is selective for the VPAC2 receptor and preferably has a sequence identity in the range of 60% to 70%, 60% to 65%, 65% to 70%, 70% to 80%, 70% to 75%, 75% to 80%, 80% to 90%, 80% to 85%, 85% to 90%, 90% to 97%, 90% to 95%, or 95% to 97%, with P487 (SEQ ID NO: 55).
  • the sequence has a sequence identity of greater than 82% with P487 (SEQ ID NO: 55). More preferably, the sequence has greater than 90% sequence identity with P487 (SEQ ID NO: 55). Even more preferably, the sequence has greater than 92% sequence identity with P487 (SEQ ID NO: 55).
  • sequence has greater than 95% sequence identity or 97% sequence identity with P487 (SEQ ID NO: 55).
  • C 1 -C 16 alkyl as used herein means a monovalent saturated straight, branched or cyclic chain hydrocarbon radical having from 1 to 16 carbon atoms or when cyclic, having from 3 to 16 carbon atoms.
  • Ci-C 16 alkyl includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n- heptyl, n-octyl, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
  • the C 1 -C 16 alkyl group may be optionally substituted with one or more substituents including, for example, aryl, C 1 -C 6 alkoxy, -OH, halogen, -CF 3 and -SH.
  • C 1 - C 6 alkyl as used herein means a monovalent saturated straight, branched or cyclic chain hydrocarbon radical having from 1 to 6 carbon atoms or when cyclic, having from 3 to 6 carbon atoms.
  • Ci-C 6 alkyl includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl.
  • the Ci-C 6 alkyl group may be optionally substituted with one or more substituents.
  • C 2 -C 6 alkenyl as used herein means a monovalent straight, branched or cyclic chain hydrocarbon radical having at least one double bond and having from 2 to 6 carbon atoms or when cyclic, having from 3 to 6 carbon atoms.
  • C 2 -C 6 alkenyl includes vinyl, prop-2-enyl, but-3-enyl, pent-4-enyl and isopropenyl.
  • the C 2 -C 6 alkenyl group may be optionally substituted with one or more substituents.
  • C 2 -C 6 alkynyl as used herein means a monovalent straight or branched chain hydrocarbon radical having at least one triple bond and having from 2 to 6 carbon atoms.
  • C 2 -C 6 alkynyl includes prop-2-ynyl, but-3-ynyl and pent-4-ynyl.
  • the C 2 -C 6 alkynyl may be optionally substituted with one or more substituents.
  • C 1 -C 6 alkoxy as used herein means a monovalent unsubstituted saturated straight-chain or branched-chain hydrocarbon radical having from 1 to 6 carbon atoms linked to the point of substitution by a divalent O radical.
  • C 1 -C 6 alkoxy includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy.
  • the C 1 -C 6 alkoxy group may be optionally substituted with one or more substituents.
  • halo or halogen means fluorine, chlorine, bromine or iodine.
  • aryl when used alone or as part of a group is a 5 to 10 membered aromatic or heteroaromatic group including a phenyl group, a 5 or 6- membered monocyclic heteroaromatic group, each member of which may be optionally substituted with 1, 2, 3, 4 or 5 substituents (depending upon the number of available substitution positions), a naphthyl group or an 8-, 9- or 10- membered bicyclic heteroaromatic group, each member of which may be optionally substituted with 1, 2, 3, 4, 5 or 6 substituents (depending on the number of available substitution positions).
  • suitable substitutions include Ci-C 6 alkyl, C 2 -C 6 alkenyl, C 2 -C 6 alkynyl, -NH 2 , -OH, halogen, -SH and CF 3 .
  • aryl C 1 -C 4 alkyl as used herein means a C 1 -C 4 alkyl group substituted with an aryl.
  • aryl C 1 -C 4 alkyl includes benzyl, 1-phenylethyl ( ⁇ - methylbenzyl), 2-phenylethyl, 1-naphthalenemethyl or 2-naphthalenemethyl.
  • naphthyl includes 1-naphthyl, and 2-naphthyl. 1-naphthyl is preferred.
  • benzyl as used herein means a monovalent unsubstituted phenyl radical linked to the point of substitution by a -CH 2 - group.
  • 5- or 6-membered monocyclic heteroaromatic group as used herein means a monocyclic aromatic group with a total of 5 or 6 atoms in the ring wherein from 1 to 4 of those atoms are each independently selected from N, O and S.
  • Preferred groups have 1 or 2 atoms in the ring which are each independently selected from N, O and S.
  • 5-membered monocyclic heteroaromatic groups include pyrrolyl (also called azolyl), furanyl, thienyl, pyrazolyl (also called lH-pyrazolyl and 1,2-diazolyl), imidazolyl, oxazolyl (also called 1,3-oxazolyl), isoxazolyl (also called 1,2-oxazolyl), thiazolyl (also called 1,3-thiazolyl), isothiazolyl (also called 1,2-thiazolyl), triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, oxatriazolyl and thiatriazolyl.
  • 6- membered monocyclic heteroaromatic groups include pyridinyl, pyrimidyl, pyrazinyl, pyridazinyl and triazinyl.
  • 8-, 9- or 10-membered bicyclic heteroaromatic group as used herein means a fused bicyclic aromatic group with a total of 8, 9 or 10 atoms in the ring system wherein from 1 to 4 of those atoms are each independently selected from N, O and S.
  • Preferred groups have from 1 to 3 atoms in the ring system which are each independently selected from N, O and S.
  • Suitable 8-membered bicyclic heteroaromatic groups include imidazo[2, 1-b] [1 ,3]thiazolyl, thieno[3 ,2-b]thienyl, thieno[2,3-d] [ 1 ,3]thiazolyl and thieno[2,3-d]imidazolyl.
  • Suitable 9-membered bicyclic heteroaromatic groups include indolyl, isoindolyl, benzofuranyl (also called benzo[b]furanyl), isobenzofuranyl (also called benzo[c]furanyl), benzothienyl (also called benzo[b]thienyl), isobenzothienyl (also called benzo[c]thienyl), indazolyl, benzimidazolyl, 1,3-benzoxazolyl, 1,2-benzisoxazolyl, 2,1-benzisoxazolyl, 1,3-benzothiazolyl, 1,2-benzoisothiazolyl, 2,1-benzoisothiazolyl, benzotriazolyl, 1,2,3-benzoxadiazolyl, 2,1,3-benzoxadiazolyl, 1,2,3-benzothiadiazolyl, 2,1,3-benzothiadiazolyl, thienopyridinyl, purinyl and
  • Suitable 10- membered bicyclic heteroaromatic groups include quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, 1,5-naphthyridyl, 1,6-naphthyridyl, 1,7-naphthyridyl and 1,8- naphthyridyl.
  • a VPAC2 receptor peptide agonist comprising a peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199, and a C-terminal extension selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH 2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH 2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH 2 (SEQ ID NO: 10), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH 2 (SEQ ID NO: 12).
  • GGPSSGAPPPS SEQ ID NO: 5
  • GGPSSGAPPPS-NH 2 SEQ ID NO: 6
  • GGPSSGAPPPC SEQ ID NO: 7
  • GGPSSGAPPPC-NH 2 SEQ ID NO: 8
  • GRPSSGAPPPS SEQ ID NO:
  • the C-terminal extension is selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH 2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH 2 (SEQ ID NO: 8), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH 2 (SEQ ID NO: 12).
  • a VPAC2 receptor peptide agonist comprising a peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199 and a C-terminal extension selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH 2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH 2 (SEQ ID N0:8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH 2 (SEQ ID NO: 10),
  • GGPSSGAPPPCC SEQ ID NO: 11
  • GGPSSGAPPPCC-NH 2 SEQ ID NO: 12
  • a VPAC2 receptor peptide agonist comprising an amino acid sequence of Formula 4 (SEQ ID NO: 4) and a C-terminal extension selected from GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH 2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH 2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9),
  • the N-terminal modification is the addition of acetyl or hexanoyl.
  • VPAC2 receptor peptide agonist comprising an amino acid sequence of
  • Formula 4 (SEQ ID NO: 4), wherein Xaai 5 is Aib, Xaa 20 is Aib and Xaa ⁇ , Xaa 2 i, Xaa 27 and Xaa 2 g are all Orn, and a C-terminal extension selected from GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH 2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH 2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH 2 (SEQ ID NO: 10), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH 2 (SEQ ID NO: 12), and wherein the VPAC2 receptor peptide agonist further comprises a N-terminal modification, which modification is the addition of acetyl, propionyl, butyryl, pentanoyl,
  • Xaa 15 is Aib
  • Xaa 20 is Aib
  • Xaaj 2 Xaa 21 , Xaa 27 and Xaa 2 g are all Orn
  • Xaag is GIu
  • Xaa 9 is GIn
  • Xaaio is Tyr(OMe).
  • Xaa 15 is Aib
  • Xaa 2 o is Aib
  • Xaa 12 , Xaa 21 , Xaa 27 and Xaa 28 are all Orn
  • Xaa 8 is GIu
  • Xaa 9 is GIn
  • Xaa 10 is Tyr(OMe)
  • Xaa 23 and/or Xaa 25 is Aib.
  • the present invention encompasses the discovery that specific amino acids added to the C-terminus of a peptide sequence for a VPAC2 receptor peptide agonist may protect the peptide as well as may enhance activity, selectivity, and/or potency.
  • these C-terminal extensions may stabilize the helical structure of the peptide and stabilize sites located near to the C-terminus, which are prone to enzymatic cleavage.
  • many of the C-terminally extended peptides disclosed herein may be more selective for the VPAC2 receptor and may be more potent than VIP, PACAP, and other known VPAC2 receptor peptide agonists.
  • An example of a preferred C-terminal extension is the extension peptide of exendin-4 as the C-capping sequence.
  • Exendin-4 is found in the salivary excretions from the GiIa Monster, Heloderma Suspectum, (Eng et al, J.BioLChem., 267(11):7402-7405 (1992)).
  • Other examples of C-terminal extensions are the C-terminal sequences of helodermin and helospectin. Helodermin and helospectin are also found in the salivary excretions of the GiIa Monster.
  • VPAC2 receptor peptide agonist may enhance potency and/or provide stability against DPP-IV cleavage.
  • VIP and some known VPAC2 receptor peptide agonists are susceptible to cleavage by various enzymes and, thus, have a short in vivo half-life.
  • Various enzymatic cleavage sites in the VPAC2 receptor peptide agonists are discussed below. The cleavage sites are discussed relative to the amino acid positions in VIP (SEQ ID NO: 14), and are applicable to the sequences noted herein.
  • DPP-IV dipeptidyl-peptidase-IV
  • the N-terminal modification is the addition of acetyl or hexanoyl.
  • chymotrypsin cleavage sites in wild-type VIP between the amino acids 10 and 11 (tyrosine and threonine) and those at 22 and 23 (tyrosine and leucine). Making substitutions at position 10 and/or 11 and position 22 and/or 23 may increase the stability of the peptide at these sites. For example, substitution of tyrosine at position 10 and/or position 22 with Tyr(OMe) may increase stability.
  • trypsin cleavage site between the amino acids at positions 12 and 13 of wild-type VIP. Certain amino acids render the peptide less susceptible to cleavage at this site, for example, ornithine and homoarginine at position 12 and amino isobutyric acid at position 13.
  • VPAC2 receptor peptide agonists In wild-type VIP, and in numerous VPAC2 receptor peptide agonists known in the art, there are cleavage sites between the basic amino acids at positions 14 and 15 and between those at positions 20 and 21.
  • the selective VPAC2 receptor peptide agonists of the present invention may have improved proteolytic stability in-vivo due to substitutions at these sites.
  • the preferred substitutions at these sites are those which render the peptide less susceptible to cleavage by trypsin-like enzymes, including trypsin.
  • leucine at position 14, amino isobutyric acid at position 15, amino isobutyric acid and glutamine at position 20, and ornithine at position 21 are all preferred substitutions which may lead to improved stability.
  • VPAC2 receptor peptide agonist encompassing the amino acids at positions 27, 28, and 29 is also susceptible to enzyme cleavage.
  • the addition of a C-terminal extension may render the peptide agonist more stable against neuroendopeptidase (NEP).
  • NEP neuroendopeptidase
  • This region may also be attacked by trypsin-like enzymes. If that occurs, the peptide agonist may lose its C-terminal extension with the additional carboxypeptidase activity leading to an inactive form of the peptide.
  • Preferred substitutions which may increase resistance to cleavage in this region include ornithine at position 27, ornithine, amino isobutyric acid, or glutamine at position 28 and ornithine, or lysine at position 29.
  • the selective VPAC2 peptide receptor agonists of the present invention may also encompass peptides with enhanced selectivity for the VPAC2 receptor, increased potency, and/or increased stability compared with some peptides known in the art.
  • the potency and selectivity of various VPAC2 receptor peptide agonists of the present invention is reported in Examples 3, 4 and 5.
  • Table 1 in Example 3 provides a list of selective VPAC2 receptor peptide agonists and their corresponding in vitro potency results.
  • the selective VPAC2 receptor peptide agonists of the present invention have an EC 50 value less than 10 nM.
  • the selective VPAC2 receptor peptide agonists of the present invention have an EC5 0 value less than 2 nM.
  • the EC 50 value is less than 1 nM.
  • the EC 50 value is less than 0.5 nM.
  • Example 4 provides a list of VPAC2 receptor peptide agonists and their corresponding binding affinity results for human VPAC2, VPACl, and PACl. See Example 4 for further details of these assays.
  • the degree of selectivity is determined by a ratio of VPAC2 receptor binding affinity to VPACl receptor binding affinity and by a ratio of VPAC2 receptor binding affinity to PACl receptor binding affinity.
  • the agonists of the present invention have a selectivity ratio where the affinity for the VPAC2 receptor is at least 50 times greater than for the VPACl and/or for PACl receptors. More preferably, this affinity is at least 100 times greater for VPAC2 than for VPACl and/or for PACl.
  • the affinity is at least 200 times greater for VPAC2 than for VPACl and/or for PACl. Still more preferably, the affinity is at least 500 times greater for VPAC2 than for VPACl and/or for PACl. Yet more preferably, the ratio is at least 1000 times greater for VPAC2 than for VPACl and/or for PACl.
  • selective VPAC2 receptor peptide agonists also include pharmaceutically acceptable salts of the agonists described herein.
  • a selective VPAC2 receptor peptide agonist of this invention can possess a sufficiently acidic, a sufficiently basic, or both functional groups, and accordingly react with any of a number of inorganic bases, and inorganic and organic acids, to form a salt.
  • Acids commonly employed to form acid addition salts are inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and the like, and organic acids such as p- toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromophenyl-sulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, trifluoroacetic acid, and the like.
  • inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and the like
  • organic acids such as p- toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromophenyl-sulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, trifluoroacetic acid, and
  • salts include the sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caproate, heptanoate, propiolate, oxalate, malonate, succinate, suberate, sebacate, fumarate, maleate, butyne-l,4-dioate, hexyne-l,6-dioate, benzoate, chlorobenzoate, methylbenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, phthalate, sulfonate, xylenesulfonate, phenylacetate, phenylpropionate, phenylbut
  • Base addition salts include those derived from inorganic bases, such as ammonium or alkali or alkaline earth metal hydroxides, carbonates, bicarbonates, and the like.
  • bases useful in preparing the salts of this invention thus include sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, and the like.
  • the selective VPAC2 receptor peptide agonists of the present invention are preferably formulated as pharmaceutical compositions. Standard pharmaceutical formulation techniques may be employed such as those described in Remington' s Pharmaceutical Sciences, Mack Publishing Company, Easton, PA.
  • the selective VPAC2 receptor peptide agonists of the present invention may be formulated for administration through the buccal, topical, oral, transdermal, nasal, or pulmonary route, or for parenteral administration.
  • Parenteral administration can include, for example, systemic administration, such as by intramuscular, intravenous, subcutaneous, intradermal, or intraperitoneal injection.
  • the selective VPAC2 receptor peptide agonists can be administered to the subject in conjunction with an acceptable pharmaceutical carrier, diluent, or excipient as part of a pharmaceutical composition for treating NLDDM, or the disorders discussed below.
  • the pharmaceutical composition can be a solution or, if administered parenterally, a suspension of the VPAC2 receptor peptide agonist or a suspension of the VPAC2 receptor peptide agonist complexed with a divalent metal cation such as zinc.
  • Suitable pharmaceutical carriers may contain inert ingredients which do not interact with the peptide or peptide derivative.
  • Suitable pharmaceutical carriers for parenteral administration include, for example, sterile water, physiological saline, bacteriostatic saline (saline containing about 0.9% mg/ml benzyl alcohol), phosphate-buffered saline, Hank's solution, Ringer's-lactate and the like.
  • suitable excipients include lactose, dextrose, sucrose, trehalose, sorbitol, and mannitol.
  • the VPAC2 receptor peptide agonists of the invention may be formulated for administration such that blood plasma levels are maintained in the efficacious range for extended time periods.
  • VPAC2 receptor peptide agonists can be encapsulated into microspheres composed of a commercially available, biocompatible, biodegradable polymer, poly(lactide-co-glycolide)-COOH and olive oil as a filler (see Joseph, et al. Diabetologia 43:1319-1328 (2000)).
  • Medisorb® and Prolease® biodegradable polymers from Alkermes.
  • Medisorb® polymers can be produced with any of the lactide isomers. Lactiderglycolide ratios can be varied between 0:100 and 100:0 allowing for a broad range of polymer properties. This allows for the design of delivery systems and implantable devices with resorption times ranging from weeks to months.
  • Emisphere has published numerous articles discussing oral delivery technology for peptides and proteins. For example, see WO 95/28838 by Leone-bay et al. which discloses specific carriers comprised of modified amino acids to facilitate absorption.
  • VPAC2 receptor peptide agonists described herein can be used to treat subjects with a wide variety of diseases and conditions.
  • Agonists encompassed by the present invention exert their biological effects by acting at a receptor referred to as the VPAC2 receptor.
  • Subjects with diseases and/or conditions that respond favourably to VPAC2 receptor stimulation or to the administration of VPAC2 receptor peptide agonists can therefore be treated with the VPAC2 agonists of the present invention. These subjects are said to "be in need of treatment with VPAC2 agonists" or "in need of VPAC2 receptor stimulation".
  • the selective VPAC2 receptor peptide agonists of the present invention may be employed to treat diabetes, including both type 1 and type 2 diabetes (non-insulin dependent diabetes mellitus or NIDDM).
  • the agonists may also be used to treat subjects requiring prophylactic treatment with a VPAC2 receptor agonist, e.g., subjects at risk for developing NIDDM. Such treatment may delay the onset of diabetes and diabetic complications.
  • Additional subjects which may be treated with the agonists of the present invention include those with impaired glucose tolerance (IGT) (Expert Committee on Classification of Diabetes Mellitus, Diabetes Care 22 (Supp.
  • the selective VPAC2 receptor peptide agonists may be used to prevent subjects with impaired glucose tolerance from proceeding to develop NIDDM, prevent pancreatic ⁇ -cell deterioration, induce ⁇ -cell proliferation, improve ⁇ - cell function, activate dormant ⁇ -cells, differentiate cells into ⁇ -cells, stimulate ⁇ -cell replication, and inhibit ⁇ -cell apoptosis.
  • VPAC2 receptor peptide agonists of the invention include: Maturity-Onset Diabetes of the Young (MODY) (Herman, et al., Diabetes 43:40, 1994); Latent Autoimmune Diabetes Adult (LADA) (Zimmet, et al., Diabetes Med. 11:299, 1994); gestational diabetes (Metzger, Diabetes, 40:197, 1991); metabolic syndrome X, dyslipidemia, hyperglycemia, hyperinsulinemia, hypertriglyceridemia, and insulin resistance.
  • MODY Maturity-Onset Diabetes of the Young
  • LADA Latent Autoimmune Diabetes Adult
  • gestational diabetes Metzger, Diabetes, 40:197, 1991
  • metabolic syndrome X dyslipidemia, hyperglycemia, hyperinsulinemia, hypertriglyceridemia, and insulin resistance.
  • the selective VPAC2 receptor peptide agonists of the invention may also be used to treat secondary causes of diabetes (Expert Committee on Classification of Diabetes Mellitus, Diabetes Care 22 (Supp. 1):S5, 1999).
  • Such secondary causes include glucocorticoid excess, growth hormone excess, pheochromocytoma, and drug-induced diabetes.
  • Drugs that may induce diabetes include, but are not limited to, pyriminil, nicotinic acid, glucocorticoids, phenytoin, thyroid hormone, ⁇ -adrenergic agents, ⁇ - interferon and drugs used to treat HIV infection.
  • the selective VPAC2 receptor peptide agonists of the present invention may be effective in the suppression of food intake and the treatment of obesity.
  • the selective VPAC2 receptor peptide agonists of the present invention may also be effective in the prevention or treatment of such disorders as atherosclerotic disease, hyperlipidemia, hypercholesteremia, low HDL levels, hypertension, primary pulmonary hypertension, cardiovascular disease (including atherosclerosis, coronary heart disease, and coronary artery disease), cerebrovascular disease and peripheral vessel disease; and for the treatment of lupus, polycystic ovary syndrome, carcinogenesis, hyperplasia, male and female reproduction problems, sexual disorders, ulcers, sleep disorders, disorders of lipid and carbohydrate metabolism, circadian dysfunction, growth disorders, disorders of energy homeostasis, immune diseases including autoimmune diseases (e.g., systemic lupus erythematosus), as well as acute and chronic inflammatory diseases, rheumatoid arthritis, and septic shock.
  • autoimmune diseases e.g., systemic lupus erythematosus
  • acute and chronic inflammatory diseases rheumatoid arthritis
  • the selective VPAC2 receptor peptide agonists of the present invention may also be useful for treating physiological disorders related to, for example, cell differentiation to produce lipid accumulating cells, regulation of insulin sensitivity and blood glucose levels, which are involved in, for example, abnormal pancreatic ⁇ -cell function, insulin secreting tumors and/or autoimmune hypoglycemia due to autoantibodies to insulin, autoantibodies to the insulin receptor, or autoantibodies that are stimulatory to pancreatic ⁇ -cells, macrophage differentiation which leads to the formation of atherosclerotic plaques, inflammatory response, carcinogenesis, hyperplasia, adipocyte gene expression, adipocyte differentiation, reduction in the pancreatic ⁇ -cell mass, insulin secretion, tissue sensitivity to insulin, liposarcoma cell growth, polycystic ovarian disease, chronic anovulation, hyperandrogenism, progesterone production, steroidogenesis, redox potential and oxidative stress in cells, nitric oxide synthas
  • the selective VPAC2 receptor peptide agonists of the invention may be used for treatment of asthma (Bolin, et al., Biopolymer 37:57-66 (1995); U.S. Patent No. 5,677,419; showing that polypeptide R3P0 is active in reducing guinea pig tracheal smooth muscle); for hypotension induction (VDP induces hypotension, tachycardia, and facial flushing in asthmatic patients (Morice, et al., Peptides 7:279-280 (1986); Morice, et al., Lancet 2:1225-1227 (1983)); for the treatment of male reproduction problems (Siow, et al. , Arch. Androl.
  • an “effective amount” of a selective VPAC2 receptor peptide agonist is the quantity that results in a desired therapeutic and/or prophylactic effect without causing unacceptable side effects when administered to a subject in need of VPAC2 receptor stimulation.
  • a “desired therapeutic effect” includes one or more of the following: 1) an amelioration of the symptom(s) associated with the disease or condition; 2) a delay in the onset of symptoms associated with the disease or condition; 3) increased longevity compared with the absence of the treatment; and 4) greater quality of life compared with the absence of the treatment.
  • an "effective amount" of a VPAC2 agonist for the treatment of NIDDM is the quantity that would result in greater control of blood glucose concentration than in the absence of treatment, thereby resulting in a delay in the onset of diabetic complications such as retinopathy, neuropathy, or kidney disease.
  • An "effective amount” of a selective VPAC2 receptor peptide agonist for the prevention of NEDDM is the quantity that would delay, compared with the absence of treatment, the onset of elevated blood glucose levels that require treatment with anti-hypoglycemic drugs such as sulfonylureas, thiazolidinediones, insulin, and/or bisguanidines.
  • an "effective amount" of the selective VPAC2 receptor peptide agonist administered to a subject will also depend on the type and severity of the disease and on the characteristics of the subject, such as general health, age, sex, body weight and tolerance to drugs.
  • the dose of selective VPAC2 peptide receptor agonist effective to normalize a patient's blood glucose will depend on a number of factors, among which are included, without limitation, the subject's sex, weight and age, the severity of inability to regulate blood glucose, the route of administration and bioavailability, the pharmacokinetic profile of the peptide, the potency, and the formulation.
  • a typical dose range for the selective VPAC2 receptor peptide agonists of the present invention will range from about 1 ⁇ g per day to about 5000 ⁇ g per day.
  • the dose ranges from about 1 ⁇ g per day to about 2500 ⁇ g per day, more preferably from about 1 ⁇ g per day to about 1000 ⁇ g per day. Even more preferably, the dose ranges from about 5 ⁇ g per day to about 100 ⁇ g per day.
  • a further preferred dose range is from about 10 ⁇ g per day to about 50 ⁇ g per day. Most preferably, the dose is about 20 ⁇ g per day.
  • a "subject” is a mammal, preferably a human, but can also be an animal, e.g., companion animals (e.g., dogs, cats, and the like), farm animals (e.g., cows, sheep, pigs, horses, and the like) and laboratory animals (e.g., rats, mice, guinea pigs, and the like).
  • the selective VPAC2 receptor peptide agonists of the present invention can be prepared by using standard methods of solid-phase peptide synthesis techniques. Peptide synthesizers are commercially available from, for example, Rainin-PTI Symphony Peptide Synthesizer (Tucson, AZ).
  • Solid phase peptide synthesizers can be used according to manufacturer's instructions for blocking interfering groups, protecting the amino acid to be reacted, coupling, decoupling, and capping of unreacted amino acids.
  • an ⁇ -iV-protected amino acid and the N-terminal amino acid on the growing peptide chain on a resin is coupled at room temperature in an inert solvent such as dimethylformamide, N-methylpyrrolidone or methylene chloride in the presence of coupling agents such as dicyclohexylcarbodiimide and 1-hydroxybenzotriazole and a base such as diisopropylethylamine.
  • the ⁇ -iV-protecting group is removed from the resulting peptide resin using a reagent such as trifluoroacetic acid or piperidine, and the coupling reaction repeated with the next desired iV-protected amino acid to be added to the peptide chain.
  • Suitable amine protecting groups are well known in the art and are described, for example, in Green and Wuts, "Protecting Groups in Organic Synthesis", John Wiley and Sons, 1991. Examples include t-butyloxycarbonyl (tBoc) and fluorenylmethoxycarbonyl (Fmoc).
  • the selective VPAC2 receptor peptide agonists may also be synthesized using standard automated solid-phase synthesis protocols using t-butoxycarbonyl- or fluorenylmethoxycarbonyl-alpha-amino acids with appropriate side-chain protection. After completion of synthesis, modification of the N-terminus may be accomplished by reacting the ⁇ -amino group with, for example: (i) active esters (using similar protocols as described above for the introduction of an or-iV-protected amino acid); (ii) aldehydes in presence of a reducing agent (reductive amination procedure); and (iii) guanidation reagents.
  • peptides are cleaved from the solid-phase support with simultaneous side- chain deprotection using standard hydrogen fluoride methods or trifluoroacetic acid (TFA). Crude peptides are then further purified using Reversed-Phase Chromatography on VYDAC Cl 8 columns using acetonitrile gradients in 0.1% trifluoroacetic acid (TFA). To remove acetonitrile, peptides are lyophilized from a solution containing 0.1 % TFA, acetonitrile and water. Purity can be verified by analytical reversed phase chromatography. Identity of peptides can be verified by mass spectrometry. Peptides can be solubilized in aqueous buffers at neutral pH.
  • the peptide agonists of the present invention may also be made by recombinant methods known in the art using both eukaryotic and prokaryotic cellular hosts.
  • Boc Ser(Bzl)-PAM resin is placed in a standard 60 mL reaction vessel. Double couplings are run on an Applied Biosystems ABI430A peptide synthesizer.
  • Arg-Tosyl Asp- ⁇ -cyclohexyl ester (OcHx), Glu- ⁇ -cycohexyl ester (OcHx), His-benzyloxymethyl(BOM), Lys-2-chlorobenzyloxycarbonyl (2C1-Z), Ser-O- benzyl ether (OBzI), Thr-O-benzyl ether (OBzI), Trp-formyl (CHO), and Tyr-2- bromobenzyloxycarbonyl (2Br-Z).
  • Trifluoroacetic acid (TFA), di-isopropylethylamine (DIEA), 0.5 M hydroxybenzotriazole (HOBt) in DMF and 0.5 M dicyclohexylcarbodiimide (DCC) in dichloromethane are purchased from PE- Applied Biosystems (Foster City, CA).
  • Dimethylformamide (DMF-Burdick and Jackson) and dichloromethane (DCM- Mallinkrodt) are purchased from Mays Chemical Co. (Indianapolis, IN).
  • Standard double couplings are run using either symmetric anhydride or HOBt esters, both formed using DCC.
  • the N-terminal Boc group is removed and the peptidyl resins are treated with 20% piperidine in DMF to deformylate the Trp side chain if Trp is present in the sequence.
  • For N-terminal acylation four-fold excess of symmetric anhydride of the corresponding acid is added onto the peptide resin.
  • the symmetric anhydride is prepared by diisopropylcarbodiimide (DIC) activation in DCM. The reaction is allowed to proceed for 4 hours and monitored by ninhydrin test. After washing with DCM, the resins are transferred to a TEFLON reaction vessel and are dried in vacuo.
  • Cleavages are done by attaching the reaction vessels to a HF (hydrofluoric acid) apparatus (Penninsula Laboratories). 1 mL m-cresol per gram/resin is added and 10 mL HF (purchased from AGA, Indianapolis, IN) is condensed into the pre-cooled vessel. 1 mL DMS per gram resin is added when methionine is present. The reactions are stirred one hour in an ice bath. The HF is removed in vacuo. The residues are suspended in ethyl ether. The solids are filtered and are washed with ether. Each peptide is extracted into aqueous acetic acid and either is freeze dried or is loaded directly onto a reverse- phase column.
  • HF hydrofluoric acid
  • FMOC amino acids are purchased from GlycoPep (Chicago, IL), and NovaBiochem (La Jolla, CA): Arg-2,2,4,6,7-pentamethyldihydrobenzofuran-5- sulfonyl (Pbf), Asn-trityl (TA) 1 Asp- ⁇ -t-Butyl ester (tBu), Glu- ⁇ -t-butyl ester (tBu), GIn- trityl (TA), His-trityl (TA), Lys-t-butyloxycarbonyl (Boc), Ser-t-butyl ether (OtBu), Thr-t- butyl ether (OtBu), Trp-t-butyloxycarbonyl (Boc), Tyr-t-butyl ether (OtBu).
  • DCM-Mallinkrodt Solvents dimethylformamide (DMF-Burdick and Jackson), N-methyl pyrrolidone (NMP-Burdick and Jackson), dichloromethane (DCM-Mallinkrodt) are purchased from Mays Chemical Co. (Indianapolis, IN).
  • HABt Hydroxybenzotriazole
  • DIC di-isopropylcarbodiimide
  • DJJEA di- isopropylethylamine
  • Pip piperidine
  • AU amino acids are dissolved in 0.3 M in DMF.
  • Three hour DIC/HOBt activated couplings are run after 20 minutes deprotection using 20% Piperidine/DMF.
  • Each resin is washed with DMF after deprotections and couplings.
  • the peptidyl resins are washed with DCM and are dried in vacuo in the reaction vessel.
  • For N-terminal acylation four-fold excess of symmetric anhydride of the corresponding acid is added onto the peptide resin.
  • the symmetric anhydride is prepared by DIC activation in DCM.
  • the reaction is allowed to proceed for 4 hours and monitored by ninhydrin test.
  • the peptide resin is then washed with DCM and dried in vacuo.
  • the cleavage reaction is mixed for 2 hours with a cleavage cocktail consisting of
  • DiscoveRx A CHO-S cell line stably expressing human VPAC2 receptor in a 96- well microtiter plate is seeded with 50,000 cells/well the day before the assay. The cells are allowed to attach for 24 hours in 200 ⁇ ,L culture medium. On the day of the experiment, the medium is removed. Also, the cells are washed twice. The cells are incubated in assay buffer plus IBMX for 15 minutes at room temperature. Afterwards, the stimuli are added and are dissolved in assay buffer. The stimuli are present for 30 minutes. Then, the assay buffer is gently removed. The cell lysis reagent of the DiscoveRx cAMP kit is added.
  • VPACl receptor CHO-PO cells are transiently transfected with human VPACl receptor DNA using commercially available transfection reagents (Lipofectamine from Invitrogen). The cells are seeded at a density of 10,000/well in a 96-well plate and are allowed to grow for 3 days in 200 mL culture medium. At day 3, the assay described above for the VPAC2 receptor cell line is performed. Results for each agonist are the mean of two independent runs. VPACl results are only generated using the DiscoveRx assay. The typically tested concentrations of peptide are: 1000, 300, 100, 10, 1, 0.3, 0.1, 0.01, 0.001, 0.0001 and 0 nM.
  • Alpha screen Cells are washed in the culture flask once with PBS. Then, the cells are rinsed with enzyme free dissociation buffer. The dissociated cells are removed. The cells are then spun down and washed in stimulation buffer. For each data point, 50,000 cells suspended in stimulation buffer are used. To this buffer, Alpha screen acceptor beads are added along with the stimuli. This mixture is incubated for 60 minutes. Lysis buffer and Alpha screen donor beads are added and are incubated for 60 to 120 minutes. The Alpha screen signal (indicative of intracellular cAMP levels) is read in a suitable instrument (e.g. AlphaQuest from Perkin-Elmer). Steps including Alpha screen donor and acceptor beads are performed in reduced light.
  • a suitable instrument e.g. AlphaQuest from Perkin-Elmer. Steps including Alpha screen donor and acceptor beads are performed in reduced light.
  • the EC 50 for cAMP generation is calculated from the raw signal or is based on absolute cAMP levels as determined by a standard curve performed on each plate.
  • Results for each agonist are, at minimum, from two analyses performed in a single run. For some agonists, the results are the mean of more than one run.
  • the tested peptide concentrations are: 10000, 1000, 100, 10, 3, 1, 0.1, 0.01, 0.003, 0.001, 0.0001 and 0.00001 nM.
  • Binding assays Membrane prepared from a stable VPAC2 cell line (see Example 3) or from cells transiently transfected with human VPACl or PACl are used. A filter binding assay is performed using 1251-labeled VIP for VPACl and VPAC2 and 1251- labeled PACAP-27 for PACl as the tracers.
  • the solutions and equipment include:
  • Presoak solution 0.5 % Polyethyleneamine in Aqua dest Buffer for flushing filter plates: 25 mM HEPES pH 7.4
  • Blocking buffer 25 mM HEPES pH 7.4; 0.2 % protease free BSA
  • Assay buffer 25 mM HEPES pH 7.4; 0.5 % protease free BSA
  • Dilution and assay plate PS-Microplate, U form
  • the presoak solution is aspirated by vacuum filtration.
  • the plates are flushed twice with 200 ⁇ L flush buffer.
  • 200 ⁇ L blocking buffer is added to the filter plate.
  • the filter plate is then incubated with 200 ⁇ L presoak solution for 1 hour at room temperature.
  • the assay plate is filled with 25 ⁇ L assay buffer, 25 ⁇ L membranes (2.5 ⁇ g) suspended in assay buffer, 25 ⁇ L compound (agonist) in assay buffer, and 25 ⁇ L tracer (about 40000 cpm) in assay buffer.
  • the filled plate is incubated for 1 hour with shaking.
  • the transfer from assay plate to filter plate is conducted.
  • the blocking buffer is aspirated by vacuum filtration and washed two times with flush buffer.
  • 90 ⁇ L is transferred from the assay plate to the filter plate.
  • the 90 ⁇ L transferred from assay plate is aspirated and washed three times with 200 ⁇ L flush buffer.
  • the plastic support is removed. It is dried for 1 hour at 60 °C. 30 ⁇ L Microscint is added. The count is performed.
  • the selectivity (IC 50 ) for human VPAC2, VPACl, and PACl is reported in Table
  • DiscoveRx CHO-PO cells are transiently transfected with rat VPACl or VPAC2 receptor DNA using commercially available transfection reagents (Lipofectamine from Invitrogen). The cells are seeded at a density of 10,000/well in a 96-well plate and are allowed to grow for 3 days in 200 mL culture medium. At day 3, the assay is performed.
  • the medium is removed. Also, the cells are washed twice. The cells are incubated in assay buffer plus IBMX for 15 minutes at room temperature. Afterwards, the stimuli are added and are dissolved in assay buffer. The stimuli are present for 30 minutes. Then, the assay buffer is gently removed. The cell lysis reagent of the DiscoveRx cAMP kit is added. Thereafter, the standard protocol for developing the cAMP signal as described by the manufacturer is used (DiscoveRx Inc., USA). EC 5 o values for cAMP generation are calculated from the raw signal or are based on absolute cAMP levels as determined by a standard curve performed on each plate. Results for each agonist are the mean of two independent runs. Rat VPACl and VPAC2 results are only generated using the DiscoveRx assay. The typically tested concentrations of peptide are: 1000, 300, 100, 10, 1, 0.3, 0.1, 0.01, 0.001, 0.0001 and O nM.
  • CHO-VPAC2 cells clone #6 (96 well ⁇ lates/50,000 cells/well and 1 day culture), PBS IX (Gibco), the peptides for the analysis in a 100 ⁇ M stock solution, rat serum from a sacrificed normal Wistar rat, aprotinin, and a DiscoveRx assay kit are obtained.
  • the rat serum is stored at 4 0 C until use and is used within two weeks.
  • two 100 ⁇ L aliquots of 10 ⁇ M peptide in rat serum are prepared by adding 10 ⁇ L peptide stock to 90 ⁇ L rat serum for each aliquot. 250 kIU aprotinin / niL is added to one of these aliquots. The aliquot is stored with aprotinin at 4°C. The aliquot is stored without aprotinin at 37°C. The aliquots are incubated overnight.
  • an incubation buffer containing PBS + 1.3 mM CaCl 2 , 1.2 mM MgCl 2 , 2 mM glucose, and 0.25 mM IBMX is prepared.
  • a plate with 11 serial 5X dilutions of peptide for the 4°C and 37°C aliquot is prepared for each peptide studied. 2000 nM is used as the maximal concentration if the peptide has an EC 50 above 1 nM and 1000 nM as maximal concentration if the peptide has an EC 5O below 1 nM from the primary screen (see Example 3).
  • the plate(s) are washed with cells twice in incubation buffer.
  • the plates are allowed to hold 50 ⁇ L incubation media per well for 15 minutes.
  • 50 ⁇ L solution per well is transferred to the cells from the plate prepared with 11 serial 5X dilutions of peptide for the 4°C and 37 0 C aliquot for each peptide studied, using the maximal concentrations that are indicated by the primary screen, in duplicate. This step dilutes the peptide concentration by a factor of two.
  • the cells are incubated at room temperature for 30 minutes. The supernatant is removed. 40 ⁇ L/well of the DiscoveRx antibody/extraction buffer is added. The cells are incubated on the shaker (300 rpm) for 1 hour. Normal procedure with the DiscoveRx kit is followed.
  • cAMP standards are included in column 12.
  • EC 50 values are determined from the cAMP assay data. The remaining amount of active peptide is estimated by the formula EC 50 , 4 c/EC 50 , 37 c-
  • Serum stability in human serum may also be determined using the above described protocol substituting rat serum for human serum (Eg. Sigma # H-4522, Lot # 043 K0500).
  • Example 7 Comparison of the interaction of the VPAC2 receptor peptide agonists of the present invention with the recombinant rat VPACl, VPAC2 and PACl receptors expressed in CHO cells:
  • the peptide samples are stored frozen and thawed prior to the assay.
  • Reference compounds e.g. VIP and the tracers
  • All peptide sample and reference compound dilutions are performed in PBS.
  • Peptides solutions are kept in the cold room for four days.
  • Stock solutions are stored at -8O 0 C. New dilution curves are prepared every week. All studies are performed on crude membranes prepared from three different cell cultures expressing the different recombinant receptors, using methodology that is known in the literature. Duplicate values are obtained for each assay.
  • VPAC2 receptor peptide agonists of the present invention are tested on the rat VPACl and VPAC2 receptors recombinantly expressed in CHO cells.
  • the compounds of the invention were evaluated in receptor binding and adenylate cyclase activation assays.
  • Dose-effect curves of adenylate cyclase activation are generated using the VPAC2 receptor peptide agonists (10 " ⁇ to 10 "6 M, two concentrations per log) of the present invention.
  • Adenylate cyclase activity is determined by the procedure of Salomon et al., a highly sensitive adenylate cyclase assay ⁇ Analytical Biochemistry 58 (1974)).
  • Membrane proteins (3-15 g) are incubated in a total volume of 60 1 containing 0.5 mM [32p]-ATP, 10 M GTP, 5 mM MgCl 2 , 0.5 mM EGTA, 1 mM cAMP, 1 mM theophylline, 10 mM phospho(enol)pyruvate, 30 g/ml pyruvate kinase and 30 mM Tris-HCl at a final pH of 7.8.
  • the reaction is initiated by membrane addition and is terminated after 15 min incubation at 37 0 C by addition of 0.5 ml of 0.5 % sodium dodecyl-sulfate solution containing 0.5 mM ATP, 0.5 mM cAMP and 20,00Og [ 3 H]-cAMP.
  • cAMP was separated from ATP by two successive chromatographies on Dowex 50Wx8 and neutral alumina.
  • Example 8 - In vivo assays Intravenous glucose tolerance test (IVGTT): Normal Wistar rats are fasted overnight and are anesthetized prior to the experiment. A blood sampling catheter is inserted into the rats. The compound is given in the jugular vein. Blood samples are taken from the carotid artery. A blood sample is drawn immediately prior to the injection of glucose along with the compound. After the initial blood sample, glucose mixed with compound is injected intravenously (i.v.). A glucose challenge of 0.5 g/kg body weight is given, injecting a total of 1.5 mL vehicle with glucose and agonist per kg body weight. The peptide concentrations are varied to produce the desired dose in ⁇ g/kg. Blood samples are drawn at 2, 4, 6 and 10 minutes after giving glucose.
  • IVGTT Intravenous glucose tolerance test
  • the control group of animals receives the same vehicle along with glucose, but with no compound added. In some instances, a 30 minute post-glucose blood sample is drawn. Aprotinin is added to the blood sample (250 kIU/ml blood). The serum is then analyzed for glucose and insulin using standard methodologies.
  • the assay uses a formulated and calibrated peptide stock in PBS. Normally, this stock is a prediluted 100 ⁇ M. stock. However, a more concentrated stock with approximately 1 mg agonist per mL is used. The specific concentration is always known. Variability in the maximal response is mostly due to variability in the vehicle dose. Protocol details are as follows:
  • Delayed IVGTT Perform IVGTT as described above, making the following changes.
  • compound or vehicle is injected i.v.
  • Glucose is injected i.v. 30 minutes later in a separate injection.
  • Blood samples are taken immediately prior to administration of the compound, at 15 minutes after administration of the compound, and at 30 minutes after administration of the compound.
  • the sample at 30 minutes after administration of the compound is taken immediately prior to glucose administration.
  • Blood samples are drawn 2, 4, 6, 10, and 30 minutes after giving glucose (i.e. 32, 34, 36, 40 and 60 minutes after compound administration).
  • the blood samples at 15 and 60 minutes are not essential to the study and not always taken.
  • Aprotinin is added to the blood sample (250 klU/ml blood).
  • the serum is then analyzed for glucose and insulin using standard methodologies.
  • the assay uses a formulated and calibrated peptide stock in PBS. Normally, this stock is a prediluted 100 ⁇ M stock. However, a more concentrated stock with approximately 1 mg agonist per mL is used. The specific concentration is always known.
  • VPAC2 receptor peptide agonist The effect of a selective VPAC2 receptor peptide agonist on plasma insulin and glucose is evaluated during OGTT in conscious Wistar rats.
  • the maximal dose of agonist is 10 ⁇ g/kg. Since the peptide is given intravenously and has a very short half-life, a delay between glucose and compound administrations is applied. Protocol details are as follows:
  • 50,000 cells / well are plated and kept in culture over night.
  • Cells are washed twice in PBS and 50 ⁇ l/well stimulation medium consisting of PBS + 1.2 MgCl 2 , 1.3 CaCl 2 , 2 glucose and 0.5 IBMX is added.
  • the plate is incubated for 15 minutes and 50 ⁇ l/well of the plasma samples is added.
  • the plate is incubated for 30 minutes, the supernatant is removed and normal procedure with the DiscoveRx assay is followed. Plates are prepared in duplicate. Protease and peptidase inhibitor are present in all plasma samples.
  • Example 10 - DPP-IV HPLC Assays P art 1: Formulation of selective VPAC2 receptor peptide agonists: Approximately 2 mg of lyophilized peptide is weighed and dissolved in approximately 1.6 mL de-ionized water. If the peptide does not dissolve, the pH is adjusted with IM NaOH to between pH 10.0 and 10.5. After incubation at room temperature for 30 minutes, l/10 th of the original volume 10 x PBS is added. The pH is adjusted to between pH 7.2 and 7.6. The peptide solution is filtered through a 0.22 ⁇ m Millex-GV syringe filter (Millipore, Bedford MA, USA). The peptide concentration is determined through absorption at 280 nm. The peptide concentration is then adjusted to 100 ⁇ M. The peptides are frozen at -20°C for further use.
  • DPP-IV Dipeptidyl-peptidase IV
  • the stability of selective VPAC2 receptor peptide agonists against proteolysis by DPP-IV is determined using 100 ⁇ L of a 100 ⁇ M peptide solution in 1 x PBS. A 10 ⁇ L solution is removed and quenched with 40 ⁇ L of 0.1% trifluoroacetic acid (TFA)/ 20% acetonitrile (ACN). This solution (20 ⁇ L) is analyzed by re versed-phase HPLC.
  • TFA trifluoroacetic acid
  • ACN acetonitrile
  • the re versed-phase analysis consists of a Zorbax 300SB-C8 column (3.5 micron, 4.6x50mm, Alltech Associates, Inc., Deerfield IL, USA) running a 15-40%B gradient over 15 minutes at 6O 0 C where A-buffer is 0.1%(v/v) TFA in water and B-buffer is 0.085%(v/v) TFA in ACN.
  • A-buffer is 0.1%(v/v) TFA in water
  • B-buffer is 0.085%(v/v) TFA in ACN.
  • the peak area is integrated. This peak area serves as an internal control as 100% intact peptide.
  • a 10 ⁇ L aliquot of a 1.12 mU/ ⁇ L solution of DPP-IV (Sigma, St. Louis, LO, USA) is added to 90 ⁇ L of a 100 ⁇ M solution of peptide, resulting in a substrate concentration of 90 ⁇ M peptide.
  • the reaction mixture is then stored at 37°C. At various time-points, 10 ⁇ L of solution is removed, quenched with 40 ⁇ L 0.1% TFA/ 20% ACN, and analyzed by reversed-phase HPLC as described above.
  • concentration (nM) is calculated using the following formula: peak area [ " time xl * initial substrate concentration ⁇ 9 nMI peak area [time 0]

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Abstract

The present invention encompasses peptides that selectively activate the VPAC2 receptor and are useful in the treatment of diabetes.

Description

SELECTIVE VPAC2 RECEPTOR PEPTIDE AGONISTS
The present invention relates to selective VPAC2 receptor peptide agonists. Type 2 diabetes, or non-insulin dependent diabetes mellitus (NIDDM), is the most common form of diabetes, affecting 90% of people with diabetes. With NTDDM, patients have impaired β-cell function resulting in insufficient insulin production and/or decreased insulin sensitivity. If NIDDM is not controlled, excess glucose accumulates in the blood, resulting in hyperglycemia. Over time, more serious complications may arise including renal dysfunction, cardiovascular problems, visual loss, lower limb ulceration, neuropathy, and ischemia. Treatments for NIDDM include improving diet, exercise, and weight control as well as using a variety of oral medications. Individuals with NTDDM can initially control their blood glucose levels by taking such oral medications. These medications, however, do not slow the progressive loss of β-cell function that occurs in NTDDM patients and, thus, are not sufficient to control blood glucose levels in the later stages of the disease. Also, treatment with currently available medications exposes NIDDM patients to potential side effects such as hypoglycemia, gastrointestinal problems, fluid retention, oedema, and/or weight gain.
Pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP) belong to the same family of peptides as secretin and glucagon. PACAP and VIP work through three G-protein-coupled receptors that exert their action through the cAMP-mediated and other Ca2+-mediated signal transduction pathways. These receptors are known as the PACAP-preferring type 1 (PACl) receptor (Isobe, et al, Regul. Pept., 110:213-217 (2003); Ogi, et al., Biochem. Biophys. Res. Commun., 196:1511-1521 (1993)) and the two VIP-shared type 2 receptors (VPACl and VPAC2) (Sherwood et al, Endocr. Rev., 21:619-670 (2000); Harnmar et al, Pharmacol Rev, 50:265-270 (1998); Couvineau, et al, J. Biol. Chem., 278:24759-24766 (2003); Sreedharan, et al., Biochem. Biophys. Res. Commun., 193:546-553 (1993); Lutz, et al, FEBS Lett., 458: 197-203 (1999); Adamou, et al., Biochem,. Biophys. Res. Commun., 209: 385-392 (1995)). A series of PACAP analogues is disclosed in US 6,242,563 and WO 2000/05260. PACAP has comparable activities towards all three receptors, whilst VIP selectively activates the two VPAC receptors (Tsutsumi et al, Diabetes, 51:1453-1460 (2002)). Both VIP (Eriksson et al, Peptides, 10: 481-484 (1989)) and PACAP (Filipsson et al, JCEM, 82:3093-3098 (1997)) have been shown to not only stimulate insulin secretion in man when given intravenously but also increase glucagon secretion and hepatic glucose output. As a consequence, PACAP or VD? stimulation generally does not result in a net improvement of glycemia. Activation of multiple receptors by PACAP or VD? also has broad physiological effects on nervous, endocrine, cardiovascular, reproductive, muscular, and immune systems (Gozes et al, Curr. Med. Chem., 6:1019- 1034 (1999)). It appears that VDMnduced watery diarrhoea in rats is mediated by only one of the VPAC receptors, VPACl (Ito et al , Peptides, 22: 1139-1151 (2001); Tsutsumi et al, Diabetes, 51:1453-1460 (2002)). The VPACl and PACl receptors are expressed on α-cells and hepatocytes and, thus, are most likely involved in the effects on hepatic glucose output.
Exendin-4 is found in the salivary excretions from the GiIa Monster, Heloderma Suspectum, (Eng et al, J.Biol.Chem., 267(11):7402-7405 (1992)). It is a 39 amino acid peptide, which has glucose dependent insulin secretagogue activity.
Recent studies have shown that peptides selective for the VPAC2 receptor are able to stimulate insulin secretion from the pancreas without gastrointestinal (GI) side effects and without enhancing glucagon release and hepatic glucose output (Tsutsumi et al , Diabetes, 51:1453-1460 (2002)). Peptides selective for the VPAC2 receptor were initially identified by modifying vasoactive intestinal peptide (VD?) and/or pituitary adenylate cyclase-activating polypeptide (PACAP). (See, for example, Xia et al, J Pharmacol Exp Ther., 281:629-633 (1997); Tsutsumi et al, Diabetes, 51:1453-1460 (2002); WO 01/23420; and WO 2004/06839.) Many of the VPAC2 receptor peptide agonists reported to date have, however, less than desirable potency, selectivity, and/or stability profiles, which could impede their clinical viability. In addition, many of these peptides are not suitable for commercial candidates as a result of stability issues associated with the polypeptides in formulation, as well as issues with the short half-life of these polypeptides in vivo. There is, therefore, a need for new therapies, which overcome the problems associated with current medications for NIDDM. The present invention seeks to provide improved compounds that are selective for the VPAC2 receptor and which induce insulin secretion from the pancreas only in the presence of high blood glucose levels. The compounds of the present invention are peptides, which are believed to also improve beta cell function. These peptides can have the physiological effect of inducing insulin secretion without GI side effects or a corresponding increase in hepatic glucose output and also generally have enhanced selectivity, potency, and/or in vivo stability of the peptide compared to known VPAC2 receptor peptide agonists.
According to a first aspect of the invention, there is provided a VPAC2 receptor peptide agonist comprising a sequence selected from: SEQ JD NO: 17 HSDA VFTEQY(OMe)TRAibRAibQLAAAibOrn Y(OMe)LQSIK
AibOrn;
SEQ ID NO: 18 HSDAVFTEK(CO(CH2)2SH)Y(OMe)TOrnLRAibQVAAAibOrn YLQSIOrnOrn;
SEQ ID NO: 19 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrnK(W) Orn;
SEQ ID NO: 20 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibK(CO(CH2)2SH)YLQ SlOrnOrn;
SEQ ID NO: 21 HSDAVFTEQY(OMe)TOrnLRAibQVAAK(CO(CH2)2SH)OrnYLQ
SlOrnOrn; SEQ ID NO: 22 HSD AVFTEQ Y(OMe)TOrnLRAibQVCAAibOrnYLQSIOrnOrn;
SEQ ID NO: 23 HSDAVFTEQY(OMe)TOrnLRCQVAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 24 HSD AVFTEQY(OMe)TOrnLRAibQLAAAibOrn YLQSIOrnOrn;
SEQ ID NO: 25 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYAibQSIOmOrn;
SEQ ID NO: 26 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQAibIOrnOrn; SEQ ID NO: 27 HSDAVFTEQY(OMe)TOmLRAibQVAAbuAibOrnYLQAibIOrnOrn;
SEQ ID NO: 28 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQAibIOrnOrn;
SEQ ID NO: 29 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQAibIOrnOrn; SEQ ID NO: 30 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYAibQSIOrnOrn; SEQ ID NO: 31 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmYLQSIOmOrn; SEQ ID NO: 32 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYAibQAibIOm
Orn; SEQ ID NO: 33 HSDAVFTEQY(OMe)TOmLRAibQLAAAibOrnYAibQSIOrnOrn; SEQ ID NO: 34 HSDAVFTEQY(OMe)TOrnLRK(W)QVAAAibOrnYLQSIOmOrn; SEQ ID NO: 35 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrn YLK(W)SIOmOm; SEQ ID NO: 36 HSDAVFTEQY(OMe)TOmLRAibQK(W)AAAibOmYLQSIOmOm; SEQ ID NO: 37 HSDAVFTEQY(OMe)TOmLRK(CO(CH2)2SH)QVAAAibOmYLQ SIOmOm:
SEQ ID NO: 38 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibK(W) YLQSIOmOm; SEQ ID NO: 39 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibCYLQSIOrnOrn; SEQ ID NO: 40 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrnOm; SEQ ID NO: 41 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLQSK(W)OmOm; SEQ ID NO: 42 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQAibIOmC
Om; SEQ ID NO: 43 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmYLQAibCOrn
Om;
SEQ ID NO: 44 HSDAVFTEQY(OMe)TOmLRAibQCAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 45 HSDAVFTEQY(OMe)TOmLRCQLAAbuAibOmYLQAibIOmOm; SEQ ID NO: 92 HSDAVFTEQY(OMe)TOmLRAibQVK(CO(CH2)2SH)AAibOrn
YLQSIOmOm;
SEQ ID NO: 93 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQSIOmCOm; SEQ ID NO: 94 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQSCOrnOrn; SEQ ID NO: 95 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibIOrn
K(CO(CH2)2SH)Om; SEQ ID NO: 96 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOm YLQSIOm
K(CO(CH2)2SH)Orn;
SEQ ID NO: 97 HSDAVFTEQY(OMe)TOrnLRK(W)QLAAbuAibOrnYLQAibIOrn Om;
SEQ ID NO: 98 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQSIOrnOrnC; SEQ ID NO: 99 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrnOrnC; SEQ ID NO: 100 HSDA VFTEQ Y(OMe)TOmLRAibQLAAbuAibOmYLQSIOrnOrnC; SEQ ID NO: 101 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQAibI
OmOm;
SEQ ID NO: 102 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrn Y(OMe)LQAM OrnCOrn;
SEQ ID NO: 103 HSDAVFTEQY(OMe)TOmLRAibQCAAbuAibOmY(OMe)LQAibI
OmOm; SEQ DD NO: 104 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQAibIOm
OmC; SEQ ID NO: 105 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmY(OMe)LQSI
OmOm; SEQ ID NO: 106 HSDAVFTEQY(OMe)TOmLRAibQCAAbuAibOmY(OMe)LQSI
OmOm;
SEQ ID NO: 107 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmY(OMe)LQSI OmCOm;
SEQ ID NO: 108 HSDAVFTEQY(OMe)TOrnLRAibQLAbuAAibOrn YLQSIOmOm; SEQ ID NO: 109 HSDAVFTEQY(OMe)TOmLRAibQK(CO(CH2)2SH)AAbu
AibOm YLQ AibIOrnOrn ;
SEQ ID NO: 110 HSDAVFTEQY(OMe)TOmLRAibQK(W)AAbuAibOmYLQ AiblOrnOrn;
SEQ ID NO: 145 HSDAVFTDNYTRLRKQVAAKKYLQSIKNKRQ; SEQ ID NO: 146 HSDAVFTDNYTLLRAibQVAAAibKYLQSIOrnNOrn; SEQ ID NO: 147 HSDAVFTDNYTQLRAibQVAAAibKYLQSIOrnNOrn; SEQ ID NO: 148 HSDAVFTDNYTFLRAibQVAAAibKYLQSIOmNOm; SEQ ID NO: 149 HSDAVFTDNYTOmLRAibQVAAAibKYLQCIOrnNOrn; SEQ ID NO: 150 HSDAVFTDNYTOmLRAibQVAACOrnYLQSIOrnNOrn; SEQ ID NO: 151 HSDAVFTDNYTOmLRAibQVAAAibKYLQSSOmNOm; SEQ ID NO: 152 HSD AVFTDNYTOmLR AibQ V A AAibKYLS SIOmNOm; SEQ ID NO: 153 HSDAVFTDNYTOrnLRAibQVAAAibKYSQSIOrnNOrn; SEQ ID NO: 154 HSDAVFTDNYTOrnLRAibQVAAAibKSLQSIOrnNOrn; SEQ ID NO: 155 HSDAVFTDNYTOrnLRAibQVAAAibSYLQSIOrnNOrn; SEQ ID NO: 156 HSDAVFTDNYTOrnLRAibQVSAAibKYLQSIOrnNOrn; SEQ ID NO: 157 HSDAVFTDNYTOrnLRAibQSAAAibKYLQSIOrnNOrn;
SEQ ID NO: 158 HSDAVFTDNYTOrnLRAibSVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 159 HSDAVFTDNYTOmSRAibQVAAAibKYLQSIOmNOrn;
SEQ ID NO: 160 HSDAVFTDSYTOmLRAibQVAAAibKYLQSIOrnNOrn; SEQ ID NO: 161 HSD AVFTDN YThRLR AibQV A A AibKYLQS IKNKRY;
SEQ ID NO: 162 HSDAVFTDNYTRLRAibQVAAAibKYLQSIKAibOrn;
SEQ ID NO: 163 HSDAVFTDNY(OMe)TRLRAibQVAAAibKYLQSIKNKRY;
SEQ ID NO: 164 HSEAVFTENYTOrnLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 165 HSDAVFTDQYTOmLRAibQVAAAibKYLQSIOrnQOrn; SEQ ID NO: 166 HSDAVFTDNYTRLLAKLALQKYLQSIOrnNOrn;
SEQ ID NO: 167 HSDAVFTDNYTOrnLLAKLALQKYLQSIOmNOrn;
SEQ ID NO: 168 HSEAVFTEQYTOrnLRAibQVAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 169 HSDAVFTDNYTOrnLRAibQVASAibKYLQSIOmNOrn;
SEQ ID NO: 170 HSEAVFTEQY(OMe)TOrnLRAibQLAAAibOmYLQSIOrnOm; SEQ ID NO: 171 HSDAVFTDQY(OMe)TOrnLRAibQLAAAibOmYLQSIOmOrn;
SEQ lD NO: 172 HSD AVFTDQYTOrnLRAibQLAAAibOrn YLQSIOmOm;
SEQ ID NO: 173 HSDAVFTDQYTOmLRAibQVAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 174 HSD A VFTDNYTOrnLRAibQVAAAibOrn YLQSIOmOm;
SEQ ID NO: 175 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOmOm; SEQ ID NO: 176 HSDAVFTDNYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ ID NO: 177 HSDAVFTDQYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ E) NO: 178 HSDAVFTDQYTRAibRAibQLAAAibKYLQSIKAibK;
SEQ ID NO: 179 HSDAVFTDQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK;
SEQ ID NO: 180 HSEAVFTEQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK; SEQ ID NO: 181 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLCSIOmOrn;
SEQ ID NO: 182 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYL K(CO(CH2)2SH)SIOrnOrn;
SEQ ID NO: 183 HSDAVFTEQY(OMe)TOmLRAibQVACAibOrnYLQSIOrnOrn;
SEQ ID NO: 184 HSDAVFTEQY(OMe)TOmLRAibQVAK(CO(CH2)2SH)AibOm YLQSIOmOrn;
SEQ ID NO: 185 HSDAVFTEQY(OMe)TOrnLRAibCVAAAibOrn YLQSIOmOm;
SEQ ID NO: 186 HSD AVFTDNYTOmLRK(W)Q VA A AibK YLQSIOmNOm; SEQ E) NO: 187 HSD AVFTEQY(OMe)TOrnLRAibQLAAAibOrn Y(OMe)LQ
SIOmOm;
SEQ ID NO: 188 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSCOrnOrn; SEQ ID NO: 189 HSDA VFTEQ Y(OMe)TOrnLRAibQCAAAibOrnYLQSIOrnOm; SEQ ID NO: 190 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOmCOrn; SEQ ID NO: 191 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQCIOrnOrn; SEQ ID NO: 192 HSDAVFTECY(OMe)TOrnLRAibQVAAAibOmYLQSIOrnOrn; SEQ ID NO: 193 HSDAVFTEQY(OMe)TOrnCRAibQVAAAibOrnYLQSIOrnOm; SEQ ID NO: 194 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQS K(CO(CH2)2SH)OrnOrn;
SEQ ID NO: 195 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQ
K(CO(CH2)2SH)IOrnOrn; SEQ ID NO: 196 HSDAVFTEQY(OMe)TOmLRAibQK(CO(CH2)2SH)AAAibOrnYL
QSIOrnOrn; SEQ ID NO: 197 HSDAVFTEQY(OMe)TOrnLRAibK(CO(CH2)2SH)VAAAibOmY
LQSIOrnOrn; SEQ ID NO: 198 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrn
K(CO(CH2)2SH)Orn; and
SEQ ID NO: 199 HSDAVFTEQY(OMe)TOrnK(CO(CH2)2SH)RAibQVAAAibOrn YLQSIOrnOrn;
and a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide sequence and wherein the C-terminal extension comprises an amino acid sequence of the formula: Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaa10-Xaa1i-Xaa12
Formula 3 (SEQ ID NO: 3) wherein:
Xaa] is: GIy, Cys, or absent;
Xaa2 is: GIy, Arg, or absent; Xaa3 is: Pro, Thr, or absent;
Xaa*. is: Ser, or absent;
Xaas is: Ser, or absent; Xaa6 is: GIy, or absent;
Xaa7 is: Ala, or absent;
Xaa8 is: Pro, or absent;
Xaa9 is: Pro, or absent;
Xaa10 is: Pro, or absent;
Xaaπ is: Ser, Cys, or absent; and
Xaa12 is: Cys, or absent; wherein at least five of Xaai to Xaa12 of the C-terminal extension are present and wherein if Xaa1; Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9, Xaa10, or Xaaπ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
Preferably, at least six of Xaai to Xaa^ of the C-terminal extension of Formula 3 are present. More preferably, at least seven, eight, nine, ten, eleven, or all of Xaa1 to Xaa12 of the C-terminal extension are present.
More preferably, the C-terminal extension of the VPAC2 receptor peptide agonist is selected from:
Figure imgf000009_0001
The VPAC2 receptor peptide agonist sequence may further comprise a histidine residue at the N-terminus of the peptide.
Preferably, the VPAC2 receptor peptide agonist according to the first aspect of the present invention further comprises a N-terminal modification at the N-terminus of the peptide agonist wherein the N-terminal modification is selected from: (a) addition of D-histidine, isoleucine, methionine, or norleucine; (b) addition of a peptide comprising the sequence Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys- Arg (SEQ ID NO: 91) wherein the Arg is linked to the N-terminus of the peptide agonist;
(c) addition of C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3;
(d) addition of -C(O)R1 wherein R1 is a C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, Ci-C6 alkoxy, -NH2, -OH, halogen, -SH and -CF3; a aryl or aryl C1-C4 alkyl optionally substituted with one or more substituents independently selected from C1-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, Ci-C6 alkoxy, -NH2, -OH, halogen and -CF3; -NR2R3 wherein R2 and R3 are independently hydrogen, C1-C6 alkyl, aryl or aryl Ci-C4 alkyl; -OR4 wherein R4 is C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, Ci-C6 alkoxy, -NH2, -OH, halogen and -CF3, aryl or aryl Ci-C4 alkyl optionally substituted with one or more substituents independently selected from Ci-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, Ci-C6 alkoxy, -NH2, -OH, halogen and -CF3; or 5-ρyrrolidin-2-one;
(e) addition Of -SO2R5 wherein R5 is aryl, aryl Ci-C4 alkyl or Ci-C16 alkyl;
(f) formation of a succinimide group optionally substituted with C1-C 6 alkyl or -SR6, wherein R6 is hydrogen or Ci-C 6 alkyl; (g) addition of methionine sulfoxide;
(h) addition of biotinyl-6-aminohexanoic acid (6-aminocaproic acid); and (i) addition of -C(=NH)-NH2.
Preferably, the N-terminal modification is the addition of a group selected from: acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3- phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3- mercaptopropionyl, biotinyl-6-aminohexanoic acid (6-aminocaproic acid), and -C(=NH)- NH2. It is especially preferred that the N-terminal modification is the addition of acetyl or hexanoyl.
It will be appreciated by the person skilled in the art that VPAC2 receptor peptide agonists comprising various combinations of peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199, C-terminal extensions and N-terminal modifications as described herein, may be made based on the above disclosure. It is preferred that the VPAC2 receptor peptide agonist according to the first aspect of the present invention comprises an amino acid sequence selected from:
Figure imgf000011_0001
Figure imgf000012_0001
Figure imgf000013_0001
Figure imgf000014_0001
Figure imgf000015_0001
Figure imgf000016_0001
Figure imgf000017_0001
Figure imgf000018_0001
It is more preferred that the VPAC2 receptor peptide agonist according to the first aspect of the present invention comprises an amino acid sequence selected from:
Figure imgf000019_0001
According to a second aspect of the present invention, there is provided a VPAC2 receptor peptide agonist comprising an amino acid sequence of the formula: Xaa! -Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Thr-Xaas-Xaa9-Xaai o-Thr-Xaai 2-Xaa13- Xaa! 4- Xaais-Xaa^-Xaaπ-Xaaig -Abu-Xaa2o-Xaa21-Xaa22- Xaa23-Xaa24-Xaa25-Xaa26- Xaa27-Xaa28-Xaa29-Xaa3o-Xaa31-Xaa32-Xaa33-Xaa34-Xaa35-Xaa36-Xaa37-Xaa38- Xaa3g-Xaa4o Formula 4 (SEQ E) NO: 4) wherein:
Xaaϊ is: His, dH, or is absent;
Xaa2 is: dA, Ser, VaI, GIy, Thr, Leu, dS, Pro, or Aib;
Xaa3 is: Asp or GIu; Xaa4 is: Ala, De, Tyr, Phe, VaI, Thr, Leu, Trp, GIy, dA, Aib, or NMeA;
Xaa5 is: VaI, Leu, Phe, He, Thr, Trp, Tyr, dV, Aib, or NMeV;
Xaa6 is: Phe, lie, Leu, Thr, VaI, Trp, or Tyr;
Xaag is: Asp, GIu, Ala, Lys, Leu, Arg, or Tyr;
Xaa9 is: Asn, GIn, Asp, GIu, Ser, Cys, Lys, or K(CO(CH2)2SH); Xaa10 is: Tyr, Trp, Tyr(OMe), Ser, Cys, or Lys;
Xaa12 is: Arg, Lys, GIu, hR, Orn, Lys (isopropyl), Aib, Cit, Ala, Leu, GIn, Phe, Ser, or
Cys;
Xaa13 is: Leu, Phe, GIu, Ala, Aib, Ser, Cys, Lys, or K(CO(CH2)2SH);
Xaa14 is: Arg, Leu, Lys, Ala, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, Cit, Ser, or Cys; Xaa15 is: Lys, Ala, Arg, GIu, Leu, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, K(Ac), Cit,
Ser, Cys, K(W), or K(CO(CH2)2SH);
Xaa16 is: GIn, Lys, GIu, Ala, hR, Orn, Lys (isopropyl), Cit, Ser, Cys, K(CO(CH2)2SH), or
K(W);
Xaa17 is: VaI, Ala, Leu, lie, Met, NIe, Lys, Aib, Ser, Cys, K(CO(CH2)2SH), or K(W); Xaa18 is: Ala, Ser, Cys, Lys, K(CO(CH2)2SH), K(W), Abu, or NIe;
Xaa20 is: Lys, GIn, hR, Arg, Ser, His, Orn, Lys (isopropyl), Ala, Aib, Trp, Thr, Leu, He,
Phe, Tyr, VaI, K(Ac), Cit, Cys, K(CO(CH2)2SH), or K(W);
Xaa21 is: Lys, His, Arg, Ala, Phe, Aib, Leu, GIn, Orn, hR, K(Ac), Cit, Ser, Cys, VaI, Tyr,
He, Thr, Trp, K(W), or K(CO(CH2)2SH); Xaa22 is: Tyr, Trp, Phe, Thr, Leu, He, VaI, Tyr(OMe), Ala, Aib, Ser, Cys, Lys, K(W), or
K(CO(CH2)2SH);
Xaa23 is: Leu, Phe, He, Ala, Trp, Thr, VaI, Aib, Ser, Cys, Lys, K(W), or K(CO(CH2)2SH); Xaa24 is: GIn, GIu, Asn, Ser, Cys, Lys, K(CO(CH2)2SH), or K(W);
Xaa25 is: Ser, Asp, Phe, He, Leu, Thr, VaI, Trp, GIn, Asn, Tyr, Aib, GIu, Cys, Lys,
K(CO(CH2)2SH), or K(W);
Xaa26 is: He, Leu, Thr, VaI, Trp, Tyr, Phe, Aib, Ser, Cys, Lys, K(CO(CH2)2SH), or K(W); Xaa27 is: Lys, hR, Arg, GIn, Ala, Asp, GIu, Phe, GIy, His, He, Met, Asn, Pro, Ser, Thr,
VaI, Trp, Tyr, Lys (isopropyl), Cys, Leu, Orn, dK, K(W), or K(CO(CH2)2SH);
Xaa28 is: Asn, Asp, GIn, Lys, Arg, Aib, Orn, hR, Cit, Pro, dK, Ser, Cys, K(CO(CH2)2SH), or K(W);
Xaa29 is: Lys, Ser, Arg, Asn, hR, Ala, Asp, GIu, Phe, GIy, His, He, Leu, Met, Pro, GIn, Thr, VaI, Trp, Tyr, Cys, Orn, Cit, Aib, K(W), K(CO(CH2)2SH), or is absent;
Xaa30 is: Arg, Lys, He, Ala, Asp, GIu, Phe, GIy, His, Leu, Met, Asn, Pro, GIn, Ser, Thr,
VaI, Trp, Tyr, Cys, hR, Cit, Aib, Orn, K(W), K(CO(CH2)2SH), or is absent;
Xaa3i is: Tyr, His, Phe, Thr, Cys, Ser, Lys, GIn, K(W), K(CO(CH2)2SH), or is absent;
Xaa32 is: Ser, Cys, Lys, or is absent; Xaa33 is: Trp or is absent;
Xaa34 is: Cys or is absent;
Xaa35 is: GIu or is absent;
Xaa36 is: Pro or is absent;
Xaa37 is: GIy or is absent; Xaa38 is: Trp or is absent;
Xaa3g is: Cys or is absent; and
Xaa40 is: Arg or is absent wherein if Xaa29, Xaa30, Xaa31, Xaa32, Xaa33, Xaa34, Xaa35, Xaa36, Xaa37, Xaa38, or Xaa39 is absent, the next amino acid present downstream is the next amino acid in the peptide agonist sequence, and a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide of Formula 4 and wherein the C-terminal extension comprises an amino acid sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaa1o-Xaa11-Xaai2
Formula 3 (SEQ ID NO: 3) wherein: Xaai is: GIy, Cys, or absent;
Xaa2 is: GIy, Arg, or absent;
Xaa3 is: Pro, Thr, or absent;
Xaa4 is: Ser, or absent; Xaa5 is: Ser, or absent;
Xaa6 is: GIy, or absent;
Xaa7 is: Ala, or absent;
Xaa8 is: Pro, or absent;
Xaa9 is: Pro, or absent; Xaa10 is: Pro, or absent;
Xaaπ is: Ser, Cys, or absent; and
Xaa12 is: Cys, or absent; wherein at least five of Xaai to Xaa12 of the C-terminal extension are present and wherein if Xaal5 Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9, Xaa10, or Xaaπ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
Preferably, at least six of Xaai to Xaa12 of the C-terminal extension of Formula 3 is present. More preferably, seven, eight, nine, ten, eleven, or all of Xaa] to Xaa12 of the
C-terminal extension are present. Preferably, the C-terminal extension of the VPAC2 receptor peptide agonist according to the second aspect of the present invention is selected from:
Figure imgf000022_0001
An alternative C-terminal extension according to the second aspect of the present invention may comprise an amino acid sequence of the formula: Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaa10
Formula 13 (SEQ ID NO: 13) wherein:
Xaaj is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa2 is: Arg, Ser, hR, Om, His, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa3 is: Thr, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa4 is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa5 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CEb)2SH), or absent; Xaa6 is: Pro, Ser, Ala, Arg, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa7 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa8 is: Lys, K(W), Pro, Cys, K(CO(CH2)2SH), or absent; Xaa9 is: K(E-C16), Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; and Xaa10 is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent.
It is preferred that if Xaa1; Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8 or Xaag of Formula 13 is absent, the next amino acid downstream is the next amino acid in the C- terminal extension. The C-terminal amino acid may be amidated.
Preferably, at least one of Xaai to Xaa^ of the C-terminal extension of Formula 13 is present. More preferably, at least two, three, four, five, six, seven, eight, nine or all of Xaai to Xaa10 of the C-terminal extension are present. More preferably the alternative C-terminal extension of the VPAC2 receptor peptide agonist is selected from:
Figure imgf000023_0001
Preferably, the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 (SEQ DD NO: 4) wherein Xaa3 is Asp or GIu, Xaa8 is Asp or GIu, Xaa9 is Asn or GIn, Xaa10 is Tyr or Tyr(OMe), Xaaπ is Arg, hR, Lys, or Orn, Xaa14 is Arg, GIn, Aib, hR, Orn, Cit, Lys, Ala, or Leu, Xaa15 is Lys, Aib, Orn, or Arg, Xaa16 is GIn or Lys, Xaa17 is VaI, Leu, Ala, He, Lys, or NIe, Xaa20 is Lys, VaI, Leu, Aib, Ala, GIn, or Arg, Xaa21 is Lys, Aib, Orn, Ala, GIn, or Arg, Xaa23 is Leu or Aib, Xaa25 is Ser or Aib, Xaa27 is Lys, Orn, hR, or Arg, Xaa2g is Asn, GIn, Lys, hR, Aib, Orn, or Pro and Xaa29 is Lys, Om, hR, or is absent.
Preferably, the VPAC2 receptor peptide according to the second aspect of the present invention comprises a sequence of the Formula 4 (SEQ ID NO: 4) wherein either Xaa23 or Xaa25 is Aib. Even more preferably, Xaa23 and Xaa25 are both Aib. Preferably, the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein either Xaa14 or Xaa15 is Aib.
Alternatively, the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein either Xaa20 or Xaa21 is Aib.
More preferably, either Xaa14 or Xaa^ is Aib and either Xaa2o or Xaa21 is Aib. It is especially preferred that Xaa15 is Aib and Xaa2o is Aib.
Preferably, the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises a sequence of the Formula 4 wherein Xaais is Aib, Xaa2o is Aib, and Xaa12, Xaa21, Xaa27 and Xaa28 are all Orn. More preferably, Xaa15 is Aib, Xaa20 is Aib, Xaa12, Xaa21, Xaa27 and Xaa28 are all Orn, Xaa8 is GIu, Xaa9 is GIn and Xaa10 is Tyr(OMe). Even more preferably, Xaa15 is Aib, Xaa2o is Aib, Xaa12, Xaa21, Xaa27 and Xaa28 are all Orn, Xaag is GIu, Xaa9 is GIn, Xaaio is Tyr(OMe), and Xaa23 and/or Xaa25 is Aib. Preferably, the VPAC2 receptor peptide agonist according to the second aspect of the present invention further comprises a N-terminal modification at the N-terminus of the peptide agonist wherein the N-terrninal modification is selected from:
(a) addition of D-histidine, isoleucine, methionine, or norleucine;
(b) addition of a peptide comprising the sequence Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys- Arg (SEQ ID NO: 91) wherein the Arg is linked to the N-terminus of the peptide agonist; (c) addition of C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3;
(d) addition Of -C(O)R1 wherein R1 is a C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen, -SH and -CF3; an aryl optionally substituted with one or more substituents independently selected from C1-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; an aryl C1-C4 alkyl optionally substituted with one or more substituents independently selected from C1-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; -NR2R3 wherein R2 and R3 are independently hydrogen, C1-C6 alkyl, aryl or aryl C1-C4 alkyl; -OR4 wherein R4 is C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3, aryl optionally substituted with one or more substituents independently selected from C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3, or aryl C1-C4 alkyl optionally substituted with one or more substituents independently selected from C1-C β alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; or 5- pyrrolidin-2-one;
(e) addition Of -SO2R5 wherein R5 is aryl, aryl C1-C4 alkyl or C1-C16 alkyl; (f) formation of a succinimide group optionally substituted with C1-C 6 alkyl or -SR6, wherein R5 is hydrogen or C1-C 6 alkyl; (g) addition of methionine sulfoxide;
(h) addition of biotinyl-6-aminohexanoic acid (6-aminocaproic acid); and (i) addition of -C(=NH)-NH2. Preferably, the N-terminal modification is the addition of a group selected from: acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3- phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3- mercaptopropionyl, biotinyl-6-aminohexanoic acid (6-aminocaproic acid), and -C(=NH)- NH2. It is especially preferred that the N-terminal modification is the addition of acetyl or hexanoyl.
It will be appreciated by the person skilled in the art that VPAC2 receptor peptide agonists comprising various combinations of peptide sequence according to Formula 4, C-terminal extensions and N-terminal modifications as described herein, may be made based on the above disclosure.
It is preferred that the VPAC2 receptor peptide agonist according to the second aspect of the present invention comprises an amino acid sequence selected from:
Figure imgf000026_0001
Figure imgf000027_0001
Figure imgf000028_0001
According to a third aspect of the present invention, there is provided a pharmaceutical composition comprising a VPAC2 receptor peptide agonist of the present invention and one or more pharmaceutically acceptable diluents, carriers and excipients. According to a fourth aspect of the present invention, there is provided a VPAC2 receptor peptide agonist of the present invention for use as a medicament.
According to a fifth aspect of the present invention, there is provided the use of a VPAC2 receptor peptide agonist of the present invention for the manufacture of a medicament for the treatment of non-insulin-dependent diabetes. According to a further aspect of the present invention, there is provided the use of a VPAC2 receptor peptide agonist of the present invention for the manufacture of a medicament for the treatment of insulin-dependent diabetes.
The present invention provides a method of treating diabetes in a patient in need thereof comprising administering a VPAC2 receptor peptide agonist of the present invention, wherein the diabetes may be non-insulin dependent diabetes or may be insulin- dependent diabetes.
The present invention further provides a pharmaceutical composition containing a VPAC2 receptor peptide agonist of the present invention for treating non-insulin dependent diabetes or insulin-dependent diabetes. According to an alternative embodiment of the present invention, there is provided a VPAC2 receptor peptide agonist comprising a sequence selected from: SEQ ID NO: 17 HSDAVFTEQY(OMe)TRAibRAibQLAAAibOrn Y(OMe)LQSIK AibOrn; SEQ ID NO: 18 HSDAVFTEK(CO(CH2)2SH)Y(OMe)TOraLRAibQVAAAibOrn
YLQSIOrnOrn;
SEQ ID NO: 19 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrnK(W) Om;
SEQ ID NO: 20 HSDAVFTEQY(OMe)TOmLRAibQVAAAibK(CO(CH2)2SH)YLQ
SIOmOm; SEQ ID NO: 21 HSDAVFTEQY(OMe)TOrnLRAibQVAAK(CO(CH2)2SH)OmYLQ
SIOmOm; SEQ ID NO: 22 HSDA VFTEQY(OMe)TOrnLRAibQVCAAibOrn YLQSIOrnOrn; SEQ ID NO: 23 HSDAVFTEQY(OMe)TOmLRCQV AAAibOrnYLQSIOrnOrn; SEQ ID NO: 24 HSDA VFTEQ Y(OMe)TOrnLRAibQLAAAibOrnYLQSIOrnOrn; SEQ ID NO: 25 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOmYAibQSIOmOm; SEQ ID NO: 26 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLQAibIOrnOrn; SEQ ID NO: 27 HSDAVFTEQY(OMe)TOrnLRAibQVAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 28 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQAibIOrnOrn; SEQ ID NO: 29 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQAibIOrnOrn; SEQ ID NO: 30 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYAibQSIOrnOrn; SEQ ID NO: 31 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQSIOrnOrn; SEQ ID NO: 32 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYAibQAibIOrn
Om;
SEQ ID NO: 33 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQSIOrnOrn; SEQ ID NO: 34 HSDA VFTEQY(OMe)TOmLRK(W)Q VAAAibOrnYLQSIOrnOrn; SEQ ID NO: 35 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLK(W)SIOmOm; SEQ ID NO: 36 HSDAVFTEQY(OMe)TOmLRAibQK(W)AAAibOrnYLQSIOrnOrn; SEQ ID NO: 37 HSDA VFTEQY(OMe)TOrnLRK(CO(CH2)2SH)QVAAAibOrn YLQ
SIOmOm:
SEQ ID NO: 38 HSDAVFTEQY(OMe)TOmLRAibQVAAAibK(W) YLQSIOmOm; SEQ ID NO: 39 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibCYLQSIOrnOrn; SEQ ID NO: 40 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 41 HSDA VFTEQY(OMe)TOrnLRAibQVAAAibOrn YLQSK(W)OmOm; SEQ ID NO: 42 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrnC Orn; SEQ ID NO: 43 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibCOrn
Orn;
SEQ ID NO: 44 HSDAVFTEQY(OMe)TOrnLRAibQCAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 45 HSDAVFTEQY(OMe)TOrnLRCQLAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 92 HSDAVFTEQY(OMe)TOrnLRAibQVK(CO(CH2)2SH)AAibOrn
YLQSIOrnOrn;
SEQ ID NO: 93 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmYLQSIOrnCOrn; SEQ ID NO: 94 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQSCOrnOrn; SEQ TD NO: 95 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOraYLQAibIOrn
K(CO(CH2)2SH)Orn; SEQ ID NO: 96 HSD AVFTEQ Y(OMe)TOrnLRAibQLAAbuAibOrnYLQSIOrn
K(CO(CHa)2SH)Qm;
SEQ ID NO: 97 HSDAVFTEQY(OMe)TOmLRK(W)QLAAbuAibOrnYLQAibIOrn Orn;
SEQ ID NO: 98 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOmYLQSIOrnOrnC; SEQ ID NO: 99 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOrnOrnC; SEQ ID NO: 100 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQSIOrnOrnC; SEQ ID NO: 101 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmY(OMe)LQAibI OrnOrn;
SEQ ID NO: 102 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQAibI
OrnCOrn; SEQ ID NO: 103 HSDAVFTEQY(OMe)TOrnLRAibQCAAbuAibOrnY(OMe)LQAibI
OrnOrn; SEQ ID NO: 104 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibIOrn
OmC; SEQ ID NO: 105 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOmY(OMe)LQSI
OrnOrn;
SEQ ID NO: 106 HSD A VFTEQY(OMe)TOrnLRAibQCAAbuAibOrn Y(OMe)LQSI OrnOrn;
SEQ TD NO: 107 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQSI OrnCOrn; SEQ ID NO: 108 HSDAVFTEQY(OMe)TOmLRAibQLAbuAAibOrnYLQSIOrnOrn;
SEQ ID NO: 109 HSDAVFTEQY(OMe)TOrnLRAibQK(CO(CH2)2SH)AAbu AibOmYLQAiblOrnOrn;
SEQ ID NO: 110 HSD AVFTEQ Y(OMe)TOrnLRAibQK(W)AAbuAibOmYLQ AiblOmOrn;
SEQ ID NO: 145 HSDAVFTDNYTRLRKQVAAKKYLQSIKNKRQ;
SEQ ID NO: 146 HSDAVFTDNYTLLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 147 HSDAVFTDNYTQLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 148 HSDAVFTDNYTFLRAibQVAAAibKYLQSIOmNOrn; SEQ ID NO: 149 HSDAVFTDNYTOmLRAibQVAAAibKYLQCIOrnNOrn;
SEQ ID NO: 150 HSDAVFTDNYTOrnLRAibQVAACOmYLQSIOmNOrn;
SEQ ID NO: 151 HSDAVFTDNYTOrnLRAibQVAAAibKYLQSSOmNOm;
SEQ ID NO: 152 HSDAVFTDNYTOrnLRAibQVAAAibKYLSSIOmNOrn;
SEQ ID NO: 153 HSDAVFTDNYTOrnLRAibQVAAAibKYSQSIOrnNOrn; SEQ ID NO: 154 HSDAVFTDNYTOrnLRAibQVAAAibKSLQSIOrnNOrn;
SEQ ID NO: 155 HSDAVFTDNYTOrnLRAibQVAAAibSYLQSIOrnNOrn;
SEQ ID NO: 156 HSDAVFTDNYTOmLRAibQVSAAibKYLQSIOrnNOrn;
SEQ ID NO: 157 HSDAVFTDNYTOmLRAibQSAAAibKYLQSIOrnNOπi;
SEQ ID NO: 158 HSDAVFTDNYTOmLRAibSVAAAibKYLQSIOrnNOrn; SEQ ID NO: 159 HSDAVFTDNYTOrnSRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 160 HSDAVFTDSYTOrnLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 161 HSDAVFTDNYThRLRAibQVAAAibKYLQSIKNKRY;
SEQ ID NO: 162 HSDAVFTDNYTRLRAibQVAAAibKYLQSIKAibOrn;
SEQ ID NO: 163 HSDAVFTDNY(OMe)TRLRAibQVAAAibKYLQSIKNKRY; SEQ ID NO: 164 HSEAVFTENYTOrnLRAibQVAAAibKYLQSIOmNOrn;
SEQ ID NO: 165 HSDAVFTDQYTOrnLRAibQVAAAibKYLQSIOmQOrn;
SEQ ID NO: 166 HSDAVFTDNYTRLLAKLALQKYLQSIOrnNOrn;
SEQ ID NO: 167 HSDAVFTDNYTOrnLLAKLALQKYLQSIOmNOrn;
SEQ ID NO: 168 HSEAVFTEQ YTOrnLRAibQVAAAibOrnYLQSIOrnOrn; SEQ ID NO: 169 HSDAVFTDNYTOrnLRAibQVASAibKYLQSIOmNOm;
SEQ ID NO: 170 HSEA VFTEQ Y(OMe)TOrnLRAibQLAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 171 HSDAVFTDQY(OMe)TOmLRAibQLAAAibOrnYLQSIOrnOrn; SEQ ID NO: 172 HSDA VFTDQYTOrnLRAibQLAAAibOrn YLQSIOrnOrn;
SEQ ID NO: 173 HSDAVFTDQYTOmLRAibQVAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 174 HSDAVFTDNYTOrnLRAibQVAAAibOmYLQSIOrnOrn;
SEQ ID NO: 175 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOrnOrn; SEQ ID NO: 176 HSDAVFTDNYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ ID NO: 177 HSDAVFTDQYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ ID NO: 178 HSDAVFTDQYTRAibRAibQLAAAibKYLQSIKAibK;
SEQ ID NO: 179 HSDAVFTDQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK;
SEQ ID NO: 180 HSEAVFTEQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK; SEQ ID NO: 181 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLCSIOrnOrn;
SEQ ID NO: 182 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYL K(CO(CH2)2SH)SIOmOrn;
SEQ ID NO: 183 HSDAVFTEQY(OMe)TOrnLRAibQVACAibOrnYLQSIOmOrn;
SEQ ID NO: 184 HSDAVFTEQY(OMe)TOrnLRAibQVAK(CO(CH2)2SH)AibOrn YLQSIOrnOrn;
SEQ ID NO: 185 HSDAVFTEQY(OMe)TOrnLRAibCVAAAibOmYLQSIOmOrn;
SEQ ID NO: 186 HSDAVFTDNYTOrnLRK(W)QVAAAibKYLQSIOmNOrn;
SEQ ID NO: 187 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrn Y(OMe)LQ
SlOrnOrn; SEQ ID NO: 188 HSDAVFTEQY(OMe)TOmLRAIbQV AAAibOrnYLQSCOrnOrn;
SEQ ID NO: 189 HSDA VFTEQ Y(OMe)TOrnLRAibQCAAAibOrn YLQSIOrnOrn;
SEQ ID NO: 190 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrnCOrn;
SEQ ID NO: 191 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQCIOrnOrn;
SEQ ID NO: 192 HSDA VFTECY(OMe)TOrnLRAibQVAAAibOrn YLQSIOrnOrn; SEQ ID NO: 193 HSDAVFTEQY(OMe)TOrnCRAibQVAAAibOrnYLQSIOmOrn;
SEQ ID NO: 194 HSDA VFTEQY(OMe)TOrnLRAibQVAAAibOrn YLQS K(C0(CH2)2SH)0rn0rn;
SEQ ID NO: 195 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQ
K(CO(CH2)2SH)IOrnOrn; SEQ ID NO: 196 HSDAVFTEQY(OMe)TOrnLRAibQK(CO(CH2)2SH)AAAibOrnYL
QSIOrnOrn;
SEQ ID NO: 197 HSDAVFTEQY(OMe)TOrnLRAibK(CO(CH2)2SH)VAAAibOrnY LQSIOmOrn; SEQ ID NO: 198 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQSIOrn
K(CO(CH2)2SH)Orn; and
SEQ ID NO: 199 HSD AVFTEQ Y(OMe)TOrnK(CO(CH2)2SH)RAibQVAAAibOrn YLQSIOrnOrn.
Preferably, the VPAC2 receptor peptide agonist of the above alternative embodiment further comprises a C-terminal extension, wherein the N-terminus of the C- terminal extension is linked to the C-terminus of the peptide sequence and wherein the C- terminal extension comprises an amino acid sequence of the formula: Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-XaacrXaa1o-Xaa11-Xaa12-
Xaa13
Formula 1 (SEQ ID NO: 1) wherein:
Xaaj is: GIy, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa2 is: GIy, Arg, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa3 is: Pro, Thr, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa4 is: Ser, Pro, His, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa5 is: Ser, Arg, Thr, Trp, Lys, Cys, K(W), K(CO(CH2)2SH), or absent; Xaa6 is: GIy, Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa7 is: Ala, Asp, Arg, GIu, Lys, GIy, Cys, K(W), K(CO(CH2)2SH), or absent; Xaa8 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa9 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa10 is: Pro, Ser, Ala, Arg, Lys, His, Cys, K(W), K(CO(CH2)2SH), or absent; Xaaπ is: Ser, Cys, His, Pro, Lys, Arg, K(W), K(CO(CH2)2SH), or absent; Xaa12 is: His, Ser, Arg, Lys, Cys, K(W), K(CO(CH2)2SH), or absent; and Xaa13 is: His, Ser, Arg, Lys, Cys, K(W), K(CO(CH2)2SH), or absent; provided that if Xaa1 ; Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9, Xaa10, Xaaπ, or Xaa12 is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated. It is preferable that the C-terminal extension of formula 1 has no more than three of any one of the following; Cys, Lys, K(W) or K(CO(CH2)2SH). It is more preferable that the C-terminal extension has no more than two of any of these residues. If there are two Cys residues in the C-terminal extension, it is preferred that the Cys residues are at the C-terminus. It is even more preferable that the C-terminal extension has no more than one of any of these residues. If there is only one Cys residue in the C-terminal extension, it is preferred that the Cys residue is at the C-terminus. Preferably, the C-terminal extension of the VPAC2 receptor peptide agonist according to the above alternative embodiment comprises an amino acid sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaalo-Xaa11-Xaa12- Xaa13 Formula 2 (SEQ ID NO: 2) wherein:
Xaa] is: GIy, Cys, Lys, or absent;
Xaa2 is: GIy, Arg, Cys, Lys, or absent;
Xaa3 is: Pro, Thr, Ser, Ala, Cys, Lys, or absent; Xaa4 is: Ser, Pro, His, Cys, Lys, or absent;
Xaa5 is: Ser, Arg, Thr, Trp, Lys, Cys, or absent;
Xaa6 is: GIy, Ser, Cys, Lys, or absent;
Xaa7 is: Ala, Asp, Arg, GIu, Lys, GIy, Cys, or absent;
Xaa8 is: Pro, Ser, Ala, Cys, Lys, or absent; Xaag is: Pro, Ser, Ala, Cys, Lys, or absent;
Xaaio is: Pro, Ser, Ala, Arg, Lys, His, Cys, or absent;
Xaaπ is: Ser, Cys, His, Pro, Lys, Arg, or absent;
Xaa12 is: His, Ser, Arg, Lys, Cys, or absent; and
Xaa13 is: His, Ser, Arg, Lys, Cys, or absent; provided that if Xaa1 ; Xaa2, Xaa3, Xaa4, Xaa5, Xaaβ, Xaa7, Xaag, Xaag, Xaa10,
Xaaπ, or Xaa12 is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
Preferably, at least one of Xaai to Xaa13 of the C-terminal extension of Formula 1 or 2 is present. More preferably, at least two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or all of Xaa] to Xaa13 of the C-terminal extension are present. More preferably, the C-terminal extension of the VPAC2 receptor peptide agonist according to the above alternative embodiment comprises an amino acid sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaag-Xaa9-Xaa1o-Xaa11-Xaa12 Formula 3 (SEQ ID NO: 3) wherein:
Xaa! is: GIy, Cys, or absent; Xaa2 is: GIy, Arg, or absent; Xaa3 is: Pro, Thr, or absent; Xaa4 is: Ser, or absent; Xaa5 is: Ser, or absent; Xaa6 is: GIy, or absent; Xaa7 is: Ala, or absent; Xaag is: Pro, or absent; Xaa9 is: Pro, or absent; Xaa10 is: Pro, or absent; Xaaπ is: Ser, Cys, or absent; and Xaa12 is: Cys, or absent; provided that if Xaal5 Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8, Xaa9, Xaaio, or Xaaπ is absent, the next amino acid present downstream is the next amino acid in the C- terminal extension and wherein the C-terminal amino acid may be amidated.
Preferably, at least one of Xaai to Xaa12 of the C-terminal extension of Formula 3 is present. More preferably, at least two, three, four, five, six, seven, eight, nine, ten, eleven, or all of Xaai to Xaa12 of the C-terminal extension are present. An alternative C-terminal extension may comprise an amino acid sequence of the formula:
Xaai -Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaai o
Formula 13 (SEQ ID NO: 13) wherein: Xaai is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa2 is: Arg, Ser, hR, Orn, His, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa3 is: Thr, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; Xaa4 is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa5 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa6 is: Pro, Ser, Ala, Arg, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa7 is: Pro, Ser, Ala, Cys, Lys, K(W), K(CO(CH2)2SH), or absent;
Xaa8 is: Lys, K(W), Pro, Cys, K(CO(CH2)2SH), or absent;
Xaa9 is: K(E-C16), Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent; and
Xaa10 is: Ser, Cys, Lys, K(W), K(CO(CH2)2SH), or absent.
It is preferred that if Xaa1; Xaa2, Xaa3, Xaa4, Xaa5, Xaa6, Xaa7, Xaa8 or Xaa9 of Formula 13 is absent, the next amino acid downstream is the next amino acid in the C- terminal extension. The C-terminal amino acid may be amidated.
Preferably, at least one of Xaa] to Xaa10 of the C-terminal extension of Formula 13 is present. More preferably, at least two, three, four, five, six, seven, eight, nine or all of Xaai to Xaaio of the C-terminal extension are present.
More preferably, the alternative C-terminal extension of Formula 13 is selected from:
Figure imgf000036_0001
Alternative VPAC2 receptor peptide agonists include:
Figure imgf000036_0002
Figure imgf000037_0001
The VPAC2 receptor peptide agonists of the present invention have the advantage that they have enhanced selectivity, potency and/or stability over known VPAC2 receptor peptide agonists. In particular, the addition of the C-terminal sequence of Exendin-4 as the c-capping sequence surprisingly increased the VPAC2 receptor selectivity as well as increasing proteolytic stability.
The term "VPAC2" is used to refer to and in conjunction with the particular receptor (Lutz, et al., FEBS Lett., 458: 197-203 (1999); Adamou, et al., Biochem. Biophys. Res. Commun., 209: 385-392 (1995)) that the agonists of the present invention activate. This term also is used to refer to and in conjunction with the agonists of the present invention.
A "selective VPAC2 receptor peptide agonist" or a "VPAC2 receptor peptide agonist" of the present invention is a peptide that selectively activates the VPAC2 receptor to induce insulin secretion. The sequence for a selective VPAC2 receptor peptide agonist of the present invention has twenty-eight to forty naturally occurring and/or non-naturally occurring amino acids and may or may not additionally comprise a C-terminal extension.
The "C-terminal extension" of the present invention comprises a sequence having from one to thirteen naturally occurring or non-naturally occurring amino acids linked to the C-terminus of the sequence at the N-terminus of the C-terminal extension via a peptide bond.
As used herein, the term "linked to" with reference to the term C-terminal extension, includes the addition or attachment of amino acids or chemical groups directly to the C-terminus of the peptide sequence. Optionally, the selective VPAC2 receptor peptide agonist may also have an N- terminal modification. The term "N-terminal modification" as used herein includes the addition or attachment of amino acids or chemical groups directly to the N-terminus of a peptide and the formation of chemical groups, which incorporate the nitrogen at the N- terminus of a peptide.
The N-terminal modification may comprise the addition of one or more naturally occurring or non-naturally occurring amino acids to the VPAC2 receptor peptide agonist sequence, preferably there are not more than ten amino acids, with one amino acid being more preferred. Naturally occurring amino acids which may be added to the N-terminus include methionine and isoleucine. A modified amino acid added to the N-terminus may be D-histidine. Alternatively, the following amino acids may be added to the N-terminus: SEQ ID NO: 91 Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys-Arg, wherein the Arg is linked to the N-temiinus of the peptide agonist. Preferably, any amino acids added to the N-terminus are linked to the N-terminus by a peptide bond. The term "linked to" as used herein, with reference to the term N-terminal modification, includes the addition or attachment of amino acids or chemical groups directly to the N-terminus of the VPAC2 receptor agonist. The addition of the above N- terminal modifications may be achieved under normal coupling conditions for peptide bond formation. The N-terminus of the peptide agonist may also be modified by the addition of an alkyl group (R), preferably a C1-C16 alkyl group, to form (R)NH-.
Alternatively, the N-terminus of the peptide agonist may be modified by the addition of a group of the formula -C(O)R1 to form an amide of the formula R1C(O)NH-. The addition of a group of the formula -C(O)R1 may be achieved by reaction with an organic acid of the formula R1COOH. Modification of the N-terminus of an amino acid sequence using acylation is demonstrated in the art (e.g. Gozes et at, J. Pharmacol Exp Ther, 273:161-167 (1995)). Addition of a group of the formula -C(O)R1 may result in the formation of a urea group (see WO 01/23240, WO 04/06839) or a carbamate group at the N-terminus. Also, the N-terminus may be modified by the addition of pyroglutamic acid, or 6-aminohexanoic acid.
The N-terminus of the peptide agonist may be modified by the addition of a group of the formula -SO2R5, to form a sulfonamide group at the N-terminus. The N-terminus of the peptide agonist may also be modified by reacting with succinic anhydride to form a succinimide group at the N-terminus. The succinimide group incorporates the nitrogen at the N-terminus of the peptide.
The N-terminus may alternatively be modified by the addition of methionine sulfoxide, biotinyl-6-aminohexanoic acid, or -C(=NH)-NH2. The addition of -C(=NH)- NH2 is a guanidation modification, where the terminal NH2 of the N-terminal amino acid becomes -NH-C(=NH)-NH2.
Most of the sequences of the present invention, including the N-terminal modifications and the C-terminal extensions, contain the standard single letter or three letter codes for the twenty naturally occurring amino acids. The other codes used are defined as follows:
C6 = hexanoyl d = the D isoform (non-naturally occurring) of the respective amino acid, e.g., dA = D-alanine, dS = D-serine, dK = D-lysine hR = homoarginine
Aib = amino isobutyric acid OMe = methoxy NIe = Nor-leucine
NMe = N-methyl attached to the alpha amino group of an amino acid, e.g., NMeA = N-methyl alanine, NMeV = N-methyl valine
Orn = ornithine
K(CO(CH2)2SH) = ε-(3'-mercaptoρroρionyl)-rysine K(W) = ε-(L-tryptophyl)-lysine Abu = α-amino-n-butyric acid or 2-aminobutanoic acid Cit = citrulline
K(Ac) = ε-acetyl lysine Pyr = pyroglutamic acid Aha = 6-aminohexanoic acid
VIP naturally occurs as a single sequence having 28 amino acids. However, PACAP exists as either a 38 amino acid peptide (PACAP-38) or as a 27 amino acid peptide (PACAP-27) with an ami dated carboxyl (Miyata, et al., Biochem Biophys Res Commun, 170:643-648 (1990)). The sequences for VIP, PACAP-27, and PACAP-38 are as follows:
Figure imgf000040_0001
The term "naturally occurring amino acid" as used herein means the twenty amino acids coded for by the human genetic code (i.e. the twenty standard amino acids). These twenty amino acids are: Alanine, Arginine, Asparagine, Aspartic Acid, Cysteine, Glutamine, Glutamic Acid, Glycine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Proline, Serine, Threonine, Tryptophan, Tyrosine and Valine. Examples of "non-naturally occurring amino acids" include both synthetic amino acids and those modified by the body. These include D-amino acids, arginine-like amino acids (e.g., homoarginine), other amino acids having an extra methylene in the side chain ("homo" amino acids), and modified amino acids (e.g norleucine, lysine (isopropyl) - wherein the side chain amine of lysine is modified by an isopropyl group). Also included are amino acids such as ornithine, amino isobutyric acid and 2-aminobutanoic acid. "Selective" as used herein refers to a VPAC2 receptor peptide agonist with increased selectivity for the VPAC2 receptor compared to other known receptors. The degree of selectivity is determined by a ratio of VPAC2 receptor binding affinity to VPACl receptor binding affinity and by a ratio of VPAC2 receptor binding affinity to PACl receptor binding affinity. Binding affinity is determined as described below in Example 4.
"Insulinotropic activity" refers to the ability to stimulate insulin secretion in response to elevated glucose levels, thereby causing glucose uptake by cells and decreased plasma glucose levels. Insulinotropic activity can be assessed by methods known in the art, including using experiments that measure VPAC2 receptor binding activity or receptor activation (e.g. insulin secretion by insulinoma cell lines or islets, intravenous glucose tolerance test (IVGTT), intraperitoneal glucose tolerance test (IPGTT), and oral glucose tolerance test (OGTT)). Insulinotropic activity is routinely measured in humans by measuring insulin levels or C-peptide levels. Selective VPAC2 receptor peptide agonists of the present invention have insulinotropic activity.
"In vitro potency" as used herein is the measure of the ability of a peptide to activate the VPAC2 receptor in a cell-based assay. In vitro potency is expressed as the "EC5o" which is the effective concentration of compound that results in a 50% of maximum increase in activity in a single dose-response experiment. For the purposes of the present invention, in vitro potency is determined using two different assays: DiscoveRx and Alpha Screen. See Examples 3 and 5 for further details of these assays. Whilst these assays are performed in different ways, the results demonstrate a general correlation between the two assays.
"Percent (%) sequence identity" as used herein is used to denote sequences which when aligned have similar (identical or conservatively replaced) amino acids in like positions or regions, where identical or conservatively replaced amino acids are those which do not alter the activity or function of the protein as compared to the starting protein. For example, two amino acid sequences with at least 85% identity to each other have at least 85% similar (identical or conservatively replaced residues) in a like position when aligned optimally allowing for up to 3 gaps, with the proviso that in respect of the gaps a total of not more than 15 amino acid residues is affected. The reference peptide used for the percentage sequence identity calculations herein is:
P487 C6-
SEQ ID HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQSIOrnOmGGPSSGA
NO:55 PPPS-NH2
Percent sequence identity may be calculated by determining the number of residues that differ between a peptide encompassed by the present invention and a reference peptide such as P487 (SEQ ID NO: 55), taking that number and dividing it by the number of amino acids in the reference peptide (e.g. 39 amino acids for P487), multiplying the result by 100, and subtracting that resulting number from 100. For example, a sequence having 39 amino acids with four amino acids that are different from P487 would have a percent (%) sequence identity of 90% (e.g. 100 - ((4 / 39) x 100)). For a sequence that is longer than 39 amino acids, the number of residues that differ from the P487 sequence will include the additional amino acids over 39 for purposes of the aforementioned calculation. For example, a sequence having 40 amino acids, with four amino acids different from the 39 amino acids in the P487 sequence and with one additional amino acid at the carboxy terminus which is not present in the P487 sequence, would have a total of five amino acids that differ from P487. Thus, this sequence would have a percent (%) sequence identity of 87% (e.g. 100 - ((5 / 39) x 100)). The degree of sequence identity may be determined using methods well known in the art (see, for example, Wilbur, WJ. and Lipman, DJ., Proc. Natl. Acad. ScL USA 80:726-730 (1983) and Myers E. and Miller W., Comput. Appl. Biosci. 4:11-17 (1988)). One program which may be used in determining the degree of similarity is the MegAlign Lipman-Pearson one pair method (using default parameters) which can be obtained from DNAstar Inc, 1128, Selfpark Street, Madison, Wisconsin, 53715, USA as part of the Lasergene system. Another program, which may be used, is Clustal W. This is a multiple sequence alignment package developed by Thompson et al {Nucleic Acids Research, 22(22):4673- 4680(1994)) for DNA or protein sequences. This tool is useful for performing cross- species comparisons of related sequences and viewing sequence conservation. Clustal W is a general purpose multiple sequence alignment program for DNA or proteins. It produces biologically meaningful multiple sequence alignments of divergent sequences. It calculates the best match for the selected sequences, and lines them up so that the identities, similarities and differences can be seen. Evolutionary relationships can be seen via viewing Cladograms or Phylograms.
The sequence for a selective VPAC2 receptor peptide agonist of the present invention is selective for the VPAC2 receptor and preferably has a sequence identity in the range of 60% to 70%, 60% to 65%, 65% to 70%, 70% to 80%, 70% to 75%, 75% to 80%, 80% to 90%, 80% to 85%, 85% to 90%, 90% to 97%, 90% to 95%, or 95% to 97%, with P487 (SEQ ID NO: 55). Preferably, the sequence has a sequence identity of greater than 82% with P487 (SEQ ID NO: 55). More preferably, the sequence has greater than 90% sequence identity with P487 (SEQ ID NO: 55). Even more preferably, the sequence has greater than 92% sequence identity with P487 (SEQ ID NO: 55). Yet more preferably, the sequence has greater than 95% sequence identity or 97% sequence identity with P487 (SEQ ID NO: 55). The term "C1-C16 alkyl" as used herein means a monovalent saturated straight, branched or cyclic chain hydrocarbon radical having from 1 to 16 carbon atoms or when cyclic, having from 3 to 16 carbon atoms. Thus the term "Ci-C16 alkyl" includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n- heptyl, n-octyl, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. The C1-C16 alkyl group may be optionally substituted with one or more substituents including, for example, aryl, C1-C6 alkoxy, -OH, halogen, -CF3 and -SH.
The term "C1- C6 alkyl" as used herein means a monovalent saturated straight, branched or cyclic chain hydrocarbon radical having from 1 to 6 carbon atoms or when cyclic, having from 3 to 6 carbon atoms. Thus the term "Ci-C6 alkyl" includes, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl. The Ci-C6 alkyl group may be optionally substituted with one or more substituents.
The term "C2-C6 alkenyl" as used herein means a monovalent straight, branched or cyclic chain hydrocarbon radical having at least one double bond and having from 2 to 6 carbon atoms or when cyclic, having from 3 to 6 carbon atoms. Thus the term "C2-C6 alkenyl" includes vinyl, prop-2-enyl, but-3-enyl, pent-4-enyl and isopropenyl. The C2-C6 alkenyl group may be optionally substituted with one or more substituents.
The term "C2-C6 alkynyl" as used herein means a monovalent straight or branched chain hydrocarbon radical having at least one triple bond and having from 2 to 6 carbon atoms. Thus the term "C2-C6 alkynyl" includes prop-2-ynyl, but-3-ynyl and pent-4-ynyl. The C2-C6 alkynyl may be optionally substituted with one or more substituents.
The term "C1-C6 alkoxy" as used herein means a monovalent unsubstituted saturated straight-chain or branched-chain hydrocarbon radical having from 1 to 6 carbon atoms linked to the point of substitution by a divalent O radical. Thus the term "C1-C6 alkoxy" includes, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy and tert-butoxy. The C1-C6 alkoxy group may be optionally substituted with one or more substituents.
The term "halo" or "halogen" means fluorine, chlorine, bromine or iodine. The term "aryl" when used alone or as part of a group is a 5 to 10 membered aromatic or heteroaromatic group including a phenyl group, a 5 or 6- membered monocyclic heteroaromatic group, each member of which may be optionally substituted with 1, 2, 3, 4 or 5 substituents (depending upon the number of available substitution positions), a naphthyl group or an 8-, 9- or 10- membered bicyclic heteroaromatic group, each member of which may be optionally substituted with 1, 2, 3, 4, 5 or 6 substituents (depending on the number of available substitution positions). Within this definition of aryl, suitable substitutions include Ci-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, -NH2, -OH, halogen, -SH and CF3.
The term "aryl C1-C4 alkyl" as used herein means a C1-C4 alkyl group substituted with an aryl. Thus the term "aryl C1-C4 alkyl" includes benzyl, 1-phenylethyl (α- methylbenzyl), 2-phenylethyl, 1-naphthalenemethyl or 2-naphthalenemethyl. The term "naphthyl" includes 1-naphthyl, and 2-naphthyl. 1-naphthyl is preferred.
The term "benzyl" as used herein means a monovalent unsubstituted phenyl radical linked to the point of substitution by a -CH2- group.
The term "5- or 6-membered monocyclic heteroaromatic group" as used herein means a monocyclic aromatic group with a total of 5 or 6 atoms in the ring wherein from 1 to 4 of those atoms are each independently selected from N, O and S. Preferred groups have 1 or 2 atoms in the ring which are each independently selected from N, O and S. Examples of 5-membered monocyclic heteroaromatic groups include pyrrolyl (also called azolyl), furanyl, thienyl, pyrazolyl (also called lH-pyrazolyl and 1,2-diazolyl), imidazolyl, oxazolyl (also called 1,3-oxazolyl), isoxazolyl (also called 1,2-oxazolyl), thiazolyl (also called 1,3-thiazolyl), isothiazolyl (also called 1,2-thiazolyl), triazolyl, oxadiazolyl, thiadiazolyl, tetrazolyl, oxatriazolyl and thiatriazolyl. Examples of 6- membered monocyclic heteroaromatic groups include pyridinyl, pyrimidyl, pyrazinyl, pyridazinyl and triazinyl. The term "8-, 9- or 10-membered bicyclic heteroaromatic group" as used herein means a fused bicyclic aromatic group with a total of 8, 9 or 10 atoms in the ring system wherein from 1 to 4 of those atoms are each independently selected from N, O and S. Preferred groups have from 1 to 3 atoms in the ring system which are each independently selected from N, O and S. Suitable 8-membered bicyclic heteroaromatic groups include imidazo[2, 1-b] [1 ,3]thiazolyl, thieno[3 ,2-b]thienyl, thieno[2,3-d] [ 1 ,3]thiazolyl and thieno[2,3-d]imidazolyl. Suitable 9-membered bicyclic heteroaromatic groups include indolyl, isoindolyl, benzofuranyl (also called benzo[b]furanyl), isobenzofuranyl (also called benzo[c]furanyl), benzothienyl (also called benzo[b]thienyl), isobenzothienyl (also called benzo[c]thienyl), indazolyl, benzimidazolyl, 1,3-benzoxazolyl, 1,2-benzisoxazolyl, 2,1-benzisoxazolyl, 1,3-benzothiazolyl, 1,2-benzoisothiazolyl, 2,1-benzoisothiazolyl, benzotriazolyl, 1,2,3-benzoxadiazolyl, 2,1,3-benzoxadiazolyl, 1,2,3-benzothiadiazolyl, 2,1,3-benzothiadiazolyl, thienopyridinyl, purinyl and imidazo[l,2-a]pyridine. Suitable 10- membered bicyclic heteroaromatic groups include quinolinyl, isoquinolinyl, cinnolinyl, quinazolinyl, quinoxalinyl, 1,5-naphthyridyl, 1,6-naphthyridyl, 1,7-naphthyridyl and 1,8- naphthyridyl.
According to a preferred embodiment of the present invention, there is provided a VPAC2 receptor peptide agonist comprising a peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199, and a C-terminal extension selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH2 (SEQ ID NO: 10), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH2 (SEQ ID NO: 12). In this embodiment, it is especially preferred that the C-terminal extension is selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH2 (SEQ ID NO: 8), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH2 (SEQ ID NO: 12). According to a more preferred embodiment of the present invention, there is provided a VPAC2 receptor peptide agonist comprising a peptide sequence selected from SEQ ID NO: 17 to 45, 92 to 110 and 145 to 199 and a C-terminal extension selected from: GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH2 (SEQ ID N0:8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH2 (SEQ ID NO: 10),
GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH2 (SEQ ID NO: 12) and wherein the VPAC2 receptor peptide agonist further comprises a N-terminal modification, which modification is the addition of acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3-phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3-mercaptopropionyl, biotinyl-6-aminohexanoic acid (6-aminocaproic acid), and -C(=NH)-NH2. In this embodiment, it is more preferred that the N-terminal modification is the addition of acetyl or hexanoyl. According to a preferred embodiment of the present invention, there is provided a VPAC2 receptor peptide agonist comprising an amino acid sequence of Formula 4 (SEQ ID NO: 4) and a C-terminal extension selected from GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9),
GRPSSGAPPPS-NH2 (SEQ ID NO: 10), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH2 (SEQ ID NO: 12), and wherein the VPAC2 receptor peptide agonist further comprises a N-terminal modification, which modification is the addition of acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3- phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3- mercaptopropionyl, biotinyl-6-aminohexanoic acid (6-aminocaproic acid), and - C(=NH)-NH2. In this embodiment, it is more preferred that the N-terminal modification is the addition of acetyl or hexanoyl.
According to a more preferred embodiment of the present invention, there is provided a VPAC2 receptor peptide agonist comprising an amino acid sequence of
Formula 4 (SEQ ID NO: 4), wherein Xaai5 is Aib, Xaa20 is Aib and Xaaπ, Xaa2i, Xaa27 and Xaa2g are all Orn, and a C-terminal extension selected from GGPSSGAPPPS (SEQ ID NO: 5), GGPSSGAPPPS-NH2 (SEQ ID NO: 6), GGPSSGAPPPC (SEQ ID NO: 7), GGPSSGAPPPC-NH2 (SEQ ID NO: 8), GRPSSGAPPPS (SEQ ID NO: 9), GRPSSGAPPPS-NH2 (SEQ ID NO: 10), GGPSSGAPPPCC (SEQ ID NO: 11) and GGPSSGAPPPCC-NH2 (SEQ ID NO: 12), and wherein the VPAC2 receptor peptide agonist further comprises a N-terminal modification, which modification is the addition of acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3- phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3- mercaptopropionyl, biotinyl-6-aminohexanoic acid (6-aminocaproic acid), and -
C(=NH)-NH2. In this embodiment, it is more preferred that Xaa15 is Aib, Xaa20 is Aib, Xaaj2, Xaa21, Xaa27 and Xaa2g are all Orn, Xaag is GIu, Xaa9 is GIn and Xaaio is Tyr(OMe). It is especially preferred that Xaa15 is Aib, Xaa2o is Aib, Xaa12, Xaa21, Xaa27 and Xaa28 are all Orn, Xaa8 is GIu, Xaa9 is GIn, Xaa10 is Tyr(OMe), and Xaa23 and/or Xaa25 is Aib.
The present invention encompasses the discovery that specific amino acids added to the C-terminus of a peptide sequence for a VPAC2 receptor peptide agonist may protect the peptide as well as may enhance activity, selectivity, and/or potency. For example, these C-terminal extensions may stabilize the helical structure of the peptide and stabilize sites located near to the C-terminus, which are prone to enzymatic cleavage. Furthermore, many of the C-terminally extended peptides disclosed herein may be more selective for the VPAC2 receptor and may be more potent than VIP, PACAP, and other known VPAC2 receptor peptide agonists. An example of a preferred C-terminal extension is the extension peptide of exendin-4 as the C-capping sequence. Exendin-4 is found in the salivary excretions from the GiIa Monster, Heloderma Suspectum, (Eng et al, J.BioLChem., 267(11):7402-7405 (1992)). Other examples of C-terminal extensions are the C-terminal sequences of helodermin and helospectin. Helodermin and helospectin are also found in the salivary excretions of the GiIa Monster.
It has furthermore been discovered that modification of the N-terminus of the VPAC2 receptor peptide agonist may enhance potency and/or provide stability against DPP-IV cleavage. VIP and some known VPAC2 receptor peptide agonists are susceptible to cleavage by various enzymes and, thus, have a short in vivo half-life. Various enzymatic cleavage sites in the VPAC2 receptor peptide agonists are discussed below. The cleavage sites are discussed relative to the amino acid positions in VIP (SEQ ID NO: 14), and are applicable to the sequences noted herein. Cleavage of the peptide agonist by the enzyme dipeptidyl-peptidase-IV (DPP-IV) occurs between position 2 (serine in VIP) and position 3 (aspartic acid in VIP). The compounds of the present invention may be rendered more stable to DPP-IV cleavage in this region by the addition of a N-terminal modification. Examples of N-terminal modifications that may improve stability against DPP-IV cleavage include the addition of acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3- phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3- mercaptopropionyl, biotinyl-6-aminohexanoic acid, or -C(=NH2)-NH2. Preferably, the N-terminal modification is the addition of acetyl or hexanoyl.
There are chymotrypsin cleavage sites in wild-type VIP between the amino acids 10 and 11 (tyrosine and threonine) and those at 22 and 23 (tyrosine and leucine). Making substitutions at position 10 and/or 11 and position 22 and/or 23 may increase the stability of the peptide at these sites. For example, substitution of tyrosine at position 10 and/or position 22 with Tyr(OMe) may increase stability.
There is a trypsin cleavage site between the amino acids at positions 12 and 13 of wild-type VIP. Certain amino acids render the peptide less susceptible to cleavage at this site, for example, ornithine and homoarginine at position 12 and amino isobutyric acid at position 13.
In wild-type VIP, and in numerous VPAC2 receptor peptide agonists known in the art, there are cleavage sites between the basic amino acids at positions 14 and 15 and between those at positions 20 and 21. The selective VPAC2 receptor peptide agonists of the present invention may have improved proteolytic stability in-vivo due to substitutions at these sites. The preferred substitutions at these sites are those which render the peptide less susceptible to cleavage by trypsin-like enzymes, including trypsin. For example, leucine at position 14, amino isobutyric acid at position 15, amino isobutyric acid and glutamine at position 20, and ornithine at position 21 are all preferred substitutions which may lead to improved stability.
There is also a cleavage site between the amino acids at positions 25 and 26 of wild type VIP. The region of the VPAC2 receptor peptide agonist encompassing the amino acids at positions 27, 28, and 29 is also susceptible to enzyme cleavage. The addition of a C-terminal extension may render the peptide agonist more stable against neuroendopeptidase (NEP). This region may also be attacked by trypsin-like enzymes. If that occurs, the peptide agonist may lose its C-terminal extension with the additional carboxypeptidase activity leading to an inactive form of the peptide. Preferred substitutions which may increase resistance to cleavage in this region include ornithine at position 27, ornithine, amino isobutyric acid, or glutamine at position 28 and ornithine, or lysine at position 29.
In addition to selective VPAC2 receptor peptide agonists with resistance to cleavage by various peptidases, the selective VPAC2 peptide receptor agonists of the present invention may also encompass peptides with enhanced selectivity for the VPAC2 receptor, increased potency, and/or increased stability compared with some peptides known in the art. The potency and selectivity of various VPAC2 receptor peptide agonists of the present invention is reported in Examples 3, 4 and 5. Table 1 in Example 3 provides a list of selective VPAC2 receptor peptide agonists and their corresponding in vitro potency results. Preferably, the selective VPAC2 receptor peptide agonists of the present invention have an EC50 value less than 10 nM. More preferably, the selective VPAC2 receptor peptide agonists of the present invention have an EC50 value less than 2 nM. Evan more preferably, the EC50 value is less than 1 nM. Still more preferably, the EC50 value is less than 0.5 nM.
Table 2 in Example 4 provides a list of VPAC2 receptor peptide agonists and their corresponding binding affinity results for human VPAC2, VPACl, and PACl. See Example 4 for further details of these assays. The degree of selectivity is determined by a ratio of VPAC2 receptor binding affinity to VPACl receptor binding affinity and by a ratio of VPAC2 receptor binding affinity to PACl receptor binding affinity. Preferably, the agonists of the present invention have a selectivity ratio where the affinity for the VPAC2 receptor is at least 50 times greater than for the VPACl and/or for PACl receptors. More preferably, this affinity is at least 100 times greater for VPAC2 than for VPACl and/or for PACl. Even more preferably, the affinity is at least 200 times greater for VPAC2 than for VPACl and/or for PACl. Still more preferably, the affinity is at least 500 times greater for VPAC2 than for VPACl and/or for PACl. Yet more preferably, the ratio is at least 1000 times greater for VPAC2 than for VPACl and/or for PACl. As used herein, "selective VPAC2 receptor peptide agonists" also include pharmaceutically acceptable salts of the agonists described herein. A selective VPAC2 receptor peptide agonist of this invention can possess a sufficiently acidic, a sufficiently basic, or both functional groups, and accordingly react with any of a number of inorganic bases, and inorganic and organic acids, to form a salt. Acids commonly employed to form acid addition salts are inorganic acids such as hydrochloric acid, hydrobromic acid, hydroiodic acid, sulfuric acid, phosphoric acid, and the like, and organic acids such as p- toluenesulfonic acid, methanesulfonic acid, oxalic acid, p-bromophenyl-sulfonic acid, carbonic acid, succinic acid, citric acid, benzoic acid, acetic acid, trifluoroacetic acid, and the like. Examples of such salts include the sulfate, pyrosulfate, bisulfate, sulfite, bisulfite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate, chloride, bromide, iodide, acetate, propionate, decanoate, caprylate, acrylate, formate, isobutyrate, caproate, heptanoate, propiolate, oxalate, malonate, succinate, suberate, sebacate, fumarate, maleate, butyne-l,4-dioate, hexyne-l,6-dioate, benzoate, chlorobenzoate, methylbenzoate, dinitrobenzoate, hydroxybenzoate, methoxybenzoate, phthalate, sulfonate, xylenesulfonate, phenylacetate, phenylpropionate, phenylbutyrate, citrate, lactate, gamma-hydroxybutyrate, glycolate, tartrate, methanesulfonate, propanesulfonate, naphthalene-1-sulfonate, naphthalene-2-sulfonate, mandelate, and the like.
Base addition salts include those derived from inorganic bases, such as ammonium or alkali or alkaline earth metal hydroxides, carbonates, bicarbonates, and the like. Such bases useful in preparing the salts of this invention thus include sodium hydroxide, potassium hydroxide, ammonium hydroxide, potassium carbonate, and the like.
The selective VPAC2 receptor peptide agonists of the present invention are preferably formulated as pharmaceutical compositions. Standard pharmaceutical formulation techniques may be employed such as those described in Remington' s Pharmaceutical Sciences, Mack Publishing Company, Easton, PA. The selective VPAC2 receptor peptide agonists of the present invention may be formulated for administration through the buccal, topical, oral, transdermal, nasal, or pulmonary route, or for parenteral administration.
Parenteral administration can include, for example, systemic administration, such as by intramuscular, intravenous, subcutaneous, intradermal, or intraperitoneal injection. The selective VPAC2 receptor peptide agonists can be administered to the subject in conjunction with an acceptable pharmaceutical carrier, diluent, or excipient as part of a pharmaceutical composition for treating NLDDM, or the disorders discussed below. The pharmaceutical composition can be a solution or, if administered parenterally, a suspension of the VPAC2 receptor peptide agonist or a suspension of the VPAC2 receptor peptide agonist complexed with a divalent metal cation such as zinc. Suitable pharmaceutical carriers may contain inert ingredients which do not interact with the peptide or peptide derivative. Suitable pharmaceutical carriers for parenteral administration include, for example, sterile water, physiological saline, bacteriostatic saline (saline containing about 0.9% mg/ml benzyl alcohol), phosphate-buffered saline, Hank's solution, Ringer's-lactate and the like. Some examples of suitable excipients include lactose, dextrose, sucrose, trehalose, sorbitol, and mannitol. The VPAC2 receptor peptide agonists of the invention may be formulated for administration such that blood plasma levels are maintained in the efficacious range for extended time periods. The main barrier to effective oral peptide drug delivery is poor bioavailability due to degradation of peptides by acids and enzymes, poor absorption through epithelial membranes, and transition of peptides to an insoluble form after exposure to the acidic pH environment in the digestive tract. Oral delivery systems for peptides such as those encompassed by the present invention are known in the art. For example, VPAC2 receptor peptide agonists can be encapsulated into microspheres composed of a commercially available, biocompatible, biodegradable polymer, poly(lactide-co-glycolide)-COOH and olive oil as a filler (see Joseph, et al. Diabetologia 43:1319-1328 (2000)). Other types of microsphere technology are also available commercially such as Medisorb® and Prolease® biodegradable polymers from Alkermes. Medisorb® polymers can be produced with any of the lactide isomers. Lactiderglycolide ratios can be varied between 0:100 and 100:0 allowing for a broad range of polymer properties. This allows for the design of delivery systems and implantable devices with resorption times ranging from weeks to months. Emisphere has published numerous articles discussing oral delivery technology for peptides and proteins. For example, see WO 95/28838 by Leone-bay et al. which discloses specific carriers comprised of modified amino acids to facilitate absorption. The selective VPAC2 receptor peptide agonists described herein can be used to treat subjects with a wide variety of diseases and conditions. Agonists encompassed by the present invention exert their biological effects by acting at a receptor referred to as the VPAC2 receptor. Subjects with diseases and/or conditions that respond favourably to VPAC2 receptor stimulation or to the administration of VPAC2 receptor peptide agonists can therefore be treated with the VPAC2 agonists of the present invention. These subjects are said to "be in need of treatment with VPAC2 agonists" or "in need of VPAC2 receptor stimulation".
The selective VPAC2 receptor peptide agonists of the present invention may be employed to treat diabetes, including both type 1 and type 2 diabetes (non-insulin dependent diabetes mellitus or NIDDM). The agonists may also be used to treat subjects requiring prophylactic treatment with a VPAC2 receptor agonist, e.g., subjects at risk for developing NIDDM. Such treatment may delay the onset of diabetes and diabetic complications. Additional subjects which may be treated with the agonists of the present invention include those with impaired glucose tolerance (IGT) (Expert Committee on Classification of Diabetes Mellitus, Diabetes Care 22 (Supp. 1):S5, 1999) or impaired fasting glucose (IFG) (Charles, et al., Diabetes 40:796, 1991), subjects whose body weight is about 25% above normal body weight for the subject's height and body build, subjects having one or more parents with NIDDM, subjects who have had gestational diabetes, and subjects with metabolic disorders such as those resulting from decreased endogenous insulin secretion. The selective VPAC2 receptor peptide agonists may be used to prevent subjects with impaired glucose tolerance from proceeding to develop NIDDM, prevent pancreatic β-cell deterioration, induce β-cell proliferation, improve β- cell function, activate dormant β-cells, differentiate cells into β-cells, stimulate β-cell replication, and inhibit β-cell apoptosis. Other diseases and conditions that may be treated or prevented using the VPAC2 receptor peptide agonists of the invention include: Maturity-Onset Diabetes of the Young (MODY) (Herman, et al., Diabetes 43:40, 1994); Latent Autoimmune Diabetes Adult (LADA) (Zimmet, et al., Diabetes Med. 11:299, 1994); gestational diabetes (Metzger, Diabetes, 40:197, 1991); metabolic syndrome X, dyslipidemia, hyperglycemia, hyperinsulinemia, hypertriglyceridemia, and insulin resistance.
The selective VPAC2 receptor peptide agonists of the invention may also be used to treat secondary causes of diabetes (Expert Committee on Classification of Diabetes Mellitus, Diabetes Care 22 (Supp. 1):S5, 1999). Such secondary causes include glucocorticoid excess, growth hormone excess, pheochromocytoma, and drug-induced diabetes. Drugs that may induce diabetes include, but are not limited to, pyriminil, nicotinic acid, glucocorticoids, phenytoin, thyroid hormone, β-adrenergic agents, α- interferon and drugs used to treat HIV infection.
The selective VPAC2 receptor peptide agonists of the present invention may be effective in the suppression of food intake and the treatment of obesity.
The selective VPAC2 receptor peptide agonists of the present invention may also be effective in the prevention or treatment of such disorders as atherosclerotic disease, hyperlipidemia, hypercholesteremia, low HDL levels, hypertension, primary pulmonary hypertension, cardiovascular disease (including atherosclerosis, coronary heart disease, and coronary artery disease), cerebrovascular disease and peripheral vessel disease; and for the treatment of lupus, polycystic ovary syndrome, carcinogenesis, hyperplasia, male and female reproduction problems, sexual disorders, ulcers, sleep disorders, disorders of lipid and carbohydrate metabolism, circadian dysfunction, growth disorders, disorders of energy homeostasis, immune diseases including autoimmune diseases (e.g., systemic lupus erythematosus), as well as acute and chronic inflammatory diseases, rheumatoid arthritis, and septic shock.
The selective VPAC2 receptor peptide agonists of the present invention may also be useful for treating physiological disorders related to, for example, cell differentiation to produce lipid accumulating cells, regulation of insulin sensitivity and blood glucose levels, which are involved in, for example, abnormal pancreatic β-cell function, insulin secreting tumors and/or autoimmune hypoglycemia due to autoantibodies to insulin, autoantibodies to the insulin receptor, or autoantibodies that are stimulatory to pancreatic β -cells, macrophage differentiation which leads to the formation of atherosclerotic plaques, inflammatory response, carcinogenesis, hyperplasia, adipocyte gene expression, adipocyte differentiation, reduction in the pancreatic β -cell mass, insulin secretion, tissue sensitivity to insulin, liposarcoma cell growth, polycystic ovarian disease, chronic anovulation, hyperandrogenism, progesterone production, steroidogenesis, redox potential and oxidative stress in cells, nitric oxide synthase (NOS) production, increased gamma glutamyl transpeptidase, catalase, plasma triglycerides, HDL, and LDL cholesterol levels, and the like.
In addition, the selective VPAC2 receptor peptide agonists of the invention may be used for treatment of asthma (Bolin, et al., Biopolymer 37:57-66 (1995); U.S. Patent No. 5,677,419; showing that polypeptide R3P0 is active in reducing guinea pig tracheal smooth muscle); for hypotension induction (VDP induces hypotension, tachycardia, and facial flushing in asthmatic patients (Morice, et al., Peptides 7:279-280 (1986); Morice, et al., Lancet 2:1225-1227 (1983)); for the treatment of male reproduction problems (Siow, et al. , Arch. Androl. 43(1):67-71 (1999)); as an anti-apoptosis/neuroprotective agent (Brenneman, et al., Ann. N. Y. Acad. Sci. 865:207-12 (1998)); for cardioprotection during ischemic events ( Kalfin, et al., J. Pharmacol. Exp. Ther. 1268(2):952-8 (1994); Das, et al., Ann. N. Y. Acad. ScL 865:297-308 (1998)); for manipulation of the circadian clock and its associated disorders (Hamar, et al., Cell 109:497-508 (2002); Shen, et al., Proc. Natl. Acad. ScL 97:11575-80, (2000)); and as an anti-ulcer agent (Tuncel, et al., Ann. N. Y. Acad. Sci. 865:309-22, (1998)).
An "effective amount" of a selective VPAC2 receptor peptide agonist is the quantity that results in a desired therapeutic and/or prophylactic effect without causing unacceptable side effects when administered to a subject in need of VPAC2 receptor stimulation. A "desired therapeutic effect" includes one or more of the following: 1) an amelioration of the symptom(s) associated with the disease or condition; 2) a delay in the onset of symptoms associated with the disease or condition; 3) increased longevity compared with the absence of the treatment; and 4) greater quality of life compared with the absence of the treatment. For example, an "effective amount" of a VPAC2 agonist for the treatment of NIDDM is the quantity that would result in greater control of blood glucose concentration than in the absence of treatment, thereby resulting in a delay in the onset of diabetic complications such as retinopathy, neuropathy, or kidney disease. An "effective amount" of a selective VPAC2 receptor peptide agonist for the prevention of NEDDM is the quantity that would delay, compared with the absence of treatment, the onset of elevated blood glucose levels that require treatment with anti-hypoglycemic drugs such as sulfonylureas, thiazolidinediones, insulin, and/or bisguanidines.
An "effective amount" of the selective VPAC2 receptor peptide agonist administered to a subject will also depend on the type and severity of the disease and on the characteristics of the subject, such as general health, age, sex, body weight and tolerance to drugs. The dose of selective VPAC2 peptide receptor agonist effective to normalize a patient's blood glucose will depend on a number of factors, among which are included, without limitation, the subject's sex, weight and age, the severity of inability to regulate blood glucose, the route of administration and bioavailability, the pharmacokinetic profile of the peptide, the potency, and the formulation.
A typical dose range for the selective VPAC2 receptor peptide agonists of the present invention will range from about 1 μg per day to about 5000 μg per day. Preferably, the dose ranges from about 1 μg per day to about 2500 μg per day, more preferably from about 1 μg per day to about 1000 μg per day. Even more preferably, the dose ranges from about 5 μg per day to about 100 μg per day. A further preferred dose range is from about 10 μg per day to about 50 μg per day. Most preferably, the dose is about 20 μg per day. A "subject" is a mammal, preferably a human, but can also be an animal, e.g., companion animals (e.g., dogs, cats, and the like), farm animals (e.g., cows, sheep, pigs, horses, and the like) and laboratory animals (e.g., rats, mice, guinea pigs, and the like). The selective VPAC2 receptor peptide agonists of the present invention can be prepared by using standard methods of solid-phase peptide synthesis techniques. Peptide synthesizers are commercially available from, for example, Rainin-PTI Symphony Peptide Synthesizer (Tucson, AZ). Reagents for solid phase synthesis are commercially available, for example, from Glycopep (Chicago, IL). Solid phase peptide synthesizers can be used according to manufacturer's instructions for blocking interfering groups, protecting the amino acid to be reacted, coupling, decoupling, and capping of unreacted amino acids.
Typically, an α-iV-protected amino acid and the N-terminal amino acid on the growing peptide chain on a resin is coupled at room temperature in an inert solvent such as dimethylformamide, N-methylpyrrolidone or methylene chloride in the presence of coupling agents such as dicyclohexylcarbodiimide and 1-hydroxybenzotriazole and a base such as diisopropylethylamine. The α-iV-protecting group is removed from the resulting peptide resin using a reagent such as trifluoroacetic acid or piperidine, and the coupling reaction repeated with the next desired iV-protected amino acid to be added to the peptide chain. Suitable amine protecting groups are well known in the art and are described, for example, in Green and Wuts, "Protecting Groups in Organic Synthesis", John Wiley and Sons, 1991. Examples include t-butyloxycarbonyl (tBoc) and fluorenylmethoxycarbonyl (Fmoc).
The selective VPAC2 receptor peptide agonists may also be synthesized using standard automated solid-phase synthesis protocols using t-butoxycarbonyl- or fluorenylmethoxycarbonyl-alpha-amino acids with appropriate side-chain protection. After completion of synthesis, modification of the N-terminus may be accomplished by reacting the α-amino group with, for example: (i) active esters (using similar protocols as described above for the introduction of an or-iV-protected amino acid); (ii) aldehydes in presence of a reducing agent (reductive amination procedure); and (iii) guanidation reagents. Then, peptides are cleaved from the solid-phase support with simultaneous side- chain deprotection using standard hydrogen fluoride methods or trifluoroacetic acid (TFA). Crude peptides are then further purified using Reversed-Phase Chromatography on VYDAC Cl 8 columns using acetonitrile gradients in 0.1% trifluoroacetic acid (TFA). To remove acetonitrile, peptides are lyophilized from a solution containing 0.1 % TFA, acetonitrile and water. Purity can be verified by analytical reversed phase chromatography. Identity of peptides can be verified by mass spectrometry. Peptides can be solubilized in aqueous buffers at neutral pH.
The peptide agonists of the present invention may also be made by recombinant methods known in the art using both eukaryotic and prokaryotic cellular hosts.
Various preferred features and embodiments of the present invention will now be described with reference to the following non-limiting examples.
Example 1 - Preparation of the Selective VPAC2 Receptor Peptide Agonists by Solid Phase t-Boc Chemistry:
Approximately 0.5-0.6 grams (0.38-0.45 mmole) Boc Ser(Bzl)-PAM resin is placed in a standard 60 mL reaction vessel. Double couplings are run on an Applied Biosystems ABI430A peptide synthesizer.
The following side-chain protected amino acids (2 mmole cartridges of Boc amino acids) are obtained from Midwest Biotech (Fishers, IN) and are used in the synthesis:
Arg-Tosyl (TOS), Asp-δ-cyclohexyl ester (OcHx), Glu-δ-cycohexyl ester (OcHx), His-benzyloxymethyl(BOM), Lys-2-chlorobenzyloxycarbonyl (2C1-Z), Ser-O- benzyl ether (OBzI), Thr-O-benzyl ether (OBzI), Trp-formyl (CHO), and Tyr-2- bromobenzyloxycarbonyl (2Br-Z).
Trifluoroacetic acid (TFA), di-isopropylethylamine (DIEA), 0.5 M hydroxybenzotriazole (HOBt) in DMF and 0.5 M dicyclohexylcarbodiimide (DCC) in dichloromethane are purchased from PE- Applied Biosystems (Foster City, CA). Dimethylformamide (DMF-Burdick and Jackson) and dichloromethane (DCM- Mallinkrodt) are purchased from Mays Chemical Co. (Indianapolis, IN).
Standard double couplings are run using either symmetric anhydride or HOBt esters, both formed using DCC. At the completion of the syntheses, the N-terminal Boc group is removed and the peptidyl resins are treated with 20% piperidine in DMF to deformylate the Trp side chain if Trp is present in the sequence. For N-terminal acylation, four-fold excess of symmetric anhydride of the corresponding acid is added onto the peptide resin. The symmetric anhydride is prepared by diisopropylcarbodiimide (DIC) activation in DCM. The reaction is allowed to proceed for 4 hours and monitored by ninhydrin test. After washing with DCM, the resins are transferred to a TEFLON reaction vessel and are dried in vacuo.
Cleavages are done by attaching the reaction vessels to a HF (hydrofluoric acid) apparatus (Penninsula Laboratories). 1 mL m-cresol per gram/resin is added and 10 mL HF (purchased from AGA, Indianapolis, IN) is condensed into the pre-cooled vessel. 1 mL DMS per gram resin is added when methionine is present. The reactions are stirred one hour in an ice bath. The HF is removed in vacuo. The residues are suspended in ethyl ether. The solids are filtered and are washed with ether. Each peptide is extracted into aqueous acetic acid and either is freeze dried or is loaded directly onto a reverse- phase column.
Purifications are run on a 2.2 x 25cm VYDAC Cl 8 column in buffer A (0.1% TFA in water). A gradient of 20% to 90% B (0.1% TFA in acetonitrile) is run on an HPLC (Waters) over 120 minutes at 10 mL/minute while monitoring the UV at 280 nm (4.0 A) and collecting one minute fractions. Appropriate fractions are combined, frozen and lyophilized. Dried products are analyzed by HPLC (0.46 x 15 cm METASIL AQ C 18) and MALDI mass spectrometry.
Example 2 - Preparation of the Selective VPAC2 Receptor Peptide Agonists by Solid Phase FMoc Chemistry:
Approximately 114 mg (50 mMole) FMOC Ser(tBu) WANG resin (purchased from GlycoPep, Chicago, EL) is placed in each reaction vessel. The synthesis is conducted on a Rainin Symphony Peptide Synthesizer. Analogs with a C-terminal amide are prepared using 75 mg (50 μmole) Rink Amide AM resin (Rapp Polymere. Tuebingen, Germany).
The following FMOC amino acids are purchased from GlycoPep (Chicago, IL), and NovaBiochem (La Jolla, CA): Arg-2,2,4,6,7-pentamethyldihydrobenzofuran-5- sulfonyl (Pbf), Asn-trityl (TA)1 Asp-β-t-Butyl ester (tBu), Glu-δ-t-butyl ester (tBu), GIn- trityl (TA), His-trityl (TA), Lys-t-butyloxycarbonyl (Boc), Ser-t-butyl ether (OtBu), Thr-t- butyl ether (OtBu), Trp-t-butyloxycarbonyl (Boc), Tyr-t-butyl ether (OtBu). Solvents dimethylformamide (DMF-Burdick and Jackson), N-methyl pyrrolidone (NMP-Burdick and Jackson), dichloromethane (DCM-Mallinkrodt) are purchased from Mays Chemical Co. (Indianapolis, IN).
Hydroxybenzotriazole (HOBt), di-isopropylcarbodiimide (DIC), di- isopropylethylamine (DJJEA), and piperidine (Pip) are purchased from Aldrich Chemical Co (Milwaukee, WI).
AU amino acids are dissolved in 0.3 M in DMF. Three hour DIC/HOBt activated couplings are run after 20 minutes deprotection using 20% Piperidine/DMF. Each resin is washed with DMF after deprotections and couplings. After the last coupling and deprotection, the peptidyl resins are washed with DCM and are dried in vacuo in the reaction vessel. For N-terminal acylation, four-fold excess of symmetric anhydride of the corresponding acid is added onto the peptide resin. The symmetric anhydride is prepared by DIC activation in DCM. The reaction is allowed to proceed for 4 hours and monitored by ninhydrin test. The peptide resin is then washed with DCM and dried in vacuo. The cleavage reaction is mixed for 2 hours with a cleavage cocktail consisting of
0.2 mL thioanisole, 0.2 mL methanol, 0.4 mL triisopropylsilane, per 10 mL TFA, all purchased from Aldrich Chemical Co., Milwaukee, WI. If Cys is present in the sequence, 2% of ethanedithiol is added. The TFA filtrates are added to 40 mL ethyl ether. The precipitants are centrifuged 2 minutes at 2000 rpm. The supematants are decanted. The pellets are resuspended in 40 mL ether, re-centrifuged, re-decanted, dried under nitrogen and then in vacuo.
0.3-0.6 mg of each product is dissolved in 1 mL 0.1% TFA/acetonitrile(ACN), with 20 μL being analyzed on HPLC [0.46 x 15cm METASIL AQ C18, lmL/min, 45C°, 214 nM (0.2A), A=0.1%TFA, B=0.1%TFA/50%ACN. Gradient = 50% B to 90% B over 30 minutes].
Purifications are run on a 2.2 x 25 cm VYDAC C18 column in buffer A (0.1% TFA in water). A gradient of 20% to 90% B (0.1% TFA in acetonitrile) is ran on an HPLC (Waters) over 120 minutes at 10 mL/minute while monitoring the UV at 280 nm (4.0A) and collecting 1 minute fractions. Appropriate fractions are combined, frozen and lyophilized. Dried products are analyzed by HPLC (0.46 x 15 cm METASJJL AQ C 18) and MALDI mass spectrometry. P442: Synthesis is carried out using the FMoc protocols described above. P442 is characterised by analytical HPLC: tR = 10.8rnin, HPLC conditions as described above, and MALDI-TOF: calculated m/z = 4273.9, measured m/z = 4274.9 [M+H1"]. After purification using reversed-phase preparative HPLC, pure fractions are combined and lyophilised: 5.4mg is obtained as a final lyophilised powder.
P520: As described for P442. Analytical HPLC: tR= 10.9 min. MALDI-TOF: calculated m/z = 4290.0, measured m/z = 4290.8 [MH-H+]. 14.8mg is obtained as a final lyophilised powder.
P524: As described for P442. Analytical HPLC: tR= 11.0 min. MALDI-TOF: calculated m/z = 4288.0, measured m/z = 4288.8 [MH-H+]. 18.7mg is obtained as a final lyophilised powder.
P574: As described for P442. Analytical HPLC: tR = 11.7 min. MALDI-TOF: calculated m/z = 4330.1, measured m/z = 4330.7 [MH-H+]. 46.2mg is obtained as a final lyophilised powder.
Example 3 - In-vitro potency at human VPAC2 receptors:
DiscoveRx: A CHO-S cell line stably expressing human VPAC2 receptor in a 96- well microtiter plate is seeded with 50,000 cells/well the day before the assay. The cells are allowed to attach for 24 hours in 200 μ,L culture medium. On the day of the experiment, the medium is removed. Also, the cells are washed twice. The cells are incubated in assay buffer plus IBMX for 15 minutes at room temperature. Afterwards, the stimuli are added and are dissolved in assay buffer. The stimuli are present for 30 minutes. Then, the assay buffer is gently removed. The cell lysis reagent of the DiscoveRx cAMP kit is added. Thereafter, the standard protocol for developing the cAMP signal as described by the manufacturer is used (DiscoveRx Inc., USA). EC50 values for cAMP generation are calculated from the raw signal or are based on absolute cAMP levels as determined by a standard curve performed on each plate. In the case of the VPACl receptor, CHO-PO cells are transiently transfected with human VPACl receptor DNA using commercially available transfection reagents (Lipofectamine from Invitrogen). The cells are seeded at a density of 10,000/well in a 96-well plate and are allowed to grow for 3 days in 200 mL culture medium. At day 3, the assay described above for the VPAC2 receptor cell line is performed. Results for each agonist are the mean of two independent runs. VPACl results are only generated using the DiscoveRx assay. The typically tested concentrations of peptide are: 1000, 300, 100, 10, 1, 0.3, 0.1, 0.01, 0.001, 0.0001 and 0 nM.
Alpha screen: Cells are washed in the culture flask once with PBS. Then, the cells are rinsed with enzyme free dissociation buffer. The dissociated cells are removed. The cells are then spun down and washed in stimulation buffer. For each data point, 50,000 cells suspended in stimulation buffer are used. To this buffer, Alpha screen acceptor beads are added along with the stimuli. This mixture is incubated for 60 minutes. Lysis buffer and Alpha screen donor beads are added and are incubated for 60 to 120 minutes. The Alpha screen signal (indicative of intracellular cAMP levels) is read in a suitable instrument (e.g. AlphaQuest from Perkin-Elmer). Steps including Alpha screen donor and acceptor beads are performed in reduced light. The EC50 for cAMP generation is calculated from the raw signal or is based on absolute cAMP levels as determined by a standard curve performed on each plate. Results for each agonist are, at minimum, from two analyses performed in a single run. For some agonists, the results are the mean of more than one run. The tested peptide concentrations are: 10000, 1000, 100, 10, 3, 1, 0.1, 0.01, 0.003, 0.001, 0.0001 and 0.00001 nM.
The activity (EC50 (nM)) for the human VPAC2 and VPACl receptors is reported in Table 1.
Table 1
Figure imgf000060_0001
Figure imgf000061_0001
1MeBn of two or more independent runs
2Single result from two analyses performed in a single run. Some values represent the average of more than one such experiment.
Example 4 - Selectivity:
Binding assays: Membrane prepared from a stable VPAC2 cell line (see Example 3) or from cells transiently transfected with human VPACl or PACl are used. A filter binding assay is performed using 1251-labeled VIP for VPACl and VPAC2 and 1251- labeled PACAP-27 for PACl as the tracers.
For this assay, the solutions and equipment include:
Presoak solution: 0.5 % Polyethyleneamine in Aqua dest Buffer for flushing filter plates: 25 mM HEPES pH 7.4
Blocking buffer: 25 mM HEPES pH 7.4; 0.2 % protease free BSA
Assay buffer: 25 mM HEPES pH 7.4; 0.5 % protease free BSA
Dilution and assay plate: PS-Microplate, U form
Filtration Plate: Multiscreen FB Opaque Plate; 1.0 μM Type B Glasfiber filter
In order to prepare the filter plates, the presoak solution is aspirated by vacuum filtration. The plates are flushed twice with 200 μL flush buffer. 200 μL blocking buffer is added to the filter plate. The filter plate is then incubated with 200 μL presoak solution for 1 hour at room temperature.
The assay plate is filled with 25 μL assay buffer, 25 μL membranes (2.5 μg) suspended in assay buffer, 25 μL compound (agonist) in assay buffer, and 25 μL tracer (about 40000 cpm) in assay buffer. The filled plate is incubated for 1 hour with shaking. The transfer from assay plate to filter plate is conducted. The blocking buffer is aspirated by vacuum filtration and washed two times with flush buffer. 90 μL is transferred from the assay plate to the filter plate. The 90 μL transferred from assay plate is aspirated and washed three times with 200 μL flush buffer. The plastic support is removed. It is dried for 1 hour at 60 °C. 30 μL Microscint is added. The count is performed. The selectivity (IC50) for human VPAC2, VPACl, and PACl is reported in Table
2. Table 2
Figure imgf000062_0001
Figure imgf000063_0001
Example 5 - In vitro potency at rat VPACl and VPAC2 receptors:
DiscoveRx: CHO-PO cells are transiently transfected with rat VPACl or VPAC2 receptor DNA using commercially available transfection reagents (Lipofectamine from Invitrogen). The cells are seeded at a density of 10,000/well in a 96-well plate and are allowed to grow for 3 days in 200 mL culture medium. At day 3, the assay is performed.
On the day of the experiment, the medium is removed. Also, the cells are washed twice. The cells are incubated in assay buffer plus IBMX for 15 minutes at room temperature. Afterwards, the stimuli are added and are dissolved in assay buffer. The stimuli are present for 30 minutes. Then, the assay buffer is gently removed. The cell lysis reagent of the DiscoveRx cAMP kit is added. Thereafter, the standard protocol for developing the cAMP signal as described by the manufacturer is used (DiscoveRx Inc., USA). EC5o values for cAMP generation are calculated from the raw signal or are based on absolute cAMP levels as determined by a standard curve performed on each plate. Results for each agonist are the mean of two independent runs. Rat VPACl and VPAC2 results are only generated using the DiscoveRx assay. The typically tested concentrations of peptide are: 1000, 300, 100, 10, 1, 0.3, 0.1, 0.01, 0.001, 0.0001 and O nM.
The activity (EC50 (nM)) for the rat VPAC2 and VPACl receptors is reported in
Table 3. Table 3
Figure imgf000064_0001
Figure imgf000065_0001
Example 6 - Serum Stability Studies:
In order to determine the stability of VPAC2 receptor peptide agonists in rat serum, CHO-VPAC2 cells clone #6 (96 well ρlates/50,000 cells/well and 1 day culture), PBS IX (Gibco), the peptides for the analysis in a 100 μM stock solution, rat serum from a sacrificed normal Wistar rat, aprotinin, and a DiscoveRx assay kit are obtained. The rat serum is stored at 40C until use and is used within two weeks.
On Day 0, two 100 μL aliquots of 10 μM peptide in rat serum are prepared by adding 10 μL peptide stock to 90 μL rat serum for each aliquot. 250 kIU aprotinin / niL is added to one of these aliquots. The aliquot is stored with aprotinin at 4°C. The aliquot is stored without aprotinin at 37°C. The aliquots are incubated overnight.
On Day 1, after overnight incubation of the aliquots prepared on day 0, an incubation buffer containing PBS + 1.3 mM CaCl2, 1.2 mM MgCl2, 2 mM glucose, and 0.25 mM IBMX is prepared. A plate with 11 serial 5X dilutions of peptide for the 4°C and 37°C aliquot is prepared for each peptide studied. 2000 nM is used as the maximal concentration if the peptide has an EC50 above 1 nM and 1000 nM as maximal concentration if the peptide has an EC5O below 1 nM from the primary screen (see Example 3). The plate(s) are washed with cells twice in incubation buffer. The plates are allowed to hold 50 μL incubation media per well for 15 minutes. 50 μL solution per well is transferred to the cells from the plate prepared with 11 serial 5X dilutions of peptide for the 4°C and 370C aliquot for each peptide studied, using the maximal concentrations that are indicated by the primary screen, in duplicate. This step dilutes the peptide concentration by a factor of two. The cells are incubated at room temperature for 30 minutes. The supernatant is removed. 40 μL/well of the DiscoveRx antibody/extraction buffer is added. The cells are incubated on the shaker (300 rpm) for 1 hour. Normal procedure with the DiscoveRx kit is followed. cAMP standards are included in column 12. EC50 values are determined from the cAMP assay data. The remaining amount of active peptide is estimated by the formula EC50, 4c/EC50, 37c-
Estimated peptide stabilities are shown in table 4 below. Table 4
Figure imgf000066_0001
Serum stability in human serum may also be determined using the above described protocol substituting rat serum for human serum (Eg. Sigma # H-4522, Lot # 043 K0500).
The estimated amounts of peptide (%) remaining after 24h incubation at 37°C in human serum are listed in table 5 below. Table 5
Figure imgf000066_0002
Example 7 - Comparison of the interaction of the VPAC2 receptor peptide agonists of the present invention with the recombinant rat VPACl, VPAC2 and PACl receptors expressed in CHO cells: The peptide samples are stored frozen and thawed prior to the assay. Reference compounds (e.g. VIP and the tracers) are not stored frozen. All peptide sample and reference compound dilutions are performed in PBS. Peptides solutions are kept in the cold room for four days. Stock solutions are stored at -8O0C. New dilution curves are prepared every week. All studies are performed on crude membranes prepared from three different cell cultures expressing the different recombinant receptors, using methodology that is known in the literature. Duplicate values are obtained for each assay.
The selectivity of the VPAC2 receptor peptide agonists of the present invention are tested on the rat VPACl and VPAC2 receptors recombinantly expressed in CHO cells. The compounds of the invention were evaluated in receptor binding and adenylate cyclase activation assays.
Competition binding curves from 10"11 to 10"5M (two concentrations per log) of unlabelled peptide using 125I-VIP (VPACl-R) and 125I-RO 25-1553 (VPAC2-R) as tracers; incubations performed at 250C for 30 minutes. In each series of assays, unlabelled VIP and RO 25-1553 are used as standards. Each assay is done in duplicate and performed on two different membrane preparations.
Dose-effect curves of adenylate cyclase activation are generated using the VPAC2 receptor peptide agonists (10"π to 10"6M, two concentrations per log) of the present invention. Adenylate cyclase activity is determined by the procedure of Salomon et al., a highly sensitive adenylate cyclase assay {Analytical Biochemistry 58 (1974)). Membrane proteins (3-15 g) are incubated in a total volume of 60 1 containing 0.5 mM [32p]-ATP, 10 M GTP, 5 mM MgCl2, 0.5 mM EGTA, 1 mM cAMP, 1 mM theophylline, 10 mM phospho(enol)pyruvate, 30 g/ml pyruvate kinase and 30 mM Tris-HCl at a final pH of 7.8. The reaction is initiated by membrane addition and is terminated after 15 min incubation at 37 0C by addition of 0.5 ml of 0.5 % sodium dodecyl-sulfate solution containing 0.5 mM ATP, 0.5 mM cAMP and 20,00Og [3H]-cAMP. cAMP was separated from ATP by two successive chromatographies on Dowex 50Wx8 and neutral alumina.
Example 8 - In vivo assays: Intravenous glucose tolerance test (IVGTT): Normal Wistar rats are fasted overnight and are anesthetized prior to the experiment. A blood sampling catheter is inserted into the rats. The compound is given in the jugular vein. Blood samples are taken from the carotid artery. A blood sample is drawn immediately prior to the injection of glucose along with the compound. After the initial blood sample, glucose mixed with compound is injected intravenously (i.v.). A glucose challenge of 0.5 g/kg body weight is given, injecting a total of 1.5 mL vehicle with glucose and agonist per kg body weight. The peptide concentrations are varied to produce the desired dose in μg/kg. Blood samples are drawn at 2, 4, 6 and 10 minutes after giving glucose. The control group of animals receives the same vehicle along with glucose, but with no compound added. In some instances, a 30 minute post-glucose blood sample is drawn. Aprotinin is added to the blood sample (250 kIU/ml blood). The serum is then analyzed for glucose and insulin using standard methodologies.
The assay uses a formulated and calibrated peptide stock in PBS. Normally, this stock is a prediluted 100 μM. stock. However, a more concentrated stock with approximately 1 mg agonist per mL is used. The specific concentration is always known. Variability in the maximal response is mostly due to variability in the vehicle dose. Protocol details are as follows:
Figure imgf000068_0001
Figure imgf000069_0001
Delayed IVGTT: Perform IVGTT as described above, making the following changes. After the initial blood sample, compound or vehicle is injected i.v. Glucose is injected i.v. 30 minutes later in a separate injection. Blood samples are taken immediately prior to administration of the compound, at 15 minutes after administration of the compound, and at 30 minutes after administration of the compound. The sample at 30 minutes after administration of the compound is taken immediately prior to glucose administration. Blood samples are drawn 2, 4, 6, 10, and 30 minutes after giving glucose (i.e. 32, 34, 36, 40 and 60 minutes after compound administration). The blood samples at 15 and 60 minutes are not essential to the study and not always taken. Aprotinin is added to the blood sample (250 klU/ml blood). The serum is then analyzed for glucose and insulin using standard methodologies.
The assay uses a formulated and calibrated peptide stock in PBS. Normally, this stock is a prediluted 100 μM stock. However, a more concentrated stock with approximately 1 mg agonist per mL is used. The specific concentration is always known.
Oral Glucose Tolerance Test (OGTT):
The effect of a selective VPAC2 receptor peptide agonist on plasma insulin and glucose is evaluated during OGTT in conscious Wistar rats. The maximal dose of agonist is 10 μg/kg. Since the peptide is given intravenously and has a very short half-life, a delay between glucose and compound administrations is applied. Protocol details are as follows:
Figure imgf000069_0002
Figure imgf000070_0001
Example 9 - Pharmacokinetic Assay:
An analysis of active peptide levels in rat plasma is conducted after IV injection of 10 μg/kg of each peptide. An IVGTT with glucose is given immediately after T = 0 to 6 animals per condition. Samples are taken at 0, 2, 4, 6, and 10 minutes after injection.
For cell handling, 50,000 cells / well are plated and kept in culture over night. Cells are washed twice in PBS and 50 μl/well stimulation medium consisting of PBS + 1.2 MgCl2, 1.3 CaCl2, 2 glucose and 0.5 IBMX is added. The plate is incubated for 15 minutes and 50 μl/well of the plasma samples is added. The plate is incubated for 30 minutes, the supernatant is removed and normal procedure with the DiscoveRx assay is followed. Plates are prepared in duplicate. Protease and peptidase inhibitor are present in all plasma samples.
Example 10 - DPP-IV HPLC Assays: P art 1: Formulation of selective VPAC2 receptor peptide agonists: Approximately 2 mg of lyophilized peptide is weighed and dissolved in approximately 1.6 mL de-ionized water. If the peptide does not dissolve, the pH is adjusted with IM NaOH to between pH 10.0 and 10.5. After incubation at room temperature for 30 minutes, l/10th of the original volume 10 x PBS is added. The pH is adjusted to between pH 7.2 and 7.6. The peptide solution is filtered through a 0.22 μm Millex-GV syringe filter (Millipore, Bedford MA, USA). The peptide concentration is determined through absorption at 280 nm. The peptide concentration is then adjusted to 100 μM. The peptides are frozen at -20°C for further use.
Part 2: In vitro incubation of selective VPAC2 receptor peptide agonists with purified Dipeptidyl-peptidase IV (DPP-IV):
The stability of selective VPAC2 receptor peptide agonists against proteolysis by DPP-IV is determined using 100 μL of a 100 μM peptide solution in 1 x PBS. A 10 μL solution is removed and quenched with 40 μL of 0.1% trifluoroacetic acid (TFA)/ 20% acetonitrile (ACN). This solution (20 μL) is analyzed by re versed-phase HPLC. The re versed-phase analysis consists of a Zorbax 300SB-C8 column (3.5 micron, 4.6x50mm, Alltech Associates, Inc., Deerfield IL, USA) running a 15-40%B gradient over 15 minutes at 6O0C where A-buffer is 0.1%(v/v) TFA in water and B-buffer is 0.085%(v/v) TFA in ACN. The peak area is integrated. This peak area serves as an internal control as 100% intact peptide.
A 10 μL aliquot of a 1.12 mU/μL solution of DPP-IV (Sigma, St. Louis, LO, USA) is added to 90 μL of a 100 μM solution of peptide, resulting in a substrate concentration of 90 μM peptide. The reaction mixture is then stored at 37°C. At various time-points, 10 μL of solution is removed, quenched with 40 μL 0.1% TFA/ 20% ACN, and analyzed by reversed-phase HPLC as described above. The remaining full length peptide concentration (nM) at each timepoint, except time = 0, is calculated using following formula: peak area [time xl * concentration FtOl peak area [time O]* 0.9 For the time = 0 timepoint, the concentration (nM) is calculated using the following formula: peak area ["time xl * initial substrate concentration \9 nMI peak area [time 0]
Other modifications of the present invention will be apparent to those skilled in the art without departing from the scope of the invention.

Claims

1. A VPAC2 receptor peptide agonist comprising a sequence selected from:
SEQ ID NO: 17 HSDAVFTEQY(OMe)TRAibRAibQLAAAibOrn Y(OMe)LQSIK
AibOrn; SEQ ID NO: 18 HSDAVFTEK(CO(CH2)2SH)Y(OMe)TOrnLRAibQVAAAibOrn
YLQSIOrnOrn; SEQ ID NO: 19 HSD A VFTEQY(OMe)TOrnLRAibQVAAAibOrn YLQSIOmK(W)
Orn; SEQ ID NO: 20 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibK(CO(CH2)2SH)YLQ
SlOrnOrn;
SEQ ID NO: 21 HSDAVFTEQY(OMe)TOrnLRAibQVAAK(CO(CH2)2SH)OrnYLQ SlOrnOrn;
SEQ ID NO: 22 HSD AVFTEQY(OMe)TOrnLRAibQVCAAibOrn YLQSIOrnOrn; SEQ ID NO: 23 HSD AVFTEQY(OMe)TOrnLRCQVAAAibOrn YLQSIOrnOrn; SEQ ID NO: 24 HSD A VFTEQY(OMe)TOrnLRAibQLAAAibOrn YLQSIOrnOrn; SEQ ID NO: 25 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYAibQSIOrnOrn; SEQ ID NO: 26 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQAibIOrnOrn; SEQ BD NO: 27 HSDAVFTEQY(OMe)TOrnLRAibQVAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 28 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQAibIOrnOrn; SEQ ID NO: 29 HSDA VFTEQ Y(OMe)TOrnLRAibQLAAAibOrnYAibQAibIOmOrn; SEQ ID NO: 30 HSD AVFTEQ Y(OMe)TOrnLRAibQLAAbuAibOrnYAibQSIOrnOrn; SEQ ID NO: 31 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQSIOrnOrn; SEQ ID NO: 32 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYAibQAibIOrn
Orn;
SEQ ID NO: 33 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYAibQSIOrnOrn; SEQ ID NO: 34 HSD A VFTEQY(OMe)TOrnLRK(W)QVAAAibOrn YLQSIOrnOrn; SEQ ID NO: 35 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLK(W)SIOrnOrn; SEQ ID NO: 36 HSDA VFTEQY(OMe)TOrnLRAibQK(W)AAAibOrn YLQSIOrnOrn; SEQ ID NO: 37 HSDAVFTEQY(OMe)TOrnLRK(CO(CH2)2SH)QVAAAibOrnYLQ SIOmOm:
SEQ ID NO: 38 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibK(W)YLQSIOmOrn; SEQ ID NO: 39 HSDAVFTEQY(OMe)TOmLRAibQVAAAibCYLQSIOrnOrn; SEQ ID NO: 40 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 41 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLQSK(W)OrnOrn; SEQ ID NO: 42 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQAibIOmC
Om; SEQ ID NO: 43 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQAibCOrn
Om; SEQ ID NO: 44 HSDAVFTEQY(OMe)TOmLRAibQCAAbuAibOmYLQAibIOmOm; SEQ ID NO: 45 HSDAVFTEQY(OMe)TOmLRCQLAAbuAibOrnYLQAibIOrnOrn; SEQ ID NO: 92 HSDAVFTEQY(OMe)TOmLRAibQVK(CO(CH2)2SH)AAibOm
YLQSIOmOm;
SEQ ID NO: 93 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOrnYLQSIOrnCOrn; SEQ ID NO: 94 HSD A VFTEQY(OMe)TOmLRAibQLAAbuAibOm YLQSCOmOm; SEQ ID NO: 95 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrn
K(CO(CH2)2SH)Om; SEQ ID NO: 96 HSDAVFTEQY(OMe)TOmLRAibQLAAbuAibOmYLQSIOm
K(CO(CH2)2SH)Orn; SEQ ID NO: 97 HSDA VFTEQ Y(OMe)TOrnLRK(W)QLAAbuAibOrnYLQAibIOrn
Om;
SEQ ID NO: 98 HSDAVFTEQY(OMe)TOrnLRAibQLAAAibOrnYLQSIOrnOrnC; SEQ ID NO: 99 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOmYLQSIOmOmC; SEQ ID NO: 100 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQSIOrnOrnC; SEQ ID NO: 101 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQAibI
OmOm; SEQ ID NO: 102 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQAibI
OmCOm;
SEQ ID NO: 103 HSD A VFTEQY(OMe)TOrnLRAibQCAAbuAibOrn Y(OMe)LQAM OmOm;
SEQ ID NO: 104 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnYLQAibIOrn
OmC; SEQ ID NO: 105 HSD A VFTEQ Y(OMe)TOrnLRAibQLAAbuAibOrn Y(OMe)LQSI OrnOrn;
SEQ ID NO: 106 HSDAVFTEQY(OMe)TOrnLRAibQCAAbuAibOmY(OMe)LQSI
OrnOrn; SEQ ID NO: 107 HSDAVFTEQY(OMe)TOrnLRAibQLAAbuAibOrnY(OMe)LQSI
OrnCOrn;
SEQ ID NO: 108 HSDAVFTEQ Y(OMe)TOrnLRAibQLAbuAAibOrnYLQSIOrnOrn;
SEQ ID NO: 109 HSDAVFTEQY(OMe)TOrnLRAibQK(CO(CH2)2SH)AAbu
AibOrn YLQ AibIOrnOrn ; SEQ ID NO: 110 HSDAVFTEQY(OMe)TOrnLRAibQK(W)AAbuAibOrnYLQ
AibIOrnOrn;
SEQ ID NO: 145 HSDAVFTDNYTRLRKQVAAKKYLQSIKNKRQ;
SEQ ID NO: 146 HSDAVFTDNYTLLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 147 HSDAVFTDNYTQLRAibQVAAAibKYLQSIOrnNOrn; SEQ ID NO: 148 HSDAVFTDNYTFLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 149 HSDAVFTDNYTOrnLRAibQVAAAibKYLQCIOrnNOrn;
SEQ ID NO: 150 HSDAVFTDNYTOrnLRAibQVAACOrnYLQSIOrnNOrn;
SEQ ID NO: 151 HSDAVFTDNYTOrnLRAibQVAAAibKYLQSSOrnNOrn;
SEQ ID NO: 152 HSDAVFTDNYTOrnLRAibQVAAAibKYLSSIOrnNOrn; SEQ DD NO: 153 HSDAVFTDNYTOrnLRAibQVAAAibKYSQSIOrnNOrn;
SEQ ID NO: 154 HSDAVFTDNYTOrnLRAibQVAAAibKSLQSIOrnNOrn;
SEQ ID NO: 155 HSDAVFTDNYTOrnLRAibQVAAAibSYLQSIOrnNOrn;
SEQ ID NO: 156 HSDAVFTDNYTOrnLRAibQVSAAibKYLQSIOrnNOrn;
SEQ ID NO: 157 HSDAVFTDNYTOrnLRAibQSAAAibKYLQSIOrnNOrn; SEQ ID NO: 158 HSDAVFTDNYTOrnLRAibSVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 159 HSDAVFTDNYTOmSRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 160 HSDAVFTDSYTOrnLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 161 HSDAVFTDNYThRLRAibQVAAAibKYLQSIKNKRY;
SEQ ID NO: 162 HSDAVFTDNYTRLRAibQVAAAibKYLQSIKAibOrn; SEQ ID NO: 163 HSDAVFTDNY(OMe)TRLRAibQVAAAibKYLQSIKNKRY;
SEQ ID NO: 164 HSEAVFTENYTOrnLRAibQVAAAibKYLQSIOrnNOrn;
SEQ ID NO: 165 HSDAVFTDQYTOrnLRAibQVAAAibKYLQSIOrnQOrn; SEQ ID NO: 166 HSDAVFTDNYTRLLAKLALQKYLQSIOrnNOrn;
SEQ ID NO: 167 HSDAVFTDNYTOrnLLAKLALQKYLQSIOmNOrn;
SEQ ID NO: 168 HSEAVFTEQYTOrnLRAibQVAAAibOmYLQSIOrnOrn;
SEQ ID NO: 169 HSDA VFTDNYTOrnLRAibQ VAS AibKYLQSIOrnNOrn; SEQ K) NO: 170 HSEAVFTEQY(OMe)TOmLRAibQLAAAibOmYLQSIOmOrn;
SEQ ID NO: 171 HSDAVFTDQY(OMe)TOrnLRAibQLAAAibOmYLQSIOmOrn;
SEQ ID NO: 172 HSDAVFTDQYTOrnLRAibQLAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 173 HSDAVFTDQYTOmLRAibQVAAAibOrnYLQSIOrnOrn;
SEQ ID NO: 174 HSDAVFTDNYTOrnLRAibQVAAAibOrnYLQSIOrnOrn; SEQ ID NO: 175 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOmYLQSIOrnOrn;
SEQ ID NO: 176 HSDAVFTDNYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ ID NO: 177 HSDAVFTDQYTRAibRAibQVAAAibKYLQSIKAibK;
SEQ ID NO: 178 HSDAVFTDQYTRAibRAibQLAAAibKYLQSIKAibK;
SEQ DD NO: 179 HSDAVFTDQY(OMe)TRAibRAibQLAAAibKYLQSIKAibK; SEQ ID NO: 180 HSEA VFTEQ Y(OMe)TRAibRAibQLAAAibKYLQSIKAibK;
SEQ ID NO: 181 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOmYLCSIOmOrn;
SEQ ID NO: 182 HSDAVFTEQY(OMe)TOmLRAIbQ VAAAibOm YL K(CO(CH2)2SH)SIOrnOrn;
SEQ K) NO: 183 HSDAVFTEQY(OMe)TOrnLRAibQVACAibOrnYLQSIOrnOrn; SEQ ID NO: 184 HSDAVFTEQ Y(OMe)TOrnLRAibQVAK(CO(CH2)2SH)AibOrn
YLQSIOrnOrn;
SEQ ID NO: 185 HSDAVFTEQY(OMe)TOmLRAibCVAAAibOm YLQSIOrnOrn;
SEQ ID NO: 186 HSDAVFTDNYTOmLRK(W)QVAAAIbKYLQSIOmNOm;
SEQ ID NO: 187 HSD AVFTEQ Y(OMe)TOrnLRAibQLAAAibOrn Y(OMe)LQ SIOmOm;
SEQ ID NO: 188 HSDA VFTEQ Y(OMe)TOrnLRAibQVAAAibOrn YLQSCOmOm;
SEQ K) NO: 189 HSD AVFTEQY(OMe)TOrnLRAibQCAAAibOrn YLQSIOmOm;
SEQ K) NO: 190 HSDAVFTEQ Y(OMe)TOrnLRAibQVAAAibOrn YLQSIOmCOm;
SEQ K) NO: 191 HSDA VFTEQY(OMe)TOrnLRAibQVAAAibOrn YLQCIOmOm; SEQ K) NO: 192 HSDAVFTECY(OMe)TOrnLRAibQVAAAibOrnYLQSIOrnOrn;
SEQ K) NO: 193 HSDA VFTEQY(OMe)TOmCRAibQVAAAibOrn YLQSIOmOm;
SEQ K) NO: 194 HSDAVFTEQY(OMe)TOmLRAibQVAAAibOrnYLQS K(C0(CH2)2SH)0rn0rn; SEQ ID NO: 195 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOrnYLQ
K(CO(CH2)2SH)IOrnOrn;
SEQ ID NO: 196 HSDA VFTEQ Y(OMe)TOrnLRAibQK(CO(CH2)2SH)AAAibOrn YL QSIOrnOrn;
SEQ ID NO: 197 HSDAVFTEQY(OMe)TOmLRAibK(CO(CH2)2SH)VAAAibOrnY
LQSIOmOm; SEQ ID NO: 198 HSDAVFTEQY(OMe)TOrnLRAibQVAAAibOmYLQSIOrn
K(CO(CH2)2SH)Orn; SEQ ID NO: 199 HSDAVFTEQY(OMe)TOrnK(CO(CH2)2SH)RAibQVAAAibOrn
YLQSIOmOm;
and a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide sequence and wherein the C-terminal extension comprises an amino acid sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaa10'Xaa11-Xaa12 Formula 3 (SEQ ID NO: 3) wherein:
Xaai is: GIy, Cys, or absent; Xaa2 is: GIy, Arg, or absent;
Xaa3 is: Pro, Thr, or absent;
Xaa4 is: Ser, or absent;
Xaa5 is: Ser, or absent;
Xaa6 is: GIy, or absent; Xaa7 is: Ala, or absent;
Xaa8 is: Pro, or absent;
Xaa9 is: Pro, or absent;
Xaa10 is: Pro, or absent;
Xaaπ is: Ser, Cys, or absent; and Xaa12 is: Cys, or absent; wherein at least five of Xaa] to Xaa12 of the C-terminal extension are present and wherein if Xaal5 Xaa2, Xaa3, Xaa4, Xaas, Xaa6, Xaa7, Xaag, Xaa9, Xaaio, or Xaaπ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
2. A VPAC2 receptor peptide agonist according to claim 1 wherein the C- terminal extension is selected from:
Figure imgf000078_0001
3. A VPAC2 receptor peptide agonist according to any one of the preceding claims further comprising a N-terminal modification at the N-terminus of the peptide agonist wherein the N-terminal modification is selected from:
(a) addition of D-histidine, isoleucine, methionine, or norleucine;
(b) addition of a peptide comprising the sequence Ser-Trp-Cys-Glu-Pro-Gly-Trp-Cys- Arg (SEQ ID NO: 91)wherein the Arg is linked to the N-terminus of the peptide agonist;
(c) addition of C1-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3;
(d) addition Of -C(O)R1 wherein R1 is a C1-Ci6 alkyl optionally substituted with one or more substituents independently selected from aryl, C1-C6 alkoxy, -NH2, -OH, halogen, -SH and -CF3; an aryl optionally substituted with one or more substituents independently selected from C1-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; an aryl C1-C4 alkyl optionally substituted with one or more substituents independently selected from Ci-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; -NR2R3 wherein R2 and R3 are independently hydrogen, C1-C6 alkyl, aryl or aryl C1-C4 alkyl; -OR4 wherein R4 is Ci-C16 alkyl optionally substituted with one or more substituents independently selected from aryl, Ci-C6 alkoxy, -NH2, -OH, halogen and -CF3, aryl optionally substituted with one or more substituents independently selected from Ci-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, Ci-C6 alkoxy, -NH2, -OH, halogen and -CF3, or aryl C1-C4 alkyl optionally substituted with one or more substituents independently selected from Ci-C 6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C1-C6 alkoxy, -NH2, -OH, halogen and -CF3; or 5- pyrrolidin-2-one; (e) addition of -SO2R5 wherein R5 is aryl, aryl Ci-C4 alkyl or Ci-C16 alkyl;
(f) formation of a succinimide group optionally substituted with C1-C 6 alkyl or -SR6, wherein R6 is hydrogen or C1-C 6 alkyl;
(g) addition of methionine sulfoxide;
(h) addition of biotinyl-6-aminohexanoic acid (6-aminocaproic acid); and (i) addition of -C(=NH)-NH2.
4. A VPAC2 receptor peptide agonist according to claim 3 wherein the N- terminal modification is the addition of a group selected from: acetyl, propionyl, butyryl, pentanoyl, hexanoyl, methionine, methionine sulfoxide, 3-phenylpropionyl, phenylacetyl, benzoyl, norleucine, D-histidine, isoleucine, 3-mercaptopropionyl, biotinyl-6- aminohexanoic acid (6-aminocaproic acid), and -C(=NH)-NH2.
5. A VPAC2 receptor peptide agonist according to claim 4 wherein the N- terminal modification is the addition of acetyl or hexanoyl.
6. A VPAC2 peptide receptor agonist according to claim 1 comprising an amino acid sequence selected from:
Figure imgf000079_0001
Figure imgf000080_0001
Figure imgf000081_0001
Figure imgf000082_0001
Figure imgf000083_0001
Figure imgf000084_0001
Figure imgf000085_0001
Figure imgf000086_0002
7. . VPAC2 receptor peptide agonist comprising a sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Thr-Xaag-Xaa9-Xaa10-Thr-Xaa12-Xaa13- Xaa14-
Figure imgf000086_0001
-Abu-Xaa20-Xaa21-Xaa22- Xaa23-Xaa24-Xaa25-Xaa26- Xaa27-Xaa2s-Xaa29-Xaa3o-Xaa31-Xaa32-Xaa33-Xaa34-Xaa35-Xaa36-Xaa37-Xaa38- Xaa39-Xaa4o
Formula 4 (SEQ ID NO: 4) wherein:
Xaaϊ is: His, dH, or is absent;
Xaa2 is: dA, Ser, VaI, GIy, Thr, Leu, dS, Pro, or Aib;
Xaa3 is: Asp or GIu;
Xaa4 is: Ala, He, Tyr, Phe, VaI, Thr, Leu, Trp, GIy, dA, Aib, or NMeA;
Xaa5 is: VaI, Leu, Phe, He, Thr, Trp, Tyr, dV, Aib, or NMeV; Xaa6 is: Phe, He, Leu, Thr, VaI, Tip, or Tyr;
Xaa8 is: Asp, GIu, Ala, Lys, Leu, Arg, or Tyr;
Xaa9 is: Asn, GIn, Asp, GIu, Ser, Cys, Lys, or K(CO(CH2)2SH);
Xaa10 is: Tyr, Trp, Tyr(OMe), Ser, Cys, or Lys; Xaa12 is: Arg, Lys, GIu, hR, Orn, Lys (isopropyl), Aib, Cit, Ala, Leu, GIn, Phe, Ser, or
Cys;
Xaa13 is: Leu, Phe, GIu, Ala, Aib, Ser, Cys, Lys, or K(CO(CH2)2SH);
Xaa14 is: Arg, Leu, Lys, Ala, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, Cit, Ser, or Cys;
Xaa15 is: Lys, Ala, Arg, GIu, Leu, hR, Orn, Lys (isopropyl), Phe, GIn, Aib, K(Ac), Cit, Ser, Cys, K(W), or K(CO(CH2)2SH);
Xaa16 is: GIn, Lys, GIu, Ala, hR, Orn, Lys (isopropyl), Cit, Ser, Cys, K(CO(CH2)2SH), or
K(W);
Xaaπ is: VaI, Ala, Leu, lie, Met, NIe, Lys, Aib, Ser, Cys, K(CO(CH2)2SH), or K(W);
Xaa18 is: Ala, Ser, Cys, Lys, K(CO(CH2)2SH), K(W), Abu or NIe; Xaa2o is: Lys, GIn, hR, Arg, Ser, His, Orn, Lys (isopropyl), Ala, Aib, Trp, Thr, Leu, He,
Phe, Tyr, VaI, K(Ac), Cit, Cys, K(CO(CH2)2SH), or K(W);
Xaa21 is: Lys, His, Arg, Ala, Phe, Aib, Leu, GIn, Orn, hR, K(Ac), Cit, Ser, Cys, VaI, Tyr,
He, Thr, Trp, K(W), or K(CO(CH2)2SH);
Xaa22 is: Tyr, Trp, Phe, Thr, Leu, He, VaI, Tyr(OMe), Ala, Aib, Ser, Cys, Lys, K(W), or K(CO(CH2)2SH);
Xaa23 is: Leu, Phe, He, Ala, Trp, Thr, VaI, Aib, Ser, Cys, Lys, K(W), or K(CO(CH2)2SH);
Xaa24 is: GIn, GIu, Asn, Ser, Cys, Lys, K(CO(CH2)2SH), or K(W);
Xaa25 is: Ser, Asp, Phe, He, Leu, Thr, VaI, Trp, GIn, Asn, Tyr, Aib, GIu, Cys, Lys,
K(CO(CHa)2SH), or K(W); Xaa26 is: He, Leu, Thr, VaI, Trp, Tyr, Phe, Aib, Ser, Cys, Lys, K(CO(CH2)2SH), or K(W);
Xaa27 is: Lys, hR, Arg, GIn, Ala, Asp, GIu, Phe, GIy, His, He, Met, Asn, Pro, Ser, Thr,
VaI, Trp, Tyr, Lys (isopropyl), Cys, Leu, Orn, dK, K(W), or K(CO(CH2)2SH);
Xaa28 is: Asn, Asp, GIn, Lys, Arg, Aib, Orn, hR, Cit, Pro, dK, Ser, Cys, K(CO(CH2)2SH), or K(W); Xaa29 is: Lys, Ser, Arg, Asn, hR, Ala, Asp, GIu, Phe, GIy, His, He, Leu, Met, Pro, GIn,
Thr, VaI, Trp, Tyr, Cys, Orn, Cit, Aib, K(W), K(CO(CH2)2SH), or is absent; Xaa3o is: Arg, Lys, He, Ala, Asp, GIu, Phe, GIy, His, Leu, Met, Asn, Pro, GIn, Ser, Thr,
VaI, Trp, Tyr, Cys, hR, Cit, Aib, Orn, K(W), K(CO(CH2)2SH), or is absent;
Xaa31 is: Tyr, His, Phe, Thr, Cys, Ser, Lys, GIn, K(W), K(CO(CH2)2SH), or is absent;
Xaa32 is: Ser, Cys, Lys, or is absent; Xaa33 is: Trp or is absent;
Xaa34 is: Cys or is absent;
Xaa35 is: GIu or is absent;
Xaa3g is: Pro oris absent;
Xaa37 is: GIy or is absent; Xaa3s is: Trp or is absent;
Xaa39 is: Cys or is absent; and
Xaa40 is: Arg or is absent wherein if Xaa29, Xaa30, Xaa31, Xaa32, Xaa33, Xaa34, Xaa35, Xaa36, Xaa37, Xaa38, or Xaa39 is absent, the next amino acid present downstream is the next amino acid in the peptide agonist sequence, and a C-terminal extension wherein the N-terminus of the C-terminal extension is linked to the C-terminus of the peptide of Formula 4 and wherein the C-terminal extension comprises an amino acid sequence of the formula:
Xaa1-Xaa2-Xaa3-Xaa4-Xaa5-Xaa6-Xaa7-Xaa8-Xaa9-Xaa1o-Xaa11-Xaa12
Formula 3 (SEQ ID NO: 3) wherein:
X&Α\ is: GIy, Cys, or absent;
Xaa2 is: GIy, Arg, or absent; Xaa3 is: Pro, Thr, or absent;
Xaa4 is: Ser, or absent;
Xaas is: Ser, or absent;
Xaa6 is: GIy, or absent;
Xaa7 is: Ala, or absent; Xaa8 is: Pro, or absent;
Xaa9 is: Pro, or absent;
Xaa10 is: Pro, or absent; Xaaπ is: Ser, Cys, or absent; and Xaa12 is: Cys, or absent; wherein at least five of Xaai to Xaa12 of the C-terminal extension are present and wherein if Xaa1; Xaa2, Xaa3, Xaa4, Xaas, Xaa6, Xaa7, Xaa8, Xaag, Xaa10, or Xaaπ is absent, the next amino acid present downstream is the next amino acid in the C-terminal extension and wherein the C-terminal amino acid may be amidated.
8. A pharmaceutical composition comprising a VPAC2 receptor peptide agonist according to any one of claims 1 to 7 and one or more pharmaceutically acceptable diluents, carriers and excipients.
9. A VPAC2 receptor peptide agonist according to any one of claims 1 to 7 for use as a medicament.
10. The use of a VPAC2 receptor peptide agonist according to any one of claims 1 to 7 for the manufacture of a medicament for the treatment non-insulin- dependent diabetes.
11. The use of a VPAC2 receptor peptide agonist according to any one of claims 1 to 7 for the manufacture of a medicament for the treatment of insulin-dependent diabetes.
12. A method of treating diabetes in a patient in need thereof comprising administering a VPAC2 receptor peptide agonist according to any one of claims 1 to 7.
13. The method of claim 12 wherein the diabetes is non-insulin-dependent diabetes.
14. The method of claim 12 wherein the diabetes is insulin-dependent diabetes.
15. A pharmaceutical composition containing a VPAC2 receptor peptide agonist according to any one of claims 1 to 7 for treating non -insulin-dependent diabetes.
16. A pharmaceutical composition containing a VPAC2 receptor peptide agonist according to any one of claims 1 to 7 for treating insulin-dependent diabetes.
17. A VPAC2 receptor peptide agonist substantially as hereinbefore described with reference to the examples.
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