EP1250355A1 - Peptides chimeres de ciblage de la prostate comportant une activite pro-apoptotique - Google Patents

Peptides chimeres de ciblage de la prostate comportant une activite pro-apoptotique

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Publication number
EP1250355A1
EP1250355A1 EP01942640A EP01942640A EP1250355A1 EP 1250355 A1 EP1250355 A1 EP 1250355A1 EP 01942640 A EP01942640 A EP 01942640A EP 01942640 A EP01942640 A EP 01942640A EP 1250355 A1 EP1250355 A1 EP 1250355A1
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Prior art keywords
peptide
tumor
homing
seq
phage
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EP01942640A
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German (de)
English (en)
Inventor
Erkki I. Ruoslahti
Renata Pasqualini
Wadih Arap
Dale E. Bredesen
H. Michael Ellerby
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Sanford Burnham Prebys Medical Discovery Institute
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Sanford Burnham Prebys Medical Discovery Institute
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/04—Linear peptides containing only normal peptide links
    • C07K7/06—Linear peptides containing only normal peptide links having 5 to 11 amino acids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K47/00—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient
    • A61K47/50—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates
    • A61K47/51—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent
    • A61K47/62—Medicinal preparations characterised by the non-active ingredients used, e.g. carriers or inert additives; Targeting or modifying agents chemically bound to the active ingredient the non-active ingredient being chemically bound to the active ingredient, e.g. polymer-drug conjugates the non-active ingredient being a modifying agent the modifying agent being a protein, peptide or polyamino acid
    • A61K47/64—Drug-peptide, drug-protein or drug-polyamino acid conjugates, i.e. the modifying agent being a peptide, protein or polyamino acid which is covalently bonded or complexed to a therapeutically active agent
    • A61K47/6425—Drug-peptide, drug-protein or drug-polyamino acid conjugates, i.e. the modifying agent being a peptide, protein or polyamino acid which is covalently bonded or complexed to a therapeutically active agent the peptide or protein in the drug conjugate being a receptor, e.g. CD4, a cell surface antigen, i.e. not a peptide ligand targeting the antigen, or a cell surface determinant, i.e. a part of the surface of a cell
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P13/00—Drugs for disorders of the urinary system
    • A61P13/08—Drugs for disorders of the urinary system of the prostate
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
    • A61P31/04—Antibacterial agents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P35/00—Antineoplastic agents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
    • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
    • 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
    • C07K14/46—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates
    • 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
    • C07K14/46—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates
    • C07K14/47—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals
    • C07K14/4701—Peptides having more than 20 amino acids; Gastrins; Somatostatins; Melanotropins; Derivatives thereof from animals; from humans from vertebrates from mammals not used
    • C07K14/4723—Cationic antimicrobial peptides, e.g. defensins
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K7/00—Peptides having 5 to 20 amino acids in a fully defined sequence; Derivatives thereof
    • C07K7/04—Linear peptides containing only normal peptide links
    • C07K7/08—Linear peptides containing only normal peptide links having 12 to 20 amino acids
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K38/00—Medicinal preparations containing peptides
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07K—PEPTIDES
    • C07K2319/00—Fusion polypeptide

Definitions

  • the present invention relates generally to the fields of cancer biology and drug delivery and, more specifically, to the selective targeting of antimicrobial peptides to the prostate.
  • Prostatic adenocarcinoma recently became the most frequent cancer diagnosed in American men, surpassing the frequency of lung cancer for the first time. An estimated 30,000 American men die annually of this malignancy. Furthermore, prostate cancer affects men throughout the world, with the highest frequencies reported in the United States and Scandinavian countries and a moderately high frequency seen throughout Europe. Prostate cancer is a disease of elderly men, and of all patients with this disease, 75% are 60 to 80 years of age. At the age of 50 years, the estimated lifetime probability of developing clinically apparent prostatic carcinoma is about 10% for American men. However, autopsy studies have shown that the true frequency of prostatic carcinoma is actually considerably higher than is indicated by clinical evidence.
  • a major hurdle to advances in treating cancers such as cancer of the prostate is the relative lack of agents that can selectively target the cancer, while sparing normal tissue.
  • radiation therapy and surgery which generally are localized treatments, can cause substantial damage to normal tissue in the treatment field, resulting in scarring and, in severe cases, loss of function of the normal tissue.
  • Chemotherapy which generally is administered systemically, can cause substantial damage to organs such as bone marrow, mucosae, skin and the small intestine, which undergo rapid cell turnover and continuous cell division.
  • undesirable side effects for example, nausea, hair loss and reduced blood cell counts, occur as a result of systemically treating a cancer patient with chemotherapeutic agents.
  • Such undesirable side effects often limit the amount of a treatment that can be administered. Due to such shortcomings in treatment, cancer remains a leading cause of patient morbidity and death.
  • Naturally occurring antimicrobial peptides, and related synthetic antimicrobial sequences generally have an equivalent number of polar and nonpolar residues within an amphipathic domain and a sufficient number of basic residues to give the peptide an overall positive charge at neutral pH.
  • the biological activity of amphipathic ⁇ -helical peptides against Gram-positive bacteria may result from the ability of these peptides to form ion channels through membrane bilayers .
  • antimicrobial peptides selectively inhibit and kill bacteria while maintaining low mammalian cell cytotoxicity, with the differential sensitivity of bacterial cells apparently due to membrane differences between bacteria and mammalian cells. As shown herein, these antimicrobial peptides can be endowed with selective cytotoxic activity against a particular eukaryotic cell type, such as the endothelium of the prostate gland.
  • the present invention satisfies this need by providing prostate-homing pro-apoptotic peptides that combine an antimicrobial peptide with a prostate-homing peptide to produce a conjugate with selective toxicity against the prostate.
  • Related advantages are provided as well.
  • the present invention provides a chimeric prostate-homing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide portion can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence
  • the antimicrobial peptide portion can have an amphipathic ⁇ -helical structure such as the sequence (KLAKLAK) 2 (SEQ ID NO: 200), (KLAKKLA) 2 (SEQ ID NO: 201), (KAAKKAA) 2 (SEQ ID NO: 202) or (KLGKKLG) 3 (SEQ ID NO: 203).
  • the antimicrobial peptide portion contains the sequence D (KLAKLAK) 2 .
  • the present invention further provides a method of directing an antimicrobial peptide to a prostate cancer in vivo .
  • the method includes the step of administering a chimeric prostate-ho ing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence, and the antimicrobial peptide can contain a sequence such as D (KLAKLAK) 2 .
  • the chimeric prostate-ho ing pro-apoptotic peptide includes the sequence SMSIARL-GG- D (KLAKLAK) 2 .
  • Also provided by the invention is a method of inducing selective toxicity in a prostate cancer in vivo .
  • the method includes the step of administering to a subject having prostate cancer a chimeric prostate-homing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the method of inducing selective toxicity in a prostate cancer in vivo can be practiced, for example, with a prostate-homing peptide containing the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence.
  • the antimicrobial peptide can include, for example, the sequence D (KLAKLAK) 2 .
  • the chimeric prostate-homing pro-apoptotic peptide includes the sequence SMSIARL-GG- D (KLAKLAK) 2 .
  • the invention provides a method of treating a patient having prostate cancer by administering to the patient a chimeric prostate-homing pro-apoptotic peptide of the invention, whereby the chimeric peptide is selectively toxic to the tumor.
  • the chimeric peptide contains a prostate-homing peptide linked to an antimicrobial peptide, and the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide portion can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence
  • the antimicrobial peptide portion can contain, for example, the sequence
  • the chimeric peptide contains the sequence SMSIARL-GG- D (KLAKLAK) ,.
  • Figure 1 shows a computer-generated model and amino acid sequence of CNGRC-GG- D (KLAKLAK) 2 , designated "HPP-1.”
  • Upper panel CNGRC-GG- D (KLAKLAK) 2 (HPP-1) is composed of a homing domain and a membrane-disrupting domain joined by a coupling domain.
  • Lower panel Amino acid sequence of "HPP-1" corresponding to the structure shown in upper panel.
  • Figure 2 shows mitochondrial swelling and mitochondria-dependent apoptosis in the presence of D (KLAKLAK),. a. Mitochondrial swelling curve (optical absorbance spectrum) is shown in the presence of
  • Figure 3 shows mitochondrial swelling and apoptosis in dermal microvessel endothelial cells treated with CNGRC-GG- D (KLAKLAK) 2 (HPP-1).
  • b DEVD-pNA hydrolysis (caspase activation) in proliferating dermal microvessel endothelial cells treated with CNGRC-GG- D (KLAKLAK) 2 (HPP-1).
  • c Viability of proliferating dermal microvessel endothelial cells treated with HPP-1 (black bars) or control peptide D (KLAKLAK) 2 (gray bars) over time, (t test, P ⁇ 0.05).
  • FIG. 4 shows the effect of HPP-1 treatment of nude mice bearing human MDA-MB-435-derived breast carcinoma xenografts.
  • Figure 5 shows the effect of CDCRGDCFC-GG- D (KLAKLAK) 2 on oxygen-induced retinal neovascularization in newborn mice. Retinal neovessel number is shown for treatments with vehicle (black bar) ; CDCRGDCFC-GG- D (KLAKLAK) 2 (striped bar); and a control mixture of unconjugated CDCRGDCFC (SEQ ID NO: 1) and D (KLAKLAK) 2 (hatched bar) .
  • Figure 6 shows accumulation of intravenously injected biotin conjugate of prostate-homing peptide in prostate tissue.
  • a Avidin-peroxidase staining of a prostate section from a mouse injected with biotin-labeled prostate homing peptide, SMSIARL (SEQ ID NO: 207).
  • b Avidin-peroxidase staining of a prostate section from a mouse injected with biotin-labeled control peptide CARAC (SEQ ID NO: 208) .
  • Figure 7 shows apoptosis induced by SMSIARL-GG- D (KLAKLAK) 2 in the normal mouse prostate.
  • a TUNEL staining of prostate tissue from a mouse treated with SMSIARL-GG- D (KLAKLAK) 2 chimeric peptide.
  • b Larger magnification of a field similar to that in a .
  • c TUNEL staining of negative control mice treated with 250 ⁇ g of an unconjugated mixture of SMSIARL (SEQ ID NO: 207) and D (KLAKLAK) 2 .
  • Figure 8 shows survival of TRAMP mice treated with SMSIARL-GG- D (KLAKLAK) 2 , vehicle alone, D (KLAKLAK) 2 peptide alone, or SMSIARL peptide (SEQ ID NO: 207) alone.
  • Figure 9 shows binding of prostate-homing SMSIARL (SEQ ID NO: 207) phage to human prostate vasculature.
  • a and b Peroxidase staining of human prostate tissue section containing both normal and cancerous tissue overlaid with 10 9 TU SMSIARL phage (SEQ ID NO: 207) and detected with anti-phage antibody, a is an overview (x 20) while b shows a detail from panel a at a higher magnification (x 40) .
  • c Peroxidase staining as in panel a with phage lacking a peptide insert.
  • d Peroxidase staining as in a with soluble SMSIARL peptide SEQ ID NO: 207 included in the overlay.
  • Antimicrobial peptides also known as lytic peptides or channel-forming peptides, are broad spectrum anti-bacterial agents. These peptides typically disrupt bacterial cell membranes, causing cell lysis and death. Over 100 antimicrobial peptides occur naturally. In addition, analogs have been synthesized de novo as described in Javadpour et al., J. Med. Chem. 39:3107-3113 (1996) ; and Blondelle and Houghten, Biochem. 31: 12688-12694 (1992), each of which is incorporated herein by reference. While some antimicrobial peptides such as melittin are not selective and damage normal mammalian cells at the minimum bactericidal concentration, others are selective for bacterial cells. For example, the naturally occurring magainins and cecropins exhibit substantial bactericidal activity at concentrations that are not lethal to normal mammalian cells.
  • Antimicrobial peptides frequently contain cationic amino acids, which are attracted to the head groups of anionic phospholipids, leading to the preferential disruption of negatively charged membranes. Once electrostatically bound, the amphipathic helices can distort the lipid matrix, resulting in loss of membrane barrier function (Epand, The Amphipathic Helix CRC Press: Boca Raton (1993) ; Lugtenberg and van Alphen, Biochim. Biophys . Acta 737:51-115 (1983), each of which is incorporated herein by reference) . Prokaryotic cytoplasmic membranes maintain large transmembrane potentials and have a high content of anionic phospholipids.
  • the outer leaflet of eukaryotic plasma membranes generally has low, or no, membrane potential and is almost exclusively composed of zwitterionic phospholipids.
  • antimicrobial peptides can preferentially disrupt prokaryotic membranes as compared to eukaryotic membranes.
  • the present invention is directed to the surprising discovery that an antimicrobial peptide sequence can be linked to a tumor homing molecule to produce a homing pro-apoptotic conjugate that generally is non-toxic outside of eukaryotic cells but which promotes disruption of mitochondrial membranes and subsequent cell death when targeted and internalized by eukaryotic cells.
  • Homing pro-apoptotic conjugates such as HPP-1, which contains the antimicrobial peptide D (KLAKLAK) 2 linked to the cyclic tumor homing molecule CNGRC (SEQ ID NO: 8), can have selective toxicity against angiogenic endothelial cells in vivo and, thus, be useful as a new class of anti-cancer therapeutics.
  • the present invention provides a homing pro-apoptotic conjugate, which includes a tumor homing molecule that selectively homes to a selected mammalian cell type or tissue linked to an antimicrobial peptide, where the conjugate is selectively internalized by the mammalian cell type or tissue and exhibits high toxicity thereto, and where the antimicrobial peptide has low mammalian cell toxicity when not linked to the tumor homing molecule.
  • a homing pro-apoptotic conjugate of the invention can exhibit selective toxicity against angiogenic endothelial cells and can be useful, for example, in methods of inducing selective toxicity in vivo in a tumor having angiogenic vasculature.
  • a synthetic antimicrobial peptide with selective toxicity against bacteria as compared to eukaryotic cells, D (KLAKLAK) 2 induced marked mitochondrial swelling at a concentration of 10 ⁇ M
  • the antimicrobial peptide D (KLAKLAK) 2 was conjugated to the cyclic tumor homing peptide CNGRC (SEQ ID NO: 8) via a glycinylglycine bridge to produce the peptide CNGRC-GG- D (KLAKLAK) 2 , designated "HPP-1.”
  • HPP-1 was tested in a tissue culture model of angiogenesis by assaying cord formation, which is a form of migration indicated by a change in endothelial cell morphology from the usual "cobblestones" to chains or cords of cells.
  • CNGRC-GG- D (KLAKLAK) 2 or ACDCRGDCFC-GG- D (KLAKLAK) 2 displayed altered mitochondrial morphology before exhibiting the classical morphological indicators of apoptosis including nuclear condensation and fragmentation.
  • the HPP-1 peptide CNGRC-GG- D (KLAKLAK) 2 also has activity in vivo .
  • nude mice bearing human MDA-MD-435 breast carcinoma xenografts were treated with HPP-1. Tumor volume was smaller on average by one order of magnitude, and survival longer in the HPP-1 treated animal groups as compared to control groups.
  • HPP-1 treated mice outlived control mice by several months, indicating that both primary tumor growth and metastasis were inhibited. Destruction of tumor architecture and widespread cell death was evident upon histopathological analysis of the tumors, with about 50% apoptotic cell death.
  • HPP-1 also was effective against tumors derived from the human melanoma cell line C8161; and ACDCRGDCFC-GG- D (KLAKLAK) 2 was effective against MDA-MD-435 breast carcinoma tumors.
  • homing pro-apoptotic peptides based on tumor homing and antimicrobial peptide sequences can be non-toxic outside of eukaryotic cells but can promote disruption of mitochondrial membranes and subsequent cell death when internalized by the targeted eukaryotic target cells.
  • Homing pro-apoptotic peptides such as HPP-1, which have selective toxicity against angiogenic endothelial cells, can be particularly valuable as anti-cancer therapeutics.
  • retinal neovascularization can be selectively inhibited by a homing pro-apoptotic conjugate of the invention.
  • the number of retinal neovessels in mice treated with the homing pro-apoptotic conjugate is shown.
  • a homing pro-apoptotic conjugate of the invention can contain a tumor homing molecule, or can contain another homing molecule that selectively homes to a selected mammalian cell type or tissue.
  • a homing pro-apoptotic conjugate of the invention is characterized by being highly toxic to the mammalian cell type in which it is internalized.
  • the term "highly toxic” means that the conjugate is relatively effective in resulting in cell death of a selected cell type or tissue.
  • toxicity can be analyzed using one of a variety of well known assays for cell viability.
  • highly toxic is used to refer to a conjugate in which the concentration for half maximal killing (LC 50 ) is less than about 100 ⁇ M, preferably less than about 50 ⁇ M.
  • the homing pro-apoptotic conjugate HPP-1 was characterized by LC 50 s of 51, 34 and 42, respectively, for angiogenic proliferating and cord forming DMEM cells and for KS1767 cells. Moreover, the prolonged survival of tumor-bearing mice treating with a homing pro-apoptotic conjugate of the invention demonstrates that the selective toxicity can be reproduced in vivo .
  • an antimicrobial peptide means a naturally occurring or synthetic peptide having antimicrobial activity, which is the ability to kill or slow the growth of one or more microbes.
  • An antimicrobial peptide can, for example, kill or slow the growth of one or more strains of bacteria including a Gram-positive or Gram-negative bacteria, or a fungi or protozoa.
  • an antimicrobial peptide can have, for example, bacteriostatic or bacteriocidal activity against, for example, one or more strains of Escherichia coli , Pseudomonas aeruginosa or Staphylococcus aureus .
  • an antimicrobial peptide can have biological activity due to the ability to form ion channels through membrane bilayers as a consequence of self-aggregation.
  • An antimicrobial peptide is typically highly basic and can have a linear or cyclic structure. As discussed further below, an antimicrobial peptide can have an amphipathic ⁇ -helical structure (see U.S. Patent 5,789,542; Javadpour et al . , supra , 1996; Blondelle and Houghten, supra , 1992). An antimicrobial peptide also can be, for example, a ⁇ -strand/sheet-forming peptide as described in Mancheno et al . , J. Peptide Res. 51:142-148 (1998) .
  • An antimicrobial peptide can be a naturally occurring or synthetic peptide.
  • Naturally occurring antimicrobial peptides have been isolated from biological sources such as bacteria, insects, amphibians and mammals and are thought to represent inducible defense proteins that can protect the host organism from bacterial infection.
  • Naturally occurring antimicrobial peptides include the gramicidins, magainins, mellitins, defensins and cecropins (see, for example, Maloy and Kari, Biopolymers 37:105-122 (1995); Alvarez-Bravo et al., Biochem. J. 302:535-538 (1994); Bessalle et al .
  • an antimicrobial peptide also can be an analog of a natural peptide, especially one that retains or enhances amphipathicity.
  • An antimicrobial peptide incorporated within a homing pro-apoptotic conjugate of the invention has low mammalian cell toxicity when not linked to a tumor homing molecule. Mammalian cell toxicity readily can be assessed using routine assays.
  • mammalian cell toxicity can be assayed by lysis of human erythrocytes in vi tro as described in Javadpour et al., supra , 1996.
  • An antimicrobial peptide having "low mammalian cell toxicity" is not lytic to human erythrocytes or requires concentrations of greater than 100 ⁇ M for lytic activity, preferably concentrations ⁇ greater than 200, 300, 500 or 1000 ⁇ M.
  • the invention also provides a homing pro-apoptotic conjugate in which the antimicrobial peptide portion promotes disruption of mitochondrial membranes when internalized by eukaryotic cells.
  • an antimicrobial peptide preferentially disrupts mitochondrial membranes as compared to eukaryotic membranes.
  • Mitochondrial membranes like bacterial membranes but in contrast to eukaryotic plasma membranes, have a high content of negatively charged phospholipids.
  • An antimicrobial peptide can be assayed for activity in disrupting mitochondrial membranes using, for example, an assay for mitochondrial swelling (as described in Example I) or another assay well known in the art.
  • D (KLAKLAK) 2 induced marked mitochondrial swelling at a concentration of 10 ⁇ M, significantly less than the concentration required to kill eukaryotic cells.
  • the invention also provides a homing pro-apoptotic conjugate in which a tumor homing molecule is linked to an antimicrobial peptide having an amphipathic ⁇ -helical structure.
  • the antimicrobial peptide portion can have, for example, the sequence (KLAKLAK) 2 (SEQ ID NO: 200); (KLAKKLA) 2 (SEQ ID NO: 201) ; (KAAKKAA) 2 (SEQ ID NO: 202); or (KLGKKLG) 3 (SEQ ID NO: 203), in particular the sequence D (KLAKLAK) 2 .
  • a homing pro-apoptotic conjugate of the invention can have, for example, the sequence CNGRC-GG- D (KLAKLAK) 2 or ACDCRGDCFC-GG- D (KLAKLAK) 2 •
  • Antimicrobial peptides generally have random coil conformations in dilute aqueous solutions, yet high levels of helicity can be induced by helix-promoting solvents and amphipathic media such as micelles, synthetic bilayers or cell membranes.
  • ⁇ -Helical structures are well known in the art, with an ideal ⁇ -helix characterized by having 3.6 residues per turn and o o a translation of 1.5 A per residue (5.4A per turn; see Creighton, Proteins: Structures and Molecular Properties W.H Freeman, New York (1984)).
  • amphipathic ⁇ -helical structure polar and non-polar amino acid residues are aligned into an amphipathic helix, which is an ⁇ -helix in which the hydrophobic amino acid residues are predominantly on one face, with hydrophilic residues predominantly on the opposite face when the peptide is viewed along the helical axis.
  • Antimicrobial peptides of widely varying sequence have been isolated, sharing an amphipathic ⁇ -helical structure as a common feature (Saberwal et al . , Biochim. Biophvs. Acta 1197:109-131 (1994)).
  • Analogs of native peptides with amino acid substitutions predicted to enhance amphipathicity and helicity typically have increased antimicrobial activity.
  • analogs with increased antimicrobial activity also have increased cytotoxicity against mammalian cells (Maloy et al., Biopolymers 37:105-122 (1995)).
  • amphipathic ⁇ -helical structure means an ⁇ -helix with a hydrophilic face containing several polar residues at physiological pH and a hydrophobic face containing nonpolar residues.
  • a polar residue can be, for example, a lysine or arginine residue
  • a nonpolar residue can be, for example, a leucine or alanine residue.
  • An antimicrobial peptide having an amphipathic ⁇ -helical structure generally has an equivalent number of polar and nonpolar residues within the amphipathic domain and a sufficient number of basic residues to give the peptide an overall positive charge at neutral pH (Saberwal et al . , Biochim.
  • antimicrobial peptides having an amphipathic ⁇ -helical structure are well known in the art.
  • Such peptides include synthetic, minimalist peptides based on a heptad building block scheme in which repetitive heptads are composed of repetitive trimers with an additional residue.
  • Such synthetic antimicrobial peptides include, for example, peptides of the general formula [ (X ⁇ X 2 X 2 ) (X ⁇ X-) XJ n (SEQ ID NO: 205) or [ (Xj zKz ) X (X X X 2 X 2 ) ] n (SEQ ID NO: 206), where X x is a polar residue, X 2 is a nonpolar residue; and n is 2 or 3 (see Javadpour et al . , supra , 1996.
  • KLAKLAK 2 (SEQ ID NO: 200); (KLAKKLA) 2 (SEQ ID NO: 201); (KAAKKAA) 2 (SEQ ID NO: 202); and (KLGKKLG) 3 (SEQ ID NO: 203) are examples of synthetic antimicrobial peptides having an amphipathic ⁇ -helical structure. Similar synthetic, antimicrobial peptides having an amphipathic ⁇ -helical structure also are known in the art, for example, as described in U.S. Patent No. 5,789,542 to McLaughlin and Becker.
  • Helicity readily can be determined by one skilled in the art, for example, using circular dichroism spectroscopy. Percent ⁇ -helicity can be determined, for example, after measuring molar ellipticity at 222 nm as described in Javadpour et al., supra , 1996 (see, also, McLean et al., Biochemistry 30:31-37 (1991), which is incorporated by reference herein) .
  • An amphipathic ⁇ -helical antimicrobial peptide of the invention can have, for example, at least about 20% helicity when assayed in amphipathic media such as 25 mM SDS.
  • an antimicrobial peptide having an amphipathic ⁇ -helical structure can have, for example, at least about 25%, 30%, 35% or 40% helicity when assayed in 25 mM SDS.
  • An antimicrobial peptide having an ⁇ -helical structure can have, for example, from 25% to 90% helicity; 25% to 60% helicity; 25% to 50% helicity; 25% to 40% helicity; 30% to 90% helicity; 30% to 60% helicity; 30% to 50% helicity; 40% to 90% helicity or 40% to 60% helicity when in assayed in 25 mM SDS.
  • Amphipathicity can readily be determined, for example, using a helical wheel representation of the peptide (see, for example, Blondelle and Houghten, supra , 1994) .
  • the structure of an exemplary homing pro-apoptotic conjugate of the invention
  • CNGRC-GG- D (KLAKLAK) 2 is illustrated in Figure 1.
  • the homing domain, CNGRC SEQ ID NO: 8
  • D membrane disrupting domain
  • the D-amino acids in the membrane disrupting, antimicrobial portion of the conjugate can be useful in imparting increased stability upon the conjugate in vivo .
  • the membrane disrupting D (KLAKLAKKLAKLAK) portion forms an amphipathic helix.
  • the lysine residues are aligned on one face of the helix (shown as dark shaded region of helix)
  • the non-polar leucine and alanine residues are aligned on the opposite (light-shaded) face of the helix.
  • a homing pro-apoptotic conjugate of the invention can be a chimeric peptide in which the tumor homing molecule is a tumor homing peptide.
  • a homing pro-apoptotic chimeric peptide of the invention can have a variety of lengths, from about 18 amino acids to about fifty amino acids or more.
  • a chimeric peptide of the invention can have, for example, from about 20 to about fifty amino acids, preferably from 20 to 40 amino acids, more preferably from 20 to 30 amino acids.
  • Such a chimeric peptide can have, for example, an upper length of 40, 35, 30, 27, 25 or 21 amino acids.
  • a chimeric peptide of the invention can be linear or cyclic.
  • a homing pro-apoptotic chimeric peptide of the invention includes a cyclic tumor homing peptide portion.
  • a homing pro-apoptotic chimeric peptide of the invention also can be a peptidomimetic.
  • the term "peptidomimetic" is used broadly to mean a peptide-like molecule that has substantially the activity of the corresponding peptide.
  • Peptidomimetics include chemically modified peptides, peptide-like molecules containing non-naturally occurring amino acids, peptoids and the like, have the selective homing activity and the high toxicity of the peptide from which the peptidomimetic is derived (see, for example, "Burger's Medicinal Chemistry and Drug Discovery” 5th ed., vols. 1 to 3 (ed. M.E. Wolff; Wiley Interscience 1995), which is incorporated herein by reference) .
  • D amino acids can be advantageously included in the antimicrobial peptide portion of a chimeric peptide of the invention
  • Peptidomimetics provide various advantages over a peptide, including increased stability during passage through the digestive tract and, therefore, can be advantageously used as oral therapeutics.
  • a "coupling domain” can be used to link a tumor homing peptide and an antimicrobial peptide and can, for example, impart flexibility to the conjugate as a whole.
  • a coupling domain can be, for example, a glycinylglycine linker, alaninylalanine linker or other linker incorporating glycine, alanine or other amino acids. The use of a glycinylglycine coupling domain is described in Example II.
  • vasculature within a tumor generally undergoes active angiogenesis, resulting in the continual formation of new blood vessels to support the growing tumor.
  • angiogenic blood vessels are distinguishable from mature vasculature in that angiogenic vasculature expresses unique endothelial cell surface markers, including the ⁇ v ⁇ 3 integrin (Brooks, Cell 79:1157-1164 (1994); WO 95/14714, Int. Filing Date November 22, 1994) and receptors for angiogenic growth factors (Mustonen and Alitalo, J. Cell Biol. 129:895-898 (1995); Lappi, Semin. Cancer Biol. 6:279-288 (1995)).
  • tumor vasculature is histologically distinguishable from other blood vessels in that tumor vasculature is fenestrated (Folkman, Nature Med. 1:27-31 (1995); Rak et al., Anticancer Drugs 6:3-18 (1995)).
  • the unique characteristics of tumor vasculature make it a particularly attractive target for anti-cancer therapeutics .
  • tumor homing molecules can bind to the endothelial lining of small blood vessels of tumors.
  • the vasculature within tumors is distinct, presumably due to the continual neovascularization, resulting in the formation of new blood vessels required for tumor growth.
  • the distinct properties of the angiogenic neovasculature within tumors are reflected in the presence of specific markers in endothelial cells and pericytes (Folkman, Nature Biotechnol. 15:510 (1997); Risau, FASEB J. 9:926-933 (1995); Brooks et al . , supra , 1994); these markers likely are being targeted by the disclosed tumor homing molecules.
  • tumor cells depend on a vascular supply for survival and the endothelial lining of blood vessels is readily accessible to a circulating probe.
  • a therapeutic agent in order to reach solid tumor cells, a therapeutic agent must overcome potentially long diffusion distances, closely packed tumor cells, and a dense fibrous stroma with a high interstitial pressure that impedes extravasation (Burrows and Thorpe, Pharmacol. Ther. 64:155-174 (1994)).
  • tumor vasculature targeting the killing of all target cells may not be required, since partial denudation of the endothelium can lead to the formation of an occlusive thrombus halting the blood flow through the entirety of the affected tumor vessel (Burrows and Thorpe, supra , 1994) .
  • tumor vasculature targeting there is an intrinsic amplification mechanism in tumor vasculature targeting.
  • a single capillary loop can supply nutrients to up to 100 tumor cells, each of which is critically dependent on the blood supply (Denekamp, Cancer Metast. Rev. 9:267-282 (1990); Folkman, supra , 1997).
  • a tumor homing molecule that is selective for the angiogenic endothelial cells of tumor vasculature can be particularly useful for directing a pro-apoptotic antimicrobial peptide to tumor vasculature, while reducing the likelihood that the pro-apoptotic antimicrobial peptide will have a toxic effect on normal, healthy organs or tissues.
  • the invention provides a homing pro-apoptotic conjugate, which includes a tumor homing molecule that selectively homes to angiogenic endothelial cells linked to an antimicrobial peptide, where the conjugate is selectively internalized by angiogenic endothelial cells and exhibits high toxicity thereto, and where the antimicrobial peptide has low mammalian cell toxicity when not linked to the tumor homing molecule.
  • selective toxicity means enhanced cell death in a selected cell type or tissue as compared to a control cell type or tissue.
  • selective toxicity is characterized by at least a two-fold greater extent of cell death in the selected cell type or tissue, such as angiogenic endothelial cells, as compared to a control cell type or tissue, for example, angiostatic endothelial cells.
  • selective toxicity encompasses specific toxicity, whereby cell death occurs essentially only the selected cell type or tissue, as well as toxicity occurring in a limited number of cell types or tissues in addition to the selected cell type or tissue.
  • selective toxicity refers to cell death effected by all mechanisms including apoptotic and necrotic cell death.
  • a homing pro-apoptotic conjugate of the invention that exhibits selective toxicity for angiogenic endothelial cells effects enhanced cell death of the angiogenic endothelial cells as compared to angiostatic endothelial cells or surrounding cells of other types.
  • identified tumor homing molecules are useful for targeting a desired antimicrobial peptide, which is linked to the homing molecule, to a selected cell type such as angiogenic endothelial cells. After being internalized by the angiogenic endothelial cells in tumor vasculature, the antimicrobial peptide is toxic to the endothelial cells, thereby restricting the blood supply to the tumor and inhibiting tumor growth.
  • a tumor homing molecule useful in the homing pro-apoptotic conjugates of the invention can be a peptide containing, for example, an NGR motif, such as CNGRC (SEQ ID NO: 8); NGRAHA (SEQ ID NO: 6) or CNGRCVSGCAGRC (SEQ ID NO: 3) .
  • a tumor homing molecule useful in the invention also can contain an RGD motif and can be, for example, CDCRGDCFC (SEQ ID NO: 1), or can contain a GSL motif, such as the peptide CGSLVRC (SEQ ID NO: 5) .
  • Additional tumor homing molecules can be identified by screening a library of molecules by in vivo panning as set forth in further detail below (see, also, Examples IV to VIII; United States Patent No. 5,622,699, issued April 22, 1997; and Pasqualini and Ruoslahti, Nature 380:364-366 (1996), each of which is incorporated herein by reference) .
  • tumor homing molecule means an organic chemical such as a drug; a nucleic acid molecule; a peptide or peptidomimetic or protein that selectively homes in vivo to a selected cell type or tissue.
  • selective homes is meant that, in vivo, the tumor homing molecule binds preferentially to a selected cell type or tissue as compared to a control cell type, tissue or organ and generally is characterized by at least a two-fold greater localization at the selected cell type or tissue compared to a control cell type or tissue.
  • a tumor homing molecule useful in the invention can be, for example, a molecule that binds preferentially to the endothelial cells of angiogenic vasculature as compared to other cell types or angiostatic vasculature.
  • Tumor homing molecules were identified using in vivo panning as follows. By panning in vivo against a breast carcinoma, a melanoma and a Kaposi's sarcoma, phage expressing various peptides that selectively homed to tumors were identified (see Tables 2, 3 and 4, respectively) .
  • Phage peptide display libraries were constructed essentially as described in Smith and Scott ⁇ supra , 1993; see, also, Koivunen et al . , Biotechnology 13:265-270 (1995); Koivunen et al., Meth. Enzymol. 245:346-369 (1994b), each of which is incorporated herein by reference) .
  • Oligonucleotides encoding peptides having substantially random amino acid sequences were synthesized based on an "NNK" codon, wherein "N" is A, T, C or G and “K” is G or T.
  • “NNK” encodes 32 triplets, which encode the twenty amino acids and an amber STOP codon (Scott and Smith, supra , 1990) .
  • At least one codon encoding cysteine also was included in each oligonucleotide so that cyclic peptides could be formed through disulfide linkages (Example IV) .
  • the oligonucleotides were inserted in frame with the sequence encoding the gene III protein (gill) in the vector fuse 5 such that a peptide-glll fusion protein was expressed. Following expression, the fusion protein was expressed on the surface of the phage containing the vector (Koivunen et al., supra , 1994b; Smith and Scott, supra , 1993).
  • the phage isolated based on their ability to selectively home to human breast carcinoma, mouse melanoma or human Kaposi's sarcoma tumors displayed only a few different peptide sequences (see Tables 2, 3 and 4, respectively).
  • One of the screenings revealed peptide sequences that contained the arginine-glycine-aspartic acid (RGD) integrin recognition sequence (Ruoslahti, Ann. Rev. Cell Devel. Biol . 12:697 (1996)) in the context of a peptide previously demonstrated to bind selectively to ⁇ v -containing integrins (Koivunen et al., supra , 1995; WO 95/14714) .
  • RGD arginine-glycine-aspartic acid
  • NGR asparagine-glycine-arginine
  • an integrin receptor may not be the target molecule recognized by the NGR tumor homing peptides exemplified herein.
  • the term "integrin” means a heterodimeric cell surface adhesion receptor.
  • the peptides expressed by the phage that homed to the breast tumor included the peptides CGRECPRLCQSSC (SEQ ID NO: 2) and CNGRCVSGCAGRC (SEQ ID NO: 3; see Table 2; Example V).
  • tumor homing peptides including the peptides CDCRGDCFC (SEQ ID NO: 1) and CGSLVRC (SEQ ID NO: 5), were identified from two other phage libraries administered to breast tumor bearing mice (Table 2) . Some of these motifs, as well as novel ones, also were isolated by screening against mouse melanoma and human Kaposi's sarcoma (see Tables 3 and 4).
  • Homing pro-apoptotic conjugates in which the tumor homing molecule portion contains an NGR motif, RGD motif or GSL motif can be used to target a linked antimicrobial peptide to the endothelial cells of angiogenic vasculature.
  • the invention provides a homing pro-apoptotic conjugate, which includes a tumor homing peptide containing the sequence NGR linked to an antimicrobial peptide.
  • the tumor homing peptide can be, for example, CNGRC (SEQ ID NO: 8); NGRAHA (SEQ ID NO: 6) or CNGRCVSGCAGRC (SEQ ID NO: 3) .
  • the homing pro-apoptotic conjugate includes the sequence CNGRC-GG- D (KLAKLAK) 2 .
  • the invention provides a homing pro-apoptotic conjugate, which includes a tumor homing peptide containing the sequence RGD linked to an antimicrobial peptide.
  • the tumor homing peptide can be, for example, CDCRGDCFC (SEQ ID NO: 1) .
  • the homing pro-apoptotic conjugate includes the sequence ACDCRGDCFC-GG- D (KLAKLAK) 2 .
  • the invention additionally provides a homing pro-apoptotic conjugate, which includes a tumor homing peptide containing the sequence GSL linked to an antimicrobial peptide.
  • the tumor homing peptide can be, for example, CGSLVRC (SEQ ID NO: 5) .
  • one motif contained the sequence RGD (Ruoslahti, supra , 1996) embedded in the peptide structure, CDCRGDCFC (SEQ ID NO: 1), which is known to bind selectively to ⁇ v integrins (Koivunen et al., supra , 1995; WO 95/14714). Since the ⁇ v ⁇ 3 and ⁇ v ⁇ 5 integrins are markers of angiogenic vessels (Brooks et al., supra , 1994; Friedlander et al., Science 270:1500
  • a phage expressing the peptide CDCRGDCFC (SEQ ID NO: 1) was examined for tumor targeting and, as disclosed herein, homed to tumors in a highly selective manner (see Example VI) . Furthermore, homing by the CDCRGDCFC (SEQ ID NO: 1) phage was inhibited by coadministration of the free CDCRGDCFC (SEQ ID NO: 1) peptide.
  • Another breast tumor homing peptide had the sequence CNGRCVSGCAGRC (SEQ ID NO: 3), which contains the NGR motif previously shown to have weak integrin binding activity (Koivunen et al . , J. Biol. Chem. 268:20205-20210 (1993); Koivunen et al., supra , 1994a; WO 95/14714). Since an NGR containing peptide was identified, two additional peptides, the linear peptide, NGRAHA (SEQ ID NO: 6), and the cyclic peptide, CVLNGRMEC (SEQ ID NO: 7), each of which contains the NGR motif, were examined for tumor homing.
  • phage expressing NGRAHA SEQ ID NO: 6
  • CVLNGRMEC SEQ ID NO: 7
  • tumor homing was not dependent on the tumor type or on species, as the phage accumulated selectively in human breast carcinoma, as well as in the tumors of mice bearing a mouse melanoma and mice bearing a human Kaposi's sarcoma xenograft.
  • the various peptides including RGD- and NGR-containing peptides, generally were bound to the tumor blood vessels.
  • CNGRCVSGCAGRC (SEQ ID NO: 3) sequence.
  • CNGRC CNGRC (SEQ ID NO: 8) peptide was co-injected with phage expressing either CNGRCVSGCAGRC (SEQ ID NO: 3), NGRAHA (SEQ ID NO: 6) or CVLNGRMEC (SEQ ID NO: 7)
  • accumulation of the phage in the breast carcinoma xenografts was inhibited.
  • the CNGRC (SEQ ID NO: 8) peptide did not inhibit the homing of phage expressing the CDCRGDCFC (SEQ ID NO: 1) peptide, even when administered in amounts up to ten times higher than those that inhibited the homing of the NGR phage.
  • the CDCRGDCFC (SEQ ID NO: 1) peptide partially inhibited the homing of the NGR phage, although the amount needed was 5 to 10 fold higher than that of the CNGRC peptide (SEQ ID NO: 3)
  • NGR peptides and RGD peptides bind to different receptor sites in tumor vasculature .
  • GSL glycosyl-serine-leucine
  • peptides containing such motifs can be useful as tumor homing peptides and, in particular, for forming homing pro-apoptotic conjugates that can selectively deliver an antimicrobial peptide to a tumor .
  • CNGRCVSGCAGRC (SEQ ID NO: 3), was obtained as a result of in vivo panning against a breast tumor.
  • This NGR peptide which was obtained by screening a random peptide library, was a tumor homing peptide.
  • a peptide library was constructed based on the formula
  • CXXXNGRXX (SEQ ID NO: 13) or CXXCNGRCX (SEQ ID NO: 14), each of which is biased toward NGR sequences, and used for in vivo panning against a breast tumor, numerous NGR peptides were obtained (see Table 2) .
  • a tumor homing molecule of the invention can comprise the amino acid sequence RGD or NGR or GSL.
  • Such a tumor homing molecule can be a peptide as small as five amino acids, such as CNGRC (SEQ ID NO: 8) .
  • Such tumor homing peptides also can be not only at least 13 amino acids in length, which is the largest peptide exemplified herein, but can be up to 20 amino acids, or 30 amino acids, or 50 to 100 amino acids in length, as desired.
  • a tumor homing peptide of the invention conveniently is produced by chemical synthesis .
  • Immunohistochemical analysis was performed by comparing tissue staining for phage allowed to circulate for about four minutes, followed by perfusion through the heart of the mice, or with tissues analyzed 24 hours after phage injection. At 24 hours following administration, essentially no phage remain in the circulation and, therefore, perfusion is not required
  • Immunostaining also was observed following administration of phage expressing the GSL motif containing peptide, CLSGSLSC (SEQ ID NO: 4), and, like that of the NGR peptides, was localized to the blood vessels, in this case, within a melanoma tumor (see below; see, also, Examples VII and VIII) .
  • immunostaining following administration of phage expressing the RGD motif containing peptide, CDCRGDCFC (SEQ ID NO: 1) to breast tumor bearing mice was localized to the blood vessels in the tumor, but was not observed in brain, kidney or various other nontumor tissues (see Examples VI and VII; see, also, Pasqualini et al., supra , 1997).
  • mice bearing a syngeneic melanoma with phage expressing a diverse population of peptides Example VIII.
  • the B16 mouse melanoma model was selected for these studies because the tumors that form are highly vascularized and because the biology of this tumor line has been thoroughly characterized (see Miner et al., Cancer Res. 42:4631-4638 (1982)).
  • the B16 melanoma cells are of mouse origin, species differences between the host and the tumor cell donor will not affect, for example, the distribution of phage into the tumor as compared to into normal organs.
  • tumor homing peptides including, for example, the GSL moiety containing peptide CLSGSLSC (SEQ ID NO: 4; see, also, Table 3) and immunohistochemical staining of the tumor and other organs using an anti-phage antibody demonstrated that the CLSGSLSC (SEQ ID NO: 4) expressing phage resulted in immunostaining in the melanoma, but essentially no staining in skin, kidney or other control organs (Example VIII) .
  • the staining pattern generally followed the blood vessels within the melanoma, but was not strictly confined to the blood vessels.
  • tumor homing molecules such as peptides comprising an NGR, RGD or GSL motif also likely can target human vasculature.
  • the NGR phage binds to blood vessels in the transplanted human breast tumor, but not to blood vessels in normal tissues, indicating that this motif can be particularly useful for tumor targeting in patients.
  • the CDCRGDCFC SEQ ID NO: 1 peptide binds to human ⁇ v -integrins (Koivunen et al . , supra , 1995), which are selectively expressed in tumor blood vessels of human patients (Max et al., Int. J. Cancer 71:320 (1997); Max et al., Int. J.
  • CDCRGDCFC SEQ ID NO: 1
  • antimicrobial peptide can be targeted to tumor cells, themselves, because breast carcinoma cells, for example, can express the ⁇ v ⁇ 3 integrin (Pasqualini et al . , supra, 1997).
  • integrin may be involved in the progression of certain tumors such as malignant melanomas (Albelda et al., Cancer Res. 50:6757-6764 (1990); Danen et al., Int. J.
  • NGR peptides were able to deliver a therapeutically effective amount of doxorubicin to breast tumors, indicating that, even where a tumor homing molecule homes only to tumor vasculature, i.e., not directly to the tumor cells, such vasculature targeting in sufficient to confer the effect of the moiety linked to the molecule.
  • the CDCRGDCFC (SEQ ID NO: 1) phage selectively homed to each of the tumors, whereas such homing did not occur with control phage.
  • Tissue staining for the phage showed accumulation of the CDCRGDCFC (SEQ ID NO: 1) phage in the blood vessels within the tumor, whereas no staining was observed in brain, kidney or other control organs.
  • Specificity of tumor homing by the CDCRGDCFC (SEQ ID NO: 1) phage was demonstrated by competition experiments, in which coinjection of the free CDCRGDCFC (SEQ ID NO: 1) peptide greatly reduced tumor homing of the RGD phage, whereas coinjection of a non-RGD-containing control peptide had no effect on homing of the RGD phage (see Example VI) .
  • tumor homing molecules can be identified by in vivo panning and that, in some cases, a tumor homing molecule can home to vascular tissue in the tumor as well as to tumor parenchyma, probably due to the fenestrated nature of the blood vessels permitting ready exit of the phage from the circulatory system. Due to the ability of such tumor homing molecules to home to tumors, the molecules are useful for targeting a linked antimicrobial peptide to tumors.
  • the invention provides conjugates comprising a tumor homing molecule linked to a moiety, such conjugates being useful for targeting the moiety to tumor cells.
  • the ability of a molecule that homes to a particular tumor to selectively home to another tumor of the same or a similar histologic type can be determined using, for example, human tumors grown in nude mice or mouse tumors grown in syngeneic mice for these experiments.
  • human tumors grown in nude mice or mouse tumors grown in syngeneic mice for these experiments.
  • various human breast cancer cell lines including MDA-MB-435 breast carcinoma (Price et al., Cancer Res. 50:717-721 (1990)), SKBR-1-II and SK-BR-3 (Fogh et al . , J. Natl. Cancer Inst. 59:221-226 (1975)
  • mouse mammary tumor lines including EMT6 (Rosen et al., Int. J.
  • Cancer 57:706-714 (1994)) and C3-L5 are readily available and commonly used as models for human breast cancer.
  • information relating to the specificity of an identified breast tumor homing molecule for diverse breast tumors can be obtained and molecules that home to a broad range of different breast tumors or provide the most favorable specificity profiles can be identified.
  • analyses can yield new information, for example, about tumor stroma, since stromal cell gene expression, like that of endothelial cells, can be modified by the tumor in ways that cannot be reproduced in vi tro .
  • Selective homing of a molecule such as a peptide or protein to a tumor can be due to specific recognition by the peptide of a particular cell target molecule such as a cell surface receptor present on a cell in the tumor. Selectivity of homing is dependent on the particular target molecule being expressed on only one or a few different cell types, such that the molecule homes primarily to the tumor.
  • the identified tumor homing peptides at least in part, can recognize endothelial cell surface markers in the blood vessels present in the tumors.
  • most cell types, particularly cell types that are unique to an organ or tissue can express unique target molecules.
  • tumor means a mass of cells that are characterized, at least in part, by containing angiogenic vasculature.
  • the term “tumor” is used broadly to include the tumor parenchymal cells as well as the supporting stroma, including the angiogenic blood vessels that infiltrate the tumor parenchymal cell mass.
  • a tumor generally is a malignant tumor, i.e., a "cancer,” a tumor also can be nonmalignant, provided that neovascularization is associated with the tumor.
  • normal tissue tissue that is not a “tumor.”
  • a tumor homing molecule can be identified based on its ability to home a tumor, but not to a corresponding nontumor tissue.
  • the term "corresponding, " when used in reference to tumors or tissues or both, means that two or more tumors, or two or more tissues, or a tumor and a tissue are of the same histologic type.
  • the histologic type of a tissue is a function of the cells comprising the tissue.
  • a nontumor tissue corresponding to a breast tumor is normal breast tissue
  • a nontumor tissue corresponding to a melanoma is skin, which contains melanocytes.
  • a tumor homing molecule can bind specifically to a target molecule expressed by the vasculature in a tumor, which generally contains blood vessels undergoing neovascularization, in which case a tissue corresponding to the tumor would comprise nontumor tissue containing blood vessels that are not undergoing active angiogenesis.
  • a tumor homing molecule useful in the invention can be identified by screening a library of molecules by in vivo panning as disclosed herein and set forth in United States Patent No. 5,622,699, issued April 22, 1997; and Pasqualini and Ruoslahti, Nature
  • library means a collection of molecules.
  • a library can contain a few or a large number of different molecules, varying from about ten molecules to several billion molecules or more. If desired, a molecule can be linked to a tag, which can facilitate recovery or identification of the molecule.
  • the term "molecule” is used broadly to mean a polymeric or non-polymeric organic chemical such as a drug; a nucleic acid molecule such as an RNA, a cDNA or an oligonucleotide; a peptide, including a variant or modified peptide or peptide-like molecules, referred to herein as peptidomimetics, which mimic the activity of a peptide; or a protein such as an antibody or a growth factor receptor or a fragment thereof such as an Fv, Fd or Fab fragment of an antibody, which contains a binding domain.
  • the term "peptide” is used broadly herein to mean peptides, proteins, fragments of proteins and the like.
  • a molecule also can be a non-naturally occurring molecule, which does not occur in nature, but is produced as a result of in vi tro methods, or can be a naturally occurring molecule such as a protein or fragment thereof expressed from a cDNA library.
  • a tumor homing molecule also can be a peptidomimetic.
  • peptidomimetic is used broadly to mean a peptide-like molecule that has the binding activity of the tumor homing peptide.
  • peptidomimetics which include chemically modified peptides, peptide-like molecules containing non-naturally occurring amino acids, peptoids and the like, have the binding activity of a tumor homing peptide upon which the peptidomimetic is derived (see, for example, "Burger's Medicinal Chemistry and Drug Discovery," supra , 1995).
  • Methods for identifying a peptidomimetic include, for example, the screening of databases that contain libraries of potential peptidomimetics.
  • the Cambridge Structural Database contains a collection of greater than 300,000 compounds that have known crystal structures (Allen et al . , Acta Crystallogr. Section B, 35:2331 (1979)).
  • This structural depository is continually updated as new crystal structures are determined and can be screened for compounds having suitable shapes, for example, the same shape as a tumor homing molecule, as well as potential geometrical and chemical complementarity to a target molecule bound by a tumor homing peptide.
  • a structure can be generated using, for example, the program CONCORD (Rusinko et al., J. Chem. Inf. Comput . Sci. 29:251 (1989) ) .
  • CONCORD Retrieval et al.
  • Another database the Available Chemicals Directory (Molecular Design Limited, Informations Systems; San Leandro CA) , contains about 100,000 compounds that are commercially available and also can be searched to identify potential peptidomimetics of a tumor homing molecule.
  • a molecule is a peptide, protein or fragment thereof
  • the molecule can be produced in vi tro directly or can be expressed from a nucleic acid, which can be produced in vi tro .
  • Methods of synthetic peptide and nucleic acid chemistry are well known in the art.
  • a library of molecules also can be produced, for example, by constructing a cDNA expression library from mRNA collected from a cell, tissue, organ or organism of interest. Methods for producing such libraries are well known in the art (see, for example, Sambrook et al . , Molecular Cloning: A laboratory manual (Cold Spring Harbor Laboratory Press 1989), which is incorporated herein by reference) .
  • a peptide encoded by the cDNA is expressed on the surface of a cell or a virus containing the cDNA.
  • cDNA can be cloned into a phage vector such as fuse 5 (Example IV) , wherein, upon expression, the encoded peptide is expressed as a fusion protein on the surface of the phage .
  • a library of molecules can comprise a library of nucleic acid molecules, which can be DNA or RNA or an analog thereof. Nucleic acid molecules that bind, for example, to a cell surface receptor are well known (see, for example, O'Connell et al., Proc. Natl. Acad. Sci., USA 93:5883-5887 (1996); Tuerk and Gold, Science 249:505-510 (1990); Gold et al . , Ann. Rev. Biochem.
  • nucleic acid molecules can be administered to a subject having a tumor, and tumor homing molecules subsequently identified by in vivo panning.
  • the nucleic acid molecules can be nucleic acid analogs that, for example, are less susceptible to attack by nucleases (see, for example, Jelinek et al . , Biochemistry
  • in vivo panning can be used to identify a tumor homing molecule, which can be linked to an antimicrobial peptide to form a homing pro-apoptotic conjugate of the invention.
  • In vivo panning comprises administering a library to a subject, collecting a sample of a tumor and identifying a tumor homing molecule.
  • the presence of a tumor homing molecule can be identified using various methods well known in the art. Generally, the presence of a tumor homing molecule in a tumor is identified based on one or more characteristics common to the molecules present in the library, then the structure of a particular tumor homing molecule is identified.
  • a highly sensitive detection method such as mass spectrometry, either alone or in combination with a method such as gas chromatography, can be used to identify tumor homing molecules in a tumor.
  • a highly sensitive detection method such as mass spectrometry, either alone or in combination with a method such as gas chromatography, can be used to identify tumor homing molecules in a tumor.
  • a library comprises diverse molecules based generally on the structure of an organic molecule such as a drug
  • a tumor homing molecule can be identified by determining the presence of a parent peak for the particular molecule.
  • the tumor can be collected, then processed using a method such as HPLC, which can provide a fraction enriched in molecules having a defined range of molecular weights or polar or nonpolar characteristics or the like, depending, for example, on the general characteristics of the molecules comprising the library.
  • HPLC a method such as HPLC
  • Conditions for HPLC will depend on the chemistry of the particular molecule and are well known to those skilled in the art.
  • methods for bulk removal of potentially interfering cellular materials such as DNA, RNA, proteins, lipids or carbohydrates are well known in the art, as are methods for enriching a fraction containing an organic molecule using, for example, methods of selective extraction.
  • a library comprises a population of diverse organic chemical molecules, each linked to a specific oligonucleotide tag, such that the specific molecule can be identified by determining the oligonucleotide sequence using polymerase chain reaction (PCR)
  • genomic DNA can be removed from the sample of the collected tumor in order to reduce the potential for background PCR reactions.
  • a library can comprise a population of diverse molecules such as organic chemical molecules, each linked to a common, shared tag. Based on the presence and properties of the shared tag, molecules of the library that selectively home to a tumor can be substantially isolated from a sample of the tumor.
  • tumor homing molecules selectively homes to a tumor during in vivo panning such that the molecules readily can be identified.
  • various independent phage expressing the same peptide were identified in tumors formed from implanted human breast cancer cells (Table 2), from mouse melanoma cells (Table 3) or from human Kaposi's sarcoma cells (Table 4).
  • Ease of identification of a tumor homing molecule depends on various factors, including the presence of potentially contaminating background cellular material.
  • the tumor homing molecule is an untagged peptide
  • a larger number must home to the tumor in order to identify the specific peptides against the background of cellular protein.
  • an untagged organic chemical homing molecule such as a drug is identifiable because such molecules normally are absent from or present in only small numbers in the body.
  • mass spectrometry can be used to identify a tumor homing molecule.
  • the skilled artisan will recognize that the method of identifying a molecule will depend, in part, on the chemistry of the particular molecule.
  • a tumor homing molecule is a nucleic acid molecule or is tagged with a nucleic acid molecule
  • an assay such as PCR can be particularly useful for identifying the presence of the molecule because, in principle, PCR can detect the presence of a single nucleic acid molecule (see, for example, Erlich, PCR Technology: Principles and Applications for DNA Amplification (Stockton Press 1989) , which is incorporated herein by reference) .
  • Preliminary studies have demonstrated that, following intravenous injection of 10 ng of an approximately 6000 base pair plasmid into a mouse and 2 minutes in the circulation, the plasmid was detectable by PCR in a sample of lung.
  • the molecules of a library can be tagged, which can facilitate recovery or identification of the molecule.
  • tag means a physical, chemical or biological moiety such as a plastic microbead, an oligonucleotide or a bacteriophage, respectively, that is linked to a molecule of the library. Methods for tagging a molecule are well known in the art (Hermanson, Bioconjugate Techniques (Academic Press 1996) , which is incorporated herein by reference) .
  • a tag which can be a shared tag or a specific tag, can be useful for identifying the presence or structure of a tumor homing molecule of a library.
  • the term "shared tag” means a physical, chemical or biological moiety that is common to each molecule in a library.
  • Biotin for example, can be a shared tag that is linked to each molecule in a library.
  • a shared tag can be useful to identify the presence of a molecule of the library in a sample and also can be useful to substantially isolate the molecules from a sample.
  • the shared tag is biotin
  • the biotin-tagged molecules in a library can be substantially isolated by binding to streptavidin, or their presence can be identified by binding with a labeled streptavidin.
  • a library is a phage display library
  • the phage that express the peptides are another example of a shared tag, since each peptide of the library is linked to a phage.
  • a peptide such as the hemaglutinin antigen can be a shared tag that is linked to each molecule in a library, thereby allowing the use of an antibody specific for the hemaglutinin antigen to substantially isolate molecules of the library from a sample of a selected tumor.
  • a shared tag also can be a nucleic acid sequence that can be useful to identify the presence of molecules of the library in a sample or to substantially isolate molecules of a library from a sample.
  • each of the molecules of a library can be linked to the same selected nucleotide sequence, which constitutes the shared tag.
  • An affinity column containing a nucleotide sequence that is complementary to the shared tag then can be used to hybridize molecules of the library containing the shared tag, thus substantially isolating the molecules from a tumor sample.
  • a nucleotide sequence complementary to a portion of the shared nucleotide sequence tag also can be used as a PCR primer such that the presence of molecules containing the shared tag can be identified in a sample by PCR.
  • a tag also can be a specific tag.
  • the term "specific tag” means a physical, chemical or biological tag that is linked to a particular molecule in a library and is unique for that particular molecule. A specific tag is particularly useful if it is readily identifiable.
  • a nucleotide sequence that is unique for a particular molecule of a library is an example of a specific tag. For example, the method of synthesizing peptides tagged with a unique nucleotide sequence provides a library of molecules, each containing a specific tag, such that upon determining the nucleotide sequence, the identity of the peptide is known (see Brenner and Lerner, Proc. Natl. Acad.
  • nucleotide sequence as a specific tag for a peptide or other type of molecule provides a simple means to identify the presence of the molecule in a sample because an extremely sensitive method such as PCR can be used to determine the nucleotide sequence of the specific tag, thereby identifying the sequence of the molecule linked thereto.
  • nucleic acid sequence encoding a peptide expressed on a phage is another example of a specific tag, since sequencing of the specific tag identifies the amino acid sequence of the expressed peptide.
  • a shared tag or a specific tag can provide a means to identify or recover a tumor homing molecule following in vivo panning.
  • the combination of a shared tag and specific tag can be particularly useful for identifying a tumor homing molecule.
  • a library of peptides can be prepared such that each is linked to a specific nucleotide sequence tag (see, for example, Brenner and Lerner, supra, 1992), wherein each specific nucleotide sequence tag has incorporated therein a shared tag such as biotin.
  • the particular tumor homing peptides can be substantially isolated from a sample of the tumor based on the shared tag and the specific peptides can be identified, for example, by PCR of the specific tag (see Erlich, supra, 1989) .
  • a tag also can serve as a support.
  • the term "support” means a tag having a defined surface to which a molecule can be attached.
  • a tag useful as a support is a shared tag.
  • a support can be a biological tag such as a virus or virus-like particle such as a bacteriophage ("phage"); a bacterium such as E. coli ; or a eukaryotic cell such as a yeast, insect or mammalian cell; or can be a physical tag such as a liposome or a microbead, which can be composed of a plastic, agarose, gelatin or other biological or inert material.
  • phage bacteriophage
  • E. coli bacterium
  • a eukaryotic cell such as a yeast, insect or mammalian cell
  • a physical tag such as a liposome or a microbead, which can be composed of a plastic, agarose, gelatin or other biological or inert
  • a shared tag useful as a support can have linked thereto a specific tag.
  • a phage display library for example, can be considered to consist of the phage, which is a shared tag that also is a support, and the nucleic acid sequence encoding the expressed peptide, the nucleic acid sequence being a specific tag.
  • a support should have a diameter less than about 10 ⁇ m to about 50 ⁇ m in its shortest dimension, such that the support can pass relatively unhindered through the capillary beds present in the subject and not occlude circulation.
  • a support can be nontoxic, so that it does not perturb the normal expression of cell surface molecules or normal physiology of the subject, and biodegradable, particularly where the subject used for in vivo panning is not sacrificed to collect a selected tumor.
  • the tagged molecule comprises the molecule attached to the surface of the support, such that the part of the molecule suspected of being able to interact with a target molecule in a cell in the subject is positioned so as to be able to participate in the interaction.
  • the tumor homing molecule is suspected of being a ligand for a growth factor receptor
  • the binding portion of the molecule attached to a support is positioned so it can interact with the growth factor receptor on a cell in the tumor.
  • an appropriate spacer molecule can be positioned between the molecule and the support such that the ability of the potential tumor homing molecule to interact with the target molecule is not hindered.
  • a spacer molecule also can contain a reactive group, which provides a convenient and efficient means of linking a molecule to a support and, if desired, can contain a tag, which can facilitate recovery or identification of the molecule (see Hermanson, supra, 1996) .
  • a peptide suspected of being able to home to a selected tumor such as a breast carcinoma or a melanoma was expressed as the N-terminus of a fusion protein, wherein the C-terminus consisted of a phage coat protein.
  • the C-terminal coat protein linked the fusion protein to the surface of a phage such that the N-terminal peptide was in a position to interact with a target molecule in the tumor.
  • a molecule having a shared tag was formed by the linking of a peptide to a phage, wherein the phage provided a biological support, the peptide molecule was linked as a fusion protein, the phage-encoded portion of the fusion protein acted as a spacer molecule, and the nucleic acid encoding the peptide provided a specific tag allowing identification of a tumor homing peptide.
  • in vivo panning when used in reference to the identification of a tumor homing molecule, means a method of screening a library by administering the library to a subject and identifying a molecule that selectively homes to a tumor in the subject (see U.S. Patent No. 5,622,699).
  • administering to a subject when used in reference to a library of molecules or a portion of such a library, is used in its broadest sense to mean that the library is delivered to a tumor in the subject, which, generally, is a vertebrate, particularly a mammal such as a human.
  • a library can be administered to a subject, for example, by injecting the library into the circulation of the subject such that the molecules pass through the tumor; after an appropriate period of time, circulation is terminated by sacrificing the subject or by removing a sample of the tumor (Example IV; see, also, U.S. Patent No. 5,622,699; Pasqualini and Ruoslahti, supra, 1996).
  • a cannula can be inserted into a blood vessel in the subject, such that the library is administered by perfusion for an appropriate period of time, after which the library can be removed from the circulation through the cannula or the subject can be sacrificed to collect the tumor, or the tumor can be sampled, to terminate circulation.
  • a library can be shunted through one or a few organs, including the tumor, by cannulation of the appropriate blood vessels in the subject. It is recognized that a library also can be administered to an isolated perfused tumor. Such panning in an isolated perfused tumor can be useful to identify molecules that bind to the tumor and, if desired, can be used as an initial screening of a library.
  • in vivo panning to identify tumor homing molecules is exemplified herein by screening a phage peptide display library in tumor-bearing mice and identifying specific peptides that selectively homed to a breast tumor or to a melanoma tumor (Example IV) .
  • phage libraries that display protein receptor molecules including, for example, an antibody or an antigen binding fragment of an antibody such an Fv, Fd or Fab fragment; a hormone receptor such as a growth factor receptor; or a cell adhesion receptor such as an integrin or a selectin also can be used to practice the invention.
  • Variants of such molecules can be constructed using well known methods such as random mutagenesis, site-directed mutagenesis or codon based mutagenesis (see Huse, U.S. Patent No. 5,264,563, issued November 23, 1993, which is incorporated herein by reference) .
  • peptides can be chemically modified following expression of the phage but prior to administration to the subject.
  • various types of phage display libraries can be screened by in vivo panning.
  • Phage display technology provides a means for expressing a diverse population of random or selectively randomized peptides.
  • Various methods of phage display and methods for producing diverse populations of peptides are well known in the art.
  • Ladner et al. U.S. Patent No. 5,223,409, issued June 29, 1993, which is incorporated herein by reference
  • Ladner et al. describe methods for preparing diverse populations of binding domains on the surface of a phage.
  • Ladner et al . describe phage vectors useful for producing a phage display library, as well as methods for selecting potential binding domains and producing randomly or selectively mutated binding domains.
  • phage display library which can be subjected to in vivo panning in order to identify tumor homing molecules useful in the homing pro-apoptotic conjugates of the invention.
  • in vivo panning can be used to screen various other types of libraries, including, for example, an RNA or DNA library or a chemical library.
  • the tumor homing molecule can be tagged, which can facilitate recovery of the molecule from the tumor or identification of the molecule in the tumor.
  • the tag can be a moiety such as biotin, which can be linked directly to the molecule or can be linked to a support containing the molecules .
  • Biotin provides a shared tag useful for recovering the molecule from a selected tumor sample using an avidin or streptavidin affinity matrix.
  • a molecule or a support containing a molecule can be linked to a hapten such as 4-ethoxy-methylene-2-phenyl-2-oxazoline-5-one (phOx) , which can be bound by an anti-phOx antibody linked to a magnetic bead as a means to recover the molecule.
  • phOx 4-ethoxy-methylene-2-phenyl-2-oxazoline-5-one
  • In vivo panning provides a method for directly identifying tumor homing molecules that can selectively home to a tumor.
  • the term "home” or “selectively home” means that a particular molecule binds relatively specifically to a target molecule present in the tumor following administration to a subject.
  • a tumor homing molecule is characterized, in part, by exhibiting at least a two-fold (2x) greater specific binding to a tumor as compared to a control organ or tissue.
  • a molecule can localize nonspecifically to an organ or tissue containing a tumor.
  • organs such as liver and spleen, which contain a marked component of the reticuloendothelial system (RES) .
  • RES reticuloendothelial system
  • Selective homing of a tumor homing molecule can be distinguished from nonspecific binding, however, by detecting differences in the abilities of different individual phage to home to a tumor.
  • selective homing can be identified by combining a putative tumor homing molecule such as a peptide expressed on a phage with a large excess of non-infective phage or with about a five-fold excess of phage expressing unselected peptides, injecting the mixture into a subject and collecting a sample of the tumor.
  • nonspecific localization can be distinguished from selective homing by performing competition experiments using, for example, phage expressing a putative tumor homing peptide in combination with an excess amount of the "free" peptide (Example VII) .
  • a molecule that homes selectively to a tumor present in an organ containing a component of the RES can be obtained by first blocking the RES using, for example, polystyrene latex particles or dextran sulfate (see Kalin et al., Nucl. Med. Biol. 20:171-174 (1993); Ilium et al . ,
  • Nonspecific binding of phage to RES or to other sites also can be prevented by coinjecting, for example, mice with a specific phage display library together with the same phage made noninfective (Smith et al . , supra , 1990, 1993) .
  • a peptide that homes to tumor in an organ containing an RES component can be identified by preparing a phage display library using phage that exhibit low background binding to the particular organ. For example, Merrill et al. (Proc. Natl. Acad.
  • a filamentous phage variant for example, can be selected using similar methods .
  • Selective homing of a tumor homing molecule can be demonstrated by determining the specificity of a tumor homing molecule for the tumor as compared to a control organ or tissue. Selective homing also can be demonstrated by showing that molecules that home to a tumor, as identified by one round of in vivo panning, are enriched for tumor homing molecules in a subsequent round of in vivo panning. For example, phage expressing peptides that selectively home to a melanoma tumor were isolated by in vivo panning, then were subjected to additional rounds of in vivo panning. Following a second round of screening, phage recovered from the tumor showed a 3-fold enrichment in homing to the tumor as compared to brain.
  • Phage recovered from the tumor after a third round of screening showed an average of 10-fold enrichment in homing to the tumor as compared to brain.
  • Selective homing also can be demonstrated by showing that molecules that home to a selected tumor, as identified by one round of in vivo panning, are enriched for tumor homing molecules in a subsequent round of in vivo panning.
  • Tumor homing molecules can be identified by in vivo panning using, for example, a mouse containing a transplanted tumor.
  • a transplanted tumor can be, for example, a human tumor that is transplanted into immunodeficient mice such as nude mice or a murine tumor that is maintained by passage in tissue culture or in mice. Due to the conserved nature of cellular receptors and of ligands that bind a particular receptor, it is expected that angiogenic vasculature and histologically similar tumor cells in various species can share common cell surface markers useful as target molecules for a tumor homing molecule.
  • a tumor homing molecule identified using, for example, in vivo panning in a mouse having a murine tumor of a defined histological type such as a melanoma also would bind to the corresponding target molecule in a tumor in a human or other species.
  • tumors growing in experimental animals require associated neovascularization, just as that required for a tumor growing in a human or other species.
  • a tumor homing molecule that binds a target molecule present in the vasculature in a tumor grown in a mouse likely also can bind to the corresponding target molecule in the vasculature of a tumor in a human or other mammalian subject.
  • a tumor homing molecule identified for example, by homing to a human breast tumor, also to home to a human Kaposi's sarcoma or to a mouse melanoma indicates that the target molecules are shared by many tumors. Indeed, the results disclosed herein demonstrate that the target molecules are expressed in the neovasculature, which is host tissue (see Example VII) .
  • a tumor homing molecule identified using in vivo panning in an experimental animal such as a mouse readily can be examined for the ability to bind to a corresponding tumor in a human patient by demonstrating, for example, that the molecule also can bind specifically to a sample of the tumor obtained from the patient.
  • the CDCRGDCFC SEQ ID NO: 1
  • phage and NGR peptides have been shown to bind to blood vessels in microscopic sections of human tumors, whereas little or no binding occurs in the blood vessels of nontumor tissues.
  • routine methods can be used to confirm that a tumor homing molecule identified using in vivo panning in an experimental animal also can bind the target molecule in a human tumor.
  • the steps of administering the library to the subject, collecting a selected tumor and identifying tumor homing molecules that home to the tumor comprise a single round of in vivo panning.
  • one or more additional rounds of in vivo panning generally are performed.
  • the molecules recovered from the tumor in the previous round are administered to a subject, which can be the same subject used in the previous round, where only a part of the tumor was collected.
  • the relative binding selectivity of the molecules recovered from the first round can be determined by administering the identified molecules to a subject, collecting the tumor, and determining whether more phage are recovered from the tumor following the second round of screening as compared to those recovered following the first round.
  • a control organ or tissue also can be collected and the molecules recovered from the tumor can be compared with those recovered from the control organ.
  • no molecules are recovered from a control organ or tissue following a second or subsequent round of in vivo panning.
  • a proportion of the molecules also will be present in a control organ or tissue. In this case, the ratio of molecules in the selected tumor as compared to the control organ (selected: control) can be determined.
  • phage that homed to melanoma following a first round of in vivo panning demonstrated a 3x enrichment in homing to the selected tumor as compared to the control organ, brain, following two additional rounds of panning (Example VIII) .
  • Additional rounds of in vivo panning can be used to determine whether a particular molecule homes only to the selected tumor or can recognize a target on the tumor that also is expressed in one or more normal organs or tissues in a subject or is sufficiently similar to the target molecule on the tumor. It is unlikely that a tumor homing molecule also will home to a corresponding normal tissue because the method of in vivo panning selects only those molecules that home to the selected tumor. Where a tumor homing molecule also directs homing to one or more normal organs or tissues in addition to the tumor, the organs or tissues are considered to constitute a family of selected organs or tissues. Using the method of in vivo panning, molecules that home to only the selected tumor can be distinguished from molecules that also home to one or more selected organs or tissues. Such identification is expedited by collecting various organs or tissues during subsequent rounds of in vivo panning.
  • control organ or tissue is used to mean an organ or tissue other than the tumor for which the identification of a tumor homing molecule is desired.
  • a control organ or tissue is characterized in that a tumor homing molecule does not selectively home to the control organ.
  • a control organ or tissue can be collected, for example, to identify nonspecific binding of the molecule or to determine the selectivity of homing of the molecule.
  • nonspecific binding can be identified by administering, for example, a control molecule, which is known not to home to a tumor but is chemically similar to a potential tumor homing molecule.
  • administration of the supports alone, also can be used to identify nonspecific binding.
  • a phage that expresses the gene III protein, alone, but that does not contain a peptide fusion protein can be studied by in vivo panning to determine the level of nonspecific binding of the phage support.
  • specific homing of a tumor homing molecule readily can be identified by examining the selected tumor tissue as compared to a corresponding nontumor tissue, as well as to control organs or tissues.
  • immunohistological analysis can be performed on a tumor tissue and corresponding nontumor tissue using an antibody specific for a phage used to display tumor homing peptides (see Example VII).
  • an antibody can be used that is specific for a shared tag that is expressed with the peptide, for example, a FLAG epitope or the like, such detection systems being commercially available.
  • a library of molecules which contains a diverse population of random or selectively randomized molecules of interest, is prepared, then administered to a subject. At a selected time after administration, the subject is sacrificed and the tumor is collected such that the molecules present in the tumor can be identified (see Example IV) . If desired, one or more control organs or tissues or a part of a control organ or tissue can be sampled.
  • mice bearing a breast tumor or a melanoma tumor were injected with a phage peptide display library, then, after about 1 to 5 minutes, the mice were anesthetized, either frozen in liquid nitrogen or, preferably, are perfused through the heart to terminate circulation of the phage, the tumor and one or more control organs were collected from each, phage present in the tumor and the control organs were recovered and peptides that selectively homed to the respective tumors were identified (see Examples IV, V and VIII) .
  • the animals were sacrificed to collect the selected tumor and control organ or tissue. It should be recognized, however, that only a part of a tumor need be collected to recover a support containing a tumor homing molecule and, similarly, only part of an organ or tissue need be collected as a control.
  • a part of a tumor for example, can be collected by biopsy, such that a molecule such as a peptide expressed by a phage can be administered to the same subject a second time or more, as desired.
  • the tag or support should be nontoxic and biodegradable, so as not to interfere with subsequent rounds of screening.
  • vi tro studies provide no insight as to whether a peptide that can specifically bind to a selected receptor in vi tro also will bind the receptor in vivo or whether the binding peptide or the receptor are unique to a specific organ in the body.
  • the in vitro methods are performed using defined, well-characterized target molecules in an artificial system. For example, Goodson et al., supra , 1994, utilized cells expressing a recombinant urokinase receptor.
  • vi tro methods are limited in that they require prior knowledge of the target molecule and yield little if any information regarding in vivo utility.
  • vi tro panning against cells in culture also has been used to identify molecules that can specifically bind to a receptor expressed by the cells (Barry et al . , Nature Med. 2:299-305 (1996), which is incorporated herein by reference) .
  • the cell surface molecules that are expressed by a cell in vivo often change when the cell is grown in culture.
  • vi tro panning methods using cells in culture also are limited in that there is no guarantee a molecule that is identified due to its binding to a cell in culture will have the same binding ability in vivo .
  • in vivo panning requires no prior knowledge or availability of a target molecule and identifies molecules that bind to cell surface target molecules that are expressed in vivo . Also, since the "nontargeted" tissues are present during the screening, the probability of isolating tumor homing molecules that lack specificity of homing is greatly reduced. Furthermore, in obtaining tumor homing molecules by in vivo panning, any molecules that may be particularly susceptible to degradation in the circulation in vivo due, for example, to a metabolic activity, are not recovered. Thus, in vivo panning provides significant advantages over previous methods by identifying tumor homing molecules that selectively home in vivo to a target molecule present in a tumor.
  • a molecule such as a peptide expressed on a phage recognizes and binds to a target molecule present on endothelial cells lining the blood vessels in a tumor.
  • Evidence indicates, for example, that the vascular tissues in various organs differ from one another and that such differences can be involved in regulating cellular trafficking in the body.
  • lymphocytes home to lymph nodes or other lymphoid tissues due, in part, to the expression of specific "address" molecules by the endothelial cells in those tissues (Salmi et al., Proc. Natl. Acad.
  • endothelial cell markers provide a potential target that can be selectively bound by a tumor homing molecule and used to direct a linked antimicrobial peptide to a tumor.
  • Additional components can be included as part of the homing pro-apoptotic conjugate, if desired.
  • spacers are well known in the art, as described, for example, in Fitzpatrick and Garnett, Anticancer Drug Des. 10:1-9 (1995)).
  • a homing pro-apoptotic chimeric peptide of the invention can readily be synthesized in required quantities using routine methods of solid state peptide synthesis.
  • a chimeric peptide of the invention also can be purchased from a commercial source (for example, AnaSpec, Inc.; San Jose, CA) .
  • the antimicrobial peptide portion can be synthesized independently using well known methods or obtained from commercial sources.
  • an antimicrobial peptide to a tumor homing molecule
  • methods of linking haptens to carrier proteins as used routinely in the field of applied immunology (see, for example, Harlow and Lane, supra , 1988; Hermanson, supra , 1996).
  • a premade antimicrobial peptide also can be conjugated to a tumor homing peptide using, for example, carbodiimide conjugation (Bauminger and Wilchek, Meth. Enzymol . 70:151-159 (1980), which is incorporated herein by reference) .
  • the preparative procedure is simple, relatively fast, and is carried out under mild conditions.
  • Carbodiimide compounds attack carboxylic groups to change them into reactive sites for free amino groups.
  • Carbodiimide conjugation has been used to conjugate a variety of compounds to carriers for the production of antibodies.
  • the water soluble carbodiimide, l-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) can be useful for conjugating an antimicrobial peptide to a tumor homing molecule.
  • EDC water soluble carbodiimide, l-ethyl-3- (3-dimethylaminopropyl) carbodiimide
  • Such conjugation requires the presence of an amino group, which can be provided, for example, by an antimicrobial peptide, and a carboxyl group, which can be provided by the tumor homing molecule.
  • EDC also can be used to prepare active esters such as N-hydroxysuccinimide (NHS) ester.
  • NHS N-hydroxysuccinimide
  • the NHS ester which binds only to amino groups, then can be used to induce the formation of an amide bond with the single amino group of the doxorubicin.
  • EDC and NHS in combination is commonly used for conjugation in order to increase yield of conjugate formation (Bauminger and Wilchek, supra , 1980) .
  • Other methods for conjugating an antimicrobial peptide to a tumor homing molecule also can be used.
  • sodium periodate oxidation followed by reductive alkylation of appropriate reactants can be used, as can glutaraldehyde crosslinking.
  • glutaraldehyde crosslinking it is recognized that, regardless of which method of producing a conjugate of the invention is selected, a determination must be made that the tumor homing molecule maintains its targeting ability and that the antimicrobial peptide maintains its antimicrobial activity. Methods known in the art can confirm the activity of a homing pro-apoptotic conjugate of the invention.
  • the yield of antimicrobial peptide/tumor homing molecule conjugate formed is determined using routine methods. For example, HPLC or capillary electrophoresis or other qualitative or quantitative method can be used (see, for example, Liu et al . , J. Chromatogr. 735:357-366 (1996); Rose et al., J. Chromatogr. 425:419-412 (1988), each of which is incorporated herein by reference; see, also, Example VIII) .
  • the skilled artisan will recognize that the choice of a method for determining yield of a conjugation reaction depends, in part, on the physical and chemical characteristics of the specific antimicrobial peptide and tumor homing molecule. Following conjugation, the reaction products are desalted to remove any free peptide or molecule.
  • the present invention also provides methods of directing an antimicrobial peptide in vivo to a tumor having angiogenic vasculature.
  • the method is practiced by administering a homing pro-apoptotic conjugate of the invention to a subject containing a tumor having angiogenic vasculature.
  • the antimicrobial peptide can include, for example, the sequence D (KLAKLAK) 2 .
  • Particularly useful conjugates that can be administered to a subject containing a tumor having angiogenic vasculature include CNGRC-GG- D (KLAKLAK) 2 and ACDCRGDCFC-GG- D (KLAKLAK) 2 .
  • the present invention additionally provides methods of inducing selective toxicity in vivo in a tumor having angiogenic vasculature.
  • the methods are practiced by administering a homing pro-apoptotic conjugate of the invention to a subject containing a tumor having angiogenic vasculature.
  • An antimicrobial peptide useful in inducing selective toxicity in a method of the invention can be, for example, a peptide containing the sequence D (KLAKLAK) 2 .
  • Particularly useful conjugates that can be administered to induce selective toxicity in vivo in a tumor having angiogenic vasculature include CNGRC-GG- D (KLAKLAK) 2 and ACDCRGDCFC-GG- D (KLAKLAK) 2 .
  • a homing pro-apoptotic conjugate of the invention is administered to the patient and is selectively toxic to the tumor.
  • the antimicrobial peptide portion can include, for example, the sequence D (KLAKLAK) 2 .
  • the homing pro-apoptotic conjugate has the sequence CNGRC-GG- D (KLAKLAK) 2 or ACDCRGDCFC-GG- D (KLAKLAK) 2 .
  • a homing pro-apoptotic conjugate of the invention can be administered as a pharmaceutical composition containing, for example, the conjugate and a pharmaceutically acceptable carrier.
  • pharmaceutically acceptable carriers include, for example, aqueous solutions such as water or physiologically buffered saline or other solvents or vehicles such as glycols, glycerol, oils such as olive oil or injectable organic esters.
  • a pharmaceutically acceptable carrier can contain physiologically acceptable compounds that act, for example, to stabilize or to increase the absorption of the conjugate.
  • physiologically acceptable compounds include, for example, carbohydrates, such as glucose, sucrose or dextrans; antioxidants, such as ascorbic acid or glutathione; chelating agents; low molecular weight proteins; or other stabilizers or excipients.
  • carbohydrates such as glucose, sucrose or dextrans
  • antioxidants such as ascorbic acid or glutathione
  • chelating agents such as ascorbic acid or glutathione
  • low molecular weight proteins or other stabilizers or excipients.
  • the pharmaceutical composition also can contain an agent such as a cancer therapeutic agent.
  • a homing pro-apoptotic conjugate of the invention can be administered as a pharmaceutical composition to a subject by various routes including, for example, orally or parenterally, such as intravenously.
  • a pharmaceutical composition containing the conjugate can be administered by injection or by intubation.
  • the pharmaceutical composition also can be a tumor homing molecule linked to liposomes or other polymer matrices, which can have incorporated therein, an antimicrobial peptide (Gregoriadis, Liposome Technology, Vol. 1 (CRC Press, Boca Raton, FL 1984), which is incorporated herein by reference) .
  • Liposomes for example, which consist of phospholipids or other lipids, are nontoxic, physiologically acceptable and metabolizable carriers that are relatively simple to make and administer.
  • an effective amount of the homing pro-apoptotic conjugate must be administered to the subject.
  • the term "effective amount” means the amount of the conjugate that produces the desired effect. An effective amount often will depend on the particular antimicrobial peptide linked to the tumor homing molecule.
  • An effective amount of a homing pro-apoptotic conjugate in which a tumor homing molecule is linked to a particular antimicrobial peptide can be determined using methods well known to those in the art.
  • a homing pro-apoptotic conjugate will depend, in part, on the chemical structure of the molecule. Peptides, for example, are not particularly useful when administered orally because they can be degraded in the digestive tract. However, methods for chemically modifying peptides to render them less susceptible to degradation by endogenous proteases or more absorbable through the alimentary tract, including incorporation of D-amino acids, are well known (see, for example, Blondelle et al., supra , 1995; Ecker and Crooke, supra , 1995; Goodman and Ro, supra , 1995) . Such modifications can be performed on tumor homing peptides identified by in vivo panning as well as on antimicrobial peptides .
  • libraries of peptidomimetics which can contain D-amino acids, other non-naturally occurring amino acids, or chemically modified amino acids; or can be organic molecules that mimic the structure of a peptide; or can be peptoids such as vinylogous peptoids, are known in the art and can be used to identify tumor homing molecules that are stable for oral administration.
  • a tumor homing peptide can have a linear or cyclic structure. Cysteine residues were included in some peptides, allowing cyclization of the peptides. In particular, peptides containing at least two cysteine residues cyclize spontaneously. In addition, such cyclic peptides also can be active when present in a linear form (see, for example, Koivunen et al., supra , 1993). For example, the linear peptide, NGRAHA (SEQ ID NO: 6), also was useful as tumor homing molecule (see Table 2) .
  • one or more cysteine residues in the tumor homing peptides disclosed herein or otherwise identified as tumor homing peptides can be deleted without significantly affecting the tumor homing activity of the peptide.
  • Methods for determining the necessity of a cysteine residue or of amino acid residues N-terminal or C-terminal to a cysteine residue for tumor homing activity of a peptide of the invention are routine and well known in the art.
  • tumor homing molecules also can home to angiogenic vasculature that is not contained within a tumor.
  • tumor homing molecules containing either the RGD motif or the GSL motif specifically homed to retinal neovasculature Smith et al., Invest. Ophthamol. Vis. Sci. 35:101-111 (1994), which is incorporated herein by reference
  • tumor homing peptides containing the NGR motif did not accumulate substantially in this angiogenic vasculature.
  • Methods as disclosed herein can be used to distinguish tumor homing peptides from peptides that home to nontumor angiogenic vasculature.
  • One skilled in the art understands that, preferably, for treatment of a tumor, one administers a conjugate having a tumor homing peptide, which selectively homes to tumor vasculature.
  • the invention provides chimeric prostate-homing pro-apoptotic peptides which can be used to treat, for example, benign prostate hyperplasia or cancer of the prostate.
  • SMSIARL peptide SEQ ID NO: 207
  • the prostate homing peptide SMSIARL SEQ ID NO: 207) can be used to selectively deliver a linked moiety, such as biotin or phage, to prostate tissue.
  • SMSIARL-GG- D KLAKLAK 2 chimeric peptide
  • no evidence of apoptosis was observed in non-prostate tissues (see Figure 7 and Example IX. C).
  • the results disclosed herein also demdnstrate that administration of SMSIARL-GG- D (KLAKLAK) 2 chimeric peptide can extend the survival of TRAMP mice, which develop prostate cancer under the influence of a transgene as described in Gingrich et al., Cancer Res . 56: 4096-4102 (1996) .
  • Figure 8 shows that
  • SMSIARL-GG- D (KLAKLAK) 2 -treated mice survived longer than mice treated with vehicle alone, D (KLAKLAK) 2 peptide alone, or SMSIARL peptide (SEQ ID NO: 207) alone. Based on these results, the invention provides a chimeric prostate-ho ing pro-apoptotic peptide as well as methods of using the peptide to treat a patient having prostate cancer as described further below.
  • the present invention provides a chimeric prostate-homing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide portion can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence
  • the antimicrobial peptide portion can have an amphipathic ⁇ -helical structure such as the sequence (KLAKLAK) 2 (SEQ ID NO: 200), (KLAKKLA) 2 (SEQ ID NO: 201), (KAAKKAA), (SEQ ID NO: 202) or (KLGKKLG) 3 (SEQ ID NO: 203).
  • the antimicrobial peptide portion contains the sequence D (KLAKLAK) 2 .
  • An exemplary prostate-homing pro-apoptotic peptide is provided herein as SMSIARL-GG- D (KLAKLAK) 2 .
  • the present invention further provides a method of directing an antimicrobial peptide in vivo to a prostate cancer.
  • the method includes the step of administering a chimeric prostate-homing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence, and the antimicrobial peptide can contain a sequence such as D (KLAKLAK) 2 .
  • the chimeric prostate-homing pro-apoptotic peptide includes the sequence SMSIARL-GG- D (KLAKLAK) 2 .
  • Also provided by the invention is a method of inducing selective toxicity in vivo in a prostate cancer.
  • the method includes the step of administering to a subject containing a prostate cancer a chimeric prostate-homing pro-apoptotic peptide that contains a prostate-homing peptide linked to an antimicrobial peptide, where the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the method of inducing selective toxicity in vivo in a prostate cancer can be practiced, for example, with a prostate-homing peptide containing the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence.
  • the antimicrobial peptide can include, for example, the sequence D (KLAKLAK) 2 -
  • the chimeric prostate-homing pro-apoptotic peptide includes the sequence SMSIARL-GG- D (KLAKLAK) 2 .
  • the invention provides a method of treating a patient having prostate cancer by administering to the patient a chimeric prostate-homing pro-apoptotic peptide of the invention, whereby the chimeric peptide is selectively toxic to the tumor.
  • the chimeric peptide contains a prostate-homing peptide linked to an antimicrobial peptide, and the chimeric peptide is selectively internalized by prostate tissue and exhibits high toxicity thereto, while the antimicrobial peptide has low mammalian cell toxicity when not linked to the prostate-homing peptide.
  • the prostate-homing peptide portion can contain, for example, the sequence SMSIARL (SEQ ID NO: 207) or a functionally equivalent sequence, and the antimicrobial peptide portion can contain, for example, the sequence D (KLAKLAK) 2 .
  • the chimeric peptide contains the sequence SMSIARL-GG- D (KLAKLAK) 2 .
  • prostate-homing peptide means a peptide that selectively homes in vivo to prostate tissue as compared to control tissue, such as brain. Such a peptide generally is characterized by at least a two-fold greater localization to prostatic tissue as compared to a control cell type or tissue.
  • a prostate homing peptide can selectively home, for example, to prostate vasculature as compared to other cell types or , other vasculature (see Example IX) .
  • a chimeric peptide of the invention is selectively delivered to the prostate due to the selective homing activity of the prostate-homing peptide portion.
  • a variety of prostate-homing peptides are useful in the invention, including SMSIARL (SEQ ID NO: 207) and VSFLEYR (SEQ ID NO: 222), which were identified by injection of an X 7 library into mice (Table 7) and subsequent in vivo panning as described in U.S. Patent No. 5,622,699.
  • the prostate homing peptides SMSIARL (SEQ ID NO: 21) and VSFLEYR (SEQ ID NO: 22) exhibited a 34-fold and 17-fold enrichment, respectively, in prostate as compared to brain.
  • the invention relies on a prostate-homing peptide which contains the sequence SMSIARL (SEQ ID NO: 207), or a functionally equivalent sequence.
  • sequence SMSIARL SEQ ID NO: 207
  • functionally equivalent sequence means a sequence that binds selectively to the endothelium of prostatic blood vessels, as shown in Figure 9 for the sequence SMSIARL (SEQ ID NO: 207), and that functions similarly in that the sequence binds selectively to the same receptor.
  • the chimeric prostate-homing pro-apoptotic peptides of the invention can be used to induce selective toxicity in a variety of prostatic disorders.
  • Such disorders include benign nodular hyperplasia of the prostate as well as primary or secondary cancers including clinically apparent as well as subclinical cancers.
  • Cancers to be treated with a chimeric peptide of the invention include prostatic carcinomas such as adenocarcinomas .
  • the synthetic 14-mer KLAKLAKKLAKLAK (SEQ ID NO: 200), designated (KLAKLAK) 2 , was selected because it kills bacteria at a concentration two orders of magnitude lower than the concentration required to kill eukaryotic cells (Javadpour et al . , J. Med. Chem. 39:3107-3113 (1996)).
  • the all D-enantiomer, D (KLAKLAK) 2 was used to avoid degradation by proteases (Bessalle et al., FEBS Lett. 274:151-155 (1990); Wade et al., Proc. Natl. Acad. Sci. 87:4761-4765 (1990)).
  • P ( ' KLAKLAK ) joreferentiallv disrupts mi tochondrial membranes
  • D (KLAKLAK) 2 The ability of D (KLAKLAK) 2 to disrupt mitochondrial membranes preferentially over eukaryotic plasma membranes was evaluated by mitochondrial swelling assays and in a mitochondria-dependent cell-free system of apoptosis, and by cytotoxicity assays.
  • Mitochondrial swelling assays were performed as follows. Briefly, rat liver mitochondria were prepared as described in Ellerby et al., J. Neurosci. 17:6165-6178 (1997) . Peptides were synthesized at higher than 90% purity by HPLC ( DLSLARLATARLAI (SEQ ID NO: 204), Coast Scientific, Inc., San Diego, CA; all other peptides, AnaSpec, Inc.). Mitochondria were treated with a concentration of 10 ⁇ M D (KLAKLAK) 2 , 10 ⁇ M DLSLARLATARLAI negative control peptide (SEQ ID NO: 204), or 200 ⁇ M Ca +2 as a positive control. Peptides were added to mitochondria in a cuvette, and swelling was quantified by measuring the optical absorbance at 520 nm.
  • D (KLAKLAK) 2 induced marked mitochondrial swelling. Mild swelling was evident at a concentration of 3 ⁇ M, two orders of magnitude less than the concentration required to kill eukaryotic cells (approximately 300 ⁇ M) , as measured by the lethal concentration required to kill 50% of a cell monolayer (LC 50 ; Table 1) .
  • the non- ⁇ -helix forming peptide DLSLARLATARLAI (SEQ ID NO: 204) used as a negative control did not induce mitochondrial swelling.
  • the D (KLAKLAK) , peptide was assayed for the ability to activate mitochondria-dependent apoptosis in a cell-free system composed of normal mitochondria suspended in normal cytosolic extract (Ellerby et al., J. Neurosci. 17:6165-6178 (1997)). Apoptosis was measured by characteristic caspase-3 processing from an inactive proform to the active protease (Alnemri et al . , Cell 87:171 (1996)).
  • the cell-free apoptosis assays were performed essentially as follows.
  • the cell-free systems were reconstituted as described in Ellerby et al., supra , 1997, and, for mitochondria-dependent reactions, rat liver mitochondria were suspended in normal (non-apoptotic) cytosolic extract prepared from dermal microvessel endothelial cells. After adding peptides at a concentration of 100 ⁇ M and incubating for 2 hours at 30°C or 37°C, mitochondria were removed by centrifugation, and the supernatant analyzed by SDS/PAGE immunoblotting on a 12% gel (Biorad; Hercules, CA) . Proteins were transferred to PVDF membranes (Biorad) and incubated with anti-caspase-3 antibody (Santa Cruz Biotechnology; Santa Cruz, CA) , followed by ECL detection (Amersham; Arlington Heights, IL) .
  • Characteristic caspase-3 processing was measured in dermal microvessel endothelial cell lysates as described in Ellerby et al., supra , 1997. Briefly, aliquots of cell lysates (1 ⁇ l lysate, 8-15 mg/ml) were added to 100 ⁇ M N-acetyl-Asp-Glu-Val-Asp-pNA (DEVD-pNA; BioMol; 100 ⁇ l, 100 mM HEPES, 10% sucrose, 0.1% CHAPS, 1 mM DTT, pH 7.0). Hydrolysis of DEVD-pNA was monitored spectrophotometrically (400 nm) at 25°C.
  • CNGRC-GG- D (KLAKLAK) 2 (HPP-1) inhibits angiogenesis in a tissue culture model.
  • Chimeras were prepared containing a homing domain linked through a glycinylglycine bridge to an antimicrobial peptide.
  • peptides were synthesized commercially to higher than 90% purity by HPLC by AnaSpec, Inc.
  • the homing domain was either the cyclic (disulfide bond between cysteines) CNGRC peptide (SEQ ID NO: 8; see Figure 1), or the double cyclic ACDCRGDCFC peptide (SEQ ID NO: 16) , both of which have tumor-homing properties (Pasqualini et al . , Nature Biotech. 15:542-546 (1997); Arap et al . , Science 279:377-380 (1998)) and can be internalized (Arap et al . , supra , 1998; Hart et al . , J. Biol. Chem. 269:12468-12474 (1994); Bretscher et al., EMBO . J.
  • the homing domain was synthesized from all L amino acids.
  • the glycinylglycine bridge was used to couple the homing and antimicrobial domains to impart peptide flexibility and minimize potential steric interactions.
  • HPP-1 was assayed on normal human dermal microvessel endothelial cells (DMECs) under the angiogenic conditions of proliferation and cord formation.
  • DMECs normal human dermal microvessel endothelial cells
  • HPP-1 was assayed under the angiostatic condition of a monolayer maintained at 100% confluency (as described below) .
  • DMECs dermal microvessel endothelial cells
  • CADMEC Growth MediaTM Cell Applications, Inc. ; San Diego, CA
  • Dermal microvessel endothelial cells were then cultured under three experimental conditions: proliferation, 30% confluency in a growth media supplemented with 500 ng/ml human recombinant vascular endothelial growth factor (VEGF; Pharmingen) ; no proliferation, 100% confluency in media formulated to maintain a monolayer; and cord formation, 60% confluency (required for induction) in media formulated to induce cord formation.
  • VEGF vascular endothelial growth factor
  • the KS1767 and MDA-MB-435 cells were cultured as described in Arap et al., supra , 1998; Hernier et al . , supra , 1994).
  • Percent viability and LC 50 were determined by apoptotic morphology as described in Ellerby et al., J. Neurosci. 17:6165-6178 (1997).
  • percent viability assays dermal microvessel endothelial cells were treated with 60 ⁇ M HPP-1 or control peptide D (KLAKLAK) 2 .
  • cell culture medium was aspirated from adherent cells, and the cells were gently washed once with PBS at 37°C.
  • LC 50 for the untargeted control D (KLAKLAK) 2 under angiogenic conditions was similar to the LC 50 for HPP-1 under angiostatic conditions.
  • a mixture of uncoupled D (KLAKLAK) 2 and CNGRC (SEQ ID NO: 8), a non-targeted form CARAC-GG- D (KLAKLAK) 2 , and a scrambled form CGRNC-GG- D (KLAKLAK) 2 gave results similar to D (KLAKLAK) 2 .
  • ACDCRGDCFC-GG- D (KLAKLAK) 2 gave results similar to those • for CNGRC-GG- D (KLAKLAK) 2 (HPP-1; data not shown).
  • Mi tochondrial morphology of dermal microvessel endothelial cells trea ted with HPP-1
  • Mitochondrial morphology of dermal microvessel endothelial cells was assessed in proliferating cells after treatment with 60 ⁇ M HPP-1,
  • ACDCRGDCFC-GG- D KLAKLAK 2 or untargeted D (KLAKLAK) 2 as follows.
  • Dermal microvessel endothelial cells were stained after 24 and 72 hours treatment with peptide by incubation for 30 min at 37°C with 100 nM mitochondrial stain MitoTracker RedTM (Molecular Probes, Inc., Eugene , OR) and 500 nM of the nuclear stain DAPI (Molecular Probes, Inc.).
  • Mitochondria were subsequently visualized using fluorescence microscopy (lOOx) under an inverted microscope using a triple wavelength filter set (Nikon) .
  • the mitochondria of dermal microvessel endothelial cells treated for 24 hours with D (KLAKLAK), remained morphologically normal, while those treated with each prototype exhibited altered mitochondrial morphology.
  • altered mitochondrial morphology was evident in approximately 80% of cells treated with CNGRC-GG- D (KLAKLAK) 2 or
  • ACDCRGDCFC-GG- D (KLAKLAK) 2 before the cells rounded-up.
  • the CNGRC-GG- D (KLAKLAK) 2 (HPP-1) treated dermal microvessel endothelial cells exhibited the classic morphological indicators of apoptosis, including nuclear condensation and fragmentation, as seen at 72 hours (Ellerby et al., supra , 1997). Apoptotic cell death was confirmed with by assaying for caspase activity (see Figure 3b; Ellerby et al., supra , 1997). Viabili ty of KS1 767 and MDA-MB-435 cells trea ted wi th HPP-1
  • HPP-1 was as toxic to KS1767 cells, which are derived from Kaposi's sarcoma, as to the proliferating or migrating dermal microvessel endothelial cells (Table 1; Hernier et al., AIDS 8: 575-581 (1994)). In contrast, HPP-1 was less toxic to MDA-MB-435 human breast carcinoma cells by approximately one order of magnitude (Table 1) .
  • KS1767 cells which are of endothelial origin, resemble angiogenic endothelial cells and bind the CNGRC peptide (SEQ ID NO: 8), whereas MDA-MB-435 cells do not (Samaniego et al., Amer. J. Path. 152:1433-1443 (1998); Arap et al . , supra , 1998) .
  • CNGRC-GG- D KLAKLAK 2 (HPP-1) inhibits tumor growth and prolongs survival of tumor bearing animals.
  • This example further demonstrates that CDCRGDCFC-GG- D (KLAKLAK) 2 inhibits retinal neovascularization.
  • mice bearing human MDA-MD-435 breast carcinoma xenografts were established in 2 month-old female nude mice (Jackson Labs; Bar Harbor, ME) as described in Arap et al., supra , 1998. After mice were anesthetized with a mixture of 2, 2, 2-tribromoethanol (Aldrich; Milwaukee, WI) and 2-methyl-butanol (Aldrich) prepared in distilled water, peptides were administered intravenously through the tail vein at a dose of 250 ⁇ g/week/mouse given slowly in a volume of 200 ⁇ l . Three-dimensional measurements of tumors were taken by caliper under anesthesia and used to calculate tumor volume (Pasqualini et al., supra , 1996).
  • tumor volume was smaller, on average by one order of magnitude, than in controls, which were a non-targeted CARAC-GG- D (KLAKLAK) 2 and a mixture of uncoupled D (KLAKLAK) 2 and CNGRC (SEQ ID NO: 8) peptides.
  • survival was longer in the HPP-1 treated groups than in control groups.
  • HPP-1 was also effective against tumors derived from the human melanoma cell line C8161 (Welch et al., Int. J. Cancer 47:227-237 (1991)). These results indicate that homing pro-apoptotic conjugates such as CNGRC-GG- D (KLAKLAK) 2 (HPP-1) have strong anti-tumor activities in vivo .
  • Retinal angiogenesis was oxygen-induced in newborn mice. Mice were subsequently treated with a single 13 ⁇ g intravenous dose (one animal per group) of vehicle; CDCRGDCFC-GG- D (KLAKLAK) 2 ; or a control mixture of unconjugated CDCRGDCFC (SEQ ID NO: 1) and D (KLAKLAK) 2 . Four days later, retinal neovessel number was determined for each treatment.
  • This example demonstrates methods for preparing a phage library and screening the library using in vivo panning to identify phage expressing tumor homing peptides .
  • Phage display libraries were constructed using the fuse 5 vector as described by Koivunen et al . ⁇ supra , 1995; Koivunen et al., supra, 1994b). Libraries encoding peptides designated CX 5 C (SEQ ID NO: 9), CX 6 C (SEQ ID NO: 10) , CX 7 C (SEQ ID NO: 11) and CX 3 CX 3 CX 3 C (SEQ ID NO: 12) were prepared, where "C" indicates cysteine and "X N " indicates the given number of individually selected amino acids. These libraries can display cyclic peptides when at least two cysteine residues are present in the peptide. In addition, a library that did not contain defined cysteine residues also was constructed. Such a library results in the production primarily of linear peptides, although cyclic peptides also can occur due to random probability.
  • a biased library based on the sequence CXXXNGRXX also was constructed. Furthermore, in some cases the CXXXNGRXX (SEQ ID NO: 13) library was further biased by in the incorporation of cysteine residues flanking the NGR sequence, i.e., CXXCNGRCX (SEQ ID NO: 14; see Table 2).
  • the libraries containing the defined cysteine residues were generated using oligonucleotides constructed such that "C” was encoded by the codon TGT and "X N " was encoded by NNK, where "N” is equal molar mixtures of A, C, G and T, and where "K” is equal molar mixtures of G and T.
  • the peptide represented by CX 5 C can be represented by an oligonucleotide having the sequence TGT (NNK) 5 TGT (SEQ ID NO: 14) . Oligonucleotides were made double stranded by 3 cycles of PCR amplification, purified and ligated to the nucleic acid encoding the gene III protein in the fuse 5 vector such that, upon expression, the peptide is present as a fusion protein at the N-terminus of the gene III protein.
  • the vectors were transfected by electroporation into MC1061 cells. Bacteria were cultured for 24 hr in the presence of 20 ⁇ g/ml tetracycline, then phage were collected from the supernatant by precipitation twice using polyethylene glycol. Each library contained about 5 x 10 9 to 5 x 10 14 transducing units (TU; individual recombinant phage) .
  • mice were transplanted into mice as described in Examples V and VI, below.
  • a mixture of phage libraries containing 1 x 10 9 to 1 x 10 14 TU was diluted in 200 ⁇ l DMEM and injected into the tail vein of anesthetized mice (AVERTIN (0.015 ml/g) ; see U.S. Patent No. 5,622,699; Pasqualini and Ruoslahti, supra, 1996). After 1-4 minutes, mice were snap frozen in liquid nitrogen.
  • DMEM-PI DMEM containing protease inhibitors (PI); phenylmethylsulfonyl fluoride (PMSF; 1 mM) , aprotinin (20 ⁇ g/ml), leupeptin (1 ⁇ g/ml)
  • mice were anesthetized with AVERTIN, then the heart was exposed and a 0.4 mm needle connected through a 0.5 mm cannula to a 10 cc syringe was inserted into the left ventricle. An incision was made on the right atrium and 5 to 10 ml of DMEM was slowly administered, perfusing the whole body over about a 5 to 10 min period. Efficiency of the perfusion was monitored directly by histologic analysis .
  • Tumor and organ samples were washed 3 times with ice cold DMEM-PI containing 1% bovine serum albumin (BSA) , then directly incubated with 1 ml K91-kan bacteria for 1 hr.
  • BSA bovine serum albumin
  • Ten ml NZY medium containing 0.2 ⁇ g/ml tetracycline (NZY/tet) was added to the bacterial culture, the mixture was incubated in a 37°C shaker for 1 hr, then 10 ⁇ l or 100 ⁇ l aliquots were plated in agar plates containing 12.5 ⁇ g/ml tetracycline (tet/agar) .
  • This example demonstrates that in vivo panning can be performed against a breast tumor to identify tumor homing peptides that home to various tumors.
  • Human 435 breast carcinoma cells (Price et al., Cancer Res. 50:717-721 (1990)) were inoculated into the mammary fat pad of nude mice. When the tumors attained a diameter of about 1 cm, either a phage targeting experiment was performed, in which phage expressing a specific peptide were administered to the tumor bearing mouse, or in vivo panning was performed.
  • the breast tumor bearing mice were injected with 1 x 10 9 phage expressing a library of CX 3 CX 3 CX 3 C (SEQ ID NO: 12) peptides, where X 3 indicates three groups of independently selected, random amino acids.
  • the phage were allowed to circulate for 4 min, then the mice were anesthetized, snap frozen in liquid nitrogen while under anesthesia, and the tumor was removed. Phage were isolated from the tumor and subjected to two additional rounds of in vivo panning.
  • CGRECPRLCQSSC (2*) CNGRCVSGCAGRC (3) CGEACGGQCALPC (20) IWSGYGVYW (21) PSCAYMCIT (22) WESLYFPRE (23) SKVLYYNWE (24) CGLMCQGACFDVC (25) CERACRNLCREGC (26) CPRGCLAVCVSQC (27) CKVCNGRCCG (28) CEMCNGRCMG 29) CPLCNGRCAL 30) CPTCNGRCVR (31) CGVCNGRCGL 32) CEQCNGRCGQ 33) CRNCNGRCEG (34) CVLCNGRCWS 35) CVTCNGRCRV 36) CTECNGRCQL (37) CRTCNGRCLE 38) CETCNGRCVG 39) CAVCNGRCGF (40) CRDLNGRKVM 41) CSCCNGRCGD 42) CWGCNGRCRM (43) CPLCNGRCAR 44) CKSCNGRCLA 45) CVPCNGRCHE (46) CQSCNGRCVR 47) CRTCNGRCQV 48) CVQCN
  • CVMVRDGDC 84) CVRIRPC 85 CQLAAVC (86
  • CAQLLQVSC (102) CYPADPC 103) CKALSQAC (104) CTDYVRC (105) CGETMRC 106) - numbers in parentheses indicate SEQ ID NO:
  • phage were quantitated and the peptide sequences expressed by the cloned phage were determined. The cloned phage expressed various different peptides, including those shown in Table 2.
  • CX 7 C SEQ ID NO: 11
  • CX 5 C SEQ ID NO: 9 libraries were screened and breast tumor homing peptides were identified (Table 2).
  • Human 435 breast carcinoma cells were inoculated into the mammary fat pad of nude mice. When the tumors attained a diameter of about 1 cm, phage expressing a specific RGD-containing peptide were administered to the tumor bearing mouse. Similar results to those discussed below also were obtained with nude mice bearing tumors formed by implantation of human melanoma C8161 cells or by implantation of mouse B16 melanoma cells.
  • This example provides a method of identifying the localization of tumor homing molecules by immunohistologic examination.
  • phage-phage a tumor homing peptide
  • histologic sections obtained either 5 min or 24 hr after administration of phage expressing a tumor homing peptide ("peptide-phage") to a tumor bearing mouse.
  • peptide-phage a tumor homing peptide
  • mice were perfused with DMEM and various organs, including the tumor, were removed and fixed in Bouin' s solution.
  • no peptide-phage remains in the circulation and, therefore, perfusion was not required.
  • Histologic sections were prepared and reacted with anti-Ml3 (phage) antibodies (Pharmacia Biotech; see U.S. Patent No.
  • phage expressing the tumor homing peptide were administered intravenously to mice bearing the breast tumor.
  • RGD phage were administered to mice bearing a mouse melanoma or a human Kaposi's sarcoma. Circulation of the phage was terminated and mice were sacrificed as described above and samples of the tumor and of skin adjacent to the tumor, brain, kidney, lung and liver were collected.
  • Immunohistochemical staining for the phage showed accumulation of the RGD phage in the blood vessels present in the breast tumor as well as in the melanoma and the Kaposi's sarcoma, whereas little or no staining was observed in the control organs.
  • CNGRCVSGCAGRC SEQ ID NO: 3; "NGR phage”
  • NGR phage or control phage which do not express a peptide, were administered to mice bearing tumors formed by the MDA-MB-435 breast carcinoma or by a human SLK Kaposi's sarcoma xenograft, then the mice were sacrificed as described above and tumors were collected as well as control organs, including brain, lymph node, kidney, pancreas, uterus, mammary fat pad, lung, intestine, skin, skeletal muscle, heart and epithelium of the renal calices, bladder and ureter. Histological samples were prepared and examined by immunostaining as described above.
  • CVLNGRMEC (SEQ ID NO: 7), to tumor bearing mice. Also, as discussed below, similar results were obtained using phage expressing the GSL tumor homing peptide, CLSGSLSC
  • tumor homing peptides selectively home to tumors, particularly to the vasculature in the tumors and that tumor homing peptides identified, for example, by in vivo panning against a breast carcinoma also selectively home to other tumors, including Kaposi's sarcoma and melanoma.
  • immunohistochemical analysis provides a convenient assay for identifying the localization of phage expressing tumor homing peptides.
  • the general applicability of the in vivo panning method to identify tumor homing peptides was examined by performing in vivo panning against an implanted mouse melanoma tumor.
  • mice bearing a melanoma were produced by implantation of B16B15b mouse melanoma cells, which produce highly vascularized tumors.
  • B16B15b mouse melanoma cells were injected subcutaneously into the mammary fat pad of nude mice (2 months old) and tumors were allowed to grow until the diameter was about 1 cm.
  • In vivo panning was performed as disclosed above. Approximately 1 x 10 12 transducing units of phage expressing the CX 5 C (SEQ ID NO: 9), CX 6 C (SEQ ID NO: 10) or CX 7 C (SEQ ID NO: 11) library were injected, iv, and allowed to circulate for 4 min. Mice then were snap frozen in liquid nitrogen or perfused through the heart while under anesthesia, tumor tissue and brain (control organ) were removed, and phage were isolated as described above. Three rounds of in vivo panning were performed.
  • GPSRVGG (124) WWSGLEA 125) LGTDVRQ (126)
  • GLLLVVP (130) FAATSAE 131) WCCRQFN (132)
  • the amino acid sequences were determined for the inserts in 89 cloned phage recovered from the B16B15b tumors.
  • the peptides expressed by these phage were represented by two predominant sequences, CLSGSLSC (SEQ ID NO: 4; 52% of the clones sequenced) and WGTGLC (SEQ ID NO: 18; 25% of the clones; see Table 3). Reinfection of phage expressing one of the selected peptides resulted in approximately three-fold enrichment of phage homing to the tumor relative to brain.
  • Immunostaining was evident in the melanoma obtained from a mouse injected with phage expressing the CLSGSLSC (SEQ ID NO: 4) tumor homing peptide. Staining of the melanoma generally was localized to the blood vessels within the tumor, although some staining also was present in the tumor parenchyma. Essentially no staining was observed in a tumor obtained from a mouse injected with the insertless control phage or in skin or in kidney samples obtained from mice injected with either phage. However, immunostaining was detected in the liver sinusoids and in spleen, indicating that phage can be trapped nonspecifically in organs containing RES.
  • in vivo panning was performed in mice bearing a SLK human Kaposi's sarcoma. Tumor homing peptides were identified and are disclosed in Table 4. Together, these results demonstrate that the in vivo panning method is a generally applicable method for screening a phage library to identify phage expressing tumor homing peptides.
  • TDCTPSRCT 150* SWCQFEKCL (151) VPCRFKQCW (152) CTAMRNTDC (153) CRESLKNC (154) CMEMGVKC (155) VTCRSLMCQ (156) CNNVGSYC (157) CGTRVDHC (158) CISLDRSC (159) CAMVSMED (160) CYLGVSNC (161) CYLVNVDC (162) CIRSAVSC (163) LVCLPPSCE (164) RHCFSQWCS (165) FYCPGVGCR (166) ISCAVDACL (167) EACEMAGCL (168) PRCESQLCP (169) RSCIKHQCP (170) QWCSRRWCT (171) MFCRMRSCD (172) GICKDLWCQ (173) NACESAICG (174) APCGLLACI (175) NRCRGVSCT (176) FPCEGKKCL (177) ADCRQKPCL (178) FGCVMASCR (179) AGCINGLCG (180) RSCAEPWCY (181) DTCRALRCN (182) KGCGTRQCW (109) GRCVDGGCT
  • chimeric peptide SMSIARL-GG- D (KLAKLAK) 2 can selectively induce apoptosis in prostate tissue following systemic administration and can prolong survival of animals with experimental prostate cancer.
  • WHQPL ( !223) SMSIARL* (207) RGRWLAL* (224; QVEEFPC (225) LWLSGNW (226) GPMLSVM (227) WTFLERL (228) VLPGGQW (229) REVKES (230) RTPAAVM (231) GEWLGEC (232) PNPLMPL (233) SLWYLGA (234) YVGGWEL (235)
  • biotin-conjugated SMSIARL (SEQ ID NO: 207) synthetic peptide was shown to home to the prostate. Briefly, one mg of biotin-conjugated prostate-homing peptide SMSIARL (SEQ ID NO: 207), or biotin-labeled control peptide CARAC (SEQ ID NO: 208), was injected intravenously into a mouse, which was sacrificed 10 minutes later. The prostate and other tissues were collected, sectioned and processed for staining with avidin-peroxidase. Biotin staining was found mostly in the lumen of the glands, rather than in the vasculature, as soon as 10 minutes after systemic injection of the conjugate.
  • SMSIARL peptide SEQ ID NO: 207
  • D pro-apoptotic peptide
  • SMSIARL-GG- D (KLAKLAK) 2 chimeric peptide or control material was administered as a single dose of 250 ⁇ g peptide/mouse, and TUNEL staining was performed on tissues obtained 24 hours later.
  • mice injected with the SMSIARL-GG- D (KLAKLAK) 2 chimera showed increased apoptosis in their prostates and, in particular, in capillary endothelium and the basal myoepithelial cells of prostate glands.
  • TRAMP mice develop prostate cancer under the influence of a transgene as described in Gingrich et al., supra , 1996.
  • SMSIARL-GG- D (KLAKLAK) 2 chimeric peptide was assayed for the ability to suppress cancer development in the TRAMP mice.
  • Treatment was initiated at 12 weeks of age with mice (10 per group) receiving SMSIARL-GG- D (KLAKLAK) 2 peptide or control peptide at 250 ⁇ g/dose every other week for a total of 10 doses.
  • Four mice, which had no visible tumor, were eliminated from the SMSIARL-GG- D (KLAKLAK) 2 group after dying within minutes after the injection.
  • mice As shown in Figure 8, SMSIARL-GG- D (KLAKLAK) 2 -treated mice survived longer than mice treated with controls, which were vehicle, D (KLAKLAK) 2 peptide alone, or SMSIARL peptide (SEQ ID NO: 207) alone.
  • controls which were vehicle, D (KLAKLAK) 2 peptide alone, or SMSIARL peptide (SEQ ID NO: 207) alone.
  • treatment of TRAMP mice with targeted pro-apoptotic SMSIARL-GG- D (KLAKLAK) 2 compound over a period of several months resulted in an apparent increase in survival of the treated mice relative to control mice.
  • SMSIARL SEQ ID NO: 207
  • phage bind to the endothelium of human prostate blood vessels (see panels a and b) .
  • No endothelial staining was seen with phage that contain no peptide insert (panel c) .
  • SMSIARL (SEQ ID NO: 207) -phage staining was inhibited when soluble SMSIARL peptide SEQ ID NO: 207 was included in the overlay at 0.3 mg/ml.
  • the results shown in Figure 9 indicate that at least some tumors retain the receptor for the homing peptide.
  • peptide SEQ ID NO: 207 can bind to vessels in intraprostatic cancer, while blood vessels in several other human tissues were not stained by the SMSIARL (SEQ ID NO: 207) phage.

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  • Engineering & Computer Science (AREA)
  • Veterinary Medicine (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • Molecular Biology (AREA)
  • Pharmacology & Pharmacy (AREA)
  • Animal Behavior & Ethology (AREA)
  • Public Health (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Genetics & Genomics (AREA)
  • Biophysics (AREA)
  • Biochemistry (AREA)
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  • Gastroenterology & Hepatology (AREA)
  • Epidemiology (AREA)
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  • Oncology (AREA)
  • Immunology (AREA)
  • Cell Biology (AREA)
  • Urology & Nephrology (AREA)
  • Peptides Or Proteins (AREA)
  • Medicines That Contain Protein Lipid Enzymes And Other Medicines (AREA)

Abstract

L'invention concerne un peptide chimère de ciblage de la prostate comportant une activité pro-apoptotique. Dans une forme de réalisation préférée, le peptide chimère de ciblage de la prostate pro-apoptotique contient la séquence SMSIARL-GG-D(KLAKLAK)2. L'invention concerne aussi des procédés d'utilisation de ces peptides chimères pour traiter des patients atteints de cancer de la prostate.
EP01942640A 2000-01-21 2001-01-16 Peptides chimeres de ciblage de la prostate comportant une activite pro-apoptotique Ceased EP1250355A1 (fr)

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Application Number Priority Date Filing Date Title
US48958200A 2000-01-21 2000-01-21
US489582 2000-01-21
PCT/US2001/001362 WO2001053342A1 (fr) 2000-01-21 2001-01-16 Peptides chimeres de ciblage de la prostate comportant une activite pro-apoptotique

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EP1250355A1 true EP1250355A1 (fr) 2002-10-23

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EP (1) EP1250355A1 (fr)
JP (1) JP2003520808A (fr)
CN (1) CN1419565A (fr)
AU (1) AU2001229494A1 (fr)
WO (1) WO2001053342A1 (fr)

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US20040170955A1 (en) 2000-09-08 2004-09-02 Wadih Arap Human and mouse targeting peptides identified by phage display
US7452964B2 (en) 2001-09-07 2008-11-18 Board Of Regents, The University Of Texas System Compositions and methods of use of targeting peptides against placenta and adipose tissues
CA2458047A1 (fr) * 2001-09-07 2003-03-20 Board Of Regents, The University Of Texas System Compositions et procedes d'utilisation de peptides de ciblage contre les tissus adipeux et placentaires
WO2004011595A2 (fr) * 2002-07-26 2004-02-05 Institut Pasteur Vecteurs destines au transfert de molecules d'interet dans des cellules cibles
CA2519826A1 (fr) 2003-03-24 2004-10-07 Nippon Medical School Foundation Gene chimere induisant la mort cellulaire et agissant specifiquement sur le cancer, et produit de gene chimere
CA2534708A1 (fr) * 2003-08-05 2005-02-17 Wisconsin Alumni Research Foundation Fusions de vecteurs cibles pour administrer des agents chimiotherapeutiques
ATE538806T1 (de) * 2004-09-07 2012-01-15 Burnham Inst Peptide mit spezifischem sitz in herzgefässen und verwandte konjugate und verfahren
JP5384948B2 (ja) * 2007-02-09 2014-01-08 ジェノミディア株式会社 新規ポリペプチド及びそれを有効成分として含有する抗菌剤
CN101157729B (zh) * 2007-10-23 2011-01-12 南京大学 一种肿瘤坏死因子相关凋亡配体变体及其应用
US11559580B1 (en) 2013-09-17 2023-01-24 Blaze Bioscience, Inc. Tissue-homing peptide conjugates and methods of use thereof
CN104974227B (zh) * 2014-04-04 2019-04-23 中国科学院苏州纳米技术与纳米仿生研究所 阳离子双亲性膜靶向α-螺旋多肽及其应用
US9029319B1 (en) * 2014-08-04 2015-05-12 Centaur, Inc. Water buffalo derived peptide antibiotic therapies
US11090358B2 (en) 2015-09-09 2021-08-17 Fred Hutchinson Cancer Research Center Cartilage-homing peptides
CN110267970A (zh) 2016-11-16 2019-09-20 比奥马林技术公司 用于靶向各种选定器官或组织的物质
CN106699896B (zh) * 2016-12-05 2020-06-05 华中科技大学同济医学院附属协和医院 一种可自组装成水凝胶的肿瘤杀伤性多肽及其应用
US11180535B1 (en) 2016-12-07 2021-11-23 David Gordon Bermudes Saccharide binding, tumor penetration, and cytotoxic antitumor chimeric peptides from therapeutic bacteria
CN106632688B (zh) * 2016-12-23 2020-06-05 华中科技大学同济医学院附属协和医院 一种用于修饰微泡的多肽以及靶向gbm的药物制剂
EP3595699A4 (fr) 2017-03-16 2020-12-23 Blaze Bioscience, Inc. Conjugués peptidiques d'écotropisme du cartilage et leurs méthodes d'utilisation

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EP1015884B1 (fr) * 1997-09-10 2008-08-06 The Burnham Institute Procedes relatifs a l'identification de molecules capables de rallier des systemes vasculaires angiogeniques dans les tumeurs
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AU2001229494A1 (en) 2001-07-31
WO2001053342A1 (fr) 2001-07-26
CN1419565A (zh) 2003-05-21
WO2001053342A9 (fr) 2002-10-31
JP2003520808A (ja) 2003-07-08

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