TREATMENT, DIAGNOSIS AND IMAGING OF DISEASE
The present invention relates to genes whose expression is up-regulated in Mantle cell lymphomas (MCL) and use of these genes or gene products, or molecules which bind thereto, in imaging and/or diagnosis and/or treatment of MCL.
The term lymphoma refers to all the malignancies of the lymphocytes, with B and T cell malignancies being the most commonplace. The classification of lymphomas is still under debate and far from conclusive. The current classification being used is the Revised European American Classification of Lymphomas (Harris et al., 1994, Blood 84: 1361-1392). However, this system needs to be further divided to allow as precise diagnosis as possible, thereby permitting the optimal treatment for the patients.
Several gene expression studies of different types of B-cell lymphomas have been published. For example, Golub et al. (1999) Science 286:531-537 have shown that acute myeloid leukaemia (AML) and acute lymphoblastic leukaemia (ALL) can be distinguished based on their gene expression analysis. In addition, Alizadeh et al. (2000) Nature 403:503-511 found two distinct types of diffuse large B-cell lymphoma (DLBCL) when analysing the gene expression of these tumours on the Lymphochip.
B-cells go through several differentiation stages during development. The immature B-cell migrates from bone-marrow to the lymph node where the naive B-cell is stimulated to migrate into the B-cell follicles, forming Germinal Centres, before finally differentiating into an antibody secreting plasma cell. For each of these different stages a malignant counterpart has been found that resembles the normal B-cell origin (Pascual et al., 1997, Baillieres Clin Haematol 10:525-538).
Mantle cell lymphomas (MCLs) are believed to derive from a naive B-cell, although the relationship with the CD5+ B-1 cells also has been discussed (Pascual et al., supra; Capello et al., 2000, Haematologica 85:195-201). MCLs are indolent and show no somatic mutation of their immunoglobulin genes, thus resembling their naϊve B-cell origin. The median age of disorder for MCL patients is 60 years and the median survival is 2 to 5 years with a poor response to conventional therapeutic regimens (Weisenburger et al., 2000, Am J Hematol 64:190-196). Seventy per cent of the patients have bone marrow involvement and the male to female predominance is 3: 1 (Kurtin, 1998, Adv Anat Pathol 5:376-398). MCL cells express the pan-B-cell markers CD 19, CD20, CD22, CD79a and CD79b and are negative for CD 10 and CD23 (Kurtin, 1998, Adv Anat Pathol 5:376-398). MCL tumours can grow in three different growth patterns, mantle zone, nodular and diffuse pattern. There are also several morphological variants with different median survival (monocytoid B-cell like, pleomorphic or anaplastic variant, large cell variant and blastoid variant) that fill the criteria for being designated as MCLs (CD20+ neoplasms that are CD43+, CD5 , CD23", CD 10" and cyclin DI positive) (Kurtin, 1998, Adv Anat Pathol 5:376-398). Follicular dendritic cell meshwork positive for CD21, CD23 and CD35 can often be seen in the MCL tumour
tissue (Kurtin, 1998, Adv Anat Pathol 5:376-398). The t(l l:14)(ql3:q32) translocation that leads to the translocation of bcl-1 and over expression of cyclin DI is a characteristic feature of MCL and is seen rarely in other types of non-Hodgkin's lymphoma (Kurtin, 1998, Adv Anat Pathol 5:376-398; Bentz et al., 2000, Genes Chromosomes Cancer 27:285-294). Cyclin DI promotes the Gl to S phase transition and is believed to be one of the main features contributing to the malignant behaviour of MCL.
MCL is recognised as one of the most severe forms of lymphoma, generally exhibiting a resistance to conventional chemotherapy and a rapid clinical progression. Hence, there is a need for improved therapies for the treatment of MCL and improved diagnostic methods.
A first aspect of the invention provides a compound comprising (i) a binding moiety which selectively binds to one of the proteins or polypeptides listed in Table 1 and (ii) a further moiety for the treatment and/or imaging and/or diagnosis of MCL.
A second aspect of the invention provides a compound according to the first aspect of the invention for use as a medicament. Preferably, the medicament is for the imaging, diagnosis, prognosis or treatment of MCL.
A third aspect of the invention provides a use of a compound according to the first aspect of the invention in the manufacture of an agent for imaging MCL cells in a body of an individual. Thus, the invention provides the use of a compound according to the first aspect of the invention for imaging MCL cells, either in vivo or in vitro.
An fourth aspect of the invention provides a use of a compound according to the first aspect of the invention in the manufacture of a diagnostic or prognostic agent for MCL. Thus, the invention provides the use of a compound according to the first aspect of the invention for diagnosing or prognosing MCL.
A fifth aspect of the invention is the use of a compound according to the first aspect of the invention wherein in the manufacture of a medicament for treating MCL. Thus, the invention provides the use of a compound according to the first aspect of the invention for treating MCL. It will be appreciated by persons skilled in the art that the medicament may be used for prophylactic and therapeutic purposes.
By "selectively bind" we include binding moieties which bind at least 10-fold more strongly to one of the proteins listed in Table 1 than to another polypeptide; preferably at least 50-fold more strongly and more preferably at least 100-fold more strongly.
TABLE 1
Preferably, the binding moiety selectively binds to a polypeptide comprising or consisting of an amino acid sequence selected from the group consisting of SEQ ID Nos 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 22, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 42, 44, 49, 51, 53, 55, 59, 60, 63, 67, 69, 71, 74, 76, 78, 83, 85, 87, 91, 95, 97, 100, 102, 108 and 110 or natural variants thereof.
By "natural variants" we include, for example, allelic variants. Typically, these will vary from the given sequence by only one or two or three, and
typically no more than 10 or 20 amino acid residues. Typically, the variants have conservative substitutions.
Variants of the above polypeptides include polypeptides comprising a sequence with at least 60% identity to the amino acid sequences of SEQ ID Nos 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 22, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 42, 44, 49, 51, 53, 55, 59, 60, 63, 67, 69, 71, 74, 76, 78, 83, 85, 87, 91, 95, 97, 100, 102, 108 and 110, preferably at least 70% or 80% or 85% or 90% identity to said sequences, and more preferably at least 95%, 96%, 97%, 98% or 99% identity to said amino acid sequences.
Percent identity can be determined by, for example, the LALIGN program (Huang and Miller, Adv. Appl. Math. (1991) 12:337-357) at the Expasy facility site (http : //www . ch. embnet. or g/software/L ALIGN_form.html using as parameters the global alignment option, scoring matrix BLOSUM62, opening gap penalty -14, extending gap penalty -4. Alternatively, the percent sequence identity between two polypeptides may be determined using suitable computer programs, for example the GAP program of the University of Wisconsin Genetic Computing Group and it will be appreciated that percent identity is calculated in relation to polypeptides whose sequence has been aligned optimally.
Conveniently, the binding moiety selectively binds to a polypeptide encoded by a nucleotide sequence selected from the group consisting of SEQ ID Nos 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 24, 26, 28, 30, 32, 34, 36, 38, 40, 43, 45, 46, 47,
48, 50 , 52, 54, 56, 57, 58, 61, 62, 64, 65, 66, 68, 70, 72, 73, 75, 77, 79, 80, 81,
82, 84, 86, 88, 89, 90, 92, 93, 94, 96, 98, 99, 101, 103, 104, 105, 106, 107, 109 and 111 or natural variants thereof.
Preferably, the polypeptide is a human polypeptide.
Advantageously, the binding moiety and further moiety are covalently attached.
In a preferred embodiment of the first aspect of the invention, the binding moiety is an antibody.
By "antibody" we include not only whole immunoglobulin molecules but also fragments thereof such as Fab, F(ab')2, Fv and other fragments thereof that retain the antigen-binding site. Similarly the term "antibody" includes genetically engineered derivatives of antibodies such as single chain Fv molecules (scFv) and single domain antibodies (dAbs). The term also includes antibody-like molecules which may be produced using phage-display techniques or other random selection techniques for molecules which bind to one of the proteins identified in Table 1.
The variable heavy (VH) and variable light (VL) domains of the antibody are involved in antigen recognition, a fact first recognised by early protease digestion experiments. Further confirmation was found by "humanisation" of rodent antibodies. Variable domains of rodent origin may be fused to constant domains of human origin such that the resultant antibody retains the antigenic specificity of the rodent parented antibody (Morrison et al (1984) Proc. Natl. Acad. Sci. USA 81, 6851-6855).
That antigenic specificity is conferred by variable domains and is independent of the constant domains is known from experiments involving the bacterial expression of antibody fragments, all containing one or more variable domains. These molecules include Fab-like molecules (Better et al (1988) Science 240, 1041); Fv molecules (Skerra et al (1988) Science 240, 1038); single-chain Fv (ScFv) molecules where the VH and VL partner domains are linked via a flexible oligopeptide (Bird et al (1988) Science 242, 423; Huston et al (1988) Proc. Natl. Acad. Sci. USA 85, 5879) and single domain antibodies (dAbs) comprising isolated V domains (Ward et al (1989) Nature 341, 544). A general review of the techniques involved in the synthesis of antibody fragments which retain their specific binding sites is to be found in Winter & Milstein (1991) Nature 349, 293-299.
By "ScFv molecules" we mean molecules wherein the VH and VL partner domains are linked via a flexible oligopeptide.
The advantages of using antibody fragments, rather than whole antibodies, are several-fold. The smaller size of the fragments may lead to improved pharmacological properties, such as better penetration to the target site. Effector functions of whole antibodies, such as complement binding, are removed. Fab, Fv, ScFv and dAb antibody fragments can all be expressed in and secreted from E. coli, thus allowing the facile production of large amounts of the said fragments.
Whole antibodies, and F(ab')2 fragments are "bivalent". By "bivalent" we mean that the said antibodies and F(ab')2 fragments have two antigen combining sites. In contrast, Fab, Fv, ScFv and dAb fragments are monovalent, having only one antigen combining site.
Although the antibody may be a polyclonal antibody, it is preferred if it is a monoclonal antibody. In some circumstances, particularly if the antibody is going to be administered repeatedly to a human patient, it is preferred if the monoclonal antibody is a human monoclonal antibody or a humanised monoclonal antibody.
Suitable monoclonal antibodies may be prepared by known techniques, for example those disclosed in "Monoclonal Antibodies; A manual of techniques ", H Zola (CRC Press, 1988) and in "Monoclonal Hybridoma Antibodies: Techniques and Application", SGR Hurrell (CRC Press, 1982). Polyclonal antibodies may be produced which are polyspecific or monospecific. It is preferred that they are monospecific.
Chimaeric antibodies are discussed by Neuberger et al (1998, 8th International Biotechnology Symposium Part 2, 792-799).
Suitably prepared non-human antibodies can be "humanised" in known ways, for example by inserting the CDR regions of mouse antibodies into the framework of human antibodies.
The antibodies may be human antibodies in the sense that they have the amino acid sequence of human antibodies with specificity for one of the proteins identified in Table 1 but they may be prepared using methods known in the art that do not require immunisation of humans. For example, transgenic mice are available which contain, in essence, human immunoglobulin genes (see Vaughan et al (1998) Nature Biotechnol. 16, 535-539.
In an alternative embodiment, the binding moiety is a peptide. Peptides binding moieties can be identified by means of a screen. A suitable method or screen for identifying peptides or other molecules which selectively bind a target protein or polypeptide may comprise contacting the target protein or polypeptide with a test peptide or other molecule under conditions where binding can occur, and then determining if the test molecule or peptide has bound the target protein or peptide. Methods of detecting binding between two moieties are well known in the art of biochemistry. Preferably, the known technique of phage display is used to identify peptides or other ligand molecules suitable for use as binding moieties. An alternative method includes the yeast two hybrid system.
The ftirther moiety may be any further moiety which confers on the compound a useful property with respect to the treatment or imaging or diagnosis of MCL. In particular, the further moiety is one which is useful in killing or imaging cells associated with MCL. Preferably, the ftirther moiety is one which is able to kill the cells to which the compound is targeted.
In a preferred embodiment of the invention the further moiety is directly or indirectly cytotoxic. In particular the further moiety is preferably directly or indirectly toxic to MCL cells.
By "directly cytotoxic" we include the meaning that the moiety is one which on its own is cytotoxic. By "indirectly cytotoxic" we include the meaning that the moiety is one which, although is not itself cytotoxic, can induce cytotoxicity, for example by its action on a further molecule or by further action on it.
In one embodiment the cytotoxic moiety is a cytotoxic chemotherapeutic agent. Cytotoxic chemotherapeutic agents are well known in the art.
Cytotoxic chemotherapeutic agents, such as anticancer agents, include: alkylating agents including nitrogen mustards such as mechlorethamine (HN2), cyclophosphamide, ifosfamide, melphalan (L-sarcolysin) and chlorambucil; ethylenimines and methylmelamines such as hexamethylmelamine, thiotepa; alkyl sulphonates such as busulfan; nitrosoureas such as carmustine (BCNU), lomustine (CCNU), semustine (methyl-CCNU) and streptozocin (streptozotocin); and triazenes such as decarbazine (DTIC; dimethyltriazenoimidazole- carboxamide); Antimetabolites including folic acid analogues such as methotrexate (amethopterin); pyrimidine analogues such as fluorouracil (5- fluorouracil; 5-FU), floxuridine (fluorodeoxyuridine; FUdR) and cytarabine
(cytosine arabinoside); and purine analogues and related inhibitors such as mercaptopurine (6-mercaptopurine; 6-MP), thioguanine (6-thioguanine; TG) and pentostatin (2'-deoxycoformycin). Natural Products including vinca alkaloids such as vinblastine (VLB) and vincristine; epipodophyllotoxins such as etoposide
and teniposide; antibiotics such as dactinomycin (actinomycin D), daunorubicin (daunomycin; rubidomycin), doxorubicin, bleomycin, plicamycin (mithramycin) and mitomycin (mitomycin C); enzymes such as L-asparaginase; and biological response modifiers such as interferon alphenomes. Miscellaneous agents including platinum coordination complexes such as cisplatin (cz's-DDP) and carboplatin; anthracenedione such as mitoxantrone and anthracycline; substituted urea such as hydroxyurea; methyl hydrazine derivative such as procarbazine (N- methylhydrazine, MIH); and adrenocortical suppressant such as mitotane (o,p - DDD) and aminoglutethimide; taxol and analogues/derivatives; and hormone agonists/antagonists such as flutamide and tamoxifen.
Various of these agents have previously been attached to antibodies and other target site-delivery agents, and so compounds of the invention comprising these agents may readily be made by the person skilled in the art. For example, carbodiimide conjugation (Bauminger & Wilchek (1980) Methods Enzymol. 70, 151-159; incorporated herein by reference) may be used to conjugate a variety of agents, including doxorubicin, to antibodies or peptides.
Carbodiimides comprise a group of compounds that have the general formula R1-N=C=N-R2, where Rt and R2 can be aliphatic or aromatic, and are used for synthesis of peptide bonds. 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.
The water soluble carbodiimide, l-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) is particularly useful for conjugating a functional moiety to a binding moiety and may be used to conjugate doxorubicin to tumour
homing peptides. The conjugation of doxorubicin and a binding moiety requires the presence of an amino group, which is provided by doxorubicin, and a carboxyl group, which is provided by the binding moiety such as an antibody or peptide.
In addition to using carbodiimides for the direct formation of peptide bonds, EDC also can be used to prepare active esters such as N-hydroxysuccinimide (NHS) ester. 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. The use of EDC and NHS in combination is commonly used for conjugation in order to increase yield of conjugate formation (Bauminger & Wilchek, supra, 1980).
Other methods for conjugating a functional moiety to a binding moiety also can be used. For example, sodium periodate oxidation followed by reductive alkylation of appropriate reactants can be used, as can glutaraldehyde cross- linking. However, it is recognised that, regardless of which method of producing a conjugate of the invention is selected, a determination must be made that the binding moiety maintains its targeting ability and that the functional moiety maintains its relevant function.
In a ftirther embodiment of the invention, the cytotoxic moiety is a cytotoxic peptide or polypeptide moiety by which we include any moiety which leads to cell death. Cytotoxic peptide and polypeptide moieties are well known in the art and include, for example, ricin, abrin, Pseudomonas exotoxin, tissue factor and the like. Methods for linking them to targeting moieties such as antibodies are also known in the art. The use of ricin as a cytotoxic agent is described in
Burrows & Thorpe (1993) Proc. Natl. Acad. Sci. USA 90, 8996-9000, incorporated herein by reference, and the use of tissue factor, which leads to localised blood clotting and infarction of a tumour, has been described by Ran et al (1998) Cancer Res. 58, 4646-4653 and Huang et al (1997) Science 275, 547-550. Tsai et al (1995) Dis. Colon Rectum 38, 1067-1074 describes the abrin A chain conjugated to a monoclonal antibody and is incorporated herein by reference. Other ribosome inactivating proteins are described as cytotoxic agents in WO 96/06641. Pseudomonas exotoxin may also be used as the cytotoxic polypeptide moiety (see, for example, Aiello et al (1995) Proc. Natl. Acad. Sci. USA 92, 10457-10461; incoφorated herein by reference).
Certain cytokines, such as TNFα and IL-2, may also be useful as cytotoxic agents.
Certain radioactive atoms may also be cytotoxic if delivered in sufficient doses. Thus, the cytotoxic moiety may comprise a radioactive atom which, in use, delivers a sufficient quantity of radioactivity to the target site so as to be cytotoxic. Suitable radioactive atoms include phosphoras-32, iodine- 125, iodine-131, indium-I l l, rhenium-186, rhenium-188 or yttrium-90, or any other isotope which emits enough energy to destroy neighbouring cells, organeUes or nucleic acid. Preferably, the isotopes and density of radioactive atoms in the compound of the invention are such that a dose of more than 4000 cGy (preferably at least 6000, 8000 or 10000 cGy) is delivered to the target site and, preferably, to the cells at the target site and their organeUes, particularly the nucleus.
The radioactive atom may be attached to the binding moiety in known ways. For example EDTA or another chelating agent may be attached to the binding moiety and used to attach mIn or 90Y. Tyrosine residues may be directly labelled with 125I or 131I.
The cytotoxic moiety may be a suitable indirectly cytotoxic polypeptide. In a particularly preferred embodiment, the indirectly cytotoxic polypeptide is a polypeptide which has enzymatic activity and can convert a relatively nontoxic prodrug into a cytotoxic drug. When the binding moiety is an antibody this type of system is often referred to as ADEPT (Antibody-Directed Enzyme Prodrug Therapy). The system requires that the binding moiety locates the enzymatic portion to the desired site in the body of the patient {i.e. the MCL cells) and after allowing time for the enzyme to localise at the site, administering a prodrug which is a substrate for the enzyme, the end product of the catalysis being a cytotoxic compound. The object of the approach is to maximise the concentration of drug at the desired site and to minimise the concentration of drug in normal tissues (see Senter, P.D. et al (1988) "Anti- tumour effects of antibody-alkaline phosphatase conjugates in combination with etoposide phosphate" Proc. Natl. Acad. Sci. USA 85, 4842-4846; Bagshawe (1987) Br. J. Cancer 56, 531-2; and Bagshawe, K.D. et al (1988) "A cytotoxic agent can be generated selectively at cancer sites" Br. J. Cancer. 58, 700-703.)
Clearly, any binding moiety with specificity for one of the proteins identified in Table 1 may be used in place of an antibody in this type of directed enzyme prodrug therapy system.
The enzyme and prodrug of the system using a targeted enzyme as described herein may be any of those previously proposed. The cytotoxic substance may be any existing anti-cancer drug such as an alkylating agent; an agent which intercalates in DNA; an agent which inhibits any key enzymes such as dihydrofolate reductase, thymidine synthetase, ribonucleotide reductase, nucleoside kinases or topoisomerase; or an agent which effects cell death by interacting with any other cellular constituent. Etoposide is an example of a topoisomerase inhibitor.
Reported prodrug systems include: a phenol mustard prodrug activated by an E. coli β-glucuronidase (Wang et al, 1992 and Roffler et al, 1991); a doxorubicin prodrug activated by a human β-glucuronidase (Bosslet et al, 1994); further doxorubicin prodrugs activated by coffee bean α-galactosidase (Azoulay et al, 1995); daunorubicin prodrugs, activated by coffee bean α-D- galactosidase (Gesson et al, 1994); a 5-fluorouridine prodrug activated by an E. coli β-D-galactosidase (Abraham et al, 1994); and methotrexate prodrugs (e.g. methotrexate-alanine) activated by carboxypeptidase A (Kuefner et al, 1990, Vitols et al, 1992 and Vitols et al, 1995). These and others are included in the Table 2 below.
TABLE 2
(This table is adapted from Bagshawe (1995) Drug Dev. Res. 34, 220-230, from which full references for these various systems may be obtained; the taxol derivative is described in Rodrigues, M.L. et al (1995) Chemistry & Biology 2, 223).
Suitable enzymes for forming part of the enzymatic portion a compound of the invention include: exopeptidases, such as carboxypeptidases G, Gl and G2 (for glutamylated mustard prodrugs), carboxypeptidases A and B (for MTX-based
prodrugs) and aminopeptidases (for 2-α-aminocyl MTC prodrugs); endopeptidases, such as e.g. thrombolysin (for thrombin prodrugs); hydrolases, such as phosphatases (e.g. alkaline phosphatase) or sulphatases (e.g. aryl sulphatases) (for phosphylated or sulphated prodrugs); amidases, such as penicillin amidases and arylacyl amidase; lactamases, such as β-lactamases; glycosidases, such as β-glucuronidase (for β-glucuronomide anthracyclines), α- galactosidase (for amygdalin) and β-galactosidase (for β-galactose anthracycline); deaminases, such as cytosine deaminase (for 5FC); kinases, such as urokinase and thymidine kinase (for gancyclovir); reductases, such as nitroreductase (for CBI 954 and analogues), azoreductase (for azobenzene mustards) and DT-diaphorase (for CB1954); oxidases, such as glucose oxidase (for glucose), xanthine oxidase (for xanthine) and lactoperoxidase; DL- racemases, catalytic antibodies and cyclodextrins.
Preferably, the prodrug is relatively non-toxic compared to the cytotoxic drug. Typically, it has less than 10% of the toxicity, preferably less than 1% of the toxicity as measured in a suitable in vitro cytotoxicity test.
It is likely that the moiety which is able to convert a prodrug to a cytotoxic drug will be active in isolation from the rest of the compound but it is necessary only for it to be active when (a) it is in combination with the rest of the compound and (b) the compound is attached to, adjacent to or internalised in target cells.
When each moiety of the compound is a polypeptide, the two portions may be linked together by any of the conventional ways of cross-linking polypeptides, such as those generally described in O'Sullivan et al (1979) Anal. Biochem.
100, 100-108. For example, the binding moiety may be enriched with thiol groups and the further moiety reacted with a bifunctional agent capable of reacting with those thiol groups, for example the N-hydroxysuccinimide ester of iodoacetic acid (NHIA) or N-succinimidyl-3-(2-pyridyldithio)propionate (SPDP). Amide and thioether bonds, for example achieved with m- maleimidobenzoyl-N-hydroxysuccinimide ester, are generally more stable in vivo than disulphide bonds.
Alternatively, the compound may be produced as a fusion compound by recombinant DNA techniques whereby a length of DNA comprises respective regions encoding the two moieties of the compound of the invention either adjacent one another or separated by a region encoding a linker peptide which does not destroy the desired properties of the compound. Conceivably, the two portions of the compound may overlap wholly or partly.
The invention also provides a kit of parts (or a therapeutic system) comprising (1) a compound of the invention wherein the further moiety which is able to convert a relatively non-toxic prodrug into a cytotoxic drug and (2) a relatively non-toxic prodrug. The kit of parts may comprise any of the compounds of the invention and appropriate prodrugs as herein disclosed.
The invention also provides a kit of parts (or a therapeutic system) comprising (1) a compound of the invention wherein the further moiety is able to bind selectively to a directly or indirectly cytotoxic moiety or to a readily detectable moiety and (2) any one of a directly or indirectly cytotoxic or a readily detectable moiety to which the further moiety of the compound is able to bind.
The cytotoxic moiety may be a radiosensitizer. Radiosensitizers include fluoropyrimidines, thymidine analogues, hydroxyurea, gemcitabine, fludarabine, nicotinamide, halogenated pyrimidines, 3-aminobenzamide, 3- ammobenzodiamide, etanixadole, pimonidazole and misonidazole (see, for example, McGinn et al (1996) J. Natl. Cancer Inst. 88, 1193-11203; Shewach & Lawrence (1996) Invest. New Drugs 14, 257-263; Horsman (1995) Acta Oncol. 34, 571-587; Shenoy & Singh (1992) Clin. Invest. 10, 533-551; Mitchell et al (1989) Int. J. Radiat. Biol. 56, 827-836; Iliakis & Kurtzman (1989) Int. J. Radiat. Oncol. Biol. Phys. 16, 1235-1241; Brown (1989) Int. J. Radiat. Oncol. Biol. Phys. 16, 987-993; Brown (1985) Cancer 55, 2222-2228).
Also, delivery of genes into cells can radiosensitise them, for example delivery of the p53 gene or cyclin D (Lang et al (1998) J. Neurosurg. 89, 125-132; Coco Martin et al (1999) Cancer Res. 59, 1134-1140).
The further moiety may be one which becomes cytotoxic, or releases a cytotoxic moiety, upon irradiation. For example, the boron- 10 isotope, when appropriately irradiated, releases α particles which are cytotoxic (for example, see US 4, 348, 376 to Goldenberg; Primus et al (1996) Bioconjug. Chem. 7, 532-535).
Similarly, the cytotoxic moiety may be one which is useful in photodynamic therapy such as photofrin (see, for example, Dougherty et al (1998) J. Natl. Cancer Inst. 90, 889-905).
The further moiety may comprise a nucleic acid molecule which is directly or indirectly cytotoxic. For example, the nucleic acid molecule may be an antisense oligonucleotide which, upon localisation at the target site is able to enter cells and lead to their death. The oligonucleotide, therefore, may be one which prevents expression of an essential gene, or one which leads to a change in gene expression which causes apoptosis.
Examples of suitable oligonucleotides include those directed at bcl-2 (Ziegler et al (1997) J. Natl. Cancer Inst. 89, 1027-1036), and DNA polymerase α and topoisomerase Ilα (Lee et al (1996) Anticancer Res. 16, 1805-1811.
Peptide nucleic acids may be useful in place of conventional nucleic acids (see Knudsen & Nielsen (1997) Anticancer Drugs 8, 113-118).
In a further embodiment, the binding moiety may be comprised in a delivery vehicle for delivering nucleic acid to the target. The delivery vehicle may be any suitable delivery vehicle. It may, for example, be a liposome containing nucleic acid, or it may be a virus or virus-like particle which is able to deliver nucleic acid. In these cases, the binding moiety is typically present on the surface of the delivery vehicle. For example, the binding moiety, such as a suitable antibody fragment, may be present in the outer surface of a liposome and the nucleic acid to be delivered may be present in the interior of the liposome. As another example, a viral vector, such as a retroviral or adenoviral vector, is engineered so that the binding moiety is attached to or located in the surface of the viral particle thus enabling the viral particle to be targeted to the desired site. Targeted delivery systems are also known such as the modified adenovirus system described in WO 94/10323 wherein, typically, the DNA is
carried within the adenovirus, or adenovirus-like, particle. Michael et al (1995) Gene Therapy 2, 660-668 describes modification of adenovirus to add a cell-selective moiety into a fibre protein. Targeted retroviruses are also available for use in the invention; for example, sequences conferring specific binding affinities may be engineered into pre-existing viral env genes (see Miller & Vile (1995) Faseb J. 9, 190-199 for a review of this and other targeted vectors for gene therapy).
Immunoliposomes (antibody-directed liposomes) may be used in which the binding moiety is an antibody. For the preparation of immuno-liposomes MPB-PE (N-[4-(p-maleimidophenyl)-butyryl]-phosphatidylethanolamine) is synthesised according to the method of Martin & Papahadjopoulos (1982) J. Biol. Chem. 257, 286-288. MPB-PE is incoφorated into the liposomal bilayers to allow a covalent coupling of the antibody, or fragment thereof, to the liposomal surface. The liposome is conveniently loaded with the DNA or other genetic construct for delivery to the target cells, for example, by forming the said liposomes in a solution of the DNA or other genetic construct, followed by sequential extrusion through polycarbonate membrane filters with 0.6 μm and 0.2 μm pore size under nitrogen pressures up to 0.8 MPa. After extrusion, entrapped DNA construct is separated from free DNA construct by ultracentrifugation at 80 000 x g for 45 min. Freshly prepared MPB-PE- liposomes in deoxygenated buffer are mixed with freshly prepared antibody (or fragment thereof) and the coupling reactions are carried out in a nitrogen atmosphere at 4°C under constant end over end rotation overnight. The immunoliposomes are separated from unconjugated antibodies by ultracentrifugation at 80 000 x g for 45 min. Immunoliposomes may be injected intraperitoneally or directly into the tumour.
The nucleic acid delivered to the target site (i.e. MCL cell) may be any suitable DNA which leads, directly or indirectly, to cytotoxicity. For example, the nucleic acid may encode a ribozyme which is cytotoxic to the cell, or it may encode an enzyme which is able to convert a substantially non-toxic prodrug into a cytotoxic drug (this latter system is sometime called GDEPT: Gene Directed Enzyme Prodrug Therapy).
Ribozymes which may be encoded in the nucleic acid to be delivered to the target are described in Cech and Herschlag "Site-specific cleavage of single stranded DNA" US 5,180,818; Altaian et al "Cleavage of targeted RNA by
RNAse P" US 5,168,053, Cantin et al "Ribozyme cleavage of HIV-1 RNA"
US 5,149,796; Cech et al "RNA ribozyme restriction endoribonucleases and methods", US 5,116,742; Been et al "RNA ribozyme polymerases, dephosphorylases, restriction endonucleases and methods", US 5,093,246; and
Been et al "RNA ribozyme polymerases, dephosphorylases, restriction endoribonucleases and methods; cleaves single-stranded RNA at specific site by transesterification", US 4,987,071, all incoφorated herein by reference.
Suitable targets for ribozymes include transcription factors such as c-fos and c- myc, and bcl-2. Durai et al (1997) Anticancer Res. 17, 3307-3312 describes a hammerhead ribozyme against bcl-2.
EP 0 415 731 describes the GDEPT system. Similar considerations concerning the choice of enzyme and prodrug apply to the GDEPT system as to the ADEPT system described above.
The nucleic acid delivered to the target site may encode a directly cytotoxic polypeptide.
Alternatively, the ftirther moiety may comprise a polypeptide or a polynucleotide encoding a polypeptide which is not either directly or indirectly cytotoxic but is of therapeutic benefit. Examples of such polypeptides include anti-proliferative or anti-inflammatory cytokines, and anti-proliferative, immunomodulatory or factors influencing blood clotting which may be of benefit in treating MCL.
The further moiety may usefully be an inhibitor of angiogenesis such as the peptides angiostatin or endostatin. The further moiety may also usefully be an enzyme which converts a precursor polypeptide to angiostatin or endostatin. Human matrix metallo-proteases such as macrophage elastase, gelatinase and stromolysin convert plasminogen to angiostatin (Cornelius et al (1998) J. Immunol. 161, 6845-6852). Plasminogen is a precursor of angiostatin.
In a further embodiment of the invention, the further moiety comprised in the compound of the invention is a readily detectable moiety.
By a "readily detectable moiety" we include the meaning that the moiety is one which, when located at the target site following administration of the compound of the invention into a patient, may be detected, typically non- invasively from outside the body and the site of the target located. Thus, the compounds of this embodiment of the invention are useful in imaging and diagnosis.
Typically, the readily detectable moiety is or comprises a radioactive atom which is useful in imaging. Suitable radioactive atoms include 99mTc and 123I for scintigraphic studies. Other readily detectable moieties include, for example, spin labels for magnetic resonance imaging (MRI) such as I again, 131I, mIn, 19F, 13C, 15N, 170, gadolinium, manganese or iron. Clearly, the compound of the invention must have sufficient of the appropriate atomic isotopes in order for the molecule to be readily detectable.
The radio- or other labels may be incoφorated in the compound of the invention in known ways. For example, if the binding moiety is a polypeptide it may be biosynthesised or may be synthesised by chemical amino acid synthesis using suitable amino acid precursors involving, for example, fluorine-19 in place of hydrogen. Labels such as 99mTc, 123I, 186Rh, 188Rh and πιIn can, for example, be attached via cysteine residues in the binding moiety. Yttrium-90 can be attached via a lysine residue. The IODOGEN method (Fraker et al (1978) Biochem. Biophys. Res. Comm. 80, 49-57) can be used to
1 3 incoφorate I. Reference ("Monoclonal Antibodies in Immunoscintigraphy",
J-F Chatal, CRC Press, 1989) describes other methods in detail.
In a further preferred embodiment of the invention the further moiety is able to bind selectively to a directly or indirectly cytotoxic moiety or to a readily detectable moiety. Thus, in this embodiment, the further moiety may be any moiety which binds to a ftirther compound or component which is cytotoxic or readily detectable.
The further moiety may, therefore be an antibody which selectively binds to the further compound or component, or it may be some other binding moiety such as streptavidin or biotin or the like. The following examples illustrate the types of molecules that are included in the invention; other such molecules are readily apparent from the teachings herein.
A bispecific antibody wherein one binding site comprises the binding moiety (which selectively binds to a protein listed in Table 1) and the second binding site comprises a moiety which binds to, for example, an enzyme which is able to convert a substantially non-toxic prodrug to a cytotoxic drug.
Alternatively, the compound may comprise an antibody which selectively binds to a protein listed in Table 1, to which is bound biotin. Avidin or streptavidin which has been labelled with a readily detectable label may be used in conjunction with the biotin labelled antibody in a two-phase imaging system wherein the biotin labelled antibody is first localised to the target site in the patient, and then the labelled avidin or streptavidin is administered to the patient. Bispecific antibodies and biotin/streptavidin (avidin) systems are reviewed by Rosebrough (1996) Q J Nucl. Med. 40, 234-251.
In a preferred embodiment of the invention, the binding moiety and the further moiety are polypeptides which are fused.
The compounds of the first of the invention are useful in treating, imaging or diagnosing MCL, as described in more detail below.
A sixth aspect of the invention provides a pharmaceutical composition comprising a compound according to the invention and a pharmaceutically acceptable carrier.
By "pharmaceutically acceptable" is included that the formulation is sterile and pyrogen free. Suitable pharmaceutical carriers are well known in the art of pharmacy.
The carrier(s) must be "acceptable" in the sense of being compatible with the compound of the invention and not deleterious to the recipients thereof. Typically, the carriers will be water or saline which will be sterile and pyrogen free; however, other acceptable carriers may be used.
Typically the pharmaceutical compositions or formulations of the invention are for parenteral administration, more particularly for intravenous administration.
Formulations suitable for parenteral administration include aqueous and nonaqueous sterile injection solutions which may contain anti-oxidants, buffers, bacteriostats and solutes which render the formulation isotonic with the blood of the intended recipient; and aqueous and non-aqueous sterile suspensions which may include suspending agents and thickening agents.
A seventh aspect of the invention provides a method of imaging MCL cells in the body of an individual, the method comprising administering to the individual an effective amount of a compound according to the first aspect of the invention wherein the ftirther moiety is a readily detectable moiety.
In a preferred embodiment of this aspect of the invention, the method comprises the further step of detecting the location of the compound in the individual.
Detecting the compound or antibody can be achieved using methods well known in the art of clinical imaging and diagnostics. The specific method required will depend on the type of detectable label attached to the compound or antibody. For example, radioactive atoms may be detected using autoradiography or in some cases by magnetic resonance imaging (MRI) as described above.
A eighth aspect of the invention provides a method of diagnosing or prognosing MCL in an individual, the method comprising administering to the individual an effective amount of a compound according to the first aspect of the invention wherein the further moiety is a readily detectable moiety.
The method may be one which is an aid to diagnosis.
In a preferred embodiment of this aspect of the invention, the method of diagnosing, or aiding diagnosis of, MCL in an individual comprises the further step of detecting the location of the compound in the individual.
An ninth aspect of the invention provides a method of treating an individual in need of treatment, the method comprising administering to the individual an effective amount of a compound according to the first aspect of the invention
wherein the further moiety is a cytotoxic or therapeutic moiety. Preferably, the patient in need of treatment has MCL.
It will be appreciated compound of the invention may act directly on MCL cells by binding selectively to a protein or polypeptide listed in Table 1.
Alternatively, the compound may act indirectly by interfering with (e.g. inhibiting or preventing) the interaction between a protein or polypeptide listed in Table 1 and a second moiety, wherein the interaction is essential for growth of MCL cells. For example, the compound may bind to a site on the protein or polypeptide listed in Table 1 which interacts with the further moiety, or vice versa, thereby interfering with the interaction between the protein or polypeptide and the further moiety. Alternatively, the compound may act via an allosteric mechanism to interfere with the interaction between the protein or polypeptide and the further moiety.
Preferably, the compound interferes with the interaction between cellular growth factors or cell surface receptor thus affecting proliferation, differentiation or maturation of the cancer cell, e.g. as has been shown for the IL-13/IL-13 receptor interactions. The therapeutic efficacy is thus achieved by interfering with normal cellular functions that are specifically over-expressed in the malignant cell, giving that particular cell a specific signal.
It will be further appreciated that, depending on the particular compound used in imaging, diagnosis or treatment, the timing of administration may vary and the number of other components used in therapeutic systems disclosed herein may vary.
For example, in the case where the compound of the invention comprises a readily detectable moiety or a directly cytotoxic moiety, it may be that only the compound, in a suitable formulation, is administered to the patient. Of course, other agents such as immunosuppressive agents and the like may be administered.
In respect of compounds which are detectably labelled, imaging takes place once the compound has localised at the target site.
However, if the compound is one which requires a further component in order to be useful for treatment, imaging or diagnosis, the compound of the invention may be administered . and allowed to localise at the target site, and then the further component administered at a suitable time thereafter.
For example, in respect of the ADEPT and ADEPT-like systems above, the binding moiety-enzyme moiety compound is administered and localises to the target site. Once this is done, the prodrug is administered.
Similarly, for example, in respect of the compounds wherein the further moiety comprised in the compound is one which binds a ftirther component, the compound may be administered first and allowed to localise at the target site, and subsequently the further component is administered.
Thus, in one embodiment a biotin-labelled antibody is administered to the patient and, after a suitable period of time, detectably labelled streptavidin is
administered. Once the streptavidin has localised to the sites where the antibody has localised (i.e. the target sites) imaging takes place.
A tenth aspect of the invention provides a method of introducing genetic material selectively into MCL cells the method comprising contacting the cells with a compound according to the first aspect of the invention as described above wherein the further moiety is a nucleic acid, or a compound comprising (i) a binding moiety which selectively binds to a protein listed in Table 1 and (ii) a nucleic acid.
Preferably, the binding moiety is an antibody. Typically, the binding moiety is comprised in a delivery vehicle and preferably, the delivery vehicle is a liposome, as described in further detail above. In this embodiment, the further moiety is nucleic acid and is comprised within the liposome, also as described above. Typically, the method is used in gene therapy, and the genetic material is therapeutically useful. Therapeutically useful genetic material includes that which encodes a therapeutic protein.
A eleventh aspect of the invention provides a nucleic acid molecule encoding a compound according to the first aspect of the invention or a binding moiety thereof. By "nucleic acid molecule" we include DNA, cDNA and mRNA molecules, which may be single- or double-stranded.
An twelfth aspect of the invention provides an expression vector comprising a nucleic acid molecule according to the tenth aspect of the invention. By "expression vector" we mean one which is capable, in an appropriate host, of expressing a polypeptide encoded by the nucleic acid molecule.
Such vectors may be useful in expressing the encoded compound or binding moiety thereof in a host cell for production of useful quantities of the compounds of the invention.
A variety of methods have been developed to operably link nucleic acid molecules, especially DNA, to vectors, for example, via complementary cohesive termini. For instance, complementary homopolymer tracts can be added to the DNA segment to be inserted into the vector DNA. The vector and DNA segment are then joined by hydrogen bonding between the complementary homopolymeric tails to form recombinant DNA molecules.
Synthetic linkers containing one or more restriction sites provide an alternative method of joining the DNA segment to vectors. The DNA segment, e.g. generated by endonuclease restriction digestion, is treated with bacteriophage T4 DNA polymerase or E.coli DNA polymerase I, enzymes that remove protruding, 3 '-single-stranded termini with their 3'-5'-exonucleolytic activities, and fill in recessed 3 '-ends with their polymerising activities.
The combination of these activities therefore generates blunt-ended DNA segments. The blunt-ended segments are then incubated with a larger molar excess of linker molecules in the presence of an enzyme that is able to catalyse the ligation of blunt-ended DNA molecules, such as bacteriophage T4 DNA ligase. Thus, the products of the reaction are DNA segments carrying polymeric linker sequences at their ends. These DNA segments are then cleaved with the appropriate restriction enzyme and ligated to an expression
vector that has been cleaved with an enzyme that produces termini compatible with those of the DNA segment.
Synthetic linkers containing a variety of restriction endonuclease site are commercially available from a number of sources including International Biotechnologies Inc., New Haven, CN, USA.
A desirable way to modify the DNA encoding the polypeptide of the invention is to use PCR. This method may be used for introducing the DNA into a suitable vector, for example by engineering in suitable restriction sites, or it may be used to modify the DNA in other useful ways as is known in the art.
In this method the DNA to be enzymatically amplified is flanked by two specific primers which themselves become incoφorated into the amplified DNA. The said specific primers may contain restriction endonuclease recognition sites which can be used for cloning into expression vectors using methods known in the art.
The DNA (or in the case of retroviral vectors, RNA) is then expressed in a suitable host to produce a polypeptide comprising the compound of the invention or binding moiety thereof. Thus, the DNA encoding the polypeptide may be used in accordance with known techniques, appropriately modified in view of the teachings contained herein, to construct an expression vector, which is then used to transform an appropriate host cell for the expression and production of the compound of the invention or binding moiety thereof. Such techniques include those disclosed in US Patent Nos. 4,440,859 issued 3 April 1984 to Rutter et al, 4,530,901 issued 23 July 1985 to Weissman, 4,582,800
issued 15 April 1986 to Crowl, 4,677,063 issued 30 June 1987 to Mark et al, 4,678,751 issued 7 July 1987 to Goeddel, 4,704,362 issued 3 November 1987 to Itakura et al, 4,710,463 issued 1 December 1987 to Murray, 4,757,006 issued 12 July 1988 to Toole, Jr. et al, 4,766,075 issued 23 August 1988 to Goeddel et al and 4,810,648 issued 7 March 1989 to Stalker, all of which are incoφorated herein by reference.
The DNA (or in the case or retroviral vectors, RNA) encoding the polypeptide constituting the compound of the invention or binding moiety thereof may be joined to a wide variety of other DNA sequences for introduction into an appropriate host. The companion DNA will depend upon the nature of the host, the manner of the introduction of the DNA into the host, and whether episomal maintenance or integration is desired.
Generally, the DNA is inserted into an expression vector, such as a plasmid, in proper orientation and correct reading frame for expression. If necessary, the DNA may be linked to the appropriate transcriptional and translational regulatory control nucleotide sequences recognised by the desired host, although such controls are generally available in the expression vector. The vector is then introduced into the host through standard techniques. Generally, not all of the hosts will be transformed by the vector. Therefore, it will be necessary to select for transformed host cells. One selection technique involves incoφorating into the expression vector a DNA sequence, with any necessary control elements, that codes for a selectable trait in the transformed cell, such as antibiotic resistance. Alternatively, the gene for such selectable trait can be on another vector, which is used to co-transform the desired host cell.
Host cells that have been transformed by the expression vector of the invention are then cultured for a sufficient time and under appropriate conditions known to those skilled in the art in view of the teachings disclosed herein to permit the expression of the polypeptide, which can then be recovered.
Many expression systems are known, including bacteria (for example, E.coli and Bacillus subtilis), yeasts (for example Saccharomyces cerevisiae), filamentous fungi (for example Aspergillus), plant cells, animal cells and insect cells.
The vectors typically include a prokaryotic replicon, such as the ColEl ori, for propagation in a prokaryote, even if the vector is to be used for expression in other, non-prokaryotic, cell types. The vectors can also include an appropriate promoter such as a prokaryotic promoter capable of directing the expression (transcription and translation) of the genes in a bacterial host cell, such as E.coli, transformed therewith.
A promoter is an expression control element formed by a DNA sequence that permits binding of RNA polymerase and transcription to occur. Promoter sequences compatible with exemplary bacterial hosts are typically provided in plasmid vectors containing convenient restriction sites for insertion of a DNA segment of the present invention.
Typical prokaryotic vector plasmids are pUC18, pUC19, pBR322 and pBR329 available from Biorad Laboratories, (Richmond, CA, USA) and pTrc99A and pKK223-3 available from Pharmacia, Piscataway, NJ, USA.
A typical mammalian cell vector plasmid is pSVL available from Pharmacia, Piscataway, NJ, USA. This vector uses the SV40 late promoter to drive expression of cloned genes, the highest level of expression being found in T antigen-producing cells, such as COS-1 cells.
An example of an inducible mammalian expression vector is pMSG, also available from Pharmacia. This vector uses the glucocorticoid-inducible promoter of the mouse mammary tumour virus long terminal repeat to drive expression of the cloned gene.
Useful yeast plasmid vectors are pRS403-406 and pRS413-416 and are generally available from Stratagene Cloning Systems, La Jolla, CA 92037, USA. Plasmids pRS403, pRS404, pRS405 and pRS406 are Yeast Integrating plasmids (Yips) and incoφorate the yeast selectable markers HIS3, TRP1, LEU2 and URA3. Plasmids pRS413-416 are Yeast Centromere plasmids (Ycps).
Other vectors and expression systems are well known in the art for use with a variety of host cells.
An thirteenth aspect of the invention provides a recombinant host cell comprising a nucleic acid molecule or vector of the present invention.
The host cell can be either prokaryotic or eukaryotic. Bacterial cells are preferred prokaryotic host cells and typically are a strain oi E.coli such as, for example, the E.coli strains DH5 available from Bethesda Research Laboratories Inc., Bethesda, MD, USA, and RR1 available from the American Type Culture Collection (ATCC) of Rockvilie, MD, USA (No. ATCC 31343). Preferred eukaryotic host cells include yeast, insect and mammalian cells, preferably vertebrate cells such as those from a mouse, rat, monkey or human fϊbroblastic and kidney cell lines. Yeast host cells include YPH499, YPH500 and YPH501 which are generally available from Stratagene Cloning Systems, La Jolla, CA 92037, USA. Preferred mammalian host cells include Chinese hamster ovary (CHO) cells available from the ATCC as CRL 1658 and 293 cells which are human embryonic kidney cells. Preferred insect cells are Sf9 cells which can be transfected with baculovirus expression vectors.
Transformation of appropriate cell hosts with a DNA construct of the present invention is accomplished by well known methods that typically depend on the type of vector used. With regard to transformation of prokaryotic host cells, see, for example, Cohen et al (1972) Proc. Natl. Acad. Sci. USA 69, 2110 and Sambrook et al (1989) Molecular Cloning, A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY. Transformation of yeast cells is described in Sherman et al (1986) Methods In Yeast Genetics, A Laboratory Manual, Cold Spring Harbor, NY. The method of Beggs (1978) Nature 275, 104-109 is also useful. With regard to vertebrate cells, reagents useful in transfecting such cells, for example calcium phosphate and DEAE-dextran or liposome formulations, are available from Stratagene Cloning Systems, or Life Technologies Inc., Gaithersburg, MD 20877, USA.
Electroporation is also useful for transforming and/or transfecting cells and is well known in the art for transforming yeast cells, bacterial cells, insect cells and vertebrate cells.
For example, many bacterial species may be transformed by the methods described in Luchansky et al (1988) Mol. Microbiol. 2, 637-646 incoφorated herein by reference. The greatest number of transformants is consistently recovered following electroporation of the DNA-cell mixture suspended in 2.5 PEB using 6250V per cm at 25 μFD.
Methods for transformation of yeast by electroporation are disclosed in Becker & Guarente (1990) Methods Enzymol. 194, 182.
Successfully transformed cells, i.e. cells that contain a DNA construct of the present invention, can be identified by well-known techniques. For example, cells resulting from the introduction of an expression construct of the present invention can be grown to produce the polypeptide of the invention. Cells can be harvested and lysed and their DNA content examined for the presence of the DNA using a method such as that described by Southern (1975) J. Mol. Biol. 98, 503 or Berent et al (1985) Biotech. 3, 208. Alternatively, the presence of the protein in the supernatant can be detected using antibodies as described below.
In addition to directly assaying for the presence of recombinant DNA, successful transformation can be confirmed by well known immunological methods when the recombinant DNA is capable of directing the expression of
the protein. For example, cells successfully transformed with an expression vector produce proteins displaying appropriate antigenicity.
Samples of cells suspected of being transformed are harvested and assayed for the protein using suitable antibodies.
The host cell may be a host cell within an non-human animal body. Thus, transgenic non-human animals which express a compound according to the first aspect of the invention (or a binding moiety thereof) by virtue of the presence of the transgene are included. Preferably, the transgenic non-human animal is a rodent such as a mouse. Transgenic non-human animals can be made using methods well known in the art.
A fourteenth aspect of the invention provides a method of producing a compound of the invention or binding moiety thereof, the method comprising expressing a nucleic acid molecule according to the tenth aspect of the invention or culturing a host cell according to the twelfth aspect of the invention.
Methods of cultivating host cells and isolating recombinant proteins are well known in the art. It will be appreciated that, depending on the host cell, the compounds of the invention (or binding moieties thereof) produced may differ. For example, certain host cells, such as yeast or bacterial cells, either do not have, or have different, post-translational modification systems which may result in the production of forms of compounds of the invention (or binding moieties thereof) which may be post-translationally modified in a different way.
It is preferred that compounds of the invention (or binding moieties thereof) are produced in a eukaryotic system, such as a mammalian cell.
According to a less preferred embodiment, the compounds of the invention (or binding moieties thereof) can be produced in vitro using a commercially available in vitro translation system, such as rabbit reticulocyte lysate or wheatgerm lysate (available from Promega). Preferably, the translation system is rabbit reticulocyte lysate. Conveniently, the translation system may be coupled to a transcription system, such as the TNT transcription-translation system (Promega). This system has the advantage of producing suitable mRNA transcript from an encoding DNA polynucleotide in the same reaction as the translation.
Preferably, the production method of this aspect of the invention comprises a further step of isolating the compounds of the invention (or binding moieties thereof) produced from the host cell or from the in vitro translation mix. Preferably, the isolation employs an antibody which selectively binds the expressed polypeptide of the invention.
As discussed above, in a preferred embodiment of the compounds of the first aspect of the invention the binding moiety comprises an antibody or antigen- binding fragment thereof
Antibodies can be raised in an animal by immunising with an appropriate peptide. Appropriate peptides include the proteins listed in Table 1 and fragments thereof. Alternatively, with today's technology, it is possible to
make antibodies as defined herein without the need to use animals. Such techniques include, for example, antibody phage display technology as is well known in the art. Appropriate peptides, as described herein, may be used to select antibodies produced in this way.
It will be appreciated that, with the advancements in antibody technology, it may not be necessary to immunise an animal in order to produce an antibody. Synthetic systems, such as phage display libraries, may be used. The use of such systems is included in the methods of the invention and the products of such systems are "antibodies" for the purposes of the invention.
It will be appreciated that such antibodies which recognise one of the proteins listed in Table 1 and variants or fragments thereof are useful research reagents and therapeutic agents, particularly when prepared as a compound of the invention as described above. Suitably, the antibodies of the invention are detectably labelled, for example they may be labelled in such a way that they may be directly or indirectly detected. Conveniently, the antibodies are labelled with a radioactive moiety or a coloured moiety or a fluorescent moiety, or they may be linked to an enzyme. Typically, the enzyme is one which can convert a non-coloured (or non-fluorescent) substrate to a coloured (or fluorescent) product. The antibody may be labelled by biotin (or streptavidin) and then detected indirectly using streptavidin (or biotin) which has been labelled with a radioactive moiety or a coloured moiety or a fluorescent moiety, or the like or they may be linked to any enzyme of the type described above.
A fifteenth aspect of the invention provides a method of identifying cells associated with MCL, the method comprising analysing the pattern of gene expression in a sample of cells to be tested and comparing it to the pattern of gene expression in a sample of known MCL cells.
Preferably, the known MCL cells are characterised by the upregulation of expression of one or more genes encoding a protein listed in Table 1 compared to normal B-cells.
In a preferred embodiment of the fourteenth aspect of the invention, the method further comprises comparing the pattern of gene expression in a sample of cells to be tested with the pattern of gene expression in a control sample.
Conveniently, the control sample comprises normal B-cells.
Advantageously, the cells to be tested are identified as MCL cells if the expression of one or more genes encoding a protein listed in Table 1 is upregulated compared to normal B-cells.
Preferably, the cells to be tested are identified as MCL cells if the expression of genes encoding all of the proteins listed in Table 1 is upregulated compared to normal B-cells.
By "upregulated" we mean that the expression of the gene is increased by at least 10% compared to expression of the same gene in normal B-cells.
Preferably, expression of the gene is increased by at least 20%, 30%, 40% or 50%. Most preferably expression of the gene is increased by at least 50%.
A further aspect of the invention provides a method of distinguishing between different types or stages of MCL, the method comprising analysing the pattern of gene expression in a sample of cells to be tested and comparing it to the pattern of gene expression in a sample of MCL cells of a known type or stage.
Preferably, the known MCL cells are characterised by the upregulation of expression of one or more genes encoding a protein listed in Table 1 compared to normal B-cells.
A further aspect of the invention is a method of screening for a molecule with efficacy in the treatment of MCL, the method comprising the steps of:
(i) contacting a molecule to be tested with a protein listed in Table 1 (or a fragment thereof); and
(ii) detecting the presence of a complex containing the protein (or fragment thereof) and the molecule to be tested.
In a preferred embodiment, the test molecule is a polypeptide.
Suitable peptide ligands that will bind to a protein listed in Table 1 (or a fragment thereof) may be identified using methods known in the art.
One method, disclosed by Scott and Smith (1990) Science 249, 386-390 and Cwirla et al (1990) Proc. Natl. Acad. Sci. USA 87, 6378-6382, involves the screening of a vast library of filamentous bacteriophages, such as Ml 3 or fd, each member of the library having a different peptide fused to a protein on the surface of the bacteriophage. Those members of the library that bind to a protein listed in Table 1 (or a fragment thereof) are selected using an iterative binding protocol, and once the phages that bind most tightly have been purified, the sequence of the peptide ligands may be determined simply by sequencing the DNA encoding the surface protein fusion. Another method that can be used is the NovaTope (TM) system commercially available from Novagen, Inc., 597 Science Drive, Madison, WT 53711. The method is based on the creation of a library of bacterial clones, each of which stably expresses a small peptide derived from a candidate protein in which the ligand is believed to reside. The library is screened by standard lift methods using the antibody or other binding agent as a probe. Positive clones can be analysed directly by DNA sequencing to determine the precise amino acid sequence of the ligand.
Further methods using libraries of beads conjugated to individual species of peptides as disclosed by Lam et al (1991) Nature 354, 82-84 or synthetic peptide combinatorial libraries as disclosed by Houghten et al (1991) Nature 354, 84-86 or matrices of individual synthetic peptide sequences on a solid support as disclosed by Pirrung et al in US 5143854 may also be used to identify peptide ligands.
It will be appreciated that screening assays which are capable of high throughput operation will be particularly preferred. Examples may include cell based assays and protein-protein binding assays. An SPA-based (Scintillation
Proximity Assay; Amersham International) system may be used. For example, an assay for identifying a compound capable of modulating the activity of a protein kinase may be performed as follows. Beads comprising scintillant and a polypeptide that may be phosphorylated may be prepared. The beads may be mixed with a sample comprising the protein kinase and P-ATP or P-ATP and with the test compound. Conveniently this is done in a 96-well format. The plate is then counted using a suitable scintillation counter, using known parameters for P or P SPA assays. Only P or P that is in proximity to the scintillant, i.e. only that bound to the polypeptide, is detected. Variants of such an assay, for example in which the polypeptide is immobilised on the scintillant beads via binding to an antibody, may also be used.
Other methods of detecting polypeptide/polypeptide interactions include ultrafiltration with ion spray mass spectroscopy/HPLC methods or other physical and analytical methods. Fluorescence Energy Resonance Transfer (FRET) methods, for example, well known to those skilled in the art, may be used, in which binding of two fluorescent labelled entities may be measured by measuring the interaction of the fluorescent labels when in close proximity to each other.
Alternative methods of detecting binding of a polypeptide to macromolecules, for example DNA, RNA, proteins and phospholipids, include a surface plasmon resonance assay, for example as described in Plant et al (1995) Analyt Biochem 226(2), 342-348. Methods may make use of a polypeptide that is labelled, for example with a radioactive or fluorescent label.
A further method of identifying a compound that is capable of binding to a protein listed in Table 1 (or a fragment thereof) is one where the polypeptide is exposed to the compound and any binding of the compound to the said polypeptide is detected and/or measured. The binding constant for the binding of the compound to the polypeptide may be determined. Suitable methods for detecting and/or measuring (quantifying) the binding of a compound to a polypeptide are well known to those skilled in the art and may be performed, for example, using a method capable of high throughput operation, for example a chip-based method. New technology, called VLSIPS™, has enabled the production of extremely small chips that contain hundreds of thousands or more of different molecular probes. These biological chips or arrays have probes arranged in arrays, each probe assigned a specific location. Biological chips have been produced in which each location has a scale of, for example, ten microns. The chips can be used to determine whether target molecules interact with any of the probes on the chip. After exposing the array to target molecules under selected test conditions, scanning devices can examine each location in the array and determine whether a target molecule has interacted with the probe at that location.
Biological chips or arrays are useful in a variety of screening techniques for obtaining information about either the probes or the target molecules. For example, a library of peptides can be used as probes to screen for drugs. The peptides can be exposed to a receptor, and those probes that bind to the receptor can be identified. See US Patent No. 5,874,219 issued 23 February 1999 to Rava et α/.
It will be understood that it will be desirable to identify compounds that may modulate the activity of the a protein listed in Table 1 in vivo. Thus it will be understood that reagents and conditions used in the method may be chosen such that the interactions between the said and the interacting polypeptide are substantially the same as between a said naturally occurring polypeptide and a naturally occurring interacting polypeptide in vivo.
It will be appreciated that in the method described herein, the ligand may be a drug-like compound or lead compound for the development of a drug-like compound.
The term "drug-like compound" is well known to those skilled in the art, and may include the meaning of a compound that has characteristics that may make it suitable for use in medicine, for example as the active ingredient in a medicament. Thus, for example, a drug-like compound may be a molecule that may be synthesised by the techniques of organic chemistry, less preferably by techniques of molecular biology or biochemistry, and is preferably a small molecule, which may be of less than 5000 daltons and which may be water- soluble. A drug-like compound may additionally exhibit features of selective interaction with a particular protein or proteins and be bioavailable and/or able to penetrate target cellular membranes, but it will be appreciated that these features are not essential.
The term "lead compound" is similarly well known to those skilled in the art, and may include the meaning that the compound, whilst not itself suitable for use as a drug (for example because it is only weakly potent against its intended target, non-selective in its action, unstable, poorly soluble, difficult to
synthesise or has poor bioavailability) may provide a starting-point for the design of other compounds that may have more desirable characteristics.
Alternatively, the methods may be used as "library screening" methods, a term well known to those skilled in the art. Thus, for example, the method of the invention may be used to detect (and optionally identify) a polynucleotide capable of expressing a polypeptide activator of a protein listed in Table 1. Aliquots of an expression library in a suitable vector may be tested for the ability to give the required result.
Preferably, the compound decreases the activity of the protein listed in Table 1. For example, the compound may bind substantially reversibly or substantially irreversibly to the active site of said protein. In a ftirther example, the compound may bind to a portion of said protein that is not the active site so as to interfere with the binding of the said protein to its ligand. In a still further example, the compound may bind to a portion of said protein so as to decrease said protein's activity by an allosteric effect. This allosteric effect may be an allosteric effect that is involved in the natural regulation of the said protein's activity, for example in the activation of the said protein by an "upstream activator".
EXAMPLES
Example 1
Materials and methods
MCL samples
Fresh MCL tumour material (2 samples, designated MCLs6 and MCLs7) was cut into small pieces and suspended in RPMI 1640 (Life Technologies, Gaithersburg, MD) containing 10% Fetal Bovine serum (HyClone Laboratories, Inc., Logan, Utah) (R10). The cells were filtrated through a cell strainer (Falcon) to remove any remaining tissue debris. The lymphocytes were purified using Ficoll-Isopaque (Amersham Pharmacia Biotech, Uppsala, Sweden) and the T-cells were then depleted using CD3 Dynabeads (Dynal A.S, Oslo, Norway) leaving CD5+/CD19+ tumour cells with 95% purity (analysed by FACS, data not shown). The cells were then pelleted and lysed in Trizol (Life Technologies, Gaithersburg, MD).
Frozen tumour samples (5 samples) were homogenised (2 x 15 sec) directly into Trizol using an Ultra Turrax knife homogenizer (IKA-WERK, Tamro Med Lab, Mδlndal, Sweden).
Normal B-cell populations
The normal B-cell populations were derived from fresh tonsils and sorted out on a FACSAdvantageSE™ (BD Immunocytometry Systems, San Jose, CA). The cells were put into suspension in R10 and the lymphocytes were purified
using Ficoll-Isopaque (Amersham Pharmacia Biotech, Uppsala, Sweden). The different B-cell populations were sorted out to a purity of >95% (data not shown) by staining for different surface antigens (Pascual et al., 1997, Baillieres Clin Haematol 10:525-538). The naϊve B-cells were sorted out as IgD , CD23" cells from two different donors (donor nos. 3 and 4). The B-cells that encountered antigen were sorted out as IgD , CD23 cells from three different donors (donor nos. 2, 3 and 4). The centroblast were sorted out as IgD", CD38+ and CD77" cells from two different donors (donor nos. 1 and 2). The centrocytes were sorted out as IgD", CD38 and CD77 cells from two different donors (donor nos. 1 and 4). The memory B-cells were sorted out as CD38", IgD" cells from two different donors (donor nos. 1 and 2). The sorted cell populations were lysed in Trizol.
Isolation of mRNA
Cultured cells and freshly isolated cells were lysed in Trizol. The RNA was extracted from the cell lysate by adding 0.2 volumes of chloroform. The aqueous phase containing the RNA was separated and subsequently precipitated with isopropanol and washed in 75% ethanol. The RNA pellet was dissolved in DEPC-H20 and further purified with the RNeasy Mini Kit (QIAGEN GmbH, Hilden, Germany). The total RNA content was assessed by spectroscopy at Abs 260/280 nm (GeneQuant II, Pharmacia Biotech Uppsala, Sweden). After a second precipitation step in 2.5 volumes of ethanol and subsequent wash, the RNA was resuspended in DEPC-H20.
A minimum of 5 μg total RNA from the preparations was used for the cDNA synthesis. The cDNA synthesis was performed according to the protocol supplied by Affymetrix, Inc. (Santa Clara, CA, USA) using the Superscript Choise System (Gibco BRL, Life Technologies, Taby, Sweden, Paisley, UK). In order to monitor the reaction, a mixture of in vitro transcribed bacterial cRNAs (lysX, pheX, thrX and frpnX; ATCC, Manassas, VA, USA) was added to the reaction mixture. The first-strand cDNA synthesis was performed at 42°C for 2 hr using a final concentration of lx "first-strand sythesis" buffer, lOOpmol T7-(dT)24primer, lOmM DTT, 500μM dNTPs, 200 U Superscript II reverse transcriptase (per μg RNA). The second-strand synthesis was performed at 16°C for 2 hr using a final concentration of lx "second-strand synthesis" buffer, 200 μM dNTP, 10 U DNA ligase, 40 U DNA Polymerase I and 2 U RnaseH. 2 U T4 DNA polymerase was added to the reaction for 5 min at the end of the incubation. The double stranded cDNA was extracted with 25:24:1 phenol:chloroform:isoamyl alcohol at pH 8.0 and subsequent precipitation in 0.5 vol of 7.5 M NH4OAc, 2.5 vol 99.7% ethanol and 20μg/ml glycogen with an immediate wash in 80% ethanol. The cDNA product was in vitro transcribed using the Enzo BioArray HighYield RNA Transcript Labeling Kit (Enzo Diagnostics, NY, USA). Biotinylated CTP and UTP are incoφorated into the transcription cRNA product by a T7 RNA polymerase. The reaction was performed at 37°C for 4-5 h according to the protocol supplied with the kit. The amplified cRNA was purified with the RNeasy Mini Kit (QIAGEN GmbH, Hilden, Germany) and eluted in RNase-free water.
A quality assessment of the product was performed by spectroscopy at Abs 260/280 nm. The cRNA was fragmented in 40 mM Tris-acetate, pH 8.1, 100 mM KOAc, 30 mM MgOAc at 94°C for 35 min.
Hybridization and Scanning
A hybridization cocktail was prepared with the biotinylated and fragmented cRNA at 50 μg/ml, 50pM control oligonucleotide B2: Biotin-5'- GTCGTCAAGATGCTACCGTTCAGGA] [SEQ ID NO. 112], 0.1 mg/ml herring sperm DNA, 0.5 mg/ml acetylated BSA, 100 mM MES, 20 mM EDTA, 0.01% Tween 20 and bacterial cRNA controls: BioB, BioC, BioD and ere at 1.5, 5.0, 25, and 100 pM respectively. Prior to hybridization, the hybridization cocktail was heated to 99°C for 5 min and to 45°C for 5 min and briefly spun. The pre-wet Gene Chip probe array cartridge (U95 Array, Affymetrix, Santa Clara, CA, USA) was filled with the hybridization cocktail and incubated on rotation, 60 φm at 45 °C for 16-18h. The cartridge was then subjected to an automated washing procedure using the Gene Chip Fluidics Station 400 and software (Affymetrix, Santa Clara, CA, USA): 10 cycles at 25°C with non-stringent wash buffer containing 6x SSPE, 0.01% Tween-20, 0.005% Antifoam and then a subsequent 10 cycles with stringent wash buffer containing 100 mM NaMES and 0.01% Tween-20. The probe array was then stained for 10 min at 25°C with a solution of 2 mg/ml acetylated BSA, lOμg/ml Streptavidin R-Phycoerytrin (Molecular Probes, Eugene, OR, USA) in Stain Buffer containing 100 mM NaMES and 0.05% Tween-20 and 0.005% Antifoam followed by 10 cycles at 25°C with non-stringent wash buffer, secondary stain for 10 min at 25°C was performed with a solution of 2 mg/ml
acetylated BSA, 0.1 mg/ml normal goat IgG (Sigma Chemical, St. Louis, Missouri, USA) and 3 μg/ml biotinylated goat anti-streptavidin antibody (Vector Laboratories, Burlingame, CA, USA) in Stain Buffer. A third staining step with Streptavidin R-Phycoerytrin was performed as above prior to a final 15 cycles with non-stringent wash buffer at 30°C. The probe arrays were scanned with the Gene Array Scanner (Affymetrix Inc., Santa Clara, CA, USA) controlled by the Micro Array Suite 4.0 (Affymetrix Inc., Santa Clara, CA, USA).
Oligonucleotide Array
Experiments were performed using a human U95 chip containing 12700 genes and EST (Affymetrix, Santa Clara, CA, USA)
Statistical and Database Methods
The Average Differences were scaled in Microarray Suite (Affymetrix) against a target value of 500 enabling different arrays to be compared. The Average Difference values were then imported into Gene Spring (Silicon Genetics) for further data analysis, including creation of experiment trees, where the minimum distance was set to 0,001 and the separation ratio to 0,95.
Results
MCLs (n=7) and normal B-cell populations (naϊve B-cells( n=2), B-cells that encountered antigen (n=3), Centroblasts (n=2), Centrocytes (n=2) and memory cells (n=2)) were studied. There are 12700 probe sets on the U95 array and
between 43% to 50% were designated as Present (according to the Affymetrix Absolute call algorithm) in the different experiments.
The MCLs were compared to the pre GC B-cells (naive B-cells and B-cells that encountered antigen) as one group to find genes that differed between the malignant and normal counteφart (Pascual et al., 1997, Baillieres Clin Haematol 10:525-538). The neoplasms were also compared to all of the B-cell populations as one group (na'ϊve B-cells, B-cells that encountered antigen, centroblasts, centrocytes and memory B-cells) to find genes with a MCL specific expression.
The criteria for designating a gene as up-regulated or down-regulated in the two different groups were that the gene should have an expression in 6 out of 7 MCLs that differed no less than 2 fold from all of the mean values of the replicates off that group (the pre-GC B-cells or all B-cell populations). This excludes all the genes that are only detected in the non-purified samples (1-5) and that could be expressed in other cells than the MCL cells.
Results identified sixty-four (64) genes encoding cell surface and/or soluble polypeptides as being upregulated in MCL, as listed in Table 1.
Example 2 - Sp-53 cell line andIL-10 receptor upregulation
This example shows a functional relation between a differentially up-regulated gene/gene product and the proliferation of a cancer cell line of mantle cell origin.
The mantle cell lymphoma cell line Sp-53 proliferates continuously in vitro. The effects of a variety of lymphokines were tested by adding varying concentrations of these molecules to the Sp-53 cell line. Cell proliferation was monitored, since tumour cell growth is a relevant parameter in relation to the use of antibodies in therapy of human mantle cell lymphomas.
Cell proliferation was monitored by measuring the amount of DNA synthesis as indicated by the incoφoration of radioactive labelled thymidine, a standard procedure that the skilled person would consider as common general knowledge. The following steps were undertaken in order to carry out this study.
1. 50,000 Sp53 mantle cell lymphoma cells were seeded in each well of a microtiter plate.
2. 20 ng/ml of lymphokine was added (e.g. Interleukin 10 (IL-10) )
3. The cells were cultured for 4 hours and 0.5 μCi (micro-Curies) of tritiated thymidine ( H-thymidine) is added.
4. The cells were cultured for a further 16 hours and harvested.
5. The amount of radioactively labelled DNA was measured and the cpm (counts per minute) value recorded.
6. The relative increase in labelled DNA was compared to cells grown without the lymphokine.
The addition of Interleukin 10 (IL-10) induced a significant increase in proliferation (averaged over several experiments), since the DNA synthesis was up-regulated by 42% +/- 9%. The IL10 concentration was tested in the range 0.5 ng to 20 ng/ml and the proliferation was read at 8, 24 or 36 hrs.
These results clearly show that mantle cell lymphomas possess up-regulated IL-10 receptors leading to an increased cell survival rate, since IL-10 acts as a survival signal. By blocking the 11-10 receptor, for example with an anti-IL-10 antibody, a decrease in proliferation would occur, since the tumour cells are being deprived of an essential growth factor.