Use of CD36 to identify cancer subject for treatment

Abstract

To provide a method for identifying a cancer subject for treatment with a Psap peptide.SOLUTION: A subject is identified based on a level of CD36. Further provided herein are a composition and a method for treating a cancer subject based on the level of CD36.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of the filing date of U.S. Provisional Application No. 61 / 782,850, filed March 14, 2013, the entire contents of which are incorporated herein by reference.

[0002] Federally Sponsored Research or Development This invention was made with United States government support under R01CA135417 awarded by the National Cancer Institute. The United States government has certain rights in this invention. [Background technology]

[0003] Background of the Invention Cancer continues to be a major public health priority. For example, an estimated 7.6 million people died from cancer in 2008. Cancer treatments are constantly improving with advances in science and technology. Unfortunately, many cancer treatments are proving effective only in a subset of cancer patients, and even in a subset of patients with the same type of cancer. As a result, it is becoming increasingly important to find ways to identify patients who are likely to respond to treatment. Summary of the Invention

[0004] Aspects of the present disclosure are based in part on the discovery that elevated levels of CD36 in tumor cells indicate that a subject is responsive or likely to respond to treatment with a Psap peptide.Accordingly, aspects of the present disclosure relate to methods for assessing a subject's responsiveness to treatment with a Psap peptide by determining the level of CD36 in a sample, such as a tumor sample.In some embodiments, the methods described herein relate to identifying or selecting a subject for treatment with a Psap peptide based on the level of CD36 in the sample.Other aspects of the present disclosure relate to compositions and methods for treating a subject with cancer characterized by elevated levels of CD36.

[0005] In some aspects, the present disclosure relates to a method for assessing a subject's responsiveness to treatment with a Psap peptide, the method comprising determining the level of CD36 in a sample obtained from a subject with cancer, wherein an elevated level of CD36 in the sample compared to a control level indicates that the subject is responsive or likely to respond to treatment with the Psap peptide. In some embodiments, the level of CD36 in the sample is determined by performing an assay. In some embodiments, the method further comprises identifying a subject having an elevated level of CD36 in the sample compared to the control level as being responsive or likely to respond to treatment with the Psap peptide. In some embodiments, the method further comprises administering an effective amount of Psap peptide to treat the cancer to the subject identified as being responsive or likely to respond to treatment with the Psap peptide.

[0006] Another aspect of the present disclosure relates to a method for treating a subject with cancer, the method comprising administering to a subject having cancer and characterized by an elevated level of CD36 in a sample compared to a control level an effective amount of a Psap peptide for treating the cancer. In some embodiments, the control level is the level of CD36 in non-cancerous cells or tissue obtained from a subject with cancer. In some embodiments, the control level is the level of CD36 in cells or tissue obtained from a healthy subject or a population of healthy subjects. In some embodiments, the control level is a predetermined level. In some embodiments, the CD36 level is a CD36 protein level.

[0007] A further aspect of the present disclosure relates to a method for treating a subject with cancer, comprising: (a) selecting a subject with cancer based on the subject being known to have an elevated level of CD36 in a sample compared to a control level; and (b) administering to the subject an effective amount of a Psap peptide since the subject has an elevated level of CD36 in a sample compared to the control level. In some embodiments, the control level is the level of CD36 from non-cancerous cells or tissues obtained from a subject with cancer. In some embodiments, the level is the level of CD36 from cells or tissues obtained from a healthy subject or a population of healthy subjects. In some embodiments, the control level is a predetermined level. In some embodiments, the CD36 level is a CD36 protein level. In some embodiments of any of the methods provided herein, the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma.

[0008] In some embodiments of any of the methods provided herein, the Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or an amino acid substitution variant thereof, wherein the amino acid substitution is a) Tyrosine (Y) to tryptophan (W); b) an amino acid substitution selected from valine (V), alanine (A) or glycine (G) for leucine (L), or a non-standard amino acid of similar size, or a derivative thereof; c) arginine (R) for lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L); e) the L-isomer of tryptophan (W) versus the D-isomer of tryptophan (W), and / or the L-isomer of proline (P) versus the D-isomer of proline (P); or a combination thereof. In some embodiments, the Psap peptide is 50 amino acids or less in length. In some embodiments, the Psap peptide is 30 amino acids or less in length. In some embodiments, the Psap peptide is 15 amino acids or less in length. In some embodiments, the Psap peptide is 6 amino acids or less in length. In some embodiments, the Psap peptide is a cyclic peptide. In some embodiments, the similar-sized non-standard amino acid is methylvaline, methylleucine, or sarcosine.

[0009] In yet another aspect, the present disclosure relates to a composition containing a Psap peptide for use in treating a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level. In another aspect, the present disclosure relates to the use of a composition in the manufacture of a medicament for treating a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level, wherein the composition comprises a Psap peptide. In some embodiments of the uses or compositions provided herein, the control level is the level of CD36 from non-cancerous cells or tissues obtained from a subject with cancer. In some embodiments of the uses or compositions provided herein, the control level is the level of CD36 from cells or tissues obtained from a healthy subject or a population of healthy subjects. In some embodiments of the uses or compositions provided herein, the control level is a predetermined level. In some embodiments of the uses or compositions provided herein, the CD36 level is a CD36 protein level.

[0010] In some embodiments of the uses or compositions provided herein, the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma. In some embodiments of the uses or compositions provided herein, the Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or an amino acid substitution variant thereof, wherein the amino acid substitution is a) Tyrosine (Y) to tryptophan (W); b) an amino acid substitution for leucine (L) selected from valine (V), alanine (A), or glycine (G), or a non-standard amino acid of similar size, or a derivative thereof; c) arginine (R) to lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L);

[0011] e) the L-isomer of tryptophan (W) versus the D-isomer of tryptophan (W), and / or the L-isomer of proline (P) versus the D-isomer of proline (P); or a combination thereof. In some embodiments, the Psap peptide is 50 amino acids or less in length. In some embodiments, the Psap peptide is 30 amino acids or less in length. In some embodiments, the Psap peptide is 15 amino acids or less in length. In some embodiments, the Psap peptide is 6 amino acids or less in length. In some embodiments, the Psap peptide is a cyclic peptide. In some embodiments, the similar-sized non-standard amino acid is methylvaline, methylleucine, or sarcosine. In some embodiments of the methods, compositions, or uses provided herein, the sample is a tumor sample. [Brief explanation of the drawings]

[0012] [Figure 1] Figure 1A is a graph showing the proliferation of LLC cells 48 hours after the addition of serially diluted recombinant Tsp-1 or DWLPK (SEQ ID NO: 2) peptides, and Figure 1B is a photograph of a Western blot showing that CD36 protein is expressed in LLC cells. [Figure 2] Figure 2 is a photograph of a Western blot showing that CD36 protein is expressed in breast cancer (MDA-231, MCF-7), ovarian cancer (ID8), melanoma (B16), prostate cancer (PC3 and LNCaP), and lung cancer (LLC) cell lines. [Figure 3] FIG. 3 is a photograph of a Western blot showing that CD36 protein is expressed in primary ovarian cancer cells derived from patient ascites. [Figure 4] Figure 4 is a photograph of a Western blot showing that CD36 protein is expressed in pancreatic cancer (AsPC1), ovarian cancer (DF-14 and ID-8), breast cancer (MDA-MB231 and LM2), prostate cancer (PC3, PC3-M-LN4, LN-CAP, and LN-CAP-LN3), melanoma (B16-BL6), and lung cancer (LLC) cells. Representative high- and low-CD36-expressing cell lines are shown in the boxes.

[0013] [Figure 5] FIG. 5 is a graph showing that dWlP (SEQ ID NO: 47) peptide caused cancer regression in a cancer model expressing high levels of CD36. [Figure 6] FIG. 6 is a graph showing that CD36-expressing ovarian cancer cells are susceptible to Tsp-1-mediated cell killing. [Figure 7] 7 is a graph showing the primary tumor mass of mice treated with dWlP (SEQ ID NO: 47) peptide or control after injection of AsPC pancreatic cancer cells expressing high levels of CD36. The primary tumor mass was inhibited by peptide treatment. [Figure 8] FIG. 8 is a graph showing that treatment of mice bearing B16-BL6 melanoma tumors (expressing low levels of CD36) with dWlP (SEQ ID NO: 47) peptide inhibited tumor growth but did not cause tumor regression. Detailed Description of the Invention

[0014] Psap peptides are therapeutic peptides containing an amino acid sequence originally derived from a fragment of saposin A, a known anti-angiogenic protein. Psap peptides generally contain the core sequence of CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or amino acid substitution variants thereof, and can be as little as four amino acids in length (e.g., a peptide consisting of DWLP (SEQ ID NO: 3) or an amino acid substitution variant). Such Psap peptides have previously been shown to be effective in treating multiple types of cancer (see, e.g., PCT Publications WO2009002931 and WO / 2011 / 084685; PCT Application PCT / US2012 / 71424, published as PCT Publication WO / 2013 / 096868; and U.S. Patent Applications 12 / 640788 and 13 / 516511, all of which are incorporated herein by reference in their entireties). Administration of Psap peptides was previously thought to stimulate thrombospondin (Tsp-1) in vivo, which in turn acts on endothelial cells to cause an antiangiogenic effect leading to indirect inhibition of cancer and / or metastasis growth.

[0015] As described herein, tumor cells from several different types of cancers responsive to Psap peptides have been found to express CD36. CD36 is a member of the class B scavenger receptor family of cell surface proteins and has many ligands, including oxidized low-density lipoprotein, oxidized phospholipids, long-chain fatty acids, collagen, and Tsp-1. Without wishing to be bound by any theory or mechanism, it is believed that administration of Psap peptides stimulates Tsp-1, which then acts directly on tumor cells by interacting with CD36 on the tumor cells. The interaction between Tsp-1 and CD36 on tumor cells can result in the inhibition of tumor cell proliferation and / or the induction of tumor cell apoptosis. Thus, Psap peptides appear to treat cancer through two distinct and independent mechanisms: indirectly through antiangiogenic effects and directly through the interaction of CD36 with Tsp-1 on tumor cells. Therefore, the responsiveness of cancer-bearing subjects to treatment with Psap peptides may depend on the level of CD36 expressed by the cancer.

[0016] Thus, aspects of the present disclosure relate to methods for assessing a subject's responsiveness to treatment with a Psap peptide by determining the level of CD36 in a sample, such as a tumor sample. In some embodiments, the methods described herein relate to identifying or selecting a subject for treatment with a Psap peptide based on the level of CD36 in a sample, such as a tumor sample. Other aspects of the present disclosure relate to compositions and methods for treating a subject having cancer and characterized by elevated levels of CD36 (e.g., selecting or identifying a subject based on the cancer having elevated levels of CD36 in the sample compared to control levels). As used herein, "responsive to treatment with a Psap peptide" includes, but is not limited to, preventing or alleviating cancer development, alleviating cancer symptoms, suppressing or inhibiting cancer growth, preventing metastasis and / or invasion of existing cancer, promoting or inducing cancer regression, inhibiting or suppressing cancer cell proliferation, reducing angiogenesis and / or increasing the amount of apoptotic cancer cells in response to treatment with a Psap peptide.

[0017] As used herein, "not responsive to treatment with a Psap peptide" includes, but is not limited to, the following: absence of prevention or alleviation of cancer development, absence of alleviation of cancer symptoms, absence of suppression or inhibition of cancer growth, absence of prevention of metastasis and / or invasion of existing cancer, absence of promotion or induction of cancer regression, absence of inhibition or suppression of cancer cell proliferation, absence of reduction in angiogenesis and / or reduction in the amount of apoptotic cancer cells in response to treatment with a Psap peptide.

[0018] Diagnostic and Theranostic Methods Aspects of the present disclosure relate to diagnostic and theranostic methods useful for assessing a subject's responsiveness to treatment with a Psap peptide. In some embodiments, the methods include determining the level of CD36 in a sample obtained from a subject with cancer, where an elevated level of CD36 in the sample compared to a control level indicates that the subject is responsive or likely to respond to treatment with a Psap peptide (i.e., if the level of CD36 in the sample is higher than the control level, the subject is identified as being responsive or likely to respond to treatment with a Psap peptide). In some embodiments, the methods further include identifying a subject with an elevated level of CD36 in the sample compared to a control as being responsive or likely to respond to treatment with a Psap peptide. In some embodiments, the methods further include administering an effective amount of a Psap peptide described herein for treating cancer to a subject identified as being responsive or likely to respond to treatment with a Psap peptide. In some embodiments, the sample obtained from a subject with cancer is a tumor sample.

[0019] In some embodiments, an elevated level of CD36 in the sample compared to the control level indicates that the cancer will regress or is likely to regress in response to treatment with the Psap peptide. In some embodiments, the method further comprises identifying a subject having an elevated level of CD36 in the sample compared to the control as having a cancer that will regress or is likely to regress in response to treatment with the Psap peptide. In some embodiments, the method further comprises administering to a subject identified as having a cancer that will regress or is likely to regress in response to treatment with the Psap peptide an effective amount of a Psap peptide described herein to cause cancer regression.

[0020] As used herein, "elevated levels of CD36" means that the level of CD36 is above a predetermined threshold or a control level, such as the level of CD36 in a control sample. Control levels are described in detail herein. Elevated levels of CD36 include, for example, 1%, 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, 150%, 200%, 300%, 400%, 500%, or more CD36 levels higher than the control level. Elevated levels of CD36 also include an increase from a zero state (e.g., no or undetectable CD36 expression in the control) to a non-zero state (e.g., some or detectable CD36 expression in the sample). As used herein, "treatment with a Psap peptide" refers to administration of a Psap peptide to a subject. Psap peptides are described herein. Treatment with a Psap peptide may include treatment with a Psap peptide alone or may include treatment with multiple agents or therapies, such as a Psap peptide and other chemotherapeutic agents, and / or other forms of treatment, such as surgery, radiation therapy, or chemotherapy.

[0021] treatment Another aspect of the present disclosure relates to methods for treating a subject having cancer. In some embodiments, the methods comprise administering to a subject having cancer and characterized by an elevated level of CD36 in a sample obtained from the subject compared to a control level an effective amount of a Psap peptide described herein to treat the cancer. In some embodiments, the methods comprise: (a) selecting a subject with cancer based on the subject being known to have an elevated level of CD36 in a sample compared to a control level; and (b) administering to the subject an effective amount of a Psap peptide, such that the subject has an elevated level of CD36 in the sample compared to a control level; Includes. Other aspects of the present disclosure relate to compositions and uses of compositions in the manufacture of medicaments for treating a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level. In some embodiments, the composition comprises a Psap peptide as described herein. In some embodiments, the sample is a tumor sample.

[0022] As used herein, "treating" or "treatment" includes, but is not limited to, preventing or alleviating the development of cancer, alleviating the symptoms of cancer, suppressing or inhibiting the growth of cancer, preventing metastasis and / or invasion of existing cancer, promoting or inducing the regression of cancer, inhibiting or suppressing the proliferation of cancer cells, reducing angiogenesis and / or increasing the amount of apoptotic cancer cells. In some embodiments, treating cancer involves directly inhibiting or suppressing the proliferation of cancer cells and does not involve inhibiting or suppressing angiogenesis (which indirectly results in the inhibition or suppression of cancer cell proliferation). An effective amount is a dosage of Psap peptide sufficient to provide a medically desirable result, such as the treatment of cancer. Effective amounts vary depending on the particular cancer being treated, the age and physical condition of the subject being treated, the severity of the condition, the duration of treatment, the nature of any concomitant therapy, the particular route of administration, and similar factors within the knowledge and experience of the physician. For administration to subjects, such as humans, dosages from about 0.001, 0.01, 0.1, or 1 mg / kg up to 50, 100, 150, or 500 mg / kg or more can generally be used.

[0023] Psap peptides and compositions thereof can be formulated for various modes of administration, including systemic, topical, or local administration. Techniques and dosage forms can generally be found in the latest edition of Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa. When administered, Psap peptides can be applied in pharmaceutically acceptable amounts and pharmaceutically acceptable compositions. Such preparations may routinely contain salts, buffers, preservatives, compatible carriers, and optionally other therapeutic agents. When used in medicine, salts should be pharmaceutically acceptable; however, pharmaceutically unacceptable salts may also be used to prepare pharmaceutically acceptable salts and are not excluded from the scope of this disclosure. Such pharmacologically and pharmaceutically acceptable salts include, but are not limited to, those prepared from the following acids: hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, maleic acid, acetic acid, salicylic acid, citric acid, formic acid, malonic acid, succinic acid, etc. Also, pharmaceutically acceptable salts can be prepared as alkaline metal or alkaline earth salts, such as sodium, potassium or calcium salts.

[0024] The Psap peptide can be optionally combined with a pharmaceutically acceptable carrier. As used herein, the term "pharmaceutically acceptable carrier" refers to one or more compatible solid or liquid fillers, diluents, or encapsulating substances suitable for human administration. The term "carrier" refers to a natural or synthetic organic or inorganic component with which an active ingredient is combined to facilitate application. The components of the pharmaceutical composition can also be co-mixed with the molecules of the present disclosure, and with each other, in a manner such that there is no interaction that would substantially impair the desired pharmaceutical effect. Some examples of materials that can serve as pharmaceutically acceptable carriers include: (1) sugars such as lactose, glucose, and sucrose; (2) starches such as corn starch and potato starch; (3) cellulose and its derivatives such as sodium carboxymethylcellulose, methylcellulose, ethylcellulose, microcrystalline cellulose, and cellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7) lubricants such as magnesium stearate, sodium lauryl sulfate, and talc; (8) excipients such as cocoa butter and suppository wax; (9) oils such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil, and soybean oil; (10) glycols such as propylene glycol (11) polyols, such as glycerin, sorbitol, mannitol, and polyethylene glycol (PEG); (12) esters, such as ethyl oleate and ethyl laurate; (13) agar; (14) buffers, such as magnesium hydroxide and aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17) isotonic saline; (18) Ringer's solution; (19) ethyl alcohol; (20) pH buffer solutions; (21) polyesters, polycarbonates, and / or polyanhydrides; (22) bulking agents, such as polypeptides and amino acids; (23) serum components, such as serum albumin, HDL, and LDL; (24) C2-C22 alcohols, such as ethanol; and (25) other non-toxic, compatible substances used in pharmaceutical formulations.Wetting agents, coloring agents, releasing agents, coating agents, sweetening agents, flavoring agents, perfuming agents, preservatives and antioxidants can also be present in the formulation.

[0025] The pharmaceutical compositions can be conveniently provided in unit dosage form and can be prepared by any method well known in the art of pharmacy. The term "unit dose" as used in connection with the pharmaceutical compositions of the present disclosure refers to physically discrete units suitable as unitary dosages for subjects, each unit containing a predetermined quantity of active substance calculated to produce the desired therapeutic effect in association with the required diluent, such as a carrier or vehicle. Various administration routes are available. The particular mode selected depends on the type of cancer to be treated and the dosage required for therapeutic effect. The method of the present disclosure can generally be carried out using any medically acceptable mode of administration, meaning any mode that produces an effective level of the active compound without causing clinically unacceptable side effects. Such modes of administration include oral, rectal, topical, nasal, intradermal, or parenteral routes. The term "parenteral" includes subcutaneous, intravenous, intramuscular, or infusion.

[0026] In some embodiments, administration is parenteral. Injectable preparations suitable for parenteral administration include, for example, sterile injectable aqueous or oily suspensions, which can be formulated according to well-known techniques using appropriate dispersing or wetting agents and suspending agents. Sterile injectable preparations can also be sterile injectable solutions, suspensions, or emulsions in non-toxic parenterally acceptable diluents or solvents, such as solutions in 1,3-propanediol or 1,3-butanediol. Acceptable vehicles and solvents that can be used include water, Ringer's solution, USP, and isotonic sodium chloride solution. Additionally, sterile fixed oils are conventionally used as solvents or suspending media. For this purpose, any non-irritating fixed oil can be used, including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables. Injectable preparations can be sterilized, for example, by filtration through a bacteria-retaining filter, or by incorporating a sterilizing agent in the form of a sterile solid composition that can be dissolved or dispersed in sterile water or other sterile injectable medium before use.

[0027] For topical administration, pharmaceutical compositions can be formulated into ointments, salves, gels, or creams, as commonly known in the art. Topical administration can utilize transdermal delivery systems known in the art. Examples include skin patches. Alternatively, biolistic gene gun delivery methods can be used. Gene guns are devices for injecting genetic information into cells, originally designed for plant transformation. The payload is heavy metal elemental particles coated with plasmid DNA. This technology is often simply referred to as biolistics. Another device using biolistic technology is the PDS-1000 / He particle delivery system. The compositions described herein can be coated onto microscopic gold particles, and these coated particles are "fired" under high pressure into living tissues such as hemangiomas and melanomas. An example of a gene gun-based method for DNA-based vaccination of cattle is described in Loehr BI et al., J. Virol. 2000, 74:6077-86.

[0028] The pharmaceutical compositions described herein can also be administered by intratumoral, peritumoral, intralesional or perilesional routes to exert local and systemic effects.Intraperitoneal route is expected to be particularly useful, for example, in the treatment of ovarian tumors.For these uses, additional conventional pharmaceutical preparations, such as tablets, granules, powders, capsules and sprays, may be required preferentially.In such preparations, additional conventional additives, such as binders, wetting agents, propellants, lubricants and stabilizers, may also be required. Compositions suitable for oral administration can be presented as discrete units such as capsules, tablets, lozenges, each containing a predetermined amount of the anti-inflammatory agent. Other compositions include suspensions in aqueous liquids or non-aqueous liquids such as a syrup, elixir, or emulsion.

[0029] Other delivery systems can include time-release, delayed-release, or sustained-release delivery systems. Such systems can avoid repeated administration of anti-inflammatory drugs, increasing convenience for patients and physicians. Many types of release delivery systems are available and known to those skilled in the art. These include polymer-based systems, such as poly(lactide-glycolide), copolyoxalates, copolycaprolactones, polyesteramides, polyorthoesters, polyhydroxybutyric acid, and polyanhydrides. Drug-containing microcapsules of the aforementioned polymers are described, for example, in U.S. Patent 5,075,109. Delivery systems also include non-polymeric systems, such as lipids containing sterols such as cholesterol, cholesterol esters, and fatty acids or neutral lipids, e.g., mono-, di-, and triglycerides; hydrogel release systems; silastic systems; peptide-based systems; wax coatings; compressed tablets using conventional binders and excipients; and partially fused implants. Specific examples include, but are not limited to: (a) erosion systems in which the anti-inflammatory agent is contained within a matrix, as described, for example, in U.S. Patent Nos. 4,452,775, 4,667,014, 4,748,034, and 5,239,660, and (b) diffusion systems in which the active ingredient permeates through a polymer at a controlled rate, as described, for example, in U.S. Patent Nos. 3,832,253 and 3,854,480. Additionally, pump-based hardware delivery systems can be used, some of which are adapted for implantation.

[0030] The use of long-term sustained release implants may be particularly suitable for the treatment of chronic conditions.As used herein, long-term release means that the implant is constructed and configured to deliver therapeutic levels of active ingredients for at least 30 days, preferably 60 days.Long-term sustained release implants are well known to those skilled in the art and include some of the release systems described above.

[0031] In some embodiments, pharmaceutical compositions used for therapeutic administration must be sterile. Sterility is achieved by filtration through a sterile filtration membrane (e.g., a 0.2 micron membrane). Alternatively, preservatives can be used to prevent the growth or action of microorganisms. Various preservatives are well known, including, for example, phenol and ascorbic acid. If the active ingredient and / or pharmaceutical composition is highly stable against heat and oxidative denaturation, it is usually stored in lyophilized form or as an aqueous solution. The pH of the formulation is typically about 6 to 8, although higher or lower pH values ​​may be appropriate in certain cases. In some embodiments, administration of Psap peptides may be combined with other therapies, such as chemotherapy, radiation and / or surgery.

[0032] CD36 CD36 (cluster of differentiation 36) is an integral membrane protein found on the surface of many vertebrate cell types; it is also known as FAT, GP4, GP3B, GPIV, CHDS7, PASIV, SCARB3, and BDPLT10. The Entrez gene ID for human CD36 is 948. Exemplary human CD36 transcripts and proteins are as follows: [Table 1-1] [Table 1-2]

[0033] [Table 2]

[0034] [Table 3]

[0035] [Table 4]

[0036] [Table 5]

[0037] [Table 6]

[0038] Psap peptides Prosaposin (Psap) is a precursor protein of saposins, consisting of approximately 524–527 amino acids, including a 16-amino acid signal peptide. The full-length precursor polypeptide undergoes cotranslational glycosylation and modification in the endoplasmic reticulum and Golgi system to produce a 70–72 kDa precursor protein. After transport to the lysosome, cathepsin D mediates proteolytic processing, producing a 35–53 kDa intermediate form, then a 13 kDa glycoprotein, and finally the mature 8–11 kDa partially glycosylated form of the individual saposin molecule (O'Brien JS, and Kishimoto Y, The FASEB J., 5: 301–8, 1991; Kishimoto Y. et al., J. Lipid Res., 33:1255–67, 1992). Prosaposin is converted to four cleavage products, saposin A, B, C, and D. The amino acid sequences of Psap preproprotein isoforms A, B, and C, and the amino acid sequence of the saposin A cleavage product are as follows:

[0039] [Table 7]

[0040] [Table 8]

[0041] [Table 9] [Table 10]

[0042] Aspects of the present disclosure relate to Psap peptides and uses thereof. Psap peptides comprise sequences originally derived from fragments of saposin A. Fragments of saposin A consisting of as few as four amino acids and variants of these fragments have previously been shown to have anti-angiogenic and anti-cancer activity. Psap peptides and methods for making Psap peptides are known in the art (see, e.g., PCT Publications WO2009002931 and WO / 2011 / 084685; PCT Application PCT / US2012 / 71424, published as PCT Publication WO / 2013 / 096868; and U.S. Patent Applications 12 / 640,788 and 13 / 516,511; all of which are incorporated herein by reference in their entireties).

[0043] In some embodiments, the Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or an amino acid substitution variant thereof, wherein the amino acid substitution is a) Tyrosine (Y) to tryptophan (W); b) an amino acid substitution selected from valine (V), alanine (A) or glycine (G) for leucine (L), or a non-standard amino acid of similar size, or a derivative thereof; c) arginine (R) for lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L); e) the L-isomer of tryptophan (W) versus the D-isomer of tryptophan (W), and / or the L-isomer of proline (P) versus the D-isomer of proline (P); or a combination thereof. In some embodiments, the Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3).

[0044] It should be understood that the Psap peptide can be of any length, hi some embodiments, the Psap peptide is 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 33, 34, 35, 36, 37, 38, 39, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 or more amino acids in length. In some embodiments, the Psap peptide is 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 33, 34, 35, 36, 37, 38, 39, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 200, 300, 400, 500 or fewer amino acids in length. In some embodiments, the Psap peptide is between 4 and 500, 4 and 400, 4 and 300, 4 and 200, 4 and 100, 4 and 90, 4 and 80, 4 and 70, 4 and 60, 4 and 50, 4 and 40, 4 and 30, 4 and 25, 4 and 20, 5 and 500, 5 and 400, 5 and 300, 5 and 200, 5 and 100, 5 and 90, 5 and 80, 5 and 70, 5 and 60, 5 and 50, 5 and 40, 5 and 30, 5 and 25, 5 and 20, 6 and 500, 6 and 400, 6 and 300, 6 and 200, 6 and 100, 6 and 90, 6 and 80, 6 and 70, 6 and 60, 6 and 50, 6 and 40, 6 and 30, 6 and 25, or 6 and 20 amino acids in length.

[0045] The amino acids flanking CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3) may be naturally adjacent amino acids present in saposin A or prosaposin (e.g., LEKTC DWLP KPNMS(SEQ ID NO:14, where the underlined amino acids are those naturally adjacent to DWLP (SEQ ID NO:3) of saposin A.) Thus, in some embodiments, the Psap peptide comprises the amino acid sequence DWLPKPNMS (SEQ ID NO:15), CDWLPKPNM (SEQ ID NO:16), TCDWLPKPN (SEQ ID NO:17), KTCDWLPKP (SEQ ID NO:18), EKTCDWLPK (SEQ ID NO:19), LEKTCDWLP (SEQ ID NO:20), or an amino acid substitution variant thereof, wherein the substitution occurs in CDWLPK (SEQ ID NO:1), DWLPK (SEQ ID NO:2), or DWLP (SEQ ID NO:3). Other examples of Psap peptides include, without limitation, the following: DWLPKPNMS (SEQ ID NO:21), CDWLPKPNM (SEQ ID NO:22), TCDWLPKPN (SEQ ID NO:23), KTCDWLPKP (SEQ ID NO:24), EKTCDWLPK (SEQ ID NO:25), and LEKTCDWLP (SEQ ID NO:26). Examples of other Psap peptides include, but are not limited to, the following: DWLPKPNM (SEQ ID NO:27), CDWLPKPN (SEQ ID NO:28), TCDWLPKP (SEQ ID NO:29), KTCDWLPK (SEQ ID NO:30), EKTCDWLP (SEQ ID NO:31), DWLPKPN (SEQ ID NO:32), CDWLPKP (SEQ ID NO:33), TCDWLPK (SEQ ID NO:34), KTCDWLP (SEQ ID NO:35), DWLPKP (SEQ ID NO:36), CDWLPK (SEQ ID NO:1), TCDWLP (SEQ ID NO:37), DWLPK (SEQ ID NO:2), CDWLP (SEQ ID NO:38), and DWLP (SEQ ID NO:3).

[0046] It should also be understood that the amino acids flanking CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3) need not be the amino acids naturally flanking saposin A or prosaposin, but can instead be any amino acids. Thus, a Psap peptide can include any number and identity of amino acids flanking an amino acid. In some embodiments, the flanking amino acids may include an antibody or Fc domain of an antibody, serum transferrin or a portion thereof, albumin, or transthyretin (see, e.g., G.M. Subramanian, (2007), Nature Biotechnology 25, 1411-141).

[0047] Psap peptides can be synthesized using any method known in the art. Examples of synthetic methods include, but are not limited to, recombinant synthesis, solution phase synthesis, solid phase synthesis, and chemical ligation (see, e.g., Molecular Cloning: A Laboratory Manual, J. Sambrook, et al., eds., Third Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2001; Current Protocols in Molecular Biology, F. M. Ausubel, et al., eds., John Wiley & Sons, Inc., New York; Schnolzer, MA, P.; Jones, A.; Alewood, D.; Kent, SBH (2007). "In Situ Neutralization in Boc-chemistry Solid Phase Peptide Synthesis". Int. J. Peptide Res. Therap. 13 (1-2): 31-44; Albericio, F. (2000). Solid-Phase Synthesis: A Practical Guide (1 ed.). Boca Raton: CRC Press. p. 848; and Nilsson BL, Soellner MB, Raines RT (2005). "Chemical Synthesis of Proteins". Annu. Rev. Biophys. Biomol. Struct. 34: 91-118; and U.S. Patent Nos. 4,749,742, 4,794,150, 5,552,471, 5,637,719, 6,001,966, 7,038,103, 7,094,943, 7,176,282, and 7,645,858; which are incorporated herein by reference in their entireties.

[0048] In some embodiments, the Psap peptides can be modified, for example, by oligomerization or polymerization (e.g., dimers, trimers, multimers, etc.), modification of amino acid residues or the peptide backbone, crosslinking, cyclization, conjugation, pegylation, glycosylation, acetylation, phosphorylation, fusion to additional heterologous amino acid sequences (e.g., antibodies or Fc domains of antibodies, serum transferrin or portions thereof, albumin, or transthyretin), or other modifications that substantially alter the stability, solubility, or other properties of the peptide while substantially retaining or improving therapeutic activity. Conjugation can be, for example, to a polymer. Suitable polymers include, for example, polyethylene glycol (PEG), polyvinylpyrrolidone, polyvinyl alcohol, polyamino acids, divinyl ether maleic anhydride, N-(2-hydroxypropyl)-methacrylamide, dextran, dextran derivatives including dextran sulfate, polypropylene glycol, polyoxyethylated polyols, heparin, heparin fragments, polysaccharides, cellulose and cellulose derivatives including methylcellulose and carboxymethylcellulose, starch and starch derivatives, polyalkylene glycols and derivatives thereof, copolymers of polyalkylene glycols and derivatives thereof, polyvinyl ethyl ether, and α,β-poly[(2-hydroxyethyl)-DL-aspartamide], or mixtures thereof. Conjugation may be via a linker, such as a peptide or chemical linker. Methods for modifying peptides are known in the art (see, e.g., U.S. Patent Nos. 5,180,816, 5,596,078, 5,990,273, 5,766,897, 5,856,456, 6,423,685, 6,884,780, 7,610,156, 7,256,258, 7,589,170, and 7,022,673, and PCT Publication WO 2010 / 014616, the contents of which are incorporated herein by reference).

[0049] In some embodiments, the Psap peptide is a cyclic peptide. A cyclic peptide is a polypeptide chain whose amino and carboxyl termini are linked by a peptide bond or other covalent bond to form a circular chain. In one embodiment, the peptide contains amino- and carboxyl-terminal cysteine ​​amino acid residues. The cysteine ​​promotes S-S disulfide bond formation. In one embodiment, the peptide contains an additional cysteine ​​amino acid residue, where the cysteine ​​amino acid residue is near the terminus, but not necessarily at the very end. In some embodiments, the cysteine ​​amino acid residue is within five amino acid residues of the terminus of the peptide. Methods for designing and synthesizing cyclic peptides are well known in the art and are described, for example, in U.S. Patent Nos. 5,596,078, 5,990,273, 7,589,170, and U.S. Patent Application No. 20080287649.

[0050] In some embodiments, the Psap peptide is functionally modified to enhance stability. In some embodiments, the Psap peptide comprises an N-terminal acetyl group and / or a C-terminal amide group. In some embodiments, the Psap peptide comprises an N-terminal acetyl group and a C-terminal amide group. In some embodiments, the Psap peptide is Ac-dWlP-amide or Ac-DWLP-amide (Ac = acetyl group; lowercase D and L represent D-amino acids of SEQ ID NOs: 39 and 40, respectively). In some embodiments, chemical modifications of the Psap peptide include, but are not limited to, alkyl, alkoxy, hydroxyalkyl, alkoxyalkyl, alkoxycarbonyl, alkenyl, alkynyl, cycloalkyl, amino, alkylamino, aminoalkyl, dialkylamino, aminodialkyl, halogen, heteroatom, carbocycle, carbocyclyl, carbocyclo, carbocyclic, aryl, aralkyl, aralkoxy, aryloxyalkyl, heterocycle, heterocyclyl, heterocyclic, heteroaryl, and / or aliphatic groups.

[0051] Psap peptides also encompass peptidomimetics (e.g., D-peptides, β-peptides, and peptoids). The peptidomimetics utilized can encompass the entire Psap peptide or only a portion of the Psap peptide. Peptidomimetics may include, for example, D-amino acids, reduced amide bonds for the peptide backbone, and non-peptide bonds for linking side chains, pyrrolinones, and glycomimetics. The design and synthesis of sugar-scaffold peptidomimetics has been described by Hirschmann et al. (J. Med. Chem., 1996, 36, 2441-2448; incorporated herein by reference in its entirety). Additionally, pyrrolinone-based peptidomimetics have also been described (see, e.g., Smith et al., J. Am. Chem. Soc. 2000, 122, 11037-11038; incorporated herein by reference in its entirety). In some embodiments, the Psap peptide is in the form of a peptoid (U.S. Pat. No. 5,811,387; Simon et al. Proceedings of the National Academy of Sciences USA, (1992), 89(20), 9367-9371). In some embodiments, the peptoid is a poly-N-substituted glycine. In peptoids, the side chain is attached to the nitrogen of the peptide backbone, rather than to the alpha carbon as in peptides. In some embodiments, the peptoid contains a nitroaromatic monomer unit (Fowler et al., J Org Chem. 2009 Feb 20;74(4):1440-9). In some embodiments, the peptoid is N-substituted at one or more residues with an alpha chiral aromatic side chain (Gorske et al., J Am Chem Soc. 2006 Nov 8;128(44):14378-87). In some embodiments, the Psap peptide comprises a peptoid region (i.e., comprising one or more side chains attached to a nitrogen of the peptide backbone) and a peptidic region (i.e., comprising one or more side chains attached to an alpha carbon).

[0052] Psap amino acid substitutions In some embodiments, the Psap peptide comprises an amino acid substitution variant of CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), wherein the amino acid substitution is: a) Tyrosine (Y) to tryptophan (W); b) an amino acid substitution for leucine (L) selected from valine (V), alanine (A), or glycine (G), or a non-standard amino acid of similar size, or a derivative thereof; c) arginine (R) to lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L); e) the L-isomer of tryptophan (W) versus the D-isomer of tryptophan (W), and / or the L-isomer of proline (P) versus the D-isomer of proline (P); or a combination thereof.

[0053] Conservative amino acid substitution can be the substitution of one amino acid residue with one amino acid residue having a side chain with similar charge, size, polarity, hydrophobicity, or a combination thereof. Families of amino acid residues with side chains with similar charges have been defined in the art. These families include amino acids with: basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), β-branched side chains (e.g., threonine, valine, isoleucine), and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine).

[0054] Conservative amino acid substitutions typically do not change the overall structure of the peptide and / or the type of amino acid side chain available to form van der Waals bonds with a binding partner. In some embodiments, a conservative substitution for leucine is valine. In some embodiments, a conservative substitution for leucine is valine or alanine. In some embodiments, conservative or non-conservative substitutions for leucine are contemplated. In some embodiments, the substitution for leucine is valine, glycine, or alanine. In some embodiments, the substitution for leucine is glycine. In some embodiments, the substitution for leucine is glycine or valine. In some embodiments, the amino acid substitution is tyrosine (Y) for tryptophan (W). Exemplary amino acid substitution variants include, but are not limited to, DWAP (SEQ ID NO: 41), DYLPK (SEQ ID NO: 42), DWVPK (SEQ ID NO: 43), DWLPR (SEQ ID NO: 44), DWAPK (SEQ ID NO: 45), and DYLP (SEQ ID NO: 46).

[0055] Substitution with non-standard amino acids is also contemplated herein. In some embodiments, leucine is substituted with a non-standard amino acid. In some embodiments, the non-standard amino acid substitution for leucine has a size similar to leucine, valine, alanine, or glycine. Examples of non-standard amino acids include azidoalanine, azidohomoalanine, azidonorvaline, azidonorleucine, azidonorvaline, homoallylglycine, homopropargylglycine, norvaline, norleucine, ciscrotylglycine, transcrotylglycine, 2-aminoheptanoic acid, 2-butynylglycine, allylglycine, 3-(1-naphthyl)alanine, 3-(2-naphthyl)alanine, p-ethynyl-phenylalanine, p-propargyl-oxy-phenylalanine, m-ethynyl-phenylalanine, 3-(6-chloroindolyl)alanine, 3-(6-bromoindolyl)alanine, 3-(5-bromoindolyl)alanine, azidohomoalanine, homopropargylglycine, p-chlorophenylalanine, α-aminocaprylic acid, methylvaline, methylleucine, or sarcosine. In some embodiments, leucine is substituted with a non-standard amino acid selected from methylvaline, methylleucine, or sarcosine. Non-standard amino acids and methods for their synthesis are well known in the art (see, e.g., U.S. Patent Publications 2010-0247433, 2008-0214439, 2004-0053390, and 2004-0058415; PCT Publication WO 03 / 073238; and U.S. Patent No. 6,586,207; all of which are incorporated herein by reference).

[0056] Amino acid substitutions can be achieved during chemical synthesis of the peptide by adding the desired replacement amino acid in the appropriate order of the synthetic process. Alternatively, molecular biology methods can be used. Non-conservative substitutions are also encompassed to the extent that they substantially retain the activity of the peptides described herein. As previously described, Psap peptides containing CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3) and having D-amino acid substitutions have also been shown to possess desirable therapeutic activity (see PCT Application No. PCT / US2012 / 71424, published as PCT Publication WO / 2013 / 096868). Thus, amino acid substitution variants resulting from the substitution of one or more D-amino acids for the analogous L-amino acids are also contemplated herein. In some embodiments, there is one D-amino acid substitution. In some embodiments, there are two or more D-amino acid substitutions. In some embodiments, there are three, four, or five D-amino acid substitutions. In some embodiments, the D-amino acid substitutions are evenly spaced, e.g., at every other amino acid in a 4-6-mer. In some embodiments, the D-amino acid substitutions are for tryptophan (W) and / or proline (P). In some embodiments, the D-amino acid substitutions are for aspartic acid (D) and / or leucine (L). The L and D rule for amino acid composition refers to the optical activity of the isomer of glyceraldehyde from which the amino acid can theoretically be synthesized, not the optical activity of the amino acid itself (D-glyceraldehyde is dextrorotatory; L-glyceraldehyde is levorotatory). Exemplary D-amino acid substitutions include dWlP and DwLp (the lowercase D and L refer to the D-amino acids of SEQ ID NOs: 47 and 48, respectively).

[0057] Assay Aspects of the present disclosure relate to performing an assay for determining the level of CD36 in a sample. The level of CD36 can be measured using any assay known in the art (see, for example, Molecular Cloning: A Laboratory Manual, J. Sambrook, et al., eds., Third Edition, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, New York, 2001; Current Protocols in Molecular Biology, F.M. Ausubel, et al., eds., John Wiley & Sons, Inc., New York). Microarray technology is described in Microarray Methods and Protocols, R. Matson, CRC Press, 2009, or Current Protocols in Molecular Biology, F.M. Ausubel, et al., eds., John Wiley & Sons, Inc., New York). The level of CD36 can be at the mRNA level and / or protein level. In some embodiments, the level of CD36 is at the protein level.Assays for detecting CD36 mRNA include, but are not limited to, Northern blot analysis, RT-PCR, sequencing techniques, RNA in situ hybridization (e.g., using a DNA or RNA probe to hybridize to RNA molecules present in a sample), in situ RT-PCR (as described in Nuovo GJ, et al. Am J Surg Pathol. 1993, 17: 683-90; Komminoth P, et al. Pathol Res Pract. 1994, 190: 1017-25), and oligonucleotide microarrays (e.g., by hybridization of polynucleotide sequences from a sample to oligonucleotides attached to a solid surface (e.g., a glass wafer) having addressable locations, such as an Affymetrix microarray (Affymetrix®, Santa Clara, CA)). Methods for designing nucleic acid binding partners, such as probes, are known in the art. In some embodiments, the nucleic acid binding partner binds to a portion or the entire nucleic acid sequence of CD36, which sequence is distinguishable using the CD36 sequences provided herein.

[0058] Assays for detecting CD36 protein levels include, but are not limited to, immunoassays (herein referred to as immune-based or immuno-based assays, e.g., Western blot, immunohistochemistry, and ELISA assays), mass spectrometry, and multiplexed bead-based assays. Such assays for detecting protein levels are well known in the art. Binding partners for protein detection can be designed using methods known in the art, as described herein. In some embodiments, the CD36 protein binding partner, e.g., an anti-CD36 antibody, binds to a portion or the entire amino acid sequence of the CD36 protein. Other examples of protein detection and quantification methods include multiplexed immunoassays, such as those described in U.S. Pat. Nos. 6,939,720 and 8,148,171, and published U.S. patent application 2008 / 0255766, and protein microarrays, such as those described in U.S. patent application 2009 / 0088329. In some embodiments, the sample obtained from the subject is a tumor biopsy, and the assay for detecting CD36 protein levels is an immuno-based assay performed on the tumor biopsy.

[0059] Any suitable binding partner for CD36 is contemplated for detecting the level of CD36. In some embodiments, the binding partner is any molecule that specifically binds to CD36 protein. As used herein, "specifically binds to CD36 protein" means that the molecule is more likely to bind to a part or the whole of CD36 protein than to a part or the whole of non-CD36 protein. In some embodiments, the binding partner is an antibody or an antigen-binding fragment thereof, such as Fab, F(ab)2, Fv, single-chain antibody, Fab and sFab fragments, F(ab')2, Fd fragment, scFv, or dAb fragment. Methods for producing antibodies or antigen-binding fragments thereof are well known in the art (see, for example, Sambrook et al., "Molecular Cloning: A Laboratory Manual" (2nd Ed.), Cold Spring Harbor Laboratory Press (1989); Lewin, "Genes IV", Oxford University Press, New York, (1990); and Roitt et al., "Immunology" (2nd Ed.), Gower Medical Publishing, London, New York (1989); WO2006 / 040153, WO2006 / 122786, and WO2003 / 002609). Binding partners also include other peptide molecules and aptamers that specifically bind to CD36. Methods for producing peptide molecules and aptamers are well known in the art (see, e.g., published U.S. patent application 2009 / 0075834, U.S. Patent Nos. 7,435,542, 7,807,351, and 7,239,742).

[0060] Commercially available CD36 antibodies include, for example, N-15, SMφ, L-17, ME542, H300, 185-1G2, and V-19 from Santa Cruz Biotechnology (catalog numbers sc-5522, sc-7309, sc-13572, sc-5523, SC-9154, sc-21772, and sc-7641, respectively), and JC63.1, FA6-152, and anti-CD36 from Abcam (catalog numbers ab23680, ab17044, and ab78054, respectively). In some embodiments, the binding partner is any molecule that specifically binds to CD36 mRNA. As used herein, "specifically binds to CD36 mRNA" means that the molecule is more likely to bind to a portion or the entirety of CD36 mRNA (e.g., by complementary base pairing) than to a portion or the entirety of non-CD36 mRNA or other non-CD36 nucleic acids. In some embodiments, the binding partner that specifically binds to CD36 mRNA is a nucleic acid, such as a probe. The binding partner can be designed using the nucleotide and amino acid sequences of CD36 provided herein. In some embodiments, the CD36 binding partner may include a detectable label, such as an enzymatically active group, a fluorescent molecule, a chromophore, a luminescent molecule, a specifically binding ligand, or a radioisotope. In some embodiments, a second binding partner specific to the CD36 binding partner is also contemplated, such as a secondary antibody.

[0061] sample Aspects of the present disclosure relate to determining the level of CD36 in a sample obtained from a subject. In some embodiments, the sample obtained from the subject is a tumor sample. As used herein, a tumor sample can include, for example, tumor cells, a population of tumor cells, a tumor fragment (e.g., a biopsy), or an entire tumor. In some embodiments, the tumor sample is a tumor biopsy. In some embodiments, the tumor sample includes circulating tumor cells. In some embodiments, the tumor sample includes ascites fluid. In some embodiments, the tumor sample includes pleural effusion. The tumor sample may include non-tumor cells or non-tumor tissue (e.g., a biopsy including normal tissue surrounding a tumor fragment). In some embodiments, the sample may be a tissue or body fluid sample obtained from the subject. Examples of body fluid samples include blood, plasma, serum, and urine.

[0062] subject Aspects of the present disclosure relate to a subject, such as a human, having cancer. Any type of cancer is contemplated herein, including, but not limited to, leukemia, lymphoma, myeloma, carcinoma, metastatic cancer, sarcoma, adenoma, cancer of the nervous system, and genitourinary cancer. Exemplary cancer types are: adult and pediatric acute lymphocytic leukemia, acute myeloid leukemia, adrenocortical carcinoma, AIDS-related cancer, anal cancer, appendix cancer, astrocytoma, basal cell carcinoma, bile duct cancer, bladder cancer, bone cancer, osteosarcoma, fibrohistiocytoma, brain cancer, brain stem glioma, cerebellar astrocytoma, malignant glioma, ependymoma, medulloblastoma, supratentorial primitive neuroectodermal tumor, hypothalamic glioma, breast cancer, male breast cancer, bronchial adenoma, Burkitt lymphoma, carcinoid tumor, cancer of unknown cause, central nervous system lymphoma, cerebellar astrocytoma, malignant glioma, cervical cancer, childhood cancer, chronic lymphocytic leukemia, chronic myeloid leukemia, chronic myeloproliferative disorders, colorectal cancer, cutaneous T-cell lymphoma, endometrial cancer, ependymoma, esophageal cancer, Ewing family tumors, extracranial germ cell tumors, extragonadal germ cell tumors, extrahepatic bile duct cancer, intraocular melanoma, retinoblastoma, gallbladder cancer, gastric cancer, gastrointestinal stromal tumors, extracranial germ cell tumors, extragonadal germ cell tumors, ovarian germ cell tumors, gestational trophoblastic tumors, glioma, hairy cell leukemia, head and neck cancer, hepatocellular carcinoma, Hodgkin lymphoma, non-Hodgkin lymphoma, hypopharyngeal cancer, hypothalamic and visual pathway glioma, intraocular melanoma, pancreatic islet cell tumor, Kaposi's sarcoma, kidney cancer, renal cell carcinoma, laryngeal cancer, lip and oral cavity cancer, small cell lung cancer,

[0063] Non-small cell lung cancer, primary central nervous system lymphoma, Waldenstrom's macroglobulinemia, malignant fibrous histiocytoma, medulloblastoma, melanoma, Merkel cell carcinoma, malignant mesothelioma, squamous cell neck cancer, multiple endocrine neoplasia syndrome, multiple myeloma, mycosis fungoides, myelodysplastic syndrome, myeloproliferative disorders, chronic myeloproliferative disorders, nasal cavity and paranasal sinus cancer, nasopharyngeal cancer, neuroblastoma, oropharyngeal cancer, ovarian cancer, pancreatic cancer, parathyroid cancer, penile cancer, pharyngeal cancer, pheochromocytoma, pineal somatoblastoma and supratentorial primitive neuroectodermal tumor, pituitary cancer, plasma cell neoplasm, pleuropulmonary blastoma, prostate cancer, rectal cancer, rhabdomyosarcoma, salivary gland cancer, soft tissue sarcoma, uterine sarcoma, Sézary syndrome, non-melanoma skin cancer, small intestine cancer, squamous cell carcinoma, squamous cell cervical carcinoma, supratentorial primitive neuroectodermal tumor, testicular cancer, pharyngeal cancer, thymoma and thymic carcinoma, thyroid cancer, transitional cell carcinoma, trophoblastic tumor, urethral cancer, uterine cancer, uterine sarcoma, vaginal cancer, vulvar cancer, or Wilms tumor. In some embodiments, the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma. In some embodiments, the cancer is prostate cancer, breast cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma. In some embodiments, the cancer is pancreatic cancer, ovarian cancer, breast cancer, prostate cancer, melanoma, or lung cancer.

[0064] Controls and control levels Aspects of the present disclosure relate to the comparison of the CD36 level in a sample with a control level.In some embodiments, the control level is the CD36 level in cells, tissues or body fluids obtained from a healthy subject or a group of healthy subjects.Herein, a healthy subject is a subject that does not have any obvious disease, such as cancer, or has no history of disease. In some embodiments, the control level is determined from a sample obtained from a subject with cancer.Therefore, in some embodiments, the control level is obtained from the same subject as the subject from which the sample is obtained.In some embodiments, the control level is the level of CD36 from non-cancerous cells or tissue obtained from a subject with cancer. In some embodiments, the control level is a CD36 level that is undetectable or below background / noise levels obtained using standard detection methods (eg, Western blot or immunohistochemistry).

[0065] The present disclosure also encompasses comparing the level of CD36 in a sample from a subject to a predetermined level or value, eliminating the need to measure a control level every time. The predetermined level or value can take various forms. It can be a single cutoff value, such as a median or mean. It can be established based on comparison groups, for example, one defined group known to be unresponsive to treatment with Psap peptides and another defined group known to be responsive to treatment with Psap peptides. It can also be a range, for example, by dividing the test population equally (or unevenly) into groups (non-responsive to treatment with Psap peptides, somewhat responsive to treatment with Psap peptides, and highly responsive to treatment with Psap peptides) or into four groups (the lowest group being subjects unresponsive to treatment with Psap peptides and the highest group being subjects most responsive to treatment with Psap peptides). The predetermined value may depend on the particular population selected. For example, an apparently healthy group (without detectable cancer or history of cancer) will have a "normal" range of CD36 that is different from a group of members who have cancer but are known not to respond to treatment with Psap peptides. Thus, the selected predetermined value may take into account the category to which the subject belongs. Appropriate ranges and categories can be selected by those skilled in the art without more than routine experimentation.

[0066] example Example 1 method Cell lines and primary cells The cell line PC3 was previously described (Kang et al. PNAS. 2009; 106:12115-20). PC3 cells were cultured in RPMI containing 10% FBS. The human breast cancer cell lines MDA-MB-231 and MCF-7 were previously described (Ryu et al. PLoS one, 6, 2011). The mouse Lewis lung carcinoma cell line LLC (provided by Lea Eisenbach, Wiesmann Institute of Science, Rehovot, Israel), stably expressing RFP and firefly luciferase (Gupta GP, Massague J. Cancer metastasis: building a framework. Cell. 2006;127:679-95; Gao D, Nolan DJ, Mellick AS, Bambino K, McDonnell K, Mittal V. Endothelial progenitor cells control the angiogenic switch in mouse lung metastasis. Science. 2008;319:195-8; and Joyce JA, Pollard JW. Microenvironmental regulation of metastasis. Nat Rev Cancer. 2009;9:239-52), was cultured in DMEM supplemented with 10% fetal bovine serum.B16 melanoma cells, LNCaP prostate cancer cells, AsPc1 pancreatic cancer cells, and ID8 ovarian cancer cells have been previously described (Overwijk WW et al. B16 as a mouse model for human melanoma. Curr Protoc Immunol. 2001, May; Chapter 20: Unit 20.1; Horoszewicz JS, Leong SS, Kawinski E et al. LNCaP model of human prostatic carcinoma. Cancer Res. 1983, Apr; 43(4): 1809-18.; Chen WH, et al. Human pancreatic adenocarcinoma: in vitro and in vivo morphology of a new tumor line established from ascites. In Vitro 18: 24-34, 1982; and Roby KF, et al. Development of a syngeneic mouse model for events related to ovarian cancer. Carcinogenesis. 2000, 21:585-591). Primary ovarian cancer cells were obtained from the ascites of an ovarian cancer patient.

[0067] Western blot analysis Cells were homogenized in lysis buffer (BioRad) containing protease inhibitors (Roche Applied Science). Samples were boiled in 1x SDS sampling buffer and loaded onto a 4-20% gradient Bis-Tris NuPAGE gel (Invitrogen). Western blotting was performed using antibodies specific for CD36 (AbCam, ab78054) or β-actin (Sigma-Aldrich).

[0068] In vitro cell proliferation assay Cell proliferation was measured using an MTT (3-{4,5-dimethylthiazol-2-yl}-2,5-diphenyltetrazolium bromide, Sigma-Aldrich) assay. Cells were seeded in 50 μL of growth medium in 96-well culture plates and allowed to attach overnight. 50 μL of growth medium plus 2x concentrated treatment reagent was then added. After each treatment time point, 10 μL of 5% MTT solution (buffered in PBS) was added to each well. The plates were incubated at 37°C for an additional 4 hours to allow MTT to be metabolically converted to formazan crystals in the mitochondria of the cells. The formazan crystals were finally solubilized by adding 100 μL of 10% sodium dodecyl sulfate in 50% N-dimethylformamide to each microplate well. The absorbance at 550 and 680 nm (corresponding to the formazan salt and reference wavelengths, respectively) was measured using a colorimetric microplate reader. Wells containing complete medium alone served as controls. Each experiment was performed twice, with six replicates for each drug concentration.

[0069] result We hypothesized that Tsp-1, upregulated by Psap peptide, may act directly on cancer cells, not just indirectly through an antiangiogenic mechanism. To test this, LLC cells were treated with either recombinant Tsp-1 or DWLPK (SEQ ID NO: 2) Psap peptide, and cell proliferation was measured using an MTT assay. We found that Tsp-1 reduced cell proliferation, whereas Psap peptide had no effect (Figure 1A). This supports the hypothesis that Tsp-1 can directly act on cancer cells, since this assay was performed in vitro in the absence of any blood vessels. These results also show that Psap peptide alone does not appear to affect cancer cell proliferation, supporting the hypothesis that Psap peptide can indirectly treat cancer through upregulation of Tsp-1. LLC cells have been shown to express CD36, the receptor for Tsp-1, indicating that Tsp-1 may directly act on cancer cells via CD36 (Figure 1B).

[0070] CD36 levels were measured in other cell lines to determine whether CD36 was also expressed by other cancer types. CD36 levels were measured by Western blot analysis in breast cancer (MDA-231, MCF-7), ovarian cancer (ID8), melanoma (B16), prostate cancer (PC3 and LNCaP), and lung cancer (LLC) cell lines. CD36 protein was detected in all cell lines tested, with particularly high levels of CD36 detected in MDA-231, MCF-7, PC3, and LLC cell lines (Figure 2). MDA-231, ID8, B16, PC3, and LLC cells have previously been shown to respond to treatment with Psap peptide in vivo. The pancreatic cell line AsPc1 was also examined and found to express CD36. CD36 levels were also measured in primary ovarian cancer cells derived from patients with ascites. CD36 protein was detectable in all primary ovarian cancer cells tested (Figure 3).

[0071] Example 2 method Mice and cell lines All animal work was performed in accordance with protocols approved by the Institutional Animal Care and Use Committee. Wild-type C57BL / 6J and GFP transgenic C57BL / 6-Tg(ACTB-EGFP)1Osb / J mice were obtained from The Jackson Laboratory (Bar Harbor, Maine). CB-17 SCID mice were obtained from Charles River (Wilmington, MA). The cell lines PC3 and PC3M-LN4 have been previously described (14). The human breast cancer cell lines MDA-MB-231 and MDA-MB-LM2 have been previously described (Ryu et al. PLoS one, 6, 2011). The mouse Lewis lung carcinoma cell line LLC / D122 (provided by Lea Eisenbach, Wiesmann Institute of Science, Rehovot, Israel), which stably expresses RFP and firefly luciferase (Gupta GP, Massague J. Cancer metastasis: building a framework. Cell. 2006;127:679-95; Gao D, Nolan DJ, Mellick AS, Bambino K, McDonnell K, Mittal V. Endothelial progenitor cells control the angiogenic switch in mouse lung metastasis. Science. 2008;319:195-8; and Joyce JA, Pollard JW. Microenvironmental regulation of metastasis. Nat Rev Cancer. 2009;9:239-52), was cultured in DMEM supplemented with 10% fetal bovine serum.

[0072] Tissue microarray and immunohistochemistry Archival specimens (radical prostatectomy specimens or metastatic biopsies) were obtained from the files of the Department of Pathology, The Gade Institute, Haukeland University Hospital. Formalin-fixed prostatectomy specimens were embedded in paraffin and examined by whole-mount step sectioning at 5 mm intervals. Tissue microarrays (TMAs) were constructed by selecting three tissue cores (0.6 mm diameter) from the area of ​​the highest tumor grade in each case. Thin paraffin sections (5 μm) from TMA paraffin blocks were dewaxed with xylene / ethanol, followed by heat-induced microwave epitope retrieval in citrate buffer (pH 6.0) for 20 minutes and incubation with CD36 antibody for 60 minutes at room temperature. Immunostaining was performed on a DAKO Autostainer (Dako Cytomation, Copenhagen, Denmark) using the EnVision chain polymer method as the detection system. Antigen localization was achieved using the DAB-diaminobenzidine peroxidase reaction and counterstaining with hematoxylin. Immunostaining was estimated semiquantitatively by calculating the staining index (SI), which is the product of staining intensity (0–3) and the percentage of immunopositive tumor cells (<10% = 1, 10–50% = 2, >50% = 3). The staining index (ranging from 0–9) is a categorical scale, with some variation expected within each category.

[0073] Knockdown of CD36 in tumor cells CD36 levels are reduced in cancer cell lines using retroviral or lentiviral vectors encoding miRNAs or shRNAs targeting CD36. Knockdown efficiency is tested using qPCR analysis. Total RNA is extracted using the PicoPure RNA Extraction Kit (Arcturus) according to the manufacturer's protocol. RNA is converted to cDNA using qScript® cDNA Supermix (Quanta Biosciences). qPCR is performed using primers and iQ™ SYBER Green Master Mix (Biorad, Hercule, CA). A standard protocol, initial denaturation at 95°C for 10 minutes, followed by 40 cycles of 95°C for 10 seconds, 60°C for 30 seconds, and 72°C for 30 seconds, followed by a final extension at 72°C for 5 minutes, and melting curve analysis, is performed using a BioRad CFX96 Real Time System (BioRad) combined with BioRad-CFX Manager software. The relative abundance of each transcript compared to the control is calculated using the delta Ct method.

[0074] In vitro cell proliferation assay Cell proliferation was measured using an MTT (3-{4,5-dimethylthiazol-2-yl}-2,5-diphenyltetrazolium bromide, Sigma-Aldrich) assay. Cells were seeded in 50 μL of growth medium in 96-well culture plates and allowed to attach overnight. 50 μL of growth medium plus 2x concentrated treatment reagent was then added. After each treatment time point, 10 μL of 5% MTT solution (buffered in PBS) was added to each well. The plates were incubated at 37°C for an additional 4 hours to allow MTT to be metabolically converted to formazan crystals in the mitochondria of the cells. The formazan crystals were finally solubilized by adding 100 μL of 10% sodium dodecyl sulfate in 50% N-dimethylformamide to each microplate well. The absorbance at 550 and 680 nm (corresponding to the formazan salt and reference wavelengths, respectively) was measured using a colorimetric microplate reader. Wells containing complete medium alone served as controls. Each experiment was performed twice, with six replicates for each drug concentration.

[0075] Metastasis assay, bioluminescence imaging and analysis For experimental metastasis, 7-week-old C57BL / 6 mice were inoculated with 1 × 10 5 Inject 5 x 10 luciferase-labeled LLC cells via the tail vein. For orthotopic breast cancer cell injection, inject 5 x 10 6 MDA-MB-231 or its metastatic variant MDA-MB-LM2 cells were injected into the fat pad of CB-17 SCID mice in a volume of 0.1 ml. Tumor growth and lung metastasis (after resection of the primary tumor) were monitored weekly by live animal bioluminescence imaging (Xenogen). For orthotopic prostate cancer cell injection, 2 × 10 cells were injected. 6 Live LN4 or cells were injected into the prostate of mice. To determine metastatic burden in vivo, mice were anesthetized and injected intraperitoneally with 75 mg / kg D-luciferin (100 μL of 30 mg / mL in PBS). Metastatic growth was monitored over time using bioluminescence imaging, which was performed on a Xenogen IVIS system incorporating Living Image acquisition and analysis software (Xenogen), with mice placed in a supine position for 5 minutes after D-luciferin injection. For BLI plots, photon flux for each mouse was calculated using the same circular region of interest surrounding the mouse's chest.

[0076] Psap peptide administration Eight-week-old mice are treated with Psap peptides (e.g., DWLPK (SEQ ID NO: 2), DWLP (SEQ ID NO: 3), or modifications thereof) diluted in PBS via intraperitoneal injection at a dose of 30 mg / kg / day for up to two weeks.

[0077] result CD36 levels are measured in tissue samples from human subjects with cancer. CD36 levels were knocked down in cancer cell lines, and these cell lines with reduced CD36 were injected into mice. The mice were then administered Psap peptide. Tumor growth and metastatic burden were monitored. Knocking down CD36 in cancer cells is expected to reduce the anti-cancer activity of Psap peptide in vivo.

[0078] Example 3 method Except where otherwise noted, the methods used in Example 3 were identical to those used in Examples 1 and 2. The cell lines tested for CD36 expression were pancreatic cancer (AsPC1), ovarian cancer (DF-14 and ID-8), breast cancer (MDA-MB231 and LM2), prostate cancer (PC3, PC3-M-LN4, LN-CAP, and LN-CAP-LN3), melanoma (B16-BL6), and lung cancer (LLC) cell lines. All of these cell lines are known in the art and / or commercially available. CD36-expressing ovarian cancer cells were treated with either control or thrombospondin (Tsp-1, 100 ng, 500 ng, or 1000 ng), and the percentage of surviving cells was determined at 0 or 48 hours.

[0079] In a mouse model of ovarian cancer, one million luciferase-expressing ovarian cancer cells were injected intraperitoneally. Treatment began 17 days later with cisplatin (4 mg / kg QOD), Psap peptide dWlP (SEQ ID NO: 47, 40 mg / kg QD), a combination of cisplatin and Psap peptide, or PBS QD. Luciferase intensity was measured over several days, beginning around day 17. In a mouse model of pancreatic cancer, 1 × 10 6 AsPc1 human pancreatic cells were injected into the pancreas of SCID mice. Mice were treated with either control or Psap peptide dWlP (SEQ ID NO: 47, 20 mg / kg / day or 40 mg / kg / day). Treatment began on day 25 and continued daily for 21 days. Mice were then euthanized, and the primary tumor mass was measured. The presence or absence of ascites was also measured. For the melanoma mouse model, mice were injected with B16-BL6 cells. Mice were treated with either the Psap peptide dWlP (SEQ ID NO: 47, 10 or 40 mg / kg) or a control. Tumor volume was measured over time up to approximately 20-25 days after cell injection.

[0080] result Multiple cancer cell lines were tested for CD36 expression, and CD36 protein was detected in all cell lines tested, with particularly high levels found in AsPC1, DF-14, MDA-MB231, and PC3 cell lines (Figure 5). CD36-expressing ovarian cells were shown to be susceptible to Tsp-1-mediated cell killing in a dose-dependent manner (Fig. 6 ). Two "high" CD36 cell lines (ovarian cancer cells and AsPC pancreatic cancer cells) and one "low" CD36 cell line (B16-B6 cancer cells) were injected into mice to test the effect of Psap peptide on tumor growth and metastasis. The "high" CD36 cancer model was found to regress in response to treatment with Psap peptide (Figures 5 and 7). The ovarian cancer model also showed regression of metastatic disease (Figure 5). The pancreatic cancer model also showed inhibition of metastasis, as only 1 of 19 mice treated with Psap peptide developed ascites, while 4 of 10 mice treated with the control developed ascites. In a "low" CD36 melanoma model, treatment with Psap peptide was found to inhibit primary tumor growth but not cause tumor regression (Figure 8). These results indicate that "high" CD36 cancers may respond more strongly to Psap peptide treatment (e.g., regression of primary tumors and / or metastases), while "low" CD36 cancers may respond less strongly (e.g., inhibition rather than regression of primary tumors).

[0081] Without further elaboration, it is believed that one skilled in the art can, based on the preceding description, utilize the present disclosure to its fullest extent. The specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way. All publications cited herein are incorporated by reference for the purpose or subject matter referenced herein. As used herein in the specification and claims, the indefinite articles "a" and "an" should be understood to mean "at least one," unless expressly stated otherwise. From the above description, those skilled in the art can easily ascertain the essential features of the present disclosure, and can make various changes and modifications to the present disclosure to adapt it to various uses and conditions without departing from the spirit and scope thereof. Accordingly, other embodiments are also within the scope of the claims.

Claims

1. 1. A method for assessing a subject's responsiveness to treatment with a Psap peptide, the method comprising: The method includes determining the level of CD36 in a sample obtained from a subject having cancer, wherein an elevated level of CD36 in the sample compared to the control level indicates that the subject is responsive or likely to respond to treatment with a Psap peptide.

2. The method of claim 1, wherein the level of CD36 in the sample is determined by performing an assay.

3. The method further The method of claim 1 or 2, comprising identifying a subject having an elevated level of CD36 in the sample compared to a control level as being responsive or likely to be responsive to treatment with a Psap peptide.

4. The method further The method of claim 3, comprising administering an effective amount of a Psap peptide to a subject identified as being responsive or likely to be responsive to treatment with a Psap peptide for treating cancer.

5. 1. A method for treating a subject having cancer, comprising: The method comprises administering to a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level an effective amount of a Psap peptide for treating the cancer.

6. 1. A method for treating a subject having cancer, comprising: (a) selecting a subject with cancer based on the subject being known to have an elevated level of CD36 in a sample compared to a control level; (b) administering to the subject an effective amount of a Psap peptide, such that the subject has an elevated level of CD36 in the sample compared to the control level; The method comprising:

7. The method of any one of claims 1 to 6, wherein the control level is the level of CD36 from a non-cancerous cell or tissue obtained from a subject with cancer.

8. The method of any one of claims 1 to 6, wherein the control level is the level of CD36 in a cell or tissue obtained from a healthy subject or a population of healthy subjects.

9. The method of any one of claims 1 to 6, wherein the control level is a predetermined level.

10. The method of any one of claims 1 to 9, wherein the level of CD36 is a CD36 protein level.

11. The method of any one of claims 1 to 10, wherein the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma.

12. The Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or an amino acid substitution variant thereof, wherein the amino acid substitution is: a) tyrosine (Y) to tryptophan (W); b) an amino acid substitution selected from valine (V), alanine (A) or glycine (G), or a non-standard amino acid of similar size, or a derivative thereof, for leucine (L); c) arginine (R) to lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L); e) the D-isomer of tryptophan (W) relative to the L-isomer of tryptophan (W), and / or the D-isomer of proline (P) relative to the L-isomer of proline (P); or combinations thereof; The method according to any one of claims 1 to 11, wherein

13. 13. The method of claim 12, wherein the Psap peptide is 50 amino acids or less in length.

14. 14. The method of claim 13, wherein the Psap peptide is 30 amino acids or less in length.

15. 15. The method of claim 14, wherein the Psap peptide is 15 amino acids or less in length.

16. 16. The method of claim 15, wherein the Psap peptide is six amino acids or less in length.

17. 13. The method of claim 12, wherein the Psap peptide is a cyclic peptide.

18. 18. The method of any one of claims 12 to 17, wherein the non-standard amino acid of similar size is methylvaline, methylleucine, or sarcosine.

19. A composition comprising a Psap peptide for use in treating a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level.

20. Use of a composition in the manufacture of a medicament for treating a subject having cancer and characterized by an elevated level of CD36 in the sample compared to a control level, wherein the composition contains a Psap peptide.

21. 21. The composition or use of claim 19 or 20, wherein the control level is the level of CD36 from non-cancerous cells or tissue obtained from a subject with cancer.

22. 21. The composition or use of claim 19 or 20, wherein the control level is the level of CD36 in cells or tissue obtained from a healthy subject or a population of healthy subjects.

23. 21. The composition or use of claim 19 or 20, wherein the control level is a predetermined level.

24. The composition or use according to any one of claims 19 to 23, wherein the level of CD36 is the CD36 protein level.

25. The composition or use of any one of claims 19 to 24, wherein the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma.

26. The Psap peptide comprises the amino acid sequence CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), or DWLP (SEQ ID NO: 3), or an amino acid substitution variant thereof, wherein the amino acid substitution is: a) tyrosine (Y) to tryptophan (W); b) an amino acid substitution selected from valine (V), alanine (A) or glycine (G), or a non-standard amino acid of similar size, or a derivative thereof, for leucine (L); c) arginine (R) to lysine (K); d) the D isomer of aspartic acid (D) versus the L isomer of aspartic acid (D), and / or the D isomer of leucine (L) versus the L isomer of leucine (L); e) the D-isomer of tryptophan (W) relative to the L-isomer of tryptophan (W), and / or the D-isomer of proline (P) relative to the L-isomer of proline (P); or combinations thereof; The composition or use according to any one of claims 19 to 25, wherein

27. 27. The composition or use of claim 26, wherein the Psap peptide is 50 amino acids or less in length.

28. 28. The composition or use of claim 27, wherein the Psap peptide is 30 amino acids or less in length.

29. 29. The composition or use of claim 28, wherein the Psap peptide is 15 amino acids or less in length.

30. 30. The composition or use of claim 29, wherein the Psap peptide is 6 amino acids or less in length.

31. 27. The composition or use of claim 26, wherein the Psap peptide is a cyclic peptide.

32. 32. The composition or use of any one of claims 26 to 31, wherein the non-standard amino acid of similar size is methylvaline, methylleucine, or sarcosine.

33. 33. The method, use or composition of any one of claims 1 to 32, wherein the sample is a tumor sample.

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