Use of CD36 to identify cancer subjects for treatment
Provided herein are methods for identifying a subject with cancer for treatment with a Psap peptides. The subject is identified based on a level of CD36. Also provided herein are compositions and methods for treatment of a subject with cancer based on a level of CD36.
1. A method for treating cancer in a subject in need thereof, the method comprising: administering to the subject an effective amount of a prosaposin (Psap) peptide, wherein the cancer is characterized by an elevated level of CD36 as compared to a control level of CD36, and wherein the Psap peptide is 4 to 9 amino acids in length and comprises an amino acid sequence selected from the group consisting of CDWLPK (SEQ ID NO: 1), DWLPK (SEQ ID NO: 2), DWLP (SEQ ID NO: 3), and amino acid substitution variants thereof, wherein the amino acid substitution variant comprises an amino acid substitution selected from the group consisting of:
a) Tyrosine (Y) for Tryptophan (W);
b) an amino acid substitution for Leucine (L) selected from Valine (V), Alanine (A) or Glycine (G), or a non-canonical amino acid selected from the group consisting of methylvaline, methylleucine, or sarcosine;
c) Arginine (R) for Lysine (K);
d) a D-isomer of Aspartic Acid (D) for an L-isomer of Aspartic Acid (D) and/or a D-isomer of Leucine (L) for a L-isomer of Leucine (L); and
e) a D-isomer of Tryptophan (W) for an L-isomer of Tryptophan (W) and/or a D-isomer of Proline (P) for an L-isomer of Proline (P).
2. The method of claim 1 , wherein the control level is a level of CD36 from a non-cancerous cell or tissue obtained from the subject having the cancer.
3. The method of claim 1 , wherein the control level is a level of CD36 in a cell or tissue obtained from a healthy subject or a population of healthy subjects.
4. The method of claim 1 , wherein the control level is a predetermined level.
5. The method of claim 1 , wherein the level of CD36 is a CD36 protein level.
6. The method of claim 1 , wherein the cancer is prostate cancer, breast cancer, ovarian cancer, lung cancer, leukemia, pancreatic cancer, glioblastoma multiforme, astrocytoma, or melanoma.
7. The method of claim 1 , wherein the Psap peptide is a cyclic peptide.
8. The method of claim 1 , wherein the control level is a level of CD36 from a non-cancerous cell or tissue obtained from the subject having the cancer.
9. The method of claim 1 , wherein the Psap peptide comprises one or more modifications selected from the group consisting of acetylation, pegylation, and conjugation to a polymer that enhances serum half-life of the peptide.
10. The method of claim 1 , wherein the Psap peptide is a dimer, trimer, or multimer.
11. The method of claim 1 , wherein the Psap peptide is 6 or fewer amino acids in length.