Treating cancer
Provided is a cyclic peptide which comprises: (i) a CDK4 peptide region; and (ii) a cell-penetrating region; wherein the CDK4 peptide region comprises the amino acid sequence P 1 R 1 x 1 y 1 R 2 P 2 V (SEQ ID NO: 1), in which P 1 and P 2 are each proline, R 1 and R 2 are each arginine and each of x 1 and y 1 are either a linker or proline, wherein if x 1 is a linker then y 1 is proline or if x 1 is proline then y 1 is a linker, or wherein x 1 and y 1 when taken together form a linker, and wherein V may be present or absent; and wherein the cell-penetrating region is capable of enhancing the uptake of the cyclic peptide or a part thereof into cancer cells and comprises an amphiphilic amino acid sequence; and wherein the cyclic peptide or a part thereof is cytotoxic to and/or inhibiting to the growth of a cancer cell.
1. A cyclic peptide which comprises:
(i) a CDK4 peptide region; and
(ii) a cell-penetrating region;
wherein the CDK4 peptide region comprises the amino acid sequence P 1 R 1 x 1 y 1 R 2 P 2 V (SEQ ID NO: 1), in which P 1 and P 2 are each proline, R 1 and R 2 are each arginine and each of x 1 and y 1 are either a linker or proline, wherein if x 1 is a linker then y 1 is proline or if x 1 is proline then y 1 is a linker, or wherein x 1 and y 1 when taken together form a linker, and wherein V may be present or absent; wherein each amino acid is the L stereoisomer or wherein the valine residue of the amino acid sequence P 1 R 1 x 1 y 1 R 2 P 2 V (SEQ ID NO: 1) of the CDK4 peptide region is the D stereoisomer and all other amino acids in the cyclic peptide are the L stereoisomer; and
wherein the cell-penetrating region is capable of enhancing the uptake of the cyclic peptide or a part thereof into cancer cells and comprises an amphiphilic amino acid sequence; and wherein the cyclic peptide or a part thereof is cytotoxic to and/or inhibiting to the growth of a cancer cell.
2. A cyclic peptide according to claim 1 wherein the cell-penetrating region is capable of enhancing the uptake of the CDK4 peptide region.
3. A peptide according to claim 1 wherein the linker comprises C 1 to C 4 hydrocarbylene or an amino acid.
4. A peptide according to claim 1 , wherein the linker is glycine.
5. A peptide according to claim 4 wherein x 1 is glycine and y 1 is proline.
6. A peptide according to claim 1 , wherein the amphiphilic amino acid sequence is 9 or 10 amino acids in length.
7. A peptide according to claim 1 , wherein the amphiphilic amino acid sequence comprises ALKLALK (SEQ ID NO: 5).
8. A peptide according to claim 1 , wherein the amphiphilic amino acid sequence comprises ALKLALKLAL (SEQ ID NO: 7).
9. A peptide according to claim 1 , wherein the amphiphilic amino acid sequence is 9 amino acids in length, and wherein the cyclic peptide further comprises a dipeptide spacer between the CDK4 peptide region and the cell-penetrating region.
10. A peptide according to claim 9 , wherein the amphiphilic amino acid sequence comprises KLALKLALK (SEQ ID NO: 8).
11. A peptide according to claim 9 wherein the dipeptide spacer is FP, such that the CDK4 peptide and the dipeptide spacer together have the sequence FPP 1 R 1 x 1 y 1 R 2 P 2 V (SEQ ID NO:46).
12. A peptide according to claim 1 , wherein the amphiphilic amino acid sequence comprises ALRLALRLAL (SEQ ID NO:41).
13. A peptide according to claim 4 in which a glycine or arginine residue in the amino acid sequence P 1 R 1 x 1 y 1 R 2 P 2 V (SEQ ID NO:1) is methylated on the backbone amide nitrogen.
14. A peptide according to claim 13 wherein R 1 or R 2 is methylated on the backbone amide nitrogen.
15. A peptide according to claim 13 wherein x 1 is glycine which is methylated on the backbone amide nitrogen.
16. A peptide according to claim 1 , wherein each amino acid is the L stereoisomer.
17. A peptide according to claim 1 , wherein the valine residue of the amino acid sequence P 1 R 1 x 1 y 1 R 2 P 2 V of the CDK4 peptide region is the D stereoisomer.
18. A peptide according to claim 1 which is selected from the group consisting of:
cyc-[PRGPRPVALKLALKLAL],
cyc-[P(N-Me-Arg)GPRPVALKLALKLAL],
cyc-[PR(N-Me-Gly)PRPVALKLALKLAL],
cyc-[PRGP(N-Me-Arg)PVALKLALKLAL],
cyc-[PRGPRPVALRLALRLAL],
cyc-[PRGPRPALKLALKLAL];
and
cyc-[PRGPRPVKLALKLALKFP].
19. A cyclic peptide which comprises
(i) a CDK4 peptide region; and
(ii) a cell-penetrating region;
wherein the CDK4 peptide region comprises the amino acid sequence FXXRZXRY (SEQ ID NO: 19), in which F is phenylalanine, R is arginine, Z is a linker, X and Y are proline or threonine, Y may be present or absent and at least one of X and/or Y is proline; and residues 1 and 2 of SEQ ID NO:19 may both be present or both be absent; wherein each amino acid is the L stereoisomer; and
wherein the cell-penetrating region comprises a moiety capable of enhancing the uptake of the CDK4 peptide region into cancer cells and wherein the cell-penetrating region is an amphiphilic region; and wherein the cyclic peptide is cytotoxic to and/or inhibiting to the growth of a cancer cell.
20. A peptide according to claim 19 , wherein Y is present in the CDK4 peptide region.
21. A peptide according to claim 19 , wherein X and Y are proline.
22. A peptide according to claim 19 , wherein the linker comprises C 1 to C 4 hydrocarbylene or a non-polar amino acid.
23. A peptide according to claim 19 , wherein the linker is glycine.
24. A peptide according to claim 19 , which further comprises V attached to the C terminal end of the CDK4 peptide region.
25. A peptide according to claim 19 , wherein the cell-penetrating region comprises a peptide.
26. A peptide according to claim 19 wherein the amphiphilic region comprises KLALKLALK (SEQ ID NO: 8).
27. A peptide according to claim 19 , wherein the peptide is non-inhibitory to a non-cancerous cell and/or a control cell.
28. A pharmaceutical composition comprising the peptide of claim 1 , and a pharmaceutical carrier, diluent or excipient.
29. A pharmaceutical composition according to claim 28 , further comprising a p53 inhibitor.
30. A pharmaceutical composition according to claim 29 , wherein said p53 inhibitor is pifithrin-α.
31. A method of manufacturing a pharmaceutical composition, comprising:
a) providing a peptide as defined in claim 1 ;
b) optionally providing a p53 inhibitor;
c) manufacturing a pharmaceutical composition comprising said peptide and optionally, said p53 inhibitor.
32. A method of treating cancer in a subject comprising contacting the subject with a peptide according to claim 1 .
33. A method of treating cancer in a subject comprising contacting the subject with a peptide according to claim 1 , and a p53 inhibitor as a combined preparation for simultaneous, separate or sequential use in the treatment of a cancer containing cells that express wild type p53.
34. The method of claim 32 , wherein the cancer is selected from the group consisting of: breast cancer, prostate cancer, colorectal cancer, bladder cancer, ovarian cancer, endometrial cancer, cervical cancer, head and neck cancer, stomach cancer, pancreatic cancer, esophageal cancer, small cell lung cancer, non-small cell lung cancer, malignant melanoma, neuroblastoma, leukaemia, lymphoma, sarcoma and glioma.
35. A pharmaceutical composition according to claim 28 , further comprising stem cells.