IL-13 receptor binding peptides

1. A targeting peptide that specifically binds to an IL13 receptor, wherein said targeting peptide is not an IL13 fragment, said peptide having a structure of FORMULA I: (SEQ ID NO:5)

X—R 1 —R 2 —R 3 —R 4 —R 5 —R 6 —R 7 —Y  (I)

wherein:

R 1 is G or S;

R 2 is E or D;

R 3 is M or W;

R 4 is G, S or A;

R 5 is W, F, H or Y;

R 6 is V, P, T or N;

R 7 is R, K or H; and

X and Y can each independently be present or absent and when present can each independently be a capping group, a linking group, an amino acid optionally terminated by a capping group or linking group, or a peptide consisting of from 2 to 10 additional amino acids optionally terminated by a capping group or linking group.

2. The peptide of claim 1 , wherein said peptide specifically binds to the IL13Rα2 protein.

3. The peptide of claim 1 , wherein said peptide does not specifically bind to the IL-13Rα1 protein.

4. The peptide of claim 1 , wherein said peptide does not bind to the binding site for IL-13 on the IL13Rα2 protein (or does not competitively inhibit IL-13 binding to the IL13Rα2 protein).

5. The peptide of claim 1 , wherein said peptide is from 7 to 15 amino acids in length.

6. The peptide of claim 1 , wherein said peptide is selected from the group consisting of:

CGEMGWVRC (SEQ ID NO:60); and

ACGEMGWVRCGGGS (SEQ ID NO:65).

7. A targeting peptide that specifically binds to an IL13 receptor, wherein said targeting peptide is not an IL13 fragment, said peptide having a structure of FORMULA II (SEQ ID NO:6):

X—R 1 —R 2 —R 3 —R 4 —R 5 —R 6 —R 7 —Y  (II)

wherein:

R 1 through R 7 is selected from the group consisting of:

APQLWLF,

(SEQ ID NO: 82)

IPQLWLF,

(SEQ ID NO: 83)

VPQLWLF,

(SEQ ID NO: 84)

MPQLWLF,

(SEQ ID NO: 85)

LVQLWLF,

(SEQ ID NO: 86)

LTQLWLF,

(SEQ ID NO: 87)

LNQLWLF

(SEQ ID NO: 88)

LPNLWLF,

(SEQ ID NO: 89)

LPDLWLF,

(SEQ ID NO: 90)

LPELWLF,

(SEQ ID NO: 91)

LPHLWLF,

(SEQ ID NO: 92)

LPQAFAW,

(SEQ ID NO: 93)

LPQIFIH,

(SEQ ID NO: 94)

LPQVHVY,

(SEQ ID NO: 95)

LPQMYMY,

(SEQ ID NO: 96)

MNHMYMY,

(SEQ ID NO: 97)

and

VTEVHVH;

(SEQ ID NO: 98)

and

X and Y can each independently be present or absent and when present can each independently be a capping group, a linking group, an amino acid optionally terminated by a capping group or linking group, or a peptide consisting of from 2 to 10 additional amino acids optionally terminated by a capping group or linking group.

8. A targeting peptide that specifically binds to an IL13 receptor, wherein said targeting peptide is not an IL13 fragment, said peptide having a structure of FORMULA III (SEQ ID NO:7):

X—R 1 —R 2 —R 3 —R 4 —R 5 —R 6 —R 7 —Y  (III)

wherein:

R 1 through R 7 is selected from the group consisting of

GPFLHLL,

(SEQ ID NO: 99)

SVFLHLL,

(SEQ ID NO: 100)

STFLHLL,

(SEQ ID NO: 101)

SNWLHLL,

(SEQ ID NO: 102)

SPHLHLL,

(SEQ ID NO: 103)

SPYLHLL,

(SEQ ID NO: 104)

SPFAHLL,

(SEQ ID NO: 105)

SPFIHLL,

(SEQ ID NO: 106)

SPFVHLL,

(SEQ ID NO: 107)

SPFMHLL,

(SEQ ID NO: 108)

SPFLWLL,

(SEQ ID NO: 109)

SPFLFAA,

(SEQ ID NO: 110)

SPFLFII,

(SEQ ID NO: 111)

SPFLHVV,

(SEQ ID NO: 112)

SPFLYMM,

(SEQ ID NO: 113)

GNYMYMM,

(SEQ ID NO: 114)

and

GTHVFVI;

(SEQ ID NO: 115)

and

X and Y can each independently be present or absent and when present can each independently be a capping group, a linking group, an amino acid optionally terminated by a capping group or linking group, or a peptide consisting of from 2 to 10 additional amino acids optionally terminated by a capping group or linking group.

9. The peptide of claim 1 , wherein said peptide is conjugated to at least one effector molecule.

10. The peptide of claim 9 , wherein said at least one effector molecule consists of one effector molecule.

11. The peptide of claim 9 , wherein said at least one effector molecule consists of two effector molecules.

12. The peptide of claim 11 , wherein said peptide has the structure A-B-C, wherein:

A is said targeting peptide;

B is a first effector molecule; and

C is a second effector molecule.

13. The peptide of claim 12 , wherein B is a toxin and C is an amphipathic antimicrobial peptide.

14. The peptide of claim 13 , wherein said toxin is selected from the group consisting of diphtheria toxin and Pseudomonas exotoxin.

15. The peptide of claim 13 , wherein said amphipathic antimicrobial peptide comprises a sequence selected from the group consisting of: (KLAKLAK) 2 , SEQ ID NO:1; (KLAKKLA) 2 , SEQ ID NO:2; (KAAKKAA) 2 , SEQ ID NO:3; and (KLGKKLG) 2 , SEQ ID NO:4.

16. The peptide of claim 13 , wherein said at least one effector molecule comprises a therapeutic agent, a detectable group, a lipid, or a liposome.

17. An expression vector comprising a nucleic acid that encodes a targeting peptide that specifically binds to an IL13 receptor, wherein said targeting peptide is not an IL13 fragment, said peptide having a structure of FORMULA I: (SEQ ID NO:5)

X—R 1 —R 2 —R 3 —R 4 —R 5 —R 6 —R 7 —Y  (I)

wherein:

R 1 is G or S;

R 2 is E or D;

R 3 is M or W;

R 4 is G, S or A;

R 5 is W, F, H or Y;

R 6 is V, P, T or N;

R 7 is R, K or H; and

X and Y can each independently be present or absent and when present can each independently be an amino acid or a peptide consisting of from 2 to 10 additional amino acids.

18. A host cell that contains the nucleic acid of claim 17 and expresses the encoded peptide.

19. A method of treating cancer in a subject in need thereof, comprising administering said subject a peptide of claim 1 in a treatment effective amount.

20. The method of claim 19 , wherein said cancer is selected from the group consisting of breast cancer, bladder cancer, pancreatic cancer, colorectal cancer, head and neck cancer, thyroid cancer, prostate cancer, and gliomas.

21. The method of claim 19 , wherein said cancer is glioblastoma multiforme.

22. The method of claim 19 , further comprising concurrently administering said subject a second targeting peptide that specifically binds to an IL13 receptor, wherein said second targeting peptide is IL-13, a mutant of IL-13, or an IL-13 receptor binding fragment thereof.

23. A method of delivering at least one effector molecule to a cell of interest, comprising:

contacting the targeting peptide of claim 1 to a cell of interest under conditions in which said targeting peptide is internalized therein, wherein said targeting peptide is coupled to said at least one effector molecule.

24. The method of claim 23 , wherein said at least one effector molecule comprises a detectable group.

25. The peptide of claim 1 , wherein said peptide is selected from the group consisting of:

SEMGWVRC,

(SEQ ID NO: 68)

GDMGWVR,

(SEQ ID NO: 69)

SDWGWVR,

(SEQ ID NO: 70)

SEIGWVR,

(SEQ ID NO: 72)

GEISWVR,

(SEQ ID NO: 73)

GEMAWVR,

(SEQ ID NO: 74)

GEMGFVR,

(SEQ ID NO: 75)

GEMGHVR,

(SEQ ID NO: 76)

GEMSYVR,

(SEQ ID NO: 77)

GEMGWPR,

(SEQ ID NO: 78)

GEMGWTR,

(SEQ ID NO: 79)

GEMGWNK,

(SEQ ID NO: 80)

and

GEMGWNH.

(SEQ ID NO: 81)

26. The peptide of claim 1 , wherein said peptide is ACGEMGWVRCGGGS (SEQ ID NO: 65).

27. The peptide of claim 9 , wherein said at least one effector molecule comprises a therapeutic agent.

28. The peptide of claim 9 , wherein said at least one effector molecule comprises a detectable group.

29. A pharmaceutical formulation comprising the peptide of claim 9 and a pharmaceutical carrier.

30. The method of claim 23 , wherein said cell of interest is a eukaryotic cell.

31. The peptide of claim 7 , wherein said peptide is conjugated to at least one effector molecule.

32. The peptide of claim 31 , wherein said at least one effector molecule comprises a therapeutic agent, a detectable group, a lipid, or a liposome.

33. The peptide of claim 31 , wherein said at least one effector molecule comprises a toxin and/or an amphipathic antimicrobial peptide.

34. A method of delivering at least one effector molecule to a cell of interest, comprising:

contacting the targeting peptide of claim 7 to a cell of interest under conditions in which said targeting peptide is internalized therein, wherein said targeting peptide is coupled to said at least one effector molecule.

35. The method of claim 34 , wherein said at least one effector molecule comprises a therapeutic agent or a detectable group.

36. The method of claim 34 , wherein said cell of interest is a eukaryotic cell.

37. The peptide of claim 8 , wherein said peptide is conjugated to at least one effector molecule.

38. The peptide of claim 37 , wherein said at least one effector molecule comprises a therapeutic agent, a detectable group, a lipid, or a liposome.

39. The peptide of claim 37 , wherein said at least one effector molecule comprises a toxin and/or an amphipathic antimicrobial peptide.

40. A method of delivering at least one effector molecule to a cell of interest, comprising:

contacting the targeting peptide of claim 8 to a cell of interest under conditions in which said targeting peptide is internalized therein, wherein said targeting peptide is coupled to said at least one effector molecule.

41. The method of claim 40 , wherein said at least one effector molecule comprises a therapeutic agent or a detectable group.

42. The method of claim 40 , wherein said cell of interest is a eukaryotic cell.