Peptides that specifically bind HGF receptor (cMet) and uses thereof

1. An isolated polypeptide which binds cMet or a complex comprising cMet and HGF, wherein the polypeptide comprises the amino acid sequence selected from the group consisting of:

(a) GSX1X2X3CX4X5X6X7CX8X9X10APGGK (SEQ ID NO:525), in which

X1 is F, L, S, W, Y, or M;

X2 is I, Y, H, T, or N;

X3 is I, L, D, M, F, or S;

X4 is P, R, W, N, or E;

X5 is W, Y, E, P, L, T, or G;

X6 is S, T, D, F, E, W, G, or Q;

X7 is F, W, N, Q, E, R, or A;

X8 is G, N, H, R, M, I, D, V, or T;

X9 is S, K, F, M, T, D, or L; and

X10 is S, P, T, L, Y, N, H, Q, or W.

2. The isolated polypeptide of claim 1 , wherein:

in (a),

X1 is F, L, S, W, Y, or M;

X2 is I, Y, H, T, or N;

X3 is I;

X4 is W or P;

X5 is W, Y, E, P, L, T, or G;

X6 is S, T, D, F, E, W, G, or Q;

X7 is F, W, N, Q, E, R, or A;

X8 is G, N, H, R, M, I, D, V, or T;

X9 is S, K, F, M, T, D, or L; and

X10 is S, P, T, L, Y, N, H, Q, or W.

3. The isolated polypeptide of claim 1 , wherein the polypeptide comprises the amino acid sequence selected from the group consisting of SEQ ID NOS: 1-10.

4. The isolated polypeptide of claim 1 , wherein the polypeptide is multimeric.

5. The isolated polypeptide of claim 1 , wherein the polypeptide is conjugated to a label or a therapeutic agent.

6. The isolated polypeptide of claim 5 , wherein the label or therapeutic agent is conjugated to the polypeptide via a linker.

7. The isolated polypeptide of claim 1 , wherein the polypeptide is incorporated into ultrasound bubbles, microparticles, microspheres, emulsions, or liposomes.

8. The isolated polypeptide of claim 5 , wherein the polypeptide is conjugated to a label appropriate for diagnostic detection to form a diagnostic imaging contrast agent.

9. The isolated polypeptide of claim 8 , wherein the label is selected from the group consisting of an enzyme, a fluorescent compound, an ultrasound contrast agent, a liposome and an optical dye.

10. The isolated polypeptide of claim 5 , wherein the label is:

(i) a radioactive label, which optionally is selected from the group consisting of 18 F, 124 I, 125 I, 131 I, 77 Br, 76 Br, 99m Tc, 51 Cr, 67 Ga, 68 Ga, 47 Sc, 167 Tm, 141 Ce, 111 In, 168 Yb, 175 Yb, 140 La, 90 Y, 88 Y, 153 Sm, 166 Ho, 165 Dy, 62 Cu, 64 CU, 67 Cu, 97 Ru, 103 Ru, 186 Re, 188 Re, 203 Pb, 211 Bi, 212 Bi, 213 Bi, 214 Bi, 105 Rh, 109 Pd, 117m Sn, 149 Pm, 161 Tb, 177 Lu, 198 Au and 199 Au, or

(ii) a paramagnetic metal atom selected from the group consisting of Gd 3+ , Mn 2+ , Cu 2+ , Fe 2+ , Co 2+ , Ni 2+ , Eu 3+ , Dy 3+ , Pr 3+ , Cr 3+ , Co 3+ , Fe 3+ , Ti 3+ , Tb 3+ , Nd 3+ , Sm 3+ , Ho 3+ , Er 3+ , Pa 4+ , and Eu 2+ .

11. A method of imaging cMet or a complex of cMet and HGF in a subject in need thereof, the method comprising:

(i) providing a polypeptide of claim 1 ;

(ii) administering to the subject the polypeptide; and

(iii) imaging the subject by detecting the polypeptide in the subject.

12. The method of claim 11 , wherein the subject is a human patient suspected of having a hyperproliferative disorder, or a disorder associated with angiogenesis or neovascularization.

13. The method of claim 11 , wherein step (iii) is performed by magnetic resonance imaging, ultrasound imaging, optical imaging, sonoluminescence imaging, photo acoustic imaging, x-ray imaging, or radionuclide imaging.

14. A method of purifying cMet or a cMet and HGF complex from a solution containing it, the method comprising:

(a) contacting the solution with at least one polypeptide set forth in claim 1 , which is immobilized on a solid substrate, and

(b) separating the polypeptide from the solution.