Suppression of tumor growth by novel peptides homing to tumor-derived new blood vessels.

Novel peptides homing to angiogenic vessels were recently isolated from a phage-displayed random pentadecapeptide library. One of the isolated peptides, ASSSYPLIHWRPWAR, significantly suppressed the migration of VEGF-stimulated human umbilical vein endothelial cells. Dendoric ASSSYPLIHWRPWAR-peptide suppressed the formation of new blood vessels in dorsal air sac model mice. Furthermore, ASSSYPLIHWRPWAR-peptide and the fragment peptides containing WRP, which is revealed to be an epitope sequence, significantly suppressed the tumor growth, although 15-mer shuffled peptide derived from ASSSYPLIHWRPWAR and pentapeptides with alanine substitution of each residue of WRP did not. Taken together, ASSSYPLIHWRPWAR-peptide may cause tumor dormancy through inhibition of angiogenesis, and the WRP sequence may be the minimal and essential sequence for this activity.