Identification of a peptide for folate receptor alpha by phage display and its tumor targeting activity in ovary cancer xenograft

The expression level of folate receptor alpha (FRa) is located highly rate in ovarian cancer though it is remained absent in normal tissues. This highly tumor restricted expression profile makes FRa a promising target for tumor therapy and diagnosis. In this research we report a FRa binding peptide C7(Met-His-Thr-Ala-Pro-Gly-Trp-Gly-Tyr-Arg-Leu-Ser) discovered by phage display and this peptide showed specific binding to FRa expressing cells by cell ELISA and flow cytometry. Tumor targeting ability of C7 was proved in vivo by both phage homing experiment and fluorescence imaging. C7 can be internalized by SKOV3 cells and its affinity to FRa was determined by MST. The molecular recognition was revealed by structure modeling, suggesting its binding mode with FR alpha.