Discovery And Characteristics Of A Novel Anti-tumor Peptide Targeting FGFRs And Its Mechanism Investigation

Aims: The fibroblast growth factor receptors(FGFRs)belongs to the family of receptor tyrosine kinases(RTKs),which they have aberrant signal activation in a variety of tumors,so they are the key targets for cancer therapy.In this study,we obtained a specific small peptide targeting FGFRs by using phage display peptide libraries,then evaluated its antitumor capability and explored its molecular mechanism.Methods: Firstly,taking the extracellular domain of the recombinant protein FGFR2?c as a target protein,high affinity phages were obtained after 4 rounds of screening by using the Ph.D.-12 phage display peptide library.Then sequenced and synthesized the candidate peptides,evaluated their activities of inhibiting cell growth by cell proliferation assay,and detected their affinity toward FGFR2 IIIc by isothermal titration calorimetry(ITC).Small peptide named as T1 was selected for further investigation.Evaluated its ability to inhibit tumors by cell proliferation assays and colony formation assays in vitro and in vivo nude mice xenograft tumor experiment.Detected the phosphorylation of downstream signal pathways by western blot.In addition,the genes' transcriptional levels in tumor cells treated with the T1 peptide were analyzed by transcriptome sequencing technique.Finally,the interaction patterns of the T1 peptide and FGFR were simulated by molecular docking and molecular dynamics simulations.Results: The T1 peptide has high affinities with FGFR1-4.The T1 peptide significantly inhibits the proliferation and colony formation of human gastric cancer cell(SGC-7901),and the growth of tumor in xenografts nude mice effectively.The T1 peptide reduces phosphorylation of FGFR and downstream signaling pathway induced by bFGF and alters the transcriptional expression of multiple genes involved in tumor signaling pathways such as Wnt.The results of molecular docking and dynamics simulation show that the T1 peptide may bind to the junction region of D2 and D3 domain of FGFR2(The active pocket of FGFR2).Conclusion: We have obtained a novel 12-amino acid peptide T1,which has high affinity toward FGFRs and has anti-tumor growth effect by binding to FGFRs.The study provides the foundation for the development of peptide antagonists of FGFRs.