The Mechanism Of The BFGF Antagonist Peptide On BFGF-induced Proliferation Of Gastric Cancer Cells And Angiogenesis

Aim In our previous study，we have obtained a high-affinity bFGF-binding peptide (named P7)from the phage display random heptapeptide library. Herein, we further investigated themechanism of anti-proliferation and anti-angiogenesis effects of P7peptides on bFGF-stimulatedgastric cancer cells and vascular endothelial cells.Methods MTT assay was used to evaluate the effect of P7peptides on the proliferation ofhuman gastric cancer cell lines SGC-7901, AGS and BGC-823stimulated with bFGF. Flowcytometry was applied to analyze the effect of P7on cell cycle progress of bFGF-stimulatedSGC-7901cells. Western blot was used to check the effect of P7on bFGF-induced activation ofErkl/2and P38in SGC-7901cells. Immunofluorescence combined with confocal microscopywas carried out to investigate the influence of P7on bFGF internalization into SGC-7901cells.The influence of P7peptides on the expression levels of angiogenic proteins including uPA,MMP-2, MMP-9and VEGF in HUVEC-1,2induced by bFGF was checked by western blottingand ELISA. Separation of nuclear and cytoplasmic proteins followed by western blotting, andimmunofluorescence combined with confocal microscopy were carried out to analyze the effectof P7peptides on bFGF internalization.Results MTT assay showed that P7could inhibit cell proliferation induced by bFGF in adose-dependent manner while P7alone had no significant influence on the growth of SGC-7901,BGC-823and AGS cells. Flow cytometry analysis indicated that P7decreased S-phase cell ratiosand caused G0/G1phage arrest in bFGF-stimulated SGC-7901cells. Western blot analysisshowed that P7could reduce bFGF-induced Erkl/2and P38phosphorylation in SGC-7901cells.P7could also suppress bFGF internalization into SGC-7901and HUVEC-1,2cells, and decreasethe expressions of VEGF, uPA, MMP-2and MMP-9in HUVEC-1,2induced by bFGF.Conclusion P7peptides may inhibit the proliferation of bFGF-stimulated gastric cancer cellsin vitro via cell cycle arrest at the G0/G1phase, blockade of the activation of ERK and P38cascades, and suppression of bFGF internalization. P7peptides may exert the inhibitory effect onthe angiogenesis by suppressing bFGF internalization into the vascular endothelial cells anddown-regulating the expression levels of VEGF, uPA, MMP-2, and MMP-9in the vascularendothelial cells induced by bFGF. These results suggested that P7as the bFGF antagonist peptide might have therapeutic potential in gastric cancer.