Inhibiting effects of a cyclic peptide CNGRC on proliferation and migration of tumor cells in vitro

摘要

The cyclic peptide Cys-Asn-Gly-Arg-Cys (CNGRC) has previously been demonstrated as a tumor vasculature-homing peptide, which can specifically bind to CD13/aminopeptidase N in vivo. However, the effect of the peptide (CNGRC) binding to tumor cells in vitro has not yet been reported. In this study, CNGRC and an irrelevant linear control peptide (SVSVG) were employed to investigate the specific binding properties and other cellular influences in vitro. Immunofluorescence revealed that the peptide CNGRC demonstrated high specificities to the cells MDA-MB-435S, A549, MDA-MB-231, SK-OV-3 and EA.hy926, respectively. The cell viability assay indicated that CNGRC inhibited the proliferation of tumor cells at 24, 48 and 72 h. Furthermore, the peptide efficiently inhibited the migration of tumor cells, but promoted the migration of the human umbilical vein cell line. These results demonstrate that the synthetic peptide CNGRC can bind to the tumor cells without aminopeptidase N (CD13) expressed on the membranes. Therefore, it is supposed that the mechanism of the peptide binding to tumor cells in vitro may be different from that in vivo.