[Antiangiogenic Effect of Oyster Polypeptide (OPP).]

Drugs which block tumor angiogenesis will be likely effective towards inhibiting tumor growth for angiogenesis being a prerequisite for tumor growth and metastasis. Therefore, antiangiogenesis has become a promising strategy for the treatment of cancer. Investigation on both antiangiogenic effect and mechanism(s) of oyster polypeptide (OPP) were performed via experiments of chicken embryos model in vivo and human umbilical vein endothelial cells (HUVECs) in vitro.

The methods employed in experiment were chorioallantoic membrane (CAM) angiogenesis in chicken embryos in vivo, MTT cell survival assay, flat plate scarification, transwell plates assay, matrigel-induced tube formation assay and transmission electron microscope et al. and the OPP's effects on angiogenesis was observed.

Study showed that treatment with OPP resulted in significant inhibition of chorioallantoic membrane (CAM) angiogenesis in chicken embryos. MTT cell survival assay showed that treatment with OPP resulted in strong inhibition of HUVECs growth, with an IC50 of 400 mug/mL. Flat plate scarification suggested that OPP (200 mug/mL, 400 mug/mL and 800 mug/mL) distinctly inhibited HUVECs' migration (18.75%, 37.93%, 74.07% respectively, treatment for 12 h). Treatment with OPP of different concentrations (200 mug/mL, 400 mug/mL and 800 mug/mL) significantly reduced the density of the migration cells by 15.5%, 37.2% and 67.24% (P<0.05) respectively. Matrigel-induced tube formation assay showed that OPP resulted in striking inhibition of tube formation of 52.43%, 84.47% and 96.12% (P<0.01) at 200 mug/mL, 400 mug/mL and 800 mug/mL (treatment for 10 h) respectively. In addition, the apoptotic analysis by transmission electron microscope showed that OPP (400 mug/mL, treatment for 48 h) distinctly induced HUVECs' apoptosis.

This study strikingly showed that OPP could inhibit angiogenesis through its effects on vascular endothelial cells directly and the inhibition of their proliferation, migration, angiogenic ability, and induction of their apoptosis might be the antiangiogenic mechanism of OPP.