Abstract
Endothelial protein C receptor (EPCR) has been implicated in the carcinogenesis of diverse tumor types. This tumor-promoting effect of EPCR is associated with the upregulation of activated protein C and the activation of protease-activated receptor 1 (PAR-1). However, the exact role of EPCR in gastric cancer (GC) and the mechanisms underlying the regulation of EPCR remain elusive. In the present study, we investigated the effects of EPCR on human GC cells, as well as the underlying mechanisms. An siRNA inference system was used to knock down the expression of EPCR in GC cells, and CCK-8, colony formation and Transwell assays were performed to determine the effects of EPCR knockdown on the proliferation and migration of the tumor cells. Additionally, cell cycle distribution and apoptosis were assessed by flow cytometry, and activated PAR-1 levels were determined by cell ELISA. The results indicated that the proliferation, clonogenicity and migration were significantly reduced and that the cell cycle was arrested in the Gap 1 phase by EPCR knockdown in SGC7901 and AGS cells. Meanwhile, apoptosis was promoted by EPCR knockdown in the two cell lines. The activation of PAR-1 on the cell surface of SGC7901 and AGS cells was significantly reduced after the knockdown of EPCR. By contrast, blockade of PAR-1 reduced the proliferation and migration of gastric cells in vitro. Additionally, after the knockdown of EPCR or treatment with PAR-1 antibody, the expression of pERK1/2 was significantly downregulated in the SGC7901 and AGS cells, while the expression levels of p-AKT (S473) and p-AKT (T308) were unchanged. The findings of the present study demonstrated that EPCR exerts pro-carcinogenic effects in GC cells in a PAR-1-dependent manner via the ERK1/2-MAPK pathway. Thus, EPCR may be a potential molecular diagnostic or therapeutic target for GC.