RNAi-mediated inhibition of PDGF-D leads to decreased cell growth, invasion and angiogenesis in the SGC-7901 gastric cancer xenograft model.

Platelet-derived growth factor-D (PDGF-D) plays an important role in many types of human cancer. However, little is known about the function of this gene in gastric cancer. Here we demonstrated that PDGF-D is commonly overexpressed in gastric cancer. Silencing of PDGF-D using RNA interference significantly attenuated the proliferation and invasion potentials of SGC-7901 gastric cancer cells in which PDGF-D is overexpressed. Moreover, suppression of PDGF-D expression resulted in less activation of beta-catenin and its downstream effector genes, cyclin D1 and matrix metalloproteinases, which are known to be involved in cell proliferation and invasion, respectively. Further, downregulation of PDGF-D remarkably reduced VEGF expression and secretion and proangiogenic activities of SGC-7901 cells in vitro. Most importantly, PDGF-D downregulation caused a significant decrease in tumor growth and angiogenesis in a SGC-7901 xenograft model. Together these findings suggest that PDGF-D is involved in the promotion of gastric cancer growth, invasion and angiogenesis, and RNAi-mediated silencing of this gene may thus offer a promising therapeutic strategy for PDGF-D-overexpressing gastric cancer.