RNAi-mediated gene silencing of vascular endothelial growth factor-C inhibits tumor lymphangiogenesis and growth of gastric cancer in vivo in mice.

Overexpression of vascular endothelial growth factor-C (VEGF-C) has been implicated as a critical molecular signal in tumor development by promoting intratumoral lymphangiogenesis. The aim of this study was to explore whether small hairpin RNA (shRNA) targeting VEGF-C could inhibit gastric cancer lymphangiogenesis and tumor growth. Plasmid-mediated expression of VEGF-C-shRNA was employed to silence VEGF-C gene expression in human SGC-7901 cell lines. The inhibition of the target gene expression was quantified by real-time quantitative polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay. In vitro, the cell viability was determined by MTT assay, flow cytometry analysis, and migration assay. After VEGF-C knockdown was confirmed, the stable cells were inoculated into nude mice. Tumor growth, lymph vessel density (LVD), and microvascular density were compared for mice administered either VEGF-C-shRNA or control. VEGF-C-shRNA causes effective and specific downregulation of VEGF-C expression (P<0.05). The migration activity of SGC-7901 cells was attenuated in vitro (P<0.05). Tumor growth rate and LVD was suppressed in vivo (P<0.05). VEGF-C-shRNA effectively suppressed gastric cancer cell migration in vivo, retards tumorigenicity, and lymphangiogenesis in nude mice.