Inhibition of VEGF expression in tongue squamous cancer cells via RNA interference silencing of iNOS gene.

The purpose of this study was to investigate the regulatory role of the inducible nitric oxide synthase (iNOS) gene on vascular endothelial growth factor (VEGF) expression in oral squamous cancer cells. The RNA interference (RNAi) technique was used to silence iNOS gene expression by transfecting an expression vector containing short hairpin RNA (shRNA) for iNOS into Tca8113 tongue squamous cancer cells using cationic liposomes. Reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting were used to monitor iNOS and VEGF mRNA, as well as protein expression. iNOS mRNA expression was significantly downregulated 24 and 36 h after transfection, and iNOS protein expression was significantly downregulated at 36 and 48 h (P<0.05 versus control), showing that effective silencing was achieved. VEGF mRNA was significantly decreased 24 and 36 h post-transfection, and VEGF protein expression was significantly decreased at 36 and 48 h (P<0.05). RNAi can decrease iNOS gene expression and achieve a gene silencing effect. iNOS gene silencing reduces VEGF expression levels in Tca8113 cells. Thus, there is a relationship between iNOS and VEGF expression in tongue squamous cancer cells.