Suppression of matrix metalloproteinase-9 expression by RNA interference inhibits SGC7901 gastric adenocarcinoma cell growth and invasion in vitro and in vivo

Matrix metalloproteinase-9 (MMP-9) is considered the key enzyme that degrades extracellular matrix (ECM) via breaking down type IV collagens. Up-regulated MMP-9 promotes growth and invasion of gastric adenocarcinomas. The present study is to block MMP-9 expression in gastric adenocarcinoma cells in order to inhibit tumor growth and invasion. The association between MMP-9 expression and tumor pathology was reconfirmed by applying immunohistochemistry on tissue arrays. Small interference RNAs (siRNA) targeted on human MMP-9 were used to suppress gene expression in SGC7901 human gastric adenocarcinoma cells. Cell growth and invasion were significantly inhibited in specific siRNA-targeted cells. In addition, we generate a SGC7901-subcutaneous mice model to observe anti-tumor effects from RNA interference (RNAi). Data showed tumor masses in MMP-9 siRNA-treated mice were significantly smaller than those in control mice. The expression of vascular endothelial growth factor and proliferating cell nuclear antigen were down-regulated in MMP-9 siRNA treated cells. Our results demonstrate that MMP-9 targeted RNAi is able to successfully suppress MMP-9 gene expression and inhibit cell growth and invasion of SGC7901 gastric adenocarcinoma in vitro and in vivo. MMP-9 is a potential therapeutic target for gastric adenocarcinomas.