Establishment Of Gastric Cancer Cell Clone With MMP-9 Gene Silence Using RNA Interference

The major characteristics of malignant tumour cells are invasion and metastasis, of which proteolytic degradation of the extra cellular matrix, including basement membrane by matrixmetalloproteinases (MMPs) is one of the essential events. As a kind of matrixmetallo-proteinases, matrixmetalloproteinase-9(MMP-9) can degradate extra-cellular matrix and basement membrane, which would facilitate the invasion, metastasis and interstitial angiogenesis. MMP-9 is expressed predominantly by tumour cells in various cancers. Immunohistochemical studies have shown that the expression of MMP-9 correlates with tumor invasion,metastasis and prognosis in both colorectal adenocarcinoma and esophageal squamous cell carcinoma. But it is not certain what will happen when MMP-9 is inhibitted with RNAi.Over the last years, RNA interference(RNAi) has been recognized as a major mechanism of post-transcriptional gene silence in the nematode Caenorhabditis elegans and the fruit fly Drosophila, as well as in plants. This phenomenon is based on double-stranded RNA(dsRNA) that triggers the silence of gene expression in a sequence-specific manner. Now, there are many study on the mechanism, while has become a routine tool for transient knockdown of gene expression in a wide range of organisms. In our experiment, we constructed a modal with MMP-9 geneknockout by RNAi in poorly differentiated gastric adenocarcinoma cell BGC823. In the process of construction, we cloned a stable RNAi system with liposome transfection. Then applied immunofluorescence technique , gelatin zymography and western blot to detect the expression of MMP-9 in BGC823.The experiment applies molecular cloning and RNA infection techniques to inhibit MMP-9 gene in level of transcription and translation, for researching the role and mechanism of the invasion and metastasis in gastric cancer cell. Experimental key is to obtain a higher interference effects gastric cancer cell line that transfected plasmid successfully. The experiment is the basis of the experimental model in vitro. The resulds would show the relationship between gastric cancer cell invasion and MMP-9, provide evidences for early diagnosis, gene therapy, and judging the prognosis in gastric cancer.