[The effect of siRNA on inhibiting cyclooxygenase-2 gene expression in gastric adenocarcinoma cell].

OBJECTIVE: To observe the cyclooxygenase-2 (COX-2) expression and the cell proliferation and apoptosis of gastric adenocarcinoma cells after transiently transfecting gastric cancer cells using specific COX-2 small interfering RNA (siRN) and discuss the role of COX-2 in gastric tumorigenesis and the effect of RNA interference (RNAi) as anti-cancer gene therapy. METHODS: Three groups were included in the study, i. e. a COX-2 siRNA group, a non-sense siRNA group and a control group. Gastric adenocarcinoma cells SGC7901 were cultured at 37 degrees C in an atmosphere containing 5% CO2. 72 hours after transfecting SGC7901 cells with specific COX-2 siRNA or non-sense siRNA, RT-PCR was used to detect COX-2 mRNA, immunohistochemistry and Western blot were taken to detect the expression of COX-2 protein and flow cytometry was taken to detect the cell cycle and apoptosis. MTT method was used to detect the proliferation and activity of the cells every day for one week after transfection. RESULTS: The expression of COX-2 mRNA and protein in the COX-2 siRNA group was obviously suppressed as compared with non-sense siRNA group and control group. No change was found between the non-sense siRNA group and the control group. The reduced expression of COX-2 could inhibit SGC7901 cells proliferation and induce cell apoptosis, but had no effect on cancer cell cycle. CONCLUSIONS: The experimental results suggest that effectively inhibiting the expression of COX-2 can suppress the proliferation of gastric adenocarcinoma cell and promote the process of cancer cell apoptosis, so RNAi is a powerful tool of gene therapeutic method.