Abstract:
Objective:To evaluate the interference effects of using a replication-defective adenovirus vector on the Sur -vivin gene in the colon carcinoma cell line SW480 and to investigate the proliferation and apoptosis of SW480 cells after Survivin gene silencing. Methods:To study the biological function of Survivin in colon cancer, RNA interference was applied to knock down survivin expression in the colon cancer cell line SW 480 by recombinant replication-defective adenovirus pro -ducing Survivin small hairpin RNA (Survivin-shRNA). The infection rates were detected at different multiplicity of infection (MOI) at 48h after transfection and the optimized one was chosen for the subsequent experiments. After Survivin gene si-lencing, expression of Survivin mRNA and protein was detected by RT-PCR and Western blot, respectively. The cell cycle and the degree of cell apoptosis were analyzed by flow cytometry (FCM) at 48h after transfection. To analyze the effect of shRNA-Survivin on the proliferation of tumor cells, we performed MTT and colony formation assays. Results: The infection rate was significantly different when the MOI was at 10-50, and the rate was dose-dependent. There was no difference be -tween MOI= 50and MOI=100 . The optimized MOI was 50and was used at this level for the following experiments. RT-PCR and Wertern blot results demonstrated that expression of Survivin protein and the Survivin gene was down-regulated in co-lon cancer cells after Survivin gene silencing. The rate of apoptosis was obviously increased after Survivin gene silencing (P<0.05). After Survivin gene silencing, the number of cells in the G1/S phase was increased and that in G2/M phase was decreased, with a significant difference (P<0.05). MTT and colony-formation assays showed that shRNA-Survivin had an obvious inhibitory effect on the growth of colon cancer cells in the experimental group (P<0.05). Conclusion:Survivin was over expressed in colon cancer SW480 cells and the replication-defective adenovirus vector carrying Survivin-shRNA can suppress expression of Survivin mRNA and protein and thus can induce cell apoptosis and block cell division by blocking cells in G1/S phase.