Survivin基因的shRNA 干扰对结肠癌SW480 细胞增殖和凋亡的影响*

Influence of the Survivin Gene on the Proliferation and Apoptosis of Colon Carcinoma Cells

  • 摘要: 目的:以携带shRNA 片段的腺病毒为载体,对结肠癌细胞SW480 中Survivin基因的表达进行干扰,研究其对肿瘤细胞中Survivin基因沉默效果及对细胞周期、凋亡和增殖的影响。方法:将构建好的携带Survivin-shRNA 片段腺病毒,体外转染结肠癌细胞株SW480。以EGFP为报告基因,采用流式细胞计数测定不同感染复数(MOI)下的转染效率,选取适当病毒浓度进行下一步实验。通过RT-PCR 和Western blot检测基因沉默后结肠癌细胞内Survivin mRNA和蛋白的表达水平;在Annexin V-FITC 和PI染色后通过流式细胞术检测并分析Survivin基因沉默后细胞周期和凋亡的变化;同时采用噻唑蓝(MTT)法、克隆增殖实验对细胞不同时期增殖活性进行观察,明确对细胞增殖的抑制时效性。结果:腺病毒转染后MOI 值在0~50时,剂量与转染效率成正比,确定最佳MOI 值为50并进行后续实验;shRNA 干扰后细胞内Survivin mRNA和蛋白表达水平降低,较对照细胞组差异有统计学意义(P<0.01)。 流式细胞仪检测结果显示基因沉默后细胞凋亡率升高,与对照组相比差异有统计学意义(P<0.01)。 同时基因沉默后,细胞周期也有明显变化,表现为G1/S 期细胞增多和G2/M期细胞减少,与对照细胞组相比差异有统计学意义(P<0.05)。 MTT 和单克隆平板实验均显示Survivin基因的沉默,对细胞的增殖和生长均具有明显抑制作用(P<0.05)。 结论:采用腺病毒对结肠癌进行靶向Survivin基因的shRNA 干扰,能有效降低目的基因的表达。其介导的Survivin基因的沉默,可以有效的诱导结肠癌细胞凋亡,同时Survivin基因可以通过抑制细胞G1/S 期转化来阻止细胞分裂,抑制细胞生长。

     

    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.

     

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