靶向抑制COX-2基因对胃癌细胞BGC823凋亡及药物敏感性的影响

Effect of COX-2 gene silencing on apotosis and drug susceptibility of gastric cancer cell BGC823

目的:研究siRNA靶向抑制环氧合酶-2(COX-2)基因后对胃癌细胞BGC823增殖、凋亡及药物敏感性的影响。方法:将COX-2 siRNA(siRNA-COX-2组)及negative control siRNA(siRNA-control组)序列转入细胞BGC823中,检测细胞增殖能力,观察多西紫杉醇(docetaxel艾素)、奥沙利铂(L-OHP)、5-氟尿嘧啶(5-FU)的药物敏感性变化,及转染前后BGC823细胞COX-2、β-catenin、Bcl-2 mRNA基因和蛋白的表达。结果:siRNA-COX-2组细胞在转染后第四天开始增殖能力下降,与siRNA-control组差异存在明显统计学意义(P<0.05),而siRNA-control组细胞于BGC823组增殖能力差异无明显统计学意义(P>0.05)。MTT法检测转染后胃癌细胞对艾素、奥沙利铂、5-氟尿嘧啶的IC50较转染前药物敏感性明显增加。流式细胞术检测转染前后胃癌细胞凋亡率为(3.08%±0.27%vs 16.14%±1.89%,P<0.05),转染后凋亡明显增加(P<0.05)。qRT-PCR法检测发现转染后COX-2、β-catenin、Bcl-2 mRNA基因的表达明显下降,Western blot检测发现,转染后48小时COX-2蛋白表达达到最低,转染后48小时β-catenin、Bcl-2蛋白表达明显下降(P<0.05)。结论:通过下调COX-2基因的表达,可有效抑制WNT信号通路的激活,同时有效降低Bcl-2基因的表达。抑制COX-2基因后可有效降低胃癌细胞BGC823的细胞增殖能力,可有效提高对艾素、奥沙利铂、5-氟尿嘧啶的药物敏感性,有效促进细胞凋亡。

Objective：To investigate the influence of cycloxyenase-2（COX-2） gene silencing on proliferation,apotosis and drug susceptibility of gastric cancer cell BGC823.Methods：COX-2 siRNA and negative control siRNA were transfected into the BGC823.Changes in cell proliferation was measured by cell counting method.The cellular sensitivity to docetaxel,oxaliplatin,5-fluorouracil was detected.Then detect the expression of COX-2,β-catenin and Bcl-2 before and after transfection.Results：The proliferation ability of siRNA-COX-2 group was decreased after 4 days post transfection.There was difference between the siRNA-COX-2 group and siRNA-control group（P〈0.05）.But the siRNA-COX-2 group and siRNA-control group had no statistic significance（P〉0.05）.The IC50 of gastric cancer cells cellular sensitivity to docetaxel,oxaliplatin and 5-fluorouracil were increased obviously.The drug sensitivity increased significantly after transfection.The apoptosis rate of gastric cancer cells were markedly increased after transfection（3.08%±0.27% vs 16.14%±1.89%,P〈0.05）.The expression of COX-2 mRNA,β-catenin mRNA and Bcl-2 mRNA were significantly lower detected by qRT-PCR.The protein expression of COX-2 had fallen to the lowest level ever after 24 hours post transfection.The protein expression of β-catenin and Bcl-2 decreased obviously after 48 hours post transfection.Conclusion：Downregulating the expression of COX-2 gene can effectively inhibit the activation of WNT signaling pathway,and also can reduce the expression of Bcl-2 gene.Inhibition of COX-2 gene expression in gastric cancer cell line BGC823 can effectively reduce cell proliferation,migration and invasion.It also can improve the drug sensitivity of docetaxel,oxaliplatin,5-fluorouracil,promote the cell apoptosis.