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EFFECTS OF p53 GENE THERAPY COMBINED WITH CYCLOOXYGENASE-2 INHIBITOR ON CYCLOOXYGENASE-2 GENE EXPRESSION AND GROWTH INHIBITION OF HUMAN LUNG CANCER CELLS
Background Gene therapy by adenovirus-mediated wild-type p53 gene transfer has been shown to inhibit lung cancer growth in vitro, in animal models, and in human clinical trials. The antitumor effect of selective cyclooxygenase (COX)-2 inhibitors has been demonstrated in preclinical studies. However, no information is available on the effects of p53 gene therapy combined with selective COX-2 inhibitor on COX-2 gene expression and growth inhibition of human lung cancer cells. Methods We evaluated the effects of recombinant adenovirus-p53 (Ad-p53) gene therapy combined with selective COX-2 inhibitor on the proliferation, apoptosis, cell cycle arrest of human lung adenocarcinoma A549 cell line, and the effects of tumor suppressor exogenous wild type p53 on COX-2 gene expression. Results Ad-p53 gene therapy combined with selective COX-2 inhibitor celecoxib shows significant synergistic inhibition effects on the growth of human lung adenocarcinoma A549 cell line. Exogenous p53 gene can suppress COX-2 gene expression. Conclusions Significant synergistic inhibition effects of A549 cell line by the combined Ad-p53 and selective COX-2 inhibitor celecoxib may be achieved by enhancement of growth inhibition, apoptosis induction and suppression of COX-2 gene expression. This study provides first evidence that the administration of p53 gene therapy in combination with COX-2 inhibitors might be a new clinical strategy for the treatment or prevention of NSCLC.
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干扰COX-2基因表达对人肺腺癌A2细胞体外恶性增殖的影响
背景与目的 COX-2在多种肿瘤组织中高表达,参与了肿瘤的发生发展,RNA干扰(RNAi)技术是一种经济、快捷、高效的抑制特异基因表达的技术手段.本研究应用RNAi技术研究干扰COX-2基因表达的抑制效果及抑制COX-2基因表达对A2细胞体外恶性增殖的影响.方法 以COX-2为靶点,构建3个带有人U6启动子的COX-2小干扰RNA(short interfering RNA,siRNA)表达载体.用脂质体lipofectamine介导,分别将3个siRNA表达载体及空载体转染到COX-2表达阳性的A2细胞,建立转染细胞株.采用反转录聚合酶链反应(RT-PCR)和Western blot方法检测COX-2表达水平的变化.通过细胞生长曲线、集落形成试验研究干扰COX-2基因表达对A2细胞体外增殖的影响.结果 经过PCR扩增、内切酶鉴定、DNA测序和BLAST比对证实3个siRNA和U6启动子序列正确并准确克隆到pEGFP载体.转染细胞株分别命名为A2-3、A2-7、A2-10和A2-P.转染后24 h、48 h、72 h,A2-P细胞均有绿色荧光表达,而A2-3、A2-7、A2-10细胞均未观察到绿色荧光.RT-PCR和Western blot结果显示,3个siRNA表达载体均发挥作用,COX-2表达受到抑制.与A2细胞比较,A2-3、A2-7、A2-10细胞的COX-2 mRNA表达量分别降低15.6%、20.4%和64.2%,COX-2蛋白表达量分别降低23.7%、36.7%和60.2%.细胞生长曲线、集落形成试验的结果显示,A2-10细胞生长减慢,集落形成率减少,而A2-3和A2-7细胞生长没有明显的改变.结论 应用RNAi技术熄灭COX-2基因表达对A2细胞的体外恶性增殖有明显的抑制作用.
关键词： cyclooxygenase-2 RNA干扰 体外 肺肿瘤
