Department of Respiratory Medicine, The Union Hospital of FuJian Medical University, Fuzhou 350001, PR China.
Mol Med Rep. 2012 Apr;5(4):917-22. doi: 10.3892/mmr.2012.755. Epub 2012 Jan 13.
The survivin protein, a member of the inhibitors of apoptosis (IAP) family, has gained popularity as a therapeutic target for cancer due to its selective expression in tumor cells and its significant involvement in tumor cell viability. The aim of this study was to investigate the effect of the survivin-small interfering RNA (siRNA) plasmid on survivin expression in the human lung cancer cell line, A549, and to observe its effects on apoptosis and proliferation of A549 cells. A549 human lung cancer cells were transfected with survivin-targeting siRNA. The downregulation of survivin expression was determined by real-time polymerase chain reaction and western blotting. The proliferation of A549 cells was determined by MTT assay. The apoptotic rate and cell cycle distribution were analyzed by flow cytometry (FCM). Caspase-9 activity was also detected to study the apoptosis of lung cancer cells induced by siRNA against survivin. The sequence-specific siRNA efficiently and specifically downregulated the expression of survivin at both the mRNA and protein levels. Downregulation of survivin expression dramatically suppressed the proliferation of A549 cells and arrested the cells at the G (1)/G (0) phase. Caspase-9 activity was significantly increased in A549 cells transfected with siRNA against survivin. In this study, we found that survivin-specific siRNA can efficiently suppress the expression of survivin, increase apoptosis and inhibit A549 cell proliferation. Our findings further indicate the possibility that the antitumor effects of survivin-siRNA are mediated through the activation of caspase-9.
生存素蛋白是凋亡抑制因子（IAP）家族的成员，由于其在肿瘤细胞中的选择性表达及其在肿瘤细胞活力中的重要作用，已成为癌症治疗的热门靶点。本研究旨在探讨生存素小干扰 RNA（siRNA）质粒对人肺癌细胞系 A549 中生存素表达的影响，并观察其对 A549 细胞凋亡和增殖的影响。用生存素靶向 siRNA 转染 A549 人肺癌细胞。通过实时聚合酶链反应和 Western blot 测定生存素表达的下调。通过 MTT 测定法测定 A549 细胞的增殖。通过流式细胞术（FCM）分析细胞凋亡率和细胞周期分布。还检测了 caspase-9 活性以研究针对生存素的 siRNA 诱导的肺癌细胞凋亡。序列特异性 siRNA 可有效且特异性地下调 mRNA 和蛋白水平的生存素表达。生存素表达下调显著抑制了 A549 细胞的增殖，并使细胞停滞在 G1/G0 期。用针对生存素的 siRNA 转染的 A549 细胞中 caspase-9 活性显著增加。在本研究中，我们发现生存素特异性 siRNA 可有效抑制生存素的表达，增加细胞凋亡并抑制 A549 细胞增殖。我们的研究结果进一步表明，生存素-siRNA 的抗肿瘤作用可能是通过 caspase-9 的激活介导的。
