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目的探讨RNA干扰下调Survivin基因表达后膀胱癌细胞生物学行为变化及Sur- vivin基因抗凋亡机制。方法设计、合成一对Survivin编码基因序列特异的小分子干扰RNA(siR- NA),用脂质体包裹转染T24膀胱癌细胞,分不同的浓度组(50～200 nmol/L)。噻唑蓝(MTT)法检测细胞生长情况,流式细胞仪测定细胞凋亡率,实时定量聚合酶链反应(PCR)检测Survivin基因和Caspasc-3基因mRNA表达。结果Survivin编码基因序列特异性siRNA能有效下调Survivin基因表达水平,并呈剂量和时间依赖性,最大效应浓度为100 nmol/L,此时与对照比较Survivin表达水平下调75．91%,并显著的抑制了细胞生长,抑制率达55．29%,差异有统计学意义(P＜0．05)。同时,Caspase-3 mRNA表达水平明显上升达239．80%,细胞凋亡率亦增加至45．70%,与对照相比差异有统计学意义(P＜0．05)。结论RNA干扰显著下调Survivin基因表达后,能明显促进T24膀胱癌细胞凋亡并抑制其增殖；Survivin基因可能是通过下调Caspase-3表达来抑制凋亡。
Objective To investigate the biological behavior of bladder cancer cells after Survivin gene down-regulation by RNA interference and the anti-apoptotic mechanism of Survivin gene. Methods A pair of small interfering RNA (siRNA) specific to Survivin encoding gene was designed and synthesized. T24 bladder cancer cells were transfected with lipofectamine in different concentrations (50 ~ 200 nmol / L). The growth of cells was detected by MTT assay, the apoptosis rate was determined by flow cytometry, and the mRNA expression of Survivin and Caspase-3 was detected by real-time quantitative polymerase chain reaction (PCR). Results The sequence-specific siRNA of Survivin gene could downregulate the expression of Survivin gene in a dose-and time-dependent manner with the maximum concentration of 100 nmol / L. Survivin expression was down-regulated by 75.91% compared with the control Inhibition of cell growth, inhibition rate of 55.29%, the difference was statistically significant (P <0.05). At the same time, Caspase-3 mRNA expression increased by 239.80% and apoptosis rate increased to 45.70%, which was significantly different from the control (P <0.05). Conclusions RNAi significantly down-regulates the expression of Survivin gene, which can significantly promote the apoptosis and inhibit the proliferation of T24 bladder cancer cells. Survivin gene may inhibit apoptosis by down-regulating the expression of Caspase-3.