目的： 研究siRNA干扰尼古丁乙酰胆碱受体α5（cholinergic receptor nicotinic alpha 5, CHRNA5 ）基因表达后对尼古丁促人肺癌A549细胞增殖作用的影响。 方法： 设计并合成CHRNA5-siRNA片段，并经脂质体介导转染A549细胞。荧光定量PCR、Western blotting检测转染后A549细胞中 CHRNA5 mRNA和蛋白的表达，MTT法检测CHRNA5-siRNA对尼古丁促A549细胞增殖作用的影响。 结果： 成功构建了CHRNA5-siRNA并成功转染A549细胞。CHRNA5-siRNA转染组A549细胞的 CHRNA5 mRNA 表达量明显低于si-NC转染对照组（0.196±0.044 vs 0.944±0.027, P<0.01），CHRNA5-siRNA转染组A549细胞的CHRNA5 蛋白表达量明显低于si-NC转染组（0.267±0.031 vs 0.745±0.035，P<0.01）。在无尼古丁作用时，CHRNA5-siRNA的转染不能抑制A549细胞的增殖。在尼古丁作用下，A549细胞增殖显著增加（P<001），CHRNA5-siRNA转染可明显抑制尼古丁的促增殖作用（P<0.01）。 结论： siRNA下调肺癌A549细胞中 CHRNA5 的表达可以抑制尼古丁促细胞增殖作用， CHRNA5 可能是肺癌治疗的潜在靶点之一。

Objective : To study the effect of siRNA targeting CHRNA5 (cholinergic receptor nicotinic alpha 5) gene expression on nicotine-induced proliferation of lung cancer A549 cells. Methods: CHRNA5-siRNA fragment was designed and synthesized, and then transfected into A549 cells by Lipofectamine assay. Expressions of CHRNA5 mRNA and protein in transfected-A549 cells were examined by FQ-PCR and Western blotting analysis, respectively. The effect of CHRNA5-siRNA on nicotine-induced proliferation of A549 cells was detected by MTT method. Results: CHRNA5-siRNA was successfully constructed and transfected into A549 cells. CHRNA5 mRNA expression in CHRNA5-siRNA-transfected A549 cells was significantly lower than that in control si-NC control siRNA transfected A549 cells (0.196±0.044 vs 0.944±0027, P<001), and CHRNA5 protein expression in CHRNA5-siRNA-transfected A549 cells was also lower than that in si-NC-transfected A549 cells (0.267±0.031 vs 0.745±0.035, P<0.01). When A549 cells were not treated with nicotine, CHRNA5-siRNA transfection inhibited the proliferation of A549 cells. But Nicotine increased the proliferation of A549 cells (P<0.01), and this positive effect was inhibited by CHRNA5-siRNA transfection (P<0.01). Conclusion: siRNA targeting CHRNA5 expression can inhibit nicotine-induced proliferation of A549 cells, which suggests that CHRNA5 may serve as a potential target for gene therapy of lung cancer.

中国博士后科学基金特别资助（No.200902575）；济南留学人员创业计划项目（No.20080407）