目的 探讨siRNA沉默检测点激酶1(Chk1)基因对乳腺癌细胞MCF-7增殖和周期的影响及其作用机制.方法 采用RNAi技术将乳腺癌细胞MCF-7中Chk1基因沉默,用Western blotting检测转染前后MCF-7细胞中Chk1蛋白表达情况；采用MTT比色法和流式细胞术分析Chk1基因沉默对乳腺癌细胞MCF-7增殖和周期的影响.结果 Chk1 siRNA转染后,MCF-7细胞中Chk1蛋白表达下降约82％,明显低于未转染组和脂质体转染组(P＜0.05).Chk1 siRNA转染组转染48h的MCF-7细胞增殖活性下降,其增殖抑制率为44.7％,明显高于脂质体转染组的5.26％ (P ＜0.05).流式细胞仪检测显示,Chk1 siRNA转染组G2/M期比例为(11.3±0.7)％,明显低于未转染组(44.2±1.9)％和脂质体转染组(45.3±2.1)％,差异均有统计学意义(P＜0.05).结论 siRNA沉默Chk1基因可明显抑制人乳腺癌细胞MCF-7增殖,并且其抑制增殖作用与减弱G2/M期阻滞有关.%Objective To investigate the effects and mechanism of checkpoint kinase 1 siRNA transfection on the proliferation of human mammary adenocarcinoma MCF-7 cell. Methods The siRNA targeting at Chkl gene was transfected into MCF-7 cells. The protein expression of Chkl was detected by Western blotting. Cell viability and cell cycle rates were determined by MTT assay and FCM. Results The Chkl expression at protein levels in Chkl siRNA-transfected group was reduced by about 82% compared with un-transfection and lipofectamine group (P < 0.05). The lack of Chkl expression resulted in decreased cellular proliferation activity. The inhibition rate for 48h in Chkl siRNA-transfected group was 44. 7% (P < 0. 05), which was higher than that of lipofectamine group (5. 26%). In addition, the percentage of the Chkl siRNA-transfected cells in G2/M phase was (11. 3 ±0.1)% , which was lower than (44. 2 ±1.9)% and (45.3 ±2. 1)% in the remaining two groups(P <0.05). Conclusion Chkl siRNA obviously decreases the Chkl expression in MCF-7 cells and cellular proliferation activity relates to the block of cell cycle in G2/M phase.
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