siRNA特异性抑制卵巢癌细胞生长因子受体-2基因表达及其意义的研究

目的探讨RNA干扰(RNAi)抑制卵巢癌细胞表皮生长因子受体-2(HER-2)基因的表达及其细胞效应。方法实验分为以下3组空白对照组(未经转染的人卵巢癌SKOV-3细胞)、转染非特异性的siRNA组及转染特异性的siRNA组。干涉后5d加顺铂。采用半定量PCR技术(RT-PCR)和Western印迹法检测HER-2mRNA和蛋白的表达,用流式细胞仪检测细胞凋亡,用四甲基偶氮唑盐(MTT)比色法检测细胞对顺铂的化学敏感性的变化,分析观察细胞生物学特性的改变。结果HER-2siRNA对HER-2mRNA表达明显抑制,作用能持续10d左右;干涉第7天后开始出现蛋白质表达的明显减弱,转染特异性siRNA组的蛋白质阳性表达率为(25·5±0·8)%,非特异性siRNA组为(95·7±0·8)%,空白对照组为(96·6±1·2)%,前组与后两组比较差异有统计学意义(均P<0·001)。干涉后随着HER-2mRNA表达下降,细胞凋亡增加,第6天凋亡率最高,达(53·2±1·0)%,转染非特异性siRNA组为(4·1±0·3)%,空白对照组为(4·1±0·3)%,差异有统计学意义(P<0·001);干涉后,转染特异性siRNA组的细胞存活率为(58·4±0·8)%,转染非特异性siRNA组为(68·0±0·6)%,空白对照组为(67·0±0·3)%,前组与后两组比较差异有统计学意义(均P<0·001)。结论体外合成的siRNA能有效抑制SKOV-3细胞中HER-2表达,促进细胞的凋亡,提高细胞对顺铂的敏感性,RNAi为卵巢癌的基因治疗提供了一种新策略。

Specific inhibition of HER-2 expression in ovarian carcinoma cells by siRNA targeting HER-2

OBJECTIVE: To investigate the effects of RNA interference (RNAi) targeting HER-2 gene on the biological traits of human ovarian carcinoma. METHODS: siRNA specific to HER-2 gene was synthesized according to the sequence in the GenBank. Human ovarian carcinoma cells of the line SKOV-3 were cultured and divided into 3 groups: control group; non-specific group, transfected with non-specific siRNA; and specific group, transfected with specific HER-2 siRNA. On the 5th day after transfection cisplatin was added into the culture fluid. The expression of HER-2 mRNA and the expression of protein both before and after transfection were detected by RT-PCR and Western blotting. The cell apoptosis was assessed by flow cytometry. The chemosensitivity of transfected cells to cisplatin was determined by MTT method. RESULTS: Since the 3rd day after transfection the expression of HER-2 mRNA of the HER-2 siRNA group was suppressed till 10 days later. On the 7th day after transfection the expression rate of HER-2 protein of the HER-2 siRNA group was (25.5 +/- 0.8)%, significantly lower than those of the nonspecific siRNA group and control group, (95.7 +/- 0.8)% and (96.6 +/- 1.2)% respectively (both P < 0.001). On the 9th day after transfection no expression of HER-2 protein was found in the HER-2 siRNA group. The apoptosis rate of SKOV-3 cells increased time-dependently after transfection in the HER-2 siRNA group and reached the peak, (53.2 +/- 1.0)% on the 6th day, significantly higher than those of the non-specific siRNA group and control group, (4.1 +/- 0.3)% and (4.1 +/- 0.3)% respectively (both P < 0.001). After exposure to cisplatin for 24 hours, the survival rate of the HER-2 siRNA group was (58.4 +/- 0.8)%, significantly higher than those of the nonspecific siRNA group and control group, (68.0 +/- 0.6)% and (67.0 +/- 0.3)% respectively (both P < 0.001). CONCLUSION: siRNA targeting HER-2 synthesized in vitro and transfected into human ovarian carcinoma cells effectively suppresses the HER-2 expression, induces cell apoptosis, and increases the sensitivity to cisplatin of the cells. The successful application of HER-2 siRNA extends the list of available therapeutic modalities in the treatment of human ovarian cancer.