Objective To investigate the role of small interfering RNA (siRNA) targeted to survivin in combination with 5-fluorouracil (5-FU) in inhibiting the proliferation of MCF-7 cells. Methods A siRNA targeted to survivin was synthesized and transfected into MCF-7 cells via lipofectin. Changes of the cell growth activity in response to combined treatment with survivin siRNA and 5-FU or 5-FU treatment alone was evaluated by MTT assay. The Q method of Jin Zhenjun was used to evaluated synergism between the synthesized siRNA and 5-FU. Results Treatment with 5 nmol/L siRNA reduced the IC50 of 5-FU from 4.42 to 1.18 μg/ml, and the inhibitory effect of combined treatment on MCF-7 cells was higher than that of 5-FU alone (F=26.74, P＜0.01). Synergism effect (Q ≥ 1.15) was observed between 5-FU at lower concentrations and survivin siRNA. Conclusion siRNA may enhance the effectiveness of 5-FU in inhibiting the proliferation of MCF-7 cells.%目的研究以survivin为靶标的小干扰RNA(siRNA)与化疗药5-FU联合应用抑制MCF-7细胞增殖的作用.方法利用T7 RNA聚合酶体外转录合成siRNA并筛选出一条RNA干扰survivin基因的靶序列.以脂质体为载体,将survivin siRNA转染至人乳腺癌MCF-7细胞中,用四氮唑盐(MTT)法染色并计算siRNA联用5-FU对MCF-7细胞的抑制率,用SAS统计软件及金正均Q值法进行统计分析.结果单用5-FU处理细胞,其IC50为4.42 μg/ml,而加入5 nmol/L siRNA后,其IC50降为1.18 μg/ml,siRNA与5-FU联用对MCF-7细胞的抑制作用较单用5-FU明显增强(F=26.74,P＜0.01);Q值分析表明survivin siRNA与中低浓度的5-FU联用,有较好的协同作用(Q≥1.15).结论survivinsiRNA可显著增强5-FU对MCF-7细胞增殖的抑制,提高肿瘤细胞对化疗药物的敏感性,克服耐药性的产生.
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