RNA干扰对乳腺癌细胞骨桥蛋白基因表达抑制的研究

目的应用RNA干扰术靶向降低乳腺癌MCF-7细胞中骨桥蛋白基因（OPN）的表达水平，研究OPN基因对乳腺癌细胞增殖和侵袭性等生物学行为的影响。方法将设计合成的骨桥蛋白OPN序列特异性小分子干扰RNA（siRNA），转染乳腺癌细胞株MCF-7，用逆转录PCR和蛋白印记杂交测OPN mRNA及蛋白水平的表达，通过生长曲线、克隆形成实验来检测细胞增殖及侵袭性情况的变化。结果OPN特异性siRNA转染后，骨桥蛋白mRNA及蛋白水平均明显下降，比色法显示转染组72h吸光度值为（0．21±0．06）与空白对照组（1．18土0．05）相比较明显受到抑制。转染组细胞克隆形成数为3．8个，较空白对照组（7．3个）及阴性对照组（7．1个）明显下降（P〈0．05）。结论乳腺癌MCF-7细胞中，针对OPN合成的siRNA能够有效地抑制骨桥蛋白的表达，从而显著抑制细胞的增殖和侵袭能力。

Study of knocking down osteopontin expression by specific siRNA in human breast carcinoma cells

Objective To study the effect of osteopontin (OPN) expression down-regulated by RNA inter-ference(RNAi) on the proliferation and invasion of breast carcinoma cell line MCF-7. Methods MCF-7 cells were transfected with the chemically synthesized small interfering RNA (siRNA). RT-PCR and Western blotting were used to quantify the mRNA and OPN protein levels. The proliferation and invasion of MCF-7 were observed by cell growth curve and colony formation, experiments. Results After being transfected by sequence-specific siRNA targe-ting OPN, the expression of OPN RNA and protein decreased in MCF-7 cells. MTT test showed that the proliferation was inhibited significantly by siRNA compared with the control groups. The number of formed colonies was decreas ed in MCF-7 cells transfected with OPN - specific siRNA compared with control groups (P < 0.05). Condusion Sequence-specific siRNA targeting OPN can effectively inhibit the expression of OPN mRNA and protein levels, and significantly diminishes the proliferation and invasion of MCF-7 cells.