siRNA干扰Mad2蛋白的表达对乳腺癌MCF-7细胞紫杉醇药物敏感性的影响

目的研究纺锤体检测点蛋白Mad2对乳腺癌细胞MCF-7紫杉醇敏感性的影响。方法运用小片段干扰RNA技术下调MCF-7细胞中Mad2蛋白的表达，经不同浓度的紫杉醇药物浓度处理，通过细胞术检测细胞周期分布，MTY法检测细胞存活率的变化，RT—PCR及Western印迹法检测相关蛋白的表达改变情况。结果siRNA可以特异性干扰MCF-7细胞中Mad2蛋白水平的表达，同时显著降低紫杉醇诱导细胞发生有丝分裂阻滞的比例，导致CyclinB1的表达下调，凋亡率降低；并且Mad2表达下调后，MCF-7细胞中黏附分子E-cadherin的表达量也降低。结论Mad2在紫杉醇诱导MCF-7细胞发生有丝分裂周期阻滞中发挥重要作用，进而影响细胞对紫杉醇的敏感性，同时细胞黏附分子E—cadherin可能参与这一过程的发生。

Effect of Mad2-specific iRNA on the Paclitaxel Sensitivity in MCF-7 Cells

Objective To explore the possible mechanism of Mad2 in the paclitaxel sensitivity in MCF-7 cells. Methods siRNA was used to knock down Mad2 expression level specially. After the treatment with different paclitaxel concentrations to MCF-7 cells, the cell cycle and apoptosis rate were tested by flow cytometry and MTF. RT-PCR and Western blotting were applied to assay the protein expression levels. Results Mad2 level was knocked down efficiently by siRNA. Cyclin B1 level was decreased, which caused MCF-7 cells to escape from G2/M arrest followed by the paelitaxel sensitivity reduction. E-eadherin level was also decreased in Mad2-siRNA MCF-7 cells. Conclusion Mad2 is important to keep the paclitaxel sensitivity in MCF-7 cells by blocking cells in GJM phase. E-cadherin may mediate this process in MCF-7 cells.