下调HDAC6表达对乳腺癌细胞生物学行为的影响及机制

Effect of down-regulation of HDAC6 expression on biological behavior of breast cancer cells and its mechanism

目的:探讨下调HDAC6表达对乳腺癌MCF-7细胞生物学行为的影响及其分子机制。方法:分别用HDAC6 siRNA和阴性siRNA转染乳腺癌MCF-7细胞,以未处理的MCF-7细胞为空白对照,分别用RT-PCR和Western blot方法检测细胞HDAC6与p21基因和蛋白的表达,CCK-8试剂盒和流式细胞术分别检测细胞增殖与细胞周期,并用TUNEL法检测细胞凋亡。结果:干扰效果验证结果显示,HDAC6 siRNA转染能有效降低MCF-7细胞HDAC6 mRNA和蛋白的表达(均P<0.05),而阴性siRNA无此作用(P>0.05)。与空白对照组比较,HDAC6 siRNA组细胞增殖受到明显抑制,细胞G0/G1期比例增加,S期比例减少,细胞的凋亡率明显增加(均P<0.05);阴性siRNA组无上述改变(均P>0.05)。HDAC6 siRNA组细胞p21 mRNA与蛋白的表达均较空白对照组和阴性siRNA组明显升高(均P<0.05)。结论:下调HDAC6的表达能抑制乳腺癌MCF-7细胞的增殖,诱导细胞G0/G1期阻滞,并促进细胞凋亡,其机制可能与升高p21表达有关。

Objective： To investigate the effect of down-regulation of HDAC6 expression on the biological behavior of breast cancer MCF-7 cells and the possible molecular mechanism. Methods： The breast cancer MCF-7 cells were transfected with HDAC6 siRNA or negative siRNA respectively, and the untreated MCF-7 cells were used as blank control. The gene and protein expressions of HDAC6 and p21 were determined by RT-PCR method and Western blot analysis, the cell proliferation and cell cycles were measured by CCK-8 assay and flow cytometry respectively~ and the cell apoptosis was assessed by TUNEL staining. Results： The tests for validation of the interference demonstrated that mRNA and protein expression of HDAC6 were significantly decreased after HDAC6 siRNA did not exert any effect （P〉0.05）. Compared the cell proliferation was significantly inhibited, the siRNA transfection （both P〈0.05）, while the negative with the blank control group, in HDAC6 siRNA group, ratio of cells in the G0/GI phase increased and in the S phase decreased, and the cell apoptosis rate significantly increased （all P〈0.05）, while the negative siRNA had none of the above effects （all P〉0.05）. Moreover, the gene and protein expression of p21 were significantly higher than those of the blank control group and negative siRNA group （both P〈0.05）. Conclusion： In breast cancer MCF-7 cells, down-regulation of HDAC6 expression can inhibit the cell proliferation, induce G0/G1 phase arrest and promote apoptosis, which may probably be associated with the elevation of p21 expression.