组蛋白去乙酰化酶抑制剂Trichostatin—A诱导人乳腺癌MCF-7细胞凋亡的机制

Mechanisms of TSA-Induced apoptosis of MCF-7 breast cancer cells

目的探讨组蛋白去乙酰化酶抑制剂Trichostatin-A（TSA）诱导肿瘤细胞凋亡的机制。方法显微镜下观察TSA作用24、48h后，小鼠NIH3T3成纤维细胞、人乳腺癌MCF-7细胞的形态学变化，采用流式细胞学方法（FCM）检测细胞凋亡情况。利用Western blot方法检测细胞周期相关蛋白Rb蛋白和凋亡相关蛋白多聚ADP核糖聚合酶（PARP）降解片段的表达。结果TSA作用后的NIH3T3细胞，生长变得缓慢，但细胞尚保持生长的活性。MCF-7细胞24、48h的凋亡率分别为（36．4±1．5）％、（67．0±2．8）％，以48h最明显。TSA作用24、48、72h后，两种细胞均出现不同程度的磷酸化Rb蛋白水平下降，MCF-7细胞中PARP发生明显的降解，48h后降解明显，72h达到最大程度。结论TSA可诱导MCF-7细胞凋亡，其机制可能通过改变肿瘤细胞核染色质的空间结构，以及阻滞细胞周期实现的。

Objective To investigate the mechanisms of apoptosis by the drug Trichostatin-A （TSA） treatment in MCF-7 breast cancer ceil line, Methods The morphological change of ceils was ob- served by microscope after NIH 3T3 ,MCF-7 cells treated with TSA for 24,48 h. Flow eytometry was used to detect the apoptosis of the ceils. The expression of poly ADP-ribose polymerase PARP was detected by Western blot. Results The growth of the NIH 3T3 ceils become very slow after treatment with TSA, but these cells still survived. Meanwhile ,the apoptotic rate of MCF-7 cells was （36.4 ± 1.5） % and （ 67.0 ± 2.8） % after treatment with TSA for 24 and 48 h, more obviously for 48 h （ P 〈 0.01 ）. The expression of phosphorylated Rb protein was decreased in the NIH3T3 and MCF-7 cells. Simultaneously, PARP degradation was observed in MCF-7 cells,more obvious at 48 h,and reached the peak at 72 h. Conclusion TSA can induce the apoptosis of tumor cell MCF-7 ,which may be related to the change in chromatin conformation and blockade of cell cycle.