SIRT1去乙酰化酶抑制剂引起人乳腺癌MCF-7耐药细胞凋亡的机制  

Mechanism of apoptosis induced by SIRT1 deacetylase inhibitors in human breast cancer MCF-7 drug-resistant cells

作　　者：李咏[1] 徐榕[1] 张秀敏[1] 李电东[1] 何琪杨[1] 

机构地区：[1]中国医学科学院北京协和医学院医药生物技术研究所,北京100050

出　　处：《药学学报》2008年第10期1003-1010,共8页Acta Pharmaceutica Sinica

基　　金：国家自然科学基金资助项目(30672482)

摘　　要：研究SIRT1去乙酰化酶抑制剂引起人乳腺癌MCF-7耐多柔比星(doxorubicin,DOX)细胞及其敏感细胞凋亡的机制。MTT法检测细胞生长抑制作用;Western blotting方法检测蛋白表达;DNA特异染料Hoechst 33342染色检测染色质凝集;Annexin V检测细胞凋亡;流式细胞仪测定细胞周期分布。结果表明,SIRT1去乙酰化酶抑制剂烟酰胺(nicotinamide,NAM)和Sirtinol对人乳腺癌细胞MCF-7敏感和耐药细胞表现出相同的生长抑制作用,但没有增强DOX活性的作用。NAM使MCF-7和MCF-7/DOX细胞阻滞在G2/M期。50 mmol.L-1NAM作用MCF-7细胞后,激活caspase凋亡通路,出现PARP、caspase-6、-7、-9切割片段,并且染色质发生凝集和Annexin V阳性细胞。而在MCF-7/DOX耐药细胞中,NAM作用24 h后,才开始出现PARP、caspase-6、-7切割片段,48 h后明显增加,可以检测到较多的细胞出现染色质凝集和Annexin V阳性细胞。SIRT1去乙酰化酶抑制剂对人乳腺癌MCF-7耐药细胞和敏感细胞均有相似的抑制作用,无交叉耐药性,其作用通过激活caspase凋亡通路实现。The mechanism of apoptosis induced by SIRT1 deacetylase inhibitors in both human breast cancer MCF-7 and MCF-7 doxorubicin-resistant ceils was studied. MTT assay was used to detect growth- inhibitory effect on the cells. Protein expression was detected by Western blotting. Chromatin condensation was detected by a fluorescent microscope after Hoechst 33342 staining. Cell cycle distribution was analyzed with flow cytometry. Apoptotic cells were detected with Annexin V staining. Nicotinamide （NAM） and Sirtinol, two SIRT1 deacetylase inhibitors, exhibited the similar growth-inhibitory effects on MCF-7/DOX cells and MCF-7 cells, but no potentiation of DOX activities. The arrest at G2/M phase was detected by flow cytometry in both MCF-7 and MCF-7/DOX cells after NAM treatment. Activation of caspase pathway in MCF-7 cells, such as the cleavages of PARP, caspase-6, -7, -9, were observed after exposure to NAM 50 mmol·L^-1, accompanied by the occurrence of chromatin condensation and Annexin V positive cells. However, the cleavages of PARP, caspase-6 and -7 in MCF-7/DOX cells delayed after exposure to NAM for 24 h and obviously increased at 48 h with appearance of chromatin condensation and Annexin V positive cells. SIRT1 deacetylase inhibitors show no cross resistance to MCF-7 drug-resistant cells, and the similar growth-inhibitory actions of them to MCF-7 sensitive and drug-resistant cells by which it is mediated by activation of apoptotic caspase pathway.

关 键 词：SIRT1去乙酰化酶抑制剂 多药耐药性 细胞凋亡 人乳腺癌MCF-7细胞 

分 类 号：R737.9[医药卫生—肿瘤]