目的 研究硒-甲基硒代半胱氨酸(MSC)对肝癌SMMC-7721细胞株抑制及凋亡的作用,探讨其分子机制.方法 试验分空白对照组和MSC组(细胞培养体系中加入MSC).MTT法观察细胞增殖；流式细胞术检测细胞周期及凋亡率；透射电镜观察细胞超微结构的改变;琼脂糖凝胶电泳法观察DNA的“梯状”条带；Western blot方法检测凋亡诱导因子(AIF)蛋白表达.结果 随着MSC浓度和作用时间增加,细胞抑制率上升.肝癌细胞株SMMC-7721在MSC浓度为25、30、100、200μmol/L下,24 h细胞抑制率分别为(14.44±3.83)％、(21.15±0.61)％、(50.61±2.10)％、(64.25±0.87)％,48 h细胞抑制率分别为(35.97±2.08)％、(57.41±2.61)％、(74.71±1.59)％、(91.68±1.33)％(P＜0.05).MSC组细胞周期出现S期阻滞,并出现凋亡峰,50、l00μmol/L浓度的MSC干预48 h后,肝癌SMMC-7721细胞株凋亡率分别为28.46％、50.73％.MSC组细胞呈凋亡表现,核固缩、碎裂,染色质浓缩,边集.MSC 50μmol/L或100 μmol/L组培养48h后,DNA琼脂糖凝胶电泳可见典型的梯状条带；而空白对照组细胞DNA在电泳上未见梯状条带.经MSC干预后,AIF蛋白表达呈浓度依赖性增多(P＜0.05).结论 MSC对肝癌MMC-7721细胞株有抑制增殖、促进凋亡的作用.其机制可能通过调控AIF表达激活非Caspases依赖凋亡通路实现的.%Objective To study the relationship between the changes of proportion of breast cancer stem cells (BCSCs) subgroup and the resistance of aromatases inhibitors ( AIs). Methods Quantities of CD44+CD24- cells in AIs resistant human breast cancer cell line(MCF-7/AI) and its parental cell line MCF-7 were analyzed by flow cytometry, and the proportions of the two were compared. Results The average proportion of CD44+ CD24- cells in MCF-7/AI was (13. 15 ± 5. 50) %, which was significantly higher than (0. 39 ± 0. 22) % that in MCF-7 (P<0. 05). Conclusion MCF-7/Al has a higher proportion of BCSCs subgroup than MCF-7, indicating that the resistance of AIs may be associated with BCSCs and the change of BCSCs proportion may be a crucial marker for AIs resistance.
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