细胞周期蛋白激酶抑制剂诱导尤文肉瘤细胞凋亡作用的机制

目的探讨小分子细胞周期蛋白激酶抑制剂flavopiridol（FP）尤文肉瘤细胞株RD-ES凋亡诱导作用及其调控机制。方法FP作用RD-ES细胞后，光学显微镜观察其形态变化，MTT法测定FP对细胞增殖的抑制率；流式细胞仪检测细胞凋亡；Western blot检测bcl-2，bax，mcl-l和caspase-8的蛋白表达变化。结果MTT实验显示FP对尤文肉瘤RD-ES细胞增殖有抑制作用，其抑制效应具有时间及浓度依赖的特点，流式细胞计数分析表明FP可诱导细胞凋亡，免疫印迹检测显示FP对bcl-2及bax的表达无影响，但细胞凋亡抑制基因mcl-1活性型caspase-8的表达被上调。结论FP可诱导尤文肉瘤细胞株凋亡，其作用不依赖于bcl-2基因的变化，mcl-1基因表达的抑制及caspase-8路径的激活可能为其机制之一。

Study on CDKI-induced apoptosis and its regulatory mechanism in ewing sarcoma

Objective To investigate the apoptotic induction effect of cyclin dependent kinase inhibitor (CDKI) on Ewing Sarcoma cell lines RD-ES and its regulatory mechanism. Methods The effect of flavopiridol on proliferation of RD-ES cells was observed by MTT assay. Detection of apoptosis and cell cycle analysis were performed with flow cytometry. The expression of bcl-2, bax, mcl-1 and caspase-8 were analyzed by Western blot. Results Flavopiridol inhibits the proliferation of RD-ES cells in dosage and time-dependent manner and induces apoptosis. Western blot showed that the expression of bcl-2 had no significant differences as compared with control group, but the down-regulation of mcl-1 and the increased active caspase-8 were detected after addition of flavopiridol. Conclusion Flavopiridol inhibits the proliferation of RD-ES cell line in the dose and time dependent manner and induces apoptosis which is not bcl-2 dependent. The inactivation of mcl-1 gene and the activation of caspase-8 may be the role of this induction.