Bax基因的过表达上调HCC-9204细胞系对阿霉素的敏感性

目的 探讨Bax基因的过表达是否能够调节HCC-9204细胞系对阿霉素的敏感性。方法 采用一种可诱导性表达系统,MT-Ⅱ调节系统,在外加锌离子（ZnSO4,100μmol/L）的条件下,诱导Bax基因过表达。以克隆形成实验来判断Bax是否能够降低阿霉素处理后肿瘤细胞的克隆存活率,以MTT实验来反映细胞活力的改变,凋亡性细胞死亡的鉴定是通过形态学标准并结合TUNEL和细胞周期的分析加以证实。结果 阿霉素能够显著诱导HCC-9204细胞发生凋亡。TUNEL染色显示典型的凋亡特征如新月体样或环状染色体边集于核膜,胞浆皱缩并且“发泡”,流式细胞仪分析显示,在处理后24h出现显著的亚二倍体峰,Bax能够显著降低阿霉素处理组的克隆存活率,Bax也能够降低药物处理后的细胞活力,呈时间依赖性。结论 Bax基因的过表达能够增加HCC-9204对阿霉素杀伤作用的敏感性。

Overexpression of Bax up-regulates the sensitivity of HCC-9204 cell apoptosis induced by adriamycin

OBJECTIVE: To investigate whether Bax could regulate the sensitivity of human HCC-9204 cells to adriamycin. METHODS: Overexpression of Bax was induced through inducible system and MT-II regulatory system, with addition of ZnSO(4) (100 micro mol L(-1)) as external inducer. Stable transfecting inducible expression vector containing Bax gene was performed. Apoptotic cells were measured by morphological criteria, and detection of apopto tic DNA fragmentation by TUNEL assay and flow cytometry. The ability of Bax to lower clonogenic cell survival rate was studied by colony-forming assay, while decrease of cell viability was assessed by MTT assay. RESULTS: HC-9204 cells treated with adriamycin (20 micro mol/L) showed extensive cell death with nucleus fragmentation detected by TUNEL assay. FACS analysis showed a significant sub-G(1) peak and apoptosis in 31% cells 24 hr after treatment. Bax was able to significantly decrease clonogenic survival rate in adriamycin treatment group, showing time dependence. Bax could selectively sensitize HCC-9204 cells to cell death induced by DNA damaging agent-adriamycin. CONCLUSION: Overexpression of Bax is able to sensitize HCC-9204 cell apoptosis induced by a driamycin.