Mcl-1在胆盐（GCDA）诱导的肝癌细胞耐药中的作用

目的：探讨抗凋亡蛋白Mcl-1在GCDA诱导的肝癌细胞耐药中的作用及其机制。方法：培养3种肝癌细胞系，用免疫荧光法和Western blot技术检测Mcl-1的表达；GCDA±CYC处理HepG2细胞，采用Western blot技术检测Mcl-1的半衰期变化；用抗癌药物Irinotecan与GCDA对HepG2细胞进行处理，采用MTT法和Western blot技术分别检测细胞增殖抑制率和Mcl-1的表达变化；用RNA干扰技术下调Mcl-1，检测化疗药物对HepG2细胞的敏感性。结果：Mcl-1在肝癌细胞中广泛表达；GCDA能延长Mcl-1的半衰期至6h以上，并明显减弱化疗药物对抗凋亡蛋白Mcl-1的抑制作用，降低癌细胞的药物敏感性；RNA干扰下调Mcl-1能增加癌细胞的药物敏感性。结论：胆盐（GCDA）能诱导HepG2细胞产生耐药性，其作用机制可能是通过延长Mcl-1半衰期增加其蛋白稳定性和抗凋亡作用来促使肝癌细胞抗药的。

Role of Mcl-1 in Bile Salt (GCDA)-induced Chemoresistance of Hepatocellular Carcinoma Cells

Objective: To study the role of anti-apoptotic protein Mcl-1 in bile salt (GCDA)-induced chemoresistance of hepatocellular carcinoma cells. Methods: Three HCC cell lines were cultured in CO2 incubator. Expression of Mcl-1 was analyzed by immunofluorescence and Western blot. HepG2 cells were treated by GCDA±CYC or Irinotecan±GCDA. Protein expression and cell viability were assessed by Western blot and MTT, respectively. Drug sensitivity was detected after down-regulation of Mcl-1 by RNA interference in HepG2 cells.Results: Mcl-1 protein is extensively expressed in HCC cells. GCDA prolongs half-life of Mcl-1 from 2-3h to more than 6h and reduces inhibitory action of Irinotecan to Mcl-1. Down-regulation of Mcl-1 by RNA interference can enhance drug sensitivity of HepG2 cells. Conclusion: Bile salt (GCDA) can induce chemoresistance of HepG2 cells. This occurs by increasing protein stability and anti-apoptotic activity of Mcl-1.