MG132诱导HepG_2细胞凋亡及其对p53表达的影响

目的观察蛋白酶体抑制剂MG132对人肝癌细胞系HepG2的致凋亡作用及其对凋亡相关基因p53蛋白表达的影响。方法采用多个浓度(2,5,10μmol/L)的蛋白酶体抑制剂MG132处理HepG2细胞;流式细胞术和Hoechst荧光染色检测细胞凋亡;免疫细胞化学检测HepG2细胞p53蛋白含量。结果对照组HepG2细胞凋亡率低于5%,在2,5,10μmol/LMG132作用下,细胞凋亡率分别为42.9%,66.1%和72.8%,MG132诱导HepG2细胞凋亡具有剂量—效应关系。经Hoechst荧光染色可见细胞染色质浓缩等凋亡改变。免疫组织化学检测HepG2细胞p53蛋白表达水平增高。结论蛋白酶体抑制剂MG132能够诱导HepG2细胞凋亡,其作用呈剂量—效应关系;p53蛋白表达增加与MG132抑制泛素—蛋白酶体系统降解细胞内p53蛋白有关。

Expression of p53 in the apoptosis of human hepatocelluar cancer cell line HepG2 induced by proteasome in -hibitor MG132

Objective To study the effect on expression of p53 in the apoptosis of human hepatocelluar cancer cells(HepG2) induced by proteasome inhibitor MG132 . Methods HepG2 cells were treated with MG132 (2,5,10 μmol/L) for 24 hours. The apoptotic cells were determined by flow cytometric analysis and Hoechst 33258 fluorescence staining. p53 protein expression was detected by immunohistochemistry. Results The results showed that the increase of the degree of HepG2 cell apoptosis was concentration-dependent. Marked morphological changes of cell apoptosis including chromosome condensation and nuclear fragmentation were observed very clearly by Hoechst 33258 fluorescence staining especially after the cells treated with MG132 for 24 h.Immunohistochemistry showed that p53 protein expression was increased in treatment group. Conclusion Proteasome inhibitor MG132 could induce HepG2 cell apoptosis by inhibiting ubiquitin-proteasome pathway(UPP) activity , up-regulating the protein expression of p53.