HSP90在乳腺癌细胞增殖中的作用与机制研究

Effect of heat shock protein 90 on proliferation of human breast cancer cells and its molecular mechanisms

目的:应用热休克蛋白90(HSP90)功能特异性抑制剂格尔德霉素(GA)研究HSP90在乳腺癌细胞增殖中的作用,进而探讨相关机制。方法:培养人乳腺癌细胞株MDA-MB-435 s,采用MTT法检测GA对MDA-MB-435 s细胞的生长抑制作用,流式细胞术分析细胞周期,应用W estern免疫印迹法检测细胞内Stat3磷酸化状态和突变型p53表达变化。结果:不同浓度GA对乳腺癌MDA-MB-435 s细胞有生长抑制作用,呈时效量效依赖关系,GA作用后细胞呈现G2/M期阻滞。400 nmol/L GA作用48h后,细胞内Stat3磷酸化水平明显低于对照组,同时突变型p53表达明显低于对照组。结论:抑制HSP90功能可明显抑制乳腺癌MDA-MB-435 s细胞的增殖,此与下调细胞内Stat3磷酸化水平和突变型p53表达有关。

AIM ： To investigate the effect of heat shock protein 90 （HSP90） on proliferation of human breast cancer cells by a specific inhibitor for HSP90, geldanamycin （ GA）, and to analyze its molecular mechanisms. METHODS： Human breast cancer cell line MDA- MB-435s was used as a model. Proliferation of MDA- MB-435s cell was measured with MTT assay. Cell cycle was analyzed by flow cytometry. Alteration of phosphorylated Stat3 protein and mutant p53 protein in cells was detected by Western blotting. RESULTS： Geldanamycin inhibited the proliferation of MDA - MB -435s cells in time - and dose - depending manners. After treatment with GA, MDA - MB -435s cell cycle was arrested at G2/M phase. The levels of phosphorylated protein Stat3 and mutant p53 protein in MDA -MB -435s cells were reduced obviously by 55% and 48% respectively after 48 hour treatment with GA at the concentration of 400 nmol/L, compared to control cells. CONCLUSION ： Inhibition of HSP90 function can prevent breast cancer cell proliferation significantly, which may be related to down - regnlatin of the phosphorylated Stat3 protein and mutant p53 protein in the cells.