HSP90功能抑制对乳腺癌细胞端粒酶和突变型P53的影响

Effect of HSP90 Function Inhibited on the Telomerase and P53 Mutant in Breast Cancer Cells

目的应用HSP90功能抑制剂格尔德霉素(geldanamycin,GA)研究HSP90功能抑制对乳腺癌细胞增殖及端粒酶活性和突变型P53表达的影响。方法培养人乳腺癌细胞株MDA-MB-435s,采用MTT法检测GA对MDA-MB-435s细胞的生长抑制作用,流式细胞术分析细胞周期,用TRAP-ELISA法检测细胞端粒酶活性,Western blot检测细胞内突变型P53蛋白表达变化。结果GA对MDA-MB-435s细胞增殖有明显抑制作用,呈时效量效依赖关系,GA作用后细胞呈现G2/M期阻滞,细胞内端粒酶活性下降,突变型P53蛋白表达明显下调。结论乳腺癌细胞中端粒酶活化和突变型P53表达与HSP90功能有关,用GA抑制HSP90功能可降低端粒酶活性和突变型P53表达,从而抑制乳腺癌细胞增殖。

Objective To investigate the effect of heat shock protein 90（Hsp90） function inhibited on the telomerase activity and P53 expression in human breast cancer cells, in which a specific inhibitor geldanamycin （GA） was used to inhibit Hsp90 function. Methods Human breast cancer cell line MDA-MB-435s was used for the study. Proliferation of MDA-MB-435s cells was measured with MTT assay. Cell cycle was analyzed by flow cytometry. The telomerase activity was measured by TRAP-ELISA assay. The protein expression of mutant P53 in cells was detected by Western blot. Results GA inhibited the proliferation of MDA-MB-435s cells on a timeand dose-depending manner. After treated with GA, MDA-MB-435s cells arrested at G2 /M phase. The telomerase activity of cells was decreasing, the expression level of mutant P53 protein in MDA-MB-435s cells was reduced obviously compared with that in control cells. Conclusion The telomerase activation and mutant P53 expression in MDA-MB-435s cells are related to HSP90 function, of which the inhibition with GA can decrease the telomerase activity and the protein expression of mutant P53, and further repress the proliferation of MDA-MB- 435s cells.