Protective autophagy inhibits cisplatin-induced apoptosis in human breast cancer MCF-7 cells

Objective To investigate whether cispaltin induces autophagy in human breast cancer cell line MCF-7 and to identify the role of autophagy in cisplatin-induced cell apoptosis. Methods After MCF-7 cells were treated with cispatin,cell proliferation was measured using MTT assay; cell apoptosis was determined by Hoechst 33342 staining assay; quantitative analysis of autophagy after Acridine orange( AO) staining was performed using fluorescence microscopy; and LC3Ⅰ / Ⅱ,p62 and poly ADP-ribose polymerase PRAP proteins expression were detected by Western blot. Results Cell proliferation was inhibited by cisplatin in a dose-dependent and timedependent manner,and cisplatin induced condensed bright blue apoptotic nuclei in breast cancer cells in a dose-dependent manner.Simultaneously,cisplatin led to the increase of microtubule-associated protein light chain 3-Ⅱ( LC3-Ⅱ) protein,the formation of acidic vesicular organelles( AVOs) and the increase of p62 protein. The levels of LC3Ⅱ and p62 were obviously increased by combination of autophagy inhibitor chlorochine and cisplatin. Compared with cisplatin alone,the combination of autophagy inhibitor chlorochine and cisplatin significantly decreased cell viability[( 89. 17% ± 2. 56%) vs( 74. 63% ± 1. 51%),P 0. 05],moreover,PARP protein was significantly clearaged( P 0. 05). Conclusions Cisplatin-induced protective autophagy in human breast cancer MCF-7 cells. Inhibition of autophagy can promote apoptosis,and combination therapy with cisplatin and autophagy inhibitors may be a promising therapeutic strategy for breast cancer.