Autophagy inhibition enhances apigenin-induced apoptosis in human breast cancer cells  

作　　者：Xuchen Cao Bowen Liu Wenfeng Cao Weiran Zhang Fei Zhang Hongmeng Zhao Ran Meng Lin Zhang Ruifang Niu Xishan Hao Bin Zhang 

机构地区：[1]National Key Laboratory of Breast Cancer Prevention and Treatment, Tianjin Medical University [2]Department of Breast Cancer Surgery of the Cancer Hospital, Tianjin Medical University [3]Department of Pathology of the Cancer Institute, Tianjin Medical University [4]Tianjin Key Laboratory of Cancer Prevention and Treatment, Tianjin Medical University

出　　处：《Chinese Journal of Cancer Research》2013年第2期212-222,共11页中国癌症研究（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant no. 81001186);the Tianjin Municipal Natural Science Foundation (Grant no. 10JCYBJ C14100,11JCZDJC28000,13JCYBJC21800)

摘　　要：Apigenin （4＇,5,7-trihydroxyflavone） is a member of the flavone subclass of flavonoids present in fruits and vegetables. The involvement of autophagy in the apigenin-induced apoptotic death of human breast cancer cells was investigated. Cell proliferation and viability were assessed by 3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyltetrazolium bromide （MTT） and clonogenic assays. Flow cytometry, fluorescent staining and Western blot analysis were employed to detect apoptosis and autophagy, and the role of autophagy was assessed using autophagy inhibitors. Apigenin dose- and time-dependently repressed the proliferation and clonogenic survival of the human breast cancer T47D and MDA-MB-231 cell lines. The death of T47D and MDA-MB-231 cells was due to apoptosis associated with increased levels of Caspase3, PARP cleavage and Bax/Bcl-2 ratios. The results from flow cytometry and fluorescent staining also verified the occurrence of apoptosis. In addition, the apigenin-treated cells exhibited autophagy, as characterized by the appearance of autophagosomes under fluorescence microscopy and the accumulation of acidic vesicular organelles （AVOs） by flow cytometry. Furthermore, the results of the Western blot analysis revealed that the level of LC3-Ⅱ, the processed form of LC3-Ⅰ, was increased. Treatment with the autophagy inhibitor, 3-methyladenine （3-MA）, significantly enhanced the apoptosis induced by apigenin, which was accompanied by an increase in the level of PARP cleavage. Similar results were also confirmed by flow cytometry and fluorescence microscopy. These results indicate that apigenin has apoptosis- and autophagy-inducing effects in breast cancer cells. Autophagy plays a cyto-protective role in apigenin-induced apoptosis, and the combination of apigenin and an autophagy inhibitor may be a promising strategy for breast cancer control.Apigenin （4＇,5,7-trihydroxyflavone） is a member of the flavone subclass of flavonoids present in fruits and vegetables. The involvement of autophagy in the apigenin-induced apoptotic death of human breast cancer cells was investigated. Cell proliferation and viability were assessed by 3-（4,5-dimethylthiazol- 2-yl）-2,5-diphenyltetrazolium bromide （MTT） and clonogenic assays. Flow cytometry, fluorescent staining and Western blot analysis were employed to detect apoptosis and autophagy, and the role of autophagy was assessed using autophagy inhibitors. Apigenin dose- and time-dependently repressed the proliferation and clonogenic survival of the human breast cancer T47D and MDA-MB-231 cell lines. The death of T47D and MDA-MB-231 cells was due to apoptosis associated with increased levels of Caspase3, PARP cleavage and Bax/Bcl-2 ratios. The results from flow cytometry and fluorescent staining also verified the occurrence of apoptosis. In addition, the apigenin-treated cells exhibited autophagy, as characterized by the appearance of autophagosomes under fluorescence microscopy and the accumulation of acidic vesicular organelles （AVOs） by flow cytometry. Furthermore, the results of the Western blot analysis revealed that the level of LC3-Ⅱ, the processed form of LC3-Ⅰ, was increased. Treatment with the autophagy inhibitor, 3-methyladenine （3-MA）, significantly enhanced the apoptosis induced by apigenin, which was accompanied by an increase in the level of PARP cleavage. Similar results were also confirmed by flow cytometry and fluorescence microscopy. These results indicate that apigenin has apoptosis- and autophagy-inducing effects in breast cancer cells. Autophagy plays a cyto-protective role in apigenin-induced apoptosis, and the combination of apigenin and an autophagy inhibitor may be a promising strategy for breast cancer control.

关 键 词：APOPTOSIS AUTOPHAGY APIGENIN breast cancer 3-methyladenine 

分 类 号：R737.9[医药卫生—肿瘤]