Impact of Autophagy Inhibition at Different Stages on Cytotoxic Effect of Autophagy Inducer in Glioblastoma Cells

作者：Chenguang Li, Yaohua Liu, Huailei Liu, Weiguang Zhang, Chen Shen, Kenka Cho, Xin Chen, Fei Peng, Yunke Bi, Xu Hou, Zhuowen Yang, Zhixing Zheng, Kaikai Wang, Xiaoxiong Wang, Jiakang Zhang, Zhong Chen, Huichao Zou, Xinjian Zhang, Shiguang Zhao · 发表于：Cellular Physiology and Biochemistry · 年份：2015 · DOI：10.1159/000373952 · 被引用次数：61 · 研究领域：Autophagy in Disease and Therapy、Cell death mechanisms and regulation、Ginkgo biloba and Cashew Applications

BACKGROUND/AIMS: Glioblastoma multiforme (GBM) is the most malignant primary brain tumor with a poor prognosis. Combination treatment of autophagy inducer and autophagy inhibitor may be a feasible solution to improve the therapeutic effects. However, the correlation between them is unclear. The purpose of this study was to investigate the effect of autophagy inhibition at different stages on cytotoxicity of autophagy inducers in glioblastoma cells. METHODS: Autophagy inhibition at early stage was achieved by 3-methyladenine (3-MA) or Beclin 1 shRNA. Autophagy inhibition at late stage was achieved by chloroquine (CQ) or Rab7 shRNA. Cell viability was assessed by MTT assay. Autophagy was measured using transmission electron microscopy and western blot. Apoptosis was measured using western blot and flow-cytometry. RESULTS: Inhibition of early steps of autophagy by 3-MA or Beclin 1 knockdown decreased the toxic effect of arsenic trioxide (ATO) in GBM cell lines. In contrast, blockade of autophagy flux at late stage by CQ or Rab7 knockdown enhanced the cytotoxicity of ATO, and caused accumulation of degradative autophagic vacuoles and robust apoptosis. Moreover, depletion of Beclin 1 abolished the synergistic effect of ATO and CQ by reducing autophagy and apoptosis. Combination of CQ with other autophagy inducers also induced synergistic apoptotic cell death. CONCLUSION: These results suggest that inhibition of late process of autophagy, not initial step, increases the cytotoxic e...