Chloroquine, an autophagy inhibitor, potentiates the radiosensitivity of glioma initiating cells by inhibiting autophagy and activating apoptosis

作者：Hongxing Ye, Mantao Chen, Fei Cao, Hongguang Huang, Renya Zhan, Xiujue Zheng · 发表于：BMC Neurology · 年份：2016 · DOI：10.1186/s12883-016-0700-6 · 被引用次数：128 · 研究领域：Autophagy in Disease and Therapy、Cell death mechanisms and regulation、Cancer Mechanisms and Therapy

BACKGROUND: Glioblastoma is refractory to conventional treatment, which is combined of surgery, chemotherapy and radiotherapy. Recent studies have shown that glioma initiating cells (GICs) contribute to tumorigenesis and radioresistance. Recently, other studies showed that the GICs use the autophagy as the major pathway to survive. Chloroquine, an anti-malarial chemical, is an autophagic inhibitor which blocks autophagosome fusion with lysosome and slows down lysosomal acidification. The aim of this study was to explore the mechanisms of chloroquine on the radiosensitivity of GICs. METHODS: Human glioblastoma cell lines U87 were investigated. MTT and clonogenic survival assay were used to evaluate the cell viability and survival from radiation. The formation of autophagosomes were evaluated by immunofluorescence. Annexin V-FITC/PI staining and flow cytometry were used to quantify the apoptotic cells. The expression levels of proteins were analyzed by Western blot. Cell cycle status was analyzed by checking DNA content after staining with PI. A comet assay was used to assess the DNA repair in the cells. Tumorsphere assay was used for evaluating GICs' renewal ability. RESULTS: Treatment of U87 GICs with chloroquine (10-80 nmol/L) alone inhibited the cell growth in a dose-dependent manner. A dose of chloroquine (20 nmol/L) obviously enhanced the radiation sensitivity of U87 GICs., we found more punctate patterns of microtubule-associated protein LC3 immunoreactivity in radiation...