Blockade of Inhibitors of Apoptosis Proteins in Combination with Conventional Chemotherapy Leads to Synergistic Antitumor Activity in Medulloblastoma and Cancer Stem-Like Cells
Blockade of Inhibitors of Apoptosis Proteins in Combination with Conventional Chemotherapy Leads to Synergistic Antitumor Activity in Medulloblastoma and Cancer Stem-Like Cells
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DOI：
10.1371/journal.pone.0161299
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发表时间：
2016-08-18
期刊：
影响因子：
3.7
通讯作者：
Lui, Tai-Ngar
中科院分区：
文献类型：
--
作者：
Chen, Shu-Mei;Li, Ying-Ying;Lui, Tai-Ngar
髓母细胞瘤（MB）是小儿最常见的原发性恶性脑肿瘤。大约三分之一的MB患者死于治疗失败，一些幸存者遭受有害的副作用。因此，本研究的目的是探索新的治疗方案，以克服化疗药物耐药性或减少化疗诱导的toxicity.MethodsWe检测MB和CD 133 +MB细胞系和MB组织中的凋亡抑制蛋白（IAP）的表达，采用免疫印迹和免疫组化染色。通过MTT法、Annexin V/PI分析和caspase-3/7活性评价IAP抑制剂对MB或CD 133 + MB细胞的抗肿瘤作用。自噬通过轻链（LC）3-I向LC 3-II的转化和Cyto-ID自噬检测试剂盒来评估。ResultsMB细胞显示出比正常星形胶质细胞和正常脑组织更高的IAP表达。常规化疗药物与小分子IAP抑制剂（LCL 161或LBW 242）组合在MB细胞中显示出协同作用。联合处理通过同时激活caspase-3/7和自噬流触发MB细胞凋亡。此外，我们发现具有癌症干细胞特征的CD 133 + MB细胞显示较高水平的X连锁凋亡抑制因子（XIAP）和细胞凋亡抑制因子1/2（cIAP 1/2），结论这些结果揭示了联合治疗对MB细胞的生物学效应，并说明IAP抑制剂对CD 133+干细胞更有效。就像MB细胞一样。
BackgroundMedulloblastoma (MB) is the most common pediatric primary malignant brain tumor. Approximately one-third of MB patients succumb to treatment failure and some survivors suffer detrimental side effects. Hence, the purpose of this study is to explore new therapeutic regimens to overcome chemotherapeutic agent resistance or reduce chemotherapy-induced toxicity.MethodsWe detected the expression of inhibitors of apoptosis proteins (IAPs) in MB and CD133+MB cell lines and MB tissues using immunoblotting and immunohistochemical staining. The antitumor effects of inhibitors against IAPs on MB or CD133+ MB cells were evaluated by MTT assay, Annexin V/PI analysis, and caspase-3/7 activity. Autophagy was assessed by the conversion of light chain (LC) 3-I to LC3-II and Cyto-ID autophagy detection kit.ResultsMB cells showed higher expression of IAPs compared to normal astrocytes and normal brain tissues. Conventional chemotherapeutic agents combined with small-molecule IAP inhibitors (LCL161 or LBW242) showed a synergistic effect in MB cells. Combined treatments triggered apoptosis in MB cells through activation of caspase-3/7 and autophagic flux simultaneously. In addition, we found that CD133+ MB cells with features of cancer stem cells displayed higher levels of X-linked inhibitor of apoptosis (XIAP) and cellular inhibitor of apoptosis 1/2 (cIAP1/2), and were hypersensitive to treatment with IAP inhibitors.ConclusionsThese results shed light on the biological effects of combination therapy on MB cells and illustrate that IAP inhibitors are more effective for CD133+ stem-like MB cells.