选择性 BCL-XL 抑制与 MLN8237 联合促进髓母细胞瘤和儿童脑胶质瘤细胞凋亡。
Selective BCL-XL inhibition promotes apoptosis in combination with MLN8237 in medulloblastoma and pediatric glioblastoma cells.
机构信息
Translational Neuro-Oncology Group, Leeds Institute of Cancer and Pathology, University of Leeds, St James's University Hospital, Leeds, UK.
Flow Cytometry Facility, Leeds Institute of Cancer and Pathology, University of Leeds, St James's University Hospital, Leeds, UK.
出版信息
Neuro Oncol. 2018 Jan 22;20(2):203-214. doi: 10.1093/neuonc/nox134.
BACKGROUND
CNS tumors, including medulloblastoma and pediatric glioblastoma (pGBM) account for the majority of solid pediatric malignancies. There remains an unmet need to identify novel treatment approaches in poor prognosis and relapsed pediatric brain tumors, where therapeutic options are limited. Small-molecule B-cell lymphoma 2 (BCL-2) family inhibitors may enhance tumor cell killing when combined with conventional and targeted chemotherapeutic agents. We investigated the effect of disrupting BCL-2 and B cell lymphoma-extra large (BCL-XL) protein function using ABT-263, ABT-199 and WEHI-539 in medulloblastoma and pGBM cells following treatment with MLN8237, an Aurora kinase inhibitor under investigation as a novel agent for the treatment of malignant brain tumors.
METHODS
Tumor cell growth and viability were determined by MTT/WST-1 assays and flow cytometry. Effects on cell phenotype, cell cycle progression, and ploidy were determined by live cell imaging and DNA content analysis. Apoptosis was determined by annexin V/propidium iodide staining and time-lapse microscopy and confirmed by measuring caspase-3/7 activity and western blotting and by short interfering RNA (siRNA) knockdown of BCL-2 associated X protein/BCL-2 antagonist killer (BAX/BAK).
RESULTS
ABT-263, in combination with MLN8237, reduced mitotic slippage and polyploidy and promoted the elimination of mitotically defective cells via a BAX/BAK-dependent, caspase-mediated apoptotic pathway. The BCL-XL antagonist, WEHI-539, significantly augmented tumor cell killing when used in combination with MLN8237, as well as sensitized resistant brain tumor cells to a novel BAX activator, SMBA1. In addition, siRNA-mediated knockdown of BCL-XL sensitized pGBM and medulloblastoma cells to MLN8237 and mimicked the effect of combination drug treatment.
CONCLUSION
Selective small-molecule inhibitors of BCL-XL may enhance the efficacy of MLN8237 and other targeted chemotherapeutic agents.
背景
中枢神经系统肿瘤，包括髓母细胞瘤和儿童脑胶质瘤（pGBM），占儿童实体恶性肿瘤的大部分。在预后不良和复发的儿童脑肿瘤中，治疗选择有限，仍然需要寻找新的治疗方法，这些肿瘤的治疗选择有限。小分子 B 细胞淋巴瘤 2（BCL-2）家族抑制剂与传统和靶向化疗药物联合使用时，可能会增强肿瘤细胞的杀伤作用。我们研究了在使用 Aurora 激酶抑制剂 MLN8237 处理后，使用 ABT-263、ABT-199 和 WEHI-539 破坏 BCL-2 和 B 细胞淋巴瘤特大（BCL-XL）蛋白功能对髓母细胞瘤和 pGBM 细胞的影响，MLN8237 正在作为治疗恶性脑肿瘤的新型药物进行研究。
方法
通过 MTT/WST-1 测定和流式细胞术测定肿瘤细胞生长和活力。通过活细胞成像和 DNA 含量分析测定对细胞表型、细胞周期进程和倍性的影响。通过 Annexin V/碘化丙啶染色和延时显微镜确定细胞凋亡，并通过测量 Caspase-3/7 活性和 Western blot 以及通过 BCL-2 相关 X 蛋白/BCL-2 拮抗剂杀伤（BAX/BAK）的短发夹 RNA（siRNA）敲低来确认细胞凋亡。
结果
ABT-263 与 MLN8237 联合使用可减少有丝分裂滑溜和多倍体，并通过 BAX/BAK 依赖性 Caspase 介导的凋亡途径促进有丝分裂缺陷细胞的消除。BCL-XL 拮抗剂 WEHI-539 与 MLN8237 联合使用时可显著增强肿瘤细胞杀伤作用，并使新型 BAX 激活剂 SMBA1 对耐药脑肿瘤细胞敏感。此外，siRNA 介导的 BCL-XL 敲低可使 pGBM 和髓母细胞瘤细胞对 MLN8237 敏感，并模拟联合药物治疗的效果。
结论
BCL-XL 的选择性小分子抑制剂可能增强 MLN8237 和其他靶向化疗药物的疗效。
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