组蛋白去乙酰化酶抑制诱导小儿神经胶质瘤中肿瘤进展关键支架蛋白的表达：以 EBP50 和 IRSp53 为例。
HDAC inhibition induces expression of scaffolding proteins critical for tumor progression in pediatric glioma: focus on EBP50 and IRSp53.
机构信息
National Institute of Health and Medical Research (INSERM) Unit 1035, MicroRNAs in Cancer and Development (miRCADE) team, Bordeaux, France.
University of Bordeaux, Bordeaux, France.
出版信息
Neuro Oncol. 2020 Apr 15;22(4):550-562. doi: 10.1093/neuonc/noz215.
BACKGROUND
Diffuse midline glioma (DMG) is a pediatric malignancy with poor prognosis. Most children die less than one year after diagnosis. Recently, mutations in histone H3 have been identified and are believed to be oncogenic drivers. Targeting this epigenetic abnormality using histone deacetylase (HDAC) inhibitors such as panobinostat (PS) is therefore a novel therapeutic option currently evaluated in clinical trials.
METHODS
BH3 profiling revealed engagement in an irreversible apoptotic process of glioma cells exposed to PS confirmed by annexin-V/propidium iodide staining. Using proteomic analysis of 3 DMG cell lines, we identified 2 proteins deregulated after PS treatment. We investigated biological effects of their downregulation by silencing RNA but also combinatory effects with PS treatment in vitro and in vivo using a chick embryo DMG model. Electron microscopy was used to validate protein localization.
RESULTS
Scaffolding proteins EBP50 and IRSp53 were upregulated by PS treatment. Reduction of these proteins in DMG cell lines leads to blockade of proliferation and migration, invasion, and an increase of apoptosis. EBP50 was found to be expressed in cytoplasm and nucleus in DMG cells, confirming known oncogenic locations of the protein. Treatment of glioma cells with PS together with genetic or chemical inhibition of EBP50 leads to more effective reduction of cell growth in vitro and in vivo.
CONCLUSION
Our data reveal a specific relation between HDAC inhibitors and scaffolding protein deregulation which might have a potential for therapeutic intervention for cancer treatment.
背景
弥漫性中线脑胶质瘤（DMG）是一种儿科恶性肿瘤，预后较差。大多数患儿在确诊后不到一年就死亡。最近，已鉴定出组蛋白 H3 的突变，并且被认为是致癌驱动因素。因此，使用组蛋白去乙酰化酶（HDAC）抑制剂（如帕比司他[PS]）靶向这种表观遗传异常是目前正在临床试验中评估的一种新的治疗选择。
方法
BH3 谱分析显示，暴露于 PS 的神经胶质瘤细胞经历了不可逆的凋亡过程，这一过程通过 Annexin-V/碘化丙啶染色得到证实。通过对 3 种 DMG 细胞系的蛋白质组学分析，我们鉴定出 PS 处理后下调的 2 种蛋白质。我们通过沉默 RNA 下调这些蛋白质的生物学效应进行了研究，还在体外和体内使用鸡胚 DMG 模型研究了与 PS 治疗的组合效应。电子显微镜用于验证蛋白质定位。
结果
支架蛋白 EBP50 和 IRSp53 经 PS 处理后上调。在 DMG 细胞系中降低这些蛋白质的表达会导致增殖和迁移、侵袭的阻断，以及凋亡的增加。在 DMG 细胞中发现 EBP50 表达在细胞质和细胞核中，证实了该蛋白的已知致癌位置。用 PS 处理神经胶质瘤细胞，以及用基因或化学方法抑制 EBP50，可导致体外和体内更有效地减少细胞生长。
结论
我们的数据揭示了 HDAC 抑制剂和支架蛋白失调之间的特定关系，这可能为癌症治疗的治疗干预提供了潜力。
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