恶性胶质瘤定向神经元诱导分化的小分子联用策略与表观遗传学机制研究

Differentiation therapy of malignant glioma is a novel and promising therapy strategy. In our previous studies, we found that activation of cAMP signalling is able to induce differentiaiton of malignant glioma cells, which have been published in PNAS and International Journal of Cancer. However, the differentiation-inducing effect is impermanent that can’t be improved by increasing doses. To overcome the obstacle of single agent, by a chemical high throughput screening, we have confirmed that HDAC inhibitor (HDACi) cooperated with 8-CPT-cAMP to induce lasting neuronal differentiation of malignant glioma. Meanwhile, using transcriptome analysis and siRNA library screening, we have identified histone 3 (H3) acetylation, chromatin remodeling, one core component of chromatin remodeling complex Baf45c, transcriptional factors Brn2 and Olig2 play pivotal roles in neuron-fate induction. Based on data above, we plan to deeply demonstrate how 8-CPT-cAMP synergizes with HDACi to enhance the acetylation of H3 (H3-ac), how H3-ac recruits Baf45c,Brn2 and Olig2 leading to chromatin remodeling and neuron-related genes expressing. This project will not only establish a combined chemical approach for differentiation therapy of malignant glioma, but also provide a new epegenetic sight of diffentiation-inducing modulation and identify novel targets for diffentiaiton therapy.

恶性胶质瘤的诱导分化疗法，是一个具有前景的新型治疗手段。申请团队前期已证实，激动cAMP通路可诱导恶性胶质瘤细胞的分化（PNAS和Int J Cancer）。然而，此分化效应并不持久，提高诱导分化剂的剂量也不能保持分化的持久性。为了突破单一用药的局限，本项目前期通过小分子化合物库高通量筛选，发现组蛋白去乙酰化酶抑制剂可协同8-CPT-cAMP持久地定向诱导恶性胶质瘤细胞分化为成熟神经元。通过转录组学分析和siRNA文库基因敲除筛选，已鉴定组蛋白H3乙酰化、染色体重塑以及重塑复合体核心成员Baf45c、转录因子Brn2和Olig2为关键调控因素。基于此，本项目拟深入研究联合方案如何协同增强H3乙酰化、继而如何招募Baf45c、Brn2、Olig2、引起染色体重塑和神经元相关基因表达的分子机制。本研究的完成，有望为恶性胶质瘤的分化疗法提供联合小分子诱导策略，并将阐明其表观遗传学的机制和靶点。

恶性胶质瘤的诱导分化疗法，是一个具有前景的新型治疗手段。申请团队前期已证实，激动cAMP通路可诱导恶性胶质瘤细胞的分化（PNAS和Int J Cancer）。然而，此分化效应并不持久，提高诱导分化剂的剂量也不能保持分化的持久性。为了突破单一用药的局限，本项目通过小分子化合物库高通量筛选，发现组蛋白去乙酰化酶抑制剂可协同8-CPT-cAMP持久地定向诱导恶性胶质瘤细胞分化为成熟神经元；通过转录组学分析和siRNA文库基因敲除筛选，已鉴定组蛋白H3乙酰化、染色体重塑以及重塑复合体核心成员Baf45c为关键调控因素；进一步研究发现，与Baf45c高亲和的组蛋白多个位点H3K9/K14和H4K5/8/12/16乙酰化增强，这些乙酰化组蛋白通过表观遗传机制调控了细胞周期相关基因和神经元分化相关基因的表达。本项目研究成果在科学上证实表观遗传调控可以改变恶性胶质瘤细胞的生物学表型，研究中发现的小分子组合将来具有转化为抗胶质瘤治疗药物的潜能。本项目基金支持下，共发表论文4篇（论文注明本项目基金号，附件5-8），培养博士研究生2名（获得博士学位附件9和10），在国际会议交流并获得奖励（附件1-4）。本研究的完成，为恶性胶质瘤的分化疗法提供了联合小分子诱导策略，并阐明了其表观遗传学的机制和靶点。