Evaluating ADGRB3 as a tumor suppressor epigenetically silenced in WNT medulloblastoma

评估 ADGRB3 作为 WNT 髓母细胞瘤中表观遗传沉默的肿瘤抑制因子

• 批准号: 10599504
• 负责人: ERWIN G VAN MEIR
• 金额: $ 2.6万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10599504
• 关键词: Adhesions; Animals; Binding Proteins; Brain; Brain Stem; CTNNB1 gene; Cell Culture Techniques; Cell Proliferation; Cell model; Cells; Cerebellum; Child; Chromatin; Data; Development; Development Plans; Dorsal; EZH2 gene; Epigenetic Process; Experimental Models; Family; Funding; Gene Activation; Gene Expression; Gene Silencing; Human; Intellectual functioning disability; Knockout Mice; Knowledge; Lead; Lip structure; MBD2 protein; Malignant Neoplasms; Malignant neoplasm of central nervous system; Mentors; Morbidity - disease rate; Mus; Neuraxis; Neurologic; Oncogenic; Operative Surgical Procedures; Orphan; Patients; Pediatric Neoplasm; Physiological; Predisposition; Property; Public Health; Radiation therapy; Repression; Research; Role; Secondary to; Signal Transduction; Survival Rate; Testing; Therapeutic; Tumor Suppressor Proteins; anti-cancer therapeutic; base; beta catenin; career development; cell growth; chemotherapy; developmental neurobiology; epigenetic silencing; epigenetic therapy; histone methyltransferase; medulloblastoma; mutant; nerve stem cell; novel; novel therapeutic intervention; novel therapeutics; parent grant; physically handicapped; promoter; receptor; restoration; seven-transmembrane G-protein-coupled receptor; tumor; tumor growth; tumorigenic

RESEARCH, MENTORING, AND CAREER DEVELOPMENT PLAN: RESEARCH PLAN: Project Summary/Abstract of Funded Parent Grant: There is an urgent need to develop novel therapies for patients with medulloblastoma (MB), the most common malignant central nervous system (CNS) tumor in children. Current treatments include surgery, radiotherapy, and chemotherapy and result in 5-year survival rates of 40-90% depending on subtype. However, children suffer important morbidity secondary to treatment, including neurological, intellectual and physical disabilities. The overall purpose of the present project is to investigate the role of the ADGRB3 receptor in susceptibility of cerebellar transformation, and explore new therapies for MB based on the related mechanisms. ADGRB3 is an orphan seven transmembrane G protein-coupled receptor (GPCR) specifically expressed in the brain, and belonging to the adhesion-type sub-family. Our new preliminary data show that ADGRB3 expression is significantly reduced in patients with MBs of the WNT group, and the promoter is epigenetically silenced, suggesting that ADGRB3 loss may facilitate WNT-MB formation. We present evidence for the involvement of methylated CpG binding protein MBD2 and histone methyltransferase EZH2 in switch to a silent chromatin. Moreover, we show that reactivation of ADGRB3 can reduce cell proliferation and tumor growth, supporting a tumor suppressive role. To test this in the physiological setting, we generated ADGRB3 knockout (KO) mice, which we plan to cross with mice expressing mutant b-catenin in neural progenitors of the rhombic lip and dorsal brainstem, which are the cells of origin of WNT-MB. Based on these results, we hypothesize that ADGRB3 is a tumor suppressor in the cerebellum and that restoration of its expression with epigenetic therapy may represent a novel therapeutic intervention for children with WNT-MB. To test our hypothesis, we propose the following aims: (i) identify and target the epigenetic mechanism(s) underlying ADGRB3 gene silencing in WNT-MB, (ii) determine whether and how restoration of ADGRB3 expression can inhibit MB cell growth, oncogenic signaling and tumorigenic properties, and (iii) determine whether loss of ADGRB3 gene expression in the background of oncogenic Ctnnb1 activation predisposes mice to cerebellar transformation and MB tumor development. These studies are important as they increase our knowledge about developmental neurobiology in the CNS, and may lead to the development of novel therapeutic approaches for patients with medulloblastoma.

研究、辅导和职业发展课程： 研究报告： 项目摘要/资助家长补助金摘要： 目前迫切需要为髓母细胞瘤（MB）患者开发新的治疗方法， 儿童中枢神经系统恶性肿瘤目前的治疗方法包括手术、放疗、 和化疗，根据亚型，5年生存率为40-90%。然而， 严重的继发于治疗的疾病，包括神经、智力和身体残疾。的 本项目的总体目的是研究ADGRB 3受体在以下疾病易感性中的作用： 小脑转化，并根据相关机制探索MB的新疗法。ADGRB 3是一种 孤儿七跨膜G蛋白偶联受体（GPCR），在脑中特异性表达，和 属于粘附型亚家族。我们的新的初步数据表明，ADGRB 3表达是 在WNT组的MB患者中显著降低，并且启动子在表观遗传学上沉默， 这表明ADGRB 3损失可能促进WNT-MB形成。我们提供的证据表明 甲基化的CpG结合蛋白MBD 2和组蛋白甲基转移酶EZH 2转变为沉默的染色质。 此外，我们发现ADGRB 3的重新激活可以减少细胞增殖和肿瘤生长，支持了对肿瘤的治疗。 肿瘤抑制作用。为了在生理环境中测试这一点，我们产生了ADGRB 3敲除（KO）小鼠， 我们计划将其与在菱形唇和背侧的神经祖细胞中表达突变的b-连环蛋白的小鼠杂交， 脑干，其是WNT-MB的起源细胞。基于这些结果，我们假设ADGRB 3是一种 小脑中的肿瘤抑制因子，通过表观遗传治疗恢复其表达可能代表 一种治疗WNT-MB儿童的新型干预措施。为了验证我们的假设，我们提出以下建议 目的：（i）鉴定和靶向WNT-MB中ADGRB 3基因沉默的表观遗传机制，（ii） 确定ADGRB 3表达的恢复是否以及如何抑制MB细胞生长、致癌信号传导 和致瘤特性，以及（iii）确定在肿瘤背景下ADGRB 3基因表达的丧失是否 致癌Ctnnb 1激活使小鼠容易发生小脑转化和MB肿瘤发展。这些 研究很重要，因为它们增加了我们对中枢神经系统发育神经生物学的了解，并且可能 从而为髓母细胞瘤患者开发新的治疗方法。