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: 10358481
• 负责人: ERWIN G VAN MEIR
• 金额: $ 41.66万
• 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/10358481
• 关键词: Address; Adhesions; Attenuated; Behavior; Binding; Binding Proteins; Brain; Brain Stem; CRISPR/Cas technology; CTNNB1 gene; Cell Proliferation; Cells; Cerebellar Neoplasms; Cerebellum; Child; Childhood Brain Neoplasm; Chromatin; Clinical; Clinical Trials; Cognitive; Combination Drug Therapy; CpG Islands; DNA-Binding Proteins; Data; Data Set; Development; Dorsal; EZH2 gene; Epigenetic Process; Family; G-Protein-Coupled Receptors; Gene Activation; Gene Expression; Gene Expression Profile; Gene Silencing; Genes; Growth; Hippocampus (Brain); Human; In Vitro; Intellectual functioning disability; Knockout Mice; Knowledge; Lead; Life; Lip structure; MBD2 protein; Malignant neoplasm of brain; Malignant neoplasm of central nervous system; Mediating; Methylation; Molecular Profiling; Monitor; Morbidity - disease rate; Morphogenesis; Mus; Neuraxis; Neurologic; Neurons; Neurosecretory Systems; Nude Mice; Oncogenic; Operative Surgical Procedures; Orphan; Outcome Study; PTEN gene; Pathway interactions; Patients; Pediatric Neoplasm; Pharmacology; Phosphorylation; Physiological; Predisposition; Property; Protein Methyltransferases; Protein Microchips; Radiation; Radiation therapy; Regulation; Reverse Transcriptase Polymerase Chain Reaction; Role; SHH gene; Scaffolding Protein; Secondary to; Serine; Signal Pathway; Signal Transduction; Spinal; Subgroup; Survival Rate; Survivors; Synaptic plasticity; System; Testing; Therapeutic; Therapeutic Effect; Therapeutic Intervention; Tissues; Transgenic Mice; Translations; Treatment Side Effects; Tumor Suppressor Proteins; Tumorigenicity; WNT Signaling Pathway; Xenograft procedure; antagonist; base; beta catenin; bisulfite sequencing; blood-brain barrier permeabilization; cell growth; cell transformation; chemotherapy; design; developmental neurobiology; epigenetic regulation; epigenetic silencing; epigenetic therapy; experimental study; histone methyltransferase; histone modification; in vivo; inhibitor; insight; mRNA Expression; medulloblastoma; medulloblastoma cell line; member; molecular subtypes; mutant; myogenesis; nerve stem cell; neurosurgery; novel; novel therapeutic intervention; novel therapeutics; physically handicapped; promoter; receptor; restoration; seven-transmembrane G-protein-coupled receptor; side effect; small molecule; synaptogenesis; therapeutically effective; transcriptome sequencing; tumor; tumor growth; tumorigenic; young adult

Project Summary/Abstract 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.

项目概要/摘要 迫切需要为髓母细胞瘤（MB）患者开发新疗法，髓母细胞瘤是最常见的肿瘤 儿童恶性中枢神经系统（CNS）肿瘤。目前的治疗方法包括手术、放射治疗、 和化疗，根据亚型的不同，5 年生存率为 40-90%。然而，儿童 遭受治疗后继发的严重并发症，包括神经、智力和身体残疾。 本项目的总体目的是研究 ADGRB3 受体在易感性中的作用 小脑转化，并根据相关机制探索MB的新疗法。 ADGRB3 是 孤儿七跨膜G蛋白偶联受体（GPCR）在大脑中特异性表达，以及 属于粘附型亚科。我们新的初步数据表明 ADGRB3 表达是 WNT组MBs患者明显减少，启动子表观遗传沉默， 表明 ADGRB3 丢失可能促进 WNT-MB 的形成。我们提供了参与的证据 甲基化 CpG 结合蛋白 MBD2 和组蛋白甲基转移酶 EZH2 转换为沉默染色质。 此外，我们发现 ADGRB3 的重新激活可以减少细胞增殖和肿瘤生长，支持 肿瘤抑制作用。为了在生理环境中测试这一点，我们生成了 ADGRB3 敲除 (KO) 小鼠， 我们计划将其与在菱形唇神经祖细胞中表达突变b-连环蛋白的小鼠进行杂交 背侧脑干，是 WNT-MB 的起源细胞。根据这些结果，我们假设 ADGRB3 是小脑中的肿瘤抑制因子，通过表观遗传学治疗可恢复其表达 可能代表一种针对 WNT-MB 儿童的新型治疗干预措施。为了检验我们的假设，我们提出 目标如下：(i) 识别并靶向 ADGRB3 基因沉默的表观遗传机制 WNT-MB，(ii)确定 ADGRB3 表达的恢复是否以及如何抑制 MB 细胞生长， 致癌信号和致瘤特性，以及 (iii) 确定 ADGRB3 基因表达是否丧失 在致癌 Ctnnb1 激活的背景下，小鼠易患小脑转化和 MB 肿瘤 发展。这些研究很重要，因为它们增加了我们对发育神经生物学的了解 中枢神经系统，并可能导致针对患有这种疾病的患者开发新的治疗方法 髓母细胞瘤。