Modeling and Dissecting Epigenetic Drivers of Gliomagenesis

神经胶质瘤发生的表观遗传驱动因素的建模和剖析

• 批准号: 10350834
• 负责人: Gilbert J Rahme
• 金额: $ 16.74万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10350834
• 关键词: 3-Dimensional; Advisory Committees; Affect; Automobile Driving; Award; Binding; Binding Sites; Brain Neoplasms; CCCTC-binding factor; CDKN2A gene; Cell division; Cells; Characteristics; Collaborations; Communities; CpG Island Methylator Phenotype; DNA; DNA Methylation; DNA Modification Methylases; Diffuse; Elements; Enhancers; Enzymes; Epigenetic Process; Event; Functional disorder; Gene Activation; Gene Expression; Genes; Genetic; Genome; Glioma; Gliomagenesis; Heritability; Human; Hypermethylation; In Vitro; Inherited; Institutes; International; Isocitrate Dehydrogenase; Lesion; Malignant - descriptor; Mediating; Medical; Mentors; Metabolic; Methylation; Missense Mutation; Mitotic; Modeling; Mus; Mutation; Platelet Activation; Platelet-Derived Growth Factor alpha Receptor; Primary Brain Neoplasms; Proto-Oncogenes; Recording of previous events; Research; Role; Scientist; Shapes; Site; Structure; Synteny; Testing; Tumor Suppressor Genes; Tumor Suppressor Proteins; career; cell type; epigenetic regulation; epigenome; genome-wide; improved; in vivo; in vivo Model; inhibitor; methylation pattern; multimodality; mutant; novel therapeutic intervention; oligodendrocyte progenitor; programs; promoter; stem cells; tumor; tumor initiation

PROJECT SUMMARY Diffuse gliomas are incurable brain tumors despite aggressive therapies 1–4. Understanding the mechanisms that initiate gliomas is a critical step towards improving therapies. The majority of diffuse gliomas are driven by missense mutations in Isocitrate Dehydrogenase 1 (IDH1) which cause genome-wide DNA hypermethylation, a characteristic of IDH1mut gliomas 4–7. DNA hypermethylation may promote gliomagenesis by silencing tumor suppressor genes 8. Alternatively, DNA hypermethylation may also promote gliomagenesis by activating proto- oncogenes through disruption of CTCF insulator sites 9–13. CTCF insulator sites define the three-dimensional shape of the genome by dictating the boundaries of topologically associated domains (TADs) 14,15. Enhancers and promoters can interact when located in the same TAD but not across different TADs 14. IDH1mut gliomas are characterized with CpG hypermethylation around CTCF sites, effectively leading to insulator disruption and TAD reorganization, allowing for the activation of the platelet-derived growth factor receptor α (PDGFRA) proto- oncogene 16. Importantly, the effects of TAD disruption critically depend on the enhancers in the affected loci, which are strongly cell-type specific 12,14,17–19. I present preliminary evidence that an insulator downstream PDGFRA is disrupted in IDH1mut gliomas, allowing for aberrant interactions with a strong enhancer in a neighboring TAD, driving PDGFRA expression. This glioma enhancer is also active in oligodendrocyte-progenitor cells (OPCs), candidate cells-of-origin for glioma 20–23. I also present evidence that robust hypermethylation of the CDKN2A promoter silenced this tumor suppressor in IDH1mut gliomas. These strongly methylated elements can be maintained throughout cell division by DNA methyltransferase 1 (DNMT1), which maintains methylation patterns through cell replication 24–26. The objectives of this proposal are to (1) Model glioma-relevant epigenetic lesions at the PDGFRA and CDKN2A loci in OPCs, (2) Test whether disruption of the PDGFRA insulator and CDKN2A is sufficient to initiate gliomagenesis from OPCs in vivo, and (3) Test whether the epigenetic lesions at the PDGFRA insulator and CDKN2A promoter are mitotically propagated as tumor drivers in glioma. These studies will uncover whether mitotically heritable epigenetic lesions are sufficient to initiate diffuse gliomas. Dr. Bernstein is an internationally respected leader in epigenetics and an outstanding mentor with a history of successful trainees. The proposed research will be carried out at MGH, a research and medical institute, part of a vibrant collaborative community that includes the Broad Institute and other local institutes. A research advisory committee of world-class scientists will provide guidance: Drs. Suzanne Baker, Mario Suvà, and Miguel Rivera. Critical aspects of the research will be completed through collaborations with Drs. Chao Cheng and Mario Suvà. The K99/R00 award will provide me with the best opportunity to succeed in my career and will be invaluable for a successful transition to independence, allowing me to start an ambitious research program.

项目摘要 弥漫性神经胶质瘤是无法治愈的脑肿瘤，尽管积极的治疗1-4。了解这些机制， 引发神经胶质瘤是改进治疗关键步骤。大多数弥漫性胶质瘤是由 异柠檬酸脱氢酶1（IDH 1）中的错义突变导致全基因组DNA超甲基化， IDH 1 mut神经胶质瘤的特征4-7. DNA超甲基化可能通过沉默肿瘤促进胶质瘤生成 抑制基因8.另外，DNA超甲基化也可能通过激活原核细胞而促进胶质瘤的发生。 通过破坏CTCF绝缘子位点9-13的癌基因。CTCF绝缘子位置定义了三维 通过规定拓扑相关域（TADs）的边界来确定基因组的形状14，15。增强剂 并且启动子在位于相同的TAD 14中但不在不同的TAD 14之间时可以相互作用。IDH 1 mut胶质瘤是 其特征在于CTCF位点周围的CpG超甲基化，有效地导致绝缘子破坏和细胞凋亡。 重组，允许血小板衍生生长因子受体α（PDGFRA）原- 癌基因16.重要的是，干扰的效果关键取决于受影响基因座中的增强子， 其是强细胞类型特异性的12，14，17 -19。我提出初步证据证明下游的绝缘体 PDGFRA在IDH 1 mut神经胶质瘤中被破坏，允许与一个强增强子的异常相互作用。 邻近的细胞，驱动PDGFRA表达。这种胶质瘤增强子在少突胶质细胞祖细胞中也有活性。 细胞（OPC），神经胶质瘤的候选起源细胞20-23。我还提出证据表明， CDKN 2A启动子沉默IDH 1 mut胶质瘤中的这种肿瘤抑制因子。这些高度甲基化的元素 可以通过DNA甲基转移酶1（DNMT 1）在整个细胞分裂过程中维持，DNMT 1维持甲基化 通过细胞复制的模式24-26.本提案的目标是（1）模型胶质瘤相关的表观遗传 （2）检测OPCs中PDGFRA和CDKN 2A基因座的破坏是否与PDGFRA绝缘子和CDKN 2A基因座的破坏有关。 CDKN 2A足以在体内启动来自OPCs的胶质瘤形成，以及（3）测试在OPCs中的表观遗传病变是否与OPCs的表观遗传病变相关。 PDGFRA绝缘子和CDKN 2A启动子在神经胶质瘤中作为肿瘤驱动因子进行有丝分裂增殖。这些 研究将揭示有丝分裂遗传的表观遗传损伤是否足以引发弥漫性神经胶质瘤。 博士伯恩斯坦是表观遗传学的国际知名领导者，也是一位杰出的导师， 成功的学员。拟议的研究将在MGH进行，MGH是一家研究和医学机构， 一个充满活力的合作社区，包括布罗德研究所和其他地方研究所。研究咨询 一个由世界级科学家组成的委员会将提供指导：苏珊娜·贝克、马里奥·苏瓦和米格尔·里维拉博士。 该研究的关键方面将通过与Chao Cheng和Mario Suvà博士的合作完成。 K99/R 00奖将为我的职业生涯提供最佳的成功机会，对于 成功地过渡到独立，使我能够开始一个雄心勃勃的研究计划。