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: 10877343
• 负责人: Gilbert J Rahme
• 金额: $ 24.9万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10877343
• 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; Combined Modality Therapy; 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; 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; Proliferating; Proto-Oncogenes; Recording of previous events; Research; Role; Scientist; Shapes; Site; Structure; Synteny; Testing; Tumor Suppressor Genes; Tumor Suppressor Proteins; aggressive therapy; career; cell type; epigenetic regulation; epigenome; genome-wide; improved; in vivo; in vivo Model; inhibitor; methylation pattern; 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.

项目总结 弥漫性胶质瘤是无法治愈的脑瘤，尽管采取了积极的治疗方法1-4。 启动神经胶质瘤是改善治疗方法的关键一步。大多数弥漫性胶质瘤是由 异柠檬酸脱氢酶1(IDH1)的错义突变导致全基因组DNA超甲基化 IDH1突变胶质瘤的特征4-7.DNA超甲基化可能通过沉默肿瘤促进胶质瘤的形成 抑癌基因8。或者，DNA超甲基化也可能通过激活原-DNA促进胶质瘤的发生。 癌基因通过破坏CTCF绝缘子位置9-13。CTCF绝缘子位置定义三维 通过规定拓扑相关结构域(TADS)的边界来塑造基因组的形状(TADS)14，15.增强子 当启动子位于相同的TAD但不能跨越不同的TAD时，启动子可以相互作用14。 以CTCF位点周围的CpG超甲基化为特征，有效地导致绝缘子破裂和TAD 重组，允许激活血小板衍生生长因子受体α(PDGFRA)原- 重要的是，TAD干扰的效果严重依赖于受影响基因的增强子， 它们具有强烈的细胞类型特异性12，14，17-19。我提出的初步证据表明，下游的绝缘子 在IDH1突变的胶质瘤中，PDGFRA被破坏，允许与一个强大的增强子在 邻近TAD，驱动PDGFRA表达。这种胶质瘤增强子在少突胶质细胞前体细胞中也是活跃的。 细胞(OPC)，胶质瘤的候选起源细胞20-23。我还提出了证据表明，强效甲基化 在IDH1mut胶质瘤中，CDKN2A启动子沉默了这种肿瘤抑制基因。这些高度甲基化的元素 可以通过DNA甲基转移酶1(DNMT1)维持在细胞分裂过程中，DNA甲基转移酶1维持甲基化 通过细胞复制24-26形成图案。该方案的目标是(1)建立与胶质瘤相关的表观遗传学模型 OPC中PDGFRA和CDKN2A基因座的损伤，(2)检测PDGFRA绝缘子和 CDKN2A足以在体内启动OPC的胶质瘤形成，以及(3)测试表观遗传损伤是否在 PDGFRA绝缘体和CDKN2A启动子作为肿瘤驱动因子在胶质瘤中有丝分裂地传播。这些 研究将揭示可有丝分裂遗传的表观遗传学病变是否足以引发弥漫性胶质瘤。 伯恩斯坦博士是表观遗传学在国际上备受尊敬的领导者，也是一位杰出的导师，拥有 成功的实习生。拟议的研究将在MGH进行，这是一家研究和医疗机构，是 一个充满活力的合作社区，其中包括布罗德研究所和其他当地机构。研究咨询 世界级科学家委员会将提供指导：苏珊娜·贝克博士、马里奥·SUV ka博士和米格尔·里维拉博士。 这项研究的关键方面将通过与赵成博士和马里奥SUV ka博士的合作来完成。 K99/R00奖将为我提供在职业生涯中取得成功的最佳机会，对 向独立的成功过渡，让我开始了一项雄心勃勃的研究计划。