Epigenetic alterations underlying tumorigenic potential of Glioblastoma Cells

胶质母细胞瘤细胞致瘤潜力的表观遗传改变

• 批准号: 8330963
• 负责人: Theresa K. Kelly
• 金额: $ 13.9万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-09 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8330963
• 关键词: Award; Behavior; Bioinformatics; Biological Assay; Brain Neoplasms; Cells; ChIP-seq; Chromatin; Chromatin Structure; Classification; Coupled; DNA; DNA Methylation; Data; Diagnosis; Effectiveness; Enhancers; Ensure; Epigenetic Process; Foundations; Future; Gene Activation; Gene Expression; Gene Expression Profile; Gene Silencing; Genes; Genetic; Genomics; Glioblastoma; Histones; Human; Hypermethylation; Individual; Institution; Lead; Learning; Malignant Neoplasms; Maps; Measures; Mentors; Mesenchymal; Methods; Modification; Monitor; Neoplasm Metastasis; Normal Cell; Nucleic Acid Regulatory Sequences; Nucleosomes; Paper; Patients; Pattern; Phase; Positioning Attribute; Proteins; Radiation; Regulation; Research; Resolution; Role; Scientist; Site; Staging; Structure; Techniques; Testing; The Cancer Genome Atlas; Therapeutic; Time; Tumor Suppressor Genes; Tumorigenicity; Variant; Work; arm; base; cancer cell; carcinogenesis; career; career development; chemotherapy; chromatin remodeling; demethylation; design; epigenomics; genome wide association study; genome-wide; histone modification; malignant breast neoplasm; nerve stem cell; neural precursor cell; novel; novel strategies; novel therapeutic intervention; promoter; relating to nervous system; research study; response; therapeutic target; treatment response; tumor; tumorigenesis; tumorigenic

DESCRIPTION (provided by applicant): Glioblastoma multiforme (GBM) is almost universally fatal with median survival of 12-18 months from the time of initial diagnosis and new therapeutic approaches are needed. Epigenetics and genetics co-operate at all stages of carcinogenesis, including in brain tumors. Epigenetic mechanisms revolve around the nucleosome, a structure comprised of a core of histone proteins and DNA, which is wrapped around the histone core. A variety of epigenetic mechanisms work together to generate chromatin states that facilitate or inhibit gene activation. These mechanisms include DNA methylation (at CpG sites), histone variants and modifications and nucleosome positioning. Genome wide studies of chromatin states have focused on individual aspects of epigenetic regulation and as a result an integrated map of epigenetic regulatory mechanisms, which together determine transcriptional state, has not been completed. Using a novel technique that I have been developing (GNOMe-seq), I will generate genome wide maps of DNA methylation and nucleosome positioning within the same DNA strand of normal human neural progenitor cells and GBM cells. This will identify aberrantly silenced genes, which require DNA demethylation in addition to chromatin remodeling for reactivation. This data will be combined with localization profiles of the H2A variant, H2A.Z. In addition to being present at important genomic regulatory regions like enhancers and insulators, H2A.Z is localized to active and poised gene promoters. Combining DNA methylation, nucleosome occupancy and H2A.Z localization data will identify which genomic loci are active, poised and silenced, thereby providing critical information detailing aberrant chromatin structures present in GBM which has important implications for epigenetic therapy. Armed with this information, in the independent phase, I will treat GBM cells with the DNA demethylating agent 5-Aza-CdR and measure the ability of demethylation to restore normal gene expression patterns and resolve aberrant chromatin structures. In addition to measuring DNA methylation, nucleosome occupancy and H2A.Z localization, I will assess tumorigenic potential by measuring neurosphere formation. During the mentored phase of the award, I will generate the genome-wide maps of DNA methylation, nucleosome occupancy and H2A.Z localization, which will characterize the epigenetic landscape of normal human neural progenitors and GBM cells. I will also learn new bioinformatics techniques necessary for analyzing genome wide epigenomic data and participate in career development opportunities that will help in obtaining and succeeding as an independent position at an academic research institution. RELEVANCE: GBM tumors are difficult to treat, and little is known about the epigenetic landscape of these cells. Understanding the epigenetic alterations in these cells and how they respond to DNA demethylation treatment will have important implications for future therapies. Here I will investigate several levels of epigenetic regulation and how they are altered in brain tumors.

描述（由申请人提供）：多形性胶质母细胞瘤（GBM）几乎普遍具有致命性，自首次诊断起的中位生存期为12-18个月，需要新的治疗方法。表观遗传学和遗传学在癌症发生的所有阶段都有合作，包括脑肿瘤。表观遗传机制围绕着核小体，核小体是一种由组蛋白和DNA组成的核心结构，DNA包裹在组蛋白核心周围。多种表观遗传机制共同作用以产生促进或抑制基因活化的染色质状态。这些机制包括DNA甲基化（在CpG位点），组蛋白变体和修饰以及核小体定位。染色质状态的全基因组研究集中在表观遗传调控的各个方面，因此，表观遗传调控机制的综合图谱尚未完成，表观遗传调控机制共同决定转录状态。使用我一直在开发的一种新技术（GNOME Me-seq），我将在正常人类神经祖细胞和GBM细胞的同一DNA链内生成DNA甲基化和核小体定位的全基因组图谱。这将识别异常沉默的基因，除了染色质重塑外，这些基因还需要DNA去甲基化才能重新激活。该数据将与H2 A变体H2A.Z的定位特征相结合。除了存在于重要的基因组调控区域，如增强子和绝缘子，H2A.Z定位于活性和稳定的基因启动子。结合DNA甲基化、核小体占有率和H2A.Z定位数据将鉴定哪些基因组基因座是活性的、稳定的和沉默的，从而提供详细描述GBM中存在的异常染色质结构的关键信息，这对表观遗传治疗具有重要意义。有了这些信息，在独立阶段，我将用DNA去甲基化剂5-Aza-CdR处理GBM细胞，并测量去甲基化恢复正常基因表达模式和解决异常染色质结构的能力。除了测量DNA甲基化、核小体占有率和H2A.Z定位外，我还将通过测量神经球形成来评估致瘤潜力。在该奖项的指导阶段，我将生成DNA甲基化，核小体占用和H2A.Z定位的全基因组图谱，这将表征正常人类神经祖细胞和GBM细胞的表观遗传景观。我还将学习分析全基因组表观基因组数据所需的新生物信息学技术，并参与职业发展机会，这将有助于在学术研究机构获得独立职位并取得成功。相关性：GBM肿瘤很难治疗，并且对这些细胞的表观遗传景观知之甚少。了解这些细胞中的表观遗传学改变以及它们如何对DNA去甲基化治疗作出反应将对未来的治疗具有重要意义。在这里，我将研究几个层次的表观遗传调控，以及它们如何在脑肿瘤中改变。