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）：多形胶质母细胞瘤（GBM）几乎是普遍致命的，自初次诊断之时起12-18个月的存活率和新的治疗方法。表观遗传学和遗传学在癌变的各个阶段，包括脑肿瘤。表观遗传机制围绕核小体，该结构由组蛋白蛋白和DNA的核心组成，该结构包裹在组蛋白核心周围。多种表观遗传机制共同起作用，以产生促进或抑制基因激活的染色质。这些机制包括DNA甲基化（在CPG位点），组蛋白变异和修饰以及核小体定位。染色质状态的基因组广泛研究集中在表观遗传调节的各个方面，因此，尚未完成表观遗传调节机制的综合图表，这些综合确定了转录状态。使用我一直在开发的新技术（GNOME-SEQ），我将在正常人神经祖细胞和GBM细胞的相同DNA链中生成基因组宽图和核小体定位的基因组宽图。这将确定异常沉默的基因，除染色质重塑以进行重新激活外，还需要DNA脱甲基化。该数据将与H2A变体H2A.Z的本地化概况相结合。除了在重要的基因组调节区域（如增强子和绝缘子）等重要性区域外，H2A.Z还位于活跃和固定的基因启动子上。将DNA甲基化，核小体占用率和H2A.Z定位数据结合在一起，将确定哪些基因组基因座是活跃，固定和沉默的，从而提供了关键的信息，详细介绍了GBM中存在的异常染色质结构，这对表观遗传治疗具有重要意义。在独立阶段，我将用这些信息使用DNA脱甲基化剂5-Aza-CDR处理GBM细胞，并测量脱甲基恢复正常基因表达模式并解决异常染色质结构的能力。除了测量DNA甲基化，核小体占用率和H2A.Z的定位外，我还将通过测量神经圈形成评估致瘤潜力。在奖励的指导阶段，我将生成DNA甲基化，核小体占用和H2A.Z定位的全基因组图，这将表征正常人类神经祖细胞和GBM细胞的表观遗传景观。我还将学习分析基因组广泛的表观基因组数据所必需的新生物信息学技术，并参与职业发展机会，这将有助于获得和成功成为学术研究机构的独立职位。相关性：GBM肿瘤难以治疗，对这些细胞的表观遗传景观知之甚少。了解这些细胞的表观遗传改变以及它们如何对DNA脱甲基化治疗的反应将对未来的疗法具有重要意义。在这里，我将研究几个水平的表观遗传调节以及它们如何改变脑肿瘤。