Tet2 regulation and function in glioma cell phenotype reprogramming

Tet2在神经胶质瘤细胞表型重编程中的调节和功能

基本信息

批准号：
10417120
负责人：
John J Laterra
金额：
$ 35.35万
依托单位：
HUGO W. MOSER RES INST KENNEDY KRIEGER
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-01 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10417120
关键词：
Animals CRISPR/Cas technology Cell model Cells Chromatin Structure Clinical Clinical Data DNA DNA Methylation Data Dissection Down-Regulation Epigenetic Process Event Gene Expression Gene Silencing Generations Genes Genetic Transcription Glioblastoma Glioma Goals Growth Heterogeneity Human Knock-out Knowledge Malignant Neoplasms Malignant neoplasm of brain Methylation MicroRNAs Molecular Oncogenic Patient-Focused Outcomes Patients Pattern Phenotype Point Mutation Prognosis Proteins Publishing Reaction Recurrence Regulation Reporting Research Resistance Role Study models Testing Tetanus Helper Peptide Therapeutic Untranslated RNA Xenograft procedure antitumor effect cancer stem cell clinically translatable cytotoxic effective therapy experimental study improved in vivo knock-down loss of function methylome nanoparticle neoplastic cell novel novel strategies pre-clinical programs protein protein interaction self renewing cell stem stem cells stem-like cell stemness therapeutic target therapy outcome transcription factor transcriptional reprogramming transcriptome tumor tumor growth

项目摘要

Glioblastoma (GBM) represents the most aggressive and lethal form of primary brain cancer. We now know that GBM contains small subsets of cells that display tumor-propagating stem-like phenotypes (GBM stem cells, GSCs) that act as critical determinants of GBM resistance to current treatments and tumor recurrence. Understanding and ultimately targeting the epigenetic mechanisms that induce and maintain these tumor- propagating cell subsets is critical to improving GBM therapy and patient outcomes. Altered patterns of DNA methylation are widely reported in human GBM. However, substantial knowledge gaps remain in our understanding of the molecular mechanisms responsible for this epigenetic dysregulation, its downstream consequences and role in the tumor propagating GSC phenotype. This proposal builds on our published and preliminary findings that oncogenic reprogramming transcription factors induce tumor propagating GBM stem cells by regulating miRNA networks that target determinants of DNA methylation. Our new preliminary data implicate a previously unrecognized Sox2:miR-10b-5p:Tet2 axis by which Sox2 induces onco-miR10b-5p that represses the Tet2 demethylase in GBM cells. This axis decreases the conversion of 5-methylcytosine to 5- hydroxymethylcytosine (5hmC), the reaction catalyzed by TET (Ten Eleven Translocation) proteins and a key intermediate step in DNA de-methylation. The potential significance of this axis on oncogenic transcriptome generation is supported by clinical data showing that miR-10b-5p expression is substantially elevated in GBM, that low Tet2 and low 5-hmc expression correlate with poor prognosis in GBM patients, and that Tet2 knock- down accelerates the invasive growth of GBM xenografts. This proposal will test the hypothesis that Sox2 drives tumor-propagating GSCs by activating onco-miR-10b-5p that represses Tet2 resulting in an oncogenic DNA methylome and transcriptome. These goals will be achieved through the following specific aims: (i) Determine how the Sox2:miR-10b:Tet2 axis modifies the DNA methylation landscape of GSCs; (ii) Determine how enzymatic and non-enzymatic functions of Tet2 regulate GSCs; (iii) Determine the potential to treat GBM in vivo by inhibiting Tet2 down-regulation by miR-10b-5p. Successful execution of the proposed research plan will fill critical gaps in our understanding of epigenetic molecular events by which reprogramming transcription factors induce tumor propagating cells in GBM through transcriptional silencing, and establish the potential to treat GBM by targeting this novel axis that alters the tumor transcriptome via Tet2 inhibition.

胶质母细胞瘤（GBM）代表原发性脑癌中最具侵袭性和致命性的形式。我们现在知道 GBM 包含小部分细胞，这些细胞表现出肿瘤增殖干细胞样表型（GBM 干细胞）细胞（GSC）是 GBM 对当前治疗耐药和肿瘤复发的关键决定因素。了解并最终针对诱导和维持这些肿瘤的表观遗传机制增殖细胞亚群对于改善 GBM 治疗和患者预后至关重要。 DNA 模式改变甲基化在人类 GBM 中被广泛报道。然而，我们仍然存在巨大的知识差距了解导致这种表观遗传失调及其下游的分子机制后果和在肿瘤增殖 GSC 表型中的作用。该提案建立在我们已发布和初步发现致癌重编程转录因子诱导肿瘤增殖 GBM 干细胞通过调节针对 DNA 甲基化决定因素的 miRNA 网络来控制细胞。我们的新初步数据暗示以前未被识别的 Sox2:miR-10b-5p:Tet2 轴，Sox2 通过该轴诱导 onco-miR10b-5p 抑制 GBM 细胞中的 Tet2 去甲基酶。该轴减少 5-甲基胞嘧啶向 5- 羟甲基胞嘧啶 (5hmC)，TET（十一个十一易位）蛋白催化的反应和一个关键 DNA去甲基化的中间步骤。该轴对致癌转录组的潜在意义临床数据支持这一生成，表明 miR-10b-5p 表达在 GBM 中显着升高，低 Tet2 和低 5-hmc 表达与 GBM 患者的不良预后相关，并且 Tet2 敲除下降加速了 GBM 异种移植物的侵袭性生长。该提案将检验 Sox2 的假设通过激活抑制 Tet2 的 onco-miR-10b-5p 来驱动肿瘤增殖 GSC，从而产生致癌性 DNA 甲基化组和转录组。这些目标将通过以下具体目标来实现：(i) 确定 Sox2:miR-10b:Tet2 轴如何改变 GSC 的 DNA 甲基化景观； (二) 确定 Tet2 的酶促和非酶促功能如何调节 GSC； (iii) 确定治疗 GBM 的潜力在体内通过 miR-10b-5p 抑制 Tet2 下调。所提出的研究计划的成功执行将填补我们对表观遗传分子事件理解的关键空白，通过重编程转录因子通过转录沉默诱导 GBM 中的肿瘤增殖细胞，并建立了潜在的通过靶向这一通过 Tet2 抑制改变肿瘤转录组的新轴来治疗 GBM。