The role of PTEN in epigenetic and metabolic regulation of IDH-mutant gliomas

PTEN 在 IDH 突变胶质瘤表观遗传和代谢调控中的作用

• 批准号: 10750036
• 负责人: James Robert Haggerty-Skeans
• 金额: $ 4.04万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10750036
• 关键词: Address; Animal Model; Astrocytes; Astrocytoma; Biological; Biological Assay; Cell Line; Cell Proliferation; Cells; Central Nervous System Neoplasms; ChIP-seq; Characteristics; Citric Acid Cycle; Clinical Trials; CpG Islands; Critiques; DNA; DNA Methylation; DNA methylation profiling; Data; Decarboxylation; Dioxygenases; Disadvantaged; Electroporation; Enzyme Inhibition; Enzymes; Epigenetic Process; FRAP1 gene; Funding; Gene Expression; Genes; Genetic; Genomics; Glioma; Glucose; Glutamine; Goals; Grant; Histones; Human; Hypermethylation; In Vitro; Isocitrate Dehydrogenase; Isocitrates; Isotopes; Knowledge; Link; Loss of Heterozygosity; Malignant - descriptor; Malignant Neoplasms; Malignant neoplasm of brain; Maps; Mediating; Medical; Metabolic; Metabolic Pathway; Metabolism; Methylation; Modeling; Molecular; Mus; Mutate; Mutation; Newly Diagnosed; Outcome; PIK3CG gene; PTEN gene; Phenotype; Physicians; Prognosis; Proteins; Proto-Oncogene Proteins c-akt; Published Comment; Regulation; Research; Role; Scientist; Signal Transduction; Testing; Therapeutic; Training; Translating; Tumor Suppressor Proteins; Tumorigenicity; Work; alpha ketoglutarate; bisulfite; career; cell type; cellular engineering; clinical heterogeneity; curative treatments; demethylation; effective therapy; epigenome; experimental study; genome-wide; histone demethylase; histone methylation; in utero; in vivo; inhibitor; knock-down; mutant; nervous system disorder; new therapeutic target; next generation sequencing; novel; prognostic; programs; protein expression; targeted treatment; therapeutic candidate; therapeutic development; transcriptome sequencing; tumor; tumor growth

ABSTRACT Astrocytic tumors of the central nervous system (CNS) are intractable tumors and harbor dismal outcomes due to a lack of targeted treatment options. More than 70% of astrocytic tumors bear mutations in the TCA cycle- related gene, isocitrate dehydrogenase 1 (IDH1). Wildtype IDH1 catalyzes the oxidative decarboxylation of isocitrate to generate α-Ketoglutarate (αKG), while mutated IDH1 (IDH1m) metabolizes αKG into the oncometabolite D-2-hydroxyglutarate (D2HG). Several epigenetic dioxygenases including histone and DNA demethylases require αKG to demethylate histone residues and DNA CpG islands. D2HG competitively inhibits these enzymes due to its structural similarity to αKG. This results in an increase in histone and DNA methylation referred to as the glioma-CpG island methylation phenotype (G-CIMP). However, DNA methylation G-CIMP levels are not uniform in IDH1m astrocytomas. IDH1m astrocytomas with low versus high levels of G- CIMP bear a particularly grim prognosis. My preliminary data identifies PTEN loss of heterozygosity (LOH) as the top genetic alteration in G-CIMP low versus G-CIMP high tumors. Moreover, PTEN LOH independently related with a poor prognosis. However, it remains unknown how PTEN LOH drives tumorigenicity in IDH1m astrocytomas. Our premise is based on the observation that PTEN is a critical tumor suppressor. In other cancers, PTEN LOH activates PI3-kinase (PI3K)/AKT-mTOR signaling to drive tumor growth through various mechanisms including metabolic reprogramming. My preliminary data demonstrates increased cell proliferation in IDH1m astrocytic cell lines with partial PTEN knockdown (KD) accompanied by a reduction in D2HG levels. Based on my premise and preliminary data, I hypothesize that PTEN LOH activates PI3K/AKT-mTOR signaling to metabolically reprogram IDH1m astrocytomas to reduce D2HG levels and thereby mediate lowered DNA methylation and G-CIMP levels. Subsequently, targeting PI3K/AKT-mTOR signaling represents a promising candidate for therapeutic development. To test this hypothesis, I propose two specific aims. Aim 1 will map alterations in metabolic pathways that generate D2HG in human and murine-derived IDH1m astrocytomas with or without PTEN reduction using a novel in-utero electroporation (IUE) Pten +/- IDH1m model. In parallel, I will assess corresponding genome wide epigenetic alterations including DNA methylation using next generation sequencing-based epigenetic assays in relation to changes in gene expression. Aim 2 will determine if targeting PTEN LOH-driven PI3K/AKT-mTOR activation is therapeutic in vitro and proof-of-principle in animal models. Together, my work will address a critical gap in our knowledge by defining how PTEN LOH drives a subset of aggressive IDH1m astrocytomas via metabolic reprograming and lay the groundwork for developing targeted and effective therapies for malignant IDH1m astrocytomas.

抽象的 中枢神经系统（CNS）的星形细胞肿瘤是棘手的肿瘤，蒙受了惨淡的结果 缺乏针对性的治疗选择。在TCA循环中，超过70％的星形细胞肿瘤具有突变 相关基因，异氯酸盐脱氢酶1（IDH1）。野生型IDH1催化氧化脱羧 异位酸盐生成α-酮戊二酸（αkg），而突变的IDH1（IDH1M）将αkg代谢到该αkg中 oncometabolite d-2-羟基戊二酸（D2HG）。几种表观遗传二氧酶，包括组蛋白和DNA 脱甲基酶需要αkg才能将组蛋白残留和DNA CPG岛脱甲基化。 D2HG竞争性 由于其与αkg的结构相似性，抑制了这些酶。这导致组蛋白和DNA增加 甲基化称为神经胶质瘤-CPG岛甲基化表型（G-CIMP）。但是，DNA甲基化 IDH1M星形胶质细胞瘤中的G-CIMP水平并不均匀。 IDH1M的星形胶质细胞瘤，低水平与高水平的G- CIMP熊特别严峻。我的初步数据将PTEN的杂合性丧失（LOH）确定为 G-CIMP低肿瘤与G-CIMP高肿瘤的最高遗传改变。而且，Pten Loh独立 与预后不良有关。但是，尚不清楚Pten Loh如何在IDH1M中驱动肿瘤性 星形胶质细胞瘤。我们的前提是基于观察到PTEN是一个关键的肿瘤抑制剂。在其他 癌症，PTEN LOH激活PI3-激酶（PI3K）/Akt-MTOR信号传导以通过各种 包括代谢重编程的机制。我的初步数据表明细胞增殖增加 在IDH1M的星形细胞细胞系中，通过降低D2HG水平来完成部分PTEN敲低（KD）。 根据我的前提和初步数据，我假设PTEN LOH激活PI3K/AKT-MTOR信号传导 代谢重新编程IDH1M星形胶质细胞瘤以降低D2HG水平，从而介导降低的DNA 甲基化和G-CIMP水平。随后，针对PI3K/AKT-MTOR信号代表一个承诺 热发育候选人。为了检验这一假设，我提出了两个具体目标。 AIM 1将映射 在人和鼠类衍生的IDH1M星形胶质细胞中产生D2HG的代谢途径的改变 或不使用新型utero电穿孔（IUE）PTEN +/- IDH1M模型而无需降低PTEN。同时，我会 评估相应的基因组广泛的表观遗传学改变，包括使用下一代的DNA甲基化 基于测序的表观遗传测定与基因表达变化有关。 AIM 2将确定是否 靶向PTEN LOH驱动的PI3K/Akt-MTOR激活是在动物的体外治疗和原则的治疗证明 型号。我的工作在一起将通过定义Pten Loh如何驱动A来解决我们知识的关键差距 积极的IDH1M星形胶质细胞瘤的子集通过代谢重编程和开发奠定基础 针对恶性IDH1M星形胶质细胞瘤的有效疗法。