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

基本信息

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
项目类别：
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

项目摘要

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) 的星形细胞肿瘤是难治性肿瘤，由于其预后较差超过 70% 的星形细胞肿瘤存在 TCA 周期突变。相关基因，异柠檬酸脱氢酶 1 (IDH1) 野生型 IDH1 催化氧化脱羧。异柠檬酸生成 α-酮戊二酸 (αKG)，而突变的 IDH1 (IDH1m) 将 αKG 代谢为致癌代谢物 D-2-羟基戊二酸 (D2HG)。多种表观遗传双加氧酶，包括组蛋白和 DNA。去甲基化酶需要 αKG 竞争性地使组蛋白残基和 DNA D2HG 岛去甲基化。由于其结构与 αKG 相似，因此会抑制这些酶，从而导致组蛋白和 DNA 增加。神经胶质瘤的甲基化称为CpG岛甲基化表型（G-CIMP），但DNA甲基化。 IDH1m 星形细胞瘤中 G-CIMP 水平不均匀，G-水平较低与较高。 CIMP 的预后尤其严峻。我的初步数据将 PTEN 杂合性丢失 (LOH) 确定为低 G-CIMP 肿瘤与高 G-CIMP 肿瘤中最主要的基因改变是 PTEN LOH 独立的。然而，PTEN LOH 如何驱动 IDH1m 的致瘤性仍不清楚。我们的前提是基于 PTEN 在其他肿瘤中是一种重要的肿瘤抑制因子的观察。在癌症中，PTEN LOH 激活 PI3 激酶 (PI3K)/AKT-mTOR 信号传导，通过多种途径驱动肿瘤生长我的初步数据表明细胞增殖增加。在具有部分 PTEN 敲低 (KD) 并伴随 D2HG 水平降低的 IDH1m 星形胶质细胞系中。根据我的前提和初步数据，我敢说 PTEN LOH 激活 PI3K/AKT-mTOR 信号传导对 IDH1m 星形细胞瘤进行代谢重编程以降低 D2HG 水平，从而介导 DNA 降低随后，针对 PI3K/AKT-mTOR 信号传导代表了一种有前途的方法。为了检验这一假设，我提出了两个具体目标。在人和鼠源性 IDH1m 星形细胞瘤中产生 D2HG 的代谢途径的改变或者不使用新型宫内电穿孔 (IUE) Pten +/- IDH1m 模型减少 PTEN。使用下一代评估相应的全基因组表观遗传改变，包括 DNA 甲基化目标 2 将确定与基因表达变化相关的基于测序的表观遗传分析。靶向 PTEN LOH 驱动的 PI3K/AKT-mTOR 激活具有体外治疗作用和动物原理验证我的工作将通过定义 PTEN LOH 如何驱动模型来弥补我们知识中的一个关键差距。通过代谢重编程治疗侵袭性 IDH1m 星形细胞瘤的子集，并为开发奠定基础恶性 IDH1m 星形细胞瘤的靶向有效治疗。