Novel Approaches to Modeling and Treating IDH1 Mutant Glioma

IDH1 突变神经胶质瘤建模和治疗的新方法

基本信息

批准号：
10247533
负责人：
Samuel Kent McBrayer
金额：
$ 13.94万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
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：
2019-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10247533
关键词：
ATRX gene Address Adult Anabolism Anaplastic astrocytoma Area Aspartate Astrocytoma Brain Brain Neoplasms Branched-Chain Amino Acids CRISPR/Cas technology Cells Chemicals Clinical Clinical Data Clinical Research DHODH gene Data Development Dihydroorotate dehydrogenase Dioxygenases Disease Disease model Engineering Enzymes Future Genes Genetic Genetic Engineering Genetically Engineered Mouse Glioblastoma Glioma Gliomagenesis Histones Hot Spot Human Hypersensitivity Impairment In Vitro Incidence Isocitrate Dehydrogenase Knowledge Link Lysine Malignant neoplasm of brain Mediating Metabolic Modeling Molecular Mus Mutate Mutation Neuroglia Neurons Nitrogen Nucleotides Oncogenes Pathogenesis Pathway interactions Patients Penetrance Pharmacology Procollagen-Proline Dioxygenase Production Pyrimidine Pyrimidine Nucleotides Radiation therapy Recurrence Specificity Testing Therapeutic Tissues Translating Tumor Biology Xenograft Model Xenograft procedure alpha ketoglutarate base branched-chain-amino-acid transaminase cell transformation cytotoxicity test effective therapy efficacy testing enzyme biosynthesis glioma cell line in vivo in vivo Model inhibitor/antagonist insight leukemia mouse model mutant mutant mouse model novel novel strategies novel therapeutic intervention novel therapeutics nucleotide metabolism pre-clinical preclinical study predictive marker research clinical testing response response biomarker therapeutically effective treatment strategy tumor

项目摘要

PROJECT SUMMARY Hot-spot mutations in the isocitrate dehydrogenase 1 (IDH1) gene are highly recurrent in lower grade gliomas (LGGs) and secondary glioblastomas (GBMs) and encode the mutant IDH1-R132H enzyme. This enzyme displays neomorphic activity, converting 2-oxoglutarate (2OG) to the oncometabolite (R)-2-hydroxyglutarate ((R)-2HG). (R)-2HG accumulates to millimolar levels in IDH1 mutant gliomas and promotes gliomagenesis by competitively modulating 2OG-dependent enzymes that regulate glial cell transformation. Although these discoveries have profoundly reshaped our understanding of the molecular pathogenesis of these diseases, these insights have not yet translated to the development of new, effective therapeutic strategies for glioma patients. Direct inhibitors of the mutant IDH enzyme have shown poor activity in early preclinical and clinical studies of IDH mutant glioma relative to the robust efficacy they display against IDH mutant leukemias. These findings highlight the clinical need for alternative therapeutic strategies to treat IDH1 mutant gliomas. I hypothesize that novel treatment strategies can be developed by exploiting synthetic lethality with the IDH1- R132H oncogene. I performed a chemical synthetic lethality screen using isogenic IDH1 mutant and wild-type glioma cell lines and found that multiple pyrimidine synthesis inhibitors preferentially killed IDH1 mutant cells. My preliminary data shows that (R)-2HG-mediated inhibition of the 2OG-dependent branched chain amino acid transaminases BCAT1 and BCAT2 impairs nitrogen incorporation into the pyrimidine biosynthesis pathway. Therefore, in Aim 1 I will test whether reduced BCAT activity represents the molecular mechanism underlying mutant IDH1-induced pyrimidine synthesis inhibitor hypersensitivity. I will go on to assess whether the IDH1- R132H mutation is a predictive biomarker for response to pyrimidine synthesis inhibitors by testing the cytotoxicity of these agents against a panel of IDH1 mutant and wild-type glioma neurosphere lines. Finally, I will test a novel brain-penetrant inhibitor of the pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase (DHODH) alone and in combination with radiotherapy in xenograft models of IDH1 mutant glioma. Another major impediment to the development of new, effective therapeutic strategies for IDH1 mutant glioma is a paucity of genetically-engineered mouse (GEM) models of this disease that can be used to evaluate such strategies. In Aim 2 I propose to establish the first Crispr/Cas9-based GEM models of glioma driven by mutant IDH1. I have successfully produced mutant Idh1-driven Grade III anaplastic astrocytomas in mice and I will optimize my approach to increase astrocytoma penetrance in this GEM model. I will also modify my strategy to generate isogenic GEM models of IDH1 mutant and wild-type GBM that can be used for future in vivo studies of synthetic lethality with the Idh1-R132H oncogene. If successful, these projects will establish rationale for clinical testing of pyrimidine synthesis inhibitors for IDH1 mutant glioma therapy and generate GEM models of this disease to support future testing of newly devised treatment strategies.

项目概要异柠檬酸脱氢酶 1 (IDH1) 基因的热点突变在低级别胶质瘤中高度复发 (LGG) 和继发性胶质母细胞瘤 (GBM) 并编码突变 IDH1-R132H 酶。这种酶显示新形态活性，将 2-酮戊二酸 (2OG) 转化为致癌代谢物 (R)-2-羟基戊二酸 ((R)-2HG)。 (R)-2HG 在 IDH1 突变神经胶质瘤中积累至毫摩尔水平，并通过以下方式促进神经胶质瘤发生竞争性调节 2OG 依赖性酶，调节神经胶质细胞转化。虽然这些这些发现深刻地重塑了我们对这些疾病的分子发病机制的理解，这些见解尚未转化为开发新的、有效的神经胶质瘤治疗策略患者。突变 IDH 酶的直接抑制剂在早期临床前和临床中表现出较差的活性 IDH 突变神经胶质瘤的研究相对于它们对 IDH 突变白血病的强大功效。这些研究结果强调临床需要替代治疗策略来治疗 IDH1 突变神经胶质瘤。我假设可以通过利用 IDH1- 的合成致死作用来开发新的治疗策略 R132H 癌基因。我使用同基因 IDH1 突变体和野生型进行了化学合成致死率筛选神经胶质瘤细胞系，发现多种嘧啶合成抑制剂优先杀死 IDH1 突变细胞。我的初步数据表明 (R)-2HG 介导的 2OG 依赖性支链氨基酸抑制转氨酶 BCAT1 和 BCAT2 会损害氮并入嘧啶生物合成途径。因此，在目标 1 中，我将测试 BCAT 活性降低是否代表了潜在的分子机制突变 IDH1 诱导的嘧啶合成抑制剂超敏反应。我将继续评估 IDH1- R132H 突变是通过测试对嘧啶合成抑制剂反应的预测生物标志物这些药物对 IDH1 突变体和野生型神经胶质瘤神经球系的细胞毒性。最后，我将测试一种新型的嘧啶生物合成酶二氢乳清酸脱氢酶的脑渗透抑制剂 (DHODH) 在 IDH1 突变神经胶质瘤的异种移植模型中单独使用或与放疗联合使用。其他开发针对 IDH1 突变神经胶质瘤的新的、有效的治疗策略的主要障碍是缺乏可用于评估此类疾病的基因工程小鼠 (GEM) 模型策略。在目标 2 中，我建议建立第一个基于 Crispr/Cas9 的突变体驱动的神经胶质瘤 GEM 模型 IDH1。我已经成功地在小鼠体内产生了突变型 Idh1 驱动的 III 级间变性星形细胞瘤，我将优化我在这个 GEM 模型中增加星形细胞瘤外显率的方法。我也会修改我的策略生成 IDH1 突变体和野生型 GBM 的同基因 GEM 模型，可用于未来的体内研究 Idh1-R132H 癌基因的合成致死率。如果成功，这些项目将为嘧啶合成抑制剂用于 IDH1 突变神经胶质瘤治疗的临床测试并生成 GEM 模型这种疾病以支持未来新设计的治疗策略的测试。