Mechanisms and therapeutic implications of temozolomide resistance in glioblastoma

胶质母细胞瘤替莫唑胺耐药的机制和治疗意义

• 批准号: 10463343
• 负责人: Matthew McCord
• 金额: $ 7.17万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10463343
• 关键词: Address; Adult; Alkylating Agents; Apoptosis; Bioinformatics; Biological Assay; Brain Neoplasms; Cell Line; Cells; Clinical; Clinical Trials; Clustered Regularly Interspaced Short Palindromic Repeats; DNA; DNA Alkylation; Data; Defect; Diagnostic; Diffuse; Dose; Educational workshop; Effector Cell; Excision; Fellowship; Funding; Genomics; Glioblastoma; Glioma; Goals; Hereditary Nonpolyposis Colorectal Neoplasms; Heterogeneity; Immune; Immune checkpoint inhibitor; Immune response; Immune system; Immunocompetent; Immunofluorescence Immunologic; Immunology; Immunotherapy; Impairment; In Vitro; Infiltration; Knock-out; Lead; Link; MSH2 gene; MSH6 gene; Malignant Neoplasms; Mentors; Mismatch Repair; Mismatch Repair Deficiency; Mitosis; Modeling; Mus; Mutation; Patients; Pattern; Phenotype; Physicians; Population; Primary Brain Neoplasms; Process; Prognosis; Publishing; Radiation; Recurrence; Research; Research Training; Resistance; Resistance development; Role; Scientist; T-Lymphocyte; Testing; Therapeutic; Time; Tissue Sample; Tissues; Training; Universities; Variant; base; career; cell type; checkpoint inhibition; chemotherapy; design; experimental study; genome sequencing; human tissue; immunogenic; immunosuppressed; improved; in vivo; knockout gene; mutant; neoantigens; neuropathology; patient derived xenograft model; repair enzyme; repaired; response; spatial relationship; standard of care; subclonal heterogeneity; success; temozolomide; treatment effect; tumor; tumor heterogeneity; whole genome

PROJECT SUMMARY This fellowship proposal describes a three-year research and training plan designed to prepare Dr. Matthew McCord, a clinical fellow in neuropathology at Northwestern University, for a career as a physician-scientist. Dr. McCord's long term goal is to become an expert diagnostic neuropathologist and independently-funded brain tumor research scientist. The research plan is focused on better understanding temozolomide (TMZ) resistance and TMZ-driven hypermutation in glioblastoma (GBM). Chemotherapy with temozolomide (TMZ) is standard-of- care for GBM, and temporarily extends survival. However, tumors universally recur and develop TMZ resistance, and are almost uniformly fatal. Defects in DNA mismatch repair (MMR) enzymes, most commonly Msh6, have been linked to TMZ resistance in recurrent GBM. A subset of post-TMZ recurrent GBMs develop extremely high tumor mutation burden (TMB), also known as a “hypermutated” phenotype, which has also been linked to MMR defects, like Msh6. However, a clear causal relationship between impaired Msh6 and hypermutation in response to TMZ has not yet been experimentally proven. Certain types of hypermutated cancer arising elsewhere in the body have proven responsive to immune checkpoint inhibition (ICI), but in clinical trials of hypermutated GBMs, ICI responsiveness has been uneven, for reasons that are not entirely clear. Previously published data, from Dr. McCord and others, suggest that Msh6 impairment and hypermutation may be heterogeneous, occurring only in subclones of GBM that, via global genomic assays, appear to be hypermutated. This could help explain the inconsistent effects of ICI in trials thus far. The central hypothesis of the proposal is that MMR defects facilitate hypermutation in the presence of temozolomide and ICI responsiveness, but that sub-clonal variation in these defects contributes to variable ICI efficacy. Specific Aims to test this hypothesis are as follows: (1) prove a causative role for MSH6 in TMZ-driven hypermutation and TMZ resistance, through MSH6 gene knockout experiments in glioma cells; (2) demonstrate the intratumoral heterogeneity of Msh6 impairment and hypermutation, via single cell whole genome sequencing, in post-TMZ patient-derived gliomas and TMZ-resistant patient-derived xenografts (PDX); (3) evaluate the in vivo sensitivity of hypermutated versus non-hypermutated tumor subclones to TMZ and ICI by creating orthotopic intracranial GBMs with varying proportions of each cell type, then treating with both TMZ and ICI. The training plan for Dr. McCord is tailored to the proposed research, with focused mentoring, workshops, and coursework on bioinformatics, immunology, and glioma models, as well as addressing specific issues relevant for nascent physician-scientists. This fellowship will provide support for Dr. McCord at a critical juncture in his career, will enable him to eventually compete for both K- and R-level funding, and will also advance understanding of why GBMs develop resistance to both TMZ and ICI therapy.

项目摘要 该奖学金提案描述了一项为期三年的研究和培训计划，旨在为马修博士做准备。 麦考德（McCord）是西北大学神经病理学临床研究员，从事身体科学家的职业。博士 麦考德的长期目标是成为一名专家诊断神经病理学家和独立资助的大脑 肿瘤研究科学家。该研究计划的重点是更好地理解替莫唑胺（TMZ）抗性 和TMZ驱动的胶质母细胞瘤（GBM）中的超突变。替莫唑胺（TMZ）化学疗法是 - 照顾GBM，并暂时扩大生存。然而，肿瘤普遍复发并发展出TMZ抗性， 并且几乎是统一致命的。 DNA不匹配修复（MMR）酶（最常见的MSH6）的缺陷具有 与复发性GBM中的TMZ抗性有关。 TMZ后复发性GBM的子集表现得极高 肿瘤突变Burnen（TMB），也称为“超重”表型，它也与MMR有关 缺陷，例如MSH6。但是，MSH6和反应中的超名之间存在明显的因果关系 对于TMZ，尚未经过实验证明。某些类型的高水癌症在其他地方出现 身体对免疫检查点抑制（ICI）有证明有反应，但是在超沉积的GBM的临床试验中， 出于不完全清楚的原因，ICI的响应能力不平衡。先前发布的数据，博士 麦考德和其他人表明，MSH6损伤和过度突击可能是异质的，仅发生在 通过全球基因组测定，GBM的亚克隆似乎已经过度充实。这可以帮助解释 到目前为止，ICI在试验中的影响不一致。该提案的中心假设是制备的MMR缺陷 在替莫唑胺和ICI响应性存在下的超变量，但是这些亚克隆变化 缺陷有助于可变的ICI效率。检验该假设的具体目的如下：（1）证明A MSH6在TMZ驱动的超名和TMZ抗性中的病因作用，通过MSH6基因敲除 神经胶质瘤细胞的实验； （2）证明MSH6损伤的肿瘤内异质性 TMZ后患者衍生的神经胶质瘤和抗TMZ的抗性，通过单细胞全基因组测序的超代性通过全基因组测序 患者衍生的Xenographictic（PDX）； （3）评估超浮装与非杂种的体内灵敏度 肿瘤亚克隆通过创建与每个细胞比例变化的原位颅内GBM通过创建原位的TMZ和ICI 类型，然后使用TMZ和ICI处理。麦考德博士的培训计划是针对拟议的研究量身定制的 还通过有关生物信息学，免疫学和神经胶质瘤模型的重点心理，讲习班和课程工作 解决与新生物理科学家相关的特定问题。该奖学金将为 麦考德博士在职业生涯中的一个关键时刻将使他最终竞争K-和R级别 资金，还将进一步了解为什么GBM对TMZ和ICI疗法都具有抵抗力。