TOP2A effects on transcription in gliomas: implications for personalized therapy

TOP2A 对神经胶质瘤转录的影响：对个性化治疗的影响

• 批准号: 9548054
• 负责人: Adam M Sonabend
• 金额: $ 39.5万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-22 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9548054
• 关键词: Address; Affect; Binding; Biological Assay; Brain; Brain Neoplasms; Cell Cycle; Cell Cycle Progression; Cell Line; Cell Survival; ChIP-seq; Characteristics; Chromatin; Clinical Trials; DNA; DNA Binding; DNA Damage; DNA Double Strand Break; DNA Repair; DNA topoisomerase II alpha; DNA-Directed RNA Polymerase; Diagnosis; Drug Delivery Systems; Drug Targeting; Enzymes; Etoposide; Excision; Future; Gene Expression; Gene Expression Profile; Genes; Genetic Transcription; Genomics; Glioblastoma; Glioma; Goals; Histones; Hour; Human; Lysine; Malignant - descriptor; Malignant neoplasm of brain; Methylation; Molecular; Mus; Mutation; Neuronavigation; Operative Surgical Procedures; Patient Selection; Patients; Pattern; Pharmaceutical Preparations; Phenotype; Play; Primary Brain Neoplasms; Process; Proteins; Radiation; Recurrence; Resectable; Role; Sampling; Specimen; Stem cells; Techniques; Testing; Time; Transcription Alteration; Transcriptional Regulation; Transgenic Mice; base; cancer genome; cell killing; chemotherapy; cytotoxic; design; epigenetic regulation; experimental study; genetic selection; glioma cell line; histone methylation; in vivo; insight; mouse model; neoplastic cell; patient subsets; personalized medicine; pluripotency; public health relevance; response; therapeutic target; therapy design; transcription factor; tumor; tumor progression

 DESCRIPTION (provided by applicant): Glioblastomas (GBMs), the most common and malignant of all primary brain tumors, infiltrate the brain and are lethal. GBM can be diagnosed de novo, or result from progression of lower-grade gliomas. All GBMs undergo the same non-curative treatment, including surgery, chemotherapy and radiation. Given that molecular characteristics are highly variable across GBMs, these tumors have been classified into subtypes based on gene expression patterns. These expression patterns and their underlying mechanisms might provide a unique tumoral vulnerability, a possibility not yet explored. Many transcription factors that control gene expression on proneural GBM subtype during glioma progression appear to be modulated by Topoisomerase IIA (TOP2A), an enzyme expressed by these tumors since early stages. TOP2A is involved in cell cycle progression, DNA repair and transcription. TOP2A de-coils DNA and enhances chromatin accessibility by creating transient double strand-DNA breaks (DSB). In stem cells, TOP2A regulates transcription at loci with histone 3 lysine 4 methylation (H3K4me2), but its role in GBM is unknown. Etoposide, a TOP2A-targeting drug that induces cytotoxic DSB is efficacious for a subset of GBM patients. Using mouse models, I showed that delivery of etoposide directly into these brain tumors led to higher efficacy than the concentration achievable by systemic delivery. However, differences in etoposide sensitivity across GBMs remain unexplained. I propose to study TOP2A's role on transcriptional regulation on GBM, and how it relates to etoposide sensitivity. To do this, using cell lines I will investigate whether histone methylation mark H3K4me2 influences TOP2A binding to the tumor genome, and how this affects gene expression. Using human GBM specimens, I will compare samples with elevated TOP2A to those lacking this enzyme. I will also explore TOP2A activity across different tumor grades. Using neuro-navigation guidance, I will investigate the differences in TOP2A at the resectable portion of GBM, and at the tumor margins to explore whether tumor cells infiltrating the brain can be targeted with etoposide. TOP2A DNA binding and DSB are common to transcriptional regulation by this enzyme and its targeting with etoposide, potentially rendering tumors that are transcriptionally regulated by TOP2A susceptible to this drug. I will explore this relationship on GBM cell lines with variable etoposide sensitivity. To explore the role of TOP2A on progression, I will study TOP2A transcriptional regulation at different times in transgenic mouse gliomas. To explore the transcriptional alterations caused by etoposide in gliomas, I will study tumors following 12 hours of etoposide treatment, and at recurrence. In summary, I propose to characterize transcriptional regulation by TOP2A in GBM and its role on progression. I will identify the molecular criteria for personalizing intratumoral etoposide therapy and understand how disruption of transcriptional regulation with etoposide influences recurrence. TOP2A as a target for infiltrating tumor also will be explored. The overarching goal is to design a personalized intratumoral etoposide trial for GBMs.

 描述（由申请人提供）：胶质母细胞瘤（GBM）是所有原发性脑肿瘤中最常见和最恶性的，可浸润大脑并致命。 GBM 可以从头诊断，也可以由低级别神经胶质瘤的进展引起。所有 GBM 均接受相同的非治愈性治疗，包括手术、化疗和放疗。鉴于 GBM 之间的分子特征差异很大，这些肿瘤已根据基因表达模式分为亚型。这些表达模式及其潜在机制可能提供独特的肿瘤脆弱性，但这种可能性尚未探索。在神经胶质瘤进展过程中，许多控制原神经 GBM 亚型基因表达的转录因子似乎受到拓扑异构酶 IIA (TOP2A) 的调节，拓扑异构酶 IIA (TOP2A) 是这些肿瘤从早期就表达的一种酶。 TOP2A 参与细胞周期进程、DNA 修复和转录。 TOP2A 通过产生瞬时双链 DNA 断裂 (DSB) 来解卷 DNA 并增强染色质可及性。在干细胞中，TOP2A 调节组蛋白 3 赖氨酸 4 甲基化 (H3K4me2) 位点的转录，但其在 GBM 中的作用尚不清楚。依托泊苷是一种诱导细胞毒性 DSB 的 TOP2A 靶向药物，对部分 GBM 患者有效。通过使用小鼠模型，我发现将依托泊苷直接递送至这些脑肿瘤中比全身递送可达到的浓度具有更高的疗效。然而，GBM 之间依托泊苷敏感性的差异仍无法解释。我建议研究 TOP2A 在 GBM 转录调控中的作用，以及它与依托泊苷敏感性的关系。为此，我将使用细胞系研究组蛋白甲基化标记 H3K4me2 是否影响 TOP2A 与肿瘤基因组的结合，以及这如何影响基因表达。我将使用人类 GBM 样本，将 TOP2A 升高的样本与缺乏这种酶的样本进行比较。我还将探索不同肿瘤级别的 TOP2A 活性。利用神经导航引导，我将研究 GBM 可切除部分和肿瘤边缘 TOP2A 的差异，以探讨依托泊苷是否可以靶向浸润大脑的肿瘤细胞。 TOP2A DNA 结合和 DSB 是该酶的转录调节及其以依托泊苷为靶点的常见机制，可能使受 TOP2A 转录调节的肿瘤对该药物敏感。我将探讨具有不同依托泊苷敏感性的 GBM 细胞系的这种关系。为了探索 TOP2A 在进展中的作用，我将研究转基因小鼠神经胶质瘤中不同时间的 TOP2A 转录调控。为了探索依托泊苷在神经胶质瘤中引起的转录改变，我将研究依托泊苷治疗 12 小时后以及复发时的肿瘤。总之，我建议描述 GBM 中 TOP2A 的转录调控及其在进展中的作用。我将确定个性化肿瘤内依托泊苷治疗的分子标准，并了解依托泊苷破坏转录调节如何影响复发。 TOP2A作为浸润肿瘤的靶点也将 被探索。总体目标是为 GBM 设计个性化瘤内依托泊苷试验。