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

基本信息

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
项目类别：
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

项目摘要

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（由适用提供）：胶质母细胞瘤（GBMS），是所有原发性脑肿瘤中最常见和最恶性的，渗入大脑，致死。可以从头开始诊断GBM，也可以是由于下级神经胶质瘤的进展而引起的。所有GBM都接受了相同的非耐药治疗，包括手术，化学疗法和放射线。鉴于分子特征在整个GBM中都高度变化，因此这些肿瘤已根据基因表达模式分类为亚型。这些表达模式及其基本机制可能会提供独特的肿瘤脆弱性，尚未探索。在神经胶质瘤进展过程中控制基因表达的许多转录因子似乎是由拓扑异构酶IIA（TOP2A）调节的，这是这些肿瘤从早期开始就这些肿瘤表达的酶。 TOP2A参与细胞周期进程，DNA修复和转录。 Top2a De-coils DNA并通过创建瞬态双链DNA断裂（DSB）来增强染色质的可及性。在干细胞中，TOP2A用组蛋白3赖氨酸4甲基化（H3K4ME2）调节基因座的转录，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，对于GBM患者的子集有效。使用小鼠模型，我表明，依托泊苷直接递送到这些脑肿瘤中的效率高于全身递送所达到的浓度。然而，跨GBM的依托泊苷敏感性差异仍然未知。我建议研究TOP2A在GBM上转录调控中的作用，以及它与依托泊苷敏感性的关系。为此，使用细胞系我将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。使用人类GBM标本，我将比较具有TOP2A升高的样品与缺乏这种酶的样品。我还将探索不同肿瘤等级的TOP2A活性。使用神经运动指导，我将研究GBM可切除部分的TOP2A的差异，并在肿瘤边缘进行探索，以探索是否可以用依托泊苷靶向大脑的肿瘤细胞。 TOP2A DNA结合和DSB是通过该酶及其依托泊苷的靶向转录调节的常见的，可能会使TOP2A在转录调节该药物的转录调节。我将在具有可变依托泊苷灵敏度的GBM细胞系上探索这种关系。为了探索Top2a在进展中的作用，我将研究转基因小鼠胶质瘤的不同时间的TOP2A转录调控。为了探索神经胶质瘤中依托泊苷引起的转录改变，我将在12小时的依托泊苷处理后研究肿瘤，并在复发中研究。总而言之，我建议表征TOP2A在GBM中的转录调控及其在进展中的作用。我将确定用于个性化肿瘤内依托泊苷治疗的分子标准，并了解转录调控对依托泊苷的破坏如何影响复发。 TOP2A作为浸润肿瘤的靶标也将被探索。总体目标是为GBM设计一个个性化的肿瘤内依托泊苷试验。