Understanding how ZFHX4 drives the glioblastoma tumor propagating cell state

项目摘要 胶质母细胞瘤(GBM)是一种导致神经严重恶化和死亡的原发脑肿瘤。 经最大限度治疗的胶质母细胞瘤(GBM)平均在6个月内复发，大多数人在不到2个月内死亡 好几年了。不可避免的复发的一个主要原因可能是肿瘤增殖细胞(TPC)的存在， 有时被称为癌症干细胞。目前没有专门针对或根除TPC的治疗方法，而我们的 对这些高抗性细胞的机械理解是有限的。我们发现了一个转录因子， ZFHX4，这是TPC状态所必需的，它的抑制显著延长了小鼠的存活 异种移植模型。ZFHX4在患者肿瘤中的表达越高，生存期越短。整体而言 我们建议的目标是确定为什么致癌的TPC状态需要ZFHX4，并确定 它控制着GBM功能的哪些方面。我们发现ZFHX4与染色域-解旋酶-DNA相互作用。 结合蛋白4(CHD4)，核小体重塑和脱乙酰酶(NuRD)复合体的核心成员。 此外，我们发现，与ZFHX4一样，CHD4也是维持TPC状态所必需的。我们最近也是 发现ZFHX4与SMARCA3和PARP相互作用，这两种基因都是有效DNA修复所必需的 TPC的标志。我们假设ZFHX4转录驱动相关的关键GBM基因的表达 在自我更新、生长和迁移中，通过与不同的蛋白质相互作用，它也在 DNA损伤反应。在目标1中，我们将确定ZFHX4在GBM中的基本功能和目标。在……里面 目的2，我们将评估ZFHX4与CHD4的相互作用，并确定它们的生物学后果 互动。在目标3中，我们将确定为什么DNA损伤后TPC存活需要ZFHX4。我们将使用 生化、遗传和细胞生物学方法，包括创新的新技术，如电话卡 特定条件下追踪ZFHX4结合部位，超分辨共聚焦显微镜研究ZFHX4 定位和信息结构-功能分析，以及DNA损伤激光微束的作用研究 ZFHX4在DNA损伤中的作用这些目标的成功执行将为ZFHX4为什么 TPC状态所需，以及关于该转录因子和表观遗传调控的基础知识 在胶质母细胞瘤中。这些研究将有助于阐明为什么治疗耐药的TPC会导致严重的 神经系统疾病。我们的发现将产生重大影响，因为它们最终将导致治疗 抑制ZFHX4功能，减轻患者TPC负担，延长生存期。

Project Summary Glioblastoma (GBM) is a primary brain tumor that causes significant neurological deterioration and death. Maximally treated glioblastoma (GBM) recurs in 6 months on average, and it kills most people in less than 2 years. A major reason for inevitable recurrence may be the existence of tumor propagating cells (TPCs), sometimes known as cancer stem cells. No current therapy specifically targets or eradicates TPCs, and our mechanistic understanding of these highly resistant cells is limited. We discovered a transcription factor, ZFHX4, that is required for the TPC state, and its suppression significantly prolongs survival in a mouse xenograft model. The higher the expression of ZFHX4 in patient tumors, the shorter they live. The overall objective of our proposal is to determine why ZFHX4 is required for the oncogenic, TPC state and to determine which aspects of GBM function it controls. We found that ZFHX4 interacts with chromodomain-helicase-DNA- binding protein 4 (CHD4), a core member of the nucleosome remodeling and deacetylase (NuRD) complex. Moreover, we found that, like ZFHX4, CHD4 is required to maintain the TPC state. We also recently discovered that ZFHX4 interacts with SMARCA3 and PARP, which are both required for efficient DNA repair, a hallmark of TPCs. We hypothesize that ZFHX4 transcriptionally drives expression of key GBM genes involved in self-renewal, growth, and migration, and that through interactions with distinct proteins, it also plays a role in DNA damage response. In Aim 1, we will determine the essential function and targets of ZFHX4 in GBM. In Aim 2, we will evaluate how ZFHX4 interacts with CHD4, and determine the biological consequences of their interaction. In Aim 3, we will determine why ZFHX4 is required for TPC survival after DNA damage. We will use biochemical, genetic, and cell biological approaches, including innovative new technologies like calling cards to track ZFHX4 binding sites under specific conditions, super-resolution confocal microscopy to study ZFHX4 localization and inform structure-function analyses, and DNA damaging laser microbeams to study the role of ZFHX4 in DNA damage. Successful execution of these aims will provide important insight into why ZFHX4 is required for the TPC state and fundamental knowledge about this transcription factor and epigenetic regulation in glioblastoma. These studies will help clarify why therapy resistant TPCs cause a significant burden of neurological disease. Our findings will have a significant impact because they will eventually lead to treatments that inhibit ZFHX4 function, reduce the TPC burden in patients, and extend survival.