Understanding how ZFHX4 drives the glioblastoma tumor propagating cell state

项目摘要 胶质母细胞瘤（GBM）是一种原发性脑肿瘤，可导致严重的神经功能恶化和死亡。 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。 年不可避免的复发的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。目前还没有专门针对或根除TPC的治疗方法， 对这些高抗性细胞的机理理解是有限的。我们发现了一种转录因子， TPC状态所需的ZFHX 4及其抑制显著降低小鼠的存活率 异种移植模型ZFHX 4在患者肿瘤中的表达越高，他们的寿命就越短。整体 我们建议的目的是确定为什么ZFHX 4是致癌的TPC状态所必需的，并确定 它控制着GBM功能的哪些方面。我们发现ZFHX 4与染色体结构域-解旋酶-DNA相互作用， 结合蛋白4（CHD 4），核小体重塑和脱乙酰酶（NuRD）复合物的核心成员。 此外，我们发现，像ZFHX 4一样，CHD 4需要维持TPC状态。我们最近还 发现ZFHX 4与SMARCA 3和PARP相互作用，这两者都是有效DNA修复所必需的， TPC的标志。我们假设ZFHX 4在转录水平上驱动GBM关键基因的表达， 在自我更新，生长和迁移中，并且通过与不同蛋白质的相互作用，它还在以下方面发挥作用： DNA损伤反应。在目的1中，我们将确定ZFHX 4在GBM中的基本功能和靶点。在 目的2，我们将评估ZFHX 4如何与CHD 4相互作用，并确定其生物学后果。 互动在目标3中，我们将确定为什么ZFHX 4是DNA损伤后TPC存活所必需的。我们将使用 生物化学，遗传学和细胞生物学方法，包括创新的新技术，如电话卡， 在特定条件下跟踪ZFHX 4结合位点，超分辨率共聚焦显微镜研究ZFHX 4 定位和信息结构-功能分析，以及DNA损伤激光微束，以研究 ZFHX 4在DNA损伤中的作用这些目标的成功实现将为ZFHX 4的成功提供重要的见解。 所需的TPC状态和基本知识，这种转录因子和表观遗传调控 胶质母细胞瘤这些研究将有助于阐明为什么耐药TPC会造成显著的肿瘤负荷， 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ZFHX 4功能，减少患者的TPC负担，并延长生存期。

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.