Targeting Glioblastoma Stem Cells through Epigenetic Reprogramming

标题：通过表观遗传重新编程靶向胶质母细胞瘤干细胞 摘要： 摘要胶质母细胞瘤(Gbm)是成人最常见的恶性脑肿瘤，临床表现较差。 结果。在治疗这一致命疾病方面缺乏革命性的改进 在过去的40年里，疾病。任何可以显著延长患者整体生活质量的治疗 存活三个月以上，这是迄今为止治疗GBM的最好成绩 使用手术、放射治疗和替莫唑胺，可以被认为是成功的。我们的长- 学期目标是为这种致命疾病开发新的治疗策略。GBM癌症干细胞- 类细胞(CSCs)最近被几个组前瞻性地分离并显示出耐药 常规的放射治疗和化疗。CSCs靶向治疗带来希望 脑瘤患者。Notch信号是一种发育信号通路，一直以来 在GBM CSCs中发现被激活。我们已经证明，Notch抑制会耗尽GBM CSCs 并延长小鼠移植脑内GBM的存活时间。最近的一项I期临床试验 研究表明，四分之一的恶性胶质瘤患者病情稳定时间超过 Notch抑制剂治疗后4个月。然而，介导Notch的靶点被调控 GBM CSC的自我更新在很大程度上是未知的。当CSCs产生非CSC细胞时，主要 两者之间的区别是受表观遗传学调控的基因表达水平不同，如 如DNA甲基化和组蛋白修饰，包括乙酰化。我们的初步数据来自 Notch抑制剂处理GBM神经球的微阵列分析表明，表观遗传学 组蛋白脱乙酰酶4因子(DHAC4)受Notch信号调控。此外，我们的 初步研究表明，HDAC4是GBM神经球增殖所必需的 体外和体内。为了制定新的目标来消耗GBM CSCs，目前的提案将 探讨Notch调控HDAC4的分子机制及其对GBM的影响 CSCS及其翻译应用。 在特定的目标#1中，我们将定义不同蛋白结构域的功能效应 GBM CSCs上的HDAC4。 在具体目标2中，我们将定义Notch和HDAC4交互作用在自我 续签GBM CSCs。 在特定的目标#3中，我们将检查Notch和HDAC4抑制疗法的组合 在GBM患者来源的原位异种移植(PDX)中。 当前提案的成功不仅将发现表观遗传因素HDAC4 调节GBM CSCs的自我更新，提高GBM的治疗效果，也将对临床有一定的意义 对癌症治疗的总体影响。

Title: Targeting Glioblastoma Stem Cells through Epigenetic Reprogramming ABSTRACT: Glioblastoma (GBM) is the most common malignant brain tumor in adult with poor clinical outcome. There has been a lack of revolutionary improvement in treatment of this deadly disease over the past 40 years. Any treatment that can significantly prolong patients' overall survival for more than three months, which is the best achievement so far to treat GBM when using surgery, radiation therapy and temozolomide, can be considered as a success. Our long- term goal is to develop novel therapeutic strategies for this lethal disease. GBM cancer stem- like cells (CSCs) were recently prospectively isolated by several groups and showed resistance to conventional radiation therapy and chemotherapy. Targeting CSCs therapy brings a hope for brain tumor patients. The Notch signaling is a developmental signaling pathway that has been found activated in GBM CSCs. We have demonstrated that Notch inhibition deplete GBM CSCs and prolong survival in mice bearing intracranial GBM xenografts. A recent Phase I clinical trial study shows that a quarter of malignant glioma patients have stabilized disease for more than four month after Notch inhibitor treatment. However, the targets that mediate Notch regulated GBM CSC self-renewal are largely unknown. As CSCs give rise to non-CSC cells, the major difference between the two is a different level of gene expression regulated by epigenetics, such as DNA methylation and histone modification, including acetylation. Our preliminary data from microarray analysis on Notch inhibitor treated GBM neurosphere showed that an epigenetic factor Histone deacetylase 4 (DHAC4) is regulated by Notch signaling. Furthermore, our preliminary studies showed that that HDAC4 is required for GBM neurosphere propagation in vitro and in vivo. In order to develop new targets to deplete GBM CSCs, the current proposal will examine the molecular mechanism by which Notch regulates HDAC4 and its impact on GBM CSCs, and its translational application. In specific Aim #1, we will define the functional effect of different protein domains of HDAC4 on GBM CSCs. In specific Aim #2, we will define the role of Notch and HDAC4 interaction on self- renewal of GBM CSCs. In specific Aim #3, we will examine a combination of Notch and HDAC4 inhibition therapy in GBM patient-derived orthotopic xenografts (PDXs). Successes in the current proposal will not only discover how an epigenetic factor HDAC4 regulates self-renewal of GBM CSCs and improve GBM treatment, but also will have a clinical impact on cancer therapy in general.