Neural Progenitor Genes and Brain Tumors

描述（由申请方提供）：多形性胶质母细胞瘤（GBM）几乎普遍具有致死性。具有自我更新能力的肿瘤起始细胞（有时称为“癌症干细胞”）的发现为开发新的治疗途径创造了巨大的热情。这些细胞利用熟悉的途径进行增殖，例如PI 3激酶途径。尽管脑肿瘤干细胞样细胞的发现带来了希望，但在治疗发展的道路上存在许多障碍。一个复杂的问题是，这些细胞对常规疗法和抑制途径具有显著的抗性。另一个是不同患者肿瘤中存在的脑肿瘤干细胞样细胞之间存在差异。本研究的目的是严格检查脑肿瘤干细胞样细胞生物学，以开发攻击它们的方法并克服它们的抵抗机制。首先，我们将通过使用癌症基因组图谱（TCGA）的最新进展来研究GBM干细胞样细胞的异质性。我们将从患者中获取样本，并根据通过基因表达分析定义的分子亚类对其进行分组。我们将评估这些细胞在体外产生神经球以及在异种移植物中形成肿瘤的能力。然后，我们将使用药理学和基因操作策略来确定GBM干细胞样细胞对PI 3 K通路不同节点的依赖性。我们将确定TCGA定义的四个亚组--神经、前神经、间充质和经典--是否对这些淋巴结的增殖和肿瘤发生具有不同程度的依赖性。接下来，我们将评估PI 3 K通路在介导脑肿瘤干细胞样细胞中观察到的增强的辐射抗性中的作用。我们将测试的假设，激活的途径导致在体外增强抗辐射，并确定我们是否可以通过抑制特定的通路组件逆转这种阻力。然后，我们将测试的假设，途径激活促进辐射抗性的机制之一是通过激活Nrf 2氧化应激反应机制。然后，我们将探讨GBM干细胞样细胞的化学抗性机制。我们将使用细胞培养，体内测定和一种新的基于微流体的免疫细胞化学分析（MIC）系统来确定雷帕霉素是否选择具有增强的致瘤性和通路激活的干细胞样细胞。我们还将确定是否可以通过抑制过度活化的途径来克服对雷帕霉素治疗的耐药性。然后，我们将确定新的耐药途径的基础上完成磷酸化蛋白质组学筛选，以发现蛋白质的磷酸化或去磷酸化的雷帕霉素耐药性的发展。我们将确定通过该筛选鉴定的蛋白质在抗性发展中的潜在作用。这些合作研究将为更深入地了解GBM生物学铺平道路，并为GBM的机制和治疗提供未来的临床和转化研究。

DESCRIPTION (provided by applicant): Glioblastoma multiforme (GBM) is almost universally fatal. The discovery of tumor-initiating cells with the capacity to self-renew, sometimes termed "cancer stem cells", has created tremendous enthusiasm for the development of new avenues of therapy. These cells utilize familiar pathways for their proliferation, such as the PI3 Kinase pathway. Despite the hope raised by the discovery of brain tumor stem cell-like cells, numerous obstacles lie in the path of therapeutic development. One complication is that these cells have significant resistance to conventional therapies and to inhibition of pathways. Another is that there are differences amongst brain tumor stem-like cells that are present in the tumors of different patients. The goals of this study are to critically examine brain tumor stem cell-like cell biology in order to develop the means to attack them and to overcome their mechanisms of resistance. First, we will examine the heterogeneity of GBM stem cell-like cells through the use of recent advances by the The Cancer Genome Atlas (TCGA). We will obtain samples from patients and group them according to molecular subclasses defined through the analysis of gene expression. We will evaluate the ability of these cells to give rise to neurospheres in vitro as well as to form tumors in xenografts. We will then use a pharmacologic and gene manipulation strategy to determine the dependence of GBM stem cell-like cells on different nodes of the PI3K pathway. We will determine whether the four subgroups defined by the TCGA--Neural, Proneural, Mesenchymal and Classical--confer different levels of dependency on these nodes for proliferation and tumorigenesis. We will next assess the role of the PI3K pathway in mediating the enhanced resistance to radiation observed in brain tumor stem cell-like cells. We will test the hypothesis that activation of the pathway results in enhanced resistance to radiation in vitro and determine whether we can reverse this resistance through inhibition of specific pathway components. Then we will test the hypothesis that one of the mechanisms by which pathway activation promotes radiation resistance is through the activation of the Nrf2 oxidative stress-response mechanism. We will then explore mechanisms of chemoresistance in GBM stem cell-like cells. We will use cell culture, in vivo assays and a new microfluidicsbased immunocytochemical analysis (MIC) system to determine whether rapamycin selects for stem cell-like cells with enhanced tumorigenicity and pathway activation. We will also determine whether resistance to rapamycin treatment can be overcome through inhibition of hyperactivated pathways. Then, we will identify novel pathways of resistance based on a completed phosphoproteomic screen to discover proteins that are phosphorylated or dephosphorylated during the development of rapamycin resistance. We will determine the potential role of the proteins identified by this screen in the development of resistance. These collaborative studies will pave the way for a deeper understanding of GBM biology and inform future clinical and translational and clinical research into the mechanisms and treatment of GBM.