Glypican-1 in gliomagenesis

Glypican-1 在神经胶质瘤发生中的作用

• 批准号: 8540510
• 负责人: ANDREAS FRIEDL
• 金额: --
• 依托单位: WM S. MIDDLETON MEMORIAL VETERANS HOSP
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2017-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8540510
• 关键词: Age; Aneuploidy; Animals; Astrocytes; Biological Assay; Biology; Brain Neoplasms; CDKN2A gene; Cell Cycle; Cell Cycle Regulation; Cell surface; Cells; Common Neoplasm; Cyclin E; Cyclin-Dependent Kinase Inhibitor; DNA; DNA Damage; DNA Replication Damage; DNA biosynthesis; Data; Development; Diagnosis; Endothelial Cells; Event; Future; G1/S Transition; Genetic; Glial Fibrillary Acidic Protein; Glioma; Gliomagenesis; Glypican; Growth; Health; Heparan Sulfate Proteoglycan; Human; In Vitro; Laboratories; Lead; Malignant - descriptor; Mediator of activation protein; Morbidity - disease rate; Mus; Mutation; Neoplasms; Neuraxis; Neuroglia; Oncogenes; Pathway Analysis; Patients; Penetrance; Play; Population; Prevention; Process; Prognostic Marker; Proteoglycan; Relative (related person); Research Design; Resistance; Retinoblastoma Protein; Role; S Phase; Signal Pathway; Signaling Molecule; System; Testing; Therapeutic Intervention; Tissue Microarray; Transgenic Mice; Veterans; Virus Receptors; base; c-myc Genes; design; gain of function; human CDK2 protein; in vivo; in vivo Model; insight; killings; loss of function; mortality; nerve stem cell; novel; novel strategies; oncoprotein p21; outcome forecast; overexpression; ras Oncogene; research study; treatment strategy; tumorigenesis

DESCRIPTION (provided by applicant): Central nervous system gliomas cause morbidity and mortality by relentless growth and local invasion. High-grade gliomas typically kill patients within months after diagnosis. Despite advances in therapy, this dismal prognosis has not changed significantly. One of the hallmarks of glioma cells is their genetic instability, which contributes to progression and therapy resistance. A major barrier to the development of more effective glioma treatment strategies is the relative lack of understanding of the mechanisms underlying glioma development, progression and genetic instability. We have made a discovery that may offer a novel approach to the treatment of gliomas. Our laboratory discovered that glypican-1 (GPC1), a cell surface proteoglycan, is overexpressed in the vast majority of gliomas. Overexpression of GPC1 in vitro activates c-Myc and triggers the Skp2 autoinduction loop, which is characterized by the coordinated induction of E2F, Skp2, cyclin E and cyclin-dependent kinase 2 (CDK2) and the suppression of the cyclin-dependent kinase inhibitors (CKIs) p21 and p27. These coordinated changes in cell cycle regulators lead to G1-S-transition and DNA replication. In glioma cells and astrocytes, GPC1 overexpression also induces DNA re-replication resulting in DNA damage. Preliminary data indicate that the oncogene c-Myc plays is a major upstream mediator of these changes. We hypothesize that GPC1 is a potent regulator of the cell cycle and acts as an oncogene when overexpressed in glial cells. We propose to test this hypothesis by deciphering the signaling pathway of GPC1 in glioma cells and astrocytes and by determining the effect of GPC1 loss and overexpression on glioma development in vivo. Aim 1: Analyze the mechanism of Gpc1 in cell cycle regulation: We will analyze the effect of different GPC1 concentrations on DNA replication and cell cycle regulators in astrocytes and different glioma cells. A particular focus will be placed on GPC1 activity in the activation of c-Myc. In addition, we will employ a discovery strategy to identify GPC1 interaction partners. Aim 2: Analyze the ability of GPC1 to transform human astrocytes: Immortal and primary human astrocytes will be transduced to overexpress GPC1. The malignant potential of the cells will be assessed in in vitro transformation assay and with in vivo tumorigenesis experiments. Aim 3: Determine the role of GPC1 in glioma development and progression in vivo: The role of GPC1 in early gliomagenesis will be assessed using state-of-the-art in vivo models based on the RCAS tv-a viral receptor system. Using a gain-of-function approach, GPC1 will be overexpressed in neural progenitors and astrocytes to determine whether GPC1 is sufficient for glioma induction. Using a loss-of-function approach, genetically GPC1-deficient mice will be crossed with transgenic mice, which express activated ras oncogene in a astrocyte-specific manner and which develop high-grade gliomas with high penetrance and short latency. These experiments will reveal whether GPC1-deficient animals are protected from gliomagenesis. In addition, we will interrogate an existing tissue microarray to determine whether GPC1 overexpression is an independent prognostic marker in human glioma. Significance: The proposed studies are designed to offer novel insights into the biology of glioma development and progression and into the specific role of the proteoglycan GPC1 in these processes. The GPC1 signaling pathway may offer opportunities for therapeutic intervention by targeting either GPC1 itself or downstream mediators.

描述（由申请人提供）： 中枢神经系统神经胶质瘤通过持续生长和局部侵袭导致发病和死亡。高级别神经胶质瘤通常在诊断后数月内导致患者死亡。尽管治疗取得了进展，但这种令人沮丧的预后并没有显着改变。神经胶质瘤细胞的标志之一是其遗传不稳定性，这会导致进展和治疗耐药。开发更有效的神经胶质瘤治疗策略的一个主要障碍是对神经胶质瘤发生、进展和遗传不稳定性的机制相对缺乏了解。我们的一项发现可能为治疗神经胶质瘤提供一种新方法。 我们的实验室发现磷脂酰肌醇蛋白聚糖-1 (GPC1)，一种细胞表面蛋白聚糖，在绝大多数神经胶质瘤中过度表达。 GPC1 体外过表达会激活 c-Myc 并触发 Skp2 自诱导环，其特征是协调诱导 E2F、Skp2、细胞周期蛋白 E 和细胞周期蛋白依赖性激酶 2 (CDK2)，并抑制细胞周期蛋白依赖性激酶抑制剂 (CKIs) p21 和 p27。细胞周期调节因子的这些协调变化导致 G1-S 转变和 DNA 复制。在神经胶质瘤细胞和星形胶质细胞中，GPC1 过度表达还会诱导 DNA 重新复制，从而导致 DNA 损伤。初步数据表明，癌基因 c-Myc 是这些变化的主要上游调节因子。 我们假设 GPC1 是细胞周期的有效调节因子，并且当在神经胶质细胞中过度表达时充当癌基因。我们建议通过破译神经胶质瘤细胞和星形胶质细胞中 GPC1 的信号通路以及确定 GPC1 丢失和过度表达对神经胶质瘤体内发育的影响来检验这一假设。目的1：分析Gpc1在细胞周期调节中的机制：我们将分析不同浓度的GPC1对星形胶质细胞和不同胶质瘤细胞中DNA复制和细胞周期调节剂的影响。将特别关注 c-Myc 激活中的 GPC1 活性。此外，我们将采用发现策略来识别 GPC1 交互伙伴。目标 2：分析 GPC1 转化人星形胶质细胞的能力：永生和原代人星形胶质细胞将被转导以过表达 GPC1。将通过体外转化测定和体内肿瘤发生实验来评估细胞的恶性潜力。目标 3：确定 GPC1 在体内神经胶质瘤发生和进展中的作用：将使用基于 RCAS tv-a 病毒受体系统的最先进的体内模型来评估 GPC1 在早期神经胶质瘤发生中的作用。使用功能获得方法，GPC1 将在神经祖细胞和星形胶质细胞中过度表达，以确定 GPC1 是否足以诱导神经胶质瘤。使用功能丧失方法，遗传上 GPC1 缺陷的小鼠将与转基因小鼠杂交，转基因小鼠以星形胶质细胞特异性方式表达激活的 ras 癌基因，并形成具有高外显率和短潜伏期的高级神经胶质瘤。这些实验将揭示 GPC1 缺陷的动物是否能够免受神经胶质瘤发生的影响。此外，我们将询问现有的组织微阵列，以确定 GPC1 过度表达是否是人类神经胶质瘤的独立预后标志物。 意义：拟议的研究旨在为神经胶质瘤发生和进展的生物学以及蛋白多糖 GPC1 在这些过程中的具体作用提供新的见解。 GPC1 信号通路可能通过针对 GPC1 本身或下游介质来提供治疗干预的机会。