Regulation of glioblastoma migration by PTEN PDZ-binding domain

PTEN PDZ 结合域调控胶质母细胞瘤迁移

• 批准号: 7587752
• 负责人: ANDREW M CHAN
• 金额: $ 16.72万
• 依托单位: MEDICAL COLLEGE OF WISCONSIN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7587752
• 关键词: Actins; Amino Acids; Astrocytes; Behavior; Binding; Biological Assay; Brain; Brain Neoplasms; Catalytic Domain; Cell Fractionation; Cell Line; Cell membrane; Cells; Clinical; Cytoskeleton; Detergents; Development; Disease; Ectopic Expression; Epidermal Growth Factor Receptor; Event; Family; Foundations; Gene Silencing; Glioblastoma; Glioma; Gliomagenesis; Goals; Growth Factor Receptors; Histopathology; Human; Invaded; Link; Lipids; Malignant - descriptor; Malignant Neoplasms; Malignant neoplasm of brain; Mediating; Membrane; Modeling; Molecular; Molecular Target; Mouse Strains; Mus; Mutation; Nature; Oncogenes; Outcome; PDPK1 gene; PTEN gene; Phase; Phosphatidylinositol 4,5-Diphosphate; Phosphatidylinositols; Phospho-Specific Antibodies; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Platelet-Derived Growth Factor; Platelet-Derived Growth Factor Receptor; Pre-Clinical Model; Property; Protein Binding Domain; Proteins; Pseudopodia; RNA Interference; Regulation; Relative (related person); Research; Role; Signal Pathway; Signal Transduction; Small Interfering RNA; Staging; Techniques; Testing; Therapeutic; Therapeutic Intervention; Tissues; Transgenic Animals; Tumor Suppressor Proteins; attenuation; base; cell motility; drug discovery; ezrin; matrigel; member; migration; moesin; mouse model; mutant; novel; outcome forecast; overexpression; pre-clinical; public health relevance; radixin protein; research study; tool; tripolyphosphate; tumor; tumorigenesis

DESCRIPTION (provided by applicant): The long-term objective of the present proposal is to uncover novel targets for treating malignant glioblastoma. This proposal explores a novel interaction between the PI3-K signaling cascade involving PTEN, and a group of pro-metastatic proteins, Ezrin-Radixin-Moesin (ERM), in regulating the motile behavior of glioblastoma. Glioblastoma multiforme is the most malignant form of human glioma characterized by extensive local invasion. Identification of molecular targets to treat this malignancy will have an impact on the clinical outcomes. Several oncogenes have been shown to be overexpressed in glioblastoma. These include Epidermal Growth Factor Receptor (EGFR), Platelet-derived Growth Factor (PDGF), and the receptors for PDGF. In late stage glioblastoma, the most frequent genetic alteration is the loss of PTEN tumor suppressor. The molecular mechanisms responsible for the highly invasive nature of glioblastoma have not been fully elucidated. The major finding is that PTEN mediates the disassembly of motile pseudopodia in glioblastoma. This is correlated with a drastic redistribution of a membrane-cytoskeleton linker protein, moesin, and a concomitant reduction in cell motility. The regions within PTEN responsible for this activity are the phosphatase domain and the last four amino acid PSD95/Dlg/ZO-1 (PDZ)-binding domain. Interestingly, PDZ-binding domain is specifically targeted for mutation inactivation in glioblastoma. This application will develop a novel brain tumor model, Pten?PDZ, which harbors a deletion in the PTEN PDZ-binding domain to recapitulate the invasive phase of glioblastoma development. In Specific Aim 1, primary astrocytes will be prepared from both wild-type and Pten?PDZ-/- mice. The signaling cascades linking PTEN to Akt and ERM will be delineated. The activation states and subcellular distribution of ERM, PTEN, and Akt in these astrocytes will also be compared. By using ectopic expression and siRNA, the role of Akt in regulating ERM proteins will be determined. In Specific Aim 2, the migratory properties of astrocytes prepared from Pten?PDZ+/+ and Pten?PDZ-/- mice will be compared. The role of Akt and ERM proteins in cell migration will be examined by silencing RNA strategy. In Specific Aim 3, Pten?PDZ-/- mice will be crossed to a RasB8 glioma model. Gliomas generated in PasB8: Pten?PDZ+/+ and RasB8: Pten?PDZ-/- mice will be analyzed for their histological grades, invasive features and relative tumor latency. These studies will lay the foundation for the development of molecular-based therapeutics for brain tumors. PUBLIC HEALTH RELEVANCE: Human glioblastoma multiforme is a highly malignant tumor and the clinical prognosis is generally poor. This proposal explores the use of a novel preclinical mouse model to recapitulate the invasive phase of this malignant disease. The long-term goal is to use this mouse model as a drug discovery tool to identify compounds that can block the spread of human glioblastoma.

描述（由申请人提供）：本提案的长期目标是发现治疗恶性胶质母细胞瘤的新靶点。本研究探讨了涉及PTEN的PI3-K信号级联与一组促转移蛋白Ezrin-Radixin-Moesin （ERM）在调节胶质母细胞瘤运动行为中的新型相互作用。多形性胶质母细胞瘤是人类胶质瘤最恶性的形式，其特点是广泛的局部侵袭。确定治疗这种恶性肿瘤的分子靶点将对临床结果产生影响。一些癌基因已被证明在胶质母细胞瘤中过度表达。这些包括表皮生长因子受体（EGFR）、血小板衍生生长因子（PDGF）和PDGF受体。在晚期胶质母细胞瘤中，最常见的基因改变是PTEN肿瘤抑制因子的缺失。胶质母细胞瘤具有高度侵袭性的分子机制尚未完全阐明。主要发现是PTEN介导胶质母细胞瘤中活动假足的解体。这与膜-细胞骨架连接蛋白（moesin）的剧烈重新分布以及伴随的细胞运动性降低有关。PTEN中负责这种活性的区域是磷酸酶结构域和最后四个氨基酸PSD95/Dlg/ZO-1 （PDZ）结合结构域。有趣的是，pdz结合域是胶质母细胞瘤突变失活的特异性靶点。该应用程序将开发一种新的脑肿瘤模型Pten？PDZ，它包含PTEN PDZ结合域的缺失，重现胶质母细胞瘤发展的侵袭期。在特异性目标1中，将从野生型和Pten？PDZ - / -小鼠。将描述连接PTEN与Akt和ERM的信号级联。比较星形胶质细胞中ERM、PTEN、Akt的激活状态和亚细胞分布。通过异位表达和siRNA，我们将确定Akt在ERM蛋白调控中的作用。在Specific Aim 2中，Pten？PDZ+/+和Pten？将PDZ-/-小鼠进行比较。Akt和ERM蛋白在细胞迁移中的作用将通过沉默RNA策略进行研究。在《明确目标3》中，p ？PDZ-/-小鼠将与RasB8胶质瘤模型杂交。PasB8: Pten？PDZ+/+和RasB8: Pten？分析PDZ-/-小鼠的组织学分级、侵袭性特征和相对肿瘤潜伏期。这些研究将为脑肿瘤分子疗法的发展奠定基础。公共卫生相关性：人类多形性胶质母细胞瘤是一种高度恶性肿瘤，临床预后通常较差。本建议探讨使用一种新的临床前小鼠模型来概括这种恶性疾病的侵袭期。长期目标是使用这种小鼠模型作为药物发现工具，以确定可以阻止人类胶质母细胞瘤扩散的化合物。