Role of Stat3alpha in mutant EGFR signaling in Glioma

Stat3alpha 在胶质瘤突变 EGFR 信号传导中的作用

• 批准号: 6792635
• 负责人: TIMOTHY S SCHAEFER
• 金额: $ 23.28万
• 依托单位: MESO SCALE DIAGNOSTICS, LLC
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-06-01 至 2006-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6792635
• 关键词: angiogenesis; apoptosis; athymic mouse; biological signal transduction; cell line; cell proliferation; epidermal growth factor; gene induction /repression; glioblastoma multiforme; growth factor receptors; molecular cloning; neoplastic growth; point mutation; protein structure function; receptor binding; receptor expression; site directed mutagenesis; terminal nick end labeling; transcription factor; transfection; xenotransplantation

DESCRIPTION: (provided by applicant) Glioblastoma multiforme (GBM) are highly vascularized tumors of the brain. One of the most frequently observed genetic alterations in GBM is the rearrangement of the epidermal growth factor receptor (EGFR). This mutation EGFRvIII, the result of exons 2-8, results in a receptor that no longer binds ligand and is constitutively activated. The expression of this receptor results in the activation of a number of signaling pathways and confers an increase in the proliferative capacity and tumorigenicity of cells expressing the receptor. Signal transducers and activators of transcription (Stat) proteins are a family of latent transcription factors normally activated by numerous cytokines and growth factors. One member of the family, Stat3, has been implicated in aberrant cell proliferation and constitutively activated Stat3cx has been seen in several types of neoplastic cells and solid tumors. In experiments designed to explore Stat3 signaling in human brain tumors, we have found that Stat3a is constitutively activated in low- and high-grade glioma (compared to normal brain tissue). In other preliminary experiments, we have demonstrated a direct interaction between Stat3a and EGFRvIII in extracts from cells that express both proteins. The expression of EGFRvIII leads to the activation of Stat3a with a concomitant increase in Stat3a-mediated transcription and this activation required serine phosphorylation on serine residue 727 indicating a convergence of more than one signaling event in Stat3a activation by EG FRvIII. In experiments described here, we propose to determine the role of Stat3a in the growth properties imparted by EGFRvIII expression both in vitro and in vivo using EGFRvIII derived mutants that cannot activate Stat3a and by the use of dominant-negative Stat3a molecules to directly block Stat3cx mediated signaling. The in vitro studies will be performed using cultured glioma cells that express EGFRvIII while the In vivo experiments will be performed using a novel intracranial induction system developed in our laboratory.

描述：（申请人提供） 胶质母细胞瘤多形（GBM）是大脑的高度血管化肿瘤。一 GBM中最常见的遗传改变是重排 表皮生长因子受体（EGFR）的这个突变egfrviii， 外显子2-8的结果，导致受体不再结合配体，并且IS 组成性激活。该受体的表达导致 激活许多信号通路，并赋予增加 表达受体的细胞的增殖能力和致瘤性。 信号换能器和转录激活因子（STAT）蛋白是一个家族 通常由许多细胞因子激活的潜在转录因子和 增长因素。一名家庭成员STAT3与 已经看到异常细胞增殖和组成型激活的STAT3CX 在几种类型的肿瘤细胞和实体瘤中。在设计实验中 探索人脑肿瘤中的STAT3信号传导，我们发现STAT3A是 在低级和高级神经胶质瘤中的组成性激活（与正常 脑组织）。在其他初步实验中，我们证明了一个直接的 STAT3A和EGFRVIII之间的相互作用在表达细胞的提取物中 两种蛋白质。 EGFRVIII的表达导致Stat3a的激活 随着STAT3A介导的转录的同时增加，这 激活需要在丝氨酸残基上的丝氨酸磷酸化727，表明 EG FRVIII激活STAT3A激活中多个信号事件的收敛。 在此处描述的实验中，我们建议确定Stat3a在 EGFRVIII表达在体外和体内赋予的生长特性 使用无法激活STAT3A并使用的EGFRVIII派生的突变体 显性阴性STAT3A分子直接阻止STAT3CX介导 信号。体外研究将使用培养的神经胶质瘤细胞进行 在体内实验时将使用A表达EGFRVIII 我们实验室开发的新型颅内诱导系统。