Genetic Analysis of EGFRvIII-independent Glioblastoma Maintenance

不依赖 EGFRvIII 的胶质母细胞瘤维持的遗传分析

基本信息

批准号：
8205441
负责人：
Tiffany Elizabeth Taylor
金额：
$ 3.38万
依托单位：
LUDWIG INSTITUTE FOR CANCER RES LTD
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-01 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8205441
关键词：
Adjuvant Therapy Adult Apoptosis Apoptotic Brain Brain Neoplasms Cell Line Clinical Clinical Treatment Clinical Trials Cues Data Data Reporting Development Disease Drug resistance Epidermal Growth Factor Receptor Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor Event Excision Exons Gene Expression Gene Expression Profile Genes Genetic Genetic Models Glioblastoma Glioma Goals Growth Induction of Apoptosis Knowledge Light Maintenance Malignant Glioma Malignant Neoplasms Mediating Microarray Analysis Molecular Molecular Profiling Mutation Non-Small-Cell Lung Carcinoma Oncogenic Operative Surgical Procedures Outcome Patients Pharmaceutical Preparations Phenotype Point Mutation Primary Brain Neoplasms Publishing Receptor Inhibition Receptor Protein-Tyrosine Kinases Residual Tumors Resistance Route Testing Tetracyclines Therapeutic Translating Tumor Cell Line Tyrosine Kinase Inhibitor Variant Work aurora-A kinase base c-erbB-1 Proto-Oncogenes cancer type clinically relevant combinatorial effective therapy epidermal growth factor receptor VIII genetic analysis improved in vivo insight loss of function mutant receptor receptor expression receptor function resistance mechanism small molecule standard care sulfated glycoprotein 2 tumor

项目摘要

DESCRIPTION (provided by applicant): Amplification and mutation of the epidermal growth factor receptor (EGFR) gene are common genetic hallmarks of glioblastoma multiforme (GBM). The most common mutation is an in-frame deletion of exons 2-7, resulting in a constitutively active variant of the receptor, EGFRvIII/ EGFR (herein refered to as EGFR). Therapies that target EGFR and EGFR, such as small molecule tyrosine kinase inhibitors (TKIs), are currently in clinical trials for the treatment of GBM. However, their efficacy has been limited due to both upfront and acquired drug resistance. Thus, it seems that blocking these molecules alone may not sufficiently translate into a clinical benefit for GBM patients. Using a genetic model of tetracycline-regulated EGFR expression, the lab previously demonstrated that this receptor is esential for the maintenance of glioma growth in vivo. However, similar to a clinical situation of acquired drug resistance, some tumors eventually regained aggressive growth after a period of stasis. Surprisingly, these breakthrough tumors persisted despite sustained suppression of EGFR, were substantially more resistant to apoptosis compared to EGFR-dependent tumors, and cell lines generated from these tumors were resistant to EGFR TKIs even when EGFR was re- expressed. Gene expression profiles of EGFR-independent cell lines generated using microarray technology revealed that a number of genes were significantly up-regulated compared to EGFR-dependent cell lines. To identify likely candidates that may be responsible for EGFR-independent in vivo growth and maintenance, the array data was screened using the following criteria: (1) clinical relevance in GBM, (2) association with decreased apoptosis and disease, and (3) drug-targetable. From this screen, the focus was directed toward two apoptosis-related genes: Aurora kinase A (AURKA) and Clusterin (CLU). The proposed project aims to test the hypothesis that an anti-apoptotic expression signature unique to the EGFR-independent phenotype not only supports EGFR-independent tumor maintenance but may also contribute to EGFR TKI resistance. Specifically, Aim 1 wil determine the genetic requirement for EGFR-independent tumor maintenance by conducting loss of function studies. Aim 2 will determine the necessity and sufficiency of these genes to confer resistance to EGFR receptor inhibition by conducting loss of function studies in the presence of EGFR TKIs. Taken together, this study will shed light on molecular mechanisms that can serve as alternative escape routes utilized by gliomas to overcome blockade of EGFR, which wil be invaluable to the development of more effective therapies for GBM patients. PUBLIC HEALTH RELEVANCE: Glioblastoma multiforme (GBM), a WHO Grade IV astrocytoma and the most common and most aggressive type of primary brain tumor in adult humans, has proven to be largely resistant to the multiple treatment approaches. This project focuses on identifying and targeting secondary factors that become relevant in GBM once the primary oncogenic event, EGFR, has been silenced. As a result, strategies for overcoming resistance to EGFR-targeted therapies may be impacted in such a way that the departure from the status quo of using single-based EGFR-directed therapies will provoke the development of more efficacious combinatorial therapies to improve the clinical outcome for GBM patients.

描述（由申请人提供）：表皮生长因子受体（EGFR）基因的扩增和突变是多形胶质母细胞瘤（GBM）的常见遗传标志。最常见的突变是外显子2-7的框架缺失，导致受体的组成型活性变体EGFRVIII/ EGFR（以下称为EGFR）。靶向EGFR和EGFR的疗法，例如小分子酪氨酸激酶抑制剂（TKI），目前正在临床试验中用于治疗GBM。但是，由于前期和获得的耐药性，它们的功效受到限制。因此，似乎仅阻止这些分子可能无法充分转化为GBM患者的临床益处。使用四环素调节的EGFR表达的遗传模型，该实验室先前证明了该受体在体内维持神经胶质瘤的生长。但是，类似于获得耐药性耐药性的临床状况，一些肿瘤最终在停滞后恢复了侵略性生长。令人惊讶的是，尽管EGFR持续抑制，但与EGFR依赖性肿瘤相比，这些突破性肿瘤仍然持续存在，对凋亡具有更大的抵抗力，并且即使抗EGFR，这些肿瘤产生的细胞系也对EGFR TKIS具有抗性。使用微阵列技术生成的EGFR独立细胞系的基因表达谱图表明，与EGFR依赖性细胞系相比，许多基因显着上调。为了确定可能导致EGFR独立于体内生长和维持的候选者，使用以下标准筛选了阵列数据：（1）GBM中的临床相关性，（2）（2）与凋亡和疾病降低以及（3）可依赖药物的临床相关性。从这个屏幕上，焦点是针对两个与凋亡相关的基因：Aurora激酶A（Aurka）和簇蛋白（CLU）。拟议的项目旨在检验以下假设：独立于EGFR的表型独有的抗凋亡表达特征不仅支持EGFR独立的肿瘤维持，而且可能有助于EGFR TKI抗性。具体而言，AIM 1 WIL通过进行功能研究的丧失来确定对EGFR独立的肿瘤维持的遗传需求。 AIM 2将确定这些基因在存在EGFR TKI的情况下进行功能研究的丧失来赋予EGFR受体抑制的必要性和充分性。综上所述，这项研究将阐明分子机制，这些机制可以用作神经胶质瘤利用的替代性逃生路线，以克服对EGFR的阻塞，这对于为GBM患者开发更有效的疗法是无价的。公共卫生相关性：胶质母细胞瘤（GBM），WHO IV级星形胶质细胞瘤以及成人人类中最常见，最具侵略性的原发性脑肿瘤类型，已被证明对多种治疗方法具有很大的抵抗力。该项目的重点是识别和靶向二级因素，这些因素一旦主要的致癌事件EGFR已被沉默。结果，克服对EGFR靶向疗法的抵抗力的策略可能会受到影响，以使使用基于单个基于EGFR的EGFR指导疗法的现状偏离，这会引起更有效的组合疗法的发展，以改善GBM患者的临床结果。