Imaging of gene expression in glioblastoma

描述(申请人提供)：正常大脑和其胶质起源的肿瘤之间的基因表达模式的差异可以为恶性胶质瘤的诊断和治疗提供有用的信息。这些肿瘤在核磁共振扫描上可见之前无法诊断，目前无法治疗(患者的平均生存期=6-12个月)。通过基因图谱分析方法，如基因表达序列分析(SAGE)，可以获得胶质瘤肿瘤形成和恶性进展的标志物。最近，通过癌症基因组解剖计划(CGAP)的努力，恶性胶质瘤(GBM)的SAGE数据已经成为可能，并发现了几个在GBM中高表达而在正常脑中不表达的基因。这些信息可以被用来设计选择性标志物，用于这些肿瘤的成像和治疗。具体地说，本项目提出：1-验证候选的SAGE鉴定的GBM基因在GBM中是否真的过表达，2-从转录过度活跃的基因中分离相关的启动子片段，以及3-测试克隆的转录过度活性启动子在体外和体内模型中为成像和治疗提供GBM特异性cDNAs的能力。关于GBM特异性基因的SAGE数据将在GBM肿瘤细胞中得到验证，并使用激光捕获显微解剖和定量RT-PCR分析与正常细胞进行比较。将对真正过度表达的基因进行调查，并排除转录以外可能导致过度表达的事件。候选基因的启动子序列将通过包含候选基因基因组序列的适当细菌人工染色体(BAG)来分离。一种将这些BAC转化为感染载体的新方法将被用于研究和确认GBM细胞中启动子的功能和选择性。然后，GBM的过度活性和选择性启动子将被用来指导胶质瘤细胞中成像cDNAs和/或自杀基因的转录，首先是在组织培养中，然后是在癌症的体内模型中。这些研究将为将CGAP数据转化为有用的诊断和治疗方式提供一条途径，不仅适用于脑部恶性肿瘤，也适用于其他肿瘤。这里提出的概念方案也潜在地适用于可获得基因图谱分析的各种疾病。

DESCRIPTION (provided by applicant): Differences in the pattern of gene expression between normal brain and its tumors of glial origin can provide information useful for malignant glioma diagnosis and therapy. These tumors cannot be diagnosed until they become visible on MRI scans and cannot be currently treated (mean survival of patients = 6-12 months). Markers for glioma tumor formation and malignant progression are becoming available through gene profiling methods, such as serial analysis of gene expression (SAGE). Recently, SAGE data for malignant glioma (GBM) has become available through efforts of the Cancer Genome Anatomy Project (CGAP) and several genes have been identified that are over-expressed in GBM and not in normal brain. This information can be exploited to design selective markers for imaging and treatment of these tumors. Specifically, this project proposes to: 1- Verify that candidate SAGE-identified GBM genes are truly overexpressed in GBMs, 2- Isolate the relevant promoter fragments from transcriptionally overactive genes, and 3-Test the ability of cloned transcriptionally over-active promoters to provide GBM-specific cDNA expression for imaging and therapy in both.in vitro and in vivo models. SAGE data on GBM-specific genes will be verified in GBM tumor cells and compared to normal cells using laser-capture microdissection and quantitative RT-PCR analyses. Truly overexpressed genes will be investigated and events other than transcription that may be causing overexpression will be ruled out. Promoter sequences of candidate genes will be isolated through the appropriate bacterial artificial chromosome (BAG) containing the genomic sequence of the candidate genes. A novel method of converting these BACs into infectious vectors will be used to study and confirm promoter functionality and selectivity in GBM cells. GBM overactive and selective promoters will then used to direct transcription of an imaging cDNA and/or of a "suicide" gene in glioma cells, first in tissue culture and then in in vivo models of cancer. These studies will provide an avenue for translating CGAP data into useful diagnostic and therapeutic modalities not only for malignant tumors in the brain, but also for other tumors. The conceptual scheme presented herein is also potentially applicable to a variety of diseases for which gene profiling analyses is available.