Microenvironment: Imaging/Implications in Brain Tumors

描述（由申请人提供）：已使用体外研究、临床前模型和人类肿瘤广泛描述了缺氧对肿瘤生理学和对放射治疗反应的影响。关于缺氧对分子信号传导的调节的研究还不太先进，大多数已发表的研究结论是在细胞或亚细胞系统中进行的。尽管在高级别胶质脑肿瘤中观察到异常的血管和假性扁平坏死区域，但很少注意缺氧在其进展机制中的作用。然而，最近，缺氧在脑肿瘤进展和侵袭性中的中心作用已被假设为基于WHO 4级神经胶质瘤的病理检查由Brat等人。在假扁平坏死区域染色。我们已经开发了直接和更具体地测量缺氧的方法，从所有等级的人类脑癌组织活检为基础的免疫组织化学（IHC）分析EF 5结合。当前申请建议将我们基于活检的分析扩展到[F-18]-EF 5的PET研究，并将患者结局与[F-18]-EF 5数据和基于IHC的终点进行比较（具体目标1）。在我们的第二个特定目标中，从这些患者获得的组织以及从先前用EF 5治疗的患者存档的组织将用于研究导致肿瘤抗性或细胞缺氧耐受的生理和分子缺氧依赖性机制。将使用我们实验室开发的荧光图像软件对EF 5、PECAM/CD 31（血管）、TUNEL（细胞凋亡）和Ki 67（增殖）染色的冷冻切片进行分析。在我们的第三个具体目标，组织微阵列（TMAs）将被构建来评估微环境对分子信号通路的影响。在完成这项授权时，我们将比较经验证的、基于IHC的定量缺氧标志物（EF 5）与使用相同化合物（[18-F]-EF 5 PET）的非侵入性测定，并根据临床结果确定缺氧在人类神经胶质肿瘤中重要的机制和情况。

DESCRIPTION (provided by applicant): The effects of hypoxia on tumor physiology and response to radiation therapy have been extensively described using in vitro studies, pre-clinical models and in human tumors. Investigations regarding the modulation of molecular signaling by hypoxia are less advanced, with the conclusions of the majority of published studies performed in cellular or subcellular systems. Despite the observation of abnormal blood vessels and regions of pseudopalisading necrosis in high-grade glial brain tumors, little attention has been given to the role of hypoxia in the mechanism of their progression. Recently however, the central role of hypoxia in brain tumor progression and aggressiveness has been hypothesized based on pathological examination of WHO Grade 4 glial tumors by Brat et al. Their studies and conclusions were based upon HIF-1? staining in regions of pseudopalisading necrosis. We have developed the methodology to directly and more specifically measure hypoxia in tissue from all grades of human brain cancer using biopsy-based immunohistochemical (IHC) analysis of EF5 binding. The current application proposes to extend our biopsy-based analyses to PET studies of [F-18]-EF5 and compare patient outcome with [F-18]-EF5 data and IHC-based endpoints (Specific Aim 1). In our second Specific Aim, the tissues obtained from these patients, as well as tissues archived from patients previously treated with EF5 will be used to study the physiologic and molecular hypoxia-dependent mechanisms that result in tumor resistance or cellular hypoxia tolerance. Analyses using software for fluorescence images, developed in our lab, will be performed on frozen sections stained for EF5, PECAM/CD31 (blood vessels), TUNEL (apoptosis) and Ki67 (proliferation). In our third Specific Aim, tissue microarrays (TMAs) will be constructed to assess the impact of microenvironment on molecular signaling pathways. At the completion of this grant we will have compared a validated, quantitative IHC-based marker of hypoxia (EF5) to the non-invasive assay using the identical compound ([18-F]-EF5 PET) and determined the mechanisms and situations under which hypoxia is important in human glial tumors, based upon clinical outcome.