Microenvironment: Imaging/Implications in Brain Tumors

描述（由申请人提供）：缺氧对肿瘤生理和放射治疗反应的影响已经通过体外研究、临床前模型和人类肿瘤进行了广泛的描述。关于缺氧对分子信号的调节的研究还不太深入，大多数已发表的研究结论都是在细胞或亚细胞系统中进行的。尽管在高级别神经胶质性脑肿瘤中观察到血管异常和假性乳样坏死区域，但缺氧在其进展机制中的作用却很少受到关注。然而，最近，Brat等人基于WHO 4级神经胶质肿瘤的病理检查，假设了缺氧在脑肿瘤进展和侵袭性中的核心作用。他们的研究和结论是基于HIF-1？假性乳样坏死区域的染色。我们已经开发了一种方法，通过基于活检的免疫组织化学（IHC）分析EF5结合，直接和更具体地测量所有级别的人类脑癌组织中的缺氧。目前的申请建议将我们基于活检的分析扩展到[F-18]-EF5的PET研究，并将患者结果与[F-18]-EF5数据和基于ihc的终点进行比较（Specific Aim 1）。在我们的第二个特异性目标中，从这些患者获得的组织，以及之前接受过EF5治疗的患者的组织，将用于研究导致肿瘤抵抗或细胞缺氧耐受的生理和分子缺氧依赖机制。使用我们实验室开发的荧光图像软件，将对EF5、PECAM/CD31（血管）、TUNEL（细胞凋亡）和Ki67（增殖）染色的冷冻切片进行分析。在我们的第三个特定目标中，将构建组织微阵列（tma）来评估微环境对分子信号通路的影响。在这项资助完成后，我们将比较一种有效的、定量的基于免疫组化细胞的缺氧标志物（EF5）和使用相同化合物（[18-F]-EF5 PET）的无创检测，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.