Reactive oxygen species in Ni(II) carcinogenesis

含镍化合物是人类致癌物质。它们的机制 致癌作用仍有待研究。最近的研究表明， 活性氧(ROS)可能起着重要作用。我们假设镍 诱导产生ROS，激活核转录因子，导致细胞 转化和肿瘤发生。特定目标1将检测和识别生成的RO 人支气管上皮细胞(BEAS-2B)和小鼠胚胎成纤维细胞 暴露在镍化合物中，并调查其中的机制。我们假设 镍(Ni3S2和NiCl2)能刺激细胞激活NADPH氧化酶 Cdc42和p47Phox产生超氧自由基，然后转化为氢 过氧化氢和羟基自由基。《特定目标2》将检验ROS是 NFAT和NFkappaB在细胞和体内对镍的反应所需的激活 化合物。ROS在镍诱导的NFAT和NFkappaB激活中的作用 将NFkappaB-荧光素酶或NFAT-荧光素酶共转染细胞进行鉴定 报告质粒和特定的ROS清除酶。用于体内研究，BALB/c 抗氧化酶或NADPH氧化酶(ROS)交替的转基因小鼠 产生酶)将被采用。具体目标3将调查ROS的作用， NFAT和NFkappaB在镍诱导的细胞转化和肿瘤发生中的作用我们 假设ROS激活转录因子并导致细胞转化和 肿瘤发生学。我们将使用dN-NFAT、dN-IkappaBalpha和dN-的过度表达 IKKbeta将调查NFAT和NFkappaB在镍细胞中的参与 转化和诱导肿瘤发生。ROS的作用将通过以下方式进行调查 特异性抗氧化酶的表达和NADPH氧化酶的变化。我们期待着 镍通过ROS反应引起NFAT和NFkappaB的激活，导致 细胞转化和肿瘤发生。我们尝试将细胞转化和 肿瘤的发生与特定的转录因子和特定的活性氧有关。 从这项建议中获得的结果将阐明ROS和 NFAT/NFkappaB信号通路在镍化合物致癌中的作用从长远来看 目标是提供关于以下机制的基本理解 镍的致癌作用；以满足对癌症风险机制信息的需求 评估暴露；提出早期发现的方法；并制定 干预和预防策略。含镍化合物是人类致癌物质。该项目将调查 从镍致癌假说看镍致癌的机制 激活核转录因子的ROS的产生，导致细胞 转化和肿瘤发生。我们的长期目标是理解 镍的致癌机制；提出早期检测方法；并开发 干预和预防策略。

Nickel-containing compounds are human carcinogens. The mechanisms of their carcinogenic actions remain to be investigated. Recent studies have indicated that reactive oxygen species (ROS) may play an important role. We hypothesize that nickel induces generation of ROS, which activate nuclear transcription factors, leading to cell transformation and tumorigenesis. Specific Aim 1 will detect and identify ROS generated in human bronchial epithelial cells (BEAS-2B) and mouse embryo fibroblast cells exposed to nickel compounds and investigate the mechanism involved. We hypothesize that nickel (Ni3S2 and NiCl2) can stimulate the cells to activate NADPH oxidase via cdc42 and p47phox to produce superoxide radical, which is then converted to hydrogen peroxide and hydroxyl radical. Specific Aim 2 will test the hypothesis that ROS are required for activation of NFAT and NFkappaB in cells and in vivo in response to nickel compounds. The role of ROS in nickel-induced activation of NFAT and NFkappaB in cells will be evaluated by co-transfection of NFkappaB-luciferase or NFAT-luciferase reporter plasmids and specific ROS scavenger enzymes. For in vivo study, BALB/c transgenic mice with alternation of antioxidant enzymes or NADPH oxidase (ROS generating enzyme) will be employed. Specific Aim 3 will Investigate the role of ROS, NFAT and NFkappaB in nickel-induced cell transformation and tumorigenesis. We hypothesize that ROS activate transcription factors and cause cell transformation and tumorigenesis. We will use overexpression of DN-NFAT, DN-IkappaBalpha and DN- IKKbeta to investigate the involvement of NFAT and NFkappaB in nickel-cell transformation and induced tumorigenesis. The role of ROS will be investigated using specific antioxidant enzyme expressions and NADPH oxidase alternation. We anticipate that nickel causes activation of NFAT and NFkappaB through ROS reactions, leading to cell transformation and tumorigenesis. We attempt to link the cell transformation and tumorigenesis with specific transcription factors and specific reactive oxygen species. The results obtained from this proposal will elucidate the role of ROS and NFAT/NFkappaB signaling in Ni compounds-induced carcinogenesis. The long term goals are to provide a fundamental understanding concerning the mechanism of carcinogenic actions of Ni; to fill a need for the mechanistic information of cancer risk assessment for exposure; to propose methods for early detection; and to develop intervention and prevention strategies. Nickel-containing compounds are human carcinogens. This project will investigate the mechanism of Ni-induced carcinogenesis by testing the hypothesis that nickel induces generation of ROS, which activate nuclear transcription factors, leading to cell transformation and tumorigenesis. The long term goals are to understand the mechanism of Ni-carcinogenesis; to propose methods for early detection; and to develop intervention and prevention strategies.