Oxidative Stress in Cr(VI)-induced Carcinogenesis

Cr(VI) 诱导的癌变过程中的氧化应激

• 批准号: 7213788
• 负责人: Xianglin Shi
• 金额: $ 27.84万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-07 至 2012-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7213788
• 关键词: Animals; Antioxidants; Biology; CDC42 gene; California; Cancer Etiology; Carcinogens; Cells; Chemical Structure; Chemicals; Consumption; DNA Damage; Detection; Development; Dominant-Negative Mutation; Early Diagnosis; Electron Spin Resonance Spectroscopy; Environmental Carcinogens; Environmental Exposure; Enzymes; Epithelial; Exposure to; Free Radicals; Frequencies; Generations; Goals; Human; Hydroxyl Radical; Incidence; Inhalation Exposure; International Agency for Research on Cancer; Intervention; JUN gene; Life; Link; Lipid Peroxidation; Lung; MAPK1 gene; Malignant neoplasm of lung; Medicine; Methods; Molecular; NADPH Oxidase; NF-kappa B; Nose; Nuclear; Nude Mice; Occupational; Occupational Groups; Oral; Organ; Oxidative Stress; Pathway interactions; Play; Post-Translational Protein Processing; Prevention strategy; Production; Reaction; Reactive Oxygen Species; Risk Assessment; Role; Signal Transduction; Spin Trapping; Stress; Superoxides; Techniques; Testing; Transcription Factor AP-1; Transgenic Mice; Water; cancer risk; carcinogenesis; carcinogenicity; cdc42 GTP-Binding Protein; cell injury; cell transformation; chromium hexavalent ion; free radical oxygen; in vivo; oxidation; response; transcription factor; tumorigenesis

DESCRIPTION (provided by applicant): Hexavalent chromium [Cr(VI)] is a known environmental carcinogen. Environmental exposure to Cr(VI)-containing compounds causes cancers of various organs. Its mechanism of carcinogenic actions remains to be investigated. Recent studies have demonstrated that reduction of Cr(VI) to its lower oxidation states is important for Cr(VI)-induced carcinogenesis. It has been shown that cellular reduction of Cr(VI) generates reactive oxygen species (ROS) which cause various cellular injuries. We hypothesize that Cr(VI) induces generation of ROS, which activate nuclear transcription factors, leading to cell transformation and tumorigenesis. In Specific Aim 1, we will identify ROS generated in Cr(VI) treated human lung bronchial epithelial (BEAS-2B) cells and the mechanism involved. We will emphysize the role of CDC42 signaling and the involvement of p47phox and NADPH oxidases in the molecular mechanism of Cr(VI)-induced ROS production. In Specific Aim 2, we will detect reactive Cr(V) intermediates produced in Cr(VI) reduction by living animals and identify the chemical structures of these intermediates. We will also detect and identify superoxide (O2'-) and hydroxyl ('OH) radicals produced by intact animals exposed to Cr(VI). Major methods to be used in this aim are low frequency electron spin resonance (ESR) spectroscopy and ESR spin trapping. In Specific Aim 3, we will investigate Cr(VI)-induced activation of NF-kappaB and AP-1 in BEAS-2B cells and in transgenic mice. We will use a dominant negative mutant MEK1/2, a dominant negative mutant ERK2, or a dominant negative mutant c-jun (TAM67), respectively, to investigate the role of the MEK1/2-ERKs-AP-1 pathway in Cr(VI)-induced cell transformation. We will also use a dominant negative mutant IkappaBa or a dominant negative mutant IKK?, respectively, to determine the role of the IKK?-lkappaBa-NF-kappaB pathway in Cr(VI)-induced cell transformation. The involvement of ROS in these pathways will be investigated using expressions of specific antioxidant enzymes. Tumorigenesis will be investigated by injecting the transformed cells into athymic nude mice. We anticipate that Cr(VI) causes activation of transcription factors 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.

描述（申请人提供）： 六价铬[Cr(VI)]是一种已知的环境致癌物质。环境中接触含六价铬的化合物会导致多种器官的癌症。其致癌作用机制仍有待研究。最近的研究表明，将 Cr(VI) 还原至较低氧化态对于 Cr(VI) 诱导的致癌作用非常重要。研究表明，细胞中 Cr(VI) 的还原会产生活性氧 (ROS)，从而导致各种细胞损伤。我们假设 Cr(VI) 诱导 ROS 的产生，从而激活核转录因子，导致细胞转化和肿瘤发生。在具体目标 1 中，我们将鉴定 Cr(VI) 处理的人肺支气管上皮 (BEAS-2B) 细胞中产生的 ROS 及其相关机制。我们将强调 CDC42 信号传导的作用以及 p47phox 和 NADPH 氧化酶在 Cr(VI) 诱导 ROS 产生的分子机制中的参与。在具体目标 2 中，我们将检测活体动物还原 Cr(VI) 时产生的反应性 Cr(V) 中间体，并鉴定这些中间体的化学结构。我们还将检测和识别暴露于 Cr(VI) 的完整动物产生的超氧化物 (O2'-) 和羟基 ('OH) 自由基。用于此目的的主要方法是低频电子自旋共振（ESR）光谱和ESR自旋捕获。在具体目标 3 中，我们将研究 BEAS-2B 细胞和转基因小鼠中 Cr(VI) 诱导的 NF-kappaB 和 AP-1 激活。我们将分别使用显性失活突变体 MEK1/2、显性失活突变体 ERK2 或显性失活突变体 c-jun (TAM67) 来研究 MEK1/2-ERKs-AP-1 通路在 Cr( VI)诱导细胞转化。我们还将分别使用显性失活突变体 IkappaBa 或显性失活突变体 IKK? 来确定 IKK?-lkappaBa-NF-kappaB 途径在 Cr(VI) 诱导的细胞转化中的作用。将使用特定抗氧化酶的表达来研究 ROS 在这些途径中的参与。通过将转化的细胞注射到无胸腺裸鼠中来研究肿瘤发生。我们预计 Cr(VI) 通过 ROS 反应引起转录因子的激活，从而导致细胞转化和肿瘤发生。我们试图将细胞转化和肿瘤发生与特定转录因子和特定活性氧联系起来。