Cellular Redox Control and Oxidant Signaling

细胞氧化还原控制和氧化信号传导

• 批准号: 7031039
• 负责人: A RICHARD WHORTON
• 金额: $ 26.32万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031039
• 关键词: NAD(P)H dehydrogenase; apoptosis; biological signal transduction; cell growth regulation; cell proliferation; enzyme activity; fibroblasts; focal adhesion kinase; free radical oxygen; gene expression; genetic regulation; growth factor receptors; hydrogen peroxide; isozymes; mitogen activated protein kinase; neoplastic cell culture for noncancer research; nitric oxide; oxidation reduction reaction; phosphatidylinositol 3 kinase; protein structure function; tissue /cell culture; transfection

DESCRIPTION (provided by applicant): Partially reduced oxygen species are reactive derivatives of molecular oxygen well characterized to participate in cellular responses generally classified as oxidative stress. While the focus in the past has been on the role of reactive oxygen species (ROS) in toxicity and disease mechanisms, it has become increasingly clear that these molecules are powerful signaling molecules employed in normal cell growth and survival. The outcome of exposure/production of ROS depends on concentration and time course such that high, bolus exposure leads to toxicity (apoptosis or necrosis) while low continuous exposure enhances cell survival and stimulates growth. Recently several lines of evidence suggest that ROS produced by NAD(P)H oxidases (NOX) function in initiation and regulation of cell signaling pathways. For example, a NOX isoform appears to be activated by receptor tyrosine kinases (EGFR, PDGF, IR) leading to H202 production and increased phosphorylation of the receptor and enhanced signaling, inhibition of NOX activity in melanoma cells by antisense to NOX4 or p22phox leads to growth inhibition, and expression of NOX1 in fibroblasts leads to a transformed phenotype and tumor formation when these cells are injected in a mouse model. Further, elevated NOX expression is associated with smooth muscle cell proliferation and commonly seen in cells derived from human cancers. The mechanism through which NOX isoforms regulate growth and survival are not known. However, studies with exogenously applied H202 would suggest activation of growth and survival (antiapoptotic) signals are important. Thus, in these studies we will test the hypothesis that cellular expression of NOX isoforms regulates growth factor receptor activity and provides antiapoptotic signals leading to cell growth and survival. To accomplish this, we will manipulate NOX levels in cells in culture and determine the effects of altered expression on growth and apoptosis and investigate the underlying cellular mechanisms.

描述(由申请人提供)：部分还原的氧物种是分子氧的活性衍生物，其特征是参与细胞反应，通常被归类为氧化应激。虽然过去的焦点一直集中在活性氧物种(ROS)在毒性和疾病机制中的作用上，但越来越清楚的是，这些分子是用于正常细胞生长和生存的强大信号分子。暴露/产生ROS的结果取决于浓度和时间过程，因此高剂量的剂量暴露会导致毒性(细胞凋亡或坏死)，而低剂量的持续暴露会增强细胞的存活和刺激生长。最近一些证据表明，由NAD(P)H氧化酶(NOX)产生的ROS在细胞信号通路的启动和调节中发挥作用。例如，NOX亚型似乎被受体酪氨酸激酶(EGFR，PDGF，IR)激活，导致H202产生，受体磷酸化增加和信号增强，NOX活性通过反义NOX4或p22Phox抑制黑色素瘤细胞的活性导致生长抑制，以及NOX1在成纤维细胞中的表达导致表型转化和肿瘤形成。此外，NOX表达升高与平滑肌细胞增殖有关，通常见于人类癌症来源的细胞。NOX亚型调节生长和生存的机制尚不清楚。然而，对外源性应用H202的研究表明，激活生长和生存(抗凋亡)信号是重要的。因此，在这些研究中，我们将检验这一假设，即NOX亚型的细胞表达调节生长因子受体的活性，并提供导致细胞生长和存活的抗凋亡信号。为了实现这一点，我们将操纵培养细胞中的NOX水平，并确定表达变化对生长和细胞凋亡的影响，并探讨其潜在的细胞机制。