Cellular Redox Control and Oxidant Signaling

细胞氧化还原控制和氧化信号传导

• 批准号: 6778412
• 负责人: A RICHARD WHORTON
• 金额: $ 29.99万
• 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/6778412
• 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）：部分减少的氧物质是分子氧的反应性衍生物，其特征是参与通常归类为氧化应激的细胞反应。尽管过去的重点一直是活性氧（ROS）在毒性和疾病机制中的作用，但越来越明显的是，这些分子是在正常细胞生长和生存中使用的强大信号分子。 ROS暴露/产生的结果取决于浓度和时间过程，因此，高注球暴露会导致毒性（凋亡或坏死），而低连续暴露则可以增强细胞存活并刺激生长。最近，几种证据表明，NAD（P）H氧化酶（NOX）功能在细胞信号通路的起始和调节中产生的ROS。例如，似乎通过受体酪氨酸激酶（EGFR，PDGF，IR）激活了NOX同工型，从而导致H202产生并增加受体的磷酸化并增强信号传导，通过对NOX4或P22Phox的抗义导致NOX细胞中NOX活性的抑制当将这些细胞注入小鼠模型中时，成纤维细胞中NOX1的表达会导致转化的表型和肿瘤形成。此外，升高的NOX表达与平滑肌细胞增殖有关，并且通常在人类癌症的细胞中看到。 NOX同工型调节生长和存活的机制尚不清楚。但是，外源应用H202的研究表明生长和生存（抗凋亡）信号的激活很重要。因此，在这些研究中，我们将检验以下假设：NOX同工型的细胞表达调节生长因子受体活性，并提供抗凋亡信号，从而导致细胞生长和存活。为此，我们将操纵培养细胞中的NOX水平，并确定表达改变对生长和凋亡的影响，并研究潜在的细胞机制。