RAD-Induced Nitric Oxide & Cellular Radiosensitivity

RAD 诱导的一氧化氮

• 批准号: 6757956
• 负责人: ROSS B MIKKELSEN
• 金额: $ 26.74万
• 依托单位: VIRGINIA COMMONWEALTH UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-10 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6757956
• 关键词: CHO cells; MCF7 cell; biological signal transduction; biomimetics; cell growth regulation; cytoprotection; enzyme activity; enzyme induction /repression; free radical oxygen; gene targeting; genetically modified animals; green fluorescent proteins; ionizing radiation; laboratory mouse; mitogen activated protein kinase; nitric oxide; nitric oxide synthase; protein tyrosine phosphatase; radiation sensitivity; radiobiology; superoxide dismutase; tissue /cell culture; transfection; western blottings

DESCRIPTION (provided by applicant): Several recent studies have demonstrated that ionizing radiation activates a metabolic process resulting in the transient generation of reactive oxygen (ROS). The underlying mechanism for this amplification and signaling mechanism of cytoplasmic ionization events appears to involve a Ca2+ dependent signal propagated from one mitochondria to another within a cell. Temporally coincident is the activation of a constitutive, Ca2+ dependent nitric oxide synthase (NOS*). It is proposed that the radiation-induced activation of NOS is a mechanism that (1) limits the amount of cytotoxic, mutagenic ROS (02-/H202) formed after radiation; and (2) activates signal transduction pathways involved in cell growth regulation. Because of its unique physiochemical properties, the enhanced NO. generation after irradiation also provides a mechanism for the intracellular and intercellular propagation within a tissue of a signal generated by an ionization event that has occurred in a single cell. To test this proposal, there are two specific aims: Determine whether modulation of NOS activity by molecular and pharmacological means enhances radiation-induced cell killing and/or mutagenesis that in turn can be reduced by over expression of superoxide dismutase (SOD) or treating cells with SOD mimetics. Determine whether manipulation of NOS activity modulates radiation-induced ROS generation measured as 02 Test (a) whether manipulation of the NO-/sGC/PKG signal transduction pathway alters cellular radiosensitivity; (b) the relationships between radiation-stimulated sGC/PKG and downstream consequences including transcriptional activation of c-fos and p21 Waf1/Cip1 and activation of members of the MAPK family and (c) whether radiation-stimulated transient S-nitrosylation and inhibition of cytosolic and nuclear protein tyrosine phosphatases (PIP) are involved in cellular responses to radiation (SHP-2, SHP-1 and cdc25).

描述（由申请人提供）：最近的几项研究表明，电离辐射会激活代谢过程，导致活性氧（ROS）的瞬时产生。细胞质电离事件的这种放大和信号传导机制的潜在机制似乎涉及从细胞内的一个线粒体传播到另一个线粒体的 Ca2+ 依赖性信号。时间上同时发生的是组成型 Ca2+ 依赖性一氧化氮合酶 (NOS*) 的激活。有人提出，辐射诱导的NOS激活是一种机制：(1)限制辐射后形成的细胞毒性、致突变性ROS(02-/H2O2)的量； (2) 激活参与细胞生长调节的信号转导途径。由于其独特的理化性质，增强的NO。辐射后的产生还提供了由单个细胞中发生的电离事件产生的信号在组织内的细胞内和细胞间传播的机制。为了测试该提案，有两个具体目标： 确定通过分子和药理学手段调节 NOS 活性是否会增强辐射诱导的细胞杀伤和/或诱变，而这种杀伤和/或诱变又可以通过超氧化物歧化酶 (SOD) 的过度表达或用 SOD 模拟物处理细胞来减少。确定 NOS 活性的操作是否会调节辐射诱导的 ROS 生成（测量为 02） 测试（a）操作NO-/sGC/PKG信号转导通路是否改变细胞放射敏感性； (b) 辐射刺激的 sGC/PKG 与下游后果之间的关系，包括 c-fos 和 p21 Waf1/Cip1 的转录激活以及 MAPK 家族成员的激活，以及 (c) 辐射刺激的瞬时 S-亚硝基化和抑制是否胞浆和核蛋白酪氨酸磷酸酶 (PIP) 参与细胞对辐射的反应（SHP-2、SHP-1 和 cdc25）。