MECHANISM OF NF-KB ACTIVATION BY DNA DAMAGE

描述(改编自《调查者摘要》)：DNA损伤剂 是抗癌治疗的重要组成部分。这些代理人引来了无数 细胞反应，包括诱导细胞凋亡。最近的数据表明 核因子-kappaB转录因子的激活可能具有抗细胞凋亡作用 效果。了解核因子-kappaB的激活机制可能会导致 通过减弱下游的抗细胞凋亡药物来提高肿瘤杀伤率。然而， 核因子-kappaB在特定DNA损伤后被激活的确切机制尚不清楚。 本研究的重点是喜树碱激活核因子-kappaB的机制 (CPT相关抗癌药，即拓扑异构酶(TOPO)I抑制剂。 失活的核因子-kappaB存在于细胞质中，它的激活需要 核移位。胞质核因子-kappaB是如何被核DNA激活的 损坏？这个实验室的研究有力地表明了核子的存在 到细胞质信号转导途径。提出了三个具体的目标来测试 TOPO-I在细胞核中产生DNA双链断裂的假说 启动一条最终激活IkappaB激酶的信号通路 从其抑制剂IkappaB释放核因子-kappaB。两个目标将具体说明核 通过关注DSB的作用，通过CPT处理触发的信号事件(AIM I)和DNA依赖蛋白激酶(DNA-PK，Aim 2)。细胞周期蛋白的表达 一种核因子-kappaB应答报告和限制性内切酶介导的 DSB将决定DSB是否足以激活核因子-kappaB。这个 通过检测核因子-kappaB将揭示DNA-PK的关键参与 每种基因缺陷小鼠的基因匹配细胞的活性 激活剂复合体成分。最后，中的信令终点 细胞质将通过关注CPT依赖的调节来指定 IkappaB激酶复合体，使抑制剂IkappaB磷酸化，最终 释放活性的核因子-kappaB(目标3)。Aim I将确定靶点特异性 TOPO-I介导的DNA损伤触发核因子-kappaB的激活。

DESCRIPTION (As Adapted From the Investigator's Abstract): DNA damaging agents are an important component of anti-cancer therapy. These agents elicit numerous cellular responses, including the induction of apoptosis. Recent data suggest that the NF-kappaB transcription factor activation may have anti-apoptotic effects. Understanding the mechanisms of NF-kappaB activation may lead to improved tumor killing by attenuating downstream antiapoptotic. However, the exact mechanism of NF-kappaB activation after specific DNA damage is unknown. This proposal focuses on the mechanisms of NF-kappaB activation by camptothecin (CPT-related anticancer agents, which are Topoisomerase (Topo) I inhibitors. Inactive NF-kappaB is present in the cytoplasm and its activation requires nuclear translocation. How is cytoplasmic NF-kappaB activated by nuclear DNA damage? Studies in this laboratory strongly suggest the presence of a nuclear to cytoplasmic signaling pathway. Three Specific Aims are proposed to test the hypothesis that Topo-I generated DNA double-stranded breaks in the nucleus initiate a signaling pathway that ultimately activates IkappaB kinase to release NF-kappaB from its inhibitor IkappaB. Two aims will specify the nuclear signaling events triggered by CPT treatment by focusing on the role of DSB (Aim I) and DNA-dependent protein kinase (DNA-PK, Aim 2). Cell cycle expression of an NF-kappaB-responsive reporter and restriction enzyme mediated generation of DSB will determine whether DSB is sufficient for NF-kappaB activation. The critical involvement of DNA-PK will be uncovered by assaying the NF-kappaB activity in genetically matched cells from mice deficient for each of the kinase complex components. Finally the endpoint of the signaling in the cytoplasm will be specified by focusing on the CPT-dependent regulation of an IkappaB kinase complex that phosphorylates the inhibitor IkappaB to ultimately release active NF-kappaB (Aim 3). Aim I will determine the target specificity of Topo-I-mediated DNA damage to trigger NF-kappaB activation.