MECHANISM OF NF-KB ACTIVATION BY DNA DAMAGE

描述（改编自研究者摘要）：DNA损伤剂 是抗癌治疗的重要组成部分。这些代理人引发了许多 细胞反应，包括诱导细胞凋亡。最近的数据表明 NF-κ B转录因子的激活可能具有抗凋亡作用， 方面的影响.了解NF-κ B激活的机制可能会导致 通过减弱下游抗细胞凋亡增强肿瘤杀伤。但 特异性DNA损伤后NF-κ B活化的确切机制尚不清楚。 该建议集中于喜树碱激活NF-κ B的机制 CPT相关抗癌剂，其为拓扑异构酶（Topo）I抑制剂。 无活性的NF-κ B存在于细胞质中，其活化需要 核转位核DNA如何激活细胞质NF-κ B 损害？这个实验室的研究强烈表明 细胞质信号通路。提出了三个具体目标，以测试 Topo-I在细胞核中产生DNA双链断裂的假设 启动最终激活IkappaB激酶的信号通路， 从其抑制剂IkappaB释放NF-κ B。两个目标将具体说明核 通过关注DSB的作用，研究CPT治疗引发的信号传导事件（Aim I）和DNA依赖性蛋白激酶（DNA-PK，Aim 2）。细胞周期表达 NF-κ B应答报告基因和限制性内切酶介导的 DSB将确定DSB是否足以激活NF-κ B。的 通过测定NF-κ B，将发现DNA-PK的关键参与， 活性在来自缺乏每种基因的小鼠的遗传匹配细胞中 激酶复合物组分。最后， 细胞质将通过关注CPT依赖的调节来指定， IkappaB激酶复合物，磷酸化抑制剂IkappaB，最终 释放活性NF-κ B（目的3）。目的我将确定目标特异性 Topo-I介导的DNA损伤引发NF-κ B活化。

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.