权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Cdk-2 Independent role of cyclin E in Cell survival

Cdk-2 细胞周期蛋白 E 在细胞存活中的独立作用

基本信息

批准号：
7589611
负责人：
Alexandru Almasan
金额：
$ 32.53万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-12-23 至 2013-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7589611
关键词：
Affect Apoptosis Apoptotic Binding Biological Markers C-terminal Caspase Cell Cycle Cell Cycle Checkpoint Cell Cycle Progression Cell Cycle Regulation Cell Proliferation Cell Survival Cells Characteristics Chronic Lymphocytic Leukemia Cleaved cell Clinical Clinical Treatment Competitive Binding Cyclin E Cytosol DNA Damage DNA Double Strand Break DNA Repair DNA Repair Pathway DNA biosynthesis DNA-PKcs Data Ectopic Expression Epithelial Fibroblasts G22P1 gene Generations Genetic Models Genotoxic Stress Hematopoietic Hematopoietic Neoplasms Human Individual Investigation Ionizing radiation Knock-out Knowledge Ligase Lymphocyte Mammalian Cell Mediating Mitochondria Modeling Molecular Mutagens Nonhomologous DNA End Joining Nuclear Patients Phosphotransferases Play Process Proteasome Inhibition Proteasome Inhibitor Proteins Proteolysis Radiation Radiation Tolerance Radiation therapy Regulation Repair Complex Research Resistance Role Signal Transduction Site Small Interfering RNA Testing Therapeutic Tumor Cell Line Ubiquitination caspase-3 cell growth regulation chemotherapy cytochrome c established cell line human CCNE1 protein knock-down multicatalytic endopeptidase complex mutant neoplastic cell novel prevent public health relevance repaired response

项目摘要

DESCRIPTION (provided by applicant): Cyclin E1 (CycE) represents an essential regulator of the mammalian cell cycle and DNA replication. Our studies have recently uncovered its new role in the cell survival of hematopoietic tumor cells. We found that CycE is cleaved proteolytically during apoptosis induced by typical genotoxic agents such as ionizing radiation. This cleavage is dramatic as it affects most cellular CycE and is characteristic to all human tumor hematopoietic cells we have examined, both established cell lines or primary, freshly isolated from human patients. This cleavage is important for apoptosis as expression of a cleavage-resistant CycE mutant blocks this process. CycE cleavage generates p18CycE, which is unable to bind Cdk2 or other known interactors of CycE. Our hypothesis, supported by preliminary data, is that CycE function is mediated by its interaction with Ku70, which we have identified as a novel p18CycE-binding partner. By binding to Ku70, p18CycE1 displaces Bax, leading to its activation. Indeed, p18CycE genesis coincides with Bax activation and loss of mitochondrial functions and the ensuing apoptosis is dependent on both Bax and Ku70, since it is prevented in cells rendered deficient in these proteins by knockout or siRNA-mediated knock-down. As Ku70 is a critical component of the nonhomologous end joining (NHEJ) DNA repair, our preliminary data indicate that the CycE fragment also affects the response to DNA damage and its repair. We will determine the mechanism by which p18CycE regulates apoptosis and DNA repair, in addition to inactivating CycE function. These studies are focused on a molecule that is unique in regulating all three responses to genotoxic stress: cell cycle control, DNA repair, and apoptosis. Our objective is to understand the regulation of CycE and derivative p18CycE following genotoxic stress and their impact on cells with differential radiation sensitivity. We seek to determine: 1) how the Ku70 interaction with p18CycE regulates cell survival, 2) the regulation and role of p18CycE1, 3) the therapeutic potential of p18CycE1. These investigations will establish the contribution to apoptosis of CycE1 independent of Cdk2. Our studies will increase our understanding of the mechanism by which CycE may provide a molecular switch by coordinating key responses to genotoxic stress, that include cell cycle control, DNA repair, and apoptosis that govern the radio- or chemotherapy-induced signals in clinical therapy. PUBLIC HEALTH RELEVANCE: Conversion of CycE1 to p18CycE1 is unique as it impacts on all key responses to genotoxic stress: cell proliferation, apoptosis, and DNA repair. Moreover, CycE1 is not converted to p18CycE1 in lymphocytes from normal individuals or in human epithelial or fibroblast cells. These investigations of p18CycE1 function in the absence of its Cdk2-dependent cell cycle and DNA replication regulatory function will contribute to our understanding of the novel role it plays, through p18CycE1, in apoptosis and DNA repair. In addition, these studies provide a unique approach to uncover fundamental knowledge on the intimate connections, coordinate regulation, and a possible molecular switch regulating the response of hematopoietic cells to DNA-damaging therapeutics that involve cell cycle control, DNA repair, and apoptosis.

描述（由申请人提供）：细胞周期蛋白E1（CycE）是哺乳动物细胞周期和DNA复制的重要调节因子。我们的研究最近发现了它在造血肿瘤细胞的细胞存活中的新作用。我们发现，CycE裂解蛋白水解过程中诱导的典型的遗传毒性剂，如电离辐射的细胞凋亡。这种切割是戏剧性的，因为它影响大多数细胞CycE，并且是我们检查的所有人类肿瘤造血细胞的特征，无论是建立的细胞系还是从人类患者新鲜分离的原代细胞。这种切割对于细胞凋亡是重要的，因为抗切割CycE突变体的表达阻断了该过程。CycE裂解产生p18 CycE，其不能结合Cdk2或其他已知的CycE相互作用物。我们的假设，初步数据的支持，是CycE功能介导的Ku70，我们已经确定为一种新的p18CycE结合伙伴的相互作用。p18CycE1通过与Ku70结合，取代Bax，导致其活化。事实上，p18CycE的发生与Bax的激活和线粒体功能的丧失相一致，并且随后的细胞凋亡依赖于Bax和Ku70两者，因为在通过敲除或siRNA介导的敲低而使这些蛋白质缺陷的细胞中，细胞凋亡被阻止。由于Ku70是非同源末端连接（NHEJ）DNA修复的关键组分，我们的初步数据表明，CycE片段也影响对DNA损伤及其修复的反应。我们将确定p18CycE调节细胞凋亡和DNA修复的机制，除了灭活CycE功能。这些研究集中在一种分子上，这种分子在调节对遗传毒性应激的所有三种反应中是独特的：细胞周期控制，DNA修复和凋亡。我们的目的是了解基因毒性应激后CycE及其衍生物p18 CycE的调节及其对具有不同辐射敏感性的细胞的影响。我们力求确定：1）Ku70与p18CycE的相互作用如何调节细胞存活，2）p18CycE1的调节和作用，3）p18CycE1的治疗潜力。这些研究将确定CycE1独立于Cdk2对细胞凋亡的贡献。我们的研究将增加我们对CycE可能通过协调对遗传毒性应激的关键反应来提供分子开关的机制的理解，所述遗传毒性应激包括细胞周期控制、DNA修复和细胞凋亡，所述细胞凋亡在临床治疗中控制放射或化疗诱导的信号。公共卫生关系： CycE1向p18CycE1的转化是独特的，因为它影响对遗传毒性应激的所有关键反应：细胞增殖、凋亡和DNA修复。此外，CycE1在正常个体的淋巴细胞或人上皮细胞或成纤维细胞中不转化为p18CycE1。这些调查的p18CycE1功能的Cdk2依赖的细胞周期和DNA复制调控功能的情况下，将有助于我们了解它所扮演的新角色，通过p18CycE1，在细胞凋亡和DNA修复。此外，这些研究提供了一种独特的方法来揭示有关密切联系的基本知识，协调调节，以及调节造血细胞对涉及细胞周期控制，DNA修复和凋亡的DNA损伤治疗的反应的可能分子开关。