Survival Signaling After Genotoxic Insult

基因毒性侮辱后的生存信号

基本信息

批准号：
7746024
负责人：
SUSAN M CERYAK
金额：
$ 3.31万
依托单位：
GEORGE WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-01-01 至 2010-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7746024
关键词：
Address Alleles Apoptosis Apoptotic Biological Biological Assay Biological Markers Biological Models Bypass Carcinogens Cell Cycle Cell Cycle Arrest Cell Cycle Checkpoint Cell Cycle Progression Cell Death Cell Proliferation Cell Survival Cells Cessation of life Chemicals Chromosomes Complex Cyclins DNA Adduction DNA Adducts DNA Damage DNA biosynthesis Data Diploidy Dominant-Negative Mutation Drug Design Early Diagnosis Environmental and Occupational Exposure Equilibrium Event Evolution Exposure to Face Fibroblasts Foundations Frequencies G2/M Checkpoint Pathway Gene Proteins Gene Silencing Genes Genetic Genomic Instability Genotoxic Stress Growth Human In Situ Incidence Injury Kinetics Lead Lesion Litigation Lung Maintenance Malignant Neoplasms Mediating Methods Mitotic Molecular Molecular Target Mutagenesis Mutagens Mutation Neoplastic Cell Transformation Pathway interactions Phenotype Phosphorylation Phosphotransferases Physiological Play Population Post-Translational Protein Processing Protein Tyrosine Kinase Protein Tyrosine Phosphatase Protein-Serine-Threonine Kinases Proteins Proto-Oncogene Proteins c-akt Public Health Regulation Resistance Risk Factors Role S-Phase Fraction Signal Pathway Signal Transduction Small Interfering RNA Source Survivors TP53 gene Telomerase Testing Tyrosine Phosphorylation Up-Regulation base cancer therapy carcinogenesis cell growth chromium hexavalent ion exposed human population genotoxicity human large airway epithelial cell indexing inhibitor/antagonist insight lung carcinogenesis neoplastic programs protein expression resistance mechanism respiratory response tool tumor progression uptake

项目摘要

Inappropriate activation/inactivation of key signals that control cell survival after genotoxic insult can contribute to autonomous growth and neoplastic transformation. An initial consequence of genotoxic injury is cell cycle checkpoint arrest but genotoxicity may also activate cell death pathways of apoptosis or terminal growth arrest. Cellular survival responses to genotoxic insult may produce intrinsic death-resistance; such a selective growth advantage may allow for emergence of a transformed phenotype. Certain forms of hexavalent chromium [(Cr(VI)] are known human respiratory carcinogens that can be employed as useful genotoxic tools with relevant toxicological importance. Our preliminary studies suggest that maintenance of protein tyrosine phosphorylation, which is coincident with AKT activation, overrides Cr-induced growth arrest and enhances clonogenic survival. Constitutive AKT activation is known to play an important role in carcinogenesis. Therefore, the overall objective of this proposal is to elucidate the coordinate signaling events that mediate cell fate determination and survival after genotoxic insult. The dual overarching hypotheses of the proposed studies are that: 1) AKT activation shifts the balance of cell fates, toward survival, after Cr(Vl) genotoxic insult; and 2) AKT activation in the face of Cr(Vl) genotoxic insult increases genomic instability. To test these hypotheses, we will employ molecular, pharmacological and genetic approaches, by using relevant model systems of human diploid lung fibroblasts (HLF), and human large airway epithelial cells (HLAE) and studying the involvement of key signaling components of the AKT pathway. The molecular circuitry of the AKT effect will be delineated in Aim 1, and the consequences of an AKT-induced "override" of the genotoxin-elicited program of cell death will be investigated in Aim 2. Aim 3 will identify the role of AKT in resistance to Cr(Vl)-induced clonogenic lethality in a subclonal population of cells with acquired resistance to Cr- induced clonogenic death. We will use soluble Na2CrO4 at a range of concentrations relevant to human exposure, and for which the DNA adduct frequencies and genotoxic lesions are well documented. Results of the proposed studies will identify molecular mechanism(s) that confer a growth advantage to cells after genotoxic insult, and add new insights to the understanding of Cr(Vl)-induced lung carcinogenesis, while addressing a need for sensitive and specific molecular indices that can be correlated with exposure to carcinogenic agents, as well as with their cancer incidence. Delineation of the molecular circuitry involved in AKT survival signaling may have the added benefit of identifying molecular targets for rational drug design in anti-cancer therapy.

基因毒性损伤后控制细胞存活的关键信号的不适当激活/失活可能会导致自主生长和肿瘤转化。基因毒性损伤的最初后果是细胞周期检查点停滞，但基因毒性也可能激活细胞凋亡或终末生长停滞的细胞死亡途径。细胞对基因毒性损伤的生存反应可能会产生内在的死亡抵抗力；这样的选择性增长优势可能会导致转化表型的出现。某些形式的六价铬 [(Cr(VI)] 是已知的人类呼吸道致癌物，可用作有用的遗传毒性工具毒理学重要性。我们的初步研究表明，维持蛋白质酪氨酸磷酸化与 AKT 激活同时发生，可克服 Cr 诱导的生长停滞，提高克隆存活率。众所周知，AKT 的组成型激活在致癌过程中发挥着重要作用。因此，该提案的总体目标是阐明介导细胞的协调信号传导事件基因毒性损伤后的命运决定和生存。所提出的双重总体假设研究表明：1) Cr(VI) 基因毒性后，AKT 激活会改变细胞命运的平衡，走向生存侮辱; 2) 面对 Cr(VI) 基因毒性损伤时 AKT 激活会增加基因组不稳定性。测试这些假设，我们将采用分子、药理学和遗传学方法，通过使用相关模型人二倍体肺成纤维细胞（HLF）和人大气道上皮细胞（HLAE）系统并研究 AKT 通路的关键信号传导成分的参与。 AKT 效应的分子电路将目标 1 中描述了 AKT 诱导的基因毒素“覆盖”的后果目标 2 将研究细胞死亡程序。目标 3 将确定 AKT 在耐药性中的作用 Cr(VI) 在获得 Cr- 抗性的细胞亚克隆群体中诱导克隆致死诱导克隆性死亡。我们将使用与人体相关的一系列浓度的可溶性 Na2CrO4 暴露，并且 DNA 加合物频率和基因毒性损伤都有详细记录。结果拟议的研究将确定赋予细胞生长优势的分子机制基因毒性损伤，并为理解 Cr(VI) 诱导的肺癌发生增添新的见解，同时满足对与暴露相关的敏感和特定分子指数的需求致癌物质，以及它们的癌症发病率。分子电路的描绘参与 AKT 生存信号传导可能具有识别合理分子靶标的额外好处抗癌治疗中的药物设计。