Survival Signaling After Genotoxic Insult

基因毒性侮辱后的生存信号

• 批准号: 7545032
• 负责人: SUSAN M CERYAK
• 金额: $ 5.43万
• 依托单位: GEORGE WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7545032
• 关键词: Address; Alleles; Apoptosis; Apoptotic; BAD gene; Bad protein; 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; Condition; Cyclins; DNA Adduction; DNA Adducts; DNA Damage; DNA biosynthesis; DNA chemical synthesis; 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 Activation; 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; Range; Regulation; Resistance; Risk Factors; Role; S-Phase Fraction; Signal Pathway; Signal Transduction; Small Interfering RNA; Source; Survivors; TP53 gene; Telomerase; Testing; Thinking; 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

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.

在基因毒性损伤后，控制细胞存活的关键信号的不适当激活/失活可能导致 自主生长和肿瘤性转化。基因毒性损伤的最初后果是细胞周期 检查点阻断，但遗传毒性也可能激活细胞死亡途径，即细胞凋亡或终末生长停滞。 细胞对基因毒性伤害的生存反应可能产生内在的死亡抵抗；这样的选择性生长 优势可能允许出现转化的表型。某些形式的六价铬[(六价铬)] 是已知的人类呼吸道致癌物质，可用作有用的遗传毒性工具 毒物学上的重要性。我们的初步研究表明，蛋白质酪氨酸的维持 与AKT激活一致的磷酸化，推翻了铬诱导的生长停滞和 增强克隆人的存活率。已知AKT的结构性激活在肿瘤的发生中起重要作用。 因此，这一提议的总体目标是阐明调节细胞的协调信号事件 遗传毒性侮辱后的命运决定和生存。拟议中的两个首要假设 研究表明：1)在铬(Vl)基因毒性后，AKT的激活改变了细胞命运的平衡，趋向于存活 2)面对铬(Vl)基因毒性的侮辱，AKT的激活增加了基因组的不稳定性。为了测试 这些假说，我们将运用分子、药理学和遗传学的方法，通过使用相关的模型 人二倍体肺成纤维细胞(HLF)和人大气道上皮细胞(HLAE)体系的建立及相关研究 AKT通路的关键信号成分的参与。AKT效应的分子电路将 在目标1中描述，以及AKT诱导的对由基因毒素引起的 目标2将研究细胞死亡的程序。目标3将确定AKT在抗性中的作用 铬(Vl)诱导对铬离子获得性耐药细胞亚克隆群体的克隆性致死作用 诱导的克隆性死亡。我们将使用与人类有关的浓度范围内的可溶性Na2CrO4 暴露，其DNA加合物频率和遗传毒性损害已有很好的记录。评选结果 拟议的研究将确定赋予细胞生长优势的分子机制(S) 遗传毒性侮辱，为理解铬(Vl)诱导的肺癌提供了新的见解，而 解决对敏感和特定的分子指数的需求，这些指数可以与暴露于 致癌物以及它们的癌症发病率。分子电路的勾画 参与AKT生存信号可能还有一个额外的好处，即识别Rational的分子靶点 抗癌治疗中的药物设计。