Comparative genomics of species-specific tumor promotion

物种特异性肿瘤促进的比较基因组学

• 批准号: 6998902
• 负责人: Russell S Thomas
• 金额: $ 24.83万
• 依托单位: THE HAMNER INSTITUTES
• 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 2007-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6998902
• 关键词: RNA interference; animal genetic material tag; biological signal transduction; cell growth regulation; cell proliferation; functional /structural genomics; gene expression profiling; genetic models; genetic regulation; genetic transcription; hepatotoxin; human genetic material tag; human tissue; laboratory mouse; microarray technology; model design /development; molecular biology information system; pharmacogenetics; phenobarbital; species difference; tissue /cell culture; toxicology

DESCRIPTION (provided by applicant): The overall objective of this proposal is to develop an innovative toxicogenomics approach for defining critical elements in cellular gene expression cascades that confer differential effects across species following exposure to physical or chemical agents. A new approach is required since traditional toxicogenomic methods have not reliably addressed cross-species differences in toxicity and have primary relied on correlative evidence to associate transcriptional changes with a pathological end point. The missing component is a mechanistic understanding of the cause-and-effect relationships contained within the lists of altered genes and the resulting toxicological outcome. The overarching hypothesis for the proposed research is that defining the cascading network of gene expression changes is essential for understanding the toxicity of chemicals and predicting their cross-species conservation of response. These changes include the interrelationships between the primary, secondary, and tertiary gene expression responses. This hypothesis will be tested using unique combination of genomic tools that can dissect these transcriptional responses following exposure to a prototypical hepatotoxicant, phenobarbital that has different carcinogenic activity in rodents and humans. The specific aims of this proposal are: (1) test the hypothesis that phenobarbital will cause temporally resolvable changes in gene expression in primary mouse and human hepatocytes through time-course gene expression studies using whole-genome microarrays; (2) test the hypothesis that the gene expression cascade for phenobarbital can be delineated by individually blocking key regulatory genes induced at earlier time points using RNA interference and measuring the effect on down-stream changes in gene expression; (3) test the hypothesis that specific secondary gene expression responses related to early cell proliferation events exist in mouse hepatocytes, but not in human hepatocytes. By determining the interrelationships between the secondary transcriptional responses and the primary regulatory genes, we will be able to mechanistically link the proliferative subnetwork to the primary event or receptor responsible for cross-species differences. Through this study we believe a novel approach to toxicology will be developed that allows comparisons of the signaling cascades across species to predict the conservation of the toxic response as well as provide new insights into the mechanism of action for many chemical agents.

描述（由申请人提供）：该提案的总体目的是开发一种创新的毒物学方法，以定义细胞基因表达级联的关键元素，该方法在暴露于物理或化学药物后赋予跨物种的差异效应。 需要一种新的方法，因为传统的毒性方法没有可靠地解决毒性的跨物种差异，并且主要依靠相关证据将转录变化与病理终点相关联。 缺失的组成部分是对改变基因列表中包含的因果关系的机械理解和由此产生的毒理学结果。 提出的研究的总体假设是，定义基因表达变化的级联网络对于理解化学物质的毒性和预测其跨物种的响应保护至关重要。 这些变化包括主要，次级和三级基因表达反应之间的相互关系。 该假设将使用基因组工具的独特组合进行检验，这些工具可以在暴露于典型的肝毒性，苯巴比妥之后剖析这些转录反应，在啮齿动物和人类中具有不同的致癌活性。 该提案的具体目的是：（1）检验以下假设：苯巴比妥将在原代小鼠和人肝细胞中通过使用全基因组微阵列的时间谱系基因表达研究引起基因表达的时间分解变化； （2）检验以下假设：可以通过使用RNA干扰在早期的时间点诱导的关键调节基因并测量基因表达的下游变化的影响来描述苯巴比妥基因表达级联。 （3）检验以下假设：小鼠肝细胞中存在与早期细胞增殖事件有关的特定二级基因表达反应，但在人肝细胞中不存在。 通过确定次级转录响应与主要调节基因之间的相互关系，我们将能够将增殖性子网络与主要事件或负责跨物种差异的受体联系起来。 通过这项研究，我们认为将开发出一种新的毒理学方法，可以比较跨物种的信号级联反应，以预测毒性反应的保护，并为许多化学剂的作用机理提供新的见解。