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）：该提案的总体目标是开发一种创新的毒物基因组学方法，用于定义细胞基因表达级联中的关键元素，这些元素在暴露于物理或化学试剂后赋予跨物种不同的影响。 由于传统的毒理基因组学方法无法可靠地解决跨物种毒性差异，并且主要依赖相关证据将转录变化与病理终点相关联，因此需要一种新的方法。 缺失的部分是对改变基因列表中包含的因果关系以及由此产生的毒理学结果的机械理解。 该研究的总体假设是，定义基因表达变化的级联网络对于理解化学品的毒性和预测其跨物种反应保守性至关重要。 这些变化包括初级、次级和三级基因表达反应之间的相互关系。 这一假设将使用独特的基因组工具组合进行测试，这些工具可以剖析接触典型肝毒剂苯巴比妥后的转录反应，苯巴比妥在啮齿类动物和人类中具有不同的致癌活性。 该提案的具体目标是：（1）通过使用全基因组微阵列进行时程基因表达研究，检验苯巴比妥将导致原代小鼠和人类肝细胞中基因表达暂时可分辨的变化的假设； (2) 检验以下假设：苯巴比妥的基因表达级联可以通过使用 RNA 干扰单独阻断在较早时间点诱导的关键调控基因并测量对基因表达下游变化的影响来描绘； (3)检验以下假设：与早期细胞增殖事件相关的特定次级基因表达反应存在于小鼠肝细胞中，但不存在于人肝细胞中。 通过确定次级转录反应和主要调控基因之间的相互关系，我们将能够从机制上将增殖子网络与负责跨物种差异的主要事件或受体联系起来。 通过这项研究，我们相信将开发出一种新的毒理学方法，可以比较不同物种之间的信号级联，以预测毒性反应的保守性，并为许多化学制剂的作用机制提供新的见解。