Mitochondrial Metabolic Reprogramming and DNA Damage in Arsenic Carcinogenesis

 描述(由申请人提供)：虽然流行病学研究已将砷暴露与肺癌风险增加联系在一起，但亚砷酸盐暴露导致肺癌发生的分子机制仍不明确。最近的文献表明，线粒体(MT)代谢改变、氧化应激和DNA损伤在环境中是致癌的，但这些过程及其相互作用背后的生化失调尚不清楚。同样不清楚的是，在模型系统中对AS致癌的台面理解是否可以转化为对人类癌症的床边理解。在这份R21/R33提案中，这组研究人员将通过采用一种综合的组学方法来解决这些问题，该方法使用稳定同位素分辨代谢组学(SIRM)来定义线粒体和细胞代谢网络，这些网络对肺细胞的增殖、氧化还原动态平衡和氧化DNA损伤/修复反应至关重要，受到AS转化和致癌的干扰。这种方法将通过查询基因组、表观基因组和转录测序数据，在基因突变、表观遗传和转录水平上揭示途径变化，以进一步测试它们的失调(如关键酶和相关调节蛋白)。研究人员将在R21阶段实现他们的目标(SA1和2)，然后在R33阶段实现SA3和4，并使用SIRM确定AS转化的肺细胞中线粒体和细胞代谢网络是否以及如何改变。转化的肺细胞将在体外和小鼠异种移植中使用SIRM进行研究。获得的重新编程的代谢网络将与从人类肺癌患者体内单独获得的代谢网络相关。SA2)将ROS的产生、线粒体和核DNA损伤/修复过程与AS转化的肺细胞中的代谢重新编程联系起来。SA1和SA2数据的关联将为进一步检验SA3和SA4的因果关系提供假设。SA3)通过时间依赖关系揭示AS诱导转化过程中改变的线粒体/细胞代谢网络、ROS产生和DNA损伤之间的因果关系。SA4)定位AS转化的肺细胞中相应的遗传、表观遗传学和基因表达的变化，以用于AS作用的假说检验。下一代序列数据将被获取和查询，以获得突变特征、表观遗传状态以及参与重新编程的代谢网络、氧化还原平衡和DNA修复的关键基因的mRNA表达。这些数据将有助于描绘AS诱导的遗传或表观遗传损伤如何导致代谢重新编程，反之亦然。在模拟肺细胞系统中，对AS作用的基因组、表观基因组、转录和代谢组学分析的这种整合，将为了解线粒体中的代谢失调和DNA损伤以及它们可能如何与核DNA损伤和基因表达变化有关提供前所未有的详细见解。综合的组学信息将有助于对AS诱导的分子机制进行全面的验证研究 由砷暴露引起的对人类肺癌的这些基本见解的致癌和翻译(例如，发现机械和强大的生物标记物模式)。

 DESCRIPTION (provided by applicant): Although epidemiological studies have associated arsenic (As) exposures with increased risk of lung cancer, the molecular mechanisms involved in lung cancer development by arsenite exposure remain poorly defined. Recent literature has implicated altered mitochondrial (mt) metabolism, oxidative stress, and DNA damage in environmental As carcinogenesis, but the biochemical dysregulations that underlie these processes and their interactions are unknown. It is also unclear if benchside understanding of As carcinogenesis in model systems can be translated into bedside understanding of human cancer. In this R21/R33 proposal, this team of investigators will address these issues by adopting an integrated `omics approach that uses stable isotope-resolved metabolomics (SIRM) to define mt and cellular metabolic networks central to proliferation, redox homeostasis and oxidative DNA damage/repair response in lung cells, as perturbed by As transformation and carcinogenesis. This approach will reveal pathway changes for further testing on their dysregulations (e.g. key enzymes and related regulatory proteins) at the gene mutational, epigenetic, and transcriptional level by querying into genomic, epigenomic, and transcriptomic sequencing data. The investigators will fulfill their goal with two specific aims (SA1 & 2) in the R21 phase followed by SA3 & 4 in the R33 phase and SA1 to determine if and how mt and cellular metabolic networks are altered in As-transformed lung cells using SIRM. Transformed lung cells will be studied in vitro and in mouse xenografts using SIRM. The reprogrammed metabolic networks obtained will be related to those separately acquired in vivo from human lung cancer patients. SA2) to link ROS production, mt, and nuclear DNA damages/repair processes to metabolic reprogramming in As-transformed lung cells. Correlations of SA1&2 data will enable hypothesis generation for further testing of cause-and-effect relationships in SA3&4. SA3) to reveal cause-and-effect relations among altered Mt/cellular metabolic networks, ROS production, and DNA damage during As-induced transformation by their time-dependence. SA4) to map corresponding genetic, epigenetic and gene expression changes in As-transformed lung cells for hypothesis testing on As action. Next-generation sequence data will be acquired and queried for mutational signatures, epigenetic status, and mRNA expression of key genes involved in the reprogrammed metabolic networks, redox balance, and DNA repair. These data will help delineate how As-induced genetic or epigenetic lesions lead to metabolic reprogramming or vice versa. Such integration of genomic, epigenomic, transcriptomic, and metabolomics analysis of As action in model lung cell systems should provide unprecedentedly detailed insights into metabolic dysregulation and DNA damage in the mitochondria and how they may be linked to nuclear DNA damage and altered gene expression. The integrated `omics information will facilitate full-scale validation studies on the molecular mechanism for As-induced carcinogenesis and translation of such basic insights into human lung cancer resulting from As exposure (e.g. discovery of mechanistic and robust biomarker patterns).