Effects of chemopreventive agents on DNA damage response

化学预防剂对 DNA 损伤反应的影响

• 批准号: 7044530
• 负责人: J CHRISTOPHER STATES
• 金额: $ 7.35万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-27 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7044530
• 关键词: DNA damage; DNA repair; adduct; benzopyrenes; cancer prevention; cell cycle; chemoprevention; chemosensitizing agent; combination chemotherapy; environmental exposure; gene expression; lung neoplasms; p53 gene /protein; pharmacokinetics; respiratory epithelium; western blottings

DESCRIPTION (provided by applicant): Benzo[a]pyrene (B[a]P) is a prototypical polycyclic aromatic hydrocarbon produced by incomplete combustion and is a major carcinogen present in cigarette smoke and charred foods. PAH such as B[a]P are major environmental pollutants and exposure is widespread. The highly reactive and mutagenic B[a]P metabolite (+)-7R,8S-dihydroxy-9S,10R-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) is believed to play a significant role in human lung carcinogenesis. Chemoprevention is a relatively new and promising strategy to prevent cancer. Chemopreventive agents such as genistein, curcumin and resveratrol have a number of molecular targets, impact several signalling pathways and have strong antiproliferation effects on lung, breast, prostate and colon cancers. These three constituents have received a great deal of attention recently as cancer chemoprotective agents. Little work has been done to investigate the chemoprevention effects of genistein, resveratrol and curcumin with respect to PAH-induced DNA damage and repair responses. The global genomic repair component of nucleotide excision repair is regulated by p53 induction in response to DNA damage. P53 is induced in a dose and time-dependent manner after DNA damage. Low dose BPDE which is known to be mutagenic fails to induce the p53 mediated response to DNA damage. Our preliminary results suggest that pretreatment with a combination of resveratrol and curcumin enables p53 induction by low dose BPDE exposure. We hypothesize that chemopreventive agents may "sensitize" the cell to respond to low dose genotoxicant induced DNA damage through induction of p53 which activates global genomic DNA repair process allowing more efficient DNA repair. This study aims to investigate the effects of chemoprevention agents on cellular responses to BPDE-induced DNA damage in human lung cells. We aim to determine mechanism and effects of chemopreventive agents (singly and in combination) on p53 mediated regulation of (1) cell cycle progression and (2) DNA repair induction. Experimental approaches will include western blot to measure p53 and regulated signaling proteins in human lung cells and measure BPDE-induced DNA adduct formation and repair rate by 32P-post-labeling analyses. The results will likely illuminate a chemoprevention mechanism and also provide a deeper understanding of the mechanism of DNA damage and repair under a more physiologically relevant environmental exposure dose.

描述（由申请人提供）： 苯并[a]芘 (B[a]P) 是一种典型的多环芳烃，由不完全燃烧产生，是香烟烟雾和烧焦食品中存在的主要致癌物。 B[a]P 等多环芳烃是主要的环境污染物，接触情况十分普遍。高反应性和诱变性的 B[a]P 代谢物 (+)-7R,8S-二羟基-9S,10R-环氧-7,8,9,10-四氢苯并[a]芘 (BPDE) 被认为发挥着重要作用在人类肺癌发生过程中。化学预防是一种相对较新且有前途的癌症预防策略。金雀异黄素、姜黄素和白藜芦醇等化学预防剂具有许多分子靶点，影响多种信号传导途径，并对肺癌、乳腺癌、前列腺癌和结肠癌具有强大的抗增殖作用。这三种成分最近作为癌症化学保护剂受到了极大的关注。关于金雀异黄素、白藜芦醇和姜黄素对 PAH 诱导的 DNA 损伤和修复反应的化学预防作用的研究还很少。核苷酸切除修复的整体基因组修复部分受到 DNA 损伤反应中 p53 诱导的调节。 DNA 损伤后，P53 以剂量和时间依赖性方式被诱导。已知具有诱变性的低剂量 BPDE 不能诱导 p53 介导的 DNA 损伤反应。我们的初步结果表明，白藜芦醇和姜黄素组合的预处理能够通过低剂量 BPDE 暴露诱导 p53。我们假设化学预防剂可能通过诱导 p53 使细胞“敏感”，以响应低剂量基因毒物诱导的 DNA 损伤，p53 激活全局基因组 DNA 修复过程，从而实现更有效的 DNA 修复。本研究旨在研究化学预防剂对人肺细胞中 BPDE 诱导的 DNA 损伤的细胞反应的影响。我们的目标是确定化学预防剂（单独和联合）对 p53 介导的 (1) 细胞周期进程和 (2) DNA 修复诱导调节的机制和影响。实验方法将包括通过蛋白质印迹法测量人肺细胞中的 p53 和调节信号蛋白，并通过 32P 标记后分析测量 BPDE 诱导的 DNA 加合物形成和修复率。这些结果可能会阐明化学预防机制，并且还可以更深入地了解在更生理相关的环境暴露剂量下 DNA 损伤和修复的机制。