BIOACTIVATION OF DIETARY PHENOLS BY HEMOPROTEINS

血蛋白对膳食酚类的生物活性

• 批准号: 6341884
• 负责人: JOHN A THOMPSON
• 金额: $ 21.8万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-30 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6341884
• 关键词: DNA damage; animal genetic material tag; butylated hydroxytoluene; carcinogen testing; chemical carcinogenesis; cytochrome P450; dietary constituent; drug metabolism; enzyme activity; enzyme induction /repression; enzyme inhibitors; glutathione transferase; laboratory mouse; lung neoplasms; metallothionein; mutagen testing; mutagens; neoplasm /cancer genetics; nutrition related tag; quinones; tissue /cell culture; tumor promoters

The long-term goal of this research is to elucidate the underlying mechanisms by which phenolic compounds present in the human diet influence tumorigenesis. Ongoing studies demonstrates that the oxidative metabolism of alkylphenols by cytochromes P450 lead, in many cases, to the formation of quinoid products capable of covalent binding and/or free radical generation in cells. We now propose to extend this work to investigate the involvement of such reactive metabolites in tumor promotion utilizing the most thoroughly characterized model for probing mechanistic aspects of promotion in the lung. This system involves the enhancement of lung tumor development by chronic administration of the food additive butylated hydroxytoluene (BHT) to carcinogen-initiated mice. It has been demonstrated that metabolism of BHT in the target organ is necessary for promotion and it is known that BHT is converted to reactive quinoid metabolites in lung. These findings lead to the hypothesis that promotion depends upon two successive P450 catalyzed oxidations to the ultimate promoting species, a strongly electrophilic quione methide which alkylates one or more critical proteins leading to a disruption of growth control mechanisms. The following specific aims are proposed: (1) Determine the role of metabolism in the differential responsiveness of promotion- sensitive (B+) and promotion-resistant (B-) mice to the lung tumor promoter BHT. Conversion of BHT to a quinone methide and other reactive metabolites, as well as the detoxification of reactive metabolites, will be examined in lung tissues and cells from B+ and B- mice. (2) Investigate alkylation targets of a BHT-derived quinone methide in lung cells that directly or indirectly impair cell-cell signaling. Protein alkylation by a highly reactive quinone methide metabolite of BHT will be examined in cells isolated from the lungs of B= and B- mice, and in tumorigenic and non-tumorigenic cell lines derived from murine lung. Alkylation patterns will be compared by radiochemical and immunochemical methods and selected adducts identified by mass spectrometry and microsequencing. (3) Examine biochemical consequences and oxidative damage in lung cells exposed to reactive metabolites of BHT. Isolated cells from B+ and B- mice and cell lines will be treated with reactive quinoid metabolites of BHT to investigate cytotoxicity, oxidative damage, inhibition of mitochondrial function, and inhibition of enzymes involved in detoxification.

这项研究的长期目标是阐明基础 人类饮食中存在酚类化合物影响的机制 肿瘤发生。正在进行的研究表明氧化代谢 在许多情况下，细胞色素P450铅通过烷基苯酚的形成 能够共价结合和/或自由基的奎因类产品的 在细胞中产生。我们现在建议扩展这项工作，以调查 这种反应性代谢产物参与利用肿瘤促进 最彻底的特征模型，用于探测机械方面 在肺中促进。该系统涉及增强肺部肿瘤 长期给药食品添加剂丁基的开发 羟基甲苯（BHT）至致癌物引起的小鼠。它一直 证明BHT在目标器官中的代谢是必要的 促进，众所周知，BHT转化为反应性奎因 肺中的代谢产物。这些发现导致了促进的假设 取决于连续的P450催化氧化到最终 促进物种，一种强烈的亲电奎因甲基，烷基化 一种或多种关键蛋白质导致增长控制的破坏 机制。提出了以下特定目标：（1）确定 代谢在促进的差异反应性中的作用 - 敏感（B+）和抗促进性（B-）小鼠对肺肿瘤 发起人BHT。 BHT转换为醌甲基和其他反应性 代谢物以及反应性代谢产物的排毒将 在B+和B小鼠的肺组织和细胞中检查。 （2）调查 BHT衍生的喹酮甲基在肺细胞中的烷基化靶标的 直接或间接损害细胞 - 细胞信号传导。蛋白质烷基化 BHT的高反应性醌代谢物将在 从B =和B-小鼠的肺中分离出来的细胞，在肿瘤中和 源自鼠肺的非肿瘤细胞系。烷基化模式 将通过放射化学和免疫化学方法进行比较，并选择 通过质谱和微链测序确定的加合物。 （3）检查 暴露于肺部细胞的生化后果和氧化损伤 BHT的反应性代谢物。来自B+和B小鼠和细胞的分离细胞 线条将用BHT的反应性喹啉代谢物处理 研究细胞毒性，氧化损伤，抑制线粒体 功能和抑制参与排毒的酶。