BIOACTIVATION OF DIETARY PHENOLS BY HEMOPROTEINS

这项研究的长期目标是阐明潜在的 人类饮食中酚类化合物的作用机制 肿瘤发生学。正在进行的研究表明，氧化代谢 在许多情况下，由细胞色素P450导致烷基酚的形成 能够共价结合和/或自由基的类奎宁产品 在细胞中生成。我们现在建议将这项工作扩大到调查 这些反应性代谢产物在肿瘤促进中的作用 探索机械方面的最彻底的特征化模型 在肺中升迁。这个系统涉及到肺部肿瘤的增强 长期服用丁基化食品添加剂的研究进展 羟基甲苯(BHT)对致癌物引发的小鼠的毒性。一直以来 证明了BHT在靶器官中的代谢是 促进，并已知BHT被转化为反应性奎宁 肺部的代谢物。这些发现导致了一种假设，即晋升 依赖于两个连续的P450催化的氧化最终 促进剂，一种强亲电性的烷基化喹酮甲基化合物 一种或多种导致生长控制中断的关键蛋白质 机械装置。提出了以下具体目标：(1)确定 新陈代谢在晋升的不同反应中的作用- 对肺癌敏感(B+)和促进抵抗(B-)的小鼠 启动子BHT。BHT转化为对苯二酚和其他活性物质 代谢物以及反应性代谢物的解毒作用 在B+和B-小鼠的肺组织和细胞中进行检测。(2)调查 BHT衍生的苯二酚甲醚在肺细胞中的烷基化靶标 直接或间接损害细胞间的信号传递。蛋白质的烷基化反应 BHT的一种高活性的苯醌甲基代谢物将在 从B=和B-小鼠的肺中分离的细胞，以及在致瘤和 小鼠肺来源的非致瘤细胞系。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 经质谱学和显微测序鉴定的加合物。(三)审查 接尘对肺细胞生化和氧化损伤的影响 BHT的反应性代谢物。分离的B+和B-小鼠细胞及细胞 LINE将被BHT的活性奎宁代谢物处理以 研究线粒体的细胞毒性、氧化损伤和抑制 功能，以及参与解毒的酶的抑制。

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.