BIOCHEMICAL AND MOLECULAR STUDIES ON DT-DIAPHORASE

DT-黄递糖或NAD(P)H：苯醌氧化还原酶(NQO1) 在许多环境对苯二酚失活的关键作用和 外源生物，并已被认为是重要的在这两个 化学保护和化学预防。NQO1也吸引了 相当受关注，因为它有能力激活某些 生物还原抗肿瘤醌类化合物及其在肿瘤中的活性增强 作为非小细胞肺癌(NSCLC)。为了努力开发新的 对于非小细胞肺癌的药物治疗，我们将考察其创新能力 抗肿瘤醌类化合物作为人NQO1的底物并测试 假设被NQO1有效生物活性的化合物 对NQO1活性升高的NSCLC细胞具有选择性细胞毒作用。 同样重要的是要了解提升的基础机制 NQO1在非小细胞肺癌中的表达因此，我们 建议表征特定的顺式作用DNA序列和 介导非小细胞肺癌的核蛋白-DNA反式作用 NQO1的特异性表达。 我们已经确定了NQO1的多态性，这是一种纯合子 导致NQO1蛋白和酶完全丧失的突变 活性，尽管很容易检测到NQO1mRNA。我们会 确定对突变体hNQO1的调节是否处于 翻译或蛋白质不稳定，并定义蛋白质的变化 结构，这是突变的结果。NQO1是否 发挥任何生理作用或作用于内源底物 未知。我们的数据表明，NQO1可以再生抗氧化形式 在自由基攻击后α-生育酚的含量，这项观察将 在本申请中被继续使用。NQO1作为一种潜在的 抗氧化酶也可能起到化学预防作用。 NQO1。导致NQO1基因多态性的特征 NQO1蛋白和活性的完全丧失给了我们一个独特的 有机会研究缺乏NQO1与 人类对癌症的易感性。我们将研究 NQO1基因多态性在结肠癌患者中的分布 腺瘤，结肠癌发展的中间阶段， 和匹配的无疾病个体。拟议的研究代表了 化学、生物化学和分子综合方法 确定NQO1在生物还原药物激活中的意义 和化学预防。

DT-Diaphorose or NAD(P)H:quinone oxidoreductase (NQO1) plays a key role in the deactivation of many environmental quinones and xenobiotics and has been proposed to be important in both chemoprotection and chemoprevention. NQO1 has also attracted considerable attention because of its ability to activate certain bioreductive antitumor quinones and its elevated activity in tumors such as non small cell lung cancer (NSCLC). In an effort to develop new agents for the therapy of NSCLC, we will examine the ability of novel antitumor quinones to serve as substrates for human NQO1 and test the hypothesis that compounds which are efficiently bioactivated by NQO1 are selectively cytotoxic to NSCLC cells with elevated NQO1 activity. It is also critical to understand the mechanisms underlying the elevated expression of NQO1 in NSCLC relative to SCLC. We therefore propose to characterize the specific cis-acting DNA sequences and trans-acting nuclear protein-DNA interactions that mediate NSCLC specific expression of NQO1. We have characterized a polymorphism in NQO1, a homozygous mutation which leads to a total loss of NQO1 protein and enzyme activity, although NQO1 mRNA can readily be detected. We will determine if regulation of the mutant hNQO1 is at the level of translation or protein instability and define the alterations in protein structure which occur as a result of the mutation. Whether NQO1 plays any physiological role or acts on endogenous substrates is as yet unknown. Our data suggests that NQO1 regenerates antioxidant forms of alpha-tocopherol after free radical attack and this observation will be pursued in this application. The potential role of NQO1 as an antioxidant enzyme may also contribute to the chemopreventive role of NQO1. The characterization of a polymorphism in NQO1 which leads to a total loss of NQO1 protein and activity gives us a unique opportunity to examine the association between lack of NQO1 and susceptibility to cancer in a human population. We will examine the prevalence of the NQO1 polymorphism in patients with colon ademomas, an intermediate stage in the development of colon cancer, and matched disease-free individuals. The proposed studies represent an integrated chemical, biochemical and molecular approach to determining the significance of NQO1 for bioreductive drug activation and chemoprevention.