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INHIBITION OF CHEMICAL TRANSFORMATION BY ASPIRIN

阿司匹林对化学转化的抑制

基本信息

批准号：
3181613
负责人：
JOSEPH R LANDOLPH
金额：
$ 12.15万
依托单位：
UNIVERSITY OF SOUTHERN CALIFORNIA
依托单位国家：
美国
项目类别：
财政年份：
1986
资助国家：
美国
起止时间：
1986-05-01 至 1990-04-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/3181613
关键词：
aspirin chemical carcinogen chemical carcinogenesis dexamethasone eicosanoid metabolism enzyme inhibitors enzyme mechanism fatty acid metabolism growth inhibitors high performance liquid chromatography indomethacin laboratory rat leukotrienes methylcholanthrene prostaglandin endoperoxide synthase prostaglandins radioimmunoassay tissue /cell culture

项目摘要

We will pursue our earlier findings that aspirin inhibits late stages of chemical transformation of C3H/10T1/2 cells. We will specifically in determine mechanisms by which aspirin inhibits chemical transformation of C3H/10T1/2 cells and whether prostaglandins or other eicosanoids play a role in late stages of chemical transformation of C3H/10T1/2 cells. Firstly, we will rigorously by HPLC and RIA methodologies determine whether transforming concentrations of MCA cause arachidonic acid release and biosynthesis of prostaglandins and other eicosanoids in C3H/10T1/2 cells. Then, we will determine whether levels of prostaglandin or leukotriene metabolites of arachidonic acid metabolism are reduced in cells undergoing transformation by 1Mu/ml 3-methylchlanthrene following addition of 20 Mug/ml of aspirin to cells, which we previously found markedly inhibits chemical transformation. We will treat C3H/10T1/2 cells with inhibitors of arachidoinic acid release, such as dexamethasone, with inhibitors of cyclooxygenase, such as aspirin, indomethacin, and flurbiprofen, with inhibitors of lipoxygenase acitivity (some also inhibit cyclooxygenase activity) such as 5,6 dehydro-arachidonic acid, nordihydroguariuretic acid, and BW 755C, and determine where in the eicosanoid biosynthetic pathway the greatest inhibitory effect is exerted on transformation. This will help us focus on the fewest number of eicosanoid metabolites to be examined as putative enhancers of chemcial transformation. We will then study aspirin-mediated inhibiton of partially purified cyclooxygenase in cell fractions of C3H/10T1/2 cells. We will also determine whether inhibition of cyclooxygenase activity in MCA-treated C3H/10T1/2 cells subsequently treated with aspirin correlates with inhibition of chemical transformation by the cyclooxygenase inhibitors aspirin and Indomethacin. Secondly, we will add arachidonic acid metabolites, both those formed via cyclooxygenase and also via the lipoxygenase pathways, to C3H/10T1/2 cells treated with an initiating concentration of MCA, 0.1 Mug/ml, and determine whether these metabolites enhance the transformation of C3H/10T1/2 cells or reverse inhibition of transformation incells treated with 1 Mug/ml of aspirin. In all transformation assays, we will also run in parallel our previously developed assay measuring induction of mutation to ouabain resistance to determine whether effects on enhancement of or inhibition of transformation are paralleled by similar enhancements or inhibitions of base substitution mutations.

我们将继续研究我们早期的发现，即阿司匹林抑制晚期阶段 C3H/10T1/2 细胞的化学转化。我们将专门在确定阿司匹林抑制化学转化的机制 C3H/10T1/2 细胞以及前列腺素或其他类二十烷酸是否发挥作用在 C3H/10T1/2 细胞化学转化后期的作用。首先，我们将通过HPLC和RIA方法严格确定是否 MCA 浓度的转化导致花生四烯酸释放和 C3H/10T1/2 细胞中前列腺素和其他类二十烷酸的生物合成。然后，我们将确定前列腺素或白三烯的水平细胞中花生四烯酸代谢物减少添加 20 后通过 1Mu/ml 3-甲基氯转化一杯/毫升的阿司匹林对细胞的作用，我们之前发现它显着抑制化学转变。我们将用抑制剂治疗 C3H/10T1/2 细胞花生四烯酸的释放，例如地塞米松，以及抑制剂环加氧酶，例如阿司匹林、吲哚美辛和氟比洛芬，脂氧合酶活性抑制剂（有些还抑制环氧合酶活性），例如5，6脱氢花生四烯酸、去甲二氢愈创木尿酸，和 BW 755C，并确定类二十烷酸生物合成途径中的位置对转化的抑制作用最大。这将帮助我们重点关注要检查的类二十烷酸代谢物的最少数量假定的化学转化增强剂。接下来我们将学习阿司匹林介导的细胞内部分纯化环加氧酶的抑制 C3H/10T1/2 细胞的分数。我们还将确定是否抑制随后 MCA 处理的 C3H/10T1/2 细胞中环氧合酶活性的变化阿司匹林治疗与化学转化的抑制相关由环氧合酶抑制剂阿司匹林和吲哚美辛引起。其次，我们将添加花生四烯酸代谢物，它们都是通过环加氧酶并通过脂氧合酶途径到达 C3H/10T1/2 细胞用起始浓度 MCA 0.1 Mug/ml 处理，并测定这些代谢物是否增强 C3H/10T1/2 细胞的转化或逆转用 1 Mug/ml 处理的细胞中的转化抑制阿司匹林。在所有转化测定中，我们还将并行运行我们的先前开发的测定法，测量哇巴因突变的诱导抗性以确定是否对增强或抑制有影响转化同时伴随着类似的增强或抑制碱基取代突变。