INHIBITION OF CHEMICAL TRANSFORMATION BY ASPIRIN

阿司匹林对化学转化的抑制

• 批准号: 3181612
• 负责人: JOSEPH R LANDOLPH
• 金额: $ 13.25万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-05-01 至 1989-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3181612
• 关键词: aspirin; chemical carcinogen; chemical carcinogenesis; dexamethasone; eicosanoid metabolism; fatty acid metabolism; growth inhibitors; high performance liquid chromatography; indomethacin; leukotrienes; methylcholanthrene; prostaglandin endoperoxide synthase; prostaglandins; radioimmunoassay; tissue /cell culture

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.

我们将继续我们早先的发现，即阿司匹林抑制晚期高血压 C3H/10T1/2细胞的化学转化。我们将特别在 确定阿司匹林抑制细胞化学转化的机制 C3H/10T1/2细胞和前列腺素或其他二十烷基类化合物是否发挥作用 在C3H/10T1/2细胞化学转化后期的作用。 首先，我们将严格通过高效液相和放射免疫分析方法来确定 转换浓度的MCA会导致花生四烯酸释放和 C3H/10T1/2细胞中前列腺素和其他二十烷类化合物的生物合成 然后，我们将确定前列腺素或白三烯的水平 花生四烯酸代谢产物在细胞中减少 1 mU/ml 3-甲基氯乙烯在添加20%后转化 我们之前发现阿司匹林对细胞有明显的抑制作用 化学转化。我们将用抑制剂处理C3H/10T1/2细胞 花生四烯酸释放，如地塞米松，与抑制剂 环氧合酶，如阿司匹林、吲哚美辛和氟比洛芬，与 脂氧合酶活性的抑制剂(有些还抑制环氧合酶 活性)，例如5，6-脱氢-花生四烯酸，去甲二氢愈创木酸， 和BW 755C，并确定二十烷类化合物生物合成途径中的什么位置 对转化的抑制作用最大。这将对我们有帮助 重点关注要检测的二十烷类代谢物的最少数量 化学转化的推定增强剂。然后我们会研究 阿司匹林对细胞内部分纯化环氧合酶的抑制作用 C3H/10T1/2细胞组分。我们还将确定抑制是否 MCA对C3H/10T1/2细胞环氧合酶活性的影响 阿司匹林治疗与抑制化学转化相关 环氧合酶抑制剂阿司匹林和吲哚美辛。 其次，我们将加入花生四烯酸代谢物，这两种代谢产物都是通过 环氧合酶，也通过脂氧合酶途径，作用于C3H/10T1/2细胞 用起始浓度为0.1微克/毫升的MCA处理，并测定 这些代谢物是促进C3H/10T1/2细胞转化还是 1微克/毫升对细胞转化的逆转抑制作用 阿司匹林。在所有转换分析中，我们还将并行运行我们的 先前开发的检测哇巴因突变的方法 抗药性以确定是否对增强或抑制 与转型并行的是类似的增强或抑制 碱基替换突变。