TOXICOLOGICAL RELEVANCE OF HUMAN GST P-1 POLYMORPHISM

人类 GST P-1 多态性的毒理学相关性

• 批准号: 2468872
• 负责人: Shivendra Singh
• 金额: $ 17.66万
• 依托单位: MERCY HOSPITAL OF PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2002-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2468872
• 关键词: X ray crystallography; adduct; cancer risk; carbopolycyclic compound; chemical carcinogen; chemical carcinogenesis; clinical research; detoxification; environmental toxicology; enzyme activity; enzyme structure; epoxides; gene environment interaction; genetic polymorphism; genetic susceptibility; glutathione transferase; human subject; isozymes; neoplasm /cancer genetics; polymerase chain reaction; tissue /cell culture; transfection

DESCRIPTION: (Adapted from the Investigator's Abstract)The overall objective of this project is to define the significance of human glutathione S-transferase _ (hGSTP1-1) polymorphism in cellular detoxication of carcinogenic diol epoxides (DEs) of polycyclic aromatic hydrocarbons, which are widespread environmental pollutants and believed to be etiological factors in human chemical carcinogenesis. Recent preliminary studies indicate that the two polymorphic forms of hGSTP1-1, which differ in their primary structure by a single amino acid in position 104, significantly differ in their activity toward DEs. These observations led the investigators to hypothesize that the hGSTP1-1 polymorphism may be an important determinant of variable response of individuals to PAH-induced cancer. This hypothesis will be tested by a series of experiments proposed under four interrelated specific aims. In specific aim 1, they will compare the kinetic parameters and catalytic efficiencies of three naturally occurring polymorphic forms of hGSTP1-1 [hGSTP1-1(I104,A113), hGSTP1-1 (V104,A113) and hGSTP1-1(V104,V113)] and hGSTP1-1(I104,V113) form, prepared by site-directed mutagenesis, in the GSH conjugation of various bay-region and fjord-region DEs. In specific aim 2, we will investigate the effects of overexpression of hGSTP1-1 variants, through stable transfection in HepG2 cells, on cytotoxicity of anti-BPDE and anti-CDE [ultimate carcinogenic metabolite of benzo(a)pyrene and chrysene, respectively] and on formation of2 the predominant DNA adduct of anti-BPDE (trans-N dG-BPD adduct). Studies in specific aim 3 are designed to determine the correlation between expression of hGSTP1-1 variants in humans (by PCR using blood samples from normal healthy subjects as well as cancer patients) and GST activity toward anti-BPDE,2 trans-N dG-BPD adduct formation (in white blood cells of same individuals) and susceptibility to cancer (medical history) of the blood donors. Finally, specific aim 4 is to elucidate the molecular mechanism of differences in the kinetic properties of hGSTP1-1 variants in the GSH conjugation of DEs by X-ray crystallography and molecular modeling of their active sites. These studies should enhance our understanding of the protective mechanisms against carcinogenic DEs and also shed light on the physiological significance of hGSTP1-1 polymorphism in the detoxication of this class of ultimate carcinogens. In the long term, the information generated from this project may be valuable in formulating strategies for cancer prevention in humans and may help in identifying human population at risk for PAH-induced cancer. The proposed studies will assess a total of 408 cases plus and an equal number of controls. The population will consist of members of both genders and will include Caucasians, blacks and other minorities, as available and representative of the patient base at Mercy Hospital.

描述：(改编自《调查者摘要》) 本项目的目的是确定人类谷胱甘肽的意义 S-转移酶_(hGSTP1-1)基因多态性与小鼠细胞解毒 致癌的多环芳烃二醇环氧化物(DES)，其 是广泛存在的环境污染物，被认为是致病因素 人类化学致癌的因素。最近的初步研究 表明hGSTP1-1的两种不同的多态形式 由104位的单一氨基酸构成的一级结构，显著 它们对DES的活动是不同的。这些观察结果导致了 研究人员假设hGSTP1-1基因多态可能是一种 个体对多环芳烃诱导的可变反应的重要决定因素 癌症。这一假设将通过提出的一系列实验来检验。 在四个相互关联的具体目标下。在具体目标1中，他们将比较 三种天然产物的动力学参数和催化效率 HGSTP1-1[hGSTP1-1(I104，A113)，hGSTP1-1 (V104，A113)和hGSTP1-1(V104，V113)]和hGSTP1-1(I104，V113)表格，制备 通过定点突变，在不同湾区的GSH结合 和峡湾地区的DES。在具体目标2中，我们将调查 HGSTP1-1变异体在HepG2中的稳定表达 细胞，对抗BPDE和抗CDE[终极致癌物质]的细胞毒性 分别是苯并(A)芘和大黄烯的代谢物]和形成 Of2主要是抗BPDE的DNA加合物(反式-N-DG-BPD加合物)。 在特定目标3中的研究旨在确定 HGSTP1-1变异体在人类中的表达(通过对来自中国的血液样本进行聚合酶链式反应) 正常健康人以及癌症患者)和GST活性 抗BPDE，2-反式-N-DG-BPD加合物形成(在其白细胞中 个人)和血液对癌症的易感性(病史) 捐赠者。最后，特定的目的4是阐明分子机制。 HGSTP1-1变异体在GSH中动力学性质的差异 DES的X射线结晶学偶联及其分子模拟 活动站点。这些研究应该会加深我们对 对致癌DES的保护机制，也揭示了 HGSTP1-1基因多态性在解毒中的生理意义 这类终极致癌物质。从长远来看，这些信息 从这个项目中产生的可能在制定战略方面有价值 在人类中预防癌症，并可能有助于在 多环芳烃诱发癌症的风险。 拟议的研究将评估总共408个加和相等的病例。 控件的数量。人口将由男女成员组成 并将包括高加索人、黑人和其他少数民族，视情况而定 仁慈医院患者群的代表。