TOXICOLOGICAL RELEVANCE OF HUMAN GST PL-L POLYMORPHISM

人类 GST PL-L 多态性的毒理学相关性

• 批准号: 6164620
• 负责人: Shivendra Singh
• 金额: $ 7.2万
• 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 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6164620
• 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：（根据调查员的摘要进行了改编）总体 该项目的目的是定义人谷胱甘肽的重要性 S-转移酶_（HGSTP1-1）在细胞解毒的多态性 多环芳烃的致癌二醇环氧化物（DES），该环氧化物（DES） 是广泛的环境污染物，被认为是病因 人类化学癌变的因素。 最近的初步研究 表明HGSTP1-1的两种多态性形式在其上有所不同 单个氨基酸的一级结构在104的位置显着 他们对DES的活动有所不同。 这些观察结果领导了 研究人员假设HGSTP1-1多态性可能是 个体对PAH诱导的可变响应的重要决定因素 癌症。 该假设将通过提出的一系列实验来检验 在四个相互关联的特定目标下。 在特定目标1中，他们将比较 动力学参数和三个天然的催化效率 HGSTP1-1的多态性形式[HGSTP1-1（I104，A113），HGSTP1-1 （V104，A113）和HGSTP1-1（V104，V113）]和HGSTP1-1（I104，V113）形式，准备 通过位置定向的诱变，在各种海湾区域的GSH结合中 和峡湾区。 在特定目标2中，我们将研究 HGSTP1-1变体的过表达，通过HEPG2中的稳定转染 细胞，抗BPDE和抗CDE的细胞毒性[最终致癌性 苯并（A）pyrene和Chrysene的代谢产物和形成 OF2抗BPDE的主要DNA加合物（Trans-N DG-BPD加合物）。 特定目标3中的研究旨在确定 人类中HGSTP1-1变体的表达（通过使用来自PCR的血液样本 正常健康受试者以及癌症患者）和GST活动 抗BPDE，2 trans-n dg-bpd加合物形成（在同一白细胞中 个体）和对血液的癌症（病史）的敏感性 捐助者。 最后，具体目标4是阐明的分子机制 GSH中HGSTP1-1变体的动力学特性的差异 通过X射线晶体学和分子建模的DES结合 活动地点。 这些研究应增强我们对 防止致癌的保护机制，并阐明 HGSTP1-1多态性在解毒中的生理意义 这类最终致癌物。 从长远来看，信息 该项目产生的可能对制定策略的有价值 人类预防癌症，可能有助于确定人口 PAH诱导的癌症的风险。 拟议的研究将评估总共408个案例和同等的情况 控件数。 人口将由两个性别的成员组成 并将包括可用的高加索人，黑人和其他少数民族， Mercy医院的患者基础代表。