TOXICOLOGICAL RELEVANCE OF HUMAN GST P-1 POLYMORPHISM

描述：（改编自研究者摘要）总体 本项目的目的是确定人类谷胱甘肽的意义 S-转移酶_（hGSTP 1 -1）基因多态性与肝细胞解毒作用的关系 多环芳烃的致癌二醇环氧化物（DE）， 是广泛存在的环境污染物， 人类化学致癌因素。 最近的初步研究 表明hGSTP 1 -1的两种多态性形式，其在它们的表达上不同， 一级结构由位置104处的单个氨基酸组成，显著 在它们对DE的活性上不同。 这些观察导致了 研究人员假设hGSTP 1 -1多态性可能是一种 个体对PAH诱导的不同反应的重要决定因素 癌 这一假设将通过一系列实验进行验证 四个相互关联的具体目标。 在具体目标1中，他们将比较 研究了三种天然产物的动力学参数和催化效率， hGSTP1-1（I104，A113），hGSTP1-1 (V104，A113）和hGST P1 -1（V104，V113）]和hGST P1 -1（I104，V113）形式，制备 通过定点诱变，在各种湾区的GSH缀合中， 和峡湾地区的DE。 在具体目标2中，我们将研究 hGSTP 1 -1变体的过表达，通过在HepG 2中稳定转染 细胞，抗BPDE和抗CDE的细胞毒性[最终致癌性 苯并（a）芘和金的代谢物]和对 抗BPDE的主要DNA加合物（trans-NdG-BPD加合物）。 具体目标3中的研究旨在确定 人中hGSTP 1 -1变体的表达（通过PCR，使用来自 正常健康受试者以及癌症患者）和GST活性， 抗BPDE，2反式-N dG-BPD加合物形成（在相同的白色血细胞中 个体）和血液癌症易感性（病史） 捐助者。 最后，具体目标4是阐明 hGSTP 1 -1变异体在GSH代谢中的动力学性质的差异 通过X射线晶体学和分子模拟的DE共轭 活性位点。 这些研究应加强我们对 对致癌DE的保护机制，也揭示了 hGSTP 1 -1基因多态性在小鼠解毒过程中的生理意义 这类终极致癌物。 从长远来看，信息 从这个项目产生的可能是有价值的制定战略， 人类癌症预防，并可能有助于确定人口在 PAH诱发癌症的风险。 拟议的研究将评估总共408个病例， 控制的数量。 人口将由男女成员组成 包括白人、黑人和其他少数民族， 慈善医院的病人代表

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.