Impact of GST polymorphisms on hemoglobin adducts in smokers and non-smokers

Abstract

Adducts formed by the reaction of chemicals or their metabolites with hemoglobin provide a means to estimate exposure to chemical carcinogens. The objectives of this study were to develop methods that can be used to measure hemoglobin adducts using liquid chromatography with tandem mass spectrometry with the modified Edman degradation method for adducts with the N-terminal valine residues, and apply these methods to samples from smokers and non-smokers for carcinogenic compounds (or their metabolites) in cigarette smoke. LC-MS methods have been developed for the measurement of cyanoethylvaline (CEVal from acrylonitrile), hydroxyethylvaline (HEVal from ethylene/ethylene oxide), carbamoylethylvaline (AAVal from acrylamide), carbamoylhydroxyethylvaline (GAVal from glycidamide). For simultaneous analysis of adducts, we measured HEVal, CEVal, GAVal and AAVal in hemoglobin from smokers and non-smokers obtained previously in which the impact of GST T1 and GST M1 had been investigated using GC-MS methods for analysis of CEVal and HEVal (Fennell, T. R., MacNeela, J. P., Morris, R. W., Watson, M., Thompson, C. L. and Bell, D. A. 2000. Cancer Epidemiol Biomarkers Prev 9:705-12). CEVal measured by LC-MS agreed well with previous measurements made by GC-MS methods. HEVal and CEVal were elevated in smokers compared with non-smokers. We have previously found CEVal to provide a useful marker of cigarette smoke intake. Both AAVal and GAVal were higher in non-smokers than CEVal, and increased with increasing CEVal in smokers. AAVal ranged from 31-130 fmol/mg globin (mean = 58) in nonsmokers, presumably due to exposure to acrylamide in the diet. AAVal increased in smokers to 69-254 fmol/mg globin (means of 124 and 157 fmol/mg globin in 1- and 2-pack/day smokers). The GST T1 and GST M1 genotype did not appear to influence the level of either AAVal or GAVal, suggesting that these enzymes do not play a significant role in the metabolism of AM or GA.