title: Detection of benzo(a)pyrene diol epoxide-DNA adducts in mononuclear white blood cells by CE immunoassay and its application to studying the effect of glutathione depletion.
abstract: High levels of benzo(a)pyrene diol epoxide (BPDE)-DNA adducts in white blood cells have been indicated as a risk factor for lung cancer. Sensitive, specific, fast and cost-efficient techniques for the detection of BPDE-DNA adducts in white blood cells are required for routine human biomonitoring. In the present study, an immunoassay based on CE/LIF was developed for the detection of BPDE-DNA adducts in mononuclear white blood cells (MNCs). Although glutathione (GSH) conjugation catalyzed by glutathione-S-transferase (GST) is considered to be the major pathway for inactivating BPDE, the effect of GSH depletion on BPDE-DNA adduct formation in MNCs has not been assessed. Therefore, we applied the newly developed method to study the effect of GSH depletion by D,L-buthionine-[S,R]-sulfoximine (BSO) on the level of DNA adducts. We found that pretreatment of MNCs with 150 microM BSO for 2 h prior to BPDE exposure increased the level of BPDE-DNA adducts appreciably (by approximately 70%). Further investigations revealed that the 2-h BSO treatment neither decreased the GSH level instantly nor affected GST activity; rather, it prevented the induction of GSH in response to subsequent BPDE incubation. The blocked synthesis of GSH might be responsible for the elevated level of BPDE-DNA adducts in MNCs after BSO and BPDE treatment.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alta, Canada.
authors.forename: Adrienne
authors.initials: A
authors.lastname: LeBlanc
authors.forename: Shengwen
authors.initials: S
authors.lastname: Shen
authors.forename: Kristi
authors.initials: K
authors.lastname: Lew
authors.forename: Michael
authors.initials: M
authors.lastname: Weinfeld
authors.forename: X Chris
authors.initials: XC
authors.lastname: Le