ANALYSIS OF BENZO(A)PYRENE - DNA ADDUCTS FORMED IN CELLS IN CULTURE BY IMMOBILIZED BORONATE CHROMATOGRAPHY

  • 1 January 1984
    • journal article
    • research article
    • Vol. 44  (9) , 4104-4110
Abstract
A chromatographic procedure using boronic acid residues linked to a cellulose support ({{N-{N''-[m-(dihydroxyboryl)-phenyl]succinamyl}amino}}ethyl cellulose), used by Sawicki et al. for analysis of 7,12-dimethylbenz(a)anthracene:DNA adducts, was modified to allow the analysis of benzo(a)pyrene (BaP):DNA adducts formed in cells [human, HepG2] in culture. Adducts resulting from reaction of 7.beta.,8.alpha.-dihydroxy-9.alpha.,10.alpha.-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (anti-BaPDE) contain cis-vicinal hydroxyl groups that complex with the boronic acid residues; adducts resulting from 7.beta.,8.alpha.-dihydroxy-9.beta.,10.beta.-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (syn-BaPDE) do not. A mixture of [3H]-syn-BaPDE:deoxyguanosine (dGuo) adduct and [14C]-anti-BaPDE:dGuo adduct was completely resolved on a column of boronate:cellulose. Early-passage cultures of Sencar mouse, Syrian hamster and Wistar rat embryo cells and a culture of a human hepatoma cell line (Hep G2) were exposed to [3H]BaP and the BaP:DNA adducts were resolved by boronate chromatography and high-performance liquid chromatography. The Hep G2 cells and mouse embryo cells contained 2 major adducts, a (+)-anti-BaPDE:dGuo adduct and a syn-BaPDE:dGuo adduct. Boronate chromatography permitted the resolution of an additional minor syn-BaPDE:deoxyribonucleoside adduct in the mouse embryo cells. The hamster and rat embryo cells contained a number of major BaP-DNA adducts that were resolved by boronate chromatography followed by high-performance liquid chromatography. The rat embryo cells contained 3 syn-BaPDE:deoxyribonucleoside adducts and approximately equal amounts of 2 adducts tentatively identified as dGuo adducts of the (+) and (-) enantiomers of anti-BaPDE. The boronate chromatography-high-performance liquid chromatography procedure improves the separation of the BaP:DNA adducts formed in biological systems and facilitates the identification of the BaP metabolites(s) responsible for the formation of these adducts.

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