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Gaikwad NW, Bodell WJ: Formation of DNA adducts in HL-60 cells treated with the toluene metabolite p-cresol: a potential biomarker for toluene exposure. Chem Biol Interact. 2003 May 6;145(2):149-58.
We have examined DNA adduct formation in myeloperoxidase containing HL-60 cells treated with the toluene metabolite p-cresol. Treatment of HL-60 cells with the combination of p-cresol and H (2) O (2) produced four DNA adducts 1: (75.0%), 2: (9.1%), 3: (7.0%) and 4: (8.8%) and adduct levels ranging from 0.3 to 33.6 x 10 (-7). The levels of DNA adducts formed by p-cresol were dependent on concentrations of p-cresol, H (2) O (2) and treatment time. In vitro incubation of p-cresol with myeloperoxidase and H (2) O (2) produced three DNA adducts 1: (40.5%), 2: (28.4%) and 3: (29.7%) with a relative adduct level of 0.7x10 (-7). The quinone methide derivative of p-cresol (PCQM) was prepared by Ag (I) O oxidation. Reaction of calf thymus DNA with PCQM produced four adducts 1: (18.5%), 2: (36.4%), 3: (29.0%) and 5: (16.0%) with a relative adduct level 1.6x10 (-7). Rechromatography analyses indicates that DNA adducts 1-3 formed in HL-60 cells treated with p-cresol and after myeloperoxidase activation of p-cresol were similar to those formed by reaction of DNA with PCQM. This observation suggests that p-cresol is activated to a quinone methide intermediate in each of these activation systems. Taken together, these results suggest PCQM is the reactive intermediate leading to the formation of DNA adducts in HL-60 cells treated with p-cresol. Furthermore, the DNA adducts formed by PCQM may provide a biomarker to assess occupational exposure to toluene. |
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