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Formation of DNA adducts in HL-60 cells treated with the toluene metabolite p-cresol: a potential biomarker for toluene exposure

2003; Elsevier BV; Volume: 145; Issue: 2 Linguagem: Inglês

10.1016/s0009-2797(02)00249-1

1872-7786

Nilesh W. Gaikwad, William J. Bodell,

Toxic Organic Pollutants Impact

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 H2O2 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 33.6×10−7. The levels of DNA adducts formed by p-cresol were dependent on concentrations of p-cresol, H2O2 and treatment time. In vitro incubation of p-cresol with myeloperoxidase and H2O2 produced three DNA adducts 1: (40.5%), 2: (28.4%) and 3: (29.7%) with a relative adduct level of 0.7×10−7. 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 1.6×10−7. 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.