Influence of the metabolic properties of human cells on the kinetic of formation of the major benzo[a]pyrene DNA adducts.
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. Some of them, including benzo[a]pyrene (B[a]P), are tumorigenic due to their ability to generate DNA adducts. In order to define potential biomarkers of B[a]P exposure, the aim of the study was to identify the major stable DNA adducts in B[a]P-treated human cells. The role played by cellular metabolism on the nature and frequency of the DNA lesions was investigated using keratinocytes (HaCat) and actively metabolizing hepatocytes (HepG2) cell lines. Quantification of DNA damage was carried out by HPLC coupled to tandem mass spectrometry, a sensitive method making possible the selective detection of the different potential stable DNA adducts of B[a]P. These include two adducts of the 7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) pathway and three adducts of the radical cation pathway. The results indicate that incubation of cells with B[a]P induces almost exclusively the formation of BPDE DNA adducts on purine bases. The amount of DNA adducts generated in hepatocytes was found to be two orders of magnitude higher than that measured in keratinocytes. Interestingly, the level of the DNA adducts produced in the cells incubated with (+/-)-anti-BPDE was similar in the two cell lines, indicating that the difference observed upon incubation with B[a]P could be attributed to different kinetics of B[a]P metabolism. The repair rate of BPDE DNA adducts was identical in the two cell lines with a half-life estimated to be around 20 h. These data support the use of the stable BPDE DNA adducts, as relevant biomarkers of exposure to B[a]P.
Marie
Caroline
C
Laboratoire des Lésions des Acides Nucléiques, LCIB (UMR-E 3 CEA-UJF), DRFMC, CEA/Grenoble, 17 Avenue des Martyrs 38054 Grenoble Cedex 9, France.
Maître
Anne
A
Douki
Thierry
T
Gateau
Mathilde
M
Tarantini
Adeline
A
Guiraud
Pascale
P
Favier
Alain
A
Ravanat
Jean-Luc
JL
D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide / Q000378:metabolism / Q000633:toxicity; D001564:Benzo(a)pyrene / Q000378:metabolism* / Q000633:toxicity*; D002273:Carcinogens / Q000378:metabolism* / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002477:Cells / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D018736:DNA Adducts / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects; D004563:Electrochemistry; D004785:Environmental Pollutants / Q000378:metabolism* / Q000633:toxicity*; D006801:Humans; D007202:Indicators and Reagents; D015603:Keratinocytes / Q000187:drug effects / Q000378:metabolism; D007700:Kinetics; D009862:Online Systems; D053719:Tandem Mass Spectrometry; D013778:Tetrazolium Salts; D013844:Thiazoles
D002273:Carcinogens; D018736:DNA Adducts; D004785:Environmental Pollutants; D007202:Indicators and Reagents; D013778:Tetrazolium Salts; D013844:Thiazoles; D001564:Benzo(a)pyrene; D015123:7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide; C022616:thiazolyl blue