Aldo-keto reductase- and cytochrome P450-dependent formation of benzo[a]pyrene-derived DNA adducts in human bronchoalveolar cells

Chem Res Toxicol. 2007 Mar;20(3):424-31. doi: 10.1021/tx060180b. Epub 2007 Feb 13.


There is substantial evidence to suggest that polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene (B[a]P) induce lung cancer through metabolic activation. As part of a program to delineate the routes of PAH activation, we have examined DNA adducts that are formed in human lung cells. A stable isotope dilution liquid chromatography/multiple reaction monitoring mass spectrometry method was used to quantify eight anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydro-B[a]P (B[a]PDE)-derived DNA adducts in four H358 human bronchoalveolar cell lines with different phenotypes. In P450 1A1/P450 1B1-induced H358 cells exposed to (+/-)-B[a]P-7,8-dihydro-7,8-diol (B[a]P-7,8-dihydrodiol), (+)-anti-trans-B[a]PDE-N2-2'-deoxyguanosine [(+)-anti-trans-B[a]PDE-N2-dGuo] was the major DNA adduct, and it formed with no lag phase. In AKR1A1-transfected H358 cells, (+)-anti-trans-B[a]PDE-N2-dGuo was also the major adduct with a 3 h lag phase before significant adduct formation was detected. In AKR1A1-transfected H358 cells with induced P450 1A1/P450 1B1, (+)-anti-trans-B[a]PDE-N2-dGuo was formed with no lag phase in amounts similar to those in the H358 cells with up-regulated P450 1A1/P450 1B1. Surprisingly, the greatest amount of (+)-anti-trans-B[a]PDE-N2-dGuo was formed in the control H358 cells. Furthermore, (+)-anti-trans-B[a]PDE-N2-dGuo formation was 2-fold higher in (-)-B[a]P-7,8-dihydrodiol-exposed H358 cells when compared with (+/-)-B[a]P-7,8-dihydrodiol-exposed cells. The P450 1A1/1B1 inhibitor 2,4,3',5'-tetramethoxystilbene did not attenuate DNA adduct formation in the control H358 cells, suggesting that another P450 was responsible. These data raise the intriguing possibility that P450 1A1/P450 1B1 and AKR1A1 may be protective against (+)-B[a]PDE-mediated DNA damage.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Alcohol Oxidoreductases / metabolism*
  • Aldehyde Reductase / metabolism*
  • Benzo(a)pyrene / metabolism*
  • Benzo(a)pyrene / toxicity*
  • Bronchoalveolar Lavage Fluid / cytology*
  • Cytochrome P-450 Enzyme System / metabolism*
  • DNA Adducts / drug effects*
  • DNA Adducts / isolation & purification
  • Humans
  • Hydrolysis
  • Polychlorinated Dibenzodioxins / toxicity
  • Spectrophotometry, Ultraviolet
  • Stereoisomerism
  • Teratogens / toxicity
  • Transfection


  • DNA Adducts
  • Polychlorinated Dibenzodioxins
  • Teratogens
  • Benzo(a)pyrene
  • Cytochrome P-450 Enzyme System
  • Alcohol Oxidoreductases
  • Aldehyde Reductase