Ethanol and acetaldehyde enhance benzo[a]pyrene-DNA adduct formation in human mammary epithelial cells

In summary, the nonneoplastic human epithelial cell line MCF-10F metabolizes B[a]P predominantly to a B[a]P-DNA adduct tentatively identified as an anti-B[a]P-dihydrodiol epoxide-dGuo adduct. When cells are exposed to physiologically-relevant concentrations of either ethanol or acetaldehyde prior to dosing with B[a]P, adduct formation is increased. This enhancement of B[a]P-DNA adduct formation by ethanol in part may be explained by reduced GSTP1-1 protein expressed in the ethanol-treated cells. These results provide evidence that a possible mechanism by which alcohol intake may be enhancing breast cancer risk in humans is through an ethanol- and acetaldehyde-associated increase in carcinogen-DNA adducts in the target mammary epithelial cells. The mechanisms for this action of ethanol and acetaldehyde warrant further study.