Polyphenol associated-DNA adducts in lung and blood mononuclear cells from lung cancer patients

Abstract

The formation of smoking induced-DNA adducts is a critical factor in the induction of human lung cancer. As derivates of benzene and polyaromatic hydrocarbons (PAHs) are important compounds of tobacco smoke, in DNA isolated from human lung and blood mononuclear cells (MNCs) from 38 lung cancer patients, we used the 32P-postlabeling assay to detect polyphenol associated DNA adducts. Two DNA adducts were detected in blood MNCs and lung tissue that co-chromatographed with DNA modifications from HL60 cells treated with combinations of benzene metabolites (e.g., hydroquinone and benzenetriol). These adducts were designated polyphenol-associated DNA adducts. Relative adduct levels for polyphenolic adducts were five-fold higher than aromatic adducts in both lung and MNCs. A significant correlation was observed between levels of polyphenol adducts and total duration of cigarette smoking in lung ( r=0.34; P<0.04) and MNCs ( r=0.7; P<0.04), but no correlation between levels of polyphenol adducts and pack-years consumption of cigarettes nor time since quitting smoking in former smokers. Long term former smokers and the one non-smoker in the study had detectable levels of polyphenol adducts. Surprisingly, the levels of polyphenol adducts in MNCs were highly correlated with aromatic adduct levels ( r=0.84; P<0.001). Individual aromatic adducts in MNCs also correlated with polyphenol adducts. Total polyphenol adduct levels had a correlation with aromatic DNA adduct levels in lung tissue ( r=0.46; P<0.01). To our knowledge these results are the only comparison of adducts in MNCs with lung tissue, and the only data set indicating that blood MNCs are a valid surrogate for lung adduct DNA burden.