Mass spectrometric analysis of 4-hydroxy-1-(3-pyridyl)-1-butanone-releasing DNA adducts in human lung

An improved analytical method was developed for the analysis of 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB)-releasing DNA adducts in lung samples of patients undergoing surgery for lung cancer. HPB-releasing adducts can be formed by metabolic activation of the tobacco-specific nitrosamines 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and N′-nitrosonornicotine, and have been reported to play an important role in tobacco carcinogenesis. [2,2,3,3-D4]HPB (D4-HPB) was used as an internal standard, and HPB released by acid hydrolysis of DNA was determined by gas chromatography/mass spectrometry in the negative ion chemical ionisation mode. The method is sensitive with a limit of detection of 5.9 fmol HPB and a limit of quantification of 15.2 fmol HBP/mg DNA. The recovery of HPB was 82 ± 17% and the background response was 10.1 ± 1.8 fmol HPB/sample. The concentration of HPB-releasing lung DNA adducts was significantly higher (p < 0.0001) in 21 self-reported smokers compared to in 11 self-reported nonsmokers (404 ± 258 fmol versus 59 ± 56 fmol HPB/mg DNA, respectively). HPB-releasing hemoglobin adduct concentrations were only marginally higher in a subset of 12 smokers compared to in 7 nonsmokers (63 ± 53 fmol versus 42 ± 34 fmol HPB/g hemoglobin; p = 0.36). No correlation was found between HPB-releasing adducts in DNA and hemoglobin (p = 0.074).