Cigarette smoking is an established risk factor for oral cancer. The health effects of e-cigarettes are still under investigation but may disturb oral cavity homeostasis and cause lung and cardiovascular diseases. Carcinogens and toxicants in tobacco products and e-cigarettes may damage DNA, resulting in the formation of apurinic/apyrimidinic (AP) sites and initiation of the carcinogenic process. In this study, we optimized a liquid chromatography-nanoelectrospray ionization-high-resolution tandem mass spectrometry method to analyze AP sites in buccal cell DNA of 35 nonsmokers, 30 smokers, and 30 e-cigarette users. AP sites in e-cigarette users (median 3.3 per 107 nts) were significantly lower than in smokers (median 5.7 per 107 nts) and nonsmokers (median 6.0 per 107 nts). AP sites in smokers were not significantly different from nonsmokers (p > 0.05). The e-cigarette vaporizing solvents propylene glycol and glycerin were tested and did not protect against AP site formation in in vitro control and carcinogen exposed rat liver homogenates. However, propylene glycol may inhibit bacteria in oral cells, resulting in reduced inflammation and related effects, and reduced AP site levels in e-cigarette user DNA. This is the first study to examine AP site formation in e-cigarette users and to evaluate AP sites in human oral cell DNA.
Bibliographical noteFunding Information:
This study was supported by grant number CA-203851 from the U.S. National Cancer Institute (NIH) and the Food and Drug Administration Center for Tobacco Products. The content is solely the responsibility of the authors and does not necessarily represent the views of the NIH or the Food and Drug Administration. Mass spectrometry was carried out in the Analytical Biochemistry Shared Resource of the Masonic Cancer Center, University of Minnesota, supported in part by Cancer Center Support Grant CA-077598. The authors thank Steven Carmella for help with coordination of the samples, Menglan Chen and Joyce Zhao for the measurements of urinary CEMA, Nicole Thomson from the Sharon E. Murphy laboratory in the Masonic Cancer Center for measurements of urinary cotinine and NNAL, Qiyuan Han from the Natalia Tretyakova laboratory in the Masonic Cancer Center for the determination of bacterial content in oral cells, Yingchun Zhao for the help with mass spectrometric method development, and Bob Carlson for editorial support.
© 2021 American Chemical Society.
PubMed: MeSH publication types
- Journal Article
- Research Support, N.I.H., Extramural
- Research Support, U.S. Gov't, P.H.S.