Identification of New Markers of Alcohol-Derived DNA Damage in Humans
Valeria Guidolin1,2, Erik S Carlson2, Andrea Carrà2
1Division of Environmental Health Sciences, University of Minnesota, Minneapolis, MN 55455, USA.
Abstract:
Alcohol consumption is a risk factor for the development of several cancers, including those of the head and neck and the esophagus. The underlying mechanisms of alcohol-induced carcinogenesis remain unclear; however, at these sites, alcohol-derived acetaldehyde seems to play a major role. By reacting with DNA, acetaldehyde generates covalent modifications (adducts) that can lead to mutations. Previous studies have shown a dose dependence between levels of a major acetaldehyde-derived DNA adduct and alcohol exposure in oral-cell DNA. The goal of this study was to optimize a mass spectrometry (MS)-based DNA adductomic approach to screen for all acetaldehyde-derived DNA adducts to more comprehensively characterize the genotoxic effects of acetaldehyde in humans. A high-resolution/-accurate-mass data-dependent constant-neutral-loss-MS3 methodology was developed to profile acetaldehyde-DNA adducts in purified DNA. This resulted in the identification of 22 DNA adducts. In addition to the expected N-ethyldeoxyguanosine (after NaBH3CN reduction), two previously unreported adducts showed prominent signals in the mass spectra. MSn fragmentation spectra and accurate mass were used to hypothesize the structure of the two new adducts, which were then identified as N-ethyldeoxyadenosine and N-ethyldeoxycytidine by comparison with synthesized standards. These adducts were quantified in DNA isolated from oral cells collected from volunteers exposed to alcohol, revealing a significant increase after the exposure. In addition, 17 of the adducts identified in vitro were detected in these samples confirming our ability to more comprehensively characterize the DNA damage deriving from alcohol exposures.
Insights
Alcohol-derived acetaldehyde causes DNA damage, increasing cancer risk. This study identified new acetaldehyde DNA adducts in human oral cells, improving our understanding of alcohol-induced genotoxicity.
Area of Science:
- Toxicology
- Molecular Biology
- Cancer Research
Background:
- Alcohol consumption is a known risk factor for head and neck and esophageal cancers.
- Acetaldehyde, a metabolite of alcohol, is implicated in alcohol-induced carcinogenesis through DNA adduct formation.
- Previous research linked acetaldehyde-DNA adducts to alcohol exposure, but a comprehensive analysis was lacking.
Purpose of the Study:
- To optimize a mass spectrometry (MS)-based DNA adductomic approach for comprehensive screening of acetaldehyde-DNA adducts.
- To characterize the genotoxic effects of acetaldehyde in human oral cells.
- To identify and quantify novel acetaldehyde-derived DNA adducts.
Main Methods:
- Development of a high-resolution/accurate-mass data-dependent constant-neutral-loss-MS3 methodology for profiling acetaldehyde-DNA adducts in purified DNA.
- Identification of 22 DNA adducts, including two previously unreported adducts (N-ethyldeoxyadenosine and N-ethyldeoxycytidine).
- Quantification of adducts in oral cell DNA from alcohol-exposed volunteers.
Main Results:
- The optimized MS3 method successfully identified 22 acetaldehyde-DNA adducts in vitro.
- Two novel adducts, N-ethyldeoxyadenosine and N-ethyldeoxycytidine, were identified and structurally confirmed.
- A significant increase in acetaldehyde-DNA adducts was observed in oral cells of volunteers after alcohol exposure.
- 17 in vitro identified adducts were detected in human oral cell DNA, validating the comprehensive approach.
Conclusions:
- The developed DNA adductomic approach enables comprehensive characterization of acetaldehyde-induced DNA damage.
- Novel acetaldehyde-DNA adducts were identified in human oral cells, contributing to understanding alcohol's genotoxicity.
- This research provides a more complete picture of the DNA damage resulting from alcohol consumption, relevant to cancer risk assessment.
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