Analysis of Acrolein-Derived 1,N²-Propanodeoxyguanosine Adducts in Human Lung DNA from Smokers and Nonsmokers

Abstract

Acrolein, the simplest α, β-unsaturated aldehyde, is present in relatively large quantities in cigarette smoke and several studies have raised the possibility of it being a major etiological agent for smoking related lung cancer. Acrolein reacts directly with DNA to form primarily Acr-dGuo adducts, which serve as important biomarkers for the assessment of exposure to acrolein and its potential role in smoking related lung cancer. In this study, we developed an ultra-sensitive and low-artifact method using liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry (LC-NSI-HRMS/MS) to quantitate Acr-dGuo adducts in normal lung tissue DNA obtained at surgery from lung cancer patients who never smoked and from those who continued smoking until surgery, as confirmed by urinary total cotinine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). This provides a direct comparison of Acr-dGuo levels in human lung tissue as a result of cigarette smoking versus other etiological causes. There was no significant difference between the total Acr-dGuo levels in smokers (28.5 ± 14.9 adducts/10 9 nucleotides) and non-smokers (25.0 ± 10.7 adducts/10 9 nucleotides), suggesting rapid removal of acrolein by glutathione conjugation and other detoxification mechanisms. Our results do not support the hypothesis that acrolein is a major etiological agent for cigarette smoking related DNA damage.

Recent Studies on DNA Adducts Resulting from Human Exposure to Tobacco Smoke

“…In the same study, γ-OH-Acr-dG was also detected in noncancerous lung tissues obtained from lung cancer patients with higher levels in smokers ( n = 41) compared to nonsmokers ( n = 13) [53]. Compared to our study of γ-OH-Acr-dG in human lung tissues [94], the levels obtained by Weng et al were 10–20 times higher, suggesting possible artifactual formation of γ-OH-Acr-dG, which was not investigated in their study. Similarly, a drastic difference of BPDE-dG levels was also observed between our study and the study by Weng et al The average level of BPDE-dG in smokers’ lung in our study was ~3 adducts per 10 11 nucleotides [32], while the average level in their study was ~1000 times higher [53].…”

“…The levels of α-OH-Acr-dG averaged 0.86 ± 0.27 and 1.0 ± 0.47 adducts per 10 8 nucleotides in smokers and nonsmokers, respectively, and the levels of γ-OH-Acr-dG averaged 2.0 ± 1.4 and 1.5 ± 0.64 adducts per 10 8 nucleotides in smokers and nonsmokers, respectively. There was no significant difference in the levels of α-OH-Acr-dG or γ-OH-Acr-dG between smokers and nonsmokers [94]. While the sample size was relatively small, our results indicate that acrolein is not a major etiological agent for cigarette smoking related DNA damage.…”

“…However, the smoking status of some subjects in that study was unknown, which made it difficult to interpret the role of smoking in the adduct formation. Recently, we have developed a new ultrasensitive LC-NSI-HRMS/MS method for the analysis of Acr-dG adducts in human lung DNA samples [94]. In addition to improved sensitivity, we also managed to lower the levels of artifactual formation of adducts during sample preparation and minimized the interference of artifactually formed DNA adducts in quantitation.…”

The safety evaluation of food flavoring substances: the role of genotoxicity studies

“…DNA adducts. DNA adduct studies have been conducted for only a small number of flavoring substances and potential metabolites, including formaldehyde, acetaldehyde, the a,b-unsaturated aldehydes acrolein, crotonaldehyde, and related compounds (Wang et al 2000;Hecht et al 2001;Hecht et al 2011;Yang et al 2019), 2-hexenal and trans, trans-2,4-hexadienal (Frankel et al 1987;Eder et al 1993;Eisenbrand et al 1995;NTP 2003); estragole (Ishii et al 2011;Paini et al 2012;Ding et al 2015), and methyl eugenol (Phillips et al 1984;Herrmann et al 2013;Williams et al 2013;Herrmann et al 2014;Monien et al 2015;Tremmel et al 2017). Most flavoring substances have chemical structures that make them unlikely candidates for DNA adduct formation (e.g.…”

“…DNA adducts can be detected at extremely low levels, e.g. the reported limit of detection (LOD) is as low as 1 adduct per 10 11 nucleotides and the limit of quantitation (LOQ) is as low as 5 adducts per 10 11 nucleotides by LC/MS (Zhang et al 2006;Monien et al 2015;Villalta et al 2017;Yang et al 2019) and is even lower by accelerator MS (Hummel et al 2018;Madeen et al 2019). Therefore, it is critical to evaluate whether the level of DNA adducts detected is biologically significant.…”