Recent Studies on DNA Adducts Resulting from Human Exposure to Tobacco Smoke.
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SUBMITTER: Ma B
PROVIDER: S-EPMC6468371 | biostudies-literature | 2019 Mar
REPOSITORIES: biostudies-literature
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Recent Studies on DNA Adducts Resulting from Human Exposure to Tobacco Smoke.
Ma Bin B Stepanov Irina I Hecht Stephen S SS
Toxics 20190319 1
DNA adducts are believed to play a central role in the induction of cancer in cigarette smokers and are proposed as being potential biomarkers of cancer risk. We have summarized research conducted since 2012 on DNA adduct formation in smokers. A variety of DNA adducts derived from various classes of carcinogens, including aromatic amines, polycyclic aromatic hydrocarbons, tobacco-specific nitrosamines, alkylating agents, aldehydes, volatile carcinogens, as well as oxidative damage have been repo ...[more]
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Project description:Smoking is the leading preventable disease worldwide and passive smoking is estimated to be the cause of about 1.0% of worldwide mortality. The determination of tobacco smoke biomarkers in human biological matrices is key to assess the health effects related to the exposure to environmental tobacco smoke. The biomonitoring of cotinine, the main nicotine metabolite, in human biofluids-including urine, serum or saliva-has been extensively used to assess this exposure. However, the simultaneous determination of cotinine together with other tobacco biomarkers and the selection of alternative biological matrices, such as hair, skin or exhaled breath, would enable a better characterization of the kind and extent of tobacco exposure. This review aims to perform a critical analysis of the up-to-date literature focused on the simultaneous determination of multiple tobacco smoke biomarkers studied in different biological matrices, due to the exposure to secondhand smoke (SHS) and thirdhand smoke (THS). Target biomarkers included both tobacco-specific biomarkers-nicotine and tobacco specific nitrosamine biomarkers-and tobacco-related biomarkers, such as those from polycyclic aromatic hydrocarbons, volatile organic compounds, metals and carbon monoxide. To conclude, we discuss the suitability of determining multiple biomarkers through several relevant examples of SHS and THS exposure.
| S-EPMC6313747 | biostudies-literature
Project description:Prenatal exposure to tobacco smoke increases the risk for diseases later in the child's life that may be mediated through alterations in DNA methylation.To demonstrate that differences in DNA methylation patterns occur in children exposed to tobacco smoke and that variation in detoxification genes may alter these associations.Methylation of DNA repetitive elements, LINE1 and AluYb8, was measured using bisulfite conversion and pyrosequencing in buccal cells of 348 children participating in the Children's Health Study. Gene-specific CpG methylation differences associated with smoke exposure were screened in 272 participants in the Children's Health Study children using an Illumina GoldenGate panel. CpG loci that demonstrated a statistically significant difference in methylation were validated by pyrosequencing. Estimates were standardized across loci using a Z score to enable cross-comparison of results.DNA methylation patterns were associated with in utero exposure to maternal smoking. Exposed children had significantly lower methylation of AluYb8 (beta, -0.31; P = 0.03). Differences in smoking-related effects on LINE1 methylation were observed in children with the common GSTM1 null genotype. Differential methylation of CpG loci in eight genes was identified through the screen. Two genes, AXL and PTPRO, were validated by pyrosequencing and showed significant increases in methylation of 0.37 (P = 0.005) and 0.34 (P = 0.02) in exposed children. The associations with maternal smoking varied by a common GSTP1 haplotype.Life-long effects of in utero exposures may be mediated through alterations in DNA methylation. Variants in detoxification genes may modulate the effects of in utero exposure through epigenetic mechanisms.
| S-EPMC2742762 | biostudies-literature
Project description:BackgroundSmoking while pregnant is associated with a myriad of negative health outcomes in the child. Some of the detrimental effects may be due to epigenetic modifications, although few studies have investigated this hypothesis in detail.ObjectivesTo characterize site-specific epigenetic modifications conferred by prenatal smoking exposure within asthmatic children.MethodsUsing Illumina HumanMethylation27 microarrays, we estimated the degree of methylation at 27,578 distinct DNA sequences located primarily in gene promoters using whole blood DNA samples from the Childhood Asthma Management Program (CAMP) subset of Asthma BRIDGE childhood asthmatics (n?=?527) ages 5-12 with prenatal smoking exposure data available. Using beta-regression, we screened loci for differential methylation related to prenatal smoke exposure, adjusting for gender, age and clinical site, and accounting for multiple comparisons by FDR.ResultsOf 27,578 loci evaluated, 22,131 (80%) passed quality control assessment and were analyzed. Sixty-five children (12%) had a history of prenatal smoke exposure. At an FDR of 0.05, we identified 19 CpG loci significantly associated with prenatal smoke, of which two replicated in two independent populations. Exposure was associated with a 2% increase in mean CpG methylation in FRMD4A (p?=?0.01) and Cllorf52 (p?=?0.001) compared to no exposure. Four additional genes, XPNPEP1, PPEF2, SMPD3 and CRYGN, were nominally associated in at least one replication group.ConclusionsThese data suggest that prenatal exposure to tobacco smoke is associated with reproducible epigenetic changes that persist well into childhood. However, the biological significance of these altered loci remains unknown.
| S-EPMC4070909 | biostudies-literature
Project description:BackgroundMaternal smoking during pregnancy is a risk factor for chronic disease later in life and has been associated with variability of DNA methylation at specific cytosine-phosphate-guanine (CpG) loci. We assessed the role of DNA methylation as a potential mediator of adverse effects of in utero tobacco smoke exposures on asthma outcomes in Latino children from the US mainland and Puerto Rico.MethodsRelationships between self-reported exposure and DNA methylation at CpG loci previously reported to be associated with maternal smoking were assessed in a subsample consisting of 572 children aged 8-21 years (310 cases with asthma, 262 healthy controls), sampled from a larger asthma case-control study. Subsequently, we assessed associations between top loci and asthma-related outcomes, followed by mediation analysis for loci for which associations with outcomes were observed.ResultsSelf-reported maternal smoking was associated with a -1.5% (95% confidence interval (CI) = -2.4%, -0.6%) lower methylation at CpG locus cg05575921 on the AHRR gene; a 1% increase in DNA methylation at the same locus resulted in an odds ratio (OR) of 0.90 (95% CI = 0.83, 0.96) for the odds of asthma. The OR for the indirect effect of maternal smoking on asthma mediated through methylation at the cg05575921 locus was 1.18 (95% CI = 1.07, 1.68), compared to the OR for the total effect of exposure in the parent study of 1.48 (95% CI = 1.03, 2.11).ConclusionsOur findings suggest potential mediation by DNA methylation in the association between maternal smoking during pregnancy and asthma status.
| S-EPMC6571182 | biostudies-literature
Project description:Cigarette smoking damages the extracellular matrix in a variety of locations, leading to atherosclerotic plaque instability and emphysematous lung destruction, but the underlying mechanisms remain poorly understood. Here, we sought to determine whether exposure of human macrophages, a key participant in extracellular matrix damage, to tobacco smoke extract (TSE) induces the release of microvesicles (MVs; or microparticles) with proteolytic activity; the major proteases involved; and the cellular mechanisms that might mediate their generation. We found that MVs released from TSE-exposed macrophages carry substantial gelatinolytic and collagenolytic activities that surprisingly can be predominantly attributed to a single transmembrane protease of the matrix metalloproteinase (MMP) superfamily (namely, MMP14). Flow cytometric counts revealed that exposure of human macrophages to TSE for 20 hours more than quadrupled their production of MMP14-positive MVs (control, 1112 ± 231; TSE-induced, 5823 ± 2192 MMP14-positive MVs/?L of conditioned medium; means ± SEM; n = 6; P < 0.01). Our results indicate that the production of these MVs by human macrophages relies on a series of regulated steps that include activation of two mitogen-activated protein kinases (MAPKs, i.e., the Jun N-terminal kinase and p38 MAPK), and then MAPK-dependent induction and maturation of cellular MMP14, a remarkable accumulation of MMP14 into nascent plasma membrane blebs, and finally caspase- and MAPK-dependent apoptosis and apoptotic microvesicle generation. Proteolytically active MVs induced by tobacco smoke may be novel mediators of clinical important matrix destruction in smokers.
| S-EPMC3644720 | biostudies-literature
Project description:Introduction:Cigarette smoking is inversely associated with DNA methylation of the aryl hydrocarbon receptor repressor (AHRR; cg05575921). However, the association between secondhand tobacco smoke (SHS) exposure and AHRR methylation is unknown. Methods:DNA methylation of AHRR cg05575921 in CD14+ monocyte samples, from 495 never-smokers and 411 former smokers (having quit smoking ?15 years) from the Multi-Ethnic Study of Atherosclerosis (MESA), was cross-sectionally compared with concomitantly ascertained self-reported SHS exposure, urine cotinine concentrations, and estimates of air pollutants at participants' homes. Linear regression was used to test for associations, and covariates included age, sex, race, education, study site, and previous smoking exposure (smoking status, time since quitting, and pack-years). Results:Recent indoor SHS exposure (hours per week) was inversely associated with cg05575921 methylation (? ± SE = -0.009 ± 0.003, p = .007). The inverse effect direction was consistent (but did not reach significance) in the majority of stratified analyses (by smoking status, sex, and race). Categorical analysis revealed high levels of recent SHS exposure (?10 hours per week) inversely associated with cg05575921 methylation (? ± SE = -0.28 ± 0.09, p = .003), which remained significant (p < .05) in the majority of stratified analyses. cg05575921 methylation did not significantly (p < .05) associate with low to moderate levels of recent SHS exposure (1-9 hours per week), urine cotinine concentrations, years spent living with people smoking, years spent indoors (not at home) with people smoking, or estimated levels of air pollutants. Conclusions:High levels of recent indoor SHS exposure may be inversely associated with DNA methylation of AHRR in human monocytes. Implications:DNA methylation is a biochemical alteration that can occur in response to cigarette smoking; however, little is known about the effect of SHS on human DNA methylation. In the present study, we evaluated the association between SHS exposure and DNA methylation in human monocytes, at a site (AHRR cg05575921) known to have methylation inversely associated with current and former cigarette smoking compared to never smoking. Results from this study suggest high levels of recent SHS exposure inversely associate with DNA methylation of AHRR cg05575921 in monocytes from nonsmokers, albeit with weaker effects than active cigarette smoking.
| S-EPMC6075517 | biostudies-literature
Project description:BackgroundAirports may represent significant sources of secondhand smoke (SHS) exposure for both travelers and employees. While previously common smoking rooms have largely disappeared from US airports, smoking continues to occur outdoors at terminal entrances. SHS may be especially high at arrival areas, since they oftentimes are partially enclosed by overhead departures, creating stagnant microenvironments. This study assessed particulate matter <2.5 microns in diameter (PM2.5), a common surrogate for SHS, at airport terminal locations to evaluate both outdoor exposure risk and possible indoor drift of SHS from outdoor sources.MethodsA convenience sample of nine airport terminal arrival areas in the US state of Florida was surveyed between February and July 2018. PM2.5 levels were assessed outdoors and indoors at terminal entrances and at control areas far into terminal interiors. We also examined the impact of smoking location on SHS exposure by correlating cigarette and passing vehicle counts with PM2.5 levels at terminals with contrasting proximity of designated smoking locations to terminal entrances.ResultsAlthough outdoor PM2.5 levels (mean 17.9, SD 6.1 µg/m3) were significantly higher than indoors (p < 0.001), there was no difference between indoor areas directly inside terminal entrances and areas much further interior (mean 8.8, SD 2.6 vs mean 8.5, SD 3.0 µg/m3, p=0.49). However, when smoking areas were in close proximity to terminal entrances, the number of lit cigarettes and vehicular traffic per minute predicted 70% of the variance of PM2.5 levels (p < 0.001), which was attributable mostly to the cigarette number (β = 0.83; 95% CI (0.55 to 1.11); p < 0.001). This effect was not observed at smoking areas further away.ConclusionPM2.5 data did not suggest indoor drift from outside smoking. Nevertheless, absolute exposure outdoors was high and correlated with the location of designated smoking areas. Further studies are needed to examine the effect of microclimate formation on exposure risk.
| S-EPMC6377972 | biostudies-literature
Project description:ObjectiveMany children experience tobacco smoke exposure (TSE) and parents may take preventive measures to reduce TSE. The study goal is to assess if these strategies are associated with lower cotinine values, an objective biological measure of TSE.MethodsFamilies admitted to Children's Hospital Colorado from 2014 to 2018 who screened positive for TSE were invited to participate in a tobacco smoking cessation/reduction program. Caregivers were consented and asked about demographics, beliefs around smoking, and strategies to reduce TSE. Child urine samples were collected, tested for cotinine levels, and analyzed using geometric means. Bivariable comparisons and multivariable linear regression were completed using SAS v9.4 (SAS Institute, Cary, NC).ResultsTwo hundred thirteen children (81.4%) are included in this analysis. The median ages of children and parents were 4 and 32 years respectively. Fifty-seven percent of children were male, 36% were Hispanic, and 55% were white. Fifty-six percent of parents had at least some college education and 69% had an annual income less than $50K. The median daily cigarettes smoked per day were 10. Eighty-eight percent reported using at least 1 type of protective measure to prevent TSE and 90% believed they protect other household members from TSE. None of the strategies had a significant relationship with lower cotinine levels on bivariable or multivariable analyses.ConclusionsParental strategies to decrease TSE did not result in lower cotinine levels. Many measures are not evidence-based and do not protect children. Parent's clothing and homes may create a reservoir for nicotine. Education should focus on exposure elimination and cessation rather than protective measures.
| S-EPMC7442659 | biostudies-literature
Project description:BackgroundMaternal tobacco smoke exposure has been associated with altered DNA methylation. However, previous studies largely used methylation arrays, which cover a small fraction of CpGs, and focused on whole cord blood.ObjectivesThe current study examined the impact of in utero exposure to maternal tobacco smoke on the cord blood [Formula: see text] DNA methylome.MethodsThe methylomes of 20 Hispanic white newborns ([Formula: see text] exposed to any maternal tobacco smoke in pregnancy; [Formula: see text] unexposed) from the Maternal and Child Health Study (MACHS) were profiled by whole-genome bisulfite sequencing (median coverage: [Formula: see text]). Statistical analyses were conducted using the Regression Analysis of Differential Methylation (RADMeth) program because it performs well on low-coverage data (minimizes false positives and negatives).ResultsWe found that 10,381 CpGs were differentially methylated by tobacco smoke exposure [neighbor-adjusted p-values that are additionally corrected for multiple testing based on the Benjamini-Hochberg method for controlling the false discovery rate (FDR) [Formula: see text]]. From these CpGs, RADMeth identified 557 differentially methylated regions (DMRs) that were overrepresented ([Formula: see text]) in important regulatory regions, including enhancers. Of nine DMRs that could be queried in a reduced representation bisulfite sequencing (RRBS) study of adult [Formula: see text] cells ([Formula: see text] smokers; [Formula: see text] nonsmokers), four replicated ([Formula: see text]). Additionally, a CpG in the promoter of SLC7A8 (percent methylation difference: [Formula: see text] comparing exposed to unexposed) replicated ([Formula: see text]) in an EPIC (Illumina) array study of cord blood [Formula: see text] cells ([Formula: see text] exposed to sustained maternal tobacco smoke; [Formula: see text] unexposed) and in a study of adult [Formula: see text] cells across two platforms (EPIC: [Formula: see text] smokers; [Formula: see text] nonsmokers; 450K: [Formula: see text] smokers; [Formula: see text] nonsmokers).ConclusionsMaternal tobacco smoke exposure in pregnancy is associated with cord blood [Formula: see text] DNA methylation in key regulatory regions, including enhancers. While we used a method that performs well on low-coverage data, we cannot exclude the possibility that some results may be false positives. However, we identified a differentially methylated CpG in amino acid transporter SLC7A8 that is highly reproducible, which may be sensitive to cigarette smoke in both cord blood and adult [Formula: see text] cells. https://doi.org/10.1289/EHP3398.
| S-EPMC6785223 | biostudies-literature
Project description:ObjectiveThis prospective clinical study comparatively investigated the effects of tobacco smoking on global methylation and hydroxymethylation in oral epithelial cells.MethodsBuccal cells from the inside of the cheeks were collected from 47 individuals, including smokers, former smokers, and never smokers. DNA was extracted using dedicated kits. Methylated and hydroxymethylated DNA fractions were measured using assays similar to enzyme-linked immunosorbent assays. The levels of methylation and hydroxymethylation were compared among groups using unpaired two-tailed t-tests or the Mann-Whitney U test; P < 0.05 was considered statistically significant.ResultsThere was no statistically significant difference in the average number of cigarettes between smoker and former smoker groups. Although methylation levels were lower for smokers (3.1%) and former smokers (2.16%), compared with never smokers (4.16%), these differences were not statistically significant. There was a two-fold increase in hydroxymethylation level in never smokers, compared with smokers.ConclusionsOur findings suggest that smoking leads to global reductions in both methylation and hydroxymethylation levels in oral epithelial cells in a manner influenced by the intensity and length of exposure to tobacco smoke.
| S-EPMC7503033 | biostudies-literature