Developmental cigarette smoke exposure: liver proteome profile alterations in low birth weight pups

Association Between Smoking and Molecular Subtypes of Colorectal Cancer

Background

Smoking is associated with colorectal cancer (CRC) risk. Previous studies suggested this association may be restricted to certain molecular subtypes of CRC, but large-scale comprehensive analysis is lacking.

Methods

A total of 9789 CRC cases and 11 231 controls of European ancestry from 11 observational studies were included. We harmonized smoking variables across studies and derived sex study-specific quartiles of pack-years of smoking for analysis. Four somatic colorectal tumor markers were assessed individually and in combination, including BRAF mutation, KRAS mutation, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status. A multinomial logistic regression analysis was used to assess the association between smoking and risk of CRC subtypes by molecular characteristics, adjusting for age, sex, and study. All statistical tests were 2-sided and adjusted for Bonferroni correction.

Results

Heavier smoking was associated with higher risk of CRC overall and stratified by individual markers (P trend < .001). The associations differed statistically significantly between all molecular subtypes, which was the most statistically significant for CIMP and BRAF. Compared with never-smokers, smokers in the fourth quartile of pack-years had a 90% higher risk of CIMP-positive CRC (odds ratio = 1.90, 95% confidence interval = 1.60 to 2.26) but only 35% higher risk for CIMP-negative CRC (odds ratio = 1.35, 95% confidence interval = 1.22 to 1.49; P difference = 2.1 x 10-6). The association was also stronger in tumors that were CIMP positive, MSI high, or KRAS wild type when combined (P difference < .001).

Conclusion

Smoking was associated with differential risk of CRC subtypes defined by molecular characteristics. Heavier smokers had particularly higher risk of CRC subtypes that were CIMP positive and MSI high in combination, suggesting that smoking may be involved in the development of colorectal tumors via the serrated pathway.

Neonatal nicotine exposure changes insulin status in fat depots: sex-related differences

Nicotine is the main psychoactive substance present in cigarette smoke that is transferred to the baby by breast milk. In rats, maternal nicotine exposure during breastfeeding induces obesogenesis and hormone dysfunctions in adult male offspring. As glucocorticoid (GC), insulin, and vitamin D change both adipogenesis and lipogenesis processes, we assessed parameters related to metabolism and action of these hormones in visceral and subcutaneous adipose tissues (VAT and SAT) of adult male and female rats in a model of neonatal nicotine exposure. At postnatal (PN) day 2, dams were kept with six pups (three per sex) and divided into nicotine and control groups for implantation of osmotic minipumps that released 6 mg/kg nicotine or saline, respectively. At PN180, fat mass, hormone levels, and protein contents of biomarkers of the GC activation and receptor (11beta-hydroxysteroid dehydrogenase type 1 and glucocorticoid receptor alpha), insulin signaling pathway [insulin receptor beta (IRβ), phosphorylated insulin receptor substrate 1, insulin receptor substrate 1 (IRS1), phosphorylated serine/threonine kinase (pAKT), serine/threonine kinase, glucose transporter type 4 (GLUT4)], and vitamin D activation and receptor (1α-hydroxylase and vitamin D receptor) were evaluated. While nicotine-exposed males showed increased fat mass, hypercorticosteronemia, hyperinsulinemia, and higher 25-hydroxyvitamin D, these alterations were not observed in nicotine-exposed females. Nicotine-exposed males only showed lower IRS1 in VAT, while the females had hyperglycemia, higher pAKT in VAT, while lower IRβ, IRS1, and GLUT4 in SAT. Parameters related to metabolism and action of GC and vitamin D were unaltered in both sexes. We evidence that exposure exclusively to nicotine during breastfeeding affects the hormone status and fat depots of the adult progeny in a sex-dependent manner.

The Effect of Smoking in the Cosmetic Surgery Population: Analysis of 129,007 Patients

Background

Smoking has been associated with several postoperative adverse outcomes across multiple surgical disciplines, but the literature is limited for aesthetic surgical procedures.

Objectives

To compare complication rates between smokers and nonsmokers undergoing common cosmetic procedures, identify specific cosmetic procedures where smoking increases the risk of complications, and evaluate smoking as an independent risk factor for major complications following aesthetic surgery.

Methods

A prospective cohort of patients undergoing cosmetic surgery between 2008 and 2013 was identified from the CosmetAssure database. Smoking was evaluated as a risk factor for major complications requiring emergency room visit, hospital admission, or reoperation within 30 days after surgery. Multivariate regression analysis was performed controlling for the effects of age, gender, body mass index, type of surgical facility, type of procedure, and combined procedures.

Results

Of the 129,007 patients, 10,621 (8.2%) were smokers. All procedures examined, except breast augmentation, were more frequently performed in the nonsmoker cohort. Overall major complications were similar between smokers and nonsmokers (2.0% vs 1.9%, P = 0.57). In univariate analysis, surgical site infections (0.6% vs 0.5%, P = 0.04) were significantly higher among smokers, but suspected venous thromboembolism (0.2% vs 0.1%, P = 0.01) was significantly higher among nonsmokers. Notably, smokers had a higher risk of major complications after body procedures (2.9% vs 1.0%, P = 0.01), as well as thigh lifts (23.8% vs 3.6%, P < 0.01) and male breast surgery (3.7% vs 1.4%, P = 0.03). In multivariate analysis, smoking was found to be an independent predictor of surgical site infections (relative risk 1.61, P < 0.01).

Conclusions

Smoking is an independent risk factor of major surgical site infections following aesthetic surgery. Body procedures, as well as thigh lifts and male breast surgery, have higher complication rates in smokers.

Level of Evidence 2

Metabolomic profiles of current cigarette smokers

Smoking-related biomarkers for lung cancer and other diseases are needed to enhance early detection strategies and to provide a science base for tobacco product regulation. An untargeted metabolomics approach by ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UHPLC-Q-TOF MS) totaling 957 assays was used in a novel experimental design where 105 current smokers smoked two cigarettes 1 h apart. Blood was collected immediately before and after each cigarette allowing for within-subject replication. Dynamic changes of the metabolomic profiles from smokers' four blood samples were observed and biomarkers affected by cigarette smoking were identified. Thirty-one metabolites were definitively shown to be affected by acute effect of cigarette smoking, uniquely including menthol-glucuronide, the reduction of glutamate, oleamide, and 13 glycerophospholipids. This first time identification of a menthol metabolite in smokers' blood serves as proof-of-principle for using metabolomics to identify new tobacco-exposure biomarkers, and also provides new opportunities in studying menthol-containing tobacco products in humans. Gender and race differences also were observed. Network analysis revealed 12 molecules involved in cancer, notably inhibition of cAMP. These novel tobacco-related biomarkers provide new insights to the effects of smoking which may be important in carcinogenesis but not previously linked with tobacco-related diseases. © 2016 Wiley Periodicals, Inc.

Menthol Smokers: Metabolomic Profiling and Smoking Behavior

BACKGROUND

The use of menthol in cigarettes and marketing is under consideration for regulation by the FDA. However, the effects of menthol on smoking behavior and carcinogen exposure have been inconclusive. We previously reported metabolomic profiling for cigarette smokers, and novelly identified a menthol-glucuronide (MG) as the most significant metabolite directly related to smoking. Here, MG is studied in relation to smoking behavior and metabolomic profiles.

METHODS

This is a cross-sectional study of 105 smokers who smoked two cigarettes in the laboratory one hour apart. Blood nicotine, MG, and exhaled carbon monoxide (CO) boosts were determined (the difference before and after smoking). Spearman correlation, χ2, and ANCOVA adjusted for gender, race, and cotinine levels for menthol smokers assessed the relationship of MG boost, smoking behavior, and metabolic profiles. Multivariate metabolite characterization using supervised partial least squares-discriminant analysis (PLS-DA) was carried out for the classification of metabolomics profiles.

RESULTS

MG boost was positively correlated with CO boost, nicotine boost, average puff volume, puff duration, and total smoke exposure. Classification using PLS-DA, MG was the top metabolite discriminating metabolome of menthol versus nonmenthol smokers. Among menthol smokers, 42 metabolites were significantly correlated with MG boost, which linked to cellular functions, such as of cell death, survival, and movement.

CONCLUSIONS

Plasma MG boost is a new smoking behavior biomarker that may provide novel information over self-reported use of menthol cigarettes by integrating different smoking measures for understanding smoking behavior and harm of menthol cigarettes.

IMPACT

These results provide insight into the biological effect of menthol smoking. Cancer Epidemiol Biomarkers Prev; 26(1); 51-60. ©2016 AACR.

Developmental cigarette smoke exposure II: Hepatic proteome profiles in 6 month old adult offspring

Utilizing a mouse model of 'active' developmental cigarette smoke exposure (CSE) [gestational day (GD) 1 through postnatal day (PD) 21] characterized by offspring low birth weight, the impact of developmental CSE on liver proteome profiles of adult offspring at 6 months of age was determined. Liver tissue was collected from Sham- and CSE-offspring for 2D-SDS-PAGE based proteome analysis with Partial Least Squares-Discriminant Analysis (PLS-DA). A similar study conducted at the cessation of exposure to cigarette smoke documented decreased gluconeogenesis coupled to oxidative stress in weanling offspring. In the current study, exposure throughout development to cigarette smoke resulted in impaired hepatic carbohydrate metabolism, decreased serum glucose levels, and increased gluconeogenic regulatory enzyme abundances during the fed-state coupled to decreased expression of SIRT1 as well as increased PEPCK and PGC1α expression. Together these findings indicate inappropriately timed gluconeogenesis that may reflect impaired insulin signaling in mature offspring exposed to 'active' developmental CSE.

Developmental cigarette smoke exposure II: Kidney proteome profile alterations in 6 month old adult offspring

Cigarette smoke exposure (CSE) during gestation and early development suppresses the growth trajectory in offspring. In prior studies utilizing a mouse model of 'active' developmental CSE (GD1-PD21), low birth weight induced by CSE persisted throughout the neonatal period and was present at the cessation of exposure at weaning with proportionally smaller kidney mass that was accompanied by impairment of carbohydrate metabolism. In the present study, littermates of those characterized in the prior study were maintained until 6 months of age at which time the impact of developmental CSE on the abundance of proteins associated with cellular metabolism in the kidney was examined. Kidney protein abundances were examined by 2D-SDS-PAGE based proteome profiling with statistical analysis by Partial Least Squares-Discriminant Analysis. Key findings of this study include a persistence of impact of developmental CSE past the original exposure period on the nucleic acid and carbohydrate metabolism networks and oxidant scavenging pathways.

Developmental cigarette smoke exposure II: Hippocampus proteome and metabolome profiles in adult offspring

Exposure to cigarette smoke during development is linked to neurodevelopmental delays and cognitive impairment including impulsivity, attention deficit disorder, and lower IQ. Utilizing a murine experimental model of "active" inhalation exposure to cigarette smoke spanning the entirety of gestation and through human third trimester equivalent hippocampal development [gestation day 1 (GD1) through postnatal day 21 (PD21)], we examined hippocampus proteome and metabolome alterations present at a time during which developmental cigarette smoke exposure (CSE)-induced behavioral and cognitive impairments are evident in adult animals from this model system. At six month of age, carbohydrate metabolism and lipid content in the hippocampus of adult offspring remained impacted by prior exposure to cigarette smoke during the critical period of hippocampal ontogenesis indicating limited glycolysis. These findings indicate developmental CSE-induced systemic glucose availability may limit both organism growth and developmental trajectory, including the capacity for learning and memory.

Mainstream smoke and sidestream smoke affect the cardiac differentiation of mouse embryonic stem cells discriminately

Epidemiology studies suggest that maternal smoking and passive smoking have strongly resulted in the occurrence of congenital heart defects (CHD) in offspring. Cigarette smoke (CS) can be divided into mainstream smoke (MS) and sidestream smoke (SS); CS chemistry study indicates that significant differences exist in the composition of MS and SS. Therefore, MS and SS were suspected to process toxicity dissimilarly. However, much less was known about the difference in the developmental effects induced by MS and SS. In the current study, heart development was mimicked by mouse embryonic stem cells (ESCs) differentiation. After MS and SS exposure, by tracing the bone morphogenetic protein (BMP)-Smad4 signalling pathway, interruption of downstream gene expression was observed, including Gata4, Mef2c and Nkx2.5, as well as myosin heavy chain and myosin light chain. Specifically, SS caused inhibition of Gata4 expression, even at non-cytotoxic concentration. Further, SS-induced hypoacetylation in promoter regions of Gata4 reflected the orchestration of CS-gene modulation-epigenetic regulation. Even though SS induced apoptosis in ESC-derived cardiomyocytes, the partial clearance in cells with down-regulated Gata4 caused these cells to survive and undergo further differentiation, which laid potential risk for abnormal heart development. These data uncovered the difference between MS and SS on heart development preliminarily.

A simple and rapid method for standard preparation of gas phase extract of cigarette smoke

Cigarette smoke consists of tar and gas phase: the latter is toxicologically important because it can pass through lung alveolar epithelium to enter the circulation. Here we attempt to establish a standard method for preparation of gas phase extract of cigarette smoke (CSE). CSE was prepared by continuously sucking cigarette smoke through a Cambridge filter to remove tar, followed by bubbling it into phosphate-buffered saline (PBS). An increase in dry weight of the filter was defined as tar weight. Characteristically, concentrations of CSEs were represented as virtual tar concentrations, assuming that tar on the filter was dissolved in PBS. CSEs prepared from smaller numbers of cigarettes (original tar concentrations ≤ 15 mg/ml) showed similar concentration-response curves for cytotoxicity versus virtual tar concentrations, but with CSEs from larger numbers (tar ≥ 20 mg/ml), the curves were shifted rightward. Accordingly, the cytotoxic activity was detected in PBS of the second reservoir downstream of the first one with larger numbers of cigarettes. CSEs prepared from various cigarette brands showed comparable concentration-response curves for cytotoxicity. Two types of CSEs prepared by continuous and puff smoking protocols were similar regarding concentration-response curves for cytotoxicity, pharmacology of their cytotoxicity, and concentrations of cytotoxic compounds. These data show that concentrations of CSEs expressed by virtual tar concentrations can be a reference value to normalize their cytotoxicity, irrespective of numbers of combusted cigarettes, cigarette brands and smoking protocols, if original tar concentrations are ≤15 mg/ml.

Pathophysiology of tobacco smoke exposure: recent insights from comparative and redox proteomics

First-hand and second-hand tobacco smoke are causally linked to a huge number of deaths and are responsible for a broad spectrum of pathologies such as cancer, cardiovascular, respiratory, and eye diseases as well as adverse effects on female reproductive function. Cigarette smoke is a complex mixture of thousands of different chemical species, which exert their negative effects on macromolecules and biochemical pathways, both directly and indirectly. Many compounds can act as oxidants, pro-inflammatory agents, carcinogens, or a combination of these. The redox behavior of cigarette smoke has many implications for smoke related diseases. Reactive oxygen and nitrogen species (both radicals and non-radicals), reactive carbonyl compounds, and other species may induce oxidative damage in almost all the biological macromolecules, compromising their structure and/or function. Different quantitative and redox proteomic approaches have been applied in vitro and in vivo to evaluate, respectively, changes in protein expression and specific oxidative protein modifications induced by exposure to cigarette smoke and are overviewed in this review. Many gel-based and gel-free proteomic techniques have already been used successfully to obtain clues about smoke effects on different proteins in cell cultures, animal models, and humans. The further implementation with other sensitive screening techniques could be useful to integrate the comprehension of cigarette smoke effects on human health. In particular, the redox proteomic approach may also help identify biomarkers of exposure to tobacco smoke useful for preventing these effects or potentially predictive of the onset and/or progression of smoking-induced diseases as well as potential targets for therapeutic strategies.

Developmental cigarette smoke exposure: hippocampus proteome and metabolome profiles in low birth weight pups

Exposure to cigarette smoke during development is linked to neurodevelopmental delays and cognitive impairment including impulsivity, attention deficit disorder, and lower IQ. However, brain region specific biomolecular alterations induced by developmental cigarette smoke exposure (CSE) remain largely unexplored. In the current molecular phenotyping study, a mouse model of 'active' developmental CSE (serum cotinine > 50 ng/mL) spanning pre-implantation through third trimester-equivalent brain development (gestational day (GD) 1 through postnatal day (PD) 21) was utilized. Hippocampus tissue collected at the time of cessation of exposure was processed for gel-based proteomic and non-targeted metabolomic profiling with partial least squares-discriminant analysis (PLS-DA) for selection of features of interest. Ingenuity pathway analysis was utilized to identify candidate molecular and metabolic pathways impacted within the hippocampus. CSE impacted glycolysis, oxidative phosphorylation, fatty acid metabolism, and neurodevelopment pathways within the developing hippocampus.

Lilium lancifolium Thunb. extract attenuates pulmonary inflammation and air space enlargement in a cigarette smoke-exposed mouse model

ETHNOPHARMACOLOGICAL RELEVANCE

Lilium lancifolium Thunb. (Liliaceae) has long been used as a traditional medicine in Korea and China to treat bronchitis, pneumonia, and other pulmonary ailments.

AIM OF THE STUDY

Cigarette smoke (CS) is a major risk factor for the development of pulmonary inflammatory response; it also triggers pulmonary alveoli enlargement. In the present study, we investigate the effects of Lilium lancifolium Thunb. root extract on pulmonary inflammatory responses in a CS-exposed mouse model.

MATERIALS AND METHODS

Water extract of Lilium lancifolium Thunb. root was fed to C57BL/6 mice prior CS exposure every day for 3 weeks. The numbers of macrophages and neutrophils in bronchoalveolar lavage fluid (BALF) were counted. The relative inflammatory factors, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-1 beta (IL-1β), monocyte chemotactic protein-1 (MCP-1), and matrix metalloproteinase-12 (MMP-12) were measured by real-time PCR, ELISA, or Western blot analysis. The average alveoli size was determined by lung histology.

RESULTS

Lilium lancifolium Thunb. root extract was found to significantly inhibit the numbers of macrophages and neutrophils in BALF due to CS exposure. Lilium lancifolium Thunb. root extract also reduced the protein secretion levels of TNF-α, IL-6, IL-1β, and MCP-1 in BALF and the RNA expression levels of TNF-α, IL-6, IL-1β, MCP-1, and MMP-12 in lung tissue compared with mice only exposed to CS. Moreover, MMP-12 in serum was down regulated in Lilium lancifolium Thunb. root extract treated mice compared with CS-exposed mice. Finally, a morphometric analysis of the lungs of Lilium lancifolium Thunb. root extract treated mice demonstrated a significant reduction in airspace size compared to mice only exposed to CS.

CONCLUSION

Our results show that Lilium lancifolium Thunb. root extract reduces lung inflammation and airspace enlargement in a CS-exposed mouse model. These data indicate that Lilium lancifolium Thunb. root extract is a therapeutic candidate for pulmonary inflammation and emphysema caused by CS.

A prospective study of duration of smoking cessation and colorectal cancer risk by epigenetics-related tumor classification

The effect of duration of cigarette smoking cessation on colorectal cancer risk by molecular subtypes remains unclear. Using duplication-method Cox proportional-hazards regression analyses, we examined associations between duration of smoking cessation and colorectal cancer risk according to status of CpG island methylator phenotype (CIMP), microsatellite instability, v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutation, or DNA methyltransferase-3B (DNMT3B) expression. Follow-up of 134,204 individuals in 2 US nationwide prospective cohorts (Nurses' Health Study (1980-2008) and Health Professionals Follow-up Study (1986-2008)) resulted in 1,260 incident rectal and colon cancers with available molecular data. Compared with current smoking, 10-19, 20-39, and ≥40 years of smoking cessation were associated with a lower risk of CIMP-high colorectal cancer, with multivariate hazard ratios (95% confidence intervals) of 0.53 (0.29, 0.95), 0.52 (0.32, 0.85), and 0.50 (0.27, 0.94), respectively (Ptrend = 0.001), but not with the risk of CIMP-low/CIMP-negative cancer (Ptrend = 0.25) (Pheterogeneity = 0.02, between CIMP-high and CIMP-low/CIMP-negative cancer risks). Differential associations between smoking cessation and cancer risks by microsatellite instability (Pheterogeneity = 0.02), DNMT3B expression (Pheterogeneity = 0.03), and BRAF (Pheterogeneity = 0.10) status appeared to be driven by the associations of CIMP-high cancer with microsatellite instability-high, DNMT3B-positive, and BRAF-mutated cancers. These molecular pathological epidemiology data suggest a protective effect of smoking cessation on a DNA methylation-related carcinogenesis pathway leading to CIMP-high colorectal cancer.

Prenatal alcohol exposure alters the cerebral cortex proteome in weanling rats

Maternal consumption of alcohol during pregnancy impairs neurodevelopment in offspring. Utilizing a rodent model of continuous moderate dose alcohol exposure throughout gestation [gestation day 1 (GD1)-GD22; BAC ~70 mg/dL], the impact of developmental alcohol exposure on juvenile cerebral cortex protein abundances was determined. At weaning, cerebral cortex tissue was collected from pups for 2D SDS-PAGE based proteome analysis with statistical analysis by Partial Least Squares-Discriminant Analysis (PLS-DA). Gestational alcohol exposure increased the abundance of post-translationally modified forms of cytoskeletal proteins and the abundance of proteins within the small molecule biochemistry (includes glucose metabolism) pathway and proteosome processing pathways though ubiquitin conjugating enzymes and chaperones were decreased in abundance. In weanling offspring exposed prenatally to alcohol, alterations in cytoskeletal protein post-translational modifications were noted. Increased abundance of proteins from the small molecule biochemistry pathway, which includes glucose metabolism, and proteosome processing pathways were also noted. Decreased abundances of ubiquitin conjugating enzyme and chaperone protein were noted in the cerebral cortex of these offspring.

Developmental cigarette smoke exposure: kidney proteome profile alterations in low birth weight pups

The Brenner hypothesis states that a congenital reduction in nephron number predisposes to adult-onset hypertension and renal failure. The reduction in nephron number induced by proportionally smaller kidney mass may predispose offspring to glomerular hyperfiltration with maturity onset obesity. Developmental cigarette smoke exposure (CSE) results in intrauterine growth retardation with a predisposition to obesity and cardiovascular disease at maturity. Utilizing a mouse model of 'active' developmental CSE (gestational day [GD] 1-postnatal day [PD] 21; cotinine>50 ng/mL) characterized by persistently smaller offspring with proportionally decreased kidney mass, the present study examined the impact of developmental CSE on the abundance of proteins associated with cellular metabolism in the kidney. Following cessation of CSE on PD21, kidney tissue was collected from CSE and Sham exposed pups for 2D-SDS-PAGE based proteome profiling with statistical analysis by partial least squares-discriminant analysis (PLS-DA) with affected molecular pathways identified by ingenuity pathway analysis. Proteins whose expression in the kidney were affected by developmental CSE belonged to the inflammatory disease, cell to cell signaling/interaction, lipid metabolism, small molecule biochemistry, cell cycle, respiratory disease, nucleic acid and carbohydrate metabolism networks. The present findings indicate that developmental CSE alters the kidney proteome. The companion paper details the liver proteome alterations in the same offspring.