Alcohol and genetic polymorphisms: effect on risk of alcohol-related cancer

Prognostic value of alcohol dehydrogenase mRNA expression in gastric cancer

Previous studies have reported that alcohol dehydrogenase (ADH) isoenzymes possess diagnostic value in gastric cancer (GC). However, the prognostic value of ADH isoenzymes in GC remains unclear. The aim of the present study was to identify the prognostic value of ADH genes in patients with GC. The prognostic value of ADH genes was investigated in patients with GC using the Kaplan-Meier plotter tool. Kaplan-Meier plots were used to assess the difference between groups of patients with GC with different prognoses. Hazard ratios (HR) and 95% confidence intervals (CI) were used to assess the relative risk of GC survival. Overall, 593 patients with GC and 7 ADH genes were included in the survival analysis. High expression of ADH 1A (class 1), α polypeptide (ADH1A; log-rank P=0.043; HR=0.79; 95% CI: 0.64–0.99), ADH 1B (class 1), β polypeptide (ADH1B; log-rank P=1.9×10⁻⁰⁵; HR=0.65; 95% CI: 0.53–0.79) and ADH 5 (class III), χ polypeptide (ADH5; log-rank P=0.0011; HR=0.73; 95% CI: 0.6–0.88) resulted in a significantly decreased risk of mortality in all patients with GC compared with patients with low expression of those genes. Furthermore, protective effects may additionally be observed in patients with intestinal-type GC with high expression of ADH1B (log-rank P=0.031; HR=0.64; 95% CI: 0.43–0.96) and patients with diffuse-type GC with high expression of ADH1A (log-rank P=0.014; HR=0.51; 95% CI: 0.3–0.88), ADH1B (log-rank P=0.04; HR=0.53; 95% CI: 0.29–0.98), ADH 4 (class II), π polypeptide (log-rank P=0.033; HR=0.58; 95% CI: 0.35–0.96) and ADH 6 (class V) (log-rank P=0.037; HR=0.59; 95% CI: 0.35–0.97) resulting in a significantly decreased risk of mortality compared with patients with low expression of those genes. In contrast, patients with diffuse-type GC with high expression of ADH5 (log-rank P=0.044; HR=1.66; 95% CI: 1.01–2.74) were significantly correlated with a poor prognosis. The results of the present study suggest that ADH1A and ADH1B may be potential prognostic biomarkers of GC, whereas the prognostic value of other ADH genes requires further investigation.

A meta-analysis of alcohol consumption and thyroid cancer risk

Background

It is still inconclusive whether alcohol consumption affects the risk of thyroid cancer. We conducted a meta-analysis of available epidemiological data to address this issue.

Results

Compared with nondrinkers, the pooled relative risks (RRs) and corresponding 95% confidential intervals (CIs) of thyroid cancer were 0.80 (95% CI 0.71-0.90) for any drinkers, 0.81 (95% CI 0.70-0.93) for light and 0.71 (95% CI 0.63-0.79) for moderate drinkers. The dose–response analysis suggested that there is no evidence of a dose-risk relationship between alcohol intaking and thyroid cancer risk (P = 0.112).

Methods

Eligible studies were identified by searching PubMed and EMbase databases. A total of 24 studies, included 9,990 cases with thyroid cancer, were included in this meta-analysis. We defined light alcohol intake as ≤ one drink/day and moderate as >one drink/day. The summary risk estimates were calculated by the random effects model. A dose-response analysis was also conducted for modeling the dose-risk relation.

Conclusion

This meta-analysis confirmed an inverse association between alcohol consumption and thyroid cancer risk. Further studies are needed to better understand the potential mechanisms underlying this association.

Effects of interactions between common genetic variants and alcohol consumption on colorectal cancer risk

BACKGROUND

Genome-wide association studies (GWAS) have identified approximately 40 common genetic loci associated with colorectal cancer risk. To investigate possible gene-environment interactions (GEIs) between GWAS-identified single-nucleotide polymorphisms (SNPs) and alcohol consumption with respect to colorectal cancer, a hospital-based case-control study was conducted.

RESULTS

Higher levels of alcohol consumption as calculated based on a standardized definition of a drink (1 drink=12.5g of ethanol) were associated with increased risk of colorectal cancer (OR=2.47, 95% CI=1.62-3.76 for heavy drinkers [>50g/day] compared to never drinkers; ptrend<0.01). SNP rs6687758 near the DUSP10 gene at 1q41 had a statistically significant interaction with alcohol consumption in analyses of standardized drinks (p=4.6×10-3), although this did not surpass the corrected threshold for multiple testing. When stratified by alcohol consumption levels, in an additive model the risk of colorectal cancer associated with the G allele of rs6687758 tended to increase among individuals in the heavier alcohol consumption strata. A statistically significant association between rs6687758 and colorectal cancer risk was observed among moderate alcohol drinkers who consumed between >12.5 and ≤50g of alcohol per day (OR=1.46, 95% CI=1.01-2.11).

METHODS

A total of 2,109 subjects (703 colorectal cancer patients and 1,406 healthy controls) were recruited from the Korean National Cancer Center. For genotyping, 30 GWAS-identified SNPs were selected. A logistic regression model was used to evaluate associations of SNPs and alcohol consumption with colorectal cancer risk. We also tested GEIs between SNPs and alcohol consumption using a logistic model with multiplicative interaction terms.

CONCLUSIONS

Our results suggest that SNP rs6687758 at 1q41 may interact with alcohol consumption in the etiology of colorectal cancer.

Constitutional and functional genetics of human alcohol-related hepatocellular carcinoma

Exploration of the constitutional genetics of hepatocellular carcinoma (HCC) has identified numerous variants associated with a higher risk of liver cancer in alcoholic cirrhotic patients. Although Genome-Wide Association studies have not been carried out in the field of alcohol-related HCC, common single nucleotide polymorphisms conferring a small increase in the risk of liver cancer risk have been identified and shown to modulate ethanol metabolism, inflammation, oxidative stress, iron or lipid metabolism. Specific patterns of gene mutations including CTNNB1, TERT, ARID1A and SMARCA2 exist in alcohol-related HCC. Moreover, a specific mutational process observed at the nucleotide level by next generation sequencing has revealed cooperation between alcohol and tobacco in the development of HCC. Combining this genetic information with epidemiological and clinical data that might define specific HCC risk classes and refine surveillance strategies needs to be assessed in large prospective cohorts of patients with alcoholic cirrhosis.

AFB1 hepatocarcinogenesis is via lipid peroxidation that inhibits DNA repair, sensitizes mutation susceptibility and induces aldehyde-DNA adducts at p53 mutational hotspot codon 249

Aflatoxin B1 (AFB1) contamination in the food chain is a major cause of hepatocellular carcinoma (HCC). More than 60% of AFB1 related HCC carry p53 codon 249 mutations but the causal mechanism remains unclear. We found that 1) AFB1 induces two types of DNA adducts in human hepatocytes, AFB1-8,9-epoxide-deoxyguanosine (AFB1-E-dG) induced by AFB1-E and cyclic α-methyl-γ-hydroxy-1,N2-propano-dG (meth-OH-PdG) induced by lipid peroxidation generated acetaldehyde (Acet) and crotonaldehyde (Cro); 2) the level of meth-OH-PdG is >30 fold higher than the level of AFB1-E-dG; 3) AFB1, Acet, and Cro, but not AFB1-E, preferentially induce DNA damage at codon 249; 4) methylation at -CpG- sites enhances meth-OH-PdG formation at codon 249; and 5) repair of meth-OH-PdG at codon 249 is poor. AFB1, Acet, and Cro can also inhibit DNA repair and enhance hepatocyte mutational sensitivity. We propose that AFB1-induced lipid peroxidation generated aldehydes contribute greatly to hepatocarcinogenesis and that sequence specificity of meth-OH-PdG formation and repair shape the codon 249 mutational hotspot.

Do alcoholic beverages, obesity and other nutritional factors modify the risk of familial colorectal cancer? A systematic review

PURPOSE

Individuals with family history of colorectal cancer are at higher risk of colorectal cancer than the general population. Until now, guidelines for familial colorectal cancer risk have only pointed at early diagnosis efforts via screening tests and surveillance, and payed scarce or no attention to lowering exposure to modifiable risk factors, notably nutritional factors.

METHODS

We conducted a systematic review of epidemiological studies investigating the associations between nutritional factors, family history of colorectal cancer, and colorectal cancer risk. From the 5312 abstracts identified until December 2016, 184 full text articles were examined for eligibility. Finally, 31 articles (21 from case-control studies, 9 from cohort studies and 1 from an intervention study) met inclusion criteria and were analyzed.

RESULTS

Mainly, the combinations of family history of colorectal cancer and higher consumptions of alcoholic beverages, red or processed meat, or overweight/obesity increase the risk of colorectal cancer. Consistently, a strong increase is observed with the combinations of family history of colorectal cancer and unhealthy dietary patterns/lifestyles. Statistically significant interactions between these nutritional factors, family history of colorectal cancer and colorectal cancer risk are reported. Other data are inconclusive and additional prospective studies are needed.

CONCLUSIONS

For the first time, our findings highlight that addressing high consumption of alcoholic beverages, red or processed meat, and overweight/obesity, and more largely the exposure to multiple unhealthy dietary/nutritional behaviors could offer new perspectives of prevention to individuals with family history of colorectal cancer. A better information of these patients and of health professionals on these nutritional modifiable risk factors is recommended.

Investigating the Association between Alcohol and Risk of Head and Neck Cancer in Taiwan

Although alcohol is an established risk factor of head and neck cancer (HNC), insufficiencies exist in the literature in several aspects. We analyzed detailed alcohol consumption data (amount and type of alcoholic beverage) of 811 HNC patients and 940 controls to evaluate the association between alcohol and HNC by HNC sites and by genotypes of ADH1B and ALDH2. Alcohol was associated with an increased HNC risk in a dose-response relationship, with the highest risk observed for hypopharyngeal cancer, followed by oropharyngeal and laryngeal cancers. Liquor showed a stronger positive association with HNC than beer and wine. The highest HNC risk occurred in individuals with the slow ADH1B and slow/non-functional ALDH2 genotype combination. In our study population, 21.8% of HNCs, 55.7% of oropharyngeal cancers, and 89.1% of hypopharyngeal cancers could be attributed to alcohol. Alcohol accounted for 47.3% of HNCs among individuals with the slow ADH1B and slow/non-functional ALDH2 genotype combination. The HNC risk associated with alcohol became comparable to that of never/occasional drinkers after ten or more years of cessation from regular alcohol drinking. In conclusion, alcohol use is associated with an increased HNC risk, particularly for individuals with slow ethanol metabolism. HNC incidence may be reduced by alcohol cessation.

Alcohol and Cancer: Mechanisms and Therapies

Several scientific and clinical studies have shown an association between chronic alcohol consumption and the occurrence of cancer in humans. The mechanism for alcohol-induced carcinogenesis has not been fully understood, although plausible events include genotoxic effects of acetaldehyde, cytochrome P450 2E1 (CYP2E1)-mediated generation of reactive oxygen species, aberrant metabolism of folate and retinoids, increased estrogen, and genetic polymorphisms. Here, we summarize the impact of alcohol drinking on the risk of cancer development and potential underlying molecular mechanisms. The interactions between alcohol abuse, anti-tumor immune response, tumor growth, and metastasis are complex. However, multiple studies have linked the immunosuppressive effects of alcohol with tumor progression and metastasis. The influence of alcohol on the host immune system and the development of possible effective immunotherapy for cancer in alcoholics are also discussed here. The conclusive biological effects of alcohol on tumor progression and malignancy have not been investigated extensively using an animal model that mimics the human disease. This review provides insights into cancer pathogenesis in alcoholics, alcohol and immune interactions in different cancers, and scope and future of targeted immunotherapeutic modalities in patients with alcohol abuse.

Correlation between Oxidative Stress, Nutrition, and Cancer Initiation

Inadequate or excessive nutrient consumption leads to oxidative stress, which may disrupt oxidative homeostasis, activate a cascade of molecular pathways, and alter the metabolic status of various tissues. Several foods and consumption patterns have been associated with various cancers and approximately 30-35% of the cancer cases are correlated with overnutrition or malnutrition. However, several contradictory studies are available regarding the association between diet and cancer risk, which remains to be elucidated. Concurrently, oxidative stress is a crucial factor for cancer progression and therapy. Nutritional oxidative stress may be induced by an imbalance between antioxidant defense and pro-oxidant load due to inadequate or excess nutrient supply. Oxidative stress is a physiological state where high levels of reactive oxygen species (ROS) and free radicals are generated. Several signaling pathways associated with carcinogenesis can additionally control ROS generation and regulate ROS downstream mechanisms, which could have potential implications in anticancer research. Cancer initiation may be modulated by the nutrition-mediated elevation in ROS levels, which can stimulate cancer initiation by triggering DNA mutations, damage, and pro-oncogenic signaling. Therefore, in this review, we have provided an overview of the relationship between nutrition, oxidative stress, and cancer initiation, and evaluated the impact of nutrient-mediated regulation of antioxidant capability against cancer therapy.

Evaluation of the correlation of vasculogenic mimicry, ALDH1, KAI1 and microvessel density in the prediction of metastasis and prognosis in colorectal carcinoma

Background

Metastasis and recurrence are the most common reasons for treatment failure of colorectal carcinoma (CRC). Vasculogenic mimicry (VM, blood supply formation often seen in highly aggressive tumors), Aldehyde dehydrogenase 1 (ALDH1, a biomarker of cancer stem cells), KAI1 (a suppressor gene of tumor metastasis) are all valuable factors for metastasis and prognosis in diverse human cancers. However, the correlation of VM, ALDH1, KAI1 and microvessel density (MVD) in CRC is unclear. In this study, we analyzed the correlations among VM, ALDH1, KAI1 and MVD, as well as their respective correlations with clinicopathological parameters and survival in CRC.

Methods

The level of VM, ALDH1, KAI1 and MVD in 204 whole tissue samples of CRC were examined by immunhistochemistry. Clinical data was also collected.

Results

Levels of VM, ALDH1 and MVD were significantly higher, and levels of KAI1 significantly lower, in CRC tissues than in normal colorectal tissues. Levels of VM, ALDH1 and MVD were positively associated with invasion of depth, lymph node metastasis (LNM), distant metastasis and tumor-node-metastasis (TNM) stages, and negatively with patients’ overall survival (OS). Levels of KAI1 was negatively correlated with invasion of depth, LNM, distant metastasis and TNM stages, and the KAI1 positive expression subgroup had significantly longer OS than did the KAI1- subgroup. In multivariate analysis, high levels of VM, ALDH1 and KAI1, as well as TNM stages were independently correlated with lower OS in patients with CRC.

Conclusions

VM, MVD and the expression of ALDH1 and KAI1 may represent promising metastatic and prognostic biomarkers, as well as potential therapeutic targets for CRC.

Effect of alcohol and its metabolites in lung cancer: CAPUA study

BACKGROUND AND OBJECTIVE

Alcohol and its metabolites play an important role in carcinogenesis. This effect could be modulated by polymorphisms in genes encoding enzymes involved in the metabolism of alcohol and folate. Therefore, we analyzed the effect of alcohol consumption and ADH1B Arg48His, ADH1B Arg370Cys, ADH1C Ile349Val, ALDH2 Glu540Lys, CYP2E1 RsaI, CYP2E1 DraI, CYP2E1 TaqI and MTHFR C677T polymorphisms on the risk of developing lung cancer.

PATIENTS AND METHODS

We included 876 lung cancer cases and 840 controls of the CAPUA hospital-based case-control study. Genotyping was performed using the Sequenom MassArray (iPLEX GOLD) technology.

RESULTS

An alcohol consumption of 0.1-9.9g/day decreased lung cancer risk (OR_adjusted=0.71; 95% CI 0.48-1.05), although statistical significance was not achieved. A consumption≥30g/day of alcohol and≥36PY of tobacco increases lung cancer risk (OR_adjusted=26.68; 95% CI 12.69-56.10). On the other hand, a high consumption of vegetables (≥116.65g/day) and fruits (≥233.13g/day) decreases lung cancer risk with an alcohol consumption of 0.1-9.9g/day (OR_adjusted=0.52; 95% CI 0.30-0.89; OR_adjusted=0.58; 95% CI 0.33-1.03, respectively). An alcohol consumption of 10-29.9g/day in ADH1B 48His allele-carriers increases lung cancer risk (OR_adjusted=3.32; 95% CI 1.03-10.70).

CONCLUSIONS

Alcohol and polymorphisms in genes involved in the metabolism of alcohol and folate are related to the onset of lung cancer.

Effects of alcohol abstinence on glucose metabolism in Japanese men with elevated fasting glucose: A pilot study

It has been demonstrated that moderate alcohol consumption provides protection against the development of type 2 diabetes. However, several other reports suggested that moderate alcohol intake may increase the risk of type 2 diabetes in non-obese Japanese. The aim of present study was to investigate the effect of 1-week alcohol abstinence on hepatic insulin sensitivity and fasting plasma glucose (FPG) in non-obese Japanese men. We recruited 8 non-obese Japanese men with mildly elevated FPG and drinking habits alcohol (mean frequency; 5.6 ± 2.5 times/week, mean alcohol consumption; 32.1 ± 20.0 g/day). Before and after the 1-week alcohol abstinence, we used the 2-step hyperinsulinemic-euglycemic clamp to measure endogenous glucose production (EGP) and insulin sensitivity (IS) in muscle and liver. One-week alcohol abstinence significantly reduced both FPG by 7% (from 105.5 ± 11.7 to 98.2 ± 7.8 mg/dl, P < 0.01) and fasting EGP by 6% (from 84.1 ± 4.2 to 77.6 ± 1.6 mg/m² per min, P < 0.01), respectively. Two–step clamp study showed that alcohol abstinence significantly improved hepatic-IS, but not muscle-IS. In conclusion, one week alcohol abstinence improved hepatic IS and FPG in non-obese Japanese men with mildly elevated FPG and drinking habits alcohol.

Alcohol consumption and prostate cancer incidence and progression: A Mendelian randomisation study

Prostate cancer is the most common cancer in men in developed countries, and is a target for risk reduction strategies. The effects of alcohol consumption on prostate cancer incidence and survival remain unclear, potentially due to methodological limitations of observational studies. In this study, we investigated the associations of genetic variants in alcohol-metabolising genes with prostate cancer incidence and survival. We analysed data from 23,868 men with prostate cancer and 23,051 controls from 25 studies within the international PRACTICAL Consortium. Study-specific associations of 68 single nucleotide polymorphisms (SNPs) in 8 alcohol-metabolising genes (Alcohol Dehydrogenases (ADHs) and Aldehyde Dehydrogenases (ALDHs)) with prostate cancer diagnosis and prostate cancer-specific mortality, by grade, were assessed using logistic and Cox regression models, respectively. The data across the 25 studies were meta-analysed using fixed-effect and random-effects models. We found little evidence that variants in alcohol metabolising genes were associated with prostate cancer diagnosis. Four variants in two genes exceeded the multiple testing threshold for associations with prostate cancer mortality in fixed-effect meta-analyses. SNPs within ALDH1A2 associated with prostate cancer mortality were rs1441817 (fixed effects hazard ratio, HRfixed  = 0.78; 95% confidence interval (95%CI):0.66,0.91; p values = 0.002); rs12910509, HRfixed  = 0.76; 95%CI:0.64,0.91; p values = 0.003); and rs8041922 (HRfixed  = 0.76; 95%CI:0.64,0.91; p values = 0.002). These SNPs were in linkage disequilibrium with each other. In ALDH1B1, rs10973794 (HRfixed  = 1.43; 95%CI:1.14,1.79; p values = 0.002) was associated with prostate cancer mortality in men with low-grade prostate cancer. These results suggest that alcohol consumption is unlikely to affect prostate cancer incidence, but it may influence disease progression.

Activation of Human Salivary Aldehyde Dehydrogenase by Sulforaphane: Mechanism and Significance

Cruciferous vegetables contain the bio-active compound sulforaphane (SF) which has been reported to protect individuals against various diseases by a number of mechanisms, including activation of the phase II detoxification enzymes. In this study, we show that the extracts of five cruciferous vegetables that we commonly consume and SF activate human salivary aldehyde dehydrogenase (hsALDH), which is a very important detoxifying enzyme in the mouth. Maximum activation was observed at 1 μg/ml of cabbage extract with 2.6 fold increase in the activity. There was a ~1.9 fold increase in the activity of hsALDH at SF concentration of ≥ 100 nM. The concentration of SF at half the maximum response (EC₅₀ value) was determined to be 52 ± 2 nM. There was an increase in the V_max and a decrease in the K_m of the enzyme in the presence of SF. Hence, SF interacts with the enzyme and increases its affinity for the substrate. UV absorbance, fluorescence and CD studies revealed that SF binds to hsALDH and does not disrupt its native structure. SF binds with the enzyme with a binding constant of 1.23 x 10⁷ M^-1. There is one binding site on hsALDH for SF, and the thermodynamic parameters indicate the formation of a spontaneous strong complex between the two. Molecular docking analysis depicted that SF fits into the active site of ALDH3A1, and facilitates the catalytic mechanism of the enzyme. SF being an antioxidant, is very likely to protect the catalytic Cys 243 residue from oxidation, which leads to the increase in the catalytic efficiency and hence the activation of the enzyme. Further, hsALDH which is virtually inactive towards acetaldehyde exhibited significant activity towards it in the presence of SF. It is therefore very likely that consumption of large quantities of cruciferous vegetables or SF supplements, through their activating effect on hsALDH can protect individuals who are alcohol intolerant against acetaldehyde toxicity and also lower the risk of oral cancer development.

Susceptibility to oral squamous cell carcinoma: correlation with variants of CYP1A1-MspI, GSTT1, GSTM1, ALDH2, EC-SOD and Lifestyle factors

In order to investigate the association between polymorphisms in genes encoding metabolizing enzymes (CYP1A1-MspI, EC-SOD (extracellular superoxide dismutase), GSTT1, GSTM1, ALDH2), cigarette and alcohol consumption, and the risk of oral squamous cell carcinoma, we conducted a prospective case-control study comprised of 750 individuals with oral squamous cell carcinoma (OSCC) and 750 healthy individuals. Data about smoking and drinking habits were collected along with other demographic and clinical information. Peripheral blood samples were collected for DNA extraction, and polymerase chain reaction (PCR) and PCR-RFLP (restriction fragment length polymorphism) were used to determine genotypes of CYP1A1, EC-SOD, GSTT1, GSTM1, ALDH2. The results showed that smoking and alcohol consumption were significantly more common among patients than controls (p <0.05). There were significant differences in the genotype distribution for each locus between groups, with the CYP1A1 (m2/ m2), EC-SOD (C/G), GSTT1 [-], GSTM1 [-] and ALDH2 (non G/G) genotypes being more common among patients (p <0.05). Furthermore, the majority of patients had at least two or more variant genotypes, while controls had one or no variant genotype (p <0.05). Finally, multiple variant genotypes combined with smoking, drinking, or both smoking and drinking significantly increased the risk of OSCC, with greater increase for heavier smoking/drinking. In brief, genetic polymorphism of CYP1A1, EC-SOD, GSTT1, GSTM1, and ALDH2 and smoking and drinking history are closely associated with susceptibility to OSCC.

Metastasis-associated in colon cancer-1 and aldehyde dehydrogenase 1 are metastatic and prognostic biomarker for non-small cell lung cancer

Background

Tumor recurrence and metastasis are the most common reason for treatment failure. Metastasis-associate in colon cancer-1 (MACC1) has been identified as a metastatic and prognostic biomarker for colorectal cancer and other solid tumors. Aldehyde dehydrogenase 1 (ALDH1), a marker of cancer stem cells, is also associated with metastasis and poor prognosis in many tumors. However, the prognostic value of either MACC1 or ALDH1 in non-small cell lung cancer (NSCLC) is unclear. In this study, we explored the relationship between MACC1 and ALDH1 expression, as well as their respective associations with clinicopathological features, to determine if either could be useful for improvement of survival prognosis in NSCLC.

Methods

The expression levels of both MACC1 and ALDH1 in 240 whole tissue sections of NSCLC were examined by immunohistochemistry. Clinical data were also collected.

Results

MACC1 and ALDH1 were significantly overexpressed in NSCLC tissues when compared to levels in normal lung tissues. Investigation of associations between MACC1 or ALDH1 protein levels with clinicopathological parameters of NSCLC revealed correlations between the expression of each with tumor grade, lymph node metastasis, and tumor node metastasis. The overall survival of patients with MACC1- or ALDH1-positive NSCLC tumors was significantly lower than that of those who were negative. Importantly, multivariate analysis suggested that positive expression of either MACC1 or ALDH1, as well as TNM stage, could be independent prognostic factors for overall survival in patients with NSCLC.

Conclusions

MACC1 and ALDH1 may represent promising metastatic and prognostic biomarkers, as well as potential therapeutic targets, for NSCLC.

Asian flushing: genetic and sociocultural factors of alcoholism among East asians

Alcohol use can lead to a cascade of problems such as increased chances of risky behavior and negative health consequences, including alcoholic liver disease and upper gastric and liver cancer. Ethanol is metabolized mainly by 2 major enzymes: alcohol dehydrogenase (ADH) and acetaldehyde dehydrogenase (ALDH). Genetic variations of genes encoding the 2 enzymes are very common among East Asians but relatively rare for most other populations. Facial flushing and other physical discomforts after alcohol drinking triggered by accumulation of acetaldehyde through defective genes for ADH and ALDH have been reported. Approximately 40% of East Asians (Chinese, Japanese, and Korean) show facial flushing after drinking alcohol, known as "Asian flush," which is characterized by adverse reactions on alcohol drinking in individuals possessing the fasting metabolizing alleles for ADH, ADH1B*2, and ADH1C*1, and the null allele for ALDH and ALDH2*2. Alcoholism is determined not only by the genetic deficiency but also by behaviors that involve complex interactions between genetic and sociocultural factors. The purpose of this article was to provide nurses with the most current information about genetic and sociocultural influences on alcoholism and alcohol-related health problems specifically for East Asians and implications of this knowledge to nursing practice. The physiological phenomenon of genes and genetics in relation to alcohol metabolism in this special population is emphasized.

Phenome-Wide Association Study for Alcohol and Nicotine Risk Alleles in 26394 Women

To identify novel traits associated with alleles known to predispose to alcohol and nicotine use, we conducted a phenome-wide association study (PheWAS) in a large multi-population cohort. We investigated 7688 African-Americans, 1133 Asian-Americans, 14 081 European-Americans, and 3492 Hispanic-Americans from the Women's Health Initiative, analyzing alleles at the CHRNA3-CHRNA5 locus, ADH1B, and ALDH2 with respect to phenotypic traits related to anthropometric characteristics, dietary habits, social status, psychological traits, reproductive history, health conditions, and nicotine/alcohol use. In ADH1B trans-population meta-analysis and population-specific analysis, we replicated prior associations with drinking behaviors and identified multiple novel phenome-wide significant and suggestive findings related to psychological traits, socioeconomic status, vascular/metabolic conditions, and reproductive health. We then applied Bayesian network learning algorithms to provide insight into the causative relationships of the novel ADH1B associations: ADH1B appears to affect phenotypic traits via both alcohol-mediated and alcohol-independent effects. In an independent sample of 2379 subjects, we also replicated the novel ADH1B associations related to socioeconomic status (household gross income and highest grade finished in school). For CHRNA3-CHRNA5 risk alleles, we replicated association with smoking behaviors, lung cancer, and asthma. There were also novel suggestive CHRNA3-CHRNA5 findings with respect to high-cholesterol-medication use and distrustful attitude. In conclusion, the genetics of alcohol and tobacco use potentially has broader implications on physical and mental health than is currently recognized. In particular, ADH1B may be a gene relevant for the human phenome via both alcohol metabolism-related mechanisms and other alcohol metabolism-independent mechanisms.

Alcoholic Liver Disease: High Risk or Low Risk for Developing Hepatocellular Carcinoma?

In this review we critically assess the literature to evaluate the level of risk posed by alcohol as both a primary etiology of hepatocellular carcinoma (HCC) and as a cofactor in its development. Although there have been conflicting findings, based on the body of evidence to date, it appears that the linkage between compensated alcoholic liver disease-associated cirrhosis and HCC is best characterized as medium-high risk, with the risk increasing with age and with quantity and duration of alcohol consumption and is more pronounced in females. While abstinence is the most effective way to reduce HCC risk, its effect seems largely dependent on the severity of liver damage at the point of cessation. Alcohol clearly interacts with other etiologies and conditions including viral hepatitis B and C, hereditary hemochromatosis, diabetes, and obesity to increase the risk for developing HCC, either synergistically or additively. Continued progress in genetics, especially through mechanistic-based and genome-wide association studies may ultimately identify which single nucleotide polymorphisms are risk factors for the onset of alcoholic liver disease and its progression to HCC and lead to the development of targeted therapeutics which may help providers better manage at-risk patients.

Hairpin Ribozyme Genes Curtail Alcohol Drinking: from Rational Design to in vivo Effects in the Rat

Ribozyme genes were designed to reduce voluntary alcohol drinking in a rat model of alcohol dependence. Acetaldehyde generated from alcohol in the liver is metabolized by the mitochondrial aldehyde dehydrogenase (ALDH2) such that diminishing ALDH2 activity leads to the aversive effects of blood acetaldehyde upon alcohol intake. A stepwise approach was followed to design genes encoding ribozymes targeted to the rat ALDH2 mRNA. In vitro studies of accessibility to oligonucleotides identified suitable target sites in the mRNA, one of which fulfilled hammerhead and hairpin ribozyme requirements (CGGUC). Ribozyme genes delivered in plasmid constructs were tested in rat cells in culture. While the hairpin ribozyme reduced ALDH2 activity 56% by cleavage and blockade (P < 0.0001), the hammerhead ribozyme elicited minor effects by blockade. The hairpin ribozyme was tested in vivo by adenoviral gene delivery to UChB alcohol drinker rats. Ethanol intake was curtailed 47% for 34 days (P < 0.0001), while blood acetaldehyde more than doubled upon ethanol administration and ALDH2 activity dropped 25% in liver homogenates, not affecting other ALDH isoforms. Thus, hairpin ribozymes targeted to 16 nt in the ALDH2 mRNA provide durable and specific effects in vivo, representing an improvement on previous work and encouraging development of gene therapy for alcoholism.

Alcohol consumption and corresponding factors: A novel perspective on the risk factors of esophageal cancer

Esophageal cancer is the eighth most common type of cancer in the world, and the sixth most common cause of mortality from cancer. Alcohol consumption is the major risk factor for esophageal cancer, due to the worldwide prevalence and high carcinogenicity of the ethanol metabolite. In epidemiological studies, the efficiency of alcohol intake to enhance the risk of esophageal cancer is altered by daily ethanol consumption, type of alcoholic beverages ingested, time since quitting drinking, age of drinking initiation, differences in population and subtypes of esophageal cancer. Corresponding factors, including gene polymorphisms, tobacco smoking, oral microorganisms and folate deficiency, reveal a synergistic effect in concurrent alcohol users that may lead to an increased risk of developing esophageal cancer. Consequently, esophageal cancer prevention involves multiple aspects, including quitting drinking and smoking, maintaining an adequate oral health and ingesting adequate quantities of folate, particularly in genetically high-risk populations.

Alcohol dehydrogenase and aldehyde dehydrogenase in malignant neoplasms

According to International Agency for Research on Cancer, ethanol and acetaldehyde belong to group 1 of human carcinogens. The accurate mechanism by which alcohol consumption enhances carcinogenesis is still unexplained. Alcohol is oxidized primarily by alcohol dehydrogenase (ADH) to acetaldehyde, a substance capable of initiating carcinogenesis by forming adducts with proteins and DNA and causing mutations. Next, acetaldehyde is metabolized by aldehyde dehydrogenase (ALDH) to acetate. In tissues of many cancers, we can observe significantly higher activity of total alcohol dehydrogenase with any change in aldehyde dehydrogenase activity in comparison with healthy cells. Moreover, in malignant diseases of digestive system, significantly increased activity of ADH isoenzymes class I, III and IV was found. The gynecological, brain and renal cancers exhibit increased activity of class I ADH. ADH and ALDH can play also a crucial regulatory role in initiation and progression of malignant diseases by participation in retinoic acid synthesis and elimination of toxic acetaldehyde. Besides, changes of enzymes activities in tumor cells are reflected in serum of cancer patients, which create the possibilities of application ADH isoenzymes as cancer markers.

Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling

Background

The endoplasmic reticulum (ER) plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH).

Methods

ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs). Myocardial mechanical and intracellular Ca²⁺ properties, ER stress, autophagy and associated cell signaling molecules were evaluated.

Results

ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca²⁺ homeostasis), oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62), along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene.

Conclusions

Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy.

NEK2 mediates ALDH1A1-dependent drug resistance in multiple myeloma

We reported previously that increased expression of aldehyde dehydrogenase 1 (ALDH1) in multiple myeloma (MM) is a marker of tumor-initiating cells (TICs) that is further associated with chromosomal instability (CIN). Here we demonstrate that member A1 of the ALDH1 family of proteins, ALDH1A1, is most abundantly expressed in myeloma. Enforced expression of ALDH1A1 in myeloma cells led to increased clonogenicity, tumor formation in mice, and resistance to myeloma drugs in vitro and in vivo. The mechanism underlying these phenotypes included the ALDH1A1-dependent activation of drug-efflux pump, ABCB1, and survival proteins, AKT and BCL2. Over expression of ALDH1A1 in myeloma cells led to increased mRNA and protein levels of NIMA-related kinase 2 (NEK2), whereas shRNA-mediated knock down of NEK2 decreased drug efflux pump activity and drug resistance. The activation of NEK2 in myeloma cells relied on the ALDH1A1-dependent generation of the retinoid X receptor α (RXRα) ligand, 9-cis retinoic acid (9CRA) - not the retinoic acid receptor α (RARα) ligand, all-trans retinoic acid (ATRA). These findings implicate the ALDH1A1-RXRα-NEK2 pathway in drug resistance and disease relapse in myeloma and suggest that specific inhibitors of ALDH1A1 are worthy of consideration for clinical development of new approaches to overcome drug resistance in myeloma.

Interaction of Polymorphisms of Resistin Gene Promoter -420C/G, Glutathione Peroxidase -1 Gene Pro198Leu and Cigarette Smoking in Nonalcoholic Fatty Liver Disease

BACKGROUND

Many studies have suggested that cigarette smoking and polymorphisms of resistin and glutathione peroxidase-1 (GPx-1) genes are closely correlated with the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, few reports have investigated these associations with respect to NAFLD susceptibility. We, therefore, examined the distribution of polymorphisms in GPx-1 and resistin genes in NAFLD patients and healthy controls and analyzed the relationship between these polymorphisms and smoking status.

METHODS

Nine hundred NAFLD patients and 900 healthy controls were selected, and the genetic polymorphisms of resistin gene promoter-420C/G and GPx-1 gene Pro198Leu were analyzed by polymorphism-polymerase chain reaction (PCR) in DNA extracted from peripheral blood leukocytes. Interactions between the two mutants and the gene-environment interaction with cigarette smoking were also analyzed.

RESULTS

Genotype frequencies of -420C/G (GG) and Pro198Leu (LL) were significantly higher in NAFLD cases (49.56% and 50.11%, respectively) compared with healthy controls (23.67% and 24.22%, respectively) (P = 0.0069; P = 0.0072). Moreover, the risk of NAFLD with -420C/G (GG) was significantly higher than in controls (odds ratio [OR] =3.1685, 95% confidence interval (CI) =1.9366-5.2073). Individuals carrying Pro198Leu (LL) had a high risk of NAFLD (OR = 3.1424, 95% CI = 1.7951-5.2367). Combined analysis of the polymorphisms showed that the -420C/G (GG)/Pro198Leu (LL) genotype was significantly more common in the NAFLD group than in the control group (39.44% vs. 12.78%, respectively, P = 0.0054), while individuals with -420C/G (GG)/Pro198Leu (LL) had a high risk of NAFLD (OR = 5.0357, 95% CI = 3.1852-7.8106). Moreover, the cigarette smoking rate in the NAFLD group was significantly higher than in the control group (OR = 1.8990, P = 0.0083 in the smoking index (SI) ≤400 subgroup; OR = 5.0937, P = 0.0051 in the SI >400 subgroup), and statistical analysis suggested a positive interaction between cigarette smoking and -420C/G (GG) (γ = 5.6018 in the SI ≤400 subgroup; γ = 4.4770 in the SI >400 subgroup) and Pro198Leu (LL) (γ = 5.7715 in the SI ≤400 subgroup; γ = 4.5985 in the SI >400 subgroup) in increasing the risk of NAFLD.

CONCLUSION

NAFLD risk factors include -420C/G (GG), Pro198Leu (LL) and cigarette smoking, and these three factors have a significant additive effect on NAFLD risk.

Update on Head and Neck Cancer: Current Knowledge on Epidemiology, Risk Factors, Molecular Features and Novel Therapies

Tobacco use and alcohol consumption are the main risk factors associated with head and neck squamous cell carcinoma (SCC) development due to their cytotoxic and mutagenic effects on the exposed epithelia of the upper aerodigestive tract. Epstein-Barr virus (EBV) and high-risk human papillomaviruses (HPVs), both encoding viral oncoproteins able to interfere with cell cycle control, have been recognized as the etiological agents of nasopharynx carcinoma and a fraction of oropharyngeal carcinoma, respectively. Head and neck SCC is a deadly disease and despite innovative treatments represents a major challenge for patients. Recently, a number of genomic studies have highlighted the molecular heterogeneity of head and neck SCC based on methylation profiles, microRNA expression, mutated genes and new druggable pathways which may represent new targets for cancer-tailored therapies. To date, cetuximab is the only FDA-approved anti-epidermal growth factor receptor therapy for the treatment of head and neck SCC. In addition, a number of monoclonal antibodies targeting AKT, mTOR and PI3K pathways are under evaluation. Several therapeutic vaccines against HPV16 and EBV proteins are also under study. The purpose of this article is to review the epidemiology, pathogenesis and molecular features of head and neck SCC, with an emphasis on new therapies.

Alcohol intake, beverage choice, and cancer: a cohort study in a large kaiser permanente population

The authors studied incident cancer risk from 1978 to 1985 and through follow-up in 2012 relative to light-to-moderate and heavy drinking and to the choice of alcoholic beverage in a cohort of 124,193 persons. With lifelong abstainers as referent, heavy drinking (≥ 3 drinks per day) was associated with increased risk of 5 cancer types: upper airway/digestive tract, lung, female breast, colorectal, and melanoma, with light-to-moderate drinking related to all but lung cancer.

Aldehyde dedydrogenase-2 plays a beneficial role in ameliorating chronic alcohol-induced hepatic steatosis and inflammation through regulation of autophagy

BACKGROUND & AIMS

Mitochondrial aldehyde dehydrogenase (ALDH2) plays a critical role in the detoxification of the ethanol metabolite acetaldehyde. This study was designed to examine the impact of global ALDH2 overexpression on alcohol-induced hepatic steatosis.

METHODS

Wild type Friend virus B (FVB) and ALDH2 transgenic mice were placed on a 4% alcohol or control diet for 12 weeks. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin and cholesterol, hepatic triglyceride, steatosis, fat metabolism-related proteins, pro-inflammatory cytokines, glutathione (GSH), oxidized glutathione (GSSG), autophagy and autophagy signalling were examined. The role of autophagy was evaluated in alcohol dehydrogenase 1 (ADH1)-transfected human hepatocellular liver carcinoma cells (VA-13) treated with or without the autophagy inducer rapamycin and lysosomal inhibitors.

RESULTS

Chronic alcohol intake led to elevated AST-, ALT-levels, bilirubin, AST/ALT ratio, cholesterol, hepatic triglycerides and hepatic fat deposition as evidenced by H&E and Oil Red O staining. Hepatic fat deposition was associated with disturbed levels of fat metabolism-related proteins (fatty acid synthase, SCD1), upregulated interleukin-6, TNF-α, cyclooxygenase, oxidative stress, and loss of autophagy, effects which were attenuated or ablated by the ALDH2 transgene. Moreover, ethanol (100 mM) and acetaldehyde (100 and 500 μM) increased levels of IL-6 and IFN-γ, and suppressed autophagy in VA-13 cells, effects which were markedly alleviated by rapamycin. In addition, lysosomal inhibitors mimicked ethanol-induced p62 accumulation with little additive effect with ethanol. Ethanol significantly suppressed LC3 conversion in the presence of lysosomal inhibitors.

CONCLUSIONS

In summary, our results revealed that ALDH2 plays a beneficial role in ameliorating chronic alcohol intake-induced hepatic steatosis and inflammation through regulation of autophagy.

Genetic risk markers for hepatocellular carcinoma in patients with alcoholic liver disease

Various single nucleotide polymorphisms have been reported to be associated with a higher risk of hepatocellular carcinoma in alcoholic cirrhotic patients. Until now, only common variants conferring a small increase in liver cancer risk have been identified. These inherited factors are able to modulate several biological pathways involved in alcohol-induced hepatocarcinogenesis, such as ethanol metabolism, inflammation, oxidative stress, or iron and lipid homeostasis. How the combination of these variants might collectively define an individual genomic risk prediction is currently being investigated. The other challenge in clinical practice lies in defining how to integrate this genetic information with other clinical parameters so as to refine selection of alcoholic cirrhotic patients according to various classes of hepatocellular carcinoma risk.

A critical analysis of the relationship between aldehyde dehydrogenases-2 Glu487Lys polymorphism and colorectal cancer susceptibility

Studies investigating the association between genetic polymorphism of aldehyde dehydrogenases-2 (ALDH-2) Glu487Lys and colorectal cancer (CRC) risk have reported conflicting results. Given this uncertainty, we carried out a critical analysis of published case-control studies to derive a more precise estimation of this relationship. Published literature from PubMed, EMBASE and China Knowledge Resource Integrated Database were retrieved, and the literature search was updated in June 2014. Eleven studies comprising 6965 subjects were selected (2300 cases and 4665 controls). Overall, our study showed no statistical significance for CRC risk associated with any of the genetic models of ALDH-2 Glu487Lys polymorphism. When studies were stratified for control source, a decreased risk of CRC for participants with Lys/Lys was observed in population based case-control studies [Lys/Lys vs. (Glu/Lys + Glu/Glu): odds ratio (OR) = 0.57, 95% confidence interval (CI) = 0.38-0.87]. Furthermore, we also confirmed the significant correlation between Glu487Lys polymorphism and the influence on the risk of rectal cancer in males [Glu/Glu vs. (Glu/Lys + Lys/Lys): OR = 1.52, 95%CI = 1.10-2.08]. The combined effects of the two gene polymorphisms [ALDH-2 and alcohol dehydrogenase 1B (ADH-1B)] were also studied. Compared with subjects having ALDH-2 Lys+ with ADH-1B His/His, ORs and 95%CIs for those with ALDH-2 Glu/Glu and ADH-1B His/His was 3.42(0.57-20.38). Similar trends were observed for the other two types of comparisons. Our study supports that ALDH-2 Glu487Lys polymorphism is associated with significant reduced risks of CRC in population-based samples, and of rectal cancer in males.

Transgenic mouse models for alcohol metabolism, toxicity, and cancer

Alcohol abuse leads to tissue damage including a variety of cancers; however, the molecular mechanisms by which this damage occurs remain to be fully understood. The primary enzymes involved in ethanol metabolism include alcohol dehydrogenase (ADH), cytochrome P450 isoform 2E1, (CYP2E1), catalase (CAT), and aldehyde dehydrogenases (ALDH). Genetic polymorphisms in human genes encoding these enzymes are associated with increased risks of alcohol-related tissue damage, as well as differences in alcohol consumption and dependence. Oxidative stress resulting from ethanol oxidation is one established pathogenic event in alcohol-induced toxicity. Ethanol metabolism generates free radicals, such as reactive oxygen species (ROS) and reactive nitrogen species (RNS), and has been associated with diminished glutathione (GSH) levels as well as changes in other antioxidant mechanisms. In addition, the formation of protein and DNA adducts associated with the accumulation of ethanol-derived aldehydes can adversely affect critical biological functions and thereby promote cellular and tissue pathology. Animal models have proven to be valuable tools for investigating mechanisms underlying pathogenesis caused by alcohol. In this review, we provide a brief discussion on several animal models with genetic defects in alcohol-metabolizing enzymes and GSH-synthesizing enzymes and their relevance to alcohol research.

Correlations between polymorphisms of extracellular superoxide dismutase, aldehyde dehydrogenase-2 genes, as well as drinking behavior and pancreatic cancer

OBJECTIVE

To investigate the correlation between drinking behavior combined with polymorphisms of extracellular superoxide dismutase (EC-SOD) and aldehyde dehydrogenase-2 (ALDH2) genes and pancreatic cancer.

METHODS

The genetic polymorphisms of EC-SOD and ALDH2 were analyzed by polymerase chain reaction restriction fragment length polymorphism in the peripheral blood leukocytes obtained from 680 pancreatic cancer cases and 680 non-cancer controls. Subsequently the frequency of genotype was compared between the pancreatic cancer patients and the healthy controls.The relationship of drinking with pancreatic cancer was analyzed.

RESULTS

The frequencies of EC-SOD (C/G) and ALDH2 variant genotypes were 37.35% and 68.82% respectively in the pancreatic cancer cases, and were significantly higher than those in the healthy controls (21.03% and 44.56%, all P<0.01). People who carried EC-SOD (C/G) (OR=2.24, 95% CI= 1.81-4.03, P<0.01) or ALDH2 variant genotypes (OR=2.75, 95% CI=1.92-4.47, P<0.01) had a high risk to develop pancreatic cancer. Those who carried EC-SOD (C/G) genotype combined with ALDH2 variant genotype had a high risk for pancreatic cancer (29.56% vs. 6.76%, OR=7.69, 95% CI=3.58-10.51, P<0.01). The drinking rate of the pancreatic cancer group (64.12%) was significantly higher than that of the control group (40.15%; OR=2.66, 95% CI=1.30-4.42, P<0.01). An interaction between drinking and EC-SOD (C/G)/ALDH2 variant genotypes increased the risk of occurrence of pancreatic cancer (OR=25.00, 95% CI= 11.87-35.64, P<0.01).

CONCLUSION

EC-SOD (C/G), ALDH2 variant genotypes and drinking might be the risk factors of pancreatic cancer.

Alcohol consumption and persistent infection of high-risk human papillomavirus

Alcohol consumption is a possible co-factor of high-risk human papillomavirus (HR-HPV) persistence, a major step in cervical carcinogenesis, but the association between alcohol and continuous HPV infection remains unclear. This prospective study identified the association between alcohol consumption and HR-HPV persistence. Overall, 9230 women who underwent screening during 2002-2011 at the National Cancer Center, Korea were analysed in multivariate logistic regression. Current drinkers [odds ratio (OR) 2·49, 95% confidence interval (CI) 1·32-4·71] and drinkers for ⩾5 years (OR 2·33, 95% CI 1·17-4·63) had a higher risk of 2-year HR-HPV persistence (HPV positivity for 3 consecutive years) than non-drinkers and drinkers for <5 years, respectively (vs. HPV negativity for 3 consecutive years). A high drinking frequency (⩾twice/week) and a high beer intake (⩾3 glasses/occasion) had higher risks of 1-year (OR 1·80, 95% CI 1·01-3·36) HPV positivity for 2 consecutive years) and 2-year HR-HPV persistence (OR 3·62, 95% CI 1·35-9·75) than non-drinkers. Of the HPV-positive subjects enrolled, drinking habit (OR 2·68, 95% CI 1·10-6·51) and high consumption of beer or soju (⩾2 glasses/occasion; OR 2·90, 95% CI 1·06-7·98) increased the risk of 2-year consecutive or alternate HR-HPV positivity (vs. consecutive HPV negativity). These findings suggest that alcohol consumption might increase the risk of cervical HR-HPV persistence in Korean women.

Harmful and beneficial relationships between alcohol consumption and subclinical atherosclerosis

BACKGROUND AND AIMS

Arterial stiffness and increased intima-media wall thickness are two of the main predictors of cardiovascular disease (CVD). We evaluated whether brachial-ankle pulse wave velocity (baPWV) and common carotid artery intima-media wall thickness (CCA-IMT) are correlated with alcohol consumption in a cross-sectional study among Korean men and women aged 40 years and over.

METHODS AND RESULTS

All 5539 subjects (2121 men and 3418 women) were participants in the Multi-Rural Communities cohort (MRcohort) study, a part of the Korean Genome Epidemiology Study (KoGES). The baPWV was positively correlated with alcohol consumption in men (p for trend <0.0001). Age (middle-aged versus elderly) modified the effect of alcohol consumption on PWV. On the other hand CCA-IMT decreased with alcohol consumption in men. There was no favorable zone of alcohol consumption in terms of baPWV and CCA-IMT. Adjustment for lipid profiles substantially attenuated the relationship between alcohol consumption and CCA-IMT. There was no clear relation between alcohol consumption and baPWV/CCA-IMT in women.

CONCLUSIONS

Along with a linear harmful relationship between alcohol consumption and arterial stiffness in men there may also be a beneficial relationship between alcohol consumption and carotid intima-wall thickness. The effect of alcohol on arterial stiffness may be slightly stronger in elderly men, and the effect of alcohol on CCA-IMT may be mediated by lipid factors.

Alcohol drinking and risk of leukemia-a systematic review and meta-analysis of the dose-risk relation

The association between alcohol and leukemia risk has been addressed in several studies in the past two decades, but results have been inconsistent. Therefore, we conducted a systematic review and meta-analysis to quantify the dose-risk relation. Through the literature search up to August 2013, we identified 18 studies, 10 case-control and 8 cohorts, carried out in a total of 7142 leukemia cases. We derived pooled meta-analytic estimates using random-effects models, taking into account the correlation between estimates, and we performed a dose-risk analysis using a class of nonlinear random-effects meta-regression models. Stratified analyses were carried out on leukemia subtypes and groups, in order to identify possible etiologic differences. Compared with nondrinkers, the relative risks (RRs) for all leukemia were 0.94 [95% confidence interval (CI), 0.85-1.03], 0.90 (95% CI, 0.80-1.01) and 0.91 (95% CI, 0.81-1.02) for any, light (≤ 1 drink/day) and moderate to heavy (>1 drink/day) alcohol drinking, respectively. The summary RRs for any alcohol drinking were 1.47 (95% CI, 0.47-4.62) for acute lymphoblastic leukemia, 0.94 (95% CI 0.77-1.15) for chronic lymphocytic leukemia, 1.02 (95% CI, 0.86-1.21) for acute myeloid leukemia and 0.93 (95% CI 0.75-1.14) for chronic myeloid leukemia. The subgroup analysis on geographical area for all leukemia combined showed RRs of 0.84 (95% CI, 0.76-0.93), 0.92 (95% CI, 0.83-1.01) and 1.32 (95% CI, 1.02-1.70) for studies conducted in America, Europe and Asia, respectively. We did not find an increased risk of leukemia among alcohol drinkers. If any, a modest favorable effect emerged for light alcohol drinking, with a model-based risk reduction of approximately 10% in regular drinkers.

The interplay between alcohol consumption, oral hygiene, ALDH2 and ADH1B in the risk of head and neck cancer

Alcohol consumption is an established risk factor for head and neck cancer (HNC). The major carcinogen from alcohol is acetaldehyde, which may be produced by humans or by oral microorganisms through the metabolism of ethanol. To account for the different sources of acetaldehyde production, the current study examined the interplay between alcohol consumption, oral hygiene (as a proxy measure for the growth of oral microorganisms), and alcohol-metabolizing genes (ADH1B and ALDH2) in the risk of HNC. We found that both the fast (*2/*2) and the slow (*1/*1+ *1/*2) ADH1B genotypes increased the risk of HNC due to alcohol consumption, and this association differed according to the slow/non-functional ALDH2 genotypes (*1/*2+ *2/*2) or poor oral hygiene. In persons with the fast ADH1B genotype, the HNC risk associated with alcohol drinking was increased for those with the slow/non-functional ALDH2 genotypes. For those with the slow ADH1B genotypes, oral hygiene appeared to play an important role; the highest magnitude of an increased HNC risk in alcohol drinkers occurred among those with the worst oral hygiene. This is the first study to show that the association between alcohol drinking and HNC risk may be modified by the interplay between genetic polymorphisms of ADH1B and ALDH2 and oral hygiene. Although it is important to promote abstinence from or reduction of alcohol drinking to decrease the occurrence of HNC, improving oral hygiene practices may provide additional benefit.

ALDH2 mediates 5-nitrofuran activity in multiple species

Understanding how drugs work in vivo is critical for drug design and for maximizing the potential of currently available drugs. 5-nitrofurans are a class of prodrugs widely used to treat bacterial and trypanosome infections, but despite relative specificity, 5-nitrofurans often cause serious toxic side effects in people. Here, we use yeast and zebrafish, as well as human in vitro systems, to assess the biological activity of 5-nitrofurans, and we identify a conserved interaction between aldehyde dehydrogenase (ALDH) 2 and 5-nitrofurans across these species. In addition, we show that the activity of nifurtimox, a 5-nitrofuran anti-trypanosome prodrug, is dependent on zebrafish Aldh2 and is a substrate for human ALDH2. This study reveals a conserved and biologically relevant ALDH2-5-nitrofuran interaction that may have important implications for managing the toxicity of 5-nitrofuran treatment.

Genetic variants in nicotine addiction and alcohol metabolism genes, oral cancer risk and the propensity to smoke and drink alcohol: a replication study in India

BACKGROUND

Genetic variants in nicotinic acetylcholine receptor and alcohol metabolism genes have been associated with propensity to smoke tobacco and drink alcohol, respectively, and also implicated in genetic susceptibility to head and neck cancer. In addition to smoking and alcohol, tobacco chewing is an important oral cancer risk factor in India. It is not known if these genetic variants influence propensity or oral cancer susceptibility in the context of this distinct etiology.

METHODS

We examined 639 oral and pharyngeal cancer cases and 791 controls from two case-control studies conducted in India. We investigated six variants known to influence nicotine addiction or alcohol metabolism, including rs16969968 (CHRNA5), rs578776 (CHRNA3), rs1229984 (ADH1B), rs698 (ADH1C), rs1573496 (ADH7), and rs4767364 (ALDH2).

RESULTS

The CHRN variants were associated with the number of chewing events per day, including in those who chewed tobacco but never smoked (P =  0.003, P =  0.01 for rs16969968 and rs578776 respectively). Presence of the variant allele contributed to approximately 13% difference in chewing frequency compared to non-carriers. While no association was observed between rs16969968 and oral cancer risk (OR =  1.01, 95% CI =  0.83- 1.22), rs578776 was modestly associated with a 16% decreased risk of oral cancer (OR =  0.84, 95% CI =  0.72- 0.98). There was little evidence for association between polymorphisms in genes encoding alcohol metabolism and oral cancer in this population.

CONCLUSION

The association between rs16969968 and number of chewing events implies that the effect on smoking propensity conferred by this gene variant extends to the use of smokeless tobacco.

Alcoholic beverages and carbonated soft drinks: consumption and gastrointestinal cancer risks

Alcoholic beverages (ABs) and carbonated soft drinks (CSDs) are widely consumed worldwide. Given the high consumption of these beverages, the scientific community has increased its focus on their health impact. There is epidemiological evidence of a causal association between AB intake and digestive cancer, but the role of alcohol in determining cancer is not fully defined. Experimental studies have so far identified multiple mechanisms involved in carcinogenesis; ethanol itself is not carcinogenic but available data suggest that acetaldehyde (AA) and reactive oxygen species-both products of ethanol metabolism-have a genotoxic effect promoting carcinogenesis. Other carcinogenetic mechanisms include nutritional deficits, changes in DNA methylation, and impaired immune surveillance. As CSDs are often suspected to cause certain gastrointestinal disorders, consequently, some researchers have hypothesized their involvement in gastrointestinal cancers. Of all the ingredients, carbon dioxide is prevalently involved in the alteration of gastrointestinal physiology by a direct mucosal effect and indirect effects mediated by the mechanical pressure determined by gas. The role of sugar or artificial sweeteners is also debated as factors involved in the carcinogenic processes. However, several surveys have failed to show any associations between CSDs and esophageal, gastric, or colon cancers. On the other hand, a slight correlation between risk of pancreatic cancer and CSD consumption has been found.

Simultaneous determination of volatile organic compounds and carbonyls in mainstream cigarette smoke using a sorbent cartridge followed by two-step elution

We developed a simple method for the simultaneous determination of volatile organic compounds (VOCs) and carbonyls in the mainstream cigarette smoke using a sorbent cartridge at ambient temperature without the traditional cryogenic impinger. A sorbent cartridge is installed between intake filter and the pump of the smoking machine. Collection of cigarette mainstream smoke is performed according to the Canadian Intense regime or the ISO regime. As adsorbent, Carboxen 572 (CX-572) is the most suitable for collection of VOCs and carbonyls in the mainstream cigarette smoke. Elution of VOCs and carbonyls from CX-572 is performed by the two-step elution with carbon disulfide and methanol. VOCs are eluted by first elution with carbon disulfide and carbonyls are eluted by second elution with methanol. For VOCs, a portion of eluate is analyzed by gas chromatography-mass spectrometry. For carbonyls, a portion of eluate is derivatized with enriched 2,4-dinitrophenylhydrazine solution and analyzed by high-performance liquid chromatography. Measurement values by CX-572 cartridge method are very close to those obtained by traditional impinger method except for 2-butanone. Impinger methods use 2,4-dinitrophenylhydrazine solution containing 50% water and 2-butanone-DNPhydrazone may be hydrolyzed with water. In the CX-572 method, the hydrolysis of 2-butanone is prevented because the eluate solution contains no water. CX-572 method can measure cigarette smoke resulting from not only one whole cigarette but also from one puff volume because of its high sensitivity and simple operation.

Genome-wide association studies of maximum number of drinks

Maximum number of drinks (MaxDrinks) defined as "Maximum number of alcoholic drinks consumed in a 24-h period" is an intermediate phenotype that is closely related to alcohol dependence (AD). Family, twin and adoption studies have shown that the heritability of MaxDrinks is approximately 0.5. We conducted the first genome-wide association (GWA) study and meta-analysis of MaxDrinks as a continuous phenotype. 1059 individuals were from the Collaborative Study on the Genetics of Alcoholism (COGA) sample and 1628 individuals were from the Study of Addiction - Genetics and Environment (SAGE) sample. Family sample with 3137 individuals was from the Australian twin-family study of alcohol use disorder (OZALC). Two population-based Caucasian samples (COGA and SAGE) with 1 million single-nucleotide polymorphisms (SNPs) were used for gene discovery and one family-based Caucasian sample was used for replication. Through meta-analysis we identified 162 SNPs associated with MaxDirnks (p < 10(-4)). The most significant association with MaxDrinks was observed with SNP rs11128951 (p = 4.27 × 10(-8)) near SGOL1 gene at 3p24.3. Furthermore, several SNPs (rs17144687 near DTWD2, rs12108602 near NDST4, and rs2128158 in KCNB2) showed significant associations with MaxDrinks (p < 5 × 10(-7)) in the meta-analysis. Especially, 8 SNPs in DDC gene showed significant associations with MaxDrinks (p < 5 × 10(-7)) in the SAGE sample. Several flanking SNPs in above genes/regions were confirmed in the OZALC family sample. In conclusions, we identified several genes/regions associated with MaxDrinks. These findings can improve the understanding about the pathogenesis of alcohol consumption phenotypes and alcohol-related disorders.