Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.

Chronic ethanol exposure of human pancreatic normal ductal epithelial cells induces cancer stem cell phenotype through SATB2

The incidence of pancreatic cancer is on the rise. Risk factors for pancreatic cancer include alcohol toxicity and metabolic conditions such as obesity, hypertension, dyslipidaemia, insulin resistance and type 2 diabetes. However, the molecular mechanism by which chronic alcohol consumption contributes to pancreatic cancer is not well understood. The purpose of the study was to demonstrate the effects of long-term chronic ethanol exposure on the transformation of human pancreatic normal ductal epithelial (HPNE) cells. Our data showed that ethanol-transformed HPNE cells were more progressively transformed exhibiting spheroids and colonies, and anchorage-independent growth. These transformed cells contained high levels of reactive oxygen species and induced SATB2 expression. Furthermore, during ethanol-induced cellular transformation, cells gained the phenotypes of cancer stem cells (CSCs) by expressing pluripotency maintaining factors (Oct4, Sox2, cMyc and KLF4) and stem cell markers (CD24, CD44 and CD133). Ethanol-induced SATB2 can bind to the promoters of KLF4, Oct4, cMyc, Sox2, Bcl-2 and XIAP genes. Suppression of SATB2 expression in ethanol-transformed HPNE cells inhibited cell proliferation, colony formation and markers of CSCs and pluripotency. These data suggest that chronic alcohol consumption may contribute toward the development of pancreatic cancer by converting HPNE cells to cancer stem-like cells.

Alcohol consumption and the risks of adenocarcinoma and squamous cell carcinoma of the esophagus

BACKGROUND AND AIMS

Alcohol has been declared a carcinogen for cancers of the esophagus, although the evidence relates largely to the squamous subtype. Evidence for an effect on adenocarcinomas is scant and inconsistent.

METHODS

We compared nationwide samples of patients with esophageal adenocarcinoma (EAC) (n=365) or esophagogastric junction adenocarcinoma (EGJAC) (n=426) or esophageal squamous cell carcinoma (ESCC) (n=303) with controls sampled from a population register (n=1580). We used generalized additive models to assess nonlinear effects of self-reported alcohol intake on cancer risk, and calculated odds ratios (ORs) and 95% confidence intervals (CIs) using multivariate logistic and piecewise regression.

RESULTS

We observed no association between average weekly alcohol intake and EAC or EGJAC risk. For ESCC, the relationship with alcohol was nonlinear. At intakes of less than 170 g/wk there was no significant association; at greater than this level, there was a significant linear effect (OR, 1.03; 95% CI, 1.02-1.05 per 10 g alcohol/wk). For ESCC, but not EAC or EGJAC, a statistically significant multiplicative interaction between smoking and alcohol was observed (P=.02). In analyses by beverage type, ESCC risks, but not EAC or EGJAC, increased linearly with beer intake (OR, 1.05; 95% CI, 1.04-1.07). Those who drank modest levels of wine (<50-90 g/wk) or port or spirits (<10-20 g/wk) had significantly lower risks of all 3 cancers than nondrinkers; higher intakes were associated with increased risks of ESCC only.

CONCLUSIONS

Alcohol intake above the recommended US dietary guidelines significantly increases the risk of ESCC, but not EAC or EGJAC. Smoking modifies the effect of alcohol intake on ESCC risk.

Suicides among cancer patients in Estonia: a population-based study

The objective of this study was to determine the suicide risk among cancer patients in Estonia. This risk was examined in a cohort of 65,419 persons diagnosed with cancer in 1983-1998. Standardised mortality ratios (SMR) were calculated using the suicide rates of the population of Estonia as a reference. During 192,078 person-years of follow-up between 1983 and 2000, 197 suicides occurred in the cohort. An increased suicide risk was found for men (SMR=1.73; 95% Confidence Interval (CI) 1.45-2.01), but not for women (SMR=0.50; 95% CI 0.37-0.66). Men had the highest risk 90-179 days following their diagnosis (SMR=4.27; 95% CI 2.81-6.21). During this time interval, among men, the risk was more pronounced for cancers of the oesophagus (SMR=35.63; 95% CI 9.71-91.22) and pancreas (SMR=14.53; 95% CI 1.76-52.50). This study provides further evidence that cancer is a risk factor for suicide, at least in men.

Do the ethanol metabolizing enzymes modify the relationship between alcohol consumption and blood pressure?

BACKGROUND

Several cross-sectional studies have examined whether the relationship between alcohol consumption and blood pressure (alcohol-BP relationship) differs among individuals with different aldehyde dehydrogenase-2 (ALDH2) genotypes, but few studies have examined the association with alcohol dehydrogenase-2 (ADH2), and those have yielded inconsistent results. We examined the potential modulatory effects of ADH2 and ALDH2 genotypes on the alcohol-BP relationship in a cross-sectional sample of a Japanese rural community.

METHODS AND RESULTS

The study subjects were 335 randomly selected men aged 40-69 years, who lived in Shiso, a Japanese rural county, in 1999 or 2000. The genetic polymorphisms of ADH2 and ALDH2 were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. The frequencies of ADH21/21 (wild-type), 21/22 (superactive heterozygotes), and 22/22 (superactive homozygotes) were 8.4, 34.9 and 56.7%, respectively; and those of ALDH21/21 (wild-type), 21/22 (inactive heterozygotes), and 22/22 (inactive homozygotes) were 52.8, 40.9, and 6.3%, respectively. A multiple linear regression analysis showed that the relationship between alcohol consumption and diastolic blood pressure was significantly stronger in men with ADH21/21 than those with ADH21/22 or 22/22 (adjusted regression coefficient = 0.0392 versus 0.0113 mmHg for + 1 g ethanol/week, P for difference in slope = 0.018). The strength of the alcohol-BP relationship was similar in all of the ALDH2 genotype groups.

CONCLUSION

The alcohol-BP relationship was significantly stronger in men with ADH21/21 than in men with ADH21/22 or 22/22 in this Japanese rural population. This finding was exactly the opposite of what one previous study suggested.

A case-control study of childhood leukemia in Woburn, Massachusetts: the relationship between leukemia incidence and exposure to public drinking water

A 1981 Massachusetts Department of Public Health study confirmed a childhood leukemia cluster in Woburn, Massachusetts. Our follow-up investigation attempts to identify factors potentially responsible for the cluster. Woburn has a 130-year industrial history that resulted in significant local deposition of tannery and chemical manufacturing waste. In 1979, two of the city's eight municipal drinking water wells were closed when tests identified contamination with solvents including trichloroethylene. By 1986, 21 childhood leukemia cases had been observed (5.52 expected during the seventeen year period) and the case-control investigation discussed herein was begun. Nineteen cases and 37 matched controls comprised the study population. A water distribution model provided contaminated public water exposure estimates for subject residences. Results identified a non-significant association between potential for exposure to contaminated water during maternal pregnancy and leukemia diagnosis, (odds ratio = 8.33, 95% CI 0.73-94.67). However, a significant dose-response relationship (P < 0.05) was identified for this exposure period. In contrast, the child's potential for exposure from birth to diagnosis showed no association with leukemia risk. Wide confidence intervals suggest cautious interpretation of association magnitudes. Since 1986, expected incidence has been observed in Woburn including 8 consecutive years with no new childhood leukemia diagnoses.

Tobacco and alcohol consumption: impact on other cardiovascular and cancer risk factors in a southern European Mediterranean population

Tobacco and alcohol consumption are strongly related to other cardiovascular and cancer risk factors. The aim of the present study was to analyse the association of nutrient intake, blood lipid variables and leisure-time physical activity with tobacco and alcohol consumption status. Participants were recruited in a cross-sectional population-based survey, including cardiovascular risk factor measurements and evaluation of physical activity and diet intake in a Mediterranean population (n 1748). Multiple linear regression analysis, adjusted for several confounders, showed a direct association of saturated fatty acids (g and % total energy intake), dietary cholesterol intakes and serum triacylglycerol with smoking. An inverse association was observed for smoking and unsaturated fatty acids (% energy intake), vitamin C, alpha-tocopherol and beta-carotene intakes, leisure-time physical activity and HDL-cholesterol. These associations were not observed for alcohol drinking. After adjusting for the confounders earlier mentioned, low dietary intakes of vitamin C and dietary fibre were more likely in heavy-smokers as compared with non-smokers (odds ratio 1.74 (95 % CI 1.07, 2.73) and 1.94 (95 % CI 1.29, 2.92) of low vitamin C (<60 mg/d) and dietary fibre intakes (<10 g/d) respectively). Alcohol consumption was directly associated with HDL-cholesterol and triacylglycerol, and attenuated the effects of smoking on HDL-cholesterol. These results suggest that the dietary intake of fibre and several antioxidant components of the Mediterranean diet is reduced in smokers, who also show an adverse lipid profile. However, the worst triacylglycerol levels are associated with the combination of heavy smoking and heavy alcohol drinking. Moderate alcohol consumption was not associated with an unhealthy diet pattern or adverse lipid profile. The health benefits of the Mediterranean diet appear to be strongly counteracted by smoking.

Ethanol modulates the growth of human breast cancer cells in vitro

The role of ethanol or its metabolites on breast neoplasm has not been characterized. We hypothesized that ethanol may alter the growth rate of human breast tumor epithelial cells by modulating putative growth-promoting signaling pathways such as p44/42 mitogen-activated protein kinases (MAPKs). The MCF-7 cell line, considered a suitable model, was used in these studies to investigate the effects of ethanol on [(3)H]thymidine incorporation, cell number, and p44/42 MAPK activities in the presence or absence of a MAPK or extracellular signal-regulated kinase ERK-1, and (MEK1) inhibitor (PD098059). Treatment of MCF-7 cells with a physiologically relevant concentration of ethanol (0.3% or 65 mM) increased p44/42 activities by an average of 400% (P < 0.02), and subsequent cell growth by 200% (P < 0.05) in a MEK1 inhibitor (PD098059)-sensitive fashion, thus suggesting that the Ras/MEK/MAPK signaling pathways are crucial for ethanol-induced MCF-7 cell growth.

Defining alcohol-related fatal medical conditions for social-cost studies in western societies: an update of the epidemiological evidence

OBJECTIVES

To elaborate a state-of-the-art list of alcohol-related fatal medical conditions for future social-cost studies in Western societies.

METHODS

Three major social-cost studies were compared with regard to their respective section on fatal health effects attributable to long-term as well as short-term use of alcohol. On discordant conditions, a systematic literature search was conducted in the Medline and ETOH databases.

RESULTS

There is no consensus between social-cost studies with respect to alcohol-related causes of mortality. Based on the recent epidemiological evidence on alcohol and health, this paper suggests an up-to-date list of fatal medical conditions for which the causal relationship has been established with sufficient scientific evidence. A further investigation is needed, however, to reestimate relative risks by meta-analysis.

CONCLUSIONS

Evaluating new epidemiological evidence regularly is necessary for the purpose of up-to-date social-cost studies.

Promitogenic effects of ethanol, methanol, and ethanolamine in insulin-treated fibroblasts

The zinc-dependent potentiating effect of ethanol (EtOH) on insulin-stimulated DNA synthesis was studied with a focus on the possible site of EtOH action and the ability of other alcohols to elicit similar promitogenic effects. In serum-starved (27 hr) NIH 3T3 fibroblasts, 200-300 mM methanol (MeOH) and 0.1-1.5 mM ethanolamine (Etn), but not 3- to 9-carbon normal alcohols, enhanced the effect of insulin on DNA synthesis to varying extents. The promitogenic effects of EtOH and MeOH, but not that of Etn, required the presence of 15-25 microM zinc. The potentiating effects of Etn were enhanced by 5 mM choline (Cho) and inhibited by 1-3 mM hemicholinium-3 (HC-3), an inhibitor of Cho transporter and Cho kinase. In the presence of 15 microM zinc, 40 mM EtOH, which had no effect on its own, inhibited the potentiating effects of Cho and enhanced the inhibitory effects of HC-3 on synergistic stimulation of DNA synthesis by Etn and insulin. On the other hand, both Cho and HC-3 partially inhibited the promitogenic effect of 80 mM EtOH in the presence of 25 microM zinc. After a 10-min incubation, EtOH decreased the amount of cell-associated [(14)C]Cho in the absence but not in the presence of HC-3. After a 40-min incubation, Cho (5 mM) partially inhibited the cellular uptake as well as the metabolism of [(14)C]Etn. Whereas after the 40-min incubation 80 mM EtOH had no effects on Etn metabolism, in the absence of Cho it decreased the amount of cell-associated [(14)C]Etn. However, EtOH had no detectable effects on cell association of [(14)C]Etn after the 10-min incubation. The results suggest that in NIH 3T3 fibroblasts EtOH is a remarkably specific promitogen, and that it may act via a cell membrane site(s), also regulated by Cho (agonist) and HC-3 (antagonist), which can influence membrane binding and the promitogenic activity of Etn.

Ethanol has multiple effects on DNA synthesis in fibroblasts depending on the presence of secreted growth regulators and zinc as well as the level of protein kinase C activation

Earlier we showed that in serum-starved (27 h), washed mouse fibroblasts and other cell lines 40-80 mM concentrations of ethanol (EtOH) potentiate, in a zinc (Zn2+)-dependent manner, the combined stimulatory effects of calcium (Ca2+) and insulin (Ins) on DNA synthesis. We now report that the promitogenic EtOH effects require removal of the used medium at least 6 h prior to treatments with EtOH, Zn2+, and Ins. If serum-starved (27 h) cells were continuously incubated for another 18-h period without replacing the medium, a secreted cellular factor moderately enhanced the mitogenic effect of Ins and simultaneously blocked the potentiating effect of EtOH on DNA synthesis measured during the last hour of treatments. However, the presence of Ca2+ (2.8 mM) plus Zn2+ (25 microM) or 25-300 nM phorbol 12-myristate 13-acetate (PMA) during the serum starvation period partially restored the promitogenic effect of EtOH. The PMA effect was blocked by the protein kinase C (PKC) inhibitor GF 109203X added for the second (18 h) period. Even at 300 nM, PMA failed to fully downregulate PKC-alpha, the major PKC isoform, over a 28-h period, suggesting that an activated PKC enzyme was involved in the restoration of EtOH effect. When EtOH (40-80 mM) was added for the entire serum starvation period and the incubations were continued for 18 h without removing the medium, EtOH inhibited both the combined actions of Ins and cellular factor as well as the promoting effect of newly added EtOH on Ins-dependent DNA synthesis. Coaddition of Zn2+ and PMA with EtOH prevented these inhibitory effects of EtOH. The results indicate that in mouse fibroblasts EtOH can both enhance and inhibit Ins-dependent DNA synthesis depending on the timing of EtOH treatment as well as the presence of Zn2+, cellular factors, and activators of the PKC system.

Incidence of cancer among welders and other shipyard workers with information on previous work history

The incidence of cancer among 4480 shipyard workers, including 861 welders, was investigated for a potential relationship between exposure to welding fumes and lung cancer. A subcohort of 3150 workers with information on previous work history was studied separately. This investigation is a historical prospective cohort study. Environmental air samples were collected in 1973, 1977, and 1989. Information on smoking habits was surveyed in 1976 and 1984. The employment work histories were collected from the personnel register. There were 411 observed cancers of all sites versus 387.5 expected, and 45 cases of lung cancer versus 51.3 expected. Nine cases of lung cancer were found among the welders versus 7.1 expected. Among 310 former seamen with welding experience, there was 1 case of lung cancer versus 2.1 expected. These shipyard workers showed no excess risk of lung cancer. Tobacco smoking and asbestos exposure are potential confounders in the study. There was no clear relationship between exposure to welding fumes and lung cancer, but welders with the longest experience had a relative risk of 1.9 for lung cancer. The differences in lung cancer incidence among the different shipyard workers could not be attributed to differences in recruitment patterns or previous work history.