Alcohol, tobacco, and diet in relation to esophageal cancer: the Shanghai Cohort Study

Urinary levels of tobacco-specific nitrosamine metabolites in relation to lung cancer development in two prospective cohorts of cigarette smokers

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and its glucuronides (sum of which is denoted as total NNAL) are metabolites of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). NNK and NNAL can induce lung cancer in laboratory animals but human data are limited. The association between prediagnostic levels of urinary total NNAL and risk of lung cancer development was evaluated in two prospective cohorts of Chinese cigarette smokers. We conducted a nested case-control study involving 246 cases of incident lung cancer and 245 cohort controls who were individually matched to the index cases by age, gender, neighborhood of residence at cohort enrollment, and date of urine collection. Urinary levels of total NNAL were significantly associated with risk of lung cancer in a dose-dependent manner. Relative to the lowest tertile, risks associated with the second and third tertiles of total NNAL were 1.43 [95% confidence interval (95% CI), 0.86-2.37] and 2.11 (95% CI, 1.25-3.54), respectively (P for trend=0.005) after adjustment for self-reported smoking history and urinary total cotinine. Smokers in the highest tertiles of urinary total NNAL and total cotinine exhibited a 8.5-fold (95% CI, 3.7-19.5) increased risk for lung cancer relative to smokers with comparable smoking history but possessing the lowest tertiles of urinary total NNAL and total cotinine. Findings of the present study directly link NNK exposure to lung cancer development in humans.

The activity of class I, II, III, and IV alcohol dehydrogenase (ADH) isoenzymes and aldehyde dehydrogenase (ALDH) in esophageal cancer

BACKGROUND/AIMS

Ethanol consumption is associated with an increased risk of esophageal cancer. The carcinogenic compound is acetaldehyde, the product of ethanol metabolism. Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are the main enzymes involved in ethanol metabolism, which leads to generation of acetaldehyde. In this study the activity of ADH isoenzymes and ALDH in esophageal cancer were compared with the activity in normal tissue.

METHODS

For measurement of the activity of class I and II ADH isoenzymes and ALDH activity fluorimetric methods were employed. Total ADH activity and activity of class III and IV isoenzymes was measured by the photometric method. Samples were taken from 59 esophageal cancer patients (27 adenocarcinoma, 32 squamous cell cancer).

RESULTS

The total activity of ADH and activity of class IV ADH were significantly higher in cancer cells than in healthy tissues. The other tested classes of ADH showed a tendency toward higher activity in cancer than in normal cells. Differences between the activity of enzymes of drinkers and non-drinkers in both cancer and healthy tissue were not significant.

CONCLUSION

Increased ADH IV activity may be a factor intensifying carcinogenesis, because of the increased ability to form acetaldehyde from ethanol.

Overexpression of astrocyte elevated gene-1 (AEG-1) is associated with esophageal squamous cell carcinoma (ESCC) progression and pathogenesis

Astrocyte elevated gene-1 (AEG-1), upregulated in various types of human cancers, has been reported to be associated with the carcinogenesis of human cancer. However, the functional significance of AEG-1 in human esophageal squamous cell carcinoma (ESCC) remains unknown. In the present study, we showed the expression of AEG-1 was markedly upregulated in esophageal cancer cell lines and surgical ESCC specimens at both transcriptional and translational levels. Immunohistochemical analysis revealed that 80 of 168 (47.6%) paraffin-embedded archival ESCC specimens exhibited high levels of AEG-1 expression. Statistical analysis suggested the upregulation of AEG-1 was significantly correlated with the clinical staging of the ESCC patients (P = 0.001), T classification (P = 0.002), N classification (P = 0.034), M classification (P = 0.021) and histological differentiation (P = 0.035) and those patients with high AEG-1 levels exhibited shorter survival time (P < 0.001). Multivariate analysis indicated that AEG-1 expression might be an independent prognostic indicator of the survival of patients with ESCC. Furthermore, we found that ectopic expression of AEG-1 in ESCC cells could significantly enhance cell proliferation and anchorage-independent growth ability. Conversely, silencing AEG-1 by short hairpin RNAi caused an inhibition of cell growth and anchorage-independent growth ability on soft agar. Moreover, we demonstrated that the upregulation of AEG-1 could reduce the expression of p27(Kip1) and induce the expression of cyclin D1 through the AKT/FOXO3a pathway. Our findings suggest that the AEG-1 protein is a valuable marker of ESCC progression and that the upregulation of AEG-1 plays an important role in the development and pathogenesis of human ESCC.

Tannin extracted from Sumac inhibits vascular smooth muscle cell migration

BACKGROUND

Vascular smooth muscle cell (VSMC) migration is integral in the pathogenesis of atherosclerosis. Sumac (Rhus coriaria) berries are believed to have atheroprotective effects. Therefore, Sumac, which is a rich source of tannin antioxidants, was tested for its capacity to inhibit VSMC migratory activity.

MATERIALS & METHODS

Tannin was extracted and purified from ground Sumac. Cultured rat carotid VSMCs were treated with different concentrations of tannin. After 10 days of tannin treatment, VSMC migratory activity in response to platelet-derived growth factor-BB was measured by transmembrane migration assay. An equal number of VSMCs was loaded on top of the inserts and at the bottom of the wells. After fixation and staining, cells migrating through the inserts and cells seeded at the bottom of the wells were counted.

RESULTS

A significant reduction (62%) of VSMC migration was evident in tannin-treated cells. To rule out any possible toxicity and cell death, cells at the bottom of the wells were also counted. No difference between the tannin-treated group and the controls was observed in the number of cells seeded at the bottom of the wells.

CONCLUSION

Our data suggest that tannin extracted from Sumac possesses potent antimigratory activity. Sumac may have potential for the prevention or treatment of atherosclerosis and its clinical manifestations. Further experiments, especially in vivo, are required to examine the atheroprotective effect of Sumac.