• Androgen deprivation induces human prostate epithelial neuroendocrine differentiation of androgen-sensitive LNCaP cells.

      Yuan, Ta-Chun; Veeramani, Suresh; Lin, Fen-Fen; Kondrikou, Dmitry; Zelivianski, Stanislav; Igawa, Tsukasa; Karan, Dev; Batra, Surinder K.; Lin, Ming-Fong (2006-03)
      Neuroendocrine (NE) cells are the minor cell populations in normal prostate epithelial compartments. During prostate carcinogenesis, the number of NE cells in malignant lesions increases, correlating with its tumorigenicity and hormone-refractory growth. It is thus proposed that cancerous NE cells promote prostate cancer (PCa) cell progression and its androgen-independent proliferation, although the origin of the cancerous NE cells is not clear. To investigate the role of cancerous NE cells in prostate carcinogenesis, we characterized three NE subclone cell lines-NE-1.3, NE-1.8 and NE-1.9, which were transdifferentiated from androgen-sensitive human PCa LNCaP cells by culturing in an androgen-depleted environment, resembling clinical androgen-ablation therapy. These subclone cells acquire many features of NE cells seen in clinical prostate carcinomas, for example exhibiting a neuronal morphology and expressing multiple NE markers, including neuron-specific enolase, chromogranin B, neurotensin, parathyroid hormone-related peptide, and to a lesser degree for chromogranin A, while lacking androgen receptor (AR) or prostate specific antigen (PSA) expression. These cells represent terminally differentiated stable cells because after 3 months of re-culturing in a medium containing androgenic activity, they still retained the NE phenotype and expressed NE markers. Despite these NE cells having a slow growth rate, they readily developed xenograft tumors. Furthermore, media conditioned by these NE cells exhibited a stimulatory effect on proliferation and PSA secretion by LNCaP cells in androgen-deprived conditions. Additionally, we found that receptor protein tyrosine phosphatase alpha plays a role in upregulating multiple NE markers and acquiring the NE phenotype. These NE cells thus represent cancerous NE cells and could serve as a useful cell model system for investigating the role of cancerous NE cells in hormone-refractory proliferation of PCa cells.
    • Chemopreventive effects of rofecoxib and folic acid on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine in rats.

      Fei, Su Juan; Xiao, Shu Dong; Peng, Yan Shen; Chen, Xiao Yu; Shi, Yao (2006)
      OBJECTIVES: Epidemiological and experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) are chemopreventive agents of gastrointestinal cancers, but few studies on gastric cancer have been carried out. A decrease in folic acid supplement and subsequent DNA hypomethylation are related to gastrointestinal cancers, and it has been shown that high-dose folic acid may interfere with gastric carcinogenesis in dogs. The objective of this study was to investigate the effects of rofecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, and folic acid on the chemoprevention of gastric cancer induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Wistar rats, and to evaluate the cell proliferation of gastric mucosa in different experimental groups. METHODS: Eighty male Wistar rats were randomly divided into five groups (16 rats in each group). In the control group, the rats were given pure water and basal diet. In the MNNG group, the rats received MNNG in drinking water (100 mg/L) and basal diet. In the MNNG + low-dose rofecoxib group, the rats were given MNNG and rofecoxib 5 mg/kg per day with basal diet. In the MNNG + high-dose rofecoxib group, the rats were given MNNG and rofecoxib 15 mg/kg per day with basal diet. In the MNNG + folic acid group, the rats were given MNNG and folic acid 5 mg/kg per day with basal diet. The experiment was terminated at 50 weeks, and all rats were killed. Blood samples of 3 mL were obtained for measurement of serum folic acid concentrations in the control group, the MNNG group and the MNNG + folic acid group by using chemiluminescent method. The stomach was removed from all rats for histopathological examination and immunohistochemical study. Proliferating cell nuclear antigen (PCNA) expression in gastric epithelial cells was also determined. RESULTS: In the MNNG group, five of 11 rats (45.5%) developed gastric cancer, while in all other four groups no gastric cancer was found (P < 0.05). The positivity rate of PCNA expression in the cancerous tissues was significantly higher than that in the non-cancerous tissues (80.0%vs 14.1%, P < 0.05). The positivity rate of PCNA expression in the gastric mucosal cells of the MNNG group was significantly higher than that in the other four groups. The mean serum folic acid concentration of rats was significantly higher in the MNNG + folic acid group (193.70 +/- 60.73 ng/mL) than those in the control group (84.21 +/- 25.26 ng/mL) and the MNNG group (72.27 +/- 16.70 ng/mL, P < 0.05). It was shown that both low- and high-dose rofecoxib as well as folic acid interfered with the development of gastric cancer induced by MNNG in Wistar rats. CONCLUSIONS: The results indicate that rofecoxib as well as folic acid interferes with gastric carcinogenesis induced by MNNG in Wistar rats, and the suppression of gastric cell proliferation may play a crucial role in the chemoprevention of gastric cancer by rofecoxib and folic acid. The higher serum folic acid concentration of rats may play an important role in the prevention of gastric cancer.
    • Dietary patterns and risk of squamous-cell carcinoma and adenocarcinoma of the esophagus and adenocarcinoma of the gastric cardia: a population-based case-control study in Sweden.

      Bahmanyar, Shahram; Ye, Weimin (2006)
      We conducted a large population-based case-control study in Sweden to examine the association of dietary patterns and the development of cancers from the esophagus or gastroesophageal junction. In total 185 patients with esophageal adenocarcinoma, 165 with esophageal squamous-cell carcinoma, 258 with gastric cardia adenocarcinoma, and 815 randomly selected population controls underwent face-to-face interviews. Exploratory factor analysis was used to identify possible dietary patterns. Multivariate logistic regression with adjustments for age, sex, years of education, body mass index, physical activity, symptomatic gastroesophageal reflux, smoking, and total energy intake was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs). We identified three major dietary patterns in this population, for example, "healthy diet" (high in vegetables, tomato, fruits, fish, and poultry), "Western diet" (high in processed meat, red meat, sweets, high-fat dairy, and high-fat gravy), and "alcohol drinker" (high in intakes of beer, liquor, and French fries). We found that a healthy diet tended to moderately decrease the risk of all three cancers under study, although none of the associations was statistically significant. A high score of Western diet was associated with increased risks of gastric cardia adenocarcinoma (high 3rd tertile vs. low 1st quartile, OR = 1.8, 95% CI = 1.1-2.9, P for trend = 0.04) and esophageal adenocarcinoma (high 3rd tertile vs. low 1st tertile, OR = 1.6, 95% CI = 0.9-3.1, P for trend = 0.13), whereas a dietary pattern characterized by high beer and liquor intake (alcohol drinker) significantly increased the risk of squamous-cell carcinoma of the esophagus (3rd tertile vs. low 1st tertile, OR = 3.5, 95% CI = 1.9-6.3, P for trend < 0.0001). Our study confirms the important role of diet in the carcinogenesis of esophageal and cardia cancer.
    • The effects of short-chain fatty acids on colon epithelial proliferation and survival depend on the cellular phenotype.

      Comalada, Monica; Bailon, Elvira; de Haro, Oscar; Lara-Villoslada, Federico; Xaus, Jordi; Zarzuelo, Antonio; Galvez, Julio (2006-08)
      PURPOSE: The short-chain fatty acids (SCFA) are produced via anaerobic bacterial fermentation of dietary fiber within the colonic lumen. Among them, butyrate is thought to protect against colon carcinogenesis. However, few studies analyze the effects of butyrate, and other SCFA, on normal epithelial cells and on epithelial regeneration during disease recovery. Since there are controversial in vitro studies, we have explored the effects of SCFA on different biological processes. METHODS: We used both tumoral (HT-29) and normal (FHC) epithelial cells at different phenotypic states. In addition, we analyzed the in vivo activity of soluble dietary fiber and SCFA production in the proliferation rate and regeneration of intestinal epithelial cells. RESULTS: The effect of butyrate on epithelial cells depends on the phenotypic cellular state. Thus, in nondifferentiated, high proliferative adenocarcinoma cells, butyrate significantly inhibited proliferation while increased differentiation and apoptosis, whereas other SCFA studied did not. However, in normal cells or in differentiated cultures as well as in in vivo studies, the normal proliferation and regeneration of damaged epithelium is not affected by butyrate or SCFA exposure. CONCLUSION: Although butyrate could exert antiproliferative effects in tumor progression, its production is safe and without consequences for the normal epithelium growth.
    • Endogenous versus exogenous exposure to N-nitroso compounds and gastric cancer risk in the European Prospective Investigation into Cancer and Nutrition (EPIC-EURGAST) study.

      Jakszyn, Paula; Bingham, Sheila; Pera, Guillem; Agudo, Antonio; Luben, Robert; Welch, Ailsa; Boeing, Heiner; Del Giudice, Giuseppe; Palli, Domenico; Saieva, Calogero; et al. (2006-07)
      The risk of gastric cancer (GC) associated with dietary intake of nitrosodimethylamine (NDMA) and endogenous formation of nitroso compounds (NOCs) was investigated in the European Prospective Investigation into Cancer and Nutrition (EPIC). The study included 521,457 individuals and 314 incident cases of GC that had occurred after 6.6 average years of follow-up. An index of endogenous NOC (ENOC) formation was estimated using data of the iron content from meat intake and faecal apparent total NOC formation according to previous published studies. Antibodies to Helicobacter pylori and vitamin C levels were measured in a sub-sample of cases and matched controls included in a nested case-control within the cohort. Exposure to NDMA was < 1 microg on average compared with 93 mug on average from ENOC. There was no association between NDMA intake and GC risk (HR, 1.00; 95% CI, 0.7-1.43). ENOC was significantly associated with non-cardia cancer risk (HR, 1.42; 95% CI, 1.14-1.78 for an increase of 40 microg/day) but not with cardia cancer (HR, 0.96; 95% CI, 0.69-1.33). Although the number of not infected cases is low, our data suggest a possible interaction between ENOC and H.pylori infection (P for interaction = 0.09). Moreover, we observed an interaction between plasma vitamin C and ENOC (P < 0.02). ENOC formation may account for our previously reported association between red and processed meat consumption and gastric cancer risk.
    • Genotoxic effects of myosmine in a human esophageal adenocarcinoma cell line.

      Vogt, Sarah; Fuchs, Katharina; Richter, Elmar (2006-05-01)
      The incidence of esophageal adenocarcinoma is rapidly rising in Western populations. Gastroesophageal reflux disease (GERD) is thought to be one of the most important risk factors. However, the mechanisms by which GERD enhances tumor formation at the gastroesophageal junction are not well understood. Myosmine is a tobacco alkaloid which has also a wide spread occurrence in human diet. It is readily activated by nitrosation and peroxidation giving rise to the same hydroxypyridylbutanone-releasing DNA adducts as the esophageal carcinogen N'-nitrosonornicotine. Therefore, the genotoxicity of myosmine was tested in a human esophageal adenocarcinoma cell line (OE33). DNA damage was assessed by single-cell gel electrophoresis (Comet assay). DNA strand breaks, alkali labile sites and incomplete excision repair were expressed using the Olive tail moment (OTM). The Fapy glycosylase (Fpg) enzyme was incorporated into the assay to reveal additional oxidative DNA damage. DNA migration was determined after incubation of the cells for 1-24h. Under neutral conditions high myosmine concentrations of 25-50mM were necessary to elicit a weak genotoxic effect. At pH 6 genotoxicity was clearly enhanced giving a significant increase of OTM values at 5mM myosmine. Lower pH values could not be tested because of massive cytotoxicity even in the absence of myosmine. Co-incubation of 25 mM myosmine with 1mM H(2)O(2) for 1h significantly enhanced the genotoxicity of H(2)O(2) but not the oxidative lesions additionally detected with the Fpg enzyme. In the presence of the peroxynitrite donor 3-morpholinosydnonimine (SIN-1) a dose-dependent significant genotoxic effect was obtained with 1-10mM myosmine after 4h incubation. NS-398, a selective inhibitor of cyclooxygenase 2, did not affect the SIN-1 stimulated genotoxicity of myosmine. Finally, the 23 h repair of N-methyl-N'-nitro-N-nitrosoguanidine-induced DNA lesions was significantly inhibited in the presence of 10mM myosmine. In conclusion, myosmine exerts significant genotoxic effects in esophageal cells under conditions which may prevail in GERD such as increased oxidative and nitrosative stress resulting from chronic inflammation.
    • Meat intake and risk of stomach and esophageal adenocarcinoma within the European Prospective Investigation Into Cancer and Nutrition (EPIC).

      González, Carlos A.; Jakszyn, Paula; Pera, Guillem; Agudo, Antonio; Bingham, Sheila; Palli, Domenico; Ferrari, Pietro; Boeing, Heiner; del Giudice, Giuseppe; Plebani, Mario; et al. (2006-03-01)
      BACKGROUND: Dietary factors are thought to have an important role in gastric and esophageal carcinogenesis, but evidence from cohort studies for such a role is lacking. We examined the risks of gastric cancer and esophageal adenocarcinoma associated with meat consumption within the European Prospective Investigation Into Cancer and Nutrition (EPIC) cohort. METHODS: A total of 521,457 men and women aged 35-70 years in 10 European countries participated in the EPIC cohort. Dietary and lifestyle information was collected at recruitment. Cox proportional hazard models were used to examine associations between meat intake and risks of cardia and gastric non-cardia cancers and esophageal adenocarcinoma. Data from a calibration substudy were used to correct hazard ratios (HRs) and 95% confidence intervals (CIs) for diet measurement errors. In a nested case-control study, we examined interactions between Helicobacter pylori infection status (i.e., plasma H. pylori antibodies) and meat intakes. All statistical tests were two-sided. RESULTS: During a mean follow-up of 6.5 years, 330 gastric adenocarcinoma and 65 esophageal adenocarcinomas were diagnosed. Gastric non-cardia cancer risk was statistically significantly associated with intakes of total meat (calibrated HR per 100-g/day increase = 3.52; 95% CI = 1.96 to 6.34), red meat (calibrated HR per 50-g/day increase = 1.73; 95% CI = 1.03 to 2.88), and processed meat (calibrated HR per 50-g/day increase = 2.45; 95% CI = 1.43 to 4.21). The association between the risk of gastric non-cardia cancer and total meat intake was especially large in H. pylori-infected subjects (odds ratio per 100-g/day increase = 5.32; 95% CI = 2.10 to 13.4). Intakes of total, red, or processed meat were not associated with the risk of gastric cardia cancer. A positive but non-statistically significant association was observed between esophageal adenocarcinoma cancer risk and total and processed meat intake in the calibrated model. In this study population, the absolute risk of development of gastric adenocarcinoma within 10 years for a study subject aged 60 years was 0.26% for the lowest quartile of total meat intake and 0.33% for the highest quartile of total meat intake. CONCLUSION: Total, red, and processed meat intakes were associated with an increased risk of gastric non-cardia cancer, especially in H. pylori antibody-positive subjects, but not with cardia gastric cancer.
    • O6-alkylguanine-DNA alkyltransferase gene polymorphisms and the risk of primary lung cancer.

      Chae, Myung Hwa; Jang, Jin-Sung; Kang, Hyo-Gyoung; Park, Jae Hyung; Park, Jung Min; Lee, Won Kee; Kam, Sin; Lee, Eung Bae; Son, Ji-Woong; Park, Jae Yong (2006-04)
      O6-alkylguanine-DNA alkyltransferase (AGT) plays an important role in the repair of O6-alkylguanine adducts, which are major mutagenic lesions produced by environmental carcinogens. Polymorphisms in the AGT gene may affect the capacity to repair DNA damage and thereby have influence on individual's susceptibility to smoking-related cancer. To test this hypothesis, we investigated the potential association of AGT polymorphisms (485C > A, Leu53Leu (C > T) and Leu84Phe] with the risk of lung cancer in a Korean population. The AGT genotypes were determined in 432 lung cancer patients and in 432 healthy controls who were frequency-matched for age and gender. The 485 AA genotype was associated with a significantly increased risk for overall lung cancer as compared with the 485 CC genotype and the combined 485 CC + CA genotype, respectively (adjusted odds ratio (OR) = 1.83, 95% confidence interval (CI) = 1.12-2.99, P = 0.02, and Bonferroni corrected P-value (Pc) = 0.04; and adjusted OR = 1.67, 95% CI = 1.05-2.66, P = 0.03, respectively). When the lung cancer cases were categorized by the tumor histology, the 485 AA genotype was associated with a significantly increased risk of adenocarcinoma (AC) and small cell carcinoma (SmCC), respectively, as compared with the combined 485 CC + CA genotype (adjusted OR = 2.54, 95% CI = 1.39-4.66, P = 0.003; and adjusted OR = 2.19, 95% CI = 1.06-4.55, P = 0.04, respectively). However, the genotype distributions of the Leu53Leu and Leu84Phe polymorphisms were not significantly different between the lung cancer cases and the controls. On a promoter assay, the 485C > A polymorphism did not have an effect on the promoter activity of the AGT gene. These results suggest that the effect of the AGT 485C > A polymorphism on the risk of lung cancer may be secondary to linkage disequilibrium (LD) with either another AGT variant or with a true susceptibility gene, and that the AGT 485C > A polymorphism could be used as a marker for the genetic susceptibility to lung cancer.
    • Uptake of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by Moldovan children.

      Stepanov, Irina; Hecht, Stephen S.; Duca, Gheorghe; Mardari, Igor (2006-01)
      The evidence of an association between childhood exposure to environmental tobacco smoke (ETS) and an increased risk of lung cancer is inconsistent. However, taking into account the existing association between lung cancer and adulthood ETS exposure, it is plausible that children exposed to ETS also would be at risk of developing lung cancer later in life. In this study, we investigated the uptake by Moldovan children of the tobacco-specific lung carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) by measuring total 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), the sum of the NNK metabolites, NNAL, and its O-glucuronide and N-glucuronide (NNAL-Glucs) in urine. We also measured urinary cotinine and its glucuronide (total cotinine). Total NNAL was detected in 69 of 80 samples, including those that were low in cotinine (<5 ng/mL). The mean+/- SD level of total NNAL (0.09+/- 0.077 pmol/mL) was comparable with those observed in previous studies of children and adults exposed to ETS. Total NNAL correlated with total cotinine (r=0.8, P<0.0001). The mean+/- SD levels of total NNAL and total cotinine were higher in children who were exposed to ETS (0.1+/- 0.08 and 109+/- 126 pmol/mL, respectively) than in those who were classified as unexposed to ETS based on questionnaire data (0.049+/- 0.016 pmol/mL and 0.043+/- 0.040 nmol/mL). The results of this study for the first time show widespread and considerable uptake of nicotine and the tobacco-specific lung carcinogen NNK in Moldovan children. These results should be useful in heightening the awareness of the dangers of smoking and ETS exposure in this eastern European country.