Porcine interleukin-6 enhances the expression of CYP2C33 through a constitutive androstane receptor/retinoid X receptor-mediated pathway.

Cytochrome P450, which is expressed in humans and other animals, is a superfamily of drug-metabolizing enzymes that play important roles in the metabolism of endogenous and xenobiotic substrates via oxidation, peroxidation and reduction. Of endogenous substrates, interleukin (IL)-6 is a crucial cytokine involved in inflammation in the liver. The present study aims to elucidate the mechanisms through which IL-6 modulates cytochrome P450 expression. CYP2C33 expression was found to be increased in HepLi cells and primary porcine hepatocytes treated with IL-6 in a concentration-dependent manner. IL-6 treatment also increased the expression of the transcriptional regulators, constitutive androstane receptor (CAR) and pregnane X receptor. Overexpression of CAR promoted CYP2C33 expression at the mRNA and protein levels, whereas knockdown of CAR by small interfering RNA reduced CYP2C33 expression. Luciferase assays showed that IL-6 treatment of HepLi cells and primary porcine hepatocytes increased CYP2C33 promoter activity. Co-immunoprecipitation and western blotting demonstrated that CAR and RXR could form heterodimers. IL-6 affects CYP2C33 expression through CAR/retinoid X receptor (RXR) heterodimers.

Relationship between CYP3A29 and pregnane X receptor in landrace pigs: Pig CYP3A29 has a similar mechanism of regulation to human CYP3A4.

The objective of this study was to provide evidence of the validity of utilizing pigs as a model to study the regulation of human CYP3A4, with special emphasis on drug-drug interactions. We determined the mRNA expression and distribution of CYP3A and metabolic nuclear receptors in different tissues isolated from landrace pigs. Our results showed that CYP3A and metabolic nuclear receptor mRNAs were most highly expressed in liver tissues. The expression of the metabolic nuclear receptor pregnane X receptor (PXR) had a significant correlation with expression of CYP3A29, an analog of human CYP3A4. The correlation between their transcriptional levels was further demonstrated using LPS and TNF-α. The mRNA and protein expression of CYP3A29 and PXR in HepLi cells was significantly reduced by LPS and TNF-α treatment. CYP3A29 promoter activity was dramatically elevated by PXR over expression, whereas LPS and TNF-α treatment inhibited the enhanced CYP3A29 promoter activity that was induced by PXR; presumably through inhibition of PXR promoter activity. Furthermore, the inhibition of CYP3A29 promoter activity by LPS and TNF-α treatment was blocked by knockdown of PXR or retinoid X receptor (RXR). These data suggest high similarity in the regulation mechanism of pig CYP3A29 and human CYP3A4. Our research provided a significant evaluation to determine whether pigs are suitable as an experimental animal model.

Esophageal cancer mortality during 2004-2009 in Yanting County, China.

OBJECTIVE: Yanting County is a high risk area for esophageal cancer (EC) in China. The purpose of this study was to describe the mortality and mortality change of EC from 2004 to 2009 in Yanting County. METHODS: EC mortality data from 2004 to 2009 obtained from the Cancer Registry in Yanting were analyzed. Annual percentage changes (APC) were calculated to assess the trends in EC mortality. Age-standardized mortality was calculated based on world standard population of 2000. RESULTS: The average EC mortality was 54.7/105 in males and 31.6/105 in females over the 6 years. A decline in EC mortality with time was observed in both genders, with a rate of -8.70% per year (95% CI: -13.23%~-3.93%) in females and -4.11% per year (95%CI: -11.16%~3.50%) in males. CONCLUSION: EC mortality decreased over the six years in both genders, although it remained high in the Yanting area. There is still a need to carry out studies of risk factors for improved cancer prevention and further reduction in the disease burden.

Processed food consumption and risk of esophageal squamous cell carcinoma: A case-control study in a high risk area.

This study was conducted to investigate the association between consumption of processed foods and esophageal cancer risk. A population-based case-control study was designed. For the present study, 254 patients with esophageal squamous cell carcinoma with pathological diagnoses were selected from Yanting during 2008 and 2010 and 254 community-based controls were selected from the same area, individually matched with cases by age and sex. Data on demographic, lifestyle and dietary factors were collected using food frequency questionnaires. A conditional logistic regression model was used to estimate the odds ratio (OR) with adjustments for potential confounders. Compared to the frequency of <1 time/week, the intake frequency of >3 times/week of preserved vegetables had a significant association with esophageal cancer (OR = 5.01, 95% confidence interval [CI] 2.07, 12.17). In stratified analyses, the OR of increasing intake of preserved vegetables for esophageal cancer were 2.02 in men (95% CI 1.18, 3.48), 3.15 in women (95% CI 1.28, 7.75), 2.41 (95% CI 1.45 4.01) in the persons <65 years old and 1.28 (95% CI 0.35, 4.65) in persons ≥65 years old. Consumption of pickled vegetables was not associated significantly with esophageal cancer risk. Intake of salted meat with a frequency of ≥1 time/week meant that the OR increased to 2.57 (95%CI 1.02, 6.43), but no significant trend or association in subgroup analysis was observed. Preserved vegetable consumption was associated with increased risk of esophageal cancer, while no association was found with pickled vegetables.

[Effects of selenium and zinc on the proliferation of human esophageal cancer cell line studied by serophysiology].

OBJECTIVE: The effect of serum from rats supplemented with selenium and zinc on the proliferation of human esophageal cancer cell line Eca109 was observed by serophysiology. METHODS: Rats were randomly divided into seven groups. Eight rats in each group were fed with basic feeds (deprived of both selenium and zinc). The experimental rat groups were supplemented with selenium or zinc at low or high dosage intragastrically for 30 days Serum selenium and zinc content of rats was measured by Graphite Furnace Atomic Absorption Spectrometry (GFAAS) and Flame Atomic Absorption Spectrophotometry (FAAS). MTT assay,3H-TDR incorporation and flow cytometry were used to explore the effect of serum from different rat groups on the growth and proliferation of cancer cell line Ecal09 cells. RESULTS: (1) The content of serum zinc in the high zinc group was the highest and the content of serum zinc was the lowest in basic diet group. The content of serum selenium in high selenium and high zinc group was the highest and the content of serum selenium was the lowest in the basic diet group. (2) In comparing the growth of control cancer cell group cultured with calf serum, the growth of cancer cells cultured with the serum from high selenium and high zinc rats was inhibited in culturing for 72 h, but the growth of normal liver cells were also inhibited. The growth of cancer cells were promoted by serum from other groups. (3) Both MTT assay and 3H-TDR incorporation test showed that the DNA synthesis in cancer cells was inhibited by the serum from high selenium and high zinc group, but the DNA synthesis of normal liver cells was also inhibited by this type of serum. The result of DNA synthesis in other cell groups was closed to the control group. CONCLUSIONS: Low serum selenium and zinc might promote the growth of EC cell. Elevating the content of serum selenium and zinc by increasing selenium and zinc intake might inhibit EC cell proliferation.

Major cancer mortality and changes in Yanting, 2004-2009: introduction to cancer challenges in a high risk area.

Yanting County is one of high risk areas of esophageal cancer in China. Recently, the economic level has improved to a new standard, but cancer issues have not been updated. This study aimed to describe the main cancer mortalities and change from 2004 to 2009 and provide an evidence base for future active strategies. Yanting Cancer Research Institute provided all cancer mortality data and age-standardized rates were calculated based on the world standard population 2000. Annual percentage change was used to estimate the time trend for each cancer. Mortality from upper gastrointestinal cancers, but not other cancers, was much higher than worldwide average figures. Rates for esophageal cancer declined over the 6 years, but lung cancer mortality showed an upward trend. For gastric and liver cancer, no obvious change was observed. Considering the high mortality from upper gastrointestinal cancers, it is necessary to take actions investigating the risk factors and addressing the issues of prevalent cancer challenges.

Relationship between genetic polymorphisms of ALDH2 and ADH1B and esophageal cancer risk: a meta-analysis.

AIM: To evaluate the contribution of alcohol dehydrogenase-1B (ADH1B) and aldehyde dehydrogenase-2 (ALDH2) polymorphisms to the risk of esophageal cancer. METHODS: Nineteen articles were included by searching MEDLINE, EMBASE and the Chinese Biomedical Database, 13 on ADH1B and 18 on ALDH2. We performed a meta-analysis of case-control studies including 13 studies on ADH1B (cases/controls: 2390/7100) and 18 studies on ALDH2 (2631/6030). RESULTS: The crude odds ratio [OR (95% confidence interval)] was 2.91 (2.04-4.14) for ADH1B*1/*1 (vs ADH1B*2/*2) and 1.32 (1.17-1.49) for ADH1B*1/*2. The crude OR for ALDH2*1/*2 (vs ALDH2*1/*1) was 2.52 (1.76-3.61). ADH1B*1/*1 increased the risk of esophageal cancer among never/rare [1.56 (0.93-2.61)], moderate [2.71 (1.37-5.35)], and heavy drinkers [3.22 (2.27-4.57)]. ADH1B*1/*2 was associated with a modest risk among moderate drinkers [1.43 (1.09-1.87)]. ALDH2*1/*2 increased the risk among never/rare [1.28 (0.91-1.80)], moderate [3.12 (1.95-5.01)], and heavy [7.12 (4.67-10.86)] drinkers, and among ex-drinkers [5.64 (1.57-20.25)]. ALDH2*2/*2 increased the risk among drinkers [4.42 (1.72-11.36)]. ADH1B*1/*1 plus ALDH2*1/*2 was associated with the highest risk for heavy drinkers [12.45 (2.9-53.46)]. The results of the meta-regression analysis showed that the effects of ADH1B*1/*1 and ALDH2*1/*2 increased with the level of alcohol consumption. ALDH2*1/*2 was associated with a high risk among Taiwan Chinese and Japanese drinkers, as opposed to a moderate risk among drinkers in high-incidence regions of Mainland China. ADH1B*1/*1 in heavy drinkers and ALDH2*1/*2 in moderate-to-heavy drinkers was associated with similarly high risk among both men and women. CONCLUSION: ADH1B/ALDH2 genotypes affect the risk of esophageal cancer, and the risk is modified by alcohol consumption, ethnicity, and gender.