Upregulation of activator protein-4 in human colorectal cancer with metastasis.

The aim of this study is to investigate the expression of AP-4, VEGF, and MMP-9 genes in human colorectal cancer. The expression pattern of activator protein-4 in 160 colorectal cancer compared with 32 colorectal adenomas and 32 normal colorectal tissues is demonstrated by tissue microarray-immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction. Apoptosis status using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling by comparing activator protein-4 positive versus activator protein-4 negative colorectal cancer is also assessed. The messenger RNA levels of vascular endothelial growth factor and matrix metalloproteinase-9 expression in activator protein-4 positive and negative colorectal cancer were measured using real-time reverse transcriptase- polymerase chain reaction. The activator protein-4 expression in normal colorectal tissue, adenoma, and adenocarcinoma were 4 of 32, 8 of 32, and 78 of 160, respectively. It is shown that the activator protein-4 expression was significantly correlated with the progression of colorectal cancer (P < .01) and differentiation and lymph node metastasis (P < .01). Our results also presented that the activator protein-4 expression was associated with the expression of matrix metalloproteinase-9 and vascular endothelial growth factor in the advanced colorectal cancer.

Decreased fragile histidine triad expression in colorectal cancer and its association with apoptosis inhibition.

AIM: To detect the expression of fragile histidine triad (FHIT) in normal colorectal tissue, colorectal adenoma and colorectal cancer (CRC) tissue, and to analyze its relationship with the clinicopathological features of CRC, and apoptosis-associated proteins (Bcl-2, Bax, survivin) and apoptosis in colorectal cancer. METHODS: FHIT mRNA analysis was performed by nested reverse transcription-polymerase chain reaction (RT-PCR) assay. Tissue microarray (TMA) was established to detect the expression of FHIT, Bcl-2, Bax and survivin genes in 80 CRC tissue specimens, 16 colorectal adenoma tissue specimens and 16 hemorrhoid (PPH) tissue specimens during the same period of time as the control. Citrate-microwave-SP was used as immunohistochemical method. The relationship between clinicopathological factors, such as differentiation grades and 5-year survival rate was observed. TUNEL assay was used to detect the apoptosis index in 80 CRC tissue specimens. RESULTS: Ten out of 26 (38.5%) CRC tissue specimens expressed aberrant FHIT transcripts, none of the aberrant FHIT transcripts was observed in the matched normal tissue and colorectal adenoma tissue by nested RT-PCR assay. The positive rate of FHIT gene expression in normal colorectal tissue, colorectal adenoma and carcinoma tissue was 93.75%, 68.75% and 46.25%, respectively. Clinicopathological analysis of patients showed that the decreased FHIT gene expression was not associated with age, sex, serum CEA levels, tumor site and size, histological classification. However, the expression of FHIT was correlated with differentiation grades, pathological stages, lymph node metastases and 5-year survival rate after operation. The positive rate of apoptosis-associated proteins (Bax, Bcl-2 and survivin) in CRC tissue was 72.50%, 51.25% and 77.50%, respectively. The expression of these apoptosis-associated proteins in CRC tissue was correlated with the expression of FHIT. The mean apoptosis index in FHIT negative tumors was significantly lower than that in FHIT positive tumors (5.41 +/- 0.23 vs 0.56 +/- 0.10, P < 0.01). CONCLUSION: The FHIT gene plays an important role in the regulation of apoptosis and decreased FHIT expression plays a key role in the initiation and progression of colorectal carcinoma.

Inhibition of aldose reductase ameliorates ethanol­induced steatosis in HepG2 cells.

Aldose reductase (AR) expression is increased in liver tissue of patients with ethanol­induced liver disease. However, the exact role of AR in the development of ethanol­induced liver disease has yet to be elucidated. The present study aimed to determine the effect of an AR inhibitor on ethanol­induced steatosis in HepG2 cells and to identify possible underlying molecular mechanisms. Steatosis was induced in HepG2 cells by stimulating cells with 100 mM absolute ethanol for 48 h. Oil Red O staining was used to detect the lipid droplet accumulation in cells. Western blot analyses were used to determine protein expression levels and reverse transcription­quantitative polymerase chain reaction was used to analyze mRNA expression levels. The results showed that AR protein expression was elevated in HepG2 cells stimulated with ethanol. HepG2 cells exhibited marked improvement of ethanol­induced lipid accumulation following treatment with the AR inhibitor zopolrestat. Phosphorylation levels of 5' adenosine monophosphate­activated protein kinase (AMPK) were markedly higher, whereas the mRNA expression levels of sterol­regulatory element­binding protein (SREBP)­1c and fatty acid synthase (FAS) were significantly lower in zopolrestat­treated and ethanol­stimulated HepG2 cells compared with in untreated ethanol­stimulated HepG2 cells. In addition, zopolrestat inhibited the ethanol­induced expression of tumor necrosis factor (TNF)­α. These results suggested that zopolrestat attenuated ethanol­induced steatosis by activating AMPK and subsequently inhibiting the expression of SREBP­1c and FAS, and by suppressing the expression of TNF­α in HepG2 cells.

Down-regulation of FHIT inhibits apoptosis of colorectal cancer: mechanism and clinical implication.

Fragile histidine triad (FHIT) gene, a candidate tumor suppressor gene located at 3p14.2, has been shown to be involved in carcinogenesis of many human tissues, including digestive tract tissues. However, the expression and role of FHIT in the initiation and the development of the colorectal cancer (CRC) are poorly understood. In our present study, we have demonstrated that the FHIT gene exhibits significantly decreased expression in human CRC compared to colorectal adenoma and normal colorectal tissue by tissue microarray (TMA). The positive of FHIT gene expression in normal colorectal tissue, adenoma and adenocarcinoma were 93.75%, 68.75% and 46.25%, respectively. We showed that decreased FHIT expression was significantly correlated with the progression of colorectal carcinoma (P<0.05) as well as differentiation and lymph node metastasis (P<0.05). Two somatic mutations in the FHIT gene were also detected in human CRC. The presence of these mutations correlated significantly with decreased FHIT expression in the human CRC. In addition, we identified decreased FHIT expression resulting in apoptosis inhibition and decreasing apoptosis associated with abnormal levels of some pro- and anti-apoptotic proteins (Bax, Bcl-2 and Survivin) by TUNEL and TMA. Our results demonstrated that the mutation in the FHIT gene significantly reduced FHIT expression in human CRC. Both TUNEL and TMA experiments demonstrated significantly inhibited apoptosis by down-regulation of Bax and up-regulation of Survivin and Bcl-2. Collectively, these studies identify the mechanism by which an important tumor suppressor gene, FHIT, inactivated specifically in human CRC, and contributes to our understanding of the mechanism of colorectal carcinogenesis.

Levels, distributions and correlations of polybrominated diphenyl ethers in air and dust of household and workplace in Shanghai, China: implication for daily human exposure.

Polybrominated diphenyl ethers (PBDEs) were measured in air (TSP and PM2.5) and dust samples collected from 16 households and the corresponding workplaces of eight volunteer citizens in Shanghai, China. The PBDEs concentrations in the workplace air (mean: 281 ± 126 pg m(-3)) were over two times higher than those in the household (121 ± 44.0 pg m(-3)), while the mean levels of PBDEs in dust were 995 ± 547 and 544 ± 188 ng g(-1) for workplace and household, respectively. BDE209 was the most abundant congener in all samples. PBDEs appeared to be composed of mostly small particles. The C particle/C dust ratios of less brominated PBDEs in PM2.5 were higher than those in TSP, while the values were approximately constant for the more brominated PBDEs. A correlation analysis by network indicated different sources and behavior of the PBDE congeners. The results of a cluster analysis were displayed on a heat map that specified the source and abundance of each PBDE congener. The daily PBDE exposure via dust ingestion was the predominant part of the total intake and was more than 10 times higher than the intake via inhalation.

Brominated flame retardants in the hair and serum samples from an e-waste recycling area in southeastern China: the possibility of using hair for biomonitoring.

Hair samples and paired serum samples were collected from e-waste and urban areas in Wenling of Zhejiang Province, China. The PBDE and DBDPE concentrations in hair and serum samples from e-waste workers were significantly higher than those of non-occupational residents and urban residents. BDE209 was the dominating BFRs in hair and serum samples from the e-waste area, while DBDPE was the major BFRs from the urban area. Statistically significant correlations were observed between hair level and serum level for some substances (BDE209, DBDPE, BDE99, BDE47, BDE28, and BDE17), although the PBDE congener profiles in hair were different from those in the serum. A statistically significant positive correlation between the PBDE concentrations and the working age, as well as gender difference, was observed in e-waste workers. Different sources of PBDEs and DBDPE in three groups were identified by principal component analysis and spearman correlation coefficient. Hair is suggested to be a useful matrix for biomonitoring the PBDE exposure in humans.

Polybrominated diphenyl ethers in resident Eurasian Tree Sparrow from Shanghai: geographical distribution and implication for potential sources.

An investigation of polybrominated diphenyl ethers (PBDEs) in Eurasian Tree Sparrow (Passer montanus) samples (n=37) collected from different land use areas in Shanghai provided information about the levels, compositional patterns, geographical distribution, potential sources of PBDEs and the evaluation of contamination status in Shanghai. The concentrations of BDE 209 and Sum-PBDEs were within the range of 8.20-292.0 ng g(-1) lw (median: 47.0 ng g(-1) lw) and 33.16-375.63 ng g(-1) lw (median: 78.7 ng g(-1) lw), respectively. As the predominant individual congener, BDE 209 was detected in all samples with a mean percentage of 62.8%, followed by BDE 47, 99 and 100 sequentially. The geographical distribution of PBDEs in ETS muscles followed the order below: landfill>urban>industrial parks>suburban>rural>remote, indicating that Shanghai Laogang Municipal Landfill was an important emission source of PBDEs in Shanghai, and also the PBDE levels were in association with urbanization and industrialization. Compared with other regions, contamination status in Shanghai was relatively good with the exception of these high concentration areas. There was significant correlation (r(2)=0.89, P<0.01) between PBDEs concentrations in soil and ETS, indicating ETS could be used as a useful biomonitoring tool for PBDEs in Shanghai.

Absence of FHIT expression is associated with apoptosis inhibition in colorectal cancer.

The fragile histidine triad (FHIT) gene, a candidate tumor suppressor gene located at 3p14.2, has been shown to be involved in the carcinogenesis of many human tissues, including digestive tract tissues. However, the expression and the role of the FHIT in the initiation and the development of the colorectal cancer (CRC) are poorly understood. We have shown that the FHIT gene exhibits significantly decreased expression in human CRC compared to colorectal adenoma and normal colorectal tissue by tissue microarray (TMA). The positive rate of FHIT gene expression in normal colorectal tissue, adenoma and adenocarcinoma were 93.75%, 68.75% and 46.25%, respectively. We show this decreased expression to be significantly correlated with the progression of colorectal carcinoma (P<0.05) as well as with differentiation and lymph node metastasis (P<0.05). We detected two somatic alterations in the FHIT gene in human CRC. The presence of this mutation correlated significantly with decreased FHIT expression in the human CRC. In our present study we tested the hypothesis that the decreased FHIT expression resulted in apoptosis inhibition associated with abnormal expression of apoptosis related proteins. To test this hypothesis we did a series of experiments. In the first test, we assessed apoptosis status using a standard TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling) assay by comparing FHIT-positive CRC vs. FHIT-negative CRC. In the second experiment, the protein expression of the FHIT and other apoptosis related proteins (Bax, Bcl-2 and Survivin) were measured in human CRC by TMA. Our combined results demonstrate the mutation in the FHIT gene significantly reduced FHIT expression in human CRC. Both TUNEL and TMA experiments demonstrated significantly inhibited apoptosis by down-regulation of Bax and the up-regulation of Survivin and Bcl-2. Collectively, these studies identify the mechanism by which an important tumor suppressor gene, FHIT is inactivated specifically in human CRC contributing to our understanding of the mechanism of colorectal carcinogenesis.