Investigation of hepatitis B virus integration sites in hilar cholangiocarcinoma tissues / 中华外科杂志

<p><b>OBJECTIVES</b>To study the phenomena of hepatitis B virus (HBV) integration into the tissues of hilar cholangiocarcinoma (HCCA) and to identify the integration sites in the host genome.</p><p><b>METHODS</b>Ten fresh HCCA samples were collected from the tissues by surgical ablation, 1 normal hilar bile duct sample selected as control. Cellular DNA were extracted by Wizard SV Genomic DNA Purification System. PCR-derived assay (HBV-Alu-PCR) was employed to amplify the viral-host junctions which contain the HBV sequence and the adjacent cellular flanking sequences. The PCR products were purified and subjected to sequencing by ABI-3730XL Auto DNA Analyzer. The sequence analysis of viral-host junctions was performed by DNASIS MAX 3.0 bioinformatics software. The insertion sites between viral and cellular sequences were identified through homology comparison using NCBI BLAST and MapViewer search.</p><p><b>RESULTS</b>In 10 HCCA samples, 5 were demonstrated to have HBV integration fragments with total 6 inserted sites identified. Sequence analysis from viral-host junction showed that HBV X gene inserted into host genome at random distribution with truncated fragments. HBV integration recurrently targeted the unknown region in upstream of CXXC finger protein-1 (CpG-binding protein) gene (4 cases). p53 tumor suppressor gene was also found at the integration site.</p><p><b>CONCLUSIONS</b>There is high integration rate of HBV DNA into cellular genome of HCCA. HBV integration is found frequently into or close to cancer-related genes. The findings demonstrate that HBV infection might have association with the pathogenesis of HCCA.</p>

The effect of hepatitis B virus X gene transfection on expression of human telomerase reverse transcriptase mRNA in human bile duct carcinoma cell lines / 中华外科杂志

<p><b>OBJECTIVE</b>To study the effect of Hepatitis B virus X (HBx) gene transfection on expression of human telomerase reverse transcriptase (hTERT) mRNA in human bile duct carcinoma cell lines QBC939 and to elucidate the significance of cis-activation of hTERT mRNA by HBx gene on the carcinogenesis of bile duct.</p><p><b>METHODS</b>QBC939 were cultured in vitro and co-transfected with eukaryotic expression vector containing the HBx coding region and cloning vector containing enhanced green fluorescent protein (EGFP) coding sequence using liposome-mediated gene transduction technique. Thirty six hours after transfection, EGFP expression, the indicator of successful transfection in cells, was determined. Flow cytometry was applied to determine the transfection efficiency. Cells were harvested and total RNA was extracted with TRI(ZOL) Reagent. The expression of hTERT mRNA in QBC939 was assayed by Reverse Transcription Polymerase Chain Reaction. The expression of HBx protein in QBC939 was detected by immunocytochemistry staining and western blotting.</p><p><b>RESULTS</b>The transfection efficiency was 29.6% for both HBx expression vector and vector control group. The expression of hTERT mRNA was significantly increased when transfected with HBx expression vector than that transfected with OPTI-MEM medium and vector only. The expression of HBx protein could only be found in the cells when transfected with HBx expression vector by immunocytochemistry staining and western blotting.</p><p><b>CONCLUSION</b>HBx gene transfection may up-regulate the transcriptional expression of hTERT mRNA in bile duct carcinoma cells. The cis-activation of hTERT gene by HBx gene is primary mechanism for carcinogenesis of biliary epithelia after HBV infection.</p>

The expression and significance of human telomerase reverse transcriptase protein and gene in bile duct carcinomas and their adjacent tissues / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To detect the expression of human telomerase reverse transcriptase (hTERT) protein and mRNA in bile duct carcinomas and the adjacent tissues and to elucidate its role in bile duct carcinogenesis.</p><p><b>METHODS</b>The expression of hTERT protein and hTERT mRNA in the formalin-fixed paraffin-embedded specimens of 71 cases of bile duct cancers and 39 cases of adjacent tissues was detected by streptavidin-peroxidase immunostaining and in situ hybridization. The correlation was analysed statistically between the expression of hTERT protein and mRNA and clinicopathological parameters bile duct carcinomas.</p><p><b>RESULTS</b>The positive rate of hTERT protein expression and mRNA expression in malignant specimens was 78.9% (56/71) and 67.6% (48/71), while that in the adjacent tissues was 35.9% (14/39) and 23.1% (9/39), respectively. All the positive signals were found in the hyperplastic biliary epithelia. No significant correlation was established between hTERT expression and clinicopathological parameters.</p><p><b>CONCLUSION</b>hTERT gene transcription and protein expression is most likely involved in the proliferation and malignant transformation of bile epithelia and the malignant progression of bile duct carcinomas. The detection of hTERT expression may serve elucidating the carcinogenesis of bile duct.</p>

In situ nucleic acid detection of HBV X gene in extrahepatic biliary tract carcinomas and its clinicopathological significance / 中华外科杂志

<p><b>OBJECTIVE</b>To detect the expression of HBV X gene (HBx mRNA) in extrahepatic biliary tract carcinomas and the adjacent non-cancerous tissues, and to analyzed the relationship between HBV infection and incidence of biliary tract carcinomas, thereby to elucidate the possible role of HBx in the carcinogenesis of biliary tract.</p><p><b>METHODS</b>The plasmid pSPX46 was digested by appropriate restriction enzyme. HBx fragment was obtained through gel extraction kit. The digoxigenin-labeled DNA probes for HBx mRNA were prepared by a random prime technique. The expression of HBx mRNA was detected in formalin-fixed- paraffin-embedded specimens from 71 cases of biliary tract carcinomas and 39 specimens of non-cancerous tissues adjacent to cancer by in situ hybridization. The correlations between HBx mRNA expression and clinicopathological parameters were statistically analysed in 71 cases of biliary duct carcinomas.</p><p><b>RESULTS</b>Forty-three of 71 malignant specimens had detectable HBx mRNA expression with a positive rate being 61%. Only 7 of 39 specimens of non-cancerous tissues adjacent to cancer had weak HBx mRNA expression, with a positive rate being 18%, and all these positive signals were found in the hyperplastic biliary epithelium. No significant correlation was found between HBx mRNA expression and clinicopathological parameters, but a strong positive correlation was found between HBx mRNA and protein expression.</p><p><b>CONCLUSION</b>There is a high frequency of HBx mRNA expression in extrahepatic biliary tract carcinomas. HBV infection and its gene integration might play a role to certain extent in the development of biliary tract carcinomas.</p>