[Investigation of hepatitis B virus integration sites in hilar cholangiocarcinoma tissues].

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Upregulation of human telomerase reverse transcriptase mRNA expression by in vitro transfection of hepatitis B virus X gene into human hepatocarcinoma and cholangiocarcinoma cells.

AIM: To study the changes of human telomerase reverse transcriptase (hTERT) mRNA expression in human hepatocarcinoma cell lines (HepG2) and cholangiocarcinoma cell lines (QBC939) after HBx gene transfection and to illustrate the significance of transcriptional regulation of hTERT gene by HBx gene in the carcinogenesis. METHODS: HepG2 and QBC939 cell lines were cultured and co-transfected with eukaryotic expression vector containing the HBx coding region and cloning vector containing enhanced green fluorescent protein (EGFP) coding sequence using lipid-mediated gene transduction technique. Thirty-six hours after transfection, EGFP expression in cells was used as the indicator of successful transfection. Flow cytometry was performed to determine the transfection efficiency. Cells were harvested and total RNA was extracted using TRIzol reagent. The expression of hTERT mRNA in HepG2 and QBC939 cell lines was assayed by reverse transcription-polymerase chain reaction. The expression of HBx protein in both cell lines was detected by immunocytochemical staining and Western blotting. RESULTS: Flow cytometry showed that the transfection efficiency was 46.4% in HepG2 cells and 29.6% in QBC939 cells for both HBx gene expression vector and blank vector. The expression of hTERT mRNA was meaningfully increased in HepG2 and QBC939 cell lines when transfected with HBx gene expression vector compared to those transfected with OPTI-MEM medium and blank vector. Immunocytochemical staining and Western blotting revealed HBx protein expression in HepG2 and QBC939 cells only when transfected with HBx gene. CONCLUSION: HBx gene transfection can upregulate the transcriptional expression of hTERT mRNA. The transactivation of hTERT gene by HBx gene is a newfound mechanism for pathogenesis of hepatocarcinomas and cholangiocarcinomas after HBV infection.

[Isolation and purification of eccrine sweat glands in human skin].

OBJECTIVE: To investigate the method of isolation and purification of epithelial cells of human eccrine sweat gland in vitro. METHODS: Through digesting human skin with collagenase type II, cells of human eccrine sweat gland were isolated. Highly purified gland cells were obtained through transferring into the conditioned medium with a micropipette for at least three times under an inverted microscope. Primary culture was started immediately after purification. Cells could be further purified by enzyme-digestion to eradicate the fibroblasts. RESULTS: Collagenase type II could digest dermal collagen with little damage to gland cells. Isolated cells from human sweat glands were adherent to the wall of culture flask, and they grew well in cultures. The problem of contamination by tissue debris and other cells such as fibroblast could be overcome. CONCLUSION: Isolation and purification of human sweat gland cells in vitro are still facing tough problems. Gland cells are successful to isolate and cultivate without contamination.

[Culture and identification of human skin fibroblasts].

OBJECTIVE: To explore the method of isolation, cultivation, and identification of human skin fibroblasts in vitro. METHODS: By digesting human skin with collagenase type II to isolate human eccrine sweat glands. The fibroblasts grew along with the growth of eccrine sweat gland cells,and they were separated by digesting with 0.25% trypsin and 0.02% ethylenediaminetetraacetic acid (EDTA). Dulbecco's modified Eagle's medium (DMEM) was the basic culture medium, being supplemented with fetal bovine serum (10%), penicillin (100 kU/L), and streptomycin(100 mg/L) Fibroblasts were incubated at 37 centigrade in a humidified atmosphere of 5% CO2 and 95% air in the incubator. Cellular morphologies were observed by inverted phase contrast microscopy and hematoxylin-eosin staining, and the cultured cells were identified by vimentin immunostaining and chromosome analysis. RESULTS: The isolated fibroblasts could grow and proliferate in vitro, and immunostaining of vimentin was positive in cultured fibroblasts and the number of chromosome was 46. CONCLUSION: Acquired human skin fibroblasts can be cultured in stable condition in vitro, and sufficient and reliable target cells can be obtained for the study of the mechanisms of wound healing at molecular level.

[The effect of hepatitis B virus X gene transfection on expression of human telomerase reverse transcriptase mRNA in human bile duct carcinoma cell lines].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Hepatitis B virus X gene induces human telomerase reverse transcriptase mRNA expression in cultured normal human cholangiocytes.

AIM: To study the transcriptional regulation of human telomerase reverse transcriptase (hTERT) mRNA in normal human cholangiocytes (HBECs) after hepatitis B virus X (HBx) gene transfection and to elucidate the possible mechanism of HBV infection underlying cholangiocarcinoma. METHODS: HBECs were cultured in vitro and co-transfected with a eukaryotic expression vector containing the HBx coding region and a cloning vector containing coding sequences of enhanced green fluorescent protein (EGFP) using lipid-mediated gene transfer. The transfection efficiency was determined by the expression of EGFP. The expressions of hTERT mRNA and HBx protein in HBECs were detected by RT-PCR and immunocytochemical stain, respectively. RESULTS: The transfection efficiencies were about 15% for both HBx gene expression plasmid and empty vector. No hTERT mRNA was expressed in HBECs when transfected with OPTI-MEM medium and empty vector, but a dramatic increase was observed for hTERT mRNA expression in HBECs when transfected with HBx expression vector. HBx protein was only expressed in HBECs when transfected with HBx expression vector. CONCLUSION: HBx transfection can activate the transcriptional expression of hTERT mRNA. Cis-activation of hTERT mRNA by HBx gene is the primary mechanism underlying the proliferation, differentiation and tumorigenesis of biliary epithelia.

[The expression and significance of human telomerase reverse transcriptase protein and gene in bile duct carcinomas and their adjacent tissues].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[In situ nucleic acid detection of HBV X gene in extrahepatic biliary tract carcinomas and its clinicopathological significance].

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.