Normal Biliary Epithelial Cells Research Articles

Magnetic resonance imaging features of choledochal traumatic neuroma

Objective To summarize magnetic the resonance imaging (MRI) features of choledochal traumatic neuroma, and investigate the key points of diagnosis and differentiation. Methods This was a retrospective descriptive study. The clinicopathological data of 1 patient with choledochal traumatic neuroma who was admitted to the Yantaishan Hospital on 18 August, 2015 were collected. The patient received pre-contrast and dynamic-contrast-enhanced MRI and MR cholangiopancreatography (MRCP). Observational indexes included: (1) imaging features: location, size, signal intensity and enhancement characteristics of the lesion; (2) treatment and prognosis: surgical treatment, pathological findings, results of immunohistochemical staining and clinical follow-up. After preoperative related examinations, the patient and relatives were willing to receive surgical therapy, and postoperative pathological examinations and immunohistochemical staining were conducted. The follow-up using outpatient examination was performed to detect the patient′s recovery and clinical symptoms up to January 2016. Ultrasound and laboratory examinations [alanine transaminase (ALT), aspartate transaminase (AST), γ-glutamyl transpeptidase (GGT) and total bilirubin (TBil)] were also recorded. Results (1) Imaging features: pre-contrast MRI revealed a stricture and intra-lumen nodular in the middle portion of common bile duct. The nodular was measured 1.2 cm×0.9 cm at maximum cross-section. The nodular was well-demarcated and homogeneous of hypointensity on T1-weighted image comparing to hepatic parenchyma, slight hyperintensity on T2-weighted image and slight hypointensity on fat-suppressed T2-weighted image. MRCP could demonstrate the nodular more clearly and dilation of distal bile duct and intra-hepatic bile ducts. The width of common bile duct was 1.4 cm. After administration of contrast materials, the nodular showed avid enhancement and delay enhancement, which was mild enhancement at the artery phase, and gradual increase at the portal vein phase and the delay phase. The length of central stricture of the common bile duct was 1.3 cm. There was no abnormal enhancement in liver, spleen and pancreas. No retroperitoneal lymphadenopathy could be seen. The imaging diagnosis was cholangiocarcinoma with dilation of bile ducts. (2) Treatment and prognosis: the patient received surgery for tumor resection and Roux-en-Y reconstruction. The removed gross specimen was a grey-white nodular measured 2.0 cm×1.0 cm. The cute surface was grey-white and stiff. The microscopic evaluation revealed haphazard arrangement of nerve bundles within the hyperplasia fibrotic stroma. Normal biliary epithelial cells can be seen beside the nerve bundles. Immunohistochemical staining showed S-100 and Vimentin were positive. The index of Ki-67 was 5%. The patient was discharged at 14 days postoperatively with the good recovery. During postoperative 5-month follow-up, the patient had good recovery and jaundice scleras were disappeared. Ultrasound showed the bile ducts were not dilated. The results of laboratory examinations were normal. Conclusion MRI features of choledochal traumatic neuroma include an intra-lumen nodular with biliary stricture and avid and delay enhancement after contrast materials administration. Key words: Traumatic neuroma; Biliary system; Magnetic resonance imaging

MicroRNA-101 inhibits the migration and invasion of intrahepatic cholangiocarcinoma cells via direct suppression of vascular endothelial growth factor-C.

MicroRNAs (miRs) have important roles in the pathogenesis of human malignancy. It has previously been suggested that deregulation of miR‑101 is associated with the progression of intrahepatic cholangiocarcinoma (ICC); however, the exact role of miR‑101 in the regulation of ICC metastasis remains largely unknown. The present study demonstrated that the expression levels of miR‑101 were significantly decreased in ICC tissue, as compared with matched adjacent normal tissue. Furthermore, miR‑101 was downregulated in the ICC‑9810 human ICC cell line, as compared with in the normal human intrahepatic biliary epithelial cell (HIBEC) line. Vascular endothelial growth factor (VEGF)‑C was identified as a target gene of miR‑101 in ICC‑9810 cells. The expression of VEGF‑C was negatively regulated by miR‑101 at the post‑transcriptional level in ICC‑9810 cells. Further investigation demonstrated that overexpression of miR‑101 markedly suppressed the migration and invasion of ICC‑9810 cells, and these effects were similar to those observed following VEGF‑C knockdown. Conversely, restoration of VEGF‑C reversed the inhibitory effects of miR‑101 overexpression on ICC‑9810 cell migration and invasion, thus suggesting that miR‑101 may suppress ICC‑9810 cell migration and invasion, at least partly via inhibition of VEGF‑C. It was also demonstrated that the mRNA and protein expression levels of VEGF‑C were frequently upregulated in ICC tissue and cells, and its expression level was inversely correlated with that of miR‑101 in ICC tissue. In conclusion, the present study identified important roles for miR‑101 and VEGF‑C in ICC, suggesting that miR‑101/VEGF‑C signaling may be a promising diagnostic and/or therapeutic target for ICC.

MiR-376c Down-Regulation Accelerates EGF-Dependent Migration by Targeting GRB2 in the HuCCT1 Human Intrahepatic Cholangiocarcinoma Cell Line

MicroRNA miR-376c was expressed in normal intrahepatic biliary epithelial cells (HIBEpiC), but was significantly suppressed in the HuCCT1 intrahepatic cholangiocarcinoma (ICC) cell line. The biological significance of the down-regulation of miR-376c in HuCCT1 cells is unknown. We hypothesized that miR-376c could function as a tumor suppressor in these cells. To test this hypothesis, we sought the targets of miR-376c, and characterized the effect of its down-regulation on HuCCT1 cells. We performed proteomic analysis of miR-376c-overexpressing HuCCT1 cells to identify candidate targets of miR-376c, and validated these targets by 3′-UTR reporter assay. Transwell migration assays were performed to study the migratory response of HuCCT1 cells to miR-376c overexpression. Furthermore, microarrays were used to identify the signaling that were potentially involved in the miR-376c-modulated migration of HuCCT1. Finally, we assessed epigenetic changes within the potential promoter region of the miR-376c gene in these cells. Proteomic analysis and subsequent validation assays showed that growth factor receptor-bound protein 2 (GRB2) was a direct target of miR-376c. The transwell migration assay revealed that miR-376c significantly reduced epidermal growth factor (EGF)-dependent cell migration in HuCCT1 cells. DNA microarray and subsequent pathway analysis showed that interleukin 1 beta and matrix metallopeptidase 9 were possible participants in EGF-dependent migration of HuCCT1 cells. Bisulfite sequencing showed higher methylation levels of CpG sites upstream of the miR-376c gene in HuCCT1 relative to HIBEpiC cells. Combined treatment with the DNA-demethylating agent 5-aza-2′-deoxycytidine and the histone deacetylase inhibitor trichostatin A significantly upregulated the expression of miR-376c in HuCCT1 cells. We revealed that epigenetic repression of miR-376c accelerated EGF-dependent cell migration through its target GRB2 in HuCCT1 cells. These findings suggest that miR-376c functions as a tumor suppressor. Since metastasis is the major cause of death in ICC, microRNA manipulation could lead to the development of novel anti-cancer therapy strategies for ICC.

Transcribed ultraconserved regions are aberrantly expressed and can be modulated by interleukin 6 in cholangiocarcinoma

BackgroundThe inflammation-associated cytokine interleukin (IL) 6 has been implicated in cholangiocarcinogenesis. Transcripts encoded by a group of highly conserved regions (transcribed-ultraconserved regions [T-UCRs]) are novel promising non-coding RNAs that proved to have a role in human carcinogenesis and liver cancer progression. We aimed to study expression of T-UCRs in cholangiocarcinoma. MethodsMzChA-1, TFK, CC-LP-1, and KMCH human cholangiocarcinoma cells, and normal human intrahepatic biliary epithelial cells (HIBEC) were used. T-UCR expression profiling was done with real-time PCR. IL-6 dependent T-UCR expression was assessed in Mz-ChA-1 cells incubated with 10 ng/L IL6 for 24 h or stably transfected with full-length IL6 (Mz-IL6). FindingsThe expression of 65 T-UCRs was altered in Mz-ChA-1 compared with normal HIBEC cells. Of these, 12 T-UCRs were upregulated by more than two fold and 48 T-UCRs were downregulated including ultraconserved RNA uc.169, which was dramatically reduced in other human cholangiocarcinoma cell lines and tissues. uc.169 was further reduced in Mz-ChA-1 cells overexpressing IL6. Incubation of MzChA-1 cells with IL6 reduced expression of uc.169, and pretreatment with the inhibitor of transcription actinomycin D inhibited this effect. Enforced expression of IL6 caused an increase in the microRNAs miR-21 and miR-26-a1, which are involved in promotion of cholangiocarcinoma. The uc.169 sequence includes target seed regions for miR-21 and miR-26-a1 and they may be responsible for the downregulation of uc.169. Overexpression of uc.169 in Mz-ChA-1 cells reduced cell proliferation and caused arrest in phase G0/1 of the cell cycle, with increased apoptosis. InterpretationWe report that T-UCRs are differentially expressed in malignant human cholangiocytes, and that IL6 can modulate the expression of selected T-UCRs, probably through a miRNA-mediated modulation. These studies highlight for the first time a role of ultraconserved non-coding RNAs as novel effectors of IL-6 signalling, and the involvement of these RNA genes in the pathogenesis of cholangiocarcinoma. They lay the bases to further investigation of the clinical implications of T-UCR in human cholangiocarcinoma. FundingUniversity of Glasgow.

Genetic and epigenetic alterations are involved in the regulation of TPM1 in cholangiocarcinoma

Cholangiocarcinoma is a malignant tumor originating from biliary epithelial cells. The tumor suppressor gene tropomyosin 1 (TPM1) is downregulated in several human cancer types; however, its expression status in cholangiocarcinoma is still unknown. We elucidated TPM1 expression and its regulation mechanism in cholangiocarcinoma. Real-time (RT)-PCR, western blot analysis and immunohistochemistry were performed to examine TPM1 expression levels in cholangiocarcinoma cell lines and tumor tissues. Cell lines were treated with lentiviral vector containing the miR-21 knockdown and inhibitors of genetic and epigenetic mechanisms (manumycin A, LY294002, U0126, DAC and TSA), and the TPM1 expression change was observed by RT-PCR and western blot analyses. Cell proliferation, apoptosis and migration were evaluated by water-soluble tetrazolium salt (WST-1) assay, flow cytometry and wound healing experiments, respectively. TPM1 was downregulated in the intrahepatic cholangiocarcinoma cells (HuCCT1) and upregulated in the extrahepatic cholangiocarcinoma cells (QBC939) compared with normal intrahepatic biliary epithelial cells (HIBEC). TPM1 stained negative in the intrahepatic cholangiocarcinoma tissues, as revealed by immunohistochemistry, although there was no significant difference in staining of the intrahepatic cholangiocarcinoma tissues and adjacent non-cancer tissues. RAS and two important downstream signaling pathways (RAS/PI3K/AKT and RAS/MEK/ERK) were involved in TPM1 regulation and inhibition of the epigenetic mechanisms such as DNA methylation, histone deacetylation and miR-21 upregulation upregulated TPM1 expression. Inhibitors of genetic and epigenetic mechanisms (manumycin A, LY294002, U0126, DAC and TSA) inhibited cell proliferation and migration and induced apoptosis. These data indicated that TPM1 is downregulated in HuCCT1 cells and that the Ras signaling pathway as well as DNA methylation, histone deacetylation and miR-21 upregulation play important roles in the suppression of TPM1 expression in HuCCT1 cells. Thus, compounds that inhibit genetic and epigenetic mechanisms may be promising agents in treating cholangiocarcinoma.

Loss of EBP50 stimulates EGFR activity to induce EMT phenotypic features in biliary cancer cells

Scaffold proteins form multiprotein complexes that are central to the regulation of intracellular signaling. The scaffold protein ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) is highly expressed at the plasma membrane of normal biliary epithelial cells and binds epidermal growth factor receptor (EGFR), a tyrosine kinase receptor with oncogenic properties. This study investigated EBP50-EGFR interplay in biliary cancer. We report that in a collection of 106 cholangiocarcinomas, EBP50 was delocalized to the cytoplasm of tumor cells in 66% of the cases. Ectopic expression of EBP50 was correlated with the presence of satellite nodules and with the expression of EGFR, which was at the plasma membrane, implying a loss of interaction with EBP50 in these cases. In vitro, loss of interaction between EBP50 and EGFR was mimicked by EBP50 depletion using a small interfering RNA approach in human biliary carcinoma cells co-expressing the two proteins at their plasma membrane, and in which interaction between EBP50 and EGFR was validated. EBP50 depletion caused an increase in EGFR expression at their surface, and a sustained activation of the receptor and of its downstream effectors (extracellular signal-regulated kinase 1/2, signal transducer and activator of transcription 3) in both basal and EGF-stimulated conditions. Cells lacking EBP50 showed epithelial-to-mesenchymal transition-associated features, including reduction in E-cadherin and cytokeratin-19 expression, induction of S100A4 and of the E-cadherin transcriptional repressor, Slug, and loss of cell polarity. Accordingly, depletion of EBP50 induced the disruption of adherens junctional complexes, the development of lamellipodia structures and the subsequent acquisition of motility properties. All these phenotypic changes were prevented upon inhibition of EGFR tyrosine kinase by gefitinib. These findings indicate that loss of EBP50 at the plasma membrane in tumor cells may contribute to biliary carcinogenesis through EGFR activation.

Genome-wide expression patterns associated with oncogenesis and sarcomatous transdifferentation of cholangiocarcinoma

BackgroundThe molecular mechanisms of CC (cholangiocarcinoma) oncogenesis and progression are poorly understood. This study aimed to determine the genome-wide expression of genes related to CC oncogenesis and sarcomatous transdifferentiation.MethodsGenes that were differentially expressed between CC cell lines or tissues and cultured normal biliary epithelial (NBE) cells were identified using DNA microarray technology. Expressions were validated in human CC tissues and cells.ResultsUsing unsupervised hierarchical clustering analysis of the cell line and tissue samples, we identified a set of 342 commonly regulated (>2-fold change) genes. Of these, 53, including tumor-related genes, were upregulated, and 289, including tumor suppressor genes, were downregulated (<0.5 fold change). Expression of SPP1, EFNB2, E2F2, IRX3, PTTG1, PPARγ, KRT17, UCHL1, IGFBP7 and SPARC proteins was immunohistochemically verified in human and hamster CC tissues. Additional unsupervised hierarchical clustering analysis of sarcomatoid CC cells compared to three adenocarcinomatous CC cell lines revealed 292 differentially upregulated genes (>4-fold change), and 267 differentially downregulated genes (<0.25 fold change). The expression of 12 proteins was validated in the CC cell lines by immunoblot analysis and immunohistochemical staining. Of the proteins analyzed, we found upregulation of the expression of the epithelial-mesenchymal transition (EMT)-related proteins VIM and TWIST1, and restoration of the methylation-silenced proteins LDHB, BNIP3, UCHL1, and NPTX2 during sarcomatoid transdifferentiation of CC.ConclusionThe deregulation of oncogenes, tumor suppressor genes, and methylation-related genes may be useful in identifying molecular targets for CC diagnosis and prognosis.

The evidence supports a viral aetiology for primary biliary cirrhosis

Several lines of evidence implicate an infectious process in patients with primary biliary cirrhosis (PBC). For example, the disease clusters in specific geographic areas and children emigrating from a low incidence area develop the relative incidence of their new home [1]. Also, unrelated members in the same household, such as spouses and care providers, have been reported to develop PBC. The disease reoccurs following liver transplantation, and more potent regimens using tacrolimus have resulted in earlier and more severe recurrence. In contrast, cyclosporine protects against the development of recurrent PBC, which is interesting because it is a weaker immunosuppressant that has antiviral activity against several viral agents, including betaretroviruses [2]. In co-cultivation studies, there are data showing that a transmissible agent from PBC patients’ lymph nodes can trigger a PBC specific phenotype with aberrant expression of mitochondrial proteins on the surface of normal biliary epithelial cells in vitro [3]. A few clues emerged to suggest that a virus might be implicated in PBC. With the help of Bob Garry, my laboratory found evidence of antibody reactivity to retroviruses in PBC serum [4] and James Neuberger’s laboratory found electron microscopy evidence of viral particles in PBC biliary epithelial cells (BEC) in collaboration with Bill Carmen [5]. We then used a PCR method capable of amplifying any retrovirus reverse transcriptase gene and cloned a human betaretrovirus (HBRV) sequence with 95% nucleotide homology to the mouse mammary tumor virus (MMTV) from a PBC biliary epithelium cDNA library [5]. We found that HBRV was detected in 75% PBC patient’s lymph nodes by RT-PCR and immunochemistry. However, the virus was difficult to detect in liver samples and was only observed in 30% of PBC samples by RT-PCR [5]. Indeed, the low viral burden has led to considerable controversy, as others have been unable to link HBRV with PBC. Specifically, Selmi and colleagues found no proviral DNA sequences in any patients’ livers [6] and Johal found that a low frequency of patients without PBC bore proviral DNA sequences [7], which is to be expected as there is general agreement that both genetic susceptibility and an environmental factor are required to trigger disease [1]. On close inspection all these PCR studies are concordant but interpretation varies considerably depending on the author. As

Claudin-7 protein differentiates canine cholangiocarcinoma from hepatocellular carcinoma.

The aim of the present study was to characterise the expression pattern of claudin-7 tight junction protein in canine normal liver, hyperplastic and primary neoplastic lesions of the canine liver and whether this tight junction protein can help differentiate canine cholangiocarcinomas from canine hepatocellular carcinomas. Necropsy samples included 15 canine normal liver tissue samples, 10 hepatocellular nodular hyperplasias, 6 hepatocellular adenomas, 15 well-differentiated and 6 poorly differentiated hepatocellular carcinomas, 6 cholangiocellular hyperplasias, 10 cholangiocellular adenomas, 15 well-differentiated and 6 poorly differentiated cholangiocarcinomas, 6 normal extrahepatic bile ducts, 8 normal gall bladder tissue samples, and 5 cystic mucinous hyperplasias of the gall bladder. In all canine normal liver tissue samples the hepatocytes were negative for claudin-7 and the normal biliary epithelial cells showed intense basolateral membrane claudin-7 positivity. In all cholangiocellular hyperplasia samples and in all cholangiocellular adenoma samples the benign cholangiocytes showed intense basolateral membrane positivity for claudin-7. In all samples of the well-differentiated and poorly differentiated cholangiocarcinomas, the malignant neoplastic biliary epithelial cells showed intense basolateral membrane positivity for claudin-7. Neither the hyperplastic nodules of the liver cells nor the hepatocellular adenomas reacted with claudin-7. The well-differentiated and poorly differentiated hepatocellular cancers were negative for claudin-7. The epithelial cells of canine normal extrahepatic bile ducts, gall bladder and cystic mucinous hyperplasias of the gall bladder showed intense basolateral membrane positivity for claudin-7. Differences in the intensity of claudin-7 reaction were not apparent among different types of proliferative lesions of cholangiocytes or degrees of cellular differentiation of neoplastic biliary epithelial cells. Consequently, we hypothesize that claudin-7 is an excellent immunohistochemical marker of the cholangiocellular differentiation in canines and can be used to detect benign and malignant proliferative lesions of the canine biliary tract. It can also help to differentiate canine cholangiocarcinomas from hepatocellular carcinomas.

Hepatitis C virus core protein induces malignant transformation of biliary epithelial cells by activating nuclear factor‐κB pathway

In an earlier study, we found that hepatitis C virus core protein, HCV-C, participated in the malignant transformation of HCV-C transfected normal human biliary epithelial (hBE) cells by activating telomerase. Here we further investigated the signaling of the malignant transformation. Reverse transcription-polymerase chain reaction (RT-PCR), western blotting and immunoprecipitation were used to analyze the expression of HCV-C, human telomerase reverse transcriptase (hTERT), nuclear factor-kappaB (NF-kappaB) and NF-kappaB inhibitor alpha (IkappaBalpha) genes and the phosphorylation level of IkappaBalpha protein. Electrophoretic mobility shift assays (EMSA) and NF-kappaB-linked luciferase reporter assays were carried out to measure NF-kappaB activity. The expression of HCV-C and hTERT was detected only in HCV-C-transfected hBE (hBE-HCV-C) cells but not in vector-transfected or parental hBE cells. More NF-kappaB protein accumulated in nuclear extracts of hBE-HCV-C cells rather than in those of control cells, though total NF-kappaB protein level showed no difference among these cells. DNA binding activity of NF-kappaB and the NF-kappaB-linked luciferase activity were much higher in HCV-C-transfected hBE cells than those in vector- or non-transfected hBE cells. In addition, the IkappaBalpha phosphorylation level, but not the IkappaBalpha mRNA or protein levels, was increased after HCV-C transfection. Hepatitis C virus core protein activates NF-kappaB pathway in hBE cells by increasing the phosphorylation of IkappaBalpha. The pathway may be responsible for HCV-C-induced malignant transformation of hBE cells.

Hypoxia/reoxygenation up-regulates death receptor expression and enhances apoptosis in human biliary epithelial cells

Aims To investigate whether ischemia/reperfusion (I/R)-induced apoptosis in the bile duct epithelium could be mediated by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptors in biliary epithelial cells, we examined the effects of hypoxia/reoxygenation (H/R) on TRAIL cytotoxicity. Main methods Using an H/R model, normal primary human intrahepatic biliary epithelial cells were exposed to hypoxia for 1 h, and then reoxygenated. Expressions of death receptor 4 (DR4) and DR5 mRNA and protein were measured. After 1 h of hypoxia, biliary epithelial cells were treated with TRAIL in different concentrations for 4 h. The death of biliary epithelial cells was confirmed by analysis of apoptosis and methylthiazolyl tetrazolium. The activities of caspase-3 and caspase-8 were determined by fluorometric assay. Key findings Compared with normoxic-cultured cells, the mRNA expressions of DR4 and DR5 were up-regulated from 0 min after reoxygenation, reaching a peak value at 60 min after reoxygenation. The protein expression of DR4 was most intense at 90 min after reoxygenation; the most intense expression of DR5 came at 120 min after reoxygenation. The apoptosis rate increased in the TRAIL treatment group and further increased in the TRAIL plus H/R group, and the effect of concentration-dependent TRAIL-mediated cell killing was more pronounced. Caspase-3 and caspase-8 enzymatic activities after H/R also increased with increased TRAIL concentration. Significance H/R up-regulated the expression of DR4 and DR5, and enhanced TRAIL-mediated apoptosis in normal human intrahepatic biliary epithelial cells.

MicroRNA-98 and let-7 Confer Cholangiocyte Expression of Cytokine-Inducible Src Homology 2-Containing Protein in Response to Microbial Challenge

Posttranscriptional gene regulation by microRNAs (miRNAs) has been implicated in the fine-tuning of TLR-mediated inflammatory response. The cytokine-inducible Src homology 2-containing protein (CIS), one member of the suppressors of cytokine signaling family of proteins, is an important negative regulator for inflammatory cytokine signaling. Using in vitro models using normal human biliary epithelial cells (cholangiocytes), we demonstrated that LPS stimulation or infection with the parasitic protozoan Cryptosporidium parvum induced expression of CIS protein without a change in CIS mRNA levels by activating the TLR signaling pathway. Of those miRNAs expressed in cholangiocytes, we found that targeting of the 3'-untranslated region of CIS by microRNA-98 (miR-98) or let-7 resulted in translational repression, but not CIS mRNA degradation. LPS stimulation or C. parvum infection decreased cholangiocyte expression of miR-98 and let-7. Down-regulation of miR-98 and let-7 relieved miRNA-mediated translational suppression of CIS and contributed to LPS- and C. parvum-stimulated CIS protein expression. Moreover, gain-of-function (by overexpression of CIS) and loss-of-function (by siRNA interference) studies revealed that CIS could enhance IkappaBalpha degradation and regulate NF-kappaB activation in cholangiocytes in response to LPS stimulation or C. parvum infection. Our data suggest that miR-98 and let-7 confer cholangiocyte expression of CIS in response to microbial challenge, a process that may be relevant to the regulation of TLR-mediated epithelial innate immune response.

Lipopolysaccharide Initiates a Positive Feedback of Epidermal Growth Factor Receptor Signaling by Prostaglandin E2 in Human Biliary Carcinoma Cells

Bacterial products (e.g., LPS) are viewed as critical stimuli in inflammation-associated cancer. Cyclooxygenase 2 (COX-2), a major effector of LPS, and EGFR, are key to carcinogenesis, notably in the hepatobiliary tract. In this study, we tested the hypothesis that LPS can initiate an interaction between the epidermal growth factor receptor (EGFR) and COX-2 pathways. We examined the effect of LPS in biliary carcinoma cells that displayed constitutive COX-2 expression and PGE(2) production and in normal human biliary epithelial cells in which COX-2/PGE(2) expression was virtually absent. LPS induced early phosphorylation of EGFR and ERK1/2 in both types of cells, which reached maximum levels within 30 min (first phase). However, only the carcinoma cells showed a second significant rise in both EGFR and ERK phosphorylation 6 h after exposure to LPS (second phase). Inhibition of COX-2/PGE(2) production prevented the second, but not the first, phase of EGFR and ERK1/2 phosphorylation, implicating COX-2/PGE(2) in the second phase of phosphorylation. LPS induced COX-2-derived PGE2 production at 4 h, which was before the rise in the second phosphorylation that occurred at 6 h. Exogenous PGE(2) also caused EGFR activation via a signaling pathway involving TACE-dependent TGF-alpha release. Inhibition of the second phase of EGFR phosphorylation with EGFR or COX-2 inhibitor prevented LPS-induced cell invasion in vitro, demonstrating the biological importance of this COX-2 feedback signaling in cancer cells. We conclude that LPS triggers a positive feedback loop involving COX-2/PGE(2) in biliary carcinoma cells and that this second phase of EGFR phosphorylation is implicated in cell invasion by LPS.

MicroRNA Profiling of Human Intrahepatic Cholangiocarcinoma Cell Lines Reveals Biliary Epithelial Cell-specific MicroRNAs

Intrahepatic cholangiocarcinoma (ICC), which arises in the small bile ducts of the liver, is the second most common liver malignancy. Although modulation of microRNA (miRNA) expression has been shown to be a potent sign of malignant tumors, miRNA profiles of ICC remains unclear. We performed sequencing analysis of the small RNA libraries of 2 ICC cell lines (HuCCT1 and MEC) and one normal intrahepatic biliary epithelial cell line (HIBEpiC) to produce the miRNA profiles of ICC in vitro. Furthermore, by means of the real-time polymerase chain reaction (PCR) we validated the differential expression of miRNAs cloned exclusively or predominantly from each of the cell lines. A total of 35,759 small RNA clones were obtained from the 3 cell lines. We identified 27 miRNAs that were expressed exclusively or predominantly in each cell line. Subsequent validation with the real-time PCR confirmed that the miRNAs hsa-miR-22, -125a, -127, -199a, -199a*, -214, -376a, and -424 were expressed specifically in HIBEpiC but were downregulated in the ICC cell lines. Our study provides important information for facilitating studies of the functional role(s) of miRNAs in carcinogenesis of the hepatobiliary system. The biliary epithelial cell-specific miRNAs identified in this study may serve as potential biomarkers for ICC.

CD56 as a useful marker in the regenerative process of the histological progression of primary biliary cirrhosis

Owing to recent contradicting results in the study of the regenerative process after hepatic injury in primary biliary cirrhosis, we investigated the use of CD56 in tissue repair during the histological progression of primary biliary cirrhosis. Fifty-three specimens were classified into Ludwig's stages (1-4) as follows: 14 specimens as stage 1, 23 as stage 2, 14 as stage 3, and two as stage 4. Immunohistochemical stain was performed for CD56. The cell types expressing the marker were morphologically analyzed to determine their origin. In normal liver biliary epithelial cells (including the epithelium of terminal bile ducts and bile ductules), hepatocytes, and intermediate cells (features between hepatocytes and biliary cells, distributed in interface between hepatic parenchyma and portal tract) were CD56. In primary biliary cirrhosis specimens, biliary epithelial cells, hepatocytes, and intermediate cells were CD56 distributed as 10 out of 14 cases as stage 1 (71.43%), 18 out of 23 as stage 2 (78.26%), nine out of 14 as stage 3 (64.28%), and two out of two as stage 4 (100%). The total positive cases were 39 of 53 (73.58%). CD56 was expressed equally in all three types of cells. These findings indicate that the consistent and uniform expression of CD56 in biliary epithelial cells, hepatocytes, and intermediate cells during hepatic injury in primary biliary cirrhosis is probably related to cellular damage and may be important in tissue regeneration. Furthermore, we cannot distinguish a specific cell type from the three above mentioned ones (biliary epithelial cells, hepatocytes, intermediate cells) as a putative stem cell in primary biliary cirrhosis.

Malignant transformation of the cultured human normal biliary tract epithelial cells induced by hepatitis C virus core protein

High level expression of hepatitis C virus core protein (HCV-C) was detected in hilar cholangiocarcinoma tissues in our previous studies. This protein played an important role in the process of cancer cell inversion and proliferation, by some direct and indirect effects on certain genes. Based on this observation, we investigated the effect of HCV-C on human normal biliary epithelial (hBE) cell transformation and tumor development. Plasmid pHCV-C encoding the gene of HCV core protein was constructed and transfected into hBE cells. The expression and the biological effect of HCV-C in HCV-C gene-modified hBE cells were determined in vitro and in vivo. The clone formation rates of hBE cells transfected with pHCV-C, pcdna3.1 and mock-transfected cells were 36, 2.5 and 1.5%, respectively. Tumor developed in 7 of 7 nude mice after incubated with pHCV-C transfected hBE cells, while no tumor appeared in mice injected with pcdna3.1- and mock-transfected hBE cells. To investigate the possible mechanism of malignant transformation, we further studied the telomerase activity and human telomerase reverse transcriptase (hTERT) expression in pHCV-C transfected hBE cells. The elevated expression of hTERT was confirmed by RT-PCR, immunocytochemistry (ICC) and Western blot analysis, which in turn elevated the telomerase activity, confirmed by TRAP-ELISA. These results indicated that HCV-C protein could participate in malignant transformation of human normal biliary epithelial cells and induce cholangiocarcinoma tumorigenesis, and the activation of telomerase was one of the possible mechanisms.

Transient transfection of HBV X gene into human normal biliary epithelial cells and its effects on expression of human telomerase reverse transcriptase mRNA

目的 通过研究HBx基因转染到人正常胆管上皮(HBECs)后对人端粒酶逆转录酶(hTERT)基因的转录调节作用,以阐明HBV感染在胆管癌发生中的作用机制.方法瞬时转染HBx基因到体外培养的HBECs,同时转染含增强型绿色荧光蛋白(EGFP)基因的克隆载体以判定转染率;RT-PCR分析转染后HBECs内hTERT mRNA的表达变化;并通过细胞免疫组化技术了解转染细胞内HBx蛋白的表达.结果经EGFP判定的转染率约为15%;未经转染或转染空载体的HBECs不表达hTERT mRNA,而转染HBx基因的HBECs可表达明显的hTERT mRNA;只有在转染了HBx基因的HBECs可检测到HBx蛋白表达.结论 HBx基因转染能激活hTERT mRNA的转录表达,这种顺式调节作用可能是胆管上皮增殖、分化并恶化的主要机制。

Human normal biliary epithelial cells transformation and tumor development induced by hepatitis C virus core protein

To study the effect of hepatitis C virus core protein (HCV-C) on human normal biliary epithelial cells (BEC) transformation and tumor development. BEC cells were transfected with plasmid pcDNA HCV-C (expressing HCV-C) by lipofectamine and selected in G418. The expression of HCV-C gene and protein was determined by PCR and immunohistochemical staining, respectively. Biological effect of transfected cells was observed through cell proliferation assay, anchor independent growth, and tumor development in nude mice. The expression of HCV-C protein in the induced tumor was evaluated by immunohistochemistry. HCV-C was strongly expressed in BEC cells transfected with plasmid pcDNA HCV-C and the positive signal was located in cytoplasm. The HCV-C expression protein in the induced cytoplasm. Cell proliferation assay showed that the population doubling time in the pcDNA HCV-C transfected cells was much shorter than that in the pcDNA3 and non-transfected cells (14 h, 28 h, 30 h respectively). The cloning efficiencies of transfected cells with pcDNA HCV-C, pcDNA3 and non-transfected cells were 36%, 2.5% and 1.5%, respectively (P < 0.01). Tumor developed in nude mice inoculated with pcDNA HCV-C transfected cells after the inoculation. HE staining showed bile duct carcinoma character and immunohistochemistry confirmed HCV-C expression in the tumor tissue. The positive control group also showed tumor development, while no tumor mass obtained in the nude mice inoculated with pcDNA3 and non-transfected cells even 36 days after the injection. HCV-C protein showed human normal biliary epithelial cells transformation and tumorigenic features.

Biliary epithelial cell antibodies induce expression of toll-like receptors 2 and 3: A mechanism for post-liver transplantation cholangitis?

Studies to determine the role of preformed antibodies to biliary epithelial cells (BECs) in liver transplant rejections have been initiated. However, the clinical importance of these antibodies in the posttransplantation period still remains to be elucidated. Reactivity to BECs isolated from a normal healthy liver was investigated in sera of 56 patients before and after liver transplantation (LTX) using flow cytometry. Functional capacity of BEC antibodies was determined by the ability to induce expression of Toll-like receptors (TLRs) on BECs. Cytokine and chemokine production induced by BEC antibodies was determined by enzyme-linked immunosorbent assay. In all, 7 patients (13%) had BEC antibodies only pre-LTX, 14 (25%) only after LTX, 18 (32%) both before and after LTX, and 17 (30%) had no detectable antibodies. Presence of preformed BEC antibodies correlated with acute rejections (P < 0.03). Deposition of immunoglobulins in bile ducts was detected in biopsies of patients during rejections. Significantly higher numbers of patients with post-LTX antibodies (9 of 32) developed cholangitis, compared with 0 of 17 without antibodies (P < 0.02). Specificity studies indicated that these antibodies were both non-HLA- and HLA-specific. Normal BECs expressed mRNA but not the proteins for the TLRs. However, treatment with F(ab')2 fragments of BEC antibodies induced protein expression of TLRs 2 and 3 and significantly high production of interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, macrophage inflammatory protein (MIP)-1alpha, epithelial neutrophil activating peptide (ENA)-78, and IL-8. In conclusion, BEC antibodies via induction of TLR2 and TLR3 expression, as well as inflammatory cytokine and chemokine production may induce epithelial cell inflammatory responses to bacterial components and contribute to posttransplantation cholangitis.

A Crucial Role of Hepatocyte Nuclear Factor-4 Expression in the Differentiation of Human Ductular Hepatocytes

Ductular structures are suggested to be bipotential progenitor cells that may differentiate into hepatocytes or biliary epithelial cells (BEC). To better understand the differentiation process, we studied the expression of hepatocyte nuclear factor (HNF) in ductular structures. Matured hepatocytes in normal liver expressed HNF-1, HNF-4α, HNF-3β, and C/EBPα in the nucleus. Normal BEC expressed HNF-1 but did not express HNF-4α, suggesting an important role of HNF-4α in maintaining the phenotype of matured hepatocytes. Ductular structures were classified into ductular cells and ductular hepatocytes. Ductular cells showed glandular or bile duct-like appearance and strongly expressed cytokeratin-7. Ductular hepatocytes showed features between BEC and hepatocytes and heterogeneously expressed cytokeratin-7. Both ductular cells and ductular hepatocytes expressed HNF-4α, but the nuclear localization of HNF-4α was more prominent in ductular hepatocytes. The expression of HNF-4α mRNA in ductular hepatocytes was demonstrated at the single cell level by laser capture microdissection. Regenerative hepatocytes strongly expressed all HNFs in the nucleus, whereas residual hepatocytes in massive necrosis showed low or cytoplasmic expression. These results suggest that HNF-4α plays an important role in the differentiation and maintenance of the matured hepatocyte phenotype and that nuclear localization of HNFs is implicated in the accomplishment of their function.