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Background Cholangiocarcinoma can be classified in intrahepatic cholangiocarcinoma (ICC) and perihilar cholangiocarcinoma (PCC). Moreover, PCC includes two different forms: extrahepatic (EH) PCC, which arises from the perihilar EH large ducts, and intrahepatic (IH) PCC, in which a significant liver mass invades the perihilar bile ducts. In this study, we investigated the molecular profile and molecular prognostic factors in EH-PCC, IH-PCC, and ICC submitted to curative surgery. Methods Ninety-one patients with cholangiocarcinoma (38 EH-PCC, 18 IH-PCC, and 35 ICC), who underwent curative surgery in a single tertiary hepatobiliary surgery referral center were assessed for mutational status in 56 cancer-related genes. Results The most frequently mutated genes in EH-PCC were KRAS (47.4 %), TP53 (23.7 %) and ARID1A (15.8 %); in IH-PCC were KRAS (22.2 %), PBRM1 (16.7 %), and PIK3CA (16.7 %); and in ICC were IDH1 (17.1 %), NRAS (17.1 %), and BAP1 (14.3 %). The presence of mutations in ALK , IDH1 , and TP53 genes was significantly associated with poor prognosis in patients with EH-PCC ( p  < 0.001, p  = 0.043, and p  = 0.019, respectively). Mutation of the TP53 gene was significantly associated with poor prognosis in patients with IH-PCC ( p  = 0.049). The presence of mutations in ARID1A , PIK3C2G , STK11 , TGFBR2 , and TP53 genes was significantly associated with poor prognosis in patients with ICC ( p  = 0.012, p  = 0.030, p  = 0.030, p  = 0.011, and p  = 0.011, respectively). Conclusions Mutational gene profiling identified different gene mutations in EH-PCC, IH-PCC, and ICC. Moreover, our study reported specific prognostic genes that can identify patients with poor prognosis after curative surgery who may benefit from traditional or target adjuvant treatments.

Background: Cholangiocarcinoma (CC) is a highly malignant carcinoma. We attempted to clarify the prognostic significance of c-Met overexpression and its association with clinicopathological factors in patients with CC. Patients and methods: One hundred and eleven patients with intrahepatic CC (IHCC) and 136 patients with extrahepatic CC (EHCC) who had undergone curative surgery were divided immunohistologically into c-Met high and c-Met low groups. Clinicopathological factors and outcomes were compared between the groups. c-Met and epidermal growth factor receptor (EGFR) expression was also examined in 10 CC cell lines. Results: The positivity of c-Met was 45.0% in IHCC and 68.4% in EHCC; c-Met high expression was demonstrated in 11.7% of IHCC and 16.2% of EHCC. c-Met high expression was significantly correlated with the 5-year survival rate for CC overall ( P =0.0046) and for IHCC ( P =0.0013), histopathological classification in EHCC, and for EGFR overexpression in both IHCC and EHCC. Coexpression and coactivation of c-Met and EGFR were also observed in CC cell lines. Multivariate analysis revealed that c-Met high expression was an independent predictor of poor overall and disease-free survival in patients with IHCC. Conclusions: c-Met overexpression is associated with EGFR expression and is a poor prognostic factor in CC.

Background: Epithelial–mesenchymal transition (EMT) is characterised by the loss of cell-to-cell adhesion and gaining of mesenchymal phenotypes. Epithelial–mesenchymal transition is proposed to occur in various developmental processes and cancer progression. ‘Cadherin switch’, a process in which cells shift to express different isoforms of the cadherin transmembrane protein and usually refers to a switch from the expression of E-cadherin to N-cadherin, is one aspect of EMT and can have a profound effect on tumour invasion/metastasis. The aim of this study was to investigate the clinicopathological significance of EMT-related proteins and cadherin switch in extrahepatic cholangiocarcinoma (EHCC). Methods: We investigated the association between altered expression of 12 EMT-related proteins and clinical outcomes in patients with EHCC ( n =117) using immunohistochemistry on tissue microarrays. Results: Univariate and multivariate analyses revealed that, in addition to N classification ( P =0.0420), the expression of E-cadherin ( P =0.0208), N-cadherin ( P =0.0038) and S100A4 ( P =0.0157) was each an independent and a significant prognostic factor. We also demonstrated that cadherin switch was independently associated with poor prognosis ( P =0.0143) in patients with EHCC. Conclusions: These results may provide novel information for selection of patients with EHCC who require adjuvant therapy and strict surveillance.

Biliary atresia is a neonatal liver disease with extrahepatic bile duct obstruction and progressive liver fibrosis. The etiology and pathogenesis of the disease are unknown. We previously identified a plant toxin, biliatresone, responsible for biliary atresia in naturally-occurring animal models, that causes cholangiocyte destruction in in-vitro models. Decreases in reduced glutathione (GSH) mimic the effects of biliatresone, and agents that replenish cellular GSH ameliorate the effects of the toxin. The goals of this study were to define signaling pathways downstream of biliatresone that lead to cholangiocyte destruction and to determine their relationship to GSH. Using cholangiocyte culture and 3D cholangiocyte spheroid cultures, we found that biliatresone and decreases in GSH upregulated RhoU/Wrch1, a Wnt signaling family member, which then mediated an increase in Hey2 in the NOTCH signaling pathway, causing downregulation of the transcription factor Sox17. When these genes were up- or down-regulated, the biliatresone effect on spheroids was phenocopied, resulting in lumen obstruction. Biopsies of patients with biliary atresia demonstrated increased RhoU/Wrch1 and Hey2 expression in cholangiocytes. We present a novel pathway of cholangiocyte injury in a model of biliary atresia, which is relevant to human BA and may suggest potential future therapeutics.

Biliary obstruction and cholangiocyte hyperproliferation are important features of cholangiopathies affecting the large extrahepatic bile duct (EHBD). The mechanisms underlying obstruction-induced cholangiocyte proliferation in the EHBD remain poorly understood. Developmental pathways, including WNT signaling, are implicated in regulating injury responses in many tissues, including the liver. To investigate the contribution of WNT signaling to obstruction-induced cholangiocyte proliferation in the EHBD, we used complementary in vivo and in vitro models with pharmacologic interventions and transcriptomic analyses. To model obstruction, we used bile duct ligation (BDL) in mice. Human and mouse biliary organoids and mouse biliary explants were used to investigate the effects of WNT activation and inhibition in vitro. We observed an upregulation of WNT ligand expression associated with increased biliary proliferation following obstruction. Cholangiocytes were identified as both WNT ligand-expressing and WNT-responsive cells. Inhibition of WNT signaling decreased cholangiocyte proliferation in vivo and in vitro, while activation increased proliferation. WNT effects on cholangiocyte proliferation were β-catenin dependent, and we showed a direct effect of WNT7B on cholangiocyte growth. Our studies suggested that cholangiocyte-derived WNT ligands can activate WNT signaling to induce proliferation after obstructive injury. These findings implicate the WNT pathway in injury-induced cholangiocyte proliferation within the EHBD.

Mesothelin is expressed in various types of malignant tumors, and we recently reported that the expression of mesothelin was related to unfavorable patient outcome in pancreatic ductal adenocarcinoma and gastric adenocarcinoma. In this study, we examined the clinicopathological significance of mesothelin expression in extrahepatic bile duct cancer (EHBDCA), especially in terms of its association with the staining pattern. Tissue samples from 61 EHBDCA (16 hilar cholangiocarcinoma, 17 upper bile duct adenocarcinoma, 20 middle bile duct adenocarcinoma and 8 distal bile duct adenocarcinoma) were immunohistochemically examined. The expression levels of mesothelin in tumor cells was classified into the localization of mesothelin in luminal membrane and/or cytoplasm, in addition to high and low according to the staining intensity and proportion as a conventional analysis. 'High-level expression' of mesothelin (47.5%) was statistically correlated with liver metastasis (P=0.013) and poorer patient outcome (P=0.022), while 'luminal membrane positive' of mesothelin (52.5%) was more significantly correlated with liver metastasis (P=0.006), peritoneal metastasis (P=0.024) and unfavorable patient outcome (P=0.017). Moreover, we found that 'cytoplasmic expression' isolated from 'luminal membrane negative' of mesothelin represented the best patient prognosis throughout this study. We describe the expression pattern level of mesothelin, i.e., in luminal membrane or cytoplasm both high and low level, evidently indicate the patient prognosis of EHBDCA, suggesting the pivotal role of mesothelin in cancer promotion depending on its intracellular localization.

Recent studies indicate that tumor suppressor genes can be epigenetically silenced through promoter hypermethylation. To further understand epigenetic alterations in cholangiocarcinoma, we have studied the methylation profiles of 12 candidate tumor suppressor genes (APC, E-cadherin/CDH1, MGMT, RASSF1A, GSTP, RAR-β, p14ARF, p15INK4b, p16INK4a, p73, hMLH1 and DAPK) in 72 cases of cholangiocarcinoma, including equal number cases of intrahepatic cholangiocarcinoma and extrahepatic cholangiocarcinoma. A total of 10 cases of benign biliary epithelia were included as controls. The methylation status of tumor suppressor genes was analyzed using methylation-specific PCR. We found that 85% of all cholangiocarcinomas had methylation of at least one tumor suppressor gene. The frequency of tumor suppressor gene methylation in cholangiocarcinoma was: RASSF1A (65%), p15INK4b (50%), p16INK4a (50%), APC (46%), E-cadherin/CDH1 (43%), p14ARF (38%), p73 (36%), MGMT (33%), hMHL1 (25%), GSTP (14%), RAR-β (14%) and DAPK (3%). Although single tumor suppressor gene methylation can be seen in benign biliary epithelium, methylation of multiple tumor suppressor genes is only seen in cholangiocarcinoma. About 70% (50/72) of the cholangiocarcinomas had three or more tumor suppressor genes methylated and 52% (38/72) of cases had four or more tumor suppressor genes methylated. Concerted methylation of multiple tumor suppressor genes was closely associated with methylation of RASSF1A, p16 and/or hMHL1. Methylation of RASSF1A was more common in extrahepatic cholangiocarcinoma than intrahepatic cholangiocarcinoma (83 vs 47%, P=0.003) while GSTP was more frequently seen in intrahepatic compared to extrahepatic cholangiocarcinoma (31 vs 6%, P=0.012). Our study indicates that methylation of promoter CpG islands of tumor suppressor genes is a common epigenetic event in cholangiocarcinoma. Based on distinct methylation profiles, intrahepatic cholangiocarcinoma and extrahepatic cholangiocarcinoma are two closely related but biologically unique neoplastic processes. Taking advantage of the unique concurrent methylation profile of multiple genes in cholangiocarcinoma may facilitate the distinction of cholangiocarcinoma from benign biliary epithelium in clinical settings.

Extramedullary hematopoietic cells are present in the liver of normal neonates in the first few days of life and persist in infants with biliary atresia. Based on a previous report that liver genes are enriched by erythroid pathways, we examined the liver gene expression pattern at diagnosis and found the top 5 enriched pathways are related to erythrocyte pathobiology in children who survived with the native liver beyond 2 years of age. Using immunostaining, anti-CD71 antibodies identified CD71+ erythroid cells among extramedullary hematopoietic cells in the livers at the time of diagnosis. In mechanistic experiments, the preemptive antibody depletion of hepatic CD71+ erythroid cells in neonatal mice rendered them resistant to rhesus rotavirus-induced (RRV-induced) biliary atresia. The depletion of CD71+ erythroid cells increased the number of effector lymphocytes and delayed the RRV infection of livers and extrahepatic bile ducts. In coculture experiments, CD71+ erythroid cells suppressed the activation of hepatic mononuclear cells. These data uncover an immunoregulatory role for CD71+ erythroid cells in the neonatal liver.

Mutations in SPINT2 encoding the epithelial serine protease inhibitor hepatocyte growth factor activator inhibitor-2 (HAI-2) are associated with congenital tufting enteropathy. However, the functions of HAI-2 in vivo are poorly understood. Here we used tamoxifen-induced Cre-LoxP recombination in mice to ablate Spint2 . Mice lacking Spint2 died within 6 days after initiating tamoxifen treatment and showed severe epithelial damage in the whole intestinal tracts, and, to a lesser extent, the extrahepatic bile duct. The intestinal epithelium showed enhanced exfoliation, villous atrophy, enterocyte tufts and elongated crypts. Organoid crypt culture indicated that Spint2 ablation induced Epcam cleavage with decreased claudin-7 levels and resulted in organoid rupture. These organoid changes could be rescued by addition of serine protease inhibitors aprotinin, camostat mesilate and matriptase-selective α-ketobenzothiazole as well as by co-deletion of Prss8 , encoding the serine protease prostasin. These results indicate that HAI-2 is an essential cellular inhibitor for maintaining intestinal epithelium architecture. Makiko Kawaguchi et al. developed an inducible Spint2 knockout mouse model which exhibited extensive damage to the intestinal epithelium and resulted in death six days after tamoxifen-induced gene ablation. The extreme phenotype observed in this inducible line suggests an important role for Spint2 in maintenance of healthy intestinal epithelium.

Objectives This study explored the expression and function of Slug in human extrahepatic hilar cholangiocarcinoma (EHC) to identify its role in tumor progression. Methods The expression of Snail and Slug mRNA in 52 human tissue samples of EHC was investigated. The mRNA of Snail and Slug were quantified using reverse transcriptase-PCR, and correlations with E-cadherin expression and clinicopathological factors were investigated. We then investigated transfection of Slug cDNA in endogenous E-cadherin-positive human EHC FRH0201 cells, selectively induced the loss of E-cadherin protein expression, and then small interfering RNA (siRNA) for inhibition of Slug expression in endogenous Slug-positive human EHC QBC939 cells, selectively induced the loss of Slug protein expression. A Boyden chamber transwell assay was used for invasion. Results Slug mRNA was overexpressed in 18 cases (34.6%) of EHC compared with adjacent noncancerous tissue. E-Cadherin protein expression determined in the same 52 cases by immunohistochemistry was significantly down-regulated in those cases with Slug mRNA overexpression (P = 0.0001). The tumor and nontumor ratio of Slug mRNA was correlated with nodal metastasis(p = 0.0102), distant metastasis (p = 0.0001)and Survival time(p = 0.0443). However, Snail mRNA correlated with neither E-cadherin expression nor tumor invasiveness. By inhibiting Slug expression by RNA interference, we found that reduced Slug levels upregulated E-cadherin and decreased invasion in QBC939 cell. When the QBC939 cells was infected with Slug cDNA,, significant E-cadherin was downregulated and increased invasion in QBC939 cell. Conclusions The results suggested that Slug expression plays an important role in both the regulation of E-cadherin expression and in the acquisition of invasive potential in human EHC. Slug is possibly a potential target for an antitumor therapy blocking the functions of invasion and metastasis in human EHCs.