Pkd1l1-deficiency drives biliary atresia through ciliary dysfunction in biliary epithelial cells.

BACKGROUND & AIMS: Syndromic biliary atresia is a cholangiopathy characterized by fibro-obliterative changes in the extrahepatic bile duct (EHBD) and congenital malformations including laterality defects. The etiology remains elusive and faithful animal models are lacking. Genetic syndromes provide important clues regarding the pathogenic mechanisms underlying the disease. We investigated the role of the gene Pkd1l1 in the pathophysiology of syndromic biliary atresia. METHODS: Constitutive and conditional Pkd1l1 knockout mice were generated to explore genetic pathology as a cause of syndromic biliary atresia. We investigated congenital malformations, EHBD and liver pathology, EHBD gene expression, and biliary epithelial cell turnover. Biliary drainage was functionally assessed with cholangiography. Histology and serum chemistries were assessed after DDC (3,5-diethoxycarbony l-1,4-dihydrocollidine) diet treatment and inhibition of the ciliary signaling effector GLI1. RESULTS: Pkd1l1-deficient mice exhibited congenital anomalies including malrotation and heterotaxy. Pkd1l1-deficient EHBDs were hypertrophic and fibrotic. Pkd1l1-deficient EHBDs were patent but displayed delayed biliary drainage. Pkd1l1-deficient livers exhibited ductular reaction and periportal fibrosis. After DDC treatment, Pkd1l1-deficient mice exhibited EHBD obstruction and advanced liver fibrosis. Pkd1l1-deficient mice had increased expression of fibrosis and extracellular matrix remodeling genes (Tgfα, Cdkn1a, Hb-egf, Fgfr3, Pdgfc, Mmp12, and Mmp15) and decreased expression of genes mediating ciliary signaling (Gli1, Gli2, Ptch1, and Ptch2). Primary cilia were reduced on biliary epithelial cells and altered expression of ciliogenesis genes occurred in Pkd1l1-deficient mice. Small molecule inhibition of the ciliary signaling effector GLI1 with Gant61 recapitulated Pkd1l1-deficiency. CONCLUSIONS: Pkd1l1 loss causes both laterality defects and fibro-proliferative EHBD transformation through disrupted ciliary signaling, phenocopying syndromic biliary atresia. Pkd1l1-deficient mice function as an authentic genetic model for study of the pathogenesis of biliary atresia. IMPACT AND IMPLICATIONS: The syndromic form of biliary atresia is characterized by fibro-obliteration of extrahepatic bile ducts and is often accompanied by laterality defects. The etiology is unknown, but Pkd1l1 was identified as a potential genetic candidate for syndromic biliary atresia. We found that loss of the ciliary gene Pkd1l1 contributes to hepatobiliary pathology in biliary atresia, exhibited by bile duct hypertrophy, reduced biliary drainage, and liver fibrosis in Pkd1l1-deficient mice. Pkd1l1-deficient mice serve as a genetic model of biliary atresia and reveal ciliopathy as an etiology of biliary atresia. This model will help scientists uncover new therapeutic approaches for patients with biliary atresia, while pediatric hepatologists should validate the diagnostic utility of PKD1L1 variants.

C-X-C motif chemokine ligand 1 induced by Hedgehog signaling promotes mouse extrahepatic bile duct repair after acute injury.

BACKGROUND AND AIMS: In extrahepatic bile duct (EHBD) cholangiopathies, including primary sclerosing cholangitis, a reactive cholangiocyte phenotype is associated with inflammation and epithelial hyperproliferation. The signaling pathways involved in EHBD injury response are poorly understood. In this study, we investigated the role of Hedgehog (HH) signaling and its downstream effectors in controlling biliary proliferation and inflammation after EHBD injury. APPROACH AND RESULTS: Using mouse bile duct ligation as an acute EHBD injury model, we used inhibitory paradigms to uncover mechanisms promoting the proliferative response. HH signaling was inhibited genetically in Gli1-/- mice or by treating wild-type mice with LDE225. The role of neutrophils was tested using chemical (SB225002) and biological (lymphocyte antigen 6 complex locus G6D [Ly6G] antibodies) inhibitors of neutrophil recruitment. The cellular response was defined through morphometric quantification of proliferating cells and CD45+ and Ly6G+ immune cell populations. Key signaling component expression was measured and localized to specific EHBD cellular compartments by in situ hybridization, reporter strain analysis, and immunohistochemistry. Epithelial cell proliferation peaked 24 h after EHBD injury, preceded stromal cell proliferation, and was associated with neutrophil influx. Indian HH ligand expression in the biliary epithelium rapidly increased after injury. HH-responding cells and neutrophil chemoattractant C-X-C motif chemokine ligand 1 (CXCL1) expression mapped to EHBD stromal cells. Inhibition of HH signaling blocked CXCL1 induction, diminishing neutrophil recruitment and the biliary proliferative response to injury. Directly targeting neutrophils by inhibition of the CXCL1/C-X-C motif chemokine receptor 2/Ly6G signaling axis also decreased biliary proliferation. CONCLUSIONS: HH-regulated CXCL1 orchestrates the early inflammatory response and biliary proliferation after EHBD injury through complex cellular crosstalk.

Axin2+ Peribiliary Glands in the Periampullary Region Generate Biliary Epithelial Stem Cells That Give Rise to Ampullary Carcinoma.

BACKGROUND & AIMS: Peribiliary glands (PBGs), clusters of epithelial cells residing in the submucosal compartment of extrahepatic bile ducts, have been suggested as biliary epithelial stem/progenitor cell niche; however, evidence to support this claim is limited because of a lack of PBG-specific markers. We therefore sought to identify PBG-specific markers to investigate the potential role of PBGs as stem/progenitor cell niches, as well as an origin of cancer. METHODS: We examined the expression pattern of the Wnt target gene Axin2 in extrahepatic bile ducts. We then applied lineage tracing to investigate whether Axin2-expressing cells from PBGs contribute to biliary regeneration and carcinogenesis using Axin2-CreERT mice. RESULTS: Wnt signaling activation, marked by Axin2, was limited to PBGs located in the periampullary region. Lineage tracing showed that Axin2-expressing periampullary PBG cells are capable of self-renewal and supplying new biliary epithelial cells (BECs) to the luminal surface. Additionally, the expression pattern of Axin2 and the mature ductal cell marker CK19 were mutually exclusive in periampullary region, and fate tracing of CK19+ luminal surface BECs showed gradual replacement by CK19- cells, further supporting the continuous replenishment of new BECs from PBGs to the luminal surface. We also found that Wnt signal enhancer R-spondin3 secreted from Myh11-expressing stromal cells, corresponding to human sphincter of Oddi, maintained the periampullary Wnt signal-activating niche. Notably, introduction of PTEN deletion into Axin2+ PBG cells, but not CK19+ luminal surface BECs, induced ampullary carcinoma whose development was suppressed by Wnt inhibitor. CONCLUSION: A specific cell population receiving Wnt-activating signal in periampullary PBGs functions as biliary epithelial stem/progenitor cells and also the cellular origin of ampullary carcinoma.

miRNA profiling of biliary intraepithelial neoplasia reveals stepwise tumorigenesis in distal cholangiocarcinoma via the miR-451a/ATF2 axis.

Distal cholangiocarcinoma (dCCA) is a biliary tract cancer with a dismal prognosis and is often preceded by biliary intraepithelial neoplasia (BilIN), representing the most common biliary non-invasive precursor lesion. BilIN are histologically well defined but have not so far been characterised systematically at the molecular level. The aim of this study was to determine miRNA-regulated genes in cholangiocarcinogenesis via BilIN. We used a clinicopathologically well-characterised cohort of 12 dCCA patients. Matched samples of non-neoplastic biliary epithelia, BilIN and invasive tumour epithelia of each patient were isolated from formalin-fixed paraffin-embedded tissue sections by laser microdissection. The resulting 36 samples were subjected to total RNA extraction and the expression of 798 miRNAs was assessed using the Nanostring® technology. Candidate miRNAs were validated by RT-qPCR and functionally investigated following lentiviral overexpression in dCCA-derived cell lines. Potential direct miRNA target genes were identified by microarray and prediction algorithms and were confirmed by luciferase assay. We identified 49 deregulated miRNAs comparing non-neoplastic and tumour tissue. Clustering of these miRNAs corresponded to the three stages of cholangiocarcinogenesis, supporting the concept of BilIN as a tumour precursor. Two downregulated miRNAs, i.e. miR-451a (-10.9-fold down) and miR-144-3p (-6.3-fold down), stood out by relative decrease. Functional analyses of these candidates revealed a migration inhibitory effect in dCCA cell lines. Activating transcription factor 2 (ATF2) and A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) were identified as direct miR-451a target genes. Specific ATF2 inhibition by pooled siRNAs reproduced the inhibitory impact of miR-451a on cancer cell migration. Thus, our data support the concept of BilIN as a direct precursor of invasive dCCA at the molecular level. In addition, we identified miR-451a and miR-144-3p as putative tumour suppressors attenuating cell migration by inhibiting ATF2 in the process of dCCA tumorigenesis. © The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Alterations in chemokine receptor CCR5 activity influence tumor cell biology in human cholangiocarcinoma cell lines.

INTRODUCTION AND OBJECTIVES: Intrahepatic (I-CCA) and extrahepatic (E-CCA) cholangiocarcinoma (CCA) have different growth patterns and risks for tumor metastasis. Inhibition and/or activation of the chemokine receptor CCR subclasses have been reported to alter tumor cell biology in non-CCA cancers. In this study we documented CCR expression profiles in representative human I-CCA and E-CCA cell lines and the in vitro effects of CCR antagonists and agonists on tumor cell biology. MATERIALS AND METHODS: CCR expression profiles were documented by real-time reverse transcription polymerase chain reaction; cell proliferation by WST-1; spheroid formation by sphere dimensions in anchorage-free medium; cell migration by wound healing and invasion by Transwell invasion chambers. RESULTS: All 10 CCR motifs (CCR1-10) were expressed in the I-CCA, HuCCT1 cell line and six (CCR4, 5, 6, 8, 9 and 10) in the E-CCA, KMBC cell line. In HuCCT1 cells, CCR5 expression was most abundant whereas in KMBC cells, CCR6 followed by CCR5 were most abundant. The CCR5 antagonist Maraviroc significantly inhibited cell proliferation, migration and invasion in HuCCT1 cells, and spheroid formation and invasion in KMBC cells. The CCR5 agonist RANTES had no effect on HuCCT1 cells but increased cell proliferation, migration and invasion of KMBC cells. CONCLUSION: These results suggest that CCR expression profiles differ in I-CCA and E-CCA. They also indicate that CCR5 antagonists and agonists have cell-specific effects but in general, CCR5 inactivation inhibits CCA tumor cell aggressiveness. Additional research is required to determine whether CCR5 inactivation is of value in the treatment of CCA in humans.

Characterization of Peribiliary Gland-Constituting Cells Based on Differential Expression of Trophoblast Cell Surface Protein 2 in Biliary Tract.

Peribiliary glands (PBGs) are accessory glands with mucinous and serous acini in the biliary tree. The PBG is composed of a heterogeneous cell population, such as mucus- and pancreatic enzyme-producing epithelial cells, whereas it constitutes niches for multipotential stem/progenitor cells in the human extrahepatic bile duct (EHBD). By contrast, the nature of PBGs in the mouse EHBD remains unclear. Our aim was to establish a method for isolating and characterizing PBG-constituting cells in the mouse EHBD. We found that trophoblast cell surface protein 2 (Trop2) was expressed in the luminal epithelium of mouse EHBD exclusively, but not in the PBG. On the basis of the differential expression profile of Trop2, lumen-forming biliary epithelial cells (LBECs) and PBG-constituting epithelial cells (PBECs) were separately isolated for further characterization. Gene expression analysis revealed that the isolated mouse PBECs expressed several marker genes related to human PBGs. In the colony formation assay, PBECs showed significantly higher colony formation capacity than LBECs. In the organoid formation assay, PBECs formed cystic organoid with LBEC-like phenotype. Interestingly, PBECs proliferated, accompanied by reexpression of Trop2 in vivo after bile duct ligation. Furthermore, the unique expression profile of Trop2 was conserved in human EHBD. Our findings indicate that Trop2 is a useful marker in investigating the pathophysiological roles and characteristics of mouse and human PBGs in biliary diseases.

The toxin biliatresone causes mouse extrahepatic cholangiocyte damage and fibrosis through decreased glutathione and SOX17.

UNLABELLED: Biliary atresia, the most common indication for pediatric liver transplantation, is a fibrotic disease of unknown etiology affecting the extrahepatic bile ducts of newborns. The recently described toxin biliatresone causes lumen obstruction in mouse cholangiocyte spheroids and represents a new model of biliary atresia. The goal of this study was to determine the cellular changes caused by biliatresone in mammalian cells that ultimately lead to biliary atresia and extrahepatic fibrosis. We treated mouse cholangiocytes in three-dimensional (3D) spheroid culture and neonatal extrahepatic duct explants with biliatresone and compounds that regulate glutathione (GSH). We examined the effects of biliatresone on SOX17 levels and determined the effects of Sox17 knockdown on cholangiocytes in 3D culture. We found that biliatresone caused disruption of cholangiocyte apical polarity and loss of monolayer integrity. Spheroids treated with biliatresone had increased permeability as shown by rhodamine efflux within 5 hours compared with untreated spheroids, which retained rhodamine for longer than 12 hours. Neonatal bile duct explants treated with the toxin showed lumen obstruction with increased subepithelial staining for α-smooth muscle actin and collagen, consistent with fibrosis. Biliatresone caused a rapid and transient decrease in GSH, which was both necessary and sufficient to mediate its effects in cholangiocyte spheroid and bile duct explant systems. It also caused a significant decrease in cholangiocyte levels of SOX17, and Sox17 knockdown in cholangiocyte spheroids mimicked the effects of biliatresone. CONCLUSION: Biliatresone decreases GSH and SOX17 in mouse cholangiocytes. In 3D cell systems, this leads to cholangiocyte monolayer damage and increased permeability; in extrahepatic bile duct explants, it leads to disruption of the extrahepatic biliary tree and subepithelial fibrosis. This mechanism may be important in understanding human biliary atresia. (Hepatology 2016;64:880-893).

Alteration of amino acid and biogenic amine metabolism in hepatobiliary cancers: Findings from a prospective cohort study.

Perturbations in levels of amino acids (AA) and their derivatives are observed in hepatocellular carcinoma (HCC). Yet, it is unclear whether these alterations precede or are a consequence of the disease, nor whether they pertain to anatomically related cancers of the intrahepatic bile duct (IHBC), and gallbladder and extrahepatic biliary tract (GBTC). Circulating standard AA, biogenic amines and hexoses were measured (Biocrates AbsoluteIDQ-p180Kit) in a case-control study nested within a large prospective cohort (147 HCC, 43 IHBC and 134 GBTC cases). Liver function and hepatitis status biomarkers were determined separately. Multivariable conditional logistic regression was used to calculate odds ratios and 95% confidence intervals (OR; 95%CI) for log-transformed standardised (mean = 0, SD = 1) serum metabolite levels and relevant ratios in relation to HCC, IHBC or GBTC risk. Fourteen metabolites were significantly associated with HCC risk, of which seven metabolites and four ratios were the strongest predictors in continuous models. Leucine, lysine, glutamine and the ratio of branched chain to aromatic AA (Fischer's ratio) were inversely, while phenylalanine, tyrosine and their ratio, glutamate, glutamate/glutamine ratio, kynurenine and its ratio to tryptophan were positively associated with HCC risk. Confounding by hepatitis status and liver enzyme levels was observed. For the other cancers no significant associations were observed. In conclusion, imbalances of specific AA and biogenic amines may be involved in HCC development.

Cholangiocarcinoma Heterogeneity Revealed by Multigene Mutational Profiling: Clinical and Prognostic Relevance in Surgically Resected Patients.

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.

Extrahepatic platelet-derived growth factor-ß, delivered by platelets, promotes activation of hepatic stellate cells and biliary fibrosis in mice.

BACKGROUND & AIMS: Platelet-derived growth factor-ß (PDGFB) is a mitogen for hepatic stellate cells (HSCs). We studied the cellular sources of PDGFB and the effects of a high-affinity monoclonal antibody against PDGFB (MOR8457) in mouse models of biliary fibrosis. METHODS: Cellular sources of PDGFB were identified using quantitative reverse-transcription polymerase chain reaction, biochemical, and immunohistologic methods. Mice with advanced biliary fibrosis, MDR2(Abcb4)-null mice, and C57Bl/6 (control) mice were placed on 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-supplemented diets and were given weekly intraperitoneal injections of MOR8457. Platelets were depleted from MDR2-null mice by injection of an antibody against CD41, or inhibited with diets containing low-dose aspirin. Liver tissues were collected and analyzed by quantitative reverse-transcription PCR and histologic and biochemical analyses. RESULTS: Levels of PDGFB protein, but not messenger RNA, were increased in fibrotic livers of MDR2-null mice, compared with control mice. Platelet clusters were detected in the hepatic endothelium, in close proximity to HSCs, and were identified as a source of PDGFB protein in MDR2-null mice. Levels of the PDGFB were increased in serum samples from patients with early stages of liver fibrosis of various etiologies (F1-2, n = 16; P < .05), compared with nonfibrotic liver tissue (F0, n = 12). Depletion of platelets from MDR2-null mice normalized hepatic levels of PDGFB within 48 hours, reducing levels of a marker of HSC activation (α-smooth muscle actin) and expression of genes that promote fibrosis. Diets supplemented with low-dose aspirin reduced circulating serum and hepatic levels of PDGFB and significantly reduced progression of fibrosis in MDR2-null mice over 1 year. MOR8457 produced a dose-dependent decrease in liver fibrosis in MDR2-null mice, reducing collagen deposition by 45% and expression of fibrosis-associated genes by 50%, compared with mice given a control antibody. In vitro, platelets activated freshly isolated HSCs (induction of α-smooth muscle actin and fibrosis-associated genes) via a PDGFB-dependent mechanism. MOR8457 also reduced liver fibrosis in mice placed on DDC-supplemented diets. CONCLUSIONS: Platelets produce PDGFB to activate HSC and promote fibrosis in MDR2-null mice and mice on DDC-supplemented diets. Antiplatelet therapy or selective inhibition of PDGFB might reduce biliary fibrosis in patients with liver disease.

Molecular profiling of intrahepatic and extrahepatic cholangiocarcinoma using next generation sequencing.

Cholangiocarcinoma is a heterogeneous malignant process, which is further classified into intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC). The poor prognosis of the disease is partly due to the lack of understanding of the disease mechanism. Multiple gene alterations identified by various molecular techniques have been described recently. As a result, multiple targeted therapies for ICC and ECC are being developed. In this study, we identified and compared somatic mutations in ICC and ECC patients using next generation sequencing (NGS) (Ampliseq Cancer Hotspot Panel v2 and Ion Torrent 318v2 chips). Eleven of 16 samples passed internal quality control established for NGS testing. ICC cases (n=3) showed IDH1 (33.3%) and NRAS (33.3%) mutations. Meanwhile, TP53 (75%), KRAS (50%), and BRAF (12.5%) mutations were identified in ECC cases (n=8). Our study confirmed the molecular heterogeneity of ICC and ECC using NGS. This information will be important for individual patients as targeted therapies for ICC and ECC become available in the future.

Genome wide DNA copy number analysis in cholangiocarcinoma using high resolution molecular inversion probe single nucleotide polymorphism assay.

In order to study molecular similarities and differences of intrahepatic (IH-CCA) and extrahepatic (EH-CCA) cholangiocarcinoma, 24 FFPE tumor samples (13 IH-CCA, 11 EH-CCA) were analyzed for whole genome copy number variations (CNVs) using a new high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay. Common in both tumor subtypes the most frequent losses were detected on chromosome 1p, 3p, 6q and 9 while gains were mostly seen in 1q, 8q as well as complete chromosome 17 and 20. Applying the statistical GISTIC (Genomic Identification of Significant Targets in Cancer) tool we identified potential novel candidate tumor suppressor- (DBC1, FHIT, PPP2R2A) and oncogenes (LYN, FGF19, GRB7, PTPN1) within these regions of chromosomal instability. Next to common aberrations in IH-CCA and EH-CCA, we additionally found significant differences in copy number variations on chromosome 3 and 14. Moreover, due to the fact that mutations in the Isocitrate dehydrogenase (IDH-1 and IDH-2) genes are more frequent in our IH-CCA than in our EH-CCA samples, we suggest that the tumor subtypes have a different molecular profile. In conclusion, new possible target genes within regions of high significant copy number aberrations were detected using a high-density Molecular Inversion Probe Single Nucleotide Polymorphism (MIP SNP) assay, which opens a future perspective of fast routine copy number and marker gene identification for gene targeted therapy.

Cystadenomas of the liver and extrahepatic bile ducts: Morphologic and immunohistochemical characterization of the biliary and intestinal variants.

Cystadenomas of the liver and extrahepatic bile ducts (EHBD) are uncommon but distinctive neoplasms whose terminology and epithelial phenotype have been a source of controversy. We reviewed 20 cases, 16 arising in the liver and 4 in the EHBD. Eighteen patients were women, with a mean age of 36.5 years. Eighteen tumors were multiloculated and 2 were unilocular. The tumor size ranged from 4 to 29 cm (average, 11 cm). The cyst fluid in 13 tumors was described as serous, in 2 as clear, in 2 others as hemorrhagic, and in 1 as serous and mucinous. Only in 2 tumors was the fluid described as mucinous. In 18 cystadenomas, the predominant epithelial lining consisted of a single layer of cuboidal or low-columnar nondysplastic cells similar to those of the gallbladder or bile ducts. This epithelial lining was strongly positive for cytokeratins 7 and 19, and focally positive for MUC1. Only 2 cystadenomas showed predominant intestinal differentiation characterized by mature goblet cells and columnar absorptive cells. These cells expressed CDX2, MUC2, and cytokeratin 20. Admixed with the goblet and columnar cells, there were serotonin-containing cells and Paneth cells. These 2 tumors showed extensive areas of high-grade dysplasia and invasive adenocarcinoma with intestinal phenotype. A subepithelial ovarian-like stroma was present in all tumors. None of the patients died of the tumors. We believe that the term mucinous cystic tumor recommended by the World Health Organization for all cystadenomas of the liver and EHBD is a misnomer.

Prognostic significance of epithelial-mesenchymal transition-related markers in extrahepatic cholangiocarcinoma: comprehensive immunohistochemical study using a tissue microarray.

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.

SOX4 is associated with poor prognosis in cholangiocarcinoma.

Overexpressions of EGFR and HER2 are thought to be prognostic factors of cholangiocarcinoma (CCA). The SOX4 transcription factor is involved in the development and cell fate decision. Although up-regulation of SOX4 has been described in multiple human malignancies, the prognostic value of SOX4 and its relationship to EGFR/HER2 in CCA remain unclear. In the current study, we showed that SOX4 and EGFR were overexpressed in 17 (29.3%), and 13 (22.4%) of the 58 intrahepatic cholangiocarcinomas (IHCCs), as well as 28 (29.8%), and 33 (35.1%) of the 94 extrahepatic cholangiocarcinomas (EHCCs), respectively. Overexpression of HER2 was exclusively identified in EHCCs, with the rate being 4.4% (4/90). In all, amplification of EGFR was identified in 1.8% (1/52) of IHCC cases, and in 2% (3/82) of EHCC cases. By contrast, HER2 amplification was present only in 3.5% (3/94) of the EHCC cases. Notably, Kaplan-Meier survival analysis suggested that SOX4 expression is a significant prognostic factor for poor prognosis in IHCC patients. Importantly, our findings suggested significant association of SOX4 and EGFR expression both in IHCC (P<0.001) and EHCC (P=0.014). SOX4 may modulate expression of EGFR, and SOX4+/EGFR+ defines a subset of CCA patients with poor prognosis. Finally, in vitro data indicated that SOX4 inhibits cellular migratory capacity and promotes epithelial-mesenchymal transition (EMT) process of CCA cells. Collectively, our results define an important role for SOX4 in CCA by orchestrating EMT and modulation on EGFR expression. SOX4 expression may serve as a prognostic marker for patients with IHCC.

A novel model for orthotopic liver transplantation in rats using hepatic rearterialization and biliary extradrainage system.

BACKGROUND: Although the rat orthotopic liver transplantation (OLT) model has existed for many years, only a few models can be applied for dynamic bile collection. The aim of this study was to introduce a dependent rat OLT model with hepatic rearterialization and an expediently dynamic bile collection system. METHODS: Forty-five male Sprague-Dawley rats were divided into the following three groups (n = 15 each): group A, OLT without hepatic rearterialization; group B, OLT with hepatic rearterialization; group C, OLT with hepatic rearterialization and a biliary extradrainage system. In groups B and C, a modified sleeve anastomosis between the donor common hepatic artery and the recipient proper hepatic artery was performed to restore the hepatic artery blood flow. In group C, after hepatic rearterialization, biliary extradrainage and jejunum stoma were performed to reestablish the bile flow, and a waistcoat-like external fixator was introduced to protect this system. RESULTS: The surgical success rates in groups A, B, and C were 100% (15/15), 93% (14/15), and 93% (14/15), respectively. In groups B and C, the hepatic artery patency rates were 93% and 86% on postoperative day 3 and postoperative day 21, respectively. Also, the liver function and bile duct integrity were preserved better than that in group A. In group C, the biliary extradrainage system was well preserved and bile collection was easily performed. CONCLUSIONS: The rat OLT model with hepatic rearterialization and a convenient biliary extradrainage system was satisfactory in maintaining the survival rate, hepatic artery patency rate, and recovery of graft function, so it can be applied in various studies after transplantation.

Quantitative analysis of VEGF-C mRNA of extrahepatic cholangiocarcinoma with real-time PCR using samples obtained during endoscopic retrograde cholangiopancreatography.

OBJECTIVE: Vascular endothelial growth factor (VEGF)-C overexpression in extrahepatic cholangiocarcinoma (ECC) has been shown to be correlated with lymph node metastasis. The intensity of immunohistochemical staining of VEGF-C protein in surgical samples has been used as index of VEGF-C overexpression in previous studies. The aim of the study was to examine if VEGF-C overexpression in ECC could be preoperatively detected by using samples obtained during ERCP. METHODS: Consecutive patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) for biliary stricture during the study period were prospectively analyzed. VEGF-C mRNA was quantified by real-time PCR methods using endoscopic samples obtained during ERCP. The high intensity of immunohistochemical staining of VEGF-C protein in surgical samples was used for the reference standard of VEGF-C overexpression. The level of S100P mRNA which was a novel diagnostic marker of ECC was also quantified to evaluate whether the endoscopic samples contained ECC cells. RESULTS: Twenty-five patients were enrolled in this study. Eighteen patients were diagnosed as ECC and seven patients were diagnosed as benign biliary structure. Nine of eighteen patients with ECC, who showed positive S100P mRNA in endoscopic samples and received surgical resection, were finally analyzed. Receiver operating characteristics analysis yielded VEGF-C mRNA cut-off value of 3.85 for detection of VEGF-C overexpression, and the diagnostic performance of VEGF-C mRNA measurement in the endoscopic sample for VEGF-C overexpression reached sensitivity of 75.0%, specificity of 100%, and accuracy of 88.9%. CONCLUSION: The quantification of VEGF-C mRNA of ECC with real-time PCR using endoscopic samples was useful for preoperative detection of VEGF-C overexpression.

Extrahepatic cholangiocyte cilia are abnormal in biliary atresia.

OBJECTIVES: Biliary atresia (BA) is a rapidly progressive form of biliary fibrosis affecting neonates. We previously reported that primary cilia on the intrahepatic cholangiocytes of patients with both syndromic and nonsyndromic BA were structurally abnormal. Our objective was to determine whether extrahepatic cholangiocytes in human biliary atresia, intrahepatic and extrahepatic cholangiocytes of rhesus rotavirus (RRV)-infected neonatal mice, and RRV-infected primary neonatal extrahepatic cholangiocytes also demonstrate ciliary abnormalities. METHODS: The livers of neonatal BALB/c mice injected with RRV that developed jaundice, human extrahepatic bile duct samples obtained at time of hepatoportoenterostomy, and RRV-infected primary neonatal cholangiocytes were stained with antibodies against acetylated α tubulin to identify primary cilia. RESULTS: Extrahepatic cholangiocytes from RRV-treated mice demonstrated minimal loss of primary cilia at day 3 but almost complete loss at day 8 and partial loss at day 12. No changes were seen in mouse intrahepatic bile ducts at any of the time points. In the human BA samples, primary cilia were almost completely absent from extrahepatic duct cholangiocytes. There were, however, abundant cilia in the peribiliary glands adjacent to extrahepatic ducts in the BA sample. Cilia in RRV-infected primary neonatal cholangiocytes were significantly decreased compared with controls. CONCLUSIONS: Primary cilia are selectively lost from neonatal extrahepatic but not intrahepatic cholangiocytes after RRV infection in BALB/c mice. The cilia are also decreased in RRV-infected primary cholangiocytes and the extrahepatic ducts from human patients with BA. This suggests that ciliary abnormalities are part of the pathophysiology of BA.

Targeting PDGFR-ß in Cholangiocarcinoma.

BACKGROUND: Cholangiocarcinomas (CCAs) are highly desmoplastic neoplasms with a tumour microenvironment plentiful in myofibroblasts (MFBs). MFB-derived PDGF-BB survival signalling is a mediator of CCA cell resistance to apoptotic stimuli. This raises the concept that targeting PDGFR-ß, a cognate receptor of PDGF-BB, represents a potential strategy for the treatment of human CCA. AIMS: Herein, we examine a role for inhibiting PDGFR-ß in restoring CCA cell sensitivity to apoptotic stimuli in vitro and in vivo. METHODS: We employed human CCA samples from 41 patients (19 intrahepatic and 22 extrahepatic CCA samples), the human CCA cell lines KMCH-1 and HUCCT-1 as well as shPDGFR-ß-KMCH-1 and human myofibroblastic LX-2 cells for these studies. In vivo-experiments were conducted using a syngeneic rat orthotopic CCA model. RESULTS: Of several MFB-derived growth factors profiled, PDGF-BB and CTGF were most abundantly expressed; however, only PDGF-BB attenuated tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) cytotoxicity. Co-culturing CCA cells with PDGF-BB-secreting MFBs significantly decreased TRAIL-induced CCA cell apoptosis when compared with monoculture conditions; this cytoprotective effect was abrogated in the presence of the tyrosine kinase inhibitors imatinib mesylate or linifanib, which inhibit PDGFR-ß. Consistent with these findings, MFB-imparted cytoprotection also was abolished when PDGFR-ß was knocked down as demonstrated in shPDGFR-ß-KMCH-1 cells. Finally, administration of imatinib mesylate increased CCA cell apoptosis and reduced tumour growth in a rodent in vivo-CCA model that mimics the human disease. CONCLUSIONS: Targeting PDGFR-ß sensitizes CCA cells to apoptotic stimuli and appears to be therapeutic in vivo.

Combinatory effects of hepatic CD8+ and NK lymphocytes in bile duct injury from biliary atresia.

INTRODUCTION: To our knowledge, elucidating the immune pathogenesis of disease, especially characteristic T-cell and natural killer (NK) cell expansions, has not been performed before now. We investigated the role of T lymphocytes and NK lymphocytes in the destruction of extrahepatic bile ducts of patients with biliary atresia. METHODS: Lymphocytes from the liver and extrahepatic bile duct remnants of patients with biliary atresia were characterized by immunofluorescence staining, fluorescence-activated cell sorter analysis, and real-time reverse-transcriptase PCR. Cholangiocyte lysis assays were performed to confirm cytotoxicity of activated hepatic NK lymphocytes or CD8(+) cells. RESULTS: The inflammatory milieu from portal tracts and/or biliary remnants consisted of greater numbers of Kupffer cells, T lymphocytes, and NK lymphocytes in the patients with biliary atresia as compared with the cholestatic and noncholestatic controls. In patients with biliary atresia, expression of NK or CD8+ costimulatory molecules was upregulated as compared with controls. Hepatic NK lymphocytes or CD8(+) cells from patients with biliary atresia were demonstrated to be cytotoxic to the duct epithelium. DISCUSSION: Specific immune responses from NK and CD8(+) cells were involved in the injury to the duct epithelium and play a significant role in the phenotype of experimental biliary atresia.