Enhanced epidermal growth factor receptor activation in human cholangiocarcinoma cells

Buparlisib and ponatinib inhibit aggressiveness of cholangiocarcinoma cells via suppression of IRS1-related pathway by targeting oxidative stress resistance

Cholangiocarcinoma (CCA) is an oxidative stress-driven liver cancer with bile duct epithelial cell phenotypes and currently lacks effective treatments, making targeted drug therapy urgently needed. Oxidative stress plays a critical role in CCA carcinogenesis, involving cells with oxidative stress resistance via upregulation of the PI3K and MEKK3 signaling pathways. In this study, we investigated the antineoplastic efficacy of a PI3K inhibitor (buparlisib) and a multi-tyrosine kinase inhibitor (ponatinib) on CCA. The cytotoxicity of the drug combination was studied in vitro using CCA cell lines and in vivo using CCA xenograft models. It was found that the drug combination suppressed growth, colony formation, and migration abilities of CCA cells and induced oxidative damage, cell cycle arrest, and autophagy by suppressing MEKK3 and YAP1 through inhibition of insulin receptor substrate 1 (IRS1) signaling. Moreover, the drugs would potentially bind to the IRS1 protein, significanly decreasing IRS1 phosphorylation. Additionally, the drug combination significantly diminished the expression of YAP1, the cell proliferation marker and an antioxidant regulator, and increased oxidative stress-responsive markers in the xenograft model. In conclusion, targeting oxidative stress resistance with combined buparlisib and ponatinib suppressed tumor growth and migration by repressing IRS1-related pathways and ultimately inducing oxidative damage, suggesting the potential for targeted therapy and clinical trials in CCA patients over the use of a single drug.

Cholangiocyte ciliary defects induce sustained epidermal growth factor receptor signaling

BACKGROUND AND AIMS

The primary cilium, an organelle that protrudes from cell surfaces, is essential for sensing extracellular signals. With disturbed cellular communication and chronic liver pathologies, this organelle's dysfunctions have been linked to disorders, including polycystic liver disease and cholangiocarcinoma. The goal of this study was to elucidate the relationship between primary cilia and the crucial regulator of cellular proliferation, the epidermal growth factor receptor (EGFR) signaling pathway, which has been associated with various clinical conditions.

APPROACH AND RESULTS

The study identified aberrant EGFR signaling pathways in cholangiocytes lacking functional primary cilia using liver-specific intraflagellar transport 88 knockout mice, a Pkhd1 mutant rat model, and human cell lines that did not have functional cilia. Cilia-deficient cholangiocytes showed persistent EGFR activation because of impaired receptor degradation, in contrast to their normal counterparts, where EGFR localization to the cilia promotes appropriate signaling. Using histone deacetylase 6 inhibitors to restore primary cilia accelerates EGFR degradation, thereby reducing maladaptive signaling. Importantly, experimental intervention with the histone deacetylase 6 inhibitor tubastatin A in an orthotopic rat model moved EGFR to cilia and reduced ERK phosphorylation. Concurrent administration of EGFR and histone deacetylase 6 inhibitors in cholangiocarcinoma and polycystic liver disease cells demonstrated synergistic antiproliferative effects, which were associated with the restoration of functioning primary cilia.

CONCLUSIONS

This study's findings shed light on ciliary function and robust EGFR signaling with slower receptor turnover. We could use therapies that restore the function of primary cilia to treat EGFR-driven diseases in polycystic liver disease and cholangiocarcinoma.

Anti-cancer potential of zerumbone in cancer and glioma: current trends and future perspectives

Plant-derived immunomodulators and antitumor factors have appealed lots of attention from natural product scientists for their efficiency and safety and their important contribution to well-designed targeted drug action and delivery mechanisms. Zerumbone (ZER), the chief component of Zingiber zerumbet rhizomes, has been examined for its wide-spectrum in the treatment of multi-targeted diseases. The rhizomes have been used as food flavoring agents in numerous cuisines and in flora medication. Numerous in vivo and in vitro experiments have prepared confirmation of ZER as a potent immunomodulator as well as a potential anti-tumor agent. This review is an interesting compilation of all the important results of the research carried out to date to investigate the immunomodulatory and anticancer properties of ZER. The ultimate goal of this comprehensive review is to supply updated information and a crucial evaluation on ZER, including its chemistry and immunomodulating and antitumour properties, which may be of principal importance to supply a novel pathway for subsequent investigation to discover new agents to treat cancers and immune-related sickness. In addition, updated information on the toxicology of ZER has been summarized to support its safety profile.

Primary Sclerosing Cholangitis Limited to Intrahepatic Bile Ducts Has Distinctly Better Prognosis

BACKGROUND

There are two sub-phenotypes of large-duct primary sclerosing cholangitis (PSC): isolated intrahepatic PSC (IIPSC) and extrahepatic disease with or without intrahepatic (extra/intrahepatic).

AIMS

This study examined the differences in outcomes in patients with IIPSC compared to extra/intrahepatic and small-duct PSC.

METHODS

Patients with PSC treated at our institution from 1998 to 2019 were investigated. Biochemistries, clinical events, and survival were assessed by chart review and National Death Index. Cox-proportional hazards were used to determine the risk of clinical outcomes based on biliary tract involvement.

RESULTS

Our cohort comprised 442 patients with large-duct PSC (57 had IIPSC, 385 had extra/intrahepatic PSC) and 23 with small-duct PSC. Median follow-up in the IIPSC group was not significantly different from the extra/intrahepatic group [7 vs. 6 years, P = 0.06]. Except for lower age (mean 37.9 vs. 43.0 years, P = 0.045), the IIPSC group was not different from the extra/intrahepatic. The IIPSC group had longer transplant-free survival (log-rank P = 0.001) with a significantly lower risk for liver transplantation (12% vs. 34%, P < 0.001). The IIPSC group had a lower risk of death or transplantation than the extra/intrahepatic PSC group [HR: 0.34, 95% CI: 0.17-0.67, P < 0.001]. No bile duct or gallbladder cancers developed in patients with IIPSC, compared to 24 in the extra/intrahepatic group. The clinical characteristics and outcomes of IIPSC were similar to 23 individuals with small-duct PSC.

CONCLUSIONS

Patients with IIPSC have a favorable prognosis similar to small-duct PSC. These data are important for counseling patients and designing therapeutic trials for PSC.

THBS1 and THBS2 Enhance the In Vitro Proliferation, Adhesion, Migration and Invasion of Intrahepatic Cholangiocarcinoma Cells

In intrahepatic cholangiocarcinoma (iCCA), thrombospondin 1 (THBS1) and 2 (THBS2) are soluble mediators released in the tumor microenvironment (TME) that contribute to the metastatic spreading of iCCA cells via a lymphatic network by the trans-differentiation of vascular endothelial cells to a lymphatic-like phenotype. To study the direct role of THBS1 and THBS2 on the iCCA cells, well-established epithelial (HuCCT-1) and mesenchymal (CCLP1) iCCA cell lines were subjected to recombinant human THBS1 and THBS2 (rhTHBS1, rhTHBS2) for cellular function assays. Cell growth, cell adhesion, migration, and invasion were all enhanced in both CCLP1 and HuCCT-1 cells by the treatment with either rhTHBS1 or rhTHBS2, although they showed some variability in their intensity of speeding up cellular processes. rhTHBS2 was more intense in inducing invasiveness and in committing the HuCCT-1 cells to a mesenchymal-like phenotype and was therefore a stronger enhancer of the malignant behavior of iCCA cells compared to rhTHBS1. Our data extend the role of THBS1 and THBS2, which are not only able to hinder the vascular network and promote tumor-associated lymphangiogenesis but also exacerbate the malignant behavior of the iCCA cells.

The expression of VEGF and cyclin D1/EGFR in common primary liver carcinomas in Egypt: an immunohistochemical study

Background

The most common types of primary malignant liver tumours are hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Treatment options for patients who are inoperable/advanced, or recurring are challenging. Cyclin D1, epidermal growth factor (EGFR) and vascular endothelial growth factor (VEGR) are common carcinogenic proteins that have potential therapeutic targets in various cancers. They have been implicated in the development of HCC and CCA. In this study, we aimed to evaluate the oncogenic function expression of cyclin D1, EGFR and VEGF in HCC and CCA of Egyptian patients. This could help to validate their therapeutic potential.

Material and methods

Tumour cases were selected from 82 cases of primary liver carcinomas, with 58 cases being from HCC and 24 cases from CCA compared to 51 non-tumour adjacent liver cases and 18 from normal liver tissue. The immunohistochemical study of cyclin D1, EGFR and VEGR was conducted.

Results

Cyclin D1, EGFR and VEGF are overexpressed in HCC and CCA as compared to the control group (p < 0.001). Cyclin D1 was related to well-differentiated grade and early pathologic stage in HCC (p = 0.016 and p = 0.042, respectively). The well-differentiated grade showed significantly higher VEGF levels (p = 0.04). In the CCA group, however, EGFR was strongly related to high tumour size (p = 0.047). EGFR and VEGF were overexpressed in HCC raised in the non-cirrhotic liver compared to those developed in post-hepatitic liver cirrhosis (p = 0.003 and p = 0.014).

Conclusion

Cyclin D1, EGFR and VEGF shared significant overexpression in HCC and CCA. EGFR and VEGF may play an oncogenic function in the development of HCC in non-cirrhotic liver. Furthermore, cyclin D1 and VEGF may play a good prognostic function in HCC, but EGFR may play a bad prognostic role in CCA.

Panic at the Bile Duct: How Intrahepatic Cholangiocytes Respond to Stress and Injury

In the liver, biliary epithelial cells (BECs) line intrahepatic bile ducts (IHBDs) and are primarily responsible for modifying and transporting hepatocyte-produced bile to the digestive tract. BECs comprise only 3% to 5% of the liver by cell number but are critical for maintaining choleresis through homeostasis and disease. To this end, BECs drive an extensive morphologic remodeling of the IHBD network termed ductular reaction (DR) in response to direct injury or injury to the hepatic parenchyma. BECs are also the target of a broad and heterogenous class of diseases termed cholangiopathies, which can present with phenotypes ranging from defective IHBD development in pediatric patients to progressive periductal fibrosis and cancer. DR is observed in many cholangiopathies, highlighting overlapping similarities between cell- and tissue-level responses by BECs across a spectrum of injury and disease. The following core set of cell biological BEC responses to stress and injury may moderate, initiate, or exacerbate liver pathophysiology in a context-dependent manner: cell death, proliferation, transdifferentiation, senescence, and acquisition of neuroendocrine phenotype. By reviewing how IHBDs respond to stress, this review seeks to highlight fundamental processes with potentially adaptive or maladaptive consequences. A deeper understanding of how these common responses contribute to DR and cholangiopathies may identify novel therapeutic targets in liver disease.

Advanced endoscopy meets molecular diagnosis of cholangiocarcinoma

Cholangiocarcinoma remains an aggressive and deadly malignancy that is often diagnosed late. Intrinsic tumour characteristics and the growth pattern of cancer cells contribute to the challenges of diagnosis and chemoresistance. However, establishing an early and accurate diagnosis, and in some instances identifying targetable changes, has the potential to impact survival. Primary sclerosing cholangitis, a chronic cholangiopathy prodromal to the development of a minority of cholangiocarcinomas, poses a particular diagnostic challenge. We present our diagnostic and theranostic approach to the initial evaluation of cholangiocarcinomas, focusing on extrahepatic cholangiocarcinoma. This involves a multipronged strategy incorporating advanced imaging, endoscopic methods, multiple approaches to tissue sampling, and molecular markers. We also provide an algorithm for the sequential use of these tools.

YTHDF1 promotes intrahepatic cholangiocarcinoma progression via regulating EGFR mRNA translation

BACKGROUND AND AIM

Intrahepatic cholangiocarcinoma (ICC) is a highly aggressive disease with the underlying mechanisms poorly understood. YTHDF1, an N⁶ -methyladenosine (m⁶ A) reader protein, has important physiological functions in regulation of tumor development. However, the effect of YTHDF1 on ICC progression remains unknown yet.

METHODS

The expression level of YTHDF1 in human ICC tissue was examined in The Cancer Genome Atlas database and our cohort. The role of YTHDF1 was detected using two human ICC cell lines in vitro. An ICC tumorigenesis mouse model was established via hydrodynamic transfection of AKT/YAP plasmids. m⁶ A sequencing, RNA immunoprecipitation sequencing, and RNA sequencing were carried out to explore the mechanism of YTHDF1 modulating ICC progression.

RESULTS

Here, we find that YTHDF1 is upregulated in ICC and associated with shorter survival of ICC patients. Depletion of YTHDF1 inhibits cell proliferation, migration, and invasion, while overexpression of wild-type YTHDF1, but not m⁶ A reader domain mutant YTHDF1, significantly enhances tumor cell growth and aggressive abilities in vitro. Moreover, overexpression of YTHDF1 promotes the AKT/YAP transfection-induced orthotopic ICC tumorigenesis and progression in vivo. Mechanistically, we identify that YTHDF1 regulates the translation of epidermal growth factor receptor (EGFR) mRNA via binding m⁶ A sites in the 3'-UTR of EGFR transcript, thus leading to aberrant activities of downstream signal pathways that impact tumor progression.

CONCLUSIONS

Our data uncover the oncogenic function and m⁶ A reader-dependent mechanism of YTHDF1 in regulation of ICC progression. Restricting abnormal oncogenic mRNA translation by targeting YTHDF1 may be a novel and promising strategy for ICC treatment.

Inflammatory pathways and cholangiocarcinoma risk mechanisms and prevention

Cholangiocarcinoma (CCA), a neoplasm burdened by a poor prognosis and currently lacking adequate therapeutic treatments, can originate at different levels of the biliary tree, in the intrahepatic, hilar, or extrahepatic area. The main risk factors for the development of CCA are the presence of chronic cholangiopathies of various etiology. To date, the most studied prodromal diseases of CCA are primary sclerosing cholangitis, Caroli's disease and fluke infestations, but other conditions, such as metabolic syndrome, nonalcoholic fatty liver disease and obesity, are emerging as associated with an increased risk of CCA development. In this review, we focused on the analysis of the pro-inflammatory mechanisms that induce the development of CCA and on the role of cells of the immune response in cholangiocarcinogenesis. In very recent times, these cellular mechanisms have been the subject of emerging studies aimed at verifying how the modulation of the inflammatory and immunological responses can have a therapeutic significance and how these can be used as therapeutic targets.

Multicenter randomized phase II trial of atezolizumab with or without cobimetinib in biliary tract cancers

BACKGROUNDMEK inhibitors have limited activity in biliary tract cancers (BTCs) as monotherapy but are hypothesized to enhance responses to programmed death ligand 1 (PD-L1) inhibition.METHODSThis open-label phase II study randomized patients with BTC to atezolizumab (anti-PD-L1) as monotherapy or in combination with cobimetinib (MEK inhibitor). Eligible patients had unresectable BTC with 1 to 2 lines of prior therapy in the metastatic setting, measurable disease, and Eastern Cooperative Oncology Group (ECOG) performance status less than or equal to 1. The primary endpoint was progression-free survival (PFS).RESULTSSeventy-seven patients were randomized and received study therapy. The trial met its primary endpoint, with a median PFS of 3.65 months in the combination arm versus 1.87 months in the monotherapy arm (HR 0.58, 90% CI 0.35-0.93, 1-tail P = 0.027). One patient in the combination arm (3.3%) and 1 patient in the monotherapy arm (2.8%) had a partial response. Combination therapy was associated with more rash, gastrointestinal events, CPK elevations, and thrombocytopenia. Exploratory analysis of tumor biopsies revealed enhanced expression of antigen processing and presentation genes and an increase in CD8/FoxP3 ratios with combination treatment. Patients with higher baseline or lower fold changes in expression of certain inhibitory ligands (LAG3, BTLA, VISTA) on circulating T cells had evidence of greater clinical benefit from the combination.CONCLUSIONThe combination of atezolizumab plus cobimetinib prolonged PFS as compared with atezolizumab monotherapy, but the low response rate in both arms highlights the immune-resistant nature of BTCs.TRIAL REGISTRATIONClinicalTrials.gov NCT03201458.FUNDINGNational Cancer Institute (NCI) Experimental Therapeutics Clinical Trials Network (ETCTN); F. Hoffmann-La Roche, Ltd.; NCI, NIH (R01 CA228414-01 and UM1CA186691); NCI's Specialized Program of Research Excellence (SPORE) in Gastrointestinal Cancers (P50 CA062924); NIH Center Core Grant (P30 CA006973); and the Passano Foundation.

Extracellular Signal-Regulated Kinase 5 Regulates the Malignant Phenotype of Cholangiocarcinoma Cells

BACKGROUND AND AIMS

Cholangiocarcinoma (CCA) is characterized by high resistance to chemotherapy and poor prognosis. Several oncogenic pathways converge on activation of extracellular signal-regulated kinase 5 (ERK5), whose role in CCA has not been explored. The aim of this study was to investigate the role of ERK5 in the biology of CCA.

APPROACH AND RESULTS

ERK5 expression was detected in two established (HuCCT-1 and CCLP-1) and two primary human intrahepatic CCA cell lines (iCCA58 and iCCA60). ERK5 phosphorylation was increased in CCA cells exposed to soluble mediators. In both HuCCT-1 and CCLP-1 cells, ERK5 was localized in the nucleus, and exposure to fetal bovine serum (FBS) further increased the amount of nuclear ERK5. In human CCA specimens, ERK5 mRNA expression was increased in tumor cells and positively correlated with portal invasion. ERK5 protein levels were significantly associated with tumor grade. Growth, migration, and invasion of CCA cells were decreased when ERK5 was silenced using specific short hairpin RNA (shRNA). The inhibitory effects on CCA cell proliferation, migration and invasion were recapitulated by treatment with small molecule inhibitors targeting ERK5. In addition, expression of the angiogenic factors VEGF and angiopoietin 1 was reduced after ERK5 silencing. Conditioned medium from ERK5-silenced cells had a lower ability to induce tube formation by human umbilical vein endothelial cells and to induce migration of myofibroblasts and monocytes/macrophages. In mice, subcutaneous injection of CCLP-1 cells silenced for ERK5 resulted in less frequent tumor development and smaller size of xenografts compared with cells transfected with nontargeting shRNA.

CONCLUSIONS

ERK5 is a key mediator of growth and migration of CCA cells and supports a protumorigenic crosstalk between the tumor and the microenvironment.

Probing the Anti-Cancer Potency of Sulfated Galactans on Cholangiocarcinoma Cells Using Synchrotron FTIR Microspectroscopy, Molecular Docking, and In Vitro Studies

Sulfated galactans (SG) isolated from red alga Gracilaria fisheri have been reported to inhibit the growth of cholangiocarcinoma (CCA) cells, which was similar to the epidermal growth factor receptor (EGFR)-targeted drug, cetuximab. Herein, we studied the anti-cancer potency of SG compared to cetuximab. Biological studies demonstrated SG and cetuximab had similar inhibition mechanisms in CCA cells by down-regulating EGFR/ERK pathway, and the combined treatment induced a greater inhibition effect. The molecular docking study revealed that SG binds to the dimerization domain of EGFR, and this was confirmed by dimerization assay, which showed that SG inhibited ligand-induced EGFR dimer formation. Synchrotron FTIR microspectroscopy was employed to examine alterations in cellular macromolecules after drug treatment. The SR-FTIR-MS elicited similar spectral signatures of SG and cetuximab, pointing towards the bands of RNA/DNA, lipids, and amide I vibrations, which were inconsistent with the changes of signaling proteins in CCA cells after drug treatment. Thus, this study demonstrates the underlined anti-cancer mechanism of SG by interfering with EGFR dimerization. In addition, we reveal that FTIR signature spectra offer a useful tool for screening anti-cancer drugs’ effect.

The Effect of the EGFR - Targeting Compound 3-[(4-Phenylpyrimidin-2-yl) Amino] Benzene-1-Sulfonamide (13f) against Cholangiocarcinoma Cell Lines

OBJECTIVE

Cholangiocarcinoma (CCA) is a noxious malignancy of epithelium of the bile duct with a low response rate to chemotherapy. The epidermal growth factor receptor (EGFR) signaling pathway is implicated in the development of cancerous cells, especially CCA. In this study, we report detailed biological profiling of 13f identified from our earlier hit expansion studies. The aim of this work was to expand our understanding of 13f via more detailed investigations of its mechanism of action against KKU-100, KKU-452 and KKU-M156 CCA cells, as well as in comparison to the EGFR inhibitor Gefitinib and non-specific chemotherapeutic agents such as Cisplatin.

METHODS

Inhibiting EGFR-Kinase, cytotoxicity, clonogenic assay, wound healing and apoptosis were performed. Levels of total expression of EGFR and EGFR phosphorylation proteins were detected.

RESULTS

13f was confirmed as an inhibitor of EGFR with an IC50 value against the tyrosine kinase of EGFR of 22 nM and IC50 values for 48 h incubation period were 1.3 ± 1.9, 1.5 ± 0.4 and 1.7 ± 1.1 µM of KKU-100, KKU-452 and KKU-M156, respectively through dose- and time-dependent induction of early apoptosis of CCA cells. The compound also suppressed the clonogenic ability of KKU-100 and KKU-M156 cells stronger than Gefitinib, while potently inhibiting EGF-stimulated CCA cell migratory activity in KKU-452 cells. It was observed that under normal conditions EGFR was activated in CCA cells. EGF-stimulated basal expression of EGFR in KKU-452 cells was suppressed following 13f treatment, which was significantly greater than that of the marketed EGFR inhibitor Gefitinib.

CONCLUSION

In summary, our study showed that 13f has potent anti-cancer activities including antiproliferation, clonogenic ability and migration through the modulation of EGFR signaling pathway in CCA for the first time. The compound represents an interesting starting point as a potential chemotherapeutic agent in ongoing efforts to improve response rate in CCA patients.<br />.

A novel synthetic acanthoic acid analogues and their cytotoxic activity in cholangiocarcinoma cells

A novel series of acanthoic acid analogues containing triazole moiety were synthesized through esterification and CuAAC reaction. Evaluation of their biological activities against four cell lines of cholangiocarcinoma cells showed that 3d exhibited the strongest activity with an IC₅₀ value of 18 µM against KKU-213 cell line, which was 8 fold more potent than acanthoic acid. Interestingly, the triazole ring and nitro group on benzyl ring play very significant role in cytotoxic activity. The computational studies revealed that 3d occupies the binding energy of -12.7 and -10.8 kcal/mol with CDK-2 and EGFR protein kinases, respectively. This result might provide a beginning for the development of acanthoic acid analogues as an anticancer agent.

An assessment of chromosomal alterations detected by fluorescence in situ hybridisation in pancreatobiliary tract malignancy

Background

Using fluorescence in situ hybridisation (FISH) to detect any gain of chromosomes 3, 7, or 17 and loss of the 9p21 locus has been proven to be sensitive in the diagnosis of pancreatobiliary tumors. However, both genetic and environmental factors contribute to the pathogenesis of pancreatobiliary tumors. Therefore, it is unknown whether this method is suitable for Chinese patients with pancreatobiliary tumors. This study aims to compare the sensitivity, specificity, predictive values and accuracy of cytology, ERCP/MRCP and FISH based on Chinese patients with pancreatobiliary tumors,and to analyze differences between brushing-based and formalin-fixed paraffin-embedded (FFPE)-based FISH.

Methods

A total of 66 brush cytology specimens obtained during ERCP were detected by FISH and cytology test respectively to compare the sensitivity, specificity, predictive values and accuracy. Besides, FFPE-based FISH was performed on 46 corresponding paraffin sections of pancreatobiliary tumors obtained by surgical resection.

Results

Our findings demonstrate that FISH greatly improves diagnostic sensitivity and negative predictive value compared to ERCP/MRCP and cytology without much reduction in specificity and positive predictive value. However, our results also indicate that FFPE-based FISH could not effectively identify the false-negative of brushing-based FISH.

Conclusions

We believe that FISH can effectively distinguish true positive and false positive results of cytological or radiological suspicions of malignancy. However, FFPE-based FISH still does not precisely recognize the false-negative of brushing-based FISH. Both cytology-based and PPFE-based FISH had limitation in some specimens.

ErBb Family Proteins in Cholangiocarcinoma and Clinical Implications

The erythroblastic leukemia viral oncogene homolog (ErBb) family consists of the receptor tyrosine kinases (RTK) epidermal growth factor receptor (EGFR; also called ERBB1), ERBB2, ERBB3, and ERBB4. This family is closely associated with the progression of cholangiocarcinoma (CC) through the regulation of cellular networks, which are enhanced during tumorigenesis, metastasis, and chemoresistance. Additionally, the constitutive activation of cellular signaling by the overexpression and somatic mutation-mediated alterations conferred by the ErBb family on cholangiocarcinoma and other cancers enhances tumor aggressiveness and chemoresistance by contributing to the tumor microenvironment. This review summarizes the recent findings on the molecular functions of the ErBb family and their mutations during the progression of cholangiocarcinoma. It also discusses the developments and applications of various devising strategies for targeting the ErBb family through different inhibitors in various stages of clinical trials, which are essential for improving targeted clinical therapies.

TESC Promotes TGF-α/EGFR-FOXM1-Mediated Tumor Progression in Cholangiocarcinoma

Cholangiocarcinoma is a relatively uncommon but highly lethal malignancy. Improving outcomes in patients depends on earlier diagnosis and appropriate treatment; however, no satisfactory diagnostic biomarkers or targeted therapies are currently available. To address this shortcoming, we analyzed the transcriptomic datasets of cholangiocarcinoma from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and found that TESC is highly expressed in cholangiocarcinoma. Elevated cellular levels of TESC are correlated with larger tumor size and predict a poor survival outcome for patients. Knockdown of TESC via RNA interference suppresses tumor growth. RNA-sequencing analysis showed that silencing of TESC decreases the level of FOXM1, leading to cell cycle arrest. Correlation analysis revealed that the cellular level of TESC is correlated with that of FOXM1 in cholangiocarcinoma patients. We further observed that upon TGF-α induction, TESC is upregulated through the EGFR-STAT3 pathway and mediates TGF-α-induced tumor cell proliferation. In vivo experiments revealed that knockdown of TESC significantly attenuates tumor cell growth. Therefore, our data provide novel insight into TESC-mediated oncogenesis and reveal that TESC is a potential biomarker or serves as a therapeutic target for cholangiocarcinoma.

Anticancer Effect of Radix Astragali on Cholangiocarcinoma In Vitro and Its Mechanism via Network Pharmacology

Background

This study used network pharmacology method and cell model to assess the effects of Radix Astragali (RA) on cholangiocarcinoma (CCA) and to predict core targets and molecular mechanisms.

Material/Methods

We performed an in vitro study to assess the effect of RA on CCA using CCK8 assay, the Live-Cell Analysis System, and trypan blue staining. The components and targets of RA were analyzed using the Traditional Chinese Medicine Systems Pharmacology database, and genes associated with CCA were retrieved from the GeneCards and OMIM platforms. Protein–protein interactions were analyzed with the STRING platform. The components–targets–disease network was built by Cytoscape. The TIMER database revealed the expression of core targets with diverse immune infiltration levels. GO and KEGG analyses were performed to identify molecular-biology processes and signaling pathways. The predictions were verified by Western blotting.

Results

Concentration-dependent antitumor activity was confirmed in the cholangiocarcinoma QBC939 cell line treated with RA. RA contained 16 active compounds, with quercetin and kaempferol as the core compounds. The most important biotargets for RA in CCA were caspase 3, MAPK8, MYC, EGFR, and PARP. The TIMER database revealed that the expression of caspase3 and MYC was related with diverse immune infiltration levels of CCA. The results of Western blotting showed RA significantly influenced the expression of the 5 targets that network pharmacology predicted.

Conclusions

RA is an active medicinal material that can be developed into a safe and effective multi-targeted anticancer treatment for CCA.

Terminal fucose mediates progression of human cholangiocarcinoma through EGF/EGFR activation and the Akt/Erk signaling pathway

Aberrant glycosylation is recognized as a cancer hallmark that is associated with cancer development and progression. In this study, the clinical relevance and significance of terminal fucose (TFG), by fucosyltransferase-1 (FUT1) in carcinogenesis and progression of cholangiocarcinoma (CCA) were demonstrated. TFG expression in human and hamster CCA tissues were determined using Ulex europaeus agglutinin-I (UEA-I) histochemistry. Normal bile ducts rarely expressed TFG while 47% of CCA human tissues had high TFG expression and was correlated with shorter survival of patients. In the CCA-hamster model, TFG was elevated in hyperproliferative bile ducts and gradually increased until CCA was developed. This evidence indicates the involvement of TFG in carcinogenesis and progression of CCA. The mechanistic insight was performed in 2 CCA cell lines. Suppression of TFG expression using siFUT1 or neutralizing the surface TFG with UEA-I significantly reduced migration, invasion and adhesion of CCA cells in correlation with the reduction of Akt/Erk signaling and epithelial-mesenchymal transition. A short pulse of EGF could stimulate Akt/Erk signaling via activation of EGF-EGFR cascade, however, decreasing TFG using siFUT1 or UEA-I treatment reduced the EGF-EGFR activation and Akt/Erk signaling. This evidence provides important insight into the relevant role and molecular mechanism of TFG in progression of CCA.

Effects of aspirin and non-steroidal anti-inflammatory drugs on the risk of cholangiocarcinoma: a meta-analysis

BACKGROUND

Non-steroidal anti-inflammatory drugs (NSAIDs) can suppress the proliferation of cholangiocarcinoma (CCA) cells in vitro through inhibition of cyclooxygenase-2. However, the effects of aspirin and NSAIDs on the risk of CCA remain unclear. We performed this meta-analysis to assess the risk of biliary tract cancers in patients who take aspirin and/or NSAIDs.

METHODS

A systematic review was conducted utilizing MEDLINE, EMBASE, Cochrane databases from inception through October 2017 to identify studies that assessed the association of aspirin and/or NSAIDs use with risk of biliary tract cancers including CCA, gallbladder cancer and ampulla of Vater cancer. Effect estimates from the studies were extracted and combined using the random-effect, generic inverse variance method of DerSimonian and Laird.

RESULTS

Five observational studies with a total of 9 200 653 patients were enrolled. The pooled OR of CCA in patients with aspirin use was 0.56 (95% CI, 0.32-0.96). Egger's regression asymmetry test was performed and showed no publication bias for the association between aspirin use and CCA with P = 0.42. There was no significant association between NSAIDs use and CCA, with a pooled OR of 0.79 (95% CI, 0.28-2.21). One study showed a significant association between aspirin use and reduced risk of gallbladder cancer with OR of 0.37 (0.17-0.80). However, there was no significant association between aspirin and ampulla of Vater cancer with OR of 0.22 (0.03-1.65).

CONCLUSIONS

Our study demonstrates a significant association between aspirin use and a 0.56-fold decreased risk of CCA. However, there is no association between the use of NSAIDs and CCA.

Signalling networks in cholangiocarcinoma: Molecular pathogenesis, targeted therapies and drug resistance

Cholangiocarcinoma (CCA) is a deadly disease. While surgery may attain cure in a minor fraction of cases, therapeutic options in either the adjuvant or advanced setting are limited. The possibility of advancing the efficacy of therapeutic approaches to CCA relies on understanding its molecular pathogenesis and developing rational therapies aimed at interfering with oncogenic signalling networks that drive and sustain cholangiocarcinogenesis. These efforts are complicated by the intricate biology of CCA, which integrates not only the driving force of tumour cell-intrinsic alterations at the genetic and epigenetic level but also pro-tumorigenic cues conveyed to CCA cells by different cell types present in the rich tumour stroma. Herein, we review our current understanding of the mechanistic bases underpinning the activation of major oncogenic pathways causative of CCA pathogenesis. We subsequently discuss how this knowledge is being exploited to implement rationale-based and genotype-matched therapeutic approaches that predictably will radically transform CCA clinical management in the next decade. We conclude by highlighting the mechanisms of therapeutic resistance in CCA and reviewing innovative approaches to combat resistance at the preclinical and clinical level.

Fibroinflammatory Liver Injuries as Preneoplastic Condition in Cholangiopathies

The cholangipathies are a class of liver diseases that specifically affects the biliary tree. These pathologies may have different etiologies (genetic, autoimmune, viral, or toxic) but all of them are characterized by a stark inflammatory infiltrate, increasing overtime, accompanied by an excess of periportal fibrosis. The cellular types that mount the regenerative/reparative hepatic response to the damage belong to different lineages, including cholagiocytes, mesenchymal and inflammatory cells, which dynamically interact with each other, exchanging different signals acting in autocrine and paracrine fashion. Those messengers may be proinflammatory cytokines and profibrotic chemokines (IL-1, and 6; CXCL1, 10 and 12, or MCP-1), morphogens (Notch, Hedgehog, and WNT/β-catenin signal pathways) and finally growth factors (VEGF, PDGF, and TGFβ, among others). In this review we will focus on the main molecular mechanisms mediating the establishment of a fibroinflammatory liver response that, if perpetuated, can lead not only to organ dysfunction but also to neoplastic transformation. Primary Sclerosing Cholangitis and Congenital Hepatic Fibrosis/Caroli’s disease, two chronic cholangiopathies, known to be prodrome of cholangiocarcinoma, for which several murine models are also available, were also used to further dissect the mechanisms of fibroinflammation leading to tumor development.

Genistein reduces the activation of AKT and EGFR, and the production of IL6 in cholangiocarcinoma cells involving estrogen and estrogen receptors

Cholangiocarcinoma (CCA) is a malignant tumor of the biliary epithelium associated with Opisthorchis viverrini, primary sclerosing cholangitis and hepatitis viral infection. In the global population, men have higher incidence rates for CCA than women; thus, a gender disparity in the progression of chronic inflammation of the biliary duct leading to malignancy may involve the effects of estrogen (E2). Genistein (GE), a prominent phytoestrogen found in soy products, is an estrogen receptor β (ERβ) agonist and a tyrosine kinase inhibitor. The present study investigated the effects of GE on the growth of CCA cells by cell viability assay. The effects on signaling proteins were detected by western blot analysis and ELISA. Gene expression was examined by RT-qPCR. Two human intrahepatic CCA cell lines, HuCCA‑1 and RMCCA‑1, were utilized. GE (50‑200 µM) reduced the viability of the two cell lines, and also inhibited the activation of epidermal growth factor receptor (EGFR) and AKT, as evidenced by decreasing protein levels of phosphorylated (p)-EGFR (Tyr1173) and p‑AKT (Ser473), respectively. GE altered the mitogen‑activated protein kinase signaling cascade by mediating decreased protein levels of p‑p38 and increased protein levels of p‑ERK1/2. GE significantly decreased the levels of interleukin 6 (IL6) and induced the expression of inducible nitric oxide synthase (iNOS). GE also downregulated the expression of p‑ERα (Ser118) protein and ERα mRNA levels. Finally, GE induced the downregulation of the protein levels of ERβ. Of note, E2 deprivation potentiated the GE-induced reduction of p‑EGFR (Tyr1173) and total AKT proteins and production of IL6, and mediated the downregulation of GE-induced iNOS protein. In conclusion, GE inhibited the growth of human CCA cell lines by reducing the activation of EGFR and AKT, and by attenuating the production of IL6. E2 and ER were also involved in the growth-inhibitory effect of GE in CCA cells.

Molecular Mechanisms Driving Cholangiocarcinoma Invasiveness: An Overview

The acquisition of invasive functions by tumor cells is a first and crucial step toward the development of metastasis, which nowadays represents the main cause of cancer-related death. Cholangiocarcinoma (CCA), a primary liver cancer originating from the biliary epithelium, typically develops intrahepatic or lymph node metastases at early stages, thus preventing the majority of patients from undergoing curative treatments, consistent with their very poor prognosis. As in most carcinomas, CCA cells gradually adopt a motile, mesenchymal-like phenotype, enabling them to cross the basement membrane, detach from the primary tumor, and invade the surrounding stroma. Unfortunately, little is known about the molecular mechanisms that synergistically orchestrate this proinvasive phenotypic switch. Autocrine and paracrine signals (cyto/chemokines, growth factors, and morphogens) permeating the tumor microenvironment undoubtedly play a prominent role in this context. Moreover, a number of recently identified signaling systems are currently drawing attention as putative mechanistic determinants of CCA cell invasion. They encompass transcription factors, protein kinases and phosphatases, ubiquitin ligases, adaptor proteins, and miRNAs, whose aberrant expression may result from either stochastic mutations or the abnormal activation of upstream pro-oncogenic pathways. Herein we sought to summarize the most relevant molecules in this field and to discuss their mechanism of action and potential prognostic relevance in CCA. Hopefully, a deeper knowledge of the molecular determinants of CCA invasiveness will help to identify clinically useful biomarkers and novel druggable targets, with the ultimate goal to develop innovative approaches to the management of this devastating malignancy.

Role of ErbB/HER family of receptor tyrosine kinases in cholangiocyte biology

The ErbB/HER family comprises four distinct tyrosine kinase receptors, EGFR/ErbB1/HER1, ErbB2/HER2, ErbB3/HER3, and ErbB4/HER4, which trigger intracellular signals at the origin of essential cellular functions, including differentiation, proliferation, survival, and migration. Epithelial cells, named cholangiocytes, that line intrahepatic and extrahepatic bile ducts, contribute substantially to biliary secretory functions and bile transport. Although ErbB receptors have been widely studied in cholangiocarcinoma (CCA), a malignancy of the biliary tract, knowledge of these receptors in biliary epithelium physiology and in non-malignant cholangiopathies is far from complete. Current knowledge suggests a role for epidermal growth factor receptor (EGFR) in cholangiocyte specification and proliferation, and in hepatocyte transdifferentiation into cholangiocytes during liver regeneration to restore biliary epithelium integrity. High expression and activation of EGFR and/or ErbB2 were recently demonstrated in biliary lithiasis and primary sclerosing cholangitis, two cholangiopathies regarded as risk factors for CCA. In CCA, ErbB receptors are frequently overexpressed, leading to tumor progression and low prognosis. Anti-ErbB therapies were efficient only in preclinical trials and have suggested the existence of resistance mechanisms with the need to identify predictive factors of therapy response. This review aims to compile the current knowledge on the functions of ErbB receptors in physiology and physiopathology of the biliary epithelium. (Hepatology 2018;67:762-773).

Prognostic and predictive role of EGFR pathway alterations in biliary cancer patients treated with chemotherapy and anti-EGFR

The association of anti-EGFR to gemcitabine and oxaliplatin (GEMOX) chemotherapy did not improve survival in biliary tract carcinoma (BTC) patients. Multiple mechanisms might be involved in the resistance to anti-EGFR. Here, we explored the mutation profile of EGFR extracellular domain (ECD), of tyrosine kinase domain (TKD), and its amplification status. EGFR mutational status of exons 12, 18–21 was analyzed in 57 tumors by Sanger sequencing. EGFR amplification was evaluated in 37 tumors by Fluorescent In Situ Hybridization (FISH). Kaplan-Meier curves were calculated using the log-rank test. Six patients had mutations in exon 12 of EGFR ECD and 7 in EGFR TKD. Neither EGFR ECD nor TKD mutations affected progression free survival (PFS) or overall survival (OS) in the entire population. In the panitumumab plus GEMOX (P-GEMOX) arm, ECD mutated patients had a worse OS, while EGFR TKD mutated patients had a trend towards shorter PFS and OS. Overall, the presence of mutations in EGFR or in its transducers did not affect PFS or OS, while the extrahepatic cholangiocarcinoma (ECC) mutated patients had a worse prognosis compared to WT. Nineteen out of 37 tumors were EGFR amplified, but the amplification did not correlate with survival. ECC EGFR amplified patients had improved OS, whereas the amplification significantly correlated with poor PFS (p = 0.03) in gallbladder carcinoma patients. The high molecular heterogeneity is a predominant feature of BTC: the alterations found in this work seem to have a prognostic impact rather than a predictive role towards anti-EGFR therapy.

Intrahepatic cholangiocarcinoma: Role of metabolism in pathogenesis, clinical diagnosis, and treatment

Recent studies demonstrated that metabolism plays an important role in the pathogenesis, clinical diagnosis, and treatment of intrahepatic cholangiocarcinoma (ICC). The mechanisms of several metabolic enzymes associated with ICC, including pyruvate kinase M2 (PKM2), thymidine synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), isocitric acid dehydrogenase 1/2 (IDH1/2), and cyclo-oxygenase-2 (COX-2), have been gradually clarified and hopefully transformed into clinical application in the future. Besides, ICC patients always have concomitant abnormal lipid metabolism, which has attracted the attention of clinicians and researchers. Metabolites in serum and bile have potential diagnostic utility, which has yet to be verified by prospective clinical research. ¹⁸F-FDG PET/CT based on metabolism presents application value in many aspects of ICC, such as diagnosis, staging, evaluation of therapeutic effect, and monitoring prognosis. In this article, we review the recent progress in the understanding of the role of metabolism in ICC from both basic and clinical perspectives, with an aim to highlight the further research directions and accelerate the clinical transformation.

Cholangiocytes in the pathogenesis of primary sclerosing cholangitis and development of cholangiocarcinoma

Primary sclerosing cholangitis (PSC) is an idiopathic cholangiopathy strongly associated with inflammatory bowel disease (IBD) and characterized by cholestasis, chronic immune infiltration and progressive fibrosis of the intrahepatic and extrahepatic bile ducts. PSC confers a high risk of cholangiocarcinoma (CCA) with PSC-CCA representing the leading cause of PSC-associated mortality. PSC-CCA is derived from cholangiocytes and associated progenitor cells - a heterogeneous group of dynamic epithelial cells lining the biliary tree that modulate the composition and volume of bile production by the liver. Infection, inflammation and cholestasis can trigger cholangiocyte activation leading to an increased expression of adhesion and antigen-presenting molecules as well as the release of various inflammatory and fibrogenic mediators. As a result, activated cholangiocytes engage in a myriad of cellular processes, including hepatocellular proliferation, apoptosis, angiogenesis and fibrosis. Cholangiocytes can also regulate the recruitment of immune cells, mesenchymal cells, and endothelial cells that participate in tissue repair and destruction in settings of persistent inflammation. In PSC, the role of cholangiocytes and the mechanisms governing their transformation to PSC-CCA are unclear however localization of disease suggests that cholangiocytes are a key target and potential regulator of hepatobiliary immunity, fibrogenesis and tumorigenesis. Herein, we summarize mechanisms of cholangiocyte activation in PSC and highlight new insights into disease pathways that may contribute to the development of PSC-CCA. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Arctigenin induced gallbladder cancer senescence through modulating epidermal growth factor receptor pathway

Gallbladder cancer has poor prognosis and limited therapeutic options. Arctigenin, a representative dibenzylbutyrolactone lignan, occurs in a variety of plants. However, the molecular mechanisms involved in the antitumor effect of arctigenin on gallbladder cancer have not been fully elucidated. The expression levels of epidermal growth factor receptor were examined in 100 matched pairs of gallbladder cancer tissues. A positive correlation between high epidermal growth factor receptor expression levels and poor prognosis was observed in gallbladder cancer tissues. Pharmacological inhibition or inhibition via RNA interference of epidermal growth factor receptor induced cellular senescence in gallbladder cancer cells. The antitumor effect of arctigenin on gallbladder cancer cells was primarily achieved by inducing cellular senescence. In gallbladder cancer cells treated with arctigenin, the expression level of epidermal growth factor receptor significantly decreased. The analysis of the activity of the kinases downstream of epidermal growth factor receptor revealed that the RAF-MEK-ERK signaling pathway was significantly inhibited. Furthermore, the cellular senescence induced by arctigenin could be reverted by pcDNA-epidermal growth factor receptor. Arctigenin also potently inhibited the growth of tumor xenografts, which was accompanied by the downregulation of epidermal growth factor receptor and induction of senescence. This study demonstrates arctigenin could induce cellular senescence in gallbladder cancer through the modulation of epidermal growth factor receptor pathway. These data identify epidermal growth factor receptor as a key regulator in arctigenin-induced gallbladder cancer senescence.

The oral VEGF receptor tyrosine kinase inhibitor pazopanib in combination with the MEK inhibitor trametinib in advanced cholangiocarcinoma

Background:

Cholangiocarcinoma is an aggressive malignancy with limited therapeutic options. MEK inhibition and antiangiogenic therapies have individually shown modest activity in advanced cholangiocarcinoma, whereas dual inhibition of these pathways has not been previously evaluated. We evaluated the safety and efficacy of combination therapy with the oral VEGF receptor tyrosine kinase inhibitor pazopanib plus the MEK inhibitor trametinib in patients with advanced cholangiocarcinoma.

Methods:

In this open-label, multicentre, single-arm trial, adults with advanced unresectable cholangiocarcinoma received pazopanib 800 mg daily and trametinib 2 mg daily until disease progression or unacceptable toxicity. The primary end point was progression-free survival (PFS) with secondary end points including overall survival (OS), response rate, and disease control rate (DCR).

Results:

A total of 25 patients were enrolled and had received a median of 2 prior systemic therapies (range 1–7). Median PFS was 3.6 months (95% CI: 2.7–5.1) and the 4-month PFS was 40% (95% CI: 24.7–64.6%). There was a trend towards increased 4-month PFS as compared with the prespecified null hypothesised 4-month PFS of 25%, but this difference did not reach statistical significance (P=0.063). The median survival was 6.4 months (95% CI: 4.3–10.2). The objective response rate was 5% (95% CI: 0.13–24.9%) and the DCR was 75% (95% CI: 51%, 91%). Grade 3/4 adverse events attributable to study drugs were observed in 14 (56%) and included thrombocytopenia, abnormal liver enzymes, rash, and hypertension.

Conclusions:

Although the combination of pazopanib plus trametinib had acceptable toxicity with evidence of clinical activity, it did not achieve a statistically significant improvement in 4-month PFS over the prespecified null hypothesised 4-month PFS.

Sulfated Galactans from Red Seaweed Gracilaria fisheri Target EGFR and Inhibit Cholangiocarcinoma Cell Proliferation

Cholangiocarcinoma (CCA) is increasing in incidence worldwide and is resistant to chemotherapeutic agents, making treatment of CCA a major challenge. Previous studies reported that natural sulfated polysaccharides (SPs) disrupted growth factor receptor activation in cancer cells. The present study, therefore, aimed at investigating the antiproliferation effect of sulfated galactans (SG) isolated from the red seaweed Gracilaria fisheri (G. fisheri) on CCA cell lines. Direct binding activity of SG to CCA cells, epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) were determined. The effect of SG on proliferation of CCA cells was investigated. Cell cycle analyses and expression of signaling molecules associated with proliferation were also determined. The results demonstrated that SG bound directly to EGFR. SG inhibited proliferation of various CCA cell lines by inhibiting EGFR and extracellular signal-regulated kinases (ERK) phosphorylation, and inhibited EGF-induced increased cell proliferation. Cell cycle analyses showed that SG induced cell cycle arrest at the G0/G1 phase, down-regulated cell cycle genes and proteins (cyclin-D, cyclin-E, cdk-4, cdk-2), and up-regulated the tumor suppressor protein P53 and the cyclin-dependent kinase inhibitor P21. Taken together, these data demonstrate that SG from G. fisheri inhibited proliferation of CCA cells, and its mechanism of inhibition is mediated, to some extent, by inhibitory effects on EGFR activation and EGFR/ERK signaling pathway. SG presents a potential EGFR targeted molecule, which may be further clinically developed in a combination therapy for CCA treatment.

Biliary cancer: intrahepatic cholangiocarcinoma vs. extrahepatic cholangiocarcinoma vs. gallbladder cancers: classification and therapeutic implications

Biliary cancers (BCs) are a diverse group of tumors that arise from the bile duct epithelium and are divided into cholangiocarcinomas of the intrahepatic and extrahepatic cholangiocarcinoma (EHCC) and cancer of the gallbladder. Despite improvements in treatment and diagnosis, BCs are often diagnosed at an advanced stage and associated with poor prognosis and limited treatment options. Recent discoveries have allowed us to have a better understanding of the genomic diversity in BC, and identify genes that are likely contributing to its pathogenesis, proliferation and treatment resistance. Additionally, these advances have allowed us to reason that each anatomic group within BC behave as distinct diseases, with differences in prognosis and outcomes. Based on this knowledge, recent advances have allowed us to identify actionable mutations that form rational therapeutic targets with novel agents, where their relevance will be better understood through the completion of prospective clinical trials.

Regulators of Cholangiocyte Proliferation

Cholangiocytes, a small population of cells within the normal liver, have been the focus of a significant amount of research over the past two decades because of their involvement in cholangiopathies such as primary sclerosing cholangitis and primary biliary cholangitis. This article summarizes landmark studies in the field of cholangiocyte physiology and aims to provide an updated review of biliary pathogenesis. The historical approach of rodent extrahepatic bile duct ligation and the relatively recent utilization of transgenic mice have led to significant discoveries in cholangiocyte pathophysiology. Cholangiocyte physiology is a complex system based on heterogeneity within the biliary tree and a number of signaling pathways that serve to regulate bile composition. Studies have expanded the list of neuropeptides, neurotransmitters, and hormones that have been shown to be key regulators of proliferation and biliary damage. The peptide histamine and hormones, such as melatonin and angiotensin, angiotensin, as well as numerous sex hormones, have been implicated in cholangiocyte proliferation during cholestasis. Numerous pathways promote cholangiocyte proliferation during cholestasis, and there is growing evidence to suggest that cholangiocyte proliferation may promote hepatic fibrosis. These pathways may represent significant therapeutic potential for a subset of cholestatic liver diseases that currently lack effective therapies.

Combination of anti-L1 cell adhesion molecule antibody and gemcitabine or cisplatin improves the therapeutic response of intrahepatic cholangiocarcinoma

Cholangiocarcinoma has a poor prognosis and is refractory to conventional chemotherapy and radiation therapy. Improving survival of patients with advanced cholangiocarcinoma urgently requires the development of new effective targeted therapies in combination with chemotherapy. We previously developed a human monoclonal antibody (mAb) Ab417 that binds to both the human and mouse L1 cell adhesion molecule (L1CAM) with high affinities. In the present study, we observed that Ab417 exhibited tumor targeting ability in biodistribution studies and dose-dependent tumor growth inhibition in an intrahepatic cholangiocarcinoma (Choi-CK) xenograft mouse model. Regarding the mechanism of action, Ab417 was internalized into the tumor cells and thereby down-regulated membrane L1CAM, and inhibited tumor growth by reducing tumor cell proliferation in vivo. Gemcitabine inhibited the tumor growth in a dose-dependent manner in the Choi-CK xenograft model. However, cisplatin inhibited the tumor growth moderately and not in a dose-dependent way, suggesting that the tumors may have developed resistance to apoptosis induced by cisplatin. Combined treatment with Ab417 and gemcitabine or cisplatin exerted enhanced tumor growth inhibition compared to treatment with antibody or drug alone. The results suggest that Ab417 in combination with chemotherapy may have potential as a new therapeutic regimen for cholangiocarcinoma. Our study is the first to show an enhanced therapeutic effect of a therapeutic antibody targeting L1CAM in combination with chemotherapy in cholangiocarcinoma models.

Epithelial-mesenchymal transition in cholangiocarcinoma: From clinical evidence to regulatory networks

Cholangiocarcinoma (CCA) is an aggressive tumor with a poor prognosis due to its late clinical presentation and the lack of effective non-surgical therapies. Unfortunately, most of the patients are not eligible for curative surgery owing to the presence of metastases at the time of diagnosis. Therefore, it is important to understand the steps leading to cell dissemination in patients with CCA. To metastasize from the primary site, cancer cells must acquire migratory and invasive properties by a cell plasticity-promoting phenomenon known as epithelial-mesenchymal transition (EMT). EMT is a reversible dynamic process by which epithelial cells gradually adopt structural and functional characteristics of mesenchymal cells, and has lately become a centre of attention in the field of metastatic dissemination. In the present review, we aim to provide an extensive overview of the current clinical data and the prognostic value of different EMT markers that have been analysed in CCA. We summarize all the regulatory networks implicated in EMT from the membrane receptors to the main EMT-inducing transcription factors (SNAIL, TWIST and ZEB). Furthermore, since a tumor is a complex structure not exclusively formed by tumor cells, we also address the prominent role of the main cell types of the desmoplastic stroma that characterizes CCA in the regulation of EMT. Finally, we discuss the therapeutic considerations and difficulties faced to develop an effective anti-EMT treatment due to the redundancies and bypasses among the pathways regulating EMT.

[Inflammation and Cancer Development in Pancreatic and Biliary Tract Cancer]

Chronic inflammation has been known to be a risk for many kinds of cancers, including pancreatic and biliary tract cancer. Recently, inflammatory process has emerged as a key mediator of cancer development and progression. Many efforts with experimental results have been given to identify the underlying mechanisms that contribute to inflammation-induced tumorigenesis. Diverse inflammatory pathways have been investigated and inhibitors for inflammation-related signaling pathways have been developed for cancer treatment. This review will summarize recent outcomes about this distinctive process in pancreatic and biliary tract cancer. Taking this evidence into consideration, modulation of inflammatory process will provide useful options for pancreatic and biliary tract cancer treatment.

The rise of the FGFR inhibitor in advanced biliary cancer: the next cover of time magazine?

Cholangiocarcinomas (CCAs) are heterogeneous tumors arising from the biliary tract with features of cholangiocyte differentiation. CCAs are aggressive tumors with limited treatment options and poor overall survival. Only a subset of CCA patients with early stage disease can avail potentially curative treatment options. For advanced biliary tract tumors, currently there are limited effective treatment modalities. Recent advances have provided greater insight into the genomic landscape of CCAs. The fibroblast growth factor receptor (FGFR) pathway is involved in key cellular processes essential to survival and differentiation. Accordingly, aberrant FGFR signaling has significant oncogenic potential. Recent discovery of FGFR2 gene fusions in CCA has heightened interest in FGFR inhibition in advanced biliary tract cancer. These findings have served as a catalyst for ongoing clinical investigation of FGFR inhibition in CCA patients with various FGFR signaling abnormalities. Herein, we review FGFR aberrations in CCA and their prognostic implications, FGFR targeting as a viable therapeutic option in advanced biliary tract malignancies, and future directions for development of combination approaches utilizing FGFR inhibition.

Lovastatin overcomes gefitinib resistance through TNF-α signaling in human cholangiocarcinomas with different LKB1 statuses in vitro and in vivo

Gefitinib resistance has been shown to complicate cancer therapy. Lovastatin is a proteasome inhibitor that enhances gefitinib-induced antiproliferation in non-small cell lung cancer. The objective of this study is to investigate the mechanism of lovastatin-induced antiproliferation in gefitinib-resistant human cholangiocarcinoma.

Two gefitinib-resistant cholangiocarcinoma cell lines, SSP-25 and HuH-28, were used in this study to determine how to compensate gefitinib resistance. The combined effect of these two drugs was examined using the MTT assay, qPCR, immunoblotting, flow cytometry, and in vivo xenograft. Results indicated that lovastatin enhanced TNF-α-induced cell death in vitro. In addition, the combination of lovastatin with gefitinib enhanced accumulation of TNF-α. Furthermore, the treatment induced a synergistic cytotoxic effect and antiproliferation through apoptosis in SSP-25 cells and cell cycle arrest in HuH-28 cells. Reproductive results were also observed in in vivo xenografts. These observations suggest that the combination of gefitinib and lovastatin might have additive antiproliferative effects against gefitinib-resistant cholangiocarcinoma cells. Based on these observations, we concluded that the combination of gefitinib and lovastatin could be used to overcome gefitinib resistance in cholangiocarcinoma cells.

Expert consensus document: Cholangiocarcinoma: current knowledge and future perspectives consensus statement from the European Network for the Study of Cholangiocarcinoma (ENS-CCA)

Cholangiocarcinoma (CCA) is a heterogeneous group of malignancies with features of biliary tract differentiation. CCA is the second most common primary liver tumour and the incidence is increasing worldwide. CCA has high mortality owing to its aggressiveness, late diagnosis and refractory nature. In May 2015, the "European Network for the Study of Cholangiocarcinoma" (ENS-CCA: www.enscca.org or www.cholangiocarcinoma.eu) was created to promote and boost international research collaboration on the study of CCA at basic, translational and clinical level. In this Consensus Statement, we aim to provide valuable information on classifications, pathological features, risk factors, cells of origin, genetic and epigenetic modifications and current therapies available for this cancer. Moreover, future directions on basic and clinical investigations and plans for the ENS-CCA are highlighted.

TGR5 is essential for bile acid-dependent cholangiocyte proliferation in vivo and in vitro

OBJECTIVE

Cholestatic liver diseases in humans as well as bile acid (BA)-feeding and common bile duct ligation (CBDL) in rodents trigger hyperplasia of cholangiocytes within the portal fields. Furthermore, elevation of BA levels enhances proliferation and invasiveness of cholangiocarcinoma (CCA) cells in animal models, thus promoting tumour progression. TGR5 is a G-protein coupled BA receptor, which is highly expressed in cholangiocytes and postulated to mediate the proliferative effects of BA.

DESIGN

BA-dependent cholangiocyte proliferation was examined in TGR5-knockout and wild type mice following cholic acid (CA)-feeding and CBDL. TGR5-dependent proliferation and protection from apoptosis was studied in isolated cholangiocytes and CCA cell lines following stimulation with TGR5 ligands and kinase inhibitors. TGR5 expression was analysed in human CCA tissue.

RESULTS

Cholangiocyte proliferation was significantly reduced in TGR5-knockout mice in response to CA-feeding and CBDL. Taurolithocholic acid and TGR5-selective agonists induced cholangiocyte proliferation through elevation of reactive oxygen species and cSrc mediated epidermal growth factor receptor transactivation and subsequent Erk1/2 phosphorylation only in wild type but not in TGR5-knockout-derived cells. In human CCA tissue TGR5 was overexpressed and the pathway of TGR5-dependent proliferation via epidermal growth factor receptor and extracellular signal-regulated kinase (ERK)1/2 activation also translated to CCA cell lines. Furthermore, apoptosis was inhibited by TGR5-dependent CD95 receptor serine phosphorylation.

CONCLUSIONS

TGR5 is an important mediator of BA-induced cholangiocyte proliferation in vivo and in vitro. Furthermore, TGR5 protects cholangiocytes from death receptor-mediated apoptosis. These mechanisms may protect cholangiocytes from BA toxicity under cholestatic conditions, however, they may trigger proliferation and apoptosis resistance in malignantly transformed cholangiocytes, thus promoting CCA progression.

[Medical management of cholangiocarcinomas in 2015]

Cholangiocarcinoma is a rare malignancy carrying a poor prognosis. Most patients are diagnosed with advanced-stage disease and are then ineligible for surgical resection, which is the only potentially curative therapeutic modality. The aim of this article is to provide an up-to-date review of medical management of patients with cholangiocarcinoma. The benefit of adjuvant therapy in patients undergoing curative-intent surgery is under evaluation. Combination chemotherapy with gemcitabine and platinum is the standard first-line treatment for patients with advanced cholangiocarcinoma. Targeted agents are not currently recommended due to limited data on use in this setting. The role of second-line chemotherapy is not established in advanced cholangiocarcinoma. Identification of predictive and prognostic markers to select patients who could benefit from second-line therapy is a major issue. A better understanding of the biological and molecular mechanisms underlying the carcinogenesis and the phenotypic heterogeneity of cholangiocarcinoma may path the way of new therapeutic strategies.

EGFR Signaling in Liver Diseases

The epidermal growth factor receptor (EGFR) is a transmembrane receptor tyrosine kinase that is activated by several ligands leading to the activation of diverse signaling pathways controlling mainly proliferation, differentiation, and survival. The EGFR signaling axis has been shown to play a key role during liver regeneration following acute and chronic liver damage, as well as in cirrhosis and hepatocellular carcinoma (HCC) highlighting the importance of the EGFR in the development of liver diseases. Despite the frequent overexpression of EGFR in human HCC, clinical studies with EGFR inhibitors have so far shown only modest results. Interestingly, a recent study has shown that in human HCC and in mouse HCC models the EGFR is upregulated in liver macrophages where it plays a tumor-promoting function. Thus, the role of EGFR in liver diseases appears to be more complex than what anticipated. Further studies are needed to improve the molecular understanding of the cell-specific signaling pathways that control disease development and progression to be able to develop better therapies targeting major components of the EGFR signaling network in selected cell types. In this review, we compiled the current knowledge of EGFR signaling in different models of liver damage and diseases, mainly derived from the analysis of HCC cell lines and genetically engineered mouse models (GEMMs).

Primary Sclerosing Cholangitis as a Premalignant Biliary Tract Disease: Surveillance and Management

Primary sclerosing cholangitis (PSC) is a premalignant biliary tract disease that confers a significant risk for the development of cholangiocarcinoma (CCA). The chronic biliary tract inflammation of PSC promotes pro-oncogenic processes such as cellular proliferation, induction of DNA damage, alterations of the extracellular matrix, and cholestasis. The diagnosis of malignancy in PSC can be challenging because inflammation-related changes in PSC may produce dominant biliary tract strictures mimicking CCA. Biomarkers such as detection of methylated genes in biliary specimens represent noninvasive techniques that may discriminate malignant biliary ductal changes from PSC strictures. However, conventional cytology and advanced cytologic techniques such as fluorescence in situ hybridization for polysomy remain the practice standard for diagnosing CCA in PSC. Curative treatment options of malignancy arising in PSC are limited. For a subset of patients selected by using stringent criteria, liver transplantation after neoadjuvant chemoradiation is a potential curative therapy. However, most patients have advanced malignancy at the time of diagnosis. Advances directed at identifying high-risk patients, early cancer detection, and development of chemopreventive strategies will be essential to better manage the cancer risk in this premalignant disease. A better understanding of dysplasia definition and especially its natural history is also needed in this disease. Herein, we review recent developments in our understanding of the risk factors, pathogenic mechanisms of PSC associated with CCA, as well as advances in early detection and therapies.

Vertical Targeting of AKT and mTOR as Well as Dual Targeting of AKT and MEK Signaling Is Synergistic in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer, and the third most common cause of cancer related death worldwide. The multi-kinase inhibitor Sorafenib represents the only systemic treatment option until today, and results from clinical trials with allosteric mTOR inhibitors were sobering. Since the PI3K/AKT/mTOR and RAF/MEK/ERK signaling pathways are frequently upregulated in HCC, we have analyzed the effects of AKT inhibitor MK-2206, MEK inhibitor AZD6244 (ARRY 142886) and mTOR kinase inhibitor AZD8055, given as single drugs or in combination, on proliferation and apoptosis of three HCC cell lines in vitro. We show that all three inhibitor combinations synergistically inhibit proliferation of the three HCC cell lines, with the strongest synergistic effect observed after vertical inhibition of AKT and mTORC1/2. We demonstrate that AKT kinase activity is restored 24h after blockade of mTORC1/2 by increased phosphorylation of T308, providing a rationale for combined targeting of AKT and mTOR inhibition in HCC. Our data suggest that a combination of inhibitors targeting those respective pathways may be a viable approach for future application in patients with hepatocellular carcinoma.

Lipopolysaccharide (LPS)-Induced Biliary Epithelial Cell NRas Activation Requires Epidermal Growth Factor Receptor (EGFR)

Cholangiocytes (biliary epithelial cells) actively participate in microbe-induced proinflammatory responses in the liver and contribute to inflammatory and infectious cholangiopathies. We previously demonstrated that cholangiocyte TLR-dependent NRas activation contributes to proinflammatory/ proliferative responses. We test the hypothesis that LPS-induced activation of NRas requires the EGFR. SV40-transformed human cholangiocytes (H69 cells), or low passage normal human cholangiocytes (NHC), were treated with LPS in the presence or absence of EGFR or ADAM metallopeptidase domain 17 (TACE) inhibitors. Ras activation assays, quantitative RT-PCR, and proliferation assays were performed in cells cultured with or without inhibitors or an siRNA to Grb2. Immunofluorescence for phospho-EGFR was performed on LPS-treated mouse samples and specimens from patients with primary sclerosing cholangitis, primary biliary cirrhosis, hepatitis C, and normal livers. LPS-treatment induced an association between the TLR/MyD88 and EGFR/Grb2 signaling apparatus, NRas activation, and EGFR phosphorylation. NRas activation was sensitive to EGFR and TACE inhibitors and correlated with EGFR phosphorylation. The TACE inhibitor and Grb2 depletion prevented LPS-induced IL6 expression (p<0.05) and proliferation (p<0.01). Additionally, cholangiocytes from LPS-treated mouse livers and human primary sclerosing cholangitis (PSC) livers exhibited increased phospho-EGFR (p<0.01). Moreover, LPS-induced mouse cholangiocyte proliferation was inhibited by concurrent treatment with the EGFR inhibitor, Erlotinib. Our results suggest that EGFR is essential for LPS-induced, TLR4/MyD88-mediated NRas activation and induction of a robust proinflammatory cholangiocyte response. These findings have implications not only for revealing the signaling potential of TLRs, but also implicate EGFR as an integral component of cholangiocyte TLR-induced proinflammatory processes.

A randomized, multicenter, phase II study of vandetanib monotherapy versus vandetanib in combination with gemcitabine versus gemcitabine plus placebo in subjects with advanced biliary tract cancer: the VanGogh study

BACKGROUND

The management of biliary tract cancers (BTCs) is complex due to limited data on the optimal therapeutic approach. This phase II multicenter study evaluated the efficacy and tolerability of vandetanib monotherapy compared with vandetanib plus gemcitabine or gemcitabine plus placebo in patients with advanced BTC.

PATIENTS AND METHODS

Patients were randomized in a 1 : 1 : 1 ratio to three treatment groups: vandetanib 300 mg monotherapy (V), vandetanib 100 mg plus gemcitabine (V/G), gemcitabine plus placebo (G/P). Vandetanib (300 mg or 100 mg) or placebo was given in single oral daily doses. Gemcitabine 1000 mg/m(2) was i.v. infused on day 1 and day 8 of each 21-day cycle. The primary end point was progression-free survival (PFS). Secondary end points were: objective response rate (ORR), disease control rate, overall survival, duration of response, performance status and safety outcomes.

RESULTS

A total of 173 patients (mean age 63.6 years) were recruited at 19 centers across Italy. Median (95% confidence intervals) PFS (days) were 105 (72-155), 114 (91-193) and 148 (71-225), respectively, for the V, V/G and G/P treatment groups, with no statistical difference among them (P = 0.18). No statistical difference between treatments was observed for secondary end points, except ORR, which slightly favored the V/G combination over other treatments. The proportion of patients reporting adverse events (AEs) was similar for the three groups (96.6% in V arm, 91.4% in the V/G arm and 89.3% in the G/P arm).

CONCLUSIONS

Vandetanib treatment did not improve PFS in patients with advanced BTC. The safety profile of vandetanib did not show any additional AEs or worsening of already known AEs.

CLINICAL TRIAL NUMBER

NCT00753675.