Molecular pathology of biliary tract cancers

Escherichia coli-Induced cGLIS3-Mediated Stress Granules Activate the NF-κB Pathway to Promote Intrahepatic Cholangiocarcinoma Progression

Patients with concurrent intrahepatic cholangiocarcinoma (ICC) and hepatolithiasis generally have poor prognoses. Hepatolithiasis is once considered the primary cause of ICC, although recent insights indicate that bacteria in the occurrence of hepatolithiasis can promote the progression of ICC. By constructing in vitro and in vivo ICC models and patient-derived organoids (PDOs), it is shown that Escherichia coli induces the production of a novel RNA, circGLIS3 (cGLIS3), which promotes tumor growth. cGLIS3 binds to hnRNPA1 and G3BP1, resulting in the assembly of stress granules (SGs) and suppression of hnRNPA1 and G3BP1 ubiquitination. Consequently, the IKKα mRNA is blocked in SGs, decreasing the production of IKKα and activating the NF-κB pathway, which finally results in chemoresistance and produces metastatic phenotypes of ICC. This study shows that a combination of Icaritin (ICA) and gemcitabine plus cisplatin (GP) chemotherapy can be a promising treatment strategy for ICC.

PRECLINICAL MODELS OF LIVER CÂNCER

•In this review, we described different murine models of carcinogenesis: classic models, new transgenic and combined models, that reproduce the key points for HCC and CCA genesis allowing a better understanding of its genetic physiopathological, and environmental abnormalities. •Each model has its advantages, disadvantages, similarities, and differences with the corresponding human disease and should be chosen according to the specificity of the study. Ultimately, those models can also be used for testing new anticancer therapeutic approaches. •Cholangiocarcinoma has been highlighted, with an increase in prevalence. This review has an important role in understanding the pathophysiology and the development of new drugs. Background - This manuscript provides an overview of liver carcinogenesis in murine models of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). Objective - A review through MEDLINE and EMBASE was performed to assess articles until August 2022.Methods - Search was conducted of the entire electronic databases and the keywords used was HCC, CCA, carcinogenesis, animal models and liver. Articles exclusion was based on the lack of close relation to the subject. Carcinogenesis models of HCC include HCC induced by senescence in transgenic animals, HCC diet-induced, HCC induced by chemotoxicagents, xenograft, oncogenes, and HCC in transgenic animals inoculated with B and C virus. The models of CCA include the use of dimethylnitrosamine (DMN), diethylnitrosamine (DEN), thioacetamide (TAA), and carbon tetrachloride (CCl4). CCA murine models may also be induced by: CCA cells, genetic manipulation, Smad4, PTEN and p53 knockout, xenograft, and DEN-left median bile duct ligation. Results - In this review, we described different murine models of carcinogenesis that reproduce the key points for HCC and CCA genesis allowing a better understanding of its genetic, physiopathological, and environmental abnormalities. Conclusion - Each model has its advantages, disadvantages, similarities, and differences with the corresponding human disease and should be chosen according to the specificity of the study. Ultimately, those models can also be used for testing new anticancer therapeutic approaches.

Helicobacter bilis infection induces oxidative stress in and enhances the proliferation of human cholangiocytes

BACKGROUND

Helicobacter bilis, an enterohepatic Helicobacter species, represents a carcinogenic risk factor for cholangiocytes owing to the prevalence of infections in patients with biliary tract cancer, cholecystitis, and pancreaticobiliary maljunction. However, the effect of H. bilis infection on cholangiocytes and the process and mechanism of carcinogenesis are not known. We aimed to determine the effects of H. bilis on cholangiocytes, focusing on inflammation and oxidative stress.

MATERIALS AND METHODS

Helicobacter bilis and MMNK-1 cells were cocultured for 24 h and inflammatory cytokine secretion was evaluated. Furthermore, MMNK-1 cell proliferation, intracellular reactive oxidant species (ROS) production, and DNA damage caused by ROS were investigated. All factors were compared with and without H. bilis infection.

RESULTS

Interleukin (IL)-6 and IL-8 secretion were significantly increased in MMNK-1 cocultures with H. bilis (IL-6, 24.3 ± 12.2 vs. 271.1 ± 286.4 pg/ml; IL-8, 167.6 ± 78.7 vs. 1085.1 ± 1047.1 pg/ml, p < .05). MMNK-1 proliferation was also significantly higher in H. bilis cocultures (1.05 ± 0.02 vs. 1.00-fold, respectively; p < .05). Coculturing enhanced the production of ROS in MMNK-1 cells depending on the cell concentration of H. bilis (1.0 vs. 1.17 ± 0.06, p < .05); however, DNA injury was not observed in cocultures with H. bilis (5.35 ± 0.87 vs. 6.08 ± 0.55 pg/μl, p = .06).

CONCLUSIONS

Helicobacter bilis infection induced ROS production in and enhanced the proliferation of cholangiocytes.

Molecular Mechanisms Linking Risk Factors to Cholangiocarcinoma Development

The poor prognosis of cholangiocarcinoma in humans is related to several factors, such as (i) the heterogeneity of the disease, (ii) the late onset of symptoms and (iii) the limited comprehension of the carcinogenic pathways determining neoplastic changes, which all limit the pursuit of appropriate treatment. Several risk factors have been recognized, including different infective, immune-mediated, and dysmorphogenic disorders of the biliary tree. In this review, we report the details of possible mechanisms that lead a specific premalignant pathological condition to become cholangiocarcinoma. For instance, during liver fluke infection, factors secreted from the worms may play a major role in pathogenesis. In primary sclerosing cholangitis, deregulation of histamine and bile-acid signaling may determine important changes in cellular pathways. The study of these molecular events may also shed some light on the pathogenesis of sporadic (unrelated to risk factors) forms of cholangiocarcinoma, which represent the majority (nearly 75%) of cases.

Anti-Proliferative Effects of Compound A and Its Effect in Combination with Cisplatin in Cholangiocarcinoma Cells

BACKGROUND

Cholangiocarcinoma (CCA) is a fatal cancer with high resistance to anticancer drugs.  The development of new drugs or compounds to be used alone or in combination with currently available chemotherapeutic agents to improve the treatment of CCA is needed. Compound A (CpdA), which is a small plant-derived glucocorticoid receptor modulator, strongly inhibited the growth and survival of several cancers.  However, the effect of CpdA on cholangiocarcinoma has not been elucidated. The aim of this study was to investigate the effect of CpdA on CCA.

METHODS

Cytotoxicity of CpdA was tested in primary cells including peripheral blood mononuclear cells (PBMCs), fibroblasts, and human umbilical vein endothelial cells (HUVECs), as well as on CCA cell lines (KKU-100, KKU-055, and KKU-213) was examined. Cell cycle distribution and IL-6 expression was assessed by flow cytometry and real-time polymerase chain reaction, respectively.  The effect of combination CpdA and cisplatin was evaluated by cell viability assay.

RESULTS

CpdA significantly inhibited cell cycle at G1 phase in CCA cell lines, and reduced IL-6 mRNA expression.  However, combination CpdA and cisplatin did not enhance the inhibitory effect. TGFβR-II expression was increased in CCA cells after the combination treatment.

CONCLUSIONS

These results indicate the potential of CpdA for CCA treatment. However, combination treatment with CpdA and cisplatin increased CCA cell survival. The molecular mechanism is likely attributable to promotes cell survival via the TGFβR-II signaling pathway. The combination of CpdA with other anticancer drugs for CCA treatment should be further examined.

Aberrant Expression of Cell Cycle Regulator 14-3-3-σ and E-Cadherin in a Metastatic Cholangiocarcinoma in a Vervet Monkey (Chlorocebus pygerythrus)

We present a unique case of metastatic cholangiocarcinoma with concurrent abdominal cestodiasis in an African green monkey (Chlorocebus pygerythrus) that presented with respiratory insufficiency and abdominal discomfort. There were multiple white-grey masses in the liver and colonic serosa alongside intra-abdominal parasitic cysts. Histopathologically, the liver masses were composed of poorly-differentiated epithelial cells that formed densely cellular solid areas and trabeculae. The neoplastic cells were strongly immunopositive for CK7 but negative for Hep-Par1 antigen, which confirmed a diagnosis of cholangiocarcinoma. Interestingly, there was strong and diffuse neoexpression in the tumour of the cell cycle regulator 14-3-3σ, which is not constitutively expressed in normal liver. There was aberrantly strong expression of E-cadherin, a key cell-cell adhesion protein, in neoplastic cells with evidence of cytoplasmic internalization. This is the first immunohistochemical analysis of 14-3-3σ and E-cadherin in a liver neoplasm in an animal species and the use of these markers requires further investigation in animal liver neoplasms.

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.

The Role of Stroma in Cholangiocarcinoma: The Intriguing Interplay between Fibroblastic Component, Immune Cell Subsets and Tumor Epithelium

Cholangiocarcinoma (CCA) is a severe and mostly intractable adenocarcinoma of biliary epithelial cells. A typical feature of CCA is its highly desmoplastic microenvironment containing fibrogenic connective tissue and an abundance of immune cells (T lymphocytes, Natural Killer (NK) cells, and macrophages) infiltrating tumor epithelium. This strong desmoplasia is orchestrated by various soluble factors and signals, suggesting a critical role in shaping a tumor growth-permissive microenvironment that is responsible for CCA poor clinical outcome. Indeed stroma not only provides an abundance of factors that facilitate CCA initiation, growth and progression, but also a prejudicial impact on therapeutic outcome. This review will give an overview of tumor-stroma signaling in a microenvironment critically regulating CCA development and progression. Identification of CCA secreted factors by both the fibroblast component and immune cell subsets might provide ample opportunities for pharmacological targeting of this type of cancer.

Molecular profiling of intrahepatic cholangiocarcinoma: the search for new therapeutic targets

Intrahepatic cholangiocarcinoma (iCCA) is the second most frequent primary tumor of the liver and a highly lethal disease. Therapeutic options for advanced iCCA are limited and ineffective due to the largely incomplete understanding of the molecular pathogenesis of this deadly tumor. Areas covered: The present review article outlines the main studies and resulting discoveries on the molecular profiling of iCCA, with a special emphasis on the different techniques used for this purpose, the diagnostic and prognostic markers identified, as well as the genes and pathways that could be potentially targeted with innovative therapies. Expert commentary: Molecular profiling has led to the identification of distinct iCCA subtypes, characterized by peculiar genetic alterations and transcriptomic features. Targeted therapies against some of the identified genes are ongoing and hold great promise to improve the prognosis of iCCA patients.

Cholangiocarcinoma

Biliary tract cancer accounts for <1% of all cancers and affects chiefly an elderly population, with predominance in men. We distinguish cholangiocarcinoma (intrahepatic, hilar and distal) and gallbladder cancer, with different pathogenesis and prognosis. The treatment is based on surgery (whenever possible), radiotherapy in selected cases, and chemotherapy. The standard cytotoxic treatment for advanced/metastatic disease is represented by the combination of gemcitabine and cisplatin, whereas fluoropyrimidines are generally administered in second line setting. At the present time, no biologic drug demonstrated a clear efficacy in this cancer, although the molecular characterisation could provide a promising basis for experimental treatments. A good supportive care and an early palliative care are warranted in most patients and should be delivered as a part of a global approach.

High expression of protein tyrosine kinase 7 significantly associates with invasiveness and poor prognosis in intrahepatic cholangiocarcinoma

Background

The incidence, prevalence, and mortality of intrahepatic cholangiocarcinoma (ICC) are increasing worldwide. Protein tyrosine kinase-7 (PTK7) is upregulated in many common human cancers. However, its expression in ICC has not been studied. The present study aimed to explore the underlying mechanism of PTK7 in ICC.

Materials and Methods

The role of PTK7 was studied in vitro by suppressing PTK7 expression in ICC cell lines. The in vivo effect of PTK7 was evaluated using a nude mouse model inoculated with a human ICC cell line. We also examined the role of PTK7 in human ICC samples.

Results

Cells with high PTK7 expression exhibited higher proliferation, DNA synthesis, invasion, and migration abilities than did cells with low PTK7 expression. The knockdown of PTK7 with small interfering RNA (siRNA) in high PTK7 expressing cells resulted in impairment of invasion, migration, and DNA synthesis through the regulation of several cell-cycle-related proteins. It also induced cell apoptosis and decreased phospho-RhoA expression. In a xenograft nude mouse model, PTK7 siRNA resulted in a reduction of the tumor size, compared with scrambled siRNA injection. PTK7 expression was higher in human ICC than in the normal bile duct. Patients with low expression of PTK7 had a longer disease-free survival and overall survival than those with high expression.

Conclusions

PTK7 expression plays an important role in the invasiveness of ICC cells and leads to a poor prognosis in ICC patients. Thus, PTK7 can be used as a prognostic indicator, and the inhibition of PTK7 expression could be a new therapeutic target for ICC.

Hydrodynamic transfection for generation of novel mouse models for liver cancer research

Primary liver cancers, including hepatocellular carcinoma and intrahepatic cholangiocarcinoma, are leading causes of cancer-related death worldwide. Recent large-scale genomic approaches have identified a wide number of genes whose deregulation is associated with hepatocellular carcinoma and intrahepatic cholangiocarcinoma development. Murine models are critical tools to determine the oncogenic potential of these genes. Conventionally, transgenic or knockout mouse models are used for this purpose. However, several limitations apply to the latter models. Herein, we review a novel approach for stable gene expression in mouse hepatocytes by hydrodynamic injection in combination with Sleeping Beauty-mediated somatic integration. This method represents a flexible, reliable, and cost-effective tool to generate preclinical murine models for liver cancer research. Furthermore, it can be used as an in vivo transfection method to study biochemical cross talks among multiple pathways along hepatocarcinogenesis and to test the therapeutic potential of drugs against liver cancer.

Inflammation-related DNA damage and expression of CD133 and Oct3/4 in cholangiocarcinoma patients with poor prognosis

Nitrative and oxidative DNA damage plays an important role in inflammation-related carcinogenesis. Chronic inflammation such as parasite infection and primary sclerosing cholangitis can be an etiological factor of cholangiocarcinoma. Using a proteomic approach and double-fluorescent staining, we identified high expression and colocalization of albumin and cytokeratin-19 in liver fluke-associated cholangiocarcinoma tissues, compared with normal livers from cholangiocarcinoma patients and cadaveric donors, respectively. Albumin was detected not only in cells of hyperplastic bile ducts and cholangiocarcinoma, but also in liver stem/progenitor cell origin, such as canal of Hering, ductules, and ductular reactions, suggesting the involvement of stem/progenitor cells in cholangiocarcinoma development. To clarify the involvement of liver stem/progenitor cells in cholangiocarcinoma, we examined several stem/progenitor cell markers (CD133, CD44, OV6, and Oct3/4) in cholangiocarcinoma tissues analyzed by immunohistochemical staining, and measured 8-oxodG levels by using HPLC-ECD as an inflammation-related DNA lesion. In addition, a stem/progenitor cell factor Bmi1, 8-nitroguanine (formed during nitrative DNA damage), DNA damage response (DDR) proteins (phosphorylated ATM and γ-H2AX), and manganese-SOD (Mn-SOD) were analyzed by immunohistochemistry. Stem/progenitor cell markers (CD133, OV6, CD44, and Oct3/4) were positively stained in 56, 38, 47, and 56% of 34 cholangiocarcinoma cases, respectively. Quantitative analysis of 8-oxodG revealed significantly increased levels in CD133- and/or Oct3/4-positive tumor tissues compared to negative tumor tissues, as well as 8-nitroguanine formation detected by immunohistochemistry. In the cases of CD44- and/or OV6-positive tissue, no significant difference was observed. Cholangiocarcinoma patients with CD133- and/or Oct3/4-positive tumor tissues showed significantly lower expression of Mn-SOD and higher DDR protein, γ-H2AX. Moreover, CD133- and/or Oct3/4-positive cholangiocarcinoma patients had significant associations with tumor histology types, tumor stage, and poor prognoses. Our results suggest that CD133 and Oct3/4 in cholangiocarcinoma are associated with increased formation of DNA lesions and the DDR protein, which may be involved in genetic instability and lead to cholangiocarcinoma development with aggressive clinical features.

Bile acids affect the growth of human cholangiocarcinoma via NF-kB pathway

We observed that free bile acids (CA, DCA, and CDCA) inhibited the growth of cholangiocarcinoma cells by promoting cell apoptosis, while the conjugated bile acids (GCA, GDCA, and GCDCA) stimulated cell growth. Consistently, we found that GDCA stimulated tumor growth and CDCA decreased tumor growth in xenografted mice. Further, the phosphorylated IkB was downregulated by free bile acids, and was upregulated by the conjugated bile acids. IL-6 and COX-2 were decreased by the free bile acids and increased by the conjugated bile acids. Collectively, these results suggest that the bile acids regulate the growth of cholangiocarcinoma by modulating NF-kB pathway.

Liver carcinogenesis: rodent models of hepatocarcinoma and cholangiocarcinoma

Hepatocellular carcinoma and cholangiocarcinoma are primary liver cancers, both represent a growing challenge for clinicians due to their increasing morbidity and mortality. In the last few years a number of in vivo models of hepatocellular carcinoma and cholangiocarcinoma have been developed. The study of these models is providing a significant contribution in unveiling the pathophysiology of primary liver malignancies. They are also fundamental tools to evaluate newly designed molecules to be tested as new potential therapeutic agents in a pre-clinical set. Technical aspects of each model are critical steps, and they should always be considered in order to appropriately interpret the findings of a study or its planning. The purpose of this review is to describe the technical and experimental features of the most significant rodent models, highlighting similarities or differences between the corresponding human diseases. The first part is dedicated to the discussion of models of hepatocellular carcinoma, developed using toxic agents, or through dietary or genetic manipulations. In the second we will address models of cholangiocarcinoma developed in rats or mice by toxin administration, genetic manipulation and/or bile duct incannulation or surgery. Xenograft or syngenic models are also proposed.

Hepatitis B virus infection increases the risk of cholangiocarcinoma: a meta-analysis and systematic review

BACKGROUND AND AIM

A number of studies have shown that hepatitis virus infections may be associated with cholangiocarcinoma (CC). However, the relationship between hepatitis B virus (HBV) infection and CC, especially intrahepatic cholangiocarcinoma (ICC), is still controversial.

METHODS

Relevant studies were identified by searching PUBMED, EMBASE and Web of Science Datebases up to September 2011. Pooled risk estimates were calculated using a random-effects model. Potential sources of heterogeneity were performed by subgroup analyses. A total of 18 papers were included in this meta-analysis.

RESULTS

The pooled risk estimate of all studies showed a statistically significant increased risk of CC among individuals with HBV infection (rate ratio [RR]: 2.66; 95% confidence interval [CI]: 1.97, 3.60). Compared with those without HBV infection, persons with HBV infection had an increased risk of intra-CC (ICC) (RR: 3.42; 95% CI: 2.46, 43.74), extrahepatic CC (OR: 1.46; 95% CI: 0.98, 2.17), and CC (OR: 2.03; 95% CI: 1.15, 3.56). In a subgroup analysis of HBV infection and risk of ICC, the pooled risk estimate of studies in Asians (RR: 3.63; 95% CI: 2.56, 5.13) was higher than that in non-Asians (RR: 1.93; 95% CI: 0.78, 4.76). A Begg funnel plot and Egger test revealed no evidence for publication bias.

CONCLUSIONS

This meta-analysis shows that HBV is associated with increased risk of CC, especially for ICC. Further investigation is needed to focus on the mechanism by which HBV may be involved in the pathogenesis of CC.

Multiple cells of origin in cholangiocarcinoma underlie biological, epidemiological and clinical heterogeneity

Recent histological and molecular characterization of cholangiocarcinoma (CCA) highlights the heterogeneity of this cancer that may emerge at different sites of the biliary tree and with different macroscopic or morphological features. Furthermore, different stem cell niches have been recently described in the liver and biliary tree, suggesting this as the basis of the heterogeneity of intrahepatic (IH)- and extrahepatic (EH)-CCAs, which are two largely different tumors from both biological and epidemiological points of view. The complexity of the organization of the liver stem cell compartments could underlie the CCA clinical-pathological heterogeneity and the criticisms in classifying primitive liver tumors. These recent advances highlight a possible new classification of CCAs based on cells of origin and this responds to the need of generating homogenous diagnostic, prognostic and, hopefully, therapeutic categories of IH- and EH-CCAs.

Molecular pathogenesis of cholangiocarcinoma

Epidemiological data from the last years show an increasing trend of incidence and mortality of cholangiocarcinoma (CC) worldwide. Many pathophysiologic aspects of this neoplasia are still unknown and need to be fully discovered. However, several progresses were recently made in order to establish the molecular mechanisms involved in the transformation and growth of malignant cholangiocytes. The principal concept that at least seems to be established is that cholangiocarcinogenesis is a multistep cellular process evolving from a normal condition of the epithelial biliary cells through a chronic inflammation status ending with malignant transformation. The bad prognosis related to CC justifies why a better identification of the molecular mechanisms involved in the growth and progression of this cancer is required for the development of effective preventive measures and valid treatment regimens. This Paper describes the scientific progresses made in the last years in defining the molecular pathways implicated in the generation of this devastating disease.

Advances in the treatment of metastatic or unresectable biliary tract cancer

The prognosis for advanced/inoperable biliary tract cancer is poor and the management of biliary obstruction and sepsis remains the cornerstone of best supportive care (BSC). Many phase II studies have reported some activity of chemotherapy, usually involving one or more of a fluoropyrimidine, a platinum agent and gemcitabine. No adequately powered study has shown conclusively a benefit for chemotherapy compared with BSC alone although three small randomized studies have suggested an improved survival. Results from the randomized phase III ABC-02 study demonstrated a survival advantage of cisplatin and gemcitabine doublet-chemotherapy over gemcitabine monotherapy {median survival of 11.7 compared with 8.1 months, hazard ratio (HR), 0.64 [95% confidence interval (CI) 0.52 to 0.80]; log rank P < 0.001} as well as a significantly longer progression-free survival [median 8 compared with 5 months; HR 0.63 (95% CI 0.51 to 0.77); log rank P < 0.001]. A similar magnitude of benefit was seen in Japanese patients in a second study using the same treatment regimens (the BT-22 study). Ongoing studies are underway evaluating other chemotherapy regimens in first-line although attention is turning to the addition of targeted therapies; these will be reviewed. Pivotal to success in this process is both the identification of appropriate targets across this heterogeneous group of malignancies (e.g. EGFR, VEGF, MEK inhibition, amongst others) and collaboration between investigators to deliver relevant, timely and adequately powered studies.

Increased ACE in extrahepatic cholangiocarcinoma as a clue for activated RAS in biliary neoplasms

AIM

Cholangiocarcinoma (CCA) is a primary neoplastic tumor of the epithelial lining of the biliary tree which carries a poor prognosis despite combined therapeutic strategies. Although the exact etiology remains obscure, it has been suggested that locally produced Angiotensin II (Ang II) in intrahepatic CCA tissues plays a key role in the proliferation and activation of CCA. In the present study, we aimed to analyze the relationship between the levels of circulating angiotensin converting enzyme (ACE), an important molecule of the renin-angiotensin system (RAS), and biliary disorders.

PATIENTS AND METHODS

The study group comprised 19 extrahepatic cholangiocarcinoma (EHCC) (16 patients with hilar, three patients with distal CCA), and 15 choledocolithiasis (CL) patients, with 15 controls. Median age of EHCC, CL and healthy controls were 67 (48-82), 65 (29-87) and 56 (23-74) respectively. ACE was measured by monitoring the alteration in absorbance at 340 nm of the hydrolysis of furylacrylolylphenylalanylglycylglycine (FAPGG) to FAP and GG on an analyzer. The ACE activity in the sample was determined by comparing the sample reaction rate to that obtained with the ACE calibrator.

RESULTS

Serum mean ACE levels were 56.6±27.4 U/L, 32.9±14.6 U/L and 28.6±10.6 U/L for patients with EHCC, CL and healthy controls, respectively. Serum ACE levels were significantly higher in patients with EHCC compared to CL and control groups. No significant differences with respect to ACE levels were observed between CL and control groups.

CONCLUSION

Circulating ACE in the context of RAS might be associated with EHCC development by creating a local environment enriched with cytokines and other growth factors that may promote cholangiocyte turnover.

Tamoxifen enhances therapeutic effects of gemcitabine on cholangiocarcinoma tumorigenesis

Cholangiocarcinoma is a highly malignant tumor with limited therapeutic options. We have previously reported that tamoxifen (TMX) induces apoptosis of cholangiocarcinoma cells and reduces cholangiocarcinoma tumorigenesis in mice. In the present studies, we determined the effect of combination therapy of TMX and gemcitabine (GMT), another chemotherapeutical reagent for many cancers, on cholangiocarcinoma tumorigenesis and investigated the responsible mechanisms. GMT inhibited cell growth and induced apoptosis of cholangiocarcinoma cells in a concentration-dependent manner. TMX enhanced GMT-induced apoptosis of cholangiocarcinoma cells. Consistently, GMT (15 mg/kg) inhibited cholangiocarcinoma tumorigenesis in nude mice by 50%. TMX (15 mg/kg) enhanced the inhibitory effect of GMT on tumorigenesis by 33%. The inhibition of tumor growth correlated with enhanced apoptosis in tumor tissues. To elucidate the mechanisms underlying the additive effects of TMX on GMT-induced apoptosis, we determined the activation of caspases in cholangiocarcinoma cells exposed to GMT, TMX, or both. Activation of caspases 9 and 3, as well as cytochrome c release to the cytosol, was demonstrated in cells exposed to both reagents. In contrast, TMX activated caspase 2, whereas GMT had no effect. Inhibition of caspase 2 activation decreased TMX-, but not GMT-, induced activation of caspase 3 and apoptosis of cholangiocarcinoma cells. Similarly, activation of caspase 2 was found in tumors from TMX-treated mice, but not GMT-treated mice. Therefore, the enhanced effect of TMX on GMT-induced cholangiocarcinoma cell death is partially mediated by activation of caspase 2. TMX and GMT both induce apoptosis and inhibit cholangiocarcinoma tumorigenesis, which may be attributed to the activation of distinct apoptosis signals by TMX and GMT. Our studies provide in vivo evidence and molecular insight to support the use of TMX and GMT in combination as an effective therapy for cholangiocarcinoma.

Development of molecularly targeted therapies in biliary tract cancers: reassessing the challenges and opportunities

Biliary tract cancers (BTCs), which encompass intra- and extrahepatic cholangiocarcinomas as well as gallbladder carcinomas, are a genetically diverse collection of cancers. Most patients with BTC will present with unresectable or metastatic disease. Although the standard systemic chemotherapy approaches are emerging, the prognosis remains poor. Development of molecularly targeted therapies in advanced BTC remains challenging. Recent early-stage clinical trials with targeted therapies appear promising, although the relationships between subsets of patients with positive responses to therapy and tumor genetics remain unexplored. Here we summarize the relevant molecular pathogenesis, recent and ongoing clinical trials with targeted agents, and the key issues in clinical trial design in BTC.

Prostate apoptosis response-4 is expressed in normal cholangiocytes, is down-regulated in human cholangiocarcinoma, and promotes apoptosis of neoplastic cholangiocytes when induced pharmacologically

Prostate apoptosis response-4 (Par-4) is a tumor suppressor protein that sensitizes cells to apoptosis; therefore, Par-4 modulation has therapeutic potential. No data currently exist on Par-4 expression in cholangiocarcinoma (CCA). We evaluated the expression of Par-4 in normal and neoplastic cholangiocytes and the effects of its pharmacological or genetic modulation. The study was performed in human and rat liver, CCA patient biopsies, and two CCA cell lines. PAR-4 was expressed in normal rat and human cholangiocytes, but its expression levels decreased in both human CCA and CCA cell lines. In both intrahepatic and extrahepatic CCA, Par-4 expression (as shown by immunohistochemistry) was inversely correlated with markers of proliferation (eg, proliferating cellular nuclear antigen) and directly correlated with apoptotic markers (eg, Bax and Bax/BCL2 ratio). Par-4 expression was decreased during CCA cell proliferation but was enhanced after apoptosis induction. Pharmacological induction of Par-4 expression in CCA cell lines by diindolymethane or withaferin A promoted activation of apoptosis and inhibition of proliferation. In contrast, specific Par-4 silencing by small-interfering RNA determined activation of CCA cell line proliferation. Par-4 is expressed in rat and human cholangiocytes and is down-regulated in both human CCA and CCA cell lines. Par-4 protein levels decrease during cell proliferation but increase during apoptosis. Pharmacological or genetic induction of Par-4 determines apoptosis of CCA cells, suggesting Par-4 targeting as a CCA treatment strategy.

Genetics of biliary tract cancers and emerging targeted therapies

Biliary tract cancers (BTC), which encompass intra- and extrahepatic cholangiocarcinomas and gallbladder carcinomas, are a genetically diverse collection of cancers. Evidence suggests distinct models of molecular and pathologic progression, and a growing body of genetics data points to a heterogeneous collection of underlying mutations in key oncogenes and tumor suppressor genes. Although tumor genetics have been used to tailor individual treatment regimens and guide clinical decision making in other cancers, these principles have not been applied in BTC. Recent clinical trials with targeted therapies seem promising, although the relationships between subsets of patients with positive responses to therapy and tumor genetics remain unexplored. Here, we summarize the molecular pathogenesis and genetics of BTCs and animal modeling and relate these to recent and ongoing clinical trials with targeted agents.

Expression of growth factor receptors and targeting of EGFR in cholangiocarcinoma cell lines

Background

Cholangiocarcinoma (CC) is a malignant neoplasm of the bile ducts or the gallbladder. Targeting of growth factor receptors showed therapeutic potential in palliative settings for many solid tumors. The aim of this study was to determine the expression of seven growth factor receptors in CC cell lines and to assess the effect of blocking the EGFR receptor in vitro.

Methods

Expression of EGFR (epithelial growth factor receptor), HGFR (hepatocyte growth factor receptor) IGF1R (insulin-like growth factor 1 receptor), IGF2R (insulin-like growth factor 2 receptor) and VEGFR1-3 (vascular endothelial growth factor receptor 1-3) were examined in four human CC cell lines (EGI-1, HuH28, OZ and TFK-1). The effect of the anti-EGFR-antibody cetuximab on cell growth and apoptosis was studied and cell lines were examined for KRAS mutations.

Results

EGFR, HGFR and IGFR1 were present in all four cell lines tested. IGFR2 expression was confirmed in EGI-1 and TFK-1. No growth-inhibitory effect was found in EGI-1 cells after incubation with cetuximab. Cetuximab dose-dependently inhibited growth in TFK-1. Increased apoptosis was only seen in TFK-1 cells at the highest cetuximab dose tested (1 mg/ml), with no dose-response-relationship at lower concentrations. In EGI-1 a heterozygous KRAS mutation was found in codon 12 (c.35G>A; p.G12D). HuH28, OZ and TFK-1 lacked KRAS mutation.

Conclusion

CC cell lines express a pattern of different growth receptors in vitro. Growth factor inhibitor treatment could be affected from the KRAS genotype in CC. The expression of EGFR itself does not allow prognoses on growth inhibition by cetuximab.

Molecular mechanisms of cholangiocarcinoma

Cholangiocarcinoma (CC), the malignant tumor of the epithelial cells lining the biliary ducts, has undergone a worldwide increase in incidence and mortality. The malignant transformation of the biliary cells originates from a multistep process evolving through chronic inflammation of the biliary tract to CC. In the last few years several advances have been towards understanding and clarifying the molecular mechanisms implicated in the cholangiocarcinogenesis process. However, many pathophysiologic aspects governing the growth of CC are still undefined. The poor prognosis of this tumor underlines the urgent need to codify the underlying molecular mechanisms involved in the growth and progression of CC in order to design effective preventive measures and valid treatment regimens. This review reports on progresses made in the last few years in clarifying the molecular pathways involved in the process of cholangiocarcinogenesis.

New insights on cholangiocarcinoma

Cholangiocarcinoma (CCA) is a devastating cancer arising from the neoplastic transformation of the biliary epithelium. It is characterized by a progressive increase in incidence and prevalence. The only curative therapy is radical surgery or liver transplantation but, unfortunately, the majority of patients present with advanced stage disease, which is not amenable to surgical therapies. Recently, proposed serum and bile biomarkers could help in the screening and surveillance of categories at risk and in diagnosing CCA at an early stage. The molecular mechanisms triggering neoplastic transformation and growth of biliary epithelium are still undefined, but significant progress has been achieved in the last few years. This review deals with the most recent advances on epidemiology, biology, and clinical management of CCA.

Human cholangiocarcinoma development is associated with dysregulation of opioidergic modulation of cholangiocyte growth

BACKGROUND/AIMS

Incidence of cholangiocarcinoma is increasing worldwide, yet remaining highly aggressive and with poor prognosis. The mechanisms that drive cholangiocyte transition towards malignant phenotype are obscure. Cholangiocyte benign proliferation is subjected to a self-limiting mechanism based on the autocrine release of endogenous opioid peptides. Despite the presence of both, ligands interact with delta opioid receptor (OR), but not with microOR, with the consequent inhibition of cell growth. We aimed to verify whether cholangiocarcinoma growth is associated with failure of opioidergic regulation of growth control.

METHODS

We evaluated the effects of OR selective agonists on cholangiocarcinoma cell proliferation, migration and apoptosis. Intracellular signals were also characterised.

RESULTS

Activation of microOR, but not deltaOR, increases cholangiocarcinoma cell growth. Such an effect is mediated by ERK1/2, PI3K and Ca(2+)-CamKIIalpha cascades, but not by cAMP/PKA and PKCalpha. microOR activation also enhances cholangiocarcinoma cell migration and reduces death by apoptosis. The anti-apoptotic effect of microOR was PI3K dependent.

CONCLUSIONS

Our data indicate that cholangiocarcinoma growth is associated with altered opioidergic regulation of cholangiocyte biology, thus opening new scenarios for future surveillance or early diagnostic strategies for cholangiocarcinoma.

Control of cholangiocyte adaptive responses by visceral hormones and neuropeptides

Cholangiocytes, the epithelial cells lining the biliary tree, are the target cells in several liver diseases, termed cholangiopathies. Cholangiopathies are a challenge for clinicians and an enigma for scientists, as the pathogenetic mechanisms by which they develop, and the therapeutic tools for these diseases are still undefined. Several studies demonstrate that many visceral hormones, neuropeptides, and neurotransmitters modulate the adaptive changes of cholangiocytes to chronic cholestatic injury. The aim of this review is to present the recent findings that contributed to clarify the role of visceral hormones and neuropeptides in the regulation of the pathophysiology of cholestasis. These studies helped to shed light on some aspects of cholangiocyte pathophysiology, revealing novel perspectives for the clinical managements of cholangiopathies.

Role of ErbB family receptor tyrosine kinases in intrahepatic cholangiocarcinoma

Aberrant expression and signaling of epidermal growth factor receptor (ErbB) family receptor tyrosine kinases, most notably that of ErbB2 and ErbB1, have been implicated in the molecular pathogenesis of intrahepatic cholangiocarcinoma. Constitutive overexpression of ErbB2 and/or ErbB1 in malignant cholangiocytes has raised interest in the possibility that agents which selectively target these receptors could potentially be effective in cholangiocarcinoma therapy. However, current experience with such ErbB-directed therapies have at best produced only modest responses in patients with biliary tract cancers. This review provides a comprehensive and critical analysis of both preclinical and clinical studies aimed at assessing the role of altered ErbB2 and/or ErbB1 expression, genetic modifications, and dysregulated signaling on cholangiocarcinoma development and progression. Specific limitations in experimental approaches that have been used to assess human cholangiocarcinoma specimens for ErbB2 and/or ErbB1 overexpression and gene amplification are discussed. In addition, current rodent models of intrahepatic cholangiocarcinogenesis associated with constitutive ErbB2 overexpression are reviewed. Select interactive relationships between ErbB2 or ErbB1 with other relevant molecular signaling pathways associated with intrahepatic cholangiocarcinoma development and progression are also detailed, including those linking ErbB receptors to bile acid, cyclooxygenase-2, interleukin-6/gp130, transmembrane mucins, hepatocyte growth factor/Met, and vascular endothelial growth factor signaling. Lastly, various factors that can limit therapeutic efficacy of ErbB-targeted agents against cholangiocarcinoma are considered.

Photodynamic therapy for non-resectable perihilar cholangiocarcinoma

Photodynamic therapy (PDT) has emerged as a useful tool for palliative treatment of the otherwise difficult to treat perihilar cholangiocarcinoma (CC). PDT is a minimally invasive and effective technique for local tumour ablation with rare and predictable side effects. A modest number of studies and randomised trials using porfimer (Photofrin) could demonstrate an improvement in quality of life and survival time. A novel approach to a priori non-resectable perihilar CC was proven in a pilot study using neoadjuvant porfimer-PDT for down-sizing of the tumour followed by R0 resection. These days, active phase II and phase III trials investigate if the tumouricidal activity can be increased using temoporfin (Foscan) as an alternative photosensitiser with higher penetration capability and whether porfimer-based PDT plus stenting is superior to biliary stenting alone in terms of overall survival, respectively. The local tumour ablation and correction of obstructive cholestasis with PDT will allow for novel multimodal strategies to treat cholangiocarcinoma.