Molecular pathogenesis of cholangiocarcinoma

PTEN deficiency induces an extrahepatic cholangitis-cholangiocarcinoma continuum via aurora kinase A in mice

BACKGROUND & AIMS

The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aimed to evaluate the role of PTEN in the pathogenesis of eCCA and identify novel therapeutic targets for this disease.

METHODS

The Pten gene was genetically deleted using the Cre-loxp system in biliary epithelial cells. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry, reverse-transcription PCR, cell culture, and RNA sequencing. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. We also tested the effectiveness of an Aurka inhibitor.

RESULTS

We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as 1 month after birth. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated disease progression, potentially by downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expression of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression.

CONCLUSIONS

Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum that was dependent on Aurka. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA.

IMPACT AND IMPLICATIONS

The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition, cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted disease progression. This model will be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Impact of Aberrant β-Catenin Pathway on Cholangiocarcinoma Heterogeneity

The poor prognosis of most cases of advanced cholangiocarcinoma (CCA) constitutes a severe problem in modern oncology, which is aggravated by the fact that the incidence of this liver cancer is increasing worldwide and is often diagnosed late, when surgical removal is not feasible. The difficulty of dealing with this deadly tumor is augmented by the heterogeneity of CCA subtypes and the complexity of mechanisms involved in enhanced proliferation, apoptosis avoidance, chemoresistance, invasiveness, and metastasis that characterize CCA. Among the regulatory processes implicated in developing these malignant traits, the Wnt/β-catenin pathway plays a pivotal role. Alteration of β-catenin expression and subcellular localization has been associated with worse outcomes in some CCA subtypes. This heterogeneity, which also affects cellular and in vivo models commonly used to study CCA biology and anticancer drug development, must be taken into account for CCA investigation to more accurately extrapolate basic laboratory research to the clinical situation. A better understanding of the altered Wnt/β-catenin pathway in relationship with the heterogeneous forms of CCA is mandatory for developing novel diagnostic tools and therapeutic strategies for patients suffering from this lethal disease.

Flower-like Composite Material Delivery of Co-Packaged Lenvatinib and Bufalin Prevents the Migration and Invasion of Cholangiocarcinoma

The co-delivery of multiple drugs using nanocarriers has been recognized as a promising strategy for cancer treatment to enhance therapeutic efficacy. In this study, a monodisperse mesoporous silica nanoparticle (mSiO₂) is prepared and functionalized into high-efficiency loaded Lenvatinib and Bufalin for targeted delivery to Cholangiocarcinoma (CCA). mSiO₂ was synthesized on solid silica nanoparticles by oil–water interface method, and highly monodisperse mSiO₂ with uniform morphology was obtained. mSiO₂ was then sequentially modified by polyethylene glycol (PEG) and the targeting molecule folic acid (FA). mSiO₂-FA was designed as co-delivery system for Lenvatinib (Le) and Bufalin (Bu) to increase drug availability and highly target tumor cells. Compared with unfunctionalized mSiO₂, mSiO₂-FA can more efficiently enter human CCA cell lines (9810 cells) and enhance intracellular drug delivery. Moreover, drug-loaded mSiO₂-FA (Le/Bu@mSiO₂-FA) significantly inhibited the viability, migration and invasion of 9810 cells. In vivo, the nanocomplex significantly reduced the tumor load in CCA tumor-bearing mouse models compared to Le or Bu alone. The current work provides a useful strategy for highly targeted and multidrug-resistance reversal therapy for CCA.

Tumor Lymphatic Interactions Induce CXCR2-CXCL5 Axis and Alter Cellular Metabolism and Lymphangiogenic Pathways to Promote Cholangiocarcinoma

Cholangiocarcinoma (CCA), or cancer of bile duct epithelial cells, is a very aggressive malignancy characterized by early lymphangiogenesis in the tumor microenvironment (TME) and lymph node (LN) metastasis which correlate with adverse patient outcome. However, the specific roles of lymphatic endothelial cells (LECs) that promote LN metastasis remains unexplored. Here we aimed to identify the dynamic molecular crosstalk between LECs and CCA cells that activate tumor-promoting pathways and enhances lymphangiogenic mechanisms. Our studies show that inflamed LECs produced high levels of chemokine CXCL5 that signals through its receptor CXCR2 on CCA cells. The CXCR2-CXCL5 signaling axis in turn activates EMT (epithelial-mesenchymal transition) inducing MMP (matrix metalloproteinase) genes such as GLI, PTCHD, and MMP2 in CCA cells that promote CCA migration and invasion. Further, rate of mitochondrial respiration and glycolysis of CCA cells was significantly upregulated by inflamed LECs and CXCL5 activation, indicating metabolic reprogramming. CXCL5 also induced lactate production, glucose uptake, and mitoROS. CXCL5 also induced LEC tube formation and increased metabolic gene expression in LECs. In vivo studies using CCA orthotopic models confirmed several of these mechanisms. Our data points to a key finding that LECs upregulate critical tumor-promoting pathways in CCA via CXCR2-CXCL5 axis, which further augments CCA metastasis.

Hepatobiliary morbidities detected by ultrasonography in Opisthorchis viverrini-infected patients before and after praziquantel treatment: a five-year follow up study

Infection of the liver fluke, Opisthorchis viverrini (OV) is an important public health problem in northeast Thailand and adjacent countries, where people have a habit of eating raw or undercooked fish. A community case-control study was carried out with 8,936 participants from 89 villages, in Khon Kaen province, Thailand. There were 3,359 OV-infected participants all of whom underwent ultrasonography of upper abdomen for the evaluation of hepatobiliary morbidity. The participants with advanced periductal fibrosis (APF) by ultrasound (n = 785) were invited to undergo annual follow-up ultrasonography for five years after praziquantel treatment. The sonographer was blinded with respect to status of OV infection at each visit. The study findings revealed variability in the study population profile of the hepatobiliary morbidities before and after praziquantel treatment over the follow up interval. At the end of the study, 32 (30.8%) out of 104 participants showed no relapse of APF whereas, by contrast, 39 (37.5%) participants showed relapse or persistent APF since the outset of the study (≥ two consecutive visits). The APF in most follow-up visits was significantly associated with male sex, with intrahepatic duct stones, with the width of the gallbladder "pre" minus "post" fatty meal, and with the ratio of left lobe of the liver to aorta. Five cases of suspected cholangiocarcinoma were observed over the five years of follow-up. This long-term ultrasound follow-up study demonstrates a significant incidence of persistent APF in over one-third of opisthorchiasis cases after praziquantel treatment, findings that support the prospect of ongoing cholangiocarcinogenesis long after successful elimination of liver fluke infection among the population.

Tumor Type Agnostic Therapy Carrying BRAF Mutation: Case Reports and Review of Literature

BACKGROUND

Precision medicine is based on molecular and genotypic patient characterization to define specific target treatment. BRAF mutation is an oncogenic driver, and the Cancer Genome Atlas has identified BRAF mutations in different cancer types. Tumor type agnostic therapy is based on targeting genomic alterations, regardless of tumor origin. In this context, novel therapeutic agents including BRAF and MEK inhibitors based on the molecular landscape in solid tumors have been investigated. Case presentation, Case 1: The first case is chemotherapy-refractory, BRAF V600E mutated intrahepaticcholangiocarcinoma treated with vemurafenib and cobimetinib as third line therapy. In this setting the dual BRAF and MEK inhibition resulted in improved progression-free survival and quality of life; Case 2: The second case shows aBRAF G466A mutated Bellini duct carcinoma (BDC), treated with dabrafenib and trametinib in second line therapy. The disease remained under control for 11 months after the first relapse.

DISCUSSION

In the literature there is strong evidence that melanoma, colorectal cancer, non small cell lung cancer and anaplastic thyroid cancer with BRAF mutations are good targets for BRAF/MEK pathway inhibitors. The VE-BASKET and ROAR basket trials explored the efficacy of vemurafenib and the combination of dabrafenib/trametinib, respectively, in BRAF V600 mutation-positive cancers other than melanoma, papillary thyroid cancer, colorectal cancer and non small cell lung cancer. Within the concept of tumor type agnostic therapy, we decided to treat our BRAF-mutated tumors with the association of BRAF and MEK inhibitors.

CONCLUSIONS

Our results confirm the emerging importance of molecular tumor profiling for the successful management of cancer, and the potential of BRAF-targeted therapy in the treatment of rare solid tumors with poor prognosis and no clinical benefit from systemic therapies with.

MC-LR-induced interaction between M2 macrophage and biliary epithelial cell promotes biliary epithelial cell proliferation and migration through regulating STAT3

Microcystin-leucine-arginine (MC-LR) was produced by toxic cyanobacteria, which has been shown to have potent hepatotoxicity. Our previous study has proved that MC-LR were able to promote intrahepatic biliary epithelial cell excessive proliferation. However, the underlying mechanism is not yet entirely clarified. Herein, mice were fed with different concentrations (1, 7.5, 15, or 30 μg/L) of MC-LR by drinking water for 6 months. As the concentration of MC-LR increased, a growing number of macrophages were evaluated in the portal area of the mouse liver. Next, we built a co-culture system to explore the interaction between macrophages (THP-1 cells) and human intrahepatic biliary epithelial cells (HiBECs) in the presence of MC-LR. Under the exposure of MC-LR, HiBECs secreted a large amount of inflammatory factors (IL-6, IL-8, IL-1β, COX-2, XCL-1) and chemokine (MCP-1), which produced a huge chemotactic effect on THP-1 cells and induced elevation of the surface M2-subtype biomarkers (IL-10, CD163, CCL22, and Arg-1). In turn, high content of IL-6 in the medium activated JAK2/STAT3, MEK/ERK, and PI3K/AKT pathways in HiBECs, inducing HiBEC abnormal proliferation and migration. Together, these results suggested that MC-LR-mediated interaction between HiBECs and macrophages induced the M2-type polarization of macrophages, and activated IL-6/JAK2/STAT3, MEK/ERK, and PI3K/AKT pathways in HiBECs, further enhanced cell proliferation, improved cell migration, and hindered cell apoptosis by activating p-STAT3. MC-LR stimulates HiBECs to produce various inflammatory factors, recruiting a large number of macrophages and promoting the differentiation of macrophages into M2-type. In turn, the M2 macrophages could also produce amounts of IL-6 and activate STAT3 through JAK2/STAT3, MEK/ERK, and PI3K/AKT pathways in HiBECs, resulting in the promotion of cell proliferation, inhibition of apoptosis, and enhancement of migration.

The Advancement of Long Non-Coding RNAs in Cholangiocarcinoma Development

Cholangiocarcinoma (CCA) is a malignancy with increasing incidence in recent years. CCA patients are usually diagnosed at advanced stage due to lack of apparent symptoms and specifically diagnostic markers. Nowadays, surgical removal is the only effective method for CCA whereas overall 5-year-survival rate keeps around 10%. Long-noncoding RNA (lncRNA), a subtype of noncoding RNA, is widely studied to be abnormally expressed in multiple cancers including CCA. LncRNA can promote proliferation, migration, invasion and inhibit apoptosis of CCA. Moreover, lncRNA is negatively correlated with the prognosis of CCA. LncRNA may contribute to the development of CCA via modulating gene transcription, sponging microRNA, regulating CCA-related signaling pathways or protein expression. LncRNA is thought to be potential diagnostic markers and therapeutic targets for CCA.

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.

Bioactive constituents isolated from Atractylodes lancea (Thunb.) DC. rhizome exhibit synergistic effect against cholangiocarcinoma cell

Background

Cholangiocarcinoma (CCA) is the primary type of bile duct cancer with high morbidity and mortality, particularly in patients with advanced-stage disease. Treatment of CCA remains unsatisfactory due to the lack of sensitive and specific diagnostic tool for early detection as well as effective chemotherapeutics.

Purpose

To investigate cytotoxic interactions between the three major constituents of the rhizomes of Atractylodes lancea (Thunb.) DC., ie, β-eudesmol (BE), atractylodin (AT), and hinesol (HS), against CCA cell line.

Methods

Cytotoxic activities against the human CCA cells CL-6 of the dual (BE:AT, BE:HS, and AT:HS) and triple (BE:AT:HS) combinations were evaluated using MTT assay. The cytotoxic interaction of each dual combination was assessed at five concentration ratios (10:0, 7:3, 5:5, 3:7, and 0:10) using isobologram analysis. For triple combination, the concentration ratio used in the experiment was 1:1.5:2.5 (BE:AT:HS) and analysis of the interaction was performed using polygonogram analysis at the concentrations that inhibit cell growth by 50% and 90%, respectively.

Results

The BE:AT combination produced the additive effect with sum fractional inhibitory concentration of 0.967±0.02 (mean ± SD). The BE:HS and AT:HS combinations produced a synergistic effect with sum fractional inhibitory concentrations of 0.685±0.08 and 0.767±0.09, respectively. The mixture of the three compounds produced synergistic interaction with combination index values of 0.519±0.10 and 0.65±0.17 (mean ± SD) at the concentrations that inhibit cell growth at the 50% and 90% leveled, respectively.

Conclusion

Results obtained would guide further development of Atractylodes lancea (Thunb.) DC. as potential anti-CCA chemotherapeutics concerning the appropriate pharmaceutical dosage form.

Podoplanin is an important stromal prognostic marker in perihilar cholangiocarcinoma

Cancer-associated fibroblasts (CAFs) exhibit various phenotypes and serve an important role in tumor progression. However, research on podoplanin expression in CAFs is limited, and its role in the cholangiocarcinoma microenvironment remains unclear. The present study analyzed the clinical and pathological records of 42 patients diagnosed with perihilar cholangiocarcinoma (pCCA) in The Affiliated Drum Tower Hospital of Nanjing University Medical School (Nanjing, China). Immunohistochemical staining was performed to evaluate the expression of podoplanin in CAFs in order to determine its association with clinicopathological parameters and survival rate. Podoplanin expression in the CAFs was associated with the tumor-node-metastasis staging system, and lymph node metastasis in pCCA. Tumor tissue demonstrated an increase in lymphatic vessel density (LVD) compared with para-tumor tissue. Podoplanin expression in CAFs was associated with LVD in tumor and para-tumor tissues. To examine the effect of podoplanin expression in CAFs on tumor progression, CAFs were isolated from tumor xenografts. Following transfection with an expression plasmid encoding podoplanin, the migratory ability of CAFs was significantly increased. Therefore, CAF-associated podoplanin expression in pCCA may serve as a potential biomarker to evaluate prognosis and provide a valuable target for anticancer therapy.

Large numbers of interleukins-22- and -17A-producing T helper cells in cholangiocarcinoma related to liver fluke infection

Cholangiocarcinoma (CCA) associated with liver fluke infection involves inflammatory and immune processes; however, whether these involve the proinflammatory cytokine IL-17A and proliferative cytokine IL-22 remains unclear. Here, numbers of IL-22- and IL-17A-producing Th cells and cytokine concentrations in 30 patients with CCA and long-term liver fluke infection, 40 patients with liver-fluke infection but not CCA, and 16 healthy controls were compared. Analyses were performed using immunohistochemistry, flow cytometry, ELISA and RT-PCR. Immunohistochemical staining showed weaker expression of IL-22 and IL-17A in patients with CCA with than in those without liver fluke infection (P < 0.01). Flow cytometry revealed significantly greater median proportions of IL-22-producing T helper cells in patients with CCA (2.2%) than in those without it (0.69%) or controls (0.4%, P < 0.001). Similar results were obtained for IL-17A-producing T helper cells. ELISA revealed plasma concentrations of IL-22 were 1.3-fold higher in patients with CCA than in those without it and 4.6-fold higher than in controls (P < 0.001). Plasma concentrations of IL-17A were 2.5-fold higher in patients with CCA than in those without it, and 21-fold higher than in controls (P < 0.001). Amounts of IL-22 and IL-17A mRNAs in blood were significantly higher in patients with CCA than in the other two groups. Proportions of CD4+ CD45RO+ T cells producing IL-22 correlated with proportions producing IL-17A (r = 0.759; P < 0.001), and plasma concentrations of IL-22 correlated with those of IL-17A (r = 0.726; P < 0.001). These results suggest that both IL-17A and IL-22 affect development of CCA related to liver fluke infection.

Micro-RNA-130a-3p Regulates Gemcitabine Resistance via PPARG in Cholangiocarcinoma

BACKGROUND

The prognosis of cholangiocarcinoma (CCA) is so poor that its chemoresistance needs to be reduced. In this study, we focused on the microRNAs (miRNAs) associated with gemcitabine resistance of CCA and assessed the clinical significance of miRNAs and their target genes.

METHODS

We performed miRNA microarray analysis for two CCA cell lines (CCLP-1 and MzChA-1) and their gemcitabine-resistant (GR) cells. An miR-130a-3p mimic was induced into CCA cells using lipofection, and we used pioglitazone as a peroxisome proliferator-activated receptor-γ (PPARγ) agonist in vitro. The expression of miR-130a-3p was studied in 27 intrahepatic CCA samples after laser capture microdissection (LCM) and by immunohistochemistry from patients who had undergone curative resection from March 2004 to November 2012 at Osaka University Hospital.

RESULTS

miR-130a-3p expression was upregulated in CCLP-1-GRs and MzChA-1-GRs significantly more than in their parental cells. Transfection of the miR-130a-3p mimic into CCA cells increased gemcitabine resistance, and we detected PPARG as a target gene of miR-130a-3p. Furthermore, pioglitazone had a synergistic effect with gemcitabine and alleviated gemcitabine resistance of CCA GR cells. Moreover, clinical examination revealed that for patients who underwent adjuvant gemcitabine therapy, those who were PPARγ positive had significantly longer disease-free survival than those who were PPARγ negative (n = 5 and 11, respectively; p = 0.027).

CONCLUSIONS

Our data suggest that miR-130a-3p was associated with gemcitabine resistance in CCA through PPARG, and there is a possibility that pioglitazone can be used for the treatment of CCA.

miR-106b regulates the 5-fluorouracil resistance by targeting Zbtb7a in cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is highly resistant to chemo-therapy, including 5-fluorouracil (5-FU) treatment. MicroRNAs are endogenous and short non-coding RNAs that can regulate multiple genes expression. Many microRNAs have shown functional roles in the chemo-resistance of tumors. Here, we examined the relationship between microRNAs expression and the sensitivity of CCA cells to 5-FU.

Methods

Microarray analysis was used to determine the aberrantly expressed microRNAs in two 5-FU resistant CCA cell lines, KKU-M139 and KKU-M214 cells. To determine the effect of candidate microRNAs on 5-FU sensitivity, expression of candidate was modified via either transfection of a microRNA mimic or transfection of an antagonist. Ontology-based programs were also used to investigate the potential targets of microRNAs that were confirmed to affect the 5-FU sensitivity of CCA cells.

Results

The microRNA-106b (miR-106b) was significantly down-regulated in 5-FU resistant CCA cells. Instead, over-expression of miR-106b could re-sensitize resistant CCA cells to 5-FU through down-regulation of Zbtb7a. Moreover, decreased expression of miR-106b is related to poor prognosis in patients with CCA, suggesting its potential role as a new prognostic marker in CCA.

Conclusion

Our study demonstrates that miR-106b can reverse 5-FU resistance via Zbtb7a suppression, thus offer a novel and powerful strategy for CCA chemotherapy.

Jagged 1 is a major Notch ligand along cholangiocarcinoma development in mice and humans

Intrahepatic cholangiocarcinoma (ICC) is a rare yet deadly malignancy with limited treatment options. Activation of the Notch signalling cascade has been implicated in cholangiocarcinogenesis. However, while several studies focused on the Notch receptors required for ICC development, little is known about the upstream inducers responsible for their activation. Here, we show that the Jagged 1 (Jag1) ligand is almost ubiquitously upregulated in human ICC samples when compared with corresponding non-tumorous counterparts. Furthermore, we found that while overexpression of Jag1 alone does not lead to liver tumour development, overexpression of Jag1 synergizes with activated AKT signalling to promote liver carcinogenesis in AKT/Jag1 mice. Histologically, tumours consisted exclusively of ICC, with hepatocellular tumours not occurring in AKT/Jag1 mice. Furthermore, tumours from AKT/Jag1 mice exhibited extensive desmoplastic reaction, an important feature of human ICC. At the molecular level, we found that both AKT/mTOR and Notch cascades are activated in AKT/Jag1 ICC tissues, and that the Notch signalling is necessary for ICC development in AKT/Jag1 mice. In human ICC cell lines, silencing of Jag1 via specific small interfering RNA reduces proliferation and increases apoptosis. Finally, combined inhibition of AKT and Notch pathways is highly detrimental for the in vitro growth of ICC cell lines. In summary, our study demonstrates that Jag1 is an important upstream inducer of the Notch signalling in human and mouse ICC. Targeting Jag1 might represent a novel therapeutic strategy for the treatment of this deadly disease.

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.

Taurocholate Induces Cyclooxygenase-2 Expression via the Sphingosine 1-phosphate Receptor 2 in a Human Cholangiocarcinoma Cell Line

Cholangiocarcinoma (CCA) is a rare, but highly malignant primary hepatobiliary cancer with a very poor prognosis and limited treatment options. Our recent studies reported that conjugated bile acids (CBAs) promote the invasive growth of CCA via activation of sphingosine 1-phosphate receptor 2 (S1PR2). Cyclooxygenase-2 (COX-2)-derived prostaglandin E2 (PGE2) is the most abundant prostaglandin in various human malignancies including CCA. Previous studies have indicated that COX-2 was highly expressed in CCA tissues, and the survival rate of CCA patients was negatively associated with high COX-2 expression levels. It has also been reported that CBAs induce COX-2 expression, whereas free bile acids inhibit COX-2 expression in CCA mouse models. However, the underlying cellular mechanisms and connection between S1PR2 and COX-2 expression in CCA cells have still not been fully elucidated. In the current study, we examined the role of S1PR2 in conjugated bile acid (taurocholate, (TCA))-induced COX-2 expression in a human HuCCT1 CCA cell line and further identified the potential underlying cellular mechanisms. The results indicated that TCA-induced invasive growth of human CCA cells was correlated with S1PR2-medated up-regulation of COX-2 expression and PGE2 production. Inhibition of S1PR2 activation with chemical antagonist (JTE-013) or down-regulation of S1PR2 expression with gene-specific shRNA not only reduced COX-2 expression, but also inhibited TCA-induced activation of EGFR and the ERK1/2/Akt-NF-κB signaling cascade. In conclusion, S1PR2 plays a critical role in TCA-induced COX-2 expression and CCA growth and may represent a novel therapeutic target for CCA.

Prognostic Impact of Peritumoral IL-17-Positive Cells and IL-17 Axis in Patients with Intrahepatic Cholangiocarcinoma

BACKGROUND

Development of cancer has been linked to inflammatory cytokines such as interleukin (IL)-6 and IL-17. In this study, we assessed the expression of these cytokines in intrahepatic cholangiocarcinoma (ICC) and determined their correlation to the survival probability.

METHODS

A total of 72 consecutive patients who underwent curative resection of ICC at Osaka University Hospital from March 1998 to November 2014 were enrolled. Immunohistochemical analysis was performed for IL-17 and its receptor A (IL-17RA), as well as IL-6. Enzyme-linked immunosorbent assay (ELISA) was performed for preoperative plasma levels of IL-6 and IL-17 in 32 patients with ICC.

RESULTS

Immunohistochemical analysis showed that the IL-6(high) (n = 34) and IL-17RA(high) (n = 29) groups had significantly worse disease-free survival (DFS) than IL-6(low) (n = 38) and IL-17RA(low) (n = 43) groups, respectively. Although IL-17(+) cells were abundant in the intratumoral area, patients with high peritumoral, but not intratumoral, IL-17(+) cells (n = 28) corresponded with a significantly lower overall survival (OS) and DFS (OS, p = 0.023; DFS, p = 0.026) than those with low group. Moreover, multivariate Cox proportional hazards analysis revealed that IL-6, peritumoral IL-17(+), and IL-17RA are independent prognostic factors for DFS (p = 0.023, p = 0.0088, p = 0.039, respectively). In addition, high preoperative plasma levels of IL-6 in patients with ICC corresponded with significantly lower DFS (p = 0.002).

CONCLUSIONS

Our data suggested that IL-6, peritumoral IL-17(+) cells, and IL-17RA expression are postoperative useful markers for predicting recurrence in patients with ICC.

Capsaicin Enhances the Drug Sensitivity of Cholangiocarcinoma through the Inhibition of Chemotherapeutic-Induced Autophagy

Cholangiocarcinoma (CCA), a devastating cancer with a poor prognosis, is resistant to the currently available chemotherapeutic agents. Capsaicin, the major pungent ingredient found in hot red chili peppers of the genus Capsicum, suppresses the growth of several malignant cell lines. Our aims were to investigate the role and mechanism of capsaicin with respect to the sensitivity of CCA cells to chemotherapeutic agents. The effect of capsaicin on CCA tumor sensitivity to 5-fluorouracil (5-FU) was assessed in vitro in CCA cells and in vivo in a xenograft model. The drug sensitivity of QBC939 to 5-FU was significantly enhanced by capsaicin compared with either agent alone. In addition, the combination of capsaicin with 5-FU was synergistic, with a combination index (CI) < 1, and the combined treatment also suppressed tumor growth in the CCA xenograft to a greater extent than 5-FU alone. Further investigation revealed that the autophagy induced by 5-FU was inhibited by capsaicin. Moreover, the decrease in AKT and S6 phosphorylation induced by 5-FU was effectively reversed by capsaicin, indicating that capsaicin inhibits 5-FU-induced autophagy by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway in CCA cells. Taken together, these results demonstrate that capsaicin may be a useful adjunct therapy to improve chemosensitivity in CCA. This effect likely occurs via PI3K/AKT/mTOR pathway activation, suggesting a promising strategy for the development of combination drugs for CCA.