Epithelial-mesenchymal transition induced by transforming growth factor-{beta}1/Snail activation aggravates invasive growth of cholangiocarcinoma

Cancer-Associated Fibroblasts in Intrahepatic Cholangiocarcinoma: Insights into Origins, Heterogeneity, Lymphangiogenesis, and Peritoneal Metastasis

Intrahepatic cholangiocarcinoma (iCCA) denotes a rare, highly malignant, and heterogeneous class of primary liver adenocarcinomas exhibiting phenotypic characteristics of cholangiocyte differentiation. Among the distinctive pathological features of iCCA, one that differentiates the most common macroscopic subtype (eg, mass-forming type) of this hepatic tumor from conventional hepatocellular carcinoma is a prominent desmoplastic reaction manifested as a dense fibro-collagenous-enriched tumor stroma. Cancer-associated fibroblasts (CAFs) represent the most abundant mesenchymal cell type in the desmoplastic reaction. Although the protumor effects of CAFs in iCCA have been increasingly recognized, more recent cell lineage tracing studies, advanced single-cell RNA sequencing, and expanded biomarker analyses have provided new awareness into their ontogeny, as well as underscored their biological complexity as reflected by the presence of multiple subtypes. In addition, evidence supports CAFs' potential to display cancer-restrictive roles, including immunosuppression. However, CAFs also play important roles in facilitating metastasis, as exemplified by lymph node metastasis and peritoneal carcinomatosis, which are common in iCCA. Herein, the authors provide a timely appraisal of the origins and phenotypic and functional complexity of CAFs in iCCA, together with providing mechanistic insights into lymphangiogenesis and peritoneal metastasis relevant to this lethal human cancer.

Cross-Talk Between Tumor Cells and Stellate Cells Promotes Oncolytic VSV Activity in Intrahepatic Cholangiocarcinoma

As the mechanisms underlying tumorigenesis become better understood, the dynamic roles of cellular components of the tumor microenvironment, and their cross-talk with tumor cells, have come to light as key drivers of disease progression and have emerged as important targets of new cancer therapies. In the field of oncolytic virus (OV) therapy, stromal cells have been considered as potential barriers to viral spread, thus limiting virus replication and therapeutic outcome. However, new evidence indicates that intratumoral fibroblasts could support virus replication. We have demonstrated in a rat model of stromal-rich intrahepatic cholangiocarcinoma (CCA) that vesicular stomatitis virus (VSV) can be localized within intratumoral hepatic stellate cells (HSCs), in addition to tumor cells, when the virus was applied via hepatic arterial infusion. Furthermore, VSV was shown to efficiently kill CCA cells and activated HSCs, and co-culture of CCA and HSCs increased viral titers. Interestingly, this effect is also observed when each cell type is cultured alone in a conditioned medium of the other cell type, indicating that secreted cell factors are at least partially responsible for this phenomenon. Partial reduction in sensitivity to type I interferons was observed in co-culture systems, providing a possible mechanism for the increased viral titers. Together, the results indicate that targeting activated HSCs with VSV could provide an additional mechanism of OV therapy, which, until now has not been considered. Furthermore, these findings suggest that VSV is a potentially powerful therapeutic agent for stromal-rich tumors, such as CCA and pancreatic cancer, both of which are very difficult to treat with conventional therapy and have a very poor prognosis.

The crosstalk between cholangiocytes and hepatic stellate cells promotes the progression of epithelial-mesenchymal transition and periductal fibrosis during Clonorchis sinensis infection

ABSTRACT: BACKGROUND: Clonorchis sinensis infection is one of the risk factors that provokes chronic inflammation, epithelial hyperplasia, periductal fibrosis and even cholangiocarcinoma (CCA). Disrupted or aberrant intercellular communication among liver-constituting cells leads to pathological states that cause various hepatic diseases. This study was designed to investigate the pathological changes caused by C. sinensis excretory-secretory products (ESPs) in non-cancerous human cell lines (cholangiocytes [H69 cell line] and human hepatic stellate cells [LX2 cell line]) and their intercellular crosstalk, as well the pathological changes in infected mouse liver tissues.

METHODS

The cells were treated with ESPs, following which transforming growth factor beta 1 (TGF-β1) and interleukin-6 (IL-6) secretion levels and epithelial-mesenchymal transition (EMT)- and fibrosis-related protein expression were measured. The ESP-mediated cellular motility (migration/invasion) between two cells was assessed using the Transwell and three-dimensional microfluidic assay models. The livers of C. sinensis-infected mice were stained using EMT and fibrotic marker proteins.

RESULTS

Treatment of cells with ESPs increased TGF-β1 and IL-6 secretion and the expression of EMT- and fibrosis-related proteins. The ESP-mediated mutual cell interaction further affected the cytokine secretion and protein expression levels and promoted cellular motility. N-cadherin overexpression and collagen fiber deposition were observed in the livers of C. sinensis-infected mice.

CONCLUSIONS

These findings suggest that EMT and biliary fibrosis occur through intercellular communication between cholangiocytes and hepatic stellate cells during C. sinensis infection, promoting malignant transformation and advanced hepatobiliary abnormalities.

Mechanisms underlying the changes in acetaldehyde dehydrogenase 1 in cholangiocarcinoma

Cholangiocarcinoma (CCA) is the most recurrent malignant tumor found in the biliary system. It originates from the bile duct epithelial cells characterized by easy metastasis, high intermittent rate, and poor prognosis. Acetaldehyde dehydrogenase 1 (ALDH1), a marker of cancer stem cells, the levels of which are particularly elevated in various of malignant tumors. Additionally, the increased ALDH1 levels are closely related to the degree and prognosis of malignant tumors. This study reviewed the mechanisms underlying the changes in ALDH1 levels in CCA.

The role and implication of autophagy in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a malignant tumor that originates from the biliary epithelial cells. It is characterized by a difficult diagnosis and limited treatment options. Autophagy is a cellular survival mechanism that maintains nutrient and energy homeostasis and eliminates intracellular pathogens. It is involved in various physiological and pathological processes, including the development of cancer. However, the role, mechanism, and potential therapeutic targets of autophagy in CCA have not been thoroughly studied. In this review, we introduce the classification, characteristics, process, and related regulatory genes of autophagy. We summarize the regulation of autophagy on the progression of CCA and collect the latest research progress on some autophagy modulators with clinical potential in CCA. In conclusion, combining autophagy modulators with immunotherapy, chemotherapy, and targeted therapy has great potential in the treatment of CCA. This combination may be a potential therapeutic target for CCA in the future.

Postoperative Prognostic Predictors of Bile Duct Cancers: Clinical Analysis and Immunoassays of Tissue Microarrays

BACKGROUND/AIMS

Cholangiocarcinoma frequently recurs even after curative resection. Expression levels of proteins such as epidermal growth factor receptor (EGFR), Snail, epithelial cadherin (E-cadherin), and interleukin-6 (IL-6) examined by immunohistochemistry have been studied as potential prognostic factors for cholangiocarcinoma. The aim of this study was to investigate significant factors affecting the prognosis of resectable cholangiocarcinoma.

METHODS

Ninety-one patients who underwent surgical resection at Samsung Medical Center for cholangiocarcinoma from 1995 to 2013 were included in this study. Expression levels of E-cadherin, Snail, IL-6, membranous EGFR, and cytoplasmic EGFR were analyzed by immunohistochemistry using tissue microarray blocks made from surgical specimens.

RESULTS

Patients with high levels of membranous EGFR in tissue microarrays had significantly shorter overall survival (OS) and disease-free survival (DFS): high membranous EGFR (score 0-2) 38.0 months versus low membranous EGFR (score 3) 14.4 months (p=0.008) and high membranous EGFR (score 0-2) 23.2 months versus low membranous EGFR (score 3) 6.1 months (p=0.004), respectively. On the other hand, E-cadherin, Snail, cytoplasmic EGFR, and IL-6 did not show significant association with OS or DFS. Patients with distant metastasis had significantly higher IL-6 levels than those with locoregional recurrence (p=0.01).

CONCLUSIONS

This study showed that overexpression of membranous EGFR was significantly associated with shorter OS and DFS in surgically resected bile duct cancer patients. In addition, higher IL-6 expression was a predictive marker for recurrence in cholangiocarcinoma patients with distant organ metastasis after surgical resection.

Review and Application of Integrin Alpha v Beta 6 in the Diagnosis and Treatment of Cholangiocarcinoma and Pancreatic Ductal Adenocarcinoma

Integrin Alpha v Beta 6 is expressed primarily in solid epithelial tumors, such as cholangiocarcinoma, pancreatic cancer, and colorectal cancer. It has been considered a potential and promising molecular marker for the early diagnosis and treatment of cancer. Cholangiocarcinoma and pancreatic ductal adenocarcinoma share genetic, histological, and pathophysiological similarities due to the shared embryonic origin of the bile duct and pancreas. These cancers share numerous clinicopathological characteristics, including growth pattern, poor response to conventional radiotherapy and chemotherapy, and poor prognosis. This review focuses on the role of integrin Alpha v Beta 6 in cancer progression. It addition, it reviews how the marker can be used in molecular imaging and therapeutic targets. We propose further research explorations and questions that need to be addressed. We conclude that integrin Alpha v Beta 6 may serve as a potential biomarker for cancer disease progression and prognosis.

Molecular Subgroups of Intrahepatic Cholangiocarcinoma Discovered by Single-Cell RNA Sequencing-Assisted Multi-Omics Analysis

Intrahepatic cholangiocarcinoma (ICC) is a relatively rare but highly aggressive tumor type that responds poorly to chemotherapy and immunotherapy. Comprehensive molecular characterization of ICC is essential for the development of novel therapeutics. Here, we constructed two independent cohorts from two clinic centers. A comprehensive multi-omics analysis of ICC via proteomic, whole-exome sequencing (WES), and single-cell RNA sequencing (scRNA-seq) was performed. Novel ICC tumor subtypes were derived in the training cohort (n=110) using proteomic signatures and their associated activated pathways, which was further validated in a validation cohort (n=41). Three molecular subtypes, chromatin remodeling, metabolism, and chronic inflammation, with distinct prognoses in ICC were identified. The chronic inflammation subtype associated with a poor prognosis. Our random forest algorithm revealed that mutation of lysine methyltransferase 2D (KMT2D) frequently occurred in the metabolism subtype and associated with lower inflammatory activity. scRNA-seq further identified an APOE+C1QB+ macrophage subtype, which showed the capacity to reshape the chronic inflammation subtype and contribute to a poor prognosis in ICC. Altogether, with single-cell transcriptome-assisted multi-omics analysis, we identified novel molecular subtypes of ICC and validated APOE+C1QB+ tumor-associated macrophages (TAMs) as potential immunotherapy targets against ICC.

Immunotherapy for Biliary Tract Cancer in the Era of Precision Medicine: Current Knowledge and Future Perspectives

Biliary tract cancers (BTC) represent a heterogeneous and aggressive group of tumors with dismal prognosis. For a long time, BTC has been considered an orphan disease with very limited therapeutic options. In recent years a better understanding of the complex molecular landscape of biology is rapidly changing the therapeutic armamentarium. However, while 40-50% of patients there are molecular drivers susceptible to target therapy, for the remaining population new therapeutic options represent an unsatisfied clinical need. The role of immunotherapy in the continuum of treatment of patients with BTC is still debated. Despite initial signs of antitumor-activity, single-agent immune checkpoint inhibitors (ICIs) demonstrated limited efficacy in an unselected population. Therefore, identifying the best partner to combine ICIs and predictive biomarkers represents a key challenge to optimize the efficacy of immunotherapy. This review provides a critical analysis of completed trials, with an eye on future perspectives and possible biomarkers of response.

Role of miR-218-GREM1 axis in epithelial-mesenchymal transition of oral squamous cell carcinoma: An in vivo and vitro study based on microarray data

Oral squamous cell carcinoma (OSCC) is a prevalent cancer that develops in the head and neck area and has high annual mortality despite optimal treatment. microRNA‐218 (miR‐218) is a tumour inhibiting non‐coding RNA that has been reported to suppress the cell proliferation and invasion in various cancers. Thus, our study aims to determine the mechanism underlying the inhibitory role of miR‐218 in OSCC. We conducted a bioinformatics analysis to screen differentially expressed genes in OSCC and their potential upstream miRNAs. After collection of surgical OSCC tissues, we detected GREM1 expression by immunohistochemistry, RT‐qPCR and Western blot analysis, and miR‐218 expression by RT‐qPCR. The target relationship between miR‐218 and GREM1 was assessed by dual‐luciferase reporter gene assay. After loss‐ and gain‐of‐function experiments, OSCC cell proliferation, migration and invasion were determined by MTT assay, scratch test and Transwell assay, respectively. Expression of TGF‐β1, Smad4, p21, E‐cadherin, Vimentin and Snail was measured by RT‐qPCR and Western blot analysis. Finally, effects of miR‐218 and GREM1 on tumour formation and liver metastasis were evaluated in xenograft tumour‐bearing nude mice. GREM1 was up‐regulated, and miR‐218 was down‐regulated in OSCC tissues, and GREM1 was confirmed to be the target gene of miR‐218. Furthermore, after up‐regulating miR‐218 or silencing GREM1, OSCC cell proliferation, migration and invasion were reduced. In addition, expression of TGF‐β signalling pathway‐related genes was diminished by overexpressing miR‐218 or down‐regulating GREM1. Finally, up‐regulated miR‐218 or down‐regulated GREM1 reduced tumour growth and liver metastasis in vivo. Taken together, our findings suggest that the overexpression of miR‐218 may inhibit OSCC progression by inactivating the GREM1‐dependent TGF‐β signalling pathway.

Circulating TGF-β1 as the potential epithelial mesenchymal transition-biomarker for diagnosis of cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is a malignant tumor arising from bile duct epithelium. The oncogenic risk factor is infection by the liver fluke, Opisthorchis viverrini (Ov). One of key mechanism in the development of CCA is epithelial mesenchymal transition (EMT). We aimed to investigate the expression of EMT-related proteins namely, E-cadherin, TGF-β1 and BMP-7 in CCA tissues, to determine the level of candidate EMT-related protein, and to examine whether there were significant correlations with clinicopathological data in sera of CCA patients compared with normal groups.

Methods

The expression of E-cadherin, TGF-β1 and BMP-7 was analyzed in human CCA tissues by immunohistochemistry and altered expressions compared to clinicopathological data were analyzed to identify the potential candidate EMT-biomarker. Subsequently, the level of candidate marker was determined in sera of CCA patients compared with normal and inflammatory-related diseases groups by enzyme-linked immunosorbent assay (ELISA).

Results

Immunohistochemical analysis showed that E-cadherin was expressed at a low level whereas TGF-β1 and BMP-7 showed high expression in CCA tissues when compared with liver from cadaveric donor. Interestingly, only high TGF-β1 expression in CCA tissues was significantly correlated with lymph node metastasis, severe cancer stage, intrahepatic CCA type and shorter survival time of CCA patients (P<0.05). Consequently, TGF-β1 was selected to determine the level in serum of CCA patients using ELISA. The results showed that serum TGF-β1 level was elevated in CCA patients compared to the normal group. Patients with high TGF-β1 levels were significantly correlated with metastasis status (P=0.03). Furthermore, receiver operating characteristic (ROC) analysis showed that serum TGF-β1 level is effective in distinguishing CCA patients from normal at the cut-off of 38.54 ng/mL with high sensitivity (71.1%) and specificity (68.9%) and from inflammatory-related diseases group at the cut-off of 38.67 ng/mL with effective sensitivity (68.0%) and specificity (71.1%). Furthermore, TGF-β1 could serve as a novel metastatic biomarker in CCA to diagnose the disease with 48.95 ng/mL as the cut-off along with the desired sensitivity and specificity (48.2% and 88.9% respectively).

Conclusions

The results of this study show that TGF-β1 could be a potential EMT-biomarker for diagnosis and prognosis of CCA.

Periostin induces epithelial‑to‑mesenchymal transition via the integrin α5β1/TWIST‑2 axis in cholangiocarcinoma

Periostin (PN) (also known as osteoblast-specific factor OSF-2) is a protein that in humans is encoded by the POSTN gene and has been correlated with a reduced survival of cholangiocarcinoma (CCA) patients, with the well-known effect of inducing epithelial-to-mesenchymal transition (EMT). The present study investigated the effect of PN, through integrin (ITG)α5β1, in EMT-mediated CCA aggressiveness. The alterations in EMT-related gene and protein expression were investigated by real-time PCR, western blot analysis and zymogram. The effects of PN on migration and the level of TWIST-2 were assessed in CCA cells with and without siITGα5 transfection. PN was found to induce CCA cell migration and EMT features, including increments in Twist-related protein 2 (TWIST-2), zinc finger protein SNAI1 (SNAIL-1), α-smooth muscle actin (ASMA), vimentin (VIM) and matrix metallopeptidase 9 (MMP-9), and a reduction in cytokeratin 19 (CK-19) together with cytoplasmic translocation of E-cadherin (CDH-1). Additionally, PN markedly induced MMP-9 activity. TWIST-2 was significantly induced in PN-treated CCA cells; this effect was attenuated in the ITGα5β1-knockdown cells and corresponded to reduced migration of the cancer cells. These results indicated that PN induced CCA migration through ITGα5β1/TWIST-2-mediated EMT. Moreover, clinical samples from CCA patients showed that higher levels of TWIST-2 were significantly correlated with shorter survival time. In conclusion, the ITGα5β1-mediated TWIST-2 signaling pathway regulates PN-induced EMT in CCA progression, and TWIST-2 is a prognostic marker of poor survival in CCA patients.

Inflammation and Progression of Cholangiocarcinoma: Role of Angiogenic and Lymphangiogenic Mechanisms

Cholangiocarcinoma (CCA), or cancer of the biliary epithelium is a relatively rare but aggressive form of biliary duct cancer which has a 5-year survival rate post metastasis of 2%. Although a number of risk factors are established for CCA growth and progression, a careful evaluation of the existing literature on CCA reveals that an inflammatory environment near the biliary tree is the most common causal link between the risk factors and the development of CCA. The fact that inflammation predisposes affected individuals to CCA is further bolstered by multiple observations where the presence and maintenance of an inflammatory microenvironment at the site of the primary tumor plays a significant role in the development and metastasis of CCA. In addition, mechanisms activating the tumor vasculature and enhancing angiogenesis and lymphangiogenesis significantly contribute to CCA aggressiveness and metastasis. This review aims to address the role of an inflammatory microenvironment-CCA crosstalk and will present the basic concepts, observations, and current perspectives from recent research studies in the field of tumor stroma of CCA.

Mitogen-Activated Protein Kinases (MAPKs) and Cholangiocarcinoma: The Missing Link

In recent years, the incidence of both liver and biliary tract cancer has increased. Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) are the two most common types of hepatic malignancies. Whereas HCC is the fifth most common malignant tumor in Western countries, the prevalence of CCA has taken an alarming increase from 0.3 to 2.1 cases per 100,000 people. The lack of specific biomarkers makes diagnosis very difficult in the early stages of this fatal cancer. Thus, the prognosis of CCA is dismal and surgery is the only effective treatment, whilst recurrence after resection is common. Even though chemotherapy and radiotherapy may prolong survival in patients with CCA, the 5-year survival rate is still very low-a significant global problem in clinical diagnosis and therapy. The mitogen-activated protein kinase (MAPK) pathway plays an important role in signal transduction by converting extracellular stimuli into a wide range of cellular responses including inflammatory response, stress response, differentiation, survival, and tumorigenesis. Dysregulation of the MAPK cascade involves key signaling components and phosphorylation events that play an important role in tumorigenesis. In this review, we discuss the pathophysiological role of MAPK, current therapeutic options, and the current situation of MAPK-targeted therapies in CCA.

Role of Cancer Stem Cells in Cholangiocarcinoma and Therapeutic Implications

Cholangiocarcinoma (CCA) is the second most common type of liver cancer, and is highly aggressive with very poor prognosis. CCA is classified into intrahepatic cholangiocarcinoma (iCCA) and extra-hepatic cholangiocarcinoma (eCCA), which is further stratified into perihilar (pCCA) and distal (dCCA). Cancer stem cells (CSCs) are a subpopulation of cancer cells capable of tumor initiation and malignant growth, and are also responsible for chemoresistance. Thus, CSCs play an important role in CCA carcinogenesis. Surface markers such as CD133, CD24, CD44, EpCAM, Sox2, CD49f, and CD117 are important for identifying and isolating CCA CSCs. CSCs are present in the tumor microenvironment (TME), termed ‘CSC niche’, where cellular components and soluble factors interact to promote tumor initiation. Epithelial-to-mesenchymal transition (EMT) is another important mechanism underlying carcinogenesis, involved in the invasiveness, metastasis and chemoresistance of cancer. It has been demonstrated that EMT plays a critical role in generating CSCs. Therapies targeting the surface markers and signaling pathways of CCA CSCs, proteins involved in TME, and immune checkpoint proteins are currently under investigation. Therefore, this review focuses on recent studies on the roles of CSCs in CCA; the possible therapeutic strategies targeting CSCs of CCA are also discussed.

Transforming Growth Factor-Beta (TGFβ) Signaling Pathway in Cholangiocarcinoma

Cholangiocarcinoma is a deadly cancer worldwide, associated with a poor prognosis and limited therapeutic options. Although cholangiocarcinoma accounts for less than 15% of liver primary cancer, its silent nature restricts early diagnosis and prevents efficient treatment. Therefore, it is of clinical relevance to better understand the molecular basis of cholangiocarcinoma, including the signaling pathways that contribute to tumor onset and progression. In this review, we discuss the genetic, molecular, and environmental factors that promote cholangiocarcinoma, emphasizing the role of the transforming growth factor β (TGFβ) signaling pathway in the progression of this cancer. We provide an overview of the physiological functions of TGFβ signaling in preserving liver homeostasis and describe how advanced cholangiocarcinoma benefits from the tumor-promoting effects of TGFβ. Moreover, we report the importance of noncoding RNAs as effector molecules downstream of TGFβ during cholangiocarcinoma progression, and conclude by highlighting the need for identifying novel and clinically relevant biomarkers for a better management of patients with cholangiocarcinoma.

ARID1A knockdown triggers epithelial-mesenchymal transition and carcinogenesis features of renal cells: role in renal cell carcinoma

Down-regulation/mutation of AT-rich interactive domain 1A (ARID1A), a novel tumor suppressor gene, has been reported in various cancers. Nevertheless, its role in renal cell carcinoma (RCC) remained unclear and underinvestigated. We thus evaluated carcinogenesis effects of ARID1A knockdown in nonmalignant Madin-Darby canine kidney (MDCK) renal cells using small interfering RNA (siRNA) against ARID1A (siARID1A). The siARID1A-transfected cells had decreased cell death, increased cell proliferation, and cell cycle shift (from G₀/G₁ to G₂/M) compared with those transfected with controlled siRNA (siControl). Additionally, the siARID1A-transfected cells exhibited epithelial-mesenchymal transition (EMT) shown by greater spindle index, increased mesenchymal markers (fibronectin/vimentin), and decreased epithelial markers (E-cadherin/zonula occludens-1). Moreover, the siARID1A-transfected cells had increases in migratory activity, nuclear size, self-aggregated multicellular spheroid size, invasion capability, chemoresistance (to docetaxel), Snail family transcriptional repressor 1 expression, and TGF-β1 secretion. All of these siARID1A-knockdown effects on the carcinogenic features were reproducible in malignant RCC (786-O) cells, which exhibited a higher degree of carcinogenic phenotypes compared with the nonmalignant MDCK cells. Finally, immunohistochemistry showed obvious decrease in ARID1A protein expression in human RCC tissues (n = 23) compared with adjacent normal renal tissues (n = 23). These data indicate that ARID1A down-regulation triggers EMT and carcinogenesis features of renal cells in vitro, and its role in RCC could be proven in human tissues.-Somsuan, K., Peerapen, P., Boonmark, W., Plumworasawat, S., Samol, R., Sakulsak, N., Thongboonkerd, V. ARID1A knockdown triggers epithelial-mesenchymal transition and carcinogenesis features of renal cells: role in renal cell carcinoma.

CXCL12 expression in intrahepatic cholangiocarcinoma is associated with metastasis and poor prognosis

Intrahepatic cholangiocarcinoma is a rare malignant biliary neoplasm that causes a poor prognosis even after curative hepatectomy. Liver metastasis is the major recurrence pattern of intrahepatic cholangiocarcinoma; therefore, the prevention of liver metastasis is a desirable objective. The aim of this study is to identify gene(s) related to liver metastasis of intrahepatic cholangiocarcinoma and to examine the inhibitory effects on metastasis of intrahepatic cholangiocarcinoma by controlling such gene(s). We collected 3 pairs of intrahepatic cholangiocarcinoma frozen samples, and 36 pairs (primary and metastatic lesions) of intrahepatic cholangiocarcinoma formalin-fixed paraffin-embedded samples, from patients who underwent surgical resection at hospitals related to the Kyushu Study Group of Liver Surgery between 2002 and 2016. We carried out cDNA microarray analyses and immunohistochemistry to identify candidate genes, and evaluated one of them as a therapeutic target using human cholangiocarcinoma cell lines. We identified 4 genes related to liver metastasis using cDNA microarray, and found that CXCL12 was the only gene whose expression was significantly higher in liver metastasis than in primary intrahepatic cholangiocarcinoma by immunohistochemistry (P = .003). In prognosis, patients in the high CXCL12 group showed a significantly poor prognosis in disease-free (P < .0001) and overall survival (P = .0004). By knockdown of CXCL12, we could significantly suppress the invasive and migratory capabilities of 2 human cholangiocarcinoma cell lines. Therefore, CXCL12 might be associated with metastasis and poor prognosis in intrahepatic cholangiocarcinoma.

TGF-β signaling promotes tube-structure-forming growth in pancreatic duct adenocarcinoma

Tube-forming growth is an essential histological feature of pancreatic duct adenocarcinoma (PDAC) and of the pancreatic duct epithelium; nevertheless, the nature of the signals that start to form the tubular structures remains unknown. Here, we showed the clonal growth of PDAC cell lines in a three-dimensional (3D) culture experiment that modeled the clonal growth of PDAC. At the beginning of this study, we isolated the sphere- and tube-forming clones from established mouse pancreatic cancer cell lines via limiting dilution culture using collagen gel. Compared with cells in spherical structures, the cells in the formed tubes exhibited a lower CK19 expression in 3D culture and in the tumor that grew in the abdominal cavity of nude mice. Conversely, the expression of the transforming growth factor β (TGF-β)-signaling target mRNAs was higher in the formed tube vs the spherical structures, suggesting that TGF-β signaling is more active in the tube-forming process than the sphere-forming process. Treatment of sphere-forming clones with TGF-β1 induced tube-forming growth, upregulated the TGF-β-signaling target mRNAs, and yielded electron microscopic findings of a fading epithelial phenotype. In contrast, the elimination of TGF-β-signaling activation by treatment with inhibitors diminished the tube-forming growth and suppressed the expression of the TGF-β-signaling target mRNAs. Moreover, upregulation of the Fn1, Mmp2, and Snai1 mRNAs, which are hallmarks of tube-forming growth in PDAC, was demonstrated in a mouse model of carcinogenesis showing rapid progression because of the aggressive invasion of tube-forming cancer. Our study suggests that the tube-forming growth of PDAC relies on the activation of TGF-β signaling and highlights the importance of the formation of tube structures.

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.

Stochastic phenotype switching leads to intratumor heterogeneity in human liver cancer

Intratumor heterogeneity is increasingly recognized as a major factor impacting diagnosis and personalized treatment of cancer. We characterized stochastic phenotype switching as a mechanism contributing to intratumor heterogeneity and malignant potential of liver cancer. Clonal analysis of primary tumor cell cultures of a human sarcomatoid cholangiocarcinoma identified different types of self-propagating subclones characterized by stable (keratin-7-positive or keratin-7-negative) phenotypes and an unstable phenotype consisting of mixtures of keratin-7-positive and keratin-7-negative cells, which lack stem cell features but may reversibly switch their phenotypes. Transcriptome sequencing and immunohistochemical studies with the markers Zeb1 and CD146/MCAM demonstrated that switching between phenotypes is linked to changes in gene expression related but not identical to epithelial-mesenchymal transition. Stochastic phenotype switching occurred during mitosis and did not correlate with changes in DNA methylation. Xenotransplantation assays with different cellular subclones demonstrated increased tumorigenicity of cells showing phenotype switching, resulting in tumors morphologically resembling the invasive component of primary tumor and metastasis.

CONCLUSION

Our data demonstrate that stochastic phenotype switching contributes to intratumor heterogeneity and that cells with a switching phenotype have increased malignant potential. (Hepatology 2017).

Activation of Vimentin Is Critical to Promote a Metastatic Potential of Cholangiocarcinoma Cells

Cholangiocarcinoma (CCA) is a highly metastatic tumor, and the majority of patients with CCA have a short survival time because there are no available effective treatments. Hence, a better understanding regarding CCA metastasis may provide an opportunity to improve the strategies for treatment. A comparison study between the highly metastatic cells and their parental cells is an approach to uncover the molecular mechanisms underlying the metastatic process. In the present study, a lung metastatic CCA cell line, KKU-214L5, was established by the in vivo selection of the tail vein-injected mouse model. KKU-214L5 cells possessed mesenchymal spindle-like morphology with higher migration and invasion abilities in vitro than the parental cells (KKU-214). KKU-214L5 also exhibited extremely aggressive lung colonization in the tail vein-injected metastatic model. Epithelial-mesenchymal transition (EMT) was clearly observed in KKU-214L5 cells. Significant downregulation of epithelial markers (ZO-1 and claudin-1), with unique upregulation of E-cadherin and mesenchymal markers (vimentin, β-catenin, and slug), was observed in KKU-214L5. Increasing MMP-2 and MMP-9 activities and CD147 expression reflected the high invasion activity in KKU-214L5 cells. Suppression of vimentin using siRNA significantly decreased the migration and invasion capabilities of KKU-214L5 to almost the basal levels of the parental cells without any change on the expression levels of other EMT markers and the activities of MMPs. These results suggest that vimentin activation is essential to potentiate the metastatic characters of CCA cells, and suppression of vimentin expression could be a potential strategy to improve the treatment of CCA, a highly metastatic cancer.

LTBP2 promotes the migration and invasion of gastric cancer cells and predicts poor outcome of patients with gastric cancer

Latent transforming growth factor-β-binding protein (LTBP)2 is a member of the fibrillin/LTBP superfamily of extracellular matrix proteins, and has been demonstrated to exhibit tumor-promoting and tumor-suppressive functions in different types of cancer. However, the function of LTBP2 in gastric cancer (GC) remains unknown. The aim of the present study was to investigate the expression and molecular function of LTBP2 in GC, and to evaluate its prognostic value for patients with GC. The results revealed that the expression of LTBP2 was upregulated in GC tissues and cell lines. Increased LTBP2 expression was associated with poor overall survival in patients with early-stage [tumor-node-metastasis (TNM) I/II] and late-stage (TNM III/IV) GC. Furthermore, silencing of LTBP2 effectively suppressed the proliferation, migration, invasion and epithelial-mesenchymal transition in GC cells. These results suggested that LTBP2 may be considered as a potential therapeutic target and a promising prognostic biomarker for human GC.

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.

CD133 expression in cancer cells predicts poor prognosis of non-mucin producing intrahepatic cholangiocarcinoma

BACKGROUND

CD133 is a marker of stem cells as well cancer stem cells. This study investigated the association between CD133 expression in cancer cells and the clinical outcome of non-mucin producing intrahepatic cholangiocarcinoma (ICC).

METHODS

Fifty-seven non-mucin producing ICC patients were enrolled in this study. Immunohistochemistry (IHC) and immunofluorescence staining for CD133 as well as other cancer-associated proteins, including cytokeratin 19, TGF-β1, p-Smad2 and epithelial-mesenchymal transition (EMT) markers S100A4, E-Cadherin and Vimentin were analyzed.

RESULTS

IHC staining showed that tumor cells in 52.6% of patients expressed CD133. The CD133+ patients had significantly higher metastasis rate than those without CD133+ tumor cells (36.7% vs. 10.1%, p = 0.03). The CD133+ patients had shorter overall and disease-free survival time as compared to the CD133- patients. Furthermore, 90.9% of CD133+ patients developed cancer recurrence, as compared to 64.3% of CD133- patients (p = 0.02). As compared to CD133- patients, tumor cells in CD133+ patients demonstrated high levels of TGF-β/p-Smad2 as well as EMT-like alteration, characterized by loss of E-Cadherin and expression of Vimentin and S100A4.

CONCLUSIONS

CD133 expression in ICC tumor cells indicates poor prognosis of the disease and might be associated with TGF-β related EMT alterations.

Desmoplastic Tumor Microenvironment and Immunotherapy in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a dismal disease which often is diagnosed at a late stage where the tumor is locally advanced, metastatic, and, as a result, is associated with low resectability. The heterogeneity of this cancer type is a major reason why the majority of patients fail to respond to therapy, and surgery remains their only curative option. Among patients who undergo surgical intervention, such tumors typically recur in 50% of cases within 1year. Thus, CCA is among the most aggressive and chemoresistant malignancies. CCA is characterized by marked tumor reactive stroma, a fibrogenic connective tissue which surrounds and infiltrates the tumor epithelium. This desmoplastic environment presents a clinical challenge, limiting drug delivery and supporting the growth of the tumor mass. In this review we attempt to highlight key pathways involved in cell to cell communication between the tumor epithelium and stroma, the immune components, and opportunities for novel strategies to improve patient outcome.

HK3 overexpression associated with epithelial-mesenchymal transition in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a common cancer worldwide. The main cause of death in CRC includes tumor progression and metastasis. At molecular level, these processes may be triggered by epithelial-mesenchymal transition (EMT) and necessitates specific alterations in cell metabolism. Although several EMT-related metabolic changes have been described in CRC, the mechanism is still poorly understood.

RESULTS

Using CrossHub software, we analyzed RNA-Seq expression profile data of CRC derived from The Cancer Genome Atlas (TCGA) project. Correlation analysis between the change in the expression of genes involved in glycolysis and EMT was performed. We obtained the set of genes with significant correlation coefficients, which included 21 EMT-related genes and a single glycolytic gene, HK3. The mRNA level of these genes was measured in 78 paired colorectal cancer samples by quantitative polymerase chain reaction (qPCR). Upregulation of HK3 and deregulation of 11 genes (COL1A1, TWIST1, NFATC1, GLIPR2, SFPR1, FLNA, GREM1, SFRP2, ZEB2, SPP1, and RARRES1) involved in EMT were found. The results of correlation study showed that the expression of HK3 demonstrated a strong correlation with 7 of the 21 examined genes (ZEB2, GREM1, TGFB3, TGFB1, SNAI2, TWIST1, and COL1A1) in CRC.

CONCLUSIONS

Upregulation of HK3 is associated with EMT in CRC and may be a crucial metabolic adaptation for rapid proliferation, survival, and metastases of CRC cells.

Role of AP-2α and MAPK7 in the regulation of autocrine TGF-β/miR-200b signals to maintain epithelial-mesenchymal transition in cholangiocarcinoma

Background

Cholangiocarcinoma (CCA) is characterized by early lymphatic, metastasis, and low survival rate. Epithelial-mesenchymal transition (EMT) is able to induce tumor metastasis. Although the TGF-β/miR-200 signals promote EMT in various types of cancer, the regulatory mechanism in CCA is still unclear.

Methods

Expression of miR-200b, TGF-β, and EMT markers were measured in tumor samples and cell lines by qRT-PCR and western blot. CCK8 assay was performed to measure the cell viability. Transwell assay was used to evaluate migration and invasion. The target genes of miR-200b and transcription factor of TGF-β were analyzed using dual-luciferase reporter system.

Results

We have demonstrated that CCA exhibited remarkable EMT phenotype and miR-200b was reduced in CCA patients (n = 20) and negatively correlated to TGF-β. Moreover, two CCA cells, HCCC, and RBE, with epithelial appearances treated with TGF-β, showed fibroblastic-like cell morphology with downregulated miR-200b expression. Forced expression of miR-200b abrogated TGF-β-induced EMT initiation, with decreased cell proliferation, migration, and invasion in vitro. Also, TFAP2A (encode AP-2α) and MAPK7 were found to be targeted by miR-200b to downregulate EMT and AP-2α inhibited miR-200b by directly promoting transcription of TGFB1. Overexpression of MAPK7 significantly reversed miR-200b-induced inhibition of EMT, migration, and proliferation by increasing the expression of TGF-β, cyclin D1, and Cdk2. Further, the administration of miR-200b induced a remarkably tumor regression in vivo and reduced the effect of TGF-β-related EMT in AP-2α and MAPK7-dependent manner.

Conclusions

Our study highlights that miR-200b-based gene therapy is effective in the treatment of CCA.

Blocking ERK1/2 signaling impairs TGF-β1 tumor promoting function but enhances its tumor suppressing role in intrahepatic cholangiocarcinoma cells

Background

Transforming growth factor-β (TGF-β) plays a paradoxical role in cancer: it suppresses proliferation at early stages but promotes metastasis at late stages. This cytokine is upregulated in cholangiocarcinoma and is implicated in cholangiocarcinoma invasion and metastasis. Here we investigated the roles of non-Smad pathway (ERK1/2) and Smad in TGF-β tumor promoting and suppressing activities in intrahepatic cholangiocarcinoma (ICC) cells.

Methods

TGF-β1 effects on proliferation, invasion and migration of ICC cells, KKU-M213 and/or HuCCA-1, were investigated using MTT, colony formation, in vitro Transwell and wound healing assays. Levels of mRNAs and proteins/phospho-proteins were measured by quantitative (q)RT-PCR and Western blotting respectively. E-cadherin localization was examined by immunofluorescence and secreted MMP-9 activity was assayed by gelatin zymography. The role of ERK1/2 signaling was evaluated by treating cells with TGF-β1 in combination with MEK1/2 inhibitor U0126, and that of Smad2/3 and Slug using siSmad2/3- and siSlug-transfected cells.

Results

h-TGF-β1 enhanced KKU-M213 cell invasion and migration and induced epithelial-mesenchymal transition as shown by an increase in vimentin, Slug and secreted MMP-9 levels and by a change in E-cadherin localization from membrane to cytosol, while retaining the cytokine’s ability to attenuate cell proliferation. h-TGF-β1 stimulated Smad2/3 and ERK1/2 phosphorylation, and the MEK1/2 inhibitor U0126 attenuated TGF-β1-induced KKU-M213 cell invasion and MMP-9 production but moderately enhanced the cytokine growth inhibitory activity. The latter effect was more noticeable in HuCCA-1 cells, which resisted TGF-β-anti-proliferative activity. Smad2/3 knock-down suppressed TGF-β1 ability to induce ERK1/2 phosphorylation, Slug expression and cell invasion, whereas Slug knock-down suppressed cell invasion and vimentin expression but marginally affected ERK1/2 activation and MMP-9 secretion. These results indicate that TGF-β1 activated ERK1/2 through Smad2/3 but not Slug pathway, and that ERK1/2 enhanced TGF-β1 tumor promoting but repressed its tumor suppressing functions.

Conclusions

Inhibiting ERK1/2 activation attenuates TGF-β1 tumor promoting effect (invasion) but retains its tumor suppressing role, thereby highlighting the importance of ERK1/2 in resolving the TGF-β paradox switch.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-017-0454-2) contains supplementary material, which is available to authorized users.

TGF-β signaling is an effective target to impair survival and induce apoptosis of human cholangiocarcinoma cells: A study on human primary cell cultures

Cholangiocarcinoma (CCA) and its subtypes (mucin- and mixed-CCA) arise from the neoplastic transformation of cholangiocytes, the epithelial cells lining the biliary tree. CCA has a high mortality rate owing to its aggressiveness, late diagnosis and high resistance to radiotherapy and chemotherapeutics. We have demonstrated that CCA is enriched for cancer stem cells which express epithelial to mesenchymal transition (EMT) traits, with these features being associated with aggressiveness and drug resistance. TGF-β signaling is upregulated in CCA and involved in EMT. We have recently established primary cell cultures from human mucin- and mixed-intrahepatic CCA. In human CCA primary cultures with different levels of EMT trait expression, we evaluated the anticancer effects of: (i) CX-4945, a casein kinase-2 (CK2) inhibitor that blocks TGF-β1-induced EMT; and (ii) LY2157299, a TGF-β receptor I kinase inhibitor. We tested primary cell lines expressing EMT trait markers (vimentin, N-cadherin and nuclear catenin) but negative for epithelial markers, and cell lines expressing epithelial markers (CK19-positive) in association with EMT traits. Cell viability was evaluated by MTS assays, apoptosis by Annexin V FITC and cell migration by wound-healing assay. Results: at a dose of 10 μM, CX4945 significantly decreased cell viability of primary human cell cultures from both mucin and mixed CCA, whereas in CK19-positive cell cultures, the effect of CX4945 on cell viability required higher concentrations (>30μM). At the same concentrations, CX4945 also induced apoptosis (3- fold increase vs controls) which correlated with the expression level of CK2 in the different CCA cell lines (mucin- and mixed-CCA). Indeed, no apoptotic effects were observed in CK19-positive cells expressing lower CK2 levels. The effects of CX4945 on viability and apoptosis were associated with an increased number of γ-H2ax (biomarker for DNA double-strand breaks) foci, suggesting the active role of CK2 as a repair mechanism in CCAs. LY2157299 failed to influence cell proliferation or apoptosis but significantly inhibited cell migration. At a 50 μM concentration, in fact, LY2157299 significantly impaired (at 24, 48 and 120 hrs) the wound-healing of primary cell cultures from both mucin-and mixed-CCA. In conclusion, we demonstrated that CX4945 and LY2157299 exert relevant but distinct anticancer effects against human CCA cells, with CX4945 acting on cell viability and apoptosis, and LY2157299 impairing cell migration. These results suggest that targeting the TGF-β signaling with a combination of CX-4945 and LY2157299 could have potential benefits in the treatment of human CCA.

Salinomycin enhances doxorubicin sensitivity through reversing the epithelial-mesenchymal transition of cholangiocarcinoma cells by regulating ARK5

Chemotherapy response rates in patients with cholangiocarcinoma remain low, primarily due to the development of drug resistance. Epithelial-mesenchymal transition (EMT) of cancer cells is widely accepted to be important for metastasis and progression, but it has also been linked to the development of chemoresistance. Salinomycin (an antibiotic) has shown some potential as a chemotherapeutic agent as it selectively kills cancer stem cells, and has been hypothesized to block the EMT process. In this study, we investigated whether salinomycin could reverse the chemoresistance of cholangiocarcinoma cells to the chemotherapy drug doxorubicin. We found that combined salinomycin with doxorubicin treatment resulted in a significant decrease in cell viability compared with doxorubicin or salinomycin treatment alone in two cholangiocarcinoma cell lines (RBE and Huh-28). The dosages of both drugs that were required to produce a cytotoxic effect decreased, indicating that these two drugs have a synergistic effect. In terms of mechanism, salinomycin reversed doxorubicin-induced EMT of cholangiocarcinoma cells, as shown morphologically and through the detection of EMT markers. Moreover, we showed that salinomycin treatment downregulated the AMP-activated protein kinase family member 5 (ARK5) expression, which regulates the EMT process of cholangiocarcinoma. Our results indicated that salinomycin reversed the EMT process in cholangiocarcinoma cells by inhibiting ARK5 expression and enhanced the chemosensitivity of cholangiocarcinoma cells to doxorubicin. Therefore, a combined treatment of salinomycin with doxorubicin could be used to enhance doxorubicin sensitivity in patients with cholangiocarcinoma.

Intrahepatic cholangiocarcinoma: Molecular markers for diagnosis and prognosis

Intrahepatic cholangiocarcinoma (iCCA) is the second most common primary liver tumor with increasing incidence worldwide. The outcome of patients with iCCA is dismal owing to tumor's aggressiveness, late diagnosis and lack of effective treatment options. Detection of the tumor at early stages may make surgical resection, as only potential curative treatment, more feasible. Unfortunately, despite recent developments in imaging modalities and laboratory tests, the diagnosis of iCCA remains challenging and patients often present in advanced stages when surgery cannot be offered. Moreover, accurate assessment of disease burden is critical to optimize management strategy, including the use of adjuvant therapies and clinical trials. Identifying iCCA specific diagnostic and prognostic biomarkers has been a focus of interest among many investigators with a progressive increase in data on iCCA related to advances in "omics" technologies. We herein summarize iCCA biomarkers and define the molecular mechanisms underlying iCCA carcinogenesis, as well as highlight potential diagnostic and prognostic application of molecular biomarkers.

Inhibition of the apelin/apelin receptor axis decreases cholangiocarcinoma growth

PURPOSE

Cholangiocarcinoma (CCA) is a malignancy of the biliary epithelium that is associated with low five-year survival. The apelin receptor (APLNR), which is activated by the apelin peptide, has not been studied in CCA. The purpose of this study is to determine if inhibition of the apelin/APLNR axis can inhibit CCA growth.

METHODS

Immunohistochemistry, rtPCR, immunofluorescence, flow cytometry, and ELISA was used to measure APLNR expression in human CCA cells and tissues. Mz-ChA-1 cells were treated with increasing concentrations of apelin and ML221, an APLNR antagonist. Expression of proliferative and angiogenic genes were measured via rtPCR. In vivo, Mz-ChA-1 cells were injected into the flanks of nu/nu mice, which were treated with ML221 (150 μg/kg) via tail vein injection.

RESULTS

Expression of the apelin/APLNR axis was increased in CCA. In vitro, CCA proliferation and angiogenesis was inhibited by ML221 treatment. ML221 treatment significantly decreased tumor growth in nu/nu mice.

CONCLUSION

The apelin/APLNR axis regulates CCA proliferation and angiogenesis. Inhibition of the apelin/APLNR axis decreases tumor growth in our xenograft model. Targeting APLNR signaling has the potential to serve as a novel, tumor directed therapy for CCA.

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.

TGF-β Signaling in Gastrointestinal Cancers: Progress in Basic and Clinical Research

Transforming growth factor (TGF)-β superfamily proteins have many important biological functions, including regulation of tissue differentiation, cell proliferation, and migration in both normal and cancer cells. Many studies have reported that TGF-β signaling is associated with disease progression and therapeutic resistance in several cancers. Similarly, TGF-β-induced protein (TGFBI)—a downstream component of the TGF-β signaling pathway—has been shown to promote and/or inhibit cancer. Here, we review the state of basic and clinical research on the roles of TGF-β and TGFBI in gastrointestinal cancers.

An S100P-positive biliary epithelial field is a preinvasive intraepithelial neoplasm in nodular-sclerosing cholangiocarcinoma

Nodular-sclerosing cholangiocarcinoma (NS-CCA) is a common CCA of the intrahepatic large, perihilar, and distal bile ducts. Intraepithelial biliary neoplasms, such as the mucosal extension of carcinoma and preinvasive neoplastic lesions (ie, biliary intraepithelial neoplasia) reportedly occur in the bile ducts around CCA. In the present study, we collectively refer to these intraepithelial lesions as "intraepithelial neoplasms of the bile duct (IENBs)". We examined the IENBs in 57 surgically resected cases of NS-CCA. S100P immunostaining was used to help detect IENBs. The IENBs formed field(s) of continuous neoplastic biliary epithelial cells and showed a flat, micropapillary, or papillotubular configuration. IENBs could be classified into 3 categories based on their atypia: group A (neoplastic but not enough for malignancy), B (neoplastic and sufficiently well differentiated for high-grade dysplasia), and C (overtly malignant and variably differentiated). IENB was found in 31 of 57 cases, with group C the most common (26 cases) followed by group B (22 cases) and group A (16 cases). The expression of cancer-related molecules and MIB-1 index of groups A and B differed from those of invasive CCA, whereas these features of group C were relatively similar to those of invasive CCA. In conclusion, IENB was not infrequently found in NS-CCA and could be classified into 3 grades. Preinvasive lesions (biliary intraepithelial neoplasias) are likely to be found in groups A and B, whereas cancerization would be included in group C. The classification of IENB may be useful for future studies of the preinvasive intraepithelial neoplastic lesions of NS-CCAs.

A supercritical-CO2 extract of Ganoderma lucidum spores inhibits cholangiocarcinoma cell migration by reversing the epithelial-mesenchymal transition

BACKGROUND

Ganoderma lucidum (G. lucidum) is an oriental medical mushroom that has been widely used in Asian countries for centuries to prevent and treat different diseases, including cancer.

HYPOTHESIS/PURPOSE

The objective of this study was to investigate the effect of A supercritical-CO2 extract of G. lucidum spores on the transforming growth factor beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) of cholangiocarcinoma cells.

STUDY DESIGN

This was an in vitro study with human cholangiocarcinoma TFK-1 cells treated with varying concentrations of G. lucidum.

METHODS

A supercritical-CO2 extract of G. lucidum spores (GLE) was obtained from completely sporoderm-broken germinating G. lucidum spores by supercritical fluid carbon dioxide (SCF-CO2) extraction. GLE pre-incubated with human cholangiocarcinoma TFK-1 cells prior to TGF-β1 treatment (2ng/ml) for 48h. Changes in EMT markers were analyzed by western blotting and immunofluorescence. The formation of F-actin stress fibers was assessed via immunostaining with phalloidin and examined using confocal microscopy. Additionally, the effect of the GLE on TGF-β1-induced migration was investigated by a Boyden chamber assay.

RESULTS

TGF-β1-induced reduction in E-cadherin expression was associated with a loss of epithelial morphology and cell-cell contact. Concomitant increases in N-cadherin and Fibronectin were evident in predominantly elongated fibroblast-like cells. The GLE suppressed the TGF-β1-induced morphological changes and the changes in cadherin expression, and also inhibited the formation of F-actin stress fibers, which are a hallmark of EMT. The GLE also inhibited TGF-β1-induced migration of TFK-1 cells.

CONCLUSION

Our findings provide new evidence that GLE suppress cholangiocarcinoma migration in vitro through inhibition of TGF-β1-induced EMT. The GLE may be clinically applied in the prevention and/or treatment of cancer metastasis.

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.

Radiation-induced expression of HOTAIR, Snail and E-cadherin in esophageal squamous cell carcinoma cells

AIM: To investigate the effect of X-ray radiation on the expression of HOTAIR and epithelial-mesenchymal transition (EMT) related factors in esophageal squamous cell carcinoma (ESCC).

METHODS: Eca109 cells were irradiated with 0, 2, 4, 6, or 8 Gy of X-rays. After 0, 2, 4, 8, 16, or 24 h of radiation, the expression of HOTAIR, Snail and E-cadherin was detected by qRT-PCR and Western blot.

RESULTS: In Eca109 cells irradiated for 24 h, X-ray dose-dependently increased HOTAIR and Snail expression levels but decreased E-cadherin mRNA and protein expression. The mRNA expression levels of HOTAIR and Snail in the 6 Gy and 8 Gy groups were significantly higher than those in the 0 Gy group. Of note, Snail protein level dramatically increased in the 4 Gy group. The expression of E-cadherin mRNA and protein was statistically lower in the 6 Gy and 8 Gy groups compared with the 0 Gy group (P < 0.01). In Eca109 cells irradiated with 8 Gy X-ray, X-ray time-dependently increased the expression of HOTAIR and Snail but decreased E-cadherin mRNA and protein expression. HOTAIR and Snail mRNA and protein expression was significantly higher in the 8 and 16 h groups than in the 0 h group, while the expression of E-cadherin mRNA and protein was gradually decreased in the 8 h group compared with the 0 h group.

CONCLUSION: X-ray induces abnormal expression of HOTAIR, Snail and E-cadherin time- and dose-dependently, which may result in the occurrence of cellular radioresistance.

Epithelial-to-Mesenchymal Transition and Cancer Invasiveness: What Can We Learn from Cholangiocarcinoma?

In addition to its well-established role in embryo development, epithelial-to-mesenchymal transition (EMT) has been proposed as a general mechanism favoring tumor metastatization in several epithelial malignancies. Herein, we review the topic of EMT in cholangiocarcinoma (CCA), a primary liver cancer arising from the epithelial cells lining the bile ducts (cholangiocytes) and characterized by an abundant stromal reaction. CCA carries a dismal prognosis, owing to a pronounced invasiveness and scarce therapeutic opportunities. In CCA, several reports indicate that cancer cells acquire a number of EMT biomarkers and functions. These phenotypic changes are likely induced by both autocrine and paracrine signals released in the tumor microenvironment (cytokines, growth factors, morphogens) and intracellular stimuli (microRNAs, oncogenes, tumor suppressor genes) variably associated with specific disease mechanisms, including chronic inflammation and hypoxia. Nevertheless, evidence supporting a complete EMT of neoplastic cholangiocytes into stromal cells is lacking, and the gain of EMT-like changes by CCA cells rather reflects a shift towards an enhanced pro-invasive phenotype, likely induced by the tumor stroma. This concept may help to identify new biomarkers of early metastatic behavior along with potential therapeutic targets.

TGF-β1 Reduces miR-29a Expression to Promote Tumorigenicity and Metastasis of Cholangiocarcinoma by Targeting HDAC4

Transforming growth factor β1 (TGF-β1) and miRNAs play important roles in cholangiocarcinoma progression. In this study, miR-29a level was found significantly decreased in both cholangiocarcinoma tissues and tumor cell lines. TGF-β1 reduced miR-29a expression in tumor cell lines. Furthermore, anti-miR-29a reduced the proliferation and metastasis capacity of cholangiocarcinoma cell lines in vitro, overexpression of miR-29a counteracted TGF-β1-mediated cell growth and metastasis. Subsequent investigation identified HDAC4 is a direct target of miR-29a. In addition, restoration of HDAC4 attenuated miR-29a-mediated inhibition of cell proliferation and metastasis. Conclusions: TGF-β1/miR-29a/HDAC4 pathway contributes to the pathogenesis of cholangiocarcinoma and our data provide new therapeutic targets for cholangiocarcinoma.

Tumor Microenvironment Versus Cancer Stem Cells in Cholangiocarcinoma: Synergistic Effects?

Cholangiocarcinoma (CCAs) may be defined as tumors that derived from the biliary tree with the differentiation in the biliary epithelial cells. This tumor is malignant, extremely aggressive with a poor prognosis. It can be treated surgically and its pathogenesis is poorly understood. The tumor microenvironment (TME) is a very important factor in the regulation of tumor angiogenesis, invasion, and metastasis. Besides cancer stem cells (CSCs) can modulate tumor growth, stroma formation, and migratory capability. The initial stage of tumorigenesis is characterized by genetic mutations and epigenetic alterations due to intrinsic factors which lead to the generation of oncogenes thus inducing tumorigenesis. CSCs may result from precancerous stem cells, cell de-differentiation, normal stem cells, or an epithelial-mesenchymal transition (EMT). CSCs have been found in the cancer niche, and EMT may occur early within the tumor microenvironment. Previous studies have demonstrated evidence of cholangiocarcinoma stem cells (CD133, CD24, EpCAM, CD44, and others) and the presence of these markers has been associated with malignant potential. The interaction between TME and cholangiocarcinoma stem cells via signaling mediators may create an environment that accommodates tumor growth, yielding resistance to cytotoxic insults (chemotherarapeutic). While progress has been made in the understanding of the mechanisms, the interactions in the tumorigenic process still remain a major challenge. Our review, addresses recent concepts of TME-CSCs interaction and will emphasize the importance of early detection with the use of novel diagnostic mechanisms such as CCA-CSC biomarkers and the importance of tumor stroma to define new treatments. J. Cell. Physiol. 231: 768-776, 2016. © 2015 Wiley Periodicals, Inc.

Human antigen R mediated post-transcriptional regulation of epithelial-mesenchymal transition related genes in diabetic nephropathy

BACKGROUND

Human antigen R (HuR) is a ubiquitously expressed RNA-binding protein that modulates gene expression at the post-transcriptional level. While cytoplasmic HuR expression was identified as a marker in epithelial-mesenchymal transition (EMT) process of several types of cancer, its role in diabetic nephropathy (DN) remains unclear.

METHODS

Renal biopsies from Type 2 diabetic patients and STZ-induced DN rats were stained for HuR and EMT markers. Redistribution of HuR was detected by immunostaining and western blot in high glucose stimulated cells. RNAi was used to supress HuR expression. The binding affinity for EMT-related genes was evaluated by immunoprecipitation.

RESULTS

Cytoplasmic HuR expression was elevated in human and rat DN specimens along with EMT changes compared to normal controls. HuR shuttling between nucleus and cytoplasm facilitated epithelial to mesenchymal transition in renal epithelial cells. The suppression of HuR partially inhibited EMT of high glucose stimulated HK-2 cells. Furthermore, HuR bound to 3'-UTRs of critical cytokines or transcription factors mRNA involved in EMT process.

CONCLUSION

Acquired phenotypic traits of EMT were partially through the enhanced HuR-binding proteins and its post-transcriptional regulation role in DN.

Molecular mechanism of local drug delivery with Paclitaxel-eluting membranes in biliary and pancreatic cancer: new application for an old drug

Implantation of self-expanding metal stents (SEMS) is palliation for patients suffering from inoperable malignant obstructions associated with biliary and pancreatic cancers. Chemotherapeutic agent-eluting stents have been developed because SEMS are susceptible to occlusion by tumor in-growth. We reported recently that paclitaxel-eluting SEMS provide enhanced local drug delivery in an animal model. However, little is known about the molecular mechanisms by which paclitaxel-eluting stents attenuate tumor growth. We investigated the signal transduction pathways underlying the antiproliferative effects of a paclitaxel-eluting membrane (PEM) implanted in pancreatic/cholangiocarcinoma tumor bearing nude mice. Molecular and cellular alterations were analyzed in the PEM-implanted pancreatic/cholangiocarcinoma xenograft tumors by Western blot, immunoprecipitation, and immunofluorescence. The quantities of paclitaxel released into the tumor and plasma were determined by liquid chromatography-tandem mass spectroscopy. Paclitaxel from the PEM and its diffusion into the tumor inhibited angiogenesis, which involved suppression of mammalian target of rapamycin (mTOR) through regulation of hypoxia inducible factor (HIF-1) and increased apoptosis. Moreover, implantation of the PEM inhibited tumor-stromal interaction-related expression of proteins such as CD44, SPARC, matrix metalloproteinase-2, and vimentin. Local delivery of paclitaxel from a PEM inhibited growth of pancreatic/cholangiocarcinoma tumors in nude mice by suppressing angiogenesis via the mTOR and inducing apoptosis signal pathway.

Impact of microenvironment and stem-like plasticity in cholangiocarcinoma: molecular networks and biological concepts

Clinical complexity, anatomic diversity and molecular heterogeneity of cholangiocarcinoma (CCA) represent a major challenge in the assessment of effective targeted therapies. Molecular and cellular mechanisms underlying the diversity of CCA growth patterns remain a key issue of clinical concern. Crucial questions comprise the nature of the CCA-origin, the initial target for cellular transformation as well as the relationship with the cancer stem cells (CSC) concept. Additionally, since CCA often develops in the context of an inflammatory milieu (cirrhosis and cholangitis), the stromal compartment or tumour microenvironment (TME) likely promotes initiation and progression of this malignancy, contributing to its heterogeneity. This review will emphasize the dynamic interplay between stem-like intrinsic and TME-extrinsic pathways, which may represent novel options for multi-targeted therapies in CCA.