Quantitative changes in tumor-associated M2 macrophages characterize cholangiocarcinoma and their association with metastasis

The role of extracellular vesicles in cholangiocarcinoma tumor microenvironment

Cholangiocarcinoma (CCA) is a highly aggressive malignant tumor that originates from the biliary system. With restricted treatment options at hand, the challenging aspect of early CCA diagnosis leads to a bleak prognosis. Besides the intrinsic characteristics of tumor cells, the generation and progression of CCA are profoundly influenced by the tumor microenvironment, which engages in intricate interactions with cholangiocarcinoma cells. Of notable significance is the role of extracellular vesicles as key carriers in enabling communication between cancer cells and the tumor microenvironment. This review aims to provide a comprehensive overview of current research examining the interplay between extracellular vesicles and the tumor microenvironment in the context of CCA. Specifically, we will emphasize the significant contributions of extracellular vesicles in molding the CCA microenvironment and explore their potential applications in the diagnosis, prognosis assessment, and therapeutic strategies for this aggressive malignancy.

Intrahepatic Cholangiocarcinoma and Hepatocellular Carcinoma: Real-life Data on Liver Disease, Treatment and Prognosis

Background and Aims

Hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA) have common features and differences. This real-life study investigated their characteristics, treatment modalities, and prognoses.

Methods

This retrospective comparative study was performed in 1,075 patients seen at one tertiary center between January 2008 and December 2020. Overall survival (OS) was estimated by the Kaplan-Meier method. Subclassification of iCCAs after histological and radiological review, and molecular profiling was performed.

Results

HCCs patients were more likely to have early-stage disease than iCCA patients. iCCA patients were more likely to be female, especially those patients without cirrhosis (43% vs. 17%). Cirrhosis was prominent among HCC patients (89% vs. 34%), but no difference in underlying liver disease among cirrhotic patients was found. OS of HCC patients was 18.4 (95% CI: 6.4, 48.3) months, that of iCCA patients was 7.0 (95% CI: 3.4, 20.1) months. OS of Barcelona Clinic Liver Cancer C HCC patients was 7.8 (95% CI: 4.3, 14.2) months, that of advanced/metastatic iCCA patients was 8.5 (95% CI: 5.7, 12.3) months. In patients treated with sorafenib, OS was longer in HCC patients who received subsequent tyrosine kinase inhibitor therapies. No significant OS difference was found between iCCA patients with and without cirrhosis or according to histological subtype. A targetable molecular alteration was detected in 50% of the iCCA patients.

Conclusions

In this French series, cirrhosis was common in iCCA, which showed etiological factors comparable to those of HCC, implying a distinct oncogenic pathway. Both entities had a dismal prognosis at advanced stages. However, systemic therapies sequencing in HCC and molecular profiling in iCCA offer new insights.

DLGAP5 promotes gallbladder cancer migration and tumor-associated macrophage M2 polarization by activating cAMP

BACKGROUND

Although disc large associated protein family (DLGAP5) has been reported to be involved in a variety of tumor pathologic processes, its expression and mechanism in gallbladder cancer (GBC) are still uncertain. Macrophages were divided into M1 and M2 macrophages. TAM is more closely defined as M2 polarized macrophages, which plays a key role in cancer progression.

OBJECTIVE

To clarify the role of disc large associated protein family (DLGAP5) in gallbladder cancer (GBC) progression and investigate the mechanism.

METHODS

Differential genes in 10 normal paracancer tissues and 10 GBC tissues in GSE139682 from NCBI-GEO were analyzed by R language. Bioinformation analysis and clinical sample analysis were performed to detect DLGAP5 expression in GBC and its correlation with prognosis. CCK-8, EDU, transwell, wound closure, and Immunoblot were performed to detect its effects on the function of GBC cells. GST-pulldown showed the direct interact between DLGAP5 and cAMP. Macrophage polarization assay was further conducted to detect the effects of DLGAP5 on macrophage M2 polarization. The tumor growth assays were further conducted to confirm its role in mice.

RESULTS

Biological analysis and clinical samples confirmed that DLGAP5 was increased in GBC and strongly related to poor prognosis in patients with GBC. After overexpression of DLGAP5 in GBC cell lines, such as GBC-SD and NOZ cells, cell proliferation and migration were enhanced, and macrophages were polarized to M2. However, after DLGAP5 is knocked down, there is opposite effect. Mechanistically, DLGAP5 promotes the growth and migration of GBC-SD and NOZ cells and the M2 polarization of THP-1-derived macrophages by activating cyclic adenosine monophosphate (cAMP) pathway. In vivo, GBC-SD with DLGAP5 knockdown was subcutaneously injected into nude mice. It was found that after DLGAP5 knockdown, both tumor volume and tumor were reduced, and indicators related to proliferation and M2 polarization decreased.

CONCLUSION

Our study shows that DLGAP5 is significantly elevated in GBC and is strongly related to poor prognosis in patients with GBC. DLGAP5 promotes GBC proliferation, migration, and M2 polarization of macrophages through cAMP pathway, which provides a theoretical basis for the treatment of GBC and may become a promising therapeutic target.

Metabolic-related gene signatures for survival prediction and immune cell subtypes associated with prognosis in intrahepatic cholangiocarcinoma

OBJECTIVES

Our study aimed to reveal the metabolic-related gene signatures for survival prediction and immune cell subtypes associated with IHCC prognosis.

METHODS

Differentially expressed metabolic genes were identified between survival group and dead group which were divided according to survival at discharge. Recursive feature elimination (RFE) and randomForest (RF) algorithms were applied to optimize the combination of feature metabolic genes, which were used to generate SVM classifier. Performance of SVM classifier was evaluated by receiver operating characteristic (ROC) curves. Gene set enrichment analysis (GSEA) was conducted to uncover the activated pathways in high risk group, and differences in immune cell distributions were revealed.

RESULTS

There were 143 differentially expressed metabolic gens. RFE and RF identified 21 overlapping differentially expressed metabolic genes, and the constructed SVM classifier had excellent accuracy in training and validation dataset. RS survival prediction model was consisted of 10 metabolic genes. RS model had reliable predictive capability in the training and validation dataset. GSEA revealed 15 significant KEGG pathways that were relatively activated in the high risk group. High risk group had obviously lower counts of B cell naive and T cell CD4+ memory resting, while higher counts of B cell plasma and macrophage M2.

CONCLUSION

Prognostic prediction model of 10 metabolic genes could accurately predict the prognosis of IHCC patients.

Immune microenvironment of cholangiocarcinoma: Biological concepts and treatment strategies

Cholangiocarcinoma is characterized by a poor prognosis with limited treatment and management options. Chemotherapy using gemcitabine with cisplatin is the only available first-line therapy for patients with advanced cholangiocarcinoma, although it offers only palliation and yields a median survival of < 1 year. Recently there has been a resurgence of immunotherapy studies focusing on the ability of immunotherapy to inhibit cancer growth by impacting the tumor microenvironment. Based on the TOPAZ-1 trial, the US Food and Drug Administration has approved the combination of durvalumab and gemcitabine with cisplatin as the first-line treatment of cholangiocarcinoma. However, immunotherapy, like immune checkpoint blockade, is less effective in cholangiocarcinoma than in other types of cancer. Although several factors such as the exuberant desmoplastic reaction are responsible for cholangiocarcinoma treatment resistance, existing literature on cholangiocarcinoma cites the inflammatory and immunosuppressive environment as the most common factor. However, mechanisms activating the immunosuppressive tumor microenvironment contributing to cholangiocarcinoma drug resistance are complicated. Therefore, gaining insight into the interplay between immune cells and cholangiocarcinoma cells, as well as the natural development and evolution of the immune tumor microenvironment, would provide targets for therapeutic intervention and improve therapeutic efficacy by developing multimodal and multiagent immunotherapeutic approaches of cholangiocarcinoma to overcome the immunosuppressive tumor microenvironment. In this review, we discuss the role of the inflammatory microenvironment-cholangiocarcinoma crosstalk and reinforce the importance of inflammatory cells in the tumor microenvironment, thereby highlighting the explanatory and therapeutic shortcomings of immunotherapy monotherapy and proposing potentially promising combinational immunotherapeutic strategies.

The Hallmarks of Liver Fluke Related Cholangiocarcinoma: Insight into Drug Target Possibility

Cholangiocarcinoma (CCA) is a malignant tumor of the biliary tree that is classified into three groups based on its anatomic location: intrahepatic (iCCA), perihilar (pCCA), and distal (dCCA). Perihilar CCA is the most common type and accounts for 50-60% of CCA cases. It is followed by distal CCA and then intrahepatic CCA that account for 20-30% and 10-20% of cases, respectively. This chapter discusses the hallmarks of liver fluke related CCA and explores insights into drug target possibilities.

Spatiotemporal analysis of tumour-infiltrating immune cells in biliary carcinogenesis

BACKGROUND

Intraductal papillary neoplasms (IPN) and biliary epithelial neoplasia (BilIN) are well-defined precursor lesions of biliary tract carcinoma (BTC). The aim of this study was to provide a comprehensive characterisation of the inflammatory microenvironment in BTC precursor lesions.

METHODS

Immunohistochemistry was employed to assess tumour-infiltrating immune cells in tissue samples from patients, for whom precursor lesions were identified alongside invasive BTC. The spatiotemporal evolution of the immune microenvironment during IPN-associated carcinogenesis was comprehensively analysed using triplet sample sets of non-neoplastic epithelium, precursor lesion and invasive BTC. Immune-cell dynamics during IPN- and BilIN-associated carcinogenesis were subsequently compared.

RESULTS

Stromal CD3⁺ (P = 0.002), CD4⁺ (P = 0.007) and CD8⁺ (P < 0.001) T cells, CD20⁺ B cells (P = 0.008), MUM1⁺ plasma cells (P = 0.012) and CD163⁺ M2-like macrophages (P = 0.008) significantly decreased in IPN compared to non-tumorous biliary epithelium. Upon transition from IPN to invasive BTC, stromal CD68⁺ (P = 0.001) and CD163⁺ (P < 0.001) macrophages significantly increased. In contrast, BilIN-driven carcinogenesis was characterised by significant reduction of intraepithelial CD8⁺ T-lymphocytic infiltration from non-tumorous epithelium via BilIN (P = 0.008) to BTC (P = 0.004).

CONCLUSION

IPN and BilIN are immunologically distinct entities that undergo different immune-cell variations during biliary carcinogenesis. Intraepithelial CD8⁺ T-lymphocytic infiltration of biliary tissue decreased already at the IPN-precursor stage, whereas BilIN-associated carcinogenesis showed a slowly progressing reduction towards invasive carcinoma.

Similarities and differences among the Opisthorchiidae liver flukes: insights from Opisthorchis felineus

The foodborne liver trematode Opisthorchis felineus (Rivolta, 1884) is a member of the triad of phylogenetically related epidemiologically important Opisthorchiidae trematodes, which also includes O. viverrini (Poirier, 1886) and Clonorchis sinensis (Loos, 1907). Despite similarity in the life cycle, Opisthorchiidae liver flukes also have marked differences. Two species (O. viverrini and C. sinensis) are recognized as Group 1A biological carcinogens, whereas O. felineus belongs to Group 3A. In this review, we focus on these questions: Are there actual differences in carcinogenicity among these 3 liver fluke species? Is there an explanation for these differences? We provide a recent update of our knowledge on the liver fluke O. felineus and highlight its differences from O. viverrini and C. sinensis. In particular, we concentrate on differences in the climate of endemic areas, characteristics of the life cycle, the range of intermediate hosts, genomic and transcriptomic features of the pathogens, and clinical symptoms and morbidity of the infections in humans. The discussion of these questions can stimulate new developments in comparative studies on the pathogenicity of liver flukes and should help to identify species-specific features of opisthorchiasis and clonorchiasis pathogenesis.

Exploring the role of macrophages in determining the pathogenesis of liver fluke infection

The food-borne trematodes, Opisthorchis viverrini and Clonorchis sinensis, are classified as group 1 biological carcinogens: definitive causes of cancer. By contrast, infections with Fasciola hepatica, also a food-borne trematode of the phylum Platyhelminthes, are not carcinogenic. This review explores the premise that the differential activation of macrophages during infection with these food-borne trematodes is a major determinant of the pathological outcome of infection. Like most helminths, the latter stages of infection with all 3 flukes induce M2 macrophages, a phenotype that mediates the functional repair of tissue damaged by the feeding and migratory activities of the parasites. However, there is a critical difference in how the development of pro-inflammatory M1 macrophages is regulated during infection with these parasites. While the activation of the M1 macrophage phenotype is largely suppressed during the early stages of infection with F. hepatica, M1 macrophages predominate in the bile ducts following infection with O. viverrini and C. sinensis. The anti-microbial factors released by M1 macrophages create an environment conducive to mutagenesis, and hence the initiation of tumour formation. Subsequently, the tissue remodelling processes induced by the M2 macrophages promote the proliferation of mutated cells, and the expansion of cancerous tissue. This review will also explore the interactions between macrophages and parasite-derived signals, and their contributions to the stark differences in the innate immune responses to infection with these parasites.

Targeting tumor microenvironment for cholangiocarcinoma: Opportunities for precision medicine

•

CCA has a dismal prognosis, and it is usually diagnosed in advanced stage for which available treatments have limited efficacy.

•

CCA TME presents an abundant desmoplastic stroma and exhibits a high heterogeneity.

•

TME plays a central role in cancer development and in the resistance to treatments.

•

Treatments targeting the TME in association with cytotoxic agents could represent a promising therapeutic strategy.

Systemic treatments (e.g., chemotherapy and targeted therapies) have limited efficacy for patients with locally advanced – unresectable – and metastatic cholangiocarcinoma (CCA), with an overall survival of less than a year. Tumor microenvironment (TME) represents the ecosystem surrounding the tumor which comprises immune cells, fibroblasts, endothelial cells, and a wide range of soluble factors. CCA TME is characterized by an abundant desmoplastic stroma, exhibits a high heterogeneity and it plays a central role in cancer onset and progression. There is growing evidence suggesting that it is possible to target TME in association with other treatment modalities, such as cytotoxic chemotherapy or targeted therapies, paving the way to possible combination strategies with a synergistic effect. Herein, we describe the components of CCA TME – such as cancer-associated fibroblasts and other cells of pivotal importance - with their most relevant interactions, focusing on the preclinical rationale for the development of effective anticancer treatments.

Global changes in gene expression related to Opisthorchis felineus liver fluke infection reveal temporal heterogeneity of a mammalian host response

The food-borne trematode Opisthorchis felineus colonizes bile ducts of the liver of fish-eating mammals including humans. Among chronically infected individuals, this opisthorchiasis involves hepatobiliary problems, including chronic inflammation, periductal fibrosis, biliary intraepithelial neoplasia, and even cholangiocarcinoma. Despite numerous studies at the pathomorphological level, the systemic response and cellular pathogenesis of these disorders are not well studied.

To conduct in-depth research and to gain insights into the mechanism by which O. felineus infection causes precancerous liver lesions, we (i) applied a next-generation-sequencing–based technology (high-throughput mRNA sequencing) to identify differentially expressed genes in the liver of golden hamsters infected with O. felineus at 1 and 3 months postinfection and (ii) verified the most pronounced changes in gene expression by western blotting and immunohistochemistry.

A total of 2151 genes were found to be differentially expressed between uninfected and infected hamsters (“infection” factor), whereas 371 genes were differentially expressed when we analyzed “time × infection” interaction. Cluster analysis revealed that sets of activated genes of cellular pathways were different between acute (1 month postinfection) and chronic (3 months postinfection) opisthorchiasis. This enriched KEGG pathways were “Cell adhesion molecules”, “Hippo signaling”, “ECM-receptor interaction”, “Cell cycle”, “TGF-beta”, and “P53 signaling”. Moreover, epithelial–mesenchymal transition was the most enriched (q-value = 2.2E-07) MSigDB hallmark in the set of differentially expressed genes of all O. felineus–infected animals. Transcriptomic data were supported by the results of western blotting and immunohistochemistry revealing the upregulation of vimentin, N-cadherin, and α-smooth muscle actin postinfection.

Our data expand knowledge about global changes in gene expression in the O. felineus–infected host liver and contribute to understanding the biliary neoplasia associated with the liver fluke infection.

•

A total of 2151 genes were found to be differentially expressed during the infection.

•

Epithelial-Mesenchymal Transition was the most enriched process in the infected animals.

•

Different pathways were activated between acute and chronic opisthorchiasis.

Tumor-associated macrophages promote cholangiocarcinoma progression via exosomal Circ_0020256

This study investigated the exosomal circular RNAs (CircRNAs) produced by tumor-associated macrophages and delivered into the microenvironment of cholangiocarcinoma cells in order to use them as molecular targets for clinical therapy. Tumor-associated M2 macrophages (TAMs) were induced from THP-1 cells and identified by flow cytometry. The TAM-secreted exosomes were isolated from conditioned medium and a CircRNA microarray assay was performed to identify CircRNAs that were uniquely expressed in the isolated exosomes. Circ_0020256 was especially identified based on having the highest differential expression level among all of the CircRNA candidates. In vitro and in vivo experiments were performed to assess the effects of TAMs, exosomes, and Circ_0020256 on the growth and migration of cholangiocarcinoma (CCA) cells. The induced TAMs promoted the proliferation, migration, and invasion of CCA cells and those effects were mediated by exosomes secreted by the TAMs. In CCA cells (RBE and HCCC-9810), Circ_0020256 significantly promoted cellular activity by interacting with its intra-cellular microRNA target, miR-432-5p. In contrast, overexpression of transcription factor E2F3 in CCA cells restored the CCA cellular activities that were inhibited by miR-432-5p. On the other hand, treatment with small interference RNA (siRNA) for Circ_0020256 inhibited CCA cell proliferation, migration, and invasion both in vitro and in vivo. In conclusion, Circ_0020256 in TAM-secreted exosomes promoted the proliferation, migration, and invasion of CCA cells, and that promotional activity was regulated via a Circ_0020256/miR-432-5p/E2F3 axis.

Cholangiocarcinoma: what are the most valuable therapeutic targets - cancer-associated fibroblasts, immune cells, or beyond T cells?

INTRODUCTION

CCAs are dense and desmoplastic tumors with an abundant tumor microenviroment (TME). The evolving TME is characterized by reciprocal interactions between cancer cells and their environment and is essential in facilitating tumor progression. The TME has nonimmune and immune components. Nonimmune cell types include cancer-associated fibroblasts (CAFs) and endothelial cells accompanying tumor angiogenesis. Immune cell types include elements of the innate and adaptive immune response, and can have pro-tumor or antitumor roles. The TME can shape treatment response and resistance. Therefore, elements of the TME are attractive therapeutic targets. TME targeting therapies have been evaluated in preclinical and clinical studies but only a small subset of patients has a meaningful response.

AREAS COVERED

We discuss the TME components and potential TME targeting strategies. Literature search was performed on PubMed and ClinicalTrials.gov until October 2021.

EXPERT OPINION

Elucidating the CCA TME is essential for developing effective treatment strategies. Preclinical models that recapitulate the disease (such as organoids) are important tools in uncovering the intricate cross talk in the CCA TME. Characterization of patient-derived specimens using multi-omic and single-omic technologies can dissect the cellular interplay in the CCA TME, which can guide development of effective treatment strategies and identify biomarkers for patient stratification.

Cellular based immunotherapy for primary liver cancer

Primary liver cancer (PLC) is a common malignancy with high morbidity and mortality. Poor prognosis and easy recurrence on PLC patients calls for optimizations of the current conventional treatments and the exploration of novel therapeutic strategies. For most malignancies, including PLC, immune cells play crucial roles in regulating tumor microenvironments and specifically recognizing tumor cells. Therefore, cellular based immunotherapy has its instinctive advantages in PLC therapy as a novel therapeutic strategy. From the active and passive immune perspectives, we introduced the cellular based immunotherapies for PLC in this review, covering both the lymphoid and myeloid cells. Then we briefly review the combined cellular immunotherapeutic approaches and the existing obstacles for PLC treatment.

Tumor-associated macrophages in cholangiocarcinoma: complex interplay and potential therapeutic target

Cholangiocarcinoma (CCA) is an aggressive and multifactorial malignancy of the biliary tract. The carcinogenesis of CCA is associated with genomic and epigenetic abnormalities, as well as environmental effects. However, early clinical diagnosis and reliable treatment strategies of CCA remain unsatisfactory. Multiple compartments of the tumor microenvironment significantly affect the progression of CCA. Tumor-associated macrophages (TAMs) are a type of plastic immune cells that are recruited and activated in the CCA microenvironment, especially at the tumor invasive front and perivascular sites. TAMs create a favorable environment that benefits CCA growth by closely interacting with CCA cells and other stromal cells via releasing multiple protumor factors. In addition, TAMs exert immunosuppressive and antichemotherapeutic effects, thus intensifying the malignancy. Targeting TAMs may provide an improved understanding of, and novel therapeutic approaches for, CCA. This review focuses on revealing the interplay between TAMs and CCA.

The Emerging Role of Immunotherapy in Intrahepatic Cholangiocarcinoma

Biliary tract cancer, and intrahepatic cholangiocarcinoma (iCC) in particular, represents a rather uncommon, highly aggressive malignancy with unfavorable prognosis. Therapeutic options remain scarce, with platinum-based chemotherapy is being considered as the gold standard for the management of advanced disease. Comprehensive molecular profiling of tumor tissue biopsies, utilizing multi-omics approaches, enabled the identification of iCC’s intratumor heterogeneity and paved the way for the introduction of novel targeted therapies under the scope of precision medicine. Yet, the unmet need for optimal care of patients with chemo-refractory disease or without targetable mutations still exists. Immunotherapy has provided a paradigm shift in cancer care over the past decade. Currently, immunotherapeutic strategies for the management of iCC are under intense research. Intrinsic factors of the tumor, including programmed death-ligand 1 (PD-L1) expression and mismatch repair (MMR) status, are simply the tip of the proverbial iceberg with regard to resistance to immunotherapy. Acknowledging the significance of the tumor microenvironment (TME) in both cancer growth and drug response, we broadly discuss about its diverse immune components. We further review the emerging role of immunotherapy in this rare disease, summarizing the results of completed and ongoing phase I–III clinical trials, expounding current challenges and future directions.

CD44 modulates metabolic pathways and altered ROS-mediated Akt signal promoting cholangiocarcinoma progression

CD44 is a transmembrane glycoprotein, the phosphorylation of which can directly trigger intracellular signaling, particularly Akt protein, for supporting cell growth, motility and invasion. This study examined the role of CD44 on the progression of Cholangiocarcinoma (CCA) using metabolic profiling to investigate the molecular mechanisms involved in the Akt signaling pathway. Our results show that the silencing of CD44 decreases Akt and mTOR phosphorylation resulting in p21 and Bax accumulation and Bcl-2 suppression that reduces cell proliferation. Moreover, an inhibition of cell migration and invasion regulated by CD44. Similarly, the silencing of CD44 showed an alteration in the epithelial-mesenchymal transition (EMT), e.g. an upregulation of E-cadherin and a downregulation of vimentin, and the reduction of the matrix metalloproteinase (MMP)-9 signal. Interestingly, a depletion of CD44 leads to metabolic pathway changes resulting in redox status modification and Trolox (anti-oxidant) led to the recovery of the cancer cell functions. Based on our findings, the regulation of CCA progression and metastasis via the redox status-related Akt signaling pathway depends on the alteration of metabolic profiling synchronized by CD44.

Sulfasalazine modifies metabolic profiles and enhances cisplatin chemosensitivity on cholangiocarcinoma cells in in vitro and in vivo models

Background

Sulfasalazine (SSZ) is widely known as an xCT inhibitor suppressing CD44v9-expressed cancer stem-like cells (CSCs) being related to redox regulation. Cholangiocarcinoma (CCA) has a high recurrence rate and no effective chemotherapy. A recent report revealed high levels of CD44v9-positive cells in CCA patients. Therefore, a combination of drugs could prove a suitable strategy for CCA treatment via individual metabolic profiling.

Methods

We examined the effect of xCT-targeted CD44v9-CSCs using sulfasalazine combined with cisplatin (CIS) or gemcitabine in CCA in vitro and in vivo models and did NMR-based metabolomics analysis of xenograft mice tumor tissues.

Results

Our findings suggest that combined SSZ and CIS leads to a higher inhibition of cell proliferation and induction of cell death than CIS alone in both in vitro and in vivo models. Xenograft mice showed that the CD44v9-CSC marker and CK-19-CCA proliferative marker were reduced in the combination treatment. Interestingly, different metabolic signatures and significant metabolites were observed in the drug-treated group compared with the control group that revealed the cancer suppression mechanisms.

Conclusions

SSZ could improve CCA therapy by sensitization to CIS through killing CD44v9-positive cells and modifying the metabolic pathways, in particular tryptophan degradation (i.e., kynurenine pathway, serotonin pathway) and nucleic acid metabolism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40170-021-00249-6.

Targeting the tumor microenvironment in cholangiocarcinoma: implications for therapy

Introduction: Cholangiocarcinoma (CCA) is a rare, deadly cancer that is characterized by an abundant desmoplastic stroma. Late diagnoses and limited available effective treatments are major problems with this malignancy. Targeting of the tumor microenvironment (TME) has emerged as a potential therapeutic strategy.Areas covered: In this review, we describe the role of the various compartments of the TME in CCA and focus on the preclinical rationale for the development of innovative therapies. Relevant literature was identified by a PubMed search covering the last decade (2010-2020).Expert opinion: Low efficacy of surgery and cytotoxic chemotherapy emphasizes the need for new therapeutic strategies and companion biomarkers. Single-cell RNA sequencing of the stroma is yielding a critical functional characterization of TME in CCA and is paving the way for immunotherapies and cancer-associated fibroblast and extracellular matrix-oriented treatments. We believe that the development of treatments targeting the components of the TME will produce the best results if in combination with cytotoxic chemotherapy. Biomarkers should be developed to define the patient population of interest for each combination strategy.

New insights on the role of vascular endothelial growth factor in biliary pathophysiology

The family of vascular endothelial growth factors (VEGFs) includes 5 members (VEGF-A to -D, and placenta growth factor), which regulate several critical biological processes. VEGF-A exerts a variety of biological effects through high-affinity binding to tyrosine kinase receptors (VEGFR-1, -2 and -3), co-receptors and accessory proteins. In addition to its fundamental function in angiogenesis and endothelial cell biology, VEGF/VEGFR signalling also plays a role in other cell types including epithelial cells. This review provides an overview of VEGF signalling in biliary epithelial cell biology in both normal and pathologic conditions. VEGF/VEGFR-2 signalling stimulates bile duct proliferation in an autocrine and paracrine fashion. VEGF/VEGFR-1/VEGFR-2 and angiopoietins are involved at different stages of biliary development. In certain conditions, cholangiocytes maintain the ability to secrete VEGF-A, and to express a functional VEGFR-2 receptor. For example, in polycystic liver disease, VEGF secreted by cystic cells stimulates cyst growth and vascular remodelling through a PKA/RAS/ERK/HIF1α-dependent mechanism, unveiling a new level of complexity in VEFG/VEGFR-2 regulation in epithelial cells. VEGF/VEGFR-2 signalling is also reactivated during the liver repair process. In this context, pro-angiogenic factors mediate the interactions between epithelial, mesenchymal and inflammatory cells. This process takes place during the wound healing response, however, in chronic biliary diseases, it may lead to pathological neo-angiogenesis, a condition strictly linked with fibrosis progression, the development of cirrhosis and related complications, and cholangiocarcinoma. Novel observations indicate that in cholangiocarcinoma, VEGF is a determinant of lymphangiogenesis and of the immune response to the tumour. Better insights into the role of VEGF signalling in biliary pathophysiology might help in the search for effective therapeutic strategies.

Intrahepatic cholangiocarcinoma induced M2-polarized tumor-associated macrophages facilitate tumor growth and invasiveness

BACKGROUND

M2-polarized tumor-associated macrophages (M2-TAMs) have been shown to correlate with the progression of various cancers, including intrahepatic cholangiocarcinoma (ICC). However, the interactions and mechanism between M2 macrophages and ICC are not completely clear. We aimed to clarify whether M2 macrophages promote the malignancy of ICC and its mechanism.

METHODS

Two progressive murine models of ICC were used to evaluate the alterations in different macrophage populations and phenotypes. Furthermore, we assessed M2 macrophage infiltration in 48 human ICC and 15 normal liver samples. The protumor functions and the underlying molecular mechanisms of M2 macrophages in ICC were investigated in an in vitro coculture system.

RESULTS

We found that the number of M2 macrophages was significantly higher in ICC tissues than in normal bile ducts in the two murine models. M2 macrophage infiltration was highly increased in peritumoral compared with intratumoral regions and normal liver (p < 0.01). ICC cells induced macrophages to differentiate into the M2-TAM phenotype, and coculture with these M2 macrophages promoted ICC cell proliferation, invasion and epithelial-mesenchymal transition (EMT) in vitro. Mechanistically, M2-TAM-derived IL-10 promoted the malignant properties of ICC cells through STAT3 signaling. Furthermore, blockade of IL-10/STAT3 signaling partly rescued the effects of M2 macrophages on ICC.

CONCLUSION

Our results indicated that M2-polarized macrophages induced by ICC promote tumor growth and invasiveness through IL-10/STAT3-induced EMT and might be a potential therapeutic target for ICC.

FCGR1A Serves as a Novel Biomarker and Correlates With Immune Infiltration in Four Cancer Types

BACKGROUND

FCGR1A encodes a protein that plays an important role in the immune response. The prognostic impact and immune infiltration of FCGR1A in heterogeneous cancers remain unclear.

METHODS

Differential expression of FCGR1A between tumor and normal tissues and the discrepancies in overall survival (OS) among diverse cancer types were performed by Gene Expression Profiling Interactive Analysis. The correlation between FCGR1A and immune cells or gene marker sets of immune infiltrates was analyzed via Tumor Immune Estimation Resource (TIMER). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and protein-to-protein interaction (PPI) network were used to explore the function and related genes of FCGR1A. The relationships among these genes were further analyzed by TIMER.

RESULTS

FCGR1A is highly expressed in various cancer types. FCGR1A was significantly correlated with the OS of cervical and endocervical cancer (CESC), cholangiocarcinoma (CHOL), kidney renal clear cell carcinoma (KIRC), and skin cutaneous melanoma (SKCM) (P < 0.05). High expression of FCGR1A meant a better prognosis besides KIRC. FCGR1A showed significant differences at different stages of KIRC and SKCM (P < 0.05). Furthermore, FCGR1A was notably associated with infiltrating levels of CD4+ T cells, CD8+ T cells, B cells, macrophages, neutrophils, and dendritic cells in the four cancers (P < 0.05). FCGR1A also showed close relevance with different immune gene markers. The copy number variation of FCGR1A significantly influenced the abundance of immune infiltration in KIRC and SKCM. GO, KEGG analysis, and PPI network analysis revealed that FCGR1A is involved in many pathophysiological processes and was most related to FCGR3A. And this gene indicated highly significant positive correlations with FCGR1A in four cancers.

CONCLUSION

FCGR1A may be a potential prognostic biomarker and related to immune infiltration levels in diverse cancers, especially in CESC, CHOL, KIRC, and SKCM. Besides, FCGR1A may be involved in the activation, regulation, or induction of immune cells and diverse physiological and pathological processes.

Tumor microenvironment in primary liver tumors: A challenging role of natural killer cells

In the last years, several studies have been focused on elucidate the role of tumor microenvironment (TME) in cancer development and progression. Within TME, cells from adaptive and innate immune system are one of the main abundant components. The dynamic interactions between immune and cancer cells lead to the activation of complex molecular mechanisms that sustain tumor growth. This important cross-talk has been elucidate for several kind of tumors and occurs also in patients with liver cancer, such as hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (iCCA). Liver is well-known to be an important immunological organ with unique microenvironment. Here, in normal conditions, the rich immune-infiltrating cells cooperate with non-parenchymal cells, such as liver sinusoidal endothelial cells and Kupffer cells, favoring self-tolerance against gut antigens. The presence of underling liver immunosuppressive microenvironment highlights the importance to dissect the interaction between HCC and iCCA cells with immune infiltrating cells, in order to understand how this cross-talk promotes tumor growth. Deeper attention is, in fact, focused on immune-based therapy for these tumors, as promising approach to counteract the intrinsic anti-tumor activity of this microenvironment. In this review, we will examine the key pathways underlying TME cell-cell communications, with deeper focus on the role of natural killer cells in primary liver tumors, such as HCC and iCCA, as new opportunities for immune-based therapeutic strategies.

Molecular and Immunological Characterization of Biliary Tract Cancers: A Paradigm Shift Towards a Personalized Medicine

Biliary tract cancers (BTCs) are a group of rare cancers that account for up to 3-5% of cancer patients worldwide. BTCs include cholangiocarcinoma (CCA), gallbladder cancer (GBC), and ampulla of Vater cancer (AVC). They are frequently diagnosed at an advanced stage when the disease is often found disseminated. A late diagnosis highly compromises surgery, the only potentially curative option. Current treatment regimens include a combination of chemotherapeutic drugs gemcitabine with cisplatin that have a limited efficiency since more than 50% of patients relapse in the first year. More recently, an inhibitor of fibroblast growth factor receptor 2 (FGFR2) was approved as a second-line treatment, based on the promising results from the NCT02924376 clinical trial. However, novel secondary treatment options are urgently needed. Recent molecular characterization of CCA and GBC highlighted the molecular heterogeneity, etiology, and epidemiology in BTC development and lead to the classification of the extrahepatic CCA into four types: metabolic, proliferating, mesenchymal, and immune type. Differences in the immune infiltration and tumor microenvironment (TME) have been described as well, showing that only a small subset of BTCs could be classified as an immune "hot" and targeted with the immunotherapeutic drugs. This recent evidence has opened a way to new clinical trials for BTCs, and new drug approvals are highly expected by the medical community.

Characterization of Gut Microbiota, Bile Acid Metabolism, and Cytokines in Intrahepatic Cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC), a type of bile duct cancer, has a high mortality rate. Gut microbiota, bile acid (BA) metabolism, and cytokines have not been characterized in patients with ICC, and better noninvasive diagnostic approaches for ICC are essential to be established. Therefore, in this study we aimed to improve our understanding of changes in gut microbiota, BA metabolism, and cytokines in patients with ICC. We found that the α-diversities and β-diversities of ICC were highest and that the abundances of four genera (Lactobacillus, Actinomyces, Peptostreptococcaceae, and Alloscardovia) were increased in patients with ICC compared with those in patients with hepatocellular carcinoma or liver cirrhosis and in healthy individuals. The glycoursodeoxycholic acid and tauroursodeoxycholic acid (TUDCA) plasma-stool ratios were obviously increased in patients with ICC. Furthermore, the genera Lactobacillus and Alloscardovia that were positively correlated with TUDCA plasma-stool ratios were combined to discriminate ICC from the other three diseases. Vascular invasion (VI) frequently led to a poor prognosis in patients with ICC. Compared with patients with ICC without VI, patients with VI had a greater abundance of the family Ruminococcaceae, increased levels of plasma interleukin (IL)-4 and six conjugated BAs, and decreased levels of plasma IL-6 and chenodeoxycholic acid. A positive correlation between plasma taurocholic acid and IL-4 was observed in patients with ICC. Plasma TUDCA was negatively correlated with the abundance of the genus Pseudoramibacter and the survival time of patients with ICC, but had no effect on tumor size, as determined in two murine tumor models. Conclusion: In this study, we identified some biomarkers, including gut microbiota, BAs and inflammatory cytokines, for the diagnosis of ICC and prediction of VI in patients with ICC.

Immune contexture of cholangiocarcinoma

PURPOSE OF REVIEW

Considering the failure of standard treatments (i.e. surgery, radiotherapy, chemotherapy) in treating cholangiocarcinoma (CCA), introduction of alternative interventions is urgently needed. During the past 2 decades, discoveries of the mechanisms of cancer immunosurveillance and tumor immune evasion have precipitated the emergence and clinical approval of immunotherapies in multiple malignant indications. Interest in their introduction for the care of CCA is recent and several immunotherapeutic approaches are undergoing a clinical evaluation. Undoubtedly, their efficient application, as monotherapy or in combination regimens, will rely on a deeper understanding of CCA immune contexture.

RECENT FINDINGS

CCA cells appeared very potent in recruiting protumorigenic cells and shaping an immunosuppressive microenvironment. Elevated densities of several immune cells with immunoinhibitory activities within the malignant bed have been associated with poor prognosis in patients. Particularly, macrophages and neutrophils (especially in their alternatively activated phenotype) were pointed out for their role in cancer progression. Dendritic cells were described as ineffective in priming CCA-specific T-cell responses.

SUMMARY

Quantitative and qualitative assessment of the innate and adaptive immune compartments of the CCA immune contexture, as well as their prognostic value, will benefit to the development of improved immunotherapeutic strategies.

LRRK2 Is Associated with Recurrence-Free Survival in Intrahepatic Cholangiocarcinoma and Downregulation of LRRK2 Suppresses Tumor Progress In Vitro

BACKGROUND

The leucine-rich repeat kinase 2 (LRRK2) gene was confirmed to be associated with a variety of diseases, while the physiological function of LRRK2 remains poorly understood. Intrahepatic cholangiocarcinoma (ICC) has over the last 10 years become the focus of increasing concern largely. Despite recent progress in the standard of care and management options for ICC, the prognosis for this devastating cancer remains dismal.

METHODS

A total of 57 consecutive ICC patients who underwent curative hepatectomy in our institution were included in our study. We conduct a retrospective study to evaluate the prognostic value of LRRK2 in ICC after resection. The mechanism of LRRK2 in ICC development was also investigated in vitro.

RESULTS

All patients were divided into two groups according to the content of LRRK2 in the tissue microarray blocks via immunohistochemistry: low-LRRK2 group (n = 33) and high-LRRK2 group (n = 24). The recurrence-free survival rate of high-LRRK2 group was significantly poorer than that of low-LRRK2 group (P = 0.010). Multivariate analysis showed high-LRRK2 was the prognostic factor for recurrence-free survival after hepatectomy. We demonstrated that downregulation of LRRK2 depressed the proliferation and metastasis of ICC cells in vitro.

CONCLUSION

We provide evidence that LRRK2 was an independent prognostic factor for ICC in humans by participating in the proliferation and metastasis of ICC cells.

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.

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.

Opisthorchis felineus infection provokes time-dependent accumulation of oxidative hepatobiliary lesions in the injured hamster liver

Opisthorchiasis caused by food-borne trematode Opisthorchis felineus is a substantial public health problem, with 17 million persons infected worldwide. This chronic disease is associated with hepatobiliary inflammation, cholangiocyte dysplasia, cholangiofibrosis, intraepithelial neoplasia, and even cholangiocarcinoma among chronically infected individuals. To provide first insights into the mechanism by which O. felineus infection causes precancerous liver lesions, we investigated the level of oxidative stress (lipid peroxidation byproducts and 8-hydroxy-2′-deoxyguanosine) as well as the time course profiles of chronic inflammation and fibrogenesis markers in the dynamics of opisthorchiasis from 1 month to 1.5 years postinfection in an experimental model based on golden hamsters Mesocricetus auratus. For the first time, we showed that O. felineus infection provokes time-dependent accumulation of oxidative hepatobiliary lesions in the injured liver of hamsters. In particular, over the course of infection, lipid peroxidation byproducts 4-hydroxynonenal and malondialdehyde were upregulated; these changes in general correlate with the dynamics of hepatic histopathological changes. We detected macrophages with various immunophenotypes and elevated levels of CD68, COX2, and CD163 in the O. felineus–infected animals. Meanwhile, there was direct time-dependent elevation of TNF-α (R = 0.79; p < 0.001) and CD163 protein levels (R = 0.58; p = 0.022). We also provide quantitative data about epithelial hyperplasia marker CK7 and a marker of myofibroblast activation (α smooth muscle actin). Our present data provide first insights into the histopathological mechanism by which O. felineus infection causes liver injuries. These findings support the inclusion of O. felineus in Group 1 of biological carcinogens.

The tumour microenvironment and immune milieu of cholangiocarcinoma

Tumour microenvironment is a complex, multicellular functional compartment that, particularly when assembled as an abundant desmoplastic reaction, may profoundly affect the proliferative and invasive abilities of epithelial cancer cells. Tumour microenvironment comprises not only stromal cells, mainly cancer-associated fibroblasts, but also immune cells of both the innate and adaptive system (tumour-associated macrophages, neutrophils, natural killer cells, and T and B lymphocytes), and endothelial cells. This results in an intricate web of mutual communications regulated by an extensively remodelled extracellular matrix, where the tumour cells are centrally engaged. In this regard, cholangiocarcinoma, in particular the intrahepatic variant, has become the focus of mounting interest in the last years, largely because of the lack of effective therapies despite its rising incidence and high mortality rates worldwide. On the other hand, recent studies in pancreatic cancer, which similarly to cholangiocarcinoma, is highly desmoplastic, have argued against a tumour-promoting function of the tumour microenvironment. In this review, we will discuss recent developments concerning the role of each cellular population and their multifaceted interplay with the malignant biliary epithelial counterpart. We ultimately hope to provide the working knowledge on how their manipulation may lead to a therapeutic gain in cholangiocarcinoma.

Intrahepatic Cholangiocarcinoma: Continuing Challenges and Translational Advances

Intrahepatic cholangiocarcinoma (iCCA) has over the last 10-20 years become the focus of increasing concern, largely due to its rising incidence and high mortality rates worldwide. The significant increase in mortality rates from this primary hepatobiliary cancer, particularly over the past decade, has coincided with a rapidly growing interest among clinicians, investigators, and patient advocates to seek greater mechanistic insights and more effective biomarker-driven targeted approaches for managing and/or preventing this challenging liver cancer. In addition to discussing challenges posed by this aggressive cancer, this review will emphasize recent epidemiological, basic, and translational research findings for iCCA. In particular, we will highlight emerging demographic changes and evolving risk factors, the critical role of the tumor microenvironment, extracellular vesicle biomarkers and therapeutics, intertumoral and intratumoral heterogeneity, and current and emerging targeted therapies regarding iCCA. Specifically, recent evidence linking non-bile duct medical conditions, such as nonalcoholic fatty liver disease and nonspecific cirrhosis, to intrahepatic cholangiocarcinogenesis together with geographic and ethnic variation will be assessed. Recent developments concerning the roles played by transforming growth factor-β and platelet-derived growth factor D in driving the recruitment and expansion of cancer-associated myofibroblasts within cholangiocarcinoma (CCA) stroma as well as their therapeutic implications will also be discussed. In addition, the potential significance of extracellular vesicles as bile and serum biomarkers and therapeutic delivery systems for iCCA will be described. An integrated systems approach to classifying heterogeneous iCCA subtypes will be further highlighted, and recent clinical trials and emerging targeted therapies will be reviewed, along with recommendations for future translational research opportunities. Established international CCA networks are now facilitating collaborations aimed at advancing iCCA translational and clinical research.

Fucosyl-Agalactosyl IgG₁ Induces Cholangiocarcinoma Metastasis and Early Recurrence by Activating Tumor-Associated Macrophage

Concern over roles of serum IgG agalactosylation in chronic inflammatory diseases has been mounting for years but less touched in cancers. The present study addressed the underlying role of agalactosylated IgG beyond tumorigenesis. Liquid-chromatography-tandem mass spectrometry was leveraged for the analysis of IgG₁ and IgG₂N-glycomes. We found that a high percentage of serum fucosyl-agalactosyl IgG₁ (IgG₁-G0F) in patients with cholangiocarcinoma was associated with poor tumor differentiation and tumor metastasis. Results from Kaplan–Meier analyses and a stepwise Cox regression analysis showed that patients with serum IgG₁-G0F ≥40% were highly correlated with poor recurrence-free survivals and overall survivals. Interestingly, patients with cholangiocarcinoma whose serum IgG₁-G0F ≥40% had more CD163+ tumor-associated macrophages in cancerous tissues than adjacent non-cancerous counterparts. In vitro assays revealed that agalactosylated IgG upregulated tumor-associated macrophage markers CD163 and CD204 in human U-937 cells and peripheral macrophages. Moreover, a positive and a negative feedback loop of transforming growth factor-β1 and interferon-γ, respectively, on IgG agalactosylation was identified using hybridoma cells and verified in sera of the patients. In conclusion, agalactosylated IgG activates tumor-associated macrophages, thereby promoting tumor metastasis and recurrence of cholangiocarcinoma.

The role of tumour microenvironment: a new vision for cholangiocarcinoma

Cholangiocarcinoma (CCA) is a relatively rare malignant and lethal tumour derived from bile duct epithelium and the morbidity is now increasing worldwide. This disease is difficult to diagnose at its inchoate stage and has poor prognosis. Therefore, a clear understanding of pathogenesis and major influencing factors is the key to develop effective therapeutic methods for CCA. In previous studies, canonical correlation analysis has demonstrated that tumour microenvironment plays an intricate role in the progression of various types of cancers including CCA. CCA tumour microenvironment is a dynamic environment consisting of authoritative tumour stromal cells and extracellular matrix where tumour stromal cells and cancer cells can thrive. CCA stromal cells include immune and non‐immune cells, such as inflammatory cells, endothelial cells, fibroblasts, and macrophages. Likewise, CCA tumour microenvironment contains abundant proliferative factors and can significantly impact the behaviour of cancer cells. Through abominably intricate interactions with CCA cells, CCA tumour microenvironment plays an important role in promoting tumour proliferation, accelerating neovascularization, facilitating tumour invasion, and preventing tumour cells from organismal immune reactions and apoptosis. This review summarizes the recent research progress regarding the connection between tumour behaviours and tumour stromal cells in CCA, as well as the mechanism underlying the effect of tumour stromal cells on the growth of CCA. A thorough understanding of the relationship between CCA and tumour stromal cells can shed some light on the development of new therapeutic methods for treating CCA.

Resveratrol interrupts the pro-invasive communication between cancer associated fibroblasts and cholangiocarcinoma cells

Cholangiocarcinoma (CCA), the cancer arising from the epithelial cells of bile ducts, is a prototype of inflammatory-driven cancer. Cytokines released by cancer associated fibroblasts (CAFs) play a pivotal role in CCA progression, driving the epigenetic Epithelial-to-Mesenchymal transition and the growth and metastasization of CCA cells. Consistently, the conditioned medium from CCA-derived CAFs further stimulated the secretion of IL-6, and to a lesser extent of IL-8, by CCA cells. CCA has a poor prognosis, because of late diagnosis and of high resistance to radio- and chemo-therapy of CCA cells. Targeting the CAFs and their secretion could be an alternative option. We found that while IL-6 indeed promoted the cell migration of invasive CCA cells, the nutraceutical Resveratrol strongly counteracted this effect both in CCA cells and in immortalized cholangiocytes. More importantly, here we show that Resveratrol has the potential to abrogate the secretion of IL-6 by CAFs. While the conditioned medium from CAFs strongly induced IL-6 mediated motility of CCA cells, the conditioned medium from CAFs pre-treated with Resveratrol completely halted cancer cell motility and reverted the N-to E-cadherin switch in migrating cells. This effect was associated with stimulation of autophagy in the cancer cells. This is the first demonstration that CAFs secretory products directly affect the regulation of autophagy and consequently the behavior of CCA cells, and that a nutraceutical may revert the malignant phenotype of cancer cells by acting on CAFs metabolism and secretion.

Prognostic biomarkers for cholangiocarcinoma and their clinical implications

INTRODUCTION

Cholangiocarcinoma (CCA) is a poorly prognostic cancer with limited treatment options. Most patients have unresectable tumors when they are diagnosed and the chemotherapies provided are of limited benefit. Prognostic markers are therefore necessary to predict the disease outcome, risk of relapse, or to suggest the best treatment option. Areas covered: This article provides an up-to-date review of biomarkers with promising characteristics to be prognostic markers for CCA reported in the past 5 years. The biomarkers are sub-classified into tissue and serum markers. Proteins, RNAs, peripheral blood cells etc., that are associated with aggressive phenotypes, signal pathways, chemo-drug resistance, and those that reflect the survival time of CCA patients are evaluated for their prognostic prediction values. Expert commentary: CCAs are heterogeneous tumors of different histo-pathological subtypes and genetic influences and, therefore, potential markers should be validated in larger collectives with varied epidemiological backgrounds. A systematic review and meta-analysis should be done to clarify the impact of the reported biomolecules for their potential prognostic values. Non- or low-invasive sample collections, as well as the simple and affordable determination methods, should be constructed to make the prognostic biomarkers available in clinical practice.

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.

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.

The microRNA-15a-PAI-2 axis in cholangiocarcinoma-associated fibroblasts promotes migration of cancer cells

BACKGROUND

Cholangiocarcinoma (CCA) has an abundance of tumor stroma which plays an important role in cancer progression via tumor-promoting signals. This study aims to explore the microRNA (miRNA) profile of CCA-associated fibroblasts (CCFs) and the roles of any identified miRNAs in CCA progression.

METHODS

miRNA expression profiles of CCFs and normal skin fibroblasts were compared by microarray. Identified downregulated miRNAs and their target genes were confirmed by real-time PCR. Their binding was confirmed by a luciferase reporter assay. The effects of conditioned-media (CM) of miRNA mimic- and antagonist-transfected CCFs were tested in CCA migration in wound healing assays. Finally, the levels of miRNA and their target genes were examined by real-time PCR and immunohistochemistry in clinical CCA samples.

RESULTS

miR-15a was identified as a downregulated miRNA in CCFs. Moreover, PAI-2 was identified as a novel target gene of miR-15a. Recombinant PAI-2 promoted migration of CCA cells. Moreover, CM from miR-15a mimic-transfected CCFs suppressed migration of CCA cells. Lower expression of miR-15a and higher expression of PAI-2 were observed in human CCA samples compared with normal liver tissues. Importantly, PAI-2 expression correlated with poor prognosis in CCA patients.

CONCLUSIONS

These findings highlight the miR-15a/PAI-2 axis as a potential therapeutic target in CCA patients.

Opisthorchiasis-Induced Cholangiocarcinoma: How Innate Immunity May Cause Cancer

Innate, inflammatory responses towards persistent Opisthorchis viverrini (OV) infection are likely to contribute to the development of cholangiocarcinoma (CCA), a liver cancer that is rare in the West but prevalent in Greater Mekong Subregion countries in Southeast Asia. Infection results in the infiltration of innate immune cells into the bile ducts and subsequent activation of inflammatory immune responses that fail to clear OV but instead may damage local tissues within the bile ducts. Not all patients infected with OV develop CCA, and so tumourigenesis may be dependent on multiple factors including the magnitude of the inflammatory response that is activated in infected individuals. The purpose of this review is to summarize how innate immune responses may promote tumourigenesis following OV infection and if such responses can be used to predict CCA onset in OV-infected individuals. It also hypothesizes on the role that Helicobacterspp., which are associated with liver fluke infections, may play in activation of the innate the immune system to promote tissue damage and persistent inflammation leading to CCA.

Establishment of cholangiocarcinoma cell lines from patients in the endemic area of liver fluke infection in Thailand

Cholangiocarcinoma is a rare type of cancer which is an increasingly discernible health threat. The disease is usually very difficult in diagnosis and various treatment modalities are typically not effective. Cholangiocarcinoma is a complex and very heterogeneous malignancy characterized by tumor location, different risk factors, molecular profiling, and prognosis. Cancer cell lines represent an important tool for investigation in various aspects of tumor biology and molecular therapeutics. We established two cell lines, KKU-452 and KKU-023, which were derived from patients residing in the endemic area of liver fluke infection in Thailand. Both of tumor tissues have gross pathology of perihilar and intrahepatic mass-forming cholangiocarcinoma. Two cell lines were characterized for their biological, molecular and genetic properties. KKU-452 and KKU-023 cells are both adherent cells with epithelium morphology, but have some differences in their growth pattern (a doubling time of 17.9 vs 34.8 h, respectively) and the expression of epithelial bile duct markers, CK7 and CK19. Cytogenetic analysis of KKU-452 and KKU-023 cells revealed their highly complex karyotypes; hypertriploid and hypotetraploid, respectively, with multiple chromosomal aberrations. Both cell lines showed mutations in p53 but not in KRAS. KKU-452 showed a very rapid migration and invasion properties in concert with low expression of E-cadherin and high expression of N-cadherin, whereas KKU-023 showed opposite characters. KKU-023, but not KKU-452, showed in vivo tumorigenicity in xenografted nude mice. Those two established cholangiocarcinoma cell lines with unique characters may be valuable for better understanding the process of carcinogenesis and developing new therapeutics for the patients

LncRNA-MALAT1 Promotes Angiogenesis of Thyroid Cancer by Modulating Tumor-Associated Macrophage FGF2 Protein Secretion

Tumor-associated macrophages (TAMs) in the tumor microenvironment have been associated with enhanced tumor progression. In this study, we investigated the role and molecular mechanisms of MALAT1 in TAMs derived from thyroid cancer. The expression of MALAT1 and FGF2 in thyroid cancer tissues and cells were measured by quantitative real-time PCR and Western blot. TAMs were transfected with indicated constructs. Then the culture medium (CM) from TAMs was harvested for assay. Secreted FGF2 protein levels and TNF-α, IL-12, and IL-10 levels were detected by ELISA. The cell proliferation, migration, and invasion of FTC133 cells were determined with a CCK-8 assay and a Transwell assay, respectively. In addition, HUVEC vasculature formation was measured by matrigel angiogenesis assay. The higher levels of MALAT-1 and FGF2 were observed in thyroid cancer tissues and in thyroid cancer cells compared to that in the control. Besides, in the presence of si-MALAT1, the levels of TNF-α and IL-12 were significantly up-regulated whereas IL-10 was down-regulated in the CM from TAMs. Moreover, down-regulation of MALAT1 in TAMs reduced proliferation, migration, and invasion of FTC133 cells and inhibited angiogenesis. However, overexpression of FGF2 blocked the effects of MALAT1 siRNAs on cell migration, invasion, and angiogenesis. Our results suggest that MALAT1-mediated FGF2 protein secretion from TAMs inhibits inflammatory cytokines release, promotes proliferation, migration, and invasion of FTC133 cells and induces vasculature formation. J. Cell. Biochem. 118: 4821-4830, 2017. © 2017 Wiley Periodicals, Inc.

M2 macrophage is the predominant phenotype in airways inflammatory lesions in patients with granulomatosis with polyangiitis

Background

Macrophages may present two distinct phenotypes indicated as M1 and M2 under different stimuli. M1 and M2 macrophages have divergent functions that range from enhancement of inflammation for M1 to tissue repair and remodeling for M2 macrophages. The objective of this study was to evaluate the distribution of M1 and M2 macrophage phenotypes in biopsies from the airways of patients with active granulomatosis with polyangiitis (GPA) and to analyze their associations with T and B cells in those biopsies, and with nasal carriage of Staphylococcus aureus, disease parameters and therapy.

Methods

Consecutive GPA patients (n = 35) with active airway disease, who underwent respiratory tract biopsy were included. Immunohistochemical evaluation was performed to assess the distribution of macrophages and T and B cells using the markers CD68, CD3 and CD20, respectively. CD86 was used as the M1 marker and CD163 as the M2 marker while Tbet and GATA-3 were used as Th1 and Th2 markers, respectively. At the time of the biopsy patients were assessed for nasal carriage of Staphylococcus aureus and treatment.

Results

Percentages of macrophages and T cells were significantly higher than those of B cells in lesional tissue from the respiratory tract in GPA. M2 macrophages and Th2 cells were more frequent than M1 macrophages (p = 0.0007) and Th1 cells (p < 0.0001), respectively. Percentages of T cells were higher in nose biopsies than in biopsies from other sites (p = 0.021); macrophages and CD163⁺ macrophages were more predominant in biopsy sites other than the nose (p = 0.039 and p = 0.012, respectively). Carriage of Staphylococcus aureus was associated with higher T cell scores (p = 0.014). The frequency of macrophages, especially M2 macrophages, was higher in GPA patients treated with immunosuppressive agents (p = 0.010); daily prednisolone dose was positively correlated with all macrophage markers. However, in multivariate analysis no independent associations were found between disease parameters and therapy with macrophage markers or T cells.

Conclusion

In GPA, M2 is the predominant macrophage phenotype in the respiratory tract. Although some associations were observed between macrophages and T cells with therapy and nasal carriage of Staphylococcus aureus, they were not independently significant in multivariate analysis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1310-4) contains supplementary material, which is available to authorized users.

Tumor reactive stroma in cholangiocarcinoma: The fuel behind cancer aggressiveness

Cholangiocarcinoma (CCA) is a highly aggressive epithelial malignancy still carrying a dismal prognosis, owing to early lymph node metastatic dissemination and striking resistance to conventional chemotherapy. Although mechanisms underpinning CCA progression are still a conundrum, it is now increasingly recognized that the desmoplastic microenvironment developing in conjunction with biliary carcinogenesis, recently renamed tumor reactive stroma (TRS), behaves as a paramount tumor-promoting driver. Indeed, once being recruited, activated and dangerously co-opted by neoplastic cells, the cellular components of the TRS (myofibroblasts, macrophages, endothelial cells and mesenchymal stem cells) continuously rekindle malignancy by secreting a huge variety of soluble factors (cyto/chemokines, growth factors, morphogens and proteinases). Furthermore, these factors are long-term stored within an abnormally remodeled extracellular matrix (ECM), which in turn can deleteriously mold cancer cell behavior. In this review, we will highlight evidence for the active role played by reactive stromal cells (as well as by the TRS-associated ECM) in CCA progression, including an overview of the most relevant TRS-derived signals possibly fueling CCA cell aggressiveness. Hopefully, a deeper knowledge of the paracrine communications reciprocally exchanged between cancer and stromal cells will steer the development of innovative, combinatorial therapies, which can finally hinder the progression of CCA, as well as of other cancer types with abundant TRS, such as pancreatic and breast carcinomas.

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.

Role of tumor-associated macrophages in human malignancies: friend or foe?

Tumor-associated macrophages (TAMs) play a pivotal role in tumor growth in human malignancies. Published studies have analyzed the relationship between TAM infiltration and the prognosis of patients for many human tumors. Most studies reported a positive correlation between TAM density and a poor prognosis. Studies focusing on macrophage phenotypes emphasized the protumor role of M2 anti-inflammatory macrophages in many types of human tumors. However, TAMs influence tumor progression in various ways that depend on differences in tumor sites, histology, and microenvironments. In this review, we summarize the function of TAMs in various human malignancies by reviewing the data provided in studies of TAMs in human malignancies.

CD44 variant-dependent redox status regulation in liver fluke-associated cholangiocarcinoma: A target for cholangiocarcinoma treatment

Expression of CD44, especially the variant isoforms (CD44v) of this major cancer stem cell marker, contributes to reactive oxygen species (ROS) defense through stabilizing xCT (a cystine–glutamate transporter) and promoting glutathione synthesis. This enhances cancer development and increases chemotherapy resistance. We investigate the role of CD44v in the regulation of the ROS defense system in cholangiocarcinoma (CCA). Immunohistochemical staining of CD44v and p38^MAPK (a major ROS target) expression in Opisthorchis viverrini‐induced hamster CCA tissues (at 60, 90, 120, and 180 days) reveals a decreased phospho‐p38^MAPK signal, whereas the CD44v signal was increased during bile duct transformation. Patients with CCA showed CD44v overexpression and negative‐phospho‐p38^MAPK patients a significantly shorter survival rate than the low CD44v signal and positive‐phospho‐p38^MAPK patients (P = 0.030). Knockdown of CD44 showed that xCT and glutathione levels were decreased, leading to a high level of ROS. We examined xCT‐targeted CD44v cancer stem cell therapy using sulfasalazine. Glutathione decreased and ROS increased after the treatment, leading to inhibition of cell proliferation and induction of cell death. Thus, the accumulation of CD44v leads to the suppression of p38^MAPK in transforming bile duct cells. The redox status regulation of CCA cells depends on the expression of CD44v to contribute the xCT function and is a link to the poor prognosis of patients. Thus, an xCT inhibitor could inhibit cell growth and activate cell death. This suggests that an xCT‐targeting drug may improve CCA therapy by sensitization to the available drug (e.g. gemcitabine) by blocking the mechanism of the cell's ROS defensive system.

Potential scenarios leading to ovarian cancer arising from endometriosis

OBJECTIVES

The aim of this review was to highlight recent advances in our understanding of the pathogenesis of malignant transformation of endometriosis.

METHODS

This study reviewed the English-language literature concerning basic science studies of the potential promotion of carcinogenesis.

RESULTS

Repeated episodes of hemorrhage occur in endometriosis at the onset of menstruation. Extracellular hemoglobin, heme, and iron derivatives in endometriosis cause DNA damage and mutations, which create increased cellular susceptibility to oxidant-mediated cell killing. Excess DNA damage and mutations are linked to cell death, but not carcinogenesis. In response to an oxidative and inflammatory microenvironment, endometriotic cells and macrophages secrete antioxidants that control excess oxidative stress in the surrounding environment. Exposure of endometriotic cells to a sublethal level of oxidative stress may lead to carcinogenesis. Macrophages also secrete immunosuppressive factors that lead to promotion of malignant transformation.

DISCUSSION

At least two potential scenarios could result in ovarian cancer arising from endometriosis. The first step: extracellular hemoglobin, heme, and iron cause cellular oxidative damage by promoting reactive oxygen species formation, which results in DNA damage and mutations (ovarian cancer initiation from endometriosis). The second step: cancer progression may be associated with persistent antioxidant production favoring a protumoral microenvironment.

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.