Glucagon-like peptide 1 receptor agonist: A potential game changer for cholangiocarcinoma.

Glucagon-like peptide-1 receptor (GLP-1R) agonist, a subgroup of incretin-based anti-diabetic therapies, is an emerging medication with benefits in reducing blood glucose and weight and increasing cardiovascular protection. Contrarily, concerns have been raised about GLP-1R agonists increasing the risk of particular cancers. Recently, several epidemiological studies reported contradictory findings of incretin-based therapy on the risk modification for cholangiocarcinoma (CCA). The first cohort study demonstrated that incretin-based therapy was associated with an increased risk of CCA. Later studies, however, showed a null effect of incretin-based therapy on CCA risk for dipeptidyl peptidase-4 inhibitor nor GLP-1R agonist. Mechanistically, glucagon-like peptide 1 receptor is multifunctional, including promoting cell growth. High GLP-1R expressions were associated with progressive phenotypes of CCA cells in vitro. Unexpectedly, the GLP-1R agonist showed anti-tumor effects on CCA cells in vitro and in vivo with unclear mechanisms. Our recent report also showed that GLP-1R agonists suppressed the expression of GLP-1R in CCA cells in vitro and in vivo, leading to the inhibition of CCA tumor growth. This editorial reviews recent evidence, discusses the potential effects of GLP-1R agonists in CCA patients, and proposes underlying mechanisms that would benefit from further basic and clinical investigation.

Pesticide exposure and risk of cholangiocarcinoma: A hospital-based matched case-control study.

BACKGROUND: Cholangiocarcinoma (CCA) caused by Opisthorchis viverrini is a well-known and significant public health issue in northeastern Thailand; however, a link between pesticide exposure (PE) and CCA risk has not yet been established. Therefore, our research objective was to investigate the relationship between PE and CCA risk. METHODS: A hospital-based matched case-control study was carried out. All cases (in-patients) and controls (out-patients) were volunteers at a tertiary hospital in northeast Thailand. Between 2015 and 2019, 178 incident cases of pathologically-confirmed CCA and 356 controls were selected from the check-up clinic from the Srinagarind Hospital outpatient database (two controls per case). The recruited controls were individually-matched to the CCA cases based on sex, age (±5 years) and admission date (±3 months). During face-to-face interviews, a standardised pre-tested questionnaire was used to collect data. Multivariable conditional logistic regression was used to analyse the data. RESULTS: The respective frequency of PE between the 178 CCA cases and 356 controls was 77.0% versus 87.6% for never used, 14.6% versus 5.3% for have used but stopped and 8.4% versus 7.0% for currently using. After adjusting for the highest educational attainment, smoking behaviour, alcohol use and family history of cancer, PE was not significantly associated with CCA (p-value = 0.086). Using volunteers who have never used PE as the reference group, the respective odds of developing CCA for those who have ever used but have since stopped and are currently using was 2.04 (adjusted OR = 2.04; 95% CI: 1.03-4.04) versus 0.83 (adjusted OR = 0.83; 95% CI: 0.39-1.76) times more likely to develop CCA than those who had never used PE. CONCLUSION: There is no association between PE and the risk of CCA. Notwithstanding the finding, future research should focus on enhancing PE assessment methods that consider complex chemical mixtures, chemicals of interest, historical exposure and exposure pathways. Moreover, there is need for more extensive and longer population-based cohort studies that include younger, non-occupationally exposed individuals during periods of developmental susceptibility.

A Novel Mouse Model of Intrahepatic Cholangiocarcinoma Induced by Azoxymethane.

Cholangiocarcinoma is the second most common primary cancer of the liver and has a poor prognosis. Various animal models, including carcinogen-induced and genetically engineered rodent models, have been established to clarify the mechanisms underlying cholangiocarcinoma development. In the present study, we developed a novel mouse model of malignant lesions in the biliary ducts induced by the administration of the carcinogen azoxymethane to obese C57BLKS/J-db/db mice. A histopathological analysis revealed that the biliary tract lesions in the liver appeared to be an intrahepatic cholangiocarcinoma with higher tumor incidence, shorter experimental duration, and a markedly increased incidence in obese mice. Molecular markers analyzed using a microarray and a qPCR indicated that the cancerous lesions originated from the cholangiocytes and developed in the inflamed livers. These findings indicated that this is a novel mouse model of intrahepatic cholangiocarcinoma in the context of steatohepatitis. This model can be used to provide a better understanding of the pathogenic mechanisms of cholangiocarcinoma and to develop novel therapeutic strategies for this malignancy.

Role of Nrf2 in 1,2-dichloropropane-induced cell proliferation and DNA damage in the mouse liver.

1,2-Dichloropropane (1,2-DCP) is recognized as the causative chemical of occupational cholangiocarcinoma in printing workers in Japan. However, the cellular and molecular mechanisms of 1,2-DCP-induced carcinogenesis remains elusive. The present study investigated cellular proliferation, DNA damage, apoptosis, and expression of antioxidant and proinflammatory genes in the liver of mice exposed daily to 1,2-DCP for 5 weeks, and the role of nuclear factor erythroid 2-related factor 2 (Nrf2) in these responses. Wild-type and Nrf2-knockout (Nrf2-/-) mice were administered 1,2-DCP by gastric gavage, and then the livers were collected for analysis. Immunohistochemistry for BrdU or Ki67 and TUNEL assay revealed that exposure to 1,2-DCP dose-dependently increased proliferative cholangiocytes, whereas decreased apoptotic cholangiocytes in wild-type mice but not in Nrf2-/- mice. Western blot and quantitative real-time PCR showed that exposure to 1,2-DCP increased the levels of DNA double-strand break marker γ-H2AX and mRNA expression levels of NQO1, xCT, GSTM1, and G6PD in the livers of wild-type mice in a dose-dependent manner, but no such changes were noted in Nrf2-/- mice. 1,2-DCP increased glutathione levels in the liver of both the wild-type and Nrf2-/- mice, suggesting that an Nrf2-independent mechanism contributes to 1,2-DCP-induced increase in glutathione level. In conclusion, the study demonstrated that exposure to 1,2-DCP induced proliferation but reduced apoptosis in cholangiocytes, and induced double-strand DNA breaks and upregulation of antioxidant genes in the liver in an Nrf2-dependent manner. The study suggests a role of Nrf2 in 1,2-DCP-induced cell proliferation, antiapoptotic effect, and DNA damage, which are recognized as key characteristics of carcinogens.

Preclinical studies of toxicity and anti-cholangiocarcinoma activity of the standardized capsule formulation of Atractylodes lancea (Thunb.) DC.

BACKGROUND: Cholangiocarcinoma (CCA), the adenocarcinoma of the biliary duct, is commonly reported in Asia, with the highest incidence in northeastern Thailand. Chemotherapy of CCA has been limited by the lack of effective chemotherapeutic drugs. A series of previous in vitro and in vivo studies support further research and development of Atractylodes lancea (Thunb.) DC. (AL) as a potential candidate for treating CCA as a crude ethanolic extract. In the present study, we evaluated the toxicity and anti-CCA activity of the CMC (Chemistry, Manufacturing, and Control) capsule formulation of the ethanolic rhizome extract of AL (CMC-AL) in animals. METHODS: Major steps included acute, subchronic and chronic toxicity testing in Wistar rats and anti-CCA activity in a CCA-xenografted nude mouse model. The safety of CMC-AL was determined based on the maximum tolerated dose (MTD) and no-observed-adverse-effect level (NOAEL) according to the OECD guideline. The anti-CCA activity of CMC-AL in nude mice was evaluated after transplantation of CL-6 cells to evaluate inhibitory effects on tumor size progression and metastasis and survival time prolongation. Safety assessments included hematology, biochemistry parameters and histopathological examination. Lung metastasis was investigated using VEGF ELISA kit. RESULTS: All evaluations confirmed satisfactory pharmaceutical properties of oral formulation and safety profile of the CMC-AL with no overt toxicity up to the MTD and NOAEL of 5,000 and 3,000 mg/kg body weight, respectively. CMC-AL exhibited potent anti-CCA efficacy with regard to inhibitory activity on tumor progression and lung metastasis. CONCLUSIONS: CMC-AL is safe and should be further investigated in a clinical trial as a potential therapy for CCA patients.

Adjuvant gemcitabine plus cisplatin versus capecitabine in node-positive extrahepatic cholangiocarcinoma: the STAMP randomized trial.

BACKGROUND AND AIMS: The effectiveness of gemcitabine-based adjuvant chemotherapy is unclear in cholangiocarcinoma. We investigated the role of adjuvant gemcitabine plus cisplatin (GemCis) in a homogeneous group of high-risk patients with resected, lymph node-positive extrahepatic cholangiocarcinoma. APPROACH AND RESULTS: Adenocarcinoma of perihilar or distal bile duct with regional lymph node metastasis who underwent curative-intent surgery (R0/R1) was eligible. Patients were randomized to receive GemCis (gemcitabine 1000 mg/m2, cisplatin 25 mg/m2 on days 1 and 8) or capecitabine (1250 mg/m2 twice daily on days 1-14) every 3 weeks for 8 cycles. Primary endpoint was disease-free survival. Secondary endpoints were overall survival and safety. All p values are 1 sided and were considered significant if <0.1. Between July 2017 and November 2020, 101 patients (50 in the GemCis and 51 in the capecitabine group) were included in the intention-to-treat population. Perihilar and distal bile ducts were the primary sites in 45 (44.6%) and 56 (55.4%) patients, respectively, and 32 (31.7%) had R1 resections. Median (1-sided 90% CI) follow-up duration was 33.4 (30.5-35.8) months. In the GemCis and capecitabine group, 2-year disease-free survival rates were 38.5% (29.5%-47.4%) and 25.1% (17.4%-33.5%) [HR=0.96 (CI, 0.71-1.30), p=0.430], and median overall survival was 35.7 months (29.5-not estimated) and 35.7 months (30.9-not estimated) [HR=1.08 (CI, 0.71-1.64), 1-sided p=0.404], respectively. Grade 3-4 adverse events occurred in 42 (84.0%) and 8 patients (16.0%) in the GemCis and capecitabine groups, respectively. No treatment-related deaths were reported. CONCLUSIONS: In resected lymph node-positive extrahepatic cholangiocarcinoma, adjuvant GemCis did not improve survival outcomes compared with capecitabine.

Asbestos exposure as an additional risk factor for small duct intrahepatic cholangiocarcinoma: a pilot study.

Intrahepatic cholangiocarcinoma (iCCA) is a rare malignancy, recently classified in small duct and large duct morphological subtypes. Growing evidence suggests asbestos as a putative risk factor for iCCA, albeit no correlation between asbestos and iCCA morphology has been investigated so far. The aim of the present study was to assess the relationship between asbestos exposure and iCCA morphological subtype. Forty patients with surgically removed iCCA were prospectively enrolled: asbestos exposure was assessed according to the Italian National Mesothelioma Register questionnaire. From the surgical iCCA specimens the main histopathological variables were collected, including the small duct (sd-iCCA, 32 patients) and large duct subtypes (ld-iCCA, 8 patients). Five sd-iCCA cases had a definite/probable occupational exposure to asbestos, while no cases of ld-iCCA were classified as being occupationally exposed (definite/probable). Other kind of asbestos exposure (i.e. possible occupational, familial, environmental) were recorded in 16 sd-iCCA and 3 ld-iCCA. Cases with unlikely exposure to asbestos were 11 sd-iCCA (35.5%) and 5 ld-iCCA (62.5%). In conclusion, these findings seem to indicate that sd-iCCA might be more frequently associated to asbestos exposure rather than ld-iCCA, suggesting that asbestos fibres might represent a parenchymal, rather than a ductal risk factor for iCCA. This pilot study must be confirmed by further case-control studies or large independent cohorts.

Randomized phase III study of gemcitabine, cisplatin plus S-1 versus gemcitabine, cisplatin for advanced biliary tract cancer (KHBO1401- MITSUBA).

BACKGROUND: Gemcitabine/cisplatin (GC) combination therapy has been the standard palliative chemotherapy for patients with advanced biliary tract cancer (BTC). No randomized clinical trials have been able to demonstrate the survival benefit over GC during the past decade. In our previous phase II trial, adding S-1 to GC (GCS) showed promising efficacy and we aimed to determine whether GCS could improve overall survival compared with GC for patients with advanced BTC. METHODS: We performed a mulitcenter, randomized phase III trial across 39 centers. Enrolled patients were randomly allocated (1:1) to either the GCS or GC arm. The GCS regimen comprised gemcitabine (1000 mg/m2 ) and cisplatin (25 mg/m2 ) infusion on day 1 and 80 mg/m2 of S-1 on days 1-7 every 2 weeks. The primary endpoint was overall survival (OS) and the secondary endpoints were progression-free survival (PFS), response rate (RR), and adverse events (AEs). This study is registered with Clinical trial identification: NCT02182778. RESULTS: Between July 2014 and February 2016, 246 patients were enrolled. The median OS and 1-year OS rate were 13.5 months and 59.4% in the GCS arm and 12.6 months and 53.7% in the GC arm, respectively (hazard ratio [HR] 0.79, 90% confidence interval [CI]: 0.628-0.996; P = .046 [stratified log-rank test]). Median PFS was 7.4 months in the GCS arm and 5.5 months in the GC arm (HR 0.75, 95% CI: 0.577-0.970; P = .015). RR was 41.5% in the GCS arm and 15.0% in the GC arm. Grade 3 or worse AEs did not show significant differences between the two arms. CONCLUSIONS: GCS is the first regimen which demonstrated survival benefits as well as higher RR over GC in a randomized phase III trial and could be the new first-line standard chemotherapy for advanced BTC. To exploit the advantage of its high RR, GCS is now tested in the neoadjuvant setting in a randomized phase III trial for potentially resectable BTC.

Arsenic-contaminated drinking water and cholangiocarcinoma.

INTRODUCTION: Cholangiocarcinoma (CCA) is an aggressive tumor occurring in bile ducts and associated with dismal outcomes. It can be classified according to anatomical location as intrahepatic cholangiocarcinoma (ICC) or extrahepatic cholangiocarcinoma (ECC). Although some risk factors have been identified, our understanding of these tumors remains limited. Arsenic (As) is a prevalent toxicant with established associations with bladder, skin and lung cancers while pilot data on its potential carcinogenic role on digestive tumors are emerging. This ecological study aimed to investigate the association between exposure to As-contaminated drinking water and CCA. METHODS: Analyses were conducted for the US, Taiwan and India due to the quality of publicly available datasets including small area-level information. Statistics included coefficient correlations analyses as well as univariate and multivariate linear regressions. RESULTS: In the US, no correlation was observed between As and CCA. In Taiwan, correlations were identified for ICC in men (Spearman = 0.55, P = 0.01) and women (Spearman = 0.67, P < 0.01), as well as for ECC in men (Spearman = 0.62, P < 0.01). In India, counties with As level of at least 50 µg/L showed higher incidences of ECC in men ( R2 = 0.26, P = 0.01) and women ( R2 = 0.31, P < 0.01). CONCLUSION: These findings highlighted a potential carcinogenic impact of As in drinking water on bile duct cancers, paving the way for future studies aiming to replicate this association with individual data as well as its clinical and ecological implications.

Outcomes following FGFR Inhibitor Therapy in Patients with Cholangiocarcinoma.

BACKGROUND: Sequencing efforts in patients with cholangiocarcinoma (CCA) have provided insights into molecular mechanisms including fibroblast growth factor receptor (FGFR) alterations. There is a lack of data on outcomes of patients following cessation of FGFR inhibitor (FGFRi) therapy. OBJECTIVE: We describe the clinical outcomes following initial FGFRi treatment in CCA harboring FGFR alterations. PATIENTS AND METHODS: We conducted a multicentric, retrospective analysis of patients with FGFR-altered CCA diagnosed between 2010 and 2021. Median overall survival (OS) and progression-free survival (PFS) analyses were performed using the Kaplan-Meier method. RESULTS: We identified 88 advanced or metastatic CCA patients, 28 males (31.8%) and 60 females (68.2%), harboring FGFR alterations who received FGFRi. Median PFS on initial FGFRi was 6.6 months (95% confidence interval (CI): 5.5-8.3). Following cessation of first FGFRi therapy, 55% patients received systemic therapy as next line: 67% received chemotherapy or targeted treatment and 33% received another FGFRi. Median PFS for patients who received chemotherapy or targeted agent was 2.1 months (95% CI 1.6-5.7) and for patients who received a second FGFRi was 3.7 months (95% CI 1.5-not evaluable). OS was 2.0 months for patients who did not receive any therapy compared to 8.7 months with chemotherapy and 8.6 months with another FGFRi. In addition, one patient treated with pemigatinib developed FGFR2 M540_I541insMM alteration at time of resistance, which has not been functionally characterized and its effect on protein function remains unknown. CONCLUSIONS: Understanding the mechanisms of resistance with FGFRi is essential to understand sequencing of treatments. In this study, patients received standard chemotherapy in the first line and were fit enough to be considered for subsequent therapy with an FGFRi. Almost half of the patients become ineligible to receive further systemic therapy following progression on FGFRi. As more agents are being introduced, detailed understanding of outcomes following treatment with an FGFRi, including subsequent FGFRi, is essential.

Apoptotic and Anti-metastatic Effects of Atractylodes lancea (Thunb.) DC. in a Hamster Model of Cholangiocarcinoma.

OBJECTIVES: Cholangiocarcinoma (CCA) is a highly aggressive tumor with a greater risk of distant metastasis. The promising anti-CCA activity and safety profile of Atractylodes lancea (AL) have previously been reported in a series of in vitro, in vivo and clinical studies. The present study investigated the effect of AL extract on apoptosis and metastasis signaling pathways in the Opisthorchis viverrini/dimethylnitrosamine (OV/DMN)-induced CCA hamster model. MATERIALS AND METHODS: Hamster liver tissues were obtained from the four groups (n = 5 per group), i.e., (i) 5-FU treated CCA (40 µg/mL); (ii) CCA; (iii) AL-treated CCA (5,000 mg/kg), and (iv) normal hamsters. Total RNA was isolated, and the expression levels of apoptosis-related and metastasis-related genes were determined by qRT-PCR analysis. RESULTS: The expression levels of p16, caspase-3, caspase-8, caspase-9, Apaf-1, p53 and Eef1a1 were downregulated, while that of the remaining genes were upregulated in CCA hamsters compared with normal hamsters. AL treatment increased the expression of p16, caspase-9, caspase-3, Apaf-1, p53 and E-cadherin and decreased the expression of cyclin D1, cdk4, Bax, Akt/PKB, Bcl-2, Mfge-8, Lass4, S100A6, TGF-ß, Smad-2, Smad-3, Smad-4, MMP-9, and N-cadherin. The expression of Eef1a1 was unchanged. CONCLUSION: The anti-CCA activity of AL in OV/DMN-induced CCA hamsters could be due to the induction of cell cycle arrest at the G1 phase and activation of the apoptosis pathway, resulting in cancer cell death. The activation of the apoptosis pathway mainly involved the intrinsic pathway (activation of caspase-3 and caspase-9 through p53 and Mfge-8 modulation and downregulation of anti-apoptotic genes Akt and Bcl-2). In addition, AL could also inhibit the canonical TGF-ß signaling pathway, MMP-9 and N-cadherin to suppress tumor metastasis.

Exposure to Asbestos and Increased Intrahepatic Cholangiocarcinoma Risk: Growing Evidences of a Putative Causal Link.

To date the true global incidence of intrahepatic cholangiocarcinoma (iCCA) and the underlying risk factors remain to be fully defined, in particular, the role of occupational and environmental factors. Currently, the putative role of asbestos exposure as a risk factor for iCCA is gaining increased attention in the international scientific community and agencies. In this commentary we review and integrate available epidemiological and mechanistic evidences that support a potential role of asbestos exposure in iCCA etiology.

Ivosidenib in IDH1-mutated cholangiocarcinoma: Clinical evaluation and future directions.

To date, treatment options for patients with chemorefractory cholangiocarcinoma (CCA) are limited. However, the advancements in molecular techniques have recently increased the opportunity to offer molecularly targeted therapies to patients with several cancer types and some targetable oncogenic alterations have been identified also in CCA. Among these potentially actionable molecular alterations, isocitrate dehydrogenase-1 (IDH1) mutations have been detected in approximately 10-20% of intrahepatic CCA (iCCA). IDH1 is responsible for the accumulation of oncometabolites inducing epigenetic changes that are involved in various signaling pathways. Ivosidenib is the first IDH1 inhibitor which significantly improved progression-free survival (PFS) (2.7 vs 1.4 months) and overall survival (OS) (10.3 vs 5.1 months [adjusted median OS]) compared with placebo in chemorefractory IDH1-mutated CCA. The very low incidence of grade (G) 3-4 adverse events (AEs) and treatment discontinuation due to toxicity, associated with a significantly less marked decline in health-related quality of life for patients in the ivosidenib group than in placebo group, facilitates patient adherence and clinician confidence. Here, we review the development of ivosidenib in CCA patients and evaluate the clinical impact of the results of the phase III ClarIDHy trial which was responsible for the Food and Drug Administration (FDA) approval for patients with IDH1-mutated CCA whose disease progressed after standard chemotherapy (CT). We also discuss the known primary and secondary resistance mechanisms, including concomitant and acquired mutations in other genes (e.g. IDH2 mutations), second-site mutation in IDH1, and enhanced activation of other pathways (e.g. PI3K/AKT/mTOR pathway). Finally we examine the future directions, as the opportunity to combine ivosidenib with other synergistic agents, including standard chemotherapy (CT), immune checkpoint inhibitors (ICIs), and IDH2 inhibitors.

Acetaminophen Overdose Enhances Early Cholangiocarcinoma in Opisthorchiasis Hamsters.

Opisthorchiasis which exerted by infection of Opisthorchis viverrini is strongly related to the incident of cholangiocarcinoma (CCA) in many Southeast Asian countries northeastern of Thailand. The O. viverrini infection is primarily caused by raw fish consumption, and repeated exposure to liver fluke. Meanwhile, acetaminophen is usually medicated to relieve pain in particularly people in northeast Thailand. OBJECTIVE: This study therefore aimed at investigating effects of acetaminophen on pathogenesis in hamsters for opisthorchiasis. METHODS: There were 4 groups of hamsters: i) uninfected hamster (N); ii) sole acetaminophen administration (N-Ac); iii) sole O. viverrini infection (OV); and iv) combination of O. viverrini infection and acetaminophen (OV-Ac) on pathology of hamsters for 1 month post infection. For analysis of histopathological changes through hematoxylin and eosin, Sirius red and immunohistostaining for Cytokeratin 19 (CK-19), Proliferating cell nuclear antigen (PCNA) and CA 19-9, serum's hamsters were used detected for liver function tests and tumor-related genes expression. RESULTS: After 1 month under these treatments, the OV-Ac showed significantly higher CCA risk, including inflammatory cells were aggregations around bile duct, new bile duct and fibrosis in subcapsular hepatic tissues, than other treatments. These pathological parameters were positively correlated with immunohistochemical staining derived from CK-19, PCNA and CA 19-9. In addition, OV-Ac had significantly higher liver function tests (ALT). CONCLUSION: Combined intake of liver fluke-contaminated raw fishes and acetaminophen rendered more severity of CCA than sole consumption of the contaminated raw fishes.

CagA+ Helicobacter pylori infection and N-nitrosodimethylamine administration induce cholangiocarcinoma development in hamsters.

BACKGROUND: Helicobacter pylori (HP) has been detected in the hepatobiliary tract of cholangiocarcinoma (CCA) patients in regions both endemic and non-endemic for Opisthorchis viverrini (OV) infection. However, whether H. pylori infection promotes CCA development remains unknown. We investigated CCA development in hamsters induced by a combination of infection with H. pylori and administration of N-nitrosodimethylamine (NDMA) and compared findings with those in an OV plus NDMA group. MATERIALS AND METHODS: Eighty-five hamsters were divided into four groups: (1) normal, (2) administered NDMA, (3) infected with cagA+ H. pylori and administered NDMA (HN group), and (4) infected with OV and administered NDMA (ON group). Animals were euthanized at 3 and 6 months post-infection. Histopathological changes of liver and the expression of markers associated with carcinogenesis were studied. RESULTS: At 3 months post-infection (p.i.), cholangitis and lymphoid follicles without tumor appearance were noted in the HN group, whereas extensive fibrosis was seen in members of the ON group, 10% of which had developed tumors. At 6 months p.i., 10% of hamsters administered NDMA alone had developed CCA, whereas in the HN and ON groups, 20% and 60% of hamsters, respectively, had developed CCA. Cytokeratin-19 (CK19) expression was observed in the CCA tissues of both the HN and the ON groups, confirming the bile duct origin of the CCA cells. CCA development in the HN group might be inflammation-mediated, as suggested by overexpression of HMGB1, PCNA, IL-8, and 8-OxodG in CCA tissues. CONCLUSION: cagA+ H. pylori infection and carcinogen intake can induce CCA development with slow progression.

A Mouse Model of Cholangiocarcinoma Uncovers a Role for Tensin-4 in Tumor Progression.

BACKGROUND AND AIMS: Earlier diagnosis and treatment of intrahepatic cholangiocarcinoma (iCCA) are necessary to improve therapy, yet limited information is available about initiation and evolution of iCCA precursor lesions. Therefore, there is a need to identify mechanisms driving formation of precancerous lesions and their progression toward invasive tumors using experimental models that faithfully recapitulate human tumorigenesis. APPROACH AND RESULTS: To this end, we generated a mouse model which combines cholangiocyte-specific expression of KrasG12D with 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) diet-induced inflammation to mimic iCCA development in patients with cholangitis. Histological and transcriptomic analyses of the mouse precursor lesions and iCCA were performed and compared with human analyses. The function of genes overexpressed during tumorigenesis was investigated in human cell lines. We found that mice expressing KrasG12D in cholangiocytes and fed a DDC diet developed cholangitis, ductular proliferations, intraductal papillary neoplasms of bile ducts (IPNBs), and, eventually, iCCAs. The histology of mouse and human IPNBs was similar, and mouse iCCAs displayed histological characteristics of human mucin-producing, large-duct-type iCCA. Signaling pathways activated in human iCCA were also activated in mice. The identification of transition zones between IPNB and iCCA on tissue sections, combined with RNA-sequencing analyses of the lesions supported that iCCAs derive from IPNBs. We further provide evidence that tensin-4 (TNS4), which is stimulated by KRASG12D and SRY-related HMG box transcription factor 17, promotes tumor progression. CONCLUSIONS: We developed a mouse model that faithfully recapitulates human iCCA tumorigenesis and identified a gene cascade which involves TNS4 and promotes tumor progression.

Brahma-Related Gene 1 Inhibition Prevents Liver Fibrosis and Cholangiocarcinoma by Attenuating Progenitor Expansion.

BACKGROUND AND AIMS: Intrahepatic cholangiocarcinoma (iCCA) is closely correlated with hepatic progenitor cell (HPC) expansion and liver fibrosis. Brahma-related gene 1 (Brg1), an enzymatic subunit of the switch/sucrose nonfermentable complex that is critical in stem cell maintenance and tumor promotion, is prominently up-regulated in both HPCs and iCCA; however, its role in this correlation remains undefined. APPROACH AND RESULTS: A retrospective cohort study indicated that high Brg1 expression suggests poor prognosis in patients with iCCA. In chronically injured livers induced by a 0.1% 3,5-diethoxycarbonyl-1,4-dihydrocollidine diet or bile duct ligation surgery, HPCs were dramatically activated, as indicated by their enhanced expression of Brg1 and a subset of stem cell markers; however, Brg1 ablation in HPCs strongly suppressed HPC expansion and liver fibrosis. Furthermore, in a chemically induced iCCA model, inhibition of Brg1 by a specific inhibitor or inducible gene ablation markedly improved histology and suppressed iCCA growth. Mechanistically, in addition to transcriptionally promoting both Wnt receptor genes and target genes, Brg1 was found to bind to the ß-catenin/transcription factor 4 transcription complex, suggesting a possible approach for regulation of Wnt/ß-catenin signaling. CONCLUSIONS: We have demonstrated the function of Brg1 in promoting HPC expansion, liver cirrhosis, and, ultimately, iCCA development in chronically injured livers, which is largely dependent on Wnt/ß-catenin signaling. Our data suggest that therapies targeting Brg1-expressing HPCs are promising for the treatment of liver cirrhosis and iCCA.

Proton pump inhibitors and odds of cholangiocarcinoma: A retrospective case-control study.

BACKGROUND & AIMS: Proton pump inhibitors (PPIs) have been reported to be associated with cholangitis and might possibly be carcinogenic. However, few studies have been conducted to investigate the association of PPIs with cholangiocarcinoma (CCA). Thus, a hospital-based case-control study was carried out in China to explore the association between PPIs and CCA. METHODS: In this study, 1468 CCA cases (826 intrahepatic cholangiocarcinoma (ICC) and 642 extrahepatic cholangiocarcinoma (ECC)) were included, which were observed at Beijing Friendship Hospital, from February 2002 to October 2018. We retrospectively extracted PPI use and other possible risk factors from clinical records, followed by an investigation of the relationship with CCA via calculation of odds ratios (ORs), adjusted odds ratios (AORs), and 95% confidence intervals (CIs) using logistic regression analysis. RESULTS: PPIs were used by 135 (9.2%) CCA cases and 173 (5.9%) controls. We found that PPI use was associated with a 1.61-fold elevated CCA odds (P < .001) (AOR = 1.61, 95% CI = 1.28-2.05; P < .001). After stratification by CCA subtypes, the AORs of PPIs were consistent for both CCA subtypes, with ORs of 1.36 (AOR = 1.36, 95% CI = 1.02-1.83; P = .003) and 1.95 (AOR = 1.95, 95% CI = 1.46-2.62; P < .001) for ICC and ECC respectively. Our results also showed that PPI use was slightly linked to the odds of CCA in a dose-dependent manner. CONCLUSION: PPI use was correlated with a significant 61% increased odds of CCA, particularly in the ECC. However, the retrospective design and observational nature cannot establish causation. Larger scale, multi-centre prospective studies are required for further validation.

Oxysterols of helminth parasites and pathogenesis of foodborne hepatic trematodiasis caused by Opisthorchis and Fasciola species.

The foodborne trematodiases refer to a cluster of zoonotic neglected tropical diseases caused by trematodes, with transmission involving ingestion of contaminated plants, fishes, and crustaceans. Over 40 million people are infected with foodborne trematodes and 750 million are at risk of infection. From a public health point of view, important species include Clonorchis sinensis, Opisthorchis viverrini, Opisthorchis felineus, Fasciola hepatica, and Fasciola gigantica. Infection with C. sinensis and O. viverrini is classified as a group 1 biological carcinogen and a major risk factor for cholangiocarcinoma. The carcinogenic potential of the infection with O. felineus is less clear but recent biochemical and histopathological findings revealed that opisthorchiasis felinea also fits this pattern. By contrast, evidence of carcinogenic potential of infection with F. hepatica or F. gigantica, close phylogenetics relatives of Opisthorchis, is less certain. Oxysterols have been essentially described in animal model of opisthorchiasis and associated cholangiocarcinoma. Several oxysterol-like metabolites have been detected not only on developmental stages of O. viverrini and O. felineus but also on biofluids from experimentally infected hamsters as products of the activities of the liver flukes. These sterol derivatives are metabolized to active quinones that can modify host DNA. We have postulated that helminth parasite-associated sterols might induce tumor-like phenotypes in biliary epithelia, the cells of origin of liver fluke infection-associated cholangiocarcinoma, through the formation of DNA adducts, dysregulation of apoptosis, and other homeostatic pathways. Here we review, interpret, and discuss findings of oxysterol-like metabolites detected in liver flukes and their role in carcinogenesis, aiming to enhance understanding the pathogenesis of foodborne trematodiasis caused by Opisthorchis and Fasciola species. In future, further investigations will be necessary in order to comprehend relationship between liver flukes' oxysterols and their role in infection-associated diseases in humans.

The Mutational Features of Aristolochic Acid-Induced Mouse and Human Liver Cancers.

BACKGROUND AND AIMS: Aristolochic acid (AA) exposure has been statistically associated with human liver cancers. However, direct evidence of AA exposure-induced liver cancer is absent. This study aims to establish a direct causal relationship between AA exposure and liver cancers based on a mouse model and then explores the AA-mediated genomic alterations that could be implicated in human cancers with AA-associated mutational signature. APPROACH AND RESULTS: We subjected mice, including phosphatase and tensin homolog (Pten)-deficient ones, to aristolochic acid I (AAI) alone or a combination of AAI and CCl4 . Significantly, AAI exposure induced mouse liver cancers, including hepatocellular carcinoma (HCC) and combined HCC and intrahepatic cholangiocarcinoma, in a dose-dependent manner. Moreover, AAI exposure also enhanced tumorigenesis in these CCl4 -treated or Pten-deficient mice. AAI led to DNA damage and AAI-DNA adduct that could initiate liver cancers through characteristic adenine-to-thymine transversions, as indicated by comprehensive genomic analysis, which revealed recurrent mutations in Harvey rat sarcoma virus oncogene. Interestingly, an AA-associated mutational signature was mainly implicated in human liver cancers, especially from China. Moreover, we detected the AAI-DNA adduct in 25.8% (16/62) of paratumor liver tissues from randomly selected Chinese patients with HCC. Furthermore, based on phylogenetic analysis, the characteristic mutations were found in the initiating malignant clones in the AA-implicated mouse and human liver cancers where the mutations of tumor protein p53 and Janus kinase 1 were prone to be significantly enriched in the AA-affected human tumors. CONCLUSIONS: This study provides evidence for AA-induced liver cancer with the featured mutational processes during malignant clonal evolution, laying a solid foundation for the prevention and diagnosis of AA-associated human cancers, especially liver cancers.