The tumorigenic liver fluke Opisthorchis viverrini--multiple pathways to cancer

Improving the Detection of Cholangiocarcinoma: In vitro MRI-Based Study Using Local Coils and T2 Mapping

Aim

Cholangiocarcinoma is endemic in southeast Asia, generally developing from liver fluke infestation. However, diagnostic imaging of early-stage disease is challenging. The aim of this work is to investigate relaxometry (specifically, T2 mapping) as a method of exploiting the higher signal-to-noise ratio (SNR) of internal coils for improved reception of magnetic resonance signals, despite their non-uniform sensitivity.

Methods

Ex vivo T2 mapping was carried out at 3T on fixed resection specimens from Thai cholangiocarcinoma patients using an mGRASE sequence and an endoscope coil based on a thin-film magneto-inductive waveguide and designed ultimately for internal use.

Results

Disease-induced changes including granulomatous inflammation, intraepithelial neoplasia and intraductal tumours were correlated with histopathology, and relaxation data were compared with mono- and bi-exponential models of T2 relaxation. An approximately 10-fold local advantage in SNR compared to a 16-element torso coil was demonstrated using the endoscope coil, and improved tissue differentiation was obtained without contrast agents.

Conclusion

The performance advantage above follows directly from the inverse relation between the component of the standard deviation of T2 due to thermal noise and the SNR, and offers an effective method of exploiting the SNR advantage of internal coils. No correction is required, avoiding the need for tracking, relaxing constraints on coil and slice orientation and providing rapid visualization.

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.

Evaluation of p53 and Its Target Gene Expression as Potential Biomarkers of Cholangiocarcinoma in Thai Patients

BACKGROUND

Cholangiocarcinoma (CCA), a common cancer in northeastern Thailand, is a severe disease with poor prognosis and short survival time following diagnosis. DNA damage in CCA is believed to be caused by liver fluke infection in combination with exposure to carcinogens. p53, a tumor suppressor, is the most mutated gene in human cancers including liver fluke-associated CCA. Hence, expression patterns of p53 and its target genes may be useful for diagnosis and/or prognosis of CCA patients.

METHODS

Differential mRNA expression of p53 and its target genes, namely, FUCA1, ICAM2 MDM2, p21, PAI-1, S100A9, and WIP1 in CCA tissue samples (n = 30) relative to matched adjacent non-tumor tissues was determined by quantitative RT-PCR and compared to clinicopathological features. Level of p53 protein was determined by immunohistochemistry and correlated with the expression of its target genes.

RESULTS

Immunohistochemistry showed elevation of p53 protein level in 77% of the cases, while RT-PCR showed downregulation of p53 mRNA and its seven target genes in 23% and 47-97% of the samples. PAI-1 was down-regulated in almost all CCA samples, thus highlighting it as a potential diagnostic marker for CCA. However, no significant clinical associations were found except for down-regulation of WIP1 that was significantly correlated with non-papillary type tissue (p-value = 0.001) and with high p53 protein level (p-value = 0.007).

CONCLUSION

Our results demonstrated statistically significant association between down-regulation of WIP1 with non-papillary type and with high p53 protein level, and PAI-1 was down-regulated in almost all CCA. Therefore, expression level of WIP1 and PAI-1 may be useful for predicting p53 functional status and as a potential diagnostic marker of CCA, respectively.

Clonorchis sinensis and clonorchiasis

Clonorchis sinensis is a fish-borne trematode that inhabits the bile duct of mammals including humans. Clonorchiasis is prevalent in China, Korea, and Vietnam, and 15-20 million people are estimated to be infected by this fluke. Freshwater snails act as the first intermediate host for the proliferation of C. sinensis larvae and shed the cercariae into water. The cercariae penetrate the skin of freshwater fish and transform to metacercariae. Humans are infected by eating raw or undercooked freshwater fish as dishes of filet, "sashimi," or congee, which contain C. sinensis metacercariae. In humans, the C. sinensis metacercariae excyst in the duodenum, and juvenile flukes migrate up via bile chemotaxis into bile ducts. Once there, C. sinensis provokes hyperplasia of the bile duct epithelium, obstructive jaundice, ascites, liver enlargement and cirrhosis, and infrequent cholangiocarcinoma (CCA). Although the association between C. sinensis infection and CCA has been firmly established in past decades, the underlying mechanisms are not elucidated in detail. In the context of chronic clonorchiasis-associated hepatobiliary aberrations, the constitutive disruption of redox homeostasis and dysregulation of physiological signaling pathways may promote the malignant transformation of cholangiocytes, thus leading to substantial acquisition of a more aggressive phenotype by these cells: CCA. With advances of genomic and molecular biological approaches, diverse C. sinensis proteins that are essential for parasite physiology and pathogenicity have been identified and characterized. Some of the proteins have been considered as attractive targets for development of vaccines and chemotherapeutics. Candidate antigens for reliable serodiagnosis of clonorchiasis have been studied.

Liver cancer incidence and mortality: Disparities based on age, ethnicity, health and nutrition, molecular factors, and geography

Liver cancer (LCa) is the fifth and eighth leading cause of cancer death for men and women, respectively. However, despite improvements in treatment strategies and options, it has limited therapeutic options. Worldwide, the prevalence of LCa varies widely. Various factors are associated with the development of LCa, and its incidence, morbidity, and mortality rates differ due to disparities that are multifactorial and complex, including genetic and geographic factors. The frequency of LCa varies by race/ethnicity, age and sex and relates to viral infections, lifestyle, nutrition, obesity, and health. In addition, various molecular factors, including cytokines, hormones, apoptosis, and mutations, are involved in disparities in the progression and mortality of LCa. Here, we provide an overall perspective on LCa by presenting available information on these associated factors and discussing their importance in its disproportionate incidences and clinical outcomes.

Current and Novel Therapies Against Helminthic Infections: The Potential of Antioxidants Combined with Drugs

Infections caused by Schistosoma haematobium and Opisthorchisviverrini are classified as Group 1 biological carcinogen and it has been postulated that parasites produce oxysterol and estrogen-like metabolites that might be considered as initiators of infection-associated carcinogenesis. Chemotherapy for these helminthic infections relies on a single drug, praziquantel, (PZQ) that mainly targets the parasite. Additionally, PZQ has some major drawbacks as inefficacy against juvenile form and alone it is not capable to counteract pathologies associated to infections or prevent carcinogenesis. There is an urgent need to develop novel therapeutic approaches that not only target the parasite but also improve the pathologies associated to infection, and ultimately, counteract or/and prevent the carcinogenesis processes. Repurposing the drug in combination of compounds with different modes of action is a promising strategy to find novel therapeutics approaches against these helminthic infections and its pathologies. Here, we emphasized that using antioxidants either alone or combined with anthelmintic drugs could ameliorate tissue damage, infection-associated complications, moreover, could prevent the development of cancer associated to infections. Hence, antioxidants represent a potential adjuvant approach during treatment to reduce morbidity and mortality. Despite the success of some strategies, there is a long way to go to implement novel therapies for schistosomiasis.

Enhanced neutrophil functions during Opisthorchis viverrini infections and correlation with advanced periductal fibrosis

Millions of people are infected with the liver fluke, Opisthorchis viverrini (OV), but only ~25% of those infected develop liver disease and even fewer develop cholangiocarcinoma. The reasons for these differential outcomes following infection are unknown but it has been proposed that differential immune responses to the parasite may play a role. We therefore measured granulocyte (neutrophil) function in OV-infected individuals, with and without advanced periductal fibrosis, to determine if these cells have a "pro-inflammatory" phenotype that may contribute to liver disease post-infection. A case-controlled study (n = 54 in each cohort) from endemic OV-infected areas of northeastern Thailand measured neutrophil functions in whole blood from non-infected (healthy controls) and OV-infected individuals with and without APF. We measured reactive oxygen species production, phagocytosis, receptor expression and apoptosis. Secreted products from OV cultures (obtained after in vitro culture of parasites) stimulated reactive oxygen species production in non-infected healthy controls, but levels were two-fold greater after OV infection (P < 0.0001); neutrophil reactive oxygen species production in individuals with APF was double that observed in those without APF (P < 0.0001). OV-infected neutrophils had elevated CD11b expression and greater phagocytic capacity, which was even three-fold higher in those with advanced periductal fibrosis (P < 0.0001). This "activated" phenotype of circulating neutrophils was further confirmed by the observation that isolated neutrophils had delayed apoptosis ex vivo. We believe this is the first study to show that circulating blood neutrophil function is enhanced following OV infection and is more activated in those with advanced periductal fibrosis. We propose that this activated phenotype could contribute to the pathology of liver disease. These data support the hypothesis of an activated innate inflammatory phenotype following OV infection and provide the first evidence for involvement of neutrophils in disease pathology.

Microbes as Master Immunomodulators: Immunopathology, Cancer and Personalized Immunotherapies

The intricate interplay between the immune system and microbes is an essential part of the physiological homeostasis in health and disease. Immunological recognition of commensal microbes, such as bacterial species resident in the gut or lung as well as dormant viral species, i.e., cytomegalovirus (CMV) or Epstein-Barr virus (EBV), in combination with a balanced immune regulation, is central to achieve immune-protection. Emerging evidence suggests that immune responses primed to guard against commensal microbes may cause unexpected pathological outcomes, e.g., chronic inflammation and/or malignant transformation. Furthermore, translocation of immune cells from one anatomical compartment to another, i.e., the gut-lung axis via the lymphatics or blood has been identified as an important factor in perpetrating systemic inflammation, tissue destruction, as well as modulating host-protective immune responses. We present in this review immune response patterns to pathogenic as well as non-pathogenic microbes and how these immune-recognition profiles affect local immune responses or malignant transformation. We discuss personalized immunological therapies which, directly or indirectly, target host biological pathways modulated by antimicrobial immune responses.

Behavior-related risk factors for opisthorchiasis-associated cholangiocarcinoma among rural people living along the mekong river in five greater mekong subregion countries

Opisthorchiasis-associated cholangiocarcinoma (OV-CCA) is a major public health problem in Greater Mekong Subregion (GMS) Countries, the poorest region in Asia. People in this region have similar traditions or respect the same religion. There is no difference in lifestyle and food culture. Excluding Thailand, publications on risk factors for OV-CCA from the GMS Countries are few, especially data on behavioral risk factors for OV-CCA. Therefore, this study aimed to assess the behavior-related risk factors and to compare the risk of OV-CCA among rural people living along the Mekong River in five GMS countries. It was a cross-sectional analytic study during June and October 2017. All participants with informed consent completed the questionnaires. Descriptive statistics were used to describe the prevalence of risk factors. Odds ratio with 95% confidence intervals were used to compare the risk of OV-CCA. It was found that there were more drinkers than non-drinkers in all areas, except in Vietnam. The highest history of liver fluke infection was found in Cambodia. Praziquantel use and consumption of raw freshwater fish dishes were mostly found in Lao PDR. The highest consumption of nitrosamine-contaminated foodstuffs was found in Ubon Ratchathani, Thailand. The spatial comparison of OV-CCA risk showed that Lao PDR and Ubon Ratchathani were two risk areas when compared to Tachileik, Myanmar (a reference area). This study provided the behavior-related risk factors for OV-CCA among people in five GMS Countries which would be a major jigsaw puzzle leading to proactive surveillance for OV-CCA prevention in the future.

Recent advances on the immunobiology of Bithynia spp. hosts of Opisthorchis viverrini

This article reviews the past and present scientific reports regarding Bithynia spp. focusing on the biology, ecology and life cycle of Bithynia snails and their responses to Opisthorchis viverrini infection. Moreover, new data regarding comparative molecular genomics and proteomic approaches have recently revealed novel molecular components involved in the immune defence responses from Bithynia spp., providing additional perspectives for future studies. Studies on the specific interaction between Bithynia snails and their trematodes will contribute to further understanding the snail-parasite relationship with regards to epidemiology and control of Opisthorchiasis and broaden the scope on comparative immunology of gastropod snails.

Neglected Agent Eminent Disease: Linking Human Helminthic Infection, Inflammation, and Malignancy

Helminthic parasitic infection is grossly prevalent across the globe and is considered a significant factor in human cancer occurrence induced by biological agents. Although only three helminths (Schistosoma haematobium, Clonorchis sinensis, and Opisthorchis viverrini) so far have been directly associated with carcinogenesis; there are evidence suggesting the involvement of other species too. Broadly, human helminthiasis can cause chronic inflammation, genetic instability, and host immune modulation by affecting inter- and intracellular communications, disruption of proliferation-anti-proliferation pathways, and stimulation of malignant stem cell progeny. These changes ultimately lead to tumor development through the secretion of soluble factors that interact with host cells. However, the detailed mechanisms by which helminths introduce and promote malignant transformation of host cells are still not clear. Here, we reviewed the current understanding of immune-pathogenesis of helminth parasites, which have been associated with carcinogenesis, and how these infections initiate carcinogenesis in the host.

Recombinant Opisthorchis viverrini tetraspanin expressed in Pichia pastoris as a potential vaccine candidate for opisthorchiasis

Opisthorchiasis affects millions of people in Southeast Asia and has been strongly associated with bile duct cancer. Current strategic control approaches such as chemotherapy and health education are not sustainable, and a prophylactic vaccine would be a major advance in the prevention of the disease. Tetraspanins are transmembrane proteins previously described as potential vaccine candidates for other helminth infections and are also found in the membranes of the tegument and extracellular vesicles of O. viverrini. Here, we investigated the potential of a recombinant protein encoding for the large extracellular loop of O. viverrini tetraspanin-2 (rOv-LEL-TSP-2) in a hamster vaccination model. Hamsters were vaccinated with 50 and 100 μg of rOv-LEL-TSP-2 produced from Pichia pastoris yeast combined with alum CpG adjuvant via the intraperitoneal route. The number of worms recovered from hamsters vaccinated with rOv-LEL-TSP-2 was significantly reduced compared to adjuvant control groups. Fecal egg output was also significantly reduced in vaccinated animals, and the average length of worms recovered from vaccinated animals was significantly shorter than that of the control group. Vaccinated animals showed significantly increased levels of anti-rOv-TSP-2 IgG in the sera after three immunizations, as well as increased levels of several T helper type 1 cytokines in the spleen including IFN-γ and IL-6 but not the Th2/regulatory cytokines IL-4 or IL-10. These results suggest that rOv-TSP-2 could be a potential vaccine against opisthorchiasis and warrants further exploration.

Inhibition of the Formation In Vitro of Putatively Carcinogenic Metabolites Derived from S. haematobium and O. viverrini by Combination of Drugs with Antioxidants

Infections caused by Schistosoma haematobium and Opisthorchis viverrini are classified as carcinogenic. Although carcinogenesis might be a multifactorial process, it has been postulated that these helminth produce/excrete oxysterols and estrogen-like metabolites that might act as initiators of their infection-associated carcinogenesis. Current treatment and control of these infections rely on a single drug, praziquantel, that mainly targets the parasites and not the pathologies related to the infection including cancer. Thus, there is a need to search for novel therapeutic alternatives that might include combinations of drugs and drug repurposing. Based on these concepts, we propose a novel therapeutic strategy that combines drugs with molecule antioxidants. We evaluate the efficacy of a novel therapeutic strategy to prevent the formation of putative carcinogenic metabolites precursors and DNA adducts. Firstly, we used a methodology previously established to synthesize metabolites precursors and DNA adducts in the presence of CYP450. Then, we evaluated the inhibition of their formation induced by drugs and antioxidants alone or in combination. Drugs and resveratrol alone did not show a significant inhibitory effect while N-acetylcysteine inhibited the formation of most metabolite precursors and DNA adducts. Moreover, the combinations of classical drugs with antioxidants were more effective rather than compounds alone. This strategy might be a valuable tool to prevent the initiation of helminth infection-associated carcinogenesis.

Inhibition of growth and migration of cholangiocarcinoma cells by pamidronate

Pamidronate has been hypothesized to effectively inhibit cancer cell growth and metastasis in bone tissue. Furthermore, pamidronate (Pami) exerts various direct effects against several cancer cell types, including growth and migration. The present study aimed to determine the underlying mechanism of Pami's effect on the proliferation and migration of cholangiocarcinoma (CCA) cells. KKU-100 cells were used to determine the effects of Pami on cell death and migration. The following were assessed: Sulforhodamine B, colony formation, apoptosis via flow cytometry, reactive oxygen species (ROS) production and caspase-3 activity. In addition, the effects of the test compound on the mevalonate (MVA) signaling pathway were determined via western blotting and reverse transcription-quantitative PCR. Cell migration was observed via wound healing, Matrigel and gelatin zymography. The results indicated that Pami induced CCA cell death and inhibited colony formation in a dose-dependent manner, with IC₅₀ values of 444.67±44.05 µM at 24 h and 147.33±17.01 µM at 48 h. Furthermore, Pami treatment suppressed colony formation at a lower concentration than growth inhibition with IC₅₀ values of 5.36±0.31 µM. The mechanism of growth inhibition was determined to potentially be associated with increased ROS generation and stimulated caspase-3 enzyme activity, leading to the induction of apoptosis. Furthermore, Pami treatment interfered with the MVA signaling pathway by reducing Rac1 protein levels and modulating the gene and protein expression of RhoA. Furthermore, Pami suppressed CCA cell migration by decreasing matrix metalloproteinase (MMP)2 and MMP9 levels. Additionally, Pami treatment activated CCA cell death and inhibited CCA migration at low concentrations. Pami significantly decreased the protein expression levels of Rac1 in the MVA signaling pathway and may therefore be beneficial for developing a novel chemotherapeutic method for CCA.

Inhibition of Opisthorchis felineus glutathione-dependent prostaglandin synthase by resveratrol correlates with attenuation of cholangiocyte neoplasia in a hamster model of opisthorchiasis

Food-borne trematodiases represent major neglected parasitic diseases. Trematodes of the family Opisthorchiidae including Opisthorchis felineus, Opisthorchis viverrini and Clonorchis sinensis are ranked eight on the global list of the 24 most prevalent food-borne parasites. Chronic O. felineus infection symptoms include precancerous lesions with the potential for malignancy. In recent decades, liver flukes of the family Opisthorchiidae have been extensively scientifically explored, however despite this the molecular mechanisms of O. felineus pathogenicity and its carcinogenic potential have not been studied. Opisthorchis felineus glutathione-dependent prostaglandin synthase (GST σ) is the major component of the excretory-secretory product of this liver fluke. We hypothesised that the activity of this enzyme is involved in the infection pathogenesis, including the formation of precancerous lesions. To test this hypothesis and to gain insights into the mechanisms of precancerous lesion formation, we (i) investigated whether excretory parasitic GST σ retains its enzymatic activity, (ii) tested resveratrol (RSV) as a possible inhibitor of this enzyme, and (iii) assessed biliary neoplasia and oxidative DNA damage as well as the expression of neoplasia and fibrogenesis marker genes after prolonged administration of RSV in a hamster model. RSV was found to inhibit GST σ enzymatic activity in a dose-dependent manner (R = 0.85, P < 0.001; half-maximal effective dose (ED₅₀) = 48.6 μM). Prolonged administration of RSV significantly suppressed high-grade biliary neoplasia (P = 0.008), attenuated upregulation of hyperplasia and fibrogenesis-related genes (Tgfb, α-SMA and CK7), and decreased the elevated oxidative DNA damage. Taking into account that RSV can influence a wide range of pathways, further research is needed to confirm the role of GST σ in O. felineus pathogenicity. Nevertheless, the chemopreventive effect of RSV targeting biliary neoplasia formation might be useful for improving the outcomes in infected populations and represents a compelling rationale for RSV testing in combination chemotherapy of opisthorchiasis.

DNA methylation and hydroxymethylation profiles reveal possible role of highly methylated TLR signaling on Fasciola gigantica excretory/secretory products (FgESPs) modulation of buffalo dendritic cells

BACKGROUND

Excretory/secretory products (ESPs) released by parasites influence the development and functions of host dendritic cells (DCs). However, little is known about changes of DNA (hydroxy)methylation on DC development during Fasciola gigantica infection. The present study aimed to investigate whether F. gigantica ESPs (FgESPs) affects the development and functions of buffalo DCs through altering the DNA (hydroxy)methylation of DCs.

METHODS

Buffalo DCs were prepared from peripheral blood mononuclear cells (PBMCs) and characterized using scanning and transmission electron microscopy (SEM/TEM) and quantitative reverse transcriptional PCR (qRT-RCR). DCs were treated with 200 μg/ml of FgESPs in vitro, following DNA extraction. The DNA methylome and hydroxymethylome were profiled based on (hydroxy)methylated DNA immunoprecipitation sequencing [(h)MeDIP-Seq] and bioinformatics analyses. qRT-RCR was also performed to assess the gene transcription levels of interest.

RESULTS

FgESPs markedly suppressed DC maturation evidenced by morphological changes and downregulated gene expression of CD1a and MHC II. Totals of 5432 and 360 genes with significant changes in the 5-methylcytosine (5-mC) and the 5-hydroxymethylcytosine (5-hmC) levels, respectively, were identified in buffalo DCs in response to FgESPs challenge. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these differentially expressed genes were highly enriched in pathways associated with immune response. Some cancer-related pathways were also indicated. There were 111 genes demonstrating changes in both 5-mC and 5-hmC levels, 12 of which were interconnected and enriched in 12 pathways. The transcription of hypermethylated genes TLR2, TLR4 and IL-12B were downregulated or in a decreasing trend, while the mRNA level of high-hydroxymethylated TNF gene was upregulated in buffalo DCs post-exposure to FgESPs in vitro.

CONCLUSIONS

To our knowledge, the present study provides for the first time a unique genome-wide profile of DNA (hydroxy)methylation for DCs that interact with FgESPs, and suggests a possible mechanism of FgESPs in suppressing DC maturation and functions that are involved in TLR signaling.

Vaccination of hamsters with Opisthorchis viverrini extracellular vesicles and vesicle-derived recombinant tetraspanins induces antibodies that block vesicle uptake by cholangiocytes and reduce parasite burden after challenge infection

Background

The liver fluke Opisthorchis viverrini infects several million people in Southeast Asia. Adult flukes live in the bile ducts of humans, where they cause hepatobiliary pathology, including cholangiocarcinoma. Here, we investigated the potential of extracellular vesicles (EVs) secreted by the fluke and defined recombinant proteins derived from EVs to generate protective immunity in a hamster vaccination-challenge model.

Methodology/Principal findings

EVs isolated from the excretory-secretory products of O. viverrini and two recombinant EV surface proteins encoding the large extracellular loops (LEL) of Ov-TSP-2 (rOv-TSP-2) and Ov-TSP-3 (rOv-TSP-3) were adjuvanted and used to vaccinate hamsters intraperitoneally followed by challenge infection with O. viverrini metacercariae. The number of adult flukes recovered from hamsters immunized with EVs, rOv-TSP-2, rOv-TSP-3 and rOv-TSP-2+rOv-TSP-3 were significantly reduced compared to control animals vaccinated with adjuvant alone. The number of eggs per gram feces was also significantly reduced in hamsters vaccinated with rOv-TSP-2 compared to controls, but no significant differences were found in the other groups. The average length of worms recovered from hamsters vaccinated with EVs, rOv-TSP-2 and rOv-TSP-3 was significantly shorter than that of worms recovered from the control group. Anti-EV IgG levels in serum and bile were significantly higher in hamsters vaccinated with EVs compared to control hamsters both pre- and post-challenge. In addition, levels of anti-rOv-TSP antibodies in the serum and bile were significantly higher than control hamsters both pre- and post-challenge. Finally, antibodies against rOv-TSP-2 and rOv-TSP-3 blocked uptake of EVs by human primary cholangiocyte in vitro, providing a plausible mechanism by which these vaccines exert partial efficacy and reduce the intensity of O. viverrini infection.

Conclusion/Significance

Liver fluke EVs and recombinant tetraspanins derived from the EV surface when administered to hamsters induce antibody responses that block EV uptake by target bile duct cells and exert partial efficacy and against O. viverrini challenge.

Cholangiocarcinoma (CCA) is a significant public health problem in countries throughout Southeast Asia. In these areas CCA has a strong association with chronic infection with the food-borne liver fluke Opisthorchis viverrini. Current control of the infection relies on chemotherapy and health education, however these approaches are not sustainable in isolation. Hence, there is an urgent need for a vaccine against this neglected tropical disease. A vaccine against O. viverrini would confer anti-cancer protection in similar fashion to the acclaimed vaccine for human papillomavirus and cervical cancer. Toward this goal, secreted extracellular vesicles (EVs) of O. viverrini and recombinant proteins from the surface of EVs were generated and tested as vaccines in a hamster challenge model. Vaccination of hamsters with EVs and recombinant proteins induced production of antibodies in serum and bile, and those antibodies blocked uptake of EVs by primary bile duct cells in vitro. Challenge of vaccinated hamsters with infective stage flukes markedly reduced adult fluke recovery compared to the adjuvant control group. This is the first report of successful vaccination of hamsters with O. viverrini EVs and recombinant vesicle surface proteins, and provides proof-of-concept for development of subunit vaccines for this carcinogenic infection.

Clonorchis sinensis excretory-secretory products increase malignant characteristics of cholangiocarcinoma cells in three-dimensional co-culture with biliary ductal plates

Clonorchis sinensis is a carcinogenic human liver fluke, prolonged infection which provokes chronic inflammation, epithelial hyperplasia, periductal fibrosis, and even cholangiocarcinoma (CCA). These effects are driven by direct physical damage caused by the worms, as well as chemical irritation from their excretory-secretory products (ESPs) in the bile duct and surrounding liver tissues. We investigated the C. sinensis ESP-mediated malignant features of CCA cells (HuCCT1) in a three-dimensional microfluidic culture model that mimics an in vitro tumor microenvironment. This system consisted of a type I collagen extracellular matrix, applied ESPs, GFP-labeled HuCCT1 cells and quiescent biliary ductal plates formed by normal cholangiocytes (H69 cells). HuCCT1 cells were attracted by a gradient of ESPs in a concentration-dependent manner and migrated in the direction of the ESPs. Meanwhile, single cell invasion by HuCCT1 cells increased independently of the direction of the ESP gradient. ESP treatment resulted in elevated secretion of interleukin-6 (IL-6) and transforming growth factor-beta1 (TGF-β1) by H69 cells and a cadherin switch (decrease in E-cadherin/increase in N-cadherin expression) in HuCCT1 cells, indicating an increase in epithelial-mesenchymal transition-like changes by HuCCT1 cells. Our findings suggest that C. sinensis ESPs promote the progression of CCA in a tumor microenvironment via the interaction between normal cholangiocytes and CCA cells. These observations broaden our understanding of the progression of CCA caused by liver fluke infection and suggest a new approach for the development of chemotherapeutic for this infectious cancer.

The oriental liver fluke, Clonorchis sinensis, is a biological carcinogen of humans and is the cause of death of infectious cancer patients in China and Korea. Its chronic infection promotes cholangiocarcinogenesis due to direct contact of host tissues with the worms and their excretory-secretory products (ESPs); however, the specific mechanisms underlying this pathology remain unclear. To assess its contribution to the progression of cholangiocarcinoma (CCA), we developed a 3-dimensional (3D) in vitro culture model that consists of CCA cells (HuCCT1) in direct contact with normal cholangiocytes (H69), which are subsequently exposed to C. sinensis ESPs; therefore, this model represents a C. sinensis-associated CCA microenvironment. Co-cultured HuCCT1 cells exhibited increased motility in response to C. sinensis ESPs, suggesting that this model may recapitulate some aspects of tumor microenvironment complexity. Proinflammatory cytokines such as IL-6 and TGF-β1 secreted by H69 cells exhibited a crosstalk effect regarding the epithelial-mesenchymal transition of HuCCT1 cells, thus, promoting an increase in the metastatic characteristics of CCA cells. Our findings enable an understanding of the mechanisms underlying the etiology of C. sinensis-associated CCA, and, therefore, this approach will contribute to the development of new strategies for the reduction of its high mortality rate.

Seasonal development of the coccidian parasite Goussia bayae and hepatobiliary histopathology in white perch Morone americana from Chesapeake Bay

The coccidium Goussia bayae infects the gallbladder and bile ducts of white perch Morone americana from Chesapeake Bay, USA. Seasonal changes in coccidian infections were analyzed from bile specimens of 1588 fish from the Choptank River during 2016-2018 using wet mount preparations with a Sedgwick-Rafter counting chamber. Histopathology of the gallbladder and liver was analyzed from a subset (n = 480) of these fish. Maximum parasite prevalence (100%) and intensities in the gallbladder occurred during the fish spawning season in March and April. Asynchronous coccidian development and prevalence of infections in fish increased gradually during autumn and winter, but coccidian intensity increased sharply 2-4 wk prior to the onset of fish spawning activity and decreased after spawning activity concluded. Sporulation was internal, and the gallbladder was the primary reservoir for oocysts. Two previously undescribed species of coccidia were observed in the intestine. Lesions in the gallbladder were rare and included cholecystitis and epithelial necrosis. Intrahepatic bile duct lesions were more common and included distension, cholangitis, epithelial erosion and necrosis, cholestasis, hyperplasia, and neoplasia. Cholangitis and necrosis of intrahepatic bile ducts were significantly associated with coccidial infections, while plasmodia of a myxosporean (spore morphology consistent with the genera Myxidium and Zschokella) were significantly associated with bile duct hyperplasia. Biliary neoplasia included cholangiomas (5% prevalence) and cholangiocarcinomas (1% prevalence). No association was detected between G. bayae and biliary neoplasms, but an association may exist between these lesions and the myxosporean plasmodia.

Establishment of Highly Transplantable Cholangiocarcinoma Cell Lines from a Patient-Derived Xenograft Mouse Model

Cholangiocarcinoma (CCA) is a deadly malignant tumor of the liver. It is a significant health problem in Thailand. The critical obstacles of CCA diagnosis and treatment are the high heterogeneity of disease and considerable resistance to treatment. Recent multi-omics studies revealed the promising targets for CCA treatment; however, limited models for drug discovery are available. This study aimed to develop a patient-derived xenograft (PDX) model as well as PDX-derived cell lines of CCA for future drug screening. From a total of 16 CCA frozen tissues, 75% (eight intrahepatic and four extrahepatic subtypes) were successfully grown and subpassaged in Balb/c Rag-2-/-/Jak3-/- mice. A shorter duration of PDX growth was observed during F0 to F2 transplantation; concomitantly, increased Oct-3/4 and Sox2 were evidenced in 50% and 33%, respectively, of serial PDXs. Only four cell lines were established. The cell lines exhibited either bile duct (KKK-D049 and KKK-D068) or combined hepatobiliary origin (KKK-D131 and KKK-D138). These cell lines acquired high transplantation efficiency in both subcutaneous (100%) and intrasplenic (88%) transplantation models. The subcutaneously transplanted xenograft retained the histological architecture as in the patient tissues. Our models of CCA PDX and PDX-derived cell lines would be a useful platform for CCA precision medicine.

Serum pyruvate dehydrogenase kinase as a prognostic marker for cholangiocarcinoma

Pyruvate dehydrogenase kinase (PDK) is a Ser/Thr kinase that inactivates mitochondrial pyruvate dehydrogenase and serves a key role in aerobic glycolysis, which is a hallmark of cancer cells. The present study determined the PDK expression in cholangiocarcinoma (CCA) tissues and sera to evaluate their applicability as a biomarker for CCA. Using proteomic analysis, PDK was revealed to be the most overexpressed mitochondrial protein in CCA tissues. Then, the expression of PDK isoforms in CCA tissues was examined in 15 CCA cases by immunohistochemistry. The PDK3 isoform levels in the sera were measured using a dot blot assay for 39 patients with CCA, 20 patients with benign biliary disease and 19 healthy volunteers. The results revealed a 27-fold overexpression of PDK3 in cancerous tissues when compared with adjacent non-cancerous tissues. The immunohistochemical results demonstrated that the PDK1, 2 and 3, but not the PDK4, isoforms were overexpressed in cancerous tissues. When the PDK3 levels in the sera were examined, they were significantly higher in CCA when compared with the BBD and healthy groups. The specificity and sensitivity of PDK3 as a marker for CCA were 97.5 and 33.0%, respectively, and high PDK3 levels in the sera were correlated with a short survival time for CCA. In conclusion, PDK3 can be used as a diagnostic/prognostic marker for CCA.

Is Opisthorchis viverrini Emerging in Cambodia?

Opisthorchis viverrini infection is widely prevalent in Southeast Asia. In Cambodia information on this helminth infection is scare. Recent reports suggest that O. viverrini is an emerging public health problem. We aimed to synthesize all information in relation to the infection, epidemiology, and morbidity of O. viverrini in Cambodia; from published as well as thus far unpublished sources. First reports on O. viverrini date back to 1995. In 2006 an O. viverrini initiative was launched by the national helminth control program. Since then O. viverrini has been reported in all - except two - provinces. Villages with high prevalences (>20%) were found in provinces from Preah Vihear to Takeo. The infection has a highly focal distribution. In many villages no infections were detected. O. viverrini infection was also reported in cats, dogs and intermediate hosts. No report on morbidity associated with O. viverrini was found. The current evidence suggests that O. viverrini infection remains underreported in Cambodia. It is likely that the transmission will further increase in the future with potentially serious consequences for human health.

Serum cell-free DNA methylation of OPCML and HOXD9 as a biomarker that may aid in differential diagnosis between cholangiocarcinoma and other biliary diseases

BACKGROUND

Cholangiocarcinoma (CCA) is a fatal cancer of the bile duct epithelial cell lining. The misdiagnosis of CCA and other biliary diseases may occur due to the similarity of clinical manifestations and blood tests resulting in inappropriate or delayed treatment. Thus, an accurate and less-invasive method for differentiating CCA from other biliary diseases is inevitable.

METHODS

We quantified methylation of OPCML, HOXA9, and HOXD9 in serum cell-free DNA (cfDNA) of CCA patients and other biliary diseases using methylation-sensitive high-resolution melting (MS-HRM). Their potency as differential biomarkers between CCA and other biliary diseases was also evaluated by using receiver operating characteristic (ROC) curves.

RESULTS

The significant difference of methylation levels of OPCML and HOXD9 was observed in serum cfDNA of CCA compared to other biliary diseases. Assessment of serum cfDNA methylation of OPCML and HOXD9 as differential biomarkers of CCA and other biliary diseases showed the area under curve (AUC) of 0.850 (0.759-0.941) for OPCML which sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were 80.00%, 90.00%, 88.88%, 81.81%, and 85.00%, respectively. The AUC of HOXD9 was 0.789 (0.686-0.892) with sensitivity, specificity, PPV, NPV, and accuracy of 67.50%, 90.00%, 87.09%, 73.46%, and 78.75%, respectively. The combined marker between OPCML and HOXD9 showed sensitivity, specificity, PPV, and NPV of 62.50%, 100%, 100%, and 72.72%, respectively, which may be helpful to prevent a misdiagnosis between CCA and other biliary diseases.

CONCLUSIONS

Our findings suggest the application of serum cfDNA methylation of OPCML and HOXD9 for differential diagnosis of CCA and other biliary diseases due to its less invasiveness and clinically practical method which may benefit the patients by preventing the misdiagnosis of CCA and avoiding unnecessary surgical intervention.

Case Report: Two Cases of Cholangiocarcinoma in Patients with Opisthorchis felineus Infection in Western Siberia, Russian Federation

Cholangiocarcinoma (CCA) is a cancer with high mortality owing to its aggressiveness and resistance to therapy. The liver flukes of the Opisthorchiidae family have been recognized as risk factors of CCA. Opisthorchis felineus infection occurs in Western Siberia, the biggest endemic area in the Russian Federation, and is associated with chronic inflammation of the bile ducts, which may be linked to severe hepatobiliary morbidity. We report two cases of confirmed CCA who had a chronic O. felineus infection. Both cases presented unspecific symptoms at the onset of the disease, a stage when severe pathological changes already had occurred. Both patients were living in endemic areas but did not receive any antihelminthic treatment. This report underlines the need for assessment of O. felineus infection as a causative factor of CCA. The results will provide further arguments for control of O. felineus in the Russian Federation.

Can CRISPR help in the fight against parasitic worms?

The first reports of CRISPR/Cas9 genome editing in flatworms could usher in a new era of research on these dangerous human parasites.

Trematode Genomics and Proteomics

Trematode infections are among the most neglected tropical diseases despite their worldwide distribution and extraordinary ability to parasitise many different host species and host tissues. Furthermore, these parasites are of great socioeconomic, medical, veterinary and agricultural importance. During the last 10 years, there have been increasing efforts to overcome the lack of information on different "omic" resources such as proteomics and genomics. Herein, we focus on the recent advances in genomics and proteomics from trematodes of human importance, including liver, blood, intestinal and lung flukes. We also provide information on the latest technologies applied to study the biology of trematodes as well as on the resources available for the study of the molecular aspects of this group of helminths.

Liver Flukes: Clonorchis and Opisthorchis

Clonorchis sinensis, Opisthorchis viverrini, and O. felineus are liver flukes of human and animal pathogens occurring across much of Europe and Asia. Nevertheless, they are often underestimated compared to other, better known neglected diseases in spite of the fact that many millions of people are infected and hundreds of millions are at risk. This is possibly because of the chronic nature of the infection and disease and that it takes several decades prior to a life-threatening pathology to develop. Several studies in the past decade have provided more information on the molecular biology of the liver flukes which clearly lead to better understanding of parasite biology, systematics, and population genetics. Clonorchiasis and opisthorchiasis are characterized by a chronic infection that induces hepatobiliary inflammation, especially periductal fibrosis, which can be detected by ultrasonography. These chronic inflammations eventually lead to cholangiocarcinoma (CCA), a usually fatal bile duct cancer that develops in some infected individuals. In Thailand alone, opisthorchiasis-associated CCA kills up to 20,000 people every year and is therefore of substantial public health importance. Its socioeconomic impacts on impoverished families and communities are considerable. To reduce hepatobiliary morbidity and CCA, the primary intervention measures focus on control and elimination of the liver fluke. Accurate diagnosis of liver fluke infections in both human and other mammalian, snail and fish intermediate hosts, are important for achieving these goals. While the short-term goal of liver fluke control can be achieved by praziquantel chemotherapy, a comprehensive health education package targeting school children is believed to be more beneficial for a long-term goal/solution. It is recommended that a transdisciplinary research or multisectoral control approach including one health and/or eco health intervention strategy should be applied to combat the liver flukes, and hence contribute to reduction of cholangiocarcinoma in endemic areas.

Risk factors for Opisthorchis viverrini infection in Nakhon Phanom, Thailand, where the infection is highly endemic

Background

Opisthorchiasis caused by Opisthorchis viverrini is a serious health issue in the Mekong basin region, resulting in a high prevalence of cholangiocarcinoma. Nakhon Phanom province had the highest prevalence of O. viverrini infection in Thailand at 60% of the surveyed population in 2009, despite the attempted control of opisthorchiasis for >50 years. Knowing risk factors for O. viverrini infection in Nakhon Phanom may lead to improved control and prevention of opisthorchiasis.

Objectives

To determine risk factors for O. viverrini infection in Nakhon Phanom.

Methods

We conducted a cross-sectional survey in Nakhon Phanom province from February to March 2014. The community was selected using a stratified random sampling method, and then, participants were selected by systematic random sampling. Individuals ≥15 years old were included. Knowledge of O. viverrini infection, and attitudes and practice to avoid it were assessed using a questionnaire. O. viverrini infection was determined by stool examination with a formalin–ether concentration method. Factors associated with the infection were determined using multivariate logistic regression analysis.

Results

Of the 134 participants, 75 (56%) were infected with O. viverrini. In the multivariate logistic regression analysis, 3 independent factors were associated with O. viverrini infection: age ≥ 55 years, odds ratio (OR) adjusted 6.36 (95% confidence interval (CI) 1.28–31.66); consumption of chopped raw-fish salad (koi pla), OR adjusted 28.74 (95% CI 3.59–230.24); and perceived susceptibility, OR adjusted 0.15 (95% CI 0.03–0.74).

Conclusions

Age ≥ 55 years, consuming koi pla, and perceived susceptibility were independently associated with O. viverrini infection in Nakhon Phanom.

FOXM1 modulates 5-fluorouracil sensitivity in cholangiocarcinoma through thymidylate synthase (TYMS): implications of FOXM1-TYMS axis uncoupling in 5-FU resistance

Fluorouracil (5-FU) is the first-line chemotherapeutic drug for cholangiocarcinoma (CCA), but its efficacy has been compromised by the development of resistance. Development of 5-FU resistance is associated with elevated expression of its cellular target, thymidylate synthase (TYMS). E2F1 transcription factor has previously been shown to modulate the expression of FOXM1 and TYMS. Immunohistochemical (IHC) analysis revealed a strong correlated upregulation of FOXM1 (78%) and TYMS (48%) expression at the protein levels in CCA tissues. In agreement, RT-qPCR and western blot analyses of four human CCA cell lines at the baseline level and in response to high doses of 5-FU revealed good correlations between FOXM1 and TYMS expression in the CCA cell lines tested, except for the highly 5-FU-resistant HuCCA cells. Consistently, siRNA-mediated knockdown of FOXM1 reduced the clonogenicity and TYMS expression in the relatively sensitive KKU-D131 but not in the highly resistant HuCCA cells. Interestingly, silencing of TYMS sensitized both KKU-D131 and HuCCA to 5-FU treatment, suggesting that resistance to very high levels of 5-FU is due to the inability of the genotoxic sensor FOXM1 to modulate TYMS expression. Consistently, ChIP analysis revealed that FOXM1 binds efficiently to the TYMS promoter and modulates TYMS expression at the promoter level upon 5-FU treatment in KKU-D131 but not in HuCCA cells. In addition, E2F1 expression did not correlate with either FOXM1 or TYMS expression and E2F1 depletion has no effects on the clonogenicity and TYMS expression in the CCA cells. In conclusion, our data show that FOXM1 regulates TYMS expression to modulate 5-FU resistance in CCA and that severe 5-FU resistance can be caused by the uncoupling of the regulation of TYMS by FOXM1. Our findings suggest that the FOXM1–TYMS axis can be a novel diagnostic, predictive and prognostic marker as well as a therapeutic target for CCA.

High macrophage activities are associated with advanced periductal fibrosis in chronic Opisthorchis viverrini infection

Liver fluke infection caused by Opisthorchis viverrini induces several hepatobiliary conditions including advanced periductal fibrosis (APF) and cholangiocarcinoma (CCA), but >25% of the infected population develops APF and 1% develop CCA. The innate immune response is the first line of defence, and macrophages are critical regulators of fibrosis. We hypothesized that macrophages from infected individuals have different capacities to either promote or suppress periductal fibrosis. We compared phagocytic activities of macrophages of healthy individuals and O viverrini-infected individuals ± APF, and found that macrophages from infected individuals with APF ingested significantly higher numbers of beads compared with healthy controls and O viverrini-infected individuals without APF. To further investigate proteolytic activity, we monitored real-time phagosomal proteolysis of beads conjugated to DQ-BODIPY-BSA using live cell imaging. We show that macrophages from O viverrini-infected individuals with APF also have elevated phagosomal proteolysis activity, which is consistent with their increased phagocytic activity. Additionally, stimulated ROS production by blood monocytes was higher in individuals with APF compared with healthy controls and infected individuals without APF. These results suggest that during O viverrini infection, macrophages with high phagocytic and proteolytic activities together with elevated ROS production are the phenotypes that can promote tissue damage, which results in periductal fibrosis.

Modeling liver fluke transmission in northeast Thailand: Impacts of development, hydrology, and control

Human infection with the Southeast Asian liver fluke Opisthorchis viverrini and liver fluke-associated cholangiocarcinoma cause significant disease burden in Southeast Asia. While there has been considerable work to understand liver fluke pathology and to reduce infection prevalence, there remains a limited understanding of the environmental determinants of parasite transmission dynamics to inform treatment and control programs. A particular setting where targeted control efforts have taken place is the Lawa Lake complex in northeast Thailand. Here, we describe the recent history of host infections, as well as the hydrologic characteristics of this floodplain ecosystem that influence the extent of snail habitat and fish mobility and the transport of human waste and parasite cercariae. Using mathematical modeling, we outline a framework for reconstructing environmental transmission of O. viverrini over the course of the Lawa Project control program from its inception in 2008 until 2016, using locally acquired but fragmentary longitudinal infection data for both humans and environmental hosts. The role of water flow in facilitating movement between snail, fish, human, and reservoir hosts is a particular focus with respect to its relevant scales and its impact on success of interventions. In this setting, we argue that an understanding of the key environmental drivers of disease transmission processes is central to the effectiveness of any environmental intervention.

Discovering proteins for chemoprevention and chemotherapy by curcumin in liver fluke infection-induced bile duct cancer

Modulation or prevention of protein changes during the cholangiocarcinoma (CCA) process induced by Opisthorchis viverrini (Ov) infection may become a key strategy for prevention and treatment of CCA. Monitoring of such changes could lead to discovery of protein targets for CCA treatment. Curcumin exerts anti-inflammatory and anti-CCA activities partly through its protein-modulatory ability. To support the potential use of curcumin and to discover novel target molecules for CCA treatment, we used a quantitative proteomic approach to investigate the effects of curcumin on protein changes in an Ov-induced CCA-harboring hamster model. Isobaric labelling and tandem mass spectrometry were used to compare the protein expression profiles of liver tissues from CCA hamsters with or without curcumin dietary supplementation. Among the dysregulated proteins, five were upregulated in liver tissues of CCA hamsters but markedly downregulated in the CCA hamsters supplemented with curcumin: S100A6, lumican, plastin-2, 14-3-3 zeta/delta and vimentin. Western blot and immunohistochemical analyses also showed similar expression patterns of these proteins in liver tissues of hamsters in the CCA and CCA + curcumin groups. Proteins such as clusterin and S100A10, involved in the NF-κB signaling pathway, an important signaling cascade involved in CCA genesis, were also upregulated in CCA hamsters and were then suppressed by curcumin treatment. Taken together, our results demonstrate the important changes in the proteome during the genesis of O. viverrini-induced CCA and provide an insight into the possible protein targets for prevention and treatment of this cancer.

Liver Fluke-Associated Biliary Tract Cancer

Cholangiocarcinoma (CCA) is an aggressive cancer arising from epithelial cells of the bile duct. Most patients with CCA have an unresectable tumor at the time of diagnosis. In Western countries, the risk of CCA increases in patients with primary sclerosing cholangitis, whereas liver fluke infection appears to be the major risk factor for CCA in Asian countries. A diagnosis of liver fluke infection often relies on stool samples, including microscopic examination, polymerase chain reaction-based assays, and fluke antigen detection. Tests of serum, saliva and urine samples are also potentially diagnostic. The presence of liver fluke along with exogenous carcinogens magnifies the risk of CCA in people living in endemic areas. The “liver fluke-cholangiocarcinoma” carcinogenesis pathways consist of mechanical damage to the bile duct epithelium, immunopathologic and cellular reactions to the liver fluke’s antigens and excretory/secretory products, liver fluke-induced changes in the biliary tract microbiome and the effects of repeated treatment for liver fluke. A vaccine and novel biomarkers are needed for the primary and secondary prevention of CCA in endemic areas. Importantly, climate change exerts an effect on vector-borne parasitic diseases, and awareness of liver fluke should be enhanced in potentially migrated habitat areas.

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.

Altered Gut Microbiota Composition in Subjects Infected With Clonorchis sinensis

Clonorchiasis is an infectious disease caused by helminths of Clonorchis sinensis (C. sinensis). The adult parasite mainly inhabits the bile duct and gall bladder, and results in various complications to the hepatobiliary system. The amount of bile secreted into the intestine is reduced in cases of C. sinensis infection, which may alter the pH of the gut and decrease the amount of surfactant protein D released from the gallbladder. However, the impact of parasitic infection on the human gut microbiome remains unclear. To this end, we examined the gut microbiota composition in 47 modified Kato–Katz thick smear-positive (egg-positive) volunteers and 42 healthy controls from five rural communities. Subjects were grouped into four sub-populations based on age and infection status. High-throughput 16S rRNA gene sequencing revealed significant changes in alpha diversity between EP1 and EN1. The beta diversity showed alterations between C. sinensis-infected subjects and healthy controls. In C. sinensis infected patients, we found the significant reduction of certain taxa, such as Bacteroides and anti-inflammatory Bifidobacterium (P < 0.05). Bacteroides, a predominant gut bacteria in healthy populations, was negatively correlated with the number of C. sinensis eggs per gram (EPG, r = −0.37, P adjust < 0.01 in 20–60 years old group; r = −0.64, P adjust = 0.04 in the 60+ years old group). What’s more, the reduction in the abundance of Bifidobacterium, a common probiotic, was decreased particularly in the 60 + years old group (r = −0.50, P = 0.04). The abundance of Dorea, a potentially pro-inflammatory microbe, was higher in infected subjects than in healthy individuals (P < 0.05). Variovorax was a unique bacteria that was only detected in infected subjects. These results clearly demonstrate the significant influence of C. sinensis infection on the human gut microbiota and provided new insights into the control, prevention, diagnosis, and clinical study of clonorchiasis through the human gut microbiota.

Granulin Expression in Hamsters during Opisthorchis viverrini Infection-Induced Cholangiocarcinogenesis

The secreted growth factor granulin (GRN) is upregulated during diverse epithelial cancers. GRN stimulates cell growth and development while inhibiting apoptosis. Orthologues of vertebrate granulins evolved in other animals including the liver fluke Opisthorchis viverrini. Curiously, liver fluke granulin, termed Ov-GRN-1 promotes cholangiocarcinogenesis during chronic opisthorchiasis but, by contrast, limited information is available concerning mammalian GRN during liver fluke infection-induced cholangiocarcinoma (CCA). Here we investigated the expression of mammalian granulin in the O. viverrini-associated a hamster model of opisthorchiasis and liver fluke infection-induced CCA. Male Syrian golden hamsters were assigned to one of four treatment groups, each group included 30 hamsters: 1) normal (control), 2) infected with O. viverrini (OV); 3) exposed to N-dimethylnitrosamine in drinking water (DMN); and 4) infected with O. viverrini and exposed to DMN (OVDMN). Immunohistochemistry using an anti-granulin specific probe for mammalian granulin was undertaken to monitor expression and location in hepatobiliary tissues of the hamsters. In parallel, cognate studies of transcription of mRNA and protein. Histopathological examination revealed development of proliferative lesions from the onset and eruption of CCA onwards, an outcome that was most prominent in the OVDMN hamsters. Proliferating cell nuclear antigen (PCNA) index rose continuously from initiation of infection and increased with lesion progression in OV, DMN and markedly in OVDMN hamsters. Expression of GRN in biliary was elevated in biliary epithelial cells in CCA lesions in hamsters in the DMN and OVDMN groups. Expression of GRN as assayed by western blot and RT-PCR reflected the same trend as seen with PCNA. Together the histopathogical and molecular assay based findings revealed marked expression of granulin during cholangiocarcinoma in these hamsters, and highlighted the prospect that granulin represents a potential prognostic marker for cholangiocarcinoma.

Human liver flukes

Liver fluke infections occur in people worldwide. In some low-income regions, a combination of ecological, agricultural, and culinary factors leads to a very high prevalence of infection but, in higher-income regions, infections are uncommon. Infection is associated with substantial morbidity and several liver fluke species are recognised as biological carcinogens. Here, we review the epidemiology, clinical significance, and diagnostic and treatment strategies of human infection with these pathogens.

Dysregulated microRNA expression profiles in cholangiocarcinoma cell-derived exosomes

AIM

Cholangiocarcinoma (CCA) is a malignant tumor of bile duct epithelial cells. The prognosis of CCA is poor due to lack of effective therapeutic targets and detection at an advanced stage. Exosomes are secreted nano-sized vesicles and contribute to the malignancy of several cancers via transferring their miRNAs between cells. Thus, exosomal miRNAs may serve as new therapeutic targets and potential biomarkers for CCA.

MAIN METHODS

Exosomes were isolated from three different CCA cell lines and normal human cholangiocyte cells, followed by miRNA profiling analysis. Potential role of dysregulated miRNA was investigated by knockdown experiment.

KEY FINDINGS

We found that 38 and 460 miRNAs in CCA exosomes were significantly up- and down-regulated, respectively. Of these differentially expressed miRNAs, the hsa-miR-205-5p and miR-200 family members were markedly up-regulated for 600-1500 folds, whereas the miR-199 family members and their clustered miRNA, hsa-miR-214-3p, were down-regulated for 1000-2000 folds. The expression patterns of these representative exosomal miRNAs were similar to those observed in all types of CCA cells. The target genes of the top ten most up- and down-regulated miRNAs are significantly associated with well-characterized cancer-related pathways. Consistently, knockdown of the most up-regulated miRNA, miR-205-5p, reduced KKU-M213 cell invasion and migration.

SIGNIFICANCE

We have demonstrated the distinct miRNA signatures in exosomes released from CCA cells, compared to normal human cholangiocyte cells. These exosomal miRNAs may have the potential to be novel therapeutic targets and biomarkers for CCA.

Opisthorchiasis and the Microbiome

The liver flukes Opisthorchis viverrini, O. felineus, and Clonorchis sinensis are closely related fish-borne trematodes endemic in East Asia, Eurasia, and Siberia. Following ingestion, the parasites locate to the biliary tree, where chronic infection frequently leads to cholangiocarcinoma (CCA). Infection with C. sinensis or O. viverrini is classified as a Group 1 carcinogen by the International Agency for Research on Cancer. Infection with O. felineus may also be carcinogenic. The mechanism(s) by which infection with these liver flukes culminates in CCA remain elusive, although they are likely to be multi-factorial. Not yet well studied is the influence of opisthorchiasis on the microbiome of the host despite reports that helminth parasites are capable of affecting the microbiome, potentially modulating gastrointestinal inflammation in response to the appearance of pathogenic strains of bacteria. Here, we review recent findings related to opisthorchiasis and the microbiome and related issues. In the hamster, a tractable model of infection with liver fluke and of infection-induced biliary morbidity and CCA, infection with O. viverrini perturbs the microbiome of the gastrointestinal tract, including increasing numbers of Lachnospiraceae, Ruminococcaceae, Lactobacillaceae, and others, while decreasing Porphyromonadaceae, Erysipelotrichaceae, and Eubacteriaceae. In addition, a complex microbial community associates with the parasites within the biliary tree, including Helicobacter pylori and related bacteria. Moreover, higher rates of infection with Helicobacter occur in Thailand in persons with opisthorchiasis in a liver fluke infection intensity-dependent manner. Experimental infection of hamsters with Opisthorchis felineus results in increased alpha diversity of the microbiota diversity in the biliary tract. In humans, infection with O. felineus modifies the composition of the biliary microbiome, with increasing numbers of species of Klebsiella, Aggregatibacter, Lactobacillus, Treponema, and others. Several phylotypes of Archaea occurred solely in bile from persons infected with O. felineus.

The Curious Case of Cholangiocarcinoma: Opportunities for Environmental Health Scientists to Learn about a Complex Disease

Deaths from complex, noncommunicable diseases such as cancer are predicted to continue to increase worldwide, with low- and middle-income countries bearing the brunt of the burden. This problem requires a concentrated global effort to avoid devastating losses of life as well as economic losses. Cholangiocarcinoma (CCA) is a readily studied model of complex, noncommunicable disease, but it receives little attention outside of the scientific community in Southeast Asia. Here, we bring attention to the opportunity to study CCA as a model to understand the role of multiple, complex factors in cancer. These factors include allostatic load, individual genetic susceptibility, and environmental exposures such as chemicals, diet, socioeconomic factors, and psychosocial stress. The study of CCA offers a unique opportunity to make novel observations that could advance progress in prevention and intervention approaches for prevalent diseases that involve complex, multifactorial interactions.

Mothers' Opisthorchis viverrini infection status and raw fish dish consumption in Lao People's Democratic Republic: determinants of child infection status

Background

Opisthorchis viverrini (Ov) infection is one of the foodborne trematodiases, which is highly endemic in Lao People’s Democratic Republic (PDR). The infection occurs especially when people eat raw fish containing Ov metacercariae. As eating raw fish is a traditional culture in Lao PDR, changing this behavior is difficult. A new approach is necessary to control Ov infection because people easily get re-infected even after taking praziquantel unless they change their behaviors. This study aimed to explore factors associated with Ov infection among children and to identify the existing behaviors and perception that might contribute to the control of Ov infection in Lao PDR. We conducted a cross-sectional study in Yommalath district, Khammouane province, in Lao PDR in August and September 2015. In this cross-sectional study, we used a semi-structured questionnaire and interviewed 348 mothers who had a child aged 5–15 years. We also collected the fecal samples from each mother-child pair and used the Kato-Katz method (three slides/sample) to detect Ov eggs.

Results

Of 284 children, 82.8% were infected with Ov. The children were more likely to be infected with Ov when their mothers were infected with Ov (adjusted odds ratio [AOR] 10.45, 95% confidence interval [CI] 3.13–34.86) or when their mothers liked raw fish dishes (AOR 2.47, 95% CI 1.07–5.69). Even though most mothers are primarily in charge of cooking family meals, fathers were also involved in the preparation of raw fish dishes.

Conclusion

This study suggests that a new approach to control Ov infection should target families or communities, rather than children only. Cooking or food preparation behaviors should be investigated in more depth.

Cholangiocarcinoma: Treatment, Outcomes, and Nutrition Overview for Oncology Nurses

BACKGROUND

Cholangiocarcinoma is a cancer that arises from the bile ducts inside or outside of the liver. Although it is a rare cancer, cholangiocarcinoma appears to be rising in incidence in the United States and worldwide.

OBJECTIVES

The diagnosis of cholangiocarcinoma frequently presents with biliary emergencies from diagnosis through treatment. The lethality of this cancer stems, in part, from challenges with supportive care during treatment. This article provides an overview of intrahepatic and extrahepatic cholangiocarcinoma, including identification of risk factors, differences in treatment approaches, palliation of symptoms, and insight into commonly asked questions.

METHODS

A comprehensive review of the current literature regarding incidence, prevalence, and treatment of cholangiocarcinoma was conducted.

FINDINGS

Nursing literature regarding cholangiocarcinoma is scarce. Studies that focus on nursing care, symptom management, and nursing management of patients with biliary obstruction are needed. Nutrition and palliative care management of patients with cholangiocarcinoma are key areas of nursing management.

Detection of Risk Groups for Carcinogenic Liver Fluke Infection by Verbal Screening Questionnaire Using a Mobile Application

The carcinogenic liver fluke, Opisthorchis viverrini, is a serious health problem in Southeast Asia where infection is associated with cholangiocarcinoma, a major cause of death in Thailand. This cross-sectional study aimed to screen for O. viverrini infection among a Thai rural population of 560 individuals from Nakhon Ratchasima, Khonkaen, and Chaiyaphum provinces with a verbal screening test with a mobile application (OvApp). Faecal samples were also processed with a mini-parasep sf parasite faecal concentrator. The infection rate of O. viverrini was found to be 2.86%. The majority of infections were detected in males aged 41–50, with primary school being their highest education level, and who were engaged in agricultural occupations. In screening for O. viverrini infection, the OvApp had a high sensitivity (87.5%), specificity (94.6%), negative predictive value (98.9%), and accuracy (98.6%). The positive predictive value was 70.0% for the OvApp. The observed agreement was substantial for this application (k-value = 0.64) indicated that it is a potentially useful tool for decreasing the cost of large-scale O. viverrini screening.

Ultrasound surveillance for cholangiocarcinoma in an endemic area: A prove of survival benefits

BACKGROUND AND AIM

Cholangiocarcinoma (CCA) is an aggressive malignancy with rapid progression and poor prognosis. Abdominal ultrasound surveillance may detect early-stage malignancy and improve surgical outcome. However, little data exist on the benefits of abdominal ultrasound surveillance in populations at high risk for CCA development in an endemic area. This study compared survival outcomes of CCA patients recruited through abdominal ultrasound surveillance program and those presented to the hospital independent of surveillance.

METHODS

The surveillance population-based cohort was 4225 villagers in Northern Thailand, aged 30-60 years, who consented to a 5-year abdominal ultrasound surveillance program, which included interval ultrasound examinations every 6 months. The non-surveillance cohort was hospital-based CCA patients diagnosed during April 2007 to November 2015. Numbers of operable tumors, percentages of R0 resection, and survival analyses were compared between the two cohorts.

RESULTS

There were 48 and 192 CCA patients in the surveillance and the non-surveillance cohorts, respectively. Of these, 37/48 (77.1%) and 22/192 (11.5%) were in an operable stage and R0 resections performed in 36/48 (97.3%) and 14/192 (63.6%), respectively. The median survival in each group was 31.8 and 6.7 months, respectively (with correction of lead time bias) (P < 0.0001). By multivariate analysis, abdominal ultrasound surveillance (hazard ratio [HR] = 0.41; P = 0.012), operable stage (HR = 0.11; P < 0.001), and serum albumin ≥ 3.5 g/dL (HR = 0.42; P < 0.001) were significantly associated with decreased mortality, whereas size of CCA (HR = 1.11; P < 0.001), serum alanine aminotransferase > 40 IU/L (HR = 1.71; P = 0.017), and tumor recurrence (HR = 4.86; P = 0.017) were associated with increased mortality.

CONCLUSION

Abdominal ultrasound surveillance provided survival benefits and should be considered in areas highly endemic for CCA to reduce mortality.

Effect of β-Eudesmol on NQO1 suppression-enhanced sensitivity of cholangiocarcinoma cells to chemotherapeutic agents

Background

Cholangiocarcinoma (CCA), an epithelial malignancy of the biliary tree, is one of the aggressive cancers with poor prognosis and unsatisfactory response to chemotherapy with acquired resistance. NAD(P)H-quinone oxidoreductase 1 (NQO1), an antioxidant/detoxifying enzyme, plays important roles in chemo-resistance and proliferation in several cancer cells. The study aimed to investigate the inhibitory effect of β-eudesmol on NQO1 enhanced chemotherapeutic effects of 5-fluorouracil (5-FU) and doxorubicin (DOX) in the high NQO1-expressing human CCA cell line, NQO1-KKU-100. In addition, the molecular events associated with the inhibition of the cell proliferation, cell migration, and induction of apoptosis were investigated.

Methods

Human CCA KKU-100 cells were exposed to β-eudesmol at various concentrations. NQO1 enzyme activity and protein expression were measured by enzymatic assay and Western blot analysis, respectively. Sulforhodamine B (SRB) assay and wound healing assay were performed to detect the inhibitory effect of β-eudesmol on cell proliferation, cell migration, and sensitivity to 5-FU and DOX. Apoptotic induction was detected by flow cytometry with annexin V/PI and DAPI nuclear staining. Caspase 3/7 activation was determined by fluorescence microscopy. The mechanism of enhanced chemo-sensitivity was evaluated by Western blot analysis.

Results

β-Eudesmol significantly suppressed NQO1 enzyme activity (both in KKU-100 cells and cell lysates) and protein expression in KKU-100 cells in a concentration-dependent manner. β-Eudesmol exhibited potent cytotoxicity on KKU-100 cells with mean ± SD IC₅₀ values of 47.62 ± 9.54 and 37.46 ± 12.58 μM at 24 and 48 h, respectively. In addition, it also potentiated the cytotoxic activities and inhibitory activities of 5-FU and DOX on cell migration through induction of cell apoptosis and activation of caspase 3/7. Western blot analysis suggested that β-eudesmol enhanced chemosensitivity was associated with the suppression of NQO1 protein and activation of Bax/Bcl-2 protein expression ratio in CCA cells.

Conclusions

β-Eudesmol may serve as a potential anti-CCA candidate particularly when used in combination with conventional chemotherapeutics. The mechanisms involved may be mediated via NQO1 suppression-related apoptosis pathway.

Hepatitis C in Laos: A 7-Year Retrospective Study on 1765 Patients

Hepatitis C virus (HCV) is a global health concern, notably in Southeast Asia, and in Laos the presentation of the HCV-induced liver disease is poorly known. Our objective was thus to describe a comprehensive HCV infection pattern in order to guide national health policies. A study on a group of 1765 patients formerly diagnosed by rapid test in health centres was conducted at the Centre of Infectiology Lao Christophe Merieux in Vientiane. The demographic information of patients, their infection status (viral load: VL), liver function (aminotransferases) and treatments were analysed. Results showed that gender distribution of infected people was balanced; with median ages of 53.8 for men and 51.6 years for women (13-86 years). The majority of patients (72%) were confirmed positive (VL > 50 IU/mL) and 28% of them had high VL (> 6log₁₀). About 23% of patients had level of aminotransferases indicative of liver damage (> 40 IU/mL); but less than 20% of patients received treatment. Patients rarely received a second sampling or medical imaging. The survey also showed that cycloferon, pegylated interferon and ribavirin were the drugs prescribed preferentially by the medical staff, without following any international recommendations schemes. In conclusion, we recommend that a population screening policy and better management of patients should be urgently implemented in the country, respecting official guidelines. However, the cost of biological analysis and treatment are significant barriers that must be removed. Public health resolutions should be immediately enforced in the perspective of meeting the WHO HCV elimination deadline by 2030.