JCAD Promotes Progression of Nonalcoholic Steatohepatitis to Liver Cancer by Inhibiting LATS2 Kinase Activity

Dynamic changes of gut microbiota in mouse models of metabolic dysfunction-associated steatohepatitis and its transition to hepatocellular carcinoma

Dysbiosis of gut microbiota may account for pathobiology in simple fatty liver (SFL), metabolic dysfunction-associated steatohepatitis (MASH), fibrotic progression, and transformation to MASH-associated hepatocellular carcinoma (MASH-HCC). The aim of the present study is to investigate gut dysbiosis in this progression. Fecal microbial rRNA-16S sequencing, absolute quantification, histopathologic, and biochemical tests were performed in mice fed high fat/calorie diet plus high fructose and glucose in drinking water (HFCD-HF/G) or control diet (CD) for 2, 16 weeks, or 14 months. Histopathologic examination verified an early stage of SFL, MASH, fibrotic, or MASH-HCC progression with disturbance of lipid metabolism, liver injury, and impaired gut mucosal barrier as indicated by loss of occludin in ileum mucosa. Gut dysbiosis occurred as early as 2 weeks with reduced α diversity, expansion of Kineothrix, Lactococcus, Akkermansia; and shrinkage in Bifidobacterium, Lactobacillus, etc., at a genus level. Dysbiosis was found as early as MAHS initiation, and was much more profound through the MASH-fibrotic and oncogenic progression. Moreover, the expansion of specific species, such as Lactobacillus johnsonii and Kineothrix alysoides, was confirmed by an optimized method for absolute quantification. Dynamic alterations of gut microbiota were characterized in three stages of early SFL, MASH, and its HCC transformation. The findings suggest that the extent of dysbiosis was accompanied with MASH progression and its transformation to HCC, and the shrinking or emerging of specific microbial species may account at least in part for pathologic, metabolic, and immunologic alterations in fibrogenic progression and malignant transition in the liver.

Hippo-YAP/TAZ-ROS signaling axis regulates metaflammation induced by SelenoM deficiency in high-fat diet-derived obesity

INTRODUCTION

Metabolic inflammation (metaflammation) in obesity is primarily initiated by proinflammatory macrophage infiltration into adipose tissue. SelenoM contributes to the modulation of antioxidative stress and inflammation in multiple pathological processes; however, its roles in metaflammation and the proinflammatory macrophage (M1)-like state in adipose tissue have not been determined.

OBJECTIVES

We hypothesize that SelenoM could effectively regulate metaflammation via the Hippo-YAP/TAZ-ROS signaling axis in obesity derived from a high-fat diet.

METHODS

Morphological changes in adipose tissue were examined by hematoxylin-eosin (H&E) staining and fluorescence microscopy. The glucose tolerance test (GTT) and insulin tolerance test (ITT) were used to evaluate the impact of SelenoM deficiency on blood glucose levels. RNA-Seq analysis, LC-MS analysis, Mass spectrometry analysis and western blotting were performed to detect the levels of genes and proteins related to glycolipid metabolism in adipose tissue.

RESULTS

Herein, we evaluated the inflammatory features and metabolic microenvironment of mice with SelenoM-deficient adipose tissues by multi-omics analyses. The deletion of SelenoM resulted in glycolipid metabolic disturbances and insulin resistance, thereby accelerating weight gain, adiposity, and hyperglycemia. Mice lacking SelenoM in white adipocytes developed severe adipocyte hypertrophy via impaired lipolysis. SelenoM deficiency aggravated the generation of ROS by reducing equivalents (NADPH and glutathione) in adipocytes, thereby promoting inflammatory cytokine production and the M1-proinflammatory reaction, which was related to a change in nuclear factor kappa-B (NF-κB) levels in macrophages. Mechanistically, SelenoM deficiency promoted metaflammation via Hippo-YAP/TAZ-ROS-mediated transcriptional regulation by targeting large tumor suppressor 2 (LATS2). Moreover, supplementation with N-acetyl cysteine (NAC) to reduce excessive oxidative stress partially rescued adipocyte inflammatory responses and macrophage M1 activation.

CONCLUSION

Our data indicate that SelenoM ameliorates metaflammation mainly via the Hippo-YAP/TAZ-ROS signaling axis in obesity. The identification of SelenoM as a key regulator of metaflammation presents opportunities for the development of novel therapeutic interventions targeting adipose tissue dysfunction in obesity.

Unraveling the intricate relationship between lipid metabolism and oncogenic signaling pathways

Lipids, the primary constituents of the cell membrane, play essential roles in nearly all cellular functions, such as cell-cell recognition, signaling transduction, and energy provision. Lipid metabolism is necessary for the maintenance of life since it regulates the balance between the processes of synthesis and breakdown. Increasing evidence suggests that cancer cells exhibit abnormal lipid metabolism, significantly affecting their malignant characteristics, including self-renewal, differentiation, invasion, metastasis, and drug sensitivity and resistance. Prominent oncogenic signaling pathways that modulate metabolic gene expression and elevate metabolic enzyme activity include phosphoinositide 3-kinase (PI3K)/AKT, MAPK, NF-kB, Wnt, Notch, and Hippo pathway. Conversely, when metabolic processes are not regulated, they can lead to malfunctions in cellular signal transduction pathways. This, in turn, enables uncontrolled cancer cell growth by providing the necessary energy, building blocks, and redox potentials. Therefore, targeting lipid metabolism-associated oncogenic signaling pathways could be an effective therapeutic approach to decrease cancer incidence and promote survival. This review sheds light on the interactions between lipid reprogramming and signaling pathways in cancer. Exploring lipid metabolism as a target could provide a promising approach for creating anticancer treatments by identifying metabolic inhibitors. Additionally, we have also provided an overview of the drugs targeting lipid metabolism in cancer in this review.

SOAT1 regulates cholesterol metabolism to induce EMT in hepatocellular carcinoma

Cholesterol metabolism reprogramming is one of the significant characteristics of hepatocellular carcinoma (HCC). Cholesterol increases the risk of epithelial-mesenchymal transition (EMT) in cancer. Sterol O-acyltransferases 1 (SOAT1) maintains the cholesterol homeostasis. However, the exact mechanistic contribution of SOAT1 to EMT in HCC remains unclear. Here we demonstrated that SOAT1 positively related to poor prognosis of HCC, EMT markers and promoted cell migration and invasion in vitro, which was mediated by the increased cholesterol in plasmalemma and cholesterol esters accumulation. Furthermore, we reported that SOAT1 disrupted cholesterol metabolism homeostasis to accelerate tumorigenesis and development in HCC xenograft and NAFLD-HCC. Also, we detected that nootkatone, a sesquiterpene ketone, inhibited EMT by targeting SOAT1 in vitro and in vivo. Collectively, our finding indicated that SOAT1 promotes EMT and contributes to hepatocarcinogenesis by increasing cholesterol esterification, which is suppressed efficiently by nootkatone. This study demonstrated that SOAT1 is a potential biomarker and therapeutic target in NAFLD-HCC and SOAT1-targeting inhibitors are expected to be the potential new therapeutic treatment for HCC.

JCAD deficiency attenuates activation of hepatic stellate cells and cholestatic fibrosis

BACKGROUND/AIMS

Cholestatic liver diseases including primary biliary cholangitis (PBC) are associated with active hepatic fibrogenesis, which ultimately progresses to cirrhosis. Activated hepatic stellate cells (HSCs) are the main fibrogenic effectors in response to cholangiocyte damage. JCAD regulates cell proliferation and malignant transformation in nonalcoholic steatoheaptitis-associated hepatocellular carcinoma (NASH-HCC). However, its participation in cholestatic fibrosis has not been explored yet.

METHODS

Serial sections of liver tissue of PBC patients were stained with immunofluorescence. Hepatic fibrosis was induced by bile duct ligation (BDL) in wild-type (WT), global JCAD knockout mice (JCAD-KO) and HSC-specific JCAD knockout mice (HSC-JCAD-KO), and evaluated by histopathology and biochemical tests. In situ-activated HSCs isolated from BDL mice were used to determine effects of JCAD on HSC activation.

RESULTS

In consistence with staining of liver sections from PBC patients, immunofluorescent staining revealed that JCAD expression was identified in smooth muscle α-actin (α-SMA)-positive fibroblast-like cells and was significantly up-regulated in WT mice with BDL. JCAD deficiency remarkably ameliorated BDL-induced hepatic injury and fibrosis, as documented by liver hydroxyproline content, when compared to WT mice with BDL. Histopathologically, collagen deposition was dramatically reduced in both JCAD-KO and HSC-JCAD-KO mice compared to WT mice, as visualized by Trichrome staining and semi-quantitative scores. Moreover, JCAD deprivation significantly attenuated in situ HSC activation and reduced expression of fibrotic genes after BDL.

CONCLUSION

JCAD deficiency effectively suppressed hepatic fibrosis induced by BDL in mice, and the underlying mechanisms are largely through suppressed Hippo-YAP signaling activity in HSCs.

JCAD deficiency delayed liver regenerative repair through the Hippo-YAP signalling pathway

BACKGROUND AND AIMS

Liver regeneration retardation post partial hepatectomy (PH) is a common clinical problem after liver transplantation. Identification of key regulators in liver regeneration post PH may be beneficial for clinically improving the prognosis of patients after liver transplantation. This study aimed to clarify the function of junctional protein-associated with coronary artery disease (JCAD) in liver regeneration post PH and to reveal the underlying mechanisms.

METHODS

JCAD knockout (JCAD-KO), liver-specific JCAD-KO (Jcad△Hep) mice and their control group were subjected to 70% PH. RNA sequencing was conducted to unravel the related signalling pathways. Primary hepatocytes from KO mice were treated with epidermal growth factor (EGF) to evaluate DNA replication. Fluorescent ubiquitination-based cell cycle indicator (FUCCI) live-imaging system was used to visualise the phases of cell cycle.

RESULTS

Both global and liver-specific JCAD deficiency postponed liver regeneration after PH as indicated by reduced gene expression of cell cycle transition and DNA replication. Prolonged retention in G1 phase and failure to transition over the cell cycle checkpoint in JCAD-KO cell line was indicated by a FUCCI live-imaging system as well as pharmacologic blockage. JCAD replenishment by adenovirus reversed the impaired DNA synthesis in JCAD-KO primary hepatocyte in exposure to EGF, which was abrogated by a Yes-associated protein (YAP) inhibitor, verteporfin. Mechanistically, JCAD competed with large tumour suppressor 2 (LATS2) for WWC1 interaction, leading to LATS2 inhibition and thereafter YAP activation, and enhanced expression of cell cycle-associated genes.

CONCLUSION

JCAD deficiency led to delayed regeneration after PH as a result of blockage in cell cycle progression through the Hippo-YAP signalling pathway. These findings uncovered novel functions of JCAD and suggested a potential strategy for improving graft growth and function post liver transplantation.

KEY POINTS

JCAD deficiency leads to an impaired liver growth after PH due to cell division blockage. JCAD competes with LATS2 for WWC1 interaction, resulting in LATS2 inhibition, YAP activation and enhanced expression of cell cycle-associated genes. Delineation of JCADHippoYAP signalling pathway would facilitate to improve prognosis of acute liver failure and graft growth in living-donor liver transplantation.

Role of Hippo pathway dysregulation from gastrointestinal premalignant lesions to cancer

BACKGROUND

First identified in Drosophila melanogaster, the Hippo pathway is considered a major regulatory cascade controlling tissue homeostasis and organ development. Hippo signaling components include kinases whose activity regulates YAP and TAZ final effectors. In response to upstream stimuli, YAP and TAZ control transcriptional programs involved in cell proliferation, cytoskeletal reorganization and stemness.

MAIN TEXT

While fine tuning of Hippo cascade components is essential for maintaining the balance between proliferative and non-proliferative signals, pathway signaling is frequently dysregulated in gastrointestinal cancers. Also, YAP/TAZ aberrant activation has been described in conditions characterized by chronic inflammation that precede cancer development, suggesting a role of Hippo effectors in triggering carcinogenesis. In this review, we summarize the architecture of the Hippo pathway and discuss the involvement of signaling cascade unbalances in premalignant lesions of the gastrointestinal tract, providing a focus on the underlying molecular mechanisms.

CONCLUSIONS

The biology of premalignant Hippo signaling dysregulation needs further investigation in order to elucidate the evolutionary trajectories triggering cancer inititation and develop effective early therapeutic strategies targeting the Hippo/YAP pathway.

The circSNX14 functions as a tumor suppressor via the miR-562/ LATS2 pathway in hepatocellular carcinoma cells

Circular RNAs (circRNAs) play critical roles in the initiation and progression of various cancers. However, the potential functional roles of circSNX14 in hepatocellular carcinoma (HCC) remain largely unknown. CircSNX14 expression pattern was analyzed in HCC tissues and cell lines via qRT-PCR. The effects of circSNX14 on cell proliferation, invasion, angiogenesis, and Epithelial-mesenchymal transition (EMT) were investigated by overexpression experiments. The role of circSNX14 in the tumorigenesis of HCC cells was examined using in vivo xenograft mouse model. The interaction between circSNX14, miR-562, and Large Tumor Suppressor Kinase 2 (LATS2) mRNA was confirmed by Luciferase reporter assay and RNA immunoprecipitation (RIP) analysis. CircSNX14 was significantly down-regulated in HCC tissues and cell lines, and its down-regulation was correlated with a poor prognosis in HCC patients. In the following functional experiments, circSNX14 overexpression remarkably suppressed the proliferation and invasion of HCC cells, and attenuated the mesenchymall status. circSNX14 overexpression also suppressed the tumorigenesis of HCC cells in the mouse model. We further revealed the interaction of circSNX14 and miR-562, and miR-562 could suppress the expression of LATS2 by interacting with its mRNA. The negative correlation of circSNX14 and miR-562, negative correlation of miR-562 and LATS2, and positive correlation of circSNX14 and LATS2 have been confirmed by Pearson correlation in the HCC samples. Collectively, these results reveal a novel role of circSNX14/miR-562/LATS2 axis in regulating the malignant progression of HCC cancer progression, indicating the tumor suppressor role of circSNX14 and its potential as a prognostic biomarker.

A Review of Incidence and Related Risk Factors in the Development of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a primary liver malignancy, ranking as the seventh most common cancer globally and the second leading cause of deaths due to cancer. This review examines the incidence of HCC, its associated risk factors, and constantly changing global trends. Incidence has been noted to be varying worldwide, particularly due to environmental and infectious risk factors. Chronic hepatitis B (HBV) and C (HCV) virus infections, alcohol abuse, aflatoxin exposure, diabetes, obesity, and tobacco consumption are some of the leading risk factors noted. Eastern Asia and sub-Saharan Africa were noted to have the highest disease burden for HCC, with China representing a considerably large majority. On the contrary, the United States reports a lower HCC incidence overall due to improved vaccination programs against HBV; however, with a rising incidence of prominent risk factor in non-alcoholic fatty liver disease (NAFLD), the trend may very well change. Gender disparities were noted to be evident with men experiencing higher rates of HCC compared to women, which may be due to various environmental and biological factors, including alcohol intake, smoking, and androgen hormone levels. Currently, efforts to reduce the overall incidence of HCC include universal HBV vaccinations, antiviral therapies, aflatoxin prevention measures, genetic screening for hereditary hemochromatosis, and early ultrasound evaluation in patients with liver cirrhosis. Understanding these evolving trends and risk factors is essential in combating the rising HCC incidence, especially in Western countries, where risk factors, such as obesity, diabetes, and metabolic disorders, are on the rise.

Hydrogel platform facilitating astrocytic differentiation through cell mechanosensing and YAP-mediated transcription

Astrocytes are multifunctional glial cells that are essential for brain functioning. Most existing methods to induce astrocytes from stem cells are inefficient, requiring couples of weeks. Here, we designed an alginate hydrogel-based method to realize high-efficiency astrocytic differentiation from human neural stem cells. Comparing to the conventional tissue culture materials, the hydrogel drastically promoted astrocytic differentiation within three days. We investigated the regulatory mechanism underlying the enhanced differentiation, and found that the stretch-activated ion channels and Yes-associated protein (YAP), a mechanosensitive transcription coactivator, were both indispensable. In particular, the Piezo1 Ca2+ channel, but not transient receptor potential vanilloid 4 (TRPV4) channel, was necessary for promoting the astrocytic differentiation. The stretch-activated channels regulated the nuclear localization of YAP, and inhibition of the channels down-regulated the expression of YAP as well as its target genes. When blocking the YAP/TEAD-mediated transcription, astrocytic differentiation on the hydrogel significantly declined. Interestingly, cells on the hydrogel showed a remarkable filamentous actin assembly together with YAP nuclear translocation during the differentiation, while a progressive gel rupture at the cell-hydrogel interface along with a change in the gel elasticity was detected. These findings suggest that spontaneous decrosslinking of the hydrogel alters its mechanical properties, delivering mechanical stimuli to the cells. These mechanical signals activate the Piezo1 Ca2+ channel, facilitate YAP nuclear transcription via actomyosin cytoskeleton, and eventually provoke the astrocytic differentiation. While offering an efficient approach to obtain astrocytes, our work provides novel insights into the mechanism of astrocytic development through mechanical regulation.

Shared Genes and Molecular Mechanisms between Nonalcoholic Fatty Liver Disease and Hepatocellular Carcinoma Established by WGCNA Analysis

Background  Hepatocellular carcinoma (HCC) is one of the leading causes of death from cancer worldwide. The histopathological features, risk factors, and prognosis of HCC caused by nonalcoholic fatty liver disease (NAFLD) appear to be significantly different from those of HCC caused by other etiologies of liver disease. Objective  This article explores the shared gene and molecular mechanism between NAFLD and HCC through bioinformatics technologies such as weighted gene co-expression network analysis (WGCNA), so as to provide a reference for comprehensive understanding and treatment of HCC caused by NAFLD. Methods  NAFLD complementary deoxyribonucleic acid microarrays (GSE185051) from the Gene Expression Omnibus database and HCC ribonucleic acid (RNA)-sequencing data (RNA-seq data) from The Cancer Genome Atlas database were used to analyze the differentially expressed genes (DEGs) between NAFLD and HCC. Then, the clinical traits and DEGs in the two disease data sets were analyzed by WGCNA to obtain W-DEGs, and cross-W-DEGs were obtained by their intersection. We performed subsequent Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) enrichment analyses of the cross-W-DEGs and established protein-protein interaction networks. Then, we identified the hub genes in them by Cytoscape and screened out the final candidate genes. Finally, we validated candidate genes by gene expression, survival, and immunohistochemical analyses. Results  The GO analysis of 79 cross-W-DEGs showed they were related mainly to RNA polymerase II (RNAP II) and its upstream transcription factors. KEGG analysis revealed that they were enriched predominantly in inflammation-related pathways (tumor necrosis factor and interleukin-17). Four candidate genes (JUNB, DUSP1, NR4A1, and FOSB) were finally screened out from the cross-W-DEGs. Conclusion  JUNB, DUSP1, NR4A1, and FOSB inhibit NAFLD and HCC development and progression. Thus, they can serve as potential useful biomarkers for predicting and treating NAFLD progression to HCC.

Adipocyte-derived CCDC3 promotes tumorigenesis in epithelial ovarian cancer through the Wnt/ß-catenin signalling pathway

Introduction

Epithelial ovarian cancer (EOC) is a highly aggressive disease whose unique metastatic site is the omentum. Coiled-coil domain containing 3 (CCDC3) is an adipocyte-derived secreted protein that is specifically elevated in omental adipose tissue. However, its function is still unknown.

Material and methods

Initially, a Kaplan-Meier plot was applied to evaluate the prognostic value of CCDC3 expression in patients with EOC. A bioinformatics analysis was next used to explore the biological function of CCDC3 in EOC. Western blot, quantitative real-time polymerase chain reaction, and in vitro invasion and migration assays were performed using SKOV3 cells and CCDC3 secreted by rat adipocytes to analyzes the impact of CCDC3 on EOC and the underlying mechanism.

Results

Overexpression of CCDC3 was associated with poor prognosis of EOC. CCDC3 interacted with multiple key signalling pathways, including the Wnt/β-catenin pathway. EOC cellular proliferation, migration, and invasion were promoted in vitro when co-cultured with CCDC3 enriched conditioned medium, and this tumour-promoting effect was induced by activating the Wnt/β-catenin pathway. Furthermore, the epithelial-mesenchymal transition of EOC cells was reversed after CCDC3 silencing.

Conclusions

Our results support that CCDC3 promotes EOC tumorigenesis through the Wnt/β-catenin pathway and that CCDC3 may serve as a novel prognostic biomarker and therapeutic target for metastatic EOC.

New Opportunities to Individualize Frontline Therapy in Advanced Stages of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a leading cause of cancer death globally and is rising in incidence. Until recently, treatment options for patients with advanced stages of HCC have been limited to antiangiogenic therapies with modest improvements in overall survival. The emerging role of immunotherapy with immune checkpoint inhibitors (ICI) in oncology has led to a rapid expansion in treatment options and improvements in outcomes for patients with advanced stages of HCC. Recent clinical trials have shown meaningful survival improvement in patients treated with the combination of bevacizumab and atezolizumab, as well as with the combination of tremelimumab with durvalumab, resulting in regulatory approvals of these regimens as frontline therapy. Beyond improvements in overall survival, ICI-based combination regimens achieve higher rates of durable treatment response than multikinase inhibitors and have favorable side effect profiles. With the emergence of doublet anti-angiogenic and immune checkpoint inhibitor (ICI) and dual ICI combinations, individualized therapy is now possible for patients based on co-morbidity profiles and other factors. These more potent systemic therapies are also being tested in earlier stages of disease and in combination with loco-regional therapies such as trans-arterial chemoembolization and stereotactic body radiotherapy. We summarize these advances and emerging therapeutic combinations currently in clinical trials.

JCAD promotes arterial thrombosis through PI3K/Akt modulation: a translational study

AIMS

Variants of the junctional cadherin 5 associated (JCAD) locus associate with acute coronary syndromes. JCAD promotes experimental atherosclerosis through the large tumor suppressor kinase 2 (LATS2)/Hippo pathway. This study investigates the role of JCAD in arterial thrombosis.

METHODS AND RESULTS

JCAD knockout (Jcad-/-) mice underwent photochemically induced endothelial injury to trigger arterial thrombosis. Primary human aortic endothelial cells (HAECs) treated with JCAD small interfering RNA (siJCAD), LATS2 small interfering RNA (siLATS2) or control siRNA (siSCR) were employed for in vitro assays. Plasma JCAD was measured in patients with chronic coronary syndrome or ST-elevation myocardial infarction (STEMI). Jcad-/- mice displayed reduced thrombogenicity as reflected by delayed time to carotid occlusion. Mechanisms include reduced activation of the coagulation cascade [reduced tissue factor (TF) expression and activity] and increased fibrinolysis [higher thrombus embolization episodes and D-dimer levels, reduced vascular plasminogen activator inhibitor (PAI)-1 expression]. In vitro, JCAD silencing inhibited TF and PAI-1 expression in HAECs. JCAD-silenced HAECs (siJCAD) displayed increased levels of LATS2 kinase. Yet, double JCAD and LATS2 silencing did not restore the control phenotype. si-JCAD HAECs showed increased levels of phosphoinositide 3-kinases (PI3K)/ proteinkinase B (Akt) activation, known to downregulate procoagulant expression. The PI3K/Akt pathway inhibitor-wortmannin-prevented the effect of JCAD silencing on TF and PAI-1, indicating a causative role. Also, co-immunoprecipitation unveiled a direct interaction between JCAD and Akt. Confirming in vitro findings, PI3K/Akt and P-yes-associated protein levels were higher in Jcad-/- animals. Lastly, as compared with chronic coronary syndrome, STEMI patients showed higher plasma JCAD, which notably correlated positively with both TF and PAI-1 levels.

CONCLUSIONS

JCAD promotes arterial thrombosis by modulating coagulation and fibrinolysis. Herein, reported translational data suggest JCAD as a potential therapeutic target for atherothrombosis.

Pathogenesis and treatment of non-alcoholic steatohepatitis and its fibrosis

The initial presentation of non-alcoholic steatohepatitis (NASH) is hepatic steatosis. The dysfunction of lipid metabolism within hepatocytes caused by genetic factors, diet, and insulin resistance causes lipid accumulation. Lipotoxicity, oxidative stress, mitochondrial dysfunction, and endoplasmic reticulum stress would further contribute to hepatocyte injury and death, leading to inflammation and immune dysfunction in the liver. During the healing process, the accumulation of an excessive amount of fibrosis might occur while healing. During the development of NASH and liver fibrosis, the gut-liver axis, adipose-liver axis, and renin-angiotensin system (RAS) may be dysregulated and impaired. Translocation of bacteria or its end-products entering the liver could activate hepatocytes, Kupffer cells, and hepatic stellate cells, exacerbating hepatic steatosis, inflammation, and fibrosis. Bile acids regulate glucose and lipid metabolism through Farnesoid X receptors in the liver and intestine. Increased adipose tissue-derived non-esterified fatty acids would aggravate hepatic steatosis. Increased leptin also plays a role in hepatic fibrogenesis, and decreased adiponectin may contribute to hepatic insulin resistance. Moreover, dysregulation of peroxisome proliferator-activated receptors in the liver, adipose, and muscle tissues may impair lipid metabolism. In addition, the RAS may contribute to hepatic fatty acid metabolism, inflammation, and fibrosis. The treatment includes lifestyle modification, pharmacological therapy, and non-pharmacological therapy. Currently, weight reduction by lifestyle modification or surgery is the most effective therapy. However, vitamin E, pioglitazone, and obeticholic acid have also been suggested. In this review, we will introduce some new clinical trials and experimental therapies for the treatment of NASH and related fibrosis.

Epidemiologic, Genetic, Pathogenic, Metabolic, Epigenetic Aspects Involved in NASH-HCC: Current Therapeutic Strategies

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and is the sixth most frequent cancer in the world, being the third cause of cancer-related deaths. Nonalcoholic steatohepatitis (NASH) is characterized by fatty infiltration, oxidative stress and necroinflammation of the liver, with or without fibrosis, which can progress to advanced liver fibrosis, cirrhosis and HCC. Obesity, metabolic syndrome, insulin resistance, and diabetes exacerbates the course of NASH, which elevate the risk of HCC. The growing prevalence of obesity are related with increasing incidence of NASH, which may play a growing role in HCC epidemiology worldwide. In addition, HCC initiation and progression is driven by reprogramming of metabolism, which indicates growing appreciation of metabolism in the pathogenesis of this disease. Although no specific preventive pharmacological treatments have recommended for NASH, dietary restriction and exercise are recommended. This review focuses on the molecular connections between HCC and NASH, including genetic and risk factors, highlighting the metabolic reprogramming and aberrant epigenetic alterations in the development of HCC in NASH. Current therapeutic aspects of NASH/HCC are also reviewed.

GPM6A expression is suppressed in hepatocellular carcinoma through miRNA-96 production

GPM6A is a glycoprotein in endothelial cells, and its biological function in the development of hepatocellular carcinoma (HCC) is unknown. Through Affymetrix gene expression microarray and bioinformatic analysis, very low GPM6A expression was found in HCC tissue. The present study aims to explore the function and regulatory mechanism of GPM6A in HCC development and progression. Levels of GPM6A expression in HCC specimens from different disorders and various hepatoma cell lines were determined, and its role on cell proliferation was evaluated in hepatoma cells stably overexpressing GPM6A. Modulation of a specific microRNA (miRNA) on its expression and function was evaluated with miRNA mimetic transfection. Herein, it is reported that much lower GPM6A levels were found in HCC tissues than pericancerous liver tissues and correlated to a poor prognosis. GPM6A overexpression inhibited cell proliferation, suppressed colony formation, migration and invasion in two hepatoma cell types. Available evidence does not support that genetic and epigenetic dysregulation contributes significantly to GPM6A inactivation in HCC. Additional findings demonstrated that miR-96-5p acted directly on the 3'-UTR of the GPM6A gene and significantly decreased its mRNA and protein levels. MiR-96-5p transfection promoted proliferation, migration and invasion of SMMC-7721 and MHCC-97H hepatoma cells; whereas the function of oncogenic microRNA-96 was significantly inhibited in GPM6A-overexpressed hepatoma cells. In conclusion, GPM6A expression in HCC is commonly suppressed regardless its base disease types, and its low expression in HCC tissues is most likely attributed to upregulated miR-96-5p. GPM6A may function as a valuable biomarker for HCC progression and prognosis.

NEK2 inactivates the Hippo pathway to advance the proliferation of cervical cancer cells by cooperating with STRIPAK complexes

The never in mitosis gene A (NIMA)-related kinase 2 (NEK2) protein has been reported to be an oncoprotein that plays different oncogenic roles in multiple cancers. Here, we confirmed that NEK2 highly expressed in cervical cancer cells rather than in normal epithelial basal layer cells in cervical tissues and correlated with worse outcomes. We also demonstrated that NEK2 promoted the in vivo growth of subcutaneous xenograft tumors stemming from cervical cancer cells and the in vitro cell proliferation by decreasing Ser127-phosphorylation of the YAP protein retained in the cytoplasm while increasing the levels of active nucleus-associated YAP protein, which was followed by increases in the targeted proteins CTGF, CYR61 and GLI2. Furthermore, the Hippo signaling pathway was inactivated in manipulated NEK2-overexpressing cervical cancer cells by regulating the levels of MST1/2 dephosphorylation. Additionally, mass spectrometric sequencing and bilateral coimmunoprecipitation were employed suggested that NEK2 acted at an early upstream step to promote dephosphorylation of MST2 and inactivate the Hippo signaling cascade by cooperating with STRIPAK complexes. We conjecture that NEK2 may be a future target for cervical cancer therapy.

Advances in prognostic and therapeutic targets for hepatocellular carcinoma and intrahepatic cholangiocarcinoma: The hippo signaling pathway

Primary liver cancer is the sixth most frequently diagnosed cancer worldwide and the third leading cause of cancer-related death. The majority of the primary liver cancer cases are hepatocellular carcinoma and intrahepatic cholangiocarcinoma. Worldwide, there is an increasing incidence of primary liver cancer cases due to multiple risk factors ranging from parasites and viruses to metabolic diseases and lifestyles. Often, patients are diagnosed at advanced stages, depriving them of surgical curability benefits. Moreover, the efficacy of the available chemotherapeutics is limited in advanced stages. Furthermore, tumor metastases and recurrence make primary liver cancer management exceptionally challenging. Thus, exploring the molecular mechanisms for the development and progression of primary liver cancer is critical in improving diagnostic, treatment, prognostication, and surveillance modalities. These mechanisms facilitate the discovery of specific targets that are critical for novel and more efficient treatments. Consequently, the Hippo signaling pathway executing a pivotal role in organogenesis, hemostasis, and regeneration of tissues, regulates liver cells proliferation, and apoptosis. Cell polarity or adhesion molecules and cellular metabolic status are some of the biological activators of the pathway. Thus, understanding the mechanisms exhibited by the Hippo pathway is critical to the development of novel targeted therapies. This study reviews the advances in identifying therapeutic targets and prognostic markers of the Hippo pathway for primary liver cancer in the past six years.

Interplay Between Fatty Acids, Stearoyl-Co-A Desaturase, Mechanistic Target of Rapamycin, and Yes-Associated Protein/Transcriptional Coactivator With PDZ-Binding Motif in Promoting Hepatocellular Carcinoma

Nonalcoholic fatty liver disease has reached pandemic proportions with one of its most consequential complications being hepatocellular carcinoma (HCC). Nonalcoholic fatty liver disease-related HCC is becoming the leading indication for liver transplantation in the United States. Given the scarcity of available organs, early detection and prevention remain key in prevention and management of the disease. Over the years, the yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) pathway emerged as a key signal transduction pathway in the pathogenesis of HCC. In this review, we explore the interplay between the YAP/TAZ pathway as a point of convergence in HCC pathogenesis. We review the evidence of how lipid reprogramming and key lipid pathways, saturated and monounsaturated fatty acids (through the rate-limiting enzyme stearoyl Co-A desaturase), the mevalonic acid pathway (the role of statins), and mechanistic target of rapamycin all play critical roles in intricate and complex networks that tightly regulate the YAP/TAZ pro-oncogenic pathway.

Modulation of hepatic stellate cells by Mutaflor® probiotic in non-alcoholic fatty liver disease management

BACKGROUND

NAFLD and NASH are emerging as primary causes of chronic liver disease, indicating a need for an effective treatment. Mutaflor® probiotic, a microbial treatment of interest, was effective in sustaining remission in ulcerative colitis patients.

OBJECTIVE

To construct a genetic-epigenetic network linked to HSC signaling as a modulator of NAFLD/NASH pathogenesis, then assess the effects of Mutaflor^® on this network.

METHODS

First, in silico analysis was used to construct a genetic-epigenetic network linked to HSC signaling. Second, an investigation using rats, including HFHSD induced NASH and Mutaflor^® treated animals, was designed. Experimental procedures included biochemical and histopathologic analysis of rat blood and liver samples. At the molecular level, the expression of genetic (FOXA2, TEAD2, and LATS2 mRNAs) and epigenetic (miR-650, RPARP AS-1 LncRNA) network was measured by real-time PCR. PCR results were validated with immunohistochemistry (α-SMA and LATS2). Target effector proteins, IL-6 and TGF-β, were estimated by ELISA.

RESULTS

Mutaflor^® administration minimized biochemical and histopathologic alterations caused by NAFLD/NASH. HSC activation and expression of profibrogenic IL-6 and TGF-β effector proteins were reduced via inhibition of hedgehog and hippo pathways. Pathways may have been inhibited through upregulation of RPARP AS-1 LncRNA which in turn downregulated the expression of miR-650, FOXA2 mRNA and TEAD2 mRNA and upregulated LATS2 mRNA expression.

CONCLUSION

Mutaflor^® may slow the progression of NAFLD/NASH by modulating a genetic-epigenetic network linked to HSC signaling. The probiotic may be a useful modality for the prevention and treatment of NAFLD/NASH.

A derivant of ginsenoside CK and its inhibitory effect on hepatocellular carcinoma

Epidemiological studies have shown that hepatocellular carcinoma (HCC) is a main cause of tumor death worldwide. Accumulating data indicate that ginsenoside CK is an effective compound for preventing HCC growth and development. However, improvement of pharmaceutical effect of the ginsenoside CK is still needed. In our study, we performed acetylation of ginsenoside CK (CK-3) and investigated the antitumor effects of the derivative in vitro and in vivo. The cytotoxicity analysis revealed that compared with CK, CK-3 could inhibit the proliferation of multiple tumor cell lines at a lower concentration. Treating with CK-3 on HCC cells arrested cell cycle in G2/M phase and induced cell apoptosis through AO/EB staining, TUNEL analysis and flow cytometry. Meanwhile, CK-3 significantly inhibited tumor growth in an HCC xenograft model and showed no side effect on the function of the main organs. Mechanistically, whole transcriptome analysis revealed that the antitumor effect of CK-3 was involved in the Hippo signaling pathway. The immunoblotting and immunofluorescence results illustrated that CK-3 directly facilitated the phosphorylation of YAP1 and decreased the expression of the main transcription factor TEAD2 in HCC cell lines and tumor tissue sections. Collectively, our results demostrate the formation of a new derivative of ginsenoside CK and its regulatory mechanism in HCC, which could activate the Hippo-YAP1-TEAD2 signaling pathway to regulate HCC progression. This research could provide a new direction for traditional Chinese medicine in the therapy of tumors.

Regulation of Hippo signaling by metabolic pathways in cancer

Hippo signaling is known to maintain balance between cell proliferation and apoptosis via tight regulation of factors, such as metabolic cues, cell-cell contact, and mechanical cues. Cells directly recognize glucose, lipids, and other metabolic cues and integrate multiple signaling pathways, including Hippo signaling, to adjust their proliferation and apoptosis depending on nutrient conditions. Therefore, the dysregulation of the Hippo signaling pathway can promote tumor initiation and progression. Alteration in metabolic cues is considered a major factor affecting the risk of cancer formation and progression. It has recently been shown that the dysregulation of the Hippo signaling pathway, through diverse routes activated by metabolic cues, can lead to cancer with a poor prognosis. In addition, unique crosstalk between metabolic pathways and Hippo signaling pathways can inhibit the effect of anticancer drugs and promote drug resistance. In this review, we describe an integrated perspective of the relationship between the Hippo signaling pathway and metabolic signals in the context of cancer. We also characterize the mechanisms involved in changes in metabolism that are linked to the Hippo signaling pathway in the cancer microenvironment and propose several novel targets for anticancer drug treatment.

Dihydroartemisinin reduced lipid droplet deposition by YAP1 to promote the anti-PD-1 effect in hepatocellular carcinoma

BACKGROUND

Anti-PD-1 was used to treat for many cancers, but the overall response rate of monoclonal antibodies blocking the inhibitory PD-1/PD-L1 was less than 20%. Lipid droplet (LD) deposition reduced chemotherapy efficacy, but whether LD deposition affects anti-PD-1 treatment and its mechanism remains unclear. Dihydroartemisinin (DHA) was FDA proved antimalarial medicine, but its working mechanism on LD deposition has not been clarified.

PURPOSE

This study aimed to elucidate the mechanism of DHA reducing LDs deposition and improving the efficacy of anti-PD-1.

METHODS

LD numbers and area were separately detected by electron microscopy and oil Red O staining. The expression of YAP1 and PLIN2 was detected by immunohistochemical staining in liver cancer tissues. Transcription and protein expression levels of YAP1 and PLIN2 in cells were detected by qRT-PCR and Western blot after DHA treated HepG2215 cells and Yap1^LKO mice.

RESULTS

LD accumulation was found in the liver tumor cells of DEN/TOPBCOP-induced liver tumor mice with anti-PD-1 treatment. But DHA treatment or YAP1 knockdown reduced LD deposition and PLIN2 expression in HepG2215 cells. Furthermore, DHA reduced the LD deposition, PLIN2 expression and triglycerides (TG) content in the liver tumor cells of Yap1^LKO mice with liver tumor.

CONCLUSION

Anti-PD-1 promoted LD deposition, while YAP1 knockdown/out reduced LD deposition in HCC. DHA reduced LD deposition by inhibiting YAP1, enhancing the effect of anti-PD-1 therapy.

USP8 regulates liver cancer progression via the inhibition of TRAF6-mediated signal for NF-κB activation and autophagy induction by TLR4

Herein, we aimed to elucidate the molecular and cellular mechanism in which ubiquitin-specific protease 8 (USP8) is implicated in liver cancer progression via TRAF6-mediated signal. USP8 induces the deubiquitination of TRAF6, TAB2, TAK1, p62, and BECN1, which are pivotal roles for NF-κB activation and autophagy induction. Notably, the LIHC patient with low USP8 mRNA expression showed markedly shorter survival time, whereas there was no significant difference in the other 18-human cancers. Importantly, the TCGA data analysis on LIHC and transcriptome analysis on the USP8 knockout (USP8KO) SK-HEP-1 cells revealed a significant correlation between USP8 and TRAF6, TAB2, TAK1, p62, and BECN1, and enhanced NF-κB-dependent and autophagy-related cancer progression/metastasis-related genes in response to LPS stimulation. Furthermore, USP8KO SK-HEP-1 cells showed an increase in cancer migration and invasion by TLR4 stimulation, and a marked increase of tumorigenicity and metastasis in xenografted NSG mice. The results demonstrate that USP8 is negatively implicated in the LIHC progression through the regulation of TRAF6-mediated signal for the activation of NF-κB activation and autophagy induction. Our findings provide useful insight into the LIHC pathogenesis of cancer progression.

The YAP/TAZ Signaling Pathway in the Tumor Microenvironment and Carcinogenesis: Current Knowledge and Therapeutic Promises

The yes-associated protein (YAP) and the transcriptional coactivator with PDZ-binding motif (TAZ) are transcriptional coactivators, members of the Hippo signaling pathway, which play a critical role in cell growth regulation, embryonic development, regeneration, proliferation, and cancer origin and progression. The mechanism involves the nuclear binding of the un-phosphorylated YAP/TAZ complex to release the transcriptional enhanced associate domain (TEAD) from its repressors. The active ternary complex is responsible for the aforementioned biological effects. Overexpression of YAP/TAZ has been reported in cancer stem cells and tumor resistance. The resistance involves chemotherapy, targeted therapy, and immunotherapy. This review provides an overview of YAP/TAZ pathways’ role in carcinogenesis and tumor microenvironment. Potential therapeutic alternatives are also discussed.

Probiotic-prebiotic-synbiotic modulation of (YAP1, LATS1 and NF2 mRNAs/miR-1205/lncRNA SRD5A3-AS1) panel in NASH animal model

AIM

To investigate the prophylactic efficacy of gut microbiota-based treatments on nonalcoholic steatohepatitis (NASH) management via modulation of Hippo signaling pathway-related genes (YAP1, LATS1 and NF2), and their epigenetic regulators (miR-1205 and lncRNA SRD5A3-AS1) retrieved from in-silico data analysis.

MATERIALS & METHODS

Histopathological, biochemical, molecular and immunohistochemistry analyses were used to assess the effects of multistrain probiotic mixture and prebiotic inulin fiber on high sucrose high fat (HSHF) diet-induced NASH in rats. These treatments were administered orally either alone or in combination, along with HSHF diet.

RESULTS

Both probiotic mixture and prebiotic inulin fiber attenuated steatosis, inflammation and fibrosis grades in HSHF diet-induced NASH rats. Moreover, the applied treatments significantly prevented the elevation of serum liver enzymes and improved lipid panel. At the molecular level, both treatments down-regulated hepatic YAP1 mRNA and miR-1205 expressions, and concomitantly up-regulated the expression of hepatic LATS1& NF2 mRNAs and the lncRNA SRD5A3-AS1. At the protein level, both treatments decreased the hepatic content of the inflammatory marker IL6 and the fibrotic marker TGFβ1. Moreover, an observable reduction in α-SMA together with noticeable elevation in LATS1/2 protein expression levels were detected in liver sections compared to the untreated rats.

CONCLUSION

Probiotic mixture and prebiotic inulin fiber, either alone or in combination, attenuated NASH progression and ameliorated both fibrosis and hepatic inflammation in the applied animal model. The produced effect was correlated with modulation of the retrieved (YAP1, LATS1 and NF2) - (miR-1205) - (lncRNA SRD5A3-AS1) RNA panel.

mRNA-miRNA-lncRNA Regulatory Network in Nonalcoholic Fatty Liver Disease

AIM

we aimed to construct a bioinformatics-based co-regulatory network of mRNAs and non coding RNAs (ncRNAs), which is implicated in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), followed by its validation in a NAFLD animal model.

MATERIALS AND METHODS

The mRNAs-miRNAs-lncRNAs regulatory network involved in NAFLD was retrieved and constructed utilizing bioinformatics tools. Then, we validated this network using an NAFLD animal model, high sucrose and high fat diet (HSHF)-fed rats. Finally, the expression level of the network players was assessed in the liver tissues using reverse transcriptase real-time polymerase chain reaction.

RESULTS

in-silico constructed network revealed six mRNAs (YAP1, FOXA2, AMOTL2, TEAD2, SMAD4 and NF2), two miRNAs (miR-650 and miR-1205), and two lncRNAs (RPARP-AS1 and SRD5A3-AS1) that play important roles as a co-regulatory network in NAFLD pathogenesis. Moreover, the expression level of these constructed network-players was significantly different between NAFLD and normal control. Conclusion and future perspectives: this study provides new insight into the molecular mechanism of NAFLD pathogenesis and valuable clues for the potential use of the constructed RNA network in effective diagnostic or management strategies of NAFLD.

NLRP3 deficiency did not attenuate NASH development under high fat calorie diet plus high fructose and glucose in drinking water

NOD-like receptor protein 3 (NLRP3) promotes the inflammatory response during progression of nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH). This study aimed to further delineate the role of NLRP3 in NASH development by abolishing its expression in mice. A high-fat and calorie diet plus high fructose and glucose in drinking water (HFCD-HF/G) was used to establish NASH in both wild-type (WT) and NLRP3 knock-out (KO) mice. Hepatocellular injury, hepatic steatosis and fibrosis, as well as inflammatory response and insulin resistance in the liver and epidydimal white adipose tissue (eWAT) were determined. Elevated body weight, liver weight and serum alanine transaminase level, increased hepatic triglyceride accumulation and collagen deposition, and worsened systemic insulin resistance were observed in Nlrp3-/- mice compared to WT mice under HFCD-HF/G feeding. Upregulated hepatic transcription of tumor necrosis factor-α (TNF-α) and monocyte chemotactic protein-1 (MCP-1), and enhanced infiltration of inducible nitric oxide synthase-positive (iNOS+) M1 macrophages were also documented in HFCD-HF/G-fed Nlrp3-/- mice in comparison to HFCD-HF/G-fed WT mice. Moreover, transcription of TNF-α and MCP-1 and infiltration of iNOS+ M1 macrophages were increased in the liver of Nlrp3-/- mice under control diet. NLRP3 deficiency did not attenuate, but instead aggravated NASH development under HFCD-HF/G feeding. The worsened extent of NASH might be attributed to enhanced hepatic MCP-1 expression and M1 macrophage infiltration in Nlrp3-/- mice. Our study points to additional caution when NLRP3 blockade is considered as a therapeutic strategy in the treatment of human NASH.

Molecular Mechanisms Linking Nonalcoholic Steatohepatitis to Cancer

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Integration of Hippo-YAP Signaling with Metabolism

The Hippo-Yes-associated protein (YAP) signaling network plays a central role as an integrator of signals that control cellular proliferation and differentiation. The past several years have provided an increasing appreciation and understanding of the diverse mechanisms through which metabolites and metabolic signals influence Hippo-YAP signaling, and how Hippo-YAP signaling, in turn, controls genes that direct cellular and organismal metabolism. These connections enable Hippo-YAP signaling to coordinate organ growth and homeostasis with nutrition and metabolism. In this review, we discuss the current understanding of some of the many interconnections between Hippo-YAP signaling and metabolism and how they are affected in disease conditions.

Hedgehog Signaling, a Critical Pathway Governing the Development and Progression of Hepatocellular Carcinoma

Hedgehog (Hh) signaling is a classic morphogen in controlling embryonic development and tissue repairing. Aberrant activation of Hh signaling has been well documented in liver cancer, including hepatoblastoma, hepatocellular carcinoma (HCC) and cholangiocarcinoma. The present review aims to update the current understanding on how abnormal Hh signaling molecules modulate initiation, progression, drug resistance and metastasis of HCC. The latest relevant literature was reviewed with our recent findings to provide an overview regarding the molecular interplay and clinical relevance of the Hh signaling in HCC management. Hh signaling molecules are involved in the transformation of pre-carcinogenic lesions to malignant features in chronic liver injury, such as nonalcoholic steatohepatitis. Activation of GLI target genes, such as ABCC1 and TAP1, is responsible for drug resistance in hepatoma cells, with a CD133⁻/EpCAM⁻ surface molecular profile, and GLI1 and truncated GLI1 account for the metastatic feature of the hepatoma cells, with upregulation of matrix metalloproteinases. A novel bioassay for the Sonic Hh ligand in tissue specimens may assist HCC diagnosis with negative α-fetoprotein and predict early microvascular invasion. In-depth exploration of the Hh signaling deepens our understanding of its molecular modulation in HCC initiation, drug sensitivity and metastasis, and guides precise management of HCC on an individual basis.

Hypermethylation of LATS2 Promoter and Its Prognostic Value in IDH-Mutated Low-Grade Gliomas

Mutations in the enzyme isocitrate dehydrogenase 1/2 (IDH1/2) are the most common somatic mutations in low-grade glioma (LGG). The Hippo signaling pathway is known to play a key role in organ size control, and its dysregulation is involved in the development of diverse cancers. Large tumor suppressor 1/2 (LATS1/2) are core Hippo pathway components that phosphorylate and inactivate Yes-associated protein (YAP), a transcriptional co-activator that regulates expression of genes involved in tumorigenesis. A recent report from The Cancer Genome Atlas (TCGA) has highlighted a frequent hypermethylation of LATS2 in IDH-mutant LGG. However, it is unclear if LATS2 hypermethylation is associated with YAP activation and prognosis of LGG patients. Here, we performed a network analysis of the status of the Hippo pathway in IDH-mutant LGG samples and determined its association with cancer prognosis. Combining TCGA data with our biochemical assays, we found hypermethylation of LATS2 promoter in IDH-mutant LGG. LATS2 hypermethylation, however, did not translate into YAP activation but highly correlated with IDH mutation. LATS2 hypermethylation may thus serve as an alternative for IDH mutation in diagnosis and a favorable prognostic factor for LGG patients.

JCAD expression and localization in human blood endothelial cells

Background

Junctional Cadherin 5 Associated (JCAD) is an endothelial, cell-cell junction protein, and its expression is associated with cardiovascular diseases including atherosclerosis and hypertension. However, to date, there are few studies confirming JCAD expression and precise localization in human tissues by immunohistochemical staining.

Methods

JCAD expression and localization was assessed in four human submandibular gland (SMG) specimens by immunohistochemical staining. One specimen of SMG with sialoadenitis was accompanied by severe inflammation and fibrosis, while the other was largely normal. Other two SMGs were accompanied by severe fibrosis because of irradiation.

Results

Immunohistochemical analysis of human SMGs revealed JCAD localization at the blood endothelial cell-cell junctions. JCAD expression was more evident in microvessels and arteries in areas affected by inflammation.

Conclusions

The localization of JCAD at endothelial cell-cell junctions was confirmed in human tissues. JCAD expression may be affected by pathological conditions.

Hepatic Hippo signaling inhibits development of hepatocellular carcinoma

Primary liver cancer is one of the most common cancer worldwide. Hepatocellular carcinoma (HCC) in particular, is the second leading cause of cancer deaths in the world. The Hippo signaling pathway has emerged as a major oncosuppressive pathway that plays critical roles inhibiting hepatocyte proliferation, survival, and HCC formation. A key component of the Hippo pathway is the inhibition of yes-associated protein (YAP)/transcriptional co-activator with PDZ-binding motif (TAZ) transcription factors by the Hippo kinase cascade. Aberrant activation of YAP or TAZ has been found in several human cancers including HCC. It is also well established that YAP/TAZ activation in hepatocytes causes HCC in mouse models, indicating that YAP/TAZ are potential therapeutic targets for human liver cancer. In this review, we summarize the recent findings regarding the multifarious roles of Hippo/YAP/TAZ in HCC development, and focus on their cell autonomous roles in controlling hepatocyte proliferation, differentiation, survival and metabolism as well as their non-cell autonomous in shaping the tumor microenvironment.

A key role for the novel coronary artery disease gene JCAD in atherosclerosis via shear stress mechanotransduction

AIMS

Genome-wide association studies (GWAS) have consistently identified an association between coronary artery disease (CAD) and a locus on chromosome 10 containing a single gene, JCAD (formerly KIAA1462). However, little is known about the mechanism by which JCAD could influence the development of atherosclerosis.

METHODS AND RESULTS

Vascular function was quantified in subjects with CAD by flow-mediated dilatation (FMD) and vasorelaxation responses in isolated blood vessel segments. The JCAD risk allele identified by GWAS was associated with reduced FMD and reduced endothelial-dependent relaxations. To study the impact of loss of Jcad on atherosclerosis, Jcad-/- mice were crossed to an ApoE-/- background and fed a high-fat diet from 6 to16 weeks of age. Loss of Jcad did not affect blood pressure or heart rate. However, Jcad-/-ApoE-/- mice developed significantly less atherosclerosis in the aortic root and the inner curvature of the aortic arch. En face analysis revealed a striking reduction in pro-inflammatory adhesion molecules at sites of disturbed flow on the endothelial cell layer of Jcad-/- mice. Loss of Jcad lead to a reduced recovery perfusion in response to hind limb ischaemia, a model of altered in vivo flow. Knock down of JCAD using siRNA in primary human aortic endothelial cells significantly reduced the response to acute onset of flow, as evidenced by reduced phosphorylation of NF-КB, eNOS, and Akt.

CONCLUSION

The novel CAD gene JCAD promotes atherosclerotic plaque formation via a role in the endothelial cell shear stress mechanotransduction pathway.

Lack of FGF21 promotes NASH-HCC transition via hepatocyte-TLR4-IL-17A signaling

Rationale: Hepatocellular carcinoma (HCC) has been increasingly recognized in nonalcoholic steatohepatitis (NASH) patients. Fibroblast growth factor 21 (FGF21) is reported to prevent NASH and delay HCC development. In this study, the effects of FGF21 on NASH progression and NASH-HCC transition and the potential mechanism(s) were investigated. Methods: NASH models and NASH-HCC models were established in FGF21Knockout (KO) mice to evaluate NASH-HCC transition. IL-17A signaling was investigated in the isolated hepatic parenchymal cells, splenocytes, and hepatocyte and HCC cell lines. Results: Lack of FGF21 caused significant up-regulation of the hepatocyte-derived IL-17A via Toll-like receptor 4 (TLR4) and NF-κB signaling. Restoration of FGF21 alleviated the high NAFLD activity score (NAS) and attenuated the TLR4-triggered hepatocyte-IL-17A expression. The HCC nodule number and tumor size were significantly alleviated by treatments of anti-IL-17A antibody. Conclusion: This study revealed a novel anti-inflammatory mechanism of FGF21 via inhibiting the hepatocyte-TLR4-IL-17A signaling in NASH-HCC models. The negative feedback loop on the hepatocyte-TLR4-IL-17A axis could be a potential anti-carcinogenetic mechanism for FGF21 to prevent NASH-HCC transition.

The Hippo Pathway and YAP Signaling: Emerging Concepts in Regulation, Signaling, and Experimental Targeting Strategies With Implications for Hepatobiliary Malignancies

The Hippo pathway and its effector protein YAP (a transcriptional coactivator) have been identified as important in the biology of both hepatocellular carcinoma and cholangiocarcinoma. First identified as a tumor suppressor pathway in Drosophila, the understanding of the mammalian YAP signaling and its regulation continues to expand. In its "on" function, the canonical regulatory Hippo pathway, a well-described serine/threonine kinase module, regulates YAP function by restricting its subcellular localization to the cytoplasm. In contrast, when the Hippo pathway is "off," YAP translocates to the nucleus and drives cotranscriptional activity. Given the role of Hippo/YAP signaling in hepatic malignancies, investigators have sought to target these molecules; however, standard approaches have not been successful based on the pathways' negative regulatory role. More recently, additional regulatory mechanisms, such as tyrosine phosphorylation, of YAP have been described. These represent positive regulatory events that may be targetable. Additionally, several groups have identified potentiating feed-forward signaling for YAP in multiple contexts, suggesting other experimental therapeutic approaches to interrupt these signaling loops. Herein we explore the current data supporting alternative YAP regulatory pathways, review the described feed-forward signaling cascades that are YAP dependent, and explore targeting strategies that have been employed in preclinical models of hepatic malignancies.

Transcription activation of circ-STAT3 induced by Gli2 promotes the progression of hepatoblastoma via acting as a sponge for miR-29a/b/c-3p to upregulate STAT3/Gli2

BACKGROUND

Hepatoblastoma (HB) is a common liver malignancy in children. Our previous study has disclosed the crucial role of STAT3 (signal transducer and activator of transcription 3) in HB.

AIM OF THE STUDY

Present study was designed to study the circular RNA (circRNA) STAT3 in HB.

METHODS

Gel electrophoresis revealed the circular characteristics of circ-STAT3. Function assays like EdU, transwell and sphere formation assay disclosed the function of circ-STAT3 in HB cells. Mechanism assays including ChIP, RIP, RNA pull down assay demonstrated the macular mechanism underlying circ-STAT3.

RESULTS

Circ_0043800, which was originated from STAT3, was up-regulated in HB tissues and cells. More importantly, silencing of circ-STAT3 led to the inhibition on HB cell growth, migration and stem-cell characteristics. Circ_0043800 was predominantly located in the cytoplasm of HB cells. Then, circ_0043800 was found to up-regulate STAT3 via sponging miR-29a/b/c-3p. Besides, we identified that STAT3 overexpression partially rescued silenced circ_0043800, while miR-29a/b/c-3p inhibition completely rescued silenced circ_0043800 on HB cellular biological behaviors. Subsequently, Gli2 (GLI family zinc finger 2) was identified as another target of miR-29a/b/c-3p. Circ_0043800 served as a competing endogenous RNA (ceRNA) to up-regulate both Gli2 and STAT3 via sponging miR-29a/b/c-3p. Moreover, we figured out that Gli2 overexpression completely rescued silenced circ_0043800 on HB cell malignant behaviors. After that, we discovered that Gli2 transcriptionally activated circ_0043800. The in-vivo assays further revealed that circ_0043800 promoted HB tumor growth by up-regulation of Gli2 and STAT3.

CONCLUSION

Gli2-induced circ_0043800 served as the ceRNA to promote HB by up-regulation of STAT3 and Gli2 at a miR-29a/b/c-3p dependent manner.

ACADL plays a tumor-suppressor role by targeting Hippo/YAP signaling in hepatocellular carcinoma

Long-chain acyl-CoA dehydrogenase (ACADL) is a mitochondrial enzyme that catalyzes the initial step of fatty acid oxidation, but the role of ACADL in tumor biology remains largely unknown. Here, we found that ACADL was frequently downregulated in hepatocellular carcinoma (HCC), and its low expression was significantly correlated with poor clinical prognosis of HCC patients. Restoring the expression of ACADL in HCC cells resulted cell cycle arrest and growth suppression through suppressing Hippo/YAP signaling evidenced by decreased YAP nuclear accumulation and downstream target genes expression. Reactivation of YAP by XMU-MP-1 diminished the inhibitory effect of ACADL on HCC growth. More importantly, the nuclear accumulation of YAP was negatively correlated with ACADL expression levels in HCC specimens, and YAP inhibitor verteporfin effectively suppressed growth of HCC organoids with low ACADL expression. Together, our findings highlight a novel function of ACADL in regulating HCC growth and targeting ACADL/Yap may be a potential strategy for HCC precise treatment.

Hedgehog signalling mediates drug resistance through targeting TAP1 in hepatocellular carcinoma

Multidrug resistance is one of the reasons for low survival of advanced hepatocellular carcinoma (HCC). Our previous studies indicate that the hedgehog signalling is involved in hepatic carcinogenesis, metastasis and chemo‐resistance. The present study aims to uncover molecular mechanisms underlying hepatoma chemo‐resistance. TAP1 and GLI1/2 gene expression was assessed in both poorly differentiated hepatoma cells and HCC specimens. Potential GLI‐binding site in the TAP1 promoter sequence was validated by molecular assays. Approximately 75% HCC specimens exhibited an elevated expression of hedgehog GLI1 transcription factor compared with adjacent liver tissue. Both GLI1/2 and TAP1 protein levels were significantly elevated in poorly differentiated hepatoma cells. Both Huh‐7‐trans and Huh‐7‐DN displayed more karyotypic abnormalities and differential gene expression profiles than their native Huh‐7 cells. Sensitivity to Sorafenib, doxorubicin and cisplatin was remarkably improved after either GLI1 or TAP1 gene was inhibited by an RNAi approach or by a specific GLI1/2 inhibitor, GANT61. Further experiments confirmed that hedgehog transcription factor GLI1/2 binds to the TAP1 promoter, indicating that TAP1 is one of GLI1/2 target genes. In conclusion, TAP1 is under direct transcriptional control of the hedgehog signalling. Targeting hedgehog signalling confers a novel insight into alleviating drug resistance in the treatment of refractory HCC.

The novel coronary artery disease risk gene JCAD/KIAA1462 promotes endothelial dysfunction and atherosclerosis

AIMS

Recent genome-wide association studies (GWAS) have identified that the JCAD locus is associated with risk of coronary artery disease (CAD) and myocardial infarction (MI). However, the mechanisms whereby candidate gene JCAD confers disease risk remain unclear. We addressed whether and how JCAD affects the development of atherosclerosis, the common cause of CAD.

METHODS AND RESULTS

By mining data in the Genotype-Tissue Expression (GTEx) database, we found that CAD-associated risk variants at the JCAD locus are linked to increased JCAD gene expression in human arteries, implicating JCAD as a candidate causal CAD gene. We therefore generated global and endothelial cell (EC) specific-JCAD knockout mice, and observed that JCAD deficiency attenuated high fat diet-induced atherosclerosis in ApoE-deficient mice. JCAD-deficiency in mice also improved endothelium-dependent relaxation. Genome-wide transcriptional profiling of JCAD-depleted human coronary artery ECs showed that JCAD depletion inhibited the activation of YAP/TAZ pathway, and the expression of downstream pro-atherogenic genes, including CTGF and Cyr61. As a result, JCAD-deficient ECs attracted fewer monocytes in response to lipopolysaccharide (LPS) stimulation. Moreover, JCAD expression in ECs was decreased under unidirectional laminar flow in vitro and in vivo. Proteomics studies suggest that JCAD regulates YAP/TAZ activation by interacting with actin-binding protein TRIOBP, thereby stabilizing stress fiber formation. Finally, we observed that endothelial JCAD expression was increased in mouse and human atherosclerotic plaques.

CONCLUSION

The present study demonstrates that the GWAS-identified CAD risk gene JCAD promotes endothelial dysfunction and atherosclerosis, thus highlighting the possibility of new therapeutic strategies for CAD by targeting JCAD.

JCAD, a Gene at the 10p11 Coronary Artery Disease Locus, Regulates Hippo Signaling in Endothelial Cells

Objective- A large number of genetic loci have been associated with risk of coronary artery disease (CAD) through genome-wide association studies, however, for most loci the underlying biological mechanism is unknown. Determining the molecular pathways and cellular processes affected by these loci will provide new insights into CAD pathophysiology and may lead to new therapies. The CAD-associated variants at 10p11.23 fall in JCAD, which encodes an endothelial junction protein, however, its molecular function in endothelial cells is not known. In this study, we characterize the molecular role of JCAD (junctional cadherin 5 associated) in endothelial cells. Approach and Results- We show that JCAD knockdown in endothelial cells affects key phenotypes related to atherosclerosis including proliferation, migration, apoptosis, tube formation, and monocyte binding. We demonstrate that JCAD interacts with LATS2 (large tumor suppressor kinase 2) and negatively regulates Hippo signaling leading to increased activity of YAP (yes-associated protein), the transcriptional effector of the pathway. We also show by double siRNA knockdown that the phenotypes caused by JCAD knockdown require LATS2 and that JCAD is involved in transmission of RhoA-mediated signals into the Hippo pathway. In human tissues, we find that the CAD-associated lead variant, rs2487928, is associated with expression of JCAD in arteries, including atherosclerotic arteries. Gene co-expression analyses across disease-relevant tissues corroborate our phenotypic findings and support the link between JCAD and Hippo signaling. Conclusions- Our results show that JCAD negatively regulates Hippo signaling in endothelial cells and we suggest that JCAD contributes to atherosclerosis by mediating YAP activity and contributing to endothelial dysfunction.

Impaired mitophagy triggers NLRP3 inflammasome activation during the progression from nonalcoholic fatty liver to nonalcoholic steatohepatitis

Activation of inflammation is an important mechanism in the development of nonalcoholic steatohepatitis (NASH). This study aims to delineate how mitophagy affects NLRP3 inflammasome activation in hepatic lipotoxicity. Mice were fed a high fat/calorie diet (HFCD) for 24 weeks. Primary rat hepatocytes were treated with palmitic acid (PA) for various periods of time. Mitophagy was measured by protein levels of LC3II and P62. NLRP3, caspase-1, interleukin (IL)-18, and IL-1β at mRNA and protein levels were used as indicators of inflammasome activation. Along with steatotic progression in HFCD-fed mice, ratio of LC3II/β-actin was decreased concurrently with increased levels of liver P62, NLRP3, caspase-1, IL-1β, IL-18, and serum IL-1β levels in late-stage NASH. PA treatment resulted in mitochondrial oxidative stress and initiated mitophagy in primary hepatocytes. The addition of cyclosporine A did not change LC3II/Τοmm20 ratios; but P62 levels were increased after an extended duration of PA exposure, indicating a defect in autophagic activity. Along with impaired mitophagy, mRNA and protein levels of NLRP3, caspase-1, IL-18 and IL-1β were upregulated by PA treatment. Pretreatment with MCC950, N-acetyl cysteine or acetyl-L-carnitine reversed inflammasome activation and a pyroptotic cascade. Additionally, mitophagic flux was partially recovered as indicated by increases in LC3II/Tomm20 ratio, parkin, and PINK1 expression, and decreased P62 expression. The findings suggest that impaired mitophagy triggers hepatic NLRP3 inflammasome activation in a murine NASH model and primary hepatocytes. The new insights into inflammasome activation through mitophagy advance our understanding of how fatty acids elicit lipotoxicity through oxidant stress and autophagy in mitochondria.

Hippo Signaling in the Liver - A Long and Ever-Expanding Story

The first description of Hippo signaling in mammals a little more than 10 years ago showed a striking phenotype in the liver, linking the role of this signaling pathway to organ size control and carcinogenesis. Even though Hippo signaling has been extensively studied in the liver and other organs over the recent years, many open questions remain in our understanding of its role in hepatic physiology and disease. The functions of Hippo signaling extend well beyond cancer and organ size determination: components of upstream Hippo signaling and the downstream effectors YAP and TAZ are involved in a multitude of cell and non-cell autonomous functions including cell proliferation, survival, development, differentiation, metabolism, and cross-talk with the immune system. Moreover, regulation and biological functions of Hippo signaling are often organ or even cell type specific – making its role even more complex. Here, we give a concise overview of the role of Hippo signaling in the liver with a focus on cell-type specific functions. We outline open questions and future research directions that will help to improve our understanding of this important pathway in liver disease.