Toll-like receptor 4 mediates synergism between alcohol and HCV in hepatic oncogenesis involving stem cell marker Nanog. Proc Natl Acad Sci U S A. 2009;106:1548-1553. [PMID: 19171902 DOI: 10.1073/pnas.0807390106]

Advances in the Pathogenesis of Metabolic Liver Disease-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common cancer globally and the primary cause of death in cancer cases, with significant public health concern worldwide. Despite the overall decline in the incidence and mortality rates of HCC in recent years in recent years, the emergence of metabolic liver disease-related HCC is causing heightened concern, especially in countries like the United States, the United Kingdom, and P.R. China. The escalation of metabolic liver disease-related HCC is attributed to a combination of factors, including genetic predisposition, lifestyle choices, and changes in the living environment. However, the pathogenesis of metabolic liver disease-associated HCC remains imperfect. In this review, we encapsulate the latest advances and essential aspects of the pathogenesis of metabolic liver disease-associated HCC, including alcoholic liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and inherited metabolic liver diseases.

Impact of Alcohol on Inflammation, Immunity, Infections, and Extracellular Vesicles in Pathogenesis

Alcohol consumption is a widespread social activity with a complex and multifaceted impact on human health. Although moderate alcohol consumption has been associated with certain potential health benefits, excessive or chronic alcohol use can disrupt the body's immune balance, promote inflammation, and increase susceptibility to infections. The deleterious effects associated with alcohol toxicity include the loss of cell integrity. When cells lose their integrity, they also lose the capacity to communicate with other systems. One of the systems disturbed by alcohol toxicity is extracellular vesicle (EV)-mediated communication. EVs are critical mediators of cell-to-cell communication. They play a significant role in alcohol-induced pathogenesis, facilitating communication and molecular exchange between cells, thereby potentially contributing to alcohol-related health issues. Investigating their involvement in this context is fundamental to resolving the intricate mechanisms behind the health consequences of alcohol use and may pave the way for innovative approaches for mitigating the adverse effects of alcohol on immune health. Understanding the role of EVs in the context of alcohol-induced pathogenesis is essential for comprehending the mechanisms behind alcohol-related health issues.

Stemness markers in hepatocellular carcinoma of Eastern vs. Western population: Etiology matters?

Hepatocellular carcinoma (HCC) is one of the most common cancers with a high mortality rate. HCC development is associated with its underlying etiologies, mostly caused by infection of chronic hepatitis B virus (HBV) and hepatitis C virus (HCV), alcohol, non-alcoholic fatty liver disease, and exposure to aflatoxins. These variables, together with human genetic susceptibility, contribute to HCC molecular heterogeneity, including at the cellular level. HCC initiation, tumor recurrence, and drug resistance rates have been attributed to the presence of liver cancer stem cells (CSC). This review summarizes available data regarding whether various HCC etiologies may be associated to the appearance of CSC biomarkers. It also described the genetic variations of tumoral tissues obtained from Western and Eastern populations, in particular to the oncogenic effect of HBV in the human genome.

Alcohol-Associated Liver Disease: Evolving Concepts and Treatments

Alcohol is a prominent cause of liver disease worldwide with higher prevalence in developed nations. The spectrum of alcohol-associated liver disease (ALD) encompasses a diverse range of clinical entities, from asymptomatic isolated steatosis to decompensated cirrhosis, and in some cases, acute or chronic liver failure. Consequently, it is important for healthcare practitioners to maintain awareness and systematically screen for ALD. The optimal evaluation and management of ALD necessitates a collaborative approach, incorporating a multidisciplinary team and accounting for concurrent medical conditions. A repertoire of therapeutic interventions exists to support patients in achieving alcohol cessation and sustaining remission, with complete abstinence being the ultimate objective. This review explores the existing therapeutic options for ALD acknowledging geographical discrepancies in accessibility. Recent innovations, including the inclusion of alcohol consumption biomarkers into clinical protocols and the expansion of liver transplantation eligibility to encompass severe alcohol-associated hepatitis, are explored.

The role and mechanism of action of microRNA-122 in cancer: Focusing on the liver

microRNA-122 (miR-122) is a highly conserved microRNA that is predominantly expressed in the liver and plays a critical role in the regulation of liver metabolism. Recent studies have shown that miR-122 is involved in the pathogenesis of various types of cancer, particularly liver cancer. In this sense, The current findings highlighted the potential role of miR-122 in regulating many vital processes in cancer pathophysiology, including apoptosis, signaling pathway, cell metabolism, immune system response, migration, and invasion. These results imply that miR-122, which has been extensively studied for its biological functions and potential therapeutic applications, acts as a tumor suppressor or oncogene in cancer development. We first provide an overview and summary of the physiological function and mode of action of miR-122 in liver cancer. We will examine the various signaling pathways and molecular mechanisms through which miR-122 exerts its effects on cancer cells, including the regulation of oncogenic and tumor suppressor genes, the modulation of cell proliferation and apoptosis, and the regulation of metastasis. Most importantly, we will also discuss the potential diagnostic and therapeutic applications of miR-122 in cancer, including the development of miRNA-based biomarkers for cancer diagnosis and prognosis, and the potential use of miR-122 as a therapeutic target for cancer treatment.

β-CATENIN stabilizes HIF2 through lncRNA and inhibits intravenous immunoglobulin immunotherapy

Introduction

Tumor-initiating cells (TICs) are rare, stem-like, and highly malignant. Although intravenous hepatitis B and C immunoglobulins have been used for HBV and HCV neutralization in patients, their tumor-inhibitory effects have not yet been examined. Hepatitis B immunoglobulin (HBIG) therapy is employed to reduce hepatocellular carcinoma (HCC) recurrence in patients after living donor liver transplantations (LDLT).

Hypothesis

We hypothesized that patient-derived intravenous immunoglobulin (IVIG) binding to HCC associated TICs will reduce self-renewal and cell viability driven by β-CATENIN-downstream pathways. β-CATENIN activity protected TICs from IVIG effects.

Methods

The effects of HBIG and HCIG binding to TICs were evaluated for cell viability and self-renewal.

Results

Inhibition of β-CATENIN pathway(s) augmented TIC susceptibility to HBIG- and HCIG-immunotherapy. HBV X protein (HBx) upregulates both β-CATENIN and NANOG expression. The co-expression of constitutively active β-CATENIN with NANOG promotes self-renewal ability and tumor-initiating ability of hepatoblasts. HBIG bound to HBV+ cells led to growth inhibition in a TIC subset that expressed hepatitis B surface antigen. The HBx protein transformed cells through β-CATENIN-inducible lncRNAs EGLN3-AS1 and lnc-β-CatM. Co-expression of constitutively active β-CATENIN with NANOG promoted self-renewal ability of TICs through EGLN3 induction. β-CATENIN-induced lncRNAs stabilized HIF2 to maintain self-renewal of TICs. Targeting of EGLN3-AS1 resulted in destabilization of EZH2-dependent β-CATENIN activity and synergized cell-killing of TICs by HBIG or HCIG immunotherapy.

Discussion

Taken together, WNT and stemness pathways induced HIF2 of TICs via cooperating lncRNAs resulting in resistance to cancer immunotherapy. Therefore, therapeutic use of IVIG may suppress tumor recurrence through inhibition of TICs.

LIN28 and histone H3K4 methylase induce TLR4 to generate tumor-initiating stem-like cells

Chemoresistance and plasticity of tumor-initiating stem-like cells (TICs) promote tumor recurrence and metastasis. The gut-originating endotoxin-TLR4-NANOG oncogenic axis is responsible for the genesis of TICs. This study investigated mechanisms as to how TICs arise through transcriptional, epigenetic, and post-transcriptional activation of oncogenic TLR4 pathways. Here, we expressed constitutively active TLR4 (caTLR4) in mice carrying pLAP-tTA or pAlb-tTA, under a tetracycline withdrawal-inducible system. Liver progenitor cell induction accelerated liver tumor development in caTLR4-expressing mice. Lentiviral shRNA library screening identified histone H3K4 methylase SETD7 as central to activation of TLR4. SETD7 combined with hypoxia induced TLR4 through HIF2 and NOTCH. LIN28 post-transcriptionally stabilized TLR4 mRNA via de-repression of let-7 microRNA. These results supported a LIN28-TLR4 pathway for the development of HCCs in a hypoxic microenvironment. These findings not only advance our understanding of molecular mechanisms responsible for TIC generation in HCC, but also represent new therapeutic targets for the treatment of HCC.

HCV and tumor-initiating stem-like cells

Neoplasms contain tumor-initiating stem-like cells (TICs) that are characterized by increased drug resistance. The incidence of many cancer types have trended downward except for few cancer types, including hepatocellular carcinoma (HCC). Therefore mechanism of HCC development and therapy resistance needs to be understood. These multiple hits by hepatitis C virus (HCV) eventually promotes transformation and TIC genesis, leading to HCC development. This review article describes links between HCV-associated HCC and TICs. This review discusses 1) how HCV promotes genesis of TICs and HCC development; 2) how this process avails itself as a novel therapeutic target for HCC treatment; and 3) ten hall marks of TIC oncogenesis and HCC development as targets for novel therapeutic modalities.

Chronic Alcohol Exposure Promotes Cancer Stemness and Glycolysis in Oral/Oropharyngeal Squamous Cell Carcinoma Cell Lines by Activating NFAT Signaling

Alcohol consumption is associated with an increased risk of several cancers, including oral/oropharyngeal squamous cell carcinoma (OSCC). Alcohol also enhances the progression and aggressiveness of existing cancers; however, its underlying molecular mechanism remains elusive. Especially, the local carcinogenic effects of alcohol on OSCC in closest contact with ingestion of alcohol are poorly understood. We demonstrated that chronic ethanol exposure to OSCC increased cancer stem cell (CSC) populations and their stemness features, including self-renewal capacity, expression of stem cell markers, ALDH activity, and migration ability. The ethanol exposure also led to a significant increase in aerobic glycolysis. Moreover, increased aerobic glycolytic activity was required to support the stemness phenotype of ethanol-exposed OSCC, suggesting a molecular coupling between cancer stemness and metabolic reprogramming. We further demonstrated that chronic ethanol exposure activated NFAT (nuclear factor of activated T cells) signaling in OSCC. Functional studies revealed that pharmacological and genetic inhibition of NFAT suppressed CSC phenotype and aerobic glycolysis in ethanol-exposed OSCC. Collectively, chronic ethanol exposure promotes cancer stemness and aerobic glycolysis via activation of NFAT signaling. Our study provides a novel insight into the roles of cancer stemness and metabolic reprogramming in the molecular mechanism of alcohol-mediated carcinogenesis.

Microbiome-Based Metabolic Therapeutic Approaches in Alcoholic Liver Disease

Alcohol consumption is a global healthcare problem. Chronic alcohol consumption generates a wide spectrum of hepatic lesions, the most characteristic of which are steatosis, hepatitis, fibrosis, and cirrhosis. Alcoholic liver diseases (ALD) refer to liver damage and metabolomic changes caused by excessive alcohol intake. ALD present several clinical stages of severity found in liver metabolisms. With increased alcohol consumption, the gut microbiome promotes a leaky gut, metabolic dysfunction, oxidative stress, liver inflammation, and hepatocellular injury. Much attention has focused on ALD, such as alcoholic fatty liver (AFL), alcoholic steatohepatitis (ASH), alcoholic cirrhosis (AC), hepatocellular carcinoma (HCC), a partnership that reflects the metabolomic significance. Here, we report on the global function of inflammation, inhibition, oxidative stress, and reactive oxygen species (ROS) mechanisms in the liver biology framework. In this tutorial review, we hypothetically revisit therapeutic gut microbiota-derived alcoholic oxidative stress, liver inflammation, inflammatory cytokines, and metabolic regulation. We summarize the perspective of microbial therapy of genes, gut microbes, and metabolic role in ALD. The end stage is liver transplantation or death. This review may inspire a summary of the gut microbial genes, critical inflammatory molecules, oxidative stress, and metabolic routes, which will offer future promising therapeutic compounds in ALD.

Molecular Targets and Signaling Pathways of microRNA-122 in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading global causes of cancer mortality. MicroRNAs (miRNAs) are small interfering RNAs that alleviate the levels of protein expression by suppressing translation, inducing mRNA cleavage, and promoting mRNA degradation. miR-122 is the most abundant miRNA in the liver and is responsible for several liver-specific functions, including metabolism, cellular growth and differentiation, and hepatitis virus replication. Recent studies have shown that aberrant regulation of miR-122 is a key factor contributing to the development of HCC. In this review, the signaling pathways and the molecular targets of miR-122 involved in the progression of HCC have been summarized, and the importance of miR-122 in therapy has been discussed.

The role of immune cells in the liver tumor microenvironment: an involvement of gut microbiota-derived factors

More than 500 species of microbiota reside in the human intestine and coexist with humans, their host. Gut microbial metabolites and components are absorbed from the intestine and influence cells in the liver, including hepatocytes and stromal cells, such as liver sinusoidal endothelial cells, hepatic stellate cells, Kupffer cells, natural killer (NK) cells, NK T cells, and other immune cells. This gut-originated axis to the liver is called the "gut-liver axis", which underscores the importance of the link between the gut and the liver. In this review, we discuss the gut microbial components and metabolites that affect cells in the liver, particularly in association with immune cells, and the related responses. We also highlight the mechanisms underlying gut microbiota-mediated liver carcinogenesis and discuss cancer prevention, including the recently clarified modulation of immune checkpoint inhibitor efficacy by the gut microbiota.

Gut-derived lipopolysaccharide promotes alcoholic hepatosteatosis and subsequent hepatocellular carcinoma by stimulating neutrophil extracellular traps through TLR4

Background/Aims

Binge drinking leads to many disorders, including alcoholic hepatosteatosis, which is characterized by intrahepatic neutrophil infiltration and increases the risk of hepatocellular carcinoma (HCC). Molecular mechanisms may involve the migration of bacterial metabolites from the gut to the liver and the activation of neutrophil extracellular traps (NETs).

Methods

Serum samples from both binge drinking and alcohol-avoiding patients were analyzed. Mouse models of chronic plus binge alcohol-induced hepatosteatosis and HCC models were used.

Results

A marker of NETs formation, lipopolysaccharide (LPS), was significantly higher in alcoholic hepatosteatosis and HCC patients and mice than in controls. Intrahepatic inflammation markers and HCC-related cytokines were decreased in mice with reduced NET formation due to neutrophil elastase (NE) deletion, and liver-related symptoms of alcohol were also alleviated in NE knockout mice. Removal of intestinal bacteria with antibiotics led to decreases in markers of NETs formation and inflammatory cytokines upon chronic alcohol consumption, and development of alcoholic hepatosteatosis and HCC was also attenuated. These functions were restored upon supplementation with the bacterial product LPS. When mice lacking toll-like receptor 4 (TLR4) received chronic alcohol feeding, intrahepatic markers of NETs formation decreased, and hepatosteatosis and HCC were alleviated.

Conclusions

Formation of NETs following LPS stimulation of TLR4 upon chronic alcohol use leads to increased alcoholic steatosis and subsequent HCC.

A review of alcohol-pathogen interactions: New insights into combined disease pathomechanisms

Progression of chronic infections to end-stage diseases and poor treatment results are frequently associated with alcohol abuse. Alcohol metabolism suppresses innate and adaptive immunity leading to increased viral load and its spread. In case of hepatotropic infections, viruses accelerate alcohol-induced hepatitis and liver fibrosis, thereby promoting end-stage outcomes, including cirrhosis and hepatocellular carcinoma (HCC). In this review, we concentrate on several unexplored aspects of these phenomena, which illustrate the combined effects of viral/bacterial infections and alcohol in disease development. We review alcohol-induced alterations implicated in immunometabolism as a central mechanism impacting metabolic homeostasis and viral pathogenesis in Simian immunodeficiency virus/human immunodeficiency virus infection. Furthermore, in hepatocytes, both HIV infection and alcohol activate oxidative stress to cause lysosomal dysfunction and leakage and apoptotic cell death, thereby increasing hepatotoxicity. In addition, we discuss the mechanisms of hepatocellular carcinoma and tumor signaling in hepatitis C virus infection. Finally, we analyze studies that review and describe the immune derangements in hepatotropic viral infections focusing on the development of novel targets and strategies to restore effective immunocompetency in alcohol-associated liver disease. In conclusion, alcohol exacerbates the pathogenesis of viral infections, contributing to a chronic course and poor outcomes, but the mechanisms behind these events are virus specific and depend on virus-alcohol interactions, which differ among the various infections.

Alcohol Metabolism Enriches Squamous Cell Carcinoma Cancer Stem Cells That Survive Oxidative Stress via Autophagy

BACKGROUND

Alcohol (ethanol) consumption is a major risk factor for head and neck and esophageal squamous cell carcinomas (SCCs). However, how ethanol (EtOH) affects SCC homeostasis is incompletely understood.

METHODS

We utilized three-dimensional (3D) organoids and xenograft tumor transplantation models to investigate how EtOH exposure influences intratumoral SCC cell populations including putative cancer stem cells defined by high CD44 expression (CD44H cells).

RESULTS

Using 3D organoids generated from SCC cell lines, patient-derived xenograft tumors, and patient biopsies, we found that EtOH is metabolized via alcohol dehydrogenases to induce oxidative stress associated with mitochondrial superoxide generation and mitochondrial depolarization, resulting in apoptosis of the majority of SCC cells within organoids. However, CD44H cells underwent autophagy to negate EtOH-induced mitochondrial dysfunction and apoptosis and were subsequently enriched in organoids and xenograft tumors when exposed to EtOH. Importantly, inhibition of autophagy increased EtOH-mediated apoptosis and reduced CD44H cell enrichment, xenograft tumor growth, and organoid formation rate.

CONCLUSIONS

This study provides mechanistic insights into how EtOH may influence SCC cells and establishes autophagy as a potential therapeutic target for the treatment of EtOH-associated SCC.

Regulators of liver cancer stem cells

Hepatocellular carcinoma (HCC) is a leading cause of cancer deaths. It is often detected at a stage when there are few therapeutic options. Liver cancer stem cells (LCSCs) are highly tumorigenic and resistant to chemotherapy and radiation therapy. Their presence in HCC is a major reason why HCC is difficult to treat. The development of LCSCs is regulated by a variety of factors. This review summarizes recent advances on the factors that regulate the development of LCSCs. Due to the importance of LCSCs in the development of HCC, a better understanding of how LCSCs are regulated will help to improve the treatments for HCC patients.

The Gut Microbiota-Derived Immune Response in Chronic Liver Disease

In chronic liver disease, the causative factor is important; however, recently, the intestinal microbiome has been associated with the progression of chronic liver disease and the occurrence of side effects. The immune system is affected by the metabolites of the microbiome, and diet is the primary regulator of the microbiota composition and function in the gut–liver axis. These metabolites can be used as therapeutic material, and postbiotics, in the future, can increase or decrease human immunity by modulating inflammation and immune reactions. Therefore, the excessive intake of nutrients and the lack of nutrition have important effects on immunity and inflammation. Evidence has been published indicating that microbiome-induced chronic inflammation and the consequent immune dysregulation affect the development of chronic liver disease. In this research paper, we discuss the overall trend of microbiome-derived substances related to immunity and the future research directions.

Elevation of Plasminogen Activator Inhibitor-1 promotes differentiation of Cancer Stem-like Cell state by Hepatitis C Virus infection

Plasminogen activator inhibitor-1 (PAI-1) is a critical factor that regulates protein synthesis and degradation. The increased PAI-1 levels are detectable in the serum of patients with chronic hepatitis C virus (HCV) liver disease. The differentiation state and motility of HCV-induced cancer stem-like cells (CSC) play a major role in severe liver disease progression. However, the role of PAI-1 in the pathological process of chronic liver diseases remains unknown. In this study, we determined how PAI-1 affects the differentiation of CSC state in hepatocytes upon HCV infection. We found that HCV infection induced the expression of PAI-1 while decreasing miR-30c expression in Huh7.5.1 cells. Similar results were obtained from isolated hepatocytes from humanized liver mice after HCV infection. Moreover, decreased miR-30c expression in HCV-infected hepatocytes was associated with the increased levels of PAI-1 mRNA and protein. Notably, the increased PAI-1 levels resulted in the activation of Protein Kinase B/AKT, a major mediator of cell proliferation, in HCV-infected hepatocytes along with the increased expression of CSC markers such as Human Differentiated Protein (CD) 133, Epithelial cell adhesion molecule (EpCAM), Octamer 4 (Oct4), Nanog, Cyclin D1, and MYC. Moreover, blockade of PAI-1 activity by miR-30c mimic and anti-PAI-1 mAb abrogated the AKT activation with decreased expression of CSC markers. Our findings suggest that HCV infection induces the CSC state via PAI-1-mediated AKT activation in hepatocytes. It implicates that the manipulation of PAI-1 activity could provide potential therapeutics to prevent the development of HCV-associated chronic liver diseases.IMPORTANCEThe progression of chronic liver disease by HCV infection is considered a major risk factor for hepatocellular carcinoma (HCC), one of the major causes of death from cancer. Recent studies have demonstrated that increased CSC properties in HCV-infected hepatocytes are associated with the progression of HCC. Since proteins and miRNAs production by HCV-infected hepatocytes can play various roles in physiological processes, investigating these factors can potentially lead to new therapeutic targets. However, the mechanism of HCV associated progression of hepatocytes to CSC remains unclear. Here we identify the roles of PAI-1 and miR-30c in the progression of CSC during HCV infection in hepatocytes. Our data shows that increased secretion of PAI-1 following HCV infection promotes this CSC state and activation of AKT. We report that the inhibition of PAI-1 by miR-30c mimic reduces HCV associated CSC properties in hepatocytes. Taken together, targeting this interaction of secreted PAI-1 and miR-30c in HCV-infected hepatocytes may provide a potential therapeutic intervention against the progression to chronic liver diseases and HCC.

Examining the gut-liver axis in liver cancer using organoid models

The World Health Organization predicts that by 2030 liver cancer will cause 1 million deaths annually, thus becoming the third most lethal cancer worldwide. Hepatocellular carcinoma and cholangiocarcinoma are the two major primary cancer subtypes involving the liver. Both are often diagnosed late, and hence response to treatment and survival are poor. It is therefore of utmost importance to understand the mechanisms by which liver cancers initiate and progress. The causes of primary liver cancer are diverse, resulting primarily from obesity, chronic alcohol abuse or viral hepatitis. Importantly, both alcohol and high fat diet can promote intestinal permeability, enabling microbial translocation from the gut into the liver. As a result, these microbial antigens and metabolites exacerbate hepatic inflammation and fibrosis, increasing the risk of primary liver cancer. Organoids are primary, three-dimensional, stem cell derived liver models that can recapitulate many of the disease phenotypes observed in vivo. This review aims to summarize the advantages of organoid culture to examine the gut-liver axis with respect to cancer initiation and progression. In particular, the use of gut and liver organoid mono- and co-cultures together and with immune cell populations to best recapitulate disease mechanisms and develop therapeutic interventions.

Immunotherapy for targeting cancer stem cells in hepatocellular carcinoma

The rapid development and remarkable success of checkpoint inhibitors have provided significant breakthroughs in cancer treatment, including hepatocellular carcinoma (HCC). However, only 15-20% of HCC patients can benefit from checkpoint inhibitors. Cancer stem cells (CSCs) are responsible for recurrence, metastasis, and local and systemic therapy resistance in HCC. Accumulating evidence has suggested that HCC CSCs can create an immunosuppressive microenvironment through certain intrinsic and extrinsic mechanisms, resulting in immune evasion. Intrinsic evasion mechanisms mainly include activation of immune-related CSC signaling pathways, low-level expression of antigen presenting molecules, and high-level expression of immunosuppressive molecules. External evasion mechanisms are mainly related to HBV/HCV infection, alcoholic/nonalcoholic steatohepatitis, hypoxia stimulation, abnormal angiogenesis, and crosstalk between CSCs and immune cells. A better understanding of the complex mechanisms of CSCs involved in immune evasion will contribute to therapies for HCC. Here we will outline the detailed mechanisms of immune evasion for CSCs, and provide an overview of the current immunotherapies targeting CSCs in HCC.

Plasminogen Activator Inhibitor-1 and Oncogenesis in the Liver Disease

Hepatocellular carcinoma (HCC) is a significant cause of cancer mortality worldwide. Chronic hepatic inflammation and fibrosis play a critical role in the development of HCC. Liver fibrosis develops as a result of response to injury such that a persistent and excessive wound healing response induces extracellular matrix (ECM) deposition leading to HCC. PAI-1 is a fibrinolysis inhibitor involved in regulating protein degradation and homeostasis while assisting wound healing. PAI-1 presents increased levels in various diseases such as fibrosis, cancer, obesity and metabolic syndrome. Moreover, PAI-1 has been extensively studied for developing potential therapies against fibrosis. In the present review, we summarize how PAI-1 affects oncogenesis during liver disease progression based on the recently published literatures. Although there are controversies regarding the role of PAI-1 and approaches to treatment, this review suggests that proper manipulation of PAI-1 activity could provide a novel therapeutic option on the development of chronic liver disease via modulation of cancer stem-like cells (CSCs) differentiation.

Fate and functional roles of Prominin 1+ cells in liver injury and cancer

Prominin 1 (PROM1) is one of a few clinically relevant progenitor markers in human alcoholic hepatitis (AH) and hepatocellular carcinoma (HCC), and mouse liver tumor initiating stem cell-like cells (TICs). However, the origin, fate and functions of PROM1⁺ cells in AH and HCC are unknown. Here we show by genetic lineage tracing that PROM1⁺ cells are derived in part from hepatocytes in AH and become tumor cells in mice with diethyl nitrosamine (DEN)-initiated, Western alcohol diet-promoted liver tumorigenesis. Our RNA sequencing analysis of mouse PROM1⁺ cells, reveals transcriptomic landscapes indicative of their identities as ductular reaction progenitors (DRPs) and TICs. Indeed, single-cell RNA sequencing reveals two subpopulations of Prom1⁺ Afp^– DRPs and Prom1⁺ Afp⁺ TICs in the DEN-WAD model. Integrated bioinformatic analysis identifies Discodin Domain Receptor 1 (DDR1) as a uniquely upregulated and patient-relevant gene in PROM1⁺ cells in AH and HCC. Translational relevance of DDR1 is supported by its marked elevation in HCC which is inversely associated with patient survival. Further, knockdown of Ddr1 suppresses the growth of TICs and TIC-derived tumor growth in mice. These results suggest the importance of PROM1⁺ cells in the evolution of liver cancer and DDR1 as a potential driver of this process.

Gut-Pancreas-Liver Axis as a Target for Treatment of NAFLD/NASH

Non-alcoholic fatty liver disease (NAFLD) represents the most common form of chronic liver disease worldwide. Due to its association with obesity and diabetes and the fall in hepatitis C virus morbidity, cirrhosis in NAFLD is becoming the most frequent indication to liver transplantation, but the pathogenetic mechanisms are still not completely understood. The so-called gut-liver axis has gained enormous interest when data showed that its alteration can lead to NAFLD development and might favor the occurrence of non-alcoholic steatohepatitis (NASH). Moreover, several therapeutic approaches targeting the gut-pancreas-liver axis, e.g., incretins, showed promising results in NASH treatment. In this review, we describe the role of incretin hormones in NAFLD/NASH pathogenesis and treatment and how metagenomic/metabolomic alterations in the gut microbiota can lead to NASH in the presence of gut barrier modifications favoring the passage of bacteria or bacterial products in the portal circulation, i.e., bacterial translocation.

Mitogen- and Stress-Activated Protein Kinase 1 Mediates Alcohol-Upregulated Transcription of Brf1 and tRNA Genes to Cause Phenotypic Alteration

Upregulation of Brf1 (TFIIB-related factor 1) and Pol III gene (RNA polymerase III-dependent gene, such as tRNAs and 5S rRNA) activities is associated with cell transformation and tumor development. Alcohol intake causes liver injury, such as steatosis, inflammation, fibrosis, and cirrhosis, which enhances the risk of HCC development. However, the mechanism of alcohol-promoted HCC remains to be explored. We have designed the complementary research system, which is composed of cell lines, an animal model, human samples, and experiments in vivo and in vitro, to carry out this project by using molecular biological, biochemical, and cellular biological approaches. It is a unique system to explore the mechanism of alcohol-associated HCC. Our results indicate that alcohol upregulates Brf1 and Pol III gene (tRNAs and 5S rRNA) transcription in primary mouse hepatocytes, immortalized mouse hepatocyte-AML-12 cells, and engineered human HepG2-ADH cells. Alcohol activates MSK1 to upregulate expression of Brf1 and Pol III genes, while inhibiting MSK1 reduces transcription of Brf1 and Pol III genes in alcohol-treated cells. The inhibitor of MSK1, SB-747651A, decreases the rates of cell proliferation and colony formation. Alcohol feeding promotes liver tumor development of the mouse. These results, for the first time, show the identification of the alcohol-response promoter fragment of the Pol III gene key transcription factor, Brf1. Our studies demonstrate that Brf1 expression is elevated in HCC tumor tissues of mice and humans. Alcohol increases cellular levels of Brf1, resulting in enhancement of Pol III gene transcription in hepatocytes through MSK1. Our mechanism analysis has demonstrated that alcohol-caused high-response fragment of the Brf1 promoter is at p-382/+109bp. The MSK1 inhibitor SB-747651A is an effective reagent to repress alcohol-induced cell proliferation and colony formation, which is a potential pharmaceutical agent. Developing this inhibitor as a therapeutic approach will benefit alcohol-associated HCC patients.

p53 destabilizing protein skews asymmetric division and enhances NOTCH activation to direct self-renewal of TICs

Tumor-initiating stem-like cells (TICs) are defective in maintaining asymmetric cell division and responsible for tumor recurrence. Cell-fate-determinant molecule NUMB-interacting protein (TBC1D15) is overexpressed and contributes to p53 degradation in TICs. Here we identify TBC1D15-mediated oncogenic mechanisms and tested the tumorigenic roles of TBC1D15 in vivo. We examined hepatocellular carcinoma (HCC) development in alcohol Western diet-fed hepatitis C virus NS5A Tg mice with hepatocyte-specific TBC1D15 deficiency or expression of non-phosphorylatable NUMB mutations. Liver-specific TBC1D15 deficiency or non-p-NUMB expression reduced TIC numbers and HCC development. TBC1D15–NuMA1 association impaired asymmetric division machinery by hijacking NuMA from LGN binding, thereby favoring TIC self-renewal. TBC1D15–NOTCH1 interaction activated and stabilized NOTCH1 which upregulated transcription of NANOG essential for TIC expansion. TBC1D15 activated three novel oncogenic pathways to promote self-renewal, p53 loss, and Nanog transcription in TICs. Thus, this central regulator could serve as a potential therapeutic target for treatment of HCC.

Normal stem cells are maintained by asymmetric cell division, but this process is dysregulated in tumour initiating stem-like cells (TICs). Here, the authors show that TBC1D15 impairs the asymmetric division machinery and activates NOTCH pathway for TIC self-renewal and expansion to promote liver tumorigenesis.

Hepatocellular Carcinoma Mechanisms Associated with Chronic HCV Infection and the Impact of Direct-Acting Antiviral Treatment

Hepatitis C virus (HCV) infection is the major risk factor for liver cirrhosis and hepatocellular carcinoma (HCC). The mechanisms of HCC initiation, growth, and metastasis appear to be highly complex due to the decade-long interactions between the virus, immune system, and overlapping bystander effects of host metabolic liver disease. The lack of a readily accessible animal model system for HCV is a significant obstacle to understand the mechanisms of viral carcinogenesis. Traditionally, the primary prevention strategy of HCC has been to eliminate infection by antiviral therapy. The success of virus elimination by antiviral treatment is determined by the SVR when the HCV is no longer detectable in serum. Interferon-alpha (IFN-α) and its analogs, pegylated IFN-α (PEG-IFN-α) alone with ribavirin (RBV), have been the primary antiviral treatment of HCV for many years with a low cure rate. The cloning and sequencing of HCV have allowed the development of cell culture models, which accelerated antiviral drug discovery. It resulted in the selection of highly effective direct-acting antiviral (DAA)-based combination therapy that now offers incredible success in curing HCV infection in more than 95% of all patients, including those with cirrhosis. However, several emerging recent publications claim that patients who have liver cirrhosis at the time of DAAs treatment face the risk of HCC occurrence and recurrence after viral cure. This remains a substantial challenge while addressing the long-term benefit of antiviral medicine. The host-related mechanisms that drive the risk of HCC in the absence of the virus are unknown. This review describes the multifaceted mechanisms that create a tumorigenic environment during chronic HCV infection. In addition to the potential oncogenic programming that drives HCC after viral clearance by DAAs, the current status of a biomarker development for early prediction of cirrhosis regression and HCC detection post viral treatment is discussed. Since DAAs treatment does not provide full protection against reinfection or viral transmission to other individuals, the recent studies for a vaccine development are also reviewed.

Cell fate, metabolic reprogramming and lncRNA of tumor-initiating stem-like cells induced by alcohol

Alcoholism synergizes the development of the hepatocellular carcinoma (HCC) in patients infected with hepatitis B or C virus (HBV or HCV). Tumor-initiating stem-like cells (TICs) are refractory to therapy and have expression of stemness transcription factors. Leaky-gut-derived endotoxin stimulates TLR4-NANOG pathway that skews asymmetric cell division and that metabolically reprograms hepatocytes/liver progenitor cells, leading to self-renewal. TICs isolated from mouse HCC models or human HCCs are tumorigenic and have p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncofetal protein TBC1D15. Furthermore, dysregulation of lncRNA promotes genesis of TICs, leading to HCC development. This review describes roles of cell fate decision, metabolic reprogramming and lncRNA for TIC genesis and liver oncogenesis. This project was supported by NIH grants 1R01AA018857-01, 5R21AA025470, P50AA11999 (Animal Core, Morphology Core, and Pilot Project Program), R24AA012885 (Non-Parenchymal Liver Cell Core) and pilot project funding (5P30DK048522-13).

Crosstalk between NLRP12 and JNK during Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC), a leading cause of cancer-related death, is initiated and promoted by chronic inflammation. Inflammatory mediators are transcriptionally regulated by several inflammatory signaling pathways, including nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK). cJun N-terminal kinase (JNK), a member of the MAPK family, plays a central role in HCC pathogenesis. Pathogen-associated molecular patterns (PAMPs) activate JNK and other MAPK upon recognition by toll-like receptors (TLRs). Apart from TLRs, PAMPs are sensed by several other pattern recognition receptors, including cytosolic NOD-like receptors (NLRs). In a recent study, we demonstrated that the NLR member NLRP12 plays a critical role in suppressing HCC via negative regulation of the JNK pathway. This article briefly reviews the crosstalk between NLRP12 and JNK that occurs during HCC.

Silencing transcription factor FOXM1 represses proliferation, migration, and invasion while inducing apoptosis of liver cancer stem cells by regulating the expression of ALDH2

OBJECTIVE

This study is performed to explore the role of transcription factor FOXM1 in promoting the self-renewal and proliferation of liver cancer stem cells (LCSCs) by regulating the expression of acetaldehyde dehydrogenase-2 (ALDH2).

METHODS

CD133⁺ CD24⁺ LCSCs were sorted and identified. A series of experiments were carried out to determine the proliferation, colony formation rate, migration, invasion, and apoptosis of LCSCs after interfering with FOXM1. Proliferation-, epithelial-mesenchymal transition (EMT)-, apoptosis-, and stemness-related factors were then detected by western blot analysis. Tumor xenograft in nude mice was used to figure out the role of FOXM1 in tumorigenesis in vivo by regulating ALDH2 expression. Luciferase activity assay was conducted to determine whether FOXM1 could target ALDH2 promoter region and thereby affecting ALDH2 expression.

RESULTS

The sorted CD133⁺ CD24⁺ Huh-7 cells had the characteristic of stem cells. FOXM1 was highly expressed in CD133⁺ CD24⁺ Huh-7 cells. Silencing FOXM1 inhibited the proliferation and colony formation of LCSCs and decreased the expression of proliferating cell nuclear antigen and Ki-67 protein; inhibited the migration, invasion, and EMT of LCSCs while promoting the apoptosis of LCSCs, as well as promoted the expression of Bax and cleaved-caspase-3, and inhibited the expression of Bcl-2. Silencing FOXM1 inhibited the expression of Nanog, Oct4, and Sox2 in LCSCs by decreasing the expression of ALDH2. in vivo experiment, silencing FOXM1 suppressed tumorigenesis of LCSCs by decreasing the expression of ALDH2.

CONCLUSION

Our study provides evidence that silencing FOXM1 inhibits stemness of LCSCs by decreasing the expression of ALDH2, and represses the proliferation, migration, invasion, and tumorigenesis while inducing the apoptosis of LCSCs.

Dedifferentiation process driven by radiotherapy-induced HMGB1/TLR2/YAP/HIF-1α signaling enhances pancreatic cancer stemness

Differentiated cancer cells reacquiring stem cell traits following radiotherapy may enrich cancer stem cells and accelerate tumor recurrence and metastasis. We are interested in the mechanistic role of dying cells-derived HMGB1 in CD133^- pancreatic cancer cells dedifferentiation following radiotherapy. We firstly confirmed that X-ray irradiation induced differentiation of CD133^- pancreatic cancer cells, from either sorted from patient samples or established cell lines, into cancer stem-like cells (iCSCs). Using an in vitro coculture model, X-ray irradiation induced dying cells to release HMGB1, which further promoted CD133^- pancreatic cancer cells regaining stem cell traits, such as higher sphere forming ability and expressed higher level of stemness-related genes and proteins. Inhibiting the expression and activity of HMGB1 attenuated the dedifferentiation stimulating effect of irradiated, dying cells on C133^- pancreatic cancer cells in vitro and in PDX models. Mechanistically, HMGB1 binding with TLR2 receptor functions in a paracrine manner to affect CD133^- pancreatic cancer cells dedifferentiation via activating Hippo-YAP pathway and HIF-1α expression in oxygen independent manner in vitro and in vivo. We conclude that X-ray irradiation induces CD133^- pancreatic cancer cell dedifferentiation into a CSC phenotype, and inhibiting HMGB1 may be a strategy to prevent CSC enrichment and further pancreatic carcinoma relapse.

The contribution of miR-122 to the innate immunity by regulating toll-like receptor 4 in hepatoma cells

BACKGROUND

Hepatocellular carcinoma (HCC) is a kind of malignancies to impact human health. It has been reported that aberrant toll-like receptor (TLR) signaling may contribute to the development and progression of HCC, especially TLR4. MiR-122, which extensively involved in hepatitis virus infection and the apoptosis of hepatoma cells, might be decreased in HCC patients livers. The hypothesis of this study was whether miR-122 plays a role in inflammatory pathways through regulating TLR4 expression in hepatoma cells.

METHODS

The expression of miR-122 in the tissues of HCC patients compared to controls in TCGA datasets was analyzed. The relationship between miR-122 and TLR4 was detected in HCC cell lines by increasing/decreasing miR-122 expression. The target of miR-122 on TLR4 was confirmed by luciferase reporter assays. The proliferation of HCC cells and production of proinflammatory cytokines were measured with miR-122 upregulation and inhibition.

RESULTS

We found that the expression of miR-122 was decreased in HCC tissues and showed the diagnostic capacity for HCC in TCGA datasets. MiR-122 and TLR4 expression have negative correlation in normal liver cells and HCC cells. Upregulation of miR-122 significantly inhibited TLR4 expression in hepatoma cells, including in hepatoma cells with the induction of LPS, while knocking down miR-122 increased TLR4 expression. By screening potential miR-122 targets among TLR4, we found that there was a putative miR-122 target in TLR4 3'UTR. Mutations in the nt1603-nt1609 region of TLR4 3'UTR abandoned the impact of miR-122 on TLR4 expression. Over-expression/down-expression of miR-122 could influence the proliferation and the expression of natural immune factors.

CONCLUSIONS

MiR-122 might target TLR4 and regulate host innate immunity in hepatoma cells, which revealed a new molecular mechanism of miR-122 on the regulation of innate immunity.

NANOG-Dependent Metabolic Reprogramming and Symmetric Division in Tumor-Initiating Stem-like Cells

Alcohol abuse synergistically heightens the development of the third most deadliest cancer hepatocellular carcinoma (HCC) in patients infected with hepatitis C virus (HCV). Ectopically expressed TLR4 promotes liver tumorigenesis in alcohol-fed HCV Ns5a or Core transgenic mice. CD133+/CD49f + tumor-initiating stem cell-like cells (TICs) isolated from these models are tumorigenic have p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncoprotein TBC1D15. Nutrient deprivation reduces overexpressed TBC1D15 in TICs via autophagy-mediated degradation, suggesting a possible role of this oncoprotein in linking metabolic reprogramming and self-renewal.

Role of Gut Microbiota in Hepatocarcinogenesis

Hepatocellular carcinoma (HCC), one of the leading causes of death worldwide, has a causal nexus with liver injury, inflammation, and regeneration that accumulates over decades. Observations from recent studies have accounted for the involvement of the gut–liver axis in the pathophysiological mechanism responsible for HCC. The human intestine nurtures a diversified colony of microorganisms residing in the host ecosystem. The intestinal barrier is critical for conserving the normal physiology of the gut microbiome. Therefore, a rupture of this barrier or dysbiosis can cause the intestinal microbiome to serve as the main source of portal-vein endotoxins, such as lipopolysaccharide, in the progression of hepatic diseases. Indeed, increased bacterial translocation is a key sign of HCC. Considering the limited number of clinical studies on HCC with respect to the microbiome, we focus on clinical as well as animal studies involving the gut microbiota, with the current understandings of the mechanism by which the intestinal dysbiosis promotes hepatocarcinogenesis. Future research might offer mechanistic insights into the specific phyla targeting the leaky gut, as well as microbial dysbiosis, and their metabolites, which represent key pathways that drive HCC-promoting microbiome-mediated liver inflammation and fibrosis, thereby restoring the gut barrier function.

Homeobox Genes and Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer, and is the third leading cause of cancer-related deaths each year. It involves a multi-step progression and is strongly associated with chronic inflammation induced by the intake of environmental toxins and/or viral infections (i.e., hepatitis B and C viruses). Although several genetic dysregulations are considered to be involved in disease progression, the detailed regulatory mechanisms are not well defined. Homeobox genes that encode transcription factors with homeodomains control cell growth, differentiation, and morphogenesis in embryonic development. Recently, more aberrant expressions of Homeobox genes were found in a wide variety of human cancer, including HCC. In this review, we summarize the currently available evidence related to the role of Homeobox genes in the development of HCC. The objective is to determine the roles of this conserved transcription factor family and its potential use as a therapeutic target in future investigations.

NLRP12 suppresses hepatocellular carcinoma via downregulation of cJun N-terminal kinase activation in the hepatocyte

Hepatocellular carcinoma (HCC) is a deadly human cancer associated with chronic inflammation. The cytosolic pathogen sensor NLRP12 has emerged as a negative regulator of inflammation, but its role in HCC is unknown. Here we investigated the role of NLRP12 in HCC using mouse models of HCC induced by carcinogen diethylnitrosamine (DEN). Nlrp12^-/- mice were highly susceptible to DEN-induced HCC with increased inflammation, hepatocyte proliferation, and tumor burden. Consistently, Nlrp12^-/- tumors showed higher expression of proto-oncogenes cJun and cMyc and downregulation of tumor suppressor p21. Interestingly, antibiotics treatment dramatically diminished tumorigenesis in Nlrp12^-/- mouse livers. Signaling analyses demonstrated higher JNK activation in Nlrp12^-/- HCC and cultured hepatocytes during stimulation with microbial pattern molecules. JNK inhibition or NLRP12 overexpression reduced proliferative and inflammatory responses of Nlrp12^-/- hepatocytes. In summary, NLRP12 negatively regulates HCC pathogenesis via downregulation of JNK-dependent inflammation and proliferation of hepatocytes.

Inflammation and Liver Cancer: Molecular Mechanisms and Therapeutic Targets

Hepatocellular carcinoma (HCC) is associated with chronic inflammation and fibrosis arising from different etiologies, including hepatitis B and C and alcoholic and nonalcoholic fatty liver diseases. The inflammatory cytokines tumor necrosis factor-α and interleukin-6 and their downstream targets nuclear factor kappa B (NF-κB), c-Jun N-terminal kinase (JNK), and signal transducer and activator of transcription 3 drive inflammation-associated HCC. Further, while adaptive immunity promotes immune surveillance to eradicate early HCC, adaptive immune cells, such as CD8+ T cells, Th17 cells, and B cells, can also stimulate HCC development. Thus, the role of the hepatic immune system in HCC development is a highly complex topic. This review highlights the role of cytokine signals, NF-κB, JNK, innate and adaptive immunity, and hepatic stellate cells in HCC and discusses whether these pathways could be therapeutic targets. The authors will also discuss cholangiocarcinoma and liver metastasis because biliary inflammation and tumor-associated stroma are essential for cholangiocarcinoma development and because primary tumor-derived inflammatory mediators promote the formation of a "premetastasis niche" in the liver.

Mmu-miR-92a-2-5p targets TLR2 to relieve Schistosoma japonicum-induced liver fibrosis

According to conservative estimates, >230 million people are infected with schistosomiasis,which becomes one of the most common parasitic diseases. This study focuses on investigating in vivo and in vitro effects of mmu-miR-92a-2-5p in Schistosoma japonicum-induced liver fibrosis by targeting TLR2. Through bioinformatic analysis, the overexpression of TLR2 and the down-regulation of mmu-miR-92a-2-5p were revealed in the progression of S. japonicum-induced liver fibrosis. BALB/C mice were taken advantage to construct normal control and schistosomiasis liver fibrosis (SLF) model. The mice in model groups were transfected recombinant lentivirus (Lenti-mmu-miR-92a-2-5p or Lenti-NC) to alter the expression of mmu-miR-92a-2-5p in vivo. HE and Masson staining were employed to observe the pathological changes and collagenous fibrosis. QRT-PCR showed that mmu-miR-92a-2-5p was decreased while TLR2 was elevated in the infected groups. However, lenti-mmu-miR-92a-2-5p group could inhibit liver fibrosis. Then the effect of mmu-miR-92a-2-5p on S. japonicum-induced liver fibrosis including cell apoptosis rates, proliferation and proteins related to liver fibrosis was examined in NIH-3T3 mouse embryonic fibroblasts. Moreover, the association between mmu-miR-92a-2-5p and TLR2 was detected by dual-luciferase reporter gene assay and the expression of cytokines IL-4, IFN-γ and TNF-α in SLF model was detected by ELISA. Further, the knockout of TLR2 in C57BL/6J mice was used to confirm the association between mmu-miR-92a-2-5p and TLR2. Thus, these findings demonstrated that mmu-miR-92a-2-5p inhibited S. japonicum-induced liver fibrosis by targeting TLR2 in vitro and in vivo.

Alcoholic liver disease: A current molecular and clinical perspective

Heavy alcohol use is the cause of alcoholic liver disease (ALD). The ALD spectrum ranges from alcoholic steatosis to steatohepatitis, fibrosis, and cirrhosis. In Western countries, approximately 50% of cirrhosis-related deaths are due to alcohol use. While alcoholic cirrhosis is no longer considered a completely irreversible condition, no effective anti-fibrotic therapies are currently available. Another significant clinical aspect of ALD is alcoholic hepatitis (AH). AH is an acute inflammatory condition that is often comorbid with cirrhosis, and severe AH has a high mortality rate. Therapeutic options for ALD are limited. The established treatment for AH is corticosteroids, which improve short-term survival but do not affect long-term survival. Liver transplantation is a curative treatment option for alcoholic cirrhosis and AH, but patients must abstain from alcohol use for 6 months to qualify. Additional effective therapies are needed. The molecular mechanisms underlying ALD are complex and have not been fully elucidated. Various molecules, signaling pathways, and crosstalk between multiple hepatic and extrahepatic cells contribute to ALD progression. This review highlights established and emerging concepts in ALD clinicopathology, their underlying molecular mechanisms, and current and future ALD treatment options.

Baicalein Targets GTPase-Mediated Autophagy to Eliminate Liver Tumor-Initiating Stem Cell-Like Cells Resistant to mTORC1 Inhibition

Drug resistance is a major problem in the treatment of liver cancer. Mammalian Target of Rapamycin 1 (mTORC1) inhibitors have been tested for the treatment of liver cancer based on hyperactive mTOR in this malignancy. However, their clinical trials showed poor outcome, most likely due to their ability to upregulate CD133 and promote chemoresistance. The CD133+ tumor-initiating stem cell-like cells (TICs) isolated from mouse and human liver tumors are chemoresistant, and identification of an approach to abrogate this resistance is desired. In search of a compound that rescinds resistance of TICs to mTORC1 inhibition and improves chemotherapy, we identified baicalein (BC), which selectively chemosensitizes TICs and the human hepatocellular carcinoma (HCC) cell line Huh7 cells but not mouse and human primary hepatocytes. Nanobead pull-down and mass-spectrometric analysis, biochemical binding assay, and three-dimensional computational modeling studies reveal BC's ability to competitively inhibit guanosine triphosphate binding of SAR1B guanosine triphosphatase, which is essential for autophagy. Indeed, BC suppresses autophagy induced by an mTORC1 inhibitor and synergizes cell death caused by mTORC1 inhibition in TIC and Huh7 spheroid formation and in the patient-derived xenograft model of HCC. The BC-induced chemosensitization is rescued by SAR1B expression and phenocopied by SAR1B knockdown in cancer cells treated with a mTORC1 inhibitor. Conclusion: These results identify SAR1B as a target in liver TICs and HCC cells resistant to mTORC1 inhibition.

Alcoholic liver disease

Alcoholic liver disease (ALD) is the most prevalent type of chronic liver disease worldwide. ALD can progress from alcoholic fatty liver (AFL) to alcoholic steatohepatitis (ASH), which is characterized by hepatic inflammation. Chronic ASH can eventually lead to fibrosis and cirrhosis and in some cases hepatocellular cancer (HCC). In addition, severe ASH (with or without cirrhosis) can lead to alcoholic hepatitis, which is an acute clinical presentation of ALD that is associated with liver failure and high mortality. Most individuals consuming >40 g of alcohol per day develop AFL; however, only a subset of individuals will develop more advanced disease. Genetic, epigenetic and non-genetic factors might explain the considerable interindividual variation in ALD phenotype. The pathogenesis of ALD includes hepatic steatosis, oxidative stress, acetaldehyde-mediated toxicity and cytokine and chemokine-induced inflammation. Diagnosis of ALD involves assessing patients for alcohol use disorder and signs of advanced liver disease. The degree of AFL and liver fibrosis can be determined by ultrasonography, transient elastography, MRI, measurement of serum biomarkers and liver biopsy histology. Alcohol abstinence achieved by psychosomatic intervention is the best treatment for all stages of ALD. In the case of advanced disease such as cirrhosis or HCC, liver transplantation may be required. Thus, new therapies are urgently needed.

Hepatocyte toll-like receptor 4 deficiency protects against alcohol-induced fatty liver disease

Objective

Recent studies have suggested a critical role for toll-like receptor 4 (TLR4) in the development of alcoholic liver disease. As TLR4 is widely expressed throughout the body, it is unclear which TLR4-expressing cell types contribute to alcohol-induced liver damage.

Methods

We selectively ablated TLR4 in hepatocytes and myeloid cells. Male mice were fed a liquid diet containing either 5% alcohol or pair-fed a control diet for 4 weeks to examine chronic alcohol intake-induced liver damage and inflammation. In addition, mice were administered a single oral gavage of alcohol to investigate acute alcohol drinking-associated liver injury.

Results

We found that selective hepatocyte TLR4 deletion protected mice from chronic alcohol-induced liver injury and fatty liver. This result was in part due to decreased expression of endogenous lipogenic genes and enhanced expression of genes involved in fatty acid oxidation. In addition, mice lacking hepatocyte TLR4 exhibited reduced mRNA expression of inflammatory genes in white adipose tissue. Furthermore, in an acute alcohol binge model, hepatocyte TLR4 deficient mice had significantly decreased plasma alanine transaminase (ALT) levels and attenuated hepatic triglyceride content compared to their alcohol-gavaged control mice. In contrast, deleting TLR4 in myeloid cells did not affect the development of chronic-alcohol induced fatty liver, despite the finding that mice lacking myeloid cell TLR4 had significantly reduced circulating ALT concentrations.

Conclusions

These findings suggest that hepatocyte TLR4 plays an important role in regulating alcohol-induced liver damage and fatty liver disease.

•

Hepatocyte TLR4 ablated mice were protected from both chronic and acute alcohol-induced hepatic triglyceride accumulation.

•

Hepatocyte TLR4 ablated mice showed attenuated inflammation in the fat pad and the circulation after chronic alcohol intake.

•

Loss of TLR4 in myeloid cells did not affect alcohol-induced development of fatty liver.

Pluripotency Transcription Factors and Metabolic Reprogramming of Mitochondria in Tumor-Initiating Stem-like Cells

Significance: Neoplasms contain tumor-initiating stem-like cells (TICs) that drive malignant progression and tumor growth with drug resistance. TICs proliferate through a self-renewal process in which the two daughter cells differ in their proliferative potential, with one retaining the self-renewing phenotype and another displaying the differentiated phenotype. Recent Advances: Cancer traits (hepatocellular carcinoma) are triggered by alcoholism, obesity, and hepatitis B or C virus (HBV and HCV), including genetic changes, angiogenesis, defective tumor immunity, immortalization, metabolic reprogramming, excessive and prolonged inflammation, migration/invasion/metastasis, evasion of cell cycle arrest, anticell death, and compensatory regeneration/proliferation. Critical Issues: This review describes how metabolic reprogramming in mitochondria promotes self-renewal and oncogenicity of TICs. Pluripotency transcription factors (TFs), NANOG, OCT4, MYC, and SOX2, contribute to cancer progression by mitochondrial reprogramming, leading to the genesis of TICs and cancer. For example, oxidative phosphorylation (OXPHOS) and fatty acid metabolism are identified as major pathways contributing to pluripotency TF-mediated oncogenesis. Future Directions: Identification of novel metabolic pathways provides potential drug targets for neutralizing the activity of highly malignant TICs found in cancer patients. Antioxid. Redox Signal. 28, 1080-1089.

A Population-Based Surveillance Study on the Epidemiology of Hepatitis C in Estonia

Background and objective: The hepatitis C virus (HCV)-infected patients serve as a reservoir for transmission of the disease to others and are at risk of developing chronic hepatitis C, cirrhosis, and hepatocellular carcinoma. Although the epidemiological data of high rate HCV infection have been obtained in many countries, such data are insufficient in Estonia. Therefore, the aim of the study was to analyze country-specific data on HCV patients. Materials and methods: Data about age, gender, diagnosis, possible risk factors, coinfections, HCV genotypes, liver fibrosis stages and extrahepatic manifestations were collected from 518 patients. Results: The most common risk factors for hepatitis C were injection drug use and tattooing in the 30–39 and 40–49 year age groups, and blood transfusion in the 50–59 and 60–69 year age groups. The other risk factors established were profession-related factors and sexual contact. The prevailing viral genotype among the HCV infected patients was genotype 1 (69% of the patients) followed by genotype 3 (25%). Genotypes 1 and 3 correlated with blood transfusions before 1994, drug injections and tattooing. Conclusions: Our study provides the best representation of genotype distribution across Estonia. As a result of the study, valuable data has been collected on hepatitis C patients in Estonia.

Ethanol sensitizes hepatocytes for TGF-β-triggered apoptosis

Alcohol abuse is a global health problem causing a substantial fraction of chronic liver diseases. Abundant TGF-β—a potent pro-fibrogenic cytokine—leads to disease progression. Our aim was to elucidate the crosstalk of TGF-β and alcohol on hepatocytes. Primary murine hepatocytes were challenged with ethanol and TGF-β and cell fate was determined. Fluidigm RNA analyses revealed transcriptional effects that regulate survival and apoptosis. Mechanistic insights were derived from enzyme/pathway inhibition experiments and modulation of oxidative stress levels. To substantiate findings, animal model specimens and human liver tissue cultures were investigated. Results: On its own, ethanol had no effect on hepatocyte apoptosis, whereas TGF-β increased cell death. Combined treatment led to massive hepatocyte apoptosis, which could also be recapitulated in human HCC liver tissue treated ex vivo. Alcohol boosted the TGF-β pro-apoptotic gene signature. The underlying mechanism of pathway crosstalk involves SMAD and non-SMAD/AKT signaling. Blunting CYP2E1 and ADH activities did not prevent this effect, implying that it was not a consequence of alcohol metabolism. In line with this, the ethanol metabolite acetaldehyde did not mimic the effect and glutathione supplementation did not prevent the super-induction of cell death. In contrast, blocking GSK-3β activity, a downstream mediator of AKT signaling, rescued the strong apoptotic response triggered by ethanol and TGF-β. This study provides novel information on the crosstalk between ethanol and TGF-β. We give evidence that ethanol directly leads to a boost of TGF-β’s pro-apoptotic function in hepatocytes, which may have implications for patients with chronic alcoholic liver disease.

Alcoholic Liver Disease Accelerates Early Hepatocellular Cancer in a Mouse Model

HCC is a rapidly increasing cancer worldwide. Most HCC rises in the setting of chronic and advanced liver disease caused by viral hepatitis, alcohol use, non-alcoholic liver disease or their combination. We found that in the mouse model, alcohol alone does not induce HCC, however, it can promote HCC development after a carcinogen exposure. Multiple mechanisms are involved in carcinogenesis and alcohol affects many of those including epithelial-mesenchymal transition, cancer stem marker expression and inflammation as evidenced in our HCC model.

Alcohol and Cancer Stem Cells

Heavy alcohol consumption has been associated with increased risk of several cancers, including cancer of the colon, rectum, female breast, oral cavity, pharynx, larynx, liver, and esophagus. It appears that alcohol exposure not only promotes carcinogenesis but also enhances the progression and aggressiveness of existing cancers. The molecular mechanisms underlying alcohol tumor promotion, however, remain unclear. Cancer stem cells (CSC), a subpopulation of cancer cells with self-renewal and differentiation capacity, play an important role in tumor initiation, progression, metastasis, recurrence, and therapy resistance. The recent research evidence suggests that alcohol increases the CSC population in cancers, which may underlie alcohol-induced tumor promotion. This review discusses the recent progress in the research of alcohol promotion of CSC and underlying cellular/molecular mechanisms. The review will further explore the therapeutic potential of CSC inhibition in treating alcohol-induced tumor promotion.