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]

Alcohol, stem cells and cancer

Dosage, gender, and genetic susceptibility to the effects of alcohol remained only partially elucidated. In this review, we summarize the current knowledge of the mechanisms underlying the role of alcohol in liver and gastrointestinal cancers. In addition, two recent pathways- DNA repair and TGF-β signaling which provide new insights into alcohol in the regulation of cancers and stem cells are also discussed here.

The gut microbiome and liver cancer: mechanisms and clinical translation

Hepatocellular carcinoma (HCC) is the third leading cause of worldwide cancer mortality. HCC almost exclusively develops in patients with chronic liver disease, driven by a vicious cycle of liver injury, inflammation and regeneration that typically spans decades. Increasing evidence points towards a key role of the bacterial microbiome in promoting the progression of liver disease and the development of HCC. Here, we will review mechanisms by which the gut microbiota promotes hepatocarcinogenesis, focusing on the leaky gut, bacterial dysbiosis, microbe-associated molecular patterns and bacterial metabolites as key pathways that drive cancer-promoting liver inflammation, fibrosis and genotoxicity. On the basis of accumulating evidence from preclinical studies, we propose the intestinal-microbiota-liver axis as a promising target for the simultaneous prevention of chronic liver disease progression and HCC development in patients with advanced liver disease. We will review in detail therapeutic modalities and discuss clinical settings in which targeting the gut-microbiota-liver axis for the prevention of disease progression and HCC development seems promising.

Abnormal expression of TFIIIB subunits and RNA Pol III genes is associated with hepatocellular carcinoma

The levels of the products of RNA polymerase III-dependent genes (Pol III genes), including tRNAs and 5S rRNA, are elevated in transformed and tumor cells, which potentiate tumorigenesis. TFIIB-related factor 1 (Brf1) is a key transcription factor and specifically regulates the transcription of Pol III genes. In vivo and in vitro studies have demonstrated that a decrease in Brf1 reduces Pol III gene transcription and is sufficient for inhibiting cell transformation and tumor formation. Emerging evidence indicates that dysregulation of Brf1 and Pol III genes is linked to the development of hepatocellular carcinoma (HCC) in humans and animals. We have reported that Brf1 is overexpressed in human liver cancer patients and that those with high Brf1 levels have shorter survivals. This review summarizes the effects of dysregulation of these genes on HCC and their regulation by signaling pathways and epigenetics. These novel data should help us determine the molecular mechanisms of HCC from a different perspective and guide the development of therapeutic approaches for HCC patients.

Exploring a common mechanism of alcohol-induced deregulation of RNA Pol III genes in liver and breast cells

Alcohol intake is associated with numbers of different human cancers, such as hepatocellular carcinoma (HCC) and breast cancer. However, the molecular mechanism remains to be elucidated. RNA polymerase III-dependent genes (Pol III genes) deregulation elevates cellular production of tRNAs and 5S rRNA, resulting in an increase in translational capacity, which promote cell transformation and tumor formation. To explore a common mechanism of alcohol-associated human cancers, we have comparably analyzed that alcohol causes deregulation of Pol III genes in liver and breast cells. Our results reveal that alcohol enhances RNA Pol III gene transcription in both liver and breast cells. The induction of Pol III genes caused by alcohol in ER+ breast cancer lines or liver tumor lines are significantly higher than in their non-tumor cell lines. Alcohol increases cellular levels of Brf1 mRNA and protein, (which depeted) Brf1 is a key transcription factor and specifically regulate Pol III gene activity. Alcohol activates JNK1 to upregulate transcription of Brf1 and Pol III genes, whereas inhibition of JNK1 by SP600125 or its siRNA significantly decreases the induction of these genes. Furthermore, alcohol increases the rates of transformation of liver and breast cells, repressed JNK1 and Brf1 expression decrease transcription of Pol III genes and reduce the rates of colony formation of AML-12 and MCF-10 cells. Together, these studies support the idea that alcohol induces deregulation of Brf1 and RNA Pol III genes in liver and breast cells, which share a common signaling pathway to promote cell transformation. Through the common mechanism, alcohol-induced deregulation of RNA Pol III genes brings about greater phenotypic changes.

High-mobility-group protein 2 regulated by microRNA-127 and small heterodimer partner modulates pluripotency of mouse embryonic stem cells and liver tumor initiating cells

High‐mobility‐group protein 2 (HMGB2) expression is up‐regulated in human liver cancer; however, little is known about its regulatory function. Here, we establish HMGB2 as a new modulator of the pluripotency of mouse embryonic stem cells. Similar to octamer‐binding transcription factor 4 (OCT4) and sex‐determining region Y‐box 2 (SOX2), HMGB2 protein is highly expressed in undifferentiated CGR8 cells, whereas it undergoes rapid decline during embryonic body formation. HMGB2 interacts with OCT4, increases protein expression of OCT4 and SOX2, and enhances their transcriptional activities. We also show that microRNA (miRNA)‐127 is a translational repressor of HMGB2 protein expression by targeting its 3′ untranslated region. We further elucidate a transcriptional mechanism controlling HMGB2 messenger RNA expression by the nuclear receptor small heterodimer partner (SHP) and transcription factor E2F1. Diminishing HMGB2 expression by ectopic expression of miR‐127 or SHP or treatment with the small molecule inhibitor inflachromene decreases OCT4 and SOX2 expression and facilitates CGR8 differentiation. In addition, HMGB2 is markedly induced in liver tumor initiating cells. Diminishing HMGB2 expression by short hairpin RNA for HMGB2 (shHMGB2), miR‐127, or SHP impairs spheroid formation. Importantly, HMGB2 expression is elevated in various human cancers. Conclusion: HMGB2 acts upstream of OCT4/SOX2 signaling to control embryonic stem cell pluripotency. Diminishing HMGB2 expression by miR‐127 or SHP may provide a potential means to decrease the pluripotency of tumor initiating cells. (Hepatology Communications 2017;1:816–830)

Combined use of alcohol in conventional chemical-induced mouse liver cancer model improves the simulation of clinical characteristics of human hepatocellular carcinoma

Liver cancer is the one of most common types of cancer and the 2nd cause of cancer-associated mortalities worldwide. Establishing appropriate animal models of liver cancer is essential for basic and translational studies. The present study evaluated the effects of the combined use of alcohol with a conventional chemical-induced mouse liver cancer model. The treatment of alcohol/diethylnitrosamine (DEN)/carbon tetrachloride (CCl₄) in the mice of experimental groups resulted in a series of pathological changes in the liver. Liver inflammation, fibrosis, cirrhosis and hepatocellular carcinoma were identified, and this method used less time (1–5 months) for inducement compared with the conventional chemical-induced method alone. In addition, murine α-fetoprotein (mAFP) was expressed throughout and ultrastructural features met the criteria for liver cancer. Fatty degeneration of pancreas, reduced blood glucose levels, and increased spleen weight were observed. These results indicated that an AFP-secreting hepatocellular carcinoma model of BALB/c mouse was successfully developed. The disease process and morphological changes met the criterion of the liver cancer process. Therefore the model developed in the present study may be an ideal animal model for studying the occurrence and development of liver cancer.

Toll like receptor 4 and hepatocellular carcinoma; A systematic review

INTRODUCTION

Toll like receptor 4 (TLR4) is an extracellular pathogen recognition receptor (PRR) which recognizes a wide range of pathogens and damage associated molecular patterns (PAMPs and DAMPs). It can activate intracellular signaling and consequently transcription factors which participate in transcription from either immune related or malignancy genes. Thus, it has been hypothesized that TLR4 may be a cause of hepatocellular carcinoma (HCC). This article has reviewed the roles of TLR4 in the pathogenesis of HCC.

METHOD

"TLR4", "hepatocellular carcinoma", "liver tumor" and "liver cancer" were used as key words for searching in Scopus, Google Scholar and MEDLINE scientific databases.

RESULTS

Most of the investigations documented the roles of TLR4 in induction of HCC via several mechanisms including increased number of T regulatory lymphocytes and liver resident follicular helper like cells, increased production of pro-inflammatory and malignancy related molecules including cytokines, NANOG, Caspase-1, Ephrin-A1, NO and BCL6. TLR4 participates in the proliferation of the cells and also production of the molecules in both chronic infectious and non-infectious inflammatory diseases.

DISCUSSION

TLR4 is an innate immunity receptor which plays a pathogenic role during chronic inflammation and can induce HCC in human.

Hepatitis C virus core protein targets 4E-BP1 expression and phosphorylation and potentiates Myc-induced liver carcinogenesis in transgenic mice

Hepatitis C virus (HCV) is a leading cause of liver diseases including the development of hepatocellular carcinoma (HCC). Particularly, core protein has been involved in HCV-related liver pathologies. However, the impact of HCV core on signaling pathways supporting the genesis of HCC remains largely elusive. To decipher the host cell signaling pathways involved in the oncogenic potential of HCV core, a global quantitative phosphoproteomic approach was carried out. This study shed light on novel differentially phosphorylated proteins, in particular several components involved in translation. Among the eukaryotic initiation factors that govern the translational machinery, 4E-BP1 represents a master regulator of protein synthesis that is associated with the development and progression of cancers due to its ability to increase protein expression of oncogenic pathways. Enhanced levels of 4E-BP1 in non-modified and phosphorylated forms were validated in human hepatoma cells and in mouse primary hepatocytes expressing HCV core, in the livers of HCV core transgenic mice as well as in HCV-infected human primary hepatocytes. The contribution of HCV core in carcinogenesis and the status of 4E-BP1 expression and phosphorylation were studied in HCV core/Myc double transgenic mice. HCV core increased the levels of 4E-BP1 expression and phosphorylation and significantly accelerated the onset of Myc-induced tumorigenesis in these double transgenic mice. These results reveal a novel function of HCV core in liver carcinogenesis potentiation. They position 4E-BP1 as a tumor-specific target of HCV core and support the involvement of the 4E-BP1/eIF4E axis in hepatocarcinogenesis.

Transgenic overexpression of NanogP8 in the mouse prostate is insufficient to initiate tumorigenesis but weakly promotes tumor development in the Hi-Myc mouse model

This project was undertaken to address a critical cancer biology question: Is overexpression of the pluripotency molecule Nanog sufficient to initiate tumor development in a somatic tissue? Nanog1 is critical for the self-renewal and pluripotency of ES cells, and its retrotransposed homolog, NanogP8 is preferentially expressed in somatic cancer cells. Our work has shown that shRNA-mediated knockdown of NanogP8 in prostate, breast, and colon cancer cells inhibits tumor regeneration whereas inducible overexpression of NanogP8 promotes cancer stem cell phenotypes and properties. To address the key unanswered question whether tissue-specific overexpression of NanogP8 is sufficient to promote tumor development in vivo, we generated a NanogP8 transgenic mouse model, in which the ARR₂PB promoter was used to drive NanogP8 cDNA. Surprisingly, the ARR₂PB-NanogP8 transgenic mice were viable, developed normally, and did not form spontaneous tumors in >2 years. Also, both wild type and ARR₂PB-NanogP8 transgenic mice responded similarly to castration and regeneration and castrated ARR₂PB-NanogP8 transgenic mice also did not develop tumors. By crossing the ARR₂PB-NanogP8 transgenic mice with ARR₂PB-Myc (i.e., Hi-Myc) mice, we found that the double transgenic (i.e., ARR₂PB-NanogP8; Hi-Myc) mice showed similar tumor incidence and histology to the Hi-Myc mice. Interestingly, however, we observed white dots in the ventral lobes of the double transgenic prostates, which were characterized as overgrown ductules/buds featured by crowded atypical Nanog-expressing luminal cells. Taken together, our present work demonstrates that transgenic overexpression of NanogP8 in the mouse prostate is insufficient to initiate tumorigenesis but weakly promotes tumor development in the Hi-Myc mouse model.

Role of cytokines and chemokines in alcohol-induced tumor promotion

Excessive chronic alcohol consumption has become a worldwide health problem. The oncogenic effect of chronic alcohol consumption is one of the leading concerns. The mechanisms of alcohol-induced tumorigenesis and tumor progression are largely unknown, although many factors have been implicated in the process. This review discusses the recent progress in this research area with concentration on alcohol-induced dysregulation of cytokines and chemokines. Based on the available evidence, we propose that alcohol promotes tumor progression by the dysregulation of the cytokine/chemokine system. In addition, we discuss specific transcription factors and signaling pathways that are involved in the action of these cytokines/chemokines and the oncogenic effect of alcohol. This review provides novel insight into the mechanisms of alcohol-induced tumor promotion.

Differences in IP‑10, TLR4 and IRF5/3 between SVR and non‑SVR HCV‑1 patients treated with PEG‑IFN and ribavirin

The present study aimed to investigate alterations in Toll‑like receptor 4 (TLR4), interferon regulatory factor 5 (IRF5) and interferon‑γ‑inducible protein‑10 (IP‑10), and evaluate whether these factors may be associated with a sustained virological response (SVR) among patients with hepatitis C virus genotype‑1 (HCV‑1) who were treated with peginterferon plus ribavirin (PEG‑IFN‑RBV). A total of 31 Chinese patients infected with HCV‑1 were enrolled in the present study and 25 patients obtained SVR. The expression levels of IP‑10 declined significantly during PEG‑IFN‑RBV therapy at the 24 and 48 week time‑points, compared with the baseline (P<0.005, 0.001 and 0.001, respectively). In addition, it was observed that IRF5 mRNA expression and the number of TLR4+ peripheral blood mononuclear cells exhibited similar correlations with IP‑10 concentration (R2=0.0726, P=0.001, R2=0.1634, P<0.0001, respectively) in the SVR group patients; however, these correlations were not observed to be present in the non‑SVR group patients. In conclusion, the results of the present study suggest that marked alterations in IP‑10, TLR4 and IRF5 expression may serve as indicators for the development of SVR in patients with HCV‑1 treated with PEG‑IFN‑RBV.

Nonstructural 5A Protein of Hepatitis C Virus Interferes with Toll-Like Receptor Signaling and Suppresses the Interferon Response in Mouse Liver

The hepatitis C virus nonstructural protein NS5A is involved in resistance to the host immune response, as well as the viral lifecycle such as replication and maturation. Here, we established transgenic mice expressing NS5A protein in the liver and examined innate immune responses against lipopolysaccharide (LPS) in vivo. Intrahepatic gene expression levels of cytokines such as interleukin-6, tumor necrosis factor-α, and interferon-γ were significantly suppressed after LPS injection in the transgenic mouse liver. Induction of the C-C motif chemokine ligand 2, 4, and 5 was also suppressed. Phosphorylation of the signal transducer and activator of transcription 3, which is activated by cytokines, was also reduced, and expression levels of interferon-stimulated genes, 2’-5’ oligoadenylate synthase, interferon-inducible double-stranded RNA-activated protein kinase, and myxovirus resistance 1 were similarly suppressed. Since LPS binds to toll-like receptor 4 and stimulates the downstream pathway leading to induction of these genes, we examined the extracellular signal-regulated kinase and IκB-α. The phosphorylation levels of these molecules were reduced in transgenic mouse liver, indicating that the pathway upstream of the molecules was disrupted by NS5A. Further analyses revealed that the interaction between interleukin-1 receptor-associated kinase-1 and tumor necrosis factor receptor associated factor-6 was dispersed in transgenic mice, suggesting that NS5A may interfere with this interaction via myeloid differentiation primary response gene 88, which was shown to interact with NS5A. Since the gut microbiota, a source of LPS, is known to be associated with pathological conditions in liver diseases, our results suggest the involvement of NS5A in the pathogenesis of HCV infected-liver via the suppression of innate immunity.

The relationship between expression of Toll-like receptor 4 in chronic hepatitis C patients and different stages of liver fibrosis

AIM

The objective of this work is to find out whether there is a relation between the expression of TLR4 and fibrosis progression in chronic HCV patients.

BACKGROUND

Toll-like Receptor 4 (TLR4) is a pattern recognition receptor whose activation results in the production of several pro-inflammatory cytokines.

METHODS

Fifty patients with chronic HCV were included. They were divided into group A: 40 patients (F1-F4) and group B (control group) which included ten patients (F0) based on fibroscan value. All patients were exposed to clinical and laboratory evaluations preliminary to antiviral therapy, assessment of TLR4 mRNA by Real Time- PCR.

RESULTS

Twenty-eight males and 22 females with a mean age 28.9±6.1 years. The mean TLR4 expression is 11.2±7.4 folds, TLR4 expression in F0 group is 2.8±1.9, in F1 group 4.8±1.5, F2 group 10.2±2.5, F3 group 16.8±1.5 and in F4 21.3±3.6 folds (p<0.001). TLR4 showed a positive correlation with age, fibrosis stage, HCV RNA, serum transaminases, total bilirubin and prothrombin time, a negative correlation with platelet count and serum albumin. Fibrosis progression was independently associated with TLR4 expression (β=0. 648, P<0.0001), RNA (β= 0.160, P =0.001) and platelet count (β= -0.248, P = 0.004).

CONCLUSION

The expression of TLR4 is highly correlated with the fibrosis progression; TLR4 may be a potential target for drugs to limit the progression of fibrosis.

Long-term exposure of MCF-7 breast cancer cells to ethanol stimulates oncogenic features

Alcohol consumption is a risk factor for breast cancer. Little is known regarding the mechanism, although it is assumed that acetaldehyde or estrogen mediated pathways play a role. We previously showed that long-term exposure to 2.5 mM ethanol (blood alcohol ~0.012%) of MCF-12A, a human normal epithelial breast cell line, induced epithelial mesenchymal transition (EMT) and oncogenic transformation. In this study, we investigated in the human breast cancer cell line MCF-7, whether a similar exposure to ethanol at concentrations ranging up to peak blood levels in heavy drinkers would increase malignant progression. Short-term (1-week) incubation to ethanol at as low as 1-5 mM (corresponding to blood alcohol concentration of ~0.0048-0.024%) upregulated the stem cell related proteins Oct4 and Nanog, but they were reduced after exposure at 25 mM. Long-term (4-week) exposure to 25 mM ethanol upregulated the Oct4 and Nanog proteins, as well as the malignancy marker Ceacam6. DNA microarray analysis in cells exposed for 1 week showed upregulated expression of metallothionein genes, particularly MT1X. Long-term exposure upregulated expression of some malignancy related genes (STEAP4, SERPINA3, SAMD9, GDF15, KRT15, ITGB6, TP63, and PGR, as well as the CEACAM, interferon related, and HLA gene families). Some of these findings were validated by RT-PCR. A similar treatment also modulated numerous microRNAs (miRs) including one regulator of Oct4 as well as miRs involved in oncogenesis and/or malignancy, with only a few estrogen-induced miRs. Long-term 25 mM ethanol also induced a 5.6-fold upregulation of anchorage-independent growth, an indicator of malignant-like features. Exposure to acetaldehyde resulted in little or no effect comparable to that of ethanol. The previously shown alcohol induction of oncogenic transformation of normal breast cells is now complemented by the current results suggesting alcohol's potential involvement in malignant progression of breast cancer.

Toll-like receptors in pathophysiology of liver diseases

Toll-like receptors (TLRs) are pattern recognition receptors that participate in host defense by recognizing pathogen-associated molecular patterns alongside inflammatory processes by recognizing damage associated molecular patterns. Given constant exposure to pathogens from gut, strict control of TLR-associated signaling pathways is essential in the liver, which otherwise may lead to inappropriate production of pro-inflammatory cytokines and interferons and may generate a predisposition to several autoimmune and chronic inflammatory diseases. The liver is considered to be a site of tolerance induction rather than immunity induction, with specificity in hepatic cell functions and distribution of TLR. Recent data emphasize significant contribution of TLR signaling in chronic liver diseases via complex immune responses mediating hepatocyte (i.e., hepatocellular injury and regeneration) or hepatic stellate cell (i.e., fibrosis and cirrhosis) inflammatory or immune pathologies. Herein, we review the available data on TLR signaling, hepatic expression of TLRs and associated ligands, as well as the contribution of TLRs to the pathophysiology of hepatic diseases.

Alcohol use disorder and its impact on chronic hepatitis C virus and human immunodeficiency virus infections

Alcohol use disorder (AUD) and hepatitis C virus (HCV) infection frequently co-occur. AUD is associated with greater exposure to HCV infection, increased HCV infection persistence, and more extensive liver damage due to interactions between AUD and HCV on immune responses, cytotoxicity, and oxidative stress. Although AUD and HCV infection are associated with increased morbidity and mortality, HCV antiviral therapy is less commonly prescribed in individuals with both conditions. AUD is also common in human immunodeficiency virus (HIV) infection, which negatively impacts proper HIV care and adherence to antiretroviral therapy, and liver disease. In addition, AUD and HCV infection are also frequent within a proportion of patients with HIV infection, which negatively impacts liver disease. This review summarizes the current knowledge regarding pathological interactions of AUD with hepatitis C infection, HIV infection, and HCV/HIV co-infection, as well as relating to AUD treatment interventions in these individuals.

Toll-like Receptor (TLR) Signaling Interacts with CREBH to Modulate High-density Lipoprotein (HDL) in Response to Bacterial Endotoxin

Bacterial endotoxin can induce inflammatory and metabolic changes in the host. In this study, we revealed a molecular mechanism by which a stress-inducible, liver-enriched transcription factor, cAMP-responsive element-binding protein hepatic-specific (CREBH), modulates lipid profiles to protect the liver from injuries upon the bacterial endotoxin lipopolysaccharide (LPS). LPS challenge can activate CREBH in mouse liver tissues in a toll-like receptor (TLR)/MyD88-dependent manner. Upon LPS challenge, CREBH interacts with TNF receptor-associated factor 6 (TRAF6), an E3 ubiquitin ligase that functions as a key mediator of TLR signaling, and this interaction relies on MyD88. Further analysis demonstrated that TRAF6 mediates K63-linked ubiquitination of CREBH to facilitate CREBH cleavage and activation. CREBH directly activates expression of the gene encoding Apolipoprotein A4 (ApoA4) under LPS challenge, leading to modulation of high-density lipoprotein (HDL) in animals. CREBH deficiency led to reduced production of circulating HDL and increased liver damage upon high-dose LPS challenge. Therefore, TLR/MyD88-dependent, TRAF6-facilitated CREBH activation represents a mammalian hepatic defense response to bacterial endotoxin by modulating HDL.

Pathogenesis of Alcoholic Liver Disease

Alcoholic liver disease includes a broad clinical-histological spectrum from simple steatosis, cirrhosis, acute alcoholic hepatitis with or without cirrhosis to hepatocellular carcinoma as a complication of cirrhosis. The pathogenesis of alcoholic liver disease can be conceptually divided into (1) ethanol-mediated liver injury, (2) inflammatory immune response to injury, (3) intestinal permeability and microbiome changes. Corticosteroids may improve outcomes, but this is controversial and probably only impacts short-term survival. New pathophysiology-based therapies are under study, including antibiotics, caspase inhibition, interleukin-22, anakinra, FXR agonist and others. These studies provide hope for better future outcomes for this difficult disease.

Obesity and cancer: inflammation bridges the two

Obesity is a growing public health problem and affects 35% US adults. Obesity increases the risk of many cancer types and is associated with poor outcomes. Clinical management of cancer patients has been essentially the same between normal weight and obese individuals. Understanding causal mechanisms by which obesity drives cancer initiation and progression is essential for the development of novel precision therapy for obese cancer patients. One caveat is that various mechanisms have been proposed for different cancer types for their progression under obesity. Since obesity is known to have global impact on inflammation, here we will summarize recent literature and discuss the potential of inflammation being the common causal mechanism to promote cancer promotion across cancer types.

Lipopolysaccharide supports maintaining the stemness of CD133(+) hepatoma cells through activation of the NF-κB/HIF-1α pathway

Due to the existence of cancer stem cells (CSCs), persistence and relapse of human hepatocellular carcinoma (HCC) are common after treatment with existing anti-cancer therapies. Emerging evidence indicates that lipopolysaccharide (LPS) plays a crucial role in aggravating HCC, but information about the effect of LPS on CSCs of HCC remains scant. Here, we report that the stemness of CD133(+) CSCs sorted from the human HCC cell line Huh7 was maintained well when cells were cultured with LPS. The reduction of CD133 expression was much lesser in cultured CSCs in the presence of LPS. In response to LPS stimulation, CSCs showed an increase in their activity of clonogenesis and tumorigenesis. LPS also supported maintaining CSC abilities of migration, invasion, and chemo-resistance. Treatment with HIF-1α-specific siRNA significantly reduced CD133 expression by CSCs at both mRNA and protein levels. Further, the expression of HIF-1α and CD133 was reduced in LPS-stimulated CSCs when the NF-κB inhibitor was added to the cell culture. HIF-1α-specific siRNA also effectively counteracted the effect of LPS on maintaining CSC abilities of migration and invasion. These data indicate that LPS, an important mediator in the liver tumor microenvironment, supports the maintenance of CSC stemness through signaling of the NF-κB/HIF-1α pathway. Our current study highlights LPS as a potential target for developing new therapeutic approaches to eliminate CSCs during the treatment of HCC.

Adult mouse model of early hepatocellular carcinoma promoted by alcoholic liver disease

AIM

To establish a mouse model of alcohol-driven hepatocellular carcinoma (HCC) that develops in livers with alcoholic liver disease (ALD).

METHODS

Adult C57BL/6 male mice received multiple doses of chemical carcinogen diethyl nitrosamine (DEN) followed by 7 wk of 4% Lieber-DeCarli diet. Serum alanine aminotransferase (ALT), alpha fetoprotein (AFP) and liver Cyp2e1 were assessed. Expression of F4/80, CD68 for macrophages and Ly6G, MPO, E-selectin for neutrophils was measured. Macrophage polarization was determined by IL-1β/iNOS (M1) and Arg-1/IL-10/CD163/CD206 (M2) expression. Liver steatosis and fibrosis were measured by oil-red-O and Sirius red staining respectively. HCC development was monitored by magnetic resonance imaging, confirmed by histology. Cellular proliferation was assessed by proliferating cell nuclear antigen (PCNA).

RESULTS

Alcohol-DEN mice showed higher ALTs than pair fed-DEN mice throughout the alcohol feeding without weight gain. Alcohol feeding resulted in increased ALT, liver steatosis and inflammation compared to pair-fed controls. Alcohol-DEN mice had reduced steatosis and increased fibrosis indicating advanced liver disease. Molecular characterization showed highest levels of both neutrophil and macrophage markers in alcohol-DEN livers. Importantly, M2 macrophages were predominantly higher in alcohol-DEN livers. Magnetic resonance imaging revealed increased numbers of intrahepatic cysts and liver histology confirmed the presence of early HCC in alcohol-DEN mice compared to all other groups. This correlated with increased serum alpha-fetoprotein, a marker of HCC, in alcohol-DEN mice. PCNA immunostaining revealed significantly increased hepatocyte proliferation in livers from alcohol-DEN compared to pair fed-DEN or alcohol-fed mice.

CONCLUSION

We describe a new 12-wk HCC model in adult mice that develops in livers with alcoholic hepatitis and defines ALD as co-factor in HCC.

The rationale for targeting TGF-β in chronic liver diseases

BACKGROUND

Transforming growth factor (TGF)-β is a pluripotent cytokine that displays several tissue-specific biological activities. In the liver, TGF-β is considered a fundamental molecule, controlling organ size and growth by limiting hepatocyte proliferation. It is involved in fibrogenesis and, therefore, in worsening liver damage, as well as in triggering the development of hepatocellular carcinoma (HCC). TGF-β is known to act as an oncosuppressor and also as a tumour promoter in HCC, but its role is still unclear.

DESIGN

In this review, we discuss the potential role of TGF-β in regulating the tumoural progression of HCC, and therefore the rationale for targeting this molecule in patients with HCC.

RESULTS

A considerable amount of experimental preclinical evidence suggests that TGF-β is a promising druggable target in patients with HCC. To support this hypothesis, a phase II clinical trial is currently ongoing using a TGF-β pathway inhibitor, and results will soon be available.

CONCLUSIONS

The identification of new TGF-β related biomarkers will help to select those patients most likely to benefit from therapy aimed at inhibiting the TGF-β pathway. New formulations that may provide a more controlled and sustained delivery of the drug will improve the therapeutic success of such treatments.

TLR4 Signaling via NANOG Cooperates With STAT3 to Activate Twist1 and Promote Formation of Tumor-Initiating Stem-Like Cells in Livers of Mice

BACKGROUND & AIMS

Obesity and alcohol consumption contribute to steatohepatitis, which increases the risk for hepatitis C virus (HCV)-associated hepatocellular carcinomas (HCCs). Mouse hepatocytes that express HCV-NS5A in liver up-regulate the expression of Toll-like receptor 4 (TLR4), and develop liver tumors containing tumor-initiating stem-like cells (TICs) that express NANOG. We investigated whether the TLR4 signals to NANOG to promote the development of TICs and tumorigenesis in mice placed on a Western diet high in cholesterol and saturated fat (HCFD).

METHODS

We expressed HCV-NS5A from a transgene (NS5A Tg) in Tlr4-/- (C57Bl6/10ScN), and wild-type control mice. Mice were fed a HCFD for 12 months. TICs were identified and isolated based on being CD133+, CD49f+, and CD45-. We obtained 142 paraffin-embedded sections of different stage HCCs and adjacent nontumor areas from the same patients, and performed gene expression, immunofluorescence, and immunohistochemical analyses.

RESULTS

A higher proportion of NS5A Tg mice developed liver tumors (39%) than mice that did not express HCV NS5A after the HCFD (6%); only 9% of Tlr4-/- NS5A Tg mice fed HCFD developed liver tumors. Livers from NS5A Tg mice fed the HCFD had increased levels of TLR4, NANOG, phosphorylated signal transducer and activator of transcription (pSTAT3), and TWIST1 proteins, and increases in Tlr4, Nanog, Stat3, and Twist1 messenger RNAs. In TICs from NS5A Tg mice, NANOG and pSTAT3 directly interact to activate expression of Twist1. Levels of TLR4, NANOG, pSTAT3, and TWIST were increased in HCC compared with nontumor tissues from patients.

CONCLUSIONS

HCFD and HCV-NS5A together stimulated TLR4-NANOG and the leptin receptor (OB-R)-pSTAT3 signaling pathways, resulting in liver tumorigenesis through an exaggerated mesenchymal phenotype with prominent Twist1-expressing TICs.

Alcoholic hepatitis accelerates early hepatobiliary cancer by increasing stemness and miR-122-mediated HIF-1α activation

Alcohol-related hepatocellular carcinoma (HCC) develops with advanced alcoholic liver disease and liver fibrosis. Using adult mice, we evaluate the effect of alcoholic steatohepatitis on early hepatobiliary carcinoma after initiation by diethyl-nitrosamine (DEN). Here we show that alcohol-fed DEN-injected mice have higher ALT and liver-to-body weight ratio compared to pair-fed DEN-injected mice. Alcohol feeding results in steatohepatitis indicated by increased pro-inflammatory cytokines and fibrotic genes. MRI and liver histology of alcohol+DEN mice shows hepatobiliary cysts, early hepatic neoplasia and increase in serum alpha-fetoprotein. Proliferation makers (BrdU, cyclin D1, p53) and cancer stem cell markers (CD133 and nanog) are significantly up-regulated in livers of alcohol-fed DEN-injected mice compared to controls. In livers with tumors, loss of miR-122 expression with a significant up-regulation of miR-122 target HIF-1α is seen. We conclude that alcoholic steatohepatitis accelerates hepatobiliary tumors with characteristic molecular features of HCC by up-regulating inflammation, cell proliferation, stemness, and miR-122 loss.

The significance of Brf1 overexpression in human hepatocellular carcinoma

Brf1 (TFIIB-related factor 1) plays a crucial role in cell transformation and tumorigenesis. However, the significance of Brf1 expression in human HCC (hepatocellular carcinoma) cases remains to be addressed. In this study, biopsies of human HCC, liver tumor samples of mice and cell lines of normal and tumor liver were utilized to determine the alteration of Brf1 expression using cytological and molecular biological approaches. Brf1 expression is increased in human HCC cases, which is correlated with shorter survival times. Levels of Brf1 and Pol III (RNA polymerase III-dependent) gene transcription in HCC patients with alcohol consumption are higher than the cases of non-HCC with or without alcohol intake. Induction of Brf1 and Pol III genes by ethanol in hepatoma cells is higher than in non-tumor cells. Ethanol increases the rate of cell transformation. Repression of Brf1 inhibits alcohol-promoted cell transformation. Alcohol consumption enhances Brf1 expression to promote cell transformation. These studies demonstrate that Brf1 is a new biomarker of HCC.

Significance of hepatitis virus infection in the oncogenic initiation of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Chronic infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) is a major risk factor in the development of the HCC, independently from excessive alcohol abuse and metabolic disease. Since the biology of HBV and HCV is different, their oncogenic effect may go through different mechanisms, direct and/or indirect. Viral hepatitis infection is associated with cellular inflammation, oxidative stress, and DNA damage, that may lead to subsequent hepatic injuries such as chronic hepatitis, fibrosis, cirrhosis, and finally HCC. Direct oncogenic properties of these viruses are related with their genotypic characteristics and the ability of viral proteins to interact with host proteins, thus altering the molecular pathways balance of the cells. In addition, the integration of HBV DNA, especially the gene S and X, in a particular site of the host genome can disrupt chromosomal stability and may activate various oncogenic mechanisms, including those in hematopoietic cells. Recently, several studies also had demonstrated that viral hepatitis could trigger the population of hepatic cancer stem cells. This review summarize available pre-clinical and clinical data in literature regarding oncogenic properties of HBV and HCV in the early initiation of HCC.

NANOG Metabolically Reprograms Tumor-Initiating Stem-like Cells through Tumorigenic Changes in Oxidative Phosphorylation and Fatty Acid Metabolism

Stem cell markers, including NANOG, have been implicated in various cancers; however, the functional contribution of NANOG to cancer pathogenesis has remained unclear. Here, we show that NANOG is induced by Toll-like receptor 4 (TLR4) signaling via phosphorylation of E2F1 and that downregulation of Nanog slows down hepatocellular carcinoma (HCC) progression induced by alcohol western diet and hepatitis C virus protein in mice. NANOG ChIP-seq analyses reveal that NANOG regulates the expression of genes involved in mitochondrial metabolic pathways required to maintain tumor-initiating stem-like cells (TICs). NANOG represses mitochondrial oxidative phosphorylation (OXPHOS) genes, as well as ROS generation, and activates fatty acid oxidation (FAO) to support TIC self-renewal and drug resistance. Restoration of OXPHOS activity and inhibition of FAO renders TICs susceptible to a standard care chemotherapy drug for HCC, sorafenib. This study provides insights into the mechanisms of NANOG-mediated generation of TICs, tumorigenesis, and chemoresistance through reprogramming of mitochondrial metabolism.

Starring role of toll-like receptor-4 activation in the gut-liver axis

Since the introduction of the term “gut-liver axis”, many studies have focused on the functional links of intestinal microbiota, barrier function and immune responses to liver physiology. Intestinal and extra-intestinal diseases alter microbiota composition and lead to dysbiosis, which aggravates impaired intestinal barrier function via increased lipopolysaccharide translocation. The subsequent increased passage of gut-derived product from the intestinal lumen to the organ wall and bloodstream affects gut motility and liver biology. The activation of the toll-like receptor 4 (TLR-4) likely plays a key role in both cases. This review analyzed the most recent literature on the gut-liver axis, with a particular focus on the role of TLR-4 activation. Findings that linked liver disease with dysbiosis are evaluated, and links between dysbiosis and alterations of intestinal permeability and motility are discussed. We also examine the mechanisms of translocated gut bacteria and/or the bacterial product activation of liver inflammation and fibrogenesis via activity on different hepatic cell types.

NF-κB-DICER-miRs Axis Regulates TNF-α Expression in Responses to Endotoxin Stress

Unbalanced tumor necrosis factor (TNF)-α production is associated with pathogenesis of a variety of human diseases. However, the molecular pathways maintaining TNF-α homeostasis remain elusive. Here, we report that NF-κB/p65-DICER-miRs axis negatively regulates TNF-α production. We demonstrated that NF-κB bound to DICER promoter and transcriptionally regulated DICER expression. In addition, the NF-κB/DICER signaling suppresses TNF-α expression by generating mature forms of miR-125b and miR-130a which negatively regulate TNF-α mRNA. Furthermore, we showed that the hepatocyte-specific depletion of Dicer in mice resulted in TNF-α overproduction and sensitized the mice to endotoxin, which could be corrected by administration of miR-125b mimics. These data suggest that NF-κB/p65-DICER-miRs axis involved in maintaining of TNF-α homeostasis, and injection of miR-125b as a potential therapeutic method for septic shock.

Mechanisms of alcohol-induced hepatocellular carcinoma

Chronic alcohol abuse is a major risk factor for hepatocellular carcinoma (HCC), the third leading cause of cancer deaths worldwide. Alcohol can also function synergistically with other risk factors to cause HCC. Hence, alcohol consumption is a major factor affecting hepatic carcinogenesis in millions and the cause of a substantial public health burden. Chronic alcohol consumption interferes with several host anti-tumor mechanisms, thereby facilitating hepatocyte proliferation and tumorigenesis. This review summarizes the major mechanisms of alcohol-induced HCC. These include pathways of ethanol metabolism, alcohol-induced oxidative stress and hypomethylation of DNA, and interplay of alcohol with iron elevation, retinoid metabolism, the immune system, inflammatory pathways, and neoangiogenesis. The relevance of each pathway in affecting HCC transformation is a topic of intense investigation. Ongoing research will enhance our insight into the alcohol-induced occurrence of HCC and offer hope in developing better therapeutics.

Proteomic identification of differentially expressed proteins in rat hepatocarcinogenesis using iTRAQ technology

AIM: To identify differentially expressed proteins in rat hepatocarcinogenesis.

METHODS: Sprague-Dawley rats were randomly divided into a diethylinitrosamine (DEN) group and a normal control group. The DEN group was administrated 0.01% DEN solution in water for 18 wk, and the control group was given vehicle. The animals were sacrificed at the end of the 4^th, 10^th, 12^th, or 18^th week. Liver tissue proteins were quantified and identified using the isobaric tags for relative an absolute quantitation (iTRAQ) technology with two dimensional liquid chromatography-tandem mass spectrometry (2DLC-MS/MS). The functions of differentially expressed proteins were analyzed by bioinformatics.

RESULTS: A total of 530 proteins were identified by MS, and the numbers of differentially expressed proteins at the four time points were 128, 113, 106 and 127, respectively. Forty-nine proteins were identified simultaneously at two or more time points, of which 37 were up-regulated and 12 down-regulated. Bioinformatics analysis indicated that differentially expressed proteins are associated with post-translational modification, transcription, recombination and signal transduction pathways.

CONCLUSION: The protein changes in the process of rat hepatocarcinogenesis can be observed dynamically by iTRAQ combined with LC-ESI-MS/MS. Six proteins (peroxiredoxin-1, peroxiredoxin-2, thiosulfate sulfurtransferase, eukaryotic translation initiation factor 3 subunit b, alpha-2-HS-glycoprotein, and superoxide dismutase 1) are associated closely with hepatic fibrosis or hepatic carcinoma, and they may play critical roles in hepatocarcinogenesis.

Emerging role of Toll-like receptor 4 in hepatocellular carcinoma

Toll-like receptor (TLR) signaling has been implicated in inflammatory-related cancers. The upregulation of TLR signaling in hepatocellular carcinoma (HCC) suggests that it may play an essential role in the prognosis of chronic and inflammatory diseases that ultimately culminate in HCC. Here, we provide evidence about the involvement of the TLR pathway in the initiation, progression, and metastasis of HCC. The differential expression of TLR in epithelial cells has also been discussed. In particular, we emphasize the physiological role of TLR4 in the development and pathogenesis of HCC and propose novel and promising approaches for HCC therapeutics with the aid of TLR ligands.

Hepatitis C, innate immunity and alcohol: friends or foes?

Hepatitis C and alcohol are the most widespread causes of liver disease worldwide. Approximately 80% of patients with a history of hepatitis C and alcohol abuse develop chronic liver injury. Alcohol consumption in hepatitis C virus (HCV)-infected patients exacerbates liver disease leading to rapid progression of fibrosis, cirrhosis and even hepatocellular carcinoma. Hepatocytes are the main sites of HCV-infection and ethanol metabolism, both of which generate oxidative stress. Oxidative stress levels affect HCV replication and innate immunity, resulting in a greater susceptibility for HCV-infection and virus spread in the alcoholic patients. In this review paper, we analyze the effects of ethanol metabolism and other factors on HCV replication. In addition, we illustrate the mechanisms of how HCV hijacks innate immunity and how ethanol exposure regulates this process. We also clarify the effects of HCV and ethanol metabolism on interferon signaling-a crucial point for activation of anti-viral genes to protect cells from virus-and the role that HCV- and ethanol-induced impairments play in adaptive immunity which is necessary for recognition of virally-infected hepatocytes. In conclusion, ethanol exposure potentiates the suppressive effects of HCV on innate immunity, which activates viral spread in the liver and finally, leads to impairments in adaptive immunity. The dysregulation of immune response results in impaired elimination of HCV-infected cells, viral persistence, progressive liver damage and establishment of chronic infection that worsens the outcomes of chronic hepatitis C in alcoholic patients.

Hepatic toll-like receptor 4 expression is associated with portal inflammation and fibrosis in patients with NAFLD

BACKGROUND & AIMS

Notwithstanding evidences implicating the lipopolysaccharides (LPS)/toll-like receptor-4 (TLR4) axis in the pathogenesis of NAFLD, there are no studies aimed to characterize hepatic TLR4 expression in NAFLD patients. We aimed to analyse hepatic TLR4 expression and to verify its relationship with disease activity/evolution in NAFLD patients.

METHODS

Liver tissue from 74 patients with NAFLD and 12 controls was analysed by immunohistochemistry (IHC) for TLR4, α-smooth muscle actin (α-SMA) and cytokeratin-7. IHC for α-SMA was used to evaluate activation of fibrogenic cells (hepatic stellate cells and portal/septal myofibroblasts), that for cytokeratin-7 to count hepatic progenitor cells and bile ducts/ductules, and that for CD68, in a subgroup of 27 patients, for detecting macrophages. Serum LPS-binding protein (LBP), a sensitive marker of LPS activity, was determined in 36 patients and 32 controls.

RESULTS

As confirmed by double-labelling experiments, the highest level of TLR4 expression was observed in hepatic progenitor cells, biliary cells and portal/septal macrophages. TLR4-positive hepatic progenitor cells and bile ducts/ductules correlated with portal/interface inflammation, activity of fibrogenic cells and fibrosis (P < 0.001). Also the score of TLR4 positivity of porto-septal inflammatory infiltrate correlated with number of hepatic progenitor cells and bile ducts/ductules, activity of fibrogenic cells and fibrosis (P < 0.01). Serum LBP was increased in patients compared to controls (P < 0.001), and correlated with portal/interface inflammation, activity of portal/septal myofibroblasts and fibrosis (all P < 0.05).

CONCLUSIONS

TLR4 expression by regenerating and inflammatory cells at the porto-septal and interface level, favoured by increased LPS activity, is associated with activation of fibrogenic cells and the degree of fibrosis.

Gut-liver axis in alcoholic liver disease

Alcoholic liver disease (ALD) has been among the leading causes of cirrhosis and liver-related death worldwide for decades. Early discoveries in alcoholic liver disease identified increased levels of bacterial endotoxin in the portal circulation, suggesting a role for gut-derived toxins in ALD. Indeed, alcohol consumption can disrupt the intestinal epithelial barrier and result in increased gut permeability that increasingly is recognized as a major factor in ALD. Bacterial endotoxin, lipopolysaccharide, is a prototypic microbe-derived inflammatory signal that contributes to inflammation in ALD through activation of the Toll-like receptor 4. Recent studies also have shown that alcohol consumption is associated with alterations in the gut microbiome, and the dysbalance of pathogenic and commensal organisms in the intestinal microbiome may contribute to the abnormal gut-liver axis in ALD. Indeed, bacterial decontamination improves ALD both in human and animal models. This short review summarizes recent findings and highlights emerging trends in the gut-liver axis relevant to ALD.

Alcohol and HCV: implications for liver cancer

Liver cancers are one of the deadliest known malignancies which are increasingly becoming a major public health problem in both developed and developing countries. Overwhelming evidence suggests a strong role of infection with hepatitis B and C virus (HBV and HCV), alcohol abuse, as well as metabolic diseases such as obesity and diabetes either individually or synergistically to cause or exacerbate the development of liver cancers. Although numerous etiologic mechanisms for liver cancer development have been advanced and well characterized, the lack of definite curative treatments means that gaps in knowledge still exist in identifying key molecular mechanisms and pathways in the pathophysiology of liver cancers. Given the limited success with current therapies and preventive strategies against liver cancer, there is an urgent need to identify new therapeutic options for patients. Targeting HCV and or alcohol-induced signal transduction, or virus-host protein interactions may offer novel therapies for liver cancer. This review summarizes current knowledge on the mechanistic development of liver cancer associated with HCV infection and alcohol abuse as well as highlights potential novel therapeutic strategies.

Osteopontin deficiency does not prevent but promotes alcoholic neutrophilic hepatitis in mice

Alcoholic hepatitis (AH) is a distinct spectrum of alcoholic liver disease (ALD) with intense neutrophilic (polymorphonuclear; PMN) inflammation and high mortality. Although a recent study implicates osteopontin (SPP1) in AH, SPP1 is also shown to have protective effects on experimental ALD. To address this unsettled question, we examined the effects of SPP1 deficiency in male mice given 40% calories derived from ad libitum consumption of the Western diet high in cholesterol and saturated fat and the rest from intragastric feeding of alcohol diet without or with weekly alcohol binge. Weekly binge in this new hybrid feeding model shifts chronic ASH with macrophage inflammation and perisinusoidal and pericellular fibrosis to AH in 57% (15 of 26) of mice, accompanied by inductions of chemokines (Spp1, Cxcl1, and interleukin [Il]-17a), progenitor genes (Cd133, Cd24, Nanog, and epithelial cell adhesion molecule), PMN infiltration, and clinical features of AH, such as hypoalbuminemia, bilirubinemia, and splenomegaly. SPP1 deficiency does not reduce AH incidence and inductions of progenitor and fibrogenic genes, but rather enhances the Il-17a induction and PMN infiltration in some mice. Furthermore, in the absence of SPP1, chronic ASH mice without weekly binge begin to develop AH.

CONCLUSION

These results suggest that SPP1 has a protective, rather than causal, role for experimental AH reproduced in our model.

TLR4-dependent tumor-initiating stem cell-like cells (TICs) in alcohol-associated hepatocellular carcinogenesis

Alcohol abuse predisposes individuals to the development of hepatocellular carcinoma (HCC) and synergistically heightens the HCC risk in patients infected with hepatitis C virus (HCV). The mechanisms of this synergism have been elusive until our recent demonstration of the obligatory role of ectopically expressed TLR4 in 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 in a manner dependent on TLR4 and NANOG. TICs' tumor-initiating activity and chemoresistance are causally associated with inhibition of TGF-β tumor suppressor pathway due to NANOG-mediated expression of IGF2BP3 and YAP1. TLR4/NANOG activation causes 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.

New Approaches for Studying Alcoholic Liver Disease

Alcoholic liver disease (ALD) is major cause of chronic liver injury which results in liver fibrosis and cirrhosis. According to the surveillance report published by the National Institute on Alcohol Abuse and Alcoholism, liver cirrhosis is the 12th leading cause of death in the United States with 48 % of these deaths being attributed to excessive alcohol consumption. ALD includes a spectrum of disorders from simple steatosis to steatohepatitis, fibrosis, and hepatocellular carcinoma. Several mechanisms play a critical role in the pathogenesis of ALD. These include ethanol-induced oxidative stress and depletion of glutathione, pathological methionine metabolism, increased gut permeability and release of endotoxins into the portal blood, recruitment and activation of inflammatory cells including bone marrow-derived and liver resident macrophages (Kupffer cells). Chronic alcohol consumption results in liver damage and activation of hepatic stellate cells (HSCs) and myofibroblasts, leading to liver fibrosis. Here we discuss the current view on factors that are specific for different stages of ALD and those that regulate its progression, including cytokines and chemokines, alcohol-responsive intracellular signaling pathways, and transcriptional factors. We also review recent studies demonstrating that alcohol-mediated changes can be regulated on an epigenetic level, including microRNAs. Finally, we discuss the reversibility of liver fibrosis and inactivation of HSCs as a potential strategy for treating alcohol-induced liver damage.

Association between Toll-like receptor 4 and interleukin 17 gene polymorphisms and colorectal cancer susceptibility in Northeast China

Limited studies about the effects of TLR 4 and IL17 polymorphisms (SNPs) on the risk of colorectal cancer (CRC) have yielded inconsistent results. Totally, 601 CRC patients and 627 controls were enrolled. Unconditional logistic regression was used to estimate the association between tagSNPs and susceptibility of CRC and the interactions effects of gene and environment on the risk of CRC. IL17 rs6973569 AG and AG/AA genotypes significantly decreased the risk of CRC compared with GG genotype (ORadjusted=0.72, 95% CI 0.55-0.94 and ORadjusted=0.74, 95 % CI 0.57-0.97). The haplotype G-T-G-C-A-G accounting for the largest proportion haplotypes increased the risk of CRC (OR=1.27, 95 % CI 1.06-1.53). However, G-C-C-T-A-G and G-C-G-C-A-G haplotypes decreased the susceptibility of CRC. Synergistic interactions between TLR 4 rs1927911 CT/TT and higher pungent food intake as well as IL17 rs6973569 AG/AA genotypes and higher intake of sausage food (ORi=1.72, 95% CI 1.04-2.84 and ORi=3.38, 95% CI 1.28-8.91) on the risk of CRC were observed. IL17 rs6973569 SNP might be an independent factor of susceptibility to CRC. TLR 4 haplotype of G-T-G-C-A-G may increase risk of CRC. Higher intake of pungent and sausage food synergistically interacted with TLR 4 and IL17 SNPs on the risk of CRC.

Mechanisms of hepatocarcinogenesis in chronic hepatitis C

Infection with hepatitis C virus (HCV) is a major risk factor for hepatocellular carcinoma. The genetic changes that drive cancer development are heterogeneous and how chronic hepatitis C promotes the initiation of hepatocellular carcinoma is incompletely understood. Cancer typically arises in the setting of advanced fibrosis and/or cirrhosis where chronic immune-mediated inflammation over decades promotes hepatocyte turnover providing selective pressure that favors the malignant phenotype. As well as contributions of unresolved inflammation to carcinogenesis, evidence from transgenic mice with liver-specific expression of viral sequences suggests that some HCV-encoded proteins may directly promote cancer. Numerous in vitro studies suggest roles for HCV proteins in subversion of cellular pathways that normally act to suppress tumorigenesis. Here, we review the mechanisms by which persistent HCV infection might promote cancer in addition to the procarcinogenic effects of inflammatory liver disease.

The association of toll-like receptor 4 polymorphism with hepatitis C virus infection in Saudi Arabian patients

Hepatitis C virus (HCV) is a single stranded RNA virus. It affects millions of people worldwide and is considered as a leading cause of liver diseases including cirrhosis and hepatocellular carcinoma. A recent study reported that TLR4 gene polymorphisms are good prognostic predictors and are associated with protection from liver fibrosis among Caucasians. This study aims to investigate the implication of genetic polymorphisms of TLR4 gene on the HCV infection in Saudi Arabian patients. Two SNPs in the TLR4 gene, rs4986790 (A/G) and rs4986791 (C/T), were genotyped in 450 HCV patients and 600 uninfected controls. The association analysis confirmed that both SNPs showed a significant difference in their distribution between HCV-infected patients and uninfected control subjects (P < 0.0001; OR = 0.404, 95% CI = 0.281-0.581) and (P < 0.0001; OR = 0.298, 95% CI = 0.201-0.443), respectively. More importantly, haplotype analysis revealed that four haplotypes, AC, GT, GC, and AT (rs4986790, rs4986791), were significantly associated with HCV infection when compared with control subjects. One haplotype AC was more prominently found when chronic HCV-infected patients were compared with cirrhosis/HCC patients (frequency = 94.7% and P = 0.04). Both TLR4 SNPs under investigation were found to be significantly implicated with HCV-infection among Saudi Arabian population.

SALL4 immunoreactivity predicts prognosis in Western hepatocellular carcinoma patients but is a rare event: a study of 236 cases

Prognostic biomarkers that stratify patients with cancer are needed. Recent studies from Asia have implicated SALL4, a stem cell marker, as useful in identifying aggressive cases of hepatocellular carcinoma (HCC), and >50% of the cases tested had upregulation by microarray or dense immunoreactivity. Given the differences in predominant etiologic factors between the Asian and Western HCC, we sought to determine the prevalence of SALL4 immunoreactivity and its clinical relevance in Western HCC patients. We constructed tissue microarrays from 236 adult HCCs. Two cores each of tumor and nontumor tissue were included for each case. SALL4 immunohistochemistry was scored in a semiquantitative manner and the results correlated with recurrence-free and overall survival, in addition to standard demographics. Among the 236 cases, 165 (70.0%) were male. The median age was 59 years (range: 19 to 83 y). The majority (78.4%) of patients were white, followed by African American (15.7%), Asian (3.8%), Hispanic (1.7%), and Native American (0.4%). The majority of patients had hepatitis C (42.8%), followed by alcoholic liver disease and hepatitis B (both 8.9%), and nonalcoholic steatohepatitis (3.8%). SALL4 immunoreactivity was detected in a total of 3 cases (1.3%), and nonreactivity was validated on tissue sections from 73 cases. By univariate analysis, the SALL4-positive cases had significantly higher tumor grade (P=0.0251), more frequent lymphovascular invasion (P=0.0150), and shorter recurrence-free survival (7.90 vs. 57.54 mo; P=0.0115) and overall survival (7.90 vs. 64.87 mo; P=0.0018). Although SALL4 immunoreactivity in Western HCC is correlated with higher grade and poor prognosis, this is a rare event. Therefore, universal application of SALL4 as a biomarker for HCC should be performed with caution.

Contributions of metabolic dysregulation and inflammation to nonalcoholic steatohepatitis, hepatic fibrosis, and cancer

PURPOSE OF REVIEW

We review accumulating evidence that nonalcoholic steatohepatitis (NASH), a more advanced form of nonalcoholic fatty liver disease (NAFLD), predisposes patients to the risk of developing hepatocellular carcinoma (HCC), and we summarize recent advances in the elucidation of cancer-promoting pathways in NASH. We highlight the potential role of progenitor cells and hepatic stellate cells (HSCs) in promoting the early events that could culminate in cancer, as well as the emerging contribution of the gut-liver axis in promoting inflammation, senescence, and tumor growth in NASH and HCC. Finally, we review the role of bile acid receptors, vitamin D, and protective cellular pathways such as autophagy.

RECENT FINDINGS

Studies have recently uncovered roles for gut microbiota, bile acid receptors and vitamin D in regulating the progression from NAFLD to HCC. Intriguing findings linking senescence and autophagy in hepatic stellate cells to HCC have also been discovered, as well as a link between dysregulated progenitor cell regulation and HCC.

SUMMARY

NAFLD is the most common cause of chronic liver disease in the United States and Western Europe. The lack of definitive mechanisms underlying development of NASH among patients with NAFLD and its progression to HCC limit diagnosis and management, but new findings are paving the way for better biomarkers and therapies.

Interaction of PTPRO and TLR4 signaling in hepatocellular carcinoma

Protein tyrosine phosphatase receptor type O (PTPRO) has been identified as a tumor suppressor in a number of cancers including hepatocellular carcinoma (HCC). Toll-like receptor 4 (TLR4) plays diverse roles in HCC tumorigenesis and progression. The association between PTPRO and TLR4 signaling in HCC remains largely unknown. We aimed to clarify the interaction between PTPRO and TLR4 in HCC. Surprisingly, we found reduced and positive-related expression of TLR4 and PTPRO in 84 human HCC specimens. Increased TLR4 expression and activity was found in PTPRO-overexpressed HCC cells stimulated with lipopolysaccharide (LPS). The feedback regulation of PTPRO and TLR4 was dependent on nuclear factor-κB (NF-κB) activation, as suggested by NF-κB inhibition and luciferase reporter assay. Our study suggests that the effect of PTPRO on TLR4 signaling is dependent on NF-κB pathway, suggesting an interesting PTPRO/TLR4/NF-κB signaling feedback loop in HCC carcinogenesis and progression.

TLR3/4 signaling is mediated via the NFκB-CXCR4/7 pathway in human alcoholic hepatitis and non-alcoholic steatohepatitis which formed Mallory-Denk bodies

Activation of Toll-like receptor (TLR) signaling which stimulates inflammatory and proliferative pathways is the key element in the pathogenesis of Mallory-Denk bodies (MDBs) in mice fed DDC. However, little is known as to how TLR signaling is regulated in MDB formation during chronic liver disease development. The first systematic study of TLR signaling pathway transcript regulation in human archived formalin-fixed, paraffin-embedded (FFPE) liver biopsies with MDB formation is presented here. When compared to the activation of Toll-like signaling in alcoholic hepatitis (AH) and non-alcoholic steatohepatitis (NASH) patients, striking similarities and obvious differences were observed. Similar TLRs (TLR3 and TLR4, etc.), TLR downstream adaptors (MyD88 and TRIF, etc.) and transcript factors (NFκB and IRF7, etc.) were all upregulated in the patients' livers. MyD88, TLR3 and TLR4 were significantly induced in the livers of AH and NASH compared to normal subjects, while TRIF and IRF7 mRNA were only slightly upregulated in AH patients. This is a different pathway from the induction of the TLR4-MyD88-independent pathway in the AH and NASH patients with MDBs present. Importantly, chemokine receptor 4 and 7 (CXCR4/7) mRNAs were found to be induced in the patients livers in FAT10 positive hepatocytes. The CXCR7 pathway was significantly upregulated in patients with AH and the CXCR4 was markedly upregulated in patients with NASH, indicating that CXCR4/7 is crucial in liver MDB formation. This data constitutes the first demonstration of the upregulation of the MyD88-dependent TLR4/NFκB pathway in AH and NASH where MDBs formed, via the NFκB-CXCR4/7 pathway, and provides further insight into the mechanism of MDB formation in human liver diseases.