Liver cancer-derived hepatitis C virus core proteins shift TGF-beta responses from tumor suppression to epithelial-mesenchymal transition

War or peace: Viruses and metastasis

Metastasis, the dissemination of malignant cells from a primary tumor to secondary sites, poses a catastrophic burden to cancer treatment and is the predominant cause of mortality in cancer patients. Metastasis as one of the main aspects of cancer progression could be strongly under the influence of viral infections. In fact, viruses have been central to modern cancer research and are associated with a great number of cancer cases. Viral-encoded elements are involved in modulating essential pathways or specific targets that are implicated in different stages of metastasis. Considering the continuous emergence of new viruses and the establishment of their contribution to cancer progression, the warfare between viruses and cancer appears to be endless. Here we aimed to review the critical mechanism and pathways involved in cancer metastasis and the influence of viral machinery and various routes that viruses adopt to manipulate those pathways for their benefit.

Management of intrahepatic and perihilar cholangiocarcinomas: Guidelines of the French Association for the Study of the Liver (AFEF)

Intrahepatic cholangiocarcinoma (iCCA) is the second most common malignant primary liver cancer. iCCA may develop on an underlying chronic liver disease and its incidence is growing in relation with the epidemics of obesity and metabolic diseases. In contrast, perihilar cholangiocarcinoma (pCCA) may follow a history of chronic inflammatory diseases of the biliary tract. The initial management of CCAs is often complex and requires multidisciplinary expertise. The French Association for the Study of the Liver wished to organize guidelines in order to summarize the best evidence available about several key points in iCCA and pCCA. These guidelines have been elaborated based on the level of evidence available in the literature and each recommendation has been analysed, discussed and voted by the panel of experts. They describe the epidemiology of CCA as well as how patients with iCCA or pCCA should be managed from diagnosis to treatment. The most recent developments of personalized medicine and use of targeted therapies are also highlighted.

HCV and HCC Tango-Deciphering the Intricate Dance of Disease: A Review Article

Hepatitis C virus (HCV) is a major cause of hepatocellular carcinoma (HCC) accounting for around one-third of all HCC cases. Prolonged inflammation in chronic hepatitis C (CHC), maintained through a variety of pro- and anti-inflammatory mediators, is one of the aspects of carcinogenesis, followed by mitochondrial dysfunction and oxidative stress. Immune response dysfunction including the innate and adaptive immunity also plays a role in the development, as well as in the recurrence of HCC after treatment. Some of the tumor suppressor genes inhibited by the HCV proteins are p53, p73, and retinoblastoma 1. Mutations in the telomerase reverse transcriptase promoter and the oncogene catenin beta 1 are two more important carcinogenic signaling pathways in HCC associated with HCV. Furthermore, in HCV-related HCC, numerous tumor suppressor and seven oncogenic genes are dysregulated by epigenetic changes. Epigenetic regulation of gene expression is considered as a lasting "epigenetic memory", suggesting that HCV-induced changes persist and are associated with liver carcinogenesis even after cure. Epigenetic changes and immune response dysfunction are recognized targets for potential therapy of HCC.

Recent Updates on Viral Oncogenesis: Available Preventive and Therapeutic Entities

Human viral oncogenesis is a complex phenomenon and a major contributor to the global cancer burden. Several recent findings revealed cellular and molecular pathways that promote the development and initiation of malignancy when viruses cause an infection. Even, antiviral treatment has become an approach to eliminate the viral infections and prevent the activation of oncogenesis. Therefore, for a better understanding, the molecular pathogenesis of various oncogenic viruses like, hepatitis virus, human immunodeficiency viral (HIV), human papillomavirus (HPV), herpes simplex virus (HSV), and Epstein-Barr virus (EBV), could be explored, especially, to expand many potent antivirals that may escalate the apoptosis of infected malignant cells while sparing normal and healthy ones. Moreover, contemporary therapies, such as engineered antibodies antiviral agents targeting signaling pathways and cell biomarkers, could inhibit viral oncogenesis. This review elaborates the recent advancements in both natural and synthetic antivirals to control viral oncogenesis. The study also highlights the challenges and future perspectives of using antivirals in viral oncogenesis.

Integrated analysis to study the interplay between post-translational modifications (PTM) in hepatitis C virus proteins and hepatocellular carcinoma (HCC) development

Many PTMs dysregulation is known to be the major cause of many cancers including HCV induced HCC. PTMs of hepatitis C virus (HCV) regions NS3/4A, NS5A and NS5B are crucial for proper protein functions and replication that directly affect the generation of infectious virus particles and completion of its life cycle. In this study, we have performed comprehensive analysis of PTMs within HCV non-structural proteins (NS3/4A, NS5A and NS5B) through bioinformatics analysis to examine post-translational crosstalk between phosphorylation, palmitoylation, methylation, acetylation and ubiquitination sites in selected viral proteins. Our analysis has revealed many highly putative PTMs sites that are also conserved among major genotypes conferring the importance of these sites. We have also analysed viral 3D structures in their modified and unmodified forms to address extent and signatures of structural changes upon PTM. This study provides evidence that PTMs induce significant conformational changes and make viral proteins more stable. To find the potential role of PTMs in HCV induced HCC, docking analysis between selected viral proteins and p38-MAPK has been performed which also confirms their strong association with HCV induced HCC. The major findings proposed that PTMs at specific sites of HCV viral proteins could dysregulate specific pathways that cause the development of HCC.

Hepatocellular Carcinoma: Understanding the Inflammatory Implications of the Microbiome

Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related death worldwide. It is well known that repeated inflammatory insults in the liver can cause hepatic cellular injury that lead to cirrhosis and, ultimately, hepatocellular carcinoma. Furthermore, the microbiome has been implicated in multiple inflammatory conditions which predispose patients to malignancy. With this in mind, we explore the inflammatory implications of the microbiome on pathways that lead to HCC. We also focus on how an understanding of these underlying inflammatory principles lead to a more wholistic understanding of this deadly disease, as well as potential therapeutic implications.

Coordinated activation of TGF-β and BMP pathways promotes autophagy and limits liver injury after acetaminophen intoxication

Ligands of the transforming growth factor-β (TGF-β) superfamily, including TGF-βs, activins, and bone morphogenetic proteins (BMPs), have been implicated in hepatic development, homeostasis, and pathophysiology. We explored the mechanisms by which hepatocytes decode and integrate injury-induced signaling from TGF-βs and activins (TGF-β/Activin) and BMPs. We mapped the spatiotemporal patterns of pathway activation during liver injury induced by acetaminophen (APAP) in dual reporter mice carrying a fluorescent reporter of TGF-β/Activin signaling and a fluorescent reporter of BMP signaling. APAP intoxication induced the expression of both reporters in a zone of cells near areas of tissue damage, which showed an increase in autophagy and demarcated the borders between healthy and injured tissues. Inhibition of TGF-β superfamily signaling by overexpressing the inhibitor Smad7 exacerbated acute liver histopathology but eventually accelerated tissue recovery. Transcriptomic analysis identified autophagy as a process stimulated by TGF-β1 and BMP4 in hepatocytes, with Trp53inp2, which encodes a rate-limiting factor for autophagy initiation, as the most highly induced autophagy-related gene. Collectively, these findings illustrate the functional interconnectivity of the TGF-β superfamily signaling system, implicate the coordinated activation of TGF-β/Activin and BMP pathways in balancing tissue reparatory and regenerative processes upon APAP-induced hepatotoxicity, and highlight opportunities and potential risks associated with targeting this signaling system for treating hepatic diseases.

Impact of HCV Infection on Hepatocyte Polarity and Plasticity

The hepatitis C virus (HCV) is an oncogenic virus that alters the cell polarization machinery in order to enter the hepatocyte and replicate. While these alterations are relatively well defined, their consequences in the evolution of the disease remain poorly documented. Since 2012, HCV infection can be effectively cured with the advent of direct acting antivirals (DAA). Nevertheless, patients cured of their HCV infection still have a high risk of developing hepatocellular carcinoma (HCC). Importantly, it has been shown that some of the deregulations induced by HCV are maintained despite a sustained virologic response (SVR), including the down-regulation of some hepatocyte functions such as bile acid metabolism, exemplifying cell dedifferentiation, and the up-regulation of the epithelial–mesenchymal transition (EMT). EMT is a process by which epithelial cells lose their differentiation and their specific polarity to acquire mesenchymal cell properties, including migration and extracellular matrix remodeling capabilities. Of note, epithelial cell polarity acts as a gatekeeper against EMT. Thus, it remains important to elucidate the mechanisms by which HCV alters polarity and promotes EMT that could participate in viral-induced hepatic carcinogenesis. In this review, we define the main steps involved in the polarization process of epithelial cells and recall the essential cellular actors involved. We also highlight the particularities of hepatocyte polarity, responsible for their unique morphology. We then focus on the alterations by HCV of epithelial cell polarity and the consequences of the transformation of hepatocytes involved in the carcinogenesis process.

Epithelial-Mesenchymal Transition Markers in HCVAssociated Hepatocellular Carcinoma: A Multivariate Follow Up Study

OBJECTIVE

Validated markers to predict recurrence after surgical resection of hepatocellular carcinoma (HCC) are needed. Little data is available regarding epithelial-mesenchymal transition (EMT) markers in HCC. The objective of this study was to investigate the expression of EMT markers and their correlation with clinicopathological variables and survival in hepatitis C virus (HCV)-associated HCC.

METHODS

This longitudinal study included 109 cases of HCV-associated HCC treated with surgical resection. Nine different EMT markers (vimentin, E-cadherin, N-cadherin, Stat3, Snail1, Slug, Twist1, Zeb1 and integrin α5) were evaluated on liver tissue from HCC cases. Twenty fresh HCC samples from the studied cases were used for gene expression of EMT markers by quantitative real time polymerase chain reaction (PCR).

RESULTS

EMT markers expression was 71%, 25%, 26%, 27%, 9%, 4%, 72%, 47%, 87% for vimentin, E-cadherin, N-cadherin, Stat3 snail1, slug, twist1, Zeb1 and integrin α5 respectively.  EMT mRNA in HCC tissues correlated with protein expression by 50-70%.  Vimentin was independent predictor of large tumor size (P=0.001), high risk of recurrence (HRR) (P=0.006) and shorter disease free survival (P=0.03) in multivariate analysis.  Reduced E-cadherin was a predictor of HRR (P=0.002).

CONCLUSION

Vimentin and E-cadherin were the most powerful prognostic EMT markers in HCV-associated HCC in prediction of recurrence.

Assessment of Plasma Vitronectin as Diagnostic and Prognostic Marker of Hepatocellular Carcinoma in Patients with Hepatitis C Virus Cirrhosis

Background: hepatitis C is an inflammatory liver disease caused by the hepatitis C infection (HCV), and without treatment, almost 50% will progress to liver cirrhosis. Hepatocellular carcinoma (HCC) is the most frequent type of primary liver cancer and the fourth leading cause of cancer-related mortality. Aim of the study: the objective of this study was to evaluate the serum level of vitronectin (VTN) compared to AFP and determine their role as diagnostic and prognostic markers of HCV-related liver diseases. Subject and Methods: this study involved 52 HCV patients from which 26 patients were cirrhotic, and 26 patients had HCC (on top of hepatitis C virus-related cirrhosis) plus 10 healthy people as a control group. It was carried out in Gastroenterology and Hepatology Unit, Internal Medicine Department, Zagazig University Hospitals, Egypt. All individuals in this study were subjected to physical examination, full history taking, liver function tests, assessment of serum levels of Vitronectin (VTN) and alpha-fetoprotein (AFP) before and after the intervention within three months. Results: serum level of vitronectin increased significantly in cirrhosis patients and HCC patients than controls (p = 0.0041), (p < 0.001), respectively, and in HCC than cirrhosis patients (p < 0.001). Significant positive correlations were observed between levels of serum VTN and AFP in all HCV patients as well as cirrhotic patients (p < 0.001, p = 0.011, respectively). On the contrary, VTN and AFP didn’t show a significant correlation in HCC patients’ group. Moreover, the median serum level of VTN decreased significantly after treatment in patients with HCC (p < 0.001). At cut-off 38.5 ng/mL for AFP it shows sensitivity 80.8%, specificity 76.9% to differentiate HCC from cirrhosis cases. While VTN shows 84.6% sensitivity, 96.2% specificity at cut-off 26.5 μg/mL. Regarding clinicopathological characteristics and VTN levels, half of patients were stage B, 63.9% had tumor size >3 cm, 84.6% had more than one focal lesion. Conclusions: these results may allow one to speculate a potential role of Vitronectin in diagnosis and prognosis of HCC on top of cirrhosis related to HCV infection in addition to AFP and US and CT.

GOLT1B Activation in Hepatitis C Virus-Infected Hepatocytes Links ER Trafficking and Viral Replication

Chronic hepatitis C carries a high risk of development of hepatocellular carcinoma (HCC), triggered by both direct and indirect effects of the virus. We examined cell-autonomous alterations in gene expression profiles associated with hepatitis C viral presence. Highly sensitive single molecule fluorescent in situ hybridization applied to frozen tissue sections of a hepatitis C patient allowed the delineation of clusters of infected hepatocytes. Laser microdissection followed by RNAseq analysis of hepatitis C virus (HCV)-positive and -negative regions from the tumoral and non-tumoral tissues from the same patient revealed HCV-related deregulation of expression of genes in the tumor and in the non-tumoral tissue. However, there was little overlap between both gene sets. Our interest in alterations that increase the probability of tumorigenesis prompted the examination of genes whose expression was increased by the virus in the non-transformed cells and whose level remained high in the tumor. This strategy led to the identification of a novel HCV target gene: GOLT1B, which encodes a protein involved in ER-Golgi trafficking. We further show that GOLT1B expression is induced during the unfolded protein response, that its presence is essential for efficient viral replication, and that its expression is correlated with poor outcome in HCC.

CEACAM6 promotes cholangiocarcinoma migration and invasion by inducing epithelial-mesenchymal transition through inhibition of the SRC/PI3K/AKT signaling pathway

The immunoglobulin superfamily member carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is overexpressed in a wide variety of human cancer types, and is associated with tumor invasion and migration. The aim of the present study was to determine the role of CEACAM6 in cholangiocarcinoma (CCA) invasion and migration in vitro. The results showed that CEACAM6 was highly expressed in CCA tissues, and that the expression level of CEACAM6 was negatively associated with the degree of differentiation of CCA. Silencing CEACAM6 inhibited cell viability, invasion and migration but promoted cell apoptosis in a human CCA cell line (RBE). In addition, CEACAM6 knockdown decreased the expression of an antiapoptotic protein (Bcl-2), an interstitial cell marker (N-cadherin), extracellular matrix proteins (MMP-2 and MMP-9), a transcription factor helix protein (Twist-related protein 1), an intermediate tumor cell scaffold marker (vimentin), a protein involved in tumor nutrient vascular formation (VEGFA) and a tumorigenesis factor (intercellular cell adhesion molecule-1), but increased the expression of pro-apoptotic proteins (Bax, and cleaved caspases-3, -8 and -9) and an epithelial cell marker protein (E-cadherin). Furthermore, CEACAM6-small interfering RNA reduced the expression of the SRC/PI3K/AKT signaling transduction pathway. Taken together, these results suggested that CEACAM6 may be an epithelial-mesenchymal transition biomarker and a potential therapeutic target in human CCA.

Strategies Targeting the Innate Immune Response for the Treatment of Hepatitis C Virus-Associated Liver Fibrosis

Direct-acting antivirals eliminate hepatitis C virus (HCV) in more than 95% of treated individuals and may abolish liver injury, arrest fibrogenesis, and reverse fibrosis and cirrhosis. However, liver regeneration is usually a slow process that is less effective in the late stages of fibrosis. What is more, fibrogenesis may prevail in patients with advanced cirrhosis, where it can progress to liver failure and hepatocellular carcinoma. Therefore, the development of antifibrotic drugs that halt and reverse fibrosis progression is urgently needed. Fibrosis occurs due to the repair process of damaged hepatic tissue, which eventually leads to scarring. The innate immune response against HCV is essential in the initiation and progression of liver fibrosis. HCV-infected hepatocytes and liver macrophages secrete proinflammatory cytokines and chemokines that promote the activation and differentiation of hepatic stellate cells (HSCs) to myofibroblasts that produce extracellular matrix (ECM) components. Prolonged ECM production by myofibroblasts due to chronic inflammation is essential to the development of fibrosis. While no antifibrotic therapy is approved to date, several drugs are being tested in phase 2 and phase 3 trials with promising results. This review discusses current state-of-the-art knowledge on treatments targeting the innate immune system to revert chronic hepatitis C-associated liver fibrosis. Agents that cause liver damage may vary (alcohol, virus infection, etc.), but fibrosis progression shows common patterns among them, including chronic inflammation and immune dysregulation, hepatocyte injury, HSC activation, and excessive ECM deposition. Therefore, mechanisms underlying these processes are promising targets for general antifibrotic therapies.

Key Players of Hepatic Fibrosis

Hepatic fibrosis is a complex mechanism defined by the net deposition of the extracellular matrix (ECM) owing to liver injury caused by multiple etiologies such as viral hepatitis and nonalcoholic fatty liver disease. Many cell types are implicated in liver fibrosis development and progression. In general, liver fibrosis starts with the recruitment of inflammatory immune cells to generate cytokines, growth factors, and other activator molecules. Such chemical mediators drive the hepatic stellate cells (HSCs) to activate the production of the ECM component. The activation of HSC is thus a crucial event in the fibrosis initiation, and a significant contributor to collagen deposition (specifically type I). This review explores the causes and mechanisms of hepatic fibrosis and focuses on the roles of key molecules involved in liver fibro genesis, some of which are potential targets for therapeutics to hamper liver fibro genesis.

Rewiring Host Signaling: Hepatitis C Virus in Liver Pathogenesis

Hepatitis C virus (HCV) is a major cause of liver disease including metabolic disease, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). HCV induces and promotes liver disease progression by perturbing a range of survival, proliferative, and metabolic pathways within the proinflammatory cellular microenvironment. The recent breakthrough in antiviral therapy using direct-acting antivirals (DAAs) can cure >90% of HCV patients. However, viral cure cannot fully eliminate the HCC risk, especially in patients with advanced liver disease or comorbidities. HCV induces an epigenetic viral footprint that promotes a pro-oncogenic hepatic signature, which persists after DAA cure. In this review, we summarize the main signaling pathways deregulated by HCV infection, with potential impact on liver pathogenesis. HCV-induced persistent signaling patterns may serve as biomarkers for the stratification of HCV-cured patients at high risk of developing HCC. Moreover, these signaling pathways are potential targets for novel chemopreventive strategies.

HEY2 acting as a co-repressor with smad3 and smad4 interferes with the response of TGF-beta in hepatocellular carcinoma

The HEY2 (hairy and enhancer of split-related with YRPW motif 2) is reported to play potential roles in tumorigenesis. However, the underlying mechanism in tumorigenesis is remain elusive. The present study aims to investigate the molecular mechanism of biological function of HEY2 in hepatocellular carcinoma (HCC). Dysfunction of the transforming growth factor-beta (TGF-β) pathway plays a critical role in HCC pathogenesis. Here, we identified HEY2 as a suppressor for TGF-β biological response. We demonstrated that HEY2 protein in tumor cytoplasm was up-regulated in HCC. Further, HEY2 overexpression inhibited TGF-β-induced growth arrest of HCC cells and inhibited TGF-β-induced downregulation of c-Myc, both in mRNA and in protein levels. While knockdown of HEY2, by small interfering RNA, was shown to enhance the TGF-β-mediated biological response of HCC cells. Moreover, HEY2 could form complexes with Smad3 and Smad4 and repress Smad3/Smad4 transcriptional activity. In conclusion, our findings indicate a novel role of HEY2 in mediating the TGF-β/Smad signaling pathway in HCC tumorigenesis.

Total HLA Class I Antigen Loss with the Downregulation of Antigen-Processing Machinery Components in Two Newly Established Sarcomatoid Hepatocellular Carcinoma Cell Lines

Limited information is currently available concerning HLA class I antigen abnormalities in sarcomatoid hepatocellular carcinoma (sHCC). Here, we have analyzed the growth characteristics and HLA class I antigen status of four sHCC cell lines (sHCC29, sHCC63, sHCC74, and SAR-HCV); the first three were newly established in this study. Among the four, sHCC29 showed the highest growth rate in vitro and tumorigenicity in NOD-SCID mice. Unlike sHCC74 and SAR-HCV, both sHCC29 and sHCC63 had no detectable surface HLA class I antigen expression, alongside undetected intracellular β₂-microglobulin (β₂m) and marked HLA class I heavy chain and selective antigen-processing machinery (APM) component downregulation. The loss of β₂m in sHCC29 and sHCC63 was caused by a >49 kb deletion across the B2M locus, while their downregulation of APM components was transcriptional, reversible by IFN-γ only in several components. β₂m was also undetected in the primary HCC lesions of the patients involved, indicating its in vivo relevance. We report for the first time HLA class I antigen loss with underlying B2M gene deficiency and APM defects in 50% (2 of 4) of the sHCC cell lines tested. These findings may have implications for a proper design of T cell immunotherapy for the treatment of sHCC patients.

Hepatitis C virus core protein modulates several signaling pathways involved in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer, and hepatitis C virus (HCV) infection plays a major role in HCC development. The molecular mechanisms by which HCV infection leads to HCC are varied. HCV core protein is an important risk factor in HCV-associated liver pathogenesis and can modulate several signaling pathways involved in cell cycle regulation, cell growth promotion, cell proliferation, apoptosis, oxidative stress and lipid metabolism. The dysregulation of signaling pathways such as transforming growth factor β (TGF-β), vascular endothelial growth factor (VEGF), Wnt/β-catenin (WNT), cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor α (PPARα) by HCV core protein is implicated in the development of HCC. Therefore, it has been suggested that this protein be considered a favorable target for further studies in the development of HCC. In addition, considering the axial role of these signaling pathways in HCC, they are considered druggable targets for cancer therapy. Therefore, using strategies to limit the dysregulation effects of core protein on these signaling pathways seems necessary to prevent HCV-related HCC.

Oncogenic Signaling Induced by HCV Infection

The liver is frequently exposed to toxins, metabolites, and oxidative stress, which can challenge organ function and genomic stability. Liver regeneration is therefore a highly regulated process involving several sequential signaling events. It is thus not surprising that individual oncogenic mutations in hepatocytes do not necessarily lead to cancer and that the genetic profiles of hepatocellular carcinomas (HCCs) are highly heterogeneous. Long-term infection with hepatitis C virus (HCV) creates an oncogenic environment by a combination of viral protein expression, persistent liver inflammation, oxidative stress, and chronically deregulated signaling events that cumulate as a tipping point for genetic stability. Although novel direct-acting antivirals (DAA)-based treatments efficiently eradicate HCV, the associated HCC risk cannot be fully eliminated by viral cure in patients with advanced liver disease. This suggests that HCV may persistently deregulate signaling pathways beyond viral cure and thereby continue to perturb cancer-relevant gene function. In this review, we summarize the current knowledge about oncogenic signaling pathways derailed by chronic HCV infection. This will not only help to understand the mechanisms of hepatocarcinogenesis but will also highlight potential chemopreventive strategies to help patients with a high-risk profile of developing HCC.

Upsetting the Balance: When Viruses Manipulate Cell Polarity Control

The central importance of cell polarity control is emphasized by the frequency with which it is targeted by many diverse viruses. It is clear that in targeting key polarity control proteins, viruses affect not only host cell polarity, but also influence many cellular processes, including transcription, replication, and innate and acquired immunity. Examination of the interactions of different virus proteins with the cell and its polarity controls during the virus life cycles, and in virally-induced cell transformation shows ever more clearly how intimately all cellular processes are linked to the control of cell polarity.

Corneal Epithelial Cells Exhibit Myeloid Characteristics and Present Antigen via MHC Class II

Purpose

To explore the impact of ocular surface insults on the immunomodulatory capacity and phenotype of corneal epithelial cells (CECs) with a focus on epithelial-mesenchymal transition (EMT).

Methods

Corneas were harvested from mice 6 days following scratch injury, ragweed pollen-induced allergy, or herpes simplex virus type 1 (HSV-1) infection and compared to healthy tissue controls. Corneas were enzymatically digested and CECs phenotypically characterized using flow cytometry. CECs were defined as epithelial cell adhesion molecule (EpCAM)-positive CD45-negative cells. CECs were assessed by PCR to evaluate EMT-associated transcripts. Recombinant HSV-1 and transgenic mice were utilized to investigate the role of vascular endothelial growth factor A (VEGFA) on the phenotype observed. The immunomodulatory potential of CECs was assessed in coculture assays with ovalbumin-specific CD4 T cells.

Results

Ectopic expression of classic "myeloid" antigens Ly6G, CCR2, and CX3CR1 was identified in CEC subsets from all groups with evidence supporting an underlying partial EMT event resulting from loss of cell-cell contacts. Corneal HSV-1 infection induced Ly6C expression and major histocompatibility complex (MHC)-II upregulation in CECs through a VEGFA-linked mechanism. These Ly6C+ MHC-II+ CECs were found to function as amateur antigen-presenting cells and induced CD4 T cell proliferation in vitro.

Conclusions

This study characterizes a novel immunomodulatory CEC phenotype with possible implications for immune privilege, chronic inflammation, and tissue fibrosis. Moreover, the identification of CECs masquerading with multiple "myeloid" antigens warrants careful evaluation of flow cytometry data involving corneal digests.

Viruses as key modulators of the TGF-β pathway; a double-edged sword involved in cancer

Transforming growth factor-β (TGF-β) signaling pathway is a key network in cell signaling that controls vital processes such as proliferation, differentiation, apoptosis, epithelial-mesenchymal transition, and migration, thus acting as a double-edged sword in normal development and diseases, in particular organ fibrosis, vascular disorders, and cancer. Early in tumorigenesis, the pathway exerts anti-tumor effects through suppressing cell cycle and inducing apoptosis, while during late stages, it functions as a tumor promoter by enhancing tumor invasiveness and metastasis. This signaling pathway can be perturbed by environmental and genetic factors such as microbial interference and mutation, respectively. In this way, the present review describes the modulation of the TGF-β pathway by oncogenic human viral pathogens and other viruses. The main mechanisms by which viruses interferes with TGF-β signaling seems to be through (1) the alteration of either TGF-β protein expression or activation, (2) the modulation of the TGF-β receptors or SMADs factors (by interfering with their levels and functions), (3) the alteration of none-SMAD pathways, and (4) indirect interaction with the pathway by the modulation of transcriptional co-activator/repressor and regulators of the pathway. Given the axial role of this pathway in tumorigenesis, it can be regarded as an attractive target for cancer therapy. Hence, further investigations on this subject may represent molecular targets among either TGF-β signaling molecules or viral factors for the treatment and management of viral infection consequences such as cancer.

Molecular basis of hepatocellular carcinoma induced by hepatitis C virus infection

Present study outlines a comprehensive view of published information about the underlying mechanisms operational for progression of chronic hepatitis C virus (HCV) infection to development of hepatocellular carcinoma (HCC). These reports are based on the results of animal experiments and human based studies. Although, the exact delineated mechanism is not yet established, there are evidences available to emphasize the involvement of HCV induced chronic inflammation, oxidative stress, insulin resistance, endoplasmic reticulum stress, hepato steatosis and liver fibrosis in the progression of HCV chronic disease to HCC. Persistent infection with replicating HCV not only initiates several liver alterations but also creates an environment for development of liver cancer. Various studies have reported that HCV acts both directly as well as indirectly in promoting this process. Whereas HCV related proteins, like HCV core, E1, E2, NS3 and NS5A, modulate signal pathways dysregulating cell cycle and cell metabolism, the chronic infection produces similar changes in an indirect way. HCV is an RNA virus and does not integrate with host genome and therefore, HCV induced hepatocarcinogenesis pursues a totally different mechanism causing imbalance between suppressors and proto-oncogenes and genomic integrity. However, the exact mechanism of HCC inducement still needs a full understanding of various steps involved in this process.

Sarcomatoid hepatocellular carcinoma (SHC): a case report

BACKGROUND

Sarcomatoid hepatocellular carcinoma (SHC) is a rare malignant hepatic tumor. Recurrent interventional therapies such as transcatheter arterial chemo-embolization (TACE), radiofrequency ablation (RFA), and percutaneous ethanol injection have been reported previously utilized in a majority of SHC cases. To date, the exact pathogenic mechanisms underlying sarcomatoid transformation of hepatocellular carcinoma (HCC) remain unknown.

CASE PRESENTATION

In this study, we report a 68-year-old female SHC patient admitted to our hospital due to discrete abdominal distention for more than 20 days. Abdominal computed tomography (CT) with tri-phase enhancement revealed portal vein tumor thrombi (PVTT) and a left hepatic lobe lesion measuring 110.0 mm × 160.0 mm. The patient subsequently underwent liver resection, after which pathological examination revealed proliferation of spindle-shaped SHC cells. A sarcomatoid, T4 stage carcinoma was eventually diagnosed. Forty-seven days after the operation, tri-phase enhanced CT detected extensive lesions in the liver, spleen, peritoneum, omentum majus, and mesentery, indicating SHC recurrence and metastases. Combination chemotherapy with pirarubicin and cisplatin was initiated for 1 cycle, but terminated due to resultant severe myelosuppression and medication intolerance. The patient was lost to therapy after 3 months of follow-up.

CONCLUSIONS

This case is unique because of hepatitis C virus infection. We should consider the possibility of this disease in patients with atypical clinical presentation.

Hepatic stellate cells as key target in liver fibrosis

Progressive liver fibrosis, induced by chronic viral and metabolic disorders, leads to more than one million deaths annually via development of cirrhosis, although no antifibrotic therapy has been approved to date. Transdifferentiation (or "activation") of hepatic stellate cells is the major cellular source of matrix protein-secreting myofibroblasts, the major driver of liver fibrogenesis. Paracrine signals from injured epithelial cells, fibrotic tissue microenvironment, immune and systemic metabolic dysregulation, enteric dysbiosis, and hepatitis viral products can directly or indirectly induce stellate cell activation. Dysregulated intracellular signaling, epigenetic changes, and cellular stress response represent candidate targets to deactivate stellate cells by inducing reversion to inactivated state, cellular senescence, apoptosis, and/or clearance by immune cells. Cell type- and target-specific pharmacological intervention to therapeutically induce the deactivation will enable more effective and less toxic precision antifibrotic therapies.

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.

Molecular mechanisms of hepatitis C virus-induced hepatocellular carcinoma

Hepatitis C virus (HCV) is a major leading cause of hepatocellular carcinoma (HCC). HCV-induced hepatocarcinogenesis is a multistep process resulting from a combination of pathway alterations that are either caused directly by viral factors or immune mediated as a consequence of a chronic state of inflammation. Host genetic variation is now emerging as an additional element that contribute to increase the risk of developing HCC. The advent of direct-acting antiviral agents foresees a rapid decline of HCC rate in HCV patients. However, a full understanding of the HCV-mediated tumourigenic process is required to elucidate if pro-oncogenic signatures may persist after virus clearance, and to identify novel tools for HCC prevention and therapy. In this review, we summarize the current knowledge of the molecular mechanisms responsible for HCV-induced hepatocarcinogenesis.

Mechanisms of HBV-induced hepatocellular carcinoma

Hepatitis B virus (HBV) contributes to hepatocellular carcinoma (HCC) development through direct and indirect mechanisms. HBV DNA integration into the host genome occurs at early steps of clonal tumor expansion and induces both genomic instability and direct insertional mutagenesis of diverse cancer-related genes. Prolonged expression of the viral regulatory protein HBx and/or altered versions of the preS/S envelope proteins dysregulates cell transcription and proliferation control and sensitizes liver cells to carcinogenic factors. Accumulation of preS1 large envelope proteins and/or preS2/S mutant proteins activates the unfold proteins response, that can contribute to hepatocyte transformation. Epigenetic changes targeting the expression of tumor suppressor genes occur early in the development of HCC. A major role is played by the HBV protein, HBx, which is recruited on cellular chromatin and modulates chromatin dynamics at specific gene loci. Compared with tumors associated with other risk factors, HBV-related tumors have a higher rate of chromosomal alterations, p53 inactivation by mutations and overexpression of fetal liver/hepatic progenitor cells genes. The WNT/β-catenin pathway is also often activated but HBV-related tumors display a low rate of activating β-catenin mutations. HBV-related HCCs may arise on non-cirrhotic livers, further supporting the notion that HBV plays a direct role in liver transformation by triggering both common and etiology specific oncogenic pathways in addition to stimulating the host immune response and driving liver chronic necro-inflammation.

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.

ESC reverses epithelial mesenchymal transition induced by transforming growth factor-β via inhibition of Smad signal pathway in HepG2 liver cancer cells

Background

Epithelial mesenchymal transition (EMT) mediated by TGF-β pays an important role in malignant tumor acquired abilities of migration and invasion. Our previous study showed that the extract of Stellera chamaejasme L. (ESC) was against proliferation of a variety of tumor cells, but there were no studies in the effects of ESC on EMT in tumor cells. In this study, TGF-β was adopted to induce EMT in HepG2 cells and the influence of ESC on EMT was observed.

Methods

MTT assay was used to observe the cell viability. Wound healing assay and transwell assay were used to observe the migration and invasion activities. Western blot and immunofluorescence methods were used to observe the expression of proteins.

Results

We found that HepG2 cells induced by TGF-β showed mesenchymal morphology, down-regulation of epithelial marker E-cadherin and up-regulation of mesenchymal marker Vimentin, indicating that TGF-β could mediate epithelial mesenchymal induction in HepG2 cells. ESC could reverse the mesenchymal morphology and regulate expressions of marker proteins in HepG2 induced by TGF-β and significantly inhibit TGF-β induced HepG2 cell migration and invasion. We further found that ESC could also significantly depress Smad2 phosphorylation and nuclear translocation, and ESC had coordination with SB432542, a specific inhibitor of TβRI kinases.

Conclusions

These results suggested that the ESC could reverse epithelial mesenchymal transition induced by TGF-β via inhibition Smad2 signaling pathway.

Hepatitis C virus core protein modulates pRb2/p130 expression in human hepatocellular carcinoma cell lines through promoter methylation

Background

Hepatitis C Virus (HCV) infection is associated with chronically evolving disease and development of hepatocellular carcinoma (HCC), albeit the mechanism of HCC induction by HCV is still controversial. The nucleocapsid (core) protein of HCV has been shown to be directly implicated in cellular transformation and immortalization, enhancing the effect of oncogenes and decreasing the one of tumor suppressor genes, as RB1 and its protein product pRB. With the aim of identifying novel molecular mechanisms of hepatocyte transformation by HCV, we examined the effect of HCV core protein on the expression of the whole Retinoblastoma (RB) family of tumor and growth suppressor factors, i.e. pRb, p107 and pRb2/p130.

Methods

We used a model system consisting of the HuH-7, HCV-free, human hepatocellular carcinoma cell line and of the HuH-7-CORE cells derived from the former and constitutively expressing the HCV core protein. We determined pRb, p107 and pRb2/p130 protein and mRNA amount of the respective genes RB1, RBL1 and RBL2, RBL2 promoter activity and methylation as well as DNA methyltransferase 1 (DNMT1) and 3b (DNMT3b) expression level. The effect of pRb2/p130 over-expression on the HCV core-expressing HuH-7-CORE cells was also evaluated.

Results

We found that the HCV core protein expression down-regulated pRb2/p130 protein and mRNA levels in HuH-7-CORE cells by inducing promoter hyper-methylation with the concomitant up-regulation of DNMT1 and DNMT3b expression. When pRb2/p130 expression was artificially re-established in HuH-7-CORE cells, cell cycle analysis outlined an accumulation in the G0/G1 phase, as expected.

Conclusions

HCV core appears indeed able to significantly down-regulate the expression and the function of two out of three RB family tumor and growth suppressor factors, i.e. pRb and pRb2/p130. The functional consequences at the level of cell cycle regulation, and possibly of more complex cell homeostatic processes, may represent a plausible molecular mechanism involved in liver transformation by HCV.

Hepatitis C virus core protein interacts with Snail and histone deacetylases to promote the metastasis of hepatocellular carcinoma

Downregulation of E-cadherin by the transcriptional repressor Snail is associated with acquisition of metastatic potential. Although hepatitis C virus (HCV) core protein has been implicated in hepatocarcinogenesis, it is unclear whether Snail is involved in HCV core-induced dysregulation of E-cadherin. Herein, we investigated the mechanism by which HCV core induces E-cadherin repression and the role of Snail in HCV core-mediated invasiveness and metastasis. We found that HCV infection, especially HCV core expression, effectively induced the epithelial-mesenchymal transition (EMT) in hepatoma cells by repressing E-cadherin. HCV core interacted with Snail and enhanced its binding to the E-box in the promoter region of E-cadherin, leading to decreased E-cadherin promoter activity. We found that HCV core, Snail, and the histone deacetylases HDAC1/HDAC2 formed a co-repressor complex at the E-cadherin promoter. Moreover, HCV core was shown to stabilize Snail through activation of the PI3K/Akt/GSK3β pathway. Silencing Snail expression restored E-cadherin expression and inhibited HCV core-promoted tumor growth and distant lung metastasis in vivo. Collectively, these results demonstrated that HCV core induced EMT by interacting with the transcriptional repressor complex Snail/HDACs at the E-cadherin promoter, which led to E-cadherin repression and increased invasiveness of hepatoma cells. These findings increase understanding of factors regulating metastasis in hepatoma and may ultimately lead to the development of novel treatment strategies for HCV-associated hepatocellular carcinoma.

Downregulation of miRNA-30c and miR-203a is associated with hepatitis C virus core protein-induced epithelial-mesenchymal transition in normal hepatocytes and hepatocellular carcinoma cells

Hepatitis C virus (HCV) Core protein has been demonstrated to induce epithelial-mesenchymal transition (EMT) and is associated with cancer progression of hepatocellular carcinoma (HCC). However, how the Core protein regulates EMT is still unclear. In this study, HCV Core protein was overexpressed by an adenovirus. The protein levels of EMT markers were measured by Western blot. The xenograft animal model was established by inoculation of HepG2 cells. Results showed that ectopic expression of HCV core protein induced EMT in L02 hepatocytes and HepG2 tumor cells by upregulating vimentin, Sanl1, and Snal2 expression and downregulating E-cadherin expression. Moreover, Core protein downregulated miR-30c and miR-203a levels in L02 and HepG2 cells, but artificial expression of miR-30c and miR-203a reversed Core protein-induced EMT. Further analysis showed that ectopic expression of HCV core protein stimulated cell proliferation, inhibited apoptosis, and increased cell migration, whereas artificial expression of miR-30c and miR-203a significantly reversed the role of Core protein in these cell functions in L02 and HepG2 cells. In the HepG2 xenograft tumor models, artificial expression of miR-30c and miR-203a inhibited EMT and tumor growth. Moreover, L02 cells overexpressing Core protein can form tumors in nude mice. In HCC patients, HCV infection significantly shortened patients' survival time, and loss of miR-30c and miR-203 expression correlated with poor survival. In conclusion, HCV core protein downregulates miR-30c and miR-203a expression, which results in activation of EMT in normal hepatocytes and HCC tumor cells. The Core protein-activated-EMT is involved in the carcinogenesis and progression of HCC. Loss of miR-30c and miR-203a expression is a marker for the poor prognosis of HCC.

Gamma-smooth muscle actin expression is associated with epithelial-mesenchymal transition and stem-like properties in hepatocellular carcinoma

BACKGROUND AND AIMS

The prognosis of hepatocellular carcinoma (HCC) is hampered by frequent tumour recurrence and metastases. Epithelial-Mesenchymal Transition (EMT) is now recognized as a key process in tumour invasion, metastasis and the generation of cancer initiating cells. The morphological identification of EMT in tumour samples from the expression of novel mesenchymal markers could provide relevant prognostic information and aid in understanding the metastatic process.

METHODS

The expression of Smooth Muscle Actins was studied using immunofluorescence and immunohistochemistry assays in cultured liver cells during an induced EMT process and in liver specimens from adult and paediatric HCC series.

RESULTS

We report here that in HCC cell lines treated with TGF-β and in HCC specimens, the expression of αSMA, a known mesenchymal marker of EMT, could never be detected. In addition, our in vitro studies identified the enteric form of SMA, γSMA, as being a marker of EMT. Moreover, this SMA isoform was expressed in 46% of 58 tumours from 42 adult HCC patients and in 90% of 16 tumours from 12 paediatric HCC patients. Interestingly, this expression was significantly correlated with poor tumour differentiation and progenitor cell features characterized by the expression of EpCAM and K19.

CONCLUSION

Taken together, our results support the conclusion that γSMA expression in HCC is strongly correlated with the EMT process, HCC aggressiveness and the identification of cancer stem cells. This correlation suggests that γSMA represents a novel and powerful marker to predict HCC progression.

Hepatitis C virus infection and the risk of intrahepatic cholangiocarcinoma and extrahepatic cholangiocarcinoma: evidence from a systematic review and meta-analysis of 16 case-control studies

Background

Studies investigating the association between hepatitis C virus (HCV) infections and the occurrence of cholangiocarcinoma (CCA), especially intrahepatic cholangiocarcinoma (ICC), have shown inconsistent findings. Although previous meta-analyses referred to HCV and CCA, they mainly focused on ICC rather than CCA or extrahepatic cholangiocarcinoma (ECC). Since then, relevant new studies have been published on the association between HCV and ICC. Since the different anatomic locations of CCA have distinct epidemiologic features and different risk factors, it is necessary to evaluate the relationship between HCV infection and ICC, ECC, and CCA.

Methods

Relevant studies were identified by searching PUBMED, EMBASE, and MEDLINE databases prior to 1 August 2013. Pooled risk estimates were calculated with random-effects models using STATA 11.0.

Results

A total of 16 case-control studies were included in the final analysis. Pooled risk estimates showed a statistically significant increasing risk of CCA (odds ratio (OR) = 5.44, 95% CI, 2.72 to 10.89). The pooled risk estimate of ICC (OR = 3.38, 95% CI, 2.72 to 4.21) was higher than that of ECC (OR = 1.75, 95% CI, 1.00 to 3.05). In a subgroup analysis, the pooled risk estimate of ICC in studies from North America was obviously higher than in Asia (6.48 versus 2.01). The Begg funnel plot and Egger test showed no evidence of publication bias.

Conclusions

HCV infection is associated with the increasing risk of CCA, especially ICC.

Hepatitis C virus core protein induces epithelial-mesenchymal transition in human hepatocytes by upregulating E12/E47 levels

Downregulation of E-cadherin is a hallmark of epithelial-mesenchymal transition (EMT), an essential component of cancer progression to more aggressive phenotypes characterized by tumor dedifferentiation, infiltration, and metastasis. However, the underlying mechanism for E-cadherin downregulation in hepatitis C virus (HCV)-associated hepatocellular carcinoma (HCC) is still unclear. In this study, we found that ectopic expression of HCV core protein or infection with HCV in human hepatocytes upregulated the levels of the transcriptional repressors, E12 and E47, resulting in inactivation of the E-cadherin promoter, containing E-box motifs, and subsequent repression of its expression. E12/E47 knock-down almost completely abolished the potential of HCV core protein to repress E-cadherin expression. HCV core protein inhibited ubiquitin-dependent proteasomal degradation of E12/E47 without affecting their expression at the transcriptional level. E12/E47 upregulation ultimately led to EMT in human hepatocytes, as demonstrated by morphological changes, altered expression levels of EMT markers, including E-cadherin, plakoglobin, and fibronectin, and increased capacity for cell detachment and migration. In conclusion, HCV core protein represses E-cadherin expression by upregulating E12/E47 levels to induce EMT in HCV-associated HCC.

Viruses in cancer cell plasticity: the role of hepatitis C virus in hepatocellular carcinoma

Viruses are considered as causative agents of a significant proportion of human cancers. While the very stringent criteria used for their classification probably lead to an underestimation, only six human viruses are currently classified as oncogenic. In this review we give a brief historical account of the discovery of oncogenic viruses and then analyse the mechanisms underlying the infectious causes of cancer. We discuss viral strategies that evolved to ensure virus propagation and spread can alter cellular homeostasis in a way that increases the probability of oncogenic transformation and acquisition of stem cell phenotype. We argue that a useful way of analysing the convergent characteristics of viral infection and cancer is to examine how viruses affect the so-called cancer hallmarks. This view of infectious origin of cancer is illustrated by examples from hepatitis C infection, which is associated with a high proportion of hepatocellular carcinoma.

Variations in DEPDC5 gene and its association with chronic hepatitis C virus infection in Saudi Arabia

Background

Variations at DEPDC5 gene have been recently reported as genetic markers associated with hepatocellular carcinoma (HCC) progression in chronic HCV-infected patients. This study was conducted to assess the association of DEPDC5 variants with advanced liver cirrhosis and HCC development among chronic HCV-infected patients in Saudi Arabian population.

Methods

Six-hundred and one HCV-infected patients were genotyped for DEPDC5 polymorphisms (rs1012068 and rs5998152), in comparison with 592 non-infected healthy control subjects. The allelic frequency and genotype distribution of both DEPDC5 polymorphisms were determined followed by haplotype frequency estimation and multiple logistic regression analysis.

Results

The frequency of the risk alleles of both rs1012068 and rs5998152 was shown to be more in healthy control subjects than in patients (p = 0.0001, OR = 0.704, CI = 0.591-0.839; p = 0.002, OR = 0.761, CI = 0. 0.639-0.907, respectively). Also, our results revealed that GT for SNP rs1012068 (OR =1.715; 95% CI 1.132-2.597; p = 0.0104) and CT for SNP rs5998152 (OR = 1.932; 95% CI 1.276-2.925; p = 0.0017) showed significant association with development of cirrhosis compared with the GG and CC genotypes, respectively. The data also revealed that subjects with the T allele of both SNPs appeared to have a lower susceptibility to HCV-related cirrhosis/HCC than those with the G allele of rs1012068 (p = 0.038, OR = 1.353, 95 % CI 1.017-1.800) and C allele of rs5998152 (p = 0.043, OR = 1.342, 95 % CI 1.010-1.784). Haplotype analysis showed that a combination of T-T alleles of rs1012068 and rs5998152 was significantly associated with liver cirrhosis (frequency = 71.3% and p = 0.027) and with cirrhosis/HCC (frequency = 71.4% and P = 0.045). Also, multiple logistic regression analysis showed that rs5998152 (OR = 2.844, 95% CI 1.333-6.069 and p = 0.007), rs1012068 (OR = 2.793, 95% CI 1.316-5.928 and p = 0.010), age (OR = 1.029, 95% CI 1.001-1.057 and p = 0.041) and HCV genotypes (OR = 0.247, 95% CI 0.097-0.630 and p = 0.003) were independently associated with chronicity of HCV infection.

Conclusion

Genetic variations in DEPDC5 gene region may influence HCV-associated liver cirrhosis and/or HCC development.

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.

Hepatitis C virus infection: establishment of chronicity and liver disease progression

Hepatitis C virus (HCV) often causes persistent infection, and is an important factor in the etiology of fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). There are no preventive or therapeutic vaccines available against HCV. Treatment strategies of HCV infection are likely to improve with recently discovered direct antiviral agents (DAAs). However, a proportion of patients still progress to liver failure and/or HCC despite having been cured of the infection. Thus, there is a need for early diagnosis and therapeutic modalities for HCV related end stage liver disease prevention. HCV genome does not integrate into its host genome, and has a predominantly cytoplasmic life cycle. Therefore, HCV mediated liver disease progression appears to involve indirect mechanisms from persistent infection of hepatocytes. Studying the underlying mechanisms of HCV mediated evasion of immune responses and liver disease progression is challenging due to the lack of a naturally susceptible small animal model. We and other investigators have used a number of experimental systems to investigate the mechanisms for establishment of chronic HCV infection and liver disease progression. HCV infection modulates immune systems. Further, HCV infection of primary human hepatocytes promotes growth, induces phenotypic changes, modulates epithelial mesenchymal transition (EMT) related genes, and generates tumor initiating stem-like cells (TISCs). HCV infection also modulates microRNAs (miRNAs), and influences growth by overriding normal death progression of primary human hepatocytes for disease pathogenesis. Understanding these ob-servations at the molecular level should aid in developing strategies for additional effective therapies against HCV mediated liver disease progression.

MEF2 transcription factors promotes EMT and invasiveness of hepatocellular carcinoma through TGF-β1 autoregulation circuitry

Invasion and metastasis is the main causes leading to the death of hepatocellular carcinoma (HCC) patients. However, the underlying mechanism is still to be explored. Transforming growth factor β1 (TGF-β1) is a stronger inducer of HCC cell invasion. However, the downstream effector of TGF-β1 that promotes HCC invasion is still unknown. In this study, we found that PI3K/Akt activation takes place following the stimulation of TGF-β1. The inhibition of PI3K/Akt activation abolished epithelial-mesenchymal transition (EMT) and invasion of HCC cells induced by TGF-β1. Myocyte enhancer factors 2 (MEF2) family proteins were found to be overexpressed in HCC cells under the treatment of TGF-β1 in a PI3K/Akt-dependent way. Silencing the expression of MEF2s was able to prevent the effect of TGF-β1 on HCC EMT and invasion. Unexpectedly, MEF2 proteins were able to promote the expression of TGF-β1 in HCC cells, suggesting the existence of regulatory circuitry consisting of TGF-β1, PI3K/Akt, and MEF2. A natural compound, oleanolic acid, was demonstrated to suppress the invasion and EMT of HCC cells by downregulating MEF2, showing that targeting this pathway is an effective therapeutic strategy for HCC invasion. We believe that our findings can contribute to better understanding of the involved mechanism of HCC invasion and the development of preventive and therapeutic strategy.

Production and pathogenicity of hepatitis C virus core gene products

Hepatitis C virus (HCV) is a major cause of chronic liver diseases, including steatosis, cirrhosis and hepatocellular carcinoma, and its infection is also associated with insulin resistance and type 2 diabetes mellitus. HCV, belonging to the Flaviviridae family, is a small enveloped virus whose positive-stranded RNA genome encoding a polyprotein. The HCV core protein is cleaved first at residue 191 by the host signal peptidase and further cleaved by the host signal peptide peptidase at about residue 177 to generate the mature core protein (a.a. 1-177) and the cleaved peptide (a.a. 178-191). Core protein could induce insulin resistance, steatosis and even hepatocellular carcinoma through various mechanisms. The peptide (a.a. 178-191) may play a role in the immune response. The polymorphism of this peptide is associated with the cellular lipid drop accumulation, contributing to steatosis development. In addition to the conventional open reading frame (ORF), in the +1 frame, an ORF overlaps with the core protein-coding sequence and encodes the alternative reading frame proteins (ARFP or core+1). ARFP/core+1/F protein could enhance hepatocyte growth and may regulate iron metabolism. In this review, we briefly summarized the current knowledge regarding the production of different core gene products and their roles in viral pathogenesis.

Epithelial-mesenchymal transition: molecular pathways of hepatitis viruses-induced hepatocellular carcinoma progression

Hepatocellular carcinoma is the fifth most common tumor and the third cause of death for cancer in the world. Among the main causative agents of this tumor is the chronic infection by hepatitis viruses B and C, which establish a context of chronic inflammation degenerating in fibrosis, cirrhosis, and, finally, cancer. Recent findings, however, indicate that hepatitis viruses are not only responsible for cancer onset but also for its progression towards metastasis. Indeed, they are able to promote epithelial-mesenchymal transition, a process of cellular reprogramming underlying tumor spread. In this manuscript, we review the currently known molecular mechanisms by which hepatitis viruses induce epithelial-mesenchymal transition and, thus, hepatocellular carcinoma progression.

Hepcidin and the iron enigma in HCV infection

An estimated 30-40% of patients with chronic hepatitis C have elevated serum iron, transferrin saturation, and ferritin levels. Clinical data suggest that iron is a co-morbidity factor for disease progression following HCV infection. Iron is essential for a number of fundamental metabolic processes in cells and organisms. Mammalian iron homeostasis is tightly regulated and this is maintained through the coordinated action of sensory and regulatory networks that modulate the expression of iron-related proteins at the transcriptional and/or posttranscriptional levels. Disturbances of iron homeostasis have been implicated in infectious disease pathogenesis. Viruses, similarly to other pathogens, can escape recognition by the immune system, but they need iron from their host to grow and spread. Hepcidin is a 25-aa peptide, present in human serum and urine and represents the key peptide hormone, which modulates iron homeostasis in the body. It is synthesized predominantly by hepatocytes and its mature form is released in circulation. In this review, we discuss recent advances in the exciting crosstalk of molecular mechanisms and cell signaling pathways by which iron and hepcidin production influences HCV-induced liver disease.

Interaction of Hepatitis C Viral Proteins with Cellular Oncoproteins in the Induction of Liver Cancer

Hepatitis C virus infection is a major health problem all over the world. A large proportion of patients infected by HCV develop liver cirrhosis or cancer. However, the mechanism(s) remain to be elucidated. Since HCV does not carry any known oncogene, it is thought that interaction between virally encoded proteins and host proteins is responsible for carcinogenesis. Many crucial interactions between HCV-encoded proteins and host proteins have been reported. In this review we focus on the interaction of viral proteins with important regulators of cell cycle—oncoproteins YB-1, p53, and cyclin D1—which play a major role in cell proliferation, apoptosis, DNA repair, and genomic stability. Genetic variants of HCV accumulate in patients and alter these interactions of host cell proteins. It is a battle between the virus and host and the final outcome depends on the winner; if the host succeeds in clearing the virus the patient may not develop serious liver diseases. On the other hand, if the virus dominates by evolving quasispecies which code for altered proteins that interact differently with host proteins, or induce mutations in host protooncogenes, then the patient may develop liver cirrhosis and/or liver cancer.