Hepatitis B virus X protein-mediated non-coding RNA aberrations in the development of human hepatocellular carcinoma

Hepatitis B Virus and microRNAs: A Bioinformatics Approach

In recent decades, microRNAs (miRNAs) have emerged as key regulators of gene expression, and the identification of viral miRNAs (v-miRNAs) within some viruses, including hepatitis B virus (HBV), has attracted significant attention. HBV infections often progress to chronic states (CHB) and may induce fibrosis/cirrhosis and hepatocellular carcinoma (HCC). The presence of HBV can dysregulate host miRNA expression, influencing several biological pathways, such as apoptosis, innate and immune response, viral replication, and pathogenesis. Consequently, miRNAs are considered a promising biomarker for diagnostic, prognostic, and treatment response. The dynamics of miRNAs during HBV infection are multifaceted, influenced by host variability and miRNA interactions. Given the ability of miRNAs to target multiple messenger RNA (mRNA), understanding the viral-host (human) interplay is complex but essential to develop novel clinical applications. Therefore, bioinformatics can help to analyze, identify, and interpret a vast amount of miRNA data. This review explores the bioinformatics tools available for viral and host miRNA research. Moreover, we introduce a brief overview focusing on the role of miRNAs during HBV infection. In this way, this review aims to help the selection of the most appropriate bioinformatics tools based on requirements and research goals.

Dysregulated microRNAs as a biomarker for diagnosis and prognosis of hepatitis B virus-associated hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a malignancy with a high incidence and fatality rate worldwide. Hepatitis B virus (HBV) infection is one of the most important risk factors for its occurrence and development. Early detection of HBV-associated HCC (HBV-HCC) can improve clinical decision-making and patient outcomes. Biomarkers are extremely helpful, not only for early diagnosis, but also for the development of therapeutics. MicroRNAs (miRNAs), a subset of non-coding RNAs approximately 22 nucleotides in length, have increasingly attracted scientists' attention due to their potential utility as biomarkers for cancer detection and therapy. HBV profoundly impacts the expression of miRNAs potentially involved in the development of hepatocarcinogenesis. In this review, we summarize the current progress on the role of miRNAs in the diagnosis and treatment of HBV-HCC. From a molecular standpoint, we discuss the mechanism by which HBV regulates miRNAs and investigate the exact effect of miRNAs on the promotion of HCC. In the near future, miRNA-based diagnostic, prognostic, and therapeutic applications will make their way into the clinical routine.

Lnc-AIFM2-1 promotes HBV immune escape by acting as a ceRNA for miR-330-3p to regulate CD244 expression

Chronic hepatitis B (CHB) virus infection is a major risk factor for cirrhosis and hepatocellular carcinoma (HCC). Hepatitis B virus (HBV) immune escape is regulated by the exhaustion of virus-specific CD8+ T cells, which is associated with abnormal expression of negative regulatory molecule CD244. However, the underlying mechanisms are unclear. To investigate the important roles of non-coding RNAs play in CD244 regulating HBV immune escape, we performed microarray analysis to determine the differential expression profiles of long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and mRNAs in patients with CHB and patients with spontaneous clearance of HBV. Competing endogenous RNA (ceRNA) was analyzed by bioinformatics methods and confirmed by the dual-luciferase reporter assay. Furthermore, gene silencing and overexpression experiments were used to further identify the roles of lncRNA and miRNA in HBV immune escape through CD244 regulation. The results showed that the expression of CD244 on the surface of CD8+ T cells was significantly increased in CHB patients and in the co-culture system of T cells and HBV-infected HepAD38 cells, which was accompanied by the reduction of miR-330-3p and the elevation of lnc-AIFM2-1. The down-regulated miR-330-3p induced the apoptosis of T cells by lifting the inhibition of CD244, which was reversed by miR-330-3p mimic or CD244-siRNA. Lnc-AIFM2-1 promotes the accumulation of CD244, which is mediated by decreased miR-330-3p, and then reduced the clearance ability of CD8+ T cells to HBV through regulated CD244 expression. And the injury in the ability of CD8+ T cells to clear HBV can be reversed by lnc-AIFM2-1-siRNA, miR-330-3p mimic, or CD244-siRNA. Collectively, our findings indicate that lnc-AIFM2-1 on CD244 by acting as a ceRNA of miR-330-3p contributes to HBV immune escape, which may provide novel insights into the roles of interaction networks among lncRNA, miRNA, and mRNA in HBV immune escape, highlighting potential applications of lnc-AIFM2-1 and CD244 for diagnosis and treatment in CHB.

Regulation of pleiotropic physiological roles of nitric oxide signaling

Nitric Oxide (NO) is a highly diffusible, ubiquitous signaling molecule and a free radical that is naturally synthesized by our body. The pleiotropic effects of NO in biological systems are due to its reactivity with different molecules, such as molecular oxygen (O₂), superoxide anion, DNA, lipids, and proteins. There are several contradictory findings in the literature pertaining to its role in oncology. NO is a Janus-faced molecule shown to have both tumor promoting and tumoricidal effects, which depend on its concentration, duration of exposure, and location. A high concentration is shown to have cytotoxic effects by triggering apoptosis, and at a low concentration, NO promotes angiogenesis, metastasis, and tumor progression. Upregulated NO synthesis has been implicated as a causal factor in several pathophysiological conditions including cancer. This dichotomous effect makes it highly challenging to discover its true potential in cancer biology. Understanding the mechanisms by which NO acts in different cancers helps to develop NO based therapeutic strategies for cancer treatment. This review addresses the physiological role of this molecule, with a focus on its bimodal action in various types of cancers.

Circular RNA circSFMBT2 downregulation by HBx promotes hepatocellular carcinoma metastasis via the miR-665/TIMP3 axis

Hepatitis B virus X protein (HBx) is considered as an oncogene in tumorigenesis and progression of hepatocellular carcinoma (HCC). In recent years, the important role of circular RNAs (circRNAs) in HCC has been increasingly demonstrated. However, the regulatory mechanisms of HBx on circRNAs remains largely unknown. In this study, we identified that a novel circRNA, circSFMBT2, was markedly downregulated by HBx. Low expression of circSFMBT2 was correlated with poor prognosis and vascular invasion. Functionally, overexpression of circSFMBT2 significantly inhibited HCC metastasis both in vitro and in vivo. The mechanism of circSFMBT2 was to as a sponge of miR-665, which is a negative regulator of tissue inhibitor of metalloproteinases 3 (TIMP3). However, HBx downregulated circSFMBT2 via the interaction with DExH-box helicase 9 (DHX9), which binds to flanking circRNA-forming introns. In conclusion, circSFMBT2, which is downregulated by HBx, acts as a tumor suppressor to inhibit tumor metastasis through the miR-665/TIMP3 axis. Our study suggests that circSFMBT2 could be a potential prognostic biomarker and therapeutic target for HCC.

Long noncoding RNAs in hepatitis B virus replication and oncogenesis

Several diverse long noncoding RNAs (lncRNAs) have been identified to be involved in hepatitis B virus (HBV) replication and oncogenesis, especially those dysregulated in HBV-related hepatocellular carcinoma (HCC). Most of these dysregulated lncRNAs are modulated by the HBV X protein. The regulatory mechanisms of some lncRNAs in HBV replication and oncogenesis have been characterized. Genetic polymorphisms of several lncRNAs affecting HBV replication or oncogenesis have also been studied. The prognosis of HCC remains poor. It is important to identify novel tumor markers for early diagnosis and find more therapeutic targets for effective treatments of HCC. Some dysregulated lncRNAs in HBV-related HCC may become biomarkers for early diagnosis and/or the therapeutic targets of HCC. This mini-review summarizes these findings briefly, focusing on recent developments.

Hepatitis B virus X protein mediated epigenetic alterations in the pathogenesis of hepatocellular carcinoma

Chronic hepatitis B virus (HBV) infection is a worldwide health problem. Hepatitis B virus X protein (HBx), a pleiotropic regulatory protein encoded by HBV, is necessary for the transcription of HBV covalently closed circular DNA (cccDNA) minichromosomes, and affects the epigenetic regulation of host cells. The epigenetic reprogramming of HBx on host cell genome is strongly involved in HBV-related HCC carcinogenesis. Here, we review the latest findings of the epigenetic regulation induced by HBx protein in hepatocellular carcinoma (HCC), including DNA methylation, histone modification and non-coding RNA expression. The influence of HBx on the epigenetic regulation of cccDNA is also summarized. In addition, preliminary studies of targeted drugs for epigenetic changes induced by HBx are also discussed. The exploration of epigenetic markers as potential targets will help to develop new prevention and/or treatment methods for HBx-related HCC.

Hepatitis B Virus-Associated Hepatocellular Carcinoma

Hepatitis B virus (HBV) is DNA-based virus, member of the Hepadnaviridae family, which can cause liver disease and increased risk of hepatocellular carcinoma (HCC) in infected individuals, replicating within the hepatocytes and interacting with several cellular proteins. Chronic hepatitis B can progressively lead to liver cirrhosis, which is an independent risk factor for HCC. Complications as liver decompensation or HCC impact the survival of HBV patients and concurrent HDV infection worsens the disease. The available data provide evidence that HBV infection is associated with the risk of developing HCC with or without an underlying liver cirrhosis, due to various direct and indirect mechanisms promoting hepatocarcinogenesis. The molecular profile of HBV-HCC is extensively and continuously under study, and it is the result of altered molecular pathways, which modify the microenvironment and lead to DNA damage. HBV produces the protein HBx, which has a central role in the oncogenetic process. Furthermore, the molecular profile of HBV-HCC was recently discerned from that of HDV-HCC, despite the obligatory dependence of HDV on HBV. Proper management of the underlying HBV-related liver disease is fundamental, including HCC surveillance, viral suppression, and application of adequate predictive models. When HBV-HCC occurs, liver function and HCC characteristics guide the physician among treatment strategies but always considering the viral etiology in the treatment choice.

Association between viral infection other than human papillomavirus and risk of esophageal carcinoma: a comprehensive meta-analysis of epidemiological studies

BACKGROUND

Infection with viruses such as human papillomavirus (HPV) is known to induce carcinomas, including esophageal carcinoma (EC). However, the possible role of viruses other than HPV in EC carcinogenesis is unclear in many studies. Here, we aimed to explore the association between infection with viruses other than HPV and EC risk by integrating existing studies of epidemiology in a meta-analysis.

METHODS

The PubMed, Web of Science, Cochrane Library and China National Knowledge Infrastructure databases were searched. The Newcastle-Ottawa scale was used to assess the quality of the included studies. Odds ratios (ORs) or relative risks (RRs) (with 95% confidence intervals [CIs]) were pooled to estimate the association between virus infection and risk of EC.

RESULTS

We included 31 eligible studies involving nine different viruses. Overall, an increased risk of EC was associated with hepatitis B virus (HBV) infection (OR = 1.19, 95%CI 1.01-1.36) and hepatitis C virus (HCV) infection (OR = 1.77, 95%CI 1.17-2.36), but not human immunodeficiency virus (HIV) infection, according to the current evidence. The evidence for an association with Epstein-Barr virus (EBV), herpes simplex virus 1 (HSV-1), JC virus (JCV), cytomegalovirus (CMV), human T-lymphotropic virus 1 (HTLV-1) or Merkel cell polyomavirus (MCPyV) infection was insufficient.

CONCLUSIONS

We confirmed the relationship between HBV and HCV infection and the risk of EC, but we found no association of EC risk with HIV and EBV infection. The roles of HSV-1, JCV, CMV, HTLV-1, and MCPyV were not clear because of the limited number of studies.

Treatment for Viral Hepatitis as Secondary Prevention for Hepatocellular Carcinoma

Chronic infections with either hepatitis B or C virus (HBV or HCV) are among the most common risk factors for developing hepatocellular carcinoma (HCC). The hepatocarcinogenic potential of these viruses is mediated through a wide range of mechanisms, including the induction of chronic inflammation and oxidative stress and the deregulation of cellular pathways by viral proteins. Over the last decade, effective anti-viral agents have made sustained viral suppression or cure a feasible treatment objective for most chronic HBV/HCV patients. Given the tumorigenic potential of HBV/HCV, it is no surprise that obtaining sustained viral suppression or eradication proves to be effective in preventing HCC. This review summarizes the mechanisms by which HCV and HBV exert their hepatocarcinogenic activity and describes in detail the efficacy of anti-HBV and anti-HCV therapies in terms of HCC prevention. Although these treatments significantly reduce the risk for HCC in patients with chronic viral hepatitis, this risk is not eliminated. Therefore, we evaluate potential strategies to improve these outcomes further and address some of the remaining controversies.

Circ-RNF13, as an oncogene, regulates malignant progression of HBV-associated hepatocellular carcinoma cells and HBV infection through ceRNA pathway of circ-RNF13/miR-424-5p/TGIF2

Circular RNA RNF13 (circ-RNF13; ID: hsa_circ_0067717) is newly identified to be abnormally upregulated in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) patients. However, its role and mechanism remain to be further annotated. First of all, real-time quantitative PCR (RT-qPCR) was utilized to examine RNA expression, and circ-RNF13 was upregulated in HBV-infected human HCC tissues and HBV-expressing cells (Huh7-HBV and Hep3B-HBV), accompanied with TGFβ-induced factor homeobox 2 (TGIF2) upregulation and microRNA (miR)-424-5p downregulation. Loss-of-functional experiments were performed using MTS assay, colony formation assay, flow cytometry, enzyme-linked immunosorbent assay, transwell assay, and xenograft tumor model. As a result, blocking circ-RNF13 enhanced the apoptosis rate of Huh7-HBV and Hep3B-HBV cells, but inhibited cell proliferation, colony formation, migration, and invasion in vitro, along with suppressed tumor growth in vivo. Besides, RT-qPCR data showed that HBV DNA copies and levels of hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were diminished by circ-RNF13 knockdown in Huh7-HBV and Hep3B-HBV cells. Mechanistically, circ-RNF13 and TGIF2 could directly interacting with miR-424-5p according to dual-luciferase reporter assay, suggesting that circ-RNF13 and TGIF2 served as competing endogenous RNAs (ceRNAs) for miR-424-5p. Functionally, overexpressing miR-424-5p mimicked and silencing miR-424-5p counteracted the effects of circ-RNF13 depletion in HBV-expressing HCC cells in vitro; TGIF2 restoration partially abrogated the role of miR-424-5p upregulation. In conclusion, circ-RNF13 might sponge miR-424-5p to suppress HBV-associated HCC cells malignant progression and HBV infection by regulating TGIF2, providing a novel insight into the occurrence and treatment of HBV-associated HCC.

The Functions of Hepatitis B Virus Encoding Proteins: Viral Persistence and Liver Pathogenesis

About 250 million people worldwide are chronically infected with Hepatitis B virus (HBV), contributing to a large burden on public health. Despite the existence of vaccines and antiviral drugs to prevent infection and suppress viral replication respectively, chronic hepatitis B (CHB) cure remains a remote treatment goal. The viral persistence caused by HBV is account for the chronic infection which increases the risk for developing liver cirrhosis and hepatocellular carcinoma (HCC). HBV virion utilizes various strategies to escape surveillance of host immune system therefore enhancing its replication, while the precise mechanisms involved remain elusive. Accumulating evidence suggests that the proteins encoded by HBV (hepatitis B surface antigen, hepatitis B core antigen, hepatitis B envelope antigen, HBx and polymerase) play an important role in viral persistence and liver pathogenesis. This review summarizes the major findings in functions of HBV encoding proteins, illustrating how these proteins affect hepatocytes and the immune system, which may open new venues for CHB therapies.

Role of Virus-Induced Host Cell Epigenetic Changes in Cancer

The tumor viruses human T-lymphotropic virus 1 (HTLV-1), hepatitis C virus (HCV), Merkel cell polyomavirus (MCPyV), high-risk human papillomaviruses (HR-HPVs), Epstein-Barr virus (EBV), Kaposi’s sarcoma-associated herpes virus (KSHV) and hepatitis B virus (HBV) account for approximately 15% of all human cancers. Although the oncoproteins of these tumor viruses display no sequence similarity to one another, they use the same mechanisms to convey cancer hallmarks on the infected cell. Perturbed gene expression is one of the underlying mechanisms to induce cancer hallmarks. Epigenetic processes, including DNA methylation, histone modification and chromatin remodeling, microRNA, long noncoding RNA, and circular RNA affect gene expression without introducing changes in the DNA sequence. Increasing evidence demonstrates that oncoviruses cause epigenetic modifications, which play a pivotal role in carcinogenesis. In this review, recent advances in the role of host cell epigenetic changes in virus-induced cancers are summarized.

Role of Nitric Oxide in Gene Expression Regulation during Cancer: Epigenetic Modifications and Non-Coding RNAs

Nitric oxide (NO) has been identified and described as a dual mediator in cancer according to dose-, time- and compartment-dependent NO generation. The present review addresses the different epigenetic mechanisms, such as histone modifications and non-coding RNAs (ncRNAs), miRNA and lncRNA, which regulate directly or indirectly nitric oxide synthase (NOS) expression and NO production, impacting all hallmarks of the oncogenic process. Among lncRNA, HEIH and UCA1 develop their oncogenic functions by inhibiting their target miRNAs and consequently reversing the inhibition of NOS and promoting tumor proliferation. The connection between miRNAs and NO is also involved in two important features in cancer, such as the tumor microenvironment that includes key cellular components such as tumor-associated macrophages (TAMs), cancer associated fibroblasts (CAFs) and cancer stem cells (CSCs).

TRERNA1 upregulation mediated by HBx promotes sorafenib resistance and cell proliferation in HCC via targeting NRAS by sponging miR-22-3p

Hepatocellular carcinoma (HCC) is among the most common malignancies and has an unfavorable prognosis. The hepatitis B virus-encoded X (HBx) protein is closely associated with hepatocarcinogenesis. Sorafenib is a unique targeted oral kinase inhibitor for advanced HCC. Long noncoding RNAs (lncRNAs) mediate HCC progression and therapeutic resistance by acting as competing endogenous RNAs (ceRNAs). However, the ceRNA regulatory mechanisms underlying sorafenib resistance in HBx-associated HCC remain largely unknown. In this study, we found that translation regulatory lncRNA 1 (TRERNA1) upregulation by HBx not only promoted HCC cell proliferation by regulating the cell cycle in vitro and in vivo but also correlated positively with poor prognosis in HCC. Importantly, TRERNA1 enhanced sorafenib resistance in HCC cells. RNA sequencing (RNA-seq) analysis indicated that NRAS proto-oncogene (NRAS) is a potential target of TRERNA1 that mediates aspects of hepatocellular carcinogenesis. TRERNA1 acts as a ceRNA to regulate NRAS expression by sponging microRNA (miR)-22-3p. In summary, we show that increased TRERNA1 expression induced by HBx reduces HCC cell sensitivity to sorafenib by activating the RAS/Raf/MEK/ERK signaling pathway. We reveal a novel regulatory mode by which the TRERNA1/miR-22-3p/NRAS axis mediates HCC progression and indicates that TRERNA1 might constitute a powerful tumor biomarker and therapeutic target in HCC.

3D human liver organoids: An in vitro platform to investigate HBV infection, replication and liver tumorigenesis

Hepatitis B Virus (HBV) infection is a leading cause of chronic liver cirrhosis and hepatocellular carcinoma (HCC) with an estimated 400 million people infected worldwide. The precise molecular mechanisms underlying HBV replication and tumorigenesis have remained largely uncharacterized due to the lack of a primary cell model to study HBV, a virus that exhibits stringent host species and cell-type specificity. Organoid technology has recently emerged as a powerful tool to investigate human diseases in a primary 3D cell-culture system that maintains the organisation and functionality of the tissue of origin. In this review, we describe the utilisation of human liver organoid platforms to study HBV. We first present the different categories of liver organoids and their demonstrated ability to support the complete HBV replication cycle. We then discuss the potential applications of liver organoids in investigating HBV infection and replication, related tumorigenesis and novel HBV-directed therapies. Liver organoids can be genetically modified, patient-derived, expanded and biobanked, thereby serving as a clinically-relevant, human, primary cell-derived platform to investigate HBV. Finally, we provide insights into the future applications of this powerful technology in the context of HBV-infection and HCC.

Role of ellagic acid for the prevention and treatment of liver diseases

Globally, one of the alarming problems is the prevalence and burden of liver diseases, which accounts for 2 million cases per year. Chronic liver aetiologies such as hepatitis infections, alcoholic or non-alcoholic liver disease, environmental agents, and drug-induced toxicity are invariably responsible for liver fibrosis progression to finally hepatocellular carcinoma. Current treatment options are unable to overwhelm and cure liver diseases. Emerging findings suggest researchers' interest in using evidence-based complementary medicine such as ellagic acid with extensive pharmacological properties. They include antioxidant, anti-inflammatory, anti-hyperlipidaemic, anti-viral, anti-angiogenic, and anticancer activity. The molecular functions elicited by ellagic acid include scavenging of free radicals, regulation of lipid metabolism, the prohibition of fibrogenesis response-mediating proteins, inhibits hepatic stellate cells and myofibroblasts, restrains hepatic viral replication, facilitates suppression of growth factors, regulates transcription factors, proinflammatory cytokines, augments the liver immune response, fosters apoptosis and inhibits cell proliferation in tumorigenic cells. This review will most notably focus on preclinical and clinical information based on currently available evidence to warrant ellagic acid's prospective role in preventing liver diseases.

Molecular mechanisms of viral hepatitis induced hepatocellular carcinoma

Chronic infection with viral hepatitis affects half a billion individuals worldwide and can lead to cirrhosis, cancer, and liver failure. Liver cancer is the third leading cause of cancer-associated mortality, of which hepatocellular carcinoma (HCC) represents 90% of all primary liver cancers. Solid tumors like HCC are complex and have heterogeneous tumor genomic profiles contributing to complexity in diagnosis and management. Chronic infection with hepatitis B virus (HBV), hepatitis delta virus (HDV), and hepatitis C virus (HCV) are the greatest etiological risk factors for HCC. Due to the significant role of chronic viral infection in HCC development, it is important to investigate direct (viral associated) and indirect (immune-associated) mechanisms involved in the pathogenesis of HCC. Common mechanisms used by HBV, HCV, and HDV that drive hepatocarcinogenesis include persistent liver inflammation with an impaired antiviral immune response, immune and viral protein-mediated oxidative stress, and deregulation of cellular signaling pathways by viral proteins. DNA integration to promote genome instability is a feature of HBV infection, and metabolic reprogramming leading to steatosis is driven by HCV infection. The current review aims to provide a brief overview of HBV, HCV and HDV molecular biology, and highlight specific viral-associated oncogenic mechanisms and common molecular pathways deregulated in HCC, and current as well as emerging treatments for HCC.

An updated literature review: how HBV X protein regulates the propagation of the HBV

Chronic HBV infection constitutes a burden on human beings and is closely associated with hepatocellular carcinoma. The propagation of the HBV is determined by many factors, and the HBV X protein (HBx) could have a significant influence on this. HBx is a regulatory protein that can directly or indirectly interact with many cellular proteins to affect both the propagation of the HBV and the activity of the host cells. In this review, we summarized the possible mechanisms by which HBx regulates HBV replication at transcriptional and post-transcriptional levels in various experimental systems.

The emerging role and significance of circular RNAs in viral infections and antiviral immune responses: possible implication as theranostic agents

Circular RNAs (circRNAs) are ubiquitously expressed, covalently closed rings, produced by pre-mRNA splicing in a reversed order during post-transcriptional processing. Circularity endows 3'-5'-linked circRNAs with stability and resistance to exonucleolytic degradation which raises the question whether circRNAs may be relevant as potential therapeutic targets or agents. High stability in biological systems is the most remarkable property and a major criterion for why circRNAs could be exploited for a range of RNA-centred medical applications. Even though various biological roles and regulatory functions of circRNAs have been reported, their in-depth study is challenging because of their circular structure and sequence-overlap with linear mRNA counterparts. Moreover, little is known about their role in viral infections and in antiviral immune responses. We believe that an in-depth and detailed understanding of circRNA mediated viral protein regulations will increase our knowledge of the biology of these novel molecules. In this review, we aimed to provide a comprehensive basis and overview on the biogenesis, significance and regulatory roles of circRNAs in the context of antiviral immune responses and viral infections including hepatitis C virus infection, hepatitis B virus infection, hepatitis delta virus infection, influenza A virus infection, Epstein-Barr virus infection, kaposi's sarcoma herpesvirus infection, human cytomegalovirus infection, herpes simplex virus infection, human immunodeficiency virus infection, porcine epidemic diarrhoea virus infection, ORF virus infection, avian leukosis virus infection, simian vacuolating virus 40 infection, transmissible gastroenteritis coronavirus infection, and bovine viral diarrhoea virus infection. We have also discussed the critical regulatory role of circRNAs in provoking antiviral immunity, providing evidence for implications as therapeutic agents and as diagnostic markers.

The Multiple Roles of Hepatitis B Virus X Protein (HBx) Dysregulated MicroRNA in Hepatitis B Virus-Associated Hepatocellular Carcinoma (HBV-HCC) and Immune Pathways

Currently, the treatment of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) [HBV-HCC] relies on blunt tools that are unable to offer effective therapy for later stage pathogenesis. The potential of miRNA to treat HBV-HCC offer a more targeted approach to managing this lethal carcinoma; however, the complexity of miRNA as an ancillary regulator of the immune system remains poorly understood. This review examines the overlapping roles of HBx-dysregulated miRNA in HBV-HCC and immune pathways and seeks to demonstrate that specific miRNA response in immune cells is not independent of their expression in hepatocytes. This interplay between the two pathways may provide us with the possibility of using candidate miRNA to manipulate this interaction as a potential therapeutic option.

Potential of the ellagic acid-derived gut microbiota metabolite - Urolithin A in gastrointestinal protection

Urolithin A (UA) is a metabolic compound generated during the biotransformation of ellagitannins by the intestinal bacteria. The physiologically relevant micromolar concentrations of UA, achieved in the plasma and gastrointestinal tract (GI) after consumption of its dietary precursors, have been revealed to offer GI protection. The health benefit has been demonstrated to be principally related to anticancer and anti-inflammatory effects. UA has been shown to possess the capability to regulate multiple tumor and inflammatory signaling pathways and to modulate enzyme activity, including those involved in carcinogen biotransformation and antioxidant defense. The purpose of this review is to gather evidence from both in vitro and in vivo studies showing the potential of UA in GI protection alongside suggested mechanisms by which UA can protect against cancer and inflammatory diseases of the digestive tract. The data presented herein, covering both studies on the pure compound and in vivo generated UA form its natural precursor, support the potential of this metabolite in treatment interventions against GI ailments.

Hepatitis B Virus-X Downregulates Expression of Selenium Binding Protein 1

Selenium binding protein 1 (SELENBP1) has been known to be reduced in various types cancer, and epigenetic change is shown to be likely to account for the reduction of SELNEBP1 expression. With cDNA microarray comparative analysis, we found that SELENBP1 is markedly decreased in hepatitis B virus-X (HBx)-expressing cells. To clarify the effect of HBx on SELENBP1 expression, we compared the expression levels of SELENBP1 mRNA and protein by semi-quantitative RT-PCR, Northern blot, and Western blot. As expected, SELENBP1 expression was shown to be reduced in cells expressing HBx, and reporter gene analysis showed that the SELENBP1 promoter is repressed by HBx. In addition, the stepwise deletion of 5′ flanking promoter sequences resulted in a gradual decrease in basal promoter activity and inhibition of SELENBP1 expression by HBx. Moreover, immunohistochemistry on tissue microarrays containing 60 pairs of human liver tissue showed decreased intensity of SELENBP1 in tumor tissues as compared with their matched non-tumor liver tissues. Taken together, our findings suggest that inhibition of SELENBP1 expression by HBx might act as one of the causes in the development of hepatocellular carcinoma caused by HBV infection.

Assessment of miR-212 and Other Biomarkers in the Diagnosis and Treatment of HBV-infection-related Liver Diseases

OBJECTIVES

Our study aims to detect the sensitivity of the new biomarker miR-212 existing in serum exosomes along with other hepatocellular carcinoma biomarkers such as AFP (alpha-fetoprotein), CA125 (carbohydrate antigen-ca125), and Hbx protein in the diagnosis of HBV-related liver diseases. We also aim to study the roles of these biomarkers in the progression of chronic hepatitis B and provide scientific data to show the clinical value of these biomarkers.

METHODS

We selected 200 patients with HBV-infection (58 cases of chronic hepatitis B, 47 cases of hepatocellular carcinoma, 30 cases of compensatory phase cirrhosis, and 65 cases of decompensatory phase cirrhosis), 31 patients with primary liver cancer without HBV infection, and 70 healthy individuals as the control group. The expression level of serum AFP and CA125 was detected with electrochemiluminescence immunoassay. The expression level of the Hbx protein was detected with ELISA. Meanwhile, the expression level of miR-212 in serum was analyzed with RT-qPCR. We collected patients' clinical information following the Child-Pugh classification and MELD score criterion, and statistical analysis was made between the expression level of miR-212 and the collected clinical indexes. Lastly, we predicted the target genes of the miR-212 and its functions using bioinformatics methods such as cluster analysis and survival prediction.

RESULTS

Compared to the control group, the expression level of miR-212 in HBV infected patients was remarkably increased (P<0.05), especially between the HBV-infection Hepatocellular carcinoma group and the non-HBVinfection liver cancer group (P<0.05). The expression of miR-212 was increased in patients' Child-Pugh classification, MELD score, and TNM staging. Moreover, the sensitivity and specificity of miR-212 were superior to AFP, CA125, and HBx protein.

CONCLUSION

There is a linear relationship between disease progression and expression level of miR-212 in the serum of HBV infected patients. This demonstrates that miR-212 plays a significant role in liver diseases. miR-212 is expected to be a new biomarker used for the diagnosis and assessment of patients with HBV-infection-related liver diseases.

The Regulatory Role of MicroRNA in Hepatitis-B Virus-Associated Hepatocellular Carcinoma (HBV-HCC) Pathogenesis

The incidence and mortality of hepatitis B virus (HBV)-associated hepatocellular carcinoma (HBV-HCC) is an intractable public health problem in developing countries that is compounded by limited early detection and therapeutic options. Despite the early promise of utilizing the regulatory role of miRNA in liver cancer, this field remains largely in the work-in-progress phase. This exploratory review paper adopts a broad focus in order to collate evidence of the regulatory role of miRNA in each stage of the HBV-HCC continuum. This includes the regulatory role of miRNA in early HBV infection, chronic inflammation, fibrosis/cirrhosis, and the onset of HCC. The paper specifically investigates HBV dysregulated miRNA that influence the expression of the host/HBV genome in HBV-HCC pathogenesis and fully acknowledges that this does not cover the full spectrum of dysregulated miRNA. The sheer number of dysregulated miRNA in each phase support a hypothesis that future therapeutic interventions will need to consider incorporating multiple miRNA panels.

Association between gene methylation and HBV infection in hepatocellular carcinoma: A meta-analysis

Gene methylation is an epigenetic alteration in hepatocellular carcinoma (HCC), and hepatitis B virus (HBV) plays a crucial role in carcinogenesis of HCC. However, the association between gene methylation and HBV infection in HCC remains unclear. In our study, we conducted a comprehensive meta-analysis to evaluate the association. A total of 1,148 studies were initially retrieved from some literature database. After a four-step filtration, we obtained 69 case-control studies in this meta-analysis. Our results showed six genes (p16, RASSF1A, GSTP1, APC, p15 and SFRP1) in HBV-positive carcinoma tissues, one gene (GSTP1) in HBV-positive adjacent tissues and two gene (p16 and APC) in HBV-positive carcinoma serums, which were significantly hypermethylated. Subgroup meta-analysis by geographical populations revealed that GSTP1 methylation was significantly higher in HBV-positive carcinoma tissues in China and Japan. In addition, p16 and RASSF1A methylation was significantly higher in China but not in Japan. Our study indicated that HBV infection could induce DNA methylation in HCC and DNA methylation could lead to the development of HBV-related HCC.

lncRNA-D16366 Is a Potential Biomarker for Diagnosis and Prognosis of Hepatocellular Carcinoma

Background

Long non-coding RNAs (lncRTNAs) are a new focus in cancer research. Although lncRNAs have no protein coding capacity, they are important in epigenetics as well as in regulating gene expression, playing an important role in various cancers. In the current study, we investigated the roles of lncRNA-D16366 in hepatocellular carcinoma (HCC) and expected to find a new biomarker for early detection and prognosis of the disease.

Material/Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of lncRNA-D16366 in tissue and serum samples. The relationship between lncRNA-D16366 expression and clinicopathologic characteristics of patients with HCC was analyzed to estimate whether it was involved in malignancy development. Then, potential diagnostic and prognostic values were evaluated via receiver operating characteristic (ROC) curve, Kaplan-Meier and Cox regression analysis, respectively.

Results

lncRNA-D16366 was proved to be decreased in the tissues and serum among patients with HCC compared with the corresponding controls. Its expression was influenced by tumor size, HbsAg, portal vein tumor thrombus, Child-Pugh score, therapies, and neoplasm metastasis. It had high diagnostic value, with an AUC of 0.752, accompanied by a sensitivity of 65.5% and a specificity of 84.6%. In addition, it was related to the prognosis of HCC.

Conclusions

lncRNA-D16366 was decreased in HCC, and might be an independent diagnostic and prognostic indicator in the disease.

Interplay of Wnt β-catenin pathway and miRNAs in HBV pathogenesis leading to HCC

The prevalence of Hepatocellular carcinoma (HCC) has been identified world-wide. Plethora of factors including chronic infection of HBV/HCV has been characterized for the development of HCC. Although the onset and progression of HCC has been linked with awry of various signaling pathways but precise mechanism, still lies under the multitude layers of curiosity. HBV is spreading with insane speed throughout the world and has been found a main culprit in HCC development after regulating the several cellular pathways including Wnt/β-catenin, Raf/MAPK, Akt and affecting cell multiplication to genomic instability. The role of Wnt/FZD/β-catenin signaling pathway is centralized in liver functions and its anomalous activation leads to HCC development. β-catenin mainly plays a pivotal role in canonical pathway of the system. Altered mainly overexpression of β-catenin along its nuclear localization tunes the aberrations in liver functions and set disease progression. In the development of HCC, modulation of Wnt/FZD/β-catenin signaling pathway by HBV has been established. As HBV infects the cell it affects the miRNAs, the master regulators of cell. Previous studies showed the connection between HBV and cellular miRNAs. In the present review, we unveiled how HBV is deciphering the cellular miRNAs like miR-26a, miR-15a, miR-16-1, miR-148a, miR-132, miR-122, miR-34a, miR-21, miR-29a, miR-222 and miR-199a/b-3p to modulate the Wnt/FZD/β-catenin signaling pathway and develop HCC. These HBV mediated miRNAs may prove future therapeutic options to treat HBV-Wnt/FZD/β-catenin associated HCC.

HBV suppresses ZHX2 expression to promote proliferation of HCC through miR-155 activation

Initiation of hepatocellular carcinoma (HCC) by chronic hepatitis B virus (HBV) infection is a complex process that includes both oncogene activation and tumor suppressor inhibition. The HBV X (HBx) protein has an important and complex role in processes leading to HCC. We previously identified the mammalian Zinc fingers and homeoboxes 2 (ZHX2) gene as an HCC-associated tumor suppressor gene. In the present study, we investigated whether the oncogenic properties of HBV and, more specifically, HBx, involved ZHX2 silencing. Our data indicates that ZHX2 expression is significantly decreased in tumor tissues from HBV-positive HCC patients and livers from HBV transgenic mice. In vitro and in vivo studies confirmed that HBV-encoded proteins, particularly HBx, inhibits both the expression and tumor suppression properties of ZHX2. Further analyses identified miR-155, a well-known oncomiR in various cancers, as an important link between HBx and ZHX2 inhibition. Increased miR-155 levels were found in HBV-positive tumors, livers of HBV transgenic mice and HBx-overexpressing hepatoma cell lines. MiR-155 overexpression reduced ZHX2 levels via miR-155 seed sites in the ZHX2 3'UTR, whereas blocking miR-155 levels led to increased ZHX2 levels. Taken together, our data indicate that HCC-promoting properties of HBV may include ZHX2 silencing via a miR-155 dependent pathway and suggests a novel therapy for HBV-related HCC.

Micro-RNAs in hepatitis B virus-related chronic liver diseases and hepatocellular carcinoma

MicroRNAs (miRNAs) are small non-coding RNAs that modulate gene expression at the post-transcriptional level by affecting both the stability and translation of complementary mRNAs. Several studies have shown that miRNAs are important regulators in the conflicting efforts between the virus (to manipulate the host for its successful propagation) and the host (to inhibit the virus), culminating in either the elimination of the virus or its persistence. An increasing number of studies report a role of miRNAs in hepatitis B virus (HBV) replication and pathogenesis. In fact, HBV is able to modulate different host miRNAs, particularly through the transcriptional transactivator HBx protein and, conversely, different cellular miRNAs can regulate HBV gene expression and replication by a direct binding to HBV transcripts or indirectly targeting host factors. The present review will discuss the role of miRNAs in the pathogenesis of HBV-related diseases and their role as a biomarker in the management of patients with HBV-related disease and as therapeutic targets.

Natural History of Chronic Hepatitis B Virus Infection in Ahvaz City, Iran

Objective: A long persistent of Chronic Hepatitis B (CHB) infection may develop liver cirrhosis or hepatocellular carcinoma (HCC) and about one million people die due to HBV -related liver cancer and end-stage liver disease annually worldwide. The natural history of CHB phases comprises four phases: immune tolerant (HBeAg detectable and ALT (Alanine Transaminase) normal, HBeAg-positive immune active (HBeAg detectable, anti-HBe antibodies undetectable and ALT persistently elevated), HBeAg-negative immune active (HBeAg undetectable, anti-HBe antibodies present and ALT persistently elevated), inactive carrier (HBeAg undetectable, anti-HBe antibodies present and ALT normal). The evaluation of chronic hepatitis B phases is a crucial to manage the burden of disease and limit the development of associated complications, such as cirrhosis and hepatocellular carcinoma (HCC). Thus this study conducted to evaluate the natural history of HBV infection in patients with chronic HBV infection in Ahvaz city, Iran. Methods: In this study, 71 non-treated CHB individuals were recruited including 44 (62%) males and 27(38%) females. The sera were tested for HBV markers, HBsAg, HBcIgG, HBeAg, and HBeAb. ALT assay and HBV viral load were carried out for each CHB individual. Results: Based on the analysis of serological, ALT status and viral load, the results showed: immune tolerance 5(7%), eAg+ Immune Clearance 14(19.7%), eAg- Immune Clearance 29 (40.84%) and Inactive Carrier 23 (32.39%). The HBeAg seroconversion was observed in a male age 18 year. Conclusion: The results of the natural history of individuals with chronic hepatitis B phases CHB shows immune tolerance (7%), eAg+ Immune Clearance (19.7%), eAg- Immune Clearance (40.84%) and Inactive Carrier (32.39%). To prevent the consequence of CHB infection, an individual in immune tolerance phase should be tested periodically for ALT level, HBV markers, HBsAg, HBcIgG, HBeAg, HBeAb and HBV viral load. Then decision-making therapy can be applied for CHB patients at early stage of immune clearance.

Correlation of oxidative stress in patients with HBV-induced liver disease with HBV genotypes and drug resistance mutations

OBJECTIVE

This study aims to explore the correlation of oxidative stress (OxS) in patients with chronic hepatitis B (CHB) and the disease severity with HBV genotypes and drug resistance mutations.

METHODS

A total of 296 patients with CHB were enrolled into the study. PCR-reverse dot-blot hybridization was used to detect the HBV genotypes (B, C, and D) and the drug resistance-causing HBV mutant genes. In addition, the total oxidative stress (TOS) and total antioxidant status (TAS) were determined, and oxidative stress index (OSI) was calculated and compared.

RESULTS

Serum levels of TOS and OSI, the B/C ratio, and drug resistance mutation rate were increased along with the elevated disease severity degree (CHB<HBC<HCC) (P < 0.05), while the serum TAS level showed the opposite trend (though there was no statistical difference between patients at the CHB and HBC stages). Moreover, patients with drug resistance-causing HBV mutation had higher serum TOS and OSI levels, while lower serum TAS levels (P < 0.05), compared with patients without mutations. Furthermore, mutation site numbers were positively correlated with the disease severity degree (γ = 0.614, P < 0.001).

CONCLUSION

There is oxidative damage in patients with HBV-induced liver disease, and the damage degree is correlated with the HBV genotype and drug resistance mutation. Oxidative stress might be a useful indicator of the progression of HBV-induced liver disease in patients.

Immune Responses in the Liver

The liver is a key, frontline immune tissue. Ideally positioned to detect pathogens entering the body via the gut, the liver appears designed to detect, capture, and clear bacteria, viruses, and macromolecules. Containing the largest collection of phagocytic cells in the body, this organ is an important barrier between us and the outside world. Importantly, as portal blood also transports a large number of foreign but harmless molecules (e.g., food antigens), the liver's default immune status is anti-inflammatory or immunotolerant; however, under appropriate conditions, the liver is able to mount a rapid and robust immune response. This balance between immunity and tolerance is essential to liver function. Excessive inflammation in the absence of infection leads to sterile liver injury, tissue damage, and remodeling; insufficient immunity allows for chronic infection and cancer. Dynamic interactions between the numerous populations of immune cells in the liver are key to maintaining this balance and overall tissue health.

Interference of Apoptosis by Hepatitis B Virus

Hepatitis B virus (HBV) causes liver diseases that have been a consistent problem for human health, leading to more than one million deaths every year worldwide. A large proportion of hepatocellular carcinoma (HCC) cases across the world are closely associated with chronic HBV infection. Apoptosis is a programmed cell death and is frequently altered in cancer development. HBV infection interferes with the apoptosis signaling to promote HCC progression and viral proliferation. The HBV-mediated alteration of apoptosis is achieved via interference with cellular signaling pathways and regulation of epigenetics. HBV X protein (HBX) plays a major role in the interference of apoptosis. There are conflicting reports on the HBV interference of apoptosis with the majority showing inhibition of and the rest reporting induction of apoptosis. In this review, we described recent studies on the mechanisms of the HBV interference with the apoptosis signaling during the virus infection and provided perspective.

A novel lncRNA uc.134 represses hepatocellular carcinoma progression by inhibiting CUL4A-mediated ubiquitination of LATS1

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide, and tumor recurrence and metastasis are major factors that contribute to the poor outcome of patients with HCC. Long noncoding RNAs (lncRNAs) are known to regulate different tumorigenic processes, and a growing body of evidence indicates that Hippo kinase signaling is inactivated in many cancers. However, the upstream lncRNA regulators of Hippo kinase signaling in HCC are poorly understood.

METHODS

Using a lncRNA microarray, we identified a novel lncRNA, uc.134, whose expression was significantly decreased in the highly aggressive HCC cell line HCCLM3 compared with MHCC97L cells. Furthermore, we evaluated uc.134 expression in clinical samples using in situ hybridization (ISH) and quantitative real-time polymerase chain reaction (qRT-PCR) analysis. The full-length transcript of uc.134 was confirmed using rapid amplification of cDNA ends (RACE) analyses. To investigate the biological function of uc.134, we performed gain-of-function and loss-of-function studies both in vitro and in vivo. The underlying mechanisms of uc.134 in HCC were investigated using RNA pulldown, RNA immunoprecipitation, ubiquitination assays, Western blotting, mRNA microarray analyses, and qRT-PCR analyses.

RESULTS

The ISH assay revealed that uc.134 expression was significantly decreased in 170 paraffin-embedded samples from patients with HCC compared with adjacent tissues and uc.134 expression directly correlated with patient prognosis. Furthermore, we defined a 1867-bp full-length transcript of uc.134 using 5'- and 3'-RACE analysis. The overexpression of uc.134 inhibited HCC cell proliferation, invasion, and metastasis in vitro and in vivo, whereas the knockdown of uc.134 produced the opposite results. Furthermore, we confirmed that uc.134 (1408-1867 nt) binds to CUL4A (592-759 aa region) and inhibits its nuclear export. Moreover, we demonstrated that uc.134 inhibits the CUL4A-mediated ubiquitination of LATS1 and increases YAP^S127 phosphorylation to silence the target genes of YAP. Finally, a positive correlation between uc.134, LATS1, and pYAP^S127 was confirmed in 90 paraffin-embedded samples by ISH and immunohistochemical staining.

CONCLUSIONS

Our study identifies that a novel lncRNA, uc.134, represses hepatocellular carcinoma progression by inhibiting the CUL4A-mediated ubiquitination of LATS1 and increasing YAP^S127 phosphorylation. The use of this lncRNA may offer a promising treatment approach by inhibiting YAP and activating Hippo kinase signaling.