Hepatitis B virus X antigen promotes transforming growth factor-beta1 (TGF-beta1) activity by up-regulation of TGF-beta1 and down-regulation of alpha2-macroglobulin

Roles of TGF-β1 in Viral Infection during Pregnancy: Research Update and Perspectives

Transforming growth factor-beta 1 (TGF-β1) is a pleiotropic growth factor playing various roles in the human body including cell growth and development. More functions of TGF-β1 have been discovered, especially its roles in viral infection. TGF-β1 is abundant at the maternal-fetal interface during pregnancy and plays an important function in immune tolerance, an essential key factor for pregnancy success. It plays some critical roles in viral infection in pregnancy, such as its effects on the infection and replication of human cytomegalovirus in syncytiotrophoblasts. Interestingly, its role in the enhancement of Zika virus (ZIKV) infection and replication in first-trimester trophoblasts has recently been reported. The above up-to-date findings have opened one of the promising approaches to studying the mechanisms of viral infection during pregnancy with links to corresponding congenital syndromes. In this article, we review our current and recent advances in understanding the roles of TGF-β1 in viral infection. Our discussion focuses on viral infection during pregnancy, especially in the first trimester. We highlight the mutual roles of viral infection and TGF-β1 in specific contexts and possible functions of the Smad pathway in viral infection, with a special note on ZIKV infection. In addition, we discuss promising approaches to performing further studies on this topic.

Influence of C107R mutation from hepatitis B virus genotype H on in vitro hepatitis B surface antigen detection and IFN-β-1a treatment

Aim: Assess the in vitro effect of hepatitis B virus (HBV) genotype H (HBV/H) with the small surface HBV protein (HBs) C107R mutation on hepatitis B surface antigen (HBsAg) detection, TGFB1, CAT and IFNB1A expression, and the response to IFN-β-1a treatment. Methods: HBV/H wild-type and HBs  C107R variant replicons were constructed and transfected into hepatic stellate cells and/or Huh7 that were later treated with IFN-β-1a. HBsAg, HBV-DNA, pgRNA, TGFB1, CAT and IFNB1A expression was analyzed. 3D HBs structure from wild-type and C107R were foreseen by AlphaFold protein predictor, and IFN-β-1a antiviral effect was evaluated. Results: C107R mutation did not impact viral replication, but HBsAg serologic detection was affected. Wild-type and C107R similarly modified gene expression and responded to IFN-β-1a. Conclusion: C107R disrupts the Cys107/Cys138 disulfide bond and impairs HBsAg detection. Independently of the mutation, there were changes in TGFB1, CAT and IFNB1A expression, and a medium response to IFN-β-1a treatment compared with genotype A and C.

Hepatitis B x antigen (HBx) is an important therapeutic target in the pathogenesis of hepatocellular carcinoma

Hepatitis B virus (HBV) is a human pathogen that has infected an estimated two billion people worldwide. Despite the availability of highly efficacious vaccines, universal screening of the blood supply for virus, and potent direct acting anti-viral drugs, there are more than 250 million carriers of HBV who are at risk for the sequential development of hepatitis, fibrosis, cirrhosis and hepatocellular carcinoma (HCC). More than 800,000 deaths per year are attributed to chronic hepatitis B. Many different therapeutic approaches have been developed to block virus replication, and although effective, none are curative. These treatments have little or no impact upon the portions of integrated HBV DNA, which often encode the virus regulatory protein, HBx. Although given little attention, HBx is an important therapeutic target because it contributes importantly to (a) HBV replication, (b) in protecting infected cells from immune mediated destruction during chronic infection, and (c) in the development of HCC. Thus, the development of therapies targeting HBx, combined with other established therapies, will provide a functional cure that will target virus replication and further reduce or eliminate both the morbidity and mortality associated with chronic liver disease and HCC. Simultaneous targeting of all these characteristics underscores the importance of developing therapies against HBx.

Occult Hepatitis B Virus Infection: An Old Entity With Novel Clinical Involvements

Background

Occult hepatitis B infection (OBI) is recognized as a risk factor for cirrhosis and hepato-cellular carcinoma. However, OBI brings together a large spectrum of patients who might harbor different characteristics and prognosis.

Methods

We analyzed the databases of a university hospital in Paris to identify OBI among patients (n = 3966) concomitantly tested for hepatitis B virus (HBV) DNA and serology during a 7-year period. OBI patients were gathered into clinical entities according to their clinical records.

Results

Forty-seven OBIs were identified (1.2%). All patients had detectable anti-HBc, isolated (n = 26) or associated with anti-HBs (n = 21). The proportion of OBIs was 3.4% for patients with isolated anti-HBc and 4.2% for patients with both anti-HBc and anti-HBs. Four clinical categories of OBI patients were identified: patients with a passed HBV infection with HBs Ag clearance (group A, 23.4%); HBV-exposed patients receiving immunosuppressive therapy (group B, 29.8%); HIV/HBV-coinfected patients with therapy discontinuation (group C, 17%); HBV-exposed patients with severe liver conditions (group D, 29.8%). Significant follow-up was available for 32 patients, showing a more deleterious prognosis in group D patients, associated more with their underlying condition than the OBI status.

Conclusions

OBI is a heterogeneous condition with various clinical implications.

Somatic mutation profiling of liver and biliary cancer by targeted next generation sequencing

Liver and biliary cancers are highly lethal cancer types lacking effective treatments. The somatic mutations, particularly those with low mutant allele frequencies, in Chinese patients with liver and biliary cancer have not been profiled, and the frequency of patients benefiting from targeted therapy has not been studied. The present study evaluated the tumor tissues of 45 Chinese patients with hepatocellular carcinoma (HCC) and 12 Chinese patients with biliary tract cancer (BTC) by targeted next generation sequencing, with an average coverage of 639×, to identify alterations in 372 cancer-related genes. A total of 263 variants were identified in 139 genes, with 85.6% of these variants not previously reported in the Catalogue Of Somatic Mutations In Cancer database, and the mutation profile was different from the current datasets, including The Cancer Genome Atlas dataset and the National Cancer Center Japan (NCC_JP) dataset. Patients with hepatitis B virus (HBV) infection harbored more mutations than those without HBV infection, and the mutations in HBV carriers occurred preferentially in genes involved in vascular endothelial growth factor signaling pathways. Mutations in fibroblast growth factor and RAS signaling pathways were enriched in patients with cirrhosis, and alterations in interleukin and transforming growth factor signaling pathways were more frequently identified in individuals with abnormal bilirubin expression. Of all the patients, 7% exhibited variants in the target of sorafenib, and 42% harbored variants in the targets of drugs that have been approved to treat other types of cancer. These findings indicate diverse HCC/BTC variants patterns in different populations, and that the mutation load and patterns are correlated with clinical features. Further clinical studies are now warranted to evaluate the efficacies of other targeted drugs besides sorafenib in the treatment of patients with liver and biliary cancer.

Protective Effects of Moringa oleifera on HBV Genotypes C and H Transiently Transfected Huh7 Cells

Chronic hepatitis B infection treatment implicates a long-lasting treatment. M. oleifera extracts contain compounds with antiviral, antioxidant, and antifibrotic properties. In this study, the effect of M. oleifera was evaluated in Huh7 cells expressing either HBV genotypes C or H for the antiviral, antifibrotic, anti-inflammatory, and antioxidative responses. Huh7 cells were treated with an aqueous extract of M. oleifera (leaves) at doses of 0, 30, 45, or 60 μg/mL. The replicative virus and TGF-β1, CTGF, CAT, IFN-β1, and pgRNA expressions were measured by real time. HBsAg and IL-6 titers were determined by ELISA. CTGF, TGF-β1, IFN-β1, and pgRNA expressions decreased with M. oleifera treatment irrespective of the HBV genotype. HBsAg secretion in the supernatant of transfected Huh7 cells with both HBV genotypes was decreased regardless of the dose of M. oleifera. Similar effect was observed in proinflammatory cytokine IL-6, which had a tendency to decrease at 24 hours of treatment. Transfection with both HBV genotypes strongly decreased CAT expression, which is retrieved with M. oleifera treatment. M. oleifera treatment reduced fibrosis markers, IL-6, and HBsAg secretion in HBV genotypes C and H. However, at the level of replication, only HBV-DNA genotype C was slightly reduced with this treatment.

Update on occult hepatitis B virus infection

The event of mutations in the surface antigen gene of hepatitis B virus (HBV) results in undetectable hepatitis B surface antigen with positive/negative anti-hepatitis B core (anti-HBc) antibody status in serum and this phenomenon is named occult hepatitis B infection (OBI). The presence of anti-HBc antibody in serum is an important key for OBI tracking, although about 20% of OBI cases are negative for anti-HBc antibody. The diagnosis of OBI is mainly based on polymerase chain reaction (PCR) and real-time PCR assays. However, real-time PCR is a more reliable method than PCR. OBI is a great issue for the public health problem and a challenge for the clinical entity worldwide. The persistence of OBI may lead to the development of cirrhosis and hepatocellular carcinoma. With regard to OBI complications, the screening of HBV DNA by the highly sensitive molecular means should be implemented for: (1) patients with a previous history of chronic or acute HBV infection; (2) patients co-infected with hepatitis C virus/human immunodeficiency virus; (3) patients undergoing chemotherapy or anti-CD20 therapy; (4) recipients of organ transplant; (5) blood donors; (6) organ transplant donors; (7) thalassemia and hemophilia patients; (8) health care workers; (9) patients with liver related disease (cryptogenic); (10) hemodialysis patients; (11) patients undergoing lamivudine or interferon therapy; and (12) children in time of HBV vaccination especially in highly endemic areas of HBV. Active HBV vaccination should be implemented for the close relatives of patients who are negative for OBI markers. Thus, the goal of this review is to evaluate the rate of OBI with a focus on status of high risk groups in different regions of the world.

Risk Factors and Post-Resection Independent Predictive Score for the Recurrence of Hepatitis B-Related Hepatocellular Carcinoma

BACKGROUND

Independent risk factors associated with hepatitis B (HBV)-related hepatocellular carcinoma (HCC) after resection remains unknown. An accurate risk score for HCC recurrence is lacking.

METHODS

We prospectively followed up 200 patients who underwent liver resection for HBV-related HCC for at least 2 years. Demographic, biochemical, tumor, virological and anti-viral treatment factors were analyzed to identify independent risk factors associated with recurrence after resection and a risk score for HCC recurrence formulated.

RESULTS

Two hundred patients (80% male) who underwent liver resection for HBV-related HCC were recruited. The median time of recurrence was 184 weeks (IQR 52-207 weeks) for the entire cohort and 100 patients (50%) developed HCC recurrence. Stepwise Cox regression analysis identified that one-month post resection HBV DNA >20,000 IU/mL (p = 0.019; relative risk (RR) 1.67; 95% confidence interval (C.I.): 1.09-2.57), the presence of lymphovascular permeation (p<0.001; RR 2.69; 95% C.I.: 1.75-4.12), microsatellite lesions (p<0.001; RR 2.86; 95% C.I.: 1.82-4.51), and AFP >100ng/mL before resection (p = 0.021; RR 1.63; 95% C.I.: 1.08-2.47) were independently associated with HCC recurrence. Antiviral treatment before resection (p = 0.024; RR 0.1; 95% C.I.: 0.01-0.74) was independently associated with reduced risk of HCC recurrence. A post-resection independent predictive score (PRIPS) was derived and validated with sensitivity of 75.3% and 60.6% and specificity of 55.7% and 79.2%, to predict the 1- and 3-year risks for the HCC recurrence respectively with the hazard ratio of 2.71 (95% C.I.: 2.12-3.48; p<0.001). The AUC for the 1- and 3-year prediction were 0.675 (95% C.I.: 0.6-0.78) and 0.746 (95% C.I.: 0.69-0.82) respectively.

CONCLUSION

Several tumor, virological and biochemical factors were associated with a higher cumulative risk of HCC recurrence after resection. PRIPS was derived for more accurate risk assessment. Regardless of the HBV DNA level, antiviral treatment should be given to patients before resection to reduce the risk of recurrence.

Significance of viral status on prognosis of hepatitis B-related hepatocellular carcinoma after curative resection in East Asia

Tumor recurrence remains one major obstacle for further improving the prognosis of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients after curative liver resection. It has been widely reported that tumor size, positive surgical margin, macroscopic vascular invasion, tumor-node-metastasis stage and Edmondson's grade were significantly related to HCC recurrence. However, the association between HCC recurrence and important viral factors, including the HBV DNA levels, status of hepatitis B surface antigen and hepatitis B e-antigen, levels of cccDNA and hepatitis B core-related antigen, viral genotypes and specific viral sequence mutations remained controversial. Meanwhile, studies on the effect of postoperative adjuvant antiviral therapy on HCC recurrence have been relatively limited and have yielded conflicting results. Identification of certain viral risk factors for HCC recurrence and stratification of patient risk are very important to perform future surveillance programs. As a HBV hyperendemic region, the majority of HBV-related HCC patients develop in East Asia. In this article, we thus systematically reviewed the risk of important viral factors involved in recurrent carcinogenesis and the role of adjuvant antiviral therapy in preventing tumor recurrence in this area.

Transforming growth factor-β1 gene expression in hepatocellular carcinoma: a preliminary report

BACKGROUND AND STUDY AIMS

The transforming growth factor (TGF)-β signalling pathway plays a dual role in hepatocarcinogenesis. It has been recognised for its role as a tumour suppressor as well as a tumour promoter depending on the cellular context. The aim of this study was to investigate the clinical significance of serum TGF-β1 level and TGF-β1 messenger RNA (mRNA) in the peripheral blood of liver cirrhosis and hepatocellular carcinoma (HCC) patients as noninvasive biomarkers in diagnosing HCC.

PATIENTS AND METHODS

Twenty patients were allocated to each of the liver cirrhosis and HCC groups, in addition to 20 healthy volunteers. TGF-β1 gene expression in peripheral blood was quantitated using real-time polymerase chain reaction (PCR), while serum TGF-β1 was analysed using enzyme-linked immunosorbent assay (ELISA).

RESULTS

TGF-β1 gene expression was significantly lower in HCC patients (median 0.401 (0.241-0.699) fold change) than in liver cirrhosis patients (median 0.595 (0.464-0.816)) (p=0.042) and normal controls (median 1.00 (0.706-1.426) fold change) (p=0.001). TGF-β1 gene expression showed significant positive correlation with serum TGF-β1 (r=0.272, p=0.036) and significant negative correlation with alpha-fetoprotein (AFP) (r=-0.528, p=0.001). Receiver operating characteristic (ROC) analysis was conducted for TGF-β1 gene expression in comparison with AFP. The area under the curve for TGF-β1 gene expression was 0.688 (95% CI=0.517-0.858) (p=0.042) and AFP was 0.869 (95% CI=0.761-0.976) (p=0.001). The sensitivity and specificity of TGF-β1 gene expression were 65% and 75%, respectively, at a cutoff value of 0.462 fold change.

CONCLUSION

TGF-β1 gene expression in the peripheral blood may be used as a molecular marker for the diagnosis of HCC. Additional studies on a large-scale population are necessary to gain greater insight into the impact of TGF-β1 gene expression in the pathogenesis of HCC.

Bone tissue: Rebuilding and inflammation

In this review the author summarizes the knowledge related to structural elements of bone tissue. The process of bone reorganisation and knowledge about the special feature of bone metabolism in human are also discussed. It is noted that due to the reorganisation, there is a complete renewal of bone tissue in every 10 years, and this renewal lasts throughout the life. However, there are life periods when osteoclast activity is low, e.g. in childhood and the second decade of life when the gain of bone mass may be as much as 40% of the final bone mass. Overactivity of osteoclasts occurs at age 60 years in men and somewhat earlier in women. Reorganization of bone tissue is an elementary requirement for the physiological functions (locomotion, hemopoiesis, immune functions). The RANK-RANKL-osteoprotegerin axis plays an important role in the regulation of bone metabolism. Bone mass is dependent on osteocytes; osteoblasts are building up while osteoclasts are reabsorbing bone tissue. In this process transcription factors, hormone-like substances and a large number of cytokines are involved. In addition, the inflammatory process within the bone tissue as well as the defending, reparative inflammation and specific immune response are of great importance in bone reorganisation. This is particularly valid for α2-macroglobulin and transforming growth factor, although the exact role in bone reorganization has not been fully explored. It can be concluded that the elements, which participate in bone reorganization and in defending inflammatory and specific immunological processes, are essentially identical. Therefore, the existence of an osteo-immunological complex system has been emerged. Orv. Hetil., 2014, 155(40), 1575–1583.

The hepatitis B virus-associated tumor microenvironment in hepatocellular carcinoma

In contrast to a majority of cancer types, the initiation of hepatocellular carcinoma (HCC) is intimately associated with a chronically diseased liver tissue, with one of the most prevalent etiological factors being hepatitis B virus (HBV). Transformation of the liver in HBV-associated HCC often follows from or accompanies long-term symptoms of chronic hepatitis, inflammation and cirrhosis, and viral load is a strong predictor for both incidence and progression of HCC. Besides aiding in transformation, HBV plays a crucial role in modulating the accumulation and activation of both cellular components of the microenvironment, such as immune cells and fibroblasts, and non-cellular components of the microenvironment, such as cytokines and growth factors, markedly influencing disease progression and prognosis. This review will explore some of these components and mechanisms to demonstrate both underlying themes and the inherent complexity of these interacting systems in the initiation, progression, and metastasis of HBV-positive HCC.

Significance of viral status on recurrence of hepatitis B-related hepatocellular carcinoma after curative therapy: A meta-analysis

AIM

The impact of viral status on recurrence of hepatitis B-related hepatocellular carcinoma (HCC) after curative therapy remains controversial. This meta-analysis aimed to determine whether the presence of viral load, genotype, specific mutation and antiviral therapy influenced HCC recurrence after curative therapy.

METHODS

We performed a meta-analysis including 20 studies to assess the effect of viral status and antiviral therapy with nucleoside analog on recurrence of HCC after curative therapy. The pooled odds ratios (OR) were calculated using a random or fixed effects model. PUBMED, MEDLINE, EMBASE and the Cochrane Database were searched for articles published from 1990 to December 2012.

RESULTS

Our results showed that the presence of high viral load significantly increased overall HCC recurrence risk after curative therapy. Pooled data from four studies on the recurrence rate among patients with genotype C infection compared with genotype B showed an increased risk of recurrence. Basal core promoter (BCP) mutation was associated with a significant risk in the recurrence of HCC. The pooled estimate of treatment effect was significantly in favor of a preventive effectiveness of antiviral therapy.

CONCLUSION

The present study suggested that HCC patients with high viral load, genotype C and BCP mutation had a significantly higher risk of recurrence. Antiviral therapy has potential beneficial effects after the curative treatment of HCC in terms of tumor recurrence.

Significance of viral status on occurrence of hepatitis B-related hepatocellular carcinoma

Hepatitis B virus (HBV) infection remains a challenging global health problem, with more than 350 million people chronically infected and at risk of developing hepatocellular carcinoma (HCC). Interactions that occur among host, environmental, and viral factors determine the natural course and predict the prognosis of patients with chronic HBV infection. In the past decades, several important viral factors of predictive of HCC have been identified, such as high hepatitis B surface antigen level, seropositivity of hepatitis B e antigen, high viral load, viral genotype, and specific viral sequence mutations. Identification of certain viral risk factors for HCC development and stratification of patient risk are very important to perform future surveillance programs. In this article, we thus reviewed the risk of viral factors involved in hepatocarcinogenesis.

The roles of hepatitis B virus-encoded X protein in virus replication and the pathogenesis of chronic liver disease

INTRODUCTION

Hepatitis B virus (HBV) is a major cause of chronic liver disease (CLD) and hepatocellular carcinoma (HCC) worldwide. More than 350 million people are at risk for HCC, and with few treatment options available, therapeutic approaches to targets other than the virus polymerase will be needed. This review suggests that the HBV-encoded X protein, HBx, would be an outstanding target because it contributes to the biology and pathogenesis of HBV in three fundamental ways.

AREAS COVERED

First, HBx is a trans-activating protein that stimulates virus gene expression and replication, thereby promoting the development and persistence of the carrier state. Second, HBx partially blocks the development of immune responses that would otherwise clear the virus, and protects infected hepatocytes from immune-mediated destruction. Thus, HBx contributes to the development of CLD without virus clearance. Third, HBx alters patterns of host gene expression that make possible the emergence of HCC. The selected literature cited is from the National Library of Medicine (Pubmed and Medline).

EXPERT OPINION

Understanding the mechanisms, whereby HBx supports virus replication and promotes pathogenesis, suggests that HBx will be an important therapeutic target against both virus replication and CLD aimed at the chemoprevention of HCC.

Clinical significance of occult hepatitis B infection in progression of liver disease and carcinogenesis

Occult hepatitis B infection (OBI) is defined as long-lasting persistence of hepatitis B virus (HBV) DNA in the liver of patients with hepatitis B surface antigen (HBsAg)-negative status, with or without serological markers of previous exposure (antibodies to HBsAg and/or to hepatitis B core antigen). Over the past two decades, significant progress has been made in understanding OBI and its clinical implications. OBI as a cause of chronic liver disease in patients with HBsAg-negative status is becoming an important disease entity. In conditions of immunocompetence, OBI is inoffensive in itself and detection of HBV DNA in the liver does not always indicate active hepatitis. However, when other factors that cause liver damage, such as hepatitis C virus infection, obesity and alcohol abuse are present, the minimal lesions produced by the immunological response to OBI might worsen the clinical course of the underlying liver disease. Several lines of evidence suggest that OBI is associated with progression of liver fibrosis and the development of hepatocellular carcinoma in patients with chronic liver disease. The major interest in OBI is primarily associated with the growing, widely discussed evidence of its clinical impact. The aim of this review is to highlight recent data for OBI, with a major focus on disease progression or carcinogenesis in patients with chronic liver disease.

Posthepatectomy HBV reactivation in hepatitis B-related hepatocellular carcinoma influences postoperative survival in patients with preoperative low HBV-DNA levels

OBJECTIVE

This study aimed to clarify the incidence of hepatitis B virus (HBV) reactivation and its significance on long-term survival after partial hepatectomy in patients with HBV-related hepatocellular carcinoma (HCC), who had preoperative low HBV-DNA level of less than 2000 IU/mL.

BACKGROUND

HBV reactivation is a frequent complication of systemic chemotherapy in hepatitis B surface antigen-positive patients. Surgery and anesthesia result in a generalized state of immunosuppression in the immediate postoperative period. Data on HBV reactivation and its significance after partial hepatectomy are unclear.

PATIENTS AND METHODS

Consecutive patients from January 2006 to December 2007 were retrospectively studied.

RESULTS

HBV reactivation happened in 19.1% of patients in 1 year. There were 28 patients whose HBV reactivation was detected after the diagnosis of HCC recurrence. On multivariate analysis, hepatitis B e antigen (HBeAg) positivity, preoperative HBV-DNA above the lower limit of quantification (≥200 IU/mL), Ishak inflammation score of greater than 3, preoperative transarterial chemoembolization (TACE), operation time of more than 180 minutes, blood transfusion, and without prophylactic antiviral therapy were significantly associated with an increased risk of HBV reactivation. HBV reactivation negatively influenced postoperative hepatic functions. The posthepatectomy liver failure rate in patients with HBV reactivation was significantly higher than in those without reactivation (11.8% vs 6.4%; P = 0.002). The 3-year disease-free survival (DFS) rate and overall survival (OS) rates after resection in patients with HBV reactivation were significantly lower than those without reactivation (34.1% vs 46.0%; P = 0.009, and 51.6% vs 67.2%; P < 0.001, respectively). HBeAg positivity, detectable preoperative HBV-DNA level, high Ishak inflammation score, preoperative TACE, long operation time, and blood transfusion were independent risk factors for HBV reactivation, whereas prophylactic antiviral therapy was a protective factor. HBV reactivation, HBeAg positivity, HBV-DNA level of 200 IU/mL or more, tumor diameter greater than 5 cm, presence of satellite nodules, presence of portal vein tumor thrombus, blood transfusion, and resection margin less than 1.0 cm were independent risk factors for DFS. A HBV-DNA level of 200 IU/mL or more, an Ishak fibrosis score of 4 or greater, a tumor diameter greater than 5 cm, the presence of satellite nodules, the presence of portal vein tumor thrombus, a resection margin less than 1.0 cm, no prophylactic antiviral therapy, and HBV reactivation were independent risk factors for OS.

CONCLUSIONS

HBV reactivation was common after partial hepatectomy for HBV-related HCC with a preoperative low HBV-DNA level of less than 2000 IU/mL. Routine prophylactic antiviral treatment should be given before partial hepatectomy.

[Macroglobulin signaling system]

This review will focus on the systematization of knowledge about structure of macroglobulin signaling system, which includes macroglobulin family proteins (alpha-2-macroglobulin, alpha-2-glycoprotein, pregnancy associated plasma protein A), their receptors (LRP, grp78), ligands (proteinases, cytokines, hormones, lipids, et al.) transforming and transcriptional factors for regulation of macroglobulins synthesis. After reviewing the functions of macroglobulin signaling system, and mechanisms of their realization, we discuss the complex and significant role of this system in different physiological and pathological processes.

TGF-β1 down-regulation of NKG2D/DAP10 and 2B4/SAP expression on human NK cells contributes to HBV persistence

The mechanism underlying persistent hepatitis B virus (HBV) infection remains unclear. We investigated the role of innate immune responses to persistent HBV infection in 154 HBV-infected patients and 95 healthy controls. The expression of NKG2D- and 2B4-activating receptors on NK cells was significantly decreased, and moreover, the expression of DAP10 and SAP, the intracellular adaptor proteins of NKG2D and 2B4 (respectively), were lower, which then impaired NK cell-mediated cytotoxic capacity and interferon-γ production. Higher concentrations of transforming growth factor-beta 1 (TGF-β1) were found in sera from persistently infected HBV patients. TGF-β1 down-regulated the expression of NKG2D and 2B4 on NK cells in our in vitro study, leading to an impairment of their effector functions. Anti-TGF-β1 antibodies could restore the expression of NKG2D and 2B4 on NK cells in vitro. Furthermore, TGF-β1 induced cell-cycle arrest in NK cells by up-regulating the expression of p15 and p21 in NK cells from immunotolerant (IT) patients. We conclude that TGF-β1 may reduce the expression of NKG2D/DAP10 and 2B4/SAP, and those IT patients who are deficient in these double-activating signals have impaired NK cell function, which is correlated with persistent HBV infection.

NK cells have been viewed as the most important effectors of the initial antiviral innate immune response. Their activation depends on the integration of signals from “co-activation” receptors, and the cytotoxic effects of NK cells on target cells are tempered by a need for combined signals from multiple activating receptors, such as NKG2D and 2B4. In this study, we showed that NKG2D and 2B4 expression levels were decreased on NK cells from patients in the IT phase of HBV infection. We further demonstrated that lower levels of intracellular adaptor proteins (DAP10 and SAP) were associated with lower surface expression of NKG2D and 2B4. As a result, the synergistically co-activated signalling pathway initiated by NKG2D and 2B4 did not operate properly in IT-phase patients. We demonstrated that high levels of soluble TGF-β1 were associated with the reduction of NKG2D and 2B4 in patients. In addition, we showed that TGF-β1 causes the cell-cycle arrest of NK cells by up-regulating the levels of p15 and p21 in NK cells from IT patients. Collectively, these findings may contribute to our understanding of the immune tolerance mechanism and aid in the development of novel therapeutic methods to clear HBV infection during the initial phase.

Epigenetic repression of E-cadherin expression by hepatitis B virus x antigen in liver cancer

Loss of E-cadherin is associated with acquisition of metastatic capacity. Numerous studies suggest histone deacetylation and/or hypermethylation of CpG islands in E-cadherin gene (CDH1) are major mechanisms responsible for E-cadherin silencing in different tumors and cancer cell lines. The Hepatitis B virus (HBV) encoded X antigen, HBx, contributes importantly to the development of hepatocellular carcinoma (HCC) using multiple mechanisms. Experiments were designed to test if in addition to CDH1 hypermethylation HBx promotes epigenetic modulation of E-cadherin transcriptional activity through histone deacetylation and miR-373. The relationships between HBx, E-cadherin, mSin3A, Snail-1 and miR-373 were evaluated in HBx expressing (HepG2X) and control (HepG2CAT) cells by western blotting, immunoprecipitation, chromatin immunoprecipitation as well as by immunohistochemical staining of liver and tumor tissue sections from HBV infected patients. In HepG2X cells, decreased levels of E-cadherin and elevated levels of mSin3A and Snail-1 were detected. Reciprocal immunoprecipitation with anti-HBx and anti-mSin3A demonstrated mutual binding. Further, HBx-mSin3A co-localization was detected by immunofluorescent staining. HBx down-regulated E-cadherin expression by the recruitment of the mSin3A/HDAC complex to the Snail-binding sites in human CDH1. Histone deacetylation inhibition by Trichostatin A treatment restored E-cadherin expression. Mir-373, a positive regulator of E-cadherin expression, was down-regulated by HBx in HepG2X cells and tissue sections from HBV infected patients. Thus, histone deacetylation of CDH1 and down-regulation of miR-373, together with the previously demonstrated hyper-methylation of CDH1 by HBx, may be important for the understanding of HBV-related carcinogenesis.

Sustained low hepatitis B viral load predicts good outcome after curative resection in patients with hepatocellular carcinoma

BACKGROUND AND AIM

Little is known about the role of hepatitis B virus (HBV) factors in the long-term prognosis of hepatocellular carcinoma (HCC) after resection. The objective of the present study was to identify the changing patterns of HBV levels and its effect on outcome after resection.

METHODS

This study recruited 188 patients with HBV-related HCC who underwent curative resection. Among the 188 patients, 115 were alive without recurrence at 12 months, and had serial measurements of viral levels.

RESULTS

The mean age was 53 years and the mean follow-up period was 48.5 months. With multivariate analysis, tumor size > 5 cm (P = 0.047), Child-Pugh class B (P = 0.017), vascular invasion (P = 0.028), and HBV DNA > 10(4) copies/mL at the time of resection (P = 0.003) were independently predictive of HCC recurrence for the entire population. For the 115 patients with serial measurements of viral levels, tumor size > 5 cm, HBV DNA > 10(4) copies/mL at resection, and the absence of sustained HBV DNA level < 10(4) copies/mL, the presence of cirrhosis, and elevated aminotransferase levels (> 40 IU/L) were marginally or significantly associated with HCC recurrence and overall survival. However, on multivariate analysis, sustained HBV DNA level < 10(4) copies/mL was the only factor for both low recurrence (P = 0.002; odds ratio [OR] 3.13; 95% confidence interval [CI] 1.55-6.35) and longer survival (P = 0.002; OR 3.76; 95% CI 1.61-8.78).

CONCLUSIONS

A high HBV replication state is among the most important predictors of adverse outcome after resection of HBV-related HCC. The sustained suppression of HBV below 10(4) copies/mL is a strong protective factor for long-term recurrence-free and overall survival.

High hepatitis B viral load predicts recurrence of small hepatocellular carcinoma after curative resection

A retrospective cohort study was conducted to identify risk factors for recurrence of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after curative resection. A total of 317 patients who had received curative resection of pathologically proven small HCC (< or = 3 cm in diameter) were analyzed to ascertain the factors affecting recurrence. The median follow-up period was 33.7 months. Cumulative recurrence rates at 1, 3, and 5 years after resection were 23.5%, 49.5%, and 65.5%, respectively. Male sex, alpha-fetoprotein (AFP) > or = 400 ng/mL, HBV DNA level > or = 4 log(10) copies/mL, prolonged prothrombin time, tumor size > or = 2 cm, microvascular invasion, absence of capsular formation, moderate/poor tumor differentiation, and absence of postoperative interferon-alpha (IFN-alpha) treatment were associated with increased cumulative risk of HCC recurrence. By multivariate analysis, HBV DNA level > or = 4 log(10) copies/mL (P < 0.001, hazard ratio (HR) 2.110), AFP > or = 400 ng/mL (P = 0.011, HR 1.574), microvascular invasion (P < 0.001, HR 1.767), and postoperative IFN-alpha treatment (P = 0.022, HR 0.562) remained to be independently associated with HCC recurrence. Those contributing to late recurrence (>2 years) were older age and HBV DNA level > or = 4 log(10) copies/mL. Patients with persistent HBV DNA level > or = 4 log(10) copies/mL at resection and follow-up had the highest recurrence risk (P < 0.001, HR 4.129). HBV DNA level > or = 4 log(10) copies/mL at the time of resection was the most important risk factor for recurrence. Postoperative IFN-alpha treatment significantly decreased the recurrence risk after resection.

The influence of hepatitis B DNA level and antiviral therapy on recurrence after initial curative treatment in patients with hepatocellular carcinoma

BACKGROUND

Prediction and prevention of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) recurrence is an important clinical issue. We investigated whether HBV DNA level and antiviral therapy are associated with HCC recurrence.

METHODS

This retrospective study involved 103 patients who underwent hepatic resection or radiofrequency ablation for initial HCC. Patients were divided into four groups. Thirty had high serum HBV DNA levels (>4 log(10) copies/mL) and had not received antiviral therapy (high virus group; HVG). Thirty-four had low HBV DNA levels (< or =4 log(10) copies/mL) and had not received antiviral therapy (low virus group; LVG). Twenty received antiviral therapy after HCC developed (therapeutic group A, TG-A). Nineteen received antiviral therapy before HCC developed (therapeutic group B, TG-B).

RESULTS

Cumulative HCC recurrence rates at 3 years in the HVG, LVG, TG-B, and TG-A were 71.1%, 42.2%, 42.3%, and 52.0%, respectively. Recurrence rates differed significantly between the HVG and LVG (P = 0.016) and between the HVG and TG-B (P = 0.008). Recurrence rate in the TG-A was marginally lower than in the HVG (P = 0.10). On multivariate analysis, high serum hepatitis B virus DNA levels (hazard ratio: HR 2.67; 95% CI 1.31-5.47; P = 0.007) and absence of antiviral therapy (HR 2.57; 95% CI 1.34-4.94; P = 0.005) were independent risk factors for hepatocellular carcinoma recurrence.

CONCLUSION

HBV DNA level and antiviral therapy are associated with HCC recurrence. For patients with high HBV DNA levels, antiviral therapy before the development of HCC is important for prevention of recurrence.

Putative roles of hepatitis B x antigen in the pathogenesis of chronic liver disease

Under most circumstances, hepatitis B virus (HBV) is noncytopathic. However, hepatocellular regeneration that accompanies each bout of hepatitis appears to be associated with increased integration of HBV DNA fragments expressing the virus encoded hepatitis B x antigen (HBxAg). Intrahepatic HBxAg staining correlates with the intensity and progression of chronic liver disease (CLD), and additional work has shown that HBxAg blocks immune mediated killing by Fas and by tumor necrosis factor alpha (TNFalpha). This is not only associated with the blockage of caspase activities by HBxAg, but also by the constitutive stimulation of hepatoprotective pathways, such as nuclear factor kappa B (NF-kappaB), phosphoinositol 3-kinase (PI3K), and beta-catenin (beta-catenin). HBxAg also appears to promote fibrogenesis, by stimulating the production of fibronectin. HBxAg also stimulates the production and activity of transforming growth factor beta1 (TGFbeta1) by several mechanisms, thereby promoting the profibrogenic and tumorigenic properties of this important cytokine. In addition, HBxAg appears to remodel the extracellular matrix (ECM) by altering the expression of several matrix metalloproteinases (MMPs), which may promote tumor metastasis. Hence, HBxAg appears to promote chronic infection by preventing immune mediated apoptosis of infected hepatocytes, by promoting the establishment and persistence of fibrosis and cirrhosis preceding the development of HCC, and by promoting the remodeling of EMC during tumor progression.

HBV X protein: elucidating a role in oncogenesis

Chronic HBV infection is associated with the development of hepatocellular carcinoma (HCC). HBV contributes to tumorigenesis by encoding hepatitis B x antigen (HBxAg), which is a trans-regulatory protein that appears to contribute to HCC by altering patterns of host gene expression. In this review, recent data is presented that outlines some of the putative mechanisms whereby HBxAg contributes to HCC. With the development of animal models of HBxAg-mediated HCC, the relevance and temporal order of putative steps in this process can now be dissected to elucidate what is rate limiting and when. This will have a profound impact on the design of novel and specific therapeutics for HCC.

Recurrence of hepatitis B-related hepatocellular carcinoma is associated with high viral load at the time of resection

BACKGROUND/AIMS

To identify the risk factors for recurrence of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) after resection.

METHODS

Seventy-two patients who underwent liver resection for HBV-related HCC were recruited. Demographic, biochemical, tumor, and viral factors at the time of resection were evaluated by univariate and multivariate analyses to identify risk factors associated with recurrence after resection.

RESULTS

The median follow-up period was 18.9 months and the median age was 53 yr, with male-to-female ratio of 59:13. Age >60 yr, tumor size >5 cm, poorly differentiated tumor, lymphovascular permeation, the presence of microsatellite lesions, alpha-fetoprotein (AFP) level >1,000 ng/mL and HBV viral load >2,000 IU/mL (4 log(10) copies/mL) at the time of tumor resection, HBV genotype C, core promoter mutations, and patients with no antiviral treatment after tumor resection were associated with increased cumulative risk of HCC recurrence. By multivariate analysis, HBV viral load >2,000 IU/mL (4 log(10) copies/mL) (P= 0.001, odds ratio [OR] 22.3), AFP >1,000 ng/mL (P= 0.02, OR 7.4), tumor size >5 cm (P= 0.02, OR 5.1), and age >60 yr (P= 0.01, OR 4) at the time of tumor resection remained to be the independent risk factors.

CONCLUSIONS

Viral load of >2,000 IU/mL (4 log(10) copies/mL) is the most important correctable risk factor for HCC recurrence after resection. Whether antiviral therapy in these patients can decrease tumor recurrence requires further investigations.

Whole genome expression profiling of hepatitis B virus-transfected cell line reveals the potential targets of anti-HBV drugs

Hepatitis B virus (HBV) infection is a major health concern world wide, and few effective treatments have been developed. It has recently been reported that inhibiting host-cell proteins can prevent viral infection. The human genome may contain more genes required for HBV infection and replication than the viral genome. A systematic approach to find these potential antiviral targets is by host gene expression analysis using DNA microarrays. The aim of this study was to identify and validate novel cellular anti-HBV targets. The Human Whole Genome Bioarray was used to analyze differentially expressed genes in HepG2.2.15 cells and HepG2 cells. Altered gene expression in HepG2.2.15 cells was studied following treatment with the anti-HBV drug, lamivudine. Genes that were differentially expressed during HBV infection and reversed with anti-HBV drugs were validated by semiquantitative reverse transcription-PCR. Bioinformatics analysis revealed ABHD2, EREG, ACVR2B, CDC34, KHDRBS3 and RORA as potential cellular anti-HBV targets. Antisense oligodeoxynucleotides were used to test the antiviral activity of these potential targets. Results strongly suggested that inhibition of ABHD2 or EREG significantly blocked HBV propagation in HepG2.2.15 cells. This study demonstrates that ABHD2 and EREG are essential for HBV propagation and provides strong evidence that these proteins could be used as potential targets for anti-HBV drugs.

Plasma transforming growth factor β1, metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 in acute viral hepatitis type B

AIM

Antiproliferative, pro-apoptotic and immunosuppressive activity effects suggest crucial role of transforming growth factor (TGF)-beta1, metalloproteinase (MMP)-1 and its tissue inhibitor (TIMP)-1 in the pathogenesis of acute liver injury that in some patients precede development of chronic liver diseases and fibrogenesis. The aim of this study was to evaluate effect of acute HBV infection on plasma TGF-beta1, MMP-1 and TIMP-1 levels.

METHODS

TGF-beta1, MMP-1 and TIMP-1 plasma concentrations were measured with an enzyme immunoassay in 39 patients with acute viral hepatitis type B. Baseline measurement was performed within the first week of jaundice and then weekly up to the fourth week of the disease. Results were compared to baseline and normal values and to liver function tests.

RESULTS

Plasma concentrations of TGF-beta1, TIMP-1 and MMP-1 were significantly elevated in the first week of acute viral B hepatitis in comparison to normal. Analysis of individual values demonstrated significant positive correlation between plasma concentrations of TGF-beta1 and TIMP-1. There was no correlation between MMP-1 and TGF-beta1 or TIMP-1. Significant correlation was demonstrated between both TGF-beta1 and ALT or AST as well as between TIMP-1 and ALT, AST or bilirubin. Elevated baseline levels of both TGF-beta1 and TIMP-1 decreased gradually in consecutive weeks of the disease. TGF-beta1 but not TIMP-1 plasma concentrations were significantly lower in 3rd and 4th week than baseline values. MMP-1 concentration remained on baseline level in the 2nd week of the disease. However in the 3rd week its values increased suddenly but the significant difference in comparison to baseline was observed only in 4th week.

CONCLUSIONS

These results indicate important role of TGF-beta1, TIMP-1 and MMP-1 in acute viral hepatitis, that seems to be connected first of all with hepatocytes damage. Their role in extracellular matrix metabolism during acute liver injury needs further evaluation.

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