Overexpression of HBxAg in hepatocellular carcinoma and its relationship with Fas/FasL system

HBV and HIV/HBV Infected Patients Have Distinct Immune Exhaustion and Apoptotic Serum Biomarker Profiles

Background:

Hepatitis B virus (HBV) infection is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma worldwide. Due to their shared routes of transmission, approximately 10% of HIV-infected patients worldwide are chronically coinfected with HBV. Additionally, liver disease has become a major cause of morbidity and mortality in HBV/HIV coinfected patients due to prolonged survival with the success of antiretroviral therapy. The relationship between immune exhaustion markers (PD-1/PD-L1) and apoptotic markers such as Fas/FasL, TGFβ1, TNF-α, and Th1/Th2 cytokines are not clearly delineated in HBV/HIV coinfection.

Methods:

Levels of soluble Fas/FasL, TGFβ1, TNF-α, and sPD-1/sPD-L1 as well as Th1 and Th2 cytokines were evaluated in the sera of HBV-monoinfected (n = 30) and HBV/HIV-coinfected (n = 15) patients and compared to levels in healthy controls (n = 20).

Results:

HBV-monoinfected patients had significantly lower levels of the anti-inflammatory cytokine IL-4 (P < 0.05) and higher levels of apoptotic markers sFas, sFasL, and TGFβ-1 (P < 0.001) compared to healthy controls. Coinfection with HIV was associated with higher levels of sFas, TNF-α, and sPD-L1 (P < 0.005), and higher levels of the pro-inflammatory cytokines IL-6, IL-8, and IL-12p70 (P < 0.05) compared to healthy controls. Patients with HBV infection had a unique biomarker clustering profile comprised of IFN-γ, IL12p70, IL-10, IL-6, and TNF-α that was distinct from the profile of the healthy controls, and the unique HIV/HBV profile comprised GM-CSF, IL-4, IL-2, IFN-γ, IL12p70, IL-7, IL-10, and IL-1β. In HBV monoinfection a significant correlation between sFasL and PD1(r = 0.46, P = < 0.05) and between sFas and PDL1 (r = 0.48, P = <0.01) was observed.

Conclusion:

HBV-infected and HBV/HIV-coinfected patients have unique apoptosis and inflammatory biomarker profiles that distinguish them from each other and healthy controls. The utilization of those unique biomarker profiles for monitoring disease progression or identifying individuals who may benefit from novel immunotherapies such as anti-PD-L1 or anti-PD-1 checkpoint inhibitors appears promising and warrants further investigation.

Evaluation of alternative serum biomarkers to monitor the progression of chronic HBV and HCV infection

Chronic hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are among the most serious health conditions affecting about 600 million people worldwide leading to a number of severe liver diseases. Due to the lack of warning signs or mild symptoms during the early stage of the infection, a molecular signature associated with disease progression would be useful. Based on our recent paper where candidate biomarkers were determined through topological and modularity analysis of protein interaction networks (PINs), this study was focused on the evaluation of MIF, TNFRSF1A, FAS and TMSB4X as diagnostic biomarkers in chronic HBV and HCV infections. The aim was to establish a molecular profile, by combining those markers, that would discriminate the different stages during the progression of chronic hepatitis. One hundred and fifteen patients infected with HBV or HCV categorized into three groups: non-cirrhotic, cirrhotic and with HCC, and 20 healthy subjects were enrolled in this study. Serum levels of the aforementioned factors were measured by ELISA. TNFRSF1A serum levels appeared statistically significantly increased in all patient groups compared to control group with a p-value of <0.05. Furthermore, the combination of TNFRSF1A and TMSB4X serum levels successfully classified 63, 47% of patients indicating an association with HBV and HCV infections. Thus, variations of serum levels of TNFRSF1A and TMSB4X could be associated with the different stages of the disease and may be utilized for further research. On the other hand, we found no contribution of MIF and FAS serum levels for successful classification of patients.

Genetic Polymorphisms of Fas/FasL Promoter Associated with Hepatitis C cirrhosis and HCC

Aim:

The present study was performed to determine any associations of genetic polymorphisms of Fas/FasL promoter regions, at Fas670 and Fas1377 and FasL844, with hepatitis C cirrhosis and HCC, with a focus on severity of disease.

Methods:

Totals of 120 patients with cirrhosis and 101 with hepatocellular carcinoma (HCC) were enrolled. All had chronic HCV infection as indicated by positive anti-HCV antibodies and positive HCV RNA on real time PCR. One hundred healthy control subjects were also included in the study. Patients were subjected to full clinical, radiological and histopathological examinations. In addition to routine laboratory tests for liver function tests, Fas670 and Fas1377 and FasL844 genetic polymorphisms of Fas/FasL promoter regions were assessed by RFLP-PCR (restriction fragment length polymorphism with polymerase chain reaction).

Results:

Significant higher levels of the AG genotype in Fas670 and Fas1773 were observed in patients with cirrhosis and HCC (P=0.0001) as compared to control subjects. In addition, the CC genotype in FASL844 was also more common in patients (P=0.01). Furtehrmore, there was a significant association of substitution of A by G alleles in Fas670 and Fas1773 with advanced BCA staging (P=0.02, P=0.0001 respectively) and larger tumor size >5cm (P=0.01, P=0.0001 respectively) and in Fas670 with advanced pathological grading (P=0.0001). Moreover the CC genotype of FASL844 was significantly linked with advanced BCA, large tumor size >5cm and advanced pathological grading (P=0.0001).

Conclusion:

The findings of the present study highlight associations of genetic polymorphisms of promoter regions in Fas and Fas L with cirrhosis and HCC associated with chronic HCV. Support was also obtained for the conclusion that single nucleotide polymorphisms of the Fas/ FasL system impact on clinical and histopathological grading of HCCs. Further large scale studies are recommended for confirmation.

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.

Immunopathology on hepatocyte expression of HBV surface, core, and x antigens in chronic hepatitis B: clinical and virological correlation

PURPOSE

Hepatocyte expression of HBV surface, core, and x antigens (HBsAg, HBcAg and HBxAg), semi-quantitated by immunopathology, were correlated with clinical and virological data in 80 patients with chronic hepatitis B.

RESULTS

Seventy patients were HBsAg positive in cytoplasm, 61 were HBcAg positive, including 45 in both nucleus and cytoplasm and 16 in cytoplasm only, and 47 were HBxAg positive in cytoplasm. The detection rates for HBcAg increased while those for HBsAg and HBxAg decreased with HBV DNA levels. Positive HBcAg staining usually suggested the presence of HBV DNA levels >10(6) copies/ml. HBcAg, HBsAg, and HBxAg expressions showed no significant differences between patients with genotype B and C. Serum HBeAg and HBV DNA levels correlated positively with nuclear or cytoplasmic HBcAg expression but inversely with HBsAg expression. By multiple regression analysis, HBV DNA levels correlated significantly only with nuclear HBcAg expression. ALT levels and inflammatory grades correlated with cytoplasmic HBcAg expression. There was an inverse quantitative relationship between HBcAg and HBsAg expression. Furthermore, HBxAg expression correlated significantly with HBsAg expression as well as male gender.

CONCLUSIONS

With diminishing HBV DNA levels following HBeAg seroconversion, HBcAg expression decreased but HBsAg expression increased with a concomitant increase in HBxAg expression. Whether the finding that a significantly higher expression of HBxAg observed in males than females may account for the gender difference in long-term sequelae of chronic HBV infection needs further investigation.

Separate origins of hepatitis B virus surface antigen-negative foci and hepatocellular carcinomas in transgenic HBsAg (alb/psx) mice

We have examined the development and transgene expression in liver lesions of transgenic mice bearing the hepatitis B surface antigen (HBsAg) gene of hepatitis B virus under the control of the albumin promoter (alb/psx) to study liver regeneration and hepatocellular carcinoma (HCC) associated with hepatitis B virus infection. Storage of the HBsAg in the endoplasmic reticulum precedes loss of liver cells and regenerative hyperplastic nodules that do not express HBsAg. Histological analysis indicated that HBsAg-negative foci and nodules arose from liver progenitor cells in the portal zone and lacked mRNA expression. Genomic DNA from eight of nine HBsAg-negative laser capture-excised liver foci showed loss of part of the alb/psx gene, whereas no loss of the actin gene was observed. The alb/psx DNA was intact in adjacent HBsAg-positive tissue. Sequencing of polymerase chain reaction products suggested that alterations in the HBsAg transgene in HBsAg-negative foci occurred via large-scale deletions as opposed to single-site mutations. Southern blot analysis of HCC from 2-year-old transgenic HBsAg mice, however, revealed an intact alb/psx gene. Thus, HBsAg-negative progenitor cells with deletions in the transgene appear to be responsible for compensatory regeneration of the liver, whereas HCCs arise from clonal expansion of hepatocytes with intact alb/psx transgenes.

Targeting Drugs to Combinations of Receptors: A Modeling Analysis of Potential Specificity

Targeting drugs to specific cells by conjugating the drug to an antibody or ligand for a cell surface receptor currently requires that the receptor be uniquely over-expressed by the target cell (the target cell over-expresses a particular receptor in comparison with untargeted cells, which do display this receptor type but a lesser number of them). Here we develop a mathematical model to predict the behavior of multivalent ligand-drug constructs containing two different ligands for two different receptors, which would allow targeting cells that do not uniquely over-express any receptor. In this model, target cells express both receptors at a high level; whereas, untargeted cells express one receptor type at the high level but the other at a lower level. The model predicts that these heterovalent conjugates (containing two different types of ligands) can achieve specificity even when the target cell does not uniquely over-express any one receptor type. Using the current approach, constructs in which only one ligand type is used will bind as much to untargeted cells as to the target cells. Therefore, this combination strategy can enormously expand the number of applications for which cell surface receptor targeting of drugs is an appropriate option.

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Construction of hepatitis B virus X gene expression vector in eucaryotic cells and its transfection in HL-7702 cells

AIM: To establish a human hepatocyte cell line which can express hepatitis B virus (HBV) X gene.

METHODS: HBV X gene was obtained through PCR techn-ology. After A-tailing added, X gene was connected into vector PUCmT. Vector PUCmT-X and PcDNA3 were digested with EcoRI and HindIII. The fragments of X and PcDNA3 were connected to establish reconstituted plasmid PcDNA3-X. Then PcDNA3-X and PcDNA3 were transfected into HL-7702 cells by lipid-mediated transfection. After selected with G418, HL-7702/HBx cells were analysed by the reverse transcription-PCR to confirm the steady expression of X gene in HL-7702.

RESULTS: Reconstituted plasmid PcDNA3-X included the anticipated fragment of HBV X gene was proved by auto-sequencing assay. RT-PCR analysis showed that reconstituted plasmid PcDNA3-X could express the X protein efficiently in HL-7702 cells.

CONCLUSION: Hepatocyte can express HBV X gene, which is an ideal model to study the effect of HBV X gene on the development of hepatitis and hepatocelular carcinoma.