Hepatitis B surface antigen-negative but hepatitis B envelope antigen-positive false occult hepatitis B virus infection:A case report

BACKGROUND Occult hepatitis B infection(OBI)is characterized by the detection of hepatitis B virus(HBV)DNA in serum(usually HBV DNA<200 IU/mL)or the liver but negativity for hepatitis B surface antigen(HBsAg).The diagnosis of OBI relies on the sensitivity of assays used in the detection of HBV DNA and HBsAg.HBsAg assays with inadequate sensitivity or inability to detect HBV S variants may lead to misdiagnosis of OBI in people with overt HBV infection.CASE SUMMARY We report a HBsAg-negative but hepatitis B envelope antigen-positive patient who had a significant HBV DNA level.The patient was initially diagnosed as having OBI.However,sequence analysis revealed a unique insertion of amino acid residues at positions 120-124 in the S protein,which affects the formation of a disulfide bond that is associated with the formation of a loop.It is well known that there is an overlap between the S protein and Pol protein.We found that this new insertion site occurred in polymerase/reverse transcriptase domain,indi-cating that this insertion might be involved in HBV pathogenicity.The patient was finally diagnosed with a false OBI.CONCLUSION An insertion of amino acid residues at positions 120-124 of the S protein affects the formation of immunodominant epitopes and results in negative HBsAg levels.

Hepatitis B virus X protein-mediated upregulation of miR-221 activates the CXCL12-CXCR4 axis to promote NKT cells in HBVrelated hepatocellular carcinoma

Both hepatitis B virus X protein(HBx)and microRNA-221(miR-221)have been implicated in the development of hepatitis B virus(HBV)-related hepatocellular carcinoma(HCC).The present study demonstrates that HBx promotes HCC cell proliferation via the C-X-C motif chemokine ligand 12-C-X-C chemokine receptor type 4(CXCL12-CXCR4)axis.We predict that HBx/miR-221-mediated CXCL12/CXCR4 signaling induces NKT cells to promote HBV-related HCC.Methods:After miR-221 mimic,miR-221 mimic negative control,miR-221 inhibitor,miR-221 inhibitor negative control were transfected into cells,the expression of CXCL12 and miR-221 was detected by qPCR and western blot.Then we constructed a stable HBV-HCC cell line.HBV-HCC cells were injected into the nude mice,thus a HBV-HCC mouse model was constructed.Q-PCR and western blot were used to detect the expression of HBx,miR-221,CXCL12 and CXCR4 in tumor tissues.The expression of CXCL12 was detected by immunohistochemistry,and the expression of CXCR4,CD3 and CD56 was detected by immunofluorescence.The levels of CXCL12,IL-2 and TNF-αin serum of mice were detected by ELISA.Sixty-one patients with HBV-related HCC,61 patients with HBV-related cirrhosis,61 patients with chronic hepatitis B(CHB)and 30 healthy people were enrolled.CXCL12,cytokine levels,and clinicopathological parameters were tested.Results:Hepatitis B virus X protein upregulates the expression of miR-221 and CXCL12 in lentivirus(LV5)-HBx-transfected HepG2 cells.HBx protein promotes HepG2 cell proliferation in vitro.HBx protein promoted tumor growth via the miR-221/CXCL12/CXCR4 pathway in a mouse tumor model.HBx protein upregulated natural killer T cell expression via the CXCR4/CXCL12 pathway to promote tumor growth.The data demonstrated a positive correlation between CXCL12 concentration with Cre levels and Child-Pugh scores.CXCL12 had an inferior diagnostic efficiency compared to IL-2 and IL-6 for HBV-related HCC.Conclusions:We present evidence that HBx/miR-221-mediated CXCL12/CXCR4 signaling induces NKT cells to promote HBV-related HCC.

The Expression of Sperm Membrane Peptide-Hepatitis B SurfaceAntigen Fusion Protein with Recombinant Vaccinia Virus

A synthetic oligonucleotide, HSD-2a, encoding a peptide segment of the extracel-lular domain of a human sperm membrane protein, YWK-II, was fused with hepatitisB surface antigen gene (HBs gene ). The fused gene was then cloned to pUC18plasmid. The fused gene was prepared from the recombinant pUC18 plasmid byBamH I and Eco R I digestion, and then cloned into the transfer vector pGJP- 5 underthe control of P;., promoter, designated as pGJP-HSD/HBs. CV-1 cells were co-transfected with vaccinia virus (Tian Tan strain) and pGJP-HSD/IIBs and homolo-gous re combination occurred between the vaccinia virus TK gene of the plasmid flank-ing the foreign gene and the same sequences within the virus genome. TK phen0tyPerecombinant virus, vv-HSD/HBs, were selected from trandected HuTK' cells byplaque purthcation technique. The eopressi0n of HSD-b in spent medium and cellu-lar protein of HuTK cells infected with vv-HSD/HBs was determined by ELISAand Western-blot analysis using anti-rwK-II antiserum. The present study indicatesthat the vv-HSD/HBs seems promising as an antdertility vaccine.

Inhibition of apoptosis by oncogenic hepatitis B virus X protein: Implications for the treatment of hepatocellular carcinoma

Hepatitis B virus X protein(HBx) plays an important role in the development of hepatocellular carcinoma(HCC). In addition, hepatoma upregulated protein(HURP) is a cellular oncogene that is upregulated in a majority of HCC cases. We highlight here recent findings demonstrating a link between HBx, HURP and anti-apoptosis effects observed in cisplatin-treated HCC cells. We observed that Hep3B cells overexpressing HBx display increased HURP mRNA and protein levels, and show resistance to cisplatin-induced apoptosis. Knockdown of HURP in HBx-expressing cells reverses this effect, and sensitizes cells to cisplatin. The anti-apoptotic effect of HBx requires activation of the p38/MAPK pathway as well as expression of SATB1, survivin and HURP. Furthermore, silencing of HURP using short-hairpin RNA promotes accumulation of p53 and reduces cell proliferation in SK-Hep-1 cells(p53^(+/–)), whereas these effects are not observed in p53-mutant Mahlavu cells. Similarly, HURP silencing does not affect the proliferation of H1299 lung carcinoma cells or Hep3 B HCC cells which lack p53. Silencing of HURP sensitizes SK-Hep-1 cells to cisplatin. While HURP overexpression promotes p53 ubiquitination and degradation by the proteasome, HURP silencing reverses these effects. Inoculation of SK-Hep-1 cancer cells in which HURP has been silenced produces smaller tumors than control in nude mice. Besides, gankyrin, a positive regulator of the E3 ubiquitin ligase MDM2, is upregulated following HURP expression, and silencing of gankyrin reduces HURP-mediated downregulation of p53. In addition, we observed a positive correlation between HURP and gankyrin protein levels in HCC patients(r^2 = 0.778; n = 9). These findings suggest a role for the viral protein HBx and the host protein HURP in preventing p53-mediated apoptosis during cancer progression and establishment of chemoresistance.

Hepatitis B virus reactivation and hepatitis in diffuse large B-cell lymphoma patients with resolved hepatitis B receiving rituximab-containing chemotherapy:risk factors and survival

Introduction:Hepatitis B virus(HBV) reactivation has been reported in B-cell lymphoma patients with resolved hepatitis B(hepatitis B surface antigen[HBsAg]-negative and hepatitis B core antibody[HBcAb]-positive).This study aimed to assess HBV reaaivation and hepatitis occurrence in diffuse large B-cell lymphoma(DLBCL) patients with resolved hepatitis B receiving rituximab-containing chemotherapy compared with HBsAg-negative/HBcAb-negative patients to identify risk factors for HBV reaaivation and hepatitis occurrence and to analyze whether HBV reaaivation and hepatitis affect the survival of DLBCL patients with resolved hepatitis B.Methods:We reviewed the clinical data of 278 patients with DLBCL treated with rituximab-containing therapy between January 2004 and May 2008 at Sun Yat-sen University Cancer Center,China.Prediaive faaors for HBV reaaivation,hepatitis development,and survival were examined by univariate analysis using the chi-square or Fisher's exact test and by multivariate analysis using the Cox regression model.Results:Among the 278 patients,165 were HBsAg-negative.Among these 165 patients,6(10.9%) of 55 HBcAb-positive(resolved HBV infeaion) patients experienced HBV reactivation compared with none(0%) of 110 HBcAb-negative patients(P=0.001).Patients with resolved hepatitis B had a higher hepatitis occurrence rate than HBsAg-negative/HBcAb-negative patients(21.8%vs.8.2%,P = 0.013).HBcAb positivity and elevated baseline alanine aminotransferase(ALT) levels were independent risk factors for hepatitis.Among the 55 patients with resolved hepatitis B,patients with elevated baseline serum ALT or aspartate aminotransferase(AST) levels were more likely to develop hepatitis than those with normal serum ALT or AST levels(P = 0.037,P = 0.005,respeaively).An elevated baseline AST level was an independent risk factor for hepatitis in these patients.Six patients with HBV reactivation recovered after immediate antiviral therapy,and chemotherapy was continued.HBcAb positivity,HBV reactivation,or hepatitis did not negatively affect the survival of DLBCL patients.Conclusions:DLBCL patients with resolved hepatitis B may have a higher risk of developing HBV reaaivation and hepatitis than HBsAg-negative/HBcAb-negative patients.Close monitoring and prompt antiviral therapy are required in these patients.

Novel Evidence Suggests Hepatitis B Virus Surface Proteins Participate in Regulation of HBV Genome Replication

Naturally occurring mutations in surface proteins of Hepatitis B virus(HBV) usually result in altered hepatitis B surface antigen(HBsAg) secretion efficiency.In the present study,we reported two conserved residues,M75 and M103 with respect to HBsAg,mutations of which not only attenuated HBsAg secretion(M75 only),but also suppressed HBV genome replication without compromising the overlapping p-gene product.We also found M75 and M103 can initiate truncated surface protein(TSPs) synthesis upon over-expression of full-length surface proteins,which may possibly contribute to HBV genome replication.However,attempts to rescue replicationdefective HBV mutant by co-expression of TSPs initiated from M75 or M103 were unsuccessful,which indicated surface proteins rather than the putative TSPs were involved in regulation of HBV genome replication.

The influence of hepatitis B virus X protein on the clock genes in liver cells and its significance

Objective： The aim of this study was to investigate the influence of hepatitis B virus X protein （HBx） on the clock genes in LO2 cells and its significance. Methods： A cell line LO2-HBx, Stably transfected with HBx gene, was established. The levels of mRNA and protein expression of CLOCK and BMAL1 were detected by real-time PCR and western blot. Resuits： The expression of CLOCK mRNA and protein were increased in cell line LO2-HBx （P 〈 0.05）, while the expression of BMAL1 mRNA and protein were decreased in cell line LO2-HBx （P 〈 0.05）. Conclusion： The expressions of core clock gene CLOCK and BMAL1 have been changed by HBx, which breaks down the previous circadian rhythm of liver cells. This maybe one of the reasons leads to the formation of liver cancer.

Hepatitis B virus X protein accelerates the development of hepatoma

The chronic infection of hepatitis B virus(HBV) is closely related to the occurrence and development of hepatocellular carcinoma(HCC). Accumulated evidence has shown that HBV X protein(HBx protein) is a multifunctional regulator with a crucial role in hepatocarcinogenesis. However, information on the mechanism by which HBV induces HCC is lacking. This review focuses on the pathological functions of HBx in HBV-induced hepatocarcinogenesis. As a transactivator, HBx can modulate nuclear factor kappa-light-chain-enhancer of activated B cells(NF-κB) and transcription factor AP-2. Moreover, HBx can affect regulatory non-coding RNAs(ncRNAs) including microRNAs and long ncRNAs(lncRNAs), such as miRNA-205 and highly upregulated in liver cancer(HULC), respectively. HBx is also involved in epigenetic modification, including methylation and acetylation. HBx interacts with various signal-transduction pathways, such as protein kinase B/Akt, Wnt/β-catenin, signal transducer and activator of transcription, and NF-κB pathways. Moreover, HBx affects cellular fate by shifting the balance toward cell survival. HBx may lead to the loss of apoptotic functions or directly contributes to oncogenesis by achieving transforming functions, which induce hepatocarcinogenesis. Additionally, HBx can modulate apoptosis and immune response by direct or indirect interaction with host factors. We conclude that HBx hastens the development of hepatoma.

Hepatitis B virus X protein regulates the mEZH2 promoter via the E2F1-binding site in AML12 cells

Histone lysine methyltransferase EZH2 has been reported to be frequently overexpressed in hepatocellular carcinoma(HCC) tissues and associated with hepatocarcinogenesis.However,the exact mechanism of EZH2 up-regulation in HCC has not been determined.In this study,we used murine hepatocyte AML12 cells to investigate the role of hepatitis B virus X protein(HBx) in regulating the expression of mEZH2.Western blot analysis demonstrated that the expression level of mEZH2 protein in AML12 cells was up-regulated by HBx in a dose-dependent manner.To further investigate the mechanism of mEZH2 overexpression,the 2500 bp regulatory sequence upstream from the first exon of the mEZH2 gene was amplified from AML12 genomic DNA and constructed into a luciferase reporter plasmid.The luciferase activity of the mEZH2 promoter significantly increased in AML12 cells co-transfected with HBx plasmid,and deleting the-486/-214 promoter region decreased HBx-induced mEZH2 promoter activation by nearly 50%.The-486/-214 region was then analyzed in the TRANSFAC 6.0 database and a typical E2F1-binding site was found.Mutation of this E2F1-binding site or knockdown of E2F1 expression by RNAi led to a dramatic decrease in HBx-induced activation of the mEZH2 promoter and mEZH2 overexpression in AML12 cells.These results provide evidence that HBx up-regulates mEZH2 expression by transactivating the mEZH2 promoter through E2F1 transcription factor,thereby providing new epigenetic evidence for the carcinogenic effect of HBx.

Screening and cloning for proteins transactivated by the PS1TP5 protein of hepatitis B virus:A suppression subtractive hybridization study

AIM： To clone and identify human genes transactivated by PSITP5 by constructing a cDNA subtractive library with suppression subtractive hybridization （SSH） technique. METHODS： SSH and bioinformatics techniques were used for screening and cloning of the target genes transactivated by PS1TP5 protein. The mRNA was isolated from HepG2 cells transfected with pcDNA3.1（-）- myc-his（A）-PS1TP5 and pcDNA3.1（-）-myc-his（A） empty vector, respectively, and SSH technique was employed to analyze the differentially expressed DNA sequence between the two groups. After digestion with restriction enzyme Rsa Ⅰ, small size cDNAs were obtained. Then tester cDNA was divided into two groups and ligated to the specific adaptor 1 and adaptor 2, respectively. The tester cDNA was hybridized with driver cDNA twice and subjected to nested PCR for two times, and then subcloned into T/A plasmid vectors to set up the subb-active library. Amplification of the library was carried out with E.. coil strain DH5α. The cDNA was sequenced and analyzed in GenBank with Vector NTI 9.1 and NCBI BLAST software after PCR amplification. RESULTS： The subtractive library of genes transactivated by PS1TP5 was constructed successfully. The amplified library contained 90 positive clones. Colony PCR showed that 70 clones contained 200-1000-bp inserts. Sequence analysis was performed in 30 clones randomly, and the full-length sequences were obtained by bioinformatics technique. Altogether 24 coding sequences were obtained, which consisted of 23 known and 1 unknown.One novel gene with unknown functions was found and named as PSITP5TP1 after being electronically spliced, and deposited in GenBank （accession number： DQ487761）. CONCLUSION： PSITP5 is closely correlated with immunoregulation, carbohydrate metabolism, signal transduction, formation mechanism of hepatic fibrosis, and occurrence and development of tumor. Understanding PSlTP5 transactive proteins may help to bring some new clues for further studying the biological functions of pre-S1 protein.

Autophagy related protein 9A increase in hepatitis B virusassociated hepatocellular carcinoma and the role in apoptosis

The majority of hepatocellular carcinoma(HCC)cases are associated with the hepatitis B virus(HBV)infection.Autophagy related protein 9A(ATG9A)is a transmembrane protein required for autophagosome formation.In order to investigate the role of ATG9A in HBV-associated HCC,ATG9A protein expression was determined in tumor liver tissues and compared with adjacent nontumor tissues from HCC patients with or without HBV infection.In HBVassociated HCC tissues,ATG9A protein level was increased in tumor liver tissues,but not in cases of non-HBV HCC.Our findings suggested that ATG9A might be involved in HBV and cancer cell survival.Therefore,we aimed to analyze the function of ATG9A in HBV replication using RNA interference to evaluate the HBV DNA level using real-time PCR.In the present study,there were no significant differences between shATG9A-transfected HepG2.2.15 cells and the mock control.However,we found that silencing ATG9A affected apoptosis in HepG2.2.15 and HepG2 cell lines.Our results indicated that ATG9A might be partly involved in the survival of HCC.Thus,the inhibition of ATG9A together with other targets might be a potential drug target for HCC treatment.

Experimental study about Hepatitis B virus X protein (HBx) promotion on the liver cancer cell line growth as well as its molecular mechanism

Objective:To study the effect of hepatitis B virus X protein (HBx) on the expression of proliferation molecules, invasion molecules and angiogenesis molecules in liver cancer cell lines.Methods: Liver cancer cell lines HepG2 were cultured and divided into HBx group and control group that were transfected with pcDNA3.1-HBx plasmid and blank pcDNA3.1 plasmid respectively. 24 h and 48 h after transfection, the mRNA expression of proliferation molecules Survivin, cyclinD1 and c-myc, invasion molecules CD44v6, MT1-MMP, MMP2 and MMP7 as well as angiogenesis molecules VEGF, Ang-1, Ang-2 and FGF-2 in cells were determined.Results:After 24 h and 48 h of transfection, the Survivin, cyclinD1, c-myc, CD44v6, MT1-MMP, MMP2, MMP7, VEGF, Ang-1, Ang-2 and FGF-2 mRNA expression in HBx group of cells were significantly higher than those in control group.Conclusion: HBx can promote the expression of proliferation molecules, invasion molecules and angiogenesis molecules in the liver cancer cell lines.

Identification and Characterization of Hepatitis B Virus Immune Escape Mutants in Kenya

Hepatitis B Virus (HBV) infections affect about 400 million people globally and cause about 1.4 million deaths annually. The virus displays high levels of genetic variations/mutations, some of which are immune escape mutants. The prevalence of HBV infection in Kenya is high at about 8%. This study aimed at identifying and characterizing HBV immune escape mutants in Kenya. From 547 HBV sequences available in Kenya in NCBI, and HBVdb databases in July 2021, 120 full sequences were retrieved. The S gene sequences at position 1-225, which included the “a” determinant region of the gene were analyzed using various bioinformatics tools such as Bioedit software, and Emboss Cons. The clinical significance was flagged from the search of peer-reviewed journals. Forty-six HBV-positive blood donor samples were obtained from the Kenya National Blood Transfusion Services without personal identifiers, DNA extracted, and sequenced targeting positions 1 to 520 of S genes. Mutations were similarly identified from seventeen sequences after cleaning and analysis. Out of 120 sequences that were extracted from databases and analyzed, 79 different mutations were identified. Fifteen of them were of clinical importance with an occurrence frequency of at least 5% were obtained. The majority (64.6%, n = 51), with S207N and A194V being most dominant, could result in immune escape and reduced HBsAg detection signals while 24.1% (n = 19) could result in immune escape/reduced HBsAg detection signals and high probability of hepatocellular carcinoma. Most likely to occur on the amino acids Alanine, Lysine, Serine, Asparagine, and Valine in decreasing order. The most dominant genotype was found to be Genotype A (N = 10), while four sequences were Genotype D. In contrast to the in-silico studies, the sequences from HBV samples from blood donors did not demonstrate the presence of S207N and A194V mutations and all the genotypes were type A1. Only two (13.3%) samples showed the same mutations of sK122R and sT143S for both in-silico analysis and actual sequenced samples. This study did not identify G145R mutation which is the commonest mutation within the HBsAg immunodominant “a” determinant that is associated with immune escape. The concordance of mutations in “a” determinant region of HBsAg gene among various studies is minimal. The study identified new mutations (sA194Y, sS207, sA194S, sS207I, sP46A, sA194T, sS207I, sP46R, and sT143P) that had not been published before. Four (20%) of the mutations were clinically significant. These included sS207R, sT143S, sC76F and sK122R.

Hepatitis B virus infection:defective surface antigen expression and pathogenesis

Hepatitis B virus(HBV) infection is a global public health concern. HBV causes chronic infection in patients and can lead to liver cirrhosis, hepatocellular carcinoma, and other severe liver diseases. Thus, understanding HBV-related pathogenesis is of particular importance for prevention and clinical intervention. HBV surface antigens are indispensable for HBV virion formation and are useful viral markers for diagnosis and clinical assessment. During chronic HBV infection, HBV genomes may acquire and accumulate mutations and deletions, leading to the expression of defective HBV surface antigens. These defective HBV surface antigens have been found to play important roles in the progression of HBV-associated liver diseases. In this review, we focus our discussion on the nature of defective HBV surface antigen mutations and their contribution to the pathogenesis of fulminant hepatitis B. The relationship between defective surface antigens and occult HBV infection are also discussed.

Diagnostic value of gamma-glutamyltransferase/aspartate aminotransferase ratio, protein induced by vitamin K absence or antagonist II, and alpha-fetoprotein in hepatitis B virus-related hepatocellular carcinoma

BACKGROUND Researchers have investigated the diagnostic value of protein induced by vitamin K absence or antagonist II (PIVKA-II) and alpha-fetoprotein (AFP) in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC), and obtained abundant clinical diagnostic data. However, PIVKA-II and AFP have unsatisfactory specificity and sensitivity in the diagnosis of early-stage HBV-related HCC. Gamma-glutamyltransferase (γ-GT) and aspartate aminotransferase (AST) are common biomarkers for evaluating liver function, and we hypothesized that the γ-GT/AST ratio in combination with PIVKA-II and AFP would improve the diagnosis of early-stage HBV-related HCC. AIM To evaluate the diagnostic value of γ-GT/AST ratio alone or in combination with PIVKA-II and AFP in HBV-related HCC. METHODS Serum levels of γ-GT, AST, PIVKA-II, and AFP were detected and analysed in 176 patients with HBV-related HCC and in 359 patients with chronic hepatitis B. According to tumour size and serum level of HBV DNA, HBV-related HCC patients were divided into the following categories: Early-stage HCC patients, HCC patients, HBV DNA positive (HBV DNA+) HCC patients, and HBV DNA negative (HBV DNA-) HCC patients. Receiver-operating characteristic (ROC) curves were used to analyse and compare the diagnostic value of the single and combined detection of various biomarkers in different types of HBV-related HCC. RESULTS Tumour size was positively correlated with serum levels of PIVKA-II and AFP in HCC patients (r = 0.529, aP < 0.001 and r = 0.270, bP < 0.001, respectively), but there was no correlation between tumour size and the γ-GT/AST ratio (r = 0.073, P = 0.336). The areas under the receiver-operating characteristic curves (AUROCs) of the γ-GT/AST ratio in early-stage HCC patients, HBV DNA+ HCC patients and HBV DNA- HCC patients were not significantly different from that in the total HCC patients (0.754, 0.802, and 0.705 vs 0.779, respectively;P > 0.05). When PIVKA-II was combined with the γ-GT/AST ratio in the diagnosis of earlystage HCC, HCC, and HBV DNA+ HCC, the AUROCs of PIVKA-II increased, with values of 0.857 vs 0.835, 0.925 vs 0.913, and 0.958 vs 0.954, respectively. When AFP was combined with the γ-GT/AST ratio in the diagnosis of early-stage HCC, HCC, HBV DNA+ HCC, and HBV DNA- HCC, the AUROCs of AFP increased, with values of 0.757 vs 0.621, 0.837 vs 0.744, 0.868 vs 0.757, and 0.840 vs 0.828, respectively. CONCLUSION The γ-GT/AST ratio may be better than PIVKA-II and AFP in the diagnosis of early-stage HBV-related HCC, and its combination with PIVKA-II and AFP can improve the diagnostic value for HBV-related HCC.

Hepatocellular carcinoma and hepatitis B surface protein

The tumorigenesis of hepatitis B virus(HBV)-associated hepatocellular carcinoma(HCC) has been widely studied. HBV envelope proteins are important for the structure and life cycle of HBV, and these proteins are useful for judging the natural disease course and guiding treatment. Truncated and mutated pre S/S are produced by integrated viral sequences that are defective for replication. The pre S/S mutants are considered "precursor lesions" of HCC. Different pre S/S mutants induce various mechanisms of tumorigenesis, such as transactivation of transcription factors and an immune inflammatory response, thereby contributing to HCC. The pre S2 mutants and type Ⅱ "Ground Glass" hepatocytes represent novel biomarkers of HBVassociated HCC. The pre S mutants may induce the unfolded protein response and endoplasmic reticulum stress-dependent and stress-independent pathways. Treatments to inhibit hepatitis B surface antigen(HBs Ag) and damage secondary to HBs Ag or the pre S/S mutants include antivirals and antioxidants, such as silymarin, resveratrol, and glycyrrhizin acid. Methods for the prevention and treatment of HCC should be comprehensive.

Clinical utility of complex mutations in the core promoter and proximal precore regions of the hepatitis B virus genome

The core promoter and proximal precore regions are the most complex portions of the hepatitis B virus(HBV) genome. These regions cooperatively regulate viral replication and differentially regulate the synthesis of the viral proteins E,core,and X. Multiple mutations in these regions are associated with the persistency of viral infection and the development of cirrhosis and hepatocellular carcinoma(HCC). In South Korea,nearlyall HBVs are classified as HBV genotype C2; the majority of these viruses have the basal core promoter double mutation,a precore stop mutation,or both. These mutations may play a role in the alteration of viral and clinical features,and abundant and complex mutations are particularly prevalent in the core promoter and proximal precore regions. We previously demonstrated that the accumulation of ≥ 6 mutations at eight key nucleotides located in these regions(G1613A,C1653 T,T1753 V,A1762 T,G1764 A,A1846 T,G1896 A,and G1899A) is a useful marker to predict the development of HCC regardless of advanced liver disease. In addition,certain mutation combinations were predominant in cases with ≥ 4 mutations. In cases with ≤ 5 mutations,a low Hepatitis B e antigen titer(< 35 signal to noise ratio) was indicative of HCC risk. Viral mutation data of the single HBV genotype C2 suggest that the combined effect of the number and pattern of mutations in the core promoter and proximal precore regions is helpful in predicting HCC risk.

Detection of hyper-conserved regions in hepatitis B virus X gene potentially useful for gene therapy

AIM To detect hyper-conserved regions in the hepatitis B virus(HBV) X gene(HBX) 5' region that could be candidates for gene therapy.METHODS The study included 27 chronic hepatitis B treatmentnaive patients in various clinical stages(from chronic infection to cirrhosis and hepatocellular carcinoma, both HBeA g-negative and HBeA g-positive), and infected with HBV genotypes A-F and H. In a serum sample from each patient with viremia > 3.5 log IU/m L, the HBX 5' end region [nucleotide(nt) 1255-1611] was PCRamplified and submitted to next-generation sequencing(NGS). We assessed genotype variants by phylogenetic analysis, and evaluated conservation of this region by calculating the information content of each nucleotide position in a multiple alignment of all unique sequences(haplotypes) obtained by NGS. Conservation at the HBx protein amino acid(aa) level was also analyzed.RESULTS NGS yielded 1333069 sequences from the 27 samples, with a median of 4578 sequences/sample(2487-9279, IQR 2817). In 14/27 patients(51.8%), phylogenetic analysis of viral nucleotide haplotypes showed a complex mixture of genotypic variants. Analysis of the information content in the haplotype multiple alignments detected 2 hyper-conserved nucleotide regions, one in the HBX upstream non-coding region(nt 1255-1286) and the other in the 5' end coding region(nt 1519-1603). This last region coded for a conserved amino acid region(aa 63-76) that partially overlaps a Kunitz-like domain.CONCLUSION Two hyper-conserved regions detected in the HBX 5' end may be of value for targeted gene therapy, regardless of the patients' clinical stage or HBV genotype.

Hepatitis B virus,HBx mutants and their role in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is one of the leading causes of death induced by cancer in the modern world and majority of the cases are related to chronic hepatitis B virus(HBV)infection.HBV-encoded X protein(HBx)is known to play a pivotal role in the pathogenesis of viral induced HCC.HBx is a multifunctional protein of17 kDa which modulates several cellular processes by direct or indirect interaction with a repertoire of host factors resulting in HCC.HBX might interfere with several cellular processes such as oxidative stress,DNA repair,signal transduction,transcription,protein degradation,cell cycle progression and apoptosis.A number of reports have indicated that HBx is one of the most common viral ORFs that is often integrated into the host genome and its sequence variants play a crucial role in HCC.By mutational or deletion analysis it was shown that carboxy terminal of HBx has a likely role in protein-protein interactions,transcriptional transactivation,DNA repair,cell,signaling and pathogenesis of HCC.The accumulated evidence thus far suggests that it is difficult to understand the mechanistic nature of HBx associated HCC,and HBx mediated transcriptional transactivation and signaling pathways may be a major determinant.This article addresses the role of HBx in the development of HCC with particular emphasis on HBx mutants and their putative targets.

Functional interaction of endoplasmic reticulum stress and hepatitis B virus in the pathogenesis of liver diseases

Hepatitis B virus(HBV) is a non-cytopathic virus that causes acute and chronic inflammatory liver diseases,often leading to the pathogenesis of hepatocellular carcinoma(HCC). Although many studies for the roles of HBV on pathogenesis of the liver diseases,such as non-alcoholic fatty liver disease(NAFLD),hepatic inflammation,cirrhosis,and HCC,have been reported,the mechanisms are not fully understood. Endoplasmic reticulum(ER) and mitochondria have the protective mechanisms to restore their damaged function by intrinsic or extrinsic stresses,but their chronic dysfunctions are associated with the pathogenesis of the various diseases. Furthermore,HBV can affect intraor extracellular homeostasis through induction of ER and mitochondrial dysfunctions,leading to liver injury. Therefore,the mechanism by which HBV induces ER or mitochondrial stresses may be a therapeutic target for treatment of liver diseases.