Key role of hepatitis B virus mutation in chronic hepatitis B development to hepatocellular carcinoma

Molecular Characterization of Hepatitis B Virus in People Living with HIV in Rural and Peri-Urban Communities in Botswana

(1) Background: Hepatitis B virus (HBV) sequencing data are important for monitoring HBV evolution. We aimed to molecularly characterize HBV sequences from participants with HBV surface antigen-positive (HBsAg+) serology and occult hepatitis B infection (OBI+). (2) Methods: We utilized archived plasma samples from people living with human immunodeficiency virus (PLWH) in Botswana. HBV DNA was sequenced, genotyped and analyzed for mutations. We compared mutations from study sequences to those from previously generated HBV sequences in Botswana. The impact of OBI-associated mutations on protein function was assessed using the Protein Variation Effect Analyzer. (3) Results: Sequencing success was higher in HBsAg+ than in OBI+ samples [86/128 (67.2%) vs. 21/71 (29.2%)]. Overall, 93.5% (100/107) of sequences were genotype A1, 2.8% (3/107) were D3 and 3.7% (4/107) were E. We identified 13 escape mutations in 18/90 (20%) sequences with HBsAg coverage, with K122R having the highest frequency. The mutational profile of current sequences differed from previous Botswana HBV sequences, suggesting possible mutational changes over time. Mutations deemed to have an impact on protein function were tpQ6H, surfaceV194A and preCW28L. (4) Conclusions: We characterized HBV sequences from PLWH in Botswana. Escape mutations were prevalent and were not associated with OBI. Longitudinal HBV studies are needed to investigate HBV natural evolution.

The N-linked glycosylation modifications in the hepatitis B surface protein impact cellular autophagy, HBV replication, and HBV secretion

N-linked glycosylation is a pivotal post-translational modification that significantly influences various aspects of protein biology. Autophagy, a critical cellular process, is instrumental in cell survival and maintenance. The hepatitis B virus (HBV) has evolved mechanisms to manipulate this process to ensure its survival within host cells. Significantly, post-translational N-linked glycosylation in the large surface protein of HBV (LHBs) influences virion assembly, infectivity, and immune evasion. This study investigated the role of N-linked glycosylation of LHBs in autophagy, and its subsequent effects on HBV replication and secretion. LHBs plasmids were constructed by incorporating single-, double-, and triple-mutated N-linked glycosylation sites through amino acid substitutions at N4, N112, and N309. In comparison to the wild-type LHBs, N-glycan mutants, including N309Q, N4-309Q, N112-309Q, and N4-112-309Q, induced autophagy gene expression and led to autophagosome accumulation in hepatoma cells. Acridine orange staining of cells expressing LHBs mutations revealed impaired lysosomal acidification, suggesting potential blockage of autophagic flux at later stages. Furthermore, N-glycan mutants increased the mRNA expression of HBV surface antigen (HBsAg). Notably, N309Q significantly elevated HBx oncogene level. The LHBs mutants, particularly N309Q and N112-309Q, significantly enhanced HBV replication, whereas N309Q, N4-309Q, and N4-112-309Q markedly increased HBV progeny secretion. Remarkably, our findings demonstrated that autophagy is indispensable for the impact of N-linked glycosylation mutations in LHBs on HBV secretion, as evidenced by experiments with a 3-methyladenine (3-MA) inhibitor. Our study provides pioneering insights into the interplay between N-linked glycosylation mutations in LHBs, host autophagy, and the HBV life cycle. Additionally, we offer a new clue for further investigation into carcinogenesis of hepatocellular carcinoma (HCC). These findings underscore the potential of targeting either N-linked glycosylation modifications or the autophagic pathway for the development of innovative therapies against HBV and/or HCC.

Plant-based foods and hepatocellular carcinoma: A review on mechanistic understanding

Regardless of etiology, hepatocarcinogenesis is frequently preceded by a distinctive sequence of chronic necroinflammation, compensatory hepatic regeneration, development of hepatic fibrosis, and ultimately cirrhosis. The liver being central immunomodulators, closely maintains immunotolerance. Any dysregulation in this management of immunotolerance is a hallmark of chronic hepatic disease and hepatocellular carcinoma (HCC). Apart from other malignancies, hepatocellular carcinoma accounts for 90% of liver cancers. Several emerging evidences have recognized diet as lifestyle associated risk factor in HCC development. However, natural compounds have the potential to fight hepatoma aggressiveness via inhibition of cellular proliferation and modulation of oncogenic pathways. This review aimed to identify the several plant-based foods for their protective role in HCC prevention by understating the molecular mechanisms involved in inhibition of progression and proliferation of cancer. Information from relevant publications in which several plant-based foods demonstrated protective potential against HCC has been integrated as well as evaluated. For data integration, Science direct, Google scholar, and Scopus websites were used. Nutrition-based approaches in the deterrence of several cancers offer a substantial benefit to currently used medical therapies and should be implemented more often as an adjunct to first-line medical therapy. Furthermore, the inclusion of these plant-based foods (vegetables, fruits, herbs, and spices) may improve general health and decline cancer incidence.

Low host immune pressure may be associated with the development of hepatocellular carcinoma: a longitudinal analysis of complete genomes of the HBV 1762T, 1764A mutant

Background

It has been reported that hepatitis B virus (HBV) double mutations (A1762T, G1764A) are an aetiological factor of hepatocellular carcinoma (HCC). However, it is unclear who is prone to develop HCC, among those infected with the mutant. Exploring HBV quasispecies, which are strongly influenced by host immune pressure, may provide more information about the association of viral factors and HCC.

Materials and methods

Nine HCC cases and 10 controls were selected from the Long An cohort. Serum samples were collected in 2004 and 2019 from subjects with HBV double mutations and the complete genome of HBV was amplified and sequenced using next-generation sequencing (NGS).

Results

The Shannon entropy values increased from 2004 to 2019 in most cases and controls. There was no significant difference in mean intrahost quasispecies genetic distances between cases and controls. The change in the values of mean intrahost quasispecies genetic distances of the controls between 2004 and 2019 was significantly higher than that of the cases (P<0.05). The viral loads did not differ significantly between cases and controls in 2004(p=0.086) but differed at diagnosed in 2019 (p=0.009). Three mutations occurring with increasing frequency from 2004 to 2019 were identified in the HCC cases, including nt446 C→G, nt514 A→C and nt2857T→C. Their frequency differed significantly between the cases and controls (P<0.05).

Conclusions

The change in the values of mean intrahost quasispecies genetic distances in HCC was smaller, suggesting that HBV in HCC cases may be subject to low host immune pressure. Increasing viral loads during long-term infection are associated with the development of HCC. The novel mutations may increase the risk for HCC.

Mutations in the HBV PreS/S gene related to hepatocellular carcinoma in Vietnamese chronic HBV-infected patients

Background

Chronic hepatitis B virus (CHB) infection is a major health problem and leading cause of hepatocellular carcinoma (HCC) worldwide. Several point and deletion mutations on the PreS/S gene have been intensively considered associated with HCC. This study aimed to describe the characteristics of HBV PreS/S mutations in Vietnamese CHB-infected patients and their association with HCC.

Methods

This cross-sectional study was conducted from 02/2020 to 03/2021, recruited Vietnamese CHB-infected patients with HBV-DNA >3 log₁₀-copies/mL and successful PreS/S gene sequencing. Mutations were detected by direct Sanger sequencing.

Results

247 CHB-infected patients were recruited, characterized by 68.8% males, 54.7% HBV genotype B, 57.5% HBeAg positive, 23.1% fibrosis score ≥F3 and 19.8% HCC. 61.8% amino acid replacements were detected throughout the PreS1/PreS2/S genes. The most common point-mutations included N/H51Y/T/S/Q/P (30.4%), V68T/S/I (44.9%), T/N87S/T/P (46.2%) on PreS1 gene; T125S/N/P (30.8%), I150T (42.5%) on PreS2 gene; S53L (37.7%), A184V/G (39.3%), S210K/N/R/S (39.3%) on S gene. The rates of case(s) with any point-mutation on the Major Hydrophylic Region (MHR) and the "a" determinant region were 63.6% and 39.7%, respectively. Most of S point-mutations were presented with low rates such as T47A/E/V/K (9.3%), P120S/T (8.5%), G145R (2%). On multivariable analysis, males (OR = 4.51, 95%CI 1.78–11.4, p = 0.001), age≥40 (OR = 5.5, 95%CI 2.06–14.68, p = 0.001), W4P/R/Y on PreS1 (OR = 11.56, 95%CI 1.99–67.05, p = 0.006) and 4 S point-mutations as: T47A/E/V/K (OR = 3.67, 95%CI 1.19–11.29, p = 0.023), P120S/T (OR = 3.38, 95%CI 1.09–10.49, p = 0.035), S174N (OR = 29.73, 95%CI 2.12–417.07, p = 0.012), P203R (OR = 8.45, 95%CI 1.43–50.06, p = 0.019) were associated with HCC.

Conclusions

We detected 61% amino acid changes on PreS/S regions in Vietnamese CHB patients. One point-mutation at amino acid 4 on PreS1 gene and 4 point-mutations at amino acids 47, 120, 174, and 203 on S gene were associated with HCC. Further investigations are recommended to further clarify the relationship and interaction between mutations in HBV genome and HCC progression.

ViMIC: a database of human disease-related virus mutations, integration sites and cis-effects

Molecular mechanisms of virus-related diseases involve multiple factors, including viral mutation accumulation and integration of a viral genome into the host DNA. With increasing attention being paid to virus-mediated pathogenesis and the development of many useful technologies to identify virus mutations (VMs) and viral integration sites (VISs), much research on these topics is available in PubMed. However, knowledge of VMs and VISs is widely scattered in numerous published papers which lack standardization, integration and curation. To address these challenges, we built a pilot database of human disease-related Virus Mutations, Integration sites and Cis-effects (ViMIC), which specializes in three features: virus mutation sites, viral integration sites and target genes. In total, the ViMIC provides information on 31 712 VMs entries, 105 624 VISs, 16 310 viral target genes and 1 110 015 virus sequences of eight viruses in 77 human diseases obtained from the public domain. Furthermore, in ViMIC users are allowed to explore the cis-effects of virus-host interactions by surveying 78 histone modifications, binding of 1358 transcription regulators and chromatin accessibility on these VISs. We believe ViMIC will become a valuable resource for the virus research community. The database is available at http://bmtongji.cn/ViMIC/index.php.

Novel X gene point mutations in chronic hepatitis B and HBV related cirrhotic patients

INTRODUCTION

HBx is a multifunctional modulator viral protein with key roles in various biological processes such as signal transduction, transcription, proliferation, and cell apoptosis. Also, HBx has an important role in the progression of cirrhosis and hepatocellular carcinoma (HCC). This study aimed to determine mutations in X gene, enhancer II (EnhII), and basal core promoter (BCP) of genotype D of Hepatitis B Virus (HBV) in cirrhotic and chronic HBV patients.

MATERIAL AND METHODS

This cross-sectional study was performed on 68 cases with chronic HBV (cHBV) and 50 cases with HBV related cirrhosis. Serum samples were obtained for genomic DNA extraction. Semi-nested PCR was used to amplify the HBx region. Point mutations in the HBx region were detected by sequencing.

RESULT

Novel mutations were detected, including C1491G, C1500T, G1613T, and G1658T in the N-terminal of the X gene. The frequency of C1481T/G1479A, T1498C, C1500T, G1512A, A1635T, C1678T, A1727T, and A1762T/ G1764A/ C1773T was significantly higher in cirrhotic patients compared to chronically HBV infected ones. A higher rate of A1635T, C1678T, A1727T, A1762T, G1764A, and C1773T was observed in cirrhotic patients.

CONCLUSION

Our findings showed that the frequency of mutations in the basal-core promoter, enhancer II, and regulatory region of the HBx gene was more seen in cirrhotic patients than in chronic HBV cases. Novel mutations were detected in the HBx gene, causing amino acid substitutions; however, the clinical impact of these novel mutations is yet to be cleared.

Genetic Association of Interleukin-6 Polymorphism (rs1800796) with Chronic Hepatitis B Virus Infection in Chinese Han Population

Hepatitis B virus (HBV) infection is a global health care burden that can lead to chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma. We conducted this study to identify the association between interleukin-6 (IL-6) gene rs1800796 (-572G/C) polymorphism and the risk of chronic HBV infection in adults. A total of 1,048 participants including 518 cases and 530 controls were recruited for this study. The Mass Array time-of-flight mass spectrometer was applied for single-nucleotide polymorphism rs1800796 genotyping. There was a significant correlation between genotype CG in rs1800796 and chronic HBV infection in the Chinese Han population (odds ratio [OR] = 0.759, 95% confidence interval [CI]: 0.586-0.983, p = 0.04), which was also observed at allele G (OR = 0.800, 95% CI: 0.657-0.975, p = 0.02). Furthermore, significant differences in the ≤45 years old group (CC vs. CG+GG, OR = 0.616, 95% CI: 0.413-0.918, p = 0.02) and in the male group (CC vs. CG+GG, OR = 0.666, 95% CI: 0.483-0.920, p = 0.01) were found in the subgroups analysis. Our data revealed a significant association of IL-6 rs1800796 with the risk of chronic HBV infection in the Chinese Han population; meanwhile, age and gender are two coordinative risk factors, which provides new clues for the study of susceptibility of chronic HBV infection in adults.

Impact of Hepatitis B Virus Genetic Variation, Integration, and Lymphotropism in Antiviral Treatment and Oncogenesis

Chronic Hepatitis B Virus (HBV) infection poses a significant global health burden. Although, effective treatment and vaccinations against HBV are available, challenges still exist, particularly in the development of curative therapies. The dynamic nature and unique features of HBV such as viral variants, integration of HBV DNA into host chromosomes, and extrahepatic reservoirs are considerations towards understanding the virus biology and developing improved anti-HBV treatments. In this review, we highlight the importance of these viral characteristics in the context of treatment and oncogenesis. Viral genotype and genetic variants can serve as important predictive factors for therapeutic response and outcomes in addition to oncogenic risk. HBV integration, particularly in coding genes, is implicated in the development of hepatocellular carcinoma. Furthermore, we will discuss emerging research that has identified various HBV nucleic acids and infection markers within extrahepatic sites (lymphoid cells). Intriguingly, the presence of hepatocellular carcinoma (HCC)-associated HBV variants and viral integration within the lymphoid cells may contribute towards the development of extrahepatic malignancies. Improved understanding of these HBV characteristics will enhance the development of a cure for chronic HBV infection.

Detection of circulating hepatitis B virus immune escape and polymerase mutants among HBV-positive patients attending Institut Pasteur de Bangui, Central African Republic

Background

Previous studies in the Central African Republic (CAR) have reported the presence of hepatitis B virus (HBV) recombinant genotype E/D and a suspicion of immune escape mutants (IEMs), without further investigation into their impact on prevention and diagnosis. Consequently, this study investigated HBV mutations among hepatitis B surface antigen (HBsAg)-positive patients attending Institut Pasteur de Bangui in the CAR.

Methods

Sera from a total of 118 HBsAg-positive patients with no previous history of HBV treatment or vaccination at the Institut Pasteur de Bangui, were sampled between 2017 and 2019. Subsequently, the region spanning the surface and polymerase genes of HBV was amplified by PCR and sequenced. HBV sequences were genotyped/subgenotyped by phylogenetic analysis and serotyped based on predicted amino acid residues at positions s122, s127, s140, s159, and s160. They were then analyzed for HBV IEMs and polymerase mutations.

Results

The region spanning the surface and polymerase genes was successfully amplified and sequenced for 51 samples. Of the HBV sequences, 49 were genotype E and two were genotype A subgenotype A1; these were serotyped as ayw4 and ayw1, respectively. Potential IEMs sY100C, sA128V, and sM133T, and several polymerase mutants were identified.

Conclusions

This study raises awareness of the need for further studies to be conducted on a large scale to better understand HBV mutations for improved disease control and prevention strategies in the country.

Analysis of hepatitis B virus genotype and gene mutation in patients with advanced liver disease in East Kalimantan, Indonesia

Liver cirrhosis (LC) and hepatocellular carcinoma (HCC) are life-threatening conditions frequently associated with chronic hepatitis B virus (HBV) infection in Asian countries, including Indonesia. HBV genotypes and several specific mutations are associated with disease progression. To clarify the geographical variation in viral characteristics, HBV genotypes and gene mutations were investigated in patients with advanced liver disease (ALD) in Samarinda, East Kalimantan, Indonesia. Sera were collected from 41 patients with ALD at Abdul Wahab Sjahranie Hospital and HBV carriers from Red Cross Center blood bank in Samarinda, and screened for hepatitis B surface antigen and hepatitis B e-antigen. Liver function data were obtained from the medical records from each patient. HBV genotype and gene mutations were determined by polymerase chain reaction sequencing. Analysis of HBV isolates indicated that genotype B was the most frequent genotype, at 85.4 and 97.8%, followed by C, at 14.6 and 2.2%, in patients with ALD and in HBV carriers, respectively. The C1505A mutation in X region, T1753V and A1762T/G1764A mutations in the basal core promoter region and C1858T in precore (PC) region were frequent and only detected in patients with ALD (28.9, 40, 73.5 and 17.6%, respectively), whereas the G1896A mutation in the PC region was frequently detected in HBV carriers. The presence of HBV genotype B and certain HBV gene mutations were characteristic of patients with ALD in East Kalimantan.

Molecular characterization of hepatitis B virus in Bangladesh reveals a highly recombinant population

The natural history and treatment outcome of hepatitis B viruses (HBV) infection is largely dependent on genotype, subgenotype, and the presence or absence of virulence associated mutations. We have studied the prevalence of genotype and subgenotype as well as virulence and drug resistance associated mutations and prevalence of recombinant among HBV from Bangladesh. A prospective cross-sectional study was conducted among treatment naïve chronic HBV patients attending at Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh for HBV viral load assessment between June and August 2015. Systematical selected 50% of HBV DNA positive patients (every second patient) were enrolled. Biochemical and serological markers for HBV infection and whole genome sequencing (WGS) was performed on virus positive sample. Genotype, subgenotype, virulence, nucleos(t)ide analogue (NA) resistance (NAr) mutations, and the prevalence of recombinant isolates were determined. Among 114 HBV DNA positive patients, 57 were enrolled in the study and 53 HBV WGS were generated for downstream analysis. Overall, 38% (22/57) and 62% (35/57) of patients had acute and chronic HBV infections, respectively. The prevalence of genotypes A, C, and D was 18.9% (10/53), 45.3% (24/53), and 35.8% (19/53), respectively. Among genotype A, C and D isolates subgenotype A1 (90%; 9/10), C1 (87.5%; 21/24) and D2 (78.9%; 15/19) predominates. The acute infection, virulence associated mutations, and viral load was higher in the genotype D isolates. Evidence of recombination was identified in 22.6% (12/53) of the HBV isolates including 20.0% (2/10), and 16.7% (4/24) and 31.6% (6/19) of genotype A, C and D isolates, respectively. The prevalence of recombination was higher in chronic HVB patients (32.2%; 10/31 versus 9.1%; 2/22); p<0.05. NAr mutations were identified in 47.2% (25/53) of the isolates including 33.9% novel mutations (18/53). HBV genotype C and D predominated in this population in Bangladesh; a comparatively high prevalence of recombinant HBV are circulating in this setting.

A comparative study of hepatitis B virus X protein mutants K130M, V131I and KV130/131MI to investigate their roles in fibrosis, cirrhosis and hepatocellular carcinoma

Hepatitis B virus (HBV) genomic mutations A1762T, G1764A and AG1762/1764TA cause production of HBV X protein (HBx) mutants, namely K130M, V131I and KV130/131MI. These mutations are important biomarkers for the development of cirrhosis and hepatocellular carcinoma (HCC) in chronic HBV patients. This study comparatively analyses the impact of intracellular expression of HBx mutants on HCC cell line Huh7. It was found that expression of KV130/131MI induced: cell proliferation, altered expression of cell cycle regulatory genes in favour of cell proliferation, intracellular reactive oxygen species (ROS) production and mitochondrial depolarization. KV130/131MI may be directly involved in host cell proliferation and hepatocarcinogenesis via altering expression of cell cycle regulatory genes. KV130/131MI may also play pivotal roles in fibrosis and cirrhosis via inducing ROS production and mitochondrial depolarization. Furthermore, these might be the possible reasons for higher occurrence of AG1762/1764TA as compared to A1762T and G1764A in cirrhosis and HCC patients.

Molecular characterization of hepatitis B virus in Vietnam

Background

Hepatitis B virus (HBV) infection is a major public health problem globally. HBV genotypes and subgenotypes influence disease transmission, progression, and treatment outcome. A study was conducted among treatment naive chronic HBV patients in southern Vietnam to determine the genotypes and subgenotypes of HBV.

Methods

A prospective, exploratory study was conducted among treatment naïve chronic HBV patients attending at the Hospital for Tropical Diseases, in Ho Chi Minh City, Vietnam during 2012, 2014 and 2016. HBV DNA positive samples (systematically selected 2% of all treatment naïve chronic patients during 2012 and 2014, and 8% of all treatment naïve chronic patients during 2016) were subjected to whole genome sequencing (WGS) either by Sanger or Illumina sequencing. WGS was used to define genotype, sub-genotype, recombination, and the prevalence of drug resistance and virulence-associated mutations.

Results

One hundred thirty five treatment naïve chronic HBV patients including 18 from 2012, 24 from 2014, and 93 from 2016 were enrolled. Of 135 sequenced viruses, 72.6% and 27.4% were genotypes B and C respectively. Among genotype B isolates, 87.8% and 12.2% were subgenotypes B4 and B2 respectively. A G1896A mutation in the precore gene was present in 30.6% of genotype B isolates. The genotype C isolates were all subgenotype C1 and 78.4% (29/37) of them had at least one basal core promoter (BCP) mutation. A1762T and G1764 T mutations and a double mutation (A1762T and G1764 T) in the BCP region were significantly more frequent in genotype C1 isolates (p < 0.001).

Conclusion

HBV genotype B including subgenotype B4 is predominant in southern Vietnam. However, one fourth of the chronic HBV infections were caused by subgenotype C1.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2697-x) contains supplementary material, which is available to authorized users.

Novel HBsAg mutations correlate with hepatocellular carcinoma, hamper HBsAg secretion and promote cell proliferation in vitro

Background

An impaired HBsAg-secretion can increase HBV oncogenic-properties. Here, we investigate genetic-determinants in HBsAg correlated with HBV-induced hepatocellular carcinoma (HCC), and their impact on HBsAg-secretion and cell-proliferation.

Methods

This study included 128 chronically HBV-infected patients: 23 with HCC (73.9% D; 26.1% A HBV-genotype), and 105 without cirrhosis/HCC (72.4% D, 27.6% A) as reference-group. The impact of mutations on HBsAg-secretion was assessed by measuring the ratio [secreted/intracellular HBsAg] until day 5 post-transfection. The impact of mutations on cell-cycle advancement was assessed by flow-cytometry.

Results

Two HBsAg mutations significantly correlated with HCC: P203Q (17.4% [4/23] in HCC vs 1.0% [1/105] in non-HCC, P=0.004); S210R (34.8% [8/23] in HCC vs 3.8% [4/105] in non-HCC, P <0.001); P203Q+S210R (17.4% [4/23] in HCC vs 0% [0/110] in non-HCC, P=0.001). Both mutations reside in trans-membrane C-terminal domain critical for HBsAg-secretion. In in-vitro experiments, P203Q, S210R and P203Q+S210R significantly reduced the ratio [secreted/intracellular HBsAg] compared to wt at each time-point analysed (P <0.05), supporting an impaired HBsAg-secretion. Furthermore, P203Q and P203Q+S210R increased the percentage of cells in S-phase compared to wt, indicating cell-cycle progression (P203Q:26±13%; P203Q+S210R:29±14%; wt:18%±9, P <0.01. Additionally, S210R increased the percentage of cells in G2/M-phase (26±8% for wt versus 33±6% for S210R, P <0.001).

Conclusions

Specific mutations in HBsAg C-terminus significantly correlate with HBV-induced HCC. They hamper HBsAg-secretion and are associated with increased cellular proliferation, supporting their involvement in HCC-development. The identification of viral genetic markers associated with HCC is critical to identify patients at higher HCC-risk that may deserve intensive liver monitoring, and/or early anti-HBV therapy.

Gab2 mediates hepatocellular carcinogenesis by integrating multiple signaling pathways

Our previous studies have found that Growth factor receptor-bound protein 2-associated binding protein 2 (Gab2)-a docking protein-governs the development of fatty liver disease. Here, we further demonstrate that Gab2 mediates hepatocarcinogenesis. Compared with a faint expression in para-carcinoma tissue, Gab2 was highly expressed in ∼60-70% of human hepatocellular carcinoma (HCC) specimens. Deletion of Gab2 dramatically suppressed diethylnitrosamine-induced HCC in mice. The oncogenic effects of Gab2 in HepG2 cells were promoted by Gab2 overexpression but were rescued by Gab2 knockdown. Furthermore, Gab2 knockout in HepG2 cells restrained cell proliferation, migration and tumor growth in nude mice. Signaling pathway analysis with protein kinase inhibitors demonstrated that oncogenic regulation by Gab2 in hepatic cells involved multiple signaling molecules, including ERK, Akt, and Janus kinases (Jaks), especially those that mediate inflammatory signaling. IL-6 signaling was increased by Gab2 overexpression and impaired by Gab2 deletion via regulation of Jak2 and signal transducer and activator of transcription 3 phosphorylation and the expression of downstream genes, such as Bcl-2 (B-cell lymphoma 2), c-Myc, MMP7 (matrix metalloproteinase-7), and cyclin D1in vitro and in vivo These data indicate that Gab2 mediates the pathologic progression of HCC by integrating multiple signaling pathways and suggest that Gab2 might be a powerful therapeutic target for HCC.-Cheng, J., Zhong, Y., Chen, S., Sun, Y., Huang, L., Kang, Y., Chen, B., Chen, G., Wang, F., Tian, Y., Liu, W., Feng, G.-S., Lu, Z. Gab2 mediates hepatocellular carcinogenesis by integrating multiple signaling pathways.

Effect of hepatic steatosis on the progression of chronic hepatitis B: A prospective cohort and in vitro study

Aim

To characterize the effect of hepatic steatosis (HS) on the progression of chronic hepatitis B.

Methods

A total of 162 chronic hepatitis B (CHB) patients confirmed by liver biopsy were involved in this study. All subjects were prospectively followed-up for 5 years in real-life clinical practice. Fibrosis stage was determined using aspartate aminotransferase-to-platelet ratio index (APRI). The end-point was cirrhosis, liver cancer or death. The effects of steatosis on the biological behavior of hepatocellular carcinoma cells were investigated using oleic acid-induced lipid accumulation in HepG₂, HLE, PLC, and SMMC-7721 cells.

Results

Mean age, body mass index, and serum cholesterol were significantly higher in CHB patients with HS than those without HS at baseline (p< 0.05). The APRI was lower in patients without HS at baseline (p<0.05). Compared to patients with HS, APRI of patients without HS decreased significantly during the follow-up period (p<0.05). The 5-year cumulative incidence of cirrhosis were 4.17% and 5.19% in patients without and with HS, respectively (p>0.05). The multivariate analysis showed that older (RR 1.07, 95% CI 0.996-1.149, p = 0.065) and S3 stage of liver fibrosis (RR 3.50, 95% CI 0.812–15.117, p=0.093) were risk factors for the progression to cirrhosis. In vitro, cell steatosis promoted proliferation and migration of HCC cells and conferred cell cycle at S phase.

Conclusion

The older and S3 stage of fibrosis may be risk factors for progression to cirrhosis in CHB patients with HS. HS may aggravate liver disease, promoting HCC progression.

Modulatory effects of rutin on the expression of cytochrome P450s and antioxidant enzymes in human hepatoma cells

Expression of a drug and xenobiotic metabolizing enzymes, cytochrome P450s (CYPs), and antioxidant enzymes can be modulated by various factors. The flavonoid rutin was investigated for its anti-carcinogen and protective effects as well as modulatory action on CYPs and phase II enzymes in human hepatocellular carcinoma cells. Rutin inhibited proliferation of HEPG2 cells in a dose-dependent manner with the IC50 value of 52.7 μmol L-1 and invasion of HEPG2 cells (21.6 %, p = 0.0018) and colony formation of those invaded cells (57.4 %, p < 0.0001). Rutin treatment also significantly increased early/late-stage apoptosis in HEPG2 cells (28.9 %, p < 0.001). Treatment by rutin significantly inhibited protein expressions of cytochrome P450-dependent CYP3A4 (75.3 %, p < 0.0001), elevated CYP1A1 enzymes (1.7-fold, p = 0.0084) and increased protein expressions of antioxidant and phase II reaction catalyzing enzymes, NQO1 (2.42-fold, p < 0.0001) and GSTP1 (2.03-fold, p < 0.0001). Besides, rutin treatment significantly inhibited mRNA expression of CYP3A4 (73.2 %, p=0.0014). Also, CYP1A1, NQO1 and GSTP1 mRNA expressions were significantly increased 2.77-fold (p = 0.029), 4.85- fold (p = 0.0051) and 9.84-fold (p < 0.0001), respectively.

Mutation in the S gene a determinant of the hepatitis B virus associated with concomitant HBsAg and anti-HBs in a population in Northeastern Brazil

Mutations in the a determinant of S gene may develop co-existence of hepatitis B surface antigen (HBsAg) and antibodies to HBsAg (anti-HBs) in the serum of infected hepatitis B virus (HBV) individuals. Mutations in this region may change the antigenicity of HBsAg, which in turn, lead to escape of neutralizing action of anti-HBs antibodies. This study identified individuals with concomitant HBsAg and anti-HBs serological markers in individuals of Maranhão, Northeastern Brazil. Samples from a population-based study were evaluated for HBsAg, anti-HBs, and anti-HBc, and those that tested positive for simultaneous HBsAg and anti-HBs were submitted to HBV DNA quantification and S gene characterization by Sanger sequencing. Mutations were investigated in the a determinant located in major hydrophilic region (MHR) of the S gene. Among 3,984 samples analyzed, 92 (2.3%) were positive for HBsAg and three had the atypical HBsAg and anti-HBs-positive profile (3.26%). The frequency of HBsAg and anti-HBs co-existence was similar to previous studies. Only one individual harbored mutation in the S gene a determinant associated with this profile. Little is known about this phenomenon; however, studies as ours may contribute for future enlightenment of this important issue. J. Med. Virol. 89:458-462, 2017. © 2016 Wiley Periodicals, Inc.

Precore/core region mutations of hepatitis B virus related to clinical severity

Despite the availability of an effective vaccine, hepatitis B virus (HBV) infection remains a major health problem, with more than 350 million chronically infected people worldwide and over 1 million annual deaths due to cirrhosis and liver cancer. HBV mutations are primarily generated due both to a lack of proofreading capacity by HBV polymerase and to host immune pressure, which is a very important factor for predicting disease progression and therapeutic outcomes. Several types of HBV precore/core (preC/C) mutations have been described to date. The host immune response against T cells drives mutation in the preC/C region. Specifically, preC/C mutations in the MHC class II restricted region are more common than in other regions and are significantly related to hepatocellular carcinoma. Certain mutations, including preC G1896A, are also significantly related to HBeAg-negative chronic infection. This review article mainly focuses on the HBV preC/C mutations that are related to disease severity and on the HBeAg serostatus of chronically infected patients.

Mechanisms of hepatocellular carcinoma and challenges and opportunities for molecular targeted therapy

The incidence and mortality of hepatocellular carcinoma (HCC) have fallen dramatically in China and elsewhere over the past several decades. Nonetheless, HCC remains a major public health issue as one of the most common malignant tumors worldwide and one of the leading causes of death caused by cancer in China. Hepatocarcinogenesis is a very complex biological process associated with many environmental risk factors and factors in heredity, including abnormal activation of cellular and molecular signaling pathways such as Wnt/β-catenin, hedgehog, MAPK, AKT, and ERK signaling pathways, and the balance between the activation and inactivation of the proto-oncogenes and anti-oncogenes, and the differentiation of liver cancer stem cells. Molecule-targeted therapy, a new approach for the treatment of liver cancer, blocks the growth of cancer cells by interfering with the molecules required for carcinogenesis and tumor growth, making it both specific and selective. However, there is no one drug completely designed for liver cancer, and further development in the research of liver cancer targeted drugs is now almost stagnant. The purpose of this review is to discuss recent advances in our understanding of the molecular mechanisms underlying the development of HCC and in the development of novel strategies for cancer therapeutics.