HBV-related Hepatocarcinogenesis Research Articles

Development of hepatocellular carcinoma in treated and untreated patients with chronic hepatitis B virus infection.

Hepatitis B virus (HBV) is responsible for more than 50% of hepatocellular carcinoma (HCC) in HBV hyperendemic areas, such as the Asia-Pacific region. Several hepatitis B viral factors are involved in HBV-related hepatocarcinogenesis. Hepatitis B viral load is the most important risk factor of HCC development. In addition, HBV integration, HBV genotype C, and core-promoter mutations are also associated with a risk of HCC development. For untreated chronic hepatitis B (CHB) patients, the estimated HCC incidence rates per 100 patient-years were 0.03-0.17 in inactive carriers, 0.07-0.42 in asymptomatic carriers, 0.12-0.49 in chronic hepatitis, and 2.03-3.37 in cirrhosis. Complementary to HBV DNA, serum levels of the hepatitis B surface antigen and hepatitis B core-related antigen (HBcrAg) can predict the occurrence of HCC for untreated patients with low and intermediate viral loads, respectively. For patients receiving antiviral therapy, the risks of HCC occurrence 40-60% lower than those for untreated patients. Patients treated with residual detectable HBV DNA or intrahepatic cccDNA still have a risk of HCC. Serum levels of HBcrAg, M2BPGi and fibrosis-4 are predictive of the risk of HCC development in treated patients. Several well-developed HCC risk scores can help clinicians identify high-risk CHB patients for HCC surveillance, regardless of treatment status. These strategies can help minimize the threat of HCC and prolong survival in CHB patients.

Elevated neutrophil extracellular traps by HBV-mediated S100A9-TLR4/RAGE-ROS cascade facilitate the growth and metastasis of hepatocellular carcinoma.

Neutrophil extracellular traps (NETs) are considered significant contributors to cancer progression, especially metastasis. However, it is still unclear whether NETs are involved in hepatitis B virus (HBV)-related hepatocarcinogenesis and have potential clinical significance during evaluation and management for hepatocellular carcinoma (HCC). In this study, we aimed to investigate the functional mechanism of NETs in HBV-related hepatocarcinogenesis and their clinical significance. A total of 175 HCC patients with and without HBV infection and 58 healthy controls were enrolled in this study. NETs were measured in tissue specimens, freshly isolated neutrophils and blood serum from these patients, and the correlation of circulating serum NETs levels with malignancy was evaluated. The mechanism by which HBV modulates NETs formation was explored using cell-based studies. In addition, in vitro and in vivo experiments were further performed to clarify the functional mechanism of NETs on the growth and metastasis of HCC. We observed an elevated level of NETs in blood serum and tissue specimens from HCC patients, especially those infected with HBV. NETs facilitated the growth and metastasis of HCC both in vitro and in vivo, which were mainly dominated by increased angiogenesis, epithelial-mesenchymal transition (EMT)-related cell migration, matrix metalloproteinases (MMPs)-induced extracellular matrix (ECM) degradation and NETs-mediated cell trapping. Inhibition of NETs generation by DNase 1 effectively abrogated the NETs-aroused HCC growth and metastasis. In addition, HBV-induced S100A9 accelerated the generation of NETs, which was mediated by activation of toll-like receptor (TLR4)/receptor for advanced glycation end products (RAGE)-reactive oxygen species (ROS) signaling. Further, circulatory NETs were found to correlate with viral load, TNM stage and metastasis status in HBV-related HCC, and the identified NETs could predict extrahepatic metastasis, with an area under the ROC curve (AUC) of 0.83 and 90.3% sensitivity and 62.8% specificity at a cutoff value of 0.32. Our findings indicated that activation of RAGE/TLR4-ROS signaling by HBV-induced S100A9 resulted in abundant NETs formation, which subsequently facilitated the growth and metastasis of HCC cells. More importantly, the identified circulatory NETs exhibited potential as an alternative biomarker for predicting extrahepatic metastasis in HBV-related HCC.

Intracellular antibody targeting HBx suppresses invasion and metastasis in hepatitis B virus-related hepatocarcinogenesis via protein phosphatase 2A-B56γ-mediated dephosphorylation of protein kinase B.

Hepatitis B virus X (HBx) is closely associated with HBV-related hepatocarcinogenesis via the inactivation of tumour suppressors. Protein phosphatase 2A (PP2A) regulatory subunit B56 gamma (B56γ), as a tumour suppressor, plays a critical role in regulating cellular phosphorylation signals via dephosphorylation of signalling proteins. However, the underlying mechanism that B56γ involved in regulating HBx-associated hepatocarcinogenesis phenotypes and mediating anti-HBx antibody-mediated tumour suppression remains unknown. We used bioinformatics analysis, paired HCC patient specimens, HBx transgenic (HBx-Tg) mice, xenograft nude mice, HBV stable replication in the HepG2.2.15 cells, and anti-HBx antibody intervention to systematically evaluate the biological function of protein kinase B (AKT) dephosphorylation through B56γ in HBx-associated hepatocarcinogenesis. Bioinformatics analysis revealed that AKT, matrix metalloproteinase 2 (MMP2), and MMP9 were markedly upregulated, while cell migration and viral carcinogenesis pathways were activated in HBV-infected liver tissues and HBV-associated HCC tissues. Our results demonstrated that HBx-expression promotes AKT phosphorylation (p-AKTThr308/Ser473 ), mediating the migration and invasion phenotypes in vivo and in vitro. Importantly, in clinical samples, HBx and B56γ were downregulated in HBV-associated HCC tumour tissues compared with peritumor tissues. Moreover, intervention with site-directed mutagenesis (AKTT308A , AKTS473A ) of p-AKTThr308/Ser473 mimics dephosphorylation, genetics-based B56γ overexpression, and intracellular anti-HBx antibody inhibited cell growth, migration, and invasion in HBx-expressing HCC cells. Our results demonstrated that B56γ inhibited HBV/HBx-dependent hepatocarcinogenesis by regulating the dephosphorylation of p-AKTThr308/Ser473 in HCC cells. The intracellular anti-HBx antibody and the activator of B56γ may provide a multipattern chemopreventive strategy against HBV-related HCC.

CA10 is associated with HBV-related hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is the main threat for the patients infected with hepatitis B virus (HBV), but the oncogenic mechanism of HBV-related HCC is still controversial. Previously, we have found that several HBV surface gene (HBS) non-sense mutations are oncogenic. Among these mutations, sW182* was found to have the most potent oncogenicity. In this study, we found that Carbonic Anhydrase X (CA10) level was specifically increased in sW182* mutant-expressing cells. CA10 overexpression was also associated with HBS nonsense mutation in HBV-related HCC tumor tissues. Transformation and tumorigenesis assays revealed that CA10 had significant oncogenic activity. In addition, CA10 overexpression resulted in dysregulation of apoptosis-related proteins, including Mcl-1, Bcl-2, Bcl-xL and Bad. While searching for the regulatory mechanism of CA10, miR-27b was found to downregulate CA10 expression by regulating its mRNA degradation and its expression was decreased in sW182* mutant cells. Moreover, CA10 overexpression was associated with down-regulation of miR-27b in human HBV-related HCC tumor tissues with sW182* mutation. Therefore, induction of the expression of CA10 through repression of miR-27b by sW182* might be one mechanism involved in HBS mutation-related hepatocarcinogenesis.

PreS1 Antigen of HBV Down-Regulates MHC-Ⅰ on the Surface of Hepatocytes and Promotes Hepatocarcinogenesis

To explore the internal mechanism of hepatocellular carcinoma (HCC) induced by chronic hepatitis B virus (HBV) infection. L02, HepG2 and Huh7 cells stably overexpressing HBV preS1 antigen were analyzed by flow cytometry, qRT-PCR and tumorigenesis in nude mice to evaluate the effect of preS1 antigen in HBV-related hepatocarcinogenesis. Our results showed that the expression of cancer stem cell (CSCs) related factors and cell surface markers in preS1 overexpressing cells were up-regulated, and the tumorigenicity of these cells was enhanced in nude mice. In addition, preS1 overexpression could down-regulate the expression of major histocompatibility complex Ⅰ (MHC-Ⅰ). The expression of MHC-Ⅰ on the cell surface could be restored by adding interferon gamma (IFN-γ) in the process of cell culturing and the tumorigenicity of cells in nude mice could thus be reduced. Based on the above results, we believe that preS1 is a carcinogen of HBV and that it promotes the formation of liver cancer through down regulating MHC-Ⅰ on the surface of hepatocytes.

Molecular Mechanisms and Animal Models of HBV-Related Hepatocellular Carcinoma: With Emphasis on Metastatic Tumor Antigen 1.

Hepatocellular carcinoma (HCC) is an important cause of cancer death worldwide, and hepatitis B virus (HBV) infection is a major etiology, particularly in the Asia-Pacific region. Lack of sensitive biomarkers for early diagnosis of HCC and lack of effective therapeutics for patients with advanced HCC are the main reasons for high HCC mortality; these clinical needs are linked to the molecular heterogeneity of hepatocarcinogenesis. Animal models are the basis of preclinical and translational research in HBV-related HCC (HBV-HCC). Recent advances in methodology have allowed the development of several animal models to address various aspects of chronic liver disease, including HCC, which HBV causes in humans. Currently, multiple HBV-HCC animal models, including conventional, hydrodynamics-transfection-based, viral vector-mediated transgenic, and xenograft mice models, as well as the hepadnavirus-infected tree shrew and woodchuck models, are available. This review provides an overview of molecular mechanisms and animal models of HBV-HCC. Additionally, the metastatic tumor antigen 1 (MTA1), a cancer-promoting molecule, was introduced as an example to address the importance of a suitable animal model for studying HBV-related hepatocarcinogenesis.

The Matrisome Genes From Hepatitis B-Related Hepatocellular Carcinoma Unveiled.

Chronic hepatitis B virus (HBV) infection changes the composition of the extracellular matrix (ECM) and enables the onset and progression of hepatocellular carcinoma (HCC). The ensemble of ECM proteins and associated factors is a major component of the tumor microenvironment. Our aim was to unveil the matrisome genes from HBV‐related HCC. Transcriptomic and clinical profiles from 444 patients with HBV‐related HCC were retrieved from the Gene Expression Omnibus (GEO) and Cancer Genome Atlas (TCGA) repositories. Matrisome genes associated with HBV‐related hepatocarcinogenesis, matrisome gene modules, HCC subgroups, and liver‐specific matrisome genes were systematically analyzed, followed by identification of their biological function and clinical relevance. Eighty matrisome genes, functionally enriched in immune response, ECM remodeling, or cancer‐related pathways, were identified as associated with HBV‐related HCC, which could robustly discriminate HBV‐related HCC tumor from nontumor samples. Subsequently, four significant matrisome gene modules were identified as showing functional homogeneity linked to cell cycle activity. Two subgroups of patients with HBV‐related HCC were classified based on the highly correlated matrisome genes. The high‐expression subgroup (15.0% in the TCGA cohort and 17.9% in the GEO cohort) exhibited favorable clinical prognosis, activated metabolic activity, exhausted cell cycle, strong immune infiltration, and lower tumor purity. Four liver‐specific matrisome genes (F9, HPX [hemopexin], IGFALS [insulin‐like growth‐factor‐binding protein, acid labile subunit], and PLG [plasminogen]) were identified as involved in HBV‐related HCC progression and prognosis. Conclusion: This study identified the expression and function of matrisome genes from HBV‐related hepatocarcinogenesis, providing major insight to understand HBV‐related HCC and develop potential therapeutic opportunities.

Anti-oncogene PTPN13 inactivation by hepatitis B virus X protein counteracts IGF2BP1 to promote hepatocellular carcinoma progression

Hepatitis B x protein (HBx) affects cellular protein expression and participates in the tumorigenesis and progression of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Metabolic reprogramming contributed to the HCC development, but its role in HBV-related HCC remains largely unclear. Tyrosine-protein phosphatase nonreceptor type 13 (PTPN13) is a significant regulator in tumor development, however, its specific role in hepatocarcinogenesis remains to be explored. Here, we found that decreased PTPN13 expression was associated with HBV/HBx. Patients with low PTPN13 expression showed a poor prognosis. Functional assays revealed that PTPN13 inhibited proliferation and tumorigenesis in vitro and in vivo. Further mechanistic studies indicated that HBx inhibited PTPN13 expression by upregulating the expression of DNMT3A and interacting with DNMT3A. Furthermore, we found that DNMT3A bound to the PTPN13 promoter (−343 to −313 bp) in an epigenetically controlled manner associated with elevated DNA methylation and then inhibited PTPN13 transcription. In addition, we identified IGF2BP1 as a novel PTPN13-interacting gene and demonstrated that PTPN13 influences c-Myc expression by directly and competitively binding to IGF2BP1 to decrease the intracellular concentration of functional IGF2BP1. Overexpressing PTPN13 promoted c-Myc mRNA degradation independent of the protein tyrosine phosphatase (PTP) activity of PTPN13. Importantly, we discovered that the PTPN13-IGF2BP1-c-Myc axis was important for cancer cell growth through promoting metabolic reprogramming. We verified the significant negative correlations between PTPN13 expression and c-Myc, PSPH, and SLC7A1 expression in clinical HCC tissue samples. In summary, our findings demonstrate that PTPN13 is a novel regulator of HBV-related hepatocarcinogenesis and may play an important role in HCC. PTPN13 may serve as a prognostic marker and therapeutic target in HBV-related HCC patients.

1013P PTPN13 inactivation by hepatitis B virus X regulates metabolic reprogramming for hepatocellular carcinoma progression

Hepatitis B x protein (HBx) participates in the tumorigenesis and progression of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). PTPN13 is a significant regulator in tumor development, however, its specific role in hepatocarcinogenesis remains to be explored. We herein explore the function and mechanism of PTPN13-triggered metabolic reprogramming in HBV related hepatocarcinogenesis. QRT-PCR, Western blotting, and immunohistochemistry were used to analyze HCC cell lines, and human and mouse HCC tumor tissues, and to correlate PTPN13 expression with patient prognosis. The underlying regulatory mechanisms were studied with both ex vivo analyses and vitro experiments, such as immunoprecipitation, Chromatin immunoprecipitation and Electrophoretic mobility shift assay, mammalian two-hybrid system and RNA-binding protein immunoprecipitation. Decreased PTPN13 expression was associated with HBV/HBx. Patients with low PTPN13 expression showed a poor prognosis. Functional assays revealed that PTPN13 inhibited proliferation and tumorigenesis. Further mechanistic studies indicated that HBx inhibited PTPN13 expression by upregulating the expression of DNMT3A and interacting with DNMT3A. Furthermore, we found that DNMT3A bound to the PTPN13 promoter (-343∼-313 bp) in an epigenetically controlled manner associated with elevated DNA methylation and then inhibited PTPN13 transcription. Additionally, we identified IGF2BP1 as a novel PTPN13-interacting gene and demonstrated that PTPN13 influences c-Myc expression by directly and competitively binding to IGF2BP1 to decrease the intracellular concentration of IGF2BP1. Importantly, we discovered that the PTPN13-IGF2BP1-c-Myc axis was important for cancer cell growth through promoting metabolic reprogramming. We verified the significant negative correlations between PTPN13 expression and c-Myc, PSPH, and SLC7A1 expression in HCC tissues. PTPN13 is a novel regulator of HBV-related hepatocarcinogenesis and may play an important role in HCC. PTPN13 may serve as a prognostic marker and therapeutic target in HBV-related HCC patients.

Role of microRNA-210-3p in hepatitis B virus-related hepatocellular carcinoma.

Hepatitis B virus (HBV)-related hepatocarcinogenesis is not necessarily associated with the liver fibrotic stage and is occasionally seen at early fibrotic stages. MicroRNAs (miRNAs) are essentially 18- to 22-nucleotide-long endogenous noncoding RNAs. Aberrant miRNA expression is a common feature of various human cancers. The aberrant expression of specific miRNAs has been shown in hepatocellular carcinoma (HCC) tissue compared with nontumor tissue. Thus, we examined targetable miRNAs as a potential new biomarker related to the high risk of HBV-related hepatocarcinogenesis, toward the prevention of cancer-related deaths. HCC tissue samples from 29 patients who underwent hepatectomy at our hospital in 2002-2013 were obtained. We extracted the total RNA and analyzed it by microRNA array, real-time RT-PCR, and three comparisons: 1) HBV-related HCC and adjacent nontumor tissue, 2) HCV-related HCC and adjacent nontumor tissue, and 3) non-HBV-, non-HCV-related HCC and adjacent nontumor tissue. We also performed a functional analysis of miRNAs specific for HBV-related HCC by using HBV-positive HCC cell lines. MiR-210-3p expression was significantly increased only in the HBV-related HCC tissue samples. MiR-210-3p expression was upregulated, and the levels of its target genes were reduced in the HBV-positive HCC cells. The inhibition of miR-210-3p enhanced its target gene expression in the HBV-positive HCC cells. In addition, miR-210-3p regulated the HBx expression in HBV-infected Huh7/NTCP cells. The enhanced expression of miR-210-3p was detected specifically in HBV-related HCC and regulated various target genes, including HBx in the HBV-positive HCC cells. MiR-210-3p might, thus, be a new biomarker for the risk of HBV-related HCC.NEW & NOTEWORTHY Our present study demonstrated that miR-210-3p is the only microRNA with enhanced expression in HBV-related HCC, and the enhanced expression of miR-210-3p upregulates HBx expression. Therefore, miR-210-3p might be a pivotal biomarker of HBV-related hepatocarcinogenesis, and the inhibition of miR-210-3p could prevent inducing hepatocarcinogenesis related to HBV infection.

NGS-based profiling reveals a critical contributing role of somatic D-loop mtDNA mutations in HBV-related hepatocarcinogenesis.

Somatic mutations of mitochondrial DNA (mtDNA) have been extensively identified mainly by traditional Sanger sequencing technology in various cancer types. However, low detection sensitivity of traditional methods greatly limits the comprehensive profiling of mtDNA somatic mutations in cancers, especially in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). Moreover, the functional roles of mtDNA mutation in HBV-related hepatocarcinogenesis have not been systematically revealed. Next-generation sequencing (NGS) platform was applied to profile the somatic mtDNA mutations of HCC and paired paratumor (non-HCC) tissues from a large cohort of 156 HBV-HCC patients. Our data revealed the common existence of mtDNA mutation in both inflammatory and cancer tissues with significantly different mutation pattern. The mutation density (mutation number/region length) of D-loop region was much higher than that of other regions in both HCC and non-HCC tissues. Unexpectedly, the average mutation number in D-loop region of HCC tissues was significantly less than that of non-HCC tissues. In contrast, the heteroplasmy level of D-loop region mutations was significantly increased in HCC tissues, implying that the D-loop mutations might be positively selected in HCC tissues. Furthermore, our results indicated that the patients with D-loop mutations had a significantly lower mtDNA copy number and were more likely to relapse. In vitro experiments demonstrated that proliferation, invasion and metastasis ability of HCC cells with D-loop region mutations were significantly higher than those without D-loop region mutations. These results emphasize the critical contributing role of somatic mtDNA D-loop mutations in HBV-related hepatocarcinogenesis.

Genomic landscape of HBV-related hepatocellular carcinoma in south China patients with high mutational frequency of TP53 and TERT promoter.

e15670 Background: Development of hepatocellular carcinoma (HCC) is a complex process with accumulations of polygene abnormalities and multi-pathway misregulation. Hepatitis B virus (HBV) exposure can cause liver damage and promote hepatocarcinogenesis via various biological effects. We aimed to investigate the molecular mechanisms underlying the etiology of HBV-related HCC development, and provide new insights into novel molecular targets. Methods: 84 HBV-positive HCC patients from Guangxi Province, South China, who underwent hepatic resection, were enrolled in this study. Genomic alterations were analyzed in pair-matched tumor and adjacent normal tissue using a hybridization capture-based next-generation sequencing (NGS) assay targeting 422 cancer-relevant genes. Results: In total, 691 somatic mutations, 166 copy number variations and 10 gene fusions were detected in 81 (96.4%) of 84 tumor samples. The most commonly mutated gene is TP53 in this cohort (84% of the patients), which is much higher than its frequency in the reported overall HCC patients. TERT promoter has somatic mutations in 32% of the patients, reactivation of which has been implicated in multiple cancer types. Dysfunction in the cell cycle control pathway (TP53, RB1, CCND1, CDKN2A and CCNE1) was dominant, followed by PI3K/AKT cascade (PIK3CA, AKT3, MTOR, TSC1 and TSC2), while genes of WNT signaling pathway (CTNNB1, APC and AXIN2) were mutated at a lower frequency. In addition, 69 variants in 25 DNA damage repair (DDR) genes were identified in 37 (45.7%) patients. Patients with DDR mutations had a higher tumor mutation burden (TMB) than those without DDR mutations. Conclusions: This study revealed a unique genomic landscape of HBV-related HCC. Besides TP53 being the highest mutated gene, a significant fraction of patients was identified with TERT promoter mutations, suggesting that TERT may play a role in HBV-related hepatocarcinogenesis as a novel molecular marker. Furthermore, the most common biological processes affected by HBV status in HCC were cell cycle control, PI3K/AKT and WNT signaling pathways. The possible synergistic effects of HBV in hepatocarcinogenesis warrant further investigations.

Stabilization of E2-EPF UCP protein is implicated in hepatitis B virus-associated hepatocellular carcinoma progression

Hepatitis B virus (HBV) X protein (HBx) is associated with hepatocarcinogenesis. E2-EPF ubiquitin carrier protein (UCP) catalyzes ubiquitination of itself and von Hippel–Lindau protein (pVHL) for degradation and associates with tumor growth and metastasis. However, it remains unknown whether HBx modulates the enzyme activity of UCP and thereby influences hepatocarcinogenesis. Here, we show that UCP is highly expressed in liver tissues of HBx-transgenic mice, but not non-transgenic mice. UCP was more frequently expressed in HBV-positive liver cancers than in HBV-negative liver cancers. HBx binds to UCP specifically and serotype independently, and forms a ternary complex with UCP and pVHL. HBx inhibits self-ubiquitination of UCP, but enhances UCP-mediated pVHL ubiquitination, resulting in stabilization of hypoxia-inducible factor-1α and -2α. HBx and UCP stabilize each other by mutually inhibiting their ubiquitination. HBx promotes cellular proliferation and metastasis via UCP. Our findings suggest that UCP plays a key role in HBV-related hepatocarcinogenesis.

HBx-induced S100A9 in NF-\u03baB dependent manner promotes growth and metastasis of hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is associated with hepatitis B virus (HBV) infection. Myeloid-specific S100 proteins (S100s), namely, S100A8, S100A9 and S100A12, have been recently recognized as newly discovered damage-associated molecular patterns (DAMPs) that are correlated with progression in pathogen of infectious diseases. However, whether S100s are regulated by HBV and involved in HBV-related hepatocarcinogenesis are still unclear. Here, we found that all expression levels of myeloid-specific S100s (S100A8, S100A9 and S10012) were elevated in serum and tissue samples from HCC patients. Expression of S100A9 but not S100A8 and S10012 were also higher in blood serum and tissue samples from HBV-positive HCC patients than that in HBV-negative HCC patients. High levels of intracellular and extracellular S100A9 were also confirmed in HepG2 cells expressing 1.3-fold HBV genome or HBV-encoded X protein (HBx) as well as in a stable HBV-producing cell line HepG2.2.15. HBx was shown to facilitate translocation of NF-κB from the cytoplasm to the nucleus, and NF-κB bound to the promoter of S100A9 to enhance its transcription. Silencing S100A9 expression partially blocked HBx-induced growth and metastasis of HepG2 cells both in vitro and in vivo. Further, serum S100A9 levels were found to correlate with TNM stage, extrahepatic metastasis status and HBV DNA load in HBV-related HCC and also had a better diagnostic value for identifying extrahepatic metastasis. Our these data demonstrate that S100A9 plays a pivotal role in HBx-induced growth and metastasis of HCC and may serve as a potential diagnostic marker for extrahepatic metastasis.

Characterization of HBV integration patterns and timing in liver cancer and HBV-infected livers.

Integration of Hepatitis B virus (HBV) into the human genome can cause genetic instability, leading to selective advantages for HBV-induced liver cancer. Despite the large number of studies for HBV integration into liver cancer, little is known about the mechanism of initial HBV integration events owing to the limitations of materials and detection methods. We conducted an HBV sequence capture, followed by ultra-deep sequencing, to screen for HBV integrations in 111 liver samples from human-hepatocyte chimeric mice with HBV infection and human clinical samples containing 42 paired samples from non-tumorous and tumorous liver tissues. The HBV infection model using chimeric mice verified the efficiency of our HBV-capture analysis and demonstrated that HBV integration could occur 23 to 49 days after HBV infection via microhomology-mediated end joining and predominantly in mitochondrial DNA. Overall HBV integration sites in clinical samples were significantly enriched in regions annotated as exhibiting open chromatin, a high level of gene expression, and early replication timing in liver cells. These data indicate that HBV integration in liver tissue was biased according to chromatin accessibility, with additional selection pressures in the gene promoters of tumor samples. Moreover, an integrative analysis using paired non-tumorous and tumorous samples and HBV-related transcriptional change revealed the involvement of TERT and MLL4 in clonal selection. We also found frequent and non-tumorous liver-specific HBV integrations in FN1 and HBV-FN1 fusion transcript. Extensive survey of HBV integrations facilitates and improves the understanding of the timing and biology of HBV integration during infection and HBV-related hepatocarcinogenesis.

High expression of AKR1B10 predicts low risk of early tumor recurrence in patients with hepatitis B virus-related hepatocellular carcinoma

To clarify the relationship between aldo-keto reductase family 1 member B10 (AKR1B10) expression and early hepatocellular carcinoma (HCC) recurrence, this study detected AKR1B10 expression in tumor and adjacent non-tumor tissues from 110 patients with hepatitis B virus (HBV)-related HCC underwent liver resection and analyzed its correlations with clinicopathological characteristics and prognosis of these patients. Detected by quantitative reverse transcription polymerase chain reaction, AKR1B10 mRNA expression showed significantly higher in HCC tissues than in adjacent non-tumor tissues, with a low level in normal liver tissues. Similar results was confirmed at the protein level using immunohistochemistry and Western blotting. High AKR1B10 expression was negatively correlated with serum alpha-fetoprotein level and positively correlated with HBV-DNA level. Patients with high AKR1B10 expression had significantly higher disease-free survival than those with low expression within 2 years after liver resection. Multivariate analysis also confirmed high AKR1B10 expression to be a predictor of low risk of early HCC recurrence. In addition, high AKR1B10 expression was found to be a favorable factor of overall survival. These results suggest that AKR1B10 is involved in HBV-related hepatocarcinogenesis, but its high expression could predict low risk of early tumor recurrence in patients with HBV-related HCC after liver resection.

HBx promotes cell proliferation by disturbing the cross-talk between miR-181a and PTEN

Hepatitis B virus X protein (HBx) is involved in the initiation and progression of hepatocellular carcinoma (HCC). However, the mechanism is still needed to be elucidated. In this study, we explored the relationship between HBx and microRNA and their roles in hepato-carcinogenesis. Firstly, by global microarray-based microRNA profiling and qRT-PCR, we found miR-181a was strongly up-regulated in HepG2.2.15 cells (HBV positive) and pHBV1.3-expressing HepG2 cells, and HBx played a major role in it. Secondly, reduced PTEN protein expression in the presence of HBx was aslo mediated by miR-181a, and in the Luciferase reporter system, miR-181a inhibited the PTEN translation by binding the PTEN 3′-untranslated-region (UTR), and PTEN protein was decreased when epigenetic expression of miR-181a and rescued by knocking down miR-181a. Finally, HBx interrupted the balance between apoptosis and proliferation, which contributed to the development of hepatocellular carcinoma, was also related to the interaction of miR-181a and PTEN. Taken together, we presented here a novel cross-talk between miR-181a and PTEN which was raised by HBx, and this shined a new line in HBV-related hepato-carcinogenesis.

Aldo-keto reductase family 1 member B10 is associated with hepatitis B virus-related hepatocellular carcinoma risk.

Recent reports have indicated that aldo-keto reductase family 1 member B10 (AKR1B10), a cancer-related oxidoreductase, was upregulated in some chronic liver diseases. However, few studies have reported AKR1B10 expression in chronic hepatitis B virus (HBV)-infected patients. The aim of the present study was to analyze AKR1B10 expression and its relevance on hepatocellular carcinoma (HCC) development in patients with chronic HBV infection. Expression of AKR1B10 in the liver of 119 chronic HBV-infected patients was assessed and quantified immunohistochemically. A multivariate Cox model was used to estimate the hazard ratios of AKR1B10 expression for HCC development. The cumulative incidences of HCC were evaluated using Kaplan-Meier analysis. Expression of AKR1B10 in the study cohort ranged from 0% to 84%. During the median follow-up time (6.2years), 13 patients developed HCC. Multivariate analysis revealed that high AKR1B10 expression (≥15%) was an independent risk factor for HCC (hazard ratio, 10.8; 95% confidence interval, 3.0-38.6; P <0.001). The 5-year cumulative incidences of HCC were 20.6% and 2.6% in patients with high and low AKR1B10 expression, respectively (P <0.001). Patients with high AKR1B10 expression had significantly higher alanine aminotransferase levels during follow-up than those with low expression, even though antiviral treatment decreased HBV-DNA levels in both groups. Chronic HBV-infected patients with high hepatic AKR1B10 expression had an increased risk of HCC development. This suggests that AKR1B10 upregulation might play a role in the early stages of HBV-related hepatocarcinogenesis.

Hepatitis B virus X protein (HBx)-induced abnormalities of nucleic acid metabolism revealed by (1)H-NMR-based metabonomics.

Hepatitis B virus X protein (HBx) plays an important role in HBV-related hepatocarcinogenesis; however, mechanisms underlying HBx-mediated carcinogenesis remain unclear. In this study, an NMR-based metabolomics approach was applied to systematically investigate the effects of HBx on cell metabolism. EdU incorporation assay was conducted to examine the effects of HBx on DNA synthesis, an important feature of nucleic acid metabolism. The results revealed that HBx disrupted metabolism of glucose, lipids, and amino acids, especially nucleic acids. To understand the potential mechanism of HBx-induced abnormalities of nucleic acid metabolism, gene expression profiles of HepG2 cells expressing HBx were investigated. The results showed that 29 genes involved in DNA damage and DNA repair were differentially expressed in HBx-expressing HepG2 cells. HBx-induced DNA damage was further demonstrated by karyotyping, comet assay, Western blotting, immunofluorescence and immunohistochemistry analyses. Many studies have previously reported that DNA damage can induce abnormalities of nucleic acid metabolism. Thus, our results implied that HBx initially induces DNA damage, and then disrupts nucleic acid metabolism, which in turn blocks DNA repair and induces the occurrence of hepatocellular carcinoma (HCC). These findings further contribute to our understanding of the occurrence of HCC.

Autophagy and microRNA in hepatitis B virus-related hepatocellular carcinoma.

Approximately 350 million people worldwide are chronically infected by hepatitis B virus (HBV). HBV causes severe liver diseases including cirrhosis and hepatocellular carcinoma (HCC). In about 25% of affected patients, HBV infection proceeds to HCC. Therefore, the mechanisms by which HBV affects the host cell to promote viral replication and its pathogenesis have been the subject of intensive research efforts. Emerging evidence indicates that both autophagy and microRNAs (miRNAs) are involved in HBV replication and HBV-related hepatocarcinogenesis. In this review, we summarize how HBV induces autophagy, the role of autophagy in HBV infection, and HBV-related tumorigenesis. We further discuss the emerging roles of miRNAs in HBV infection and how HBV affects miRNAs biogenesis. The accumulating knowledge pertaining to autophagy and miRNAs in HBV replication and its pathogenesis may lead to the development of novel strategies against HBV infection and HBV-related HCC tumorigenesis.