Different signaling pathways in the livers of patients with chronic hepatitis B or chronic hepatitis C

The correlation of hepatocyte nuclear factor 4 alpha and 3 beta with hepatitis B virus replication in the liver of chronic hepatitis B patients

Hepatocyte nuclear factors 4 alpha (HNF4alpha) and 3 beta (HNF3beta) are members of a group of liver-enriched transcription factors (LETFs) that play important roles in regulating the replication of hepatitis B virus (HBV). Using cell culture and animal models, we showed that HNF4alpha supports HBV replication in nonhepatic cells and HNF3beta inhibits HBV replication. However, the expression of HNF4alpha and HNF3beta in the liver tissue of chronic HBV-infected patients and the relationship between the levels of HNF4alpha and HNF3beta and HBV replication are unclear. In this study, liver biopsy specimens from 86 chronic HBV-infected patients were collected. The expression levels of HNF4alpha, HNF3beta, hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) were detected by an immunohistochemical technique and the level of HBV DNA was checked by in situ hybridization with serial sections from liver biopsy tissue samples. We show here that samples with higher levels of HNF4alpha expression also have higher levels of HBsAg, HBcAg and HBV DNA. In contrast, in samples with higher levels of HNF3beta expression, levels of HBsAg, HBcAg and HBV DNA were lower. There was a positive correlation between HNF4alpha expression and HBV replication, and a negative correlation between HNF3beta expression and HBV replication, in the liver of chronic HBV-infected patients. This suggests that HNF4alpha and HNF3beta likely participate in HBV replication in patients with HBV infection, or that HBV replication may somehow influence the expression of HNF4alpha and HNF3beta in the liver.

Differential microRNA expression between hepatitis B and hepatitis C leading disease progression to hepatocellular carcinoma

MicroRNA (miRNA) plays an important role in the pathology of various diseases, including infection and cancer. Using real-time polymerase chain reaction, we measured the expression of 188 miRNAs in liver tissues obtained from 12 patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) and 14 patients with hepatitis C virus (HCV)-related HCC, including background liver tissues and normal liver tissues obtained from nine patients. Global gene expression in the same tissues was analyzed via complementary DNA microarray to examine whether the differentially expressed miRNAs could regulate their target genes. Detailed analysis of the differentially expressed miRNA revealed two types of miRNA, one associated with HBV and HCV infections (n = 19), the other with the stage of liver disease (n = 31). Pathway analysis of targeted genes using infection-associated miRNAs revealed that the pathways related to cell death, DNA damage, recombination, and signal transduction were activated in HBV-infected liver, and those related to immune response, antigen presentation, cell cycle, proteasome, and lipid metabolism were activated in HCV-infected liver. The differences in the expression of infection-associated miRNAs in the liver correlated significantly with those observed in Huh7.5 cells in which infectious HBV or HCV clones replicated. Out of the 31 miRNAs associated with disease state, 17 were down-regulated in HCC, which up-regulated cancer-associated pathways such as cell cycle, adhesion, proteolysis, transcription, and translation; 6 miRNAs were up-regulated in HCC, which down-regulated anti-tumor immune response.

CONCLUSION

miRNAs are important mediators of HBV and HCV infection as well as liver disease progression, and therefore could be potential therapeutic target molecules.

Intrahepatic gene expression profiles in chronic hepatitis B and autoimmune liver disease

BACKGROUND

DNA microarray technology has enabled genomewide analysis of gene transcript levels, yielding insight into the molecular nature of liver disease.

METHODS

We compared gene expression of liver biopsy specimens in 16 patients with different stages of chronic hepatitis B, five with autoimmune hepatitis (AIH), five with primary biliary cirrhosis (PBC), and six with druginduced hepatitis.

RESULTS

Of 21 073 genes, 424 showed different expression in a particular disease group on analysis of variance. Genes associated with extracellular matrix, cell growth, and DNA repair were noted in the advanced fibrotic stage of chronic hepatitis B (B-3), while gene expression regarding complement activation and the innate immune response decreased. When we compared gene expression at the relatively early stage in each disease group with pathway analysis, pathways relating to chemotaxis and cell homeostasis were selected in chronic hepatitis B. In PBC, gene expression relating to structural constituents and contractions of muscle such as actin and myosin were enhanced, in contrast to the downregulation of genes relating to protein binding in AIH. A hierarchical clustering analysis of hepatitis B genes defined five clusters. Generally, the transcripts upregulated according to disease progression were associated with signaling pathway/transcription, including tumor-associated calcium signal transducer 1 and chemokine ligand 19, and with cell communication, such as collagen. In two groups, all transcripts were downregulated; transcripts related to chemokine ligands and metallothionein were further depressed in B-3.

CONCLUSIONS

Analysis of gene expression in liver may be useful for understanding features of distinct liver diseases and for guiding disease progression, particularly in chronic hepatitis B.

Common transcriptional signature of tumor-infiltrating mononuclear inflammatory cells and peripheral blood mononuclear cells in hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is frequently associated with infiltrating mononuclear inflammatory cells. We performed laser capture microdissection of HCC-infiltrating and noncancerous liver-infiltrating mononuclear inflammatory cells in patients with chronic hepatitis C (CH-C) and examined gene expression profiles. HCC-infiltrating mononuclear inflammatory cells had an expression profile distinct from noncancerous liver-infiltrating mononuclear inflammatory cells; they differed with regard to genes involved in biological processes, such as antigen presentation, ubiquitin-proteasomal proteolysis, and responses to hypoxia and oxidative stress. Immunohistochemical analysis and gene expression databases suggested that the up-regulated genes involved macrophages and Th1 and Th2 CD4 cells. We next examined the gene expression profile of peripheral blood mononuclear cells (PBMC) obtained from CH-C patients with or without HCC. The expression profiles of PBMCs from patients with HCC differed significantly from those of patients without HCC (P < 0.0005). Many of the up-regulated genes in HCC-infiltrating mononuclear inflammatory cells were also differentially expressed by PBMCs of HCC patients. Analysis of the commonly up-regulated or down-regulated genes in HCC-infiltrating mononuclear inflammatory cells and PBMCs of HCC patients showed networks of nucleophosmin, SMAD3, and proliferating cell nuclear antigen that are involved with redox status, the cell cycle, and the proteasome system, along with immunologic genes, suggesting regulation of anticancer immunity. Thus, exploring the gene expression profile of PBMCs may be a surrogate approach for the assessment of local HCC-infiltrating mononuclear inflammatory cells.

Systematic -omics analysis of HBV-associated liver diseases

Hepatitis B virus (HBV) infection causes acute and chronic liver diseases and increases the risk of developing hepatocellular carcinoma (HCC). However, the pathogenesis of HBV infection and carcinogenesis of HBV-associated HCC are still elusive. In this review, systematic -omics studies made in the scales of genomics, transcriptomics and proteomics were discussed. The susceptibility to HBV infection and the course of disease progress are greatly different among individuals. Using population- or/and family-based approaches, relevant genes have been mapped or identified to be associated with host immune responses to HBV antigens and susceptibility to HCC. Comprehensive transcriptomic analyses have shown that the HBV-induced hepatocarcinogenesis may involve the whole course from signal transduction, transcription, translation to protein degradation, which differs in some measure from HCV-induced hepatocarcinogenesis, and that exogenous transcription factor HBX and endogenous NF-kappaB are likely two key points of the course. By the means of proteomics, dozens of important dysregulated proteins (including isoforms or fragments) were identified from carcinogenesis mechanism analysis and biomarker validation. Of them, the alteration of heat shock proteins and impairment of methylation cycle were found to be associated with clinical HBV-associated HCC. As a whole, the systematic -omics analysis of HBV-associated liver diseases has offered multi-scale pathological information in the process from HBV infection to HCC onset.

Hepatitis B virus X protein induces lipogenic transcription factor SREBP1 and fatty acid synthase through the activation of nuclear receptor LXRalpha

HBV (hepatitis B virus) is a primary cause of chronic liver disease, which frequently results in hepatitis, cirrhosis and ultimately HCC (hepatocellular carcinoma). Recently, we showed that HBx (HBV protein X) expression induces lipid accumulation in hepatic cells mediated by the induction of SREBP1 (sterol-regulatory-element-binding protein 1), a key regulator of lipogenic genes in the liver. However, the molecular mechanisms by which HBx increases SREBP1 expression and transactivation remain to be clearly elucidated. In the present study, we demonstrated that HBx interacts with LXRalpha (liver X receptor alpha) and enhances the binding of LXRalpha to LXRE (LXR-response element), thereby resulting in the up-regulation of SREBP1 and FAS (fatty acid synthase) in the presence or absence of the LXR agonist T0901317 in the hepatic cells and HBx-transgenic mice. Furthermore, HBx also augments the ability to recruit ASC2 (activating signal co-integrator 2), a transcriptional co-activator that controls liver lipid metabolic pathways, to the LXRE with LXRalpha. These studies place LXRalpha in a key position within the HBx-induced lipogenic pathways, and suggest a molecular mechanism through which HBV infection can stimulate the SREBP1-mediated control of hepatic lipid accumulation.

Expression of multidrug resistance-associated protein 3 and cytotoxic T cell responses in patients with hepatocellular carcinoma

BACKGROUND/AIMS

Multidrug resistance-associated protein 3 (MRP3) is a carrier-type transport protein belonging to the ABC transporters. It is expressed in normal tissues, and enhanced expression in many cancers has been reported. In this study, we investigated the usefulness of MRP3 as a target antigen in immunotherapy for hepatocellular carcinoma (HCC).

METHODS

The MRP3 expression level in HCC tissue was measured by quantitative PCR. MRP3-specific T cell responses were investigated by several immunological techniques using peripheral blood mononuclear cells or tumor-infiltrating lymphocytes.

RESULTS

The MRP3 expression level in HCC tissue was significantly higher than that in non-cancerous tissue (P<0.05). MRP3-specific cytotoxic T cells (CTLs) could be induced regardless of liver function, the presence or absence of HCV infection, the blood AFP level, and the stage of HCC. The CTLs showed cytotoxicity against HCC cells overexpressing MRP3. A negative correlation was present between the MRP3 expression level in HCC tissue and the frequency of MRP3-specific CTLs. The frequency of MRP3-specific CTLs increased after HCC treatment, such as transcatheter arterial embolization and radiofrequency ablation.

CONCLUSIONS

Our study demonstrates that MRP3 is a potential candidate for tumor antigen with strong immunogenicity in HCC immunotherapy.

Defining disease with laser precision: laser capture microdissection in gastroenterology

Laser capture microdissection (LCM) is an efficient and precise method for obtaining pure cell populations or specific cells of interest from a given tissue sample. LCM has been applied to animal and human gastroenterology research in analyzing the protein, DNA, and RNA from all organs of the gastrointestinal system. There are numerous potential applications for this technology in gastroenterology research, including malignancies of the esophagus, stomach, colon, biliary tract, and liver. This technology can also be used to study gastrointestinal infections, inflammatory bowel disease, pancreatitis, motility, malabsorption, and radiation enteropathy. LCM has multiple advantages when compared with conventional methods of microdissection, and this technology can be exploited to identify precursors to disease, diagnostic biomarkers, and therapeutic interventions.

Future of molecular profiling of human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a fatal disease occurring worldwide and developing mainly in chronic liver diseased patients. Despite routine screening of individuals at high risk, most of the patients are diagnosed at late stages of HCC. In addition, the recurrence rate after surgical resection of small tumors is high. Molecular profiling, including expression analysis, comparative genomics and proteomics, provides powerful tools to gain insight into the molecular mechanisms underlying carcinogenesis. Advances in bioinformatics have also allowed for the evaluation of large data sets. Therefore, molecular profiling of HCC using a Biological Expression Network Discovery (BLEND) strategy that integrates global molecular profiling data, including mRNA, miRNA, DNA methylation and DNA copy numbers from both the tumor and the surrounding microenvironment, along with mechanistic studies, may improve the diagnosis, treatment and prognosis of HCC patients. Such an approach will provide mechanistic insight into the pathogenesis of HCC, potentially leading to personalized medicine and the identification of new therapeutic targets.

Protein expression profile characteristic to hepatocellular carcinoma revealed by 2D-DIGE with supervised learning

Hepatocellular carcinoma (HCC) is one of the most common and aggressive human malignancies. Although several major risks related to HCC, e.g., hepatitis B and/or hepatitis C virus infection, aflatoxin B1 exposure, alcohol drinking and genetic defects have been revealed, the molecular mechanisms leading to the initiation and progression of HCC have not been clarified. To reduce the mortality and improve the effectiveness of therapy, it is important to detect the proteins which are associated with tumor progression and may be useful as potential therapeutic or diagnosis targets. However, previous studies have not yet revealed the associations among HCC cells, histological grade and AFP. Here, we performed two-dimensional difference gel electrophoresis (2D-DIGE) combined with MS for 18 HCC patients. To focus not on individual proteins but on multiple proteins associated with pathogenesis, we introduce the supervised feature selection based on stochastic gradient boosting (SGB) for identifying protein spots that discriminate HCC/non HCC, histological grade of moderate/well and high alpha-fetoprotein (AFP)/low AFP level without arbitrariness. We detected 18, 25 and 27 protein spots associated with HCC, histological grade and AFP level, respectively. We confirmed that SGB is able to identify the known HCC-related proteins, e.g., heat shock proteins, carbonic anhydrase 2. Moreover, we identified the differentially expressed proteins associated with histological grade of HCC and AFP level and found that aldo-keto reductase 1B10 (AKR1B10) is related to well differentiated HCC, keratin 8 (KRT8) is related to both histological grade and AFP level and protein disulfide isomerase-associated 3 (PDIA3) is associated with both HCC and AFP level. Our pilot study provides new insights on understanding the pathogenesis of HCC, histological grade and AFP level.

Comparative proteomic and transcriptomic profiling of the human hepatocellular carcinoma

Proteome analysis of human hepatocellular carcinoma (HCC) was done using two-dimensional difference gel electrophoresis. To gain an understanding of the molecular events accompanying HCC development, we compared the protein expression profiles of HCC and non-HCC tissue from 14 patients to the mRNA expression profiles of the same samples made from a cDNA microarray. A total of 125 proteins were identified, and the expression profiles of 93 proteins (149 spots) were compared to the mRNA expression profiles. The overall protein expression ratios correlated well with the mRNA ratios between HCC and non-HCC (Pearson's correlation coefficient: r=0.73). Particularly, the HCC/non-HCC expression ratios of proteins involved in metabolic processes showed significant correlation to those of mRNA (r=0.9). A considerable number of proteins were expressed as multiple spots. Among them, several proteins showed spot-to-spot differences in expression level and their expression ratios between HCC and non-HCC poorly correlated to mRNA ratios. Such multi-spotted proteins might arise as a consequence of post-translational modifications.

Hepatitis C virus: from oxygen free radicals to hepatocellular carcinoma

Epidemiological evidence clearly identifies chronic infection with hepatitis C virus (HCV) as a major risk factor for the development of hepatocellular carcinoma (HCC). Among the mechanisms that have been implicated in the pro-carcinogenic effect of HCV infection, an increased production of reactive oxygen species in the liver seems to have a major pathogenetic role in leading from chronic inflammation to cancer. Recent data have also demonstrated that HCV is capable of inducing this active production of free radicals per se, not just through inflammation, a feature peculiar to this virus and the specific activity of its core protein. This paper provides an overview of the inter-relationships between HCV, liver damage, free radical production and HCC, describing at least in part the complex network involving DNA oxidative damage, cytokine synthesis, proto-oncogene activation and oestrogen receptor expression, that may all be deeply involved in liver carcinogenesis.

Right hepatic lobectomy in elderly patients with hepatocellular carcinoma

BACKGROUND/AIMS

The outcome of hepatectomy in elderly patients with hepatocellular carcinoma have been reported, however neither the morphological nor functional hepatic regeneration in elderly patients have been fully investigated.

MATERIALS AND METHODS

Fifty-six patients with hepatocellular carcinoma, who underwent a right hepatic lobectomy over an 8-year period, were classified into three groups according to their age; group 1 (n = 7), more than 70 years of age; group 2 (n = 40), patients from 50 to 69 years of age and group 3 (n = 9), under 50 years of age. There were no significant differences regarding backgrounds or intra-operative parameters among the three groups. The perioperative hepatic function, postoperative complications and the regeneration rate of the remnant left lobe at 1 month after operation were compared.

RESULTS

No differences were found in the regeneration rate, however, the levels of the hepaplastin test and lecithin:cholesterol acyltransferase at 7 days after hepatectomy in group 1 (31.3%, 8.8 U) were significantly lower than those in groups 2 and 3 (37.4%, 18.4 U; 47.9%, 29.4 U, respectively). The incidence of hospital death due to hepatic failure in group 1 (42.9%) was also significantly higher than that of group 2 (5.0%) or group 3 (0%).

CONCLUSION

The decline of postoperative protein synthesis regardless of the voluminal regeneration is a characteristic of the elderly. This phenomenon might thus be an important promoter of postoperative hepatic failure which remains unpredictable using any type of examination. Therefore, at this time, a major hepatectomy is not recommended as a viable treatment alternative in the elderly.