Expression of HBx and COX-2 in chronic hepatitis B, cirrhosis and hepatocellular carcinoma: implication of HBx in upregulation of COX-2

Exploring the active ingredients and mechanisms of Liujunzi decoction in treating hepatitis B: a study based on network pharmacology, molecular docking, and molecular dynamics simulations

Liujunzi decoction (LJZD) is commonly used to treat hepatitis B virus (HBV), though its active ingredients and mechanisms are not fully known. This study identified core targets and active components of LJZD for treating hepatitis B (HB) through network pharmacology, molecular docking, and molecular dynamics simulation. Screening from databases yielded 533 active components, 2619 targets for LJZD, and 2910 for HB, with 891 intersecting targets. STRING and CytoHubba analyses identified AR and VDR as core targets, with key pathways including PI3K-Akt and MAPK. The findings clarify LJZD's multicomponent, multitarget mechanisms, supporting its clinical application for HB treatment.

Impact of Aspirin Use on Outcomes in Patients With Hepatocellular Cancer: A Nationwide Analysis

Background

Despite the use of new immunotherapies, hepatocellular carcinoma (HCC) has a poor survival rate. Through multiple molecular mechanisms, aspirin (ASA) has demonstrated a reduced incidence of HCC, however, the impact of long-term ASA use on in-hospital outcomes has not been studied.

Methods

We queried the National Inpatient Sample (NIS) database from 2016 to 2020 to identify patients with HCC. Patients were stratified into two groups, based on long-term ASA use. Information was collected regarding patient demographics, Elixhauser comorbidities, interventions, etiology, and decompensations of liver disease. Outcomes studied included sepsis, shock, acute kidney injury (AKI), intensive care unit (ICU) admission, and in-hospital mortality. The association between long-term ASA use and outcomes was studied using multivariate analysis.

Results

A total of 224,735 patients were included in the study. Of them, 18,835 (8.4%) patients were on long-term ASA. The majority of the patients with ASA use were White (61.3%), men (78.2%), and aged > 65 years old (68.8%). Patients in the ASA group had a higher incidence of non-alcoholic steatohepatitis (NASH) and decreased rates of hepatic decompensation than those not on ASA. Patients with ASA use had lower incidence of sepsis (2.76% vs. 3.54%), shock (4.86% vs. 8.23%), AKI (30.9% vs. 33.4%), ICU admission (3.88% vs. 7.4%) and in-hospital mortality (5.18% vs. 9.87%). After adjusting for confounding factors, ASA use was associated with a 30% lower risk of in-hospital mortality (adjusted odds ratio (aOR): 0.70, 95% confidence interval (CI): 0.60 - 0.82, P < 0.001). ASA users also had 21% lower odds of developing shock (aOR: 0.79, 95% CI: 0.67 - 0.94, P = 0.007) and 31% lower odds of requiring ICU admission (aOR: 0.69, 95% CI: 0.54 - 0.78, P < 0.001).

Conclusions

Our study noted that patients on long-term ASA use had better in-hospital outcomes such as mortality, shock, and ICU admissions compared to non-ASA users. These findings are of interest, and further randomized clinical trials confirming the benefits of ASA in improving outcomes in HCC patients need to be conducted.

Endoplasmic Reticulum Stress in Hepatitis B Virus and Hepatitis C Virus Infection

Endoplasmic reticulum (ER) stress, a type of cellular stress, always occurs when unfolded or misfolded proteins accumulating in the ER exceed the protein folding capacity. Because of the demand for rapid viral protein synthesis after viral infection, viral infections become a risk factor for ER stress. The hepatocyte is a cell with large and well-developed ER, and hepatitis virus infection is widespread in the population, indicating the interaction between hepatitis viruses and ER stress may have significance for managing liver diseases. In this paper, we review the process that is initiated by the hepatocyte through ER stress against HBV and HCV infection and explain how this information can be helpful in the treatment of HBV/HCV-related diseases.

Prostaglandin E2 and Receptors: Insight Into Tumorigenesis, Tumor Progression, and Treatment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common primary liver cancer with ∼750,000 annual incidence rates globally. PGE2, usually known as a pro-inflammatory cytokine, is over-expressed in various human malignancies including HCC. PGE2 binds to EP receptors in HCC cells to influence tumorigenesis or enhance tumor progression through multiple pathways such as EP1-PKC-MAPK, EP2-PKA-GSK3β, and EP4-PKA-CREB. In the progression of hepatocellular carcinoma, PGE2 can promote the proliferation and migration of liver cancer cells by affecting hepatocytes directly and the tumor microenvironment (TME) through ERK/COX-2/PGE2 signal pathway in hepatic stellate cells (HSC). For the treatment of hepatocellular carcinoma, there are drugs such as T7 peptide and EP1 antagonist ONO-8711 targeting Cox-2/PGE2 axis to inhibit tumor progression. In conclusion, PGE2 has been shown to be a traditional target with pleiotropic effects in tumorigenesis and progression of HCC that could be used to develop a new potential clinical impact. For the treatment study focusing on the COX-PGE2 axis, the exclusive usage of non-steroidal anti-inflammatory agents (NSAIDs) or COX-2-inhibitors may be replaced by a combination of selective EP antagonists and traditional anti-tumoral drugs to alleviate severe side effects and achieve better outcomes.

Inflammation and Cancer: From the Development of Personalized Indicators to Novel Therapeutic Strategies

Colorectal (CRC) and hepatocellular carcinoma (HCC) are associated with chronic inflammation, which plays a role in tumor development and malignant progression. An unmet medical need in these settings is the availability of sensitive and specific noninvasive biomarkers. Their use will allow surveillance of high-risk populations, early detection, and monitoring of disease progression. Moreover, the characterization of specific fingerprints of patients with nonalcoholic fatty liver disease (NAFLD) without or with nonalcoholic steatohepatitis (NASH) at the early stages of liver fibrosis is necessary. Some lines of evidence show the contribution of platelets to intestinal and liver inflammation. Thus, low-dose Aspirin, an antiplatelet agent, reduces CRC and liver cancer incidence and mortality. Aspirin also produces antifibrotic effects in NAFLD. Activated platelets can trigger chronic inflammation and tissue fibrosis via the release of soluble mediators, such as thromboxane (TX) A2 and tumor growth factor (TGF)-β, and vesicles containing genetic material (including microRNA). These platelet-derived products contribute to cyclooxygenase (COX)-2 expression and prostaglandin (PG)E2 biosynthesis by tumor microenvironment cells, such as immune and endothelial cells and fibroblasts, alongside cancer cells. Enhanced COX-2-dependent PGE2 plays a crucial role in chronic inflammation and promotes tumor progression, angiogenesis, and metastasis. Antiplatelet agents can indirectly prevent the induction of COX-2 in target cells by inhibiting platelet activation. Differently, selective COX-2 inhibitors (coxibs) block the activity of COX-2 expressed in the tumor microenvironment and cancer cells. However, coxib chemopreventive effects are hampered by the interference with cardiovascular homeostasis via the coincident inhibition of vascular COX-2-dependent prostacyclin biosynthesis, resulting in enhanced risk of atherothrombosis. A strategy to improve anti-inflammatory agents' use in cancer prevention could be to develop tissue-specific drug delivery systems. Platelet ability to interact with tumor cells and transfer their molecular cargo can be employed to design platelet-mediated drug delivery systems to enhance the efficacy and reduce toxicity associated with anti-inflammatory agents in these settings. Another peculiarity of platelets is their capability to uptake proteins and transcripts from the circulation. Thus, cancer patient platelets show specific proteomic and transcriptomic expression profiles that could be used as biomarkers for early cancer detection and disease monitoring.

Systematic Review and Meta-analysis: Association of Aspirin With Incidence of Hepatocellular Carcinoma

Aim: To explore the relationship between the use of aspirin and the incidence of hepatocellular carcinoma (HCC). Methods: MEDLINE, EMBASE, Web of Science and Cochrane CENTRAL databases were searched systematically from the earliest available date to 13 March 2020. The primary outcome was incidence of HCC, and the secondary outcomes were recurrence and mortality of HCC. The results were expressed as the Hazard Ratio (HR) and 95% confidence interval (CI). Based on the heterogeneity evaluated with the I 2 statistic, a meta-analysis was performed using either a random- or fixed-effects model. Results: A total of sixteen articles (2781100 participants) were included. There was lower incidence of HCC in aspirin users than those in non-aspirin users (HR, 0.56; 95% CI, 0.46-0.69; p < 0.001). Subgroup analysis further showed that the incidence of liver cancer in patients with alcoholic cirrhosis (HR, 0.14; 95% CI, 0.09-0.22; p < 0.001) and virus hepatitis (HR, 0.68; 95% CI, 0.62-0.74; p < 0.001) who use aspirin was lower than that of patients who do not use aspirin. In addition, aspirin was found to associate with decreased risk of HCC mortality (HR, 0.71; 95% CI, 0.65-0.78; p < 0.001), not HCC recurrence (HR, 0.52; 95% CI, 0.15-1.76; p = 0.291). Conclusions: Aspirin use is significantly associated with the low incidence rate of liver cancer.

Hepatitis B Viral Protein HBx and the Molecular Mechanisms Modulating the Hallmarks of Hepatocellular Carcinoma: A Comprehensive Review

With 296 million cases estimated worldwide, chronic hepatitis B virus (HBV) infection is the most common risk factor for hepatocellular carcinoma (HCC). HBV-encoded oncogene X protein (HBx), a key multifunctional regulatory protein, drives viral replication and interferes with several cellular signalling pathways that drive virus-associated hepatocarcinogenesis. This review article provides a comprehensive overview of the role of HBx in modulating the various hallmarks of HCC by supporting tumour initiation, progression, invasion and metastasis. Understanding HBx-mediated dimensions of complexity in driving liver malignancies could provide the key to unlocking novel and repurposed combinatorial therapies to combat HCC.

Farnesol alleviates diethyl nitrosamine induced inflammation and protects experimental rat hepatocellular carcinoma

Hepatocellular carcinoma is a well-known internal malignancy with increased worldwide mortality. The increased progression rate is closely associated with chronic liver diseases such as cirrhosis. Chemical carcinogens cause tumor advocacy over free radical metabolites to causes numerous biochemical and molecular changes that bring oxidative stress. In addition, inflammatory cells and its growth factor promotes the progression of liver cancer through deregulates the numerous cellular signaling pathways involved in normal cellular proliferation. Plant derived phytochemicals have a better complimentary potency to defend against a wide array of free radical mediated diseases such as cancer. More recently, we have evaluated the anticancer effect of Farnesol against DEN induced hepatocellular carcinoma in male wistar albino rats. However, the possible mechanism in which Farnesol attributes its anticancer effect against DEN induced liver cancer remains unknown. Hence in the present study, an attempt has been made to reduce the oxidative stress by appraise the antioxidant effect by Farnesol in DEN induced hepatocellular carcinoma. Elevated oxidative stress markers with concomitant decreased cellular antioxidants levels were observed in DEN induced hepatic tissues. Further, proliferating nuclei with increased proliferating cell nucleolar antigen (PCNA) and inflammatory mediator expression were observed in DEN induced rats. Oral supplementation of Farnesol to DEN induced rats significantly decrease the oxidative stress markers and increase the cellular antioxidant status. Moreover, Farnesol treatment decreases the argyrophilic nuclear organizer region and PCNA along with decreased expression of inflammatory mediators suggest that Farnesol treatment restores DEN induced hepatic abnormalities and protects liver from cancer progression.

Hepatic COX-2 expression protects mice from an alcohol-high fat diet-induced metabolic disorder by involving protein acetylation related energy metabolism

PURPOSE

A diet high in fat and ethanol often results in chronic metabolic disorder, hepatic steatosis, and liver inflammation. Constitutive hepatic cyclooxygenase-2 (COX-2) expression could protect from high fat-induced metabolism disturbance in a murine model. In this study, we explored the influence of hCOX-2 transgenic [TG] to high fat with ethanol-induced metabolic disorder and liver injury using a mouse animal model.

METHODS

12-week-old male hepatic hCOX-2 transgenic (TG) or wild type mice (WT) were fed either a high fat and ethanol liquid diet (HF+Eth) or a regular control diet (RCD) for 5 weeks (four groups: RCD/WT, RCD/TG; HF+Eth/TG, HF+Eth/WT). We assessed metabolic biomarkers, cytokine profiles, histomorphology, and gene expression to study the impact of persistent hepatic COX-2 expression on diet-induced liver injury.

RESULTS

In the HF+Eth diet, constitutively hepatic human COX-2 expression protects mice from body weight gain and white adipose tissue accumulation, accompanied by improved IPGTT response, serum triglyceride/cholesterol levels, and lower levels of serum and liver inflammatory cytokines. Histologically, hCOX-2 mice showed decreased hepatic lipid droplets accumulation, decreased hepatocyte ballooning, and improved steatosis scores. Hepatic hCOX-2 overexpression enhanced AKT insulin signaling and increased fatty acid synthesis in both RCD and HF+Eth diet groups. The anti-lipogenic effect of hCOX-2 TG in the HF+Eth diet animals was mediated by increasing lipid disposal through enhanced β-oxidation via elevations in the expression of PPARα and PPARγ, and increased hepatic autophagy as assessed by the ratio of autophagy markers LC3 II/I in hepatic tissue. Various protein acetylation pathway components, including HAT, HDAC1, SIRT1, and SNAIL1, were modulated in hCOX-2 TG mice in either RCD or HF+Eth diet.

CONCLUSIONS

Hepatic human COX-2 expression protected mice from the metabolic disorder and liver injury induced by a high fat and ethanol diet by enhancing hepatic lipid expenditure. Epigenetic reprogramming of diverse metabolic genes might be involved in the anti-lipogenic effect of COX-2.

Aspirin in Hepatocellular Carcinoma

Preclinical and clinical studies provide evidence for aspirin as a preventative agent for cancer. Compelling direct evidence supports a chemopreventive effect of aspirin in individuals at high risk of developing colorectal cancer due to Lynch syndrome, while indirect evidence indicates that aspirin may reduce the risk of and mortality from sporadic colorectal cancer. There is weaker evidence for a protective effect of aspirin against all cancers taken as a group. Nevertheless, the results of recent retrospective cohort studies consistently indicate a beneficial effect of aspirin as a chemopreventive or adjuvant chemotherapeutic agent in hepatocellular carcinoma (HCC). Epidemiologic studies conducted in the general population or in selected populations at higher risk for HCC reveal that regular aspirin use is associated with reduced HCC incidence. In addition, aspirin may act as an adjuvant to other therapies in reducing HCC recurrence. According to studies in animal models, the cancer-preventative effect of aspirin may be related to its antiplatelet and anti-inflammatory activities. Prospective studies are warranted to determine whether aspirin should be recommended to diverse populations of patients at risk for HCC.

Molecular basis of the interaction of the human tyrosine phosphatase PTPN3 with the hepatitis B virus core protein

Interactions between the hepatitis B virus core protein (HBc) and host cell proteins are poorly understood, although they may be essential for the propagation of the virus and its pathogenicity. HBc has a C-terminal PDZ (PSD-95, Dlg1, ZO-1)-binding motif (PBM) that is responsible for interactions with host PDZ domain-containing proteins. In this work, we focused on the human protein tyrosine phosphatase non-receptor type 3 (PTPN3) and its interaction with HBc. We solved the crystal structure of the PDZ domain of PTPN3 in complex with the PBM of HBc, revealing a network of interactions specific to class I PDZ domains despite the presence of a C-terminal cysteine in this atypical PBM. We further showed that PTPN3 binds the HBc protein within capsids or as a homodimer. We demonstrate that overexpression of PTPN3 significantly affects HBV infection in HepG2 NTCP cells. Finally, we performed proteomics studies on both sides by pull-down assays and screening of a human PDZ domain library. We identified a pool of human PBM-containing proteins that might interact with PTPN3 in cells and that could be in competition with the HBc PBM during infection, and we also identified potential cellular partners of HBc through PDZ-PBM interactions. This study opens up many avenues of future investigations into the pathophysiology of HBV.

Aspirin decreases hepatocellular carcinoma risk in hepatitis C virus carriers: a nationwide cohort study

Background

Aspirin has been found to lower the occurrence rates of some cancers through the inhibition of the cyclooxygenase enzyme. For example, there is a well-known association between aspirin use and the occurrence of hepatocellular carcinoma (HCC) in hepatitis B virus (HBV) carriers. However, the association, if any, between aspirin use and HCC in hepatitis C virus (HCV) carriers is unknown. Therefore, this study compared the occurrence rates of HCC in HCV carriers treated with or without aspirin.

Methods

The participants in this retrospective cohort study consisted of people newly diagnosed with HCV in Taiwan from 2000 to 2012. Those who were treated with aspirin were defined as the control group, whereas those not treated with aspirin were defined as the comparison cohort. We used a 1:1 propensity score matching by age, sex, comorbidities, drugs, diagnosis year, and index year with covariate assessment.

Results

Our study sample consisted of 2980 aspirin-treated HCV carriers and 7771 non-aspirin-treated HCV carriers. After propensity score matching, each cohort consisted of 1911 HCV carriers. The adjusted hazard ratio (aHR) of HCC incidence in the aspirin users (aHR = 0.56, 95% CI = 0.43–0.72, p < 0.001) was significantly lower than that in the non-aspirin users. A Kaplan-Meier analysis showed that among the HCV carriers, the aspirin users had a lower cumulative incidence rate of HCC over the first 10 years of aspirin treatment (p < 0.0001).

Conclusions

The HCC incidence rate was lower in the aspirin-using HCV carriers than in the non- aspirin-using HCV carriers, indicating that the effects of aspirin might occur through inhibition of the cyclooxygenase enzyme pathway. Moreover, protection from HCC was provided by less than a year of aspirin treatment, while treatment with aspirin for 1 to 2 years exhibited the greatest protective effect. We therefore encourage aspirin treatment to prevent HCC in HCV carriers.

Altered expression of COX-2 and TNF-α in patients with hepatocellular carcinoma

BACKGROUND AND AIM

hepatocellular carcinoma is a type of cancer related with inflammation, as 90% of cases develop in a chronic inflammation condition. Excess inflammation can affect tissue homeostasis. Cytokines and inflammatory mediators are immunological components that can influence the functioning of cells and tissues. In addition, the estrogen receptor appears to play an important role in hepatocarcinogenesis. The aim of the study was to evaluate the expression of inflammatory markers and ER in patients with hepatocellular carcinoma.

METHODS

data from 143 patients of ISCMPA were analyzed. Immunohistochemistry was performed of cyclooxygenase-2 enzyme (COX-2), nuclear factor kappa B (NF-κB), tumor necrosis factor alpha (TNF-α) and ER in paraffin-embedded hepatic tissue. The percentage of the stained area, intensity of staining and of the number of ER positive nuclei were evaluated using the ImageJ 1.50 software.

RESULTS AND CONCLUSION

there was a significant difference between the groups in terms of the percentage of marked area (p = 0.040) for COX-2 and the intensity of staining of TNF-α (p = 0.030). No significant differences were observed in any of other parameters evaluated. In conclusion, COX-2 and TNF-α are possible markers that should be further studied to determine their immunohistochemical profile and role in HCC development.

Hepatitis C virus core protein modulates several signaling pathways involved in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer, and hepatitis C virus (HCV) infection plays a major role in HCC development. The molecular mechanisms by which HCV infection leads to HCC are varied. HCV core protein is an important risk factor in HCV-associated liver pathogenesis and can modulate several signaling pathways involved in cell cycle regulation, cell growth promotion, cell proliferation, apoptosis, oxidative stress and lipid metabolism. The dysregulation of signaling pathways such as transforming growth factor β (TGF-β), vascular endothelial growth factor (VEGF), Wnt/β-catenin (WNT), cyclooxygenase-2 (COX-2) and peroxisome proliferator-activated receptor α (PPARα) by HCV core protein is implicated in the development of HCC. Therefore, it has been suggested that this protein be considered a favorable target for further studies in the development of HCC. In addition, considering the axial role of these signaling pathways in HCC, they are considered druggable targets for cancer therapy. Therefore, using strategies to limit the dysregulation effects of core protein on these signaling pathways seems necessary to prevent HCV-related HCC.

14-3-3ζ binds to hepatitis B virus protein X and maintains its protein stability in hepatocellular carcinoma cells

14‐3‐3ζ, a phosphopeptide‐binding molecule, is reportedly overexpressed in the cancerous tissues of patients with hepatocellular carcinoma (HCC). Hepatitis B virus (HBV) protein X (HBx) draws intensive attention in HBV‐related HCC because it not only regulates HBV replication, but also promotes carcinogenesis by interacting with various tumor or antitumor molecules. This study is performed to investigate whether and how 14‐3‐3ζ interacts with HBx. The coimmunoprecipitation (Co‐IP) results showed that 14‐3‐3ζ bond to HBx in HBV‐infected Hep3B HCC cells and CSQT‐2 portal vein tumor thrombosis (PVTT) cells. By performing Co‐IP assay in HBV‐free Huh7 cells expressing wild‐type HBx, mutant HBx‐S31A, or HBx‐S31D (serine³¹ was mutated into alanine³¹ or aspartic acid³¹), we found that the phosphorylated serine³¹ with its near amino acid residues constituted a RPLphosphoS³¹GP (R, arginine; P, proline; L, leucine; S, serine; G, glycine) motif in HBx for 14‐3‐3ζ docking. This 14‐3‐3ζ‐HBx interaction was partly impaired when Akt signaling transduction was blocked by LY294002. Furthermore, 14‐3‐3ζ silencing augmented HBx ubiquitination and decreased its expression in cancer cells and xenograft tumor. The migratory and invasive abilities of CSQT‐2 cells were inhibited upon 14‐3‐3ζ silencing, whereas partly restored by HBx overexpression. Additionally, 14‐3‐3ζ positively correlated with HBx to be overexpressed in the primary HCC tissues (r = 0.344) and metastatic PVTT (r = 0.348). In summary, findings of this study reveal a novel 14‐3‐3ζ‐HBx interaction in HCC cells and suggest 14‐3‐3ζ as a candidate target for treating HBV‐related HCC.

Effects of celecoxib on cell apoptosis and Fas, FasL and Bcl-2 expression in a BGC-823 human gastric cancer cell line

Fas, which is an apoptotic-related protein, has an important role in cell apoptosis. Fas ligand (FasL) binds to Fas and activates apoptosis signal transduction. We previously demonstrated that the efficiency of celecoxib inhibited the proliferation and apoptosis of HT-29 colon cancer cell line. The BGC823 cell line was used as an experimental model to evaluate the potential role of celecoxib on gastric cancer cell apoptosis. Inhibitory effects of celecoxib on cell viability were determined by MTT assay. Cell apoptosis was evaluated by flow cytometric analysis and laser confocal microscopy. The results of the present study demonstrated that celecoxib inhibited the viability of BGC823 cells in a concentration- and time-dependent manner. Furthermore, the effect of BGC823 cells apoptosis was increased in a concentration-dependent manner. Western blotting was used to determine the protein expression levels of Fas, FasL, and B-cell lymphoma-2 (Bcl-2). During the celecoxib-induced apoptosis of BGC823 cells, celecoxib upregulated Fas expression and downregulated FasL and Bcl-2 expression in a concentration-dependent manner. These results suggest that celecoxib inhibited the growth and induced apoptosis of BGC823 gastric cancer cells by regulating the protein expression of Fas, FasL and Bcl-2.

Umbelliferon-α-d-glucopyranosyl-(2I→1II)-α-Dglucopyranoside ameliorates Diethylnitrosamine induced precancerous lesion development in liver via regulation of inflammation, hyperproliferation and antioxidant at pre-clinical stage

It is well documented that anomalous production of inflammatory proteins linked with most of the toxic expression and genesis of diverse chronic disease including cancer. Diethylnitrosamine (DEN) a well-known hepatotoxin and hepatocarcinogen, can induce oxidative stress and inflammatory reaction in it. Umbelliferone, secondary metabolites, is present in different plants and widely consumed by humans as medicine and food supplements. The aim of the current study was to scrutinize the chemoprotective potential of umbelliferon-α-d-glucopyranosyl-(2^I→1^II)-α-d-glucopyranoside (UFD) against DEN-induced hepatocellular carcinoma (HCC) in experimental rats. Single intraperitoneal injection of DEN (200mg/kg) was used for induction of HCC in rats and rats were grouped and orally treated with UFD (5, 10 and 20mg/kg) dose for 22 weeks. Parameters under investigation included hepatic, non-hepatic enzymes, oxidative stress, pro-inflammatory cytokines, COX-2 and NF-κB level along with histopathological examination in HCC rats. UFD exerted protective effect via reduction of oxidative stress, liver and non-liver parameters in a dose-dependent manner. It also reduced the expression of TNF-α, IL-1β, IL-6 and COX-2 in diseased rats. Our result revealed the essential repression of the inflammation cascade through modulation of nuclear factor-kappa B (NF-κB) signaling pathway.

Increased CD86 but Not CD80 and PD-L1 Expression on Liver CD68+ Cells during Chronic HBV Infection

BACKGROUND

The failure to establish potent anti-HBV T cell responses suggests the absence of an effective innate immune activation. Kupffer cells and liver-infiltrating monocytes/macrophages have an essential role in establishing anti-HBV responses. These cells express the costimulatory molecules CD80 and CD86. CD80 expression on antigen-presenting cells (APCs) induces Th1 cell differentiation, whereas CD86 expression drives the differentiation towards a Th2 profile. The relative expression of CD80, CD86 and PD-L1 on APCs, regulates T cell activation. Few studies investigated CD80 and CD86 expression on KCs and infiltrating monocytes/macrophages in HBV-infected liver and knowledge about the expression of PD-L1 on these cells is controversial. The expression of these molecules together in CD68+ cells has not been explored in HBV-infected livers.

METHODS

Double staining immunohistochemistry was applied to liver biopsies of HBV-infected and control donors to explore CD80, CD86 and PD-L1 expression in the lobular and portal areas.

RESULTS

Chronic HBV infection was associated with increased CD68+CD86+ cell count and percentage in the lobular areas, and no changes in the count and percentage of CD68+CD80+ and CD68+PD-L1+ cells, compared to the control group. While CD68+CD80+ cell count in portal areas correlated with the fibrosis score, CD68+CD80+ cell percentage in lobular areas correlated with the inflammation grade.

CONCLUSION

The upregulation of CD86 but not CD80 and PD-L1 on CD68+ cells in HBV-infected livers, suggests that these cells do not support the induction of potent Th1. Moreover, the expression of CD80 on CD68+ cells correlates with liver inflammation and fibrosis.

Preventive effects of the polysaccharide of Larimichthys crocea swim bladder on carbon tetrachloride (CCl4)-induced hepatic damage

The aim of the present study was to determine the preventive effects of the polysaccharide of Larimichthys crocea swim bladder (PLCSB) on CCl4-induced hepatic damage in ICR mice. The in vitro preventive effects of PLCSB on CCl4-induced liver cytotoxic effect were evaluated in BRL 3A rat liver cells using the MTT assay. The serum levels of AST, ALT, and LDH in mice were determined using commercially available kits. The levels of IL-6, IL-12, TNF-α, and IFN-γ were determined using ELISA kits. The pathological analysis of hepatic tissues was performed with H and E staining, and the gene and protein expressions were determined by RT-PCR and Western blotting, respectively. PLCSB (20 μg·mL(-1)) could increase the growth of BRL 3A rat liver cells treated with CCl4. The serum levels of AST, ALT, and LDH were significantly decreased when the mice were treated with two doses of PLCSB, compared with the control mice (P < 0.05). PLCSB-treated groups also showed reduced levels of the serum pro-inflammatory cytokines IL-6, IL-12, TNF-α, and IFN-γ. PLCSB could decrease the liver weight, compared to the CCl4-treated control mice. The histopathology sections of liver tissues in the 100 mg·kg(-1) PLCSB group indicated that the animals were recovered well from CCl4 damage, but the 50 mg·kg(-1) PLCSB group showed necrosis to a more serious extent. The 100 mg·kg(-1) PLCSB group showed significantly decreased mRNA and protein expression levels of NF-κB, iNOS, and COX-2, and increased expression of IκB-α compared with the CCl4-treated control group. In conclusion, PLCSB prevented from CCl4-induced hepatic damage in vivo.

Autophagy Mediates HBx-Induced Nuclear Factor-κB Activation and Release of IL-6, IL-8, and CXCL2 in Hepatocytes

Hepatitis B virus (HBV) and one of its encoded proteins, HBV X protein (HBx), have been shown to induce autophagy in hepatoma cells. Substantial evidence indicates that autophagy is a potent suppressor of inflammation. However, sporadic reports suggest that autophagy could promote pro-inflammatory cytokine expression and inflammation in some biological contexts. Here, we show that overexpression of HBx induces LC3B-positive autophagosome formation, increases autophagic flux and enhances the expression of ATG5, ATG7, and LC3B-II in normal hepatocytes. Abrogation of autophagy by small interfering RNA against ATG5 and ATG7 prevents HBx-induced formation of autophagosomes. Autophagy inhibition also abrogates HBx-induced activation of nuclear factor-κB (NF-κB) and production of interleukin-6 (IL-6), IL-8, and CXCL2. These findings suggest that autophagy is required for HBx-induced NF-κB activation and pro-inflammatory cytokine production and could shed new light on the complex role of autophagy in the modulation of inflammation.

Characterization of hepatic lipid profiles in a mouse model with nonalcoholic steatohepatitis and subsequent fibrosis

Nonalcoholic steatohepatitis (NASH) is a major health problem since it often leads to hepatocellular carcinoma. However, the underlying mechanisms of NASH development and subsequent fibrosis have yet to be clarified. We compared comprehensive lipidomic profiles between mice with high fat diet (HFD)-induced steatosis and STAM mice with NASH and subsequent fibrosis. The STAM mouse is a model that demonstrates NASH progression resembling the disease in humans: STAM mice manifest NASH at 8 weeks, which progresses to fibrosis at 12 weeks, and finally develop hepatocellular carcinoma. Overall, 250 lipid molecules were detected in the liver using liquid chromatography-mass spectrometry. We found that STAM mice with NASH presented a significantly higher abundance of sphingolipids and lower levels of triacylglycerols than the HFD-fed control mice. The abundance of certain fatty acids in phospholipid side chains was also significantly different between STAM and control mice, although global levels of phosphatidylcholines and phosphatidylethanolamines were comparable. Finally, increase in levels of acylcarnitines and some diacylglycerols was observed in STAM mice toward the fibrosis stage, but not in age-matched control mice. Our study provides insights into the lipid status of the steatotic, NASH, and fibrotic liver that would help elucidate the molecular pathophysiology of NASH progression.

Truncated HBx-dependent silencing of GAS2 promotes hepatocarcinogenesis through deregulation of cell cycle, senescence and p53-mediated apoptosis

Hepatocellular carcinoma (HCC) is a worldwide threat to public health, especially in China, where chronic hepatitis B virus (HBV) infection is found in 80-90% of all HCCs. The HBV-encoded X antigen (HBx) is a trans-regulatory protein involved in virus-induced hepatocarcinogenesis. Although the carboxyl-terminus-truncated HBx, rather than the full-length counterpart, is frequently overexpressed in human HCCs, its functional mechanisms are not fully defined. We investigated the molecular function of a naturally occurring HBx variant which has 35 amino acids deleted at the C-terminus (HBxΔ35). Genome-wide scanning analysis and PCR validation identified growth arrest-specific 2 (GAS2) as a direct target of HBxΔ35 at transcriptional level in human immortalized liver cells. HBxΔ35 was found to bind the promoter region of GAS2 and attenuate its expression to promote hepatocellular proliferation and tumourigenicity. Further functional assays demonstrated that GAS2 induces p53-dependent apoptosis and senescence to counteract HBxΔ35-mediated tumourigenesis. Notably, GAS2 expression was significantly down-regulated in HCCs compared with the corresponding normal tissues. In conclusion, our integrated study uncovered a novel viral mechanism in hepatocarcinogenesis, wherein HBxΔ35 deregulates cell growth via direct silencing of GAS2 and thereby provides a survival advantage for pre-neoplastic hepatocytes to facilitate cancer development.

Possible role of tocopherols in the modulation of host microRNA with potential antiviral activity in patients with hepatitis B virus-related persistent infection: a systematic review

Hepatitis B virus (HBV) infection represents a serious global health problem and persistent HBV infection is associated with an increased risk of cirrhosis, hepatocellular carcinoma and liver failure. Recently, the study of the role of microRNA (miRNA) in the pathogenesis of HBV has gained considerable interest as well as new treatments against this pathogen have been approved. A few studies have investigated the antiviral activity of vitamin E (VE) in chronic HBV carriers. Herein, we review the possible role of tocopherols in the modulation of host miRNA with potential anti-HBV activity. A systematic research of the scientific literature was performed by searching the MEDLINE, Cochrane Library and EMBASE databases. The keywords used were 'HBV therapy', 'HBV treatment', 'VE antiviral effects', 'tocopherol antiviral activity', 'miRNA antiviral activity' and 'VE microRNA'. Reports describing the role of miRNA in the regulation of HBV life cycle, in vitro and in vivo available studies reporting the effects of VE on miRNA expression profiles and epigenetic networks, and clinical trials reporting the use of VE in patients with HBV-related chronic hepatitis were identified and examined. Based on the clinical results obtained in VE-treated chronic HBV carriers, we provide a reliable hypothesis for the possible role of this vitamin in the modulation of host miRNA profiles perturbed by this viral pathogen and in the regulation of some cellular miRNA with a suggested potential anti-HBV activity. This approach may contribute to the improvement of our understanding of pathogenetic mechanisms involved in HBV infection and increase the possibility of its management and treatment.

Distinctive pharmacological differences between liver cancer cell lines HepG2 and Hep3B

As cellular models for in vitro liver cancer and toxicity studies, HepG2 and Hep3B are the two most frequently used liver cancer cell lines. Because of their similarities they are often treated as the same in experimental studies. However, there are many differences that have been largely over-sighted or ignored between them. In this review, we summarize the differences between HepG2 and Hep3B cell lines that can be found in the literature based on PubMed search. We particularly focus on the differential gene expression, differential drug responses (chemosensitivity, cell cycle and growth inhibition, and gene induction), signaling pathways associated with these differences, as well as the factors in governing these differences between HepG2 and Hep3B cell lines. Based on our analyses of the available data, we suggest that neither HBx nor p53 may be the crucial factor to determine the differences between HepG2 and Hep3B cell lines although HBx regulates the expression of the majority of genes that are differentially expressed between HepG2 and Hep3B. Instead, the different maturation stages in cancer development of the original specimen between HepG2 and Hep3B may be responsible for the differences between them. This review provides insight into the molecular mechanisms underlying the differences between HepG2 and Hep3B and help investigators especially the beginners in the areas of liver cancer research and drug metabolism to fully understand, and thus better use and interpret the data from these two cell lines in their studies.

The co-localization of HBx and COXIII upregulates COX-2 promoting HepG2 cell growth

HBx is a multifunctional regulator that interacts with host factors to contribute to the development of hepatocellular carcinoma. In this study, to explore the co-localization of HBx and COXIII in HepG2 cells and to investigate the molecular mechanism of HBx in HepG2 cell growth promotion, we first constructed a HepG2 cell line stably expressing the HBx gene in vitro by lentivirus vectors. In addition, we found that HBx co-localized with the inner mitochondrial protein, COXIII, in HepG2 cells by confocal laser scanning microscopy. It led to changes of mitochondrial biogenesis and morphology, including upregulation of COXIII protein expression, increased cytochrome c oxidase activity and higher mitochondrial membrane potential. The upregulation of COX-2 caused by HBx through generation of mitochondrial reactive oxygen species promoted cell growth. Thus, we conclude that co-localization of HBx and COXIII leads to upregulation of COX-2 that promotes HepG2 cell growth. Such a mechanism provides deeper insights into the molecular mechanism of HBV-associated hepatocellular carcinoma.

Dissecting the pleiotropic actions of HBx mutants against hypoxia in hepatocellular carcinoma

Error-prone integration of the hepatitis B virus X protein (HBx) into the hepatocellular genome generates a multitude of mutants exerting diverse effects on the development and progression of hepatocellular carcinoma (HCC). A recent study by Lai and colleagues revealed the disparate regulatory activity of clinically-predominant HBx mutants towards hypoxia-inducible factor-1α (HIF-1α), a central regulator of tumor angiogenesis, proliferation, metastasis and differentiation. These findings have shed insight into specific viral contribution of hypoxic response during hepatocarcinogenesis.

15-Deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) promotes apoptosis of HBx-positive liver cells

This study aims to investigate the inflammatory response characteristics of liver cells caused by HBV x protein (HBx) and the unique function of the PGE2 inhibitor on HBx-positive liver cells. Tetrazolium blue colorimetric method, flow cytometry, and Western blot were performed to detect the proliferation, cycle, and apoptosis protein expression of HBx-positive HL7702 liver and control cells. The effect of the PGE2 inhibitor 15-Deoxy-Δ(12,14)-prostaglandin J2 (15d-PGJ2) on the growth of HL7702-HBx was also observed. HBx induces the PGE2 accumulation in HL7702 liver cells and promotes their growth and inhibits their apoptosis. HL7702-HBx and HL7702 cells showed increased apoptosis rate, increased apoptosis-promoting protein expression, and reduced apoptosis-inhibiting protein expression under the effect of 15d-PGJ2, and the changes in HL7702-HBx cells were more significant than in HL7702 cells. HBx expression causes liver cells to be more sensitive to the apoptosis-promoting function of 15d-PGJ2. Therefore, the use of 15d-PGJ2 may be a new method for the prevention or treatment of inflammatory changes to cancer caused by HBV infection in liver cells.

HBx protein promotes oval cell proliferation by up-regulation of cyclin D1 via activation of the MEK/ERK and PI3K/Akt pathways

Growing evidence has shown that hepatic oval cells, also named liver progenitor cells, play an important role in the process of liver regeneration in various liver diseases. Oval cell proliferation has been reported in hepatitis B virus (HBV)-associated hepatocellular carcinoma (HCC) and chronic liver disease. Studies have found expression of HBV surface and core antigens in oval cells in the livers of patients with HCC, suggesting that HBV infection of oval cells could be a mechanism of human hepatocarcinogenesis. In addition, there is evidence of multiplication of HBV in oval cell culture. However, little research has been performed to explore the role of HBV-encoded proteins in the proliferation of hepatic oval cells. Previously, we successfully transfected the HBV x (HBx) gene, one of the four genes in the HBV genome, into a rat LE/6 oval cell line. In this study, we tested whether or not the transfected HBx gene could affect oval cell proliferation in vitro. Our results show that overexpression of HBx promotes the proliferation of oval cells and increases cyclin D1 expression, assessed at both the mRNA and protein levels. We also found that HBx activated the PI-3K/Akt and MEK/ERK1/2 pathways in HBx-transfected oval cells. Furthermore, the HBx-induced increases in cyclin D1 expression and oval cell proliferation were completely abolished by treatment with either MEK inhibitor PD184352 or PI-3K inhibitor LY294002. These results demonstrated that HBx has the ability to promote oval cell proliferation in vitro, and its stimulatory effects on cell proliferation and expression of cyclin D1 depend on the activation of the MEK/ERK and PI3K/Akt signaling pathways in cultured oval cells.

Different roles of inducible nitric oxide synthase and cyclooxygenase-2 in carcinogenesis and metastasis of intrahepatic cholangiocarcinoma

Inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been implicated in chronic inflammatory conditions and carcinogenesis. However, little is known about the biological significance of iNOS and COX-2 in cholangiocarcinoma or its precursors or metastatic lesions. We examined iNOS and COX-2 immunohisotochemical expression in 40 biliary intraepithelial neoplasias, 134 primary intrahepatic cholangiocarcinoma cases, and 27 metastatic lymph nodes and analyzed the correlations with grade of atypia of biliary intraepithelial neoplasia, clinicopathological factors and outcomes of intrahepatic cholangiocarcinoma. iNOS and COX-2 expression was highly expressed in reactive epithelium and biliary intraepithelial neoplasia. In intrahepatic cholangiocarcinoma, lymphatic invasion and lymph node metastasis were significantly correlated with negative iNOS expression (P = .0002, P = .0324, respectively) and positive COX-2 expression (P = .0012, P = .0063, respectively). Vascular endothelial growth factor-C expression was associated with COX-2 expression (P = .0053), but not with iNOS expression. COX-2 expression in primary intrahepatic cholangiocarcinoma was higher than that in metastatic lymph nodes (P < .0001). COX-2-positive expression indicated a poor intrahepatic cholangiocarcinoma outcome (P = .0273). This study indicates that iNOS and COX-2 may play roles in carcinogenesis via biliary intraepithelial neoplasia, but play different roles in metastasis of intrahepatic cholangiocarcinoma. COX-2 may participate in a higher lymphatic invasion and metastasis via the vascular endothelial growth factor-C pathway.

Hepatitis B and C virus infections as possible risk factor for pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PAC) is a very aggressive and lethal cancer, with a very poor prognosis, because of absence of early symptoms, advanced stage at presentation, early metastatic dissemination and lack of both specific tests to detect its growth in the initial phases and effective systemic therapies. To date, the causes of PAC still remain largely unknown, but multiple lines of evidence from epidemiological and laboratory researches suggest that about 15-20% of all cancers are linked in some way to chronic infection, in particular it has been shown that several viruses have a role in human carcinogenesis. The purpose of this report is to discuss the hypothesis that two well-known oncogenic viruses, Human B hepatitis (HBV) and Human C hepatitis (HCV) are a possible risk factor for this cancer. Therefore, with the aim to examine the potential link between these viruses and PAC, we performed a selection of observational studies evaluating this association and we hypothesized that some pathogenetic mechanisms involved in liver carcinogenesis might be in common with pancreatic cancer development in patients with serum markers of present or past HBV and HCV infections. To date the available observational studies performed are few, heterogeneous in design as well as in end-points and with not univocal results, nevertheless they might represent the starting-point for future larger and better designed clinical trials to define this hypothesized relationship. Should these further studies confirm an association between HBV/HCV infection and PAC, screening programs might be justified in patients with active or previous hepatitis B and C viral infection.

Reduction in cancer risk by selective and nonselective cyclooxygenase-2 (COX-2) inhibitors

We conducted a series of epidemiologic studies to evaluate the chemopreventive effects of aspirin, ibuprofen, and selective cyxlooxygenase-2 (COX-2) inhibitors (coxibs) against cancers of the breast, colon, prostate, and lung. Composite results across all four cancer sites revealed that regular intake of 325 mg aspirin, 200 mg ibuprofen, or standard dosages of coxibs (200 mg celecoxib or 25 mg rofecoxib) produced risk reductions of 49%, 59%, and 64%, respectively. Use of coxibs for at least 2 years was associated with risk reductions of 71%, 70%, 55%, and 60% for breast cancer, colon cancer, prostate cancer and lung cancer, respectively. Effects of ibuprofen were similar to selective coxibs, and slightly stronger than aspirin. These observed effects are consistent with the relative COX-2 selectivity of ibuprofen, coxibs, and aspirin. Acetaminophen, an analgesic without COX-2 activity, had no effect. Overexpression of COX-2 and increased prostaglandin biosynthesis correlates with carcinogenesis and metastasis at most anatomic sites. These results indicate that regular intake of nonselective or selective COX-2 inhibiting agents protects against the development of major forms of cancer.

Celecoxib radiosensitizes the human cervical cancer HeLa cell line via a mechanism dependent on reduced cyclo-oxygenase-2 and vascular endothelial growth factor C expression

OBJECTIVE

The effects of celecoxib, a selective cyclo-oxygenase-2 (COX-2) inhibitor, on HeLa cervical cancer cell growth and radiosensitivity were investigated.

METHODS

Cytotoxicity was quantified using a 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium assay and effects on radiosensitivity were assessed using the lethal dose, quasithreshold dose, fraction surviving after 2 Gy irradiation and the radiosensitization ratio (SER, based on average lethal dose) determined using a single-hit multitarget model.

RESULTS

Celecoxib inhibited HeLa cell proliferation in a concentration- and time-dependent manner, with a half-maximal inhibitory concentration at 72 h of 44 μmol/l. Treatment with 20 μmol/l celecoxib for 72 h before irradiation was associated with an SER of 2.01. The SER of irradiated cells was 2.41 when treated with 40 μmol/l celecoxib before irradiation, 1.89 when treated simultaneously and 1.44 when treated after irradiation. Celecoxib downregulated COX-2 and vascular endothelial growth factor C (VEGF-C) expression evaluated immunohistochemically.

CONCLUSION

Celecoxib pretreatment radiosensitizes HeLa cells via a mechanism dependent on down-regulation of COX-2 and VEGF-C.

The interaction between hepatitis B virus X protein and AIB1 oncogene is required for the activation of NFκB signal transduction

We identified the interaction between HBV X (HBx) protein and the oncogene AIB1 (amplified in breast cancer 1). A serine/proline motif (SSPSPS) in HBx was found to be required for the interaction. Two LXD motifs [LLXX(X)L, X means any amino acids], LLRNSL and LLDQLHTLL in AIB1 were also found to be involved in the HBx-AIB1 interaction. The HBx-AIB1 interaction was important for the activation of NFκB signal transduction, the HBx mutant that did not interact with AIB1showed dramatically lower NFκB activation activity than the WT HBx. These findings contribute to the new understanding on signal transduction activation mechanisms of HBx.

Epigenetic deregulation of the COX pathway in cancer

Inflammation is a major cause of cancer and may condition its progression. The deregulation of the cyclooxygenase (COX) pathway is implicated in several pathophysiological processes, including inflammation and cancer. Although, its targeting with nonsteroidal antiinflammatory drugs (NSAIDs) and COX-2 selective inhibitors has been investigated for years with promising results at both preventive and therapeutic levels, undesirable side effects and the limited understanding of the regulation and functionalities of the COX pathway compromise a more extensive application of these drugs. Epigenetics is bringing additional levels of complexity to the understanding of basic biological and pathological processes. The deregulation of signaling and biosynthetic pathways by epigenetic mechanisms may account for new molecular targets in cancer therapeutics. Genes of the COX pathway are seldom mutated in neoplastic cells, but a large proportion of them show aberrant expression in different types of cancer. A growing body of evidence indicates that epigenetic alterations play a critical role in the deregulation of the genes of the COX pathway. This review summarizes the current knowledge on the contribution of epigenetic processes to the deregulation of the COX pathway in cancer, getting insights into how these alterations may be relevant for the clinical management of patients.

Angiogenic activity of hepatitis B and C viruses

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. The limited treatment options and poor prognosis of HCC patients underscore the importance of developing new therapeutic strategies. Infection with HBV and HCV are the major risk factors for developing HCC. While the precise molecular mechanisms that link HBV and HCV infections to the development and progression of HCC are not entirely understood, increasing evidence indicates that stimulation of angiogenesis by these viruses may contribute to HCC malignancy. In this review, we summarize the progress in understanding the role of HBV and HCV infection in liver and HCC angiogenesis, the mechanisms applied by these viruses to deregulate the angiogenic balance and the potential therapeutic options that come with this understanding.

Observation of Curative Efficacy and Prognosis following Combination Chemotherapy with Celecoxib in the Treatment of Advanced Colorectal Cancer

This study investigated the antitumour and chemosensitizing effects of celecoxib in the treatment of advanced colorectal cancer. A total of 90 patients were randomly divided into two groups: group CF was treated with a combination of celecoxib and the folinic acid-fluorouracil-oxaliplatin (FOLFOX4) regimen; and group F was treated with the FOLFOX4 regimen alone. Immunohistochemical analysis of tumour tissues for cyclooxygenase-2 (COX-2) protein was performed. With regard to short-term efficacy, the response and disease control rates were significantly greater in group CF than group F. A log-rank test showed that the 3-year survival rate was significantly greater in group CF than group F. It was concluded that the addition of celecoxib to the FOLFOX4 regimen increased the short-term efficacy and the 3-year survival rate, and improved the quality of life of patients with advanced colorectal cancer. The antitumour and chemosensitizing effects of celecoxib appeared to be independent of COX-2.

Endoplasmic reticulum stress induced by hepatitis B virus X protein enhances cyclo-oxygenase 2 expression via activating transcription factor 4

Chronic hepatitis B is a disease of the liver that can progress to cirrhosis and liver cancer. The HBx (hepatitis B virus X) protein of hepatitis B virus is a multifunctional regulator that induces ER (endoplasmic reticulum) stress by previously unknown mechanisms. ER stress plays a critical role in inflammatory induction and COX2 (cyclo-oxygenase 2) is an important mediator of this inflammation. In the present study, we demonstrate the molecular mechanisms of HBx on induction of ER stress and COX2 expression. In addition, HBx reduced expression of enzymes which are involved in mitochondrial β-oxidation of fatty acids and the mitochondrial inner membrane potential. The reduction in intracellular ATP levels by HBx induced the unfolded protein response and COX2 expression through the eIF2α (eukaryotic initiation factor 2α)/ATF4 (activating transcription factor 4) pathway. We confirmed that ATF4 binding to the COX2 promoter plays a critical role in HBx-mediated COX2 induction. The results of the present study suggest that HBV infection contributes to induction of hepatic inflammation through dysfunction of cellular organelles including the ER and mitochondria.

Carboxyl-terminal truncated HBx regulates a distinct microRNA transcription program in hepatocellular carcinoma development

BACKGROUND

The biological pathways and functional properties by which misexpressed microRNAs (miRNAs) contribute to liver carcinogenesis have been intensively investigated. However, little is known about the upstream mechanisms that deregulate miRNA expressions in this process. In hepatocellular carcinoma (HCC), hepatitis B virus (HBV) X protein (HBx), a transcriptional trans-activator, is frequently expressed in truncated form without carboxyl-terminus but its role in miRNA expression and HCC development is unclear.

METHODS

Human non-tumorigenic hepatocytes were infected with lentivirus-expressing full-length and carboxyl-terminal truncated HBx (Ct-HBx) for cell growth assay and miRNA profiling. Chromatin immunoprecipitation microarray was performed to identify the miRNA promoters directly associated with HBx. Direct transcriptional control was verified by luciferase reporter assay. The differential miRNA expressions were further validated in a cohort of HBV-associated HCC tissues using real-time PCR.

RESULTS

Hepatocytes expressing Ct-HBx grew significantly faster than the full-length HBx counterparts. Ct-HBx decreased while full-length HBx increased the expression of a set of miRNAs with growth-suppressive functions. Interestingly, Ct-HBx bound to and inhibited the transcriptional activity of some of these miRNA promoters. Notably, some of the examined repressed-miRNAs (miR-26a, -29c, -146a and -190) were also significantly down-regulated in a subset of HCC tissues with carboxyl-terminal HBx truncation compared to their matching non-tumor tissues, highlighting the clinical relevance of our data.

CONCLUSION

Our results suggest that Ct-HBx directly regulates miRNA transcription and in turn promotes hepatocellular proliferation, thus revealing a viral contribution of miRNA deregulation during hepatocarcinogenesis.

Hepatitis B virus X protein enhances COX-2 expression in human liver cell line L-02

AIM: To investigate the effect of hepatitis B virus X protein (HBx) on COX-2 expression in human liver cell line L-02.

METHODS: HBx expression vector pIRES2-AcGFP-HBx was constructed and transfected into L-02 cells. The expression of COX-2 mRNA and protein was detected by RT-PCR and Western blot, respectively. The effect of HBx protein on cell division and proliferation was evaluated by plotting cell growth curve and analyzing cell cycle. Moreover, pGL3-COX-2 plasmid, in which the COX-2 promoter has been linked to the luciferase reporter gene, was transfected into L-02 cells and luciferase activities were measured.

RESULTS: RT-PCR results revealed that HBx mRNA was expressed only in cells transfected with the HBx gene, and that COX-2 mRNA expression in cells transfected with the HBx gene was higher than that in cells untranfected or transfected with an empty vector (0.76 ± 0.12 vs 0.28 ± 0.04, 0.25 ± 0.03, both P < 0.01). Western blot analysis showed that HBx protein was expressed only in cells transfected with the HBx gene, and COX-2 protein expression in this group was higher than that in the two control groups. The proliferation of cells transfected with the HBx gene was faster than that of control cells (both P < 0.05). The numbers of cells in S and G2-M phases significantly increased while those in G₀-G₁ phase decreased in cells transfected with the HBx gene compared to control cells (all P < 0.05). The luciferase activity in cells transfected with the HBx gene was higher than that in control cells (1 675.2 ± 84.9 vs 657.7 ± 34.7, 739.3 ± 45.3, both P < 0.05).

CONCLUSION: HBx protein can enhance COX-2 expression by up-regulating the activity of COX-2 promoter and promote cell growth, division and proliferation in human liver cell line L-02.

Advances in understanding the role of cyclooxygenase-2 in the pathogenesis of liver diseases

Cyclooxygenase (COX) enzymes catalyze the rate limiting steps in prostaglandin synthesis and play an important role in inflammation, cell proliferation and apoptosis that are involved in the pathogenesis of many diseases. In recent years, great advances have been made in understanding the role of cyclooxygenase-2 in the pathogenesis of liver diseases. The use of selective cyclooxygenase-2 inhibitors provides a new avenue for clinical therapy of liver diseases. In this article, we will review recent advances in understanding the role of cyclooxygenase-2 in the pathogenesis of liver diseases.

Induction of cyclooxygenase-2 expression by hepatitis B virus depends on demethylation-associated recruitment of transcription factors to the promoter

BACKGROUND

The hepatitis B virus (HBV) is a major etiological factor of inflammation and damage to the liver resulting in hepatocellular carcinoma. Transcription factors play important roles in the disordered gene expression and liver injury caused by HBV. However, the molecular mechanisms behind this observation have not been defined.

RESULTS

In this study, we observed that circulating prostaglandin (PGE) 2 synthesis was increased in patients with chronic hepatitis B infection, and detected elevated cyclooxygenase (COX)-2 expression in HBV- and HBx-expressing liver cells. Likewise, the association of HBx with C/EBPβ contributed to the induction of COX-2. The COX-2 promoter was hypomethylated in HBV-positive cells, and specific demethylation of CpG dinucleotides within each of the two NF-AT sites in the COX-2 promoter resulted in the increased binding affinity of NF-AT to the cognate sites in the promoter, followed by increased COX-2 expression and PGE2 accumulation. The DNA methylatransferase DNMT3B played a key role in the methylation of the COX-2 promoter, and its decreased binding to the promoter was responsible for the regional demethylation of CpG sites, and for the increased binding of transcription factors in HBV-positive cells.

CONCLUSION

Our results indicate that upregulation of COX-2 by HBV and HBx is mediated by both demethylation events and recruitment of multiple transcription factors binding to the promoter.

Advances in understanding the biological roles of HBx

Hepatitis B virus (HBV) is the leading cause of liver cancer. Globally, there are over 350 million individuals chronically infected with HBV, and approximately 25% of these individuals will develop hepatocellular carcinoma (HCC). HBV is the prototype virus of the hepadnavirus family. The genome of HBV is circular and contains four open reading frames (ORFs). The HBx protein encoded by the X region of HBV is a multifunctional regulatory protein that possesses a wide transactivation activity and plays critical roles in regulating intracellular signal transduction, viral replication and transcription, cell proliferation and apoptosis, protein degradation, and heredity stability of hepatocytes. Due to its important roles in the development of chronic liver diseases, the research on the HBx protein has become a hot topic in recent years. In this paper, we will summarize the latest advances in understanding the biological roles of the HBx protein.

Increased expression of cyclooxygenase-2 is associated with the progression to cirrhosis

BACKGROUND/AIMS

To investigate the degree of cyclooxygenase-2 (COX-2) protein expression in chronic hepatitis and cirrhosis.

METHODS

COX-2 protein expression was evaluated in 43 cases of chronic hepatitis and 24 cases of cirrhosis using immunohistochemical techniques. The COX-2 immunohistochemical staining score was assessed using the scoring systems of Pazirandeh et al and Qiu et al. and each scoring system was based on a sum of the parameters of staining intensity and distribution.

RESULTS

The mean COX-2 expression scores in chronic hepatitis and cirrhosis were 2.5 ± 1.3 vs. 3.3 ± 1.1 (p = 0.008), and 3.2 ± 2.0 vs. 4.5 ± 1.7 (p = 0.006), respectively, based on the Pazirandeh et al. and Qiu et al. scoring systems. The percentage samples of high COX-2 expression score (4 to 5) in chronic hepatitis and cirrhosis were 16.3% vs. 45.8% (p = 0.022), and 23.3% vs. 50% (p = 0.021), respectively, based on the two scoring systems. The mean COX-2 expression scores based on the severity of hepatic fibrosis scored using Ishak's modified staging system (fibrosis score 0 to 3 vs. 4 to 6) were 2.4 ± 1.3 vs. 3.2 ± 1.1 (p = 0.009), and 3.1 ± 2.0 vs. 4.3 ± 1.8 (p = 0.009), respectively, based on the two scoring systems.

CONCLUSIONS

COX-2 expression was significantly higher in liver cirrhosis group than in chronic hepatitis. COX-2 expression scores according to Ishak's staging was significantly higher in the advanced fibrosis group. COX-2 may play a role in the progression of hepatic fibrosis.