Hepatitis B virus X induces cell proliferation in the hepatocarcinogenesis via up-regulation of cytoplasmic p21 expression.

BACKGROUND: Hepatitis B virus X protein (HBx) has been shown to induce hepatocarcinogenesis by disrupting the functions of intracellular molecules. Cyclin-dependent kinase inhibitor p21 (Cip1/WAF1), known as a tumour-suppressor gene, has been reported to have paradoxical function, that is, acting as an oncogene, particularly when expressed in the cytoplasm. The effects of HBx on the expression and function of p21 also remain controversial. AIMS: We attempted to investigate the role of HBx in the hepatocarcinogenic process, focusing on the association with this paradoxical function of p21. The results obtained were further verified with experiments using the antihepatocarcinogenic action of interferon (IFN)-ß. METHODS: HBx transgenic mice (Xg) and HBx-transfected hepatoma cell lines were used. Intracellular localization of p21 was determined by Western blot analysis and immunofluorescence. RESULTS: Xg and HBx-transfected cells exhibited increased expression of p21. Up-regulation of p21 was positively correlated with the expression of cyclin D1 and inactive phosphorylation of retinoblastoma protein (pRb). These HBx-induced cell proliferative responses were cancelled by knockdown of p21, which resulted in growth reduction in HBx-expressing cells, suggesting the oncogenic properties of HBx-induced p21. HBx induced accumulation of p21 in the cytoplasm, and activation of PKCα was involved. Finally, IFN-ß-treated Xg liver, as well as hepatoma cells, showed a shift of cytoplasmic p21 to the nucleus, accompanied by the abrogation of HBx-induced oncogenic modulation. CONCLUSIONS: Our results suggest that HBx induces hepatocarcinogenesis via PKCα-mediated overexpression of cytoplasmic p21 and IFN-ß suppressed these molecular events by shifting p21 to the nucleus.

Characterization of elevated alanine aminotransferase levels during pegylated-interferon α-2b plus ribavirin treatment for chronic hepatitis C.

AIM: Elevation of alanine aminotransferase (ALT) levels during pegylated-interferon (peg-IFN) plus ribavirin therapy in patients with chronic hepatitis C [CHC] is a problem that cannot be disregarded. The aim of this study is to assess the frequency and to characterize clinical parameters of this phenomenon. METHODS: Two hundred and thirty-five (235) CHC patients with genotype 1b receiving peg-IFN α-2b plus ribavirin therapy were analyzed. Clinical parameters that may be associated with abnormal ALT values during treatment and therapy outcomes were evaluated statistically. One hundred and sixteen (116) patients treated with peg-IFN α-2a plus ribavirin were also included for partial analysis. RESULTS: Abnormal ALT values during treatment were observed in 23.0% of patients. It was observed in 14.5% of those with sustained virological response (SVR) and 17.8% of those with relapse, in whom viral clearance was observed during therapy. Multivariate logistic regression analysis revealed that pretreatment ALT values, therapy outcome, and body mass index (BMI) were significant factors related to abnormal ALT values during treatment. Abnormal ALT values during treatment became normal in SVR patients at 6 months after the completion of treatment, but not in NR (non-response) patients. Mean ALT values were significantly higher at some time points during treatment in patients treated with α-2a when compared to those treated with α-2b. CONCLUSION: Abnormal ALT values during peg-IFN plus ribavirin treatment are observed relatively frequently, even in patients without detectable HCV RNA. Direct or indirect involvement of drugs is considered as one possible cause.

Very-Low-Dose Pegylated Interferon a2a Plus Ribavirin Therapy for Advanced Liver Cirrhosis Type C: A Possible Therapeutic Alternative without Splenic Intervention.

Despite the recent progress in interferon (IFN) therapies for chronic hepatitis C, liver cirrhosis remains refractory. One of the major obstacles to successful IFN therapy is low platelet count. Currently, splenic interventions, such as partial splenic embolization (PSE) or surgical splenectomy, have been applied effectively and make standard IFN therapy possible. However, there may be a group of patients with low platelet counts who can be treated without splenic intervention. We here report two patients with advanced type C liver cirrhosis who were successfully treated using very-low-dose pegylated interferon a2a plus ribavirin. One patient had a very low platelet count (2.5 x 10(4)/mul) due to splenomegaly before treatment. However, pretreatment serum HCV titers were low in both patients and early viral responses were obtained in both. Because PSE or splenectomy may still have some safety concerns, this attenuated IFN treatment protocol can be an alternative therapeutic option for patients with advanced type C liver disease, but good virological factors for sustained virological response.

Progression of hypermethylation of the p16(INK4A) gene from normal liver to nontumorous liver and hepatocellular carcinoma: an evaluation using quantitative PCR analysis.

The aim of this study was to determine to what extent hypermethylation of the p16(INK4A) (p16) gene promoter is increased in nontumorous liver tissues compared with in normal liver, using two quantitative methylation-specific polymerase chain reaction (MS-PCR) methods and a bisulfite sequencing method. Methylation of the p16 gene was detected more frequently in nontumorous liver than in normal liver using the TaqMan PCR method. Methylation indices also were significantly higher in nontumorous than in normal liver. However, the bisulfite sequencing method did not detect significantly more methylation of the p16 gene in nontumorous than normal liver, nor was there a significant difference in the level of p16 mRNA. There may be a greater proportion of cells which contain methylated p16 in nontumorous than in normal liver. However, the difference was so small that the functional relevance to hepatocarcinogenesis remains elusive.

Temporal treatment with interferon-beta prevents hepatocellular carcinoma in hepatitis B virus X gene transgenic mice.

BACKGROUND/AIMS: The preventive effect of interferon (IFN) against hepatocellular carcinoma (HCC) has been confirmed clinically. We sought to determine whether the temporal administration of IFN-beta prevents hepatocarcinogenesis in a mouse model where HCC develops without necroinflammation. METHODS: Hepatocarcinogenic mice that are transgenic for the hepatitis B virus X gene (HBx-Tg) were treated with IFN-beta or saline (control) for three months, from 3 to 6 months of age, and the incidence of HCC was determined at 18 months of age. The effects of IFN-beta on DNA synthesis and apoptosis were tested. RESULTS: The incidence of HCC was significantly lower in the IFN-beta-treated mice than the controls (0 vs. 50%, P<0.01). Inhibition of DNA synthesis in hepatocytes by IFN-beta was observed in the livers of HBx-Tg, without any significant induction of apoptosis. Although the treatment of IFN-beta was temporal, the number of hepatocytes with DNA synthesis remained lower 3 and 12 months later in life. CONCLUSIONS: Temporal administration of IFN-beta has a significant preventive effect on the occurrence of HCC in a mouse model where HCC develops without inflammation. The mechanisms are the inhibition of DNA synthesis and cell cycle progression of hepatocytes.

Successful treatment with lamivudine may correlate with reduction of serum ferritin levels in the patients with chronic hepatitis and liver cirrhosis type B.

PURPOSE: To study the changes in serum ferritin levels in lamivudine (LAM)-treated patients with chronic hepatitis and liver cirrhosis type B and determine whether successful treatment with LAM results in a reduction of serum ferritin levels. METHODS: Thirty patients with chronic hepatitis B virus (HBV) infection were followed prospectively during their treatment with LAM for 12 months. Serum HBV DNA, ferritin levels, and emergence of YMDD mutants were monitored. A case of severe liver cirrhosis with hepatic hemosiderosis that was treated successfully with LAM also is shown as a representative case. RESULTS: Serum alanine aminotransferase and ferritin levels decreased significantly more in the patients treated with LAM without YMDD mutants (n = 23) than those with mutants (n = 7). Hepatic hemosiderosis along with serum iron markers improved greatly in the representative patient. CONCLUSION: Successful treatment with LAM may reduce serum ferritin levels and improve hepatic siderosis in a subset of patients with chronic HBV infection.

Early upsurge in anti-HBs titer possibly caused by the immunomodulative, not by the mutagenetic effect of interferon and ribavirin.

A patient with chronic hepatitis B and C undergoing treatment with interferon and ribavirin showed an upsurge in hepatitis B virus surface antibody (anti-HBs) titer, accompanied by a decrease in hepatitis B virus surface antigen (HBsAg) during the early treatment phase. Simultaneously, elevation of alanine aminotransferase (ALT) was observed. Subsequently, the hepatitis B virus (HBV) DNA titer decreased and HBV e antigen (HBeAg) to anti-HBe seroconversion occurred. The anti-HBs titer gradually returned to the pretreatment level after cessation of ribavirin treatment and HBV-DNA became undetectable. We found no nucleotide mutations in HBV-DNA that could explain the sudden elevation in anti-HBs titer. The appearance of anti-HBs was considered to be a break in immune tolerance against some epitopes in HBsAg, possibly the r epitope, stimulated by interferon/ribavirin treatment. The immunomodulatory effect of ribavirin might have caused this unexpected early immune response to HBsAg that preceded seroconversion to anti-HBe.