RESUMO
AIMS: Hepatitis B surface antigen (HBsAg) seroclearance indicates a "functional cure" in chronic hepatitis B (CHB) virus infection. However, several cases of hepatocellular carcinoma (HCC) development have been reported after HBsAg seroclearance. We evaluated the potential of HBsAg and hepatitis B core-related antigen (HBcrAg), measured by the ultra-highly sensitive assays, in cases with HCC development after HBsAg seroclearance. METHODS: We enrolled 17 patients with CHB who achieved HBsAg seroclearance, defined by the conventional assay using Architect HBsAg QT kit (five HCC patients and 12 non-HCC patients). HBsAg and HBcrAg were measured in their stored serum samples using ultra-highly sensitive assays featuring "immunoassay for total antigen including complex via pretreatment (iTACT)" technology. RESULTS: All five patients who developed HCC were positive for HBsAg or HBcrAg by iTACT-HBsAg or iTACT-HBcrAg at all follow-up points. HBcrAg levels in the HCC group, using iTACT-HBcrAg, were significantly higher than those in the non-HCC group at HBsAg seroclearance (3.6 LogU/ml (2.8-4.2) versus 2.6 (<2.1-3.8), p = 0.020). The best cutoff value of iTACT-HBcrAg for predicting HCC development was 2.7 LogU/ml by receiver operating characteristic curve analysis. The prevalence of HBcrAg ≥2.7 in the HCC group was significantly higher than that in non-HCC group (100% [5/5] versus 33% [4/12], p = 0.029). CONCLUSIONS: Residual low viral antigen might predict HCC development even if HBsAg seroclearance was achieved according to a conventional assay. The results suggest that iTACT assays of HBsAg and HBcrAg would be useful for monitoring CHB patients.
RESUMO
Frequent observations of allelic loss in chromosomal band 4q21-22 in hepatocellular carcinoma (HCC) have suggested the presence of one or more tumor suppressor genes in this region. We screened HCC cell lines by reverse transcription-polymerase chain reaction (RT-PCR) to detect alterations in expression of genes within the region in question by examining expressed sequence tags located there. These experiments identified a full-length cDNA of 2311 bp in length encoding a novel, 182-amino-acid peptide belonging to the class of nucleosome assemble protein lacking nuclear localization signal sequence. Polyclonal antibody was raised by expression of a constructed recombinant glutathione S-transferase fusion protein. in vitro expression and Western blotting revealed that the novel protein distributed in cytoplasm. This gene showed loss or extreme decrease of expression in five of 13 HCC cell lines. We named it DRLM ('down-regulated in liver malignancy'). Our results suggest that loss of expression of DRLM at 4q21-22 may play an important role in human hepatocarcinogenesis.
Assuntos
Carcinoma Hepatocelular/genética , Cromossomos Humanos Par 4/genética , Neoplasias Hepáticas/genética , Proteínas/genética , Células 3T3 , Sequência de Aminoácidos , Animais , Sequência de Bases , Carcinoma Hepatocelular/patologia , Clonagem Molecular , DNA/química , DNA/genética , Regulação para Baixo , Etiquetas de Sequências Expressas , Regulação Neoplásica da Expressão Gênica , Proteínas de Fluorescência Verde , Células HeLa , Humanos , Neoplasias Hepáticas/patologia , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Camundongos , Dados de Sequência Molecular , Proteínas de Neoplasias , Proteínas Nucleares , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Células Tumorais CultivadasRESUMO
Although hepatitis C virus (HCV) is a well-known causative agent of hepatocellular carcinoma (HCC), the mechanism by which HCV induces HCC remains obscure. To elucidate the role of HCV in hepatocarcinogenesis, a model of hepatocyte injury was established using HCV core transgenic mice, which were developed using C57BL/6 mice transfected with the HCV core gene under control of the serum amyloid P component promoter. After 18-24 months, neither steatosis nor hepatic tumors were found in transgenic mice. The extent of hepatocyte injury and tumorigenesis were then examined in transgenic mice following repeated administration of carbon tetrachloride (CCl(4)) using various protocols (20%, 1/week; 10%, 2/week and 20%, 2/week). Serum alanine aminotransferase (ALT) levels did not differ among HCV core transgenic mice and non-transgenic littermates; however, after 40 weeks, hepatic adenomas preferentially developed in transgenic mice receiving 20% CCl(4) once weekly. Moreover, HCC was observed in transgenic mice receiving 2 weekly injections of a 20% solution of CCl(4), and was not observed in the non-transgenic control mice. In conclusion, the HCV core protein did not promote hepatic steatosis or tumor development in the absence of hepatotoxicity. However, the HCV core protein promoted adenoma and HCC development in transgenic mice following repeated CCl(4) administration. These results suggest that hepatotoxicity resulting in an increased rate of hepatocyte regeneration enhances hepatocarcinogenesis in HCV-infected livers. Furthermore, this experimental mouse model provides a valuable method with which to investigate hepatocarcinogenesis.