ABSTRACT
Unlike other forms of hepatocellular carcinoma (HCC), HCC induced by hepatitis B virus (HBV) infection shows a poor prognosis after conventional therapies. HBV induces liver cirrhosis and HCC. Many researchers have made efforts to find new substances that suppress the activity of HBV. Curcuma longa Linn (CLL) has been used for traditional medicine and food in Asia, especially in India, and has shown chemopreventive effects in a HBV-related in vitro model. This in vivo study was designed to seek the chemopreventive effects of CLL and its mechanisms. CLL mixture concentrated with dextrose water by boiling was lyophilized. CLL extracts were administrated to HBV X protein (HBx) transgenic mice aged 4 weeks for 2 to 4 weeks and aged 6 months for 3 months. After administration, histological changes in the liver tissue and expression of HBx-related genes were investigated. CLL-treated mice showed less visceral fat, a smaller liver/body weight ratio and delayed liver pathogenesis. Proliferating cell nuclear antigen (PCNA) expression was also increased in CLL-treated HBx transgenic mice, indicating regeneration of damaged liver tissue. CLL treatment decreased expression of HBx and increased p21 and cyclin D1 in livers of HBx transgenic mice. In addition, p-p53 was increased after CLL treatment. These results suggest that CLL can have beneficial effects on the early and late stages of liver pathogenesis, preventing and delaying liver carcinogenesis. This drug should be considered as a potential chemopreventive agent for HBV-related hepatocarcinogenesis.
Subject(s)
Carcinoma, Hepatocellular/prevention & control , Curcuma/chemistry , Liver Neoplasms, Experimental/prevention & control , Liver/drug effects , Liver/pathology , Plant Extracts/pharmacology , Trans-Activators/genetics , Animals , Blood Glucose/drug effects , Body Weight/drug effects , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Proliferation/drug effects , Chemoprevention/methods , Cyclin-Dependent Kinase Inhibitor p21/genetics , Cyclin-Dependent Kinase Inhibitor p21/metabolism , Female , Gene Expression/drug effects , Gene Expression/genetics , Hepatocytes/drug effects , Hepatocytes/metabolism , Hepatocytes/pathology , Intra-Abdominal Fat/drug effects , Liver/metabolism , Liver Neoplasms, Experimental/metabolism , Liver Neoplasms, Experimental/pathology , Liver Regeneration/drug effects , Male , Mice , Mice, Inbred C57BL , Mice, Inbred CBA , Mice, Transgenic , Organ Size/drug effects , Phosphorylation/drug effects , Plant Extracts/administration & dosage , Plant Extracts/isolation & purification , Plant Extracts/therapeutic use , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Viral Regulatory and Accessory ProteinsABSTRACT
In this study we investigated the effect of ginseng saponins on the p53-dependent apoptosis in NIH3T3 cells exposed to methyl methanesulfonate (MMS), an alkylating agent. Trypan blue exclusion assay, cell morphology studies, and apoptotic index determined by acridine orange staining showed that the postincubation of MMS-exposed cells in medium containing diol- (PD) or triol-type (PT) ginseng saponins potentiate the apoptotic cell death. FACS analysis indicated that the increased apoptotic cell population in the saponin-postincubation group was accompanied by the accumulation of cells in G0/G1 phase. By Western blot analyses it was demonstrated that postincubation of saponins increases the expression of p53 and p21 in MMS-exposed cells but decreased that of CDK2, cyclin E and D1, and PCNA. The upregulation of p53 and p21 and downregulation of CDK2 was shown to be p53-dependent in experiments using the p53 antisense oligonucleotide. These results suggest that ginseng saponins contain components potentiating the apoptosis of MMS-exposed NIH3T3 cells via p53 and p21 activation, accompanied with by downregulation of cell cycle-related protein expression.