HBxAg增加p53蛋白在肝癌细胞内积聚

目的 进一步研究ＨＢＶｘ基因产物ＨＢｘＡｇ与ｐ５３蛋白的相互关系,探讨其在原发性肝癌发生中的作用机制。方法 以肝癌细胞株Ｈｅｐ３Ｂ为靶细胞,应用薄层层析法做报道基因氯霉素乙酰转移酶（ＣＡＴ）试验与ｐ５３和ＨＢｘ基因共转染,并构建了地塞米松诱导表达的ＨＢｘ基因质粒,用免疫荧光法观察ＨＢｘＡｇ表达对细胞内ｐ５３蛋白的影响。结果 应用ＨＢｘ基因与ｐＧ１３ＣＡＴ共转染,随ＨＢｘ量的增加而ＣＡＴ信号增强,免

HBxAg enhanced p53 protein accumulation in hepatoma cells

OBJECTIVE: In order to determine the interaction between HBxAg and p53 protein and its role in hepatocarcinogenesis. METHODS: Cotransfection was performed using reporter gene, chloramphenical acetyltransferase (CAT), p53 and HBVx gene, and dexamethasone inducible HBx plasmid pMAMHBx was constructed for the experiment. Human hepatoma cell line Hep3B was used as the target cell. The activity of HBxAg and p53 was detected by CAT assay and immunohistochemical staining after transient transfection. RESULTS: HBxAg could increase the accumulation of p53 protein in cells and enhance CAT expression. Immunohistochemical staining showed that p53 protein bound to HBxAg in the cytoplasm and formed a complex causing a partial block of the process of p53 during passing through the nuclear membrane from the cytoplasm. CONCLUSION: Data strongly suggested that HBxAg is capable of binding p53 and forms a protein-protein complex which might reduce or inactivate p53's antiproliferative activity and plays an important role in the pathogenesis of HBV-associated hepatocellular carcinoma.