Structural and functional alterations of alpha satellite DNA in human hepatocellular carcinoma

人类肝细胞癌发生的分子机制尚未阐明。我们先前发现乙型肝炎病毒（HBV）的基因组DNA被整合到位于人肝癌细胞染色体着丝粒区域的α卫星DNA中。我们还发现，α卫星DNA的初级结构发生了与HBV DNA整合相关的重排。由于在肝细胞中未发现这种DNA改变，我们认为α卫星DNA的重排可能参与了肝细胞癌的发展。我们详细分析了重排α卫星DNA的初级结构。结果表明，DNA经历了与HBV整合相关的反向复制。为了研究重排α卫星DNA在肝癌发生中的可能功能，我们使用人类二倍体细胞系测试了克隆的重排α卫星DNA （pYSC）的细胞转化活性。到目前为止，我们还没有令人信服的证据证明重排的α卫星DNA具有细胞转化活性。慢性乙型肝炎抗病毒治疗的目标之一是预防肝细胞癌的发展。已知慢性乙型肝炎患者HBV基因组整合到肝细胞染色体中。为了研究HBV在抗病毒治疗过程中是否会发生基因型突变，这种突变病毒是否可能整合到肝细胞中，以及这种变异病毒的整合是否与野生型HBV不同，从而导致肝细胞癌的发生。我们检查了拉米夫定治疗期间HBV基因型突变的发生情况。结果表明，这些突变发生在一些患者身上。目前，我们正在研究这种突变HBV在通过针活检获得的肝组织中的整合。少

Molecular mechanisms of the development of human hepatocellular carcinoma have not been elucidated. We previously found that genomic DNA of hepatitis B virus (HBV) was integrated into alpha satellite DNA located in the centromeric region of chromosomes in human hepatocellular carcinoma cells. We also found that the primary structure of the alpha satellite DNA underwent rearrangement associated with the HBV DNA integration. Because such DNA alterations were not identified in hepatocytes, we considered that the rearrangement of the alpha satellite DNA might have been involved in the development of hepatocellular carcinoma. We analyzed in detail the primary structure of the rearranged alpha satellite DNA. The results showed that the DNA underwent an inverted duplication associated with the HBV integration. To examine possible functions of the rearranged alpha satellite DNA for the development of hepatocellular carcinoma, we tested cell-transforming activity of the cloned, rearranged alpha … More satellite DNA (pYSC) using human diploid cell lines. Up to the present, we have failed in having convincing evidence that the rearranged alpha satellite DNA has the cell-transforming activity.One goal of antiviral treatment against chronic hepatitis B is to prevent the development of hepatocellular carcinoma. It has been known that HBV genomes are integrated into chromosomes of hepatocytes in chronic hepatitis B. To investigate whether genotypic mutations of HBV would occur during antiviral treatment, whether integration of such mutant viruses may be integrated into hepatocytes, and whether integration of such variant viruses may differ from that of wild-type HBV for the contribution to the development of hepatocellular carcinoma, we examined the occurrence of genotypic mutations of HBV while on lamivudine treatment. The results demonstrated that the mutations occurred in some of patients. Currently, we are examining the integration of such mutant HBV in the liver tissue obtained through needle biopsy. Less