Up-regulation of NORPEG Gene in Hepatitis C Virus Proteins Expressing Cells

• Main Authors: Jia-Ying Lee, 李佳穎
• Other Authors: Ming-Fu Chang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/32413407731226328891

碩士 === 國立臺灣大學 === 生物化學暨分子生物學研究所 === 92 === Primary hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. Despite the development of novel therapeutic methods in recent years, prognosis of advanced HCC is still poor. Major risk factors for HCC are chronic hepatitis resulting from infection with hepatitis B or C virus, and exposure to various exogenous carcinogens including aflatoxin B1. In this study, the relationship between HCV and HCC is under investigation. Recent studies identified hypermutation of p53 gene in HCV-infected B cell lymphoma. To understand the molecular mechanisms of HCV involved in the hepatocarcinogenesis, mutation status of p53 in HCV replicon-containing cell line and the parental Huh7 cells were analyzed. Two mutations were found in the p53 gene of Huh7 and HCV replicon cells continually passaged for 12, 22, 47, 80 and 132 generations. C to T mutation at nucleotide 411 resulted in a silent mutation, whereas the A to G mutation at nucleotide 793 caused a tyrosine to cysteine mutation at amino acid residue 220. No additional mutations were observed in the HCV replicon cell lines. On the other hand, by performing DNA microarray analysis, our laboratory have previously identified a novel gene NORPEG that was up-regulated in the HCV replicon-containing Huh7 cell line (the 33rd passage). This result was confirmed by real-time PCR analysis of HCV replicon cell lines (the 12th and the 22nd passages). NORPEG gene was recently reported to be up-regulated in HCC, but its function is still not fully understood. Antibodies specific to NORPEG protein were generated. Western blot analysis demonstrated that the expression levels of NORPEG protein were higher in the human hepatoma cell lines Huh7 and HepG2 than in non-hepatic HeLa cells. In addition, the expression level of NORPEG protein was also higher in HCV core protein-expressing HeLa cells (Core-6 and Core-13) when compared to the parental HeLa cells. These results suggest that NORPEG may have a role involved in the pathogenesis of the core protein and the hepatocarcinigenesis of HCV.