Differential effects on apoptosis induction in hepatocyte lines by stable expression of hepatitis B virus X protein

被引:8
作者
Fiedler, Nicola
Quant, Ellen
Fink, Ludger
Sun, Jianguang
Schuster, Ralph
Gerlich, Wolfram H.
Schaefer, Stephan
机构
[1] Univ Rostock, Abt Virol, Inst Med Mikrobiol, D-18055 Rostock, Germany
[2] Univ Giessen, Inst Med Virol, D-35392 Giessen, Germany
[3] Univ Kiel, Innere Med Abt, D-24098 Kiel, Germany
[4] Univ Giessen, Zentrum Innere Med, D-35390 Giessen, Germany
[5] Chinese Acad Agr Sci, Inst Agr Resources & Reg Planning, Beijing 100081, Peoples R China
关键词
apoptosis; hepatitis B virus; hepatocyte lines;
D O I
10.3748/wjg.v12.i29.4673
中图分类号
R57 [消化系及腹部疾病];
学科分类号
摘要
AIM: Hepatitis B virus protein X (HBx) has been shown to be weakly oncogenic in vitro. The transforming activities of HBx have been linked with the inhibition of several functions of the tumor suppressor p53. We have studied whether HBx may have different effects on p53 depending on the cell type. METHODS: We used the human hepatoma cell line HepG2 and the immortalized murine hepatocyte line AML12 and analyzed stably transfected clones which expressed physiological amounts of HBx. P53 was induced by UV irradiation. RESULTS: The p53 induction by UV irradiation was unaffected by stable expression of HBx. However, the expression of the cyclin kinase inhibitor p21(waf/cip/sdi) which gets activated by p53 was affected in the HBx transformed cell line AML12-HBx9, but not in HepG2. In AML-HBx9 cells, p21(waf/cip/sdi)-protein expression and p21(waf/cip/sdi) transcription were deregulated. Furthermore, the process of apoptosis was affected in opposite ways in the two cell lines investigated. While stable expression of HBx enhanced apoptosis induced by UV irradiation in HepG2-cells, apoptosis was decreased in HBx transformed AML12-HBx9. P53 repressed transcription from the HBV enhancer I, when expressed from expression vectors or after induction of endogenous p53 by UV irradiation. Repression by endogenous p53 was partially reversible by stably expressed HBx in both cell lines. CONCLUSION: Stable expression of HBx leads to deregulation of apoptosis induced by UV irradiation depending on the cell line used. In an immortalized hepatocyte line HBx acted anti-apoptotic whereas expression in a carcinoma derived hepatocyte line HBx enhanced apoptosis. (c) 2006 The WJG Press. All rights reserved.
引用
收藏
页码:4673 / 4682
页数:10
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