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p53-independent apoptotic effects of the hepatitis B virus HBx protein in vivo and in vitro.
- Source :
-
Oncogene [Oncogene] 1998 Oct 22; Vol. 17 (16), pp. 2115-23. - Publication Year :
- 1998
-
Abstract
- The hepatitis B virus protein HBx is a promiscuous transactivator implicated in both cell growth and death and in the development of hepatocellular carcinoma. We recently reported that HBx can potentiate c-myc-induced liver oncogenesis in a transgenic model where low level expression of HBx induces no pathology. To assess if HBx could affect the hepatocyte turnover, we investigated the HBx-elicited apoptotic responses in transgenic livers and in primary hepatocyte cultures. Here we show that transgenic expression of HBx is associated with a twofold increase of spontaneous cell death in the mouse liver. The finding that apoptosis was enhanced to similar extents in HBx mice carrying homozygous p53 null mutations implied that functionally intact p53 was not required to transduce the death signal. A direct, dose-dependent apoptotic function of HBx was demonstrated in transient transfections of liver-derived cell lines. We further show that stable expression of HBx at low, presumably physiological levels in primary hepatocytes, induced cellular susceptibility to diverse apoptotic insults, including growth factor deprivation, treatment with anti-Fas antibodies or doxorubicine and oxidative stress. HBx expression, but not p53 status profoundly affected the commitment of cells to die upon apoptotic stimuli. These data strengthen the notion that HBX may contribute to HBV pathogenesis by enhancing apoptotic death in the chronically infected liver.
- Subjects :
- Animals
Cells, Cultured
Female
Gene Expression
Hepatitis B Antigens genetics
Hepatitis B Antigens physiology
Liver pathology
Liver virology
Male
Mice
Mice, Inbred C57BL
Mice, Transgenic
Trans-Activators genetics
Viral Regulatory and Accessory Proteins
Apoptosis
Hepatitis B virus physiology
Trans-Activators physiology
Tumor Suppressor Protein p53 physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0950-9232
- Volume :
- 17
- Issue :
- 16
- Database :
- MEDLINE
- Journal :
- Oncogene
- Publication Type :
- Academic Journal
- Accession number :
- 9798683
- Full Text :
- https://doi.org/10.1038/sj.onc.1202432