title: HBx or HCV core gene expression in HepG2 human liver cells results in a survival benefit against oxidative stress with possible implications for HCC development.
abstract: Hepatitis virus replication in the liver is often accompanied by inflammation resulting in the formation of reactive oxygen species (ROS) and nitric oxide (NO) and these may induce cell death. We investigated whether the expression of HBx or HCV core protein in HepG2 cells has an influence on the sensitivity of these cells for oxidative radicals. Our previous study, using the inducible HBV model of HepAD38, revealed that oxidative-stress-related genes are upregulated by virus replication. In the present study, we examined the intracellular pro-oxidant status with dichlorofluorescein (DCF) in HepG2 cell lines transfected with HBx, HbsAg and HCV core. Baseline intracellular oxidative levels were not different in the cell lines expressing viral proteins as compared to control. However, when these cells were exposed to H(2)O(2), the viral protein expressing cells, especially those expressing HBx, showed a reduced level of ROS. This suggests that HBx and HCV core transfected cells can convert H(2)O(2) to less reactive compounds at a higher rate than the control cells. When HBx or HCV core expressing cells were exposed to peroxynitrite (a highly reactive product formed under physiological conditions through interaction of superoxide (O(2)(-)) with NO) these cells were less sensitive to induction of cell death. In addition, these cell lines were less prone to cell death when exposed to H(2)O(2) directly. In conclusion, HBx and HCV core expression in HepG2 cells leads to a survival benefit under oxidative stress which in vivo can be induced during inflammation.
authors.affiliation: Laboratory of Hepatology, University Hospital Gasthuisberg, O&N Building Bus 703, Herestraat 49, Leuven, Belgium.
authors.forename: Tamara
authors.initials: T
authors.lastname: Severi
authors.forename: Sara
authors.initials: S
authors.lastname: Vander Borght
authors.forename: Louis
authors.initials: L
authors.lastname: Libbrecht
authors.forename: Lucas
authors.initials: L
authors.lastname: VanAelst
authors.forename: Frederik
authors.initials: F
authors.lastname: Nevens
authors.forename: Tania
authors.initials: T
authors.lastname: Roskams
authors.forename: David
authors.initials: D
authors.lastname: Cassiman
authors.forename: Johan
authors.initials: J
authors.lastname: Fevery
authors.forename: Chris
authors.initials: C
authors.lastname: Verslype
authors.forename: Jos F
authors.initials: JF
authors.lastname: van Pelt
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000502:physiology; D005562:Formazans / Q000737:chemistry; D018936:Hepatitis C Antigens / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008099:Liver / Q000378:metabolism / Q000821:virology; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D008856:Microscopy, Fluorescence; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000494:pharmacology; D015534:Trans-Activators; D014162:Transfection; D054334:Viral Regulatory and Accessory Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D005562:Formazans; D018936:Hepatitis C Antigens; D015534:Trans-Activators; D054334:Viral Regulatory and Accessory Proteins; C057628:hepatitis B virus X protein; D030421:Peroxynitrous Acid; C059088:1,5-bis(2-methoxy-4-nitro-5-sulfophenyl)-3-((phenylamino)carbonyl)formazan; D006861:Hydrogen Peroxide