Inhibition of hepatitis B virus production associated with high levels of intracellular viral DNA intermediates in iron-depleted HepG2.2.15 cells

Backgrounds/Aims: The effects of iron-depletion on hepatitis B virus (HBV) replication were examined in HepG2.2.15 cells. Methods: Proliferating cells were iron-depleted with desferrioxamine (DFO), at 20 or 100 muM for 48 h. Levels of viral mRNAs, cytoplasmic DNA replicat ive intermediates and virion production were examined. A comparative study was performed with hydroxyurea, a specific inhibitor of ribonucleotide redu ctase. Results: In desferrioxamine treated cells, virion production is dramaticall y decreased, while viral replicative intermediates accumulate in the cytopl asm, DFO, like hydroxyurea, blocks cell cycle progression in the G1/S trans ition or S phase with a corresponding 2-fold increase of viral mRNAs. As ex pected, hydroxyurea leads to a strong reduction of virion production associ ated with low levels of intracellular replicative intermediates, Conclusions: These results strongly suggest that iron depletion affects the HDV life cycle indirectly through the cell cycle arrest and directly throu gh the inhibition of the viral DNA secretion. They also Indicate the need t o re-evaluate with caution the iron depletion protocols on HBV infected pat ients since a decrease of viral markers in the serum following iron-depleti on may not reflect a decrease of viral replicative forms, but on the contra ry, could be associated with active viral DNA synthesis. (C) 2001 European Association for the Study of the Liver. Published by Else vier Science B.V. All rights reserved.