VZV REPLICATION IN VITRO IS PREVENTED BY ROSCOVITINE, AN INHIBITOR OF THE CELL CYCLE

S.L. Taylor and J.F. Moffat
Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY, USA

Replication of VZV is dependent on host cell DNA synthesis machinery that is present in the nucleus during S phase of the cell cycle. Roscovitine inhibits cyclin dependent kinases (cdk-1, cdk-2, and cdk-5) that are required for cell cycle progression. Our hypothesis is that agents such as roscovitine that block the cell cycle in G1 phase create a nuclear environment where VZV cannot replicate its DNA genome. The effect of roscovitine on VZV growth was tested in melanoma cells (MeWo). Results
demonstrate that the same concentration of roscovitine that blocks the cell cycle also prevents VZV replication and the effect is reversible. A concentration of 50uM roscovitine caused 75% of MeWo cells to accumulate in G1 phase as measured by propidium iodide staining of nuclear DNA. A sonicated preparation of VZV (Parent Oka strain) was adsorbed to MeWo cell monolayers, then treated with 25-100uM roscovitine for 24 hours. Infectious VZV was not detectable in samples treated with 50-100uM roscovitine and 25uM almost completely eliminated the virus. The removal
of roscovitine at 24 hours enabled VZV replication to resume at a rate similar to that of untreated cells. Compounds such as roscovitine that block the cell cycle have potential for anti-viral applications and have the added benefit that agents directed against cellular targets reduce the probability of resistant viral mutants arising.

Corresponding Author: Jennifer F. Moffat, Ph.D., Assistant Professor, Department of Microbiology and Immunology, SUNY Upstate Medical University, 750 East Adams Street, Syracuse, NY 13210, USA; moffatj@mail.upstate.edu