Roscovitine, a cyclin-dependent kinase inhibitor, prevents replication of varicella-zoster virus.
Understanding the interactions between varicella-zoster virus (VZV) and host cells can be addressed by using small molecule inhibitors of cellular enzymes. Roscovitine (Rosco) is a purine derivative that inhibits cyclin-dependent kinase 1 (cdk1), cdk2, cdk5, cdk7, and cdk9, which are key regulators of the cell cycle and transcription. Herpesviruses are known to interact with cell cycle proteins; thus, the antiviral effects of Rosco on VZV growth were evaluated. In a plaque reduction assay, 25 micro M Rosco prevented VZV replication, and the antiviral effect was reversible for at least up to 24 h posttreatment. Rosco also reduced expression of the major transactivator, IE62, over 48 h. Confocal microscopy studies indicated that Rosco caused the immediate-early proteins ORF4 and IE62 to abnormally localize in infected cells and prevented cell-cell spread of VZV over 48 h. Rosco was found to inhibit VZV DNA synthesis as measured by real-time PCR, and this technique was used to estimate the 50% effective concentration (EC(50)) of 14 micro M. This value was close to the EC(50) estimate of 12 micro M determined from plaque reduction assays. At 25 micro M, Rosco was not cytotoxic over 48 h in a neutral red uptake assay, and proliferation was slowed as the cells accumulated in a G(2)-like state. These results demonstrate the importance of cdk's in VZV replication and suggest that cdk inhibitors could serve as useful VZV antivirals.
Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, New York, USA.
Shannon L
SL
Taylor
Paul R
PR
Kinchington
Andrew
A
Brooks
Jennifer F
JF
Moffat
D000998:Antiviral Agents / Q000494:pharmacology*; D017209:Apoptosis; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors*; D014645:Herpesvirus 3, Human / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D017874:Immediate-Early Proteins / Q000187:drug effects / Q000378:metabolism; D011687:Purines / Q000494:pharmacology*; D000077546:Roscovitine; D010948:Viral Plaque Assay; D014779:Virus Replication / Q000187:drug effects*
D000998:Antiviral Agents; D017874:Immediate-Early Proteins; D011687:Purines; D000077546:Roscovitine; D018844:Cyclin-Dependent Kinases