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.
Taylor
Shannon L
SL
Department of Microbiology and Immunology, State University of New York Upstate Medical University, Syracuse, New York, USA.
Kinchington
Paul R
PR
Brooks
Andrew
A
Moffat
Jennifer F
JF
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