title: Inhibition of human cytomegalovirus replication by artemisinins: effects mediated through cell cycle modulation.
abstract: Artemisinin-derived monomers and dimers inhibit human cytomegalovirus (CMV) replication in human foreskin fibroblasts (HFFs). The monomer artesunate (AS) inhibits CMV at micromolar concentrations, while dimers inhibit CMV replication at nanomolar concentrations, without increased toxicity in HFFs. We report on the variable anti-CMV activity of AS compared to the consistent and reproducible CMV inhibition by dimer 606 and ganciclovir (GCV). Investigation of this phenomenon revealed that the anti-CMV activity of AS correlated with HFFs synchronized to the G0/G1 stage of the cell cycle. In contact-inhibited serum-starved HFFs or cells arrested at early/late G1 with specific checkpoint regulators, AS and dimer 606 efficiently inhibited CMV replication. However, in cycling HFFs, in which CMV replication was productive, virus inhibition by AS was significantly reduced, but inhibition by dimer 606 and GCV was maintained. Cell cycle analysis in noninfected HFFs revealed that AS induced early G1 arrest, while dimer 606 partially blocked cell cycle progression. In infected HFFs, AS and dimer 606 prevented the progression of cell cycle toward the G1/S checkpoint. AS reduced the expression of cyclin-dependent kinases (CDK) 2, 4, and 6 in noninfected cycling HFFs, while the effect of dimer 606 on these CDKs was moderate. Neither compound affected CDK expression in noninfected contact-inhibited HFFs. In CMV-infected cells, AS activity correlated with reduced CDK2 levels. CMV inhibition by AS and dimer 606 also correlated with hypophosphorylation (activity) of the retinoblastoma protein (pRb). AS activity was strongly associated with pRb hypophosphorylation, while its reduced anti-CMV activity was marked by pRb phosphorylation. Roscovitine, a CDK2 inhibitor, antagonized the anti-CMV activities of AS and dimer 606. These data suggest that cell cycle modulation through CDKs and pRb might play a role in the anti-CMV activities of artemisinins. Proteins involved in this modulation may be identified and targeted for CMV inhibition.
authors: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Sujayita
authors: S
authors: Roy
authors: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Ran
authors: R
authors: He
authors: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Arun
authors: A
authors: Kapoor
authors: Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
authors: Michael
authors: M
authors: Forman
authors: Department of Chemistry, School of Arts and Sciences, The Johns Hopkins University, Baltimore, Maryland, USA.
authors: Jennifer R
authors: JR
authors: Mazzone
authors: Department of Chemistry, School of Arts and Sciences, The Johns Hopkins University, Baltimore, Maryland, USA Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors: Gary H
authors: GH
authors: Posner
authors: Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA boger@jhmi.edu.
authors: Ravit
authors: R
authors: Arav-Boger
mesh_terms: D000962:Antimalarials / Q000494:pharmacology*; D000998:Antiviral Agents / Q000494:pharmacology*; D037621:Artemisinins / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects*; D002478:Cells, Cultured; D051357:Cyclin-Dependent Kinase 2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D051358:Cyclin-Dependent Kinase 4 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D051361:Cyclin-Dependent Kinase 6 / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D003587:Cytomegalovirus / Q000187:drug effects*; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000821:virology; D016193:G1 Phase / Q000187:drug effects; D015774:Ganciclovir / Q000494:pharmacology; D006801:Humans; D010766:Phosphorylation; D011687:Purines / Q000494:pharmacology; D016192:Resting Phase, Cell Cycle / Q000187:drug effects; D016160:Retinoblastoma Protein / Q000378:metabolism; D000077546:Roscovitine; D014779:Virus Replication / Q000187:drug effects
chemical_list: D000962:Antimalarials; D000998:Antiviral Agents; D037621:Artemisinins; D004791:Enzyme Inhibitors; D011687:Purines; D016160:Retinoblastoma Protein; D000077546:Roscovitine; C031327:artemisinin; D051357:Cyclin-Dependent Kinase 2; D051358:Cyclin-Dependent Kinase 4; D051361:Cyclin-Dependent Kinase 6; D015774:Ganciclovir