title: Inhibitory effect of 2'-substituted nucleosides on hepatitis C virus replication correlates with metabolic properties in replicon cells.
abstract: Nucleosides have been widely used in the treatment of viral diseases, but relatively few have been identified as inhibitors of hepatitis C virus (HCV). The modified ribonucleosides, 2'-C-methyl-adenosine and 2'-O-methyl-cytidine, are potent inhibitors of HCV replication which specifically target the NS5B polymerase. Herein, a more extensive characterization of the effect of these compounds upon HCV replication in subgenomic replicons is reported. A highly selective antireplicative effect induced by the nucleosides in replicon-containing cell lines was maintained during an exponential growth period with potencies which paralleled the reduction of both positive- and negative-strand RNA replication. Moreover, the inhibitory effect closely correlated with the intrinsic metabolic properties of differing replicon clonal lines. Interestingly, while 2'-C-methyl-adenosine elicited similar inhibitory potencies in different cell lines, 2'-O-methyl-cytidine was found to be inactive in one replicon cell line tested, although the corresponding triphosphates comparably inhibited the in vitro activity of replication complexes isolated from these cells and the activity of NS5B polymerase using synthetic templates. The lack of antireplicative effect, attributed to poor intracellular conversion of the 2'-O-methyl-cytidine nucleoside to the active 5'-triphosphate, was reversed using a monophosphate prodrug. Thus, although replicon cells are useful for evaluating the effect of inhibitors upon HCV replication, these findings have important implications for their use in the identification and characterization of nucleosides and other chemotherapeutic agents requiring cellular metabolism.
authors.affiliation: Department of Research, Merck and Co., WP26-265, West Point, PA 19486, USA.
authors.forename: Joanne E
authors.initials: JE
authors.lastname: Tomassini
authors.forename: Krista
authors.initials: K
authors.lastname: Getty
authors.forename: Mark W
authors.initials: MW
authors.lastname: Stahlhut
authors.forename: Sung
authors.initials: S
authors.lastname: Shim
authors.forename: Balkrishen
authors.initials: B
authors.lastname: Bhat
authors.forename: Anne B
authors.initials: AB
authors.lastname: Eldrup
authors.forename: Thazha P
authors.initials: TP
authors.lastname: Prakash
authors.forename: Steven S
authors.initials: SS
authors.lastname: Carroll
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Flores
authors.forename: Malcolm
authors.initials: M
authors.lastname: MacCoss
authors.forename: Daniel R
authors.initials: DR
authors.lastname: McMasters
authors.forename: Giovanni
authors.initials: G
authors.lastname: Migliaccio
authors.forename: David B
authors.initials: DB
authors.lastname: Olsen
mesh_terms: D000998:Antiviral Agents / Q000494:pharmacology; D015152:Blotting, Northern; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D016174:Hepacivirus / Q000187:drug effects*; D008968:Molecular Conformation; D023282:Nuclease Protection Assays; D009705:Nucleosides / Q000494:pharmacology*; D011355:Prodrugs / Q000494:pharmacology; D012367:RNA, Viral / Q000096:biosynthesis / Q000235:genetics; D012324:RNA-Dependent RNA Polymerase / Q000378:metabolism; D012093:Replicon / Q000235:genetics*; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects*
chemical_list: D000998:Antiviral Agents; D009705:Nucleosides; D011355:Prodrugs; D012367:RNA, Viral; D012324:RNA-Dependent RNA Polymerase