ABSTRACT
β-
d
-2′-Deoxy-2′-fluoro-2′-
C
-methylcytidine (PSI-6130) is a potent inhibitor of hepatitis C virus (HCV) RNA replication in an HCV replicon assay. The 5′-triphosphate of PSI-6130 is a competitive inhibitor of the HCV RNA-dependent RNA polymerase (RdRp) and acts as a nonobligate chain terminator. Recently, it has been shown that the metabolism of PSI-6130 also results in the formation of the 5′-triphosphate of the uridine congener, β-
d
-2′-deoxy-2′-fluoro-2′-
C
-methyluridine (PSI-6206; RO2433). Here we show that the formation of the 5′-triphosphate of RO2433 (RO2433-TP) requires the deamination of PSI-6130 monophosphate and that RO2433 monophosphate is subsequently phosphorylated to the corresponding di- and triphosphates by cellular UMP-CMP kinase and nucleoside diphosphate kinase, respectively. RO2433-TP is a potent inhibitor of the HCV RdRp; however, both enzymatic and cell-based assays show that PSI-6130 triphosphate is a more potent inhibitor of the HCV RdRp than RO2433-TP.
摘要
β-
d
-2′-Deoxy-2′-fluoro-2′-
C
-甲基胞苷(PSI-6130)在 HCV 复制子试验中是一种有效的丙型肝炎病毒(HCV)RNA 复制抑制剂。PSI-6130 的 5′-三磷酸酯是 HCV RNA 依赖性 RNA 聚合酶(RdRp)的竞争性抑制剂,并可作为非ligate 链终止器。最近的研究表明,PSI-6130 的新陈代谢也会导致尿苷同系物 β- 的 5′-三磷酸的形成。
d
-2′-deoxy-2′-fluoro-2′-
C
-甲基尿苷(PSI-6206;RO2433)。我们在这里发现,RO2433 的 5′-三磷酸酯(RO2433-TP)的形成需要 PSI-6130 单磷酸酯的脱氨基作用,RO2433 单磷酸酯随后分别被细胞中的 UMP-CMP 激酶和核苷二磷酸激酶磷酸化为相应的二磷酸酯和三磷酸酯。RO2433-TP 是一种强效的 HCV RdRp 抑制剂;然而,酶法和细胞法测定都表明,三磷酸 PSI-6130 是一种比 RO2433-TP 更强效的 HCV RdRp 抑制剂。