Selected Replicon Variants with Low-Level In Vitro Resistance to the Hepatitis C Virus NS5B Polymerase Inhibitor PSI-6130 Lack Cross-Resistance with R1479
Selected Replicon Variants with Low-Level In Vitro Resistance to the Hepatitis C Virus NS5B Polymerase Inhibitor PSI-6130 Lack Cross-Resistance with R1479
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DOI：
10.1128/aac.00444-08
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发表时间：
2008-12-01
影响因子：
4.9
通讯作者：
Jiang, Wen-Rong
中科院分区：
文献类型：
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作者：
Ali, Samir;Leveque, Vincent;Jiang, Wen-Rong
PSI6130NS5B聚合酶是丙型肝炎病毒((beta-D-2‘-deoxy-2’-fluoro-2‘-C-methylcytidine)is)复制的选择性抑制物。PSI-6130的前体药物R7128已在慢性感染丙型肝炎病毒1a(GT-1a)和GT-1b的患者中显示出抗病毒效果。我们观察到，该化合物在体外对实验室优化的丙型肝炎病毒复制子以及一组含有来自GT-1a和GT-1b临床分离株的NS5B丙型肝炎病毒聚合酶的复制子显示出很强的活性。我们使用丙型肝炎病毒复制子细胞系统来检查对PSI-6130敏感性降低的变异体的出现。用PSI-6130短期处理含有丙型肝炎病毒亚基因组复制子的细胞可以清除复制子，而不会产生抗药性变异。在化合物选择下对细胞的长期培养产生了S282T替换，与NS5B聚合酶中的其他氨基酸替换形成了复杂的模式。共选替换的存在并没有增加由S282T替换导致的对PSI-6130的中等程度的三到六倍的敏感性损失；然而，与单独使用S282T替换相比，它们的存在增强了复制能力。我们还观察到PSI-6130和R1479之间缺乏交叉耐药性，并证明在含有R1479抗性突变的复制子细胞(S96T/N142T)中，PSI-6130长期培养选择会导致S282T替换的出现，并使S96T恢复为野生型丝氨酸。总之，PSI-6130在体外对耐药性选择具有很高的屏障，只选择表现出低水平耐药性的变异体，并且与R1479缺乏交叉耐药性，支持前药R7128作为治疗丙型肝炎病毒感染的治疗剂的继续发展。
PSI-6130 (beta-D-2'-deoxy-2'-fluoro-2'-C-methylcytidine)is a selective inhibitor of hepatitis C virus (HCV) replication that targets the NS5B polymerase. R7128, the prodrug of PSI-6130, has shown antiviral efficacy in patients chronically infected with HCV genotype 1a (GT-1a) and GT-1b. We observed that the compound exhibited potent in vitro activity against laboratory-optimized HCV replicons as well as against a panel of replicons containing NS5B HCV polymerases derived from GT-1a and GT-1b clinical isolates. We used the HCV replicon cell system to examine the emergence of variants with reduced sensitivity to PSI-6130. Shortterm treatment of cells harboring the HCV subgenomic replicon with PSI-6130 cleared the replicon without generating resistant variants. Long-term culture of the cells under the compound selection generated the S282T substitution in a complex pattern with other amino acid substitutions in the NS5B polymerase. The presence of the coselected substitutions did not increase the moderate three-to sixfold loss of sensitivity to PSI-6130 mediated by the S282T substitution; however, their presence enhanced the replication capacity compared to the replication levels seen with the S282T substitution alone. We also observed a lack of cross-resistance between PSI-6130 and R1479 and demonstrated that long-term culture selection with PSI-6130 in replicon cells harboring preexisting mutations resistant to R1479 (S96T/N142T) results in the emergence of the S282T substitution and the reversion of S96T to wild-type serine. In conclusion, PSI-6130 presents a high barrier to resistance selection in vitro, selects for variants exhibiting only low-level resistance, and lacks cross-resistance with R1479, supporting the continued development of the prodrug R7128 as a therapeutic agent for the treatment of HCV infection.