Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium.
Antimicrob Agents Chemother. 2011 Sep;55(9):4103-13. doi: 10.1128/AAC.00294-11. Epub 2011 Jun 27.
Hepatitis C virus (HCV) inhibitors include direct-acting antivirals (DAAs) such as NS3 serine protease inhibitors, nucleoside and nonnucleoside polymerase inhibitors, and host-targeting antivirals (HTAs) such as cyclophilin inhibitors that have been developed in recent years. Drug-resistant HCV variants have been reported both in vitro and in the clinical setting for most classes of drugs. We report a comparative study in which the genetic barrier to drug resistance of a representative selection of these inhibitors is evaluated employing a number of resistance selection protocols. The NS3 protease inhibitors VX-950 and BILN 2061, the nucleoside polymerase inhibitor 2'-C-methylcytidine, three nonnucleoside polymerase inhibitors (thiophene carboxylic acid, benzimidazole, and benzothiadiazine), and DEB025 were included. For each drug and passage in the selection process, the phenotype and genotype of the drug-resistant replicon were determined. For a number of molecules (BILN 2061 and nonnucleoside inhibitors), drug-resistant variants were readily selected when wild-type replicon-containing cells were directly cultured in the presence of high concentrations of the inhibitor. Resistance to DEB025 could be selected only following a lengthy stepwise selection procedure. For some DAAs, the signature mutations that emerged under inhibitor pressure differed depending on the selection protocol that was employed. Replication fitness of resistant mutants revealed that the C445F mutation in the RNA-dependent RNA polymerase can restore loss of fitness caused by a number of unfit resistance mutations. These data provide important insights into the various pathways leading to drug resistance and allow a direct comparison of the genetic barriers of various HCV drugs.
丙型肝炎病毒 (HCV) 抑制剂包括直接作用抗病毒药物 (DAAs)，如 NS3 丝氨酸蛋白酶抑制剂、核苷和非核苷聚合酶抑制剂，以及近年来开发的宿主靶向抗病毒药物 (HTAs)，如亲环素抑制剂。大多数类别的药物在体外和临床环境中都报道了耐药 HCV 变异体。我们报告了一项比较研究，该研究评估了代表这些抑制剂的药物耐药性的遗传屏障，采用了多种耐药选择方案。该研究包括 NS3 蛋白酶抑制剂 VX-950 和 BILN 2061、核苷聚合酶抑制剂 2'-C-甲基胞苷、三种非核苷聚合酶抑制剂（噻吩羧酸、苯并咪唑和苯并噻二嗪）和 DEB025。对于每种药物和选择过程中的每个传代，都确定了耐药复制子的表型和基因型。对于许多分子（BILN 2061 和非核苷抑制剂），当含有野生型复制子的细胞在高浓度抑制剂存在下直接培养时，很容易选择耐药变体。只有在经过漫长的逐步选择过程后，才能选择对 DEB025 的耐药性。对于一些 DAA，在抑制剂压力下出现的特征性突变取决于所采用的选择方案。耐药突变体的复制适应性表明，RNA 依赖性 RNA 聚合酶中的 C445F 突变可以恢复由许多不适应的耐药突变引起的适应性丧失。这些数据为导致耐药性的各种途径提供了重要的见解，并允许直接比较各种 HCV 药物的遗传屏障。
