McGill University AIDS Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada.
J Antimicrob Chemother. 2010 Nov;65(11):2291-9. doi: 10.1093/jac/dkq338. Epub 2010 Sep 18.
We wished to study the resistance profile of etravirine, a novel non-nucleoside reverse transcriptase inhibitor (NNRTI) active against common human immunodeficiency virus type-1 (HIV-1) drug-resistant strains.
We compared the effects of K103N, the most prevalent NNRTI resistance mutation, and M230L on enzyme function, virus replication and extent of biochemical inhibition by etravirine, efavirenz and nevirapine.
Growth kinetics analyses in cord blood mononuclear cells (CBMCs) demonstrated that K103N-containing virus replicated as well as wild-type (WT) virus and that the M230L-containing virus was severely impaired in replication ability in the absence of NNRTIs. K103N-containing viruses replicated well in the presence of efavirenz and nevirapine, while virus containing M230L displayed substantial replication in the presence of all NNRTIs tested. RNA-dependent DNA polymerase assays using a heterogeneous HIV-1 RNA template and purified recombinant WT or mutated reverse transcriptase enzymes revealed that the fold change (FC) for etravirine was 0.7 for K103N and 8 for M230L. K103N and M230L conferred high-level resistance to both efavirenz (FC=39 and 15.3, respectively) and nevirapine (FC=43.5 and 33), confirming that M230L confers cross-resistance to both drugs while K103N-containing viruses remain susceptible to etravirine. In enzymatic assays, the K103N mutation was associated with moderate reductions in the efficiency of 3' DNA end-directed RNA template cleavage, while comparable efficiency to WT enzyme was observed with regard to minus-strand strong stop DNA synthesis and polymerase processivity.
These properties help to explain differences in the evolution and prevalence of these two NNRTI mutations.
我们旨在研究依曲韦林（一种新型非核苷类逆转录酶抑制剂，NNRTI）对常见人类免疫缺陷病毒 1 型（HIV-1）耐药株的耐药谱。
我们比较了 K103N（最常见的 NNRTI 耐药突变）和 M230L 对依曲韦林、依非韦伦和奈韦拉平的酶功能、病毒复制和生化抑制程度的影响。
在脐血单核细胞（CBMC）中的生长动力学分析表明，含有 K103N 的病毒与野生型（WT）病毒一样复制良好，而在没有 NNRTIs 的情况下，含有 M230L 的病毒复制能力严重受损。含有 K103N 的病毒在依非韦伦和奈韦拉平存在的情况下复制良好，而含有 M230L 的病毒在所有测试的 NNRTIs 存在的情况下都显示出大量复制。使用异质 HIV-1 RNA 模板和纯化的重组 WT 或突变逆转录酶酶的 RNA 依赖性 DNA 聚合酶测定表明，依曲韦林的折叠变化（FC）为 K103N 的 0.7 和 M230L 的 8。K103N 和 M230L 对依非韦伦（FC=39 和 15.3，分别）和奈韦拉平（FC=43.5 和 33）均具有高度耐药性，证实 M230L 对两种药物均具有交叉耐药性，而 K103N 病毒仍对依曲韦林敏感。在酶测定中，K103N 突变与 3'DNA 末端导向 RNA 模板切割的效率降低中度相关，而相对于 WT 酶，负链强终止 DNA 合成和聚合酶连续性的效率相当。
这些特性有助于解释这两种 NNRTI 突变的进化和流行程度的差异。
