A novel substrate-based HIV-1 protease inhibitor drug resistance mechanism
A novel substrate-based HIV-1 protease inhibitor drug resistance mechanism
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DOI：
10.1371/journal.pmed.0040036
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发表时间：
2007-01-01
期刊：
影响因子：
15.8
通讯作者：
Boucher, Charles A. B.
中科院分区：
文献类型：
--
作者：
Nijhuis, Monique;van Maarseveen, Noortje M.;Boucher, Charles A. B.
背景 HIV 蛋白酶抑制剂 (PI) 治疗可快速选择病毒蛋白酶中含有一处或两处取代的耐药病毒变体。为了对抗 PI 抗性的发展，已经开发了两种方法。第一个是提高患者血浆中 PI 的水平，第二个是开发新型 PI，对已知的 PI 抗性 HIV 蛋白酶变体具有高效力。这两种方法都需要大量增加蛋白酶突变数量才能导致临床耐药性，从而增加遗传屏障。我们研究了 HIV 是否可以再次找到一种方法来降低对这些新型抑制剂的敏感性。方法和发现我们使用具有增加的遗传屏障的新型 PI (RO033-4649) 进行了体外选择实验，并证明与野生型相比，三种病毒对所有 PI 的耐药性高出 4 至 8 倍。这些PI抗性病毒在病毒蛋白酶中没有单一取代。全基因组测序揭示了所有三种耐药病毒的病毒 Gag 多蛋白（K436E 和/或 I437T/V）中存在 NC/p1 切割位点替换。当这些变化引入参考菌株时，会赋予 PI 抗性。导致 PI 抗性的机制是野生型蛋白酶对改变的底物的处理效率的提高。对 28,000 个临床分离株的基因型和表型耐药性谱的分析表明，一些临床样本中存在这些 NC/p1 切割位点突变（密码子 431 替换占 13%，密码子 436 替换占 8%，密码子 437 替换占 10%）。此外，这些切割位点替换与缺乏初级蛋白酶突变的临床分离株对 PI 敏感性降低高度显着相关。此外，我们使用临床试验（NARVAL，ANRS 088）的数据来证明这些 NC/p1 切割位点的变化与 PI 治疗期间的病毒学失败相关。结论 HIV 可以使用替代机制通过改变底物而不是蛋白酶来对 PI 产生耐药性。需要进一步的研究来确定裂解位点突变在多大程度上可以解释 PI 治疗期间的病毒学失败。
Background HIV protease inhibitor (PI) therapy results in the rapid selection of drug resistant viral variants harbouring one or two substitutions in the viral protease. To combat PI resistance development, two approaches have been developed. The first is to increase the level of PI in the plasma of the patient, and the second is to develop novel PI with high potency against the known PI-resistant HIV protease variants. Both approaches share the requirement for a considerable increase in the number of protease mutations to lead to clinical resistance, thereby increasing the genetic barrier. We investigated whether HIV could yet again find a way to become less susceptible to these novel inhibitors.Methods and Findings We have performed in vitro selection experiments using a novel PI with an increased genetic barrier (RO033-4649) and demonstrated selection of three viruses 4- to 8-fold resistant to all PI compared to wild type. These PI- resistant viruses did not have a single substitution in the viral protease. Full genomic sequencing revealed the presence of NC/p1 cleavage site substitutions in the viral Gag polyprotein (K436E and/or I437T/V) in all three resistant viruses. These changes, when introduced in a reference strain, conferred PI resistance. The mechanism leading to PI resistance is enhancement of the processing efficiency of the altered substrate by wild-type protease. Analysis of genotypic and phenotypic resistance profiles of 28,000 clinical isolates demonstrated the presence of these NC/p1 cleavage site mutations in some clinical samples (codon 431 substitutions in 13%, codon 436 substitutions in 8%, and codon 437 substitutions in 10%). Moreover, these cleavage site substitutions were highly significantly associated with reduced susceptibility to PI in clinical isolates lacking primary protease mutations. Furthermore, we used data from a clinical trial (NARVAL, ANRS 088) to demonstrate that these NC/p1 cleavage site changes are associated with virological failure during PI therapy.Conclusions HIV can use an alternative mechanism to become resistant to PI by changing the substrate instead of the protease. Further studies are required to determine to what extent cleavage site mutations may explain virological failure during PI therapy.