Rational Design of NRTI for Drug Resistant HIV-1

描述（由申请人提供）：核苷类似物逆转录酶抑制剂（NRTI）是治疗HIV-1感染不可或缺的组成部分。目前批准的NRTI有明显的局限性，包括短期和长期毒性，与其他抗逆转录病毒药物的药代动力学相互作用，以及与其他NRTI交叉耐药的耐药HIV-1变体的选择。因此，迫切需要开发新的NRTI，这些NRTI具有良好的活性和安全性，并且与现有药物很少或没有交叉抗性。我们假设，基于对耐药机制和影响耐药机制敏感性的NRTI结构成分的了解，合理设计NRTI代表了识别抗耐药HIV-1的新NRTI的最佳策略。利用这种结构-活性-耐药性研究的数据，我们已经确定了一类先导化合物，3'-叠氮-2',3'-二脱氧嘌呤（ADPs），它们对许多HIV-1耐药变体具有有效的活性。这些包括耐药变异(i)提高HIV-1逆转录酶区分天然dNTP底物和nrti -三磷酸的能力，以及（ii）增强从过早终止的DNA链上切除终止链的nrti -单磷酸的能力。在本申请中，我们建议深入研究结构-活性-抗性关系，细胞内药理学，毒性和抗性选择，以确定ADP类中最有前途的临床候选药物。这将通过三个具体目标来实现。在Aim 1中，我们将合成额外的新型ADP类似物及其前药，以优化对野生型和nrti耐药HIV-1的效力。在Aim 2中，显示出良好的抗hiv -1活性和交叉抗性谱的ADPs将通过测试其对人类线粒体和骨髓祖细胞的潜在毒性进一步表征。在目标3中，我们将选择并表征对ADPs具有抗性的HIV-1变异，并阐明抗性产生的分子机制。通过本研究提出的合理设计和评估来鉴定和开发新的ADPs，可以帮助满足对有效和安全的抗耐药HIV-1的NRTI不断扩大的需求。

DESCRIPTION (provided by applicant): Nucleoside analog reverse transcriptase inhibitors (NRTI) are integral components of therapy for HIV-1 infection. The currently approved NRTI have significant limitations that include short- and long-term toxicity, pharmacokinetic interactions with other antiretroviral drugs, and the selection of drug-resistant HIV-1 variants that are cross-resistant with other NRTI. Accordingly, there is a critical need to develop new NRTI that have excellent activity and safety profiles and exhibit little or no cross-resistance with existing drugs. We hypothesize that the rational design of NRTI, based on knowledge of both resistance mechanisms and structural components of NRTI that affect sensitivity to these resistance mechanisms, represents the best strategy to identify new NRTI that are active against drug resistant HIV-1. Using data derived from such structure-activity-resistance studies, we have identified a lead class of compounds, the 3'-azido-2',3'- dideoxypurines (ADPs), that retain potent activity against many drug-resistant variants of HIV-1. These include drug-resistant variants that (i) improve the ability of HIV-1 reverse transcriptase to discriminate between the natural dNTP substrate and the NRTI-triphosphate, and (ii) enhance the excision of the chain- terminating NRTI-monophosphate from the prematurely terminated DNA chain. In this application, we propose in-depth studies of structure-activity-resistance relationships, intracellular pharmacology, toxicity, and resistance selection to identify the most promising clinical candidates from the ADP class. This will be accomplished through three Specific Aims. In Aim 1, we will synthesize additional, novel ADP analogs, and prodrugs thereof, to optimize potency against both wild-type and NRTI-resistant HIV-1. In Aim 2, the ADPs that demonstrate favorable anti-HIV-1 activity and cross-resistance profiles will be further characterized by testing their potential toxicity toward human mitochondria and bone marrow progenitor cells. In Aim 3, we will select and characterize HIV-1 variants that are resistant to the ADPs, and elucidate the molecular mechanism(s) by which resistance is conferred. The identification and development of the novel ADPs through the rational design and assessments proposed in this application could help meet the expanding need for potent and safe NRTI that are active against drug-resistant HIV-1.