Ultrapotent Inhibitors of Wild-type and Multi-drug Resistant HIV

产品说明：核苷类逆转录酶抑制剂（NRTI）是治疗HIV感染患者的高效抗逆转录病毒疗法（HAART）的关键组成部分。所有FDA批准的抗HIV NRTI都缺乏3 '-OH，因此通过直接链终止抑制HIV RT引起的DNA聚合。与天然dNTP底物相比，3 '-OH的不存在也通过降低它们对RT的结合亲和力和减少细胞内转化为活性NRTI三磷酸而赋予这些NRTI有害的性质。 我们已经在第一个资助周期期间报道了4 '-乙炔基-2-氟-2'-脱氧腺苷（EFdA）是保留3 '-OH部分的核苷类似物，并且表现出优异的抗病毒特性（在PBMC中EC 50 = 50 pM）和显著的选择性指数（> 200，000）。EFdA的效力和选择性指数比目前批准的所有抗HIV药物都要好几个数量级。尽管存在3 '-OH，但掺入的EFdA-单磷酸主要作为直接链终止剂，因为RT难以在具有3'-末端EFdA-MP的引物上易位，这是一种独特的作用机制。因此，EFdA-TP是一种易位缺陷型RT抑制剂（TDRTI）。此外，EFdA还显示出有效抑制临床上重要的NRTI耐药HIV毒株，并显示出对替诺福韦耐药K65 R HIV的过敏性。值得注意的是，在我们对SIV感染的猕猴的研究中，用EFdA治疗后抑制病毒载量的动物携带M184 V突变，表明M184 V可以被EFdA有效抑制。我们还表明，EFdA对HIV耐药具有非常高的屏障，许多EFdA耐药HIV毒株的复制能力降低。最近，我们已经表明，EFdA与阿匹韦林的组合显示出协同效应，这将是有用的新的治疗方案的设计。 我们将在第一个资助周期的基础上，了解EFdA在RT和细胞水平的效力，EFdA耐药性的发展，以及EFdA与目前批准的抗HIV药物的组合。我们还将使用生物化学和结构的方法来表征EFdA在RT水平上的抑制机制，通过脱氧胞苷激酶（dCK）和腺苷脱氨酶（ADA）的脱氨基作用来激活EFdA。 这项研究将提供信息，指导设计新型NRTI和EFdA与其他已批准的抗HIV药物的联合治疗，这可能导致HIV感染治疗的突破。

DESCRIPTION: Nucleoside reverse transcriptase inhibitors (NRTIs) are key components of Highly Active Antiretroviral Therapies (HAART) for the treatment of HIV-infected patients. All FDA-approved anti-HIV NRTIs lack a 3'-OH, and therefore inhibit DNA polymerization by HIV RT through immediate chain termination. The absence of a 3'-OH also imparts detrimental properties to these NRTIs by reducing their binding affinity for RT compared to the natural dNTP substrates and reducing intracellular conversion to active NRTI triphosphates. We have reported during the first funding cycle that 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a nucleoside analog that retains the 3'-OH moiety and demonstrates exceptional antiviral properties (EC50 = 50 pM in PBMCs) and a remarkable selectivity index (>200,000). EFdA's potency and selectivity index is by orders of magnitude more favorable than all currently-approved anti-HIV drugs. Despite the presence of a 3'-OH, the incorporated EFdA-monophosphate acts primarily as an immediate chain terminator because RT has difficulty translocating on the primer possessing 3'-terminal EFdA-MP, which is a unique mechanism of action. Therefore, EFdA-TP is a Translocation-Defective RT inhibitor (TDRTI). Additionally, EFdA has also been shown to efficiently inhibit clinically-important NRTI-resistant HIV strains, and demonstrating hypersusceptibility to the tenofovir-resistant K65R HIV. Notably, in our study of SIV-infected macaques the animals that had suppressed viral loads upon treatment with EFdA carried the M184V mutation, suggesting that M184V can be effectively suppressed by EFdA. We have also shown that EFdA has a remarkably high barrier for HIV resistance, and many EFdA-resistant HIV strains have reduced replication capacity. More recently we have shown that the combination of EFdA with Rilpivirine shows a synergistic effect, which would be useful in the design of new therapeutic regimens. We will build on our work from the first funding cycle to understand the potency of EFdA at the RT and cellular levels, development of EFdA resistance, and EFdA combinations with currently-approved anti-HIV drugs. We will also use biochemical and structural approaches to characterize the inhibition mechanism of EFdA at the RT level, the activation of EFdA by deoxycytidine kinase (dCK) and deamination by adenosine deaminase (ADA). This study will provide information that will guide the design of novel NRTIs and EFdA combination therapies with other approved anti-HIV drugs that may lead to a breakthrough in the treatment of HIV infection.