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

描述（由申请人提供）：核苷类逆转录酶抑制剂（NRTIs）是临床上使用的最有效的抗逆转录病毒药物之一，通常用于HIV感染的一线治疗。然而，耐药在艾滋病毒药物经验丰富的患者中越来越普遍，迫切需要确定和开发针对这些耐药艾滋病毒株有效的新抗逆转录病毒药物。所有被批准的nrti都作为链终止体，因为它们缺乏3'OH，并且长期以来一直认为缺乏3'OH对抗病毒活性至关重要。然而，这一特征也会给抑制剂带来不利的特性，例如与dNTP底物相比，对RT的亲和力降低，以及细胞内向活性核苷三磷酸的转化减少。我们和我们的合作者已经获得了新的核苷4'-乙基，2-氟脱氧腺苷（4' e - 2fda）的数据，挑战了现有的范式。4'E-2FdA是迄今为止描述的最有效的NRTI，尽管保留了可接近的3'OH，但仍可作为链终止剂。我们的初步数据表明，这种明显的链终止是由于引物3'端在与化合物结合后难以转位。因此，我们认为4'E-2FdA是一种易位缺陷逆转录酶抑制剂（TDRTI）。我们假设3'OH, 4'E和2F基团的存在有助于高效力并导致新的抑制机制。我们建议进行详细的生化研究，以更好地了解这些新型nrti的工作原理，并确定这些化合物的具体特性，这些特性有助于其显著的抗病毒效力和出色的耐药性。为此，我们将追求以下具体目标：确定TDRTIs抑制RT的生化机制。2. rt法确定TDRTI切除的生化机制。测定TDRTIs对临床相关耐nrti RTs的抑制作用；临床相关的RT抑制剂与tdrti的相互作用以及联合用药的毒性。4. 确定HIV对TDRTIs的耐药性机制。实现这些目标将大大促进科学知识的发展，并在设计新一代高度活跃的创新nrti方面发挥不可估量的作用。

DESCRIPTION (provided by applicant): Nucleoside reverse transcriptase inhibitors (NRTIs) are among the most potent antiretrovirals used clinically, and are often used in first-line therapy for HIV infection. However, resistance is increasingly common in HIV drug experienced patients, and there is an urgent need to identify and develop new antiretrovirals active against these resistant HIV strains. All approved NRTIs act as chain terminators because they lack a 3'OH, and it has been a long standing paradigm that the absence of the 3'OH is essential for antiviral activity. However, this feature can also impart detrimental properties to the inhibitor, such as reduced affinity for RT compared to dNTP substrates, as well as reduced intracellular conversion to the active nucleoside triphosphate. We and our collaborators have obtained data with the novel nucleoside 4'-ethynyl, 2-fluoro deoxyadenosine (4'E-2FdA) that challenge this existing paradigm. 4'E-2FdA is the most potent NRTI described to date and acts as a chain terminator despite retaining an accessible 3'OH. Our preliminary data suggest that this apparent chain termination arises from difficulty of the primer 3'-terminus to translocate following incorporation of the compound. We therefore propose that 4'E-2FdA is a Translocation-Deficient Reverse Transcriptase Inhibitor (TDRTI). We hypothesize that the presence of the 3'OH, 4'E and 2F groups contribute to the high potency and result in the novel mechanism of inhibition. We propose to conduct detailed biochemical studies to better understand how these novel NRTIs work and to determine the specific characteristics of these compounds that contribute to their pronounced antiviral potency and excellent resistance profiles. To this end we will pursue the following Specific Aims: 1. Determine the biochemical mechanism of RT inhibition by TDRTIs. 2. Determine the biochemical mechanism of TDRTI excision by RT. 3. Determine inhibition of clinically relevant NRTI-resistant RTs by TDRTIs; interactions of clinically relevant RT inhibitors with TDRTIs and toxicity of combinations. 4. Determine the mechanism of HIV resistance to TDRTIs. Addressing these aims should significantly advance scientific knowledge and be invaluable in the design of new generations of highly active innovative NRTIs. PUBLIC HEALTH RELEVANCE: This project will characterize the biochemical and molecular basis for the unprecedented efficiency of a novel class of compounds that suppress HIV viruses extremely efficiently, and by doing so, it will help develop anti- HIV therapeutics that are both less susceptible to current clinically significant resistance mutations as well as more refractory to the development of viral drug resistance.