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

描述（由申请人提供）：核苷逆转录酶抑制剂（NRTI）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，耐药性在HIV药物经验丰富的患者中越来越普遍，迫切需要鉴定和开发针对这些耐药HIV菌株的新的抗逆转录病毒药物。所有批准的NRTI都作为链终止剂，因为它们缺乏3 'OH，并且长期以来的范例是，3' OH的缺乏对于抗病毒活性是必不可少的。然而，该特征也可以赋予抑制剂有害的性质，例如与dNTP底物相比降低的对RT的亲和力，以及降低的向活性核苷三磷酸的细胞内转化。我们和我们的合作者已经获得了新核苷4 '-乙炔基，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，并且尽管保留了可接近的3' OH，但仍充当链终止剂。我们的初步数据表明，这种明显的链终止是由于引物3 '-末端在化合物掺入后难以易位引起的。因此，我们认为4 'E-2FdA是一种易位缺陷型逆转录酶抑制剂（TDRTI）。我们推测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物化学研究，以更好地了解这些新型NRTI如何工作，并确定这些化合物的具体特征，这些特征有助于其显著的抗病毒效力和优异的耐药性。为此，我们将追求以下具体目标：1。确定TDRTIs抑制RT的生化机制。2. RT-PCR检测TDRTI切除的生化机制。确定TDRTI对临床相关NRTI耐药RT的抑制作用;临床相关RT抑制剂与TDRTI的相互作用以及联合用药的毒性。4.确定艾滋病毒对TDRTIs耐药的机制。实现这些目标将大大推进科学知识，并在设计新一代高度活跃的创新NRTI方面具有宝贵价值。 公共卫生相关性：该项目将描述一种新型化合物的前所未有的效率的生物化学和分子基础，这种化合物非常有效地抑制HIV病毒，通过这样做，它将有助于开发抗HIV治疗剂，这些治疗剂对目前临床上显著的耐药突变不敏感，并且对病毒耐药性的发展更难治疗。

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.