Development of novel small-molecule inhibitors of HIV-1 fusion as microbicides

描述（由申请人提供）：来自替诺福韦凝胶CAPRISA 004试验的阳性数据激发了人们对开发HIV-1进入抑制剂作为局部杀微生物剂或甚至系统性递送预防药物以预防HIV-1性传播的极大兴趣。虽然已经进行了相当大的努力来发现和开发通过靶向gp 41亚基来抑制HIV-1包膜糖蛋白（Env）介导的病毒-细胞融合的小分子药剂，但是这些化合物中没有一种在局部杀微生物剂的临床开发中成功地推进。本研究计划的长期目标是开发一种安全高效的低分子量gp 41融合抑制剂，用作抗HIV-1杀微生物剂的活性成分。在初步工作中，我们已经确定了HIV-1融合抑制剂苯基磺酰胺衍生物（PSD）的新靶点，这是首次在Env介导的细胞-细胞融合抑制剂筛选中确定的。该化合物与gp 41亚结构域内的保守疏水口袋结合。我们证明，新的PSD类似物有效地抑制体外感染的人T细胞的主要HIV-1分离株与不同的地理来源和共受体的要求。我们已经定义了一个临时的结构活性关系（SAR）的PSD。结构数据和SAR表明PSD修饰可以改善效力和药理学性质。我们建议利用初步工作中开发的结构数据，SAR和合成程序来设计，合成和评估新的PSD类似物，这些类似物对广谱性传播药物敏感和耐药HIV-1菌株具有增强的功效。为了实现我们的目标，我们制定了以下具体目标：1.利用gp 41融合蛋白-靶点相互作用的结构原理优化PSD的抗病毒效力和杀微生物特性。2.评价新型PSD的效力、广度和协同相互作用、抗病毒活性和耐药性的分子基础、理化性质以及体外和体内毒性。3.评价新型PSD在体外和体内粘膜保护抗HIV-1感染的有效性。这些目标的动机是有机会验证新的gp 41疏水口袋作为抑制剂结合的目标，基于我们对特定的通道-靶位点相互作用的鉴定，这些相互作用是基于结构的HIV-1 gp 41进入细胞功能拮抗作用的基础，并且可以加强以提高效力和广谱活性。我们的能力，拼凑在一起的定量图片，这些走廊的目标相互作用设置stge为合理开发新的小分子gp 41融合抑制剂的预防和/或治疗干预的HIV-1感染。

DESCRIPTION (provided by applicant): Positive data from the CAPRISA 004 trial of tenofovir gel have stimulated tremendous interest in development of HIV-1 entry inhibitors as topical microbicides or even systematically delivered prophylactic drugs to prevent the sexual transmission of HIV-1. While considerable effort has gone into discovering and developing small-molecule agents that inhibit HIV-1 envelope glycoprotein (Env)-mediated virus-cell fusion by targeting the gp41 subunit, none of these compounds has successfully advanced in clinical development of topical microbicides. The long-term objective of this research plan is to develop a safe and highly effective low-molecular-weight gp41 fusion inhibitor for use as an active ingredient in anti-HIV-1 microbicides. In preliminary work, we have identified the novel target of the HIV-1 fusion inhibitor phenyl sulfonamide derivative (PSD) that was first identified in an Env-mediated cell-cell fusion inhibitor screen. This compound binds to a conserved hydrophobic pocket within a subdomain of gp41. We demonstrate that new PSD analogs potently inhibit in vitro infection of human T cells by primary HIV-1 isolates with different geographic origins and co-receptor requirements. We have defined a provisional structure-activity relationship (SAR) for PSDs. The structural data and SAR suggest PSD modifications that could improve potency and pharmacological properties. We propose to leverage the structural data, SAR and synthetic procedures developed in preliminary work to design, synthesize and evaluate novel PSD analogs that have enhanced efficacy against a broad-spectrum of sexually transmitted drug-sensitive and drug-resistant HIV-1 strains. To achieve our goals we have developed the following specific aims: 1. To utilize the structural principles of gp41 fusion inhibitor-target interactions to optimize the antiviral potency and microbicidal properties of PSDs. 2. To evaluate the potency, breadth and synergistic interactions, the molecular basis for antiviral activity and resistance, the physicochemical properties and the in vitro and in vivo toxicity of novel PSDs. 3. To evaluate the effectiveness of novel PSDs in mucosal protection against HIV-1 infection in vitro and in vivo. These aims are motivated by the opportunity to validate the novel gp41 hydrophobic pocket as the target of inhibitor binding, based on our identification of specific inhibitor-target site interactions that underlie structure-based antagonism of HIV-1 gp41 function in cell entry and that can be strengthened to improve potency and broad-spectrum activity. Our ability to piece together a quantitative picture of these inhibitor-target interactions sets the stge for rational development of new small-molecule gp41 fusion inhibitors for prophylactic and/or therapeutic intervention of HIV-1 infection.