Inhibitors of HIV-induced downregulation of HLA class I

描述(由申请人提供)：HIV诱导的人类白细胞抗原I类下调的抑制剂多项研究表明，人类白细胞抗原I类(MHC-I)的下调在艾滋病毒感染中起重要作用。病毒蛋白Nef诱导MHC-I下调并干扰病毒抗原的呈递，使艾滋病毒感染细胞对CD8阳性CTL的杀伤不那么敏感。感染SIV的猕猴在这一活动中缺乏迅速恢复能力 消灭MHC-I。然而，Nef下调MHC-I的机制已经得到了广泛的研究，尽管它在发病机制中发挥了重要作用，但这种活性仍然是抗病毒开发的靶点。在许多疱疹病毒、痘病毒、乳头瘤病毒和腺病毒中也发现了对抗原提呈的干扰，进一步强调了这一功能在免疫逃避中的重要性。我们建议筛选一个小分子文库来识别HIV诱导的MHC-I下调的抑制剂。一个高含量的筛选已经得到了充分的优化，来自3440个小分子的试验性试验的初步结果验证了该分析，并确定了阻止这一有希望的目标的小分子。我们的结果证明了概念证明，MHC-I对小分子的有效和特定的下调干扰是可能的。我们提出了以下目标：(1)筛选由高度多样化的结构组成的46,280个类药物分子的文库，包括被选来靶向激酶的分子，以及其他已知具有药理活性的化合物(LOPAC文库)；(2)验证和表征HTS的效力、特异性和毒性；以及(3)鉴定能够增强CTL杀伤HIV感染细胞能力的化合物。我们将使用带有多个内置控件的多模式HTS检测来同时确认主屏幕上的命中，并消除毒性较差的假阳性，以及通过已知机制阻止HIV感染的其他命中。这一第一阶段应用的成功将被定义为鉴定一种或多种真正的先导系列类药物化合物，其EC50低于5？M，细胞毒性最小(CC50至少是EC50的30倍)，以及使艾滋病毒感染细胞对CTL杀伤敏感的能力。在第二阶段的提案中，将从这一筛选中选择化学引线用于药物化学SAR的有效性、特异性和口服生物利用度的优化。我们将进一步研究其作用机制，鉴定耐药菌株， 作为已批准的抗逆转录病毒药物的潜在拮抗剂，并评估与其他药物的交叉耐药性。此外，一些选定的化合物将在HIV感染的小动物模型中进行测试，该模型概括了病毒特异性的CTL反应。具有改进的轮廓和明确的作用机制的化合物将被推进到临床前开发研究中，以支持未来的人体试验。服用抑制MHC-I下调的抗病毒药物可能会延长开始HAART治疗之前所需的时间，或者与其他药物结合使用，可能会通过改善患者对病毒的免疫反应来增强其抗病毒效果。这些研究将构成一个药物发现计划的基础，该计划可能导致一种新的抗病毒药物家族的一流药物，该药物有可能对其他病毒具有更广泛的活性。PHS 398/2590(06/09版)页面续格式页面 与公共卫生有关：截至2010年底，全世界估计有3400万人感染艾滋病毒，全世界每年有180多万人死亡(艾滋病规划署估计)。在美国，每年有18,000名艾滋病患者死亡，约有120万人感染，这一数字正在以每年56,000名新感染者的速度稳步增长(CDC估计)。尽管抗逆转录病毒疗法取得了重要进展，有30多种药物可作为单一药物或联合药物使用，但副作用和出现或具有多药耐药性的病毒仍然对艾滋病毒的治疗构成重大挑战。我们建议通过一种新的机制来鉴定和表征能够阻断HIV的抗逆转录病毒化合物。这些独特的化合物可以用于治疗艾滋病毒感染。。PHS 398/2590(06/09版)页面续格式页面

DESCRIPTION (provided by applicant): Inhibitors of HIV-induced downregulation of HLA class I Multiple studies suggest that downmodulation of HLA class I (MHC-I) plays an important role in HIV infection. The viral protein Nef induces MHC-I downmodulation and interferes with the presentation of viral antigens, making HIV-infected cells less sensitive to killing by CD8-positive CTLs. Macaques infected with SIV deficient in this activity rapidly restore the ability to eliminate MHC-I. The mechanism by which Nef downmodulates MHC-I has been extensively investigated, however, despite its important role in pathogenesis this activity remains to be targeted for antiviral development. Further highlighting the importance of this function in immune evasion, interference with antigen presentation has also been recognized in many herpesviruses, poxviruses, papillomaviruses and adenoviruses. We propose screening a library of small molecules to identify inhibitors of the HIV-induced MHC-I downmodulation. A high content screen has been fully optimized and preliminary findings from a test pilot of 3,440 small-molecules have validated the assay and identified small-molecules blocking this promising target. Our results demonstrate proof-of-concept that potent and specific interference of MHC-I downmodulation with small molecules is possible. We propose the following aims: (1) to screen a library of 46,280 drug-like molecules composed of highly diverse structures, including molecules selected to target kinases, and other compounds known to be pharmacologically active (Lopac library); (2) to validate and characterize the potency, specificity and toxicity of hts, and; (3) to identify compounds that enhance the ability of CTLs to kill HIV- infected cells. We wil use a multi-modal HTS assay with multiple built-in controls to simultaneously confirm hits in primary screens and eliminate false positives with poor toxicity profiles, and other hits blocking HIV infection by known mechanisms. Success in this Phase I application will be defined by identifying one or more bona fide lead series of drug-like compounds with EC50s below 5¿M, minimal cytotoxicity (CC50 at least 30-fold greater than EC50), and the ability to sensitize HIV-infected cells to CTL killing. In a Phase II proposal, chemical leads from this screen will be selected for medicinal chemistry SAR optimization for potency, specificity and oral bioavailability. We wil further study the mechanism of action, characterize drug-resistant strains, ases the potential for antagonism with approved antiretrovirals, and evaluate cross-resistance with other drugs. Additionally, a selected number of compounds will be tested in a small-animal model of HIV infection that recapitulates the virus-specific CTL responses. Compounds with improved profiles and characterized mechanism of action will be advanced into preclinical development studies to support future human trials. Administration of antivirals inhibiting MHC-I downmodulation may lengthen the time required before initiation of HAART therapy, or alternatively, in combination with other drugs may enhance their antiviral effect by improving the patient's immune response against the virus. These studies will constitute the foundation of a drug discovery program that may lead to first-in-class drugs of a novel family of antivirals with the potential for broader activity against other viruses. PHS 398/2590 (Rev. 06/09) Page Continuation Format Page PUBLIC HEALTH RELEVANCE: As of the end of 2010, 34 million people worldwide are estimated to be infected with HIV, and more than 1.8 million deaths occur annually worldwide (UNAIDS estimates). 18,000 persons with AIDS die each year in the United States, approximately 1.2 million people are infected, and this number is steadily growing at a rate of 56,000 new infections every year (CDC estimates). Despite important advances in ARV therapies and more than 30 medications available as single drugs or combinations, side-effects and the emergence or multi-drug resistant viruses still pose important challenges for the treatment of HIV. We propose to identify and characterize antiretroviral compounds that block HIV through a novel mechanism. These unique compounds could be used for the treatment of HIV infection. . PHS 398/2590 (Rev. 06/09) Page Continuation Format Page