Drug Resistance in HCV NS3/4A - Inhibitor binding versus substrate recognition

描述(申请人提供)：据估计，全球有1.8亿人感染丙型肝炎病毒(HCV)，每年有300-400万人新感染，是美国肝病死亡的主要原因。对于那些意识到他们的丙型肝炎病毒阳性状态的人，治疗包括一年的诊所就诊，治疗方案往往耐受性很差，即使如此，只有大约50%的接受治疗的患者被治愈。针对病毒蛋白的新药NS3/4A正在进行临床试验。NS3/4A是一种双功能蛋白酶/解旋酶。然而，耐药性正在迅速上升，可能会使许多有希望的治疗方法在时代到来之前就过时了。我们正在提出一种新的药物设计策略来避免耐药性，我们已经成功地将其应用于HIV-1蛋白酶，并开发了一种保持对一组耐药病毒的亲和力的个位数PM抑制剂。我们假设这一策略有效并适用于丙型肝炎病毒NS3/4A的蛋白酶域，因为在分子水平上，耐药性是分子识别事件平衡的变化，选择性地削弱抑制物结合，但维持底物识别和切割。为了了解和减少耐药的可能性，需要阐明底物识别的原子细节。因此，在本提案中，我们通过晶体结构、分子动力学模拟和酶动力学的组合来表征NS3/4A的四种不同的天然底物复合体。所得到的结构可能定义底物包膜，该底物包膜定义底物识别所需的区域，并将其与抑制剂的结合和已知的耐药性模式进行比较。然后，可以使用丙型肝炎病毒NS3/4A底物包膜作为设计、合成和评估新型NS3/4A蛋白酶抑制剂的附加约束，这些新的NS3/4A酶抑制剂可能对丙型肝炎病毒的耐药性不那么敏感。) 公共卫生相关性：据估计，全球有1.8亿人感染丙型肝炎病毒(丙型肝炎病毒)，每年有300-400万人新感染，是美国肝病死亡的主要原因。对于那些意识到他们的丙型肝炎病毒阳性状态的人，治疗包括一年的诊所就诊，治疗方案往往耐受性很差，即使如此，只有大约50%的接受治疗的患者被治愈。针对病毒蛋白NS3/4a的新药正在进行临床试验，然而，耐药性正在迅速上升，可能会使许多这些有希望的疗法在时代到来之前就过时了。我们正在提出一种新的药物设计策略，以避免耐药性。)

DESCRIPTION (provided by applicant): An estimated 180 million people are infected with hepatitis C virus (HCV) globally and 3-4 million are newly infected each year and is the leading cause of death from liver disease in the United States. For those aware of their positive HCV status, treatment involves a year of clinic visits with an often poorly tolerated treatment regime and even so only about 50% of treated patients are cured. New drugs targeting the viral protein, NS3/4A, which is a bifunctional protease/helicase are in clinical trials. However, drug resistance is arising quickly, likely rendering many of these promising therapeutics obsolete before their time. We are proposing a new drug design strategy to avoid drug resistance, which we have successfully applied to HIV-1 protease and developed single-digit pM inhibitors that retain affinity against a panel of drug resistant viruses. We hypothesize that this strategy works and is applicable to the protease domain of HCV NS3/4A, since at a molecular level drug resistance is a change in the balance of molecular recognition events that selectively weakens inhibitor binding but maintains substrate recognition and cleavage. To understand and reduce the likelihood of drug resistance, the atomic details of substrate recognition need to be elucidated. Thus in this proposal we are characterizing the four diverse natural substrate complexes of NS3/4A, through a combination of crystal structures, molecular dynamics simulations and enzyme kinetics. The resulting structures will likely define a substrate envelope, which defines the region necessary for substrate recognition and will be compared with the binding of inhibitors and the known patterns of drug resistance. The HCV NS3/4A substrate envelope can then be used as an added constraint in the design, synthesis and assessment of novel NS3/4A protease inhibitors that will likely be less susceptible to HCV drug resistance.) PUBLIC HEALTH RELEVANCE: An estimated 180 million people are infected with hepatitis C virus (HCV) globally and 3-4 million are newly infected each year and is the leading cause of death from liver disease in the United States. For those aware of their positive HCV status, treatment involves a year of clinic visits with an often poorly tolerated treatment regime and even so only about 50% of treated patients are cured. New drugs targeting the viral protein, NS3/4a are in clinical trials, however, drug resistance is arising quickly, likely rendering many of these promising therapeutics obsolete before their time. We are proposing a new drug design strategy to avoid drug resistance. )