Design and Synthesis of HIV Integrase as Potential Anti-AIDS Drugs

HIV-1整合酶（IN）抑制剂代表了最新的抗艾滋病药物。默克公司的raltegravir（2007年10月）和吉利德公司的elvitegravir（2012年8月）是首批获得FDA批准的两种IN抑制剂。这些药物是一类被称为“IN链转移抑制剂”的药物的成员，因为与酶的3'-加工（3'-P）反应相比，它们能够优先阻断酶的链转移（ST）反应。用RAL和EVG治疗选择耐药的艾滋病毒，这两种药物存在相当大的交叉耐药。葛兰素史克（GlaxoSmithKline）的dolutegravir （DTG）于2013年8月获得FDA批准，作为第二代INSTI，对RAL和evg耐药的HIV菌株具有更好的疗效。然而，DTG也选择了耐药的HIV菌株，强调需要继续开发能够克服IN耐药菌株的药物，包括新出现的DTG耐药菌株。利用我实验室的设计和合成能力，我们与药理学家（Yves Pommier博士，NCI）、病毒学家（Hughes博士，NCI）和结构生物学家（Cherepanov博士，伦敦研究所）合作开发新的IN抑制剂。这些努力导致了1-羟基-1,8-萘啶- 2h -1 -3-羧酰胺的发现，它在生化检测中能有效抑制野生型（WT） in，并在HIV-1感染的单轮感染检测中显示出良好的抗病毒效果。重要的是，该系列的成员在后一种检测中对ral耐药突变体保持良好的抗病毒效力。最近，我们发现通过对1-羟基-2-氧- 1,8 -萘啶支架的6位进行修饰，我们能够获得具有低纳摩尔效的inis，以对抗整个病毒组，包括典型的inis抗性IN变体。这些化合物具有较低的细胞毒性，在某些情况下，其选择性指数（CC50/EC50）大于10,000。通过与Cherepanov博士的合作，我们获得了与原型泡沫病毒（PFV）“侵入体”（与底物DNA的四聚体整合酶）结合的先导抑制剂的共晶体结构。该数据阐明了化合物作用的结构基础，并提供了可能对进一步优化生化功效有用的关键见解。HIV-1逆转录酶（RT）的聚合酶（Pol）和RNase H结构域与IN一起属于一个多核苷酸转移酶超家族，它们具有相似的催化机制，涉及两个二价金属离子。我们发现，我们最近的inss成员抑制rt的Pol和RNase H活性。进一步开发针对这些靶点的抑制剂的工作正在进行中。

Inhibitors of HIV-1 integrase (IN) inhibitors represent the most recent anti-AIDS drugs. Merck's raltegravir (RAL) (October 2007) and Gilead's elvitegravir (EVG) (August 2012) were the first two IN inhibitors to be approved by the FDA. These agents are members of a class of drugs called "IN strand transfer inhibitors" (INSTIs), due to their ability to preferentially block the enzyme's strand transfer (ST) reaction as compared to the enzymes 3'-processing (3'-P) reaction. Treatment with RAL and EVG selects for resistant forms of HIV and there is considerable cross-resistance to these two drugs. GlaxoSmithKline's dolutegravir (DTG) was approved by the FDA in August of 2013 as a 2nd-generation INSTI having improved efficacies against RAL and EVG-resistant strains of HIV. However, DTG also selects for resistant strains of HIV, emphasizing the need for continued development of agents that can overcome resistant strains of IN, including the emerging DTG-resistant strains. Utilizing my laboratory's design and synthetic capabilities, we have teamed with pharmacologists (Dr. Yves Pommier, NCI), virologists (Dr. Hughes, NCI) and structural biologists (Dr. Cherepanov, London Research Institute) to develop new IN inhibitors. These efforts have resulted in the discovery of 1-hydroxy-1,8-naphthyridin-2H-one-3-carboxamides, which potently inhibit wild-type (WT) IN in biochemical assays and show good anti-viral efficacies in single-round infection assays of HIV-1 infectivity. Importantly, members of this series retain good anti-viral potency against RAL-resistant mutants in the latter assays. More recently, we have found by introducing modifications to the 6-position of the 1-hydroxy-2-oxo-1, 8-naphthyridine scaffold, that we are able to obtain INSTIs with low nanomolar potencies against an entire panel of viruses, including the canonical INSTI-resistant IN variants. The compounds are characterized by low cytotoxicities, which in several cases, results in selectivity indices (CC50/EC50) of greater than 10,000. In collaboration with Dr. Cherepanov, we have obtained co-crystal structures of our lead inhibitors bound to the prototype foamy virus (PFV) "intasome" (tetrameric integrase with substrate DNA). This data clarifies the structural basis of the compounds' actions and provides key insights that may be useful in further optimizing biochemical efficacies. Along with IN, the HIV-1 polymerase (Pol) and RNase H domains of reverse transcriptate (RT), belong to a superfamily of polynucleotidyl transferases that share a similar catalytic mechanism involving two divalent metal ions. We have found that members of our recent INSTIs inhibit both the Pol and RNase H activities of RT. Work is in progress to further develop inhibitors directed at these targets.