Inhibitors of Anthrax Lethal Factor Metalloproteinase

描述（由申请人提供）：炭疽致死因子（LF）是一种金属蛋白酶，在被炭疽芽孢杆菌感染时被引入哺乳动物宿主细胞。LF破坏由MAPKKs介导的细胞内信号通路，导致细胞毒性、败血症、呼吸衰竭和快速死亡。如果在症状出现后的最初48小时内给予抗生素治疗是有效的，但如果在这个狭窄的治疗窗口之后才开始使用抗生素治疗，则无法预防死亡。虽然接触这种病原体在自然界是有限的，但炭疽芽孢作为一种生物恐怖主义武器的致命性在2001年通过美国邮件进行的袭击中得到了证明。需要能够抑制LF毒性作用的新疗法来对抗晚期疾病。目前的治疗方法，如抗生素、疫苗和正在开发的生物疗法，都存在明显的缺陷。它们的共同点是无法保护细胞免受LF的直接影响。这些疗法也容易受到下一代利用LF毒性的转基因武器的攻击。直接靶向LF活性可能与目前的治疗方法产生协同作用，并且是唯一提出的可以在晚期感染期间提供拯救的炭疽治疗方法。使用LF抑制剂作为一种治疗方法最近已在动物中得到验证。然而，到目前为止，还没有报道过LF抑制剂具有在大规模生物恐怖主义炭疽袭击事件中保护普通人群的药物所需的特性。夏威夷生物技术公司（HBI）目前的策略采用三级筛选级联试验，旨在鉴定在炭疽感染动物模型中具有良好PK特性和疗效的强效LF抑制剂。要实现这一目标，需要对HBI中发现的抑制剂进行持续的药物化学优化，并确定新的先导系列。HBI专门针对LF开发的计算高通量对接协议将用于发现新的抑制剂，作为现有线索的备份。体外分析化合物以评估LF的效价和选择性，以及铅系列的分子模型将指导效价优化。在HBI制备的一组独特的LF突变体也将用于指导新型LF抑制剂的设计和优化。将确定强效抑制剂的物理化学性质、PK和ADMET特性，以便选择最佳的候选药物进行体内试验。最后，潜在的临床前候选药物的功效将在已建立的炭疽感染动物模型中得到证明。II期续期中提出的工作将建立在HBI将LF作为药物靶点的专业知识的基础上，目标是确定一种口服生物可用的临床前候选药物，该候选药物在暴露后炭疽致死因子中毒的动物模型中显示出体内疗效。2001年的生物恐怖袭击，通过美国邮政传递炭疽孢子，导致11例确诊病例，并导致5人死亡。目前缺乏针对炭疽接触的有效治疗方法，使这一不幸的悲剧真正有可能重演。这项研究的目标是确定一种药物，它将保护公众免受未来任何使用炭疽作为武器的生物恐怖主义行为的伤害。

DESCRIPTION (provided by applicant): Anthrax Lethal Factor (LF) is a metalloproteinase introduced into the cells of mammalian hosts during infection by the bacterium Bacillus anthracis. LF disrupts intracellular signaling pathways mediated by the MAPKKs, resulting in cell toxicity, sepsis, respiratory failure and rapid death. While antibiotic therapy is effective if given in the first 48 h after symptoms appear, it cannot prevent death if initiated after this narrow therapeutic window. Although exposure to this pathogen is limited in nature, the lethality of anthrax spores as a bioterrorism weapon was demonstrated in the 2001 attacks through the US mail. Novel therapeutics capable of inhibiting the toxic effects of LF are needed to combat late-stage disease. Current treatment methods such as antibiotics, vaccines, and biologic therapies in development, suffer from significant drawbacks. Common to each is an inability to protect cells from the direct effects of LF. These therapies are also vulnerable to next generation genetically modified weapons exploiting LF toxicity. Directly targeting LF activity may allow synergy with current therapies and is the only proposed method of anthrax therapy that may provide rescue during late-stage infection. Use of an LF inhibitor has recently been validated in animals as a therapeutic approach. To date, however, no reported LF inhibitors possess the characteristics needed for a drug capable of protecting the general population in the event of a large scale bioterrorism anthrax attack. The current strategy at Hawaii Biotech Inc. (HBI) employs a three tiered screening cascade using assays designed to identify potent LF inhibitors with good PK properties and efficacy in animal models of anthrax infection. Achievement of this goal will require the continued medicinal chemistry optimization of inhibitors discovered at HBI as well as the identification of new lead series. Computational high throughput docking protocols developed at HBI and tailored specifically towards LF will be used to discover new inhibitors as backups to our current leads. In vitro profiling of compounds to assess potency and selectivity for LF along with molecular modeling of lead series will guide potency optimization. A unique panel of LF mutants prepared at HBI will also be used to guide the design and optimization of novel LF inhibitors. The physicochemical properties, PK, and ADMET characteristics of potent inhibitors will be determined to allow selection of the best candidates for in vivo testing. Finally, the efficacy of potential pre-clinical candidates will be demonstrated in established animal models of anthrax infection. The work proposed in this Phase II Renewal will build on HBI's expert knowledge of LF as a drug target with the goal of identifying an orally bioavailable preclinical candidate that demonstrates in vivo efficacy in a post-exposure animal model of anthrax lethal factor intoxication. The 2001 bioterrorism attack which delivered anthrax spores through the US mail resulted in eleven confirmed cases of the disease and led to five deaths. The current lack of an effective treatment for exposure to anthrax makes a repeat this unfortunate tragedy a real possibility. The goal of this research is to identify a drug which will protect the general public from any future acts of bioterrorism using anthrax as a weapon.