Novel molecular therapeutics for cystic fibrosis

描述(申请人提供)：囊性纤维化(CF)导致慢性疾病、残疾和过早死亡。反复肺部感染是致命的，因为细菌和其他微生物在异常粘稠的粘液中生长。抗生素、粘液剂和抗炎药仅在治疗某些CF效应时有用。然而，最近，iVacaftor(又名VX-770或Kalydeco)，解决了CF的根本原因，得到了FDA的批准。不幸的是，它对大多数患者无效。CF的潜在原因是囊性纤维化跨膜电导调节因子(CFTR)的突变，该调节因子通常定位于细胞膜并控制盐分水平。在CF中，突变降低了CFTR的数量或活性，由此产生的盐调节失调导致了CF的病理。主要的突变(美国为90%，全球为约75%)是F508，即CFTR中一个苯丙氨酸残基的缺失。F508导致CFTR的错误折叠，其中大部分在内质网(ER)中降解，不能到达细胞膜。F508如果能定位到细胞膜上就有部分功能，并且正在开发诸如VX-809/Lumacaftor之类的“校正”药物来促进突变的CFTR向细胞表面的运输。通过干预调节蛋白质的各种细胞途径，包括泛素/蛋白酶体途径，人们正在寻找增加CFTERF508水平、运输和/或功能的其他方法。错误折叠的CFTR？F508被泛素E3连接酶gp78泛素化，并通过ERAD(内质网相关蛋白降解)降解，降低其细胞水平。Gp78基因的敲除导致细胞内CFTERF508水平显著增加，并增加了氯的转运。因此，抑制gp78应该会增加细胞表面cftr的数量，并且可能单独有用，也可能与VX-809等校正剂联合使用。在第一阶段，确定了gp78的小分子抑制剂，并证明了它们增加功能性CFTR水平的能力，正如细胞分析所判断的那样。其中一种HITS(GP1)增加了核心糖基化CFTR？F508的水平，当与VX-809联合使用时，增加了细胞中功能性CFTR？F508的水平，进一步验证了gp78作为治疗CF的靶点。在第二阶段，GP1和其他HIT化合物将通过药物化学优化得到改进，通过体外和基于细胞的二次分析进行分析，并在动物模型中进行药物代谢/药代动力学特性测试，目的是确定有效和选择性的先导化合物，作为囊性纤维化的治疗剂。

DESCRIPTION (provided by applicant): Cystic fibrosis (CF) leads to chronic illness, disability, and early death. Recurrent pulmonary infections are lethal owing to growth of bacteria and other microorganisms in the abnormally viscous mucus. Antibiotics, mucolytics, and anti-inflammatory agents, are useful only in treating some CF effects. Recently, however, ivacaftor (a.k.a. VX-770 or Kalydeco), which addresses the underlying cause of CF, was approved by the FDA. Unfortunately, it is ineffective in a majority of patients. The underlying cause of CF is a mutatio of the cystic fibrosis transmembrane conductance regulator (CFTR), which normally localizes to the cell membrane and controls salt levels. In CF, a mutation decreases the amount or activity of CFTR, and the resultant salt dysregulation leads to CF pathologies. The primary mutation (> 90% in the US and ~75% worldwide) is ¿F508, deletion of a single phenylalanine residue in CFTR. ¿F508 causes improper folding of CFTR, most of which is degraded in the endoplasmic reticulum (ER) and does not reach the cell membrane. CFTR¿F508 is partially functional if it can be localized to the membrane, and "corrector" drugs such as VX-809/lumacaftor are being developed to promote trafficking of mutant CFTR to the cell surface. Additional ways of increasing the levels, trafficking, and/or functionality of CFTR¿F508 are being sought by intervening in various cellular pathways that regulate proteins, including the ubiquitin/proteasome pathway. Misfolded CFTR¿F508 is ubiquitylated by the ubiquitin E3 ligase gp78 and degraded via ERAD (endoplasmic reticulum associated protein degradation), decreasing its cellular level. Knockdown of gp78 leads to dramatically increased levels of CFTR¿F508 in cells and increases chloride transport. Thus gp78 inhibition should increase the amount of CFTR at the cell surface and may be useful alone or combined with correctors such as VX-809. In phase I, small molecule inhibitors of gp78 were identified and their ability to increase levels of functional CFTR, as judged by cellular assays, demonstrated. One of these hits (GP1) increased the level of core glycosylated CFTR¿F508 and, when combined with VX-809, increased the level of functional CFTR¿F508 in cells, providing further validation of gp78 as a target for the treatment of CF. In Phase II, GP1 and additional hit compounds will be improved by medicinal chemistry optimization, analyzed by in vitro and cell-based secondary assays, and tested in animal models for drug metabolism/pharmacokinetic properties, with the goal of identifying potent and selective lead compounds with efficacy as therapeutic agents for cystic fibrosis.