Using Existing Drugs as Leads for Broad Spectrum Anthelmintics Targeting Protein Kinases

As one of the largest protein families, protein kinases (PKs) regulate nearly all processes within the cell and are considered important drug targets. Much research has been conducted on inhibitors for PKs, leading to a wealth of compounds that target PKs that have potential to be lead anthelmintic drugs. Identifying compounds that have already been developed to treat neglected tropical diseases is an attractive way to obtain lead compounds inexpensively that can be developed into much needed drugs, especially for use in developing countries. In this study, PKs from nematodes, hosts, and DrugBank were identified and classified into kinase families and subfamilies. Nematode proteins were placed into orthologous groups that span the phylum Nematoda. A minimal kinome for the phylum Nematoda was identified, and properties of the minimal kinome were explored. Orthologous groups from the minimal kinome were prioritized for experimental testing based on RNAi phenotype of the Caenorhabditis elegans ortholog, transcript expression over the life-cycle and anatomic expression patterns. Compounds linked to targets in DrugBank belonging to the same kinase families and subfamilies in the minimal nematode kinome were extracted. Thirty-five compounds were tested in the non-parasitic C. elegans and active compounds progressed to testing against nematode species with different modes of parasitism, the blood-feeding Haemonchus contortus and the filarial Brugia malayi. Eighteen compounds showed efficacy in C. elegans, and six compounds also showed efficacy in at least one of the parasitic species. Hypotheses regarding the pathway the compounds may target and their molecular mechanism for activity are discussed.

作为最大的蛋白质家族之一，蛋白激酶（protein kinases, PKs）几乎调控细胞内的全部生理过程，被视为关键的药物靶点。目前学界已针对PKs开展了大量抑制剂相关研究，积累了大量靶向PKs的化合物，其中部分有望开发为抗蠕虫先导药物。筛选已获批用于治疗被忽视热带病的化合物，是一种极具吸引力的低成本先导化合物开发策略，可快速获取可转化为临床急需药物的候选分子，尤其适配发展中国家的用药需求。本研究首先从线虫、宿主及DrugBank数据库中鉴定PKs，并将其归类至相应的激酶家族与亚家族；将线虫蛋白划分为覆盖整个线虫门的直系同源群组；鉴定出线虫门的最小激酶组，对其特征展开探究。基于秀丽隐杆线虫（Caenorhabditis elegans）直系同源基因的RNA干扰（RNA interference, RNAi）表型、生命周期转录表达谱及解剖学表达模式，对最小激酶组中的直系同源群组进行实验测试优先级排序。提取DrugBank中与线虫最小激酶组内同家族、同亚家族靶点相关的化合物，对35种化合物开展非寄生性模式生物秀丽隐杆线虫的活性测试；对显示出活性的化合物，进一步针对两种不同寄生模式的线虫物种展开测试：吸血寄生的捻转血矛线虫（Haemonchus contortus）以及丝虫类的马来布鲁线虫（Brugia malayi）。实验结果显示，18种化合物在秀丽隐杆线虫中表现出驱虫活性，另有6种化合物在至少一种寄生线虫物种中同样具有活性。本研究最后探讨了这些化合物可能靶向的信号通路及其发挥活性的分子机制。