靶向ERK2激酶的抑制剂活性筛选与机理研究

Bioassay screening and binding mode study of inhibitors targeting at ERK2

关键词:  细胞外信号调节激酶2（ERK2）  分子对接  蛋白表达  活性筛选  结合模式

Key words:  Extracellular regulated protein kinase2 (ERK2)  Molecular Docking  Protein Expression  Bioassay Screening  Binding Mode

摘要:

细胞外信号调节激酶2(Extracellular Regulated Protein Kinase2，ERK2)是恶性肿瘤发生、发展过程中的关键激酶，目前还没有靶向ERK2的药物获批上市。本研究旨在获得结构新颖的靶向ERK2小分子抑制剂。通过质粒构建、蛋白表达与体外激酶活性测试，对本实验室构建的北部湾次级代谢产物及化学合成化合物库中的化合物开展生物活性筛选，利用分子对接阐明化合物与ERK2激酶的结合模式及作用机理。最终筛选获得6-甲氧基红镰霉素B、异红镰霉素及嘧啶脲类共5个具有较高抑制剂活性的化合物1-5，其半抑制浓度（IC50）分别为（4.17±1.82）、（13.39±0.93）、（27.85±2.55）、（19.14±1.02）和（8.55±3.72） μmol/L。本研究发现化合物1-5与ERK2激酶中 LYS-54、MET-108及GLN-105残基形成的氢键作用是影响两者结合稳定性的关键因素，明确了化合物1-5对ERK2激酶具有抑制活性，为靶向ERK2的药物设计提供了参考。

Abstract:

Extracellular signaling regulatory kinase 2 (ERK2) is a key kinase involved in the development and progression of malignant tumors. Currently, there is not FDA approved drugs specially targeting at ERK2 kinase. In order to explore structurally novel inhibitors targeting at ERK2 kinase, we constructed hERK2 plasmid for protein expression and kinase activity assays in vivo. we conducted bioassay screening on in-house molecular library, which consists of natural product isolated from Beibu gulf and chemically synthesized compounds of interest. Molecular docking was also employed to elucidate the binding modes and mechanisms of these compounds with the ERK2 kinase. Five hit compounds, designated compound 1-5, including 6-methoxy-rubrofusarin B, isorubrofusarin and 2-pyridyl urea with IC50 of 4.17±1.82, 13.39±0.93, 27.85±2.55, 19.14±1.02 and 8.55±3.72 μmol/L were identified, respectively. We found that the hydrogen-bonding interactions formed with residues of LYS-54, MET-108 and GLN-105 were the key factors affecting the stability of receptor-ligand binding and demonstrated that compound 1-5 exhibited inhibitory activity on ERK2 kinase. These results would be benefit to the drug discovery of targeting at ERK2 kinase.