The Design, Synthesis And Bioactivity Evaluation Of Small-molecule Inhibitors Of TrxR1

Studies have shown that the thioredoxin system is closely related to many diseases.Thioredoxin reductase(TrxR),the key enzyme of the thioredoxin system,exists in mammalian cells in three main forms of TrxR1,TrxR2 and TrxR3.And the thioredoxin system is critical to maintain the balance of REDOX and regulates the redox-related signaling pathways in organisms.TrxR regulates various redox-related downstream biochemical processes by reducing thioredoxin(Trx)and other substrates,such as ROS levels,cell proliferation,cell differentiation,and apoptosis.In recent years,a large number of studies have demonsteated that TrxR1 is overexpressed in tumor tissues,and its expression level is bound up with the proliferation,metastasis ability,and drug resistance of tumor cells.The existing clinical drugs,such as Auranofin and cisplatin,can specifically inhibit TrxR1and induce the increase of ROS and thus induce the apoptosis of tumor cell,and achieve a satisfactory prognosis in clinical application.The purpose of this study is to design and synthesize a novel small molecule inhibitor targeting TrxR1 by virtual screening technology,then optimize its biological activity,improve its specificity and increase its potential as a drug,and finally put it into clinical application.Virtual screening is a kind of technology,which utilizes computer software to extract the target compounds from chemical database,The main advantages are that it can significantly reduce the cost and time of scientific research and improve the efficiency of drug discovery.Structure-based virtual screening(SBVS)means that in the case of the structure of target protein is definite,the compounds are firstly docked with the active sites of the target proteins to predict the patterns of their interaction,and then the target docked molecules are ranked and screened by sequencing or combining with other indicators.In this paper,based on the three-dimensional structure of TrxR1,virtual screening was conducted for small molecules downloaded from ZINC small molecule library.By predicting and evaluating the binding energy,ligand efficiency and binding pattern of each molecule with TrxR1,267 potential active molecules were screened out.By analyzing the structure of these 267 small molecules and the binding pattern between the small molecules and the target protein,four parent nuclei were extracted.Forty compounds were designed by fragment growth strategy.Then,based on the cutting method,the retrosynthetic analysis of the designed compounds was implemented and a feasible synthesis route was found.In this paper,a total of 40 compounds were synthesized and their structures were characterized by ~1H-HMR.Finally,in vitro experiments were carried out to evaluate the enzyme inhibitory activity of the compounds,and six molecules exerting excellent effect,including A11,B4,B3,C1,C8,C9,were screened out.Moreover,the interaction model between A11and TrxR1 was predicted and analyzed through molecular docking and molecular dynamics simulation,which laid a foundation for the subsequent optimization of the compound.