Virtual Screening And Biological Evaluation Of Noval 4-hydroxyquinoline Derivatives As IDO1 Inhibitors

BackgroundThe immunological checkpoint molecule is an important barrier for the body to monitor the growth and proliferation of tumor cells in vivo.Because the immune signal pathway is complicated,and the immune cells,cytokines and immune adjuvants in the tumor microenvironment interact with each other,only the single target drug therapy The effect needs to be improved,and it is also easy to cause adverse reactions.Indoleamine2,3-dioxygenase 1?IDO1?is the rate-limiting enzyme in the metabolism of tryptophan in humans.It is also a key immunosuppressive enzyme that regulates the immune response of tumors.The key amino acid?tryptophan?inhibits the proliferation of immune cells,thereby preventing the body's natural immune response to cancer cells.IDO1 is currently overexpressed in tumor cells and is considered a potential small molecular target for tumor immunotherapy.IDO1 inhibitors can inhibit the metabolism of tryptophan and increase the immune response,thereby achieving the purpose of inhibiting tumors.Up to now,no IDO1 inhibitors have been listed,and the structure of IDO1 inhibitors is still limited to terpenoids,aryl imidazoles and hydroxyimidazoles.Therefore,the development of new backbone type IDO1 inhibitors is still of great significance.Research objectiveIn this study,the ZINC and Chembridge databases were screened by virtual screening techniques such as molecular docking and pharmacophore model using computer-aided drug design methods,and IDO1 inhibitors of new skeleton structures were discovered by enzyme activity and cell activity verification.Research methods1.According to the structure of the IDO1 protein crystal,the active site and its ligand binding site,the ZINC database was screened by molecular docking method to obtain the seed compound.2.The recombinant plasmid pET28a?+?-hIDO1 was constructed by genetic engineering and purified to obtain the recombinant human IDO1 protein.The IDO1activity detection system was established and the virtual screening compound was used as the target for primary screening.3.The lead compound analogues were virtually screened and tested for enzyme activity based on the pharmacophore model;Molecular dynamics simulations were used to verify the binding mode of the compounds to the IDO1 protein crystals.4.The HEK293T cell line stably transfected with IDO1 gene was established,and the activity of the lead compound analog was verified.Research results1.Using IDO1 as the target,11 pilot compounds were obtained by virtual screening of ZINC database based on molecular docking.According to the docking score and binding mode of ligand molecule and IDO1 receptor,it was found that the binding of ZINC91657208 and IDO1 crystal was the most stable.2.By Using IDO1 activity detection system,11 compounds were screened.Among them,ZINC91657208 with skeleton of 4-hydroxyquinoline could inhibit the enzyme activity of IDO1 with IC₅₀ value of 77.15?mol/L.3.And 10 compounds were selected by pharmacophore virtual screening and measured their inhibitory of the enzyme activity of IDO1.Among the 3 compounds showed obvious activity,Chembridge29374490 had lowest IC₅₀ with value of 37.78?mol/L;The interaction mode of Chembridge22054105 and Chembridge29374490 was verified by molecular dynamics simulation and they were found to be stably bound to the binding pocket of IDO1 crystal.4.It was further verified by cell viability that the inhibition rate of Chemqiao29374490and INCB024360 was more than 80%at the concentration of 4-hydroxyquinoline at 100?mol/L,indicating that 4-hydroxyquinoline is a new type of IDO1 inhibitor.Further research and development of new and efficient IDO1 inhibitors laid the foundation.