Discovery And Structure-Activity Relationship Of Novel Isocitrate Dehydrogenase 2(IDH2) Inhibitors

The metabolism reprogramming of cancer cells plays an important role in the initiation and maintenance of tumors.Some enzymes affecting the metabolic pathways have been considered as important targets for cancer therapy.Isocitrate dehydrogenase?IDH?are critical knots that interconvert isocitrate and?-ketoglutarate??-KG?.?-KG is an important metabolic intermediate in the tricarboxylic acid cycle?TCA?and connects intracellular carbon-nitrogen metabolism,not only directly participates in energy supply,but also participates in a variety of chemical reactions in the cell,which plays an important role in maintaining normal physiological functions of the body.Once IDH mutations happen,for example,in IDH1?R132?or IDH2?R140 and R172?,mutant IDH?mIDH?will in turn catalyze the production of the oncometabolite 2-hydroxyglutarate?2-HG?.The overproduced 2-HG can competitively inhibit?-KG-dependent dioxygenase,cause cell differentiation disorders and promote tumorigenesis and development.IDH mutations have been found in a variety of diseases,including acute myeloid leukemia?AML?,glioma and myelodysplastic syndrome?MDS?.By inhibiting the activity of mIDH,the level of 2-HG can be reduced to reverse cell differentiation disorders and inhibit the occurrence and development of mutant-specific tumors.At present,two mIDH-specific inhibitor drugs have been approved for marketing,and many molecules have entered clinical trials.AG-221 is a selective inhibitor of the mutant IDH2 enzyme that shows excellent clinical outcomes and has been approved for the treatment of recurrent and refractory acute myeloid leukemia by Food and Drug Administration?FDA?in 2017.In this thesis,according to the discovery and structure-activity relationship?SAR?of new mIDH2 inhibitors,the design,synthesis and activity evaluation of macrocyclic mIDH2 inhibitors based on conformational restriction strategies and the discovery of new mIDH2 inhibitors with novel skeletons based on virtual screening were carried out as follows:Design,synthesis and activity evaluation of macrocyclic mIDH2 inhibitors:Conformational restriction is one of the most effective approaches for compounds design,which has been widely applied in drug discoveries.The macrocycle ring enables a compound to achieve a degree of structural pre-organization,so that key functional groups can interact across extended binding sites in proteins without a major entropic loss due to free rotation,therefore improving the activity and selectivity of the compound.This strategy has been successfully applied to the discovery of inhibitors of hepatitis C virus?HCV?NS3 protease,matrix metalloproteinase?MMP?,?-secretase and others.In this thesis,a macrocyclic strategy based on conformational restriction was applied to the study of mIDH inhibitors.Using AG-221 as a lead compound,a series of macrocyclic skeletons with different linkers were designed and synthesized,and a total of 33compounds in six series were obtained.The activity test results showed that most of the compounds showed excellent IDH2-R140Q,IDH2-R172K inhibitory activity and inhibitory activity of 2-HG production in IDH2 mutant TF-1 cells,which were comparable to or better than the positive control AG-221.It was also found that some compounds were significantly different from AG-221 on different mIDH2,providing experimental basis and entry points for subsequent optimization of the lead molecule.The representative compound C6 showed good in vivo pharmacokinetic properties,and its oral bioavailability was 19.8%.Further computational docking and kinetic simulation results show that C6 displayed strong binding to IDH2-R140Q,and the binding mode was similar to AG-221.In summary,compound C6 has the potential for further development,and subsequent in vivo activity tests and optimization are ongoing.Discovery of new mIDH2 inhibitors based on virtual screening:Virtual screening has become an important and widely used method for discovering novel hits or leads.The appliance of virtual screening can give guidance for rational optimization of compounds,and therefore improving the success rate and lowering the cost during drug development.Structure-based virtual screening?SBVS?refers to studying the binding of candidate compounds to target proteins by molecular docking on the three-dimensional structures of target proteins obtained from X-ray,nuclear magnetic resonance?NMR?or homology modeling technology.And the docking scoring is often used to predict whether they are potential hits.In this thesis,mIDH2 was used as targets.Through a systematic virtual screening model study,5I96_B was identified as the receptor model for molecular docking,and Glide HTVS docking,Glide SP docking,Glide XP docking and other standard screening processes were developed.A virtual screening based on a commercial compound library was carried out.After MM-GBSA and visual selecting,30 hit compounds were selected from the Chemdiv database containing 1200000 compounds and subjected to in vitro IDH2-R140Q inhibitory potency evaluation.As a result,compound XS-1,XS-10 and XS-16 were successfully identified,exhibiting IC₅₀ values of 6168.0 nM,1951.5 nM and350.2 nM,respectively.Among them,XS-16 exhibits the best activity,and its triazolo pyrimidin skeleton is novel,which is significantly different from the IDH2 inhibitor framework reported in the literature,showing its potential to be further developed as a new mIDH2 inhibitor.In summary,by constructing macrocyclic mIDH2 inhibitors,we discovered compound C6 with higher IDH2-R140Q inhibitory potency,good in vitro 2-HG inhibition activity and in vivo pharmacokinetic properties;Through virtual screening,the triazole pyrimidine lead compound XS-16 with superior activity and novel skeleton was obtained.Both of them provide important structural basis for the development of new mIDH2 inhibitors.