Design,synthesis And Preliminary Biological Activity Study Of MutIDH1 Inhibitors And PROTACs

IDH1 is a subtype in the isocitrate dehydrogenase（IDH）family.It plays an important role in the tricarboxylic acid cycle and can participate in the reaction of catalyzing the conversion of isocitrate toα-ketoglutarate（α-KG）.However,when IDH1 is mutated,it cannot exert such catalytic ability.In contrast,it reducesα-KG to2-hydroxyglutaric acid（2-HG）,and the accumulation of the compound in cells will competitively inhibitα-KG-dependent dioxygenase activity,which inhibits cell differentiation and eventually promotes normal cells into tumors.The discovery of the carcinogenic mechanism of mutIDH1 makes this target attract the attention of many researchers.The first high-efficiency IDH1 inhibitor discovered by high-throughput screening was AGI-5198 developed by Agios,but due to the poor metabolic stability,it could not be further applied for clinical treatment.Subsequently,the company launched AG-120 based on the chemical structure of AGI-5198,which was approved by the FDA in July 2018.With the continuous development of different mutIDH1inhibitors,their defects in clinical research are also highlighted,the most serious of which is the impact of drug resistance and off-target effects on patients.Proteolysis targeting chimera（PROTACs）are a kind of bifunctional small molecules.It consists of target protein ligands,E3 ligand and linker.PROTACs form a ternary complex（target proteins-PROTACs-E3）with the target protein and E3ubiquitin ligase when they play a role in the human body,and then induce the target protein to degrade through the"ubiquitin-proteasome system".Now,the research of PROTACs involves targets that span sex hormone receptors,Tau protein,and cancer cell-associated kinases.The types of diseases involved include cancer and neurodegenerative diseases.At present,two oral PROTACs have entered the clinical trials for the treatment of prostate cancer and breast cancer.Although the target proteins targeted by the mainstream research institutes of PROTACs have not yet involved the mut IDH series,the research on small molecule inhibitors targeted by mutIDH1 has achieved a large number of staged results that have met the needs of the introduction of PROTACs.The specificity and good targeting of mutIDH1 small molecule inhibitors are endless,which also laid the foundation for the development of PROTACs technology in this field.In order to improve the research status of mutIDH1 targeted drugs,this paper proposes two solutions through the study of a large number of documents:1.Continue to invest in the research and development of new mutIDH1 targeted inhibitors,the application of new inhibitors will expand the range of the mutIDH1 inhibitors available.Previously,researchers have found that Clomifene has a good ability to inhibit IDH1-R132H through virtual screening,and can selectively inhibit the activity of mutant enzymes in a dose-dependent manner,thereby reducing the intracellular2-hydroxyglutarate accumulation reduces the chance of normal cell tumorigenesis.The results show that Clomifene has the clinical potential to be a safe and effective mutIDH1 inhibitor.2.Introducing new therapeutic strategies of PROTACs into the development of mutIDH1 targeted drugs to fundamentally block the defects of small molecule inhibitors.Based on the above two solutions,the research work of this project is as follows:In this paper,based on the lead compound Clomifene(IC₅₀=50μM),through the analysis of the chemical structure of AGI-5198,AG-120 and other highly effective inhibitors,the application of bioisosterism,skeleton hopping and other effective and practical chemical means,a total of 43 Clomifene-derived compounds and intermediates in 4 categories were designed and synthesized.After that,IDH1-R132H was used as the target protein to screen the activity of these compounds.The screening results showed that 40%（17 kinds）of the target compound showed higher inhibitory activity than Clomifene,of which the compound 8 had the most prominent inhibitory activity,and the inhibitory ability shown in the preliminary screening was about triple in ability compared to Clomifene.The above preliminary screening results indicate that Clomifene-derived compounds have great clinical potential in the development of mutIDH1 inhibitors,but there is also a problem that the overall inhibitory activity of the derivative compounds is far from the inhibitory ability of high-efficiency inhibitors such as AG-120.It is necessary to improve the suppression ability through further structural optimization for Compound 8.In the PROTACs section,through careful screening of known small molecule inhibitors and E3ubiquitin ligase ligands,the intermediates and derivatives of AGI-5198 and the marketed drug Ivosidenib（AG-120）were finally determined as the mutIDH1 Ligands,using pomalidomide as the CRBN E3 ubiquitin ligase ligand,designed by medicinal chemistry methods,synthesized four different chain length and composition structure（alkyl chain or PEGs chain）PROTACs small molecules,And initially established a binary complex chemistry toolbox composed of pomalidomide and different linkers.The establishment of the toolbox can facilitate the chemical synthesis of PROTACs later.After active screening of the above ligands and PROTACs molecules,it was found that the target protein ligand 1（48）and IP-01（66）(IC₅₀were 28.99±0.1μM and 34.47±0.1μM,respectively)showed strong inhibitory activity However,there is still a gap between the nanomolar suppression capability of the original design..The research content of the inhibitors laid a solid foundation for the continued development of Clomifene-derived compounds in mutIDH1 inhibitors,and provided a basis for structural optimization for the development of this series of new inhibitors.The research content of the PROTACs section provides an optimized basis for the structural modification of the PROTACs molecules and target protein ligands;it provides convenience for the design and synthesis of different PROTACs molecules;it will lay a solid foundation for the experiment of vitro target protein affinity and vivo target protein degradation.In a word,this article believes that the research and development of PROTACs drugs should be complementary to small molecule inhibitors,keep pace with the times,and ultimately provide a more complete drug treatment plan for patients with mutIDH1 related tumors.