Design,Synthesis And Bioactivity Evaluation Of Small Molecule PROTACs Targeting AR

Proteolytic targeting chimera(PROTAC)is a new technology for inducing protein degradation and has been widely used in the field of anti-tumor drug research.The PROTAC molecule has been designed to degrade a growing number of proteins and used to treat a variety of diseases.As a potential anti-tumor drug,it has the advantages of high selectivity and low toxicity.After castration treatment of prostate cancer(PCa),some cancer cells acquire the ability to rely on low concentration of androgens for growth and the ability to resist apoptosis,which eventually leads to the development of PCa into castration-resistant prostate cancer(CRPC).During the transformation process,the androgen receptor(AR)signaling pathway is activated by a variety of molecular mechanisms and promotes the progress of CRPC.Small molecule inhibitor drugs are widely used in clinical treatment of CRPC,but with the mutation of AR itself and other reasons,the reactivation of AR signaling pathway is diversified,which makes cancer cells gradually develop drug resistance to the drug.The application of PROTAC technology to the treatment of PCa can directly degrade AR protein,rather than inhibit AR protein,providing a new strategy for solving the problems of drug resistance and off-target toxicity.Therefore,some PROTAC molecules were designed and synthesized to induce AR protein degradation,and their biological activities were investigated in this study.Nine small molecule PROTAC compounds were designed and synthesized by combining thalidomide and its analogues,which bind to ubiquitin ligase of the CRBN system E3,and AR agonists or inhibitors,which bind to AR proteins.After preliminary cell activity test,PAP508 was obtained with better inhibitory effect on cancer cells.After that,the activity of PAP508 was further evaluated on LNCaP and VCaP cells.In the cell proliferation test,PAP508 had better anti-proliferation effect than the positive drug(Enzalutamide).Western blot experiment showed that PAP508 induced AR protein degradation by concentration and time dependence,and its degradation was proteasome dependent.In addition,PAP508 could effectively inhibit the migration and invasion of prostate cancer cells.Finally,through the detection of apoptosis kit,it was found that PAP508 can induce apoptosis.On this basis,western blot experiments on apoptotic gene-related proteins were designed,which proved that PAP508 could promote the expressions of pro-apoptotic gene-related proteins.Therefore,PAP508 can effectively degrade AR protein,inhibit the proliferation of prostate cancer cells and promote apoptosis.Further exploration of biological activity and optimization of its structure based on PAP508 will provide a theoretical basis for the treatment of prostate cancer with AR targeting PROTAC molecule and boost the development of such new drugs.