Design, Structure Optimization And Bioactivity Evaluation Of Novel Ar Antagonists

Prostate cancer（PCa）is a malignant disease wide among men in developed countries such as Europe and the United States.The incidence and mortality of the desease is extraordinarily high.Along with the improvement of life quality and the increase of aging population,the incidence of PCa in China is also continusingly increasing.Moreover,most of the diagnosed patients are already in the middle and advanced stages of the disease,and usually soon develop into castration-resistant prostate cancer（CRPC）after anti-androgen treatment,facing a difficult situation for further therapy.Androgen receptor（AR）signaling is still a major driver fator for CRPC.And AR antagonist is one of the most important drugs to treat CRPC.The first-generation non-steroidal AR antagonists such as flutamide and bicalutamide work by competitively binding to AR ligand binding pocket（LBP）.The second-generation AR antagonists such as enzalutamide（Enz）can function additionally by blocking AR nuclear translocation.Unfortunately,drug resistances appeared for all the approved AR antagonists.One significant major reason is that the amino acid mutations on AR LBP convert AR antagonists to agonists.It is extremely urgent to search and discover novel AR antagonists.The first part of the thesis focuses on AR,introducing its structure,function,mechanism of action,related cancers and drugs.In addition,the mechanisms of drug resistances emerged in CRPC are summarized.In general,the research background of the project is comprehensively described in this part,hopefully providing useful information for reference.The second part of the thesis is about the structure-based virtual screening（SBVS）of AR antagonists and the discovery of the bioactive compound C18.Through hierarchical SBVS targeting AR,32 compounds were selected from the the Specs database by standard precision（SP）and extra precision（XP）of molecular docking software Glide,variable dielectric-molecular mechanics/generalized born surface area（VD-MM/GBSA）,and cluster analysis.Afterwards,these compounds were examed through bioassays such as transcriptional activity assay,toxicity test,ligand displacement assay and so on,and a potential AR antagonist C18 was screened out.C18 antagonized AR transcriptional activity with an IC₅₀ value of 2.4μM comparable to that of Enz(IC₅₀=0.08μM)and reduced the expression of prostate-specific antigen（PSA）with IC₅₀ of 1.4μM(Enz IC₅₀=0.13μM).Moreover,C18 binds to the AR LBP in a dose-dependent fashion(IC₅₀=4.03μM),indicating that C18 could directly target the LBP.The third part of the thesis is the structural optimization of C18 and the discovery of the bioactive compound AT2.We performed molecular dynamics（MD）simulation based on C18 and obtained a series of dynamic AR-C18 complex structures.On the basis of these structures,rational drug design and structure-activity relationships（SAR）analysis were carried out,and then three series of C18 analogues（AT-CT series）were finally purchased and synthesized.Further biological assays were conducted for the analogues at the cellular and molecular levels.Finally,a novel AR antagonist AT2 with overall good activities(AR transcriptional inhibition IC₅₀=0.15μM;PSA expression inhibition IC₅₀=0.43μM;capable of blocking AR nuclear translocation)was obtained,and the relevant patent application was already submited.The project involves SBVS and bioactivity assays in the early stage,and then MD simulation and analogue screening in the later stage,finally achieving a novel AR antagonist AT2.It provides the basis and ideas for the development of new therapeutics against PCa.