PROSPER is an international Phase III trial demonstrating the beneficial role of enzalutamide, an androgen receptor antagonist, in prolonging metastasis-free survival in men with nonmetastatic castration-resistant prostate cancer. The trial showed that the median metastasis-free survival was 21.9 months longer for those treated with enzalutamide (36.6 months) compared to those treated with placebo (14.7 months). Enzalutamide also showed prolonged time to PSA progression, PSA response, and time to initiating additional antineoplastic therapy although overall survival is not yet reached. Enzalutamide is the second antiandrogen (next to apalutamide) that has gained the United States Food and Drug Administration (US FDA) label indication for use in the setting of nonmetastatic castration-resistant prostate cancer.
Androgen Antagonists/therapeutic use* ; Antineoplastic Agents/therapeutic use* ; Benzamides ; Humans ; Male ; Nitriles ; Phenylthiohydantoin/therapeutic use* ; Prostatic Neoplasms, Castration-Resistant/drug therapy*

Objective: To establish enzalutamide-resistant human prostate cancer cell lines and screen out the lncRNA and mRNA expression profiles associated with enzalutamide resistance. METHODS: Human prostate cancer cell lines LNCAP and C4-2B were cultured with 10 μmol/L enzalutamide for 6 months in vitro for the establishment of enzalutamide-resistant subclones LNCAP-ENZA and C4-2B-ENZA. The IC50 value and enzalutamide resistance index of each cell line were examined by MTT assay, the expressions of enzalutamide-related genes FL-AR, AR-V7 and HnRNPA1 were determined by Western blot, and the lncRNA and mRNA differential expressions of C4-2B and C4-2B-ENZA were detected by high-throughout lncRNA microarray. RESULTS: Compared with LNCAP and C4-2B, the IC50 values of enzalutamide-resistant subclones LNCAP-ENZA (60.83 μmol/L) and C4-2B-ENZA (88.32 μmol/L) were increased significantly (P < 0.05) and the enzalutamide-resistance indexes of the LNCAP-ENZA and C4-2B-ENZA cells were 4.94 and 4.67, respectively. The expressions of AR-V7 and HnRNPA1 were markedly up-regulated in the LNCAP-ENZA and C4-2B-ENZA cells as compared with those in the LNCAP and C4-2B cells, but that of FL-AR showed no significant change. A total of 1 440 lncRNAs and 1 236 mRNAs were identified as differentially expressed in the C4-2B-ENZA cells. CONCLUSIONS Enzalutamide -resistant human prostate cancer cell subclones LNCAP-ENZA and C4-2B-ENZA were successfully established and enzalutamide resistance-associated lncRNA and mRNA were identified, which may provide some molecular evidence for the management of enzalutamide-resistant human prostate cancer.
Cell Line, Tumor ; drug effects ; Drug Resistance, Neoplasm ; Humans ; Male ; Phenylthiohydantoin ; analogs & derivatives ; pharmacology ; Prostatic Neoplasms ; drug therapy ; genetics ; pathology ; RNA, Long Noncoding ; metabolism ; RNA, Messenger ; metabolism ; RNA, Neoplasm ; metabolism ; Receptors, Androgen

Androgen receptor (AR) is a ligand-activated transcription factor that plays a pivotal role in the development and progression of many severe diseases such as prostate cancer, muscle atrophy, and osteoporosis. Binding of ligands to AR triggers the conformational changes in AR that may affect the recruitment of coactivators and downstream response of AR signaling pathway. Therefore, AR ligands have great potential to treat these diseases. In this study, we searched for novel AR ligands by performing a docking-based virtual screening (VS) on the basis of the crystal structure of the AR ligand binding domain (LBD) in complex with its agonist. A total of 58 structurally diverse compounds were selected and subjected to LBD affinity assay, with five of them (HBP1-3, HBP1-17, HBP1-38, HBP1-51, and HBP1-58) exhibiting strong binding to AR-LBD. The IC values of HBP1-51 and HBP1-58 are 3.96 µM and 4.92 µM, respectively, which are even lower than that of enzalutamide (Enz, IC = 13.87 µM), a marketed second-generation AR antagonist. Further bioactivity assays suggest that HBP1-51 is an AR agonist, whereas HBP1-58 is an AR antagonist. In addition, molecular dynamics (MD) simulations and principal components analysis (PCA) were carried out to reveal the binding principle of the newly-identified AR ligands toward AR. Our modeling results indicate that the conformational changes of helix 12 induced by the bindings of antagonist and agonist are visibly different. In summary, the current study provides a highly efficient way to discover novel AR ligands, which could serve as the starting point for development of new therapeutics for AR-related diseases.
Androgen Receptor Antagonists ; pharmacology ; Androgens ; metabolism ; pharmacology ; Biological Assay ; Cell Line, Tumor ; Drug Discovery ; methods ; Humans ; Ligands ; Male ; Molecular Docking Simulation ; Molecular Dynamics Simulation ; Phenylthiohydantoin ; analogs & derivatives ; pharmacology ; Principal Component Analysis ; Prostatic Neoplasms ; drug therapy ; Protein Binding ; physiology ; Protein Conformation ; drug effects ; Receptors, Androgen ; metabolism

Despite impressive survival benefits with immunotherapy in patients with various solid tumors, the full potential of these agents in prostate cancer has yet to be realized. Sipuleucel-T demonstrated a survival benefit in this population, indicating that prostate cancer is an immunoresponsive disease; however, these results have not been matched by other agents. A large trial with ipilimumab in prostate cancer failed to meet its primary objective, and small trials with PD-1/PD-L1 inhibitors did not yield a significant improvement in overall response. However, several late-stage clinical trials are underway with other vaccines in prostate cancer. Reports of clinical benefit with immunotherapies, particularly when used in combination or a select population, have provided the framework to develop sound clinical trials. Understanding immunogenic modulation, antigen spread, biomarkers, and DNA-repair defects will also help mold future strategies. Through rational patient selection and evidence-based combination approaches, patients with prostate cancer may soon derive durable survival benefits with immunotherapies.
Animals ; Antineoplastic Agents, Immunological/therapeutic use* ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; B7-H1 Antigen/antagonists & inhibitors* ; Benzamides ; CTLA-4 Antigen/antagonists & inhibitors* ; Cancer Vaccines/therapeutic use* ; Humans ; Immunotherapy ; Ipilimumab/therapeutic use* ; Male ; Nitriles ; Phenylthiohydantoin/analogs & derivatives* ; Programmed Cell Death 1 Receptor/antagonists & inhibitors* ; Prostatic Neoplasms/drug therapy* ; Tissue Extracts/administration & dosage*