thiohydantoins and bicalutamide

A high incidence of fall and fracture in a subset of patients treated with androgen receptor inhibitors (ARIs) has been reported, although the relative risk (RR) of fall and fracture for patients who receive ARI treatment is unknown.. To evaluate whether treatment with ARIs is associated with an elevated relative risk for fall and fracture in patients with prostate cancer.. Cochrane, Scopus, and MedlinePlus databases were searched from inception through August 2019.. Randomized clinical trials comparing patients with prostate cancer treated with any ARI or placebo were included.. Two independent reviewers used a standardized data extraction and quality assessment form. A mixed effects model was used to estimate the effects of ARI on relative risk, with included studies treated as random effects and study groups treated as fixed effects in the pooled analysis. Sample size for each study was used to weight the mixed model. Statistical analysis was performed from August to October 2019.. The primary outcome was RR of fall and fractures for patients receiving ARI treatment.. Eleven studies met this study's inclusion criteria. The total population was 11 382 men (median [range] age: 72 [43-97] years), with 6536 in the ARI group and 4846 in the control group. Participants in the ARI group could have received enzalutamide, apalutamide, or darolutamide in combination with androgen deprivation therapy or other enzalutamide combinations; patients in the control group could have received placebo, bicalutamide, or abiraterone. The reported incidence of fall was 525 falls (8%) in the ARI group and 221 falls (5%) in the control group. The incidence of fracture was 242 fractures (4%) in the ARI group and 107 fractures (2%) in the control group. Use of an ARI was associated with an increased risk of falls and fractures: all-grade falls (RR, 1.8; 95% CI, 1.42-2.24; P < .001); grade 3 or greater fall (RR, 1.6; 95% CI, 1.27-2.08; P < .001); all-grade fracture (RR, 1.59; 95% CI, 1.35-1.89; P < .001), and likely grade 3 or greater fracture (RR, 1.71; 95% CI, 1.12-2.63; P = .01).. Use of ARI was associated with an increase in falls and fractures in patients with prostate cancer as assessed by a retrospective systematic review and meta-analysis. Further studies are warranted to identify and understand potential mechanisms and develop strategies to decrease falls and fractures associated with ARI use.

Topics: Abiraterone Acetate; Accidental Falls; Androgen Receptor Antagonists; Anilides; Antineoplastic Agents, Hormonal; Benzamides; Case-Control Studies; Fractures, Bone; Humans; Incidence; Male; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; Pyrazoles; Risk Factors; Thiohydantoins; Tosyl Compounds; Trauma Severity Indices

The combination of radiotherapy with bicalutamide is the standard treatment of prostate cancer patients with high-risk or locally advanced disease. Whether new-generation anti-androgens, like apalutamide, can improve the radio-curability of these patients is an emerging challenge.. We comparatively examined the radio-sensitising activity of apalutamide and bicalutamide in hormone-sensitive (22Rv1) and hormone-resistant (PC3, DU145) prostate cancer cell lines. Experiments with xenografts were performed for the 22Rv1 cell line.. Radiation dose-response viability and clonogenic assays showed that apalutamide had a stronger radio-sensitising activity for all three cell lines. Confocal imaging for γΗ2Αx showed similar DNA double-strand break repair kinetics for apalutamide and bicalutamide. No difference was noted in the apoptotic pathway. A striking cell death pattern involving nuclear karyorrhexis and cell pyknosis in the G1/S phase was exclusively noted when radiation was combined with apalutamide. In vivo experiments in SCID and R2G2 mice showed significantly higher efficacy of radiotherapy (2 and 4 Gy) when combined with apalutamide, resulting in extensive xenograft necrosis.. In vitro and in vivo experiments support the superiority of apalutamide over bicalutamide in combination with radiotherapy in prostate cancer. Clinical studies are encouraged to show whether replacement of bicalutamide with apalutamide may improve the curability rates.

Topics: Anilides; Animals; Cell Line, Tumor; Cell Proliferation; Cell Survival; Chemoradiotherapy; Dose-Response Relationship, Radiation; Humans; Male; Mice; Nitriles; PC-3 Cells; Prostatic Neoplasms; Radiation-Sensitizing Agents; Thiohydantoins; Tosyl Compounds; Xenograft Model Antitumor Assays

The androgen receptor (AR) is critical in the progression of prostate cancer (PCa). Small molecule antagonists that bind to the ligand binding domain (LBD) of the AR have been successful in treating PCa. However, the structural basis by which the AR antagonists manifest their therapeutic efficacy remains unclear, due to the lack of detailed structural information of the AR bound to the antagonists. We have performed accelerated molecular dynamics (aMD) simulations of LBDs bound to a set of ligands including a natural substrate (dihydrotestosterone), an agonist (RU59063) and three antagonists (bicalutamide, enzalutamide and apalutamide) as well as in the absence of ligand (apo). We show that the binding of AR antagonists at the substrate binding pocket alter the dynamic fluctuations of H12, thereby disrupting the structural integrity of the agonistic conformation of AR. Two antagonists, enzalutamide and apalutamide, induce considerable structural changes to the agonist conformation of LBD, when bound close to H12 of AR LBD. When the antagonists bind to the pocket with different orientations having close contact with H11, no significant conformational changes were observed, suggesting the AR remains in the functionally activated (agonistic) state. The simulations on a drug resistance mutant F876L bound to enzalutamide demonstrated that the mutation stabilizes the agonistic conformation of AR LBD, which compromises the efficacy of the antagonists. Principal component analysis (PCA) of the structural fluctuations shows that the binding of enzalutamide and apalutamide induce conformational fluctuations in the AR, which are markedly different from those caused by the agonist as well as another antagonist, bicalutamide. These fluctuations could only be observed with the use of aMD.

Topics: Androgen Receptor Antagonists; Androgens; Anilides; Benzamides; Binding Sites; Dihydrotestosterone; Humans; Imidazoles; Ligands; Molecular Conformation; Molecular Dynamics Simulation; Nitriles; Phenylthiohydantoin; Principal Component Analysis; Protein Binding; Protein Conformation; Receptors, Androgen; Thiohydantoins; Tosyl Compounds

Proxalutamide is a newly developed androgen receptor (AR) antagonist for the treatment of castration-resistant prostate cancer (PCa) that has entered phase III clinical trials. In the present study, we intended to elucidate the antitumor efficacy of proxalutamide through the metabolomic profiling of PCa cells. Two AR-positive PCa cell lines and two AR-negative PCa cell lines were investigated. Cell viability assays based on ATP quantitation were conducted. LC-Q/TOF-MS was used to analyze intracellular metabolites before or after the administration of proxalutamide and two other clinical AR antagonists (bicalutamide and enzalutamide). The results of this study showed that the inhibitory effect of proxalutamide on PCa cell proliferation was better than that of bicalutamide and enzalutamide, and proxalutamide preferentially affected AR-positive PCa cells over AR-negative cells. The metabolic composition of PCa cells changed significantly after proxalutamide administration, and these changes in response to proxalutamide were significantly different from those in the presence of the two other AR antagonists. In AR-positive cells, proxalutamide significantly decreased the intracellular levels of glutamine, glutamate, glutathione, cysteine, glycine, aspartate, uridine, cytidine and thymidine. However, the effects of the two other antagonists on these discriminant metabolites were ambiguous, and no changes in these metabolites were found in AR-negative cells. Our findings indicate that proxalutamide has inhibitory effects on glutamine metabolism, redox homeostasis and de novo pyrimidine synthesis in AR-positive PCa cells that enhance the cellular sensitivity to proxalutamide.

Topics: Amino Acids; Androgen Receptor Antagonists; Anilides; Benzamides; Cell Line, Tumor; Cell Survival; Glutathione; Humans; Male; Metabolome; Metabolomics; Nitriles; Nucleosides; Oxazoles; Phenylthiohydantoin; Prostatic Neoplasms, Castration-Resistant; Thiohydantoins; Tosyl Compounds

Apalutamide (ARN-509) is an antiandrogen that binds selectively to androgen receptors (AR) and does not show antagonist-to-agonist switch like bicalutamide. We compared the activity of ARN versus bicalutamide on prostate cancer cell lines. The 22Rv1, PC3, and DU145 cell lines were used to study the effect of ARN and bicalutamide on the expression cytoplasmic/nuclear kinetics of AR, AR-V7 variant, phosphorylated AR, as well as the levels of the AR downstream proteins prostate-specific antigen and TMPRSS2, under exposure to testosterone and/or hypoxia. The effects on autophagic flux (LC3A, p62, TFEB, LAMP2a, cathepsin D) and cell metabolism-related enzymes (hypoxia-inducible factor 1α/2α, BNIP3, carbonic anhydrase 9, LDHA, PDH, PDH-kinase) were also studied. The 22Rv1 cell line responded to testosterone by increasing the nuclear entry of AR, AR-V7, and phosphorylated AR and by increasing the levels of prostate-specific antigen and TMPRSS2. This effect was strongly abrogated by ARN and to a clearly lower extent by bicalutamide at 10 μmol/l, both in normoxia and in hypoxia. ARN had a stronger antiproliferative effect than bicalutamide, which was prominent in the 22Rv1 hormone-responsive cell line, and completely repressed cell proliferation at a concentration of 100 μmol/l. No effect of testosterone or of antiandrogens on autophagy flux, hypoxia-related proteins, or metabolism enzyme levels was noted. The PC3 and DU145 cell lines showed poor expression of the proteins and were not responsive to testosterone. On the basis of in-vitro studies, evidence has been reported that ARN is more potent than bicalutamide in blocking the AR pathway in normoxia and in hypoxia. This reflects a more robust, dose-dependent, repressive effect on cell proliferation.

Topics: Androgen Antagonists; Anilides; Autophagy; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Hypoxia; Male; Nitriles; Prostate-Specific Antigen; Prostatic Neoplasms; Receptors, Androgen; Testosterone; Thiohydantoins; Tosyl Compounds

Resistance of prostate cancer to castration is currently an unavoidable problem. The major mechanisms underlying such resistance are androgen receptor (AR) overexpression, androgen-independent activation of AR, and AR mutation. To address this problem, we developed an AR pure antagonist, CH5137291, with AR nuclear translocation-inhibiting activity, and compared its activity and characteristics with that of bicalutamide. Cell lines corresponding to the mechanisms of castration resistance were used: LNCaP-BC2 having AR overexpression and LNCaP-CS10 having androgen-independent AR activation. VCaP and LNCaP were used as hormone-sensitive prostate cancer cells. In vitro functional assay clearly showed that CH5137291 inhibited the nuclear translocation of wild-type ARs as well as W741C- and T877A-mutant ARs. In addition, it acted as a pure antagonist on the transcriptional activity of these types of ARs. In contrast, bicalutamide did not inhibit the nuclear translocation of these ARs, and showed a partial/full agonistic effect on the transcriptional activity. CH5137291 inhibited cell growth more strongly than bicalutamide in VCaP and LNCaP cells as well as in LNCaP-BC2 and LNCaP-CS10 cells in vitro. In xenograft models, CH5137291 strongly inhibited the tumor growth of LNCaP, LNCaP-BC2, and LNCaP-CS10, whereas bicalutamide showed a weaker effect in LNCaP and almost no effect in LNCaP-BC2 and LNCaP-CS10 xenografts. Levels of prostate-specific antigen (PSA) in plasma correlated well with the antitumor effect of both agents. CH5137291 inhibited the growth of LNCaP tumors that had become resistant to bicalutamide treatment. A docking model suggested that CH5137291 intensively collided with the M895 residue of helix 12, and therefore strongly inhibited the folding of helix 12, a cause of AR agonist activity, in wild-type and W741C-mutant ARs. In cynomolgus monkeys, the serum concentration of CH5137291 increased dose-dependently and PSA level decreased 80% at 100 mg/kg. CH5137291 is expected to offer a novel therapeutic approach against major types of castration-resistant prostate cancers.

Topics: Anilides; Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Nucleus; Cell Proliferation; Humans; Male; Mice; Molecular Docking Simulation; Mutation; Nitriles; Prostate-Specific Antigen; Prostatic Neoplasms, Castration-Resistant; Protein Transport; Receptors, Androgen; Sulfonamides; Thiohydantoins; Tosyl Compounds; Xenograft Model Antitumor Assays

Continued reliance on the androgen receptor (AR) is now understood as a core mechanism in castration-resistant prostate cancer (CRPC), the most advanced form of this disease. While established and novel AR pathway-targeting agents display clinical efficacy in metastatic CRPC, dose-limiting side effects remain problematic for all current agents. In this study, we report the discovery and development of ARN-509, a competitive AR inhibitor that is fully antagonistic to AR overexpression, a common and important feature of CRPC. ARN-509 was optimized for inhibition of AR transcriptional activity and prostate cancer cell proliferation, pharmacokinetics, and in vivo efficacy. In contrast to bicalutamide, ARN-509 lacked significant agonist activity in preclinical models of CRPC. Moreover, ARN-509 lacked inducing activity for AR nuclear localization or DNA binding. In a clinically valid murine xenograft model of human CRPC, ARN-509 showed greater efficacy than MDV3100. Maximal therapeutic response in this model was achieved at 30 mg/kg/d of ARN-509, whereas the same response required 100 mg/kg/d of MDV3100 and higher steady-state plasma concentrations. Thus, ARN-509 exhibits characteristics predicting a higher therapeutic index with a greater potential to reach maximally efficacious doses in man than current AR antagonists. Our findings offer preclinical proof of principle for ARN-509 as a promising therapeutic in both castration-sensitive and castration-resistant forms of prostate cancer.

Topics: Androgen Antagonists; Anilides; Animals; Antineoplastic Agents, Hormonal; Benzamides; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Humans; Male; Mice; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; Rats; Receptors, Androgen; Thiohydantoins; Tosyl Compounds; Xenograft Model Antitumor Assays

Castration-resistant prostate cancer (CRPC) is still dependent on androgen receptor (AR) signaling. We previously reported that a novel nonsteroidal AR pure antagonist, CH4933468, which is a thiohydantoin derivative with a sulfonamide side chain, provided in vitro proof of concept but did not in vivo.. We developed other derivatives, CH5137291, CH5138514, and CH5166623, and their pharmacological properties were compared with CH4933468 and bicalutamide. Agonist/antagonist activities in AR-mediated transactivation, cell proliferation against LNCaP and LNCaP-BC2, and AR translocation were evaluated. Agonist metabolite was monitored in liver microsomes and in pharmacokinetics experiments. Antitumor activities in CRPC xenograft models were examined using LNCaP-BC2 and VCaP-CRPC.. All CH compounds completely inhibited AR-mediated transactivation and proliferation of LNCaP and LNCaP-BC2. In contrast bicalutamide showed a partial inhibition of AR-mediated transactivation and a proliferation of LNCaP-BC2. AR translocation to nucleus was inhibited by CH compounds, but stimulated by bicalutamide. In the LNCaP-BC2 xenograft model, however, only CH5137291 showed significant inhibition of plasma PSA level and antitumor activity. The other three CH compounds were metabolized to their core structure which had agonist activity. CH5137291 also exhibited antitumor activity in a VCaP-CRPC xenograft model, but bicalutamide did not.. The molecular mechanism of the CH compounds, inhibition of AR translocation, was different from bicalutamide and this action could contribute to AR pure antagonist activity. Agonist metabolite diminished the antitumor activity of AR pure antagonist. CH5137291 exhibited antitumor activity in LNCaP-BC2 and VCaP-CRPC xenograft models, suggesting that the compound has potential for the treatment of CRPC.

Topics: Androgen Antagonists; Androgen Receptor Antagonists; Anilides; Animals; Antineoplastic Agents; Carbamates; Cell Nucleus; Cell Proliferation; Cells, Cultured; Dose-Response Relationship, Drug; Humans; Lead; Male; Mice; Mice, Nude; Mice, SCID; Neoplasm Transplantation; Nitriles; Orchiectomy; Prostatic Neoplasms; Receptors, Androgen; Sulfonamides; Thiohydantoins; Tosyl Compounds; Transcription, Genetic; Translocation, Genetic; Transplantation, Heterologous