Design and Synthesis of 4-(4-Benzoylaminophenoxy)phenol Derivatives As Androgen Receptor Antagonists

Chlorpropham, a carbamate ester herbicide, has an endocrine-disrupting potential by inhibiting the homodimerization of human androgen receptor

This study was carried out to provide the evidence with respect to the adverse potential of chlorpropham, a representative carbamate ester herbicide product, on the endocrine system by using in vitro testing methods in accordance with the Organization for Economic Cooperation and Development Test Guideline No. 458 (22Rv1/MMTV_GR-KO human androgen receptor [AR] transcriptional activation assay) and a bioluminescence resonance energy transfer-based AR homodimerization assay. Results revealed that chlorpropham had no AR agonistic effects, but it was determined to be a true AR antagonist without intrinsic toxicity against the applied cell lines. In the mechanism of chlorpropham-induced AR-mediated adverse effects, chlorpropham suppressed cytoplasmic AR translocation to the nucleus by inhibiting the homodimerization of the activated ARs. This suggests that chlorpropham exposure caused endocrine-disrupting effects through its interactions with human AR. Additionally, this study might help identify the genomic pathway of the AR-mediated endocrine-disrupting potential of N-phenyl carbamate herbicides.

Therapeutic Strategies to Target the Androgen Receptor

The androgen receptor (AR) plays a key role in the maintenance of muscle and bone and the support of male sexual-related functions, as well as in the progression of prostate cancer. Accordingly, AR-targeted therapies have been developed for the treatment of related human diseases and conditions. AR agonists are an important class of drugs in the treatment of bone loss and muscle atrophy. AR antagonists have also been developed for the treatment of prostate cancer, including metastatic castration-resistant prostate cancer (mCRPC). Additionally, selective AR degraders (SARDs) have been reported. More recently, heterobifunctional degrader molecules of AR have been developed, and four such compounds are now in clinical development for the treatment of human prostate cancer. This review attempts to summarize the different types of compounds designed to target AR and the current frontiers of research on this important therapeutic target.

Modification of [2.2]paracyclophane through cobalt-catalyzed ortho-C–H allylation and acyloxylation

The first cobalt-catalyzed ortho-C–H allylation and acyloxylation of [2,2]paracyclophanes are reported.

Diaryl Ether: A Privileged Scaffold for Drug and Agrochemical Discovery

Diaryl ether (DE) is a functional scaffold existing widely both in natural products (NPs) and synthetic organic compounds. Statistically, DE is the second most popular and enduring scaffold within the numerous medicinal chemistry and agrochemical reports. Given its unique physicochemical properties and potential biological activities, DE nucleus is recognized as a fundamental element of medicinal and agrochemical agents aimed at different biological targets. Its drug-like derivatives have been extensively synthesized with interesting biological features including anticancer, anti-inflammatory, antiviral, antibacterial, antimalarial, herbicidal, fungicidal, insecticidal, and so on. In this review, we highlight the medicinal and agrochemical versatility of the DE motif according to the published information in the past decade and comprehensively give a summary of the target recognition, structure-activity relationship (SAR), and mechanism of action of its analogues. It is expected that this profile may provide valuable guidance for the discovery of new active ingredients both in drug and pesticide research.

Development of Androgen-Antagonistic Coumarinamides with a Unique Aromatic Folded Pharmacophore

First-generation nonsteroidal androgen receptor (AR) antagonists, such as flutamide (2a) and bicalutamide (3), are effective for most prostate cancer patients, but resistance often appears after several years due to the mutation of AR. Second-generation AR antagonists are effective against some of these castration-resistant prostate cancers, but their structural variety is still limited. In this study, we designed and synthesized 4-methyl-7-(N-alkyl-arylcarboxamido)coumarins as AR antagonist candidates and evaluated their growth-inhibitory activity toward androgen-dependent SC-3 cells. Coumarinamides with a secondary amide bond did not show inhibitory activity, but their N-methylated derivatives exhibited AR-antagonistic activity. Especially, 19b and 31b were more potent than the lead compound 7b, which was comparable to hydroxyflutamide (2b). Conformational analysis showed that the inactive coumarinamides with a secondary amide bond have an extended structure with a trans-amide bond, while the active N-methylated coumarinamides have a folded structure with a cis-amide bond, in which the two aromatic rings are placed face-to-face. Docking study suggested that this folded structure is important for binding to AR. Selected coumarinamide derivatives showed AR-antagonistic activity toward LNCaP cells with T877A AR, and they had weak progesterone receptor (PR)-antagonistic activity. The folded coumarinamide structure appears to be a unique pharmacophore, different from those of conventional AR antagonists.

The design, synthesis and anti-tumor mechanism study of new androgen receptor degrader

Targeted protein degradation using small molecules is a novel strategy for drug development. In order to solve the problem of drug resistance in the treatment of prostate cancer, proteolysis-targeting chimeras (PROTAC) was introduced into the design of anti-prostate cancer derivatives. In this work, we synthesized two series of selective androgen receptor degraders (SARDs) containing the hydrophobic degrons with different linker, and then investigated the structure-activity relationships of these hybrid compounds. Most of the synthesized compounds exhibited moderate to good activity against all the cancer cell lines selected. Among them, compound A9 displayed potent inhibitory activity against LNCaP prostate cancer cell line with IC₅₀ values of 1.75 μM, as well as excellent AR degradation activity. Primary mechanism studies elucidated compound A9 arrested cell cycle at G0/G1 phase and induced a mild apoptotic response in LNCaP cells. Further study indicated that the degradation of AR was mediated through proteasome-mediated process. For all these reasons, compound A9 held promising potential as anti-proliferative agent for the development of highly efficient SARDs for drug-resistance prostate cancer therapies.

In Silico Molecular Docking, Synthesis of 4-(4-benzoylaminophenoxy) Phenol Derivatives as Androgen Receptor Antagonists

AIM AND OBJECTIVE

To study the structural difference, optimization, molecular docking and development of new benzoyl amino phenoxy phenol derivatives as anti-prostate cancer agents.

MATERIALS AND METHODS

Strategies towards the identification of novel benzoyl amino phenoxy phenol (BAPP), molecular docking was performed with the designed Androgen Receptor (AR) blockers. Pharmacophore-based studies revealed that the nitro- or cyano-substituted anilide groups have influenced the activity profiles of non-steroidal AR antagonists, followed by the molecular docking studies with five AR receptors. Molecular docking studies were carried out using Maestro from Schrödinger. Absorption, Distribution, Metabolism, and Excretion (ADME) properties of the BAPP derivatives were evaluated for the predictive bioavailability/drug-likeness. These studies supported vital information for designing new anti-prostate cancer agents.

RESULTS AND DISCUSSION

There are 125 compounds were screened and best fit compounds (12 entries) were well-synthesized in good to excellent yields and anticancer activities were evaluated. The compounds, 6i showed the highest activities of this series (14.65 ± 1.35 µM).

CONCLUSION

The present approach is simple and efficient for the synthesis of BAPP derivatives and the observed IC50 values of BAPPs were in good agreement with the glide scores obtained from the molecular docking. We, further, intend to carry out in vitro and in vivo AR binding studies for the active compounds.

Androgen receptor modulators: a review of recent patents and reports (2012-2018)

INTRODUCTION

Androgen receptor (AR) is one of the most promising targets of drug discovery because of its importance in male reproductive systems and homeostasis of bone and muscle. Various AR-modulating agents have been developed and used clinically to treat androgen-dependent disorders, including prostate cancer, and some new-generation antiandrogens have recently been approved. Intensive studies are underway to develop various AR-modulating compounds, including conventional antagonists, tissue-specific AR modulators (SARMs), degraders, and nonconventional AR-modulating compounds that target sites other than the ligand-binding domain (LBD), such as the N-terminal domain (NTD) or the DNA-binding domain (DBD).

AREAS COVERED

The authors provide an overview of AR-modulating agents from 2012 to 2018.

EXPERT OPINION

The LBD has been the primary target for AR modulation, and important AR-modulating agents, including SARMs and recently approved antiandrogens such as enzalutamide and apalutamide, have been developed as conventional LBD antagonists. Development of LBD-targeting antiandrogens to treat prostate cancer is a kind of cat-and-mouse game between clinical agents and AR mutations, and therefore next-generation antiandrogens are still required. Development of nonconventional AR-modulating agents targeting NTD and DBD, is likely to be a promising approach to develop multiple and synergistic strategies able to overcome any kind of androgen-dependent condition.

Exploring the Interaction Mechanism Between Cyclopeptide DC3 and Androgen Receptor Using Molecular Dynamics Simulations and Free Energy Calculations

Androgen receptor (AR) is a key target in the discovery of anti-PCa (Prostate Cancer) drugs. Recently, a novel cyclopeptide Diffusa Cyclotide-3 (DC3), isolated from Hedyotisdiffusa, has been experimentally demonstrated to inhibit the survival and growth of LNCap cells, which typically express T877A-mutated AR, the most frequently detected point mutation of AR in castration-resistant prostate cancer (CRPC). But the interaction mechanism between DC3 and AR is not clear. Here in this study we aim to explore the possible binding mode of DC3 to T877A-mutated AR from molecular perspective. Firstly, homology modeling was employed to construct the three-dimensional structure of the cyclopeptide DC3 using 2kux.1.A as the template. Then molecular docking, molecular dynamics (MD) simulations, and molecular mechanics/generalized Born surface area (MM-GBSA) methods were performed to determine the bind site and explore the detailed interaction mechanism of DC3-AR complex. The obtained results suggested that the site formed by H11, loop888-893, and H12 (site 2) was the most possible position of DC3 binding to AR. Besides, hydrogen bonds, hydrophobic, and electrostatic interactions play dominant roles in the recognition and combination of DC3-AR complex. The essential residues dominant in each interaction were specifically revealed. This work facilitates our understanding of the interaction mechanism of DC3 binding to AR at the molecular level and contributes to the rational cyclopeptide drug design for prostate cancer.

Development of nonsteroidal glucocorticoid receptor modulators based on N-benzyl-N-(4-phenoxyphenyl)benzenesulfonamide scaffold

N-Benzyl-N-(4-phenoxyphenyl)benzenesulfonamide derivatives were developed as a novel class of nonsteroidal glucocorticoid receptor (GR) modulators, which are promising drug candidates for treating immune-related disorders. Focusing on the similarity of the GR and progesterone receptor (PR) ligand-binding domain (LBD) structures, we adopted our recently developed PR antagonist 10 as a lead compound and synthesized a series of derivatives. We found that the N-(4-phenoxyphenyl)benzenesulfonamide skeleton serves as a versatile scaffold for GR antagonists. Among them, 4-cyano derivative 14m was the most potent, with an IC₅₀ value of 1.43μM for GR. This compound showed good selectivity for GR; it retained relatively weak antagonistic activity toward PR (IC₅₀ for PR: 8.00μM; 250-fold less potent than 10), but showed no activity toward AR, ERα or ERβ. Interestingly, the 4-amino derivative 15a exhibited transrepression activity toward NF-κB in addition to GR-antagonistic activity, whereas 14m did not. The structure-activity relationship for transrepression was different from that for GR-antagonistic activity. Computational docking simulations suggested that 15a might bind to the ligand-binding pocket of GR in a different manner from 14m. These findings open up new possibilities for developing novel nonsteroidal GR modulators with distinctive activity profiles.

Rational design and synthesis of novel phenylsulfonyl-benzamides as anti-prostate cancer agents

A novel antiproliferative molecular scaffold was designed by rational modification of known antiandrogens, achieving a significant improvement in anti-cancer activity.

Prostate cancer is a major cause of male death worldwide and the identification of new efficient treatments is constantly needed. Different non-steroidal androgen receptor antagonists are approved also in the case of castration-resistant cancer forms. Using a rational approach and molecular modelling studies to modify the structure of antiandrogen drug bicalutamide, a new series of phenylsulfonyl-benzamide derivatives was designed and synthesised. Their antiproliferative activities were evaluated in four different human prostate cancer cell lines and several new compounds showed significantly improved IC₅₀ values in the low μM range. The cytotoxicity profile was also evaluated for the novel structures in the HEK293 cell line.

Development of N-(4-Phenoxyphenyl)benzenesulfonamide Derivatives as Novel Nonsteroidal Progesterone Receptor Antagonists

We report here development of N-(4-phenoxyphenyl)benzenesulfonamide derivatives as a novel class of nonsteroidal progesterone receptor (PR) antagonists. PR plays key roles in various physiological systems, including the female reproductive system, and PR antagonists are candidates for clinical treatment of multiple diseases, including uterine leiomyoma, endometriosis, breast cancer, and some psychiatric disorders. We found that the benzenesulfonanilide skeleton functions as a novel scaffold for PR antagonists, and we adopted 3-chlorobenzenesulfonyl derivative 20a as a lead compound for structural development. Among the synthesized compounds, 3-trifluoromethyl derivative 32 exhibited the most potent PR-antagonistic activity, with high binding affinity for PR and selectivity over androgen receptor (AR). It is structurally distinct from other nonsteroidal PR antagonists, including cyanopyrrole derivatives, and further modification is expected to afford novel selective PR modulators.

Recent Developments in Androgen Receptor Antagonists

The androgen receptor (AR), a ligand-dependent transcription factor that regulates the expression of a series of downstream target genes after the binding of androgens, has been a target for the discovery of drugs used to treat prostate cancer. Prostate cancer always progresses to castration-resistant prostate cancer after a period of androgen deprivation therapy. Thus, developing potent androgen receptor antagonists for the therapy of castration-resistant prostate cancer possesses great significance. This review summarizes the preclinical development of androgen receptor antagonists, conventional androgen receptor antagonists that competitively bind to the ligand binding domain of the androgen receptor and coactivator antagonists of the androgen receptor, including both activation function-2 antagonists and binding function-3 antagonists. We hope that this review can help other researchers find new scaffolds and sites for the treatment of prostate cancer.