Differential Presentation of Protein Interaction Surfaces on the Androgen Receptor Defines the Pharmacological Actions of Bound Ligands

Abstract

Summary The pharmacological activity of different nuclear receptor (NR) ligands is reflected by their impact on receptor structure. Thus, we asked whether differential presentation of protein-protein interaction surfaces on the androgen receptor (AR), a surrogate assay of receptor conformation, could be used in a prospective manner to define the pharmacological activity of bound ligands. To this end, we identified over 150 proteins/polypeptides whose ability to interact with AR is influenced in a differential manner by ligand binding. The most discriminatory of these protein-AR interactions were used to develop a robust compound-profiling tool that enabled the separation of ligands into functionally distinguishable classes. Importantly, the ligands within each class exhibited similar pharmacological activities, a result that highlights the relationship between receptor structure and activity and provides direction for the discovery of novel AR modulators.

Androgen receptor antagonism drives cytochrome P450 17A1 inhibitor efficacy in prostate cancer

“…HepG2 cells were maintained in Basal Medium Eagle (Sigma Aldrich) containing 8% FBS. For mammalian 2-hybrid-based AR cofactor assays (41,42), cells were seeded in 96-well plates and transfected with VP16-AR (900 ng), 5XGalLuc3 (900 ng), Gal4-interactor (900 ng), and Renilla-Luc (300 ng) using Lipofectin (Thermo Fisher Scientific). Cells were then treated with the ligands as indicated in Figure legend 3 for 48 hours, at which point, dual-luciferase assays were performed.…”

“…Previously, we reported on the development and validation of a cell-based AR conformationprofiling tool that utilizes peptide probes derived from nuclear receptor coregulators to survey ligand-induced alterations on the surface of the receptor (41,42). This tool leverages the observation that receptor conformation, a primary determinant of coregulator recruitment, is predictive of the pharmacological activity of AR ligands.…”

A genome-wide RNA interference screen identifies new regulators of androgen receptor function in prostate cancer cells

“…In fact, improved therapy of CRPC could result from targeting cellular factors that control AR activity (Nabhan et al 2011). Although the role of the AR in prostate health and disease has been illuminated by highthroughput genomic Sharma et al 2013), metabolomic (Sreekumar et al 2009), and chemical-biology approaches (Norris et al 2009), systematic profiling of the genes that functionally regulate AR action has not been conducted.…”

New Approaches Targeting Androgen Receptor Signal Pathways for Treatment of Castration-Resistant Prostate Cancer

“…The failure of hormonal therapy for prostate cancer has been largely attributed to overexpression of AR in recurrence of the cancer (Chi et al, 2009;Joseph et al, 2009;Norris et al, 2009;Singh et al, 2008;Tran et al, 2009;Zhou et al, 2008). Development of more effective hormonal therapeutic agents targeting overexpressed AR becomes an important research area.…”

“…Many AR antagonists previously developed are mainly ligand competitors for androgens and can not overcome the over-expressed AR in CRPC. Newer approaches have been used to develop agents that can target potential sites in the AR to abrogate the function of the mutated or over-expressed receptor in cancer cells (Chi et al, 2009;Joseph et al, 2009;Norris et al, 2009;Singh et al, 2008;Tran et al, 2009;Zhou et al, 2008;Shen & Balk, 2009). For example, it was reported that a conformation-based assay was used to screen a diverse small molecule library of ≈10,000 compounds in order to select chemicals that can inhibit the AR-gelsolin interaction .…”