Abstract A057: Small Molecule Microarray Screening Identifies Novel Androgen Receptor Ligands

The androgen receptor (AR) is a well-established oncogenic driver of prostate cancer, and AR-targeting hormone therapy has proven an efficacious treatment option for patients with metastatic prostate cancer. Due to the importance of AR in prostate cancer disease progression, we leveraged small molecule microarray (SMM) screening technology to identify compounds that bind to transcriptional complexes of a common AR splice-variant, AR-V7, present along with AR in castration-resistant prostate cancer cell lysates. A subset of SMM hits were identified to modulate the AR Transcription Regulatory Network (TRN) in hormone-sensitive, but not castration-resistant prostate cancer models using a functional cell-based transcription signature approach. Several AR SMM hits directly engaged the AR ligand binding domain in a biophysical assay. One of these AR SMM hits altered AR nuclear translocation and antagonized steroid receptor co-activator recruitment to AR but did not antagonize the glucocorticoid receptor. Leveraging structural data for known AR ligands, we propose a computational model for binding of this molecule to the known AR ligand binding domain. Together, the data demonstrates that the AR SMM lysate screen successfully identified structurally novel small molecules that modulate the AR TRN and bind the AR ligand binding domain. Citation Format: Marek J Kobylarz, Michelle G Shum, Wayne L Glore, Ava Saffren, Shannon Carpenter, Mulini Pingili, Andrew Clay, Tamara D Hopkins, Hua Gao, Anna C Schinzel, Marius S Pop, Nikolaus D Obholzer, David B Freeman, Christopher J Dinsmore, Benjamin W Trotter, Charles Y Lin, Peter B Rahl. Small molecule microarray screening identifies novel androgen receptor ligands [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A057.