Abstract C9: Quantitative modeling of androgen receptor-mediated transcriptional complexes in human prostate cancer cells

Abstract

Abstract The androgen receptor (AR) is a member of the nuclear receptor superfamily and the key transcription factor of androgen-mediated signaling pathways. AR translocates to the nucleus in response to ligand binding, where it selectively binds canonical androgen response elements (AREs) in DNA to assemble transcriptional complexes at target genes. Aberrant AR signaling resulting from unbalanced AR transcriptional responses at genes involved in cellular proliferation and differentiation drives the development and progression of human prostate cancers. In addition, the AR coregulator proteins, members of a large family that bind AR and modulate AR transcriptional activity, are known to elicit aberrant AR activity in prostate cancers. Although numerous AR coregulators have been identified, in most cases this was through static, binary protein-protein interaction assays (e.g., GST-fusion, yeast two-hybrid assays). Thus, to what degree androgen-sensitive coregulators mediate pathological AR actions in the context of human prostate cancer remains poorly defined. We have devised a biochemical strategy to identify and quantify androgen-sensitive coregulators (coactivators and corepressors) of AR-mediated transcription, based on their in vitro affinity for a model androgen-regulated gene promoter. Specifically, we have used DNA-affinity purification techniques in combination with label-free quantitative mass spectrometry (qMS) to do so. Our preliminary findings show that androgen-sensitive coregulators represent a functionally diverse group of protein involved in a number of signal transduction pathways. Furthermore, future studies utilizing selected reaction monitoring (SRM), a quantitative proteomics method, will be exploited to study the molecular functions of androgen-sensitive coregulators and facilitate the construction of quantitative models of AR-mediated transcription that will make it possible to predict androgenic responses at disease-associated, androgen-regulated genes. Our findings will broadly benefit the biomedical research community in that they define a novel class of androgen-sensitive coregulators and determine how they influence AR-mediated transcriptional processes underlying the development and progression of human prostate cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the Second AACR International Conference on Frontiers in Basic Cancer Research; 2011 Sep 14-18; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2011;71(18 Suppl):Abstract nr C9.