Abstract 79: An androgen response element-based reporter assay for the detection of androgen receptor activity in prostate cells

Abstract

Abstract Background: The androgen receptor (AR) transcription factor plays pivotal roles in the development and progression of prostate cancer. AR is activated and maintained throughout prostate cancer progression even in castration-resistant prostate cancer (CRPC). AR and its classical target genes such as PSA (KLK3) are, however, efficiently shut off in basal epithelial prostate cells and possibly in prostate cancer stem cells (CSCs). There is limited information on the mechanisms that keep the AR OFF in these cells, and the conditions that turn the AR and target genes ON. Results: Fluorescent and luminescent reporters were constructed to develop a functional assay for AR activity. These reporters contain the repeated AR binding promoter sequences and were designed in a way that the AR can activate these AR element (ARE) reporters. The 241B reporter was selected among the constructed ARE reporters on the basis of higher activity. The AR positive prostate cancer cell line, LNCaP, was transduced with the lentiviral 241B-mCherry fluorescence reporter. FACS analysis quantitated the ARE reporter activity when reporter cells were treated with androgen and with the AR antagonist, enzalutamide, or the anti-androgen, abiraterone. AR expression vectors were also constructed with the AR open reading frames cloned into lentiviral expression vectors. All constructs were sequenced to verify the correct AR DNA sequence and their activity were tested using ARE reporter system. Conclusion: The developed ARE reporter system is useful to understand the mechanisms of AR and AR target gene activation in different subpopulations of prostate cancer cells. It will help us to investigate the role of the AR in differentiation and proliferation of prostate cells and to study the AR activity in two and three dimensional cell cultures. This system can also be useful in screening for drugs with activity against the AR. Citation Format: Waqas Azeem, Margrete R. Hellem, Jan R. Olsen, Yaping Hua, Kristo Marvyin, Lisha Li, Yi Qu, Biaoyang Lin, Xisong Ke, Anne M. Oyan, Karl-Henning Kalland. An androgen response element-based reporter assay for the detection of androgen receptor activity in prostate cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 79. doi:10.1158/1538-7445.AM2015-79