Anna C. Groner^1,2, Jonas de Tribolet-Hardy^1,2, Tiziano Bernasocchi³, Laura Cato^1,2, Diana Melchers⁴, René Houtman⁴, Andrew C. B. Cato⁵, Patrick Tschopp⁶, Lei Gu⁷, Andrea Corsinotti⁸, Qing Zhong⁹, Christian Fankhauser⁹, Christine Fritz⁹, Cédric Poyet¹⁰, Levi A. Garraway^1,11,12, Peter J. Wild⁹, Jean-Philippe Theurillat^3,11,13 and Myles Brown^1,2

¹Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA

² Center for Functional Cancer Epigenetics, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA

³ Institute of Oncology Research, Bellinzona, TI 6500, Switzerland

⁴ PamGene International, Den Bosch, 521HH, The Netherlands

⁵ Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany

⁶ Department of Genetics, Harvard Medical School, Boston, MA 02215, USA

⁷ Division of Newborn Medicine, Children’s Hospital Boston and Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA

⁸ MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, Edinburgh EH16 4UU, Scotland, UK

⁹ Institute of Surgical Pathology, University Hospital Zurich, Zurich, ZH 8091, Switzerland

¹⁰ Department of Urology, University Hospital Zurich, Zurich, ZH 8091, Switzerland

¹¹ The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA

¹² Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA

¹³ Centre Hospitalier Universitaire Vaudois, University of Lausanne, Lausanne, VD 1011, Switzerland

Androgen receptor (AR) signaling is a key driver of prostate cancer (PC). While androgen-deprivation therapy is effective in patients with advanced disease, tumors progress to lethal castration-resistant disease (CRPC). We show that recurrent PC-driver mutations in SPOP up-regulate the TRIM24 protein, which promotes proliferation under low androgen conditions. TRIM24 augments AR signaling, and AR and TRIM24 co-activated genes are significantly up-regulated in CRPC. Expression of TRIM24 protein increases from primary PC to CRPC, and both TRIM24 protein levels and the AR/TRIM24 gene signature predict disease-recurrence. Analyses in CRPC cells reveal that the TRIM24 bromodomain and the AR-interacting motif are essential to support proliferation. These data provide a rational for therapeutic TRIM24 targeting in SPOP-mutant and CRPC patients.