1. Regulation of the glucocorticoid receptor via a BET-dependent enhancer drives antiandrogen resistance in prostate cancer.
- Author
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Shah N, Wang P, Wongvipat J, Karthaus WR, Abida W, Armenia J, Rockowitz S, Drier Y, Bernstein BE, Long HW, Freedman ML, Arora VK, Zheng D, and Sawyers CL
- Subjects
- Animals, Azepines, Benzamides, Cell Line, Tumor, Chromatin Immunoprecipitation methods, Clustered Regularly Interspaced Short Palindromic Repeats, Drug Resistance, Neoplasm drug effects, Heterografts, Humans, Male, Metabolism, Inborn Errors metabolism, Mice, Nitriles, Phenylthiohydantoin analogs & derivatives, Phenylthiohydantoin pharmacology, Receptors, Androgen metabolism, Receptors, Glucocorticoid deficiency, Sequence Analysis, Signal Transduction drug effects, Triazoles, Androgen Antagonists pharmacology, Drug Resistance, Neoplasm physiology, Gene Expression Regulation, Neoplastic, Prostatic Neoplasms pathology, Receptors, Glucocorticoid genetics, Receptors, Glucocorticoid metabolism
- Abstract
In prostate cancer, resistance to the antiandrogen enzalutamide (Enz) can occur through bypass of androgen receptor (AR) blockade by the glucocorticoid receptor (GR). In contrast to fixed genomic alterations, here we show that GR-mediated antiandrogen resistance is adaptive and reversible due to regulation of GR expression by a tissue-specific enhancer. GR expression is silenced in prostate cancer by a combination of AR binding and EZH2-mediated repression at the GR locus, but is restored in advanced prostate cancers upon reversion of both repressive signals. Remarkably, BET bromodomain inhibition resensitizes drug-resistant tumors to Enz by selectively impairing the GR signaling axis via this enhancer. In addition to revealing an underlying molecular mechanism of GR-driven drug resistance, these data suggest that inhibitors of broadly active chromatin-readers could have utility in nuanced clinical contexts of acquired drug resistance with a more favorable therapeutic index.
- Published
- 2017
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