Androgen receptor functions in castration-resistant prostate cancer and mechanisms of resistance to new agents targeting the androgen axis

Oncogene. 2014 May 29;33(22):2815-25. doi: 10.1038/onc.2013.235. Epub 2013 Jun 10.


The metabolic functions of androgen receptor (AR) in normal prostate are circumvented in prostate cancer (PCa) to drive tumor growth, and the AR also can acquire new growth-promoting functions during PCa development and progression through genetic and epigenetic mechanisms. Androgen deprivation therapy (ADT, surgical or medical castration) is the standard treatment for metastatic PCa, but patients invariably relapse despite castrate androgen levels (castration-resistant PCa, CRPC). Early studies from many groups had shown that AR was highly expressed and transcriptionally active in CRPC, and indicated that steroids from the adrenal glands were contributing to this AR activity. More recent studies showed that CRPC cells had increased expression of enzymes mediating androgen synthesis from adrenal steroids, and could synthesize androgens de novo from cholesterol. Phase III clinical trials showing a survival advantage in CRPC for treatment with abiraterone (inhibitor of the enzyme CYP17A1 required for androgen synthesis that markedly reduces androgens and precursor steroids) and for enzalutamide (new AR antagonist) have now confirmed that AR activity driven by residual androgens makes a major contribution to CRPC, and led to the recent Food and Drug Administration approval of both agents. Unfortunately, patients treated with these agents for advanced CRPC generally relapse within a year and AR appears to be active in the relapsed tumors, but the molecular mechanisms mediating intrinsic or acquired resistance to these AR-targeted therapies remain to be defined. This review outlines AR functions that contribute to PCa development and progression, the roles of intratumoral androgen synthesis and AR structural alterations in driving AR activity in CRPC, mechanisms of action for abiraterone and enzalutamide, and possible mechanisms of resistance to these agents.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Androgen Receptor Antagonists / therapeutic use
  • Androgens / metabolism
  • Animals
  • Cell Transformation, Neoplastic / genetics
  • Cell Transformation, Neoplastic / metabolism
  • Disease Progression
  • Drug Resistance, Neoplasm*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Male
  • Prostatic Neoplasms, Castration-Resistant / drug therapy
  • Prostatic Neoplasms, Castration-Resistant / genetics
  • Prostatic Neoplasms, Castration-Resistant / metabolism*
  • Receptors, Androgen / chemistry
  • Receptors, Androgen / metabolism*
  • Repressor Proteins / metabolism
  • Steroid 17-alpha-Hydroxylase / antagonists & inhibitors
  • Steroid 17-alpha-Hydroxylase / metabolism
  • Trans-Activators / metabolism
  • Transcription, Genetic


  • Androgen Receptor Antagonists
  • Androgens
  • Receptors, Androgen
  • Repressor Proteins
  • Trans-Activators
  • CYP17A1 protein, human
  • Steroid 17-alpha-Hydroxylase