Discovery of substituted 3-(phenylamino)benzoic acids as potent and selective inhibitors of type 5 17β-hydroxysteroid dehydrogenase (AKR1C3)

Bioorg Med Chem Lett. 2011 Mar 1;21(5):1464-8. doi: 10.1016/j.bmcl.2011.01.010. Epub 2011 Jan 7.


Aldo-keto reductase 1C3 (AKR1C3) also known as type 5 17β-hydroxysteroid dehydrogenase has been implicated as one of the key enzymes driving the elevated intratumoral androgen levels observed in castrate resistant prostate cancer (CRPC). AKR1C3 inhibition therefore presents a rational approach to managing CRPC. Inhibitors should be selective for AKR1C3 over other AKR1C enzymes involved in androgen metabolism. We have synthesized 2-, 3-, and 4-(phenylamino)benzoic acids and identified 3-(phenylamino)benzoic acids that have nanomolar affinity and exhibit over 200-fold selectivity for AKR1C3 versus other AKR1C isoforms. The AKR1C3 inhibitory potency of the 4'-substituted 3-(phenylamino)benzoic acids shows a linear correlation with both electronic effects of substituents and the pK(a) of the carboxylic acid and secondary amine groups, which are interdependent. These compounds may be useful in treatment and/or prevention of CRPC as well as understanding the role of AKR1C3 in endocrinology.

Publication types

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

MeSH terms

  • 3-Hydroxysteroid Dehydrogenases / antagonists & inhibitors*
  • Aldo-Keto Reductase Family 1 Member C3
  • Aniline Compounds / chemical synthesis*
  • Aniline Compounds / chemistry
  • Aniline Compounds / pharmacology
  • Benzoic Acid / chemical synthesis*
  • Benzoic Acid / chemistry
  • Benzoic Acid / pharmacology
  • Drug Discovery*
  • Hydroxyprostaglandin Dehydrogenases / antagonists & inhibitors*
  • Inhibitory Concentration 50
  • Models, Biological
  • Molecular Structure


  • Aniline Compounds
  • Benzoic Acid
  • 3-Hydroxysteroid Dehydrogenases
  • Hydroxyprostaglandin Dehydrogenases
  • AKR1C3 protein, human
  • Aldo-Keto Reductase Family 1 Member C3