Androgen receptor antagonism drives cytochrome P450 17A1 inhibitor efficacy in prostate cancer.

Journal Article (Journal Article)

The clinical utility of inhibiting cytochrome P450 17A1 (CYP17), a cytochrome p450 enzyme that is required for the production of androgens, has been exemplified by the approval of abiraterone for the treatment of castration-resistant prostate cancer (CRPC). Recently, however, it has been reported that CYP17 inhibitors can interact directly with the androgen receptor (AR). A phase I study recently reported that seviteronel, a CYP17 lyase-selective inhibitor, ædemonstrated a sustained reduction in prostate-specific antigen in a patient with CRPC, and another study showed seviteronel's direct effects on AR function. This suggested that seviteronel may have therapeutically relevant activities in addition to its ability to inhibit androgen production. Here, we have demonstrated that CYP17 inhibitors, with the exception of orteronel, can function as competitive AR antagonists. Conformational profiling revealed that the CYP17 inhibitor-bound AR adopted a conformation that resembled the unliganded AR (apo-AR), precluding nuclear localization and DNA binding. Further, we observed that seviteronel and abiraterone inhibited the growth of tumor xenografts expressing the clinically relevant mutation AR-F876L and that this activity could be attributed entirely to competitive AR antagonism. The results of this study suggest that the ability of CYP17 inhibitors to directly antagonize the AR may contribute to their clinical efficacy in CRPC.

Full Text

Duke Authors

Cited Authors

  • Norris, JD; Ellison, SJ; Baker, JG; Stagg, DB; Wardell, SE; Park, S; Alley, HM; Baldi, RM; Yllanes, A; Andreano, KJ; Stice, JP; Lawrence, SA; Eisner, JR; Price, DK; Moore, WR; Figg, WD; McDonnell, DP

Published Date

  • June 1, 2017

Published In

Volume / Issue

  • 127 / 6

Start / End Page

  • 2326 - 2338

PubMed ID

  • 28463227

Pubmed Central ID

  • PMC5451248

Electronic International Standard Serial Number (EISSN)

  • 1558-8238

Digital Object Identifier (DOI)

  • 10.1172/JCI87328


  • eng

Conference Location

  • United States