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  2. Elevated labile iron in castration-resistant prostate cancer is targetable with ferrous iron-activatable antiandrogen therapy

Elevated labile iron in castration-resistant prostate cancer is targetable with ferrous iron-activatable antiandrogen therapy

  • Eur J Med Chem. 2023 Jan 14;249:115110. doi: 10.1016/j.ejmech.2023.115110.
Ryan L Gonciarz 1 Sasank Sakhamuri 2 Nima Hooshdaran 2 Garima Kumar 2 Hyunjung Kim 2 Michael J Evans 3 Adam R Renslo 4
Affiliations

Affiliations

  • 1 Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, 94158, United States.
  • 2 Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, 94158, United States.
  • 3 Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, 94158, United States; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, 94158, United States. Electronic address: michael.evans@ucsf.edu.
  • 4 Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, 94158, United States; Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, 94158, United States. Electronic address: adam.renslo@ucsf.edu.
Abstract

Clinical responses to second generation androgen signaling inhibitors (e.g., enzalutamide) in metastatic castration-resistant prostate Cancer (mCRPC) are variable and transient, and are associated with dose limiting toxicities, including rare but severe CNS effects. We hypothesized that changes to iron metabolism coincident with more advanced disease might be leveraged for tumor-selective delivery of antiandrogen therapy. Using the recently described chemical probes SiRhoNox and 18F-TRX in mCRPC models, we found elevated Fe2+ to be a common feature of mCRPC in vitro and in vivo. We next synthesized ferrous-iron activatable drug conjugates of second and third-generation antiandrogens and found these conjugates possessed comparable or enhanced antiproliferative activity across mCRPC cell line models. Mouse pharmacokinetic studies showed that these prototype antiandrogen conjugates are stable in vivo and limited exposure to conjugate or free antiandrogen in the brain. Our results reveal elevated Fe2+ to be a feature of mCRPC that might be leveraged to improve the tolerability and efficacy of antiandrogen therapy.

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