Development of 5N-Bicalutamide, a High-Affinity Reversible Covalent Antiandrogen.
Felipe de Jesus Cortez1, Phuong Nguyen2, Charles Truillet3
1Department of Pharmaceutical Chemistry, University of California San Francisco , 600 16th Street, San Francisco, California 94158, United States.
ACS Chemical Biology
|October 6, 2017
Summary
A new antiandrogen, 5N-bicalutamide, forms a covalent bond with a specific cysteine residue in the androgen receptor, significantly improving efficacy and potentially overcoming resistance in advanced prostate cancer treatment.
Area of Science:
- Oncology
- Medicinal Chemistry
- Molecular Biology
Background:
- Resistance to current antiandrogens limits treatment options for advanced prostate cancer.
- Existing antiandrogens like bicalutamide face rapid resistance development.
- Strategies to improve antiandrogen efficacy beyond simple receptor affinity are needed.
Purpose of the Study:
- To develop a novel antiandrogen that overcomes resistance mechanisms.
- To design a drug that forms a covalent bond with the androgen receptor.
- To improve the binding affinity and residence time of antiandrogens.
Main Methods:
- Modification of bicalutamide to create a cysteine-reactive derivative (5N-bicalutamide).
- Assessment of binding affinity (Ki) and inhibitory concentration (IC50) of 5N-bicalutamide.
- Investigation of covalent adduct formation with androgen receptor Cys784.
Main Results:
- 5N-bicalutamide demonstrated a 150-fold increase in Ki and 20-fold increase in IC50 compared to bicalutamide.
- Covalent adduct formation with Cys784 was confirmed.
- Cys784 is not a common mutation site in prostate cancer resistance.
Conclusions:
- 5N-bicalutamide represents a promising new class of antiandrogens.
- Covalent binding to Cys784 enhances antiandrogen activity and may prevent resistance.
- This approach offers a potential strategy to overcome therapeutic resistance in advanced prostate cancer.
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