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Non-steroidal L-245,976 acts as a classical antiandrogen in vitro
J H Toney1, Y Chen, S J Rutledge
1Department of Biochemistry, Merck Research Laboratories, Rahway, NJ 07065-0900, U.S.A.
Abstract:
Non-steroidal antiandrogens have been employed in the management of prostate cancer, but the mechanism of action is unclear due to a lack of good tissue culture models. The growth of a hamster ductus deferens cell line (DDT1) is highly dependent upon the addition of 10 nM testosterone to synthetic serum-free media. We describe a non-steroidal compound N-(4-chlorophenyl)-(Z,Z)-2,3-bis(-cyclopropylmethylene) cyclopentanecarboxamide (L-245976) which antagonizes the action of testosterone on DDT1 cells at 10 microM but exhibits little or no effect on cell growth by itself. This compound also blocks the binding of 3H-dihydrotestosterone (DHT) to the human androgen receptor (AR) with an IC50 of approximately 28 microM. In addition, L-245976 was found to antagonize DHT-dependent transactivation of the AR via the probasin gene promoter at comparable doses with no agonist activity.
Insights
A novel non-steroidal antiandrogen, L-245976, effectively blocks testosterone action in a hamster ductus deferens cell line. This compound inhibits androgen receptor (AR) binding and transactivation, offering a new tool for prostate cancer research.
Area of Science:
- Pharmacology
- Molecular Biology
- Androgen Receptor Research
Background:
- Non-steroidal antiandrogens are used for prostate cancer, but their mechanisms remain unclear due to limited cell models.
- The hamster ductus deferens cell line (DDT1) requires testosterone for growth, making it a suitable model for studying androgen action.
Purpose of the Study:
- To investigate the mechanism of action of a novel non-steroidal compound, L-245976, as an antiandrogen.
- To evaluate L-245976's efficacy in antagonizing testosterone and dihydrotestosterone (DHT) activity in a relevant cell model and on the androgen receptor (AR).
Main Methods:
- Utilized the DDT1 hamster ductus deferens cell line, dependent on testosterone for growth.
- Assessed the effect of L-245976 on testosterone-induced cell growth.
- Measured the inhibition of 3H-dihydrotestosterone (DHT) binding to the human androgen receptor (AR).
- Evaluated L-245976's ability to antagonize DHT-dependent transactivation of the AR via the probasin gene promoter.
Main Results:
- L-245976 antagonized testosterone action on DDT1 cells at 10 microM without affecting cell growth independently.
- The compound inhibited 3H-DHT binding to the human AR with an IC50 of approximately 28 microM.
- L-245976 demonstrated dose-comparable antagonism of DHT-dependent AR transactivation, showing no agonist activity.
Conclusions:
- L-245976 is a potent non-steroidal antiandrogen that functions by blocking androgen receptor (AR) binding and transactivation.
- This compound represents a valuable pharmacological tool for studying androgen action and developing new prostate cancer therapies.