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[Update on the mechanism of action of synthetic antiestrogens]
P Briozzo1, F Vignon, H Rochefort
1Unité Hormones et Cancer, INSERUM U 148, Montpellier.
Abstract:
Synthetic antiestrogens are drugs commonly used in the endocrine therapy of breast cancer. Their pharmacology is complex, most of them presenting a partial estrogenic effect. Their action via the estrogen receptor (ER) has been better understood through the use of cellular models. The antihormone-ER complex binds to estrogen responsive elements on DNA, but is unable to mimic exactly the transcriptional activation induced by the estradiol-ER complex. The antiproliferative effect of these antihormones, mainly cystostatic but also cytotoxic, is the result of the competitive inhibition of estrogens, and might also involve interaction with other cellular mediators (stimulation of inhibitory factors, and growth factors inhibition). The term antiestrogen seems therefore to be too restrictive and it may be more accurate to name them estrogen-receptor mediated drugs inhibiting cell proliferation.
Insights
Synthetic antiestrogens, used in breast cancer endocrine therapy, exhibit complex pharmacology with partial estrogenic effects. Their antiproliferative action involves estrogen receptor (ER) binding and inhibition of estrogenic activity.
Area of Science:
- Pharmacology
- Molecular Biology
- Oncology
Context:
- Synthetic antiestrogens are crucial in endocrine therapy for breast cancer.
- Their complex pharmacology includes partial estrogenic effects.
- Cellular models have elucidated their action via the estrogen receptor (ER).
Purpose:
- To clarify the complex pharmacology of synthetic antiestrogens.
- To explain their mechanism of action at the estrogen receptor (ER) and DNA level.
- To propose a more accurate nomenclature for these drugs.
Summary:
- Synthetic antiestrogens bind to the estrogen receptor (ER), forming a complex that interacts with DNA's estrogen-responsive elements.
- This complex fails to fully replicate the transcriptional activation caused by estradiol-ER complexes.
- Their antiproliferative effects (cytostatic and cytotoxic) stem from competitive inhibition of estrogens and potentially other cellular interactions.
Impact:
- Understanding antiestrogen mechanisms refines breast cancer treatment strategies.
- Accurate drug classification aids in predicting therapeutic efficacy and side effects.
- This research supports the development of targeted endocrine therapies.