Merck, H6278-10MG, 4-Hydroxytamoxifen

General description
4-Hydroxytamoxifen (4-OHT), a first-generation selective estrogen receptor modulator (SERM), acts as an antagonist in breast cancer cells but exhibits estrogen-like effects in the uterus and bone. It is an active metabolite of the pro-drug tamoxifen (TAM), functioning as an estrogen receptor antagonist. 4-OHT binds to estrogen receptors to inhibit estradiol-induced cell proliferation without inducing cytotoxicity. It is a metabolite of the antiestrogen, tamoxifen and exhibits a higher affinity than tamoxifen and its other metabolites for binding to estrogen receptors, making it 50 to 100 times more potent in inhibiting cell proliferation in normal human breast cells and breast cancer cell lines in culture.

4-OHT effectively inhibited cell growth in the absence of estrogen when cell proliferation was stimulated by insulin or epidermal growth factor. 4-OHT inhibits lipid peroxidation within cell membranes and shows peroxyl radical scavenging activity.
Application
4-Hydroxytamoxifen has been used:

• to induce the recombination of small intestinal organoids.
• to study its impact on the ability of human peripheral blood mononuclear cells (PMNCs) to form hematopoietic colonies.
• to induce overexpression of MYCN in the neuroblastoma cell line to determine how the elevated MYCN expression influences the sensitivity of neuroblastoma cells to BIRC5/survivin inhibitor, YM155-induced apoptosis.

Biochem/physiol Actions
Metabolite of the chemotherapeutic drug tamoxifen, exhibiting more potent estrogen agonist/antagonist activity than the parent drug. Also active as intra-membranous inhibitor of lipid peroxidation.
Features and Benefits
This compound is featured on the Nuclear Receptors (Steroids) page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.
This compound was developed by AstraZeneca. To browse the list of other pharma-developed compounds and Approved Drugs/Drug Candidates, click here.