Biological Activity
Endoxifen Z-isomer is the most important Tamoxifen metabolite responsible for eliciting the anti-estrogenic effects of this drug in breast cancer cells expressing estrogen receptor-alpha (ERα). Endoxifen inhibits hERG tail currents at 50 mV in a concentration-dependent manner with IC50 values of 1.6 μM.Estrogen Receptor/ERREndoxifen Z-isomer is considered a prodrug, since it has a much higher potency for the estrogen receptor than its parent drug. Endoxifen inhibits the hERG channel protein trafficking to the plasma membrane in a concentration-dependent manner with Endoxifen being more potent than Tamoxifen. [1] Endoxifen is also shown to be a more potent inhibitor of estrogen target genes when ERβ is expressed. Additionally, low concentrations of Endoxifen Z-isomer observed in Tamoxifen treated patients with deficient CYP2D6 activity (20 to 40 nM) markedly inhibit estrogen-induced cell proliferation rates in the presence of ERβ, whereas much higher Endoxifen Z-isomer concentrations are needed when ERβ is absent.[2]
In Vitro
No in vitro data are provided in the current product source. Contact us for further information.
In Vivo
No in vivo data are provided in the current product source. Contact us for further information.
Target
hERG Potassium Channel IC50 value: 1.6 μM [1]
References & source
[1]. Chae YJ, et al. Endoxifen, the active metabolite of tamoxifen, inhibits cloned hERG potassium channels. Eur J Pharmacol. 2015 Apr 5;752:1-7.
[2]. Wu X, et al. Estrogen receptor-beta sensitizes breast cancer cells to the anti-estrogenic actions of endoxifen. Breast Cancer Res. 2011 Mar 10;13(2):R27.
Published experimental findings depend on the model and assay conditions. They do not guarantee equivalent performance in every application. For laboratory research use only.
