(E/Z)-4-hydroxy Tamoxifen-d5 is intended for use as an internal standard for the quantification of (E/Z)-4-hydroxy tamoxifen by GC- or LC-MS. (E/Z)-4-hydroxy Tamoxifen is an active metabolite of tamoxifen .1 It is formed from tamoxifen by the cytochrome P450 (CYP) isoform CYP2D6. (E/Z)-4-hydroxy Tamoxifen is cytotoxic to MCF-7 and MDA-MB-231 breast cancer cells (IC50s = 27 and 18 µM, respectively).2 It also stimulates LC3 lipidation and the formation of autophagic vesicles in MCF-7 cells in a superoxide-dependent manner.3
1.Desta, Z., Ward, B.A., Soukhova, N.V., et al.Comprehensive evaluation of tamoxifen sequential biotransformation by the human cytochrome P450 system in vitro: Prominent roles for CYP3A and CYP2D6J. Pharmacol. Exp. Ther.310(3)1062-1075(2004) 2.Seeger, H., Huober, J., Wallwiener, D., et al.Inhibition of human breast cancer cell proliferation with estradiol metabolites is as effective as with tamoxifenHorm. Metab. Res.36(5)277-280(2004) 3.Duan, L., Danzer, B., Levenson, V.V., et al.Critical roles for nitric oxide and ERK in the completion of prosurvival autophagy in 4OHTAM-treated estrogen receptor-positive breast cancer cellsCancer Lett.353(2)290-300(2014)