FLTX1

FLTX1 is a fluorescent Tamoxifen derivative that can specifically label intracellular Tamoxifen-binding sites (estrogen receptors) under permeabilized and non-permeabilized conditions. FLTX1 exhibits the potent antiestrogenic properties of Tamoxifen in breast cancer cells. FLTX1 is devoid of the estrogenic agonistic effect on the uterus^[1][2]. IC50 & Target: IC50: 87.5 nM (estrogen receptor)^[1] In Vitro: FLTX1 (0.01-10 μM; 6 d) reduces MCF7 cell proliferation in a dose-dependent manner. FLTX1 (pretreated 24 h) counteracts the increase in cell growth induced by E₂ down to the vehicle level^[1].
FLTX1 (50 μM; 2 h) exhibits a dose-dependent competition with Tamoxifen (Tx) in MCF7 cells^[1].
FLTX1 (0.1 nM-100 μM; 18 h) competitively displaces the [³H] E₂ binding to rat uterine estrogen receptors (ER) rat uterus cytosol, with an IC₅₀ of 87.5 nM^[1].
FLTX1 (0.1 nM-10 μM; pretreated 8 h) reduces the estradiol-induced luciferase expression activity in a dose-dependent manner. FLTX1 (15-16 h) is devoid of the potent estrogenic agonist activity in both transiently transfected MCF7 cells and stably transfected T47D-KBluc cells^[1]. In Vivo: FLTX1 (0.01-1 mg/kg/d; s.c. for 3 d) is lacked of the estrogenic uterotrophic (and also cervical and vaginal), hyperplasic and hypertrophic effects, and failed to alter basal proliferating cell nuclear antigen immunoreactivity in mice and rats^[1].