PMC

A. In vitro antiestrogen response of ERα knockdown in MCF7S cells. % Relative Cell Number represents viable cell number in antiestrogen-treated samples relative to vehicle-treated control. Data for two individual clones were generated from three independent experiments. Error bars represent S.E.M. B. Sphere formation frequency of antiestrogen treated ERα knockdown MCF7S cells. Three independent experiments were performed for two individual clones. Error bars: S.E.M.

Effects of drugs on epithelial cell viability (absorbance). Denosumab (D) (25 μg/mL) is indicated in red. Additive exposures of antiestrogen (AE) or corticosteroid (GLU) are indicated in black and blue, respectively

A. Cell proliferation of MCF7S in the presence of antiestrogens. Cell proliferation of MCF7S treated with 4-OHT (top) or ICI (bottom) from four independent experiments. Error bars represent standard error of the mean (S.E.M.). B. Sphere formation of MCF7S after antiestrogen challenge with 4-OHT or ICI. (Top) Sphere formation frequency of 4-OHT-(top) or ICI-(bottom) treated MCF7S from four independent experiments. Plating efficiency was calculated as number of sphere >50 microns in diameter/total number of cells seeded ×100%. Error bars represent S.E.M. C. In vivo tumorigenic assay for MCF7S cells following antiestrogen challenge. MCF7S were either untreated, treated with 2.5 µM 4-OHT or 1 µM ICI for 4 days then recovered for 6 days in culture without antiestrogens, prior to injections. At least 4 mice were injected for each condition.