Effects of 4OHT on the growth of MDA-MB-231 cells. (A) Concentration- and time-dependent effects of 4OHT on the growth of MDA-MB-231 cells. The cells were plated in 96-well plates and treated with different concentrations of 4-OHT. After the indicated times, the viability of the cells was evaluated using the XTT assay. The absorbance reading at 450 nm was proportional to cell viability. The differences in cell growth after 72 h were statistically significant (P < 0.05) at all the studied 4OHT concentrations when compared to untreated controls (CN). (B) The migratory ability of MDA-MB-231 cells treated with vehicle (control; CN) or with 1 μM 4OHT was analysed using a wound healing assay. (C) The effects of U0126 (10 μM) and fulvestrant (10 μM) on the growth of MDA-MB-231 cells treated with vehicle (control; CN) or with 1 μM 4OHT.