Fk866

All cell lines were obtained from American Type Culture Collection (ATCC) (Manassas, VA, USA). An MTT assay kit was purchased from Promega Corporation (Fitchburg, WI, USA). FK866 was purchased from Enzo Life Sciences (Farmingdale, NY, USA). T47D and MCF-7 cells were maintained in DMEM containing 350 μL/L gentamicin and 25 mL/L fetal bovine serum. 184A1 cells were maintained in HuMEC media containing 175 μL/L gentamicin, HuMEC supplement, and bovine pituitary extract. The cells were grown to confluency in either T-12.5 or T-25 cm² tissue culture flasks using an incubator maintained at 5% CO₂ humid atmosphere at 37°C. The MTT assay34 (link),35 (link) was carried out as follows: T47D, MCF-7, and 184A1 cells were plated in 96-well plates at a density of 10,000 cells/well for overnight at 37°C. The cells were then treated with different concentrations of the test agent and incubated for 72 h. The MTT reagent was added to the cells for 4 h for developing formazan crystals. Following this, solubilization buffer was added to the wells and the absorbance was measured at 570 nm. Each experiment was repeated four times, and the standard deviations are reported.