Reconstitution of p21^CIP1/WAF1 protein expression after Fe chelation with the Fe supplement FAC. MCF-7 cells were preincubated with control medium (Con) or 311 (25 μM) for 24 hours at 37°C. Medium was then removed, and the cells were reincubated with either control medium (Con), FAC (100 μg/mL), 311 (25 μM), or 311 (25 μM) and FAC (100 μg/mL) for 0, 4, 8, 20, and 24 hours at 37°C. Cells were then harvested, total protein was extracted, and Western blot was performed to measure p21^CIP1/WAF1 protein expression. Results are typical of 3 independent experiments.