Iron chelation decreases p21^CIP1/WAF1 protein half-life. MCF-7 cells were preincubated with either control medium or medium containing 311 (25 μM) for 12 hours at 37°C and then reincubated for 20 to 480 minutes at 37°C with either control media alone (Con), 311 (25 μM), the protein synthesis inhibitor, cycloheximide (CHX; 10 μg/mL), or CHX (10 μg/mL) and 311 (25 μM). Cells were harvested and Western blot analysis was performed. (A) Western blot analysis. (B) Densitometric analysis of the results in panel A. Results are representative of 3 experiments.