Inhibition of both protein synthesis and proteasomal degradation results in the identification of another mechanism of Fe depletion–mediated cyclin D1 degradation. (A-D) Effect of 311 on cyclin D1 expression in MCF-7 cells in the presence of the proteasomal inhibitor MG, and the protein synthesis inhibitor CHX. MCF-7 cells were incubated for 0.5 hours to 24 hours at 37°C with either control medium or this medium containing 311 (25 μM) in the presence of either or both MG (20 μM) and CHX (10 μg/mL). Cells were harvested, and Western blot analysis was performed. Results shown are from a representative experiment of 3 performed.