The effect of Fe chelators or Fe complexes on Ndrg1 protein levels in MCF-7 cells. (A) High concentrations of DFO (100-150 μM) were required to markedly increase Ndrg1 protein levels. (B) Concentrations of 311 of only 2.5 μM or more were required to increase Ndrg1 protein levels. (C) Membrane-permeable chelators such as DFO, 311, Dp44mT, and L1 increase Ndrg1 protein levels. (D) Only Fe chelators that show high-antiproliferative activity and Fe chelation efficacy increase Ndrg1 protein levels when examined at 25 μM. MCF-7 cells were incubated for 24 hours at 37°C with the chelators or Fe complexes, and the expression of Ndrg1 and β-actin protein levels was assessed by Western blotting (see “Materials and methods” for details). Results show a typical experiment from 3 performed.