Activation of PKR Inhibits Cell Migration Figure 1. Activation of PKR inhibits the motility of breast cancer cells. A: MDA-MB231 cells (5x104) were placed into the upper compartments of migration chambers (transwells) in the presence of PIC (0, 5 and 10 ng/ml). The transwells were incubated at 37uC in 5% CO2 overnight. The number of migrated MDA-MB231 cells was measured as described under the Materials and Methods. B: The number of migrated BT474 and SKBR3 cells in the presence of PIC treatment (0 or 10 ng/ml) was determined as described above. C: The expression of phosphorylated PKR and total PKR in MCF7, MB231, BT474 and SKRB3 cells were determined by immunoblotting. D: MDA-MB231 cells were exposed to PIC (0, 5 and PLOS ONE | www.plosone.org 3 October 2012 | Volume 7 | Issue 10 | e47721