PRL partially restores total LKB1 and phosphorylated AMPKα protein levels in breast cancer cells in which LKB1 is transiently knocked down. A) Representative Western blots depicting PRL-mediated changes in total LKB1 protein levels and the corresponding changes in phosphorylated AMPKα (pAMPKα) in 184B5, MCF-7, and MDA-MB-231 cells in which LKB1 was transiently knocked down. B) Densitometry revealed that PRL induced a 2-fold increase in the level of total LKB1 protein in MDA-MB-231 cells. No changes were observed in 184B5 cells that underwent a similar treatment. Increased levels of pAMPKα were also observed in MCF-7 and MDA-MB-231 cells (1.4- and 1.9-fold relative to untreated, respectively) in response to PRL. Different letters represent statistical differences between groups, with ' and " indicate changes within a cell type. Vehicle = V and LKB1 siRNA = L. Results represent the mean ± SEM of three independent experiments.