Akt regulates CXCR4 expression in PTEN-null human prostate cells. A) Cell lysate was collected from BPH-1, C4-2B, and PC3 cells. Protein levels of PTEN and β-actin were analyzed by Western blot. B) BPH-1, C4-2B, and PC3 cells were treated for 18 hours with increasing concentrations of Akt Inhibitor IV. Protein levels were analyzed by Western blot. C) C4-2B (left) and PC3 (right) cells were pretreated with or without 1 μM Akt Inhibitor IV; 2x105 cells were then plated on Matrigel coated inserts, allowed to invade for 24 hours, and stained with Crystal Violet. Total number of migrated cells was counted under 10X magnification in five fields. Assay was performed in triplicate. *: p < 0.05; **: p < 0.015.