Stabilization of p21 in PTEN-knockdown cells is abrogated by Akt inhibition. a. Wild type ACHN cells as well as those stably transfected with PTEN-shPNA or empty vector were incubated with the phosphatidylinositol ether lipid analog PIA5 (10 μM), which prevents Akt activation, for the times indicated in the presence or absence of cycloheximide (CHX;20 μg/ml), and cell lysate was immunoblotted with antibodies against p21 and β-actin. b. A graphical representation of the data using densitometry of p21 and β-actin bands is reported as ratio of p21/actin and is normalized to the "0 CHX control" foreach lane. A representative experiment is shown of three done.