Stabilization of p21 in PTEN-knockdown cells iseabrogated by PI3K inhibition with LY-294,002. a. Wild type ACHN cells as well as those stably transfected with PTEN-shRNA or empty vector were incubated with LY-294,002 (10 μM) for the times indicated in the presence of cycloheximide (CHX; 20 μg/ml) for the times indicated, and cell lysate was immunoblotted with antibodies against p21 or β-actin. b. A graphical representation of the data using densitometry of p21 and actin bands is reported as ratio of p21/β-actin and is normalized to the "0 CHX control" for each lane. A representative experiment is shown of three done.