Fig. 4

PTEN contributes to the survival of low p-AKT cells treated using PI3K/mTOR inhibitors. A Percent survival of NCI-H146 and NCI-H526 in response to treatment using the indicated compounds for 72 h. *p < 0.05; **p < 0.01; ***p < 0.001 (t-test). B, C Concentration-response cell survival curves of NCI-H146 and NCI-H526 cells pretreated using siRNAs targeting PTEN for 48 h, followed by treatment using GSK2126458 (B) or BAY 80-6946 (C) for an additional 72 h. ***p < 0.001 (two-way ANOVA). D NCI-H146 and NCI-H526 cells were first transfected with siRNAs targeting PTEN for 48 h. After another 12 h treatment using GSK2126458 (1.0 µM), cells were harvested and subjected to Western blot analysis using the indicated antibodies. Levels of c-RICTOR, c-PARP1, PTEN and p-AKT(S473) were quantified and listed below the profiles. The results indicated that c-RICTOR and c-PARP1 were increased in GSK2126458-treated cells depleted for PTEN