Figure 4.

4EGI-1-mediated Akt feedback activation results from mTORC1 inhibition and is PI3K and mTORC2 dependent. Both MCF7 and ZR-75–1 cells were pretreated with 2 nM RAD001 (A), 5 μM LY294002 (B) or 0.25 μM PP242 (C) for 30–60 min, and then co-treated with 50 μM 4EGI-1. After 12 h, cell lysates were collected and immunoblotted with indicated antibodies. Both MCF7 (D) and ZR-75–1 (E) cells were transfected with control, Rictor or mTOR siRNA for 48 h and then treated with 50 μM 4EGI-1 for 12 h before harvesting cell lysates. The indicated proteins were detected by western blot analysis.