Figure 2. PCI-24781 and tamoxifen concertedly down regulate Akt protein and activity in MCF7 cells.

(A) MCF7 cells were treated with increasing concentrations of PCI-24781 for 72 hours and western blotted. MCF7 cells were treated for 72 hours with vehicle (V), 0.1 µM PCI-24781 (P), 10 µM OH-tamoxifen (T), or the combination (PT) and cells extracts were evaluated by western blot (B) for Pan-Akt and active Akt (P^S473) expression or (E) Akt activity in vitro by immunoprecipitating and then incubating phospho-Akt with a GSK-3 substrate and measuring levels of phosphorylated GSK-3. (C) The indicated cell lines were treated with vehicle (V) or 0.1 µM PCI-24781 and 10 µM OH-tamoxifen (PT) for 72 hours and western blotted for active Akt. (D) In cell extracts, levels of Akt isoforms, active Akt (P ^S473and P^S308) and down stream indicators of Akt activity following 48 and 72 hour treatment with 0.1 µM PCI-24781 and 10 µM OH-tamoxifen (PT) are compared to vehicle treated cells (V).