PCI-24781 and <b>tamoxifen concertedly down regulate Akt protein</b> and <b>activity in MCF7 cells.</b>

<p>(<b>A</b>) 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>B</b>) for Pan-Akt and active Akt (P^S473) expression or (<b>E</b>) Akt activity <i>in vitro</i> by immunoprecipitating and then incubating phospho-Akt with a GSK-3 substrate and measuring levels of phosphorylated GSK-3. (<b>C</b>) 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. (<b>D</b>) 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).