SGK3 knockdown in the broader context of MEK1,2/PI3K blockade.

<p>MM cells were electroporated with stealth siRNAs against EGFP or SGK3 and drugs were added at day 2 post-electroporation for a further 3-day incubation. Cell death was measured by annexin V/PI staining and FACS analysis. Error bars denote s.e.m. based on 3 independent experiments. The survival rates were calculated relative to DMSO-treated cells. The absolute survival rates for the experimental pairs in these experiments (DMSO treated stEGFP vs. DMSO treated stSGK3 transfected cells) were 92.7% vs. 93.6% (AMO-1) and 92.7% vs. 91.9% (L-363), i.e. there was no substantial difference between control cells and SGK3 knockdown cells. Titration of BYL-719 and choice of its concentration are detailed in [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0122689#pone.0122689.ref015" target="_blank">15</a>]. Of note, the strong synergistic effect observed in AMO-1 cells for the combination of PI3K-p110α inhibitor BYL-719 and MEK1,2 inhibitor PD0325901 is not observed when the PI3K-p110α inhibitor is substituted with an Akt inhibitor (MK-2206 or Akti1,2), but it is also not mirrored by the combination of MEK1,2 inhibition and SGK3 depletion.