Inhibition of mTOR augments AKT signaling in CLL, which can be overcome by a dual PI3K/mTOR inhibitor. (A) CLL cells were pretreated with everolimus (1 μM) or PF-04691502 (1 μM) for 2.5 hours prior to treatment with soluble anti-IgM (IgM) for 15 minutes. Immunoblotting was performed for phosphorylated AKT (pAKT^S473), S6 kinase (pS6K^T389), and S6 (pS6 ribsosomal subunit^S235/236). Bcl-2 was used as a loading control. The fold change in (B) pAKT^S473 (n = 7), (C) pS6K^T389 (n = 6), (D) pS6^S235/236 (n = 7), and (E) AKT^T308 (n = 5) compared to the untreated basal control after the various treatments described in panel A. *P < .05, **P < .01. Error bars represent SEM. NA, untreated basal control; SEM, standard error of the mean.