Concomitant inhibition of mTORC1 and p110δ PI3K activity with RAD001 and IC87114, respectively, induces additive inhibition of blast cell proliferation. (A) Blast cells (10⁵/mL) from the 19 patients were incubated 48 hours in duplicate in 5% FCS MEM under the following conditions: control (C), 10 nmol/L RAD001 (R), 10 μmol/L IC87114 (IC), 10 nmol/L RAD001 and 10 μmol/L IC87114 (R + IC), and pulsed for 6 hours with [³H]thymidine (1 μCi, [37 kBq]). A Student t test was performed to compare proliferation rates between the different conditions. Significance was: C/R, P <.001; C/IC, P <.001; R/R + IC, P <.001; IC/R + IC, P <.001. The WB analysis shows the effect of inhibitors on Akt (Ser 473) and P70S6K (Thr 389) phosphorylation. (B) BM blast cells (10⁵/mL) from 4 AML samples were incubated 48 hours in triplicate in 5% FCS MEM, with or without inhibitors as described below. They were then pulsed 6 hours with [³H]thymidine 1 μCi [37 kBq]. The amount of radioactivity incorporated was determined by trichloracetic acid precipitation. In the top panel, increasing amounts (from 1.25 to 20 nmol/L) of RAD001 were used, without (top line) or with a constant concentration of IC87114 (10 μmol/L). In the bottom panel, increasing (from 1.25 to 20 μmol/L) amounts of IC87114 were used, without (top line) or with a constant concentration of RAD001 (10 nmol/L). Error bars indicate standard deviations.