MLN4924 inhibits PI3K/mTOR signaling pathway. (A) MM.1R and U266 cells were treated as with Figure 1C and analysis of total and phosphoprotein expression was evaluated using western blot. (B) Primary human MM cells were treated with 2.5 or 5 µM MLN4924 for 24 hours; apoptosis and specific signal pathway were checked using western blot analysis. (C) The MM.1R cell was treated with 2.5 µM MLN4924 or control for the indicated time points. Total and phosphoprotein expression were again tested using western blot analysis.