Pim2 and Akt are parallel upstream mTOR-C1 regulators in MM. (A) Combinational inhibition of both Pim and PI3K/Akt leads to more pronounced reduction of mTOR-C1 activity than inhibiting Pim or PI3K/Akt alone in MM cell lines. MM cell lines KMS-11, KMS-26, KMS-34, and H929 were treated with either LGB321 (1.0 μM) or BKM120 (1.0 μM), or both LGB321 and BKM120 for 2 hours. Cell lysates were examined for p-P70 (T389), p-AKT (S473), p-PRAS40 (T246), and p-BAD (S112). p-TSC2 levels were examined by p-Akt substrate Ab following TSC2 IP. (B) Model: Pim2 primarily regulates mTOR-C1 activity through phosphorylating TSC2, while Akt mainly exerts its modulation on mTOR-C1 pathway through regulating p-PRAS40.