S14161 inhibited the PI3K signaling pathway. (A) Myeloma (H929, OPM2, LP1, and KMS11) and leukemia (OCI-AML2 and THP1) cells were starved overnight and then treated with S14161 (S1; 100μM for 2 hours), LY294002 (LY; 100μM for 30 minutes), or DMSO (DM; 2 hours), followed by 100 ng/mL IGF1 for 10 minutes. After incubation, cells were harvested and total proteins isolated. Expression of AKT, phospho-AKT (p-AKT), and β-actin was measured by immunoblotting. (B) KMS11 cells were treated with increasing concentrations of S1 for 0.5, 1, or 2 hours, followed by IGF1 stimulation. Cells were then harvested and total proteins isolated. Expression of AKT, p-AKT, and β-actin was measured by immunoblotting. (C) JJN3 and K562 cells were treated with S1 (2.5μM) or DMSO control for 24 hours. After incubation, cells were harvested and total proteins isolated. Expression of AKT, p-AKT, and β-actin was measured by immunoblotting. (D) Phosphorylated AKT was important for S14161-induced cell death. KMS11 and U266 cells were treated with increasing concentrations of 5μM S1 for 24 hours, followed by apoptosis analysis with annexin V staining. At the same time, KMS11 and U266 cells were subjected to AKT phosphorylation analysis.