MAPK3 and acute myeloid leukemia: Similar to the immunoblot experiments described for MOLM-13 cells above, U-937 AML cells were treated with either vehicle control (DMSO), SBI-4668 (1, 3, 10, or 30 μM), or with RMC-4550 (1 μM) for 24 h and processed for p-ERK1/2 immunoblot analysis (Fig. 5B).