Ba f3 cells

U937, HL-60, and 293T cells were purchased from ATCC. Ba/F3 cells were purchased from DSMZ. THP-1, MV4-11, and MOLM-14 cells were provided by Scott Armstrong. MOLM-13 cells were provided by Benjamin Ebert. All cell lines were maintained in RPMI 1640 (Cellgro) supplemented with 1% penicillin/streptomycin (PS; Cellgro) and 10% FBS (Sigma-Aldrich) at 37°C with 5% CO₂. The 293T cells were maintained in Dulbecco’s modified Eagle’s medium (Invitrogen) supplemented with 10% FBS (Invitrogen) and 1% PS. Ba/F3 cells were maintained in RPMI-1640 supplemented with 1% PS, 10% FBS, and IL-3 (PeproTech).
Primary patient AML blasts were collected from peripheral blood or bone marrow aspirate after obtaining informed consent under Dana-Farber Institute Internal Review Board–approved protocols. Mononuclear cells were isolated using Ficoll-Paque Plus (GE Healthcare), and red blood cells were lysed (eBioscience). AML blasts from patients were maintained in SFEM (Stemcell Technologies) with SCF, FLT3L, IL-3, IL-6, and GCSF (PeproTech). For drug treatment of primary AML cells, RPMI-1640 with PS and FBS were used.
Murine MLL-AF9–expressing leukemia cells were obtained from a quaternary bone marrow transplant model from Benjamin Ebert’s laboratory. Cells were maintained in SFEM media (Stemcell Technologies) with murine IL-3, IL-6, and SCF cytokines (PeproTech).

K562 and Ba/F3 cells (RIKEN Cell Bank, Tsukuba, Japan), and KCL22 cells (JCRB Cell Bank, Osaka, Japan), were cultured in RPMI‐1640 medium (Nacalai Tesque, Kyoto, Japan) supplemented with 10% or 20% (KCL22 cells) FBS (Life Technologies, Grand Island, NY, USA) plus antibiotics (Nacalai Tesque). Prior to introduction of the BCR/ABL gene, Ba/F3 cells were cultured with 10 ng/mL interleukin‐3 (Peprotech, Rocky Hill, NJ, USA). K562 cells that survived in medium containing 1 μmol/L IM (named K562‐IM1e [“e” denotes “exposure” to 1 μmol/L IM]) were generated as described previously,21 with minor modifications. Briefly, K562 cells were initially cultured in the presence of 0.1 μmol/L IM. Then, the concentration of IM in the medium was subsequently increased by 0.1‐0.2 μmol/L every 6‐8 weeks. K562‐IM1e cells were maintained in medium containing 1 μmol/L IM.