Cell lines and viability assays

Eμ-Myc mouse lymphoma and HoxA9-Meis1-transformed mouse acute myeloid leukaemia cell lines were generated and cultured as previously described (16,17). Eμ-Myc lymphoma cell lines (#AH15A, AF47A) were cultured in high-glucose Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum (FBS), 50 μM β-mercapto-ethanol and 100 mM asparagine. HoxA9-Meis1 myeloid cells were grown in DMEM with 10% FBS and murine IL-3 (10 ng/ml). Both cell lines were maintained at 37°C in 10% CO₂ and regularly verified as mycoplasma negative. For drug sensitivity assays, Eμ-Myc lymphoma cells or Hoxa9-Meis1 myeloid cells, or their derivatives, were seeded into white 96-well plates (Greiner, 655083) at a density of 5 × 10⁴ cells/well and treated with drugs (typically 0–10 μM, 5-point serial dilution 1:4), including EIDD-1931 (S0833, SelleckChem), azacitidine (S1782, SelleckChem) and decitabine (S1200, SelleckChem). Cell viability was assessed at 48 h using CellTiter-Glo 2.0 Cell Viability Assay (Promega, G9241).