Extended Data Figure 2 |. Resistance to BET inhibitors also arises from an immature cell compartment in MLL–ENL leukaemia.

a, Strategy for the generation of resistant cell lines from primary HSPC after retroviral transduction with the oncogene MLL–ENL. The parental cell line was serially re-plated in cytokine supplemented semi-solid media containing either vehicle (0.1% DMSO) or 400 nMI-BET (~IC₄₀ of parental cell line). Cells in each plate were then washed and transferred to liquid culture to generate cell lines. Resistant cell lines were subsequently exposed to increasing selection pressure in liquid culture. Vehicle-treated cell lines and the parental cell line were identically passaged. b, Resistant cell lines bearing MLL–ENL are smaller and demonstrate homogeneity in size and complexity (FSC^mid/SSC^low) in addition to exhibiting an immature immunophenotype (Gr1⁻/CD11b⁻). Representative FACS analysis of vehicle-treated and resistant cell lines. c, Resistant cell lines bearing MLL–ENL demonstrate increased expression of WNT/β-catenin pathway genes. qRT–PCR data performed in biological triplicate (mean ± s.d.).