Extended Data Figure 3 |. Resistance to BET inhibitors emerges from leukaemia stem cells.

a, Transplant cohorts and survival of mice injected with vehicle-treated and resistant clones in limit dilution analyses of primary syngeneic transplants displayed in Fig. 2d, e. b, Experimental strategy for derivation of in vivo resistance to BET inhibitors in a MLL–AF9 leukaemia model. After primary transplant of a vehicle-treated clone, serial transplant of either I-BET-exposed or I-BET-naive leukaemias, derived from whole bone marrowof diseased mice, was undertaken until loss of I-BET-mediated survival advantage was observed. Treatment was started on days 11–13. c, Progressive loss of I-BET-mediated survival advantage observed in serial transplant generations. Kaplan–Meier curves of serial transplant generations. Second transplant: I-BET naive n = 6, I-BET exposed n = 6. Third transplant: I-BET naive n = 2, I-BET exposed n = 3. Fourth transplant: I-BET naive n = 2, I-BET exposed n = 3. Fifth transplant: I-BET naive n = 4, I-BET exposed n = 5. d, Limit dilution analyses of leukaemias derived from bone marrow of diseased mice chronically exposed to I-BET after the fourth transplant demonstrates that less than 10 cells are reliably able to transfer leukaemia. Kaplan–Meier curves of C57BL/6 mice injected with indicated number of cells. e, Chronic I-BET exposure significantly enriches for leukaemia stem cells in vivo. f, Transplant cohorts and survival of limit dilution analyses of data displayed in d and e. g, Gating strategy for identification of L-GMPs in whole mouse bone marrow.