Role of HFI-1α in the development and sensitivity of T-ALL in vivo. (A) Protocol of the experimental settings. T-ALL#1 was transduced with shCTL (Cherry⁺) or shHIF-1α (GFP⁺) vectors. Sorted shHIF-1α (GFP⁺) cells were mixed at a 1:1 ratio with sorted shCTL (Cherry⁺) cells. A total of 10 000 mixed leukemic cells were transplanted into NSG recipients. (B) Plots of the flow cytometry analysis of the GFP⁺/Cherry⁺ cell mixture before mice injection. (C) The NSG mouse recipients were monitored for T-ALL development by BM cell samplings 9 weeks after transplantation. Shown are representative plots from mouse #3. GFP⁺/Cherry⁺ percentage are given relative to gated human CD45⁺ T-ALL cells before and after chemotherapeutic treatments. (D) Efficacy of chemotherapy in 6 mice measured before and after 1 week of drug treatment. The percentage of human CD45⁺ leukemic cells in the BM is shown for each mouse. (E) Percentage of shHIF-1α/GFP⁺ cells and (F) of shCTL/Cherry⁺ cells in human CD45⁺ leukemic cells before and after treatment of mice. (G) HIF1α expression in T-ALL#1 after transplantation in immune-deficient mice. Shown are results from the BM of 2 mice. BM cells were recovered after 1 week of chemotherapy treatment. Statistics were determined using the Wilcoxon test: *P < .05.