Fig. 3: IL7R is required for BCP-ALL leukemogenesis.

a BM-derived pre-B cells from WT mice were transduced with either an empty vector (EV) or with BCR-ABL1. Viability of the cells after IL7 withdrawal was determined by flow cytometry (left). The enrichment of CD19⁺GFP⁺ (right). The results are representative of three independent experiments. b Quantification of viable CD19⁺GFP⁺ cells relative to control after IL7 withdrawal (n = 7 per group, and error bars represent mean ± SEM. Unpaired t-test, two-sided, exact p value ****p < 0.000000000000001). AU arbitrary unit. c–g Il7rα^fl/fl pre-B cells were transformed with BCR-ABL1 and were then transduced with either ER^T2 or Cre-ER^T2. Cells were treated with either tamoxifen (Tam) to induce Cre expression, or with ethanol (Et). c PCR analysis for Il7rα deletion (Il7rα^∆), Srp20 was used as a loading control. Cells transduced with ER^T2 were used as control. The results are representative of three independent experiments. bp base pair. d Extracellular staining for IL7R protein in Il7rα^fl/fl pre-B cells after 72 h of Cre-induction. The results are representative of three independent experiments. e The percentage of living cells were determined by flow cytometry using Sytox as an excluding dead cell stain. N = 3 independent samples per group, and error bars represent mean ± SD. One-way ANAOVA. Dunnett’s multiple comparisons test was performed to day 5, compared with control group (ER^T2 Et). Adjusted p values: ER^T2 Et vs. ER^T2 Tam n.s. p = 0.1769, ER^T2 Et vs. Cre-ER^T2 Et n.s. p = 0.6325, ER^T2 Et vs. Cre-ER^T2 Tam ****p < 0.0001. f Luciferase bioimaging and g survival curves of NOD-SCID mice that were injected with 1 × 10⁶ Il7rα^fl/fl-BCR-ABL1 pre-B cells containing either a Cre-ER^T2 construct or an ER^T2. (n = 21 per group). Mantel–Cox-log-rank test, ***p value = 0.0002.