DYRK1a-NIK axis mediates B-ALL induction in a mouse model. (A) Flow cytometric analysis of BAFFR expression using either normal bone marrow control cells or B-ALL cells (GFP⁺) isolated from B-ALL mice generated by transplanting lethally irradiated C57BL/6 recipients with BCR-ABL-GFP–transduced WT bone marrow cells. (B,I) Immunoblot analysis of the indicated proteins in whole-cell lysates of normal bone marrow control (BM Ctrl) or GFP⁺ B-ALL cells freshly sorted from B-ALL mice generated using WT or Dyrk1a^BKO bone marrow cells (day 40 after bone marrow transplantation). (C) Flow cytometric analysis of apoptotic cells based on annexin V and propidium iodide staining in freshly isolated WT and Dyrk1a^BKO B-ALL cells (GFP⁺). (D) Flow cytometric analysis of proliferating cells (Ki67⁺) in freshly isolated WT and Dyrk1a^BKO B-ALL cells (GFP+). (E) Survival curve of primary B-ALL mice generated with BCR-ABL-GFP–transduced bone marrow cells from wild-type, Dyrk1a^BKO, or Map3k14^BtgDyrk1a^BKO mice. (F,G) Survival curve (I) and frequency of leukemic cells (GFP⁺) in the peripheral blood lymphocytes (J) of secondary B-ALL mice generated by transplanting sublethally irradiated C57BL/6 recipients with B-ALL cells sorted from the indicated primary B-ALL mice. (H) qRT-PCR analysis of Bcl-2 and Bcl-XL expression using either normal bone marrow control cells or B-ALL cells (GFP+) freshly isolated from B-ALL mice. (J) Immunoblot analysis of Bcl-2 and Bcl-XL in BALL1 or BALL1-NIK cells cultured for 8 days in the presence (+) or absence (–) of BAFF and EHT1610. Data are representative of 2 independent experiments. Summary graphs are mean ± SD values based on multiple mice (C-G) or triplicated samples (H), and P values are determined by an unpaired, 2-tailed Student t test (C-D,H), log-rank Mantel-Cox test (E,F), or two-way ANOVA with Bonferroni correction (G). *P < .05; **P < .01; ***P < .001.