TAT-NPMΔC suppresses proliferation and induces apoptosis in Fancc−/− preleukemic stem cells. (A) Clonogenic assay. WT BM cells or Fancc−/− preleukemic cells cultured in semi-solid medium containing 30 μg/mL of the indicated proteins were analyzed for colony-forming efficiency of hematopoietic progenitors. Data represents the mean plus or minus SD of 3 experiments. (B) Bone marrow transplantation assay. 10⁶ WT BM cells or Fancc−/− preleukemic cells (CD45.2+) were transplanted, along with 10⁶ competitor cells from B6.BoyJ mice (CD45.1+), into lethally irradiated recipient (B6.BoyJ) mice, which after 10 days were injected intraperitonally with the indicated proteins (10 mg/kg in 0.5 mL PBS and 10% glycerol) twice a week for 4 weeks. Engraftment was evaluated at 4 weeks after transplantation. Data represent mean plus or minus SD of 3 independent experiments, each with 6 animals (total, 18 mice). (C) TAT-NPMΔC induces growth arrest and apoptosis in colony-forming and repopulating Fancc−/− cells. Bone marrow cells from colonies described in panel A or bone marrow cells from recipient mice described in panel B were stained with propidium iodide (PI) followed by analysis for cell-cycle distribution. Shown are representative flow cytometric presentations of 3 colony assays or 3 to 4 recipients in each treatment.