Figure 5. Effects of vildagliptin alone or in combination with imatinib or nilotinib on engraftment of CD34⁺ CML cells in NSG mice.

(A,B) Purified CD34⁺ cells obtained from the BM of three CML patients (patients #1, #2, and #3) were injected intravenously into irradiated NSG mice (n = 4–5 mice per group). Mice were treated with solvent control, vildagliptin alone, imatinib alone, or a combination of imatinib and vildagliptin (left panels) or solvent control, vildagliptin alone, nilotinib alone, or a combination of vildagliptin and nilotinib (right panels). After 26 weeks, mice were sacrificed and BM cells were analyzed for the presence of engrafted viable (TO-PRO3-negative) CD45⁺/CD33⁺ CML cells by flow cytometry. In (A), results are expressed as a percentage of CD45⁺/CD33⁺ human cells (of all viable BM cells) and represent the mean ± SD of all mice per group. In (B), results from all mice in all corresponding groups relative to control (all three independent experiments) are shown. (C) Formalin-fixed and paraffin-embedded BM sections obtained from NSG mice (pelvic samples from NSG experiment with patient #2) receiving vildagliptin, imatinib, or vildagliptin + imatinib (left panel) or vildagliptin, nilotinib, or vildagliptin + nilotinib (right panel) were stained with a human CD45 antibody. Human CD45⁺ cells were counted under an inverted microscope (Olympus, Tokyo, Japan). Results show the percentage of human engrafted CD45⁺ cells (of all BM cells) counted by microscopy and represent the mean ± SD from all mice per group.