DAC enhances the anti-leukemic potential of HSPC-NK cells through modulation of their maturation, activation, cytolytic functions, and trafficking to the bone marrow. (A-C) Adult NSG mice were infused with HSPC-NK cells and treated with DAC (1.25 mg/m2) for 5 consecutive days. Persistence of NK cells in vivo was supported by subcutaneous administration of IL-15 (1 µg/injection) every 2 to 3 days. Mice were euthanized 1 or 2 weeks after NK cell infusion for detailed ex vivo analysis. (A) Phenotype of HSPC-NK cells analyzed 1 week after the start of DAC treatment. Analysis was performed on cells isolated from the spleen, including 5 mice per treatment group. The relative expression of various maturation and activation markers, as well as adhesion molecules and homing receptor (right panel) and representative dot plots (left panel), is shown. (B) Gene expression profiling for the cytolytic machinery of NK cells, analyzed by quantitative reverse transcription polymerase chain reaction on cells isolated from livers, including 5 mice per treatment group. Data were normalized to human β-actin. (C) Absolute numbers of HSPC-NK cells were determined in peripheral blood (absolute number per milliliter) and mouse bone marrow either 1 week (experiment #1) or 2 weeks (experiment #2) after the start of treatment. Two femurs per mouse were combined in experiment #1, whereas experiment #2 was performed in IF THP-1–bearing mice and absolute NK cell counts were determined in each femur, with (Tumor BM) or without (NBM) tumor. Data shown in panel A were analyzed with 2-way ANOVA and data from panels B and C with an unpaired, 2-tailed Student t test. BM, bone marrow; IF, intrafemoral; ND, no drug; PB, peripheral blood.
