Fig. 3: Increased incidence of leukemic transformation in Ppm1d^T/+ mice upon irradiation.

A Schematic representation of the experimental setup (left panel). WT and Ppm1d^T/+ mice were injected intraperitoneally (i.p.) with 150 mg/kg 5-FU as indicated (black arrows). The x-axis indicates days. Kaplan–Meier survival analysis of four WT and four Ppm1d^T/+ mice intravenously injected with 5-FU as indicated in the left panel. Mantle–Cox test was used to assess the statistical significance of obtained results (p = 0.0262). B Schematic representation of the experimental setup. 12-weeks-old WT and Ppm1d^T/+ mice were irradiated with 3 Gy sub-lethal dose and subjected to 4 irradiation cycles. The interval between irradiation is indicated as weeks (w) or months (m). Each group contained at least 8 animals from 2 independent experiments. C Leukemia-free survival of mice exposed to sub-lethal irradiation as defined in panel B. Proportion of animals with leukemia in WT and Ppm1d^T/+ mice from Kaplan–Meier survival plot is indicated on the right. D Representative flow cytometry plots from indicated mouse genotypes: Healthy non-irradiated mouse (WT; green), healthy irradiated mouse (WT#2; black), and leukemic Ppm1d^T/+ mouse (Ppm1d^T/+#2; red). Numbers indicate the percentage of cKit⁺ cells (upper box) and Gr1⁺CD11b⁺ granulocytes (lower box) in total BM. E Re-transplantation scheme of WT and Ppm1d^T/+ primary leukemias from panel C. 1 × 10⁵ primary leukemic WT and Ppm1d^T/+ (Ly 5.2) BM cells were transplanted into sub-lethally irradiated recipient mice (Ly5.1). Leukemia-free survival of re-transplanted leukemic mice is shown. At least 8 mice were used per group. F Body weight (left) and spleen weight (right) of non-treated healthy WT mice (green), and mice re-transplanted with BM cells from irradiated donors. The weight of the body and spleen is presented as mean ± s.d. Statistical significance was determined by using 2-tailed Student’s t-tests (***p < 0.001, **p < 0.01, *p < 0.05). At least three mice were used per group. G Representative pictures from spleens isolated from a healthy WT mouse (WT), a WT irradiated leukemic mouse (WT#1), and a Ppm1d^T/+ irradiated leukemic mouse (Ppm1d^T/+#2). H Representative flow cytometry plots from indicated mouse genotypes: healthy WT control (WT), irradiated WT non-leukemic (WT#2), irradiated WT leukemic (WT#1), irradiated Ppm1d^T/+ leukemic (Ppm1d^T/+#2), and irradiated Ppm1d^T/+ leukemic (Ppm1d^T/+#4). Plots show Gr1 CD11b expression in BM. The upper right quadrant shows granulocytes (Gr1⁺CD11b⁺). I BM cytospins stained with May-Grünwald Giemsa. Representative images are shown: healthy WT control (WT), irradiated WT non-leukemic (WT#2), irradiated WT leukemic (WT#1), irradiated Ppm1d^T/+ leukemic (Ppm1d^T/+#2), and irradiated Ppm1d^T/+ leukemic (Ppm1d^T/+#4). The scale bar represents 10 µm.