Combination of RA and arsenic restores PML and SUMO-1 nuclear body formation. (A-B) Primary leukemic blasts from one NPM1 mutated AML patient on days 0 and 8 after in vivo treatment with RA/arsenic were analyzed by confocal miscroscopy. NPM1 was stained with anti-NPM1 (WT + c) antibody (green); PML was stained with anti-PML antibody (red). (C-D) OCI-AML3 cells (left panels) and THP-1 cells (right panels) treated with RA/arsenic for up to 48 hours and analyzed by confocal miscroscopy. (C) Treatment of OCI-AML3 cells with RA/arsenic leads to PML nuclear body reorganization. (D) Treatment of OCI-AML3 cells with RA/arsenic leads to SUMO-1 nuclear body formation. The results (C-D) depict one representative of 3 independent experiments. Graphs show quantification of PML and SUMO-1 NBs, as averages of one Z-section/cell from 30 different cells. Significant P values are indicated by asterisks.