NUP98-fusion–protein-driven AML is highly dependent on sustained oncoprotein expression in vivo. (A) Schematic illustration of the experimental workflow to induce downregulation of oncogene expression in vivo. GFP/CD45.2-positive leukemia cells (1 × 106) were transplanted into sublethally irradiated secondary recipients. Animals were treated with Dox (4 mg/mL) after an engraftment period of 15 days. (B) Representative bioluminescence imaging of untreated vs Dox-treated mice transplanted with NUP98/NSD1-expressing leukemia cells. (C) Kaplan-Meier survival curves with statistical analyses using Log-rank tests of mice transplanted with leukemia cells expressing indicated NUP98-fusion proteins receiving either no treatment or Dox (4 mg/mL) (n ≥ 4). (D-E) Flow cytometric analyses of bone marrow–derived leukemia at indicated time points after Dox treatment of mice (mean ± SD; n = 3). (D) Quantification of mean fluorescence intensity (MFI) of GFP. (E) Quantification of the myeloid differentiation markers Mac-1/Gr-1 and the progenitor cell marker c-Kit. (F) Representative cytospin images of untreated vs Dox-treated (8 days) NUP98/JARID1A-expressing cells in vitro, ×400 original magnification. *P < .05, **P < .01, ***P < .001, ****P < .0001.