To directly test if APL cells are sensitized to apoptosis by LSD1i, we assessed the effect of TRAIL on NB4 cells upon attenuated insulin/IGF1 signaling, using OSI-906, and/or pharmacological or genetic ablation of LSD1 (using LSD1i or LSD1-KO NB4 cells, respectively). Here, IGF1 is linked to acute promyelocytic leukemia.