“Using ATRA sensitive NB4 and ATRA-resistant derivative NB4MR2 cell lines, we demonstrate that PPARγ ligand 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid CDDO ) enhances pro-apoptotic and differentiating effects of ATRA in ATRA-sensitive NB4 cells and partially reverses ATRA resistance in NB4MR2 cells.”