Abstract
CCAAT/enhancer binding proteins (C/EBPs) play critical roles in myelopoiesis. Dysregulation of these proteins likely contributes to the pathogenesis of myeloid disorders characterized by a block in granulopoiesis. In one such disease, acute promyelocytic leukemia (APL), a promyelocytic leukemia–retinoic acid receptor α (PML-RARα) fusion protein is expressed as a result of a t(15;17) chromosomal translocation. Treatment of PML-RARα leukemic cells with all-trans retinoic acid (ATRA) causes them to differentiate into mature neutrophils, an effect thought to be mediated by C/EBPs. In this study, we assess the potential for cooperativity between increased C/EBP activity and ATRA therapy. We demonstrate that although both C/EBPα and C/EBPϵ can significantly prolong survival in a mouse model of APL, they are not functionally equivalent in this capacity. We also show that forced expression of C/EBPα or C/EBPϵ in combination with ATRA treatment has a synergistic effect on survival of leukemic mice compared with either therapy alone.
All‐
trans
retinoic acid increases matrix metalloproteinase‐9 expression in murine myeloid dendritic cells through retinoic acid receptor‐α interaction with and histone acetylation of the promoter