Aberrant microRNA-182 expression is associated with glucocorticoid resistance in lymphoblastic malignancies

Glucocorticoid (GC) resistance in lymphoblastic malignancies is related to treatment failure and is a marker of poor prognosis. Previous studies have suggested that microRNA-182 (miR-182) functions as an oncogene and plays a role in tumorigenesis, through regulation of FOXO3A. FOXO3A has been implicated in tumor suppression and GC-induced apoptosis, suggesting that FOXO3A has potential as a therapeutic target. Herein we investigated the role of miR-182 in GC sensitivity in lymphoblastic malignancies. Expression of miR-182 was consistently higher in human and mouse GC-resistant cell lines than in GC-sensitive cell lines. Furthermore, increased expression of miR-182 reduced total FOXO3A expression but had no significant effect on phospho-FOXO3A. Additionally Bim, as a downstream target of FOXO3A, was reduced by overexpression of miR-182, and increased by down-regulation of miR-182. These results demonstrate that miR-182 is involved in glucocorticoid resistance, via targeting of FOXO3A, and that restoration of miR-182 is a potentially promising therapeutic strategy in lymphoblastic malignancies.