miR-146a Expression Level as a Novel Putative Prognostic Marker for Acute Promyelocytic Leukemia

BACKGROUND Although the curative rate for acute promyelocytic leukemia (APL) has been improved over decades, long-term prognosis is still poor. The genetic pathways that regulated cell lineage fate during the development of APL remain unclear. METHODS We investigated the correlations of miR-146a expression with its target gene Smad4 and the biological behaviors of NB4 cells. We also analyzed their expression in clinical samples from APL patients. RESULTS miR-146a influenced apoptosis and proliferation in NB4 cells. miR-146a influenced endogenous Smad4 protein levels in APL cells. miR-146a expression levels were positively correlated with white cell counts and PML/RARα fusion protein expression. miR-146a expression levels were negatively correlated with Smad4 protein and the helper T cell (Th)/the suppressor T cell (Ts) ratio in these patients. CONCLUSIONS These findings indicated that miR-146a played an important role in the development of APL in part through the repression on Smad4 protein expression. miR-146a functioned as an oncogene and may be a novel prognostic biomarker in APL.