Mir-99Regulates Normal and Leukemic Stem Cell Function

Acute myeloid leukemia (AML) is composed of functionally heterogeneous cells including leukemic stem cells (LSCs), which exhibit the ability to self-renew and propagate disease. It is thought that failure of common chemotherapy regimens is due to insufficient eradication of LSCs. However, the mechanisms that maintain stem cell function in the hematopoietic system are not well understood. MicroRNAs play an important role in the regulation of normal and malignant hematopoietic stem cells. Our studies showed that miR-99,a miRNA highly expressed in AML patient cell populations enriched for LSC activity, is among the most highly expressed miRNAs in hematopoietic stem cells (HSCs), suggesting that miR-99plays a role in regulating normal HSCs as well as LSCs.