Hematopoietic Cell Lines And Patient Samples Show A Correlation Between Upregulated Msi2 And Bcr-Abl Expression

Increased expression of Musashi 2 (also known as MSI2), a mRNA binding protein, is reported to trigger progression of chronic myeloid leukemia (CML) from chronic phase (CP) to blast crisis (BC), which is frequently fatal. The data imply that MSI2 is upregulated by HOXA9 leading to disruption of the critical hematopoietic stem cell (HSC) fate decisions via the NUMB-NOTCH signaling pathway. These events lead to HSC proliferation, impaired myeloid differentiation and are associated with worse prognosis in CML and acute myeloid leukemia (Kharas, et al. Nat Med 2010; 16:903; Ito, et al. Nature 2010; 466:765). Previously, we confirmed increased MSI2 levels in CML patients in blast crisis (BC) compared with those in CP, irrespective of lymphoid or myeloid transformation (Kaeda, et al. Blood. 2011;118;supplement). To further elucidate this regulatory pathway we assessed whether HOXA9 expression correlated with increased MSI2mRNA levels and upregulation of NOTCH.