Description
Using BCR-ABL-induced chronic myeloid leukemia (CML) as a disease model for leukemia stem cells (LSCs), we showed that BCR-ABL down-regulates the B lymphoid kinase (Blk) gene in leukemia stem cells in CML mice and that Blk functions as a tumor suppressor in LSCs and suppresses LSC function. Inhibition of this Blk pathway accelerates CML development, whereas increased activity of the Blk pathway delays CML development. To identify the pathways in which Blk regulates function of LSCs, we performed a comparative DNA microarray analysis using total RNA isolated from non-BCR-ABL-expressing Lin-Sca-1+c-Kit+, BCR-ABL- and BCR-ABL-Blk expressing LSCs. This analysis revealed a large group of candidate genes that exhibited changes in the levels of transcription in the Blk expressing LSCs, and uncovered the molecular mechanisms by which Blk suppresses LSCs and CML development.