Loss of KLF4 impairs self-renewal and survival in CML leukemia stem/progenitor cells through derepression of the DYRK2 gene.
Stabilization of DYRK2 protein inhibits survival and self-renewal in leukemia stem/progenitor cells via c-Myc depletion and p53 activation.
Leukemia stem cells are a rare population with a primitive progenitor phenotype that can initiate, sustain, and recapitulate leukemia through a poorly understood mechanism of self-renewal. Here, we report that KLF4 promotes disease progression in a murine model of chronic myeloid leukemia (CML)-like myeloproliferative neoplasia by repressing an inhibitory mechanism of preservation in leukemia stem/progenitor cells with leukemia-initiating capacity. Deletion of the Klf4 gene severely abrogated the maintenance of BCR-ABL1(p210)-induced CML by impairing survival and self-renewal in BCR-ABL1+ CD150+ LSK leukemic cells. Mechanistically, KLF4 repressed the Dyrk2 gene in leukemic stem/progenitor cells; thus, loss of KLF4 resulted in elevated levels of DYRK2 kinase, which were associated with inhibition of survival and self-renewal via depletion of c-Myc protein and p53 activation. In addition to transcriptional regulation, stabilization of DYRK2 protein by inhibiting ubiquitin E3 ligase SIAH2 with vitamin K3 promoted apoptosis and abrogated self-renewal in murine and human CML stem/progenitor cells. Altogether, our results suggest that DYRK2 is a molecular checkpoint controlling both p53 and c-Myc-mediated regulation of survival and self-renewal in CML cells with leukemic-initiating capacity that can be targeted with small molecules.