Targeting FLT3-TAZ Signaling to Suppress Drug Resistance in Blast Crisis Chronic Myeloid Leukemia

Although the development of tyrosine kinase inhibitors (TKIs), including BCR-ABL1 targeted therapies, rendered chronic myeloid leukemia (CML) a manageable condition, acquisition of drug resistance during blast crisis (BC) progression remains a critical challenge. Here, we elucidate the significance of FLT3 signaling in the acquisition of drug resistance in BC-CML. Mechanistically, FLT3 expression in CML cells activated FLT3-JAK-STAT3-TAZ-TEAD-CD36 pathway, which conferred resistance to wide range of tyrosine kinase inhibitors (TKIs). Remarkably, a subgroup of BC-CML patients who expressed FLT3 showed strong correlation with the prognostic factors of CML independent of recurrent BCR-ABL1 mutations. We demonstrate that combining FLT3 inhibitors with BCR-ABL1 targeted therapies or single treatment with ponatinib can overcome drug resistance and promote cell death in patient-derived FLT3+ BC-CML cells and mouse xenograft models. Our findings reveal the mechanism of FLT3-mediated drug resistance in BC progression and suggest the inclusion of FLT3 as a therapeutic target for this defined group of patients. RNA-seq of K562 cells with indicated conditions