Polo-like Kinase-1, Aurora Kinase A and Wee1 Kinase Are Novel Therapeutic Targets in Chronic Myeloid Leukemia

Abstract BackgroundIn chronic myeloid leukemia (CML), Aurora kinase A and Polo like kinase 1 (Plk1), two serine-threonine kinases involved in the maintenance of a functional G2/M checkpoint, may cooperate with the constitutive tyrosine-kinase (TK) activity of the BCR-ABL1 fusion protein increasing DNA damage, promoting the occurrence of additional genomic alterations ultimately driving resistance to TK inhibitors (TKIs) and progression from chronic phase to blast crisis (BC). MethodsIn this study, we propose a new therapeutic strategy based on the combination of Aurora kinase A or Plk1 inhibition with danusertib or volasertib, respectively, and WEE1 inhibition with AZD1775. Apoptotic cell death was quantified by annexin V/propidium iodide staining and flow cytometry. Cell cycle distribution was assessed by PI staining and flow cytometry. Protein expression and activation was assessed by Western Blotting (WB) and Immunofluorescence. Clonogenic assays were performed to evaluate cells sensitivity to the different drugs.ResultsDanusertib and volasertib used as single drugs induced apoptosis and G2/M-phase arrest, associated with accumulation of phospho-WEE1. Subsequent addition of the WEE1 inhibitor AZD1775 in combination significantly enhanced the induction of apoptotic cell death in TKI-sensitive and -resistant cell lines as compared to both danusertib and volasertib alone and to the simultaneous combination. This schedule indeed induced a significant increase of the DNA double-strand break marker γH2AX, forcing the cells through successive replication cycles ultimately resulting in apoptosis. Finally, combination of danusertib or volasertib+AZD1775 significantly reduced the clonogenic potential of CD34+ CML progenitors. ConclusionsOur results may have implications for the development of innovative therapeutic approaches based on Aurora kinase A or Plk1 inhibition associated with WEE1 blocking, aimed to improve the outcomes of patients with multi-TKI-resistant or BC CML.