DataSheet_1_Polo-like kinase-1, Aurora kinase A and WEE1 kinase are promising druggable targets in CML cells displaying BCR::ABL1-independent resistance to tyrosine kinase inhibitors.pdf

In chronic myeloid leukemia (CML), Aurora kinase A and Polo like kinase 1 (PLK1), two serine-threonine kinases involved in the maintenance of genomic stability by preserving a functional G2/M checkpoint, have been implicated in BCR::ABL1-independent resistance to the tyrosine kinase inhibitor (TKI) imatinib mesylate and in leukemic stem cell (LSC) persistence. It can be speculated that the observed deregulated activity of Aurora A and Plk1 enhances DNA damage, promoting the occurrence of additional genomic alterations contributing to TKI resistance and ultimately driving progression from chronic phase to blast crisis (BC). In 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. Danusertib 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 from BC patients. Our results may have implications for the development of innovative therapeutic approaches aimed to improve the outcomes of patients with multi-TKI-resistant or BC CML.

在慢性髓系白血病（CML）中，极光激酶A（Aurora kinase A）与Polo样激酶1（PLK1）属于两类丝氨酸/苏氨酸激酶，可通过维持功能性G2/M检验点保障基因组稳定性，二者均与BCR-ABL1非依赖型甲磺酸伊马替尼（酪氨酸激酶抑制剂，TKI）耐药以及白血病干细胞（LSC）存活密切相关。有研究推测，极光激酶A与PLK1的活性失调会加剧DNA损伤，促进额外基因组变异的发生，进而推动TKI耐药的产生，并最终促使疾病从慢性期进展为急变期（BC）。本研究提出了一种全新的治疗策略，即分别联合极光激酶A或PLK1抑制剂达努塞替（danusertib）、伏拉塞替（volasertib），以及WEE1抑制剂AZD1775。单药使用达努塞替或伏拉塞替可诱导细胞凋亡与G2/M期阻滞，并伴随磷酸化WEE1的积累。与单药达努塞替、单药伏拉塞替以及同时联合给药组相比，后续加用WEE1抑制剂AZD1775的联合给药方案，可显著增强TKI敏感及耐药细胞系的凋亡诱导效果。该给药方案确实能显著提升DNA双链断裂标记物γH2AX的水平，迫使细胞进入连续的复制周期，最终引发细胞凋亡。最终，达努塞替或伏拉塞替联合AZD1775的给药方案，可显著降低急变期患者CD34阳性CML祖细胞的集落形成能力。本研究结果可为开发创新性治疗方案提供参考，以改善多TKI耐药或急变期CML患者的预后。