Abstract：
Hyperactive FMS-like receptor tyrosine kinase-3 mutants with internal tandem duplications (FLT3-ITD) are frequent driver mutations of aggressive acute myeloid leukemia (AML). Inhibitors of FLT3 produce promising results in rationally designed cotreatment schemes. Since FLT3-ITD modulates DNA replication and DNA repair, valid anti-leukemia strategies could rely on a combined inhibition of FLT3-ITD and regulators of cell cycle progression and DNA integrity. These include the WEE1 kinase which controls cell cycle progression, nucleotide synthesis, and DNA replication origin firing. We investigated how pharmacological inhibition of FLT3 and WEE1 affected the survival and genomic integrity of AML cell lines and primary AML cells. We reveal that promising clinical grade and preclinical inhibitors of FLT3 and WEE1 synergistically trigger apoptosis in leukemic cells that express FLT3-ITD. An accumulation of single and double strand DNA damage precedes this process. Mass spectrometry-based proteomic analyses show that FLT3-ITD and WEE1 sustain the expression of the ribonucleotide reductase subunit RRM2, which provides dNTPs for DNA replication. Unlike their strong pro-apoptotic effects on leukemia cells with FLT3-ITD, inhibitors of FLT3 and WEE1 do not damage healthy human blood cells and murine hematopoietic stem cells. Thus, pharmacological inhibition of FLT3-ITD and WEE1 might become an improved, rationally designed therapeutic option.
摘要：
具有内部串联重复的过度活跃的FMS样受体酪氨酸激酶3突变体（FLT3-ITD）是侵袭性急性髓细胞性白血病（AML）的频繁驱动突变。FLT3的抑制剂在合理设计的共处理方案中产生了有希望的结果。由于FLT3-ITD调节DNA复制和DNA修复，有效的抗白血病策略可能依赖于FLT3-ITD的联合抑制以及细胞周期进程和DNA完整性的调节因子.这些包括控制细胞周期进程的WEE1激酶，核苷酸合成，和DNA复制起点激发。我们研究了FLT3和WEE1的药理学抑制如何影响AML细胞系和原代AML细胞的存活和基因组完整性。我们发现，FLT3和WEE1的有希望的临床分级和临床前抑制剂可协同触发表达FLT3-ITD的白血病细胞的凋亡。单链和双链DNA损伤的积累先于此过程。基于质谱的蛋白质组分析显示FLT3-ITD和WEE1维持核糖核苷酸还原酶亚基RRM2的表达,其为DNA复制提供dNTP。与FLT3-ITD对白血病细胞的强烈促凋亡作用不同，FLT3和WEE1的抑制剂不会损害健康的人血细胞和鼠造血干细胞。因此，FLT3-ITD和WEE1的药理学抑制可能会得到改善，合理设计的治疗选择。
