Garcia Tamara B, Fosmire Susan P, Porter Christopher C
Medical Scientist Training Program, University of Colorado School of Medicine, Aurora, CO, United States.
Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO, United States.
Leuk Res. 2018 Jan;64:30-33. doi: 10.1016/j.leukres.2017.11.004. Epub 2017 Nov 11.
Inhibition of WEE1 is emerging as a promising chemosensitization strategy in many cancers including acute leukemia. Our lab and others have demonstrated that a small-molecule inhibitor of WEE1, AZD1775, sensitizes acute leukemia cells to cytarabine; however, a mechanism of combinatorial activity has remained elusive. Thus, we sought to determine the relative contribution of WEE1 targets CDK1 and CDK2 to the combinatorial activity of AZD1775 and cytarabine. To accomplish this, we expressed "WEE1 resistant" CDK1 (CDK1-AF) and CDK2 (CDK2-AF) constructs in a T-ALL cell line. Expression of CDK1/2-AF together, but neither alone, enhanced the anti-proliferative effects, DNA damage and apoptosis induced by cytarabine. Furthermore, pharmacologic inhibition of CDK1 alone or CDK1 and CDK2 together reduced the combinatorial activity of AZD1775 and cytarabine. Thus, increased activity of both CDK1 and CDK2 in response to WEE1 inhibition is necessary for the combinatorial activity of AZD1775 and cytarabine. This suggests the role of WEE1 in cells with accumulated DNA damage extends beyond regulation of CDK1 and the G2/M checkpoint and highlights the importance of WEE1 in mediating progression through the cell cycle.
在包括急性白血病在内的许多癌症中，抑制WEE1正成为一种有前景的化学增敏策略。我们实验室及其他团队已证明，WEE1的小分子抑制剂AZD1775可使急性白血病细胞对阿糖胞苷敏感；然而，联合作用机制仍不清楚。因此，我们试图确定WEE1的靶点CDK1和CDK2对AZD1775与阿糖胞苷联合活性的相对贡献。为实现这一目标，我们在一个T-ALL细胞系中表达了“WEE1抗性”的CDK1（CDK1-AF）和CDK2（CDK2-AF）构建体。共同表达CDK1/2-AF可增强阿糖胞苷诱导的抗增殖作用、DNA损伤和细胞凋亡，单独表达则无此作用。此外，单独抑制CDK1或同时抑制CDK1和CDK2可降低AZD1775与阿糖胞苷的联合活性。因此，WEE1抑制后CDK1和CDK2活性增加对于AZD1775与阿糖胞苷的联合活性是必要的。这表明WEE1在DNA损伤积累的细胞中的作用超出了对CDK1和G2/M期检查点的调控，突出了WEE1在介导细胞周期进程中的重要性。
