Department of Oncology, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA.
Cancer Cell Int. 2012 Nov 13;12(1):45. doi: 10.1186/1475-2867-12-45.
Inhibition of kinases involved in the DNA damage response sensitizes cells to genotoxic agents by abrogating checkpoint-induced cell cycle arrest. CHK1 and WEE1 act in a pathway upstream of CDK1 to inhibit cell cycle progression in response to damaged DNA. Therapeutic targeting of either CHK1 or WEE1, in combination with chemotherapy, is under clinical evaluation. These studies examine the overlap and potential for synergy when CHK1 and WEE1 are inhibited in cancer cell models.
Small molecules MK-8776 and MK-1775 were used to selectively and potently inhibit CHK1 and WEE1, respectively.
In vitro, the combination of MK-8776 and MK-1775 induces up to 50-fold more DNA damage than either MK-8776 or MK-1775 alone at a fixed concentration. This requires aberrant cyclin-dependent kinase activity but does not appear to be dependent on p53 status alone. Furthermore, DNA damage takes place primarily in S-phase cells, implying disrupted DNA replication. When dosed together, the combination of MK-8776 and MK-1775 induced more intense and more durable DNA damage as well as anti-tumor efficacy than either MK-8776 or MK-1775 dosed alone. DNA damage induced by the combination was detected in up to 40% of cells in a treated xenograft tumor model.
These results highlight the roles of WEE1 and CHK1 in maintaining genomic integrity. Importantly, the strong synergy observed upon inhibition of both kinases suggests unique yet complimentary anti-tumor effects of WEE1 and CHK1 inhibition. This demonstration of DNA double strand breaks in the absence of a DNA damaging chemotherapeutic provides preclinical rationale for combining WEE1 and CHK1 inhibitors as a cancer treatment regimen.
抑制参与 DNA 损伤反应的激酶通过消除检查点诱导的细胞周期停滞来使细胞对遗传毒性药物敏感。CHK1 和 WEE1 在 CDK1 的上游途径中起作用，以响应受损 DNA 抑制细胞周期进程。CHK1 或 WEE1 的治疗靶向与化疗联合，正在临床评估中。这些研究检查了当在癌细胞模型中抑制 CHK1 和 WEE1 时的重叠和潜在协同作用。
小分子 MK-8776 和 MK-1775 分别用于选择性和有效地抑制 CHK1 和 WEE1。
在体外，MK-8776 和 MK-1775 的组合在固定浓度下比单独使用 MK-8776 或 MK-1775 诱导多达 50 倍的更多 DNA 损伤。这需要异常的细胞周期蛋白依赖性激酶活性，但似乎不单独依赖于 p53 状态。此外，DNA 损伤主要发生在 S 期细胞中，意味着 DNA 复制受到破坏。当一起给药时，MK-8776 和 MK-1775 的组合诱导比单独使用 MK-8776 或 MK-1775 更强和更持久的 DNA 损伤以及抗肿瘤功效。在治疗的异种移植肿瘤模型中，多达 40%的细胞中检测到组合诱导的 DNA 损伤。
这些结果突出了 WEE1 和 CHK1 在维持基因组完整性中的作用。重要的是，在抑制两种激酶时观察到的强烈协同作用表明 WEE1 和 CHK1 抑制具有独特但互补的抗肿瘤作用。在没有 DNA 损伤化疗药物的情况下观察到 DNA 双链断裂，为将 WEE1 和 CHK1 抑制剂联合作为癌症治疗方案提供了临床前依据。
