Data from Small-molecule inhibition of Wee1 kinase by MK-1775 selectively sensitizes p53-deficient tumor cells to DNA-damaging agents

Abstract

<div>Abstract<p>Wee1 is a tyrosine kinase that phosphorylates and inactivates CDC2 and is involved in G<sub>2</sub> checkpoint signaling. Because p53 is a key regulator in the G<sub>1</sub> checkpoint, p53-deficient tumors rely only on the G<sub>2</sub> checkpoint after DNA damage. Hence, such tumors are selectively sensitized to DNA-damaging agents by Wee1 inhibition. Here, we report the discovery of a potent and selective small-molecule inhibitor of Wee1 kinase, MK-1775. This compound inhibits phosphorylation of CDC2 at Tyr15 (CDC2Y15), a direct substrate of Wee1 kinase in cells. MK-1775 abrogates G<sub>2</sub> DNA damage checkpoint, leading to apoptosis in combination with DNA-damaging chemotherapeutic agents such as gemcitabine, carboplatin, and cisplatin selectively in p53-deficient cells. <i>In vivo</i>, MK-1775 potentiates tumor growth inhibition by these agents, and cotreatment does not significantly increase toxicity. The enhancement of antitumor effect by MK-1775 was well correlated with inhibition of CDC2Y15 phosphorylation in tumor tissue and skin hair follicles. Our data indicate that Wee1 inhibition provides a new approach for treatment of multiple human malignancies. [Mol Cancer Ther 2009;8(11):2992–3000]</p></div>

Development of Cell Permeable NanoBRET Probes for the Measurement of PLK1 Target Engagement in Live Cells

“…To further demonstrate the utility of the PLK1 NanoBRET assay we profiled adavosertib (MK-1775/AZD1775), a WEE1 kinase inhibitor in clinical development for treatment of pancreatic cancer whose kinase selectivity has been the subject of debate in the literature [13,22,23]. In the WEE1 NanoBRET assay using the K10 tracer [24] adavosertib demonstrated an IC50 = 17 nM, which is in agreement with the results of inhibition of substrate phosphorylation in cells [23].…”

“…inhibitor [22] but was subsequently described as a dual WEE1/PLK1 inhibitor on the basis of chemical proteomic and biochemical enzyme inhibition assays [13]. A more recent report suggested that adavosertib was a selective WEE1 inhibitor in cells at clinically relevant doses by profiling the phosphorylation of downstream substrates using immunoblots [23].…”