Structural Genomics Consortium, Nuffield Department of Medicine , University of Oxford , Oxford , United Kingdom.
Target Discovery Institute, Nuffield Department of Medicine , University of Oxford , Oxford , United Kingdom.
ACS Chem Biol. 2018 Oct 19;13(10):2849-2854. doi: 10.1021/acschembio.8b00665. Epub 2018 Sep 19.
Targeting the protein-protein interaction between p53 and MDM2/MDMX (MDM4) represents an attractive anticancer strategy for the treatment of p53-competent tumors. Several selective and potent MDM2 inhibitors have been developed and entered the clinic; however, the repertoire of MDMX antagonists is still limited. The arylmethylidenepyrazolinone SJ-172550 has been reported as a selective MDMX antagonist; yet, uncertainties about its mechanism of action have raised doubts about its use as a chemical probe. Here, we show that, in addition to its unclear mode of action, SJ-172550 is unstable in aqueous buffers, giving rise to side products of unknown biological activity. Using an SJ-172550-derived affinity probe, we observed promiscuous binding to cellular proteins whereas cellular thermal shift assays did not reveal a stabilizing effect on MDMX. Overall, our results raise further questions about the interpretation of data using SJ-172550 and related compounds to investigate cellular phenotypes.
靶向 p53 与 MDM2/MDMX（MDM4）之间的蛋白-蛋白相互作用代表了一种有吸引力的抗癌策略，可用于治疗 p53 功能正常的肿瘤。已经开发出几种选择性和有效的 MDM2 抑制剂并进入临床；然而，MDMX 拮抗剂的种类仍然有限。芳甲烯基吡唑啉酮 SJ-172550 已被报道为一种选择性的 MDMX 拮抗剂；然而，由于其作用机制存在不确定性，人们对其作为化学探针的使用产生了怀疑。在这里，我们表明，除了作用机制不明确之外，SJ-172550 在水缓冲液中不稳定，会产生具有未知生物学活性的副产物。使用源自 SJ-172550 的亲和探针，我们观察到与细胞蛋白的混杂结合，而细胞热转移测定并未显示对 MDMX 的稳定作用。总的来说，我们的结果进一步质疑了使用 SJ-172550 和相关化合物来研究细胞表型时对数据的解释。
