Law Samuel M, Zheng Jie J
Stein Eye Institute, Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
iScience. 2022 Mar 25;25(4):104159. doi: 10.1016/j.isci.2022.104159. eCollection 2022 Apr 15.
Wnt signaling pathways have been extensively studied in the context of several diseases, including cancer, coronary artery disease, and age-related disorders. β-Catenin plays a central role in the most studied Wnt pathways, the Wnt/β-catenin signaling pathway, commonly referred to as the canonical Wnt signaling pathway. β-catenin is a substrate of glycogen synthase kinase 3β (GSK-3β), and the phosphorylated β-catenin by GSK-3β can be degraded by the proteasome through ubiquitination. Thus, GSK-3β inhibitors have become a widely used chemical biology tool to study the canonical Wnt signaling pathway. Among the varied GSK-3β inhibitors, a compound known as CHIR-99021 is one of the most widely used. Although these inhibitors contribute greatly to our understanding of the canonical Wnt pathway, certain pitfalls associated with such an approach may have been overlooked. In many published studies, micromolar concentrations of CHIR-99021 are used to activate the canonical Wnt pathway. Although CHIR-99021 is a specific GSK-3β inhibitor, it specifically inhibits the kinase at the nanomolar level. Therefore, caution is required when micromolar levels of CHIR-99021 are used for the purpose of activating the canonical Wnt signaling pathway.
Wnt信号通路已在包括癌症、冠状动脉疾病和年龄相关疾病在内的多种疾病背景下得到广泛研究。β-连环蛋白在研究最多的Wnt通路即Wnt/β-连环蛋白信号通路（通常称为经典Wnt信号通路）中发挥核心作用。β-连环蛋白是糖原合酶激酶3β（GSK-3β）的底物，GSK-3β磷酸化的β-连环蛋白可通过泛素化被蛋白酶体降解。因此，GSK-3β抑制剂已成为研究经典Wnt信号通路广泛使用的化学生物学工具。在各种GSK-3β抑制剂中，一种名为CHIR-99021的化合物是使用最广泛的之一。尽管这些抑制剂对我们理解经典Wnt通路有很大帮助，但这种方法相关的某些陷阱可能被忽视了。在许多已发表的研究中，使用微摩尔浓度的CHIR-99021来激活经典Wnt通路。尽管CHIR-99021是一种特异性GSK-3β抑制剂，但它在纳摩尔水平特异性抑制该激酶。因此，当使用微摩尔水平的CHIR-99021来激活经典Wnt信号通路时需要谨慎。
