Premise and peril of Wnt signaling activation through GSK-3β inhibition

Wnt signaling pathways have been extensively studied in the context of several diseases, including cancer, coronary artery disease, and age-related disorders. beta-Catenin plays a central role in the most studied Wnt pathways, the Wnt/beta-catenin signaling pathway, commonly referred to as the canonical Wnt signaling pathway. beta-catenin is a substrate of glycogen synthase kinase 3 beta (GSK-3 beta), and the phosphorylated beta-catenin by GSK-3 beta can be degraded by the proteasome through ubiquitination. Thus, GSK-3 beta inhibitors have become a widely used chemical biology tool to study the canonical Wnt signaling pathway. Among the varied GSK-3 beta 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-3 beta 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.

Automated summary

Wnt signaling pathways play a significant role in various diseases. β-catenin is central to the canonical Wnt signaling pathway. CHIR-99021, a GSK-3β inhibitor, is widely used for studying this pathway. However, caution is needed when using CHIR-99021 at certain concentrations.