Monitoring Target Engagement in Drug Discovery

Application of Wes to the Cellular Thermal Shift Assay

In drug discovery, confirmation of in-cell target engagement is a critical component of the drug development process. Confirming that a drug candidate engages its proposed target in the cell and determining the concentration at which it exerts the desired effect(s) fulfill fundamental criteria for translation to activity and efficacy in its target tissue. Thermal shift assays (TSA) are regularly used by industry and academia to uncover or confirm interactions using purified proteins. Recently, this type of assay has been adapted to a cellular format and is called the cellular thermal shift assay (CETSA). Importantly, by upgrading from a biochemical to a cellular system, biological relevance is preserved.

Dr. Matias Casás Selves, Research Scientist, Drug Discovery Program, Ontario Institute for Cancer Research, developed a CETSA-Wes assay to monitor protein stability during drug discovery. This application note highlights quantitative and reproducible CETSA data generated with ProteinSimple’s Wes™ instrument (CETSA-Wes). This assay verifies drug–target binding, and given its quantitative nature, the half maximal inhibitory concentration (IC₅₀) is also calculated.