Monitoring Drug Target Engagement in Cells and Tissues Using the Cellular Thermal Shift Assay

Drug Targeting Drug efficacy depends on the extent of binding to a cellular target (often a protein) with adverse effects caused by excessive target binding or by off-target binding. Engagement of a target protein inside cells is influenced by the effective drug concentration and by factors that regulate the protein conformation, making it difficult to predict efficacy based on in vitro affinity studies. Martinez Molina et al. (p. 84 ) took advantage of the shift in protein thermal stability caused by drug binding to directly monitor target protein-drug interactions in cells. The method was used to monitor drug target engagement in cancer cells and in mouse livers and kidneys.