Abstract

CETSA® Cellular Thermal Shift assay is a label-free well-proven technology used to assess protein-ligand binding in cells. Coupled with mass spectrometry as a readout, CETSA® EXPLORE (or PISA), provides direct detection of compound binding via ligand-induced changes in protein thermal stability in an unbiased proteome-wide setting. This technology allows the identification of compound primary targets and off-targets as well as downstream affected targets. 

By systematically analyzing target engagement profiles of more than 400 approved drugs and probes in three representative cell lines, we study primary targets, downstream hits, and their environment of interactions in the relevant cell context.  Bioinformatic efforts examine which signatures connect with specific phenotypic responses, which proteins are frequent shifters, and patterns of the mode of action, to generate a library of cellular drug responses, named Target Engagement Altas (TEA). This comprehensive study can help to understand common patterns of known safety issues and dissect these patterns across three cell lines to include the biology dimension. We present here some examples of cellular discrepancies in drug response patterns. Studying how different chemical motifs have an impact on the CETSA® fingerprints can in turn assist in SAR studies in the context of live cells proteome.