In drug discovery, selective binding of the compound to the right target is important for the drug to be both effective and safe. To achieve this, the drug must be present at the site of action and occupy the intended target with high specificity. The attrition in phase 1 studies is often attributed to off-target induced toxicities as the dose is increased. Therefore, it is equally important to understand the selectivity profile as verifying compound interaction with the intended target in the cell. CETSA® Explore is a powerful method for target identification and, in addition, assessment of the selectivity profile of the compound series. Regular use of CETSA® Explore to assess selectivity, could flag safety issues and allow them to be addressed early in the drug discovery process. Conventional screening methods, e.g., using target panels, are not sufficient to fully profile the selectivity since drug candidates usually have multiple physiological targets far beyond the limited scope of these panels. CETSA® Explore can effectively assess both on- and off-target protein binding through unbiased proteome-wide protein profiling and allows researchers to determine the impact on both individual proteins as well as on entire pathways affected by the compound.
In a recent publication, CETSA® Explore was used to profile the pan–kinase inhibitor staurosporine. Included in this study was a correlation between the XC50 values derived from the CETSA® experiment with previously reported Kd values from a competitive binding assay. The study clearly showed a good correlation between the binding affinity and the effect of the compound on the thermal stability of the proteins.
Chernobrovkin AL, Legnqvist J, et al. In-depth characterization of Staurosporin induced proteome thermal stability changes. (2020) DOI:https://doi.org/10.1101/2020.03.13.990606
Chernobrovkin AL, Cázares-Körner C, et al. A tale of two tails – efficient profiling of protein degraders by specific functional and target engagement readouts. (2020) DOI: https://doi.org/10.1177/2472555220984372