Expanding the toolbox for MAP2K3 inhibitors

MAP2K3 is a kinase in the intermediate steps of Mitogen-Activated Protein Kinase (MAPK) pathway1. Upon activation, it activates MAP kinases which phosphorylate other proteins. MAP2K3 activity was shown in different diseases, especially in cancer2. Despite the importance of MAP2K3 in different pathologies, to date, there are only few small-molecule inhibitors reported. In order to facilitate the search for new molecules targeting this protein we developed a non-radiometric (in vitro) assay and a Target Engagement (in cell) assay. We screened, in vitro, a library of 384 known kinase inhibitors at 1µM and found chemical similarities among the hits. Then, we generated a small library of analogues to understand more about the structure-activity relationship, and the most potent analogue (SV161) was submitted to an in-cell target engagement assay (NanoBRET) and a in-house selectivity panel. Here we presented and validated tools so far absent in the literature to further study inhibitors for MAP2K3.