@article {Jensen128, author = {Bettina M. Jensen and Michael A. Beaven and Shoko Iwaki and Dean D. Metcalfe and Alasdair M. Gilfillan}, title = {Concurrent Inhibition of Kit- and FcϵRI-Mediated Signaling: Coordinated Suppression of Mast Cell Activation}, volume = {324}, number = {1}, pages = {128--138}, year = {2008}, doi = {10.1124/jpet.107.125237}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Although primarily required for the growth, differentiation, and survival of mast cells, Kit ligand (stem cell factor) is also required for optimal antigen-mediated mast cell activation. Therefore, concurrent inhibition of Kit- and FcϵRI-mediated signaling would be an attractive approach for targeting mast cell-driven allergic reactions. To explore this concept, we examined the effects of hypothemycin, a molecule that we identified as having such properties, in human and mouse mast cells. Hypothemycin blocked Kit activation and Kit-mediated mast cell adhesion in a similar manner to the well characterized Kit inhibitor imatinib mesylate (imatinib). In contrast to imatinib, however, hypothemycin also effectively inhibited FcϵRI-mediated degranulation and cytokine production in addition to the potentiation of these responses via Kit. The effect of hypothemycin on Kit-mediated responses could be explained by its inhibition of Kit kinase activity, whereas the inhibitory effects on FcϵRI-dependent signaling were at the level of Btk activation. Because hypothemycin also significantly reduced the mouse passive cutaneous anaphylaxis response in vivo, these data provide proof of principle for a coordinated approach for the suppression of mast cell activation and provide a rationale for the development of compounds with a similar therapeutic profile. The American Society for Pharmacology and Experimental Therapeutics}, issn = {0022-3565}, URL = {https://jpet.aspetjournals.org/content/324/1/128}, eprint = {https://jpet.aspetjournals.org/content/324/1/128.full.pdf}, journal = {Journal of Pharmacology and Experimental Therapeutics} }