A high-throughput screening approach identified a selective pro-caspase-10 probe that can inhibit its activity

Caspases are cysteine proteases that play a critical role in inflammation and apoptosis. Caspases have a functional role in either the intrinsic apoptotic pathway as initiators of apoptosis or in the extrinsic apoptotic pathway as executioners of apoptosis. Caspase-10 has been speculated to play a principal role as an initiator of apoptosis but the absence of adequate tools, i.e. selective probes, have hindered our understanding of this enzyme as well as the other caspases. Here, we engineered a tobacco etch virus (TEV)-cleavable construct that is compatible with high-throughput screening to identify selective caspase-10 inhibitors. We identified a set of promiscuous caspase inhibitors, including pifithrin-µ (PFT), an inhibitor of p53 transcriptional activity, as well as promising selective pro-caspase-10 and TEV protease inhibitors.