Abstract
The natural product neocarzilin A (NCA) was discovered decades ago, and despite its potent cytotoxic effects no mode of action studies have been performed up to date. Synthesis of neocarzilins A, B, and C and a stereoisomer of NCA provided insights into structural preferences as well as access to probes for functional studies. NCA turned out to be the most active member and was not only effective against cell proliferation but also migration, a novel and so far overlooked activity. To decipher the molecular mode of action, we applied chemical proteomics for target discovery and revealed that NCA targets cancer cell migration via irreversible binding to the largely uncharacterized synaptic vesicle membrane protein VAT-1. A corresponding knockout of the protein confirmed the phenotype, and pull-down studies showed the interaction with an intricate network of key migration mediators such as Talin-1. Overall, we introduce VAT-1 as a promising novel target for the development of selective migration inhibitors with the perspective to limit toxicity in the absence of antiproliferative effects.