Neocarzilin A is a potent inhibitor of cancer cell motility targeting VAT-1 controlled pathways

The natural product neocarzilin A (NCA) was discovered decades ago and despite its potent cytotoxic effects no mode of action studies were performed up to date. Synthesis of neocarzilins A, B, C and a stereoisomer of NCA provided insights into structural preferences as well as access to probes for functional studies. NCA pertained as the most active member and was not only effective against cell proliferation but also migration, a novel and so far overlooked activity. The potent anti-migratory effects could also be confirmed in an in vivo breast carcinoma mouse model. To decipher the molecular mode of action, we applied chemical proteomics for target discovery and revealed that NCA interrogates 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 absence of anti-proliferative effects.

天然产物新卡唑林A（Neocarzilin A，NCA）于数十年前被发现，尽管其具有强效细胞毒性，但截至目前尚无针对其作用机制的相关研究。通过合成新卡唑林A、B、C以及NCA的一种立体异构体，我们不仅明确了该类化合物的结构偏好性，还获得了可用于功能研究的探针分子。NCA是其中活性最强的成员，其作用不仅涵盖抑制细胞增殖，还可阻断细胞迁移——这是一种此前未被关注的全新活性。其强效的抗迁移活性在小鼠乳腺癌体内模型中得到了验证。为解析其分子作用机制，我们采用化学蛋白质组学开展靶点发现工作，结果显示NCA通过与尚未被充分表征的突触囊泡膜蛋白VAT-1不可逆结合，实现对癌细胞迁移的调控。对该蛋白进行的基因敲除实验验证了这一表型，而下拉实验则证实NCA可与包括踝蛋白-1（Talin-1）在内的关键迁移调控因子所构成的复杂网络发生相互作用。综上，我们提出VAT-1是开发选择性迁移抑制剂的极具潜力的全新靶点，有望在不产生抗增殖活性的前提下降低药物毒性。