Bioluminescent Probe for Monitoring Endogenous Fibroblast Activation Protein-Alpha

Fibroblast activation protein-alpha (FAP), as a crucial member of cell surface glycoprotein, highly expresses in reactive fibroblasts of tumors and several fibrosis diseases. It is a potential target for drug design and also reported as a prodrug strategy to increase the therapeutic window of some anticancer agents. In this work, we developed the first bioluminogenic probe for FAP with a limit-of-detection of 0.254 ng/mL, which could be applied to evaluate the FAP inhibitors in vitro. The experiments of transgenic mice and tumor-bearing nude mice validated our probe 1 could reflect the endogenous FAP level in vivo. Furthermore, this probe was successfully used to reflect FAP up-regulation in the lung homogenates of the bleomycin-induced idiopathic pulmonary fibrosis mice.