Development of an Activatable Fluorescent Probe for Prostate Cancer Imaging.

Technology to visualize small prostate cancers is urgently needed because of the difficulty of discriminating prostate cancer from normal tissue with the naked eye, and a fluorescence imaging method would be advantageous. Here, we describe the design and synthesis of a fluorogenic probe (Ac-KQLR-HMRG) that is activated by hepsin and matriptase (proteases over-expressed in prostate cancer). Ac-KQLR-HMRG exhibited significant turn-on fluorogenicity in the presence of hepsin (180-fold) and matriptase (80-fold) and allowed specific fluorescence imaging of various prostate cancer cell line in vitro. In addition, the probe enabled rapid imaging (within 1-10 min) of small prostate cancer nodules in mouse models of disseminated peritoneal tumor and orthotopic tumor.