A novel triarylboron based ratiometric fluorescent probe for in vivo targeting and specific imaging of cancer cells expressing abnormal concentration of GGT

Abnormal expression of gamma-glutamyltranspeptidase (GGT) in living organisms is closely associated with tumor-igenesis. However, few reported fluorescence probes can specifically respond to abnormal concentration of GGT. Here, by functionalizing triarylboron moiety with three GGT-specific substrate (GSH) units, a novel fluorescence probe, TAB-3-GSH, was developed for detecting GGT. The results showed that TAB-3-GSH selectively responds to abnormally high levels of GGT (100-1000 U/L) rather than to normal GGT levels ( < 100 U/L) with ratiometric readout, since the amide linkage can be further hydrolyzed under high GGT levels. TAB-3-GSH was also capable of differentiating GGT-overexpressing ovarian cancer cells from normal cells, because of an improvement in the probe's cell membrane permeability upon reaction with GGT. Moreover, the probe could achieve selective imaging of SKOV-3 tumor site in xenograft mice model. Thus, TAB-3-GSH is a promising probe for tumor targeting in vivo.