Imaging γ-Glutamyltranspeptidase for tumor identification and resection guidance via enzyme-triggered fluorescent probe

Development of high selectivity, accurate targeted and noninvasive fluorescent probe for monitoring specific enzyme activity associated with the tumor is urgent needed for early diagnosis of cancer and clinical fluorescence interventional resection guidance treatment. Owing to the invasion of malignant tumor cells, tumor cells are mixed with normal cells in the actual tumor location, which make it quite difficult for clinician to diagnose early diagnosis of tumor as well as resection of tumor. To overcome aforementioned obstacle, herein, an ingenious enzyme-activated one and two-photon fluorescent probe TCF-GGT was constructed and synthesized including γ-GGT enzyme specific identification site and far-red fluorophore for imaging. Under simulative physiological condition, probe TCF-GGT demonstrated high selectivity, sensitivity (DL 0.014 mU/mL), rapid response (Te 14 min) for the detection of γ-GGT enzyme. By virtue of its biocompatibility, probe was employed for the identification of ovarian cancer cells (A2780 cells) from normal cells (NIH-3T3 cells), particularly in mixed cultivation dish (simulate the actual environment of tumor) through 2D&3D fluorescence imaging with “dual” mark (Nucleic acid labeling used by Hoechst 33342 dye and γ-GGT enzyme labeling used by probe TCF-GGT) for the first time. Probe TCF-GGT could be visualize endogenous γ-GGT activity in HepG-2 cells and zebrafish on the two-photon confocal platform, which is conduce to estimate the inhibitor of γ-GGT enzyme in vivo. Through NaBu (a potential anticancer drug) stimulation, the changes of γ-GGT activity were observed in living MCF-7 cells by using this probe. More importantly, the deep tissue penetration ability of far-red fluorescence allowed the two-photon fluorescent probe TCF-GGT to real-time track γ-GGT activity in tissue slices and tumor xenotransplantation model of mice by the tail vein injection, which showed that this enzyme-triggered fluorogenic probe would be a potential tool for preclinical applications of tumor resection.