Intraoperative imaging of hepatic cancers using γ-glutamyltranspeptidase-specific fluorophore enabling real-time identification and estimation of recurrence

Abstract

γ-Glutamyltranspeptidase (GGT) is upregulated in a variety of human cancers including primary and secondary hepatic tumors. This motivated us to use γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), a novel fluorophore emitting light at around 520 nm following enzymatic reaction with GGT, as a tool for the intraoperative identification of hepatic tumors. gGlu-HMRG was topically applied to 103 freshly resected hepatic specimens. Fluorescence imaging using gGlu-HMRG identified hepatic tumors with the sensitivity/specificity of 48%/96% for hepatocellular carcinoma, 100%/100% for intrahepatic cholangiocarcinoma, and 87%/100% for colorectal liver metastasis. High gGlu-HMRG fluorescence intensity was positively associated with the incidence of microscopic vascular invasion in HCC and the risk of early postoperative recurrence in CRLM. These results suggest that gGlu-HMRG imaging could not only be a useful intraoperative navigation tool but also provide information related to postoperative disease recurrence.

Fluorescence‐guided surgery for liver tumors

“…Besides the current dissemination of ICG‐based imaging techniques, 5‐aminolevulinic acid and other cancer‐specific fluorophores have also been developed to enhance the accuracy of fluorescence imaging for identification of liver tumors. Among them, we have developed a gamma‐glutamyltranspeptidase‐specific fluorescence probe, which enables real‐time visualization of adenocarcinoma foci in the hepatic specimens and prediction of postoperative recurrence of CRLM …”

In vivo detection of γ-glutamyl-transferase up-regulation in glioma using hyperpolarized γ-glutamyl-[1-13C]glycine

“…After GGT removes the glutamyl group from GSH, cysteinylglycine is cleaved by an extracellular dipeptidase to the constituent amino acids cysteine and glycine, and the released amino acids are transported into the cell via dedicated transporters. We did not observe any consistent asymmetry in the lineshape of glycine peak, however, considering our line width (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and the relatively long T 1 of glycine (45 s at 9.4T 31 ) we cannot rule out that some of the HP γ-glutamyl-[1-13 C]glycine is intracellular. Importantly however, the precise compartmental localization of glycine would not be expected to affect our conclusions regarding its association with tumor.…”

“…The high level of expression of GGT in glioblastoma and its presence on the outer cell membrane make it an attractive molecular target for assessing redox and imaging GBMs. Non-invasive methods of monitoring GGT using radiolabeled or fluorescence probes have been previously described 18,[20][21][22] . However radiolabeled agents do not provide information regarding enzyme activity as they accumulate at the tumor site by diffusion, and the utility of fluorescent probes is limited by the depth of fluorescent light penetration through the skull.…”

Development of Novel Fluorogenic Probes for Realizing Rapid Intraoperative Multi-color Imaging of Tiny Tumors

“…Reaction was performed in 0.1 M sodium phosphate buffer (pH 7.4) at 37 °C. Excitation wavelength was 501 nm (Miyata et al 2017) cancers. For example, breast cancer could be visualized regardless of its types like invasive/non-invasive or ER and HER2(+)/(−) with high specificity and sensitivity, both exceeded 90% (Ueo et al 2015), and metastases in sentinel lymph nodes could be examined within a few minutes with high negative predictive values (>99%) (Shinden et al 2016).…”