Rapid Cancer Fluorescence Imaging Using A γ-Glutamyltranspeptidase-Specific Probe For Primary Lung Cancer

Abstract

BACKGROUND: We set out to examine the activity of γ-glutamyltranspeptidase (GGT) in lung cancer and the validity of γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) for intraoperative imaging of primary lung cancer. METHODS: GGT activities and mRNA expression levels of GGT1 (one of the GGT subtypes) in five human lung cancer cell lines were examined by fluorescence imaging and quantitative reverse transcription polymerase chain reaction. In vivo imaging of an orthotopic A549 xenograft model in nude mice was performed to confirm its applicability to intraoperative imaging. Furthermore, ex vivo imaging of 73 specimens from lung cancer patients were performed and analyzed to calculate the sensitivity/specificity of gGlu-HMRG for lung cancer diagnosis. RESULTS: GGT activities and mRNA expression levels of GGT1 are diverse depending on cell type; A549, H441, and H460 showed relatively high GGT activities and expression levels, whereas H82 and H226 showed lower values. In the in vivo mouse model study, tiny pleural dissemination and hilar/mediastinal lymph node metastasis (less than 1 mm in diameter) were clearly detected 15 minutes after topical application of gGlu-HMRG. In the ex vivo study of specimens from patients, the sensitivity and specificity of gGlu-HMRG were calculated to be 43.8% (32/73) and 84.9% (62/73), respectively. When limited to female patients, never smokers, and adenocarcinomas, these values were 78.9% (15/19) and 73.7% (14/19), respectively. CONCLUSIONS: Although GGT activity of lung cancer cells vary, gGlu-HMRG can serve as an intraoperative imaging tool to detect small foci of lung cancer when such cells have sufficient GGT activity.

Rapid detection of papillary thyroid carcinoma by fluorescence imaging using a γ-glutamyltranspeptidase-specific probe: a pilot study

“…As GGT is overexpressed on the membranes of various cancer cells, gGlu-HMRG has been reported as a tool to detect breast cancer [ 12 ], lung cancer [ 9 ], colorectal tumors [ 10 ], head and neck squamous cell carcinoma [ 7 ], and prostate cancer [ 13 ]. The sensitivity and specificity of gGlu-HMRG in lung cancer detection are 43.8 and 84.9%, respectively [ 9 ]. gGlu-HMRG also reportedly enabled rapid fluorescence imaging of 54 and 76% of colorectal adenomas and carcinomas, respectively [ 10 ].…”

“…Small tumors are reportedly rapidly detectable by fluorescence imaging in vivo [ 23 – 28 ]. Several studies have reported that GGT is highly expressed in cancer cell membranes, as determined by immunohistochemical methods [ 7 , 9 ]. In this study, 14 thyroid cancer samples among 16 cases were positive for GGT in the cell membranes; in contrast, cases involving non-cancerous or inflammatory lesions were negative.…”

“…Two cell lines were prepared with high and low GGT expression. The high GGT expression cell line was A549, established from human lung adenocarcinoma and reported as a positive control for gGlu-HMRG [ 9 ], and the low GGT expression cell lone was SW782, a noncancerous line of human pre-adipocytes.…”

“…The brightness of the fluorescent agent is grossly confirmed, and green fluorescence indicates the presence of cancer [ 12 ]. Until the development of this method, there was no technique capable of visualizing cancer during surgery in such a short time; furthermore, this detection method using gGlu-HMRG is reported to be very simple [ 4 , 7 , 9 ]. No study has examined the use of the GGT-gGlu-HMRG detection method on primary human thyroid tumors.…”

Untitled

“…In this study it was observed that GGT1 was significantly expressed in breast cancer when compared with the control. The expression of tumor tissue GGT1 has also been shown in various cancers such as prostate (Kawakami et al 2017), epithelial (Lukic et al 2016), lung (Hino et al 2016), colorectal (Palaniappan et al 2016), overian (Mahata 2006), liver (Pavesi et al 1989), and breast (Banneau et al 2010).…”