Theranostics 2018; 8(9):2313-2328. doi:10.7150/thno.22027

Research Paper

A Novel Theranostic Combination of Near-infrared Fluorescence Imaging and Laser Irradiation Targeting c-KIT for Gastrointestinal Stromal Tumors

Shota Fujimoto1, Naoki Muguruma1, Koichi Okamoto1, Takeshi Kurihara1, Yasushi Sato1, Yoshihiko Miyamoto1, Shinji Kitamura1, Hiroshi Miyamoto1, Takahiro Taguchi2, Koichi Tsuneyama3, Tetsuji Takayama1✉

1. Department of Gastroenterology and Oncology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
2. Division of Human Health & Medical Science, Graduate School of Kuroshio Science, Kochi University, Nankoku, Kochi, Japan
3. Department of Pathology and Laboratory Medicine, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
✉ Corresponding author: Tetsuji Takayama, Department of Gastroenterology and Oncology, Tokushima University Graduate School of Biomedical Sciences, 3-18-15, Kuramoto-cho, Tokushima, 770-8503, Japan. Tel: +81-88-633-7124; Fax: +81-88-633-9235; E-mail: takayama@tokushima-u.ac.jp

This is an open access article distributed under the terms of the Creative Commons Attribution (CC BY-NC) license (https://creativecommons.org/licenses/by-nc/4.0/). See http://ivyspring.com/terms for full terms and conditions.
Citation:
Fujimoto S, Muguruma N, Okamoto K, Kurihara T, Sato Y, Miyamoto Y, Kitamura S, Miyamoto H, Taguchi T, Tsuneyama K, Takayama T. A Novel Theranostic Combination of Near-infrared Fluorescence Imaging and Laser Irradiation Targeting c-KIT for Gastrointestinal Stromal Tumors. Theranostics 2018; 8(9):2313-2328. doi:10.7150/thno.22027. Available from https://www.thno.org/v08p2313.htm

File import instruction

Abstract

It is difficult to distinguish gastrointestinal stromal tumors (GISTs) from other types of submucosal tumors under conventional gastrointestinal endoscopy. We aimed to detect GISTs by molecular fluorescence imaging using a near-infrared (NIR) photosensitizer (IR700)-conjugated anti-c-KIT antibody and to treat GISTs by photoimmunotherapy with NIR irradiation as a non-invasive theranostic procedure. We also investigated the therapeutic mechanisms.

Methods: Human GIST cell lines GIST-T1 and GIST-882M were incubated with IR700-conjugated anti-c-KIT antibody, IR700-12A8, and observed by confocal laser microscopy. Mice with GIST-T1 xenografts or rats with orthotopic xenografts were injected with IR700-12A8 or AF488-conjugated antibody, and observed under IVIS or autofluorescence imaging (AFI) endoscopy. GIST cells were treated with IR700-12A8 and NIR light in vitro and vivo, and cell viability, histology and apoptosis were evaluated.

Results: Strong red fluorescence of IR700-12A8 was observed on the cell membrane of GIST cells and was gradually internalized into the cytoplasm. Tumor-specific accumulation of IR700-12A8 was observed in GIST-T1 xenografts in mice. Under AFI endoscopy, a strong fluorescence signal was observed in orthotopic GIST xenografts in rats through the normal mucosa covering the tumor. The percentage of dead cells significantly increased in a light-dose-dependent manner and both acute necrotic and late apoptotic cell death was observed with annexin/PI staining. Cleaved PARP expression was significantly increased after IR700-12A8-mediated NIR irradiation, which was almost completely reversed by NaN3. All xenograft tumors (7/7) immediately regressed and 4/7 tumors completely disappeared after IR700-12A8-mediated NIR irradiation. Histologic assessment and TUNEL staining revealed apoptosis in the tumors.

Conclusion: NIR fluorescence imaging using IR700-12A8 and subsequent NIR irradiation could be a very effective theranostic technology for GIST, the underlying mechanism of which appears to involve acute necrosis and supposedly late apoptosis induced by singlet oxygen.

Keywords: gastrointestinal stromal tumors (GIST), c-KIT, fluorescence endoscopy, near-infrared photoimmunotherapy