Evaluation of Early Therapeutic Effects after Near-Infrared Photoimmunotherapy (NIR-PIT) Using Luciferase-Luciferin Photon-Counting and Fluorescence Imaging

Yasuhiro Maruoka, Tadanobu Nagaya, Yuko Nakamura, Kazuhide Sato, Fusa Ogata, Shuhei Okuyama, Peter L. Choyke, Hisataka Kobayashi

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)

Abstract

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed cancer treatment that induces highly selective immunogenic cell death. It is based on an antibody-photoabsorber conjugate (APC) that is activated by NIR light. The purpose of this study was to investigate the effects of NIR-PIT as measured by luciferase-luciferin photon-counting and fluorescence imaging. Six days after subcutaneous injection of A431-luc-GFP cells tumors formed in a xenograft mouse model. The EGFR-targeting antibody, panitumumab, was conjugated to the photoabsorber, IRDye-700DX (pan-IR700), and was intravenously administered to tumor-bearing mice. Serial luciferase-luciferin photon-counting images and both green fluorescent protein (GFP) and IR700 fluorescence images were obtained from the same mice before and after NIR-PIT treatment (0, 10, 20, 30 min (early phase), and 24, 48 h (late phase) after NIR light exposure). Optical signal intensities were compared for each modality. IR700 fluorescence and luciferase-luciferin photon-counting images showed decreased intensities in both the early and late phases after NIR-PIT (p < 0.01). On the other hand, GFP fluorescence images showed decreased intensities only in the late phase (p < 0.01). In the early phase, GFP fluorescence images showed smaller intensity reductions compared to IR700 fluorescence and luciferase-luciferin photon-counting (p < 0.01), while in the late phase, IR700 fluorescence showed smaller intensity reductions than luciferase-luciferin photon-counting and GFP fluorescence (p < 0.05), due to redistribution of pan-IR700 within the tumor bed. In conclusion, luciferase-luciferin photon-counting imaging is suitable to evaluate early phase NIR-PIT effects, while both luciferase-luciferin photon-counting and GFP reflected later phase effects.

Original languageEnglish
Pages (from-to)4628-4635
Number of pages8
JournalMolecular pharmaceutics
Volume14
Issue number12
DOIs
Publication statusPublished - Dec 4 2017
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery

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