American Association for Cancer Research
15357163mct150644-sup-153599_1_video_3199960_nwswvv.wmv (8.78 MB)

Morphological changes induced immediately after Tra-IR700-mediated PIT from Trastuzumab-Based Photoimmunotherapy Integrated with Viral HER2 Transduction Inhibits Peritoneally Disseminated HER2-Negative Cancer

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posted on 2023-04-03, 14:43 authored by Michihiro Ishida, Shunsuke Kagawa, Kyoko Shimoyama, Kiyoto Takehara, Kazuhiro Noma, Shunsuke Tanabe, Yasuhiro Shirakawa, Hiroshi Tazawa, Hisataka Kobayashi, Toshiyoshi Fujiwara

Morphological changes induced immediately after Tra-IR700-mediated PIT in HER2-ECD-transduced gastric cancer cells captured as a time-lapse movie. The cells, which were treated with the integration of Ad/HER2-ECD and Tra-IR700-mediated PIT, shrunk without proliferation. Tra-IR700-mediated PIT cells and control adenovirus (Ad/GFP)-infected cells survived without any phototoxic or virus-toxic effects.


Ministry of Education Culture, Sports, Science and Technology, Japan

Ministry of Health, Labor and Welfare, Japan

National Institutes of Health, National Cancer Institute, Center for Cancer Research.



Peritoneal dissemination is the most frequent metastasis in gastric cancer and is associated with poor prognosis. The lack of particular target antigens in gastric cancer other than HER2 has hampered the development of treatments for peritoneal dissemination of gastric cancer. We hypothesized that HER2-extracellular domain (HER2-ECD) gene transduction combined with trastuzumab-based photoimmunotherapy (PIT) might provide excellent and selective antitumor effects for peritoneal dissemination of gastric cancer. In vitro, adenovirus/HER2-ECD (Ad/HER2-ECD) efficiently transduced HER2-ECD into HER2-negative gastric cancer cells. Trastuzumab-IR700 (Tra-IR700)–mediated PIT induced selective cell death of HER2-ECD–transduced tumor cells. Ad/HER2-ECD also induced homogenous expression of HER2 in heterogeneous gastric cancer cells, resulting in uniform sensitivity of the cells to Tra-IR700–mediated PIT. Anti-HER2 PIT integrated with adenoviral HER2-ECD gene transfer was applied in mice bearing peritoneal dissemination of HER2-negative gastric cancer. Intraperitoneal administration of Ad/HER2-ECD and Tra-IR700 with PIT inhibited peritoneal metastasis and prolonged the survival of mice bearing MKN45. Furthermore, minimal side effects allowed the integrated therapy to be used repeatedly, providing better control of peritoneal dissemination. In conclusion, the novel therapy of molecular-targeted PIT integrated with gene transfer technology is a promising approach for the treatment of peritoneal dissemination in gastric cancer. Mol Cancer Ther; 15(3); 402–11. ©2016 AACR.

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