Abstract 2019: Photoimmunotherapy with an anti-EGFR antibody conjugated to an IRDye700 results in extensive and rapid cell death in vitro and in vivo in human pancreatic cancer cell lines

Photoimmunotherapy (PIT) of cancer utilizes tumor-specific monoclonal antibodies conjugated to a photosensitizer phthalocyanine dye IR700 which becomes cytotoxic upon irradiation with near infrared light. In this study, we aimed to evaluate the efficacy of PIT on human pancreatic cancer cells in vitro and in vivo in a nude mouse model. An in vitro cytotoxicity assay was used to determine cell death following treatment with PIT for Panc-1, MiaPaCa2, and BxPC-3 human pancreatic cancer cells. For in vivo determination of PIT efficacy, nude mice were implanted with BxPC-3 pancreatic tumors expressing green fluorescent protein (GFP). After tumor engraftment, the mice were divided into two groups: treatment with anti-EGFR-IR700 + 690 nm laser and treatment with 690 nm laser only. Anti-EGFR-IR700 (100 μg) was administered to the treatment group via tail vein injection 24 hours prior to therapy. Tumors were then exposed and treated with phototherapy at an intensity of 150 mW/cm2 for 30 minutes. Whole body imaging was done using an OV-100 small animal imaging system. Anti-EGFR-IR700 antibody bound to the BxPC3 cells to a high degree based on image co-localization. Anti-EGFR-IR700 caused extensive cancer cell killing after light activation compared to control cells in cytotoxicity assays. In the mouse experiments, the treatment group had significantly smaller tumors as measured by GFP than the control after just 96 hours. The present results indicate the high potential of PIT for pancreatic cancer therapy. Citation Format: Nzola de Magalhaes, Takashi Murakami, Roger Heim, Lew Makings, Miguel Garcia-Guzman, Hisataka Kobayashi, Robert M. Hoffman, Michael Bouvet. Photoimmunotherapy with an anti-EGFR antibody conjugated to an IRDye700 results in extensive and rapid cell death in vitro and in vivo in human pancreatic cancer cell lines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2019. doi:10.1158/1538-7445.AM2015-2019