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Proceedings Paper

Photochemical internalization (PCI) of bleomycin induces T-cell activation of importance for curative effect and systemic anti-tumor immunity (Conference Presentation)
Author(s): Kristian Berg; Ane Sofie Fremstedal; Anette Weyergang; Jakub Golab; Ole-Jacob Norum

Paper Abstract

Photochemical internalization (PCI) is a technology to enhance intracellular drug delivery by light-induced translocation of endocytosed therapeutics into the cytosol. The aim of this study was to explore the efficacy of PCI-based delivery of bleomycin and the impact on systemic anti-tumor immunity. Mouse colon carcinoma cells (CT26.CL25), stably expressing the bacterial β-galactosidase, were inoculated into the legs of athymic or immuno-competent BALB/c mice strains. The mice were injected with the photosensitizer AlPcS2a and bleomycin (BLM) prior to tumor light exposure from a 670 nm diode laser. Photochemical activation of BLM was found to induce synergistic inhibition of tumor growth as compared to the sum of the individual treatments. However, a curative effect was not observed in the athymic mice exposed to 30 J/cm2 of light while more than 90% of the thymic mice were cured after exposure to only 15 J/cm2 light. Cured thymic mice, re-challenged with CT26.CL25 tumor cells on the contralateral leg, rejected 57-100% of the tumor cells inoculated immediately and up to 2 months after the photochemical treatment. T-cells from the spleen of PCI-treated mice were found to inhibit the growth of CT26.CL25 cells in naïve thymic mice with a 60% rejection rate. The results show that treatment of CT26.CL25 tumors in thymic mice by PCI of BLM induces a systemic anti-tumor immunity.

Paper Details

Date Published: 14 August 2019
Proc. SPIE 11070, 17th International Photodynamic Association World Congress, 110702P (14 August 2019);
Show Author Affiliations
Kristian Berg, Oslo Univ. Hospital (Norway)
Ane Sofie Fremstedal, Oslo Univ. Hospital (Norway)
Anette Weyergang, Oslo Univ. Hospital (Norway)
Jakub Golab, Medical Univ. of Warsaw (Poland)
Ole-Jacob Norum, Oslo Univ. Hospital (Norway)

Published in SPIE Proceedings Vol. 11070:
17th International Photodynamic Association World Congress
Tayyaba Hasan, Editor(s)

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