Photochemical reactions after nano particle stimulating. In vitro and in vivo studies

Photochemical reactions after nano particle stimulating. In vitro and in vivo studies Odrun A. Gederaasa, Monica Siksjøb, Kristin G. Sæterbøb, Thor Bernt Meløb, Astrid Bjørkøyb, Mikael Lindgrenb,c, Vanya Bogoevad a) Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, N-7491 Trondheim, Norway b) Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway c) Department of Physics, Chemistry and Biology, Linköping University, SE-58183 Linköping, Sweden d) Department Molecular Biology of Cell Cycle Institute of Molecular Biology, Bulgarian Academy of Sciences, Acad. “G. Bonchev” Str., Bl. 21, Sofia 1113, Bulgaria Abstract Photodynamic therapy (PDT) is a noninvasive treatment for solid malignant and flat tumors. Both endogen and exogen added photosensitizers1 were used in vitro and in vivo studies according to development of new treatment strategies. The light activated sensitizers catalyze photochemical reactions that produce reactive oxygen species which can cause cancer cell death. The photophysical properties of the photosensitizer ruthenium (II) porphyrin (RuP) have been investigated, along with its PDT efficiency onto rat bladder cancer cells (AY27)2. Optical spectroscopy verified that RuP is capable to activate singlet oxygen via blue and red absorption bands and inter system crossing (ISC) to the triplet state3. In vitro experiments on AY27 indicated increased photo-toxicity of RuP (20 µM, 18 h incubation) after cell illumination (at 435 nm, 13 mW/cm2), as a function of blue light exposure. Cell survival fraction was significantly reduced to 14% after illumination (20 min), RuP (20 µM), whereas the “dark toxicity” of RuP (20 µM) was 83%. Structural and morphological changes of cells were observed, due to RuP accumulation, as well as light-dependent cell death, was registered by confocal microscopy. Flow cytometry verified that PDT-RuP (50 µM) triggered significant photo-induced cellular destruction with photoxicity of (93% ±0.9%). Interestingly, the present investigation of RuP-PDT showed that the dominating mode of cell death is necrosis. RuP “dark toxicity” compared to the conventional chemotherapy drug cisplatin, showed higher toxicity, both evaluated by MTT assay (24 h). In conclusion, the present investigation shows that RuP induces cell damage of bladder cancer cells. 1. Gederaas O. A. et al., Photochem. Photobiol. Sci. 2015; 14(7); 1357-6 2. Bogoeva V. et al., J Photochem Photobiol B. 2015(20); 153:276-280 3. Glimsdal E. et al., J Phys. Chem A. 2009(113); 3311-3320