"Anthracene studies in photodynamic therapy and other ongoing projects"

Anthracene studies in photodynamic therapy and other ongoing projects. Odrun A. Gederaas1, Monica Siksjø2, Bastien Mettra3, Cyrille Monnereau3, Kjartan W. Egeberg1, Chantal Andraud3 and Mikael Lindgren2 1) Department of Cancer Research and Molecular Medicine, University of Science and Technology, N-7489 Trondheim, Norway 2) Department of Physics, N-7491 Trondheim, Norway 3) CNRS UMR 5182, Université Lyon 1, Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France Hydrophilic and hydrophobic chromophores are taken up by cells and are usually located in cellular lipid membranes but accumulate in different compartments of the cell. The aim of this study was to investigate biophysical properties of four light sensitive chromophores1,2 for bioimaging applications, and to test their efficiency as potential photosensitizer in photodynamic therapy (PDT). This is a general statement and not verified stringently for all of the probes. The chromophores where all proven to accumulate within tested F98 glioma and CHO-K1 hamster ovary cells. For one of the chromophores (Ant-Poly Imidazole), the polycationic nature of the side chain helped its permeation inside the cell nucleus. Then, characterizations of light induced cell death and DNA damage (Comet assay) were performed using cell survival assay (MTT) and confocal microscopy. Our studies demonstrate structural and morphological changes within the two cell lines upon light/no light treatment after sensitizer or chromophore incubation. Quite surprisingly, one of the hydrophilic anthracene compounds (Ant-Poly Imidazole) although not specifically designed to that end, showed promising results for PDT with accelerated cell death upon illumination compared to the other hydrophilic anthracene compound (Ant-PHEA). Transient absorption measurements revealed a long lived triplet state in one of the tested bromobenzene derivative (DBB2-OAc). The latter also showed generation of singlet oxygen from transient luminescence measurement in the singlet oxygen phosphorescence band, making it a promising candidate for type II PDT. This project is an ongoing collaborating study between ENS Lyon, France, and NTNU, Norway. 1. Monnereau C. et al., New. J. Chem., 2012, 36, 2328-2333. 2. Gallavardin T. et al., Chem. Commun., 2012, 48,1689-169.