Electron paramagnetic resonance evidence of the generation of superoxide (O2.-) and hydroxyl (.OH) radicals by irradiation of a new photodynamic therapy photosensitizer, Victoria Blue BO.
Electron paramagnetic resonance (EPR) experiments were performed on Victoria Blue BO, a cationic dye whose photocytotoxicity has been studied against the human leukaemic cell lines K-562 and TF-1. EPR experiments with 2,2,6,6-tetramethyl-4-piperidone and spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide showed that, on illumination in aerated aqueous solution or DL-alpha-dipalmitoylphosphatidylcholine liposomes, photoexcited Victoria Blue BO is unable to generate 1O2, whereas O2.- and .OH are trapped by 5,5-dimethyl-1-pyrroline-N-oxide in the presence or absence of electron donors. The O2.- formed probably leads to the .OH radical, with an efficiency which is increased by electron donors such as FE2+.
Viola
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Laboratoire AM, URA CNRS 1411, Faculté des Sciences Saint-Jérôme, Marseille, France.
Hadjur
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Jeunet
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Julliard
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M
D015060:1,2-Dipalmitoylphosphatidylcholine; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004337:Drug Carriers; D004578:Electron Spin Resonance Spectroscopy; D006801:Humans; D017665:Hydroxyl Radical; D007700:Kinetics; D007938:Leukemia; D004915:Leukemia, Erythroblastic, Acute; D008027:Light; D008081:Liposomes; D008433:Mathematics; D017319:Photosensitizing Agents / Q000737:chemistry / Q000528:radiation effects* / Q000633:toxicity; D000644:Quaternary Ammonium Compounds / Q000737:chemistry / Q000528:radiation effects* / Q000633:toxicity; D013113:Spin Labels; D013481:Superoxides; D013816:Thermodynamics; D014407:Tumor Cells, Cultured
D004337:Drug Carriers; D008081:Liposomes; D017319:Photosensitizing Agents; D000644:Quaternary Ammonium Compounds; D013113:Spin Labels; D013481:Superoxides; C084160:Victoria blue BO; D015060:1,2-Dipalmitoylphosphatidylcholine; D017665:Hydroxyl Radical