A hypothesis for the molecular mechanism of tumor killing by porphyrins and light.
Tumor cells have an absence or deficiency of mitochondrial superoxide dismutase. Superoxide is produced when hematoporphyrin derivative is exposed to visible light. A significant portion of the antitumor effect of porphyrin:light therapy is hypothesized to be mediated by superoxide.
D006415:Hematoporphyrins / Q000528:radiation effects*; D006801:Humans; D008027:Light; D008954:Models, Biological; D009369:Neoplasms / Q000378:metabolism / Q000532:radiotherapy*; D009580:Nitroblue Tetrazolium; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
D006415:Hematoporphyrins; D013481:Superoxides; D009580:Nitroblue Tetrazolium; D013482:Superoxide Dismutase; D010100:Oxygen