Photosensitization of MCF-7 cells with diaziquone using visible light: correlation with DNA strand breaks and free radical production.
The ability of visible light to enhance the activity of diaziquone (AZQ) was evaluated in MCF-7 human breast cancer cells. MCF-7 cells were sensitive to AZQ, while visible light illumination had no appreciable effect on cell survival. In the presence of AZQ, visible light potentiated AZQ's cytotoxicity. This potentiation of AZQ activity correlated with a 2-2.5-fold increase in the formation of free radicals (hydroxyl radicals and AZQ semiquinone) and with the production of DNA strand breaks as measured by electron paramagnetic resonance and gel electrophoresis respectively. These results support the hypothesis that free radical formation is part of the mechanism of action of AZQ.
al-Nabulsi
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I
University of Maryland Cancer Center, Division of Developmental Therapeutics, Baltimore 21201.
Gutierrez
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PL
D000970:Antineoplastic Agents / Q000494:pharmacology; D001388:Aziridines / Q000494:pharmacology*; D016227:Benzoquinones / Q000494:pharmacology*; D004249:DNA Damage; D005609:Free Radicals; D006801:Humans; D008027:Light; D010778:Photochemotherapy; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects* / Q000528:radiation effects
D000970:Antineoplastic Agents; D001388:Aziridines; D016227:Benzoquinones; D005609:Free Radicals; D011838:Radiation-Sensitizing Agents; C029108:diaziquone