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Chembiochem. 2016 May 3;17(9):836-42. doi: 10.1002/cbic.201500573. Epub 2016 Mar 7.

Pro-oxidant and Antioxidant Effects in Photodynamic Therapy: Cells Recognise that Not All Exogenous ROS Are Alike.

Author information

1
Chemistry Department, Universidade de Coimbra, Rua Larga, 3004-535, Coimbra, Portugal.
2
Luzitin SA, Ed. Bluepharma, 3045-016, Coimbra, Portugal.
3
Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060, Kraków, Poland.
4
Chemistry Department, Universidade de Coimbra, Rua Larga, 3004-535, Coimbra, Portugal. lgarnaut@ci.uc.pt.

Abstract

Photodynamic therapy (PDT) uses light, photosensitizer molecules and oxygen to generate reactive oxygen species (ROS) that kill cancer cells. Redaporfin, a new photosensitizer in clinical trials, generates both singlet oxygen and superoxide ions. We report the potentiation of redaporfin-PDT in combination with ascorbate and with the inhibition of antioxidant enzymes in A549 (human lung adenocarcinoma) and CT26 (mouse colon adenocarcinoma) cells. The addition of ascorbate and the inhibition of superoxide dismutase (SOD) strongly increased the phototoxicity of redaporfin towards A549 cells but not towards CT26 cells. The inhibition of catalase and the depletion of the glutathione pool also potentiate redaporfin-PDT towards A549 cells. The lower SOD activity of A549 cells might explain this difference. SOD activity levels may be explored to increase the selectivity and efficacy of PDT with photosensitizers that generate radical species.

KEYWORDS:

catalase; hydroxyl radical; photodynamic therapy; radical ions; singlet oxygen; superoxide ion

PMID:
26891856
DOI:
10.1002/cbic.201500573
[Indexed for MEDLINE]

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