Document Detail

Photodynamic Mechanisms induced by a Combination of Hypericin and a Chlorin Based Photosensitizer in Head and Neck Squamous Cell Carcinoma Cells.
MedLine Citation:
PMID:  22882495     Owner:  NLM     Status:  Publisher    
The aim of this study was to elucidate photodynamic therapy (PDT) effects mediated by hypericin and a liposomal meso-tetrahydroxyphenyl chlorin (mTHPC) derivative, with focus on their 1:1 mixture, on head and neck squamous cell carcinoma cell lines. Absorption, excitation and photobleaching were monitored with fluorescence spectrometry, showing the same spectral patterns for the mixture as measured for single photosensitizers. In the mixture mTHPC showed a prolonged photo-stability. Singlet oxygen yield for light-activated mTHPC was Φ(Δ) = 0.66, for hypericin Φ(Δ) = 0.25 and for the mixture Φ(Δ) = ~0.4. A linear increase of singlet oxygen yield for mTHPC and the mixture was found, while hypericin achieved saturation after 35 minutes. Reactive oxygen species fluorescence was only visible after hypericin and mixture-induced PDT. Cell viability was also more affected with these two treatment options under the selected conditions. Examination of death pathways showed that hypericin mediated cell death was apoptotic, with mTHPC necrotic and the 1:1 mixture showed features of both. Changes in gene expression after PDT indicated strong up-regulation of selected heat shock proteins. The application of photosensitizer mixtures with the features of reduced dark toxicity and combined apoptotic and necrotic cell death may be beneficial in clinical PDT. This will be focus of our future investigations. © 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.
Emina Besic Gyenge; Daniel Lüscher; Patrick Forny; Martina Antoniol; Georg Geisberger; Heinrich Walt; Greta Patzke; Caroline Maake
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-8-6
Journal Detail:
Title:  Photochemistry and photobiology     Volume:  -     ISSN:  1751-1097     ISO Abbreviation:  Photochem. Photobiol.     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-8-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376425     Medline TA:  Photochem Photobiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.
Institute of Anatomy, University of Zurich, Winterthurerstr. 190, 8057, Zürich, Switzerland.
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