Document Detail

Optimizing photodynamic therapy by liposomal formulation of the photosensitizer pyropheophorbide-a methyl ester: in vitro and ex vivo comparative biophysical investigations in a colon carcinoma cell line.
MedLine Citation:
PMID:  20714673     Owner:  NLM     Status:  MEDLINE    
Photodynamic therapy (PDT), induced by a photosensitizer (PS) encapsulated in a nanostructure, has emerged as an appropriate treatment to cure a multitude of oncological and non-oncological diseases. Pyropheophorbide-a methyl ester (PPME) is a second-generation PS tested in PDT, and is a potential candidate for future clinical applications. The present study, carried out in a human colon carcinoma cell line (HCT-116), evaluates the improvement resulting from a liposomal formulation of PPME versus free-PPME. Absorption and fluorescence spectroscopies, fluorescence lifetime measurements, subcellular imaging and co-localization analysis have been performed in order to analyze the properties of PPME for each delivery mode. The benefit of drug encapsulation in DMPC-liposomes is clear from our experiments, with a 5-fold higher intracellular drug delivery than that observed with free-PPME at similar concentrations. The reactive oxygen species (ROSs) produced after PPME-mediated photosensitization have been identified and quantified by using electron spin resonance spectroscopy. Our results demonstrate that PPME-PDT-mediated ROSs are composed of singlet oxygen and a hydroxyl radical. The small amounts of PPME inside mitochondria, as revealed by fluorescence co-localization analysis, could maybe explain the very low apoptotic cell death measured in HCT-116 cells.
Pierre-Henri Guelluy; Marie-Pierre Fontaine-Aupart; Angeliki Grammenos; Sandrine Lécart; Jacques Piette; Maryse Hoebeke
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Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2010-08-12
Journal Detail:
Title:  Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology     Volume:  9     ISSN:  1474-9092     ISO Abbreviation:  Photochem. Photobiol. Sci.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-08-25     Completed Date:  2010-12-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101124451     Medline TA:  Photochem Photobiol Sci     Country:  England    
Other Details:
Languages:  eng     Pagination:  1252-60     Citation Subset:  IM    
Laboratory of Biomedical Spectroscopy, Institute of Physics, B5a, University of Liège, Sart-Tilman, B-4000, Liège, Belgium.
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MeSH Terms
Carcinoma / drug therapy
Cell Line, Tumor
Colonic Neoplasms / drug therapy
Dimyristoylphosphatidylcholine / chemistry
Electron Spin Resonance Spectroscopy
Liposomes / chemistry
Microscopy, Confocal
Mitochondria / drug effects
Photosensitizing Agents / administration & dosage*,  chemistry,  therapeutic use
Porphyrins / administration & dosage*,  chemistry,  therapeutic use
Reactive Oxygen Species / metabolism
Spectrometry, Fluorescence
Reg. No./Substance:
0/Liposomes; 0/Photosensitizing Agents; 0/Porphyrins; 0/Reactive Oxygen Species; 0/pyropheophorbide-a methylester; 13699-48-4/Dimyristoylphosphatidylcholine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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