E. Borisova(1), Ya. Andreeva(1), K. Ivanova-Todorova(2), E. Naydenov(3), D. Kyurkchiev(2), K. Minkin(3)
1)Institute of Electronics, BAS, 72, Tzarigradsko chaussee blv., Sofia
2)Laboratory of Clinical immunology, University Hospital " St. Ivan Rilski",
15 "Akademik Ivan Evstratiev Geshov " blvd., MU Sofia
3)University Hospital “St. Ivan Rilski”, 15 "Akademik Ivan Evstratiev Geshov " blvd., MU Sofia
Photodynamic therapy is well-established and extensively used method in treatment of different cancer types. This research reveals its potential in the treatment of cultivated human glioblastoma cells with adherent morphology. As the blood-brain barrier (BBB) permeability of the drugs is a significant problem that could not be solved for large biomolecules, we search for an appropriate low-molecular weight photosensitizer that could be applied for photodynamic treatment of glioblastoma cells. Such promising compound could be a delta-aminolevulinic acid (5-ALA), which could pass BBB and plays the role of precursor of a protoporphyrin IX ( PpIX) – photosensitizer that is accumulated selectively in the tumour cells and could be a proper tool in PDT of human glioblastoma. [1, 2] This study investigates effect of using different fluence rates and light doses, and aims to establish the most efficient values for further clinical application.
For the needs of PDT application a illumination device was developed in Laboratory of Biophotonics, BAS based on light-emitting diode (LED) matrix light sources for therapeutic application emitting at 635 nm. The device is optimized for PDT in combination with aminolevulinic acid/protoporphyrin IX applied as a photosensitizer drug. By the means of FACSCalibur flow cytometer (Becton Dickinson, USA) and Cell Quest Software was made evaluation of PDT effect on used human glioblastoma cells.
Treatment of glioblastoma tumours continues to be a very serious issue and there is growing need in development of new concepts, methods and cancer-fighting strategies. PDT may contribute in accomplishing better results in cancer treatment and can be applied as well in combination with other techniques.
Acknowledgments: This work is supported in part by the NSF-BMES under grants #MU-03-46/2011 and #DFNI-B02/9/2014.
 S. Madsen, C. Sun, B. Tromberg, H. Hirschberg, “Repetitive 5-aminolevulinic acid-mediated photodynamic therapy on human glioma spheroids”, Journal of Neuro-Oncology, 62, 243–250, (2003)
 H. Inoue, Y. Kajimoto, “Massive apoptotic cell death of human glioma cells via a mitochondrial pathway following 5-aminolevulinic
acid-mediated photodynamic therapy”, J Neurooncol, 83, 223–231, (2007)
Dr. Ekaterina Georgieva Borisova
Institute of Electronics, Bulgarian Academy of Sciences, Associate Professor
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