Article
Experimental 5-ALA Photodynamic Therapy of a Human Chordoma Cell Line
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Published: | June 9, 2017 |
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Objective: Chordomas are rare malignant tumors with infiltrating growth. Surgery and radiotherapy are the mainstay of therapy. However recurrences are very common. As chemotherapy is ineffective, other adjuvant modalities have to be explored. Recently, 5-aminolevulinic acid based photodynamic therapy (5-ALA PDT) has come into focus of anticancer treatment. The present study investigated the efficacy of 5-ALA PDT in vitro on a human cell line.
Methods: Experiments were performed on a human chordoma cell line (UCH-2). Preliminary FACS-analysis with different 5-ALA concentrations had been performed after 4h and 6h incubation time. In the main experiment, cultured cells were incubated for 6h with different 5-ALA concentrations (15; 30; 40; 50 microgr/ml) and subsequently irradiated by laser light (635nm, 625 sec, 18.75 J/ cm2). Cell viability was tested 24h after PDT by WST-1 assay. Negative control groups (5-ALA only and laser only) were realized.
Results: Preliminary FACS-analysis had suggested a higher accumulation of protoporphyrin IX (PpIX) after 6h in contrast to 4h incubation time. The UCH-2 cell line could be effectively destroyed by 5-ALA PDT. 5-ALA concentrations of 15; 30; 40; 50 microgr/ml showed a dose-dependent effect with cell survival rates of 86.9%; 54.2%; 22.4% and 12.8%, respectively. 5-ALA or laser irradiation alone did not result in significant cell death.
Conclusion: 5-ALA PDT effectively caused cell death in a human chordoma cell line in vitro. There was a dose-dependent effect. Preliminary FACS-analysis had shown a superior effect of 5-ALA PDT after 6h of incubation time. Further experiments to optimize treatment parameters and on different cell lines and tumor tissue are needed to confirm these experimental results.