Metabolic effects of photodynamically induced apoptosis in an erythroleukemic cell line. A 31P NMR spectroscopic study of Victoria-Blue-BO-sensitized TF-1 cells
✍ Scribed by Angèle Viola; Norbert W. Lutz; Christine Maroc; Christian Chabannon; Michel Julliard; Patrick J. Cozzone
- Publisher
- John Wiley and Sons
- Year
- 2000
- Tongue
- French
- Weight
- 152 KB
- Volume
- 85
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Victoria Blue BO (VB BO) is a new and promising photosensitizer currently being evaluated for photodynamic therapy (PDT). Its photochemical processes are mediated by oxygen radicals, but do not involve singlet oxygen. We used (31)P NMR spectroscopy of VB-BO sensitized TF-1 leukemic cells to gain further insight into the biochemical mechanisms underlying PDT-induced cell death. Sham-treatment experiments were performed to evaluate the effects of this photosensitizer in the absence of light irradiation. Significant metabolic differences were detected for TF-1 cells incubated with VB BO but not exposed to light, as compared with native cells (controls). These changes include reductions in phosphocreatine, UDP-hexose and phosphodiester levels (as percentage of total phosphate) and slightly reduced intracellular pH. Complete phosphocreatine depletion, significant acidification and concomitant inorganic-phosphate accumulation were observed for TF-1 cells irradiated after incubation with VB BO. Moreover, significant changes in phospholipid metabolites, i.e., accumulation of cytidine 5'-diphosphate choline and a decrease in phosphodiester levels, were observed for PDT-treated vs. sham-treated cells. Perturbations of phospholipid metabolism may be involved in programmed cell death, and the detection of a characteristic DNA ladder pattern by gel electrophoresis confirmed the existence of apoptosis in PDT-treated TF-1 cells.