Artikel
Modulation of Carboplatin chemotherapy and cytotoxicity of the nitric oxide donor Spermine-NO in glioma cells in vitro
Modulation einer Carboplatin-Chemotherapie und zytotoxische Wirkung des Stickstoffmonoxiddonors Spermine-NO in Gliomzellen in-vitro
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
Nitric oxide(NO) and related substances have multiple cytotoxic, chemo- and radiosensitizing effects and are implicated in the regulation of vascular permeability and blood flow. Furthermore, we recently published that concomitant i.v. administration of the NO donor Proli/NO and Carboplatin lead to long-term survival in rats harbouring intracranial C6 gliomas. The objective of this study was to investigate the cytotoxicity of the NO donor Spermine-NO and its potential synergistic effect with Carboplatin in C6, U87 and in human glioblastoma (GBM) cells in vitro.
Methods
Rat C6, human U87 and GBM cells derived from a patient glioblastoma were cultured in a standardized manner and then incubated with Spermine-NO at doses in the range from 10-12 M to 10-2 M for 24, 36 or 48h. Cytotoxicity of Carboplatin was evaluated at concentrations between 500 µM and 2 mM. Furthermore, the cells were simultaneously exposed to Spermine-NO and Carboplatin or each substance alone. Cell viability (%) was calculated after trypan blue dye exclusion assay and cell viability were analysed statistically using ANOVA test and Student´s Newman Keul test.
Results
Exposure of C6, U87 and GBM cells to Spermine-NO at concentrations ≥10-4 M was directly cytotoxic. In C6 cells, addition of Spermine-NO (10-4 M) to the Carboplatin (500 µM) incubation over 36h significantly enhanced cytotoxicity of the drug (52±13% of viable cells (Carboplatin) vs. 65±37% (Spermine-NO) vs. 26±5% (Spermine-NO+Carboplatin); p=0.0006). Similar results were obtained in GBM cells combining 500 µM Carboplatin and 5x10-4 M Spermine-NO after a 48h incubation (p=0.0038). While Spermine-NO and Carboplatin were both significantly cytotoxic in U87 cells, no synergistic effects between these two substances could be observed in this cell line.
Conclusions
Therefore we conclude that Spermine-NO is intrinsically cytotoxic in all three cell lines and has a potent chemosensitizing effect in combination with Carboplatin in C6 and GBM cells. Using these synergistic effects of NO and Carboplatin might be a new strategy to improve the efficacy of chemotherapy for gliomas.