Article
The green tea catechin EGCG induces cell death in human glioblastoma cell cultures
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Authors
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Susanne Grube
- Klinik für Neurochirurgie, Universitätsklinikum Jena, Friedrich Schiller Universität Jena
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Christine Kögler
- Klinik für Neurochirurgie, Universitätsklinikum Jena, Friedrich Schiller Universität Jena
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Diana Freitag
- Klinik für Neurochirurgie, Universitätsklinikum Jena, Friedrich Schiller Universität Jena
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Rolf Kalff
- Klinik für Neurochirurgie, Universitätsklinikum Jena, Friedrich Schiller Universität Jena
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Christian Ewald
- Klinik für Neurochirurgie, Universitätsklinikum Jena, Friedrich Schiller Universität Jena
| Published: | June 2, 2015 |
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Outline
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Objective: Cancer-preventive and anti-proliferative effects of the green tea catechin epigallocatechin gallate (EGCG) on tumorigenesis and tumor progression have been reported for different types of tumors. These effects are achieved by induction of apoptosis, cell cycle regulation and inhibition of cell proliferation.
Method: Primary glioblastoma cell cultures were established and maintained in our laboratory. To determine the half maximal inhibitory concentration of EGCG, cell cultures LT68 and MW21 were treated with increasing concentrations of the pure substance and a commercially available green tea extract. Viability assays were performed with concentrations of 100nM (physiological concentration) and 500μM (determined IC50) of both EGCG and extract respectively. Induction of apoptosis by EGCG was analysed by confocal microscopy after Hoechst33258 staining.
Results: The half maximal inhibitory concentration determined for the pure substance and the commercially available green tea extract were around 500μM (432μM to 565μM). 500μM EGCG significantly reduced viability in LT68 by 70.2% and in MW21 by 66.5% compared to untreated controls (p<0.001) after 24 hours. For the green tea extract (500μM) viability was reduced by 85.9% (LT68) and 80.2% (MW21) respectively. On the other hand, the tests with the physiological concentration of 100nM revealed a slight increase of the cell viability.
Microscopic screening for signs of apoptosis showed that after 24 hours the physiological concentration of EGCG did not alter the nuclear morphology. Another 24 hours later, several cells displayed early apoptotic morphology, such as peripheral aggregation of nuclear chromatin. Incubated with the IC50 concentration for 24 hours, nearly all cells were found to be in the late stage of apoptosis with advanced chromatin condensation, nuclear condensation and formation of apoptotic bodies.
Conclusions: We could show a concentration and time dependent decrease in the viability of primary glioblastoma cell cultures under influence of the green tea catechin EGCG as pure substance as well as commercially available green tea extract. EGCG in concentrations above the physiological level induce apoptosis in primary glioblastoma cells.
