Artikel
Time lapse video microscopy to study the properties of human glioblastoma stem cells
Untersuchung der Eigenschaften von humanen Glioblastom-Stammzellen mit einem Mikroskop-gestützten Vitalbeobachtungssystem
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Veröffentlicht: | 30. Mai 2008 |
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Gliederung
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Objective: Glioblastoma stem cells are usually cultured as free floating spheres. Experiments with neural stem cells demonstrated that neurospheres are highly motile structures proned to fuse even under ostensibly "clonal" culture conditions. So far, no data exist that cultured glioblastoma stem cells show a similar behaviour.
Methods: Human glioblastoma specimen were mechanically dissociated and glioblastoma stem cells were expanded as spheres using serum-free medium in the presence of EGF and bFGF. Using a life cell imaging system we have studied migration properties of these spheres. Immunofluorescence analysis using antibodies against stem cell markers was used to verify the stem cell characteristics. To study the differentiation capacity, glioblastoma spheres were plated without growth factors on coated glass coverslips and outgrowing cells were analysed using antibodies specific for astrocytes and neurons.
Results: The majority of cells in the cultured spheres showed stem cell characteristics. Glioblastoma stem cells could be differentiated towards astrocytes and neurons, as was demonstrated by loss of nestin expression and the aquisition of GFAP or beta-III-tubulin immunoreactivity in subpopulations of cells. Using a time lapse video microscopy system we surprisingly found that larger spheres could be generated by fusion of smaller spheres and not only by cell division. These results are in contrast to the so far supposed clonogenic nature of glioplastoma spheres. Further we observed a continuous uptake and shedding of single cells, which as well as the fusion events will be shown by several video sequences.
Conclusions: Our results show, that the generation and growth of our cultured glioblastoma spheres is stimulated by fusion events rather than mitosis and that a clonogenic nature of glioblastoma spheres is rather unlikely. The method of life video microscopy seems to be an ideal tool to investigate cell vitality and migratory properties of glioblastoma stem cells.