Artikel
Distribution of ezrin in interferon-gamma-induced apoptosis of primary glioblastoma cultures
Verteilung von Ezrin bei Interferon-g-induzierter Apoptosis von primären Gliomzellkulturen
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Autoren
Veröffentlicht: | 4. Mai 2005 |
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Gliederung
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Objective
The actin-binding protein ezrin is related to malignancy and invasivity of glial tumors. Furthermore a link was described between ezrin expression and the induction of apoptosis in tumor cells. With the aim of finding a parameter to predict the response of glioblastoma cells to irradiation or chemotherapy, we used a paradigm of IFN-γ induced tumor cell apoptosis to study effects on the distribution of ezrin, comparing 16 primary glioblastoma cultures to the glioblastoma cell line U373MG.
Methods
Primary cell cultures were grown in tissue culture flasks and on multi chamber slides to 2/ confluency and then treated with IFN-γ (100ng/ml) versus controls with serum free medium only in at least 3 parallel essays. We established proliferation (MIB-1) and expression of ezrin (ab3C12) by immunofluorescence, and apoptosis with the TUNEL method. Ezrin distribution was quantified using laser scanning microscopic line scans in defined distances to the nucleus.
Results
All primary cell cultures showed increased induction of apoptosis following application of IFN-γ, whereas no effect was observed in the cell line. Proliferation was only marginally influenced. Ezrin-expression decreased and was altered in apoptotic cells but not in surviving cells of IFN-γ - treated cultures, which however showed increased distribution of ezrin to the nucleus.
Conclusions
These results link the distribution of ezrin to the induction of apoptosis by IFN-γ. Ezrin is redistributed and finally lost during apoptosis. Ezrin nuclear seggregation in surviving tumor cells may represent the morphological correlate of a therapy escape mechanism in glioblastoma cells.