Effects of high and low single dose irradiation on glioma spheroid invasion into normal rat brain tissue in vitro
Engebraaten, O.; Schwachenwald, R.; Valen, H.; Bjerkvig, R.; Laerum, O.D.; Backlund, E.O.
Anticancer Research 12(5): 1501-1506
1992
ISSN/ISBN: 0250-7005 PMID: 1444212 Document Number: 388991
The effects of radiation on direction on directional migration in monolayer cultures and brain tissue invasion by two glioblastoma celle lines (D-54 MG, D-247 MG) were investigated. The Leksell Gamma Unit was the radiation source and invasion was registered in an in vitro invasion assay developed in our laboratory. As tumor spheroids and brain tissue aggregates were treated simultaneously in cocultures; the effects of radiation on the interaction between the two tissues could be investigated. Tumor spheroids from both cell lines retained their ability to invade and destroy normal brain tissue, even after irradiation with 47.6 Gy. However, while the D-54 MG tumor spheroids showed a dose-dependent reduction of invasion, tumor spheroids from the D-247 MG cell line did not. In addition, radiation produced a dose dependent inhibition of directional migration of cells from D-54 MG spheroids. A similar significant inhibition of directional migration was found in D-247 MG, but it was not dose-dependent. Transmission electron microscopy revealed a loosening of the neuropil in the brain tissue of irradiated cocultures. However, this structural change did not seem to affect the invasiveness of the tumor. In this preliminary study, irradiation could not prevent invasion of two different glioblastoma cell lines into fetal rat brain tissue. Further studies using the same technique may help to understand the influence of ionizing radiation upon the invasion process in gliomas.