Translational research in radiation oncology is important for the detection of adverse
radiation effects, cellular responses, and radiation modifications, and may help to
improve the outcome of radiation therapy in patients with cancer. The present study
aimed to optimize and validate a realtime labelfree assay for the dynamic monitoring
of cellular responses to ionizing radiation. The xCELLigence system is an impedancebased
platform that provides continuous information on alterations in cell size, shape,
adhesion, proliferation, and survival. In the present study, various malignant human
primary fibroblast cells (U251, GBM2, MCF7, A549, HT29) were exposed to 0, 5 and 10
Gy of Cobalt60 radiation. As well as the xCELLigence system, cell survival and proliferation
was evaluated using the following conventional endpoint cellbased methods: Clonogenic,
MTS, and lactate dehydrogenase assays, and apoptosis was detected by fluorescenceactivated
cell sorting. The effects of ionizing radiation were detected for each cell line using
impedance monitoring. The realtime data correlated with the colony forming assay results.
At low cell densities (1,0002,000 cells/well) the impedancebased method was more accurate
at monitoring dosedependent changes in the malignant human primary fibroblast cell
lines, as compared with the endpoint assays. The results of the present study demonstrated
that the xCELLigence system may be a reliable and rapid diagnostic method for the
monitoring of dynamic cell behavior following radiation. In addition, the xCELLigence
system may be used to investigate the cellular mechanisms underlying the radiation
response, as well as the timedependent effects of radiation on cell proliferation
and viability.
