Novel real-time cell analysis platform for the dynamic monitoring of ionizing radiation effects on human tumor cell lines and primary fibroblasts

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 real-time label-free assay for the dynamic monitoring of cellular responses to ionizing radiation. The xCELLigence system is an impedance-based 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, HT-29) were exposed to 0, 5 and 10 Gy of Cobalt(60) radiation. As well as the xCELLigence system, cell survival and proliferation was evaluated using the following conventional end-point cell-based methods: Clonogenic, MTS, and lactate dehydrogenase assays, and apoptosis was detected by fluorescence-activated cell sorting. The effects of ionizing radiation were detected for each cell line using impedance monitoring. The real-time data correlated with the colony forming assay results. At low cell densities (1,000-2,000 cells/well) the impedance-based method was more accurate at monitoring dose-dependent changes in the malignant human primary fibroblast cell lines, as compared with the end-point 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 time-dependent effects of radiation on cell proliferation and viability.