EPICeA : A comprehensive radiobiological assay using dynamic single cells phenotypic tracking under videomicroscopy

Abstract

Abstract Cellular assays modeling tumor radiosensitization or normal tissue radiotoxicity commonly support knowledge in radiobiology. Despite worldwide use, outcomes from those assays remain limited since analyses commonly estimate radiosensitivity for the whole-cell population at a specific time point post-radiation disregarding dynamic mechanistic evaluation at single-cell granularity. This manuscript presents EPICeA, a novel integrated radiobiological tool using videomicroscopy to investigate the dynamic radiobiological response of irradiated tumor cells at both single-cell and whole population levels. Manual tracking of U251 glioblastoma cells was directly performed from movies for five consecutive days after exposure up to 15Gy. Observables (cell number, division, abnormal mitosis, and death) were directly extracted from videos and incorporated into dedicated in-house computational algorithms to evaluate radiobiological cell response. First, cladograms illustrating radiation-induced behaviors of each irradiated mother cell and their related out-springs were set up. Then, the population means and single-cell distributions for different radiobiological parameters were computed and analyzed as a function of time and dose. Finally, Pearson correlation coefficients for those 55 features derived from those observables and relevant in radiobiology were established, showing singular correlations. By proposing EPICeA, we strength the characterization of radiobiological response allowing a more accurate evaluation of cell radiosensitivity during dose escalation.