Figure 5. Growth inhibition and genotoxic effects of hydrogen peroxide exogenously added to culture media in MCTS.

(a) The time-evolution of the growth of HCT116 spheroids after their transfer into culture medium in the presence of increasing concentration of exogenous hydrogen peroxide. Spheroids were cultured five days in DMEM and then transferred in culture medium containing H₂O₂ at day 0. Data are shown as means ± SD from four independent experiments (b) DNA damage due to hydrogen peroxide concentration added in culture media without any plasma treatment. Genotoxicity is analyzed by immunodetection of the phosphorylation of the histone variant H2AX (phospho- H2AX, green) on 5 μm cryosections of control HCT116 MCTS or MCTS for transfer time Ttrans 1 h. DAPI (blue) correspond to the Nuclei. Data shown are representative images from four independent experiments. Scale bar, 100 μm.