Fig. 7

NBTXR3 nanoparticles released from cancer cells killed by RT can be again endocytosed by live cancer cells. Analysis of recaptures NBTXR3^RED released from 42-MG-BA dead cells. A Schematic representation of the experiment workflow. B Fluorescent microscopy representative images of NBTXR3^RED nanoparticles recapture experiment 48h after co-culture of untreated (CTL, upper panel) or RT-treated (RT, lower panel) conditions. White arrows indicate the presence of NBTXR3^RED nanoparticles in the cytoplasm of 42-MG-BA-ACTB-GFP cells. C Box and whisker plots representation of flow cytometry analysis of NBTXR3^RED MFI in 42-MG-BA-ACTB-GFP cells according to the tested condition (CTL, untreated; RT, radiotherapy-treated), from three independent experiments. Statistical test: Paired t-test. *, p < 0.05. D Representative TEM images of NBTXR3^RED nanoparticles uptake by 42-MG-BA-ACTB-GFP cells 48h after co-culture with dead 42-MG-BA NBTXR3^RED cells. Black arrow: internalized NBTXR3^RED nanoparticles cluster. Scale bar: 0.5µm. Abbreviations: Cyt, cytoplasm; MVB, multivesicular body. E FACS gating strategy employed to isolate NBTXR3^RED-containing 42-MG-BA-ACTB-GFP cells from RT condition for TEM analysis