Fig. 4

TSPO protects GB cells against cytotoxic molecules secreted by activated T cells. a-d Luciferase-based caspase-3/-7 assay to measure caspase-3/-7 activation in TSPO ± (a) U-87 MG, (b) BTIC13, (c) BTIC129 and (d) BTIC13 clones after 4 h of co-culture with T cells (upper panel) or treatment with supernatant of polyclonally activated T cells (lower panel). The graphs show background-subtracted raw data in relative luciferase units (RLU). e, f Real-time cytotoxicity assay to analyze activated supernatant-induced caspase-3/-7 activation over 24 h in (e) BTIC129 and (f) BTIC13 clones. The graphs show the total apoptotic tumor cell area (green object area) per well. Co-culture/treatment with (a, b, d, f) FluTC or supernatant of activated FluTC, (c, e) pre-activated TIL129 or supernatant of activated TIL129. Plain T cell control media (CM) was used to measure the basal level of active caspase-3 /-7. Representative data of at least two independent experiments are shown. Values represent the mean of triplicates ± SD. P-value was calculated using two-tailed Student`s t-test (* = P < 0.05, ** = P < 0.01, *** = P < 0.005, **** = P < 0.001)