Fig. 5: NPI-0052 plus γ-radiation induces a synergistic apoptotic effect in G3/G4-MB cells.

a DAOY and ICb-1299 cells were treated with 0, 2 and 4Gy γ-radiation. After 24 h cell viability was measured with CellTiter-Glo (n = 4) ± SEM; **P < 0.001; ***P < 0.0001. b Dose–response curves fitted to experimental data for cell viability in DAOY and ICb-1299 treated with different concentrations of NPI-0052 alone or in combination with γ-radiation. Pre-treatment condition: MB cells were treated with different concentrations of NPI-0052 for 4 h, followed by treatment of 2 or 4Gy γ-radiation for 24 h. For the post-treatment condition: MB cells were treated with 2 or 4 Gy radiation doses, and 4 h later with different concentrations of NPI-0052 for 24 h. Cell viability was then measured with CellTiter-Glo (n = 3) ± SEM; *P < 0.01; ***P < 0.0001. c ICb-1299 cells were treated or not with 4 Gy γ-radiation for 4 h, followed by 0, 0.002 or 0.01 ng/μL NPI-0052. After 24 h cells were collected and a western blot of lysed cells was performed and probed with primary anti-p73 (1/1000), anti-p53 (1/1000), cleaved caspase-8 (1/1000), caspase-9 (1/1000) and GAPDH (1/5000) antibodies