Fig. 2: IGF-1R inhibition suppresses HGG cell survival and enhances radiosensitivity of pHGG cells.

a Characterisation of RTK signalling in HGG cells. Western blots of whole cell extracts prepared from sub-confluent cultures in full medium with 10% FCS. Similar results were seen in 2–3 independently-prepared sets of cell extracts. b Serum-starved cells were treated with BMS-754807 or solvent control (0.015% DMSO) for 75 min and in the final 15 min with 50 nM IGF-1. Similar results were obtained in an independently-prepared set of cell extracts. c Effect of BMS-754807 on cell survival, expressed as mean ± SEM % survival of solvent-treated controls, pooled data from 2–3 independent experiments (6–9 data points) for aHGG and three independent experiments for pHGG cell lines. Legends show SF₅₀ values, interpolated from the data as concentrations that suppressed cell survival to 50% of survival in solvent-treated controls. d Cells were pre-treated with solvent or 300 nM BMS-754807 (concentration selected from Fig. 2b-c as blocking IGF-1R while allowing sufficient survival to assess IR response) and 4 h later were irradiated. Graphs show pooled data from three independent assays in each cell line, mean ± SEM survival expressed as % survival in unirradiated dishes, with DER values. e SF188 cells cultured in full medium with 10% FCS were treated with solvent (control treatment) or 300 nM BMS-754807 for 4 h and irradiated (6 Gy). After 3 or 5 days, cells were lysed for western blot. Results are representative of three independent experiments. f SF188 cells were cultured, treated with solvent or BMS-754807 and irradiated as in e, and after 24 h collected for analysis by flow cytometry, showing mean ± SEM of five independent analyses (*p < 0.05, **p < 0.01, ***p < 0.001 by one-way ANOVA). g, h. SF188 cells were cultured, treated and irradiated as e, and fixed and stained at intervals for foci formed by: g, γH2AX; h, 53BP1. Left, representative images; right, graphs showing mean ± SEM foci per cell (n = 60–70 cells per condition from three independent experiments; *p < 0.05, **p < 0.01, ***p < 0.001).