MAPK8 and glioblastoma: As β1 integrin and JNK signaling are critically involved in GBM cell survival [19, 20, 24, 30] and the radiosensitizing potential of their specific targeting unclear, we tested sphere forming capacity and clonogenicity of GBM stem-like cells (GS-8; MGMT positive and TMZ resistant), patient-derived GBM cell cultures (DK32, DK41) (PDC) and GBM cell lines (U343MG, DD-T4) treated either with the β1 integrin-specific inhibitory antibody AIIB2, the JNK inhibitor SP600125 (JNKi) or the AIIB2/JNKi combination (Figure 1, Supplementary Figures 1 and 2).