Fig. 1.

IGF-1R is preferentially expressed in TMZ-resistant glioma cells. a Cell surface biotinylated proteins, derived from lysed TMZ-sensitive (U251) and TMZ-resistant (UTMZ) glioma cells, were resolved on SDS/PAGE gels, and transferred to PVDF membranes. Proteins were detected by Western blot with HRP-streptavidin (left), and anti-IGF-1R antibody (right). b Visualization of the cell surface of non-fixed, live TMZ-sensitive U251 and TMZ-resistant UTMZ glioma cells with immunofluorescence using fluorescein-conjugated antibodies against IGF-1R (bottom panel) and isotype control (top panel). Magnification 400×. c Expression of IGF-1R in GBM and low-grade gliomas compared with non-tumor tissue. Median values are represented as lines in the scatter plot. *P < 0.05, ****P < 0.0001, ANOVA. d Expression of IGF-1R in GBM correlated with patient survival in the TCGA database (optimal cutoff 9.73): TCGA GBM dataset (left) and TCGA GBMLLG dataset (right). Numbers between brackets indicate median survival