Fig. 1

B7-H3 is increased in SVZ-GBM cells and in GBM tissue, with specific 4IgB7-H3 isoform expression. a Schematic representation of the xenograft mouse model. Four weeks post-graft, U87MG cells were isolated from the initial tumor mass (TM-GBM cells) or from the subventricular zone (SVZ-GBM cells) and established in culture. b Western blot (WB) analysis of B7-H3 in proteins extracted from TM- and SVZ-GBM cells (N = 3). c Quantitative RT-PCR analysis of B7-H3 normalized to GAPDH in cells described in B. (N = 3). d Immunofluorescent staining of B7-H3 (red) and nuclei (DAPI, blue) in non-cancerous (NC) brain (N = 5) vs GBM (N = 6) tissues. Scale bar = 50 µm and scale bar for enlarged images = 10 µm. e Immunofluorescent quantification showing the percentage of B7-H3 positive cells relative to the total number of cells (DAPI positive) in tissues described in (d). f CD276 mRNA expression analysis from REpository for Molecular BRAin Neoplasia DaTa (REMBRANDT), The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) databases in GBM (N = 219 REMBRANDT, N = 152 TCGA and N = 388 CGGA) compared to non-tumoral brain tissues (N = 28 REMBRANDT) and lower-grade gliomas; oligodendroglioma (N = 67 REMBRANDT, N = 191 TCGA and N = 112 CGGA), oligoastrocytoma (N = 130 TCGA and N = 9 CGGA), astrocytoma (N = 147 REMBRANDT, N = 134 TCGA and N = 175 CGGA), anaplastic oligodendroglioma (N = 94 CGGA), anaplastic oligoastrocytoma (N = 21 CGGA) and anaplastic astrocytoma (N = 214 CGGA). Data are given as mean ± SD *** < 0.001 (ANOVA1). g Representative image of a WB analysis of B7-H3 (4IgB7-H3; 2IgB7-H3). Four samples in each group are shown out of N = 8 for NC brain and N = 14 for GBM. U87MG cells were used as control. h–j WB quantification of total B7-H3 (4IgB7-H3 + 2IgB7-H3), 4IgB7-H3 or 2IgB7-H3, respectively. Quantification was based on N = 8 for NC brain and N = 14 for GBM. Actin was used as internal control for WB analysis. Normalized quantification is relative to NC brain tissue and expressed as a percentage. Graphs are mean ± SD with NS = not significant, **p < 0.01 and *** < 0.001 (t-test)