Fig. 2

Higher abundance of calpains in initial and recurrent glioblastoma. a Fc values for proteomic quantification of CAPN1, CAPN2, and CAPNS1 in five representative samples used for initial proteomic analysis shown in Fig. 1. b–d Expression of calpain-1 (CAPN1, b), calpain-2 (CAPN2, c), and calpain small subunit 1 (CAPNS1, d) in normal brain (NB) tissue and glioblastoma patient samples (GBM). Data were obtained from TCGA and GTEX data (www.gepia2.cancer-pku.cn) on n = 207 (NB, blue bars) and n = 163 (GBM, red bars) individuals. For CAPN2, expression difference is significant with p < 0.01. e Western Blot analysis of CAPN1 and CAPN2 from representative tissue samples of normal brain (access tissue, n = 3) and tumor tissue (GBM, n = 4). Molecular weights of CAPN1 and -2 are indicated by arrows on the right. As loading control, ß-actin was used. f Immunohistochemistry for CAPN1 and CAPN2 in normal brain (NB, left) and sections from GBM (right) tissue. Neuronal staining is denoted by arrowheads in the left panel, and asterisks mark small blood vessels. In tumors, arrowheads denote tumor cells and asterisks large blood vessels with positive staining for CAPN1 and CAPN2 in endothelia. Scale bars in all images, 50 µm. g–i Expression of CAPN1 and CAPN2 in patient-matched initial GBM (iGBM) and recurrent GBM (rGBM) samples in 19 patients. g CAPN1 expression is low and induced in 11 out of 19 patients. h CAPN2 high expression in 5 out of 19 patients shows induction of CAPN2 in 4 out of 5 patient samples. i CAPN2 low expression is induced in 11 out of 14 patient samples. In total, 4 patients showed a downregulation of CAPN2 in recurrent GBM, whereas 15 out of 19 show an increase in CAPN2 in recurrent tumors. j Overall survival time of 131 patients with either high (red) or low (blue) calpain expression. Data were obtained from www.gepia2.cancer-pku.cn (accessed on 28^th September, 2022)