Fig. 3

Enrichment of the tumor-initiating cell (TIC) features in TMZ-resistant cells enhanced SOD2. a The estimated stem cell incidence by in vivo extreme limiting dilution assay after subcutaneous injection of parental or resistant cells (left). The tumor size measurement of the serial transplanted tumor cells with 100 cells from the original mouse (P0) to cells from a next passage (P1) is shown in the curve plot (right). b U87MG-r#10 of different passages was extracted, and the qPCR detection of gene expression was shown in the bar graph. c Western blots of SOD2, MGMT, TIC-feature biomarkers were detected in naïve (GBM#4) and resistant (GBM #1) primary tumor. d CD133 was used as the marker for sorting. Western blot was applied for protein expression studies in subsets. e The tumor of different passages was extracted, and the qPCR detection for CD133 and SOD2 mRNA in the serially transplanted GBM#1 tumors was shown in the bar graph. f The qPCR detection of SOD2 in attached or spheroid cultures of U87MG cells. g Western blotting for proteins related to TIC features in sphere and the attached (Con) U87MG cells. (*P < 0.05, ***P < 0.001)