Fig. 1. Patient-derived glioblastoma sphere cells are enriched in the stem cell signature.

a, b Serum-induced differentiation of patient-derived glioblastoma sphere cells. Bright field image of cells taken using a Cytation 3 microplate reader (Bioteck) after the addition of (a) various concentrations of serum for 7 days and (b) 10% serum for the indicated number of days; a representative image of at least three independent experiments is shown. c The expression level of total RNA from TS13-20 spheres (D0) and their differentiated counterparts (D7) that were treated with 10% serum for 7 days was determined by RNA sequencing. Gene set enrichment analysis (GSEA) showed that sphere cells were enriched in neural stem cell and embryonic stem cell gene signatures. (NES: normalized enrichment score, FDR: false discovery rate). Gene sets are listed in Supplementary Table S1. d RNA sequencing results were validated by analyzing the expression of genes using reverse-transcription polymerase chain reaction (RT-PCR). ACTB was used as the loading control. Representative images of the 3 independent experiments are shown