Fig. 1

Differential expression of NK cell ligands and susceptibility to NK cell-mediated cytotoxicity between patient-derived mesenchymal and proneural glioma stem cell populations. (A) Principal component analysis (PCA) of total transcriptomes of indicated cells: proneural GSCs (PN), mesenchymal GSCs (MES) and astrocytes. (B-C) In silico analysis of mRNA expression levels (microarrays) for NK cell ligands in a panel of PN and MES GSCs and Astrocytes. Activating NK ligand transcripts (B) and transcripts for multifunctional NK ligands (C). (D-E) Differential cell surface expression of NK ligands interacting with cytotoxic NKG2D by MES-GSCs and PN-GSCs (FACS); MICA (D) and ULBP-2/5/6 (E). GSCs were assayed with or without pretreatment with temozolomide (TMZ). MICA and ULBP-2/5/6 protein levels were expressed as median fluorescent intensity +/- SEM, for n = 3–5 independent repetitions, p values were determined for group comparisons by unpaired two-tailed t-test, p < 0.0001 (F) NK cell specific target cell (GSC) lysis analyzed by bioluminescence assay. GSCs were incubated with NK92MI human immortalized NK cells for 4 h at indicated ratios. Experiments were performed at least 3 times, **** p < 0.0001 as determined for group comparison between PN and MES time points by one way ANOVA with Tukey’s multiple comparison test +/- SEM