Figure 4.
MLL1 expression is elevated in glioma stem cells compared to non-stem glioma cells. Patient-derived glioma specimens were dissociated and enriched for GSCs as described previously.9 (a) A PCR screen for epigenetic modifiers determined that out of 96 epigenetic regulators, only MLL1 demonstrated consistent preferential expression in the GSCs when RNA was isolated from 4121 and 387 GSCs, and non-stem cell fractions were compared. (b) These data were confirmed with total lysates immunoblotted for MLL1. (c) Real-time PCR demonstrated that MLL1 mRNA was consistently upregulated in GSC fractions. (d) The cancer stem cell nature of the GSC fractions was confirmed through elevation of Olig2 mRNA. All mRNA levels were normalized to actin. *P<0.001; **P<0.05. (e) Colocalization of MLL1 and putative GSC marker, CD133, was visualized by staining of sectioned neurospheres in three different patient-derived specimens