Transcriptional Differences between Normal and Glioma-Derived Glial Progenitor Cells Identify a Core Set of Dysregulated Genes

Glial progenitor cells (GPCs) are a potential source of malignant gliomas. We used A2B5-based sorting to extract tumorigenic GPCs from human gliomas spanning World Health Organization grades II–IV. Messenger RNA profiling identified a cohort of genes that distinguished A2B5+ glioma tumor progenitor cells (TPCs) from A2B5+ GPCs isolated from normal white matter. A core set of genes and pathways was substantially dysregulated in A2B5+ TPCs, which included the transcription factor SIX1 and its principal cofactors, EYA1 and DACH2. Small hairpin RNAi silencing of SIX1 inhibited the expansion of glioma TPCs in vitro and in vivo, suggesting a critical and unrecognized role of the SIX1-EYA1-DACH2 system in glioma genesis or progression. By comparing the expression patterns of glioma TPCs with those of normal GPCs, we have identified a discrete set of pathways by which glial tumorigenesis may be better understood and more specifically targeted. [Display omitted] •Gene expression in normal versus neoplastic A2B5+ glioma tumor progenitor cells (TPCs) was profiled•A2B5+ TPCs transit from proneural to mesenchymal phenotype with glioma progression•SIX1 and EYA1 are overexpressed in A2B5+ TPCs at all stages of glioma progression•Inhibition of SIX1 suppresses glioma TPC expansion in vitro and in vivo A discrete fraction of tumor progenitor cells (TPCs) may be responsible for the initiation, recurrence, and treatment resistance of glioma. To identify pathways to treat these tumors, Auvergne, Goldman, and colleagues compared the expression profiles of A2B5-defined glioma TPCs at varying stages of progression with those of normal adult human glial progenitor cells. They identify a discrete cohort of genes and pathways that are associated with the earliest stages of glioma formation and are maintained throughout progression. Targeting these pathways may permit more effective glioma treatment.