Prospective Isolation and Comparison of Human Germinal Matrix and Glioblastoma EGFR+ Populations with Stem Cell Properties

Characterization of non-neoplastic and malignant human stem cell populations in their native state can provide new insights into gliomagenesis. Here we developed a purification strategy to directly isolate EGFR+/– populations from human germinal matrix (GM) and adult subventricular zone autopsy tissues, and from de-novo glioblastoma (GBM) resections, enriching for cells capable of binding EGF ligand (LBEGFR+), and uniquely compared their functional and molecular properties. LBEGFR+ populations in both GM and GBM encompassed all sphere-forming cells and displayed proliferative stem cell properties in vitro. In xenografts, LBEGFR+ GBM cells showed robust tumor initiation and progression to high-grade, infiltrative gliomas. Whole transcriptome sequencing analysis confirmed enrichment of proliferative pathways in both developing and neoplastic freshly isolated EGFR+ populations, and identified both unique and shared sets of genes. The ability to prospectively isolate stem cell populations using native ligand-binding ability opens new doors into understanding both normal human progenitors and tumor cell biology. We performed full transcriptome sequencing by RNA-seq on freshly isolated EGFR+ and EGFR– populations from human brain germinal matrix (GM, n=3) and from human glioblastoma (GBM, n=3) resections. Three biological replicates were sequenced for each group: GM EGFR+, GM EGFR–, GBM EGFR+, and GBM EGFR–. Sequencing was performed on Illumina HiSeq 2500 (125bp pair-end sequencing, 38-50mil paired-end reads/sample).