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

Abstract

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 capacity opens new doors onto understanding both normal human development and tumor cell biology.

Keywords: EGFR; FACS; RNA-seq; germinal matrix; glioblastoma; glioma stem cells; neural stem cells; neurosphere; transcriptome; tumor initiation.