Genome-Wide Profiling Identified a Set of miRNAs that Are Differentially Expressed in Glioblastoma Stem Cells and Normal Neural Stem Cells

Ming-Fei Lang,Kiyohito Murai,Xiaoxuan Liu,Jiehua Zhou,Jinhui Wang,Su Yang,Ling Peng,Guoqiang Sun,Hanlin Gao,Christine E Brown,Chunnian Zhao,John J Rossi,Xiwei Wu,Yanhong Shi

doi:10.1371/journal.pone.0036248

Abstract

A major challenge in cancer research field is to define molecular features that distinguish cancer stem cells from normal stem cells. In this study, we compared microRNA (miRNA) expression profiles in human glioblastoma stem cells and normal neural stem cells using combined microarray and deep sequencing analyses. These studies allowed us to identify a set of 10 miRNAs that are considerably up-regulated or down-regulated in glioblastoma stem cells. Among them, 5 miRNAs were further confirmed to have altered expression in three independent lines of glioblastoma stem cells by real-time RT-PCR analysis. Moreover, two of the miRNAs with increased expression in glioblastoma stem cells also exhibited elevated expression in glioblastoma patient tissues examined, while two miRNAs with decreased expression in glioblastoma stem cells displayed reduced expression in tumor tissues. Furthermore, we identified two oncogenes, NRAS and PIM3, as downstream targets of miR-124, one of the down-regulated miRNAs; and a tumor suppressor, CSMD1, as a downstream target of miR-10a and miR-10b, two of the up-regulated miRNAs. In summary, this study led to the identification of a set of miRNAs that are differentially expressed in glioblastoma stem cells and normal neural stem cells. Characterizing the role of these miRNAs in glioblastoma stem cells may lead to the development of miRNA-based therapies that specifically target tumor stem cells, but spare normal stem cells.

Highlights

According to the World Health Organization (WHO) classification of tumors, a grading scheme, which represents a malignancy scale and a key factor influencing the choice of therapies, has been successfully applied to astrocytomas, the most common type of glioma [1]
Differential miRNA expression in glioblastoma stem cells and normal neural stem cells In order to identify miRNAs that are differentially expressed in glioblastoma stem cells and normal neural stem cells, we established three primary glioblastoma stem cell lines and three normal human neural stem cell lines to determine if there were significant differences in miRNA expression in tumor stem cells from normal stem cells
Human primary glioblastoma stem cells were derived from newly diagnosed glioblastoma multiforme IV patients and cultured in DMEM/F12 media supplemented with epithelial growth factor (EGF), fibroblast growth factor (FGF), and B27 supplement

Summary

Introduction

According to the World Health Organization (WHO) classification of tumors, a grading scheme, which represents a malignancy scale and a key factor influencing the choice of therapies, has been successfully applied to astrocytomas, the most common type of glioma [1]. The goal of our research is to identify novel molecular targets for this malignant tumor, and glioblastoma is the main interest of this study. Recent studies have led to the hypothesis that glioblastomas are maintained by a small population of cancer stem cells that retain stem cell properties, are highly tumorigenic, and display increased resistance to radiation and chemotherapy [2,3,4]. These treatmentresistant tumor cell subpopulations are the cell populations that effective therapies must target [4]

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