Changes in chromatin state reveal ARNT2 at a node of a tumorigenic transcription factor signature driving glioblastoma cell aggressiveness

Abstract

Although a growing body of evidence indicates that phenotypic plasticity exhibited by glioblastoma cells plays a central role in tumor development and post-therapy recurrence, the master drivers of their aggressiveness remain elusive. Here we mapped the changes in active (H3K4me3) and repressive (H3K27me3) histone modifications accompanying the repression of glioblastoma stem-like cells tumorigenicity. Genes with changing histone marks delineated a network of transcription factors related to cancerous behavior, stem state, and neural development, highlighting a previously unsuspected association between repression of ARNT2 and loss of cell tumorigenicity. Immunohistochemistry confirmed ARNT2 expression in cell sub-populations within proliferative zones of patients’ glioblastoma. Decreased ARNT2 expression was consistently observed in non-tumorigenic glioblastoma cells, compared to tumorigenic cells. Moreover, ARNT2 expression correlated with a tumorigenic molecular signature at both the tissue level within the tumor core and at the single cell level in the patients’ tumors. We found that ARNT2 knockdown decreased the expression of SOX9, POU3F2 and OLIG2, transcription factors implicated in glioblastoma cell tumorigenicity, and repressed glioblastoma stem-like cell tumorigenic properties in vivo. Our results reveal ARNT2 as a pivotal component of the glioblastoma cell tumorigenic signature, located at a node of a transcription factor network controlling glioblastoma cell aggressiveness.Electronic supplementary materialThe online version of this article (10.1007/s00401-017-1783-x) contains supplementary material, which is available to authorized users.

Capture at the single cell level of metabolic modules distinguishing aggressive and indolent glioblastoma cells

“…Patient-derived cells (PDC) 6240**, R633 and 5706** were obtained from neurosurgical biopsy samples of distinct primary GBM, characterized and cultured as described [18,57]. (Table S1) was achieved as described [4,18]. Viable cell counting, gene expression analysis, intracranial xenografts, and bioluminescence imaging (Table S1) were performed as described [4,18]).…”

“…(Table S1) was achieved as described [4,18]. Viable cell counting, gene expression analysis, intracranial xenografts, and bioluminescence imaging (Table S1) were performed as described [4,18]). All experiments were performed using independent biological samples, each independently repeated at least three times with the exception of the xenograft experiments.…”

“…We developed a grouping method based on a molecular signature we previously identified [4]. The signature is composed of five transcription factors, ARNT2, POU3F2, OLIG2, SOX9 and SALL2, with co-varied expression in GBM tissues and cells [4]. The POU3F2, OLIG2 and SOX9 genes have regulatory elements with ARNT2 binding sites and are down-regulated upon ARNT2 knockdown [4].…”

“…The signature is composed of five transcription factors, ARNT2, POU3F2, OLIG2, SOX9 and SALL2, with co-varied expression in GBM tissues and cells [4]. The POU3F2, OLIG2 and SOX9 genes have regulatory elements with ARNT2 binding sites and are down-regulated upon ARNT2 knockdown [4]. Each signature element was demonstrated to be required for GBM cell tumorigenic properties [4,28,41,60].…”

“…The POU3F2, OLIG2 and SOX9 genes have regulatory elements with ARNT2 binding sites and are down-regulated upon ARNT2 knockdown [4]. Each signature element was demonstrated to be required for GBM cell tumorigenic properties [4,28,41,60]. We sought to use this signature to highlight subpopulations of cells in a tumorigenic state, expected to be present in all tumors.…”