Differentiated glioblastoma cells accelerate tumor progression by shaping the tumor microenvironment via CCN1-mediated macrophage infiltration

Atsuhito Uneda,Atsushi Fujimura,Yasuhiko Hattori,Joji Ishida,Nobushige Tsuboi,Yusuke Tomita,Kentaro Fujii,Shuichiro Hirano,Kazuhiko Kurozumi,Keigo Makino,Atsunori Kamiya,Yuji Matsumoto,Yoshihiro Otani,Yosuke Shimazu,Isao Date

doi:10.1186/s40478-021-01124-7

Abstract

Glioblastoma (GBM) is the most lethal primary brain tumor characterized by significant cellular heterogeneity, namely tumor cells, including GBM stem-like cells (GSCs) and differentiated GBM cells (DGCs), and non-tumor cells such as endothelial cells, vascular pericytes, macrophages, and other types of immune cells. GSCs are essential to drive tumor progression, whereas the biological roles of DGCs are largely unknown. In this study, we focused on the roles of DGCs in the tumor microenvironment. To this end, we extracted DGC-specific signature genes from transcriptomic profiles of matched pairs of in vitro GSC and DGC models. By evaluating the DGC signature using single cell data, we confirmed the presence of cell subpopulations emulated by in vitro culture models within a primary tumor. The DGC signature was correlated with the mesenchymal subtype and a poor prognosis in large GBM cohorts such as The Cancer Genome Atlas and Ivy Glioblastoma Atlas Project. In silico signaling pathway analysis suggested a role of DGCs in macrophage infiltration. Consistent with in silico findings, in vitro DGC models promoted macrophage migration. In vivo, coimplantation of DGCs and GSCs reduced the survival of tumor xenograft-bearing mice and increased macrophage infiltration into tumor tissue compared with transplantation of GSCs alone. DGCs exhibited a significant increase in YAP/TAZ/TEAD activity compared with GSCs. CCN1, a transcriptional target of YAP/TAZ, was selected from the DGC signature as a candidate secreted protein involved in macrophage recruitment. In fact, CCN1 was secreted abundantly from DGCs, but not GSCs. DGCs promoted macrophage migration in vitro and macrophage infiltration into tumor tissue in vivo through secretion of CCN1. Collectively, these results demonstrate that DGCs contribute to GSC-dependent tumor progression by shaping a mesenchymal microenvironment via CCN1-mediated macrophage infiltration. This study provides new insight into the complex GBM microenvironment consisting of heterogeneous cells.

Highlights

Glioblastoma (GBM) is the most aggressive and lethal primary brain tumor [33]
H3K27ac chip sequencing data were derived from NCBI Gene Expression Omnibus GSE54047. b Metaplot showing average H3K27ac signals of all differentiated GBM cells (DGCs)-specific enhancers in three matched GBM stem-like cells (GSCs) and DGCs (MGG4, MGG6, and MGG8)
H3K27ac chip sequencing data were derived from NCBI Gene Expression Omnibus GSE54047. c De novo and known motif enrichment analysis of DGC-specific enhancers defined in a, b displayed enrichment for transcriptional motifs of the TEA domain family member (TEAD) transcription factor family. d Gene set enrichment analysis (GSEA) analysis of Yes-associated protein (YAP)-related signatures upregulated in DGCs compared with GSCs

Summary

Introduction

Glioblastoma (GBM) is the most aggressive and lethal primary brain tumor [33]. The basis of therapeutic failure is the significant inter- and intra-tumoral heterogeneity of GBM [34, 38, 48, 55, 56]. GBMs have been stratified by bulk gene expression profiles into at least three subtypes, namely proneural, classical, and mesenchymal subtypes [55, 56]. Among these subtypes, the mesenchymal subtype is associated with the worst prognosis and the presence of tumor-associated macrophages/microglia [39, 56]

Methods

Results

Conclusion