Glioma initiating cells form a differentiation niche via the induction of extracellular matrices and integrin αV

PLoS One. 2013 May 21;8(5):e59558. doi: 10.1371/journal.pone.0059558. Print 2013.

Abstract

Glioma initiating cells (GICs) are considered responsible for the therapeutic resistance and recurrence of malignant glioma. To clarify the molecular mechanism of GIC maintenance/differentiation, we established GIC clones having the potential to differentiate into malignant gliomas, and subjected to DNA microarray/iTRAQ based integrated proteomics. 21,857 mRNAs and 8,471 proteins were identified and integrated into a gene/protein expression analysis chart. Gene Ontology analysis revealed that the expression of cell adhesion molecules, including integrin subfamilies, such as α2 and αV, and extracellular matrices (ECMs), such as collagen IV (COL4), laminin α2 (LAMA2), and fibronectin 1 (FN), was significantly upregulated during serum-induced GIC differentiation. This differentiation process, accompanied by the upregulation of MAPK as well as glioma specific proteins in GICs, was dramatically accelerated in these ECM (especially FN)-coated dishes. Integrin αV blocking antibody and RGD peptide significantly suppressed early events in GIC differentiation, suggesting that the coupling of ECMs to integrin αV is necessary for GIC differentiation. In addition, the expression of integrin αV and its strong ligand FN was prominently increased in glioblastomas developed from mouse intracranial GIC xenografts. Interestingly, during the initial phase of GIC differentiation, the RGD treatment significantly inhibited GIC proliferation and raised their sensitivity against anti-cancer drug temozolomide (TMZ). We also found that combination treatments of TMZ and RGD inhibit glioma progression and lead the longer survival of mouse intracranial GIC xenograft model. These results indicate that GICs induce/secrete ECMs to develop microenvironments with serum factors, namely differentiation niches that further stimulate GIC differentiation and proliferation via the integrin recognition motif RGD. A combination of RGD treatment with TMZ could have the higher inhibitory potential against the glioma recurrence that may be regulated by the GICs in the differentiation niche. This study provides a new perspective for developing therapeutic strategies against the early onset of GIC-associated glioma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain Neoplasms / genetics
  • Brain Neoplasms / metabolism
  • Brain Neoplasms / pathology*
  • Carcinogenesis / drug effects
  • Carcinogenesis / pathology
  • Cell Adhesion / drug effects
  • Cell Differentiation* / drug effects
  • Cell Movement / drug effects
  • Cell Survival / drug effects
  • Dacarbazine / analogs & derivatives
  • Dacarbazine / pharmacology
  • Dacarbazine / therapeutic use
  • Disease Progression
  • Extracellular Matrix / drug effects
  • Extracellular Matrix / metabolism*
  • Fibronectins / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Ontology
  • Glioma / genetics
  • Glioma / metabolism*
  • Glioma / pathology*
  • Humans
  • Integrin alphaV / metabolism*
  • Mice
  • Neoplasm Proteins / metabolism
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology*
  • Oligopeptides / pharmacology
  • Oligopeptides / therapeutic use
  • Proteomics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reproducibility of Results
  • Spheroids, Cellular / metabolism
  • Spheroids, Cellular / pathology
  • Survival Analysis
  • Temozolomide

Substances

  • Fibronectins
  • Integrin alphaV
  • Neoplasm Proteins
  • Oligopeptides
  • RNA, Messenger
  • arginyl-glycyl-aspartic acid
  • Dacarbazine
  • Temozolomide

Grant support

This study was supported by grants from the Ministry of Health, Labor and Welfare of Japan (NA), Houga Research (NA) (grant number 23659693), Exploratory Research for Young Scientists (B) (A.NN) (grant number 22700905) from the Ministry of Education, Science, Sports, and Culture of Japan; and from the COE project B of Kumamoto University for proteomic research and education (NA) (http://www.jsps.go.jp/english/index.html). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.