Expression of the new CXCL12 receptor, CXCR7, in gliomas

Chiara Calatozzolo, Alessandra Canazza, Bianca Pollo, Erica Di Pierro, Emilio Ciusani, Emanuela Maderna, Eduardo Salce, Valentina Sponza, Simona Frigerio, Francesco Di Meco, Sergio Schinelli, Andrea Salmaggi

Research output: Contribution to journalArticlepeer-review

Abstract

Gliomas are very invasive brain tumors with poor prognosis and therefore any attempt to limit tumor cell dissemination in the brain is expected to improve glioma treatment. The recent deorphanization of CXCR7 as additional receptor for CXCL12 and CXCL11 has raised key issues on its interaction with the CXCL12/CXCR4 axis as a mechanism to modulate glioma cell migration. In this work we investigated protein and mRNA expression of the two chemokines CXCL12 and CXCL11, together with their receptors CXCR4 and CXCR7 in human glioma specimens and cell lines by immunohistochemistry, flow cytometry and quantitative real-time PCR. The main purpose of this study was to find out whether and at what extent CXCR4 and CXCR7 are differentially expressed in glioma cells. In human glioma specimens the levels of CXCL11 and CXCR4 mRNA were significantly higher in glioblastomas compared to non-tumor controls or low grade gliomas, whilst no difference was found for CXCL12 and CXCR7 mRNA expression. In cell lines, flow cytometry and immunocytochemical experiments showed CXCR4 was mainly expressed irrespective of its membrane or intracellular localization. In contrast, a predominant intracellular localization together with a negligible membrane expression of CXCR7 was found in all cells examined. In in vitro experiments CXCR4 and CXCR7 antagonists and the silencing of CXCR4 showed complete inhibition of glioma proliferation. Our findings, in agreement with previous data, suggest that in human glioma cells the prevalent intracellular localization of CXCR7 might modulate the functionality of CXCL11/12 either acting as a scavenger for these chemokines or interfering with the signaling pathways activated by the stimulation of CXCR4.

Original languageEnglish
Pages (from-to)242-253
Number of pages12
JournalCancer Biology and Therapy
Volume11
Issue number2
DOIs
Publication statusPublished - Jan 15 2011

Keywords

  • Chemokine
  • CXCL11
  • CXCL12
  • CXCR4
  • CXCR7
  • Glioma
  • Immunohistochemistry

ASJC Scopus subject areas

  • Cancer Research
  • Oncology
  • Molecular Medicine
  • Pharmacology

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