Connexin 30 expression inhibits growth of human malignant gliomas but protects them against radiation therapy

M. Artesi, J. Kroonen, M. Bredel, M.T. Nguyen-Khac, M. Deprez, L. Schoysman, Christophe Poulet, A. Chakravarti, H. Kim, D.M. Scholtens, T. Seute, B. Rogister, V. Bours, P.A. Robe

Research output: Contribution to journalArticleAcademicpeer-review


Background. Glioblastomas remain ominous tumors that almost invariably escape treatment. Connexins are a family of transmembrane, gap junction-forming proteins, some members of which were reported to act as tumor suppressors and to modulate cellular metabolism in response to cytotoxic stress. Methods. We analyzed the copy number and expression of the connexin (Cx)30 gene gap junction beta-6 (GJB6), as well as of its protein immunoreactivity in several public and proprietary repositories of glioblastomas, and their influence on patient survival. We evaluated the effect of the expression of this gap junction protein on the growth, DNA repair and energy metabolism, and treatment resistance of these tumors. Results. The GJB6 gene was deleted in 25.8% of 751 analyzed tumors and mutated in 15.8% of 158 tumors. Cx30 immunoreactivity was absent in 28.9% of 145 tumors. Restoration of Cx30 expression in human glioblastoma cells reduced their growth in vitro and as xenografts in the striatum of immunodeficient mice. Cx30 immunoreactivity was, however, found to adversely affect survival in 2 independent retrospective cohorts of glioblastoma patients. Cx30 was found in clonogenic assays to protect glioblastoma cells against radiation-induced mortality and to decrease radiation-induced DNA damage. This radioprotection correlated with a heat shock protein 90-dependent mitochondrial translocation of Cx30 following radiation and an improved ATP production following this genotoxic stress. Conclusion. These results underline the complex relationship between potential tumor suppressors and treatment resistance in glioblastomas and single out GJB6/Cx30 as a potential biomarker and target for therapeutic intervention in these tumors. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved.
Original languageEnglish
Pages (from-to)392-406
Number of pages15
Issue number3
Publication statusPublished - 2015


  • adenosine triphosphate
  • connexin 30
  • heat shock protein 90
  • messenger RNA
  • BIRC5 protein, human
  • gap junction protein
  • GJB6 protein, human
  • inhibitor of apoptosis protein
  • tumor marker, animal experiment
  • animal model
  • animal tissue
  • Article
  • cancer growth
  • cancer radiotherapy
  • connexin 30 gene
  • controlled study
  • DNA repair
  • energy metabolism
  • gene deletion
  • gene dosage
  • gene expression
  • glioblastoma
  • human
  • human cell
  • human tissue
  • immunoreactivity
  • in vitro study
  • in vivo study
  • mouse
  • nonhuman
  • protein expression
  • protein function
  • protein transport
  • tumor xenograft
  • animal
  • Brain Neoplasms
  • cell proliferation
  • genetics
  • glioma
  • Kaplan Meier method
  • metabolism
  • mitochondrion
  • mortality
  • tumor cell line
  • xenograft, Animals
  • Biomarkers, Tumor
  • Cell Line, Tumor
  • Cell Proliferation
  • Connexins
  • Gene Deletion
  • Glioma
  • Heterografts
  • HSP90 Heat-Shock Proteins
  • Humans
  • Inhibitor of Apoptosis Proteins
  • Kaplan-Meier Estimate
  • Mice
  • Mitochondria
  • RNA, Messenger


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