Identification of key signaling molecules involved in the activation of the swelling-activated chloride current in human glioblastoma cells

Luigi Catacuzzeno, Antonio Michelucci, Luigi Sforna, Francesco Aiello, Miriam Sciaccaluga, Bernard Fioretti, Emilia Castigli, Fabio Franciolini

Research output: Contribution to journalArticlepeer-review

Abstract

The swelling-activated chloride current (I Cl,Vol) is abundantly expressed in glioblastoma (GBM) cells, where it controls cell volume and invasive migration. The transduction pathway mediating I Cl,Vol activation in GBM cells is, however, poorly understood. By means of pharmacological and electrophysiological approaches, on GL-15 human GBM cells we found that I Cl,Vol activation by hypotonic swelling required the activity of a U73122-sensitive phospholipase C (PLC). I Cl,Vol activation could also be induced by the membrane-permeable diacylglycerol (DAG) analog OAG. In contrast, neither calcium (Ca2+) chelation by BAPTA-AM nor changes in PKC activity were able to affect I Cl,Vol activation by hypotonic swelling. We further found that R59022, an inhibitor of diacylglycerol kinase (DGK), reverted I Cl,Vol activation, suggesting the involvement of phosphatidic acid. In addition, I Cl,Vol activation required the activity of a EHT1864-sensitive Rac1 small GTPase and the resulting actin polymerization, as I Cl,Vol activation was prevented by cytochalasin B. We finally show that I Cl,Vol can be activated by the promigratory fetal calf serum in a PLC- and DGK-dependent manner. This observation is potentially relevant because blood serum can likely come in contact with glioblastoma cells in vivo as a result of the tumor-related partial breakdown of the blood-brain barrier. Given the relevance of I Cl,Vol in GBM cell volume regulation and invasiveness, the several key signaling molecules found in this study to be involved in the activation of the I Cl,Vol may represent potential therapeutic targets against this lethal cancer.

Original languageEnglish
Pages (from-to)45-55
Number of pages11
JournalJournal of Membrane Biology
Volume247
Issue number1
DOIs
Publication statusPublished - 2014

Keywords

  • Glioma cells
  • Signal transduction
  • Swelling-activated chloride current

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology

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