title: CXCL12-induced glioblastoma cell migration requires intermediate conductance Ca2+-activated K+ channel activity.
abstract: The activation of ion channels is crucial during cell movement, including glioblastoma cell invasion in the brain parenchyma. In this context, we describe for the first time the contribution of intermediate conductance Ca(2+)-activated K (IK(Ca)) channel activity in the chemotactic response of human glioblastoma cell lines, primary cultures, and freshly dissociated tissues to CXC chemokine ligand 12 (CXCL12), a chemokine whose expression in glioblastoma has been correlated with its invasive capacity. We show that blockade of the IK(Ca) channel with its specific inhibitor 1-[(2-chlorophenyl) diphenylmethyl]-1H-pyrazole (TRAM-34) or IK(Ca) channel silencing by short hairpin RNA (shRNA) completely abolished CXCL12-induced cell migration. We further demonstrate that this is not a general mechanism in glioblastoma cell migration since epidermal growth factor (EGF), which also activates IK(Ca) channels in the glioblastoma-derived cell line GL15, stimulate cell chemotaxis even if the IK(Ca) channels have been blocked or silenced. Furthermore, we demonstrate that both CXCL12 and EGF induce Ca(2+) mobilization and IK(Ca) channel activation but only CXCL12 induces a long-term upregulation of the IK(Ca) channel activity. Furthermore, the Ca(2+)-chelating agent BAPTA-AM abolished the CXCL12-induced, but not the EGF-induced, glioblastoma cell chemotaxis. In addition, we demonstrate that the extracellular signal-regulated kinase (ERK)1/2 pathway is only partially implicated in the modulation of CXCL12-induced glioblastoma cell movement, whereas the phosphoinositol-3 kinase (PI3K) pathway is not involved. In contrast, EGF-induced glioblastoma migration requires both ERK1/2 and PI3K activity. All together these findings suggest that the efficacy of glioblastoma invasiveness might be related to an array of nonoverlapping mechanisms activated by different chemotactic agents.
authors.affiliation: Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy.
authors.forename: Miriam
authors.initials: M
authors.lastname: Sciaccaluga
authors.forename: Bernard
authors.initials: B
authors.lastname: Fioretti
authors.forename: Luigi
authors.initials: L
authors.lastname: Catacuzzeno
authors.forename: Francesca
authors.initials: F
authors.lastname: Pagani
authors.forename: Cristina
authors.initials: C
authors.lastname: Bertollini
authors.forename: Maria
authors.initials: M
authors.lastname: Rosito
authors.forename: Myriam
authors.initials: M
authors.lastname: Catalano
authors.forename: Giuseppina
authors.initials: G
authors.lastname: D'Alessandro
authors.forename: Antonio
authors.initials: A
authors.lastname: Santoro
authors.forename: Giampaolo
authors.initials: G
authors.lastname: Cantore
authors.forename: Davide
authors.initials: D
authors.lastname: Ragozzino
authors.forename: Emilia
authors.initials: E
authors.lastname: Castigli
authors.forename: Fabio
authors.initials: F
authors.lastname: Franciolini
authors.forename: Cristina
authors.initials: C
authors.lastname: Limatola
mesh_terms: D001932:Brain Neoplasms / Q000378:metabolism* / Q000473:pathology; D020013:Calcium Signaling; D045744:Cell Line, Tumor; D002614:Chelating Agents / Q000494:pharmacology; D054377:Chemokine CXCL12 / Q000378:metabolism*; D002633:Chemotaxis; D004815:Epidermal Growth Factor / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D009361:Neoplasm Invasiveness; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D026902:Potassium Channel Blockers / Q000494:pharmacology; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D019718:Receptors, CXCR4 / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D002614:Chelating Agents; D054377:Chemokine CXCL12; D004815:Epidermal Growth Factor; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D026902:Potassium Channel Blockers; D047428:Protein Kinase Inhibitors; D019718:Receptors, CXCR4; D011994:Recombinant Proteins; C515255:CXCL12 protein, human; C527276:CXCR4 protein, human