Functional endothelin ET B receptors are selectively expressed in human oligodendrogliomas.
Endothelin-1 (ET-1), a vasoactive and mitogenic peptide mainly produced by vascular endothelial cells, may be involved in the progression of several human tumors. Here, we present an immunohistochemical analysis of the expression pattern of ET-1 receptor subtypes (ET(A)-R and ET(B)-R) and a functional study of their potential role in human oligodendrogliomas and oligoastrocytomas. By comparison, we assessed the corresponding expression patterns of glioblastomas. Interestingly, a nuclear localization of ET-1 receptor subtypes (associated or not with a cytoplasmic labeling) was constantly observed in tumor cells from all three glioma types. Moreover, we noted a distinct receptor distribution in the different gliomas: a nuclear expression of ET(B)-R by tumor cells was found to be restricted to oligodendrogliomas and oligoastrocytomas, while a nuclear expression of ET(A)-R was only detected in tumor cells from some glioblastomas. Using primary cultures of oligodendroglial tumor cells, we confirmed the selective expression of nuclear ET(B)-R, together with a plasma membrane expression, and further demonstrated that this receptor was functionally coupled to intracellular signaling pathways known to be involved in cell survival and/or proliferation: extracellular signal-regulated kinase and focal adhesion kinase activation, actin cytoskeleton reorganization. In addition, impairment of ET(B)-R activation in these cells by in vitro treatment with an ET(B)-R-specific antagonist induced cell death. These data point to ET-1 as a possible survival factor for oligodendrogliomas via ET(B)-R activation and suggest that ET(B)-R-specific antagonists might constitute a potential therapeutic alternative for oligodendrogliomas.
Anguelova
E
E
Department of Cell Biology, Institut Cochin, INSERM U567, CNRS UMR 8104, IFR116, 22 rue Méchain, 75014 Paris, France.
Beuvon
F
F
Leonard
N
N
Chaverot
N
N
Varlet
P
P
Couraud
P-O
PO
Daumas-Duport
C
C
Cazaubon
S
S
D008841:Actin Cytoskeleton / Q000378:metabolism; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use; D001254:Astrocytoma / Q000188:drug therapy / Q000378:metabolism; D001932:Brain Neoplasms / Q000188:drug therapy / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D003593:Cytoplasm / Q000378:metabolism; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009837:Oligodendroglioma / Q000188:drug therapy / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology / Q000627:therapeutic use; D010880:Piperidines / Q000494:pharmacology / Q000627:therapeutic use; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D044022:Receptor, Endothelin A / Q000378:metabolism*; D044023:Receptor, Endothelin B / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D000959:Antihypertensive Agents; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1; D009842:Oligopeptides; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; C086539:BQ 788; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D048049:Extracellular Signal-Regulated MAP Kinases