title: Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cells.
abstract: Prolactin (PRL) has several physiological effects on peripheral tissues and the brain. This hormone acts via its membrane receptor (PRL-R) to induce cell differentiation or proliferation. Using reverse transcription-polymerase chain reaction (RT-PCR) combined with Southern blot analysis, we detected PRL-R transcripts in a human glioma cell line (U87-MG) and in primary cultured human glioblastoma cells. These transcripts were deleted or not in their extracellular domains. We examined the effects of PRL on intracellular free Ca2+ concentration ([Ca2+](i)) in these cells in order to improve our understanding of the PRL transduction mechanism, which is still poorly documented. [Ca2+](i) was measured by microspectrofluorimetry using indo-1 as the Ca2+ fluorescent probe. Spatiotemporal aspects of PRL-induced Ca2+ signals were investigated using high-speed fluo-3 confocal imaging. We found that physiological concentrations (0.4-4 nM) of PRL-stimulated Ca2+ entry and intracellular Ca2+ mobilization via a tyrosine kinase-dependent mechanism. The two types of Ca2+ responses observed were distinguishable by their kinetics: one showing a slow (type I) and the other a fast (type II) increase in [Ca2+](i). The amplitude of PRL-induced Ca2+ increases may be sufficient to provoke several physiological responses, such as stimulating proliferation. Furthermore, PRL induced a dose-dependent increase in [3H]thymidine incorporation levels and in cellular growth and survival, detected by the MTT method. These data indicate that PRL induced mitogenesis of human glioma cells.
authors.affiliation: Laboratoire de Neurophysiologie, Centre National de la Recherche Scientifique UMR 5543, Université de Bordeaux 2, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ducret
authors.forename: Sihem
authors.initials: S
authors.lastname: Boudina
authors.forename: Bruno
authors.initials: B
authors.lastname: Sorin
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: Vacher
authors.forename: Isabelle
authors.initials: I
authors.lastname: Gourdou
authors.forename: Dominique
authors.initials: D
authors.lastname: Liguoro
authors.forename: Jean
authors.initials: J
authors.lastname: Guerin
authors.forename: Laurence
authors.initials: L
authors.lastname: Bresson-Bepoldin
authors.forename: Pierre
authors.initials: P
authors.lastname: Vacher
mesh_terms: D001932:Brain Neoplasms / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D053614:Janus Kinase 2; D008297:Male; D011388:Prolactin / Q000378:metabolism* / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger / Q000378:metabolism; D011981:Receptors, Prolactin / Q000819:agonists / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011981:Receptors, Prolactin; D011388:Prolactin; D004247:DNA; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; D053614:Janus Kinase 2; D000252:Calcium-Transporting ATPases; D002118:Calcium