Effects of prolactin on intracellular calcium concentration and cell proliferation in human glioma cells.
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.
Ducret
Thomas
T
Laboratoire de Neurophysiologie, Centre National de la Recherche Scientifique UMR 5543, Université de Bordeaux 2, France.
Boudina
Sihem
S
Sorin
Bruno
B
Vacher
Anne Marie
AM
Gourdou
Isabelle
I
Liguoro
Dominique
D
Guerin
Jean
J
Bresson-Bepoldin
Laurence
L
Vacher
Pierre
P
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
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