EGF increases retinoid X receptor-alpha expression in human trophoblastic cells in culture: relationship with retinoic acid induced human chorionic gonadotropin secretion.
In the present study, the effect of retinoic acid (RA) and epidermal growth factor (EGF) on the functions of human trophoblastic cells in culture were analysed. In these cells, RA potentiated the hCG secretion increase induced by EGF. To gain a better understanding of such a synergistic effect, the expression of retinoic acid receptors (RAR alpha and beta) and retinoid X receptor (RXR alpha) was studied by immunoblotting in RA- and EGF-treated cells. EGF treatment specifically increased the level of RXR alpha protein and RXR alpha transcripts. In parallel, we demonstrated that the choriocarcinoma cells JEG 3, which respond to RA by an increase in hCG secretion, express constitutively high levels of RXR alpha protein. Furthermore, RXR alpha-transfected trophoblastic cells also become RA responsive for hCG secretion. All these data suggest that RXR alpha expression is modulated by EGF, and may be involved in the effect of RA on hCG secretion.
Roulier
S
S
INSERM U427, Faculté des Sciences Pharmaceutiques et Biologiques de Paris, Université René Descartes-Paris V, France.
Rochette-Egly
C
C
Alsat
E
E
Dufour
S
S
Porquet
D
D
Evain-Brion
D
D
D002461:Cell Line, Transformed; D002478:Cells, Cultured; D006063:Chorionic Gonadotropin / Q000378:metabolism*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D005260:Female; D006801:Humans; D011247:Pregnancy; D018168:Receptors, Retinoic Acid / Q000096:biosynthesis* / Q000235:genetics; D047488:Retinoid X Receptors; D014157:Transcription Factors / Q000096:biosynthesis* / Q000235:genetics; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology*; D014327:Trophoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D006063:Chorionic Gonadotropin; D018168:Receptors, Retinoic Acid; D047488:Retinoid X Receptors; D014157:Transcription Factors; D014212:Tretinoin; D004815:Epidermal Growth Factor