Self-regulation of the endothelin receptor system in choriocarcinoma cells.
The human trophoblast secretes endothelin-1 (ET-1) and expresses ET receptors. The present study tested whether the transformed BeWo, JAR and JEG-3 choriocarcinoma cells: (1) secrete endothelin-1 (ET-1); (2) express both ET-A and ET-B receptor subtypes; and (3) have the potential to allow for autologous regulation of ET-receptor proteins. The cells were cultured for 24/48 h with or without 10% FCS and, in experiments on receptor regulation, with ET-1 (5-20 nM and 10 microM). ET-1 secretion was measured by RIA and receptor levels by immunoblotting. All cell types secreted ET-1 albeit at different levels and sensitivity to FCS. All cell lines expressed both ET-A (JEG-3>BeWo=JAR) and ET-B (JEG-3=JAR>BeWo) receptor subtypes, which could be up- and downregulated depending on ET-1 concentration, culture time and FCS presence. It is concluded that BeWo, JAR and JEG-3 choriocarcinoma cells secrete ET-1 and express both ET-A and ET-B receptor subtypes. The receptor levels can be regulated by ET-1. This provides the molecular basis for an autocrine system with the potential of autologous regulation of yet unidentified ET-1-induced functions.
Mauschitz
R
R
Department of Obstetrics and Gynecology, Karl-Franzens-University of Graz, Auenbruggerplatz 14, A-8036, Graz, Austria.
Cervar
M
M
Hahn
T
T
Pürstner
P
P
Desoye
G
G
D000918:Antibody Specificity; D002453:Cell Cycle; D002822:Choriocarcinoma / Q000378:metabolism* / Q000473:pathology; D019332:Endothelin-1 / Q000378:metabolism; D005260:Female; D006801:Humans; D011247:Pregnancy; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000276:immunology / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000378:metabolism* / Q000473:pathology
D019332:Endothelin-1; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin