High retinoid X receptor expression in JEG-3 choriocarcinoma cells: Involvement in cell function modulation by retinoids

✍ Scribed by Jean Guibourdenche; Sylvie Roulier; Cécile Rochette-Egly; Danièle Evain-Brion

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 201 KB
• Volume: 176
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199809)176:3<595::aid-jcp16>3.0.co;2-z

✦ Synopsis

Retinoic acid (RA) is an important mediator of cell differentiation. It stimulates hCG secretion by JEG-3 choriocarcinoma cells in vitro after a time lag. The first aim of this study was to characterize which types of retinoid receptors (RARs and RXRs) are present in JEG-3 cells. Using Western blot analysis and immunocytochemistry with specific antibodies as well as Northern blot analysis, we found that JEG-3 cells expressed RARa and RXRa, the latter being the predominant receptor. We then analyzed the action on cell proliferation and hCG secretion of the physiological retinoids all-trans RA (RA) and 9 cis RA as well as synthetic retinoids with specific affinity for RARa and RXRa. All these retinoids were potent inhibitors of cell growth, maximal inhibition (72 { 2%) being observed after 4 days of treatment with Ro 25, a RXRa specific ligand. Within 24 h, 9 cis RA and Ro 25 stimulated hCG secretion, and maximal stimulation (1,472 { 10%) occurred at 48 h with the RXRa-specific ligand. The RARa-specific ligand also stimulated hCG secretion but to a lower extend and after a delay of 48 h. These results suggest a predominant role of RXRa in mediating the biological effects of retinoids on JEG-3 cells and the possible induction by RA itself of the metabolic pathway leading to 9 cis RA.