Regulation of 3 beta-hydroxysteroid dehydrogenase and 17 beta-hydroxysteroid dehydrogenase messenger ribonucleic acid levels by cyclic adenosine 3',5'-monophosphate and phorbol myristate acetate in human choriocarcinoma cells.
3 beta-Hydroxysteroid dehydrogenase (3 beta HSD) in human placenta converts 3 beta-hydroxy-5-ene steroids producing progesterone, whereas 17 beta-hydroxysteroid dehydrogenase (17 beta HSD) mediates the interconversion of estrone and estradiol. We first showed that the expression of type I 17 beta HSD (17 beta HSD-I) gene was undetectable in human JEG-3 cells. We then studied the effects of cAMP- and protein kinase-C-dependent pathways on the expression of 3 beta HSD-I and 17 beta HSD-II genes using an analog of cAMP [8-(4-chlorophenylthio)cAMP (8CPTcAMP)] and a protein kinase-C (PKC) activator, phorbol 12-myristate 13-acetate (PMA), in JEG-3 cells. Novel inhibitors of protein kinase-A (PKA) and PKC were also used. The 3 beta HSD cDNA probe hybridized to a single 1.7-kilobase (kb) 3 beta HSD mRNA species corresponding to the transcript of the 3 beta HSD-I gene. The 17 beta HSD cDNA probe hybridized to two 17 beta HSD transcripts of 1.3 and 2.2 kb. The 1.3-kb 17 beta HSD mRNA species was regulated, whereas the 2.2-kb species was constitutively expressed in JEG-3 cells. When JEG-3 cells were exposed to 8CPTcAMP or PMA, 3 beta HSD-I and 17 beta HSD-II gene transcriptions were increased in a dose- and time-dependent manner. Moreover, the combined effects of PMA and 8CPTcAMP on 3 beta HSD-I mRNA levels was additive and synergistic on 17 beta HSD-II mRNA levels. The mechanism by which cAMP activated accumulation of 3 beta HSD-I and 17 beta HSD-II mRNAs involved an activation of the cyclase. The effects of a cAMP-dependent kinase inhibitor and a diacylglycerol-dependent kinase inhibitor in JEG-3 cells indicated that cAMP acts on 3 beta HSD-I mRNA via a PKA-dependent mechanism, but on 17 beta HSD-II mRNA via another nonclassical cAMP-dependent mechanism. Finally, the effect of activation of both signaling pathways on expression of the 17 beta HSD-II gene as well as the effect of PMA on the 3 beta HSD-I gene did not require protein synthesis. These data provide strong evidence for the regulation of the 3 beta HSD-I and 17 beta HSD-II genes by cAMP and PKC and, thus, indicate an important endocrine and/or paracrine regulation of steroid hormone production in human placenta.
Department of Physiology, Laval University Centre Hospitalier de l'Université Laval Sainte-Foy, Québec, Canada.
Y
Y
Tremblay
C
C
Beaudoin
D015067:17-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics*; D015096:3-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D015152:Blotting, Northern; D002822:Choriocarcinoma / Q000201:enzymology; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D015342:DNA Probes; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008969:Molecular Sequence Data; D011493:Protein Kinase C / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis*; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013873:Thionucleotides / Q000494:pharmacology*; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
D015342:DNA Probes; D012333:RNA, Messenger; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D000242:Cyclic AMP; D015067:17-Hydroxysteroid Dehydrogenases; D015096:3-Hydroxysteroid Dehydrogenases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate