title: Intranuclear crosstalk between extracellular regulated kinase1/2 and signal transducer and activator of transcription 3 regulates JEG-3 choriocarcinoma cell invasion and proliferation.
abstract: Invasiveness of trophoblast and choriocarcinoma cells is in part mediated via leukemia inhibitory factor- (LIF-) induced activation of signal transducer and activator of transcription 3 (STAT3). The regulation of STAT3 phosphorylation at its ser727 binding site, possible crosstalk with intracellular MAPK signaling, and their functional implications are the object of the present investigation. JEG-3 choriocarcinoma cells were cultured in presence/absence of LIF and the specific ERK1/2 inhibitor (U0126). Phosphorylation of signaling molecules (p-STAT3 (ser727 and tyr705) and p-ERK1/2 (thr 202/tyr 204)) was assessed per Western blot. Immunocytochemistry confirmed results, but also pinpointed the location of phosphorylated signaling molecules. STAT3 DNA-binding capacity was studied with a colorimetric ELISA-based assay. Cell viability and invasion capability were assessed by MTS and Matrigel assays. Our results demonstrate that LIF-induced phosphorylation of STAT3 (tyr705 and ser727) is significantly increased after blocking ERK1/2. STAT3 DNA-binding capacity and cell invasiveness are enhanced after LIF stimulation and ERK1/2 blockage. In contrast, proliferation is enhanced by LIF but reduced after ERK1/2 inhibition. The findings herein show that blocking ERK1/2 increases LIF-induced STAT3 phosphorylation and STAT3 DNA-binding capacity by an intranuclear crosstalk, which leads to enhanced invasiveness and reduced proliferation.
authors.affiliation: Placenta Lab, Department of Obstetrics, University Hospital Jena, Bachstraße 18, 07743 Jena, Germany.
authors.forename: Diana M
authors.initials: DM
authors.lastname: Morales-Prieto
authors.forename: Stephanie
authors.initials: S
authors.lastname: Ospina-Prieto
authors.forename: Wittaya
authors.initials: W
authors.lastname: Chaiwangyen
authors.forename: Maja
authors.initials: M
authors.lastname: Weber
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hölters
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Schleussner
authors.forename: Justine S
authors.initials: JS
authors.lastname: Fitzgerald
authors.forename: Udo R
authors.initials: UR
authors.lastname: Markert
mesh_terms: D002070:Butadienes / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002822:Choriocarcinoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D053605:Leukemia Inhibitory Factor / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation; D011485:Protein Binding; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D050796:STAT3 Transcription Factor / Q000378:metabolism*
chemical_list: D002070:Butadienes; C507837:LIF protein, human; D053605:Leukemia Inhibitory Factor; D009570:Nitriles; D047428:Protein Kinase Inhibitors; D050796:STAT3 Transcription Factor; C113580:U 0126; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3