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.

Oncostatin M and leukaemia inhibitory factor trigger signal transducer and activator of transcription 3 and extracellular signal-regulated kinase 1/2 pathways but result in heterogeneous cellular responses in trophoblast cells

“…It can be argued that the concentrations used in the present study were lower than in other studies; for example, Suman et al (2013) found that 50 ng mL À1 LIF increased the invasion of HTR-8/SVneo cells. Nevertheless, the concentrations used in the present study enhanced the invasiveness of the choriocarcinoma-derived cell lines JEG-3 and ACH-3P, which is in line with a previous report (Morales-Prieto et al 2013). Conversely, it can be argued that the origin of HTR-8/SVneo cells may be responsible for this cellular response.…”

“…Only in ACH-3P cells did OSM induce a more intensive phosphorylation of ERK1/2 than LIF. Previously, we reported that inhibition of ERK by U0126 significantly decreased JEG-3 and HTR-8/SVneo proliferation and increased JEG-3 invasiveness (Prakash et al 2011;Morales-Prieto et al 2013). Invasion of trophoblast cells into the decidua is essential for successful implantation and placentation (Knöfler and Pollheimer 2012).…”

“…In all experiments, the concentration of LIF and OSM used was 10 ng mL À1 . We chose this concentration for both cytokines in all experiments based on previous experiences with LIF Morales-Prieto et al 2013), in contrast with another study that used a twofold higher concentration of OSM (Ko et al 2012). …”

The Roles of p38 MAPK and ERK1/2 in Coplanar Polychlorinated Biphenyls-Induced Apoptosis of Human Extravillous Cytotrophoblast-Derived Transformed Cells

“…MAPK signaling pathways mediate the intracellular signaling associated with a variety of cellular physiological process, including the morphological and functional differentiation of villous trophoblasts, and have been proven to be important for the induction of cytotoxicity responses [28][29][30][31]. Thus, to identify the potential mechanisms that lead to cytotoxic responses of HTR-8/SVneo and HPT-8 cells to Co-PCBs, we demonstrated the roles members of the MAPK signal cascades, including ERK1/2 and p38 kinase.…”

Kidney-Replenishing Herb Induces SOCS-3 Expression via ERK/MAPK Pathway and Improves Growth of the First-Trimester Human Trophoblast Cells

“…An interesting study reported by Isobe and colleagues showed that MEK antagonist could inhibit SOCS-3 expression of the undifferentiated rat trophoblast-like cell line [12]. Another study has demonstrated that SOCS-3 binds and inactivates RasGAP, a negative regulator of Ras signaling, leading to increased Ras/MAPK pathway activity in human JEG-3 trophoblastic cells [13]. These data suggest that the activation of ERK1/2/MAPK pathway signal pathway may be related to SOCS-3 expression.…”