E-cadherin, as a negative regulator of invasive behavior of human trophoblast cells, is down-regulated by cyclosporin A via epidermal growth factor/extracellular signal-regulated protein kinase signaling pathway

Methanolic extract of Teucrium persicum up-regulates and induces the membrane restoration of E-cadherin protein in PC-3 cells

Teucrium persicum Boiss. an Iranian endemic plant is used in Iranian traditional medicine. E-cadherin transmembrane protein participates in adherens junctions and is the main partner for β-catenin protein. The GC-MS analysis was used to detect the chemical constituents of the methanolic extract. Its effects on the transcription of the E-cadherin encoding gene, cellular levels, and localization of E-cadherin protein in PC-3 cells were investigated. About 70 chemical constituents were identified. Indirect immunofluorescence microscopy and western blotting results revealed the restoration of E-cadherin protein at cell adhesion contact sites in cells treated with T. persicum extract. Gene expression studies revealed that the extract increased the transcription of the E-cadherin encoding gene in PC-3 cells. These results suggest that T. persicum extract may contain potent compounds that provide further support for the anticancer properties of T. persicum. Surely, detailed molecular investigations are needed to find the mechanism(s) behind these effects.

Epithelial-mesenchymal transition process during embryo implantation

The epithelial to mesenchymal transition (EMT) in endometrial epithelial and trophectoderm cells is essential for the progression of embryo implantation and its impairment could cause implantation failure. Therefore, EMT should be tightly regulated in both embryonic and endometrial cells during implantation. Studies reported the involvement of numerous factors in EMT regulation, including hormones, growth factors, transcription factors, microRNAs, aquaporins (AQPs), and ion channels. These factors act through different signaling pathways to affect the expression of epithelial and mesenchymal markers as well as the cellular cytoskeleton. Although the mechanisms involved in cancer cell EMT have been well studied, little is known about EMT during embryo implantation. Therefore, we comprehensively reviewed different factors that regulate the EMT, a key event required for the conceptus implantation to the endometrium.Summary sentence: Abnormal epithelial-mesenchymal transition (EMT) process within endometrial epithelial cells (EECs) or trophoblast cells can cause implantation failure. This process is regulated by various factors. Thus, the objective of this review was to summarize the effective factors on the EMT process during implantation.

Possible Role of TGF-β1, MMP-2, E-CAD, β-Catenin and Antioxidants in Pathogenesis of Placenta Accreta

Placenta accreta (PA) can be life-threatening due to postpartum hemorrhage and may lead to cesarean hysterectomy. We investigated the expression of Matrix metalloproteinase-2 (MMP-2), β-catenin, E-cadherin (E-CAD), transforming growth factor β1 (TGF-β1), glutathione peroxidase 1 (GPx-1), reduced glutathione (GSH) and superoxide dismutase (SOD) in PA compared to controls to determine if alterations may contribute to PA. Materials and methods: Twenty six PA and 31 controls were evaluated immunohistochemically for expression of MMP-2, β-catenin and E-CAD on villous and extravillous trophoblasts. TGF-β1 and GPx-1 mRNA levels were evaluated by rt-PCR. We measured biochemical levels of GSH and SOD. Results: Significant increases of MMP-2 immunoexpression, GPx-1 mRNA, SOD and GSH levels, decreases in immunoexpression of E-CAD and β-catenin and TGF-β1 mRNA were found in PA. Conclusion: These findings suggest that loss of cell-cell adhesion and increased antioxidants level may have a role in PA.

Effects of cyclosporine A on proliferation, invasion and migration of HTR-8/SVneo human extravillous trophoblasts

As shown in our previous study, cyclosporine A (CsA) promotes the proliferation, invasion and migration of villous trophoblasts, thus improving embryo implantation. In addition, the incidence of preeclampsia (PE) is decreased in patients with recurrent spontaneous abortion (RSA) and repeated implantation failure (RIF) treated with CsA during the first trimester. Abnormal function of extravillous trophoblasts (EVTs) in early pregnancy is recognized as the pathogenetic mechanism of PE. EVTs share homology and function with pre-villous trophoblasts and villous trophoblasts; thus, we hypothesized that CsA may have the same regulatory effect on EVTs. In this study, we investigated the effects of CsA on HTR-8/SVneo trophoblasts in the extravillous layer and explored the underlying mechanisms. QPCR and Western blot (WB) analyses were performed to detect expression alterations in relevant proliferation and invasion proteins in response to different concentrations of CsA. We used an Affymetrix IVT expression microarray to examine the target genes of CsA in preeclamptic placentas versus normal placentas. Our results showed that certain concentrations of CsA could promote the proliferation, invasion and migration of HTR8/SVneo cells. CsA was also found to promote the expression of titin, MMP9, EGFR, and PRR15. TRAIL may be a target gene for CsA-mediated regulation of EVTs. CONCLUSIONS: By promoting the expression of related proteins and regulating the functions of HTR8/SVneo cells, CsA can promote vascular recasting and placental function, which may affect the pathogenesis of PE.

Irisin induces trophoblast differentiation via AMPK activation in the human placenta

Irisin, an adipokine, regulates differentiation and phenotype in various cell types including myocytes, adipocytes, and osteoblasts. Circulating irisin concentration increases throughout human pregnancy. In pregnancy disorders such as preeclampsia and gestational diabetes mellitus, circulating irisin levels are reduced compared to healthy controls. To date, there are no data on the role and molecular function of irisin in the human placenta or its contribution to pathophysiology. Aberrant trophoblast differentiation is involved in the pathophysiology of preeclampsia. The current study aimed to assess the molecular effects of irisin on trophoblast differentiation and function. First-trimester placental explants were cultured and treated with low (10 nM) and high (50 nM) physiological doses of irisin. Treatment with irisin dose-dependently increased both in vitro placental outgrowth (on Matrigel™) and trophoblast cell-cell fusion. Adenosine monophosphate-activated protein kinase (AMPK) signaling, an important regulator of cellular energy homeostasis that is involved in trophoblast differentiation and pathology, was subsequently investigated. Here, irisin exposure induced placental AMPK activation. To determine the effects of irisin on trophoblast differentiation, two trophoblast-like cell lines, HTR-8/SVneo and BeWo, were treated with irisin and/or a specific AMPK inhibitor (Compound C). Irisin-induced AMPK phosphorylation in HTR-8/SVneo cells. Additionally, as part of the differentiation process, integrin switching from α6 to α1 occurred as well as increased invasiveness. Overall, irisin promoted differentiation in villous and extravillous cell-based models via AMPK pathway activation. These findings provide evidence that exposure to irisin promotes differentiation and improves trophoblast functions in the human placenta that are affected in abnormal placentation.

The Increased lncRNA MIR503HG in Preeclampsia Modulated Trophoblast Cell Proliferation, Invasion, and Migration via Regulating Matrix Metalloproteinases and NF-κB Signaling

Background

Preeclampsia (PE) is a pregnancy-related syndrome characterized by hypertension and proteinuria after the 20^th week of gestation. The long noncoding RNAs (lncRNAs) have been recently discovered for their roles in the pathogenesis of PE. This study is aimed at determining the expression of lncRNA MIR503 host gene (MIR503HG) in PE placental tissues and exploring the molecular mechanism underlying MIR503HG-mediated trophoblast cell proliferation, invasion, and migration.

Methods

The expression level of MIR503HG in placental tissues, HTR-8/SVneo, and JEG3 cells was determined by quantitative real-time PCR; western blot detected the relevant protein expression levels in HTR-8/SVneo and JEG3 cells; flow cytometry determined cell apoptosis and cell cycle of HTR-8/SVneo and JEG3 cells; trophoblast cell proliferation, invasion, and migration of HTR-8/SVneo and JEG3 cells were measured by CCK-8, transwell invasion, and wound healing assays, respectively.

Results

The highly expressed MIR503HG was detected in PE placental tissues compared to normal placental tissues. MIR503HG overexpression suppressed cell proliferation, invasion, and migration of HTR-8/SVneo and JEG3 cells, while knockdown of MIR503HG increased trophoblast cell proliferation, invasion, and migration. Flow cytometry results showed that MIR503HG overexpression induced apoptosis and caused cell cycle arrest at the G₀/G₁ phase, while MIR503HG knockdown had the opposite actions in HTR-8/SVneo and JEG3 cells. Western blot assay results showed that MIR503HG overexpression suppressed the matrix metalloproteinase-2/-9 and the snail protein expression and increased the E-cadherin expression in trophoblast cells. In addition, MIR503HG overexpression suppressed the NF-κB signaling pathway by inhibiting the phosphorylation of IκBα and the nuclear translocation of NF-κB signaling subunit p65. On the other hand, MIR503HG knockdown played an opposite role in these protein expression levels.

Conclusion

Our results showed that MIR503HG inhibited the proliferation, invasion, and migration of HTR-8/SVneo and JEG3 cells, which may be related to the pathogenesis of PE.

Receptor expression by JEG-3 trophoblast cells in the presence of placenta secreted factors

Preeclampsia still remains one of the most severe pregnancy complications and is an actual problem in the obstetrics practice. At present, the joint impact of cytokines and other placenta secreted factors on trophoblast cell functional activity during preeclampsia complicated pregnancy remains unclear. The aim of the study is to estimate the surface receptors expression by trophoblast cells in the presence of placenta secreted factors during physiological pregnancy and at preeclampsia. Trophoblast cells of the JEG-3 line were incubated in the presence of supernatants obtained by cultivation of placentas from women with physiological pregnancy and with preeclampsia. Surface receptors expression by trophoblast cells was estimated by FACS Canto II flow cytometer. It was established that in the third trimester both under normal and pathological conditions, the placenta secreted factors impact on the cytokine receptor expression by trophoblast differs while the trophoblast response capacity to the migration and proliferation stimulating and inhibiting signals remains stable. JEG-3 line cells enhanced the expression of CD186, CD140a, Integrin β6, VE-cadherin, CD29, and CD140a in the case of incubation in the presence of placenta supernatants from the third-trimester pregnancy complicated with preeclampsia compared to incubation in the presence of placenta supernatants form the third trimester of physiological pregnancy.

Upregulation of Slug expression by cyclosporine A contributes to the pathogenesis of gingival overgrowth

BACKGROUND/PURPOSE

Gingival overgrowth occurs as a side effect of systemic medication with immunosuppressant cyclosporine A (CsA). Slug, a master regulator of epithelial-mesenchymal transition, is dramatically upregulated in a variety of fibrotic diseases. The aim of this study is to investigate the role of epithelial-mesenchymal transition marker Slug in the pathogenesis of CsA-induced gingival overgrowth.

METHODS

Clinically healthy gingiva and CsA-induced gingival overgrowth specimens were analyzed by immunohistochemistry. The effect of CsA on normal human gingival fibroblasts (HGFs) was used to elucidate whether Slug expression could be affected by CsA by real-time reverse transcription-polymerase chain reaction and western blot. Cell proliferation in CsA-treated HGFs with Slug lentiviral-mediated shRNAi knockdown was evaluated by tetrazolium bromide reduction assay.

RESULTS

Slug expression was higher in CsA-induced gingival overgrowth specimens than in clinical healthy gingiva (p < 0.05). Slug expression was significantly higher in CsA-induced gingival overgrowth specimens with higher levels of inflammatory infiltrates (p < 0.05). CsA was found to increase Slug transcript and protein expression in HGFs in a dose-dependent manner (p < 0.05). In addition, knockdown of Slug significantly suppressed CsA-induced cell proliferation in HGFs (p < 0.05).

CONCLUSION

Taken together, upregulation of Slug in HGFs stimulated by CsA may play an important role in the pathogenesis of CsA-induced gingival overgrowth.

Human uterus myoma and gene expression profiling: A novel in vitro model for studying secretory leukocyte protease inhibitor-mediated tumor invasion

Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor that diminishes tissue destruction during inflammation. A recent report revealed high levels of SLPI expression in the oral carcinoma cell. In addition, overexpression of SLPI up-regulates metastasis in lung carcinoma cells. On the other hand, matrix metalloproteinases (MMPs) are proteinases that participate in extracellular matrix degradation. SLPI and MMPs are involved as accelerators of the tumor invasion process; however, their exact roles are not fully understood. Understanding the mechanism of tumor invasion requires models that take the effect of microenvironmental factors into account. In one such in vitro model, different carcinoma cells have been shown to invade myoma tissue in highly distinct patterns. We have used this myoma model, as it provides a more natural stroma-like environment, to investigate the role of SLPI in tumor invasion. Our results indicate that the model provides a relevant matrix for tumor invasion studies, and that SLPI is important for the invasion of oral carcinoma Ca9-22 cells in conjunction with MMPs. Furthermore, using bioinformatics analysis, we have identified candidates as key molecules involved in SLPI-mediated tumor invasion.

Epithelial-mesenchymal transition during extravillous trophoblast differentiation

A successful pregnancy depends on the intricate and timely interactions of maternal and fetal cells. Placental extravillous cytotrophoblast invasion involves a cellular transition from an epithelial to mesenchymal phenotype. Villous cytotrophoblasts undergo a partial epithelial to mesenchymal transition (EMT) when differentiating into extravillous cytotrophoblasts and gain the capacity to migrate and invade. This review summarizes our current knowledge regarding known regulators of EMT in the human placenta, including the inducers of EMT, upstream transcription factors that control EMT and the downstream effectors, cell adhesion molecules and their differential expression and functions in pregnancy pathologies, preeclampsia (PE) and fetal growth restriction (FGR). The review also describes the research strategies that were used for the identification of the functional role of EMT targets in vitro. A better understanding of molecular pathways driven by placental EMT and further elucidation of signaling pathways underlying the developmental programs may offer novel strategies of targeted therapy for improving feto-placental growth in placental pathologies including PE and FGR.

Twist1 is involved in trophoblast syncytialization by regulating GCM1

INTRODUCTION

The multinucleated syncytiotrophoblast (STB) is maintained and regenerated by the fusion of underlying cytotrophoblast cells (CTBs) and is responsible for a number of functions in the human placenta. Deficiencies in this structure may result in pregnancy-associated diseases. However, the detailed mechanisms underlying trophoblast syncytialization await further investigation.

METHODS

The location of the transcription factor Twist1 in human placental tissues was identified by immunohistochemistry. The expression of Twist1 and glial cells missing-1 (GCM1) was evaluated by qPCR or western blotting in two cell-fusion models including forskolin-induced fusion of BeWo cells and spontaneous syncytialization of CTBs. The key role of Twist1 in trophoblast differentiation was identified using BeWo cells transfected with Twist1-specific siRNA. We investigated the effect of hypoxia on the expression of Twist1 and GCM1 in primary CTBs cultured with 2% oxygen. The Twist1 binding region in the GCM1 gene was detected by chromatin-immunoprecipitation.

RESULTS

Twist1 was expressed in human placental tissues, and the expression of Twist1 and GCM1 increased in a time-dependent manner during spontaneous syncytialization of primary CTBs and forskolin-induced fusion of BeWo cells. A reduction in Twist1 and GCM1 expression was observed under hypoxic conditions and was accompanied by inhibition of trophoblast syncytialization. Moreover, siRNA-mediated silencing of Twist1 resulted in inhibition of BeWo cells fusion and down-regulation of GCM1 expression. Furthermore, Twist1 was found to bind to the E-box-enriched region in intron 2 of the GCM1 gene during forskolin-induced fusion of BeWo cells.

DISCUSSION

The above results suggest that Twist1 is required during trophoblast syncytialization. Twist1 may promote trophoblast syncytialization by regulating the expression of GCM1.

Glucocorticoid exposure in early placentation induces preeclampsia in rats via interfering trophoblast development

In pregnancy, placenta can be exposed to glucocorticoids (GCs) via several ways, which may disturb placentation and adversely affect pregnancy. Preeclampsia (PE) is thought to be attributed, in part, to impaired trophoblast development. The purpose of the present study was to confirm that GC exposure in early placentation could lead to PE in rats, with the mechanisms involving dysregulated trophoblast development. In the study, pregnant rats were administered with 2.5mg/kg Dex subcutaneously once per day from gestational day 7 to 13. Maternal systolic blood pressure and urinary albumin were increased, while both fetus and placenta were restricted after GC exposure relative to the control group. GC exposure also contributed to placental abnormalities and renal impairment. Moreover, placental oxidative damage was increased along with placental hypoxia-inducible factor 1-alpha (HIF1A) overexpression after GC treatment. Mechanically, GC induced PE in rat partially through inhibiting trophoblast proliferation, migration, invasion and epithelial-mesenchymal transition (EMT), which involved phospho-extracellular signal regulated kinase (p-ERK) downregulation. Furthermore, GC receptor was required for the inhibition of GC on trophoblast proliferation, migration, invasion and EMT in vitro. These findings suggest that GC exposure in early placentation could contribute to PE in pregnant rats, with the mechanisms involving inhibition of trophoblast proliferation, migration, invasion and EMT by GC.

The Efficient Derivation of Trophoblast Cells from Porcine In Vitro Fertilized and Parthenogenetic Blastocysts and Culture with ROCK Inhibitor Y-27632

Trophoblasts (TR) are specialized cells of the placenta and play an important role in embryo implantation. The in vitro culture of trophoblasts provided an important tool to investigate the mechanisms of implantation. In the present study, porcine trophoblast cells were derived from pig in vitro fertilized (IVF) and parthenogenetically activated (PA) blastocysts via culturing in medium supplemented with KnockOut serum replacement (KOSR) and basic fibroblast growth factor (bFGF) on STO feeder layers, and the effect of ROCK (Rho-associated coiled-coil protein kinases) inhibiter Y-27632 on the cell lines culture was tested. 5 PA blastocyst derived cell lines and 2 IVF blastocyst derived cell lines have been cultured more than 20 passages; one PA cell lines reached 110 passages without obvious morphological alteration. The derived trophoblast cells exhibited epithelium-like morphology, rich in lipid droplets, and had obvious defined boundaries with the feeder cells. The cells were histochemically stained positive for alkaline phosphatase. The expression of TR lineage markers, such as CDX2, KRT7, KRT18, TEAD4, ELF5 and HAND1, imprinted genes such as IGF2, PEG1 and PEG10, and telomerase activity related genes TERC and TERF2 were detected by immunofluorescence staining, reverse transcription PCR and quantitative real-time PCR analyses. Both PA and IVF blastocysts derived trophoblast cells possessed the ability to differentiate into mature trophoblast cells in vitro. The addition of Y-27632 improved the growth of both PA and IVF blastocyst derived cell lines and increased the expression of trophoblast genes. This study has provided an alternative highly efficient method to establish trophoblast for research focused on peri-implantation and placenta development in IVF and PA embryos.

STAT5 is Activated by Epidermal Growth Factor and Induces Proliferation and Invasion in Trophoblastic Cells

Epidermal growth factor (EGF) is expressed by decidual and trophoblast cells and influences manifold cellular functions during embryo implantation. Thus far, signaling of EGF via Signal Transducer and Activator of Transcription 5 (STAT5) has been only partially investigated. STAT5 stimulates proliferation and cell cycle progression in several cell types. Its dysregulation is associated with pregnancy. The aim of this study was to investigate STAT5 activation and function mediated by EGF in 2 trophoblastic cell lines, namely, HTR8/SVneo and JAR. Additionally, expression of STAT5B messenger RNA (mRNA) in trophoblast models has been compared to that of primary cells isolated from term placentas. Our results demonstrate the highest STAT5B mRNA expression in isolated trophoblast cells, lower expression in HTR8/SVneo cells, and the significantly lowest in JAR cells. Moreover, EGF-mediated STAT5 activation increases cell proliferation and viability in both cell lines. The STAT5 knockdown results in significant decrease in cell viability induced by EGF. Only in HTR8/SVneo cells, invasion decreases after STAT5 silencing and this effect cannot be rescued by further addition of EGF. These results demonstrate that STAT5 activated by EGF constitutes an important cascade for the regulation of cell proliferation and invasion in trophoblast cells.

Epidermal growth factor-like domain 7 promotes migration and invasion of human trophoblast cells through activation of MAPK, PI3K and NOTCH signaling pathways

Epidermal growth factor-like domain 7 (Egfl7) is a gene that encodes a partially secreted protein and whose expression is largely restricted to the endothelia. We recently reported that EGFL7 is also expressed by trophoblast cells in mouse and human placentas. Here, we investigated the molecular pathways that are regulated by EGFL7 in trophoblast cells. Stable EGFL7 overexpression in a Jeg3 human choriocarcinoma cell line resulted in significantly increased cell migration and invasiveness, while cell proliferation was unaffected. Analysis of mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways showed that EGFL7 promotes Jeg3 cell motility by activating both pathways. We show that EGFL7 activates the epidermal growth factor receptor (EGFR) in Jeg3 cells, resulting in downstream activation of extracellular regulated kinases (ERKs). In addition, we provide evidence that EGFL7-triggered migration of Jeg3 cells involves activation of NOTCH signaling. EGFL7 and NOTCH1 are co-expressed in Jeg3 cells, and blocking of NOTCH activation abrogates enhanced migration of Jeg3 cells overexpressing EGFL7. We also demonstrate that signaling through EGFR and NOTCH converged to mediate EGFL7 effects. Reduction of endogenous EGFL7 expression in Jeg3 cells significantly decreased cell migration. We further confirmed that EGFL7 stimulates cell migration by using primary human first trimester trophoblast (PTB) cells overexpressing EGFL7. In conclusion, our data suggest that in trophoblast cells, EGFL7 regulates cell migration and invasion by activating multiple signaling pathways. Our results provide a possible explanation for the correlation between reduced expression of EGFL7 and inadequate trophoblast invasion observed in placentopathies.

Progesterone Inhibits Leptin-Induced Invasiveness of BeWo Cells

BACKGROUND

This study investigated the roles of progesterone and leptin in placenta invasion, which is closely related to pregnancy prognosis. We examined the effects of leptin and progesterone on the invasion of BeWo cells, a human trophoblastic cell line, and the effect of concurrent treatment.

METHODS

Cells were treated with leptin (0, 5, 50, or 500 ng/mL) or progesterone (0, 2, 20, or 200 µM) and cultured in an invasion assay. Cells treated with 500 ng/mL leptin were also treated with progesterone (0, 2, 20, or 200 µM) in the invasion assay for 48 h. The number of cells that invaded the lower surface was counted in five randomly chosen fields using a light microscope with a 200× objective. The mRNA expression levels of MMP-9, TIMP1, TIMP2, and E-cadherin were detected by semi-quantitative PCR.

RESULTS

Invasion of BeWo cells was promoted by leptin and influenced by both leptin concentration and treatment duration. Invasion was most effective at 500 ng/mL leptin and 48 h culture. Leptin-induced invasiveness was suppressed by progesterone in a dose-dependent manner. Leptin significantly decreased the expression levels of TIMP1 and E-cadherin, whereas progesterone significantly decreased expression of MMP-9 and significantly increased levels of TIMP1, TIMP2, and E-cadherin.

CONCLUSIONS

Leptin promotes invasion of BeWo cells, and progesterone suppresses leptin-induced invasion by regulating the expressions of MMP-9, TIMP1, TIMP2, and E-cadherin. The balance between leptin and progesterone may play an important role in human placenta formation during early pregnancy.

Oncostatin M stimulates cell migration and proliferation by down-regulating E-cadherin in HTR8/SVneo cell line through STAT3 activation

BACKGROUND

During the first trimester of pregnancy, trophoblastic E-cadherin expression is down-regulated, thereby allowing extravillous trophoblasts (EVTs) to acquire the potential for migration and invasiveness. The aim of the present study was to investigate the role of OSM on the migration and proliferation of EVT cell line HTR8/SVneo with regard to its effects on the expression of E-cadherin and STAT3 activation.

METHODS

We investigated the effects of OSM on RNA and protein expression of E-cadherin by real time RT-PCR analyses, western blotting, and indirect immunofluorescence staining in HTR8/SVneo cells, as well as the effects on cell migration and proliferation. The selective signal transducer and activator of transcription (STAT)3 inhibitor, stattic, and STAT3 siRNA were used to investigate STAT3 activation by OSM.

RESULTS

OSM significantly reduced RNA and protein expression of E-cadherin. Indirect immunofluorescence staining of HTR8/SVneo cells also revealed the down-regulation of E-cadherin, compared with the controls. OSM-stimulated cell migration was attenuated by anti-gp130 antibodies. OSM-induced STAT3 phosphorylation, and the down-regulation of E-cadherin by OSM treatment was restored by stattic and STAT3 siRNA. In addition, OSM-stimulated migration and proliferation were significantly suppressed by STAT3 inhibition.

CONCLUSIONS

This study suggests that OSM stimulates the migration and proliferation of EVTs during the first trimester of pregnancy through the down-regulation of E-cadherin. In addition, this study suggests that the effects of OSM on migration and proliferation are related to STAT3 activation, which is important in trophoblast invasiveness.

AP-2α suppresses invasion in BeWo cells by repression of matrix metalloproteinase-2 and -9 and up-regulation of E-cadherin

Preeclampsia complicates 5-10% of pregnancies and is a leading cause of maternal/fetal morbidity and mortality. Although the cause is unknown, the reduced migration/invasion of extravillous trophoblasts is generally regarded as a key feature of preeclampsia genesis. The present study examined the expression of activator protein-2α (AP-2α), tissue inhibitor of metalloproteinase 2 (TIMP-2), matrix metalloproteinase-2 (MMP-2), matrix metalloproteinase-9 (MMP-9), and E-cadherin in severe preeclamptic placentas and normal placentas using real-time PCR and immunohistochemistry. The expression levels of AP-2α, TIMP-2, and E-cadherin were elevated, while MMP-2 and MMP-9 levels were decreased in severe preeclamptic placentas when compared with normal placentas. To explore the underlying molecular mechanisms, BeWo cells were transfected with an AP-2α-expression construct as well as a siRNA against AP-2α. The over-expression of AP-2α decreased the invasive abilities of BeWo cells. AP-2α induction was followed by the induction of TIMP-2 and E-cadherin and a significant reduction of MMP-2 and MMP-9. Whereas in AP-2α-silencing BeWo cells, we observed the decreased expression of TIMP-2 and E-cadherin and the increased expression of MMP-2 and MMP-9. We presume that AP-2α may suppress trophoblast invasion by repression of MMP-2 and MMP-9 and up-regulation of E-cadherin, thus leading to shallow placentation in severe preeclampsia.

CXCL12/CXCR4 axis triggers the activation of EGF receptor and ERK signaling pathway in CsA-induced proliferation of human trophoblast cells

Introduction

Our previous study has demonstrated Cyclosporin A (CsA) promotes the proliferation of human trophoblast cells. Therefore, we further investigate the intracellular signaling pathway involved in the CsA-induced proliferation of human trophoblast cells.

Methods

Enzyme-linked immunosorbent assay (ELISA) was performed to evaluate the regulation of CsA on CXCL12 secretion in human trophoblast cells. Immunofluorescence analysis and western blotting analysis were used to investigate the role of CXCL12/CXCR4 axis in the CsA-induced epidermal growth factor receptor (EGFR) phosphorylation in human trophoblast cells. 5-bromo-2′-deoxyuridine (BrdU) cell proliferation assay was performed to analyze the involvement of EGFR and its downstream extracellular signal-regulated protein kinase (ERK) signaling pathway in the CsA-induced proliferation of human trophoblast cells.

Results

Low concentration of CsA promoted the secretion of CXCL12, and recombinant human CXCL12 promoted the phosphorylation of EGFR in primary human trophoblast cells and choriocarcinoma cell line JEG-3. The inhibition of CXCL12 or CXCR4 by either neutralizing antibodies or small interfering RNA (siRNA) could completely block the CsA-induced EGFR phosphorylation. The CsA-induced proliferation of human trophoblast cells was effectively abrogated by the EGFR inhibitor AG1478 as well as the ERK inhibitor U0126, but not by the PI3K/PKB inhibitor LY294002. CsA promoted the activation of ERK in JEG-3 cells, which was markedly abrogated in the presence of CXCL12 siRNA, or CXCR4 siRNA, or AG1478.

Conclusions

CsA may promote EGFR activation via CXCL12/CXCR4 axis, and EGFR downstream ERK signaling pathway may be involved in the CsA-induced proliferation of human trophoblast cells.

Genistein inhibits placental choriocarcinoma cell line JAR invasion through ERβ/MTA3/Snail/E-cadherin pathway

Genistein, the most abundant phytoestrogen in soybeans, may bind to estrogen receptors and perform anticancer activities. Choriocarcinoma is a malignant, trophoblastic and aggressive cancer of the placenta. Few studies are currently available concerning the effects of genistein on choriocarcinoma. In the present study, we investigated the effect of genistein on the invasive potential of the choriocarcinoma cell line JAR and its underlying mechanism. Our data revealed that genistein inhibited JAR cell invasion in a dose-dependent manner by a matrigel invasion assay. Moreover, genistein was found to have decreased the metastasis-associated gene MTA3 mRNA level, increased the transcriptional suppressor Snail mRNA level and upregulated the protein expression of the cell-cell adhesion molecule E-cadherin by real-time RT-PCR and Western blot analysis, respectively. ERβ siRNA was used to knock down ERβ expression in JAR cells. In the ERβ-knockdown JAR cells, genistein failed to inhibit JAR cell invasion. The effects of genistein on MTA3, Snail and E-cadherin expression were also eradicated following ERβ siRNA transfection. These results demonstrated that genistein triggered the MTA3/Snail/E-cadherin regulatory pathway by binding with ERβ, thereby inhibiting JAR cell invasion. In conclusion, our findings have significant implications for the prevention and therapy of choriocarcinoma.