Adhesion and invasion of three human choriocarcinoma cell lines into human endometrium in a three-dimensional organ culture system

Effect of 3D and 2D cell culture systems on trophoblast extracellular vesicle physico-chemical characteristics and potency

The growing understanding of the role of extracellular vesicles (EVs) in embryo-maternal communication has sparked considerable interest in their therapeutic potential within assisted reproductive technology, particularly in enhancing implantation success. However, the major obstacle remains the large-scale production of EVs, and there is still a gap in understanding how different culture systems affect the characteristics of the EVs. In the current study, trophoblast analogue human chorionic carcinoma cell line was cultivated in both conventional monolayer culture (2D) and as spheroids in suspension culture (3D) and how the cell growth environment affects the physical, biochemical and cellular signalling properties of EVs produced by them was studied. Interestingly, the 3D system was more active in secreting EVs compared to the 2D system, while no significant differences were observed in terms of morphology, size, and classical EV protein marker expression between EVs derived from the two culture systems. There were substantial differences in the proteomic cargo profile and cellular signalling potency of EVs derived from the two culture systems. Notably, 2D EVs were more potent in inducing a cellular response in endometrial epithelial cells (EECs) compared to 3D EVs. Therefore, it is essential to recognize that the biological activity of EVs depends not only on the cell of origin but also on the cellular microenvironment of the parent cell. In conclusion, caution is warranted when selecting an EV production platform, especially for assessing the functional and therapeutic potential of EVs through in vitro studies.

Stiff Extracellular Matrix Promotes Invasive Behaviors of Trophoblast Cells

The effect of extracellular matrix (ECM) stiffness on embryonic trophoblast cells invasion during mammalian embryo implantation remains largely unknown. In this study, we investigated the effects of ECM stiffness on various aspects of human trophoblast cell behaviors during cell-ECM interactions. The mechanical microenvironment of the uterus was simulated by fabricating polyacrylamide (PA) hydrogels with different levels of stiffness. The human choriocarcinoma (JAR) cell lineage was used as the trophoblast model. We found that the spreading area of JAR cells, the formation of focal adhesions, and the polymerization of the F-actin cytoskeleton were all facilitated with increased ECM stiffness. Significantly, JAR cells also exhibited durotactic behavior on ECM with a gradient stiffness. Meanwhile, stiffness of the ECM affects the invasion of multicellular JAR spheroids. These results demonstrated that human trophoblast cells are mechanically sensitive, while the mechanical properties of the uterine microenvironment could play an important role in the implantation process.

Senescent endometrial stromal cells transmit reactive oxygen species to the trophoblast-like cells and impair spreading of blastocyst-like spheroids

Successful implantation requires a fine-tuned dialog between the invading embryo and the maternal endometrium. Recently, we discovered that premature senescence of endometrial stromal cells (EnSC) might mediate improper decidual transformation of endometrial tissue and impair endometrial-blastocyst interaction. Here, we show that senescent EnSC are characterized by elevated intracellular reactive oxygen species (ROS) levels that originate from mitochondrial dysfunction and insufficient antioxidant defense. Decidualization of senescent EnSC is defective and is accompanied by the elevated intracellular and mitochondrial ROS levels. Antioxidant defense during decidualization is significantly less efficient in senescent EnSC compared to healthy ones. Senescent EnSC secrete increased amounts of ROS into the extracellular space. Elevated ROS released by senescent EnSC shift the redox balance and induce DNA damage in the neighboring trophoblast-like cells. In an in vitro implantation model, we observed impaired spreading of blastocyst-like spheroids into a monolayer of decidualizing senescent EnSC, which could be compensated by pretreatment of the senescent cells with the antioxidant, Tempol. Hence, we propose a possible mechanism that might be responsible, at least in part, for the defective embryo implantation realized via ROS transmitting from senescent EnSC to trophoblast cells. Such transmission results in the accumulation of ROS and subsequent DNA damage in trophoblastic cells, which might lead to improper migration and invasion of an embryo. In light of these findings, the application of antioxidants prior to implantation might be a promising strategy to improve implantation efficiency.

Usutu Virus Infects Human Placental Explants and Induces Congenital Defects in Mice

Usutu virus (USUV) is a neurotropic mosquito-borne flavivirus that has dispersed quickly in Europe these past years. This arbovirus mainly follows an enzootic cycle involving mosquitoes and birds, but can also infect other mammals, causing notably sporadic cases in humans. Although it is mainly asymptomatic or responsible for mild clinical symptoms, USUV has been associated with neurological disorders, such as encephalitis and meningoencephalitis, highlighting the potential health threat of this virus. Among the different transmission routes described for other flaviviruses, the capacity for some of them to be transmitted vertically has been demonstrated, notably for Zika virus or West Nile virus, which are closely related to USUV. To evaluate the ability of USUV to replicate in the placenta and gain access to the fetus, we combined the use of several trophoblast model cell lines, ex vivo human placental explant cultures from first and third trimester of pregnancy, and in vivo USUV-infected pregnant mice. Our data demonstrate that human placental cells and tissues are permissive to USUV replication, and suggest that viral transmission can occur in mice during gestation. Hence, our observations suggest that USUV could be efficiently transmitted by the vertical route.

Impact of bisphenol A (BPA) on cells and tissues at the human materno-fetal interface

Bisphenol A (BPA) is an endocrine disruptor extensively used in the production of polycarbonate plastics and epoxy resins and a component of liquid and food containers. It is a hazard in the prenatal period because of its presence in the placenta, fetal membranes, amniotic fluid, maternal and fetal blood and its ability to cross the placenta and reach the fetus. Estimation of the risk of BPA exposure during in utero life is extremely important in order to prevent complications of pregnancy and fetal growth. This review describes in vitro models of the human materno-fetal interface. It also outlines the effects of BPA at doses indicated as "physiological", namely at the concentrations found in the general population, and at "supraphysiological" and "subphysiological" doses, i.e. above and below the physiological range. This work will help clarify the discrepancies observed in studies on the effects of BPA on human reproduction and pregnancy, and it will be useful for the choice of appropriate in vitro models for future studies aimed at identifying the potential impact of BPA on specific functional processes.

BAP1/ASXL complex modulation regulates epithelial-mesenchymal transition during trophoblast differentiation and invasion

Normal function of the placenta depends on the earliest developmental stages when trophoblast cells differentiate and invade into the endometrium to establish the definitive maternal-fetal interface. Previously, we identified the ubiquitously expressed tumour suppressor BRCA1-associated protein 1 (BAP1) as a central factor of a novel molecular node controlling early mouse placentation. However, functional insights into how BAP1 regulates trophoblast biology are still missing. Using CRISPR/Cas9 knockout and overexpression technology in mouse trophoblast stem cells, here we demonstrate that the downregulation of BAP1 protein is essential to trigger epithelial-mesenchymal transition (EMT) during trophoblast differentiation associated with a gain of invasiveness. Moreover, we show that the function of BAP1 in suppressing EMT progression is dependent on the binding of BAP1 to additional sex comb-like (ASXL1/2) proteins to form the polycomb repressive deubiquitinase (PR-DUB) complex. Finally, both endogenous expression patterns and BAP1 overexpression experiments in human trophoblast stem cells suggest that the molecular function of BAP1 in regulating trophoblast differentiation and EMT progression is conserved in mice and humans. Our results reveal that the physiological modulation of BAP1 determines the invasive properties of the trophoblast, delineating a new role of the BAP1 PR-DUB complex in regulating early placentation.

Culture strategy as a modulator of target assessments: Functionality of suspension versus hanging drop-derived choriocarcinoma spheroids as in vitro model of embryo implantation

The choriocarcinoma spheroid model has been amply applied to study the underlying molecular mechanism of implantation. Reproducibility and functionality of spheroid tumor models were addressed precisely. To mimic embryo-endometrium crosstalk, no functional characteristics of spheroids have been provided based on culture strategies. In this study, choriocarcinoma spheroids were provided as suspension culture (SC) or hanging drop culture (HDC). Primary assessments were performed based on morphology, cellular density, and hormonal secretion. Spheroid-endometrial cross talk was assessed as coculture procedures. Further, alkaline phosphatase (ALP) activity and expression of genes involved in attachment, invasion, and inducing migration were quantified. We found HDC spheroids provided a homogenous-shaped aggregate with a high grade of viability, cellular integration, hormonal secretion, and the dominant role of WNTs expression in their microarchitecture. SC spheroids showed a higher level of ALP activity and the expression of integrated genes in modulating attachment, invasion, and migration abilities. Spheroid confrontation assays clearly clarified the superiority of SC spheroids to crosstalk with epithelial and stromal cells of endometrium in addition to motivating an ideal endometrial response. Conclusively, culture strategies by affecting various molecular signaling pathways should be chosen precisely according to specific target assessments. Specifically, SC assumed as an ideal model in spheroid-endometrial cross talk.

In vitro study of the effects of DC electric fields on cell activities and gene expression in human choriocarcinoma cells

Physiological electric fields (EFs), as one of the environmental cues influencing both normal and tumor cells, have profound effects on tumor cell malignancy potential. The cellular responses to EFs by choriocarcinoma cells and their underlying mechanisms are unknown. In this study, the migration/motility, cell cycle progression and proliferation of choriocarcinoma cells in electric field culture showed that choriocarcinoma cells migrated cathodally in an applied EF, and EF stimulation influenced cell cycle progression through G2/M arrest and therefore induced a reduction in cellular proliferation. The transcriptome of choriocarcinoma cells subjected to EF stimulation (150 mV/mm) was analyzed using RNA sequencing (RNA-Seq), and the results were verified by reverse transcription quantitative polymerase chain reaction. A Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that ErbB and HIF-1 signaling pathways that are involved in cell migration/motility, cell cycle progression and proliferation were significantly altered in cells treated with an EF of 150 mV/mm compared with control cells, and in addition, the downstream pathways of these signaling pathways such as AKT and P42/P44 MAPK (ERK1/2) showed primary activation by Western blotting. This study's results suggest that an applied EF is an effective cue in regulating cellular phenotypes of choriocarcinoma cells and that transcriptional analysis contributes to the understanding of the mechanism of EF-guided cell functions.

Marijuana-derived cannabinoids inhibit uterine endometrial stromal cell decidualization and compromise trophoblast-endometrium cross-talk

Marijuana (cannabis) use by pregnant women in the United States is increasing and there is a dire need to understand the beneficial or harmful effects of cannabis during pregnancy. Uterine endometrial stromal cells are fibroblast-like cells that differentiate into secretory cells, a process called decidualization, to create a microenvironment conducive for placenta formation and early embryonic growth. In this study, using model human cell lines, we for the first time demonstrate that Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) inhibit endometrial stromal cell decidualization and have adverse effects on trophoblast-endometrium cross-talk.

A Dynamic Culture Method to Produce Ovarian Cancer Spheroids under Physiologically-Relevant Shear Stress

The transcoelomic metastasis pathway is an alternative to traditional lymphatic/hematogenic metastasis. It is most frequently observed in ovarian cancer, though it has been documented in colon and gastric cancers as well. In transcoelomic metastasis, primary tumor cells are released into the abdominal cavity and form cell aggregates known as spheroids. These spheroids travel through the peritoneal fluid and implant at secondary sites, leading to the formation of new tumor lesions in the peritoneal lining and the organs in the cavity. Models of this process that incorporate the fluid shear stress (FSS) experienced by these spheroids are few, and most have not been fully characterized. Proposed herein is the adaption of a known dynamic cell culture system, the orbital shaker, to create an environment with physiologically-relevant FSS for spheroid formation. Experimental conditions (rotation speed, well size and cell density) were optimized to achieve physiologically-relevant FSS while facilitating the formation of spheroids that are also of a physiologically-relevant size. The FSS improves the roundness and size consistency of spheroids versus equivalent static methods and are even comparable to established high-throughput arrays, while maintaining nearly equivalent viability. This effect was seen in both highly metastatic and modestly metastatic cell lines. The spheroids generated using this technique were fully amenable to functional assays and will allow for better characterization of FSS's effects on metastatic behavior and serve as a drug screening platform. This model can also be built upon in the future by adding more aspects of the peritoneal microenvironment, further enhancing its in vivo relevance.

DNA Methylation Inhibitor 5-Aza-2'-Deoxycytidine Modulates Endometrial Receptivity Through Upregulating HOXA10 Expression

Endometrial receptivity is a critical factor for embryo implantation. A decrease in endometrial homeobox A10 (HOXA10) expression is associated with hypermethylation of its promoter and lower endometrial receptivity in animals and humans. 5-Aza-2'-deoxycytidine (AZA) is a DNA methyltransferase inhibitor. However, whether demethylation of the HOXA10 gene could increase the receptivity of the human endometrium remains unknown. Homeobox A10 promoter methylation was analyzed using bisulfite genomic sequencing polymerase chain reaction. Quantitative real time polymerase chain reaction and Western blotting were used to analyze the expression of HOXA10 and its downstream target genes (integrin subunit β 3 [ITGB3] and insulin growth factor binding protein 1 [IGFBP1]) in Ishikawa cells treated with or without AZA for 24 hours. Their protein expression was analyzed with or without HOXA10 siRNA treatment. The effect of AZA on embryo implantation was examined using a Jeg-3 spheroid-endometrial cell attachment assay. The percentage of methylated CpG islands in the HOXA10 promoter was 72.0% without AZA treatment. However, it was 38% and 35% in the 1 and 10 μM AZA treatment groups, respectively. 5-Aza-2'-deoxycytidine strongly induced the expression of HOXA10, ITGB3, and IGFBP1 messenger RNA and their protein expression. Homeobox A10 knockdown led to decreased expression of HOXA10, ITGB3, and IGFBP1, with or without AZA treatment. The attachment rate of Jeg-3 spheroids increased significantly from 82% (control) to 95% (AZA 1 μM) and 96% (AZA 10 μM) after AZA treatment. 5-Aza-2'-deoxycytidine could upregulate the expression of ITGB3 and IGFBP1 via HOXA10 upregulation, and upregulation of ITGB3 and IGFBP1 plays an important role in endometrial receptivity during implantation. 5-Aza-2'-deoxycytidine may improve endometrial receptivity by upregulating the expression of HOXA10.

Oleic acid stimulation of motility of human extravillous trophoblast cells is mediated by stearoyl-CoA desaturase-1 activity

STUDY QUESTION

Do fatty acids regulate development and motility of human extravillous trophoblast cells (EVTs)?

SUMMARY ANSWER

Oleic acid is a promising lipid molecule that has beneficial effects on motility and development of human EVTs.

WHAT IS KNOWN ALREADY

Fatty acid uptake into trophoblast cells is important for maintaining cellular events during pregnancy, but the molecular mechanisms of action of various fatty acids, including trans fatty acids, saturated fatty acids and monounsaturated fatty acids, in EVT cell lines are not clear.

STUDY DESIGN, SIZE, DURATION

Effects of oleic acid, elaidic acid, palmitic acid and stearic acid on HTR8/SVneo cells were assessed in diverse assays in a dose- and time-dependent manner.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Effects of fatty acids on cell proliferation, migration, invasion and apoptosis (Annexin V expression, propidium iodide staining, TUNEL and invasion assays) of HTR8/SVneo cells were determined. Signal transduction pathways in HTR8/SVneo cells in response to fatty acids were determined by Western blot analyses. Regulation of fatty acids on oxidative conditions in EVTs were determined and validated by measurement of production of cellular reactive oxygen species, intracellular concentrations of free Ca2+and lipid peroxidation assays.

MAIN RESULTS AND THE ROLE OF CHANCE

In present study, we confirmed different effects of oleic acid and elaidic acid on migration, invasion, proliferation and apoptosis of the EVT cell line, HTR8/SVneo. We also investigated stearoyl-CoA desaturase-1 (SCD1) to determine if its activity contributed to oleic acid-induced migration of HTR8/SVneo cells. Next, we analyzed cell signaling molecules mediated by oleic acid and elaidic acid treatment, including MAPK and PI3K/AKT pathways in HTR8/SVneo cells. We further established whether selective inhibition of signaling molecules altered the ability of fatty acids to cause changes in migration and proliferation of HTR8/SVneo cells. Last, we examined the regulatory effects of oleic acid and SCD1 on oxidative stress in HTR8/SVneo cells.

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The lack of in vivo animal studies is a major limitation of this research. Effectiveness of oleic acid to stimulate migration of human EVT cells requires further investigation.

WIDER IMPLICATIONS OF THE FINDINGS

Our results suggest that oleic acid can play an important role in promoting invasion of human EVT cell lines while both trans fatty acids and saturated fatty acids are not conducive to normal placentation. This may have implications for the prevention of pre-eclampsia and intrauterine growth restriction.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by a grant from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (No. HI15C0810) awarded to G.S. and (No. HI17C0929) awarded to W.L. There are no conflicts of interest.

Metabolic Reprogramming and the Recovery of Physiological Functionality in 3D Cultures in Micro-Bioreactors

The recovery of physiological functionality, which is commonly seen in tissue mimetic three-dimensional (3D) cellular aggregates (organoids, spheroids, acini, etc.), has been observed in cells of many origins (primary tissues, embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), and immortal cell lines). This plurality and plasticity suggest that probably several basic principles promote this recovery process. The aim of this study was to identify these basic principles and describe how they are regulated so that they can be taken in consideration when micro-bioreactors are designed. Here, we provide evidence that one of these basic principles is hypoxia, which is a natural consequence of multicellular structures grown in microgravity cultures. Hypoxia drives a partial metabolic reprogramming to aerobic glycolysis and an increased anabolic synthesis. A second principle is the activation of cytoplasmic glutaminolysis for lipogenesis. Glutaminolysis is activated in the presence of hypo- or normo-glycaemic conditions and in turn is geared to the hexosamine pathway. The reducing power needed is produced in the pentose phosphate pathway, a prime function of glucose metabolism. Cytoskeletal reconstruction, histone modification, and the recovery of the physiological phenotype can all be traced to adaptive changes in the underlying cellular metabolism. These changes are coordinated by mTOR/Akt, p53 and non-canonical Wnt signaling pathways, while myc and NF-kB appear to be relatively inactive. Partial metabolic reprogramming to aerobic glycolysis, originally described by Warburg, is independent of the cell’s rate of proliferation, but is interwoven with the cells abilities to execute advanced functionality needed for replicating the tissues physiological performance.

Cancer-Specific Inhibitory Effects of Genetically Engineered Stem Cells Expressing Cytosine Deaminase and Interferon-β Against Choriocarcinoma in Xenografted Metastatic Mouse Models

Cancer treatments using stem cells expressing therapeutic genes have been identified for various types of cancers. In this study, we investigated inhibitory effects of HB1.F3.CD and HB1.F3.CD.IFN-β cells expressing Escherichia coli cytosine deaminase (CD) and human interferon-β (IFN-β) genes in intravenously (i.v.) injected mice with a metastasis model. In this treatment, pro-drug 5-fluorocytosine (5-FC) is converted to cytotoxic drug 5-fluorouracil by hNSCs expressing the CD gene, which inhibits DNA synthesis in cancer cells. Moreover, IFN-β induces apoptosis and reduces the growth of cancer cells. Upon MTT assay, proliferation of choriocarcinoma (JEG-3) cells decreased when co-cultured with hNSCs expressing CD and IFN-β genes. To confirm the cancer-tropic effect of these stem cells, chemoattractant factors (VEGF, CXCR4, and C-kit) secreted from JEG-3 cells were identified by polymerase chain reaction. hNSCs migrate toward JEG-3 cells due to ligand-receptor interactions of these factors. Accordingly, the migration capability of hNSCs toward JEG-3 cells was confirmed using an in vitro Trans-well assay, in vivo subcutaneously (s.c.) injected mice groups (xenograft model), and metastasis model. Intravenously injected hNSCs migrated freely to other organs when compared to s.c. injected hNSCs. Thus, we confirmed the inhibition of lung and ovarian metastasis of choriocarcinoma by i.v. injected HB1.F3.CD or HB1.F3.CD.IFN-β cells in the presence of 5-FC. Treatment of these stem cells also increased the survival rates of mice. In conclusion, this study showed that metastatic cancer was diminished by genetically engineered hNSCs and noncytotoxic drug 5-FC. This is the first report of the therapeutic potential of i.v. injected hNSCs in a metastasis model; therefore, the results indicate that this stem cell therapy can be used as an alternative novel tool to treat metastatic choriocarcinoma.

Development of an in vitro model to study uterine functions and early implantation using rat uterine explants

This study was conducted to develop an in vitro model using rat uterine explants to explore complex uterine functions. Rat uterine explants (1-2 mm) were isolated, cultured and further characterized. Steroid hormone treatment of cultured explants showed that both Muc1 and Pr were significantly up-regulated (P < 0.05) by E2. Areg was significantly up-regulated (P < 0.05) by P4 and Igfbp1 was significantly up-regulated (P < 0.05) by the combination of E2 and P4, although, in rat, Igfbp1 is E2-dependent. In vitro decidualization of cultured explants was induced and two potential markers of decidualization, Prl8a2 and Bmp2, were examined. Real-time quantitative PCR data revealed that both Prl8a2 and Bmp2 were significantly up-regulated (P < 0.05) in MPA- and db-cAMP-treated explants compared to the control group of explants. Then, an individual hatched blastocyst and cultured explant was placed in a 96-well (round-bottom U-shaped) plate. Co-culture results showed that stable attachments were observed after 48 h, where embryos were stably attached to the explants and could not be dislodged after mild shaking and/or pipetting. The rates of attachment of embryos to the explants were increased significantly in the P4-treated group (63.6%) compared to the control group (35.5%), after steroid hormone treatment. The rates of attachment were reduced significantly in the E2-treated group (0.0%), where no stable attachments were observed. Despite the necessity of comprehensive investigation, our results suggest that the cultured rat uterine explants can be a useful in vitro model to study uterine functions and early implantation.

IL‑33 restricts invasion and adhesion of trophoblast cell line JEG3 by downregulation of integrin α4β1 and CD62L

Interleukin-33 (IL-33) promotes migration of cancer cells through downregulating the expression of E-cadherin. Previous studies have demonstrated that IL-33 stimulates the proliferation of trophoblasts. However, the effect of IL-33 on the adhesion and invasion of trophoblasts has not been investigated in detail. In the present study, the expression of IL-33 and its receptor, IL-1 receptor-like 1 (ST2), was examined in villi from women during early pregnancy using immunohistochemistry. ST2 expression on human trophoblast and choriocarcinoma cell lines JAR, BeWo, JEG3 and HTR8 was confirmed by flow cytometry (FCM) assay. The effect of recombinant human IL-33 (rhIL-33) on adhesion, invasion and associated molecules was analyzed by cell adhesion, Matrigel invasion and FCM assays. The current study identified that human trophoblasts expressed IL-33 and ST2. RhIL-33 inhibited trophoblast invasion and adhesion, and decreased adhesion and invasion-associated molecules such as integrin α4β1 and CD62L. Therefore, these results suggest that IL-33 may serve an important role in limiting invasion and implantation of trophoblasts by adhesion and invasion-associated molecules, contributing to the formation of the placenta and maintenance of normal pregnancy during early pregnancy.

Binding of galectin-1 to breast cancer cells MCF7 induces apoptosis and inhibition of proliferation in vitro in a 2D- and 3D- cell culture model

Background

Galectin-1 (gal-1) belongs to the family of β-galactoside-binding proteins which primarily recognizes the Galβ1-4GlcNAc sequences of oligosaccharides associated with several cell surface glycoconjugates. The lectin recognizes correspondent glycoepitopes on human breast cancer cells. Galectin-1 is expressed both in normal and malignant tissues. Lymphatic organs naturally possessing high rates of apoptotic cells, express high levels of Galectin-1. Furthermore galectin-1 can initiate T cell apoptosis. Binding of galectin-1 to trophoblast tumor cells presenting the oncofetal Thomsen-Friedenreich (TF) carbohydrate antigen inhibits tumor cell proliferation. In this study we examined the impact galectin-1 has in vitro on cell proliferation, apoptotic potential and metabolic activity of MCF-7 and T-47D breast cancer cells in dependence to their expression of the Thomsen-Friedenreich (TF) tumor antigen.

Methods

For proliferation and apoptosis assays cells were grown in presence of 10, 30 and 60 μg gal-1/ml medium. Cell proliferation was determined by a BrdU uptake ELISA.

Detection of apoptotic cells was done by M30 cyto death staining, in situ nick translation and by a nucleosome ELISA method. Furthermore we studied the impact galectin-1 has on the metabolic activity of MCF-7 and T-47D cells in a homotypic three-dimensional spheroid cell culture model mimicking a micro tumour environment.

Results

Gal-1 inhibited proliferation of MCF-7 cells (strong expression of the TF epitope) but did not significantly change proliferation of T-47D cells (weak expression of the TF epitope). The incubation of MCF-7 cells with gal-1 raised number of apoptotic cells significantly. Treating the spheroids with 30 μg/ml galectin-1 in addition to standard chemotherapeutic regimes (FEC, TAC) resulted in further suppression of the metabolic activity in MCF-7 cells whereas T-47D cells were not affected.

Conclusions

Our results demonstrate that galectin-1 can inhibit proliferation und metabolic cell activity and induce apoptosis in breast tumor cell lines with high expression levels of the Thomsen-Friedenreich (TF) antigen in monolayer and spheroid cell culture models.

A 3D co-culture microtissue model of the human placenta for nanotoxicity assessment

There is increasing evidence that certain nanoparticles (NPs) can overcome the placental barrier, raising concerns on potential adverse effects on the growing fetus. But even in the absence of placental transfer, NPs may pose a risk to proper fetal development if they interfere with the viability and functionality of the placental tissue. The effects of NPs on the human placenta are not well studied or understood, and predictive in vitro placenta models to achieve mechanistic insights on NP-placenta interactions are essentially lacking. Using the scaffold-free hanging drop technology, we developed a well-organized and highly reproducible 3D co-culture microtissue (MT) model consisting of a core of placental fibroblasts surrounded by a trophoblast cell layer, which resembles the structure of the in vivo placental tissue. We could show that secretion levels of human chorionic gonadotropin (hCG) were significantly higher in 3D than in 2D cell cultures, which indicates an enhanced differentiation of trophoblasts grown on 3D MTs. NP toxicity assessment revealed that cadmium telluride (CdTe) and copper oxide (CuO) NPs but not titanium dioxide (TiO₂) NPs decreased MT viability and reduced the release of hCG. NP acute toxicity was significantly reduced in 3D co-culture MTs compared to 2D monocultures. Taken together, 3D placental MTs provide a new and promising model for the fast generation of tissue-relevant acute NP toxicity data, which are indispensable for the safe development of NPs for industrial, commercial and medical applications.

Spherical cancer models in tumor biology

Three-dimensional (3D) in vitro models have been used in cancer research as an intermediate model between in vitro cancer cell line cultures and in vivo tumor. Spherical cancer models represent major 3D in vitro models that have been described over the past 4 decades. These models have gained popularity in cancer stem cell research using tumorospheres. Thus, it is crucial to define and clarify the different spherical cancer models thus far described. Here, we focus on in vitro multicellular spheres used in cancer research. All these spherelike structures are characterized by their well-rounded shape, the presence of cancer cells, and their capacity to be maintained as free-floating cultures. We propose a rational classification of the four most commonly used spherical cancer models in cancer research based on culture methods for obtaining them and on subsequent differences in sphere biology: the multicellular tumor spheroid model, first described in the early 70s and obtained by culture of cancer cell lines under nonadherent conditions; tumorospheres, a model of cancer stem cell expansion established in a serum-free medium supplemented with growth factors; tissue-derived tumor spheres and organotypic multicellular spheroids, obtained by tumor tissue mechanical dissociation and cutting. In addition, we describe their applications to and interest in cancer research; in particular, we describe their contribution to chemoresistance, radioresistance, tumorigenicity, and invasion and migration studies. Although these models share a common 3D conformation, each displays its own intrinsic properties. Therefore, the most relevant spherical cancer model must be carefully selected, as a function of the study aim and cancer type.

MicroRNA-212 Regulates the Expression of Olfactomedin 1 and C-Terminal Binding Protein 1 in Human Endometrial Epithelial Cells to Enhance Spheroid Attachment In Vitro

Successful embryo implantation requires a synchronized dialogue between a competent blastocyst and the receptive endometrium, which occurs in a limited time period known as the "window of implantation." Recent studies suggested that down-regulation of olfactomedin 1 (OLFM1) in the endometrium and fallopian tube is associated with receptive endometrium and tubal ectopic pregnancy in humans. Interestingly, the human chorionic gonadotropin (hCG) induces miR-212 expression, which modulates OLFM1 and C-terminal binding protein 1 (CTBP1) expressions in mouse granulosa cells. Therefore, we hypothesized that embryo-derived hCG would increase miR-212 expression and down-regulate OLFM1 and CTBP1 expressions to favor embryo attachment onto the female reproductive tract. We found that hCG stimulated the expression of miR-212 and down-regulated OLFM1 but not CTBP1 mRNA in both human endometrial (Ishikawa) and fallopian (OE-E6/E7) epithelial cells. However, hCG suppressed the expression of OLFM1 and CTBP1 proteins in both cell lines. The 3'UTR of both OLFM1 and CTBP1 contained binding sites for miR-212. The miR-212 precursor suppressed luciferase expression, whereas the miR-212 inhibitor stimulated luciferase expression of the wild-type (WT)-OLFM1 and WT-CTBP1 reporter constructs. Furthermore, hCG (25 IU/ml) treatments stimulated trophoblastic (Jeg-3) spheroid (blastocyst surrogate) attachment onto Ishikawa and OE-E6/E7 cells. Transfection of miR-212 precursor increased Jeg-3 spheroid attachment onto Ishikawa cells and decreased OLFM1 and CTBP1 protein expressions, whereas the opposite occurred with miR-212 inhibitor. Taken together, hCG stimulated miR-212, which in turn down-regulated OLFM1 and CTBP1 expression in fallopian and endometrial epithelial cells to favor spheroid attachment.

Altered folate metabolism modifies cell proliferation and progesterone secretion in human placental choriocarcinoma JEG-3 cells

Folate is an essential B vitamin required for de novo purine and thymidylate synthesis, and for the remethylation of homocysteine to form methionine. Folate deficiency has been associated with placenta-related pregnancy complications, as have SNP in genes of the folate-dependent enzymes, methionine synthase (MTR) and methylenetetrahydrofolate dehydrogenase 1 (MTHFD1). We aimed to determine the effect of altered folate metabolism on placental cell proliferation, viability and invasive capacity and on progesterone and human chorionic gonadotropin (hCG) secretion. Human placental choriocarcinoma (JEG-3) cells cultured in low folic acid (FA) (2 nM) demonstrated 13% (P<0.001) and 26% (P<0.001) lower proliferation, 5.5% (P=0.025) and 7.5% (P=0.004) lower invasion capacity, and 5 to 7.5% (P=0.004-0.025) lower viability compared with control (20 nM) or supplemented (100 nM) cells, respectively. FA concentration had no effect on progesterone or hCG secretion. Small interfering RNA (siRNA) knockdown of MTR gene and protein expression resulted in 17.7% (P<0.0001) lower proliferation and 61% (P=0.014) higher progesterone secretion, but had no effect on cell invasion and hCG secretion. siRNA knockdown of MTHFD1 gene expression in the absence of detectable changes in protein expression resulted in 10.3% (P=0.001) lower cell proliferation, but had no effect on cell invasion and progesterone or hCG secretion. Our data indicate that impaired folate metabolism can result in lower trophoblast proliferation, and could alter viability, invasion capacity and progesterone secretion, which may explain in part the observed associations between folate and placenta-related complications.

Uterine and placental KISS1 regulate pregnancy: what we know and the challenges that lie ahead

Hypothalamic KISS1 and its derivatives (kisspeptins) are now well recognized as potent stimulators of GnRH secretion and thereby major regulators of the neuroendocrine-reproductive axis. Recent studies in the mouse strongly suggest that independent of the hypothalamus and pituitary, peripherally derived KISS1 also regulates fertility, and disruption of local KISS1 signaling in the ovary and uterus is sufficient to trigger infertility. With this increasing recognition that peripherally derived KISS1 regulates fertility, the first goal of this review is to critically discuss the data that have led to this conclusion, focusing on uterine- and placental-derived KISS1. Given that a significant amount of this data was generated in animals such as the mouse and rat, a second goal of this review is to identify and discuss the limitations of the animal data in the context of better understanding KISS1 as a regulator of human pregnancy. The growing evidence suggests that in both man and mouse, KISS1 plays an important role in regulating very early pregnancy events such as embryo implantation. However, as pregnancy advances, although it seems that KISS1 continues to play important roles in regulating human pregnancy, it might not do so in the mouse. This surprising functional dichotomy between human females and mice appears also to exist between women and a large number of animal species, including lower primates. These findings are of tremendous significance and will greatly shape how KISS1 will be developed as a therapeutic agent in augmenting the reproductive potential of both women and important livestock species.

Aflatoxin B1 augments the synthesis of corticotropin releasing hormone in JEG-3 placental cells

Aflatoxins pose a major threat to food safety. These toxins are classified as hepatocarcinogens; however, their effect on the other tissues is unclear. During pregnancy, the fetus and placental tissues are especially sensitive to toxin exposure. In the present study aflatoxin B1 was found to induce the mRNA expression of corticotrophin-releasing hormone (CRH) in placental cells. A corresponding increase in CRH peptide in the culture medium was also observed. Since signal transduction pathways have been described previously in the control of CRH transcription, the status of protein kinase Cs (PKCs) and mitogen-activated protein kinases (MAPKs) were determined by Western analysis. In the aflatoxin B1-treated cultures, PKC α/βII/δ and ERK-1/2 were activated. As the PKC inhibitor bisindolylmaleimide I and the ERK inhibitor PD98059 could revert the induced CRH expression, the pathways dictated by PKC and ERK were likely involved in the transcriptional regulation. Electrophoretic mobility shift assay showed that C/EBP could be the ultimate activated transcription factor. Taken together, this study demonstrated that aflatoxin B1 could increase the parturition-related placental hormone in vitro. These findings might have significant implications for public health.

Gestational diabetes mellitus upregulates vitamin D receptor in extravillous trophoblasts and fetoplacental endothelial cells

OBJECTIVE

Gestational diabetes mellitus (GDM) is often accompanied by low maternal vitamin D, that is, calcitriol (1,25[OH]2 vitamin D3), levels. Here, we tested the hypothesis that the placental vitamin D receptor (VDR) is regulated by calcitriol and altered in GDM with distinct changes in different placental cell types. Specifically, we aimed to localize VDR in human term placentas from normal and GDM pregnancies, to quantify its cellular expression and to study in vitro its regulation by its physiological agonist calcitriol.

STUDY DESIGN

Placental tissue slides of 80 patients (40 with GDM/40 controls) were double stained for VDR and human leukocyte antigen G to identify extravillous trophoblasts (EVTs). Staining intensity was semiquantified. Quantitative real time-polymerase chain reaction and Western blotting measured VDR messenger RNA (mRNA) and protein in decidual tissue. The trophoblast cell line BeWo was used to study in vitro VDR regulation by calcitriol (0.01, 0.1, and 1 nmol/mL).

RESULTS

Vitamin D receptor protein and mRNA levels are upregulated (P < .05) in EVT (1.8-fold) as well as in placental endothelium (5.8-fold) of patients with GDM. Expression of VDR is regulated by calcitriol in a bimodal manner: high doses (0.1 and 1 nmol/mL) caused downregulation, whereas the low dose (0.01 nmol/mL) resulted in VDR upregulation.

CONCLUSION

Vitamin D receptor is upregulated in EVT and endothelium of GDM placentas. This could be due to low maternal vitamin D levels in patients with GDM because in vitro low calcitriol doses upregulate VDR in trophoblast cells.

Activation of endocrine-related gene expression in placental choriocarcinoma cell lines following DNA methylation knock-down

Increasingly, placental DNA methylation is assessed as a factor in pregnancy-related complications, yet the transcriptional impact of such findings is not always clear. Using a proliferative in vitro placental model, the effect of DNA methylation loss on gene activation was evaluated at a number of genes selected for being differentially methylated in pre-eclampsia-associated placentae in vivo. We aimed to determine whether reduced DNA methylation at specific loci was associated with transcriptional changes at the corresponding gene, thus providing mechanistic underpinnings for previous clinical findings and to assess the degree of transcriptional response amongst our candidate genes. BeWo and JEG3 choriocarcinoma cells were exposed to 1 μM 5-Aza-2'-deoxycytidine (5-Aza-CdR) or vehicle control for 48 h, and re-plated and cultured for a further 72 h in normal media before cells were harvested for RNA and DNA. Bisulphite pyrosequencing confirmed that DNA methylation was reduced by ∼30-50% points at the selected loci studied in both cell lines. Gene activation, measured by qRT-PCR, was highly variable and transcript specific, indicating differential sensitivity to DNA methylation. Most notably, loss of DNA methylation at the leptin (LEP) promoter corresponded to a 200-fold and 40-fold increase in LEP expression in BeWo and JEG3 cells, respectively (P < 0.01). Transcripts of steroidogenic pathway enzymes CYP11A1 and HSD3B1 were up-regulated ∼40-fold in response to 5-Aza-CdR exposure in BeWo cells (P < 0.01). Other transcripts, including aromatase (CYP19), HSD11B2, inhibin (INHBA) and glucocorticoid receptor (NR3C1) were more moderately, although significantly, affected by loss of associated DNA methylation. These data present a mixed effect of DNA methylation changes at selected loci supporting cautionary interpretation of DNA methylation results in the absence of functional data.

Peroxisome proliferator-activated receptor-gamma (PPARγ) is down regulated in trophoblast cells of gestational diabetes mellitus (GDM) and in trophoblast tumour cells BeWo in vitro after stimulation with PPARγ agonists

AIMS

Peroxisome proliferator-activated receptor-gamma (PPARγ) plays an important role in insulin metabolism, trophoblast differentiation and anti-inflammatory circuits. The aim of this study was to investigate the expression of PPARγ in the placenta of patients with gestational diabetes mellitus (GDM) and the regulation of PPARγ by its agonists in trophoblast tumour cells BeWo in vitro.

METHODS

PPARγ expression in a total of 80 placentas (40 GDM/40 controls) was analysed by immunohistochemistry using the semi-quantitative immunoreactive score. Furthermore, a quantitative reverse transcription-polymerase chain reaction (PCR) was performed to determine the PPARγ mRNA-expression in both groups. We used a fused and a non-fused BeWo cell culture model for the stimulation with arachidonic acid and 15-Deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2). Afterwards PPARγ mRNA-expression was analysed by quantitative real-time PCR (RT-PCR) (TaqMan).

RESULTS

Using immunohistochemistry we identified a decreased expression of PPARγ in the syncytiotrophoblast and the extravillous trophoblast of GDM placentas compared to normal controls. Furthermore, PPARγ mRNA-expression was reduced in GDM placentas. Stimulation of BeWo cells with arachidonic acid and 15d-PGJ2 caused a downregulation of PPARγ expression.

CONCLUSION

As PPARγ is down regulated by arachidonic acid and 15d-PGJ2, the reduced PPARγ expression in GDM placentas may be due to an altered concentration of fatty acid derivates.

Distribution of decidual natural killer cells and macrophages in the neighbourhood of the trophoblast invasion front: a quantitative evaluation

STUDY QUESTION

Do decidual natural killer (dNK) cells and decidual macrophages (dMph) become enriched in the vicinity of the trophoblast invasion front?

SUMMARY ANSWER

Morphometric image analysis and areal cell density calculations, which excluded observer bias, showed an enrichment of decidual leukocytes in the neighbourhood of the trophoblast invasion front.

WHAT IS KNOWN ALREADY

In previous studies, the number of decidual leukocytes was visually counted in medium- or high power fields. These methods, however, cannot reveal the exact spatial relationship between leukocytes and invasive trophoblast cells, and are therefore prone to subjective errors. Thus, a more objective approach is required.

STUDY DESIGN, SIZE, DURATION

Applying a new method of morphometric image analysis, leukocyte populations were studied in human tissue fragments derived from first trimester placentation sites (n = 7) as well as in co-cultures of first trimester decidual tissue with placental villi of the same pregnancy representing an appropriate in vitro model of trophoblast invasion (n = 15).

PARTICIPANTS/MATERIALS, SETTINGS, METHODS

First trimester decidual tissue was obtained from women undergoing elective terminations of pregnancy at 7-10 weeks of gestational age. Tissue sections were double-stained immunohistochemically for markers of dNK cells or dMph on one hand, and for invasive extravillous trophoblast cells on the other. To analyse the distribution of leukocytes, distinct cell compartments as well as cell neighbourhood areas were defined. Finally, relative areal cell densities were calculated and these data were compared with those of an in vitro model of trophoblast invasion as well as with tissue fragments derived from decidua parietalis without trophoblast cells.

MAIN RESULTS AND THE ROLE OF CHANCE

At first trimester placentation sites, a higher density of dNK cells as well as of dMph was found in close proximity to the invasive trophoblast (P ≤ 0.01), compared with the average areal cell density of decidual leukocytes in the tissue with exclusion of the trophoblast. The highest areal cell density of leukocytes was determined up to a distance of 20 μm from the trophoblast cells, whereas in more distant regions it was even lower than average, indicating a migration of these leukocytes towards the trophoblast invasion front. In the three-dimensional co-culture model, however, we found an enrichment of dMph (P ≤ 0.01) but not of dNK cells (P > 0,05) in the neighbourhood of the invasive trophoblast.

LIMITATIONS, REASONS FOR CAUTION

The morphometric image analysis depends on intense immunohistochemical staining that is free of background and cross-reactivity.

WIDER IMPLICATIONS OF THE FINDINGS

The presented method will be useful not only for the investigation of recurrent miscarriage but also in the fields of tumour immunology and inflammation.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the European Commission (Network of Excellence 'The Control of Embryo Implantation (EMBIC)', FP6-512040, lead researcher: P.S.), and by the Franz Lanyar Foundation of the Medical University of Graz, Austria (Grant #347). None of the authors declared a conflict of interests.

Quantifying the biomechanics of conception: L-selectin-mediated blastocyst implantation mechanics with engineered "trophospheres"

An estimated 12% of women in the United States suffer from some form of infertility. In vitro fertilization (IVF) is the most common treatment for infertility encompassing over 99% of all assisted reproductive technologies. However, IVF has a low success rate. Live birth rates using IVF can range from 40% in women younger than 35 years to 4% in women older than 42 years. Costs for a successful IVF outcome can be upward of $61,000. The low success rate of IVF has been attributed to the inability of the blastocyst to implant to the uterus. Blastocyst implantation is initiated by L-selectin expressing cells, trophoblasts, binding to L-selectin ligands, primarily sialyl Lewis X (sLeX), on the uterine surface endometrium. Legal and ethical considerations have limited the research on human subjects and tissues, whereas animal models are costly or do not properly mimic human implantation biochemistry. In this work, we describe a cellular model system for quantifying L-selectin adhesion mechanics. L-selectin expression was confirmed in Jeg-3, JAR, and BeWo cell lines, with only Jeg-3 cells exhibiting surface expression. Jeg-3 cells were cultured into three-dimensional spheres, termed "trophospheres," as a mimic to human blastocysts. Detachment assays using a custom-built parallel plate flow chamber show that trophospheres detach from sLeX functionalized slides with 2.75 × 10(-3) dyn of force and 7.5 × 10(-5) dyn-cm of torque. This work marks the first time a three-dimensional cell model has been utilized for quantifying L-selectin binding mechanics related to blastocyst implantation.

Endometrial receptivity: a revisit to functional genomics studies on human endometrium and creation of HGEx-ERdb

BACKGROUND

Endometrium acquires structural and functional competence for embryo implantation only during the receptive phase of menstrual cycle in fertile women. Sizeable data are available to indicate that this ability is acquired by modulation in the expression of several genes/gene products. However, there exists little consensus on the identity, number of expressed/not-detected genes and their pattern of expression (up or down regulation).

METHODS

Literature search was carried out to retrieve the data on endometrial expression of genes/proteins in various conditions. Data were compiled to generate a comprehensive database, Human Gene Expression Endometrial Receptivity database (HGEx-ERdb). The database was used to identify the Receptivity Associated Genes (RAGs) which display the similar pattern of expression across different investigations. Transcript levels of select RAGs encoding cell adhesion proteins were compared between two human endometrial epithelial cell lines; RL95-2 and HEC-1-A by quantitative real time polymerase chain reaction (q-RT-PCR). Further select RAGs were investigated for their expression in pre-receptive (n = 4) and receptive phase (n = 4) human endometrial tissues by immunohistochemical studies. JAr spheroid attachment assays were carried out to assess the functional significance of two RAGs.

RESULTS

HGEx-ERdb (http://resource.ibab.ac.in/HGEx-ERdb/) helped identification of 179 RAGs, of which 151 genes were consistently expressed and upregulated and 28 consistently not-detected and downregulated in receptive phase as compared to pre-receptive phase. q-RT-PCR confirmed significantly higher (p<0.005) expression of Thrombospondin1 (THBS1), CD36 and Mucin 16 transcripts, in RL95-2 as compared to HEC-1-A. Further, the pretreatment with antibodies against CD36 and COMP led to a reduction in the percentage of JAr spheroids attached to RL95-2. Immunohistochemical studies demonstrated significantly higher (p<0.05) expression of endometrial THBS1, Cartilage Oligomeric Matrix Protein (COMP) and CD36 in the receptive phase as compared to pre-receptive phase human endometrial tissues.

CONCLUSION

HGEx-ERdb is a catalogue of 19,285 genes, reported for their expression in human endometrium. Further 179 genes were identified as the RAGs. Expression analysis of some RAGs validated the utility of approach employed in creation of HGEx-ERdb. Studies aimed towards defining the specific functions of RAGs and their potential networks may yield relevant information about the major 'nodes' which regulate endometrial receptivity.

Human trophoblast cells modulate endometrial cells nuclear factor κB response to flagellin in vitro

Background

Implantation is a complex process that requires a delicate cooperation between the immune and reproductive system. Any interference in the fine balance could result in embryo loss and infertility. We have recently shown that Toll-like receptor 5 activation results in a decrease of trophoblast cells binding to endometrial cells in an in vitro model of human implantation. However, little is known about the downstream signalling leading to the observed failure in implantation and the factors that modulate this immune response.

Methods and Principal Findings

An in vitro model of embryo implantation was used to evaluate the effect of trophoblasts and flagellin on the activation of NF-κB in endometrial cells and whether TLR5-related in vitro implantation failure is signalled through NF-κB. We generated two different NF-κB reporting cell lines by transfecting either an immortalized endometrial epithelial cell line (hTERT-EECs) or a human endometrial carcinoma cell line (Ishikawa 3-H-12) with a plasmid containing the secreted alkaline phosphatase (SEAP) under the control of five NF-κB sites. The presence of trophoblast cells as well as flagellin increased NF-κB activity when compared to controls. The NF-κB activation induced by flagellin was further increased by the addition of trophoblast cells. Moreover, blocking NF-κB signalling with a specific inhibitor (BAY11-7082) was able to restore the binding ability of our trophoblast cell line to the endometrial monolayer.

Conclusions

These are the first results showing a local effect of the trophoblasts on the innate immune response of the endometrial epithelium. Moreover, we show that implantation failure caused by intrauterine infections could be associated with abnormal levels of NF-κB activation. Further studies are needed to evaluate the target genes through which NF-κB activation after TLR5 stimulation lead to failure in implantation and the effect of the embryo on those genes. Understanding these pathways could help in the diagnosis and treatment of implantation failure cases.

Regulation of SIRT1 determines initial step of endometrial receptivity by controlling E-cadherin expression

Sirtuin 1 (SIRT1), originally found as a class III histone deacetylase, is a principal modulator of pathways downstream of calorie restriction, and the activation of SIRT1 ameliorates glucose homeostasis and insulin sensitivity. We examined the role of SIRT1 in the regulation of uterine receptivity using Ishikawa and RL95-2 endometrial carcinoma cell lines. Exogenous expression of SIRT1 significantly enhanced E-cadherin expression, while small interfering RNA-mediated depletion of endogenous SIRT1 resulted in a significant reduction of E-cadherin expression. A SIRT1 activator resveratrol elevated E-cadherin expression in a dose dependent manner, while SIRT1 repressors nicotinamide and sirtinol exhibited a dose dependent reduction of E-cadherin expression. We also showed that both forced expression of SIRT1 and activation of SIRT1 promote E-cadherin-driven reporter gene constructs, and SIRT1 is localized at E-cadherin promoter containing E-box elements in Ishikawa cells. Using an in vitro model of embryo implantation, we demonstrate that exogenous expression of SIRT1 and stimulation of SIRT1 activity resulted in the Ishikawa cell line becoming receptive to JAR cell spheroid attachment. Furthermore, resveratrol enhanced E-cadherin and Glycodelin protein expression at sites of intercellular contact, suggesting an additive role of resveratrol in promoting implantation. The initial step of human reproduction depends on the capacity of an embryo to attach and implant into the endometrial wall, and these results revealed the novel mechanism that activation and increased expression of SIRT1 play an important role in uterine receptivity.

Phosphorylation of JAK2 by serotonin 5-HT (2A) receptor activates both STAT3 and ERK1/2 pathways and increases growth of JEG-3 human placental choriocarcinoma cell

Serotonin 5-HT(2A) receptor activation improves viability, increases DNA synthesis and activates JAK2-STAT3 and MEK1/2-ERK1/2 signalling pathways in JEG-3 human trophoblast choriocarcinoma cells. The goal of this study was to characterize the signal transduction cascade involved in 5-HT(2A) receptor-induced growth of JEG-3 cells. Selective 5-HT(2A) receptor agonist, DOI, induced JEG-3 cell growth was inhibited by the inhibitor of JAK2 (AG490), MEK1/2 (U0126), phospholipase C-β (PLC-β; U73122) and protein kinase C-β (PKC-β; Gö6976)), whereas the selective phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002) had no effect. Specific inhibitors of PLC-β, PKC-β and Ras (farnesylthiosalicylic acid) inhibit activation of ERK1/2, whereas the PKC-ζ inhibitor GF109203X had no effect. Interestingly, inhibition of JAK2 prevented DOI-induced phosphorylation of ERK1/2 whereas inhibition of ERK1/2 pathway had no effect on DOI-induced activation of STAT3. Taken together, our results demonstrate that both the JAK2-STAT3 and PLC-β-PKC-β-Ras-ERK1/2 signalling pathways are involved in the stimulation of JEG-3 cell growth mediated by DOI. Moreover, this study shows that activation of JAK2 by the 5-HT(2A) receptor is essential to activate both STAT3 and ERK1/2 signalling pathways as well as to increase JEG-3 choriocarcinoma cell growth and survival.

Choriocarcinoma cell line Response to Dexamethasone

Choriocarcinoma cell lines JAr and JEG-3 are model systems for the study of transformed trophoblast. Both cell lines were shown to produce galectin-1, expression of which was increased in choriocarcinoma when compared to the normal trophoblast of pregnancy. In this study the effects of synthetic glucocorticoid dexametha-sone were investigated in both JAr and JEG-3 cell lines by the MTT test, cell based ELISA, and the cell adhesion and migration tests. Viable cell number/cell proliferation of JAr cells was significantly increased after treatment with 0.1 and 1 nmol/L of dexamethasone, while proliferation of JEG-3 cells was significantly increased after treatment in the whole concentration range of dexamethasone (0.1-100 nmol/L). Galectin-1 in JAr cells was modulated by dexamethasone, which mildly, but significantly decreased production at low concentrations (0.1 and 1 nmol/L). In JEG-3 cells production of galectin-1 was significantly decreased only after treatment with 100 nmol/L of dexamethasone. Cell adhesion of JEG-3 was significantly increased in the presence of lactose, an inhibitory sugar for gal-1, while dexamethasone induced decrease of JEG-3 cell migration. These findings have shown that dexamet-hasone may affect proliferation, gal-1 production and cell migration, in a cell line specific manner. These data suggest that glucocorticoid treatmentin vivomight have the potential to affect cell functions in choriocarcinoma.

MicroRNA-34a suppresses invasion through downregulation of Notch1 and Jagged1 in cervical carcinoma and choriocarcinoma cells

MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of other genes by transcriptional inhibition or translational repression. miR-34a is a known tumor suppressor gene and inhibits abnormal cell growth. However, its role in other tumorigenic processes is not fully known. This study aimed to investigate the action of miR-34a on cell invasion. We found that miR-34a is expressed at various levels in cervical cancer (HeLa, SiHa, C4I, C33a and CaSki) and trophoblast (BeWo and JAR) cell lines. Transient forced expression of miR-34a did not affect the proliferation of these cell lines. Computational miRNA target prediction suggested that Notch1 and Jagged1 were targets of miR-34a. By using functional assays, miR-34a was demonstrated to bind to the 3' untranslated regions of Notch1 and Jagged1. Forced expression of miR-34a altered the expression of Notch1 and Jagged1 protein as well as Notch signaling as shown by the response of Hairy Enhancer of Split-1 protein to these treatments using western blot analysis. Forced expression of miR-34a suppressed the invasiveness of HeLa and JAR cells. By using gamma-secretase inhibitor (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester) that interfered Notch signaling and RNA interference that knockdown Notch1 expression, we confirmed that downregulation of Notch1 reduced the invasiveness of the cells. Transfection of intracellular domain of Notch nullifies the effect of miR-34a on the invasiveness of the cells. Besides, we identified that miR-34a affected cell invasion by regulating expression of urokinase plasminogen activator through Notch. Our results provide evidence that miR-34a inhibits invasiveness through regulation of the Notch pathway and its downstream matrix degrading enzyme.

Epigenetic regulation of E-cadherin controls endometrial receptivity

Key to the success of human reproduction is the capacity of an embryo to attach and implant into the endometrial wall after which a nutrient supply is established through placentation. Herein, we have examined the potential epigenetic regulation of uterine receptivity by use of the receptive RL95-2 and nonreceptive AN3-CA endometrial epithelial carcinoma cell lines. Using an in vitro model of embryo implantation, we demonstrate that inhibition of DNA methylation by 5'-aza-2'-deoxycytidine (AZA), resulted in the nonreceptive AN3-CA cell line becoming receptive to BeWo cell spheroid attachment. Examination of components of the adherens junction complex revealed that AZA specifically increased the expression of E-cadherin and plakoglobin at the mRNA and protein levels in AN3-CA cells, and E-cadherin protein expression was found to localize to sites of intercellular contact. Forced expression of E-cadherin in AN3-CA cells significantly enhanced receptivity. Small interfering RNA (siRNA)-mediated depletion of the individual DNA methyltransferase (DNMT) molecules did not induce E-cadherin expression in AN3-CA cells; however, concomitant siRNA-mediated depletion of both DNMT3A and DNMT3B induced the expression of E-cadherin. Furthermore, E-cadherin expression was significantly increased after the concomitant siRNA-mediated depletion of DNMT-1, -3A, and -3B in AN3-CA cells. Therefore, we have provided evidence that E-cadherin plays an important role in uterine receptivity and that E-cadherin expression is epigenetically regulated in AN3-CA cells, suppressed by the combined actions of DNMT-1, -3A, and -3B.

Endothelin (ET)-1 and ET-3 promote expression of c-fos and c-jun in human choriocarcinoma via ET(B) receptor-mediated G(i)- and G(q)-pathways and MAP kinase activation

BACKGROUND AND PURPOSE

Endothelins (ETs) and their G protein-coupled receptors exert key physiological functions during normal and aberrant placental development. Trophoblast cells mediate the contact between the embryo and the mother, by establishing a transient organ, the placenta. Choriocarcinoma cells display many of the biochemical and morphological characteristics of in utero invasive trophoblast cells and may therefore be used as a suitable model to study epithelial tumour progression of foetal-derived cells.

EXPERIMENTAL APPROACH

The present study aimed at investigating ET receptor-mediated activation of the mitogen-activated protein kinase (MAPK) pathway in human choriocarcinoma.

KEY RESULTS

Both JAR and Jeg-3 choriocarcinoma cell lines expressed ET receptor subtype B (ET(B)) but not ET(A) receptor transcripts. ET(B) receptor engagement by ET-1 and ET-3 resulted in a similar time- and concentration-dependent phosphorylation of p42/44 MAPK, also known as extracellular regulated kinase 1/2. Using specific pharmacological antagonists/inhibitors, we showed that ET-1/-3-mediated signal transduction by the ET(B) receptor is transmitted via G(i)- and G(q)-dependent pathways through activation of the Src (G(i)) and protein kinase C (G(q)) axis that converge at Ras/Raf, leading to downstream activation of p42/44. On a functional level, ET(B) engagement and subsequent phosphorylation of p42/44 resulted in enhanced transcription of the immediate early response genes c-fos and c-jun, a process commonly assumed to be mediated by the ET(A) receptor, and increased cell growth and relative cell area.

CONCLUSIONS AND IMPLICATIONS

As human choriocarcinoma cells secrete ETs, pharmacological antagonism of ETs and/or ET(B) receptor-mediated signal transduction could represent a likely target therapy for choriocarcinoma.

Binding of galectin-1 (gal-1) to the Thomsen–Friedenreich (TF) antigen on trophoblast cells and inhibition of proliferation of trophoblast tumor cells in vitro by gal-1 or an anti-TF antibody

Galectin-1 (gal-1), a member of the mammalian beta-galactoside-binding proteins, recognizes preferentially Galbeta1-4GlcNAc sequences of several cell surface oligosaccharides. We demonstrate histochemically that the lectin recognizes appropriate glycotopes on the syncytiotrophoblast and extravillous trophoblast layer from second trimester human placenta and on BeWo chorion carcinoma cells. Gal-1 binding to BeWo cells was diminished by the Thomsen-Friedreich (TF)-disaccharide (Galbeta1-3GalNAc-) conjugated to polyacrylamide (TF-PAA). Gal-1 also inhibited BeWo cell proliferation in a concentration-dependent manner. Similar antiproliferative effects were also observed with an anti-TF monoclonal antibody (mAb, A78-G/A7). Therefore, we conclude that ligation of Galbeta1-4GlcNAc and Galbeta1-3GalNAc epitopes on BeWo cells may have regulatory effects on cell proliferation.