Role of IGF2BP3 in trophoblast cell invasion and migration

Extracellular vesicles alter trophoblast function in pregnancies complicated by COVID-19

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) causes placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction and alteration of the placental transcriptome. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized maternal circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiology in vitro . We found that the gestational timing of COVID-19 is a major determinant of circulating EV function and cargo. In vitro trophoblast exposure to EVs isolated from patients with an active infection at the time of delivery, but not EVs isolated from Controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an active infection, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19 and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.

Expression of IMP3 and LIN28A RNA-Binding Proteins in Placentas of Patients with Pre-Eclampsia with and without Severe Features

BACKGROUND

this study aimed to determine the expression of RNA-binding oncofetal proteins IMP3 and LIN28A in extravillous (EVT) and villous trophoblast (VT) cells of placentas from pre-eclamptic (PE) pregnancies to better understand the pathogenesis of PE.

METHODS

placental tissue of 10 patients with PE with severe features, 10 patients with PE without severe features and 20 age-matched healthy pregnancy controls were analyzed by immunohistochemistry, double immunofluorescence and qPCR.

RESULTS

We found a decreased percentage of IMP3-positive EVT cells in PE with and without severe features compared to that of the healthy control (p < 0.001). IMP3 expression was significantly low in VT of PE placentas compared to that of the healthy control (p = 0.002). There was no significant difference in LIN28A expression between groups of PE and the control group. Additionally, we noticed the trend toward downregulation of IMP3 mRNA and LIN28A mRNA in severe PE compared to that of healthy controls.

CONCLUSIONS

We demonstrated that IMP3 expression is decreased in EVT and VT cells of placentas from pregnancies complicated with both PE with and without severe features. However, additional functional investigations are needed to clarify the role of IMP3 as a potential therapeutic target in the management of PE.

Differential expression and clinical significance of IGF2BP3 in peritoneal dialysate of patients with varying duration of peritoneal dialysis

This study aims to investigate the differential expression of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) in the peritoneal dialysate among patients with different durations of peritoneal dialysis and its association with the angiogenic marker vascular* endothelial growth factor (VEGF), the fibronectin (FN), and various clinical indicators. A cohort of 122 peritoneal dialysis patients was categorized into short-term (≤1 year, n = 33), mid-term (>1 and ≤5 years, n = 55), and long-term (>5 years, n = 34) groups based on dialysis duration. We utilized enzyme-linked immunosorbent assay (ELISA) and western blot assays to quantify the levels of IGF2BP3, VEGF, and FN in the dialysate. Our findings showed a progressive increase in IGF2BP3 levels with the duration of PD, with the long-term group exhibiting significantly higher levels than both the short-term and mid-term groups (p < 0.001). A positive correlation between IGF2BP3 and VEGF (r = 0.386, p = 0.013), as well as between IGF2BP3 and FN (r = 0.340, p = 0.030), was observed. IGF2BP3 levels also correlated positively with serum creatinine, calcium, and phosphorus levels. In vitro analysis further confirmed that IGF2BP3 expression is enhanced in human peritoneal mesothelial cells under high-glucose conditions (p < 0.05). The study highlights the potential of IGF2BP3 in PD effluent as a biomarker for monitoring PF progression, with its expression significantly correlated with the duration of PD (Pearson r = 0.897, p < 0.001). In conclusion, our results underscore a correlation between elevated IGF2BP3 levels and PD duration, suggesting the clinical significance of IGF2BP3 as a biomarker for PF progression.

Silencing long noncoding RNA LINC01133 suppresses pancreatic cancer through regulation of microRNA-1299-dependent IGF2BP3

The deregulation of long noncoding RNAs (lncRNAs) holds great potential in the treatment of multiple cancers, including pancreatic cancer (PC). However, the specific molecular mechanisms by which LINC01133 contributes to pancreatic cancer remain unknown. Subsequent to bioinformatics analysis, we predicted and analyzed differentially expressed lncRNAs, microRNAs, and genes in pancreatic cancer. We determined the expression patterns of LINC01133, miR-1299, and insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) in pancreatic cancer cells, and validated their interactions through luciferase reporter and RNA immunoprecipitation assays. We implemented loss-of-function and gain-of-function experiments for LINC01133, miR-1299, and IGF2BP3 to assay their potential effects on pancreatic cancer cell functions. We observed high expression of LINC01133 and IGF2BP3, but low expression of miR-1299, in pancreatic cancer cells. Furthermore, we found that LINC01133 enhances IGF2BP3 through binding with miR-1299. Silencing LINC01133 or IGF2BP3 and/or overexpressing miR-1299 limited pancreatic cancer cell proliferation, invasion, epithelial-mesenchymal transition, and suppressed tumorigenic abilities in mice lacking T cells (nude mice). Overall, our findings identified that silencing LINC01133 downregulates IGF2BP3 by upregulating miR-1299 expression, ultimately leading to the prevention of pancreatic cancer.

GPC3 and PEG10 peptides associated with placental gp96 elicit specific T cell immunity against hepatocellular carcinoma

The placenta and tumors can exhibit a shared expression profile of proto-oncogenes. The basis of placenta-derived heat shock protein gp96, which induces prophylactic and therapeutic T cell responses against cancer including hepatocellular carcinoma (HCC), remains unknown. Here, we identified the associated long peptides from human placental gp96 using matrix-assisted laser desorption/ionization-time-of-flight and mass spectrometry and analyzed the achieved proteins through disease enrichment analysis. We found that placental gp96 binds to numerous peptides derived from 73 proteins that could be enriched in multiple cancer types. Epitope-harboring peptides from glypican 3 (GPC3) and paternally expressed gene 10 (PEG10) were the major antigens mediating anti-HCC T cell immunity. Molecular docking analysis showed that the GPC3- and PEG10-derived peptides, mainly obtained from the cytotrophoblast layer of the mature placenta, bind to the lumenal channel and client-bound domain of the gp96 dimer. Immunization with bone marrow-derived dendritic cells pulsed with recombinant gp96-GPC3 or recombinant gp96-PEG10 peptide complex induced specific T cell responses, and T cell transfusion led to pronounced growth inhibition of HCC tumors in nude mice. We demonstrated that the chaperone gp96 can capture antigenic peptides as an efficient approach for defining tumor rejection oncoantigens in the placenta and provide a basis for developing GPC3 and PEG10 peptide-based vaccines against HCC. This study provides insight into the underlying mechanism of the antitumor response mediated by embryonic antigens from fetal tissues, and this will incite more studies to identify potential tumor rejection antigens from placenta.

Exploring the role of m6A modification in the great obstetrical syndromes

BACKGROUND

N6-methyladenosine (m6A) is one of the predominant RNA epigenetic modifications that modify RNAs reversibly and dynamically by "writers" (methyltransferase), "erasers" (demethylase), and "readers."

OBJECTIVE

This review aimed to provide a comprehensive understanding of the complexity of m6A regulation in the great obstetrical syndromes to understand its pathogenesis and potential therapeutic targets.

METHODS

The terms "placenta or trophoblast" and "m6A or N6-methyladenosine" were searched in PubMed databases (June 2023).

RESULTS

In this review, we discuss the regulatory role of m6A in the great obstetrical syndromes such as preeclampsia (PE), spontaneous abortion (SA), hyperglycemia in pregnancy (HIP) and fetal growth to emphasize the clinical relevance of m6A dysregulation in pregnancy. We also describe mechanisms that potentially involve the participation of m6A methylation, such as proliferation, invasion, migration, apoptosis, autophagy, endoplasmic reticulum stress, macrophage polarization, and inflammation.

CONCLUSION

We summarize the recent research progress on the role of m6A modification in the great obstetrical syndromes and placental function and provide a brief perspective on its prospective applications.

N6-methyladenosine (m6A) Modification in Preeclampsia

Recently, epitranscriptional modification of N6-methyladenosine (m6A) has received growing attention in the research on the pathogenesis of preeclampsia. Advances in m6A sequencing have revealed the molecular mechanism and importance of m6A modification. In addition, epitranscriptional modification of m6A is closely related to the metabolic processes of placental tissues and cells in preeclampsia. This article reviews the composition, mode of action, and bioinformatics analysis of m6A modification-related proteins, and their biological function in the progression of preeclampsia. The relationship between m6A modification and preeclampsia risk factors, such as diabetes, cardiovascular disease, obesity, and psychological stress, is summarized to provide new ideas for studying PE-targeting molecules.

A circular RNA activated by TGFβ promotes tumor metastasis through enhancing IGF2BP3-mediated PDPN mRNA stability

Metastasis is the leading cause of cancer-related death, where TGFβ-induced epithelial-mesenchymal transition (EMT) process confers on cancer cells increased metastatic potential. However, the involvement of circRNAs in this process is still obscure. Here, we identify a TGFβ-induced circRNA called circITGB6 as an indispensable factor during the TGFβ-mediated EMT process. circITGB6 is significantly upregulated in metastatic cancer samples and its higher abundance is closely correlated to worse prognosis of colorectal cancer (CRC) patients. Through gain- and loss-of-function assays, circITGB6 is found to potently promote EMT process and tumor metastasis in various models in vitro and in vivo. Mechanistically, circITGB6 enhances the mRNA stability of PDPN, an EMT-promoting gene, by directly interacting with IGF2BP3. Notably, interfering circITGB6 with PEI-coated specific siRNA effectively represses liver metastasis. Therefore, our study reveals the function of a TGFβ-regulated circRNA in tumor metastasis and suggests that targeting circITGB6 is a promising strategy for cancer therapy.

Multi-omics analysis of N6-methyladenosine reader IGF2BP3 as a promising biomarker in pan-cancer

Background

Insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) has been reported to exhibit an oncogenic effect as an RNA-binding protein (RBP) by promoting tumor cell proliferation, migration and invasion in several tumor types. However, a pan-cancer analysis of IGF2BP3 is not currently available, and the exact roles of IGF2BP3 in prognosis and immunology in cancer patients remain enigmatic. The main aim of this study was to provide visualization of the systemic prognostic landscape of IGF2BP3 in pan-cancer and to uncover the potential relationship between IGF2BP3 expression in the tumor microenvironment and immune infiltration profile.

Methods

Raw data on IGF2BP3 expression were obtained from GTEx, CCLE, TCGA, and HPA data portals. We have investigated the expression patterns, diagnostic and prognostic significance, mutation landscapes, functional analysis, and functional states of IGF2BP3 utilizing multiple databases, including HPA, TISIDB, cBioPortal, GeneMANIA, GESA, and CancerSEA. Moreover, the relationship of IGF2BP3 expression with immune infiltrates, TMB, MSI and immune-related genes was evaluated in pan-cancer. IGF2BP3 with drug sensitivity analysis was performed from the CellMiner database. Furthermore, the expression of IGF2BP3 in different grades of glioma was detected by immunohistochemical staining and western blot.

Results

We found that IGF2BP3 was ubiquitously highly expressed in pan-cancer and significantly correlated with diagnosis, prognosis, TMB, MSI, and drug sensitivity in various types of cancer. Besides, IGF2BP3 was involved in many cancer pathways and varied in different immune and molecular subtypes of cancers. Additionally, IGF2BP3 is critically associated with genetic markers of immunomodulators in various cancers. Finally, we validated that IGF2BP3 protein expression was significantly higher in glioma than in normal tissue, especially in GBM.

Conclusions

IGF2BP3 may be a potential molecular biomarker for diagnosis and prognosis in pan-cancer, especially for glioma. It could become a novel therapeutic target for various cancers.

Deletion of Insulin-like growth factor II mRNA-binding protein 3 participates in the pathogenesis of recurrent spontaneous abortion by inhibiting IL-10 secretion and inducing M1 polarization

Insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3) has been proved to affect trophoblast function and embryonic development, but its role and potential mechanism in recurrent spontaneous abortion (RSA) are not clear. RSA is a complex reproductive disease, causing physical and mental damage to patients. In recent years, many studies have found that immune microenvironment is vital to maintain successful pregnancy in the maternal fetal interface. Therefore, this study aims to explore the role of IGF2BP3 in affecting macrophage polarization and its possible mechanism. In this article, we found that IGF2BP3 expression was decreased in placental villous samples of human and RSA mouse model, and knockdown of IGF2BP3 in HTR8/SVneo cells promotes M1 Mφ polarization. Combining with RNA sequencing analysis, we found that IGF2BP3 may regulate the Mφ polarization by affecting the expression of trophoblast cytokines, especially IL-10 secretion. Further mechanistic studies showed that knockdown of IGF2BP3 decreased expression of IL-10 by activating NF-κB pathway. Moreover, we found that M2 Mφ promote trophoblast invasion not IGF2BP3 dependent. Our study reveals the interaction between trophoblast cells and macrophages at the maternal-fetal interface of RSA patients, and will provide theoretical guidance for its diagnosis and treatment of RSA patients.

The role of insulin-like growth factor 2 mRNA binding proteins in female reproductive pathophysiology

Insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs) family belongs to a highly conserved family of RNA-binding proteins (RBPs) and is responsible for regulating RNA processing including localization, translation and stability. Mammalian IMPs (IMP1-3) take part in development, metabolism and tumorigenesis, where they are believed to play a major role in cell growth, metabolism, migration and invasion. IMPs have been identified that are expressed in ovary, placenta and embryo. The up-to-date evidence suggest that IMPs are involved in folliculogenesis, oocyte maturation, embryogenesis, implantation, and placentation. The dysregulation of IMPs not only contributes to carcinogenesis but also disturbs the female reproduction, and may participate in the pathogenesis of reproductive diseases and obstetric syndromes, such as polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM) and gynecological tumors. In this review, we summarize the role of IMPs in female reproductive pathophysiology, and hope to provide new insights into the identification of potential therapeutic targets.

Advanced Maternal Age-associated SIRT1 Deficiency Compromises Trophoblast Epithelial-Mesenchymal Transition through an Increase in Vimentin Acetylation

Advanced maternal age (AMA) pregnancies are rapidly increasing and are associated with aberrant trophoblast cell function, poor placentation, and unfavorable pregnancy outcomes, presumably due to premature placental senescence. SIRT1 is an NAD⁺ -dependent deacetylase with well-known antiaging effects, but its connection with placental senescence is unreported. In this study, human term placentas and first-trimester villi were collected from AMA and normal pregnancies, and a mouse AMA model was established by cross breeding young and aged male and female C57 mice. SIRT1 expression and activity in HTR8/SVneo cells were genetically or pharmacologically manipulated. Trophoblast-specific Sirt1-knockout (KO) mouse placentas were generated by mating Elf5-Cre and Sirt1^fl/fl mice. Trophoblast cell mobility was assessed with transwell invasion and wound-healing assays. SIRT1-binding proteins in HTR8/SVneo cells and human placental tissue were identified by mass spectrometry. We identified SIRT1 as the only differentially expressed sirtuin between AMA and normal placentas. It is downregulated in AMA placentas early in the placental life cycle and is barely impacted by paternal age. SIRT1 loss upregulates P53 acetylation and P21 expression and impairs trophoblast invasion and migration. Sirt1-KO mouse placentas exhibit senescence markers and morphological disruption, along with decreased fetal weight. In trophoblasts, SIRT1 interacts with vimentin, regulating its acetylation. In conclusion, SIRT1 promotes trophoblast epithelial-mesenchymal transition (EMT) to enhance invasiveness by modulating vimentin acetylation. AMA placentas are associated with premature senescence during placentation due to SIRT1 loss. Therefore, SIRT1 may be an antiaging therapeutic target for improving placental development and perinatal outcomes in AMA pregnancies.

Neuroprotective Effects of Deproteinized Calf Serum in Ischemic Stroke

Deproteinized calf serum (DCS) may have neuroprotective effects after ischemic stroke. The aim of this study is to investigate whether and how the DCS inhibits neuronal injury following cerebral ischemia. Rats were subjected to 2 h transient middle cerebral artery occlusion (MCAO). One dose of 0.125 mg/gbw DCS was given immediately after reperfusion. Neurological deficit and infarct volume at 24 h post-MCAO in DCS-treated rats were lower than those in vehicle-treated rats (p < 0.0005). In cultured neurons model, cell viability was decreased, and apoptosis was increased by oxygen-glucose deprivation/reperfusion (OGD/R) (p < 0.0005). These effects of OGD/R were attenuated by 0.4 μg/μl DCS (p < 0.05) that were validated by CCK8 cell viability assay, phycoerythrin–Annexin V Apoptosis Detection assay, and TUNEL assay. Furthermore, the increase of intracellular ROS level in cultured neurons was suppressed by DCS (p < 0.05). Compared with cells subjected to OGD/R, the expression level of Bax protein decreased, and bcl-2 protein increased after DSC treatment (p < 0.05). Overall, the neuroprotective effects of DCS following cerebral ischemia may in part be due to decreased ROS production and inhibition of apoptosis.

Insertion/deletion variants within the IGF2BP2 gene identified in reported genome-wide selective sweep analysis reveal a correlation with goat litter size

Insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2, also called IMP2) plays an essential role in the development and maturation of germ cells and embryos and is a candidate gene for goat litter size, based on a previous genome-wide selective sweep analysis. In this study, the mRNA expression level of IGF2BP2 was found to be significantly higher in a single-lamb group than in a multi-lamb group. Insertions/deletions (indels) within the goat IGF2BP2 gene, including P4-Ins-13bp and P5-Del-12bp, were verified in 918 Shaanbei White Cashmere (SBWC) female goats. The minor allelic frequencies (MAFs) of P4-Ins-13bp and P5-Del-12bp loci were 0.349 and 0.295, respectively. Analysis using the Chi-square (χ²) test showed that the genotype (χ²=14.479, P=0.006) distribution of P4-Ins-13bp was significantly different between the single-lamb and multi-lamb groups. Correlation analysis demonstrated that P4-Ins-13bp was significantly associated with goat litter size (P=0.022), and individual goats with the homozygous deletion/deletion (DD) genotype produced more litters than other goats. Therefore, considered as a potential molecular marker significantly related to lambing traits, the P4-Ins-13bp mutation of the goat IGF2BP2 gene can be used in goat breeding with practical molecular marker-assisted selection (MAS) to optimize female reproduction and improve economic efficiency in the goat industry.

Fragile X-Related Protein 1 (FXR1) Promotes Trophoblast Migration at Early Pregnancy via Downregulation of GDF-15 Expression

Fragile X-related protein 1 (FXR1) is an RNA-binding protein that can regulate specific mRNA decay in cells. Our previous study showed that FXR1 expression was significantly decreased in trophoblasts from patients with unexplained recurrent spontaneous abortion (RSA); however, the role of FXR1 in trophoblast function during early placenta development has not been fully elucidated. In this study, we found that knockdown of FXR1 using siRNA effectively inhibited the migration of HTR-8 cells and extravillous trophoblast (EVT) outgrowth in an ex vivo extravillous explant culture model. Furthermore, through analysis of a panel of cytokines, we found that the GDF-15 protein was upregulated after knockdown of FXR1 in HTR-8/SVneo cells. This was further confirmed by western blotting and immunofluorescence in HTR-8/SVneo cells and an extravillous explant. Our data also showed that FXR1 expression was downregulated and GDF-15 was upregulated in chorionic villous tissues from RSA patients compared with those from healthy controls (HCs). Further, immunohistochemistry showed a strong expression of GDF-15 in chorionic villous tissue in the RSA group, which was mainly distributed in villous trophoblasts (CTBs) and syncytiotrophoblasts (STBs). Moreover, knockdown of GDF-15 enhanced the migration of HTR-8 cells, while overexpression of GDF-15 using plasmid or treatment with recombinant human GDF-15 protein inhibited trophoblast migration. Importantly, RNA-binding protein immunoprecipitation showed that FXR1 directly bound to the 3'-UTR of GDF-15 mRNA to promote GDF-15 mRNA decay. Together, our data provide new insight into the function of FXR1 in human placenta via regulation of GDF-15 expression in trophoblasts and suggest a possible pathological process involved in RSA.

The biological function of IGF2BPs and their role in tumorigenesis

The insulin-like growth factor-2 mRNA-binding proteins (IGF2BPs) pertain to a highly conservative RNA-binding family that works as a post-transcriptional fine-tuner for target transcripts. Emerging evidence suggests that IGF2BPs regulate RNA processing and metabolism, including stability, translation, and localization, and are involved in various cellular functions and pathophysiologies. In this review, we summarize the roles and molecular mechanisms of IGF2BPs in cancer development and progression. We mainly discuss the functional relevance of IGF2BPs in embryo development, neurogenesis, metabolism, RNA processing, and tumorigenesis. Understanding IGF2BPs role in tumor progression will provide new insight into cancer pathophysiology.

Environmental Pollutant Benzo[a]pyrene Upregulated Long Non-coding RNA HZ07 Inhibits Trophoblast Cell Migration by Inactivating PI3K/AKT/MMP2 Signaling Pathway in Recurrent Pregnancy Loss

Benzo(a)pyrene (BaP) is a ubiquitous environmental endocrine-disrupting chemical that is known to have toxic effects on reproduction. However, the underlying mechanisms describing how BaP and its metabolite benzo[a]pyrene-7, 8-diol-9, 10-epoxide (BPDE) induce recurrent pregnancy loss (RPL) are still largely unclear. In this study, we identified a novel long non-coding RNA (lnc-HZ07, NCBI MT936329) that was upregulated in trophoblast cells after exposure to BPDE, and lnc-HZ07 expression was significantly higher in RPL villous tissues than that in control villous tissues. Knockdown of lnc-HZ07 promoted trophoblast cell migration, whereas overexpression of lnc-HZ07 inhibited trophoblast cell migration. Further study showed that lnc-HZ07 inhibited trophoblast migration by downregulating matrix metalloproteinase 2 (MMP2) expression via dephosphorylation of AKT. These results demonstrated a novel regulatory pathway in which BaP downregulated AKT phosphorylation and inhibited MMP2 expression by upregulating lnc-HZ07, suggesting that lnc-HZ07 could be considered as a potential pathological marker of BaP-induced RPL and therapeutic target for this disease.

Dysfunction of Shh signaling activates autophagy to inhibit trophoblast motility in recurrent miscarriage

In early pregnancy, the placenta anchors the conceptus and supports embryonic development and survival. This study aimed to investigate the underlying functions of Shh signaling in recurrent miscarriage (RM), a serious disorder of pregnancy. In the present study, Shh and Gli2 were mainly observed in cytotrophoblasts (CTBs), Ptch was mainly observed in syncytiotrophoblasts (STBs), and Smo and Gli3 were expressed in both CTBs and STBs. Shh signaling was significantly impaired in human placenta tissue from recurrent miscarriage patients compared to that of gestational age-matched normal controls. VEGF-A and CD31 protein levels were also significantly decreased in recurrent miscarriage patients. Furthermore, inhibition of Shh signaling impaired the motility of JAR cells by regulating the expression of Gli2 and Gli3. Intriguingly, inhibition of Shh signaling also triggered autophagy and autolysosome accumulation. Additionally, knockdown of BECN1 reversed Gant61-induced motility inhibition. In conclusion, our results showed that dysfunction of Shh signaling activated autophagy to inhibit trophoblast motility, which suggests the Shh pathway and autophagy as potential targets for RM therapy.

IGF2BP3 Expression Correlates With Poor Prognosis in Esophageal Squamous Cell Carcinoma

BACKGROUND

Insulin-like growth factor-II mRNA binding protein 3 (IGF2BP3) is an oncofetal RNA-binding protein normally involved in cell growth and migration during the early stages of embryogenesis. However, it is also expressed in various cancers, and the relationship between IGF2BP3 and the clinicopathological features and prognosis of esophageal squamous cell carcinoma patients is not fully understood. Our aim in this study was to determine whether IGF2BP3 expression status correlates with prognosis in patients with advanced thoracic esophageal squamous cell carcinoma.

METHODS

The IGF2BP3 expression statuses of 177 patients treated with esophagectomy without preoperative therapy were evaluated immunohistochemically using tissue microarray analysis. The relationships between IGF2BP3 expression status and clinicopathological features and survival were then assessed using appropriate statistics.

RESULTS

Among 177 esophageal tumors, 122 (68.9%) expressed high levels of IGF2BP3. In patients undergoing surgery alone, IGF2BP3-high expression was significantly associated with a poorer prognosis. By contrast, there were no significant associations between IGF2BP3 expression and clinicopathological features or outcomes in patients treated with surgery plus postoperative adjuvant chemotherapy.

CONCLUSIONS

IGF2BP3 positivity in advanced thoracic esophageal squamous cell carcinoma is associated with adverse clinical outcomes in patients treated with surgery alone.

Trophoblast attachment to the endometrial epithelium elicits compartment-specific transcriptional waves in an in-vitro model

RESEARCH QUESTION

Which are the early compartment-specific transcriptional responses of the trophoblast and the endometrial epithelium throughout early attachment during implantation?

DESIGN

An endometrial epithelium proxy (cell line Ishikawa) was co-cultured with spheroids of a green fluorescent protein (GFP) expressing trophoblast cell line (JEG-3). After 0, 8 and 24 h of co-culture, the compartments were sorted by fluorescence-activated cell sorting; GFP+ (trophoblast), GFP- (epithelium) and non-co-cultured control populations were analysed (in triplicate) by RNA-seq and gene set enrichment analysis (GSEA).

RESULTS

Trophoblast challenge induced a wave of transcriptional changes in the epithelium that resulted in 295 differentially regulated genes involving epithelial to mesenchymal transition (EMT), cell movement, apoptosis, hypoxia, inflammation, allograft rejection, myogenesis and cell signalling at 8 h. Interestingly, many of the enriched pathways were subsequently de-enriched by 24 h (i.e. EMT, cell movement, allograft rejection, myogenesis and cell signalling). In the trophoblast, the co-culture induced more transcriptional changes and regulation of a variety of pathways. A total of 1247 and 481 genes were differentially expressed after 8 h and from 8 to 24 h, respectively. Angiogenesis and hypoxia were over-represented at both stages, while EMT and cell signalling only were at 8 h; from 8 to 24 h, inflammation and oestrogen response were enriched, while proliferation was under-represented.

CONCLUSIONS

Successful attachment produced a series of dynamic changes in gene expression, characterized by an overall early and transient transcriptional up-regulation in the receptive epithelium, in contrast to a more dynamic transcriptional response in the trophoblast.

IGF2BP3 and miR191-5p synergistically increase HCC cell invasiveness by altering ZO-1 expression

Early studies have indicated that insulin-like growth factor II mRNA binding protein 3 (IGF2BP3/IMP3) may affect the progression of hepatocellular carcinoma (HCC); however, the detailed underlying mechanisms, particularly its linkage to tight junction protein-mediated cell invasion, remain unclear. The present study revealed that IGF2BP3 increased HCC cell invasiveness by suppressing zonula occludens-1 (ZO-1) expression, via direct binding to the 3′ untranslated region (3′-UTR). Analysis of the molecular mechanisms demonstrated that IGF2BP3 binds to the overlapping targets of IGF2BP3-RNA cross-linkage and microRNA (miR)191-5p targeting sites, and promotes the formation of an miR191-5p-induced RNA-induced silencing complex. The knockdown of IGF2BP3 or the addition of a miR-191-5p inhibitor decreased cellular invasiveness and increased ZO-1 expression. Analysis of the human HCC database also confirmed the association between IGF2BP3 and HCC progression. Collectively, these preclinical findings suggest that IGF2BP3 increases HCC cell invasiveness by promoting the miR191-5p-induced suppression of ZO-1 signaling. This newly identified signaling effect on small molecule targeting may aid in the development of novel strategies with which to inhibit HCC progression more effectively.

IGF2BP3 (IMP3) expression in angiosarcoma, epithelioid hemangioendothelioma, and benign vascular lesions

Background

Insulin-like growth factor-2 messenger RNA-binding protein 3 (IGF2BP3 or IMP3) is an oncofetal protein that is expressed in various cancer types, and its expression is often associated with poor prognosis. IGF2BP3 expression has not been fully settled in vascular lesions.

Methods

We evaluated the expression of IGF2BP3 in malignant (angiosarcoma and epithelioid hemangioendothelioma [EHE]) and benign (hemangioma, granulation tissue cappilaries, and pyogenic granuloma) vascular lesions using immunohistochemistry. IGF2BP3 expression was scored as negative (0% of endothelial/neoplastic cells), equivocal (1–25%), or positive (> 26%).

Results

Eight of 30 (26.7%) cases of angiosarcoma and two of five (40%) cases of epithelioid hemangioendothelioma were positive for IGF2BP3. In contrast, hemangiomas (10 cases) and granulation tissue capillaries (12 cases) were all negative for IGF2BP3, and some cases of pyogenic granuloma (six of 14 cases) was scored as equivocal. In angiosarcoma, IGF2BP3 expression was independent of age, gender, location, morphological pattern, prognosis, presence of metastatic foci, and PD-L1 expression.

Conclusions

IGF2BP3 is a useful marker to distinguish between malignant and benign vascular lesions.

IGF2BP3 From Physiology to Cancer: Novel Discoveries, Unsolved Issues, and Future Perspectives

RNA network control is a key aspect of proper cellular homeostasis. In this context, RNA-binding proteins (RBPs) play a major role as regulators of the RNA life cycle due to their capability to bind to RNA sequences and precisely direct nuclear export, translation/degradation rates, and the intracellular localization of their target transcripts. Alterations in RBP expression or functions result in aberrant RNA translation and may drive the emergence and progression of several pathological conditions, including cancer. Among the RBPs, insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3) is of particular interest in tumorigenesis and tumor progression. This review highlights the molecular mechanisms underlying the oncogenic functions of IGF2BP3, summarizes the therapeutic potential related to its inhibition and notes the fundamental issues that remain unanswered. To fully exploit IGF2BP3 for tumor diagnosis and therapy, it is crucial to dissect the mechanisms governing IGF2BP3 re-expression and to elucidate the complex interactions between IGF2BP3 and its target mRNAs as normal cells become tumor cells.

IGF2 mRNA binding protein 3 (IMP3) promotes glioma cell migration by enhancing the translation of RELA/p65

The diffusely infiltrative nature of glioblastoma (GBM) makes them highly recurrent. IGF2 mRNA-binding protein 3 (IMP3), a GBM upregulated RNA binding protein, promotes glioma cell migration. An integrative bioinformatics analysis identified p65 (RELA), a subunit of NF-κB heterodimer as a target and an important mediator of IMP3 promoted glioma cell migration. IMP3 increased p65 protein levels without any change in p65 transcript levels, but promoted its polysome association. RIP-PCR demonstrated the binding of IMP3 to p65 transcript. UV crosslinking experiments with in vitro transcribed RNA confirmed the specific and direct binding of IMP3 to sites on p65 3′UTR. Further, IMP3 induced luciferase activity from p65 3′UTR reporter carrying wild type sites but not mutated sites. Exogenous overexpression of p65 from a 3′UTR-less construct rescued the reduced migration of glioma cells in IMP3 silenced condition. In addition, IMP3 silencing inhibited glioma stem-like cell maintenance and migration. The exogenous overexpression of 3′UTR-less p65 significantly alleviated the inhibition of neurosphere formation observed in IMP3 silenced glioma stem-like cells. Further, we show that IMP3 is transcriptionally activated by NF-κB pathway indicating the presence of a positive feedback loop between IMP3 and p65. This study establishes p65 as a novel target of IMP3 in increasing glioma cell migration and underscores the significance of IMP3-p65 feedback loop for therapeutic targeting in GBM.

Dysregulated Expression of RPS4Y1 (Ribosomal Protein S4, Y-Linked 1) Impairs STAT3 (Signal Transducer and Activator of Transcription 3) Signaling to Suppress Trophoblast Cell Migration and Invasion in Preeclampsia

Normal placentation and a successful pregnancy depend on appropriate trophoblast cell migration and invasion. Inadequate trophoblast invasion and impaired spiral artery remodeling may lead to pregnancy-related disorders, such as preeclampsia. RPS4Y1 (ribosomal protein S4, Y-linked 1) is a member of the S4E family of ribosomal proteins. In this study, we found that RPS4Y1 levels were upregulated in placental samples collected from preeclamptic patients, when compared with the normotensive pregnant women. In vitro, inhibition of RPS4Y1 induced trophoblast cell invasion, promoted placental explant outgrowth, and increased STAT3 (signal transducer and activator of transcription 3) phosphorylation along with elevated expression of N-cadherin and vimentin. Conversely, overexpression of RPS4Y1 results in reduced trophoblast cell invasion and decreased STAT3 phosphorylation. In addition, the suppression of RPS4Y1 promotes trophoblast cell invasion, which could be abolished by the STAT3 knockdown. Meanwhile, we observed reductions of STAT3 phosphorylation expression in preeclampsia patients. Collectively, these results demonstrate that the level of RPS4Y1 expression may be associated with preeclampsia by affecting trophoblast cell migration and invasion via the STAT3/epithelial-mesenchymal transition pathway.

miR-181a-5p suppresses invasion and migration of HTR-8/SVneo cells by directly targeting IGF2BP2

Pre-eclampsia is a pregnancy-related disease that may cause maternal, neonatal and fetal morbidity and mortality and exists in 3–5% of pregnancies worldwide. The discovery of dysregulated microRNAs and their roles in placental development has provided a new avenue for elucidating the mechanism involved in this pregnancy-specific disorder. Here, the roles of human miR-181a-5p, a microRNA that is increased in both the plasma and placenta of severe pre-eclamptic patients, in invasion and migration of trophoblasts were investigated. Ectopic-expression of miR-181a-5p impaired the invasion and migration of HTR-8/SVneo cells, whereas miR-181a-5p inhibition had the opposite effects. IGF2BP2, which harbors a highly conserved miR-181a-5p-binding site within its 3ʹ-UTR, was identified to be directly inhibited by miR-181a-5p. Moreover, siRNAs targeting IGF2BP2 imitated the effects of overexpressed miR-181a-5p on HTR-8/SVneo cell invasion and migration, whereas restoring IGF2BP2 expression by overexpressing a plasmid encoding IGF2BP2 partially reversed the studied inhibitory functions of miR-181a-5p. Thus, we demonstrated here that miR-181a-5p suppresses the invasion and migration of cytotrophoblasts, and its inhibitory effects were at least partially mediated by the suppression of IGF2BP2 expression, thus shedding new light on the roles of miR-181a-5p in the pathogenesis of severe pre-eclampsia.

Role of peroxiredoxin2 downregulation in recurrent miscarriage through regulation of trophoblast proliferation and apoptosis

Peroxiredoxin (Prdx) 2 is an antioxidant protein that utilizes its redox-sensitive cysteine groups to reduce hydrogen peroxide molecules and protect cells against oxidative damage from reactive oxygen species (ROS). However, its function in trophoblasts at the maternal-fetal interface has not been clarified yet. In this study, significantly lower Prdx2 expression was found in the first-trimester villous cytotrophoblasts of patients with recurrent miscarriage (RM) than in cytotrophoblasts from healthy controls. Further, Prdx2 knockdown inhibited proliferation and increased apoptosis of trophoblast cells. The reason for this may be an increase in the level of cellular ROS after knockdown of Prdx2, which may subsequently lead to an increase in the expression of phosphorylated p53 (p-p53) and p38-MAPK/p21. Prdx2 knockdown also impaired the fusion of BeWo cells induced by forskolin. Bioinformatics analysis identified a c-Myc-binding site in the Prdx2 promoter region, and chromatin immunoprecipitation verified that c-Myc directly bound to a site in this locus. Suppression and overexpression of c-Myc resulted in reduction and increase of Prdx2 expression respectively. Furthermore, we demonstrated that c-Myc was downregulated in the first-trimester cytotrophoblasts of patients with RM, and its downregulation is also related with inhibited cell proliferation, increased apoptosis, as well as upregulated p21 expression and p-p53/p53 ratio. Our findings indicate that Prdx2 might have an important role in the regulation of trophoblast proliferation and apoptosis during early pregnancy, and that its expression is mediated by c-Myc. Thus, these two proteins may be involved in the pathogenesis of RM and may represent potential therapeutic targets.

Prognostic value of high IMP3 expression in solid tumors: a meta-analysis

BACKGROUND

Accumulated studies have investigated the prognostic role of insulin-like growth factor II mRNA-binding protein 3 (IMP3) in various cancers, but inconsistent and controversial results were obtained. Therefore, we performed a systematic review and meta-analysis to investigate the potential value of IMP3 in the prognostic prediction of human solid tumors.

MATERIALS AND METHODS

A systematic literature search in the electronic databases PubMed, Embase, Web of Science, and Cochrane library (updated to April 2016) was conducted to identify eligible studies. Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) for survival outcomes were calculated and gathered using STATA 12.0 software.

RESULTS

A total of 53 studies containing 8,937 patients with solid tumors were included in this meta-analysis. High IMP3 expression was significantly associated with worse overall survival (OS) of solid tumors (HR =2.08, 95% CI: 1.80-2.42, P<0.001). Similar results were observed in cancer-specific survival (CSS), disease-free survival (DFS), recurrence-free survival (RFS), progression-free survival (PFS), and metastasis-free survival (MFS). Further subgroup analysis stratified by tumor type showed that elevated IMP3 expression was associated with poor OS in renal cell carcinoma (RCC), lung cancer, oral cancer, urothelial carcinoma, hepatocellular carcinoma (HCC), colorectal cancer, pancreatic cancer, gastric cancer, and intrahepatic cholangiocarcinoma (ICC).

CONCLUSION

The current evidence suggests that high IMP3 expression is associated with poor prognosis in most solid tumors. IMP3 is a potential valuable prognostic factor and might serve as a promising biomarker to guide clinical decisions in human solid tumors.

The oncofetal protein IMP3 is an indicator of early recurrence and poor outcome in mucoepidermoid carcinoma of salivary glands

OBJECTIVE

Mucoepidermoid carcinoma (MEC) is the most common primary malignancy of the salivary glands. Insulin-like growth factor-II mRNA-binding protein-3 (IMP3) is an important prognostic factor in some cancers and a tool that differentiates between benign and malignant pancreatic lesions. This study aimed to identify a relationship between the expression of IMP3 and the outcome of salivary gland MEC, as well as to differentiate MEC from pleomorphic adenoma (PA).

METHODS

Tissue specimens from 70 cases of salivary gland MEC, 40 cases of PA, and 10 cases with normal salivary gland were examined immunohistochemically for IMP3. The association among the expression of IMP3, clinicopathological characteristics and patient's survival was assessed.

RESULTS

IMP3 was present in 51.4% of MEC but absent in PA and normal salivary gland tissues. IMP3 expression was associated with age > 60 years, submandibular gland tumors, tumor size > 4 cm, high-grade tumors, lymph node metastasis, involvement of surgical margins, perineural invasion, distant metastasis, advanced TNM stage, tumor relapse, and death ( P<0.05). Increased expression of IMP3, tumors of the submandibular gland, and lymph node metastasis were independent prognostic factors of -free survival (DFS). In addition, IMP3 was a strong predictor of overall survival (OS) together with distant metastasis and intermediate and high-grade tumors.

CONCLUSIONS

IMP3 expression is highly important in evaluating the outcome of MEC. IMP3 can be used to differentiate MEC from PA of salivary glands.

E-Cadherin, CD44v6, and Insulin-Like Growth Factor-II mRNA-Binding Protein 3 Expressions in Different Stages of Hydatidiform Moles

E-cadherin, CD44v6, and IMP3 expression in partial, complete, and invasive hydatidiform moles (HMs) was evaluated. High E-cadherin expression with low CD44v6 expression was observed in partial, complete, and invasive HMs, as well as in normal placental tissues; and there was no significant difference in E-cadherin and CD44v6 expression among the four groups. However, IMP3 expression was gradually decreased in the order of normal placental tissues, partial HMs, complete HMs, and invasive HMs; wherein, invasive HMs had the lowest level. Low IMP3 expression may serve as a prognostic biomarker for HMs, and IMP3 may play a certain role in HMs progression.

The YY1/MMP2 axis promotes trophoblast invasion at the maternal-fetal interface

YY1 is a sequence-specific DNA-binding transcription factor that has many important biological roles. However, its function in trophoblasts at the maternal-fetal interface remains to be elucidated. In this study, we used an mRNA microarray and reverse transcription qPCR and compared the YY1 mRNA expression level in trophoblasts between patients with recurrent miscarriage (RM) and healthy control subjects. Our results revealed that YY1 mRNA expression was significantly lower in the trophoblasts of the RM group compared with the healthy control group. Furthermore, immunofluorescence and immunohistochemical data showed that YY1 was highly expressed in human placental villi during early pregnancy, especially in cytotrophoblast cells and invasive extravillous trophoblasts, and it was expressed at a much lower level in the placental villi of term pregnancy. YY1 overexpression enhanced, and knockdown repressed, the invasion and proliferation of trophoblasts. Antibody array screening revealed that YY1 significantly promoted MMP2 expression in trophoblasts. Bioinformatics analysis identified three YY1-binding sites in the MMP2 promoter region, and chromatin immunoprecipitation analysis verified that YY1 binds directly to its promoter region. Importantly, inhibition of YY1 by siRNA clearly decreased trophoblast invasion in an ex vivo explant culture model. Overall, our findings revealed a new regulatory pathway of YY1/MMP2 in trophoblast cell invasion during early pregnancy and indicated that YY1 may be involved in the pathogenesis of RM.

The RNA binding protein IMP3 facilitates tumor immune escape by downregulating the stress-induced ligands ULPB2 and MICB

Expression of the stress-induced ligands MICA, MICB and ULBP 1–6 are up-regulated as a cellular response to DNA damage, excessive proliferation or viral infection; thereby, they enable recognition and annihilation by immune cells that express the powerful activating receptor NKG2D. This receptor is present not exclusively, but primarily on NK cells. Knowledge about the regulatory mechanisms controlling ULBP expression is still vague. In this study, we report a direct interaction of the oncogenic RNA binding protein (RBP) IMP3 with ULBP2 mRNA, leading to ULBP2 transcript destabilization and reduced ULBP2 surface expression in several human cell lines. We also discovered that IMP3 indirectly targets MICB with a mechanism functionally distinct from that of ULBP2. Importantly, IMP3-mediated regulation of stress-ligands leads to impaired NK cell recognition of transformed cells. Our findings shed new light on the regulation of NKG2D ligands and on the mechanism of action of a powerful oncogenic RBP, IMP3.

DOI:http://dx.doi.org/10.7554/eLife.13426.001

Tumor cells differ from healthy cells in many aspects. Importantly, tumor cells have the ability to divide and grow much faster than normal cells. To protect ourselves from full-grown cancers, our bodies have developed a surveillance system: when a tumor cell starts to divide without restraint, “stress-induced” proteins start to appear on its surface. These proteins help the immune system recognize abnormal or damaged cells, allowing the immune cells to eliminate the defective cells.

Despite this system of protection, a tumor cell sometimes manages to avoid having stress-induced proteins placed on its surface, allowing it to remain undetected by the immune system. By studying several different types of human cancer cells, Schmiedel et al. found that a protein called IMP3 is present in cancer cells but not in healthy cells. Further investigation revealed that IMP3 prevents the production of some stress-induced proteins and stops them moving to the cell surface.

Schmiedel et al. also show that the presence of the IMP3 protein in cancer cells causes nearby immune cells to become much less active. This suggests that developing drugs that block the activity of IMP3 could help the immune system to fight back and destroy cancer cells.

DOI:http://dx.doi.org/10.7554/eLife.13426.002

Genome-wide methylation analysis of retrocopy-associated CpG islands and their genomic environment

Gene duplication by retrotransposition, i.e., the reverse transcription of an mRNA and integration of the cDNA into the genome, is an important mechanism in evolution. Based on whole-genome bisulfite sequencing of monocyte DNA, we have investigated the methylation state of all CpG islands (CGIs) associated with a retrocopy (n = 1,319), their genomic environment, as well as the CGIs associated with the ancestral genes. Approximately 10% of retrocopies are associated with a CGI. Whereas almost all CGIs of the human genome are unmethylated, 68% of the CGIs associated with a retrocopy are methylated. In retrocopies resulting from multiple retrotranspositions of the same ancestral gene, the methylation state of the CGI often differs. There is a strong positive correlation between the methylation state of the CGI/retrocopy and their genomic environment, suggesting that the methylation state of the integration site determined the methylation state of the CGI/retrocopy, or that methylation of the retrocopy by a host defense mechanism has spread into the adjacent regions. Only a minor fraction of CGI/retrocopies (n = 195) has intermediate methylation levels. Among these, the previously reported CGI/retrocopy in intron 2 of the RB1 gene (PPP1R26P1) as well as the CGI associated with the retrocopy RPS2P32 identified in this study carry a maternal methylation imprint. In conclusion, these findings shed light on the evolutionary dynamics and constraints of DNA methylation.

Insulin-Like Growth Factor II mRNA-Binding Protein 3 (IMP3) as a Useful Immunohistochemical Marker for the Diagnosis of Adenocarcinoma of Small Intestine

The biological characteristics and roles of insulin-like growth factor II mRNA-binding protein 3 protein (IMP3) expression in small-intestinal adenocarcinoma were investigated. The value of IMP3 immunostaining in the diagnosis of small-intestinal epithelial lesions was also evaluated. Immunohistochemical expression of IMP3 in normal small-intestinal mucosa adjacent to adenoma and adenocarcinoma lesions, and inflamed duodenal and ileal mucosa was analyzed. Samples assessed were: duodenal ulcer (n=6), Crohn’s disease (n=5), low-grade small-intestinal adenoma (n=10), high-grade small-intestinal adenoma (n=13), small-intestinal adenocarcinoma (n=23), lymph node metastases (LNM; n=7), and preoperative biopsies of small-intestinal adenocarcinoma (n=6). Immunohistochemical expression of Ki-67 and p53 was also analyzed in adenoma and adenocarcinoma samples. IMP3 was not expressed in normal epithelium, but weakly expressed in reparative epithelium. Meanwhile, increased IMP3 expression was associated with a higher degree of dysplasia in adenomas, higher T classification, LNM, Ki-67 positivity, histological differentiation, and lower 5-year disease-free survival, but not p53 expression in adenocarcinoma. IMP3 expression appears to be a late event in the small-intestinal carcinogenesis. Assessing the IMP3 staining pattern can be useful in the diagnosis of small-intestinal epithelial lesions when used in conjunction with other histological criteria.

Comprehensive functional characterization of cancer-testis antigens defines obligate participation in multiple hallmarks of cancer

Tumours frequently activate genes whose expression is otherwise biased to the testis, collectively known as cancer–testis antigens (CTAs). The extent to which CTA expression represents epiphenomena or confers tumorigenic traits is unknown. In this study, to address this, we implemented a multidimensional functional genomics approach that incorporates 7 different phenotypic assays in 11 distinct disease settings. We identify 26 CTAs that are essential for tumor cell viability and/or are pathological drivers of HIF, WNT or TGFβ signalling. In particular, we discover that Foetal and Adult Testis Expressed 1 (FATE1) is a key survival factor in multiple oncogenic backgrounds. FATE1 prevents the accumulation of the stress-sensing BH3-only protein, BCL-2-Interacting Killer (BIK), thereby permitting viability in the presence of toxic stimuli. Furthermore, ZNF165 promotes TGFβ signalling by directly suppressing the expression of negative feedback regulatory pathways. This action is essential for the survival of triple negative breast cancer cells in vitro and in vivo. Thus, CTAs make significant direct contributions to tumour biology.

Proteins usually expressed solely in the testes are often found over-expressed in cancer and are termed cancer testis antigens. Here, the authors use a comprehensive screening strategy to identify 26 cancer-testis antigens that promote tumorigenic behaviour.

New insights into the function of Cullin 3 in trophoblast invasion and migration

Cullin 3 (CUL3), a scaffold protein, assembles a large number of ubiquitin ligase complexes, similar to Skp1-Cullin 1-F-box protein complex. Several genetic models have shown that CUL3 is crucial for early embryonic development. Nevertheless, the role of CUL3 in human trophoblast function remains unclear. In this study, immunostaining revealed that CUL3 was strongly expressed in the villous cytotrophoblasts, the trophoblast column, and the invasive extravillous trophoblasts. Silencing CUL3 significantly inhibited the outgrowth of villous explant ex vivo and decreased invasion and migration of trophoblast HTR8/SVneo cells. Furthermore, CUL3 siRNA decreased pro-MMP9 activity and increased the levels of TIMP1 and 2. We also found that the level of CUL3 in the placental villi from pre-eclamptic patients was significantly lower as compared to that from their gestational age-matched controls. Moreover, in the lentiviral-mediated placenta-specific CUL3 knockdown mice, lack of CUL3 resulted in less invasive trophoblast cells in the maternal decidua. Taken together, these results suggest an essential role for CUL3 in the invasion and migration of trophoblast cells, and dysregulation of its expression may be associated with the onset of pre-eclampsia.

Hedgehog signaling through GLI1 and GLI2 is required for epithelial-mesenchymal transition in human trophoblasts

BACKGROUND

Epithelial to mesenchymal transition (EMT) is critical for human placental development, trophoblastic differentiation, and pregnancy-associated diseases. Here, we investigated the effects of hedgehog (HH) signaling on EMT in human trophoblasts, and further explored the underlying mechanism.

METHODS

Human primary cytotrophoblasts and trophoblast-like JEG-3 cells were used as in vitro models. Quantitative real-time RT-PCR and Western blot analysis were performed to examine mRNA and protein levels, respectively. Lentiviruses expressing short hairpin RNA were used to knock down the target genes. Reporter assays and chromatin immunoprecipitation were performed to determine the transactivity. Cell migration, invasion and colony formation were accessed by wound healing, Matrigel-coated transwell, and colony formation assays, respectively.

RESULTS

Activation of HH signaling induced the transdifferentiation of cytotrophoblasts and trophoblast-like JEG-3 cells from epithelial to mesenchymal phenotypes, exhibiting the decreases in E-Cadherin expression as well as the increases in vimentin expression, invasion, migration and colony formation. Knockdown of GLI1 and GLI2 but not GLI3 attenuated HH-induced transdifferentiation, whereas GLI1 was responsible for the expression of HH-induced key EMT regulators including Snail1, Slug, and Twist, and both GLI1 and GLI2 acted directly as transcriptional repressor of CDH1 gene encoding E-Cadherin.

CONCLUSION

HH through GLI1 and GLI2 acts as critical signals in supporting the physiological function of mature placenta.

GENERAL SIGNIFICANCE

HH signaling through GLI1 and GLI2 could be required for the maintenance of human pregnancy.

LIF upregulates poFUT1 expression and promotes trophoblast cell migration and invasion at the fetal-maternal interface

Trophoblast cell migration and invasion are crucial for the establishment of a successful pregnancy. Protein O-fucosyltransferases, such as poFUT1 and poFUT2, catalyze the O-fucosylation of proteins and have important roles in embryonic development. Leukemia inhibitory factor (LIF) is a critical cytokine in the regulation of embryonic development and implantation. However, the exact roles of poFUTs in embryo migration and invasion and the effects of LIF on the expression of poFUTs have not been studied in detail. In the current study, we showed that poFUT1 and LIF were highly expressed in human trophoblast cells and in the serum of women during the first trimester of a normal pregnancy. However, in patients with threatened abortion, poFUT1 and LIF levels were found to be reduced. There were no significant differences in the expression levels of poFUT2 between the two groups. The migration and invasion potential of trophoblasts in an explant culture and in an in vitro implantation model was decreased or increased upon altering poFUT1 expression levels by siRNA or cDNA transfection. Our results also revealed that LIF upregulated the expression of poFUT1. The upregulation of poFUT1 by LIF promoted trophoblast cell migration and invasion at the fetal–maternal interface by activating the PI3K/Akt signaling pathway. Taken together, these study findings suggest that poFUT1 may be used as a marker of embryo implantation.

The role of the oncofetal IGF2 mRNA-binding protein 3 (IGF2BP3) in cancer

The post-transcriptional control of gene expression mediated by RNA-binding proteins (RBPs), long non-coding RNAs (lncRNAs) as well as miRNAs is essential to determine tumor cell fate and thus is a major determinant in cancerogenesis. The IGF2 mRNA binding protein family (IGF2BPs) comprises three RBPs. Two members of the family, IGF2BP1 and IGF2BP3, are bona fide oncofetal proteins, which are de novo synthesized in various human cancers. In vitro studies revealed that IGF2BPs serve as post-transcriptional fine-tuners modulating the expression of genes implicated in the control of tumor cell proliferation, survival, chemo-resistance and metastasis. Consistently, the expression of both IGF2BP family members was reported to correlate with an overall poor prognosis and metastasis in various human cancers. Due to the fact that most reports used a pan-IGF2BP antibody for studying IGF2BP expression in cancer, paralogue-specific functions can barely be evaluated at present. Nonetheless, the accordance of IGF2BPs' role in promoting an aggressive phenotype of tumor-derived cells in vitro and their upregulated expression in aggressive malignancies provides strong evidence that IGF2BPs are powerful post-transcriptional oncogenes enhancing tumor growth, drug-resistance and metastasis. This suggests IGF2BPs as powerful biomarkers and candidate targets for cancer therapy.