Meta-Analysis of EMT Datasets Reveals Different Types of EMT

Differentiation stage-specific expression of transcriptional regulators for epithelial mesenchymal transition in dentate granule progenitors

During the development of the mouse dentate gyrus (DG), granule neuronal progenitors (GNPs) arise from glial fibrillary acidic protein (GFAP)-expressing neural stem cells in the dentate notch. However, the transcriptional regulators that control their stepwise differentiation remain poorly defined. Since neurogenesis involves epithelial-to-mesenchymal transition (EMT)-like processes, we investigated the spatio-temporal expression profiles of the EMT transcription factors Zeb1, Scratch2 (Scrt2) and Nkx6-2 in relation to known GNP markers. Our results show that Zeb1 and Scrt2 exhibit sequential, but partially overlapping expression across embryonic and postnatal stages of GNP differentiation. Zeb1 is highly enriched in gfap-GFP+/Sox2+ neural stem/progenitor pools and subsets of Tbr2+/Prox1+/NeuroD+ intermediate GNPs, whereas Scrt2 predominates in Tbr2+/Prox1+/NeuroD+ GNPs. Strikingly, the neuronal EMT regulator Nkx6-2 shows selective expression in postnatal Tbr2+/Prox1+ GNPs, but it is excluded from embryonic counterparts. This temporally coordinated yet distinct expression of Zeb1, Scrt2 and Nkx6-2 reveals discrete transcriptional programs orchestrating GNP differentiation and neurogenic progression at embryonic versus postnatal stages of DG neurogenesis.

Two-Dimensional-PAGE Coupled with nLC-MS/MS-Based Identification of Differentially Expressed Proteins and Tumorigenic Pathways in MCF7 Breast Cancer Cells Transfected for JTB Protein Silencing

The identification of new cancer-associated genes/proteins, the characterization of their expression variation, the interactomics-based assessment of differentially expressed genes/proteins (DEGs/DEPs), and understanding the tumorigenic pathways and biological processes involved in BC genesis and progression are necessary and possible by the rapid and recent advances in bioinformatics and molecular profiling strategies. Taking into account the opinion of other authors, as well as based on our own team's in vitro studies, we suggest that the human jumping translocation breakpoint (hJTB) protein might be considered as a tumor biomarker for BC and should be studied as a target for BC therapy. In this study, we identify DEPs, carcinogenic pathways, and biological processes associated with JTB silencing, using 2D-PAGE coupled with nano-liquid chromatography tandem mass spectrometry (nLC-MS/MS) proteomics applied to a MCF7 breast cancer cell line, for complementing and completing our previous results based on SDS-PAGE, as well as in-solution proteomics of MCF7 cells transfected for JTB downregulation. The functions of significant DEPs are analyzed using GSEA and KEGG analyses. Almost all DEPs exert pro-tumorigenic effects in the JTBlow condition, sustaining the tumor suppressive function of JTB. Thus, the identified DEPs are involved in several signaling and metabolic pathways that play pro-tumorigenic roles: EMT, ERK/MAPK, PI3K/AKT, Wnt/β-catenin, mTOR, C-MYC, NF-κB, IFN-γ and IFN-α responses, UPR, and glycolysis/gluconeogenesis. These pathways sustain cancer cell growth, adhesion, survival, proliferation, invasion, metastasis, resistance to apoptosis, tight junctions and cytoskeleton reorganization, the maintenance of stemness, metabolic reprogramming, survival in a hostile environment, and sustain a poor clinical outcome. In conclusion, JTB silencing might increase the neoplastic phenotype and behavior of the MCF7 BC cell line. The data is available via ProteomeXchange with the identifier PXD046265.

Nuclear localization of TET2 requires β-catenin activation and correlates with favourable prognosis in colorectal cancer

Mutation-induced malfunction of ten-eleven translocation methylcytosine dioxygenase 2 (TET2) is widely reported in haematological malignancies. However, the role of TET2 in solid cancers, including colorectal cancer (CRC), is unclear. Here, we found that TET2 malfunction in CRC is mostly due to decreased nuclear localization and that nuclear localization of TET2 is correlated with better survival of patients. To explore the underlying mechanisms, 14 immortalized solid tumour cell lines and 12 primary CRC cell lines were used. TET2 was mostly detected in the nucleus, and it induced significant DNA demethylation and suppressed cell growth by demethylating RORA and SPARC in cell lines like SW480. While in cell lines like SW620, TET2 was observed in the cytosol and did not affect DNA methylation or cell growth. Further examination with immunoprecipitation-mass spectrometry illustrated that β-catenin activation was indispensable for the nuclear localization and tumour suppression effects of TET2. In addition, the β-catenin pathway activator IM12 and the TET2 activator vitamin C were used simultaneously to enhance the effects of TET2 under low-expression conditions, and synergistic inhibitory effects on the growth of cancer were observed both in vitro and in vivo. Collectively, these data suggest that β-catenin-mediated nuclear localization of TET2 is an important therapeutic target for solid tumours.

Mechanisms of tumor-associated macrophages affecting the progression of hepatocellular carcinoma

Tumor-associated macrophages (TAMs) are essential components of the immune cell stroma of hepatocellular carcinoma. TAMs originate from monocytic myeloid-derived suppressor cells, peripheral blood monocytes, and kupffer cells. The recruitment of monocytes to the HCC tumor microenvironment is facilitated by various factors, leading to their differentiation into TAMs with unique phenotypes. TAMs can directly activate or inhibit the nuclear factor-κB, interleukin-6/signal transducer and signal transducer and activator of transcription 3, Wnt/β-catenin, transforming growth factor-β1/bone morphogenetic protein, and extracellular signal-regulated kinase 1/2 signaling pathways in tumor cells and interact with other immune cells via producing cytokines and extracellular vesicles, thus affecting carcinoma cell proliferation, invasive and migratory, angiogenesis, liver fibrosis progression, and other processes to participate in different stages of tumor progression. In recent years, TAMs have received much attention as a prospective treatment target for HCC. This review describes the origin and characteristics of TAMs and their mechanism of action in the occurrence and development of HCC to offer a theoretical foundation for further clinical research of TAMs.

Constitutive Occurrence of E:N-cadherin Heterodimers in Adherens Junctions of Hepatocytes and Derived Tumors

Cell–cell junctions are pivotal for embryogenesis and tissue homeostasis but also play a major role in tumorigenesis, tumor invasion, and metastasis. E-cadherin (CDH1) and N-cadherin (CDH2) are two adherens junction’s transmembrane glycoproteins with tissue-specific expression patterns in epithelial and neural/mesenchymal cells. Aberrant expression has been implicated in the process of epithelial–mesenchymal transition (EMT) in malignant tumors. We could hitherto demonstrate cis-E:N-cadherin heterodimer in endoderm-derived cells. Using immunoprecipitation in cultured cells of the line PLC as well as in human hepatocellular carcinoma (HCC)-lysates, we isolated E-N-cadherin heterodimers in a complex with the plaque proteins α- and β-catenin, plakoglobin, and vinculin. In confocal laser scanning microscopy, E-cadherin co-localized with N-cadherin at the basolateral membrane of normal hepatocytes, hepatocellular adenoma (HCA), and in most cases of HCC. In addition, we analyzed E- and N-cadherin expression via immunohistochemistry in a large cohort of 868 HCCs from 570 patients, 25 HCA, and respective non-neoplastic liver tissue, and correlated our results with multiple prognostic markers. While E- or N-cadherin were similarly expressed in tumor sites with vascular invasion or HCC metastases, HCC with vascular encapsulated tumor clusters (VETC) displayed slightly reduced E-cadherin, and slightly increased N-cadherin expression. Analyzing The Cancer Genome Atlas patient cohort, we found that reduced mRNA levels of CDH1, but not CDH2 were significantly associated with unfavorable prognosis; however, in multivariate analysis, CDH1 did not correlate with prognosis. In summary, E- and N-cadherin are specific markers for hepatocytes and derived HCA and HCC. E:N-cadherin heterodimers are constitutively expressed in the hepatocytic lineage and only slightly altered in malignant progression, thereby not complying with the concept of EMT.

Spontaneous activity of the mitochondrial apoptosis pathway drives chromosomal defects, the appearance of micronuclei and cancer metastasis through the Caspase-Activated DNAse

Micronuclei are DNA-containing structures separate from the nucleus found in cancer cells. Micronuclei are recognized by the immune sensor axis cGAS/STING, driving cancer metastasis. The mitochondrial apoptosis apparatus can be experimentally triggered to a non-apoptotic level, and this can drive the appearance of micronuclei through the Caspase-activated DNAse (CAD). We tested whether spontaneously appearing micronuclei in cancer cells are linked to sub-lethal apoptotic signals. Inhibition of mitochondrial apoptosis or of CAD reduced the number of micronuclei in tumor cell lines as well as the number of chromosomal misalignments in tumor cells and intestinal organoids. Blockade of mitochondrial apoptosis or deletion of CAD reduced, while experimental activation CAD, STING-dependently, enhanced aggressive growth of tumor cells in vitro. Deletion of CAD from human cancer cells reduced metastasis in xenograft models. CAD-deficient cells displayed a substantially altered gene-expression profile, and a CAD-associated gene expression ‘signature’ strongly predicted survival in cancer patients. Thus, low-level activity in the mitochondrial apoptosis apparatus operates through CAD-dependent gene-induction and STING-activation and has substantial impact on metastasis in cancer.

Epithelial-mesenchymal transition process during embryo implantation

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

Inhibition of CXCR2 plays a pivotal role in re-sensitizing ovarian cancer to cisplatin treatment

cDNA microarray data conducted by our group revealed overexpression of CXCL2 and CXCL8 in ovarian cancer (OC) microenvironment. Herein, we have proven that the chemokine receptor, CXCR2, is a pivotal molecule in re-sensitizing OC to cisplatin, and its inhibition decreases cell proliferation, viability, tumor size in cisplatin-resistant cells, as well as reversed the overexpression of mesenchymal epithelium transition markers. Altogether, our study indicates a central effect of CXCR2 in preventing tumor progression, due to acquisition of cisplatin chemoresistant phenotype by tumor cells, and patients' high lethality rate. We found that the overexpression of CXCR2 by OC cells is persistent and anomalously confined to the cellular nuclei, thus pointing to an urge in developing highly lipophilic molecules that promptly permeate cells, bind to and inhibit nuclear CXCR2 to fight OC, instead of relying on the high-cost genetic engineered cells.

The role of microRNAs in epithelial to mesenchymal transition and cancers; focusing on mir-200 family

Epithelial to mesenchymal transition (EMT) is a process associated with cancer malignancy and metastases. Cells undergoing EMT lose their epithelial phenotype and acquire mesenchymal phenotype. This process is accompanied by several molecular changes such as decrease of E-cadherin and increase of N-cadherin which is called the "cadherin swich". MicroRNAs (miRNAs, miRs) are small non-coding RNAs having ability to regulate genes post-transcriptionally. Nowadays they are believed to take part in multiple physiological and pathological processes including cancer development. Comparison between TargetScan7 (www.targetscan.org) results for miR-200b and metanalysis of genes involved in EMT showed that miR-200b has a potential binding site in 60 genes that are involved in EMT (the majority of them were associated with mesenchymal phenotype). Our review summarizes literature findings contributing to experimentally proven interactions between miR-200b and genes involved in EMT process including cell receptors, signaling pathways, cell cycle or cell adhesion. The results of those interactions indicate that miR-200b may have an inhibitory impact on EMT or even in selected cases is able to restore epithelial phenotype.

New Actors Driving the Epithelial-Mesenchymal Transition in Cancer: The Role of Leptin

Leptin is a hormone secreted mainly by adipocytes; physiologically, it participates in the control of appetite and energy expenditure. However, it has also been linked to tumor progression in different epithelial cancers. In this review, we describe the effect of leptin on epithelial-mesenchymal transition (EMT) markers in different study models, including in vitro, in vivo, and patient studies and in various types of cancer, including breast, prostate, lung, and ovarian cancer. The different studies report that leptin promotes the expression of mesenchymal markers and a decrease in epithelial markers, in addition to promoting EMT-related processes such as cell migration and invasion and poor prognosis in patients with cancer. Finally, we report that leptin has the greatest biological relevance in EMT and tumor progression in breast, lung, prostate, esophageal, and ovarian cancer. This relationship could be due to the key role played by the enriched tumor microenvironment in adipose tissue. Together, these findings demonstrate that leptin is a key biomolecule that drives EMT and metastasis in cancer.

Expression of ncRNAs on the DLK1-DIO3 Locus Is Associated With Basal and Mesenchymal Phenotype in Breast Epithelial Progenitor Cells

Epithelial-to-mesenchymal transition (EMT) and its reversed process mesenchymal-to-epithelial transition (MET) play a critical role in epithelial plasticity during development and cancer progression. Among important regulators of these cellular processes are non-coding RNAs (ncRNAs). The imprinted DLK1-DIO3 locus, containing numerous maternally expressed ncRNAs including the lncRNA maternally expressed gene 3 (MEG3) and a cluster of over 50 miRNAs, has been shown to be a modulator of stemness in embryonic stem cells and in cancer progression, potentially through the tumor suppressor role of MEG3. In this study we analyzed the expression pattern and functional role of ncRNAs from the DLK1-DIO3 locus in epithelial plasticity of the breast. We studied their expression in various cell types of breast tissue and revisit the role of the locus in EMT/MET using a breast epithelial progenitor cell line (D492) and its isogenic mesenchymal derivative (D492M). Marked upregulation of ncRNAs from the DLK1-DIO3 locus was seen after EMT induction in two cell line models of EMT. In addition, the expression of MEG3 and the maternally expressed ncRNAs was higher in stromal cells compared to epithelial cell types in primary breast tissue. We also show that expression of MEG3 is concomitant with the expression of the ncRNAs from the DLK1-DIO3 locus and its expression is therefore likely indicative of activation of all ncRNAs at the locus. MEG3 expression is correlated with stromal markers in normal tissue and breast cancer tissue and negatively correlated with the survival of breast cancer patients in two different cohorts. Overexpression of MEG3 using CRISPR activation in a breast epithelial cell line induced partial EMT and enriched for a basal-like phenotype. Conversely, knock down of MEG3 using CRISPR inhibition in a mesenchymal cell line reduced the mesenchymal and basal-like phenotype of the cell line. In summary our study shows that maternally expressed ncRNAs are markers of EMT and suggests that MEG3 is a novel regulator of EMT/MET in breast tissue. Nevertheless, further studies are needed to fully dissect the molecular pathways influenced by non-coding RNAs at the DLK1-DIO3 locus in breast tissue.

Identification of EMT-related high-risk stage II colorectal cancer and characterisation of metastasis-related genes

Background

Our laboratory previously reported an individual-level prognostic signature for patients with stage II colorectal cancer (CRC). However, this signature was not applicable for RNA-sequencing datasets. In this study, we constructed a robust epithelial-to-mesenchymal transition (EMT)- related gene pair prognostic signature.

Methods

Based on EMT-related genes, metastasis-associated gene pairs were identified between metastatic and non-metastatic samples. Then, we selected prognosis-associated gene pairs, which were significantly correlated with disease-free survival of stage II CRC using multivariate Cox regression model, as the EMT-related prognosis signature.

Results

An EMT-related signature composed of fifty-one gene pairs (51-GPS) for prediction-relapse risk of patients with stage II CRC was developed, whose prognostic efficiency was validated in independent datasets. Moreover, 51-GPS achieved better predictive performance than other reported signatures, including a commercial signature Oncotype Dx colon cancer and an immune-related gene pair signature. Besides, EMT-related functional gene sets achieved high enrichment scores in high-risk samples. Especially, loss-of-function antisense approach showed that DEGs between the predicted two clusters were metastasis-related.

Conclusions

The EMT-related gene pair signature can identify the high relapse-risk patients with stage II CRC, which can facilitate individualised management of patients.

Comparative Study of Transcriptomics-Based Scoring Metrics for the Epithelial-Hybrid-Mesenchymal Spectrum

The Epithelial-mesenchymal transition (EMT) is a cellular process implicated in embryonic development, wound healing, and pathological conditions such as cancer metastasis and fibrosis. Cancer cells undergoing EMT exhibit enhanced aggressive behavior characterized by drug resistance, tumor-initiation potential, and the ability to evade the immune system. Recent in silico, in vitro, and in vivo evidence indicates that EMT is not an all-or-none process; instead, cells can stably acquire one or more hybrid epithelial/mesenchymal (E/M) phenotypes which often can be more aggressive than purely E or M cell populations. Thus, the EMT status of cancer cells can prove to be a critical estimate of patient prognosis. Recent attempts have employed different transcriptomics signatures to quantify EMT status in cell lines and patient tumors. However, a comprehensive comparison of these methods, including their accuracy in identifying cells in the hybrid E/M phenotype(s), is lacking. Here, we compare three distinct metrics that score EMT on a continuum, based on the transcriptomics signature of individual samples. Our results demonstrate that these methods exhibit good concordance among themselves in quantifying the extent of EMT in a given sample. Moreover, scoring EMT using any of the three methods discerned that cells can undergo varying extents of EMT across tumor types. Separately, our analysis also identified tumor types with maximum variability in terms of EMT and associated an enrichment of hybrid E/M signatures in these samples. Moreover, we also found that the multinomial logistic regression (MLR)-based metric was capable of distinguishing between "pure" individual hybrid E/M vs. mixtures of E and M cells. Our results, thus, suggest that while any of the three methods can indicate a generic trend in the EMT status of a given cell, the MLR method has two additional advantages: (a) it uses a small number of predictors to calculate the EMT score and (b) it can predict from the transcriptomic signature of a population whether it is comprised of "pure" hybrid E/M cells at the single-cell level or is instead an ensemble of E and M cell subpopulations.

Comparative Study of Transcriptomics-Based Scoring Metrics for the Epithelial-Hybrid-Mesenchymal Spectrum

The Epithelial-mesenchymal transition (EMT) is a cellular process implicated in embryonic development, wound healing, and pathological conditions such as cancer metastasis and fibrosis. Cancer cells undergoing EMT exhibit enhanced aggressive behavior characterized by drug resistance, tumor-initiation potential, and the ability to evade the immune system. Recent in silico, in vitro, and in vivo evidence indicates that EMT is not an all-or-none process; instead, cells can stably acquire one or more hybrid epithelial/mesenchymal (E/M) phenotypes which often can be more aggressive than purely E or M cell populations. Thus, the EMT status of cancer cells can prove to be a critical estimate of patient prognosis. Recent attempts have employed different transcriptomics signatures to quantify EMT status in cell lines and patient tumors. However, a comprehensive comparison of these methods, including their accuracy in identifying cells in the hybrid E/M phenotype(s), is lacking. Here, we compare three distinct metrics that score EMT on a continuum, based on the transcriptomics signature of individual samples. Our results demonstrate that these methods exhibit good concordance among themselves in quantifying the extent of EMT in a given sample. Moreover, scoring EMT using any of the three methods discerned that cells can undergo varying extents of EMT across tumor types. Separately, our analysis also identified tumor types with maximum variability in terms of EMT and associated an enrichment of hybrid E/M signatures in these samples. Moreover, we also found that the multinomial logistic regression (MLR)-based metric was capable of distinguishing between "pure" individual hybrid E/M vs. mixtures of E and M cells. Our results, thus, suggest that while any of the three methods can indicate a generic trend in the EMT status of a given cell, the MLR method has two additional advantages: (a) it uses a small number of predictors to calculate the EMT score and (b) it can predict from the transcriptomic signature of a population whether it is comprised of "pure" hybrid E/M cells at the single-cell level or is instead an ensemble of E and M cell subpopulations.

Integrated use of bioinformatic resources reveals that co-targeting of histone deacetylases, IKBK and SRC inhibits epithelial-mesenchymal transition in cancer

With the advent of high-throughput technologies leading to big data generation, increasing number of gene signatures are being published to predict various features of diseases such as prognosis and patient survival. However, to use these signatures for identifying therapeutic targets, use of additional bioinformatic tools is indispensible part of research. Here, we have generated a pipeline comprised of nearly 15 bioinformatic tools and enrichment statistical methods to propose and validate a drug combination strategy from already approved drugs and present our approach using published pan-cancer epithelial-mesenchymal transition (EMT) signatures as a case study. We observed that histone deacetylases were critical targets to tune expression of multiple epithelial versus mesenchymal genes. Moreover, SRC and IKBK were the principal intracellular kinases regulating multiple signaling pathways. To confirm the anti-EMT efficacy of the proposed target combination in silico, we validated expression of targets in mesenchymal versus epithelial subtypes of ovarian cancer. Additionally, we inhibited the pinpointed proteins in vitro using an invasive lung cancer cell line. We found that whereas low-dose mono-therapy failed to limit cell dispersion from collagen spheroids in a microfluidic device as a metric of EMT, the combination fully inhibited dissociation and invasion of cancer cells toward cocultured endothelial cells. Given the approval status and safety profiles of the suggested drugs, the proposed combination set can be considered in clinical trials.

Histone Modification Marks Strongly Regulate CDH1 Promoter in Prostospheres as A Model of Prostate Cancer Stem Like Cells

OBJECTIVE

Cadherin-1 (CDH1) plays an important role in the metastasis, while expression of this protein is under control of epigenetic changes on its gene promoter. Therefore we evaluated both DNA methylation (DNAmet) and histone modification marks of CDH1 in prostate cancer stem like cells (PCSLCs).

MATERIALS AND METHODS

In this experimental study, we isolated PCSLCs using cell surface marker and prostaspheroid formation, respectively. The cells isolated from both methods were characterized and then the levels of H3K4me2, H3K27me3, H3K9me2/3 and H3K9ac as well as DNAmet were assessed in CDH1 promoter of the isolated cells.

RESULTS

The CD44+ CD49hi cells were not validated as PCSLCs. However, prostaspheres overexpressed stemness related genes and had higher ability of invasion potential, associated with reduction in CDH1 expression. Epigenetic status analysis showed that CDH1 promoter was hypo-methylated. Histone modifications of H3K9ac and H3K4me3 were significantly reduced, in parallel with an increased level of H3K27me3.

CONCLUSION

Our results suggest that slight decrease of DNAmet of the CpG island in CDH1 promoter does not significantly contribute to the change of CDH1 expression. Therefore, histone modifications are responsible in repressing CDH1 in PCSLCs.

OVOL2 induces mesenchymal-to-epithelial transition in fibroblasts and enhances cell-state reprogramming towards epithelial lineages

Mesenchymal-to-epithelial transition (MET) is an important step in cell reprogramming from fibroblasts (a cell type frequently used for this purpose) to various epithelial cell types. However, the mechanism underlying MET induction in fibroblasts remains to be understood. The present study aimed to identify the transcription factors (TFs) that efficiently induce MET in dermal fibroblasts. OVOL2 was identified as a potent inducer of key epithelial genes, and OVOL2 cooperatively enhanced MET induced by HNF1A, TP63, and KLF4, which are known reprogramming TFs to epithelial lineages. In TP63/KLF4-induced keratinocyte-like cell-state reprogramming, OVOL2 greatly facilitated the activation of epithelial and keratinocyte-specific genes. This was accompanied by enhanced changes in chromatin accessibility across the genome. Mechanistically, motif enrichment analysis revealed that the target loci of KLF4 and TP63 become accessible upon induction of TFs, whereas the OVOL2 target loci become inaccessible. This indicates that KLF4 and TP63 positively regulate keratinocyte-associated genes whereas OVOL2 suppresses fibroblast-associated genes. The exogenous expression of OVOL2 therefore disrupts fibroblast lineage identity and facilitates fibroblast cell reprogramming into epithelial lineages cooperatively with tissue-specific reprogramming factors. Identification of OVOL2 as an MET inducer and an epithelial reprogramming enhancer in fibroblasts provides new insights into cellular reprogramming improvement for future applications.

The homeobox transcription factor MSX2 partially mediates the effects of bone morphogenetic protein 4 (BMP4) on somatic cell reprogramming

Bone morphogenetic proteins (BMPs) induce mesenchymal-epithelial transition (MET) and enhance the generation of induced pluripotent stem cells (iPSCs). However, BMPs are also signaling molecules critical for arresting reprogramming in the pre-iPSC state. In this study, using mouse embryonic fibroblasts, we found that the time- and concentration-dependent effects of BMPs on reprogramming are mediated by Msh homeobox 2 (MSX2), a homeobox-containing transcription factor. BMPs up-regulated Msx2 by activating SMAD1/5, and MSX2 then directly bound to the promoters and up-regulated the expression of the cadherin 1 (Cdh1, also known as E-cadherin), GATA-binding protein 3 (Gata3), and Nanog genes. Cdh1 contributed to BMP4- and MSX2-induced MET and subsequently promoted reprogramming. On the other hand, GATA3 promoted reprogramming, possibly by up-regulating Spalt-like transcription factor 4 (SALL4) expression. As key transcriptional factors in maintaining pluripotency, up-regulation of SALL4 and NANOG enhanced reprogramming. Moreover, the ability of MSX2 to up-regulate Cdh1, Gata3, Nanog, and Sall4 was further potentiated in the presence of Krüppel-like factor 4 (KLF4). However, MSX2 did not mediate the effects of BMP4 signaling on activation of the microRNAs miR-205 and miR-200 or the inhibitory effects that arrested reprogramming in the pre-iPSC state. In conclusion, MSX2 partially mediates the effects of BMP4 signaling during reprogramming, improving our understanding of the role of BMP signaling in MET and of the connection between cell lineage specifiers such as MSX2 and GATA3 and pluripotency.

Snail promotes ovarian cancer progression by recruiting myeloid-derived suppressor cells via CXCR2 ligand upregulation

Snail is a major transcriptional factor that induces epithelial-mesenchymal transition (EMT). In this study, we explore the effect of Snail on tumor immunity. Snail knockdown in mouse ovarian cancer cells suppresses tumor growth in immunocompetent mice, associated with an increase of CD8⁺ tumor-infiltrating lymphocytes and a decrease of myeloid-derived suppressor cells (MDSCs). Snail knockdown reduces the expression of CXCR2 ligands (CXCL1 and CXCL2), chemokines that attract MDSCs to the tumor via CXCR2. Snail upregulates CXCR ligands through NF-kB pathway, and most likely, through direct binding to the promoters. A CXCR2 antagonist suppresses MDSC infiltration and delays tumor growth in Snail-expressing mouse tumors. Ovarian cancer patients show elevated serum CXCL1/2, which correlates with Snail expression, MDSC infiltration, and short overall survival. Thus, Snail induces cancer progression via upregulation of CXCR2 ligands and recruitment of MDSCs. Blocking CXCR2 represents an immunological therapeutic approach to inhibit progression of Snail-high tumors undergoing EMT.

Snail is a transcription factor that induces epithelial-mesenchymal transition. Here the authors show that, in the mesenchymal subtype of ovarian cancer, Snail expression promotes tumorigenesis by inducing immune evasion through CXCR2-ligands-mediated recruitment of myeloid-derived suppressor cells.

Epithelial-to-mesenchymal transition in the development of endometriosis

Endometriosis, an estrogen-dependent chronic gynecological disease, is common in reproductive-age women and profoundly affects their life quality. Although various pathogenic theories have been proposed, the origin of endometriosis remains unclear. Epithelial to mesenchymal transition (EMT) is a process that epithelial cells lose polarized organization of the cytoskeleton and cell-to-cell contacts, acquiring the high motility of mesenchymal cells. These changes are thought to be prerequisites for the original establishment of endometriotic lesions. However, no study exactly indicates which type of EMT occurs in endometriosis. In this review, we conclude that two different types of EMT may participate in this disease. Besides, two stimulating signals, hypoxia and estrogen, can through different pathways to activate the EMT process in endometriosis. Those pathways involve many cellular factors such as TGF-beta and Wnt, ultimately leading to cell proliferation and migration. As infertility is becoming a serious and intractable issue for women, EMT, during the implantation process, is gaining attention. In this review, we will describe the known functions of EMT in endometriosis, and suggest further studies that may aid in the development of medical therapy.

EMT and Treatment Resistance in Pancreatic Cancer

Pancreatic cancer (PC) is the third leading cause of adult cancer mortality in the United States. The poor prognosis for patients with PC is mainly due to its aggressive course, the limited efficacy of active systemic treatments, and a metastatic behavior, demonstrated throughout the evolution of the disease. On average, 80% of patients with PC are diagnosed with metastatic disease, and the half of those who undergo surgery and adjuvant therapy develop liver metastasis within two years. Metastatic dissemination is an early event in PC and is mainly attributed to an evolutionary biological process called epithelial-to-mesenchymal transition (EMT). This innate mechanism could have a dual role during embryonic growth and organ differentiation, and in cancer progression, cancer stem cell intravasation, and metastasis settlement. Many of the molecular pathways decisive in EMT progression have been already unraveled, but little is known about the causes behind the induction of this mechanism. EMT is one of the most distinctive and critical features of PC, occurring even in the very first stages of tumor development. This is known as pancreatic intraepithelial neoplasia (PanIN) and leads to early dissemination, drug resistance, and unfavorable prognosis and survival. The intention of this review is to shed new light on the critical role assumed by EMT during PC progression, with a particular focus on its role in PC resistance.

Epithelial-mesenchymal transition and cancer stem cell-like phenotype induced by Twist1 contribute to acquired resistance to irinotecan in colon cancer

Inherent and acquired chemoresistance reduce the effectiveness of irinotecan in the treatment of metastatic colorectal cancer (CRC). However, the molecular mechanisms underlying this resistance process are still unclear. Twist1 is one of the master transcription factors of epithelial-mesenchymal transition (EMT). Our previous study indicated that Twist1 is overexpressed in colon cancer tissues, and demonstrated that Twist1 plays a crucial role in the chemoresistance of CRC. In the present study, we further investigated how Twist1 contribute to acquired resistance to irinotecan in colon cancer. The irinotecan-resistant cells were established by gradual adaptation of increasing irinotecan concentrations in LoVo cells, named LoVo/CPT-11R cells. Results showed that cell viabilities to different anticancer drugs were markedly increased in LoVo/CPT-11R cells compared to LoVo cells. Moreover, LoVo/CPT-11R cells displayed EMT, CSC-like cellular morphology and relative biomarkers were also significantly increased. In addition, overexpressed Twist1 LoVo cells were established by lentivirus transfection assay, named LoVo/Twist1 cells. Results showed that the LoVo/Twist1 cells perform a distinctly decreased sensitivity to irinotecan, downregulated expression of E-cadherin, upregulated expression of cluster of differentiation 44 (CD44), and a significant enhancement of invasion and migration potential by regulation of MMP2 compared with control cells. In contrast, the inhibition of Twist1 transfected with siRNA could enhance the irinotecan sensitivity in LoVo/CPT-11R cells and downregulate the expression of vimentin and CD44. Our data provide evidence that EMT and CSC-like phenotype induced by Twist1 contribute to acquire resistance to irinotecan and enhanced migration and invasion in colon cancer.

Sequential EMT-MET induces neuronal conversion through Sox2

Direct neuronal conversion can be achieved with combinations of small-molecule compounds and growth factors. Here, by studying the first or induction phase of the neuronal conversion induced by defined 5C medium, we show that the Sox2-mediated switch from early epithelial-mesenchymal transition (EMT) to late mesenchymal-epithelial transition (MET) within a high proliferation context is essential and sufficient for the conversion from mouse embryonic fibroblasts (MEFs) to TuJ⁺ cells. At the early stage, insulin and basic fibroblast growth factor (bFGF)-induced cell proliferation, early EMT, the up-regulation of Stat3 and Sox2, and the subsequent activation of neuron projection. Up-regulated Sox2 then induced MET and directed cells towards a neuronal fate at the late stage. Inhibiting either stage of this sequential EMT-MET impaired the conversion. In addition, Sox2 could replace sequential EMT-MET to induce a similar conversion within a high proliferation context, and its functions were confirmed with other neuronal conversion protocols and MEFs reprogramming. Therefore, the critical roles of the sequential EMT-MET were implicated in direct cell fate conversion in addition to reprogramming, embryonic development and cancer progression.

HOXB8 promotes tumor metastasis and the epithelial-mesenchymal transition via ZEB2 targets in gastric cancer

PURPOSE

The homeobox B8 (HOXB8) functions as a sequence-specific transcription factor that is involved in development. Increased expression of this gene is associated with a wide variety of tumor; however, its function in gastric cancer has not been clarified. In the present study, the expression of HOXB8 in gastric cancer tissues and influence of HOXB8 on gastric cancer cellular were evaluated.

METHODS

The expression levels of HOXB8 mRNA in human gastric cancer tissues were analyzed through quantitative RT-PCR. To test the role of HOXB8 in gastric cancer metastasis, the cell transwell assay was performed. Microarray, ChIP-qPCR, and Western blot were used to explore the possible mechanism that HOXB8 promotes gastric cancer cells metastasis.

RESULTS

In this study, we found that HOXB8 showed higher expression in metastatic tissues than no-metastatic tissues. Overexpression of HOXB8 can promote gastric cancer cells migration and invasion, while silencing HOXB8 leads to the opposite results. Overexpression of HOXB8 also increases the rate of metastasis in NCI-N87 mice, while silencing HOXB8 has the opposite results. Furthermore, HOXB8 promotes epithelial-mesenchymal transformation of AGS cells. We also found that ZEB2 can interact with HOXB8 and may be a downstream factor of HOXB8 by using microarray. Knockdown of ZEB2 can inhibit HOXB8-induced migration and invasion capacity, as well as the epithelial-mesenchymal transformation in gastric cancer cells.

CONCLUSIONS

The results showed that HOXB8 plays an important role in the development and metastasis of gastric carcinoma.

Genome-wide gain-of-function screen for genes that induce epithelial-to-mesenchymal transition in breast cancer

Epithelial to mesenchymal transition (EMT) is a developmental program that has been implicated in progression, metastasis and therapeutic resistance of some carcinomas. To identify genes whose overexpression drives EMT, we screened a lentiviral expression library of 17000 human open reading frames (ORFs) using high-content imaging to quantitate cytoplasmic vimentin. Hits capable of increasing vimentin in the mammary carcinoma-derived cell line MDA-MB-468 were confirmed in the non-tumorigenic breast-epithelial cell line MCF10A. When overexpressed in this model, they increased the rate of cell invasion through Matrigel™, induced mesenchymal marker expression and reduced expression of the epithelial marker E-cadherin. In gene-expression datasets derived from breast cancer patients, the expression of several novel genes correlated with expression of known EMT marker genes, indicating their in vivo relevance. As EMT-associated properties are thought to contribute in several ways to cancer progression, genes identified in this study may represent novel targets for anti-cancer therapy.