Importance Of Epithelial-mesenchymal Transition Research Articles

Is Epithelial-Mesenchymal Transition a New Roadway in the Pathogenesis of Oral Submucous Fibrosis: A Comprehensive Review.

Epithelial-mesenchymal transition (EMT) collectively refers to a series of episodes that reshape polarized, intact epithelial cells into discrete motile cells that can conquer the extracellular matrix (ECM). It performs a pivotal role in embryonic development, wound healing, and tissue repair. Surprisingly, the exact mechanism can also lead to the onset of malignancy and organ fibrosis contributing to scar formation and loss of function. transforming growth factor signaling, WNT signaling, Notch signaling, Hedgehog signaling, and receptor tyrosine kinase signaling, as well as non-transcriptional changes in response to extracellular cues, such as growth factors and cytokines, hypoxia, and contact with the surrounding ECM, are responsible for the initiation of EMT. Although the pathogenesis of oral submucous fibrosis (OSMF) is multifactorial, compelling evidence suggests that it results from collagen deregulation. EMT is one of the spotlight events in the pathogenesis of OSMF, with myofibroblasts and keratinocytes being the victim cells. EMT is an essential step in both physiological and pathological events. The importance of EMT in the malignant development of OSMF and the inflammatory reaction preceding fibrosis implies a new upcoming area of research. This review aims to focus on the EMTevents that function as a double-edged sword between wound healing and fibrosis and further discuss the mechanisms along with the molecular pathways that direct changes in gene expression essential for the same in the oral cavity. As OSMF involves a risk of malignant transformation, understanding the cellular and molecular events will open more avenues for therapeutic breakthroughs targeting EMT.

The Role of Long Non-Coding RNAs in Epithelial-Mesenchymal Transition-Related Signaling Pathways in Prostate Cancer.

Prostate cancer (PCa) is one of the most common male malignancies with frequent remote invasion and metastasis, leading to high mortality. Epithelial-mesenchymal transition (EMT) is a fundamental process in embryonic development and plays a key role in tumor proliferation, invasion and metastasis. Numerous long non-coding RNAs (lncRNAs) could regulate the occurrence and development of EMT through various complex molecular mechanisms involving multiple signaling pathways in PCa. Given the importance of EMT and lncRNAs in the progression of tumor metastasis, we recapitulate the research progress of EMT-related signaling pathways regulated by lncRNAs in PCa, including AR signaling, STAT3 signaling, Wnt/β-catenin signaling, PTEN/PI3K/AKT signaling, TGF-β/Smad and NF-κB signaling pathways. Furthermore, we summarize four modes of how lncRNAs participate in the EMT process of PCa via regulating relevant signaling pathways.

TGF-β1 increases cellular invasion of colorectal neuroendocrine carcinoma cell line through partial epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) plays a pivotal role in cancer progression and metastasis in many types of malignancies, including colorectal cancer. Although the importance of EMT is also considered in colorectal neuroendocrine carcinoma (NEC), its regulatory mechanisms have not been elucidated. We recently established a human colorectal NEC cell line, SS-2. In this study, we aimed to clarify whether these cells were sensitive to transforming growth factor beta 1 (TGF-β1) and whether EMT could be induced through TGF-β1/Smad signaling, with the corresponding NEC cell-specific changes in invasiveness. In SS-2 cells, activation of TGF-β1 signaling, as indicated by phosphorylation of Smad2/3, was dose-dependent, demonstrating that SS-2 cells were responsive to TGF-β1. Analysis of EMT markers showed that mRNA levels changed with TGF-β1 treatment and that E-cadherin, an EMT marker, was expressed in cell-cell junctions even after TGF-β1 treatment. Invasion assays showed that TGF-β1-treated SS-2 cells invaded more rapidly than non-treated cells, and these cells demonstrated increased metalloproteinase activity and cell adhesion. Among integrins involved in cell-to-matrix adhesion, α2-integrin was exclusively upregulated in TGF-β1-treated SS-2 cells, but not in other colon cancer cell lines, and adhesion and invasion were inhibited by an anti-α2-integrin blocking antibody. Our findings suggest that α2-integrin may represent a novel therapeutic target for the metastasis of colorectal NEC cells.

Molecular Orchestration of Epithelial Mesenchymal Transition During Trophoblast and Placental Development

In Eutherian mammals, placenta is a highly specialized extra-embryonic organ that provides the feto-maternal interface and modulates the uterine environment conducive to successful pregnancy. Placenta originates from trophectoderm cells of the blastocyst and is comprised of various lineages of trophoblast cells, endothelial and smooth muscle cells. Since trophectoderm cells are epithelial in nature, it is obvious that epithelial mesenchymal transition (EMT) is a hallmark of placentation. In this report, we aimed to identify the molecular signature that regulates EMT during trophoblast and placental development in mice. On E7.5 onwards the trophoblast stem cells located in ectoplacental cone rapidly divides, differentiate leading to formation of placenta proper. Functional EMT transcriptome in mouse implantation sites on E7.5 and E9.5 were analyzed using a RT2 profiler real time PCR array scanning 84 EMT related genes. Validation of the array was performed using real time q-PCR and western blot analyses. Array result showed that there was an overall reduction of EMT gene expression in the implantation site as gestation progressed from E7.5 to E9.5 albeit the levels of EMT gene expression were substantial on both days. The differentially expressed EMT genes were further assessed during a) placental development using mouse placental samples from various days of gestation, b) induction of either EMT or differentiation in trophoblast stem (TS) cells using western blot analysis. The genes thus identified include transcription factors (Esr1, Snai2, Stat3, Foxc2), mesenchymal markers (Vim, Fn1), extracellular matrix and cell adhesion genes (Col1a2, Col3a1, Itga5, Vcan), migration and motility genes (Msn, Fn1, Pdgfrb). Extent of EMT gene expression was highest in placenta from E12.5 of mouse gestation. In addition, ectopic administration of EMT inducer led to the induction of EMT in TS cells as evidenced by EMT gene expression profile. Furthermore, differentiation of TS cells to other trophoblast lineages led to decline in EMT gene expression. Our data thus provides new insights into the importance of EMT during trophoblast stem cell differentiation and placental morphogenesis.

THE ROLE AND MECHANISMS OF EPITHELIAL-MESENCHYMAL TRANSITION IN THE PROGRESSION OF MELANOMA

Despite the achievements of modern medicine in the diagnosis and treatment of oncological diseases, skin melanoma remains one of the leading causes of death worldwide: every third case of melanoma ends in death. As you know, one of the main causes of death is the high incidence of melanoma progression. It is important to note that the mechanisms of melanoma progression are diverse and the rapidly developing area of drug therapy for tumors requires a deep understanding of their characteristics. This is primarily due to the fact that these processes lead to the formation of special, minor tumor clones with stem properties. They are highly resistant to therapy. The latter is the mainobstacle to effective treatment of melanoma patients. The epithelial-mesenchymal transition (EMT) plays a leading role in the acquisition of metastatic potential by melanoma cells. An important distinguishing feature of EMT is a change in the level of expression of transmembrane glycoproteins involved in cell adhesion. With EMT, both a decrease in the level of E-cadherin and an increase in the expression of N-cadherin are observed. Such a switch in different classes of adhesion molecules leads to the fact that melanoma cells lose contact with neighboring keratinocytes and begin to interact with fibroblasts and endothelial cells. The key regulator in EMT induction in melanoma is the Notch1 signaling pathway, which accelerates N-cadherin expression when activated. In addition, EMT also regulates many other pathways – RAS/RAF/MEK/ERK, PI3K/AKT/mTOR, Wnt/β-catenin, the dysregulation of which is associated with the development of drug resistance in melanoma. The analysis was carried out in the article of modern literature data on the importance of EMT in carcinogenesis and prognosis of melanoma. The modern mechanisms of EMT, currently known prognostic factors, as well as potential therapeutic targets that affect EMT and, accordingly, inhibit the process of metastasis, are described in detail.

The importance of epithelial-mesenchymal transition and autophagy in cancer drug resistance

Epithelial-mesenchymal transition (EMT) and autophagy are both known to play important roles in the development of cancer. Subsequently, these processes are now being utilised as targets for therapy. Cancer is globally one of the leading causes of death, and, despite many advances in treatment options, patients still face many challenges. Drug resistance in cancer-therapy is a large problem, and both EMT and autophagy have been shown to contribute. However, given the context-dependent role of these processes and the complexity of the interactions between them, elucidating how they both act alone and interact is important. In this review, we provide insight into the current landscape of the interactions of autophagy and EMT in the context of malignancy, and how this ultimately may affect drug resistance in cancer therapy.

Epithelial-mesenchymal transition in Crohn's disease.

Crohn's disease (CD) is often accompanied by the complications of intestinal strictures and fistulas. These complications remain obstacles in CD treatment. In recent years, the importance of epithelial-mesenchymal transition in the pathogenesis of CD-associated fistulas and intestinal fibrosis has become apparent. Epithelial-mesenchymal transition refers to a dynamic change, wherein epithelial cells lose their polarity and adherence and acquire migratory function and fibroblast features. During formation of CD-associated fistulas, intestinal epithelial cells dislocate from the basement membrane and migrate to the lining of the fistula tracts, where they convert into transitional cells as a compensatory response under the insufficient wound healing condition. In CD-associated intestinal fibrosis, epithelial-mesenchymal transition may serve as a source of new fibroblasts and consequently lead to overproduction of extracellular matrix. In this review, we present current knowledge of epithelial-mesenchymal transition and its role in the pathogenesis of CD in order to highlight new therapy targets for the associated complications.

Abstract 3422: miR-200c-driven mesenchymal-to-epithelial transition as a therapeutic target in uterine carcinosarcomas

Abstract Introduction and purpose of study: Uterine carcinosarcoma (UCS) is an aggressive and rare malignancy with poor prognosis and limited treatment options. These biphasic tumors, consisting of epithelial and mesenchymal components, are hypothesized to evolve from less aggressive endometrial adenocarcinomas (EACs) through epithelial-mesenchymal transition (EMT). EMT is a reversible process, and mesenchymal-epithelial transition (MET) has been shown to decrease tumor aggressiveness. Inducing MET has been suggested for treatment of cancers with a mesenchymal phenotype. In our studies, we investigated the importance of EMT in the evolution of UCS by depleting miR-200, a family of microRNAs critical for EMT, in EAC cell lines. We also explored the role of miR-200 overexpression as a driving force for MET in UCS with a focus on finding novel therapeutic approaches to the treatment of this aggressive disease. Experimental procedures: To test whether UCSs evolve from EACs, we depleted miR-200b/c in EAC cell lines, Ishikawa and MFE-280. For the MET studies, we stably overexpressed miR-200c in UCS cell lines, SNU685 and JHUCS1. Gene expression was measured using TaqMan and whole transcriptome sequencing (RNA-seq) assays. Immunoblotting was performed on the EMT-relevant proteins. Cell adhesion and in vitro cell proliferation were measured using commercially available assays. In vivo tumor growth of JHUCS1 miR-200c-overexpressed cells was measured in xenografted mice. Summary of the data: Compared to EAC cells, UCS cells had undetectable miR-200c expression. Depletion of miR-200b/c in EAC cells resulted in expected increased ZEB1 and decreased E-cadherin expression. The lack of increased N-cadherin, vimentin and morphologic changes, even in the presence of exogenous TGF-β suggests partial EMT induction. Overexpression of miR-200c in UCS cells resulted in full MET, with a decrease in ZEB1, ZEB2, N-cadherin and vimentin and an increase in E-cadherin. Increased cellular adhesion was observed along with typical MET morphologic changes. miR-200c overexpression led to inhibited UCS cell proliferation and metabolic activity. Overexpression of miR-200c in vivo resulted in substantially smaller tumors compared to mice bearing control UCS cells. Conclusions: Our data suggest that mechanisms additional to, or other than EMT, are necessary for the evolution of UCS from EAC. UCS cell lines, however, readily undergo robust MET in the setting of increased miR-200c expression rendering them less aggressive. These findings suggest that miR200 overexpression through advanced microRNA therapeutics may lead to new options for the treatment of uterine carcinosarcomas. Citation Format: Jill H. Tseng, Maria Bisogna, Lien N. Hoang, Narciso Olvera, Douglas A. Levine, Petar Jelinic. miR-200c-driven mesenchymal-to-epithelial transition as a therapeutic target in uterine carcinosarcomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3422. doi:10.1158/1538-7445.AM2017-3422

EMT and Anti-EMT Strategies in Cancer

This article discusses the role of epithelial mesenchymal transition (EMT) and addresses the scientific merits on epigenetic regulation of EMT. The importance of EMT as a prognostic biomarker is explored and the rationale on application of multitargeted epigenetic therapy is discussed. We describe a literature review of the epigenetic influence of such process and we present a potentially effective method to reverse the epigenetic switch in favor for MET, in a clinical setting. A case series of advanced solid tumors are summarized aiming at generating hypothesis for the future recommendations for clinical trials targeting the tumor’s biological behavior through inhibition of EMT. Hypothesis: We propose an integral and integrative approach that can modify tumor’s biological behavior through inhibition of EMT, and further reduce the chances of metastasis, that can translate to improved outcome and patient’s survival in advanced disease.

Abstract B48: Spatiotemporal regulation of epithelial-mesenchymal transition is essential for carcinoma metastasis

Abstract During metastasis, epithelial tumor cells dissociate from each other, invade surrounding extracellular matrix, disseminate into the systemic circulation, and then establish secondary lesions in distant sites. A developmental program termed Epithelial-Mesenchymal Transition (EMT) has been implicated in giving rise to the dissemination of single carcinoma cells. During EMT, stationary epithelial cells undergo a series of cellular and molecular changes to convert into motile mesenchymal cells. However, the involvement of EMT in tumor metastasis is still controversial primarily due to the lack of a mesenchymal phenotype in human carcinoma distant metastases. In this study, we established a transgenic mouse model that specifically expresses the EMT-inducing transcription factor Twist1 on the basal layer of the skin in an inducible fashion. Using a chemical carcinogenesis skin tumor model, we report here that induction of Twist1 is sufficient to promote carcinoma cells to undergo EMT, invade through basement membrane, intravasate into blood circulation, and extravasate into distant organs. More importantly, we found that in distant sites, turning off Twist1 to allow reversion of EMT is essential for tumor cells to proliferate and form epithelial macrometastases. In contrast, continuous expression of Twist1 in disseminated tumor cells inhibits metastasis formation in distant organs. Consistent with these results, we found that expression of Twist1 is significantly higher in primary human carcinomas compared to their corresponding distant metastases. These results indicate that carcinoma cells undergo EMT to disseminate; once reaching distant site, they need to revert to an epithelial identity to form macrometastases. Our study demonstrates in vivo the requirement of “reversible EMT” in tumor metastasis and may resolve the controversy on the importance of EMT in carcinoma metastasis. EMT features are frequently observed in many types of primary human carcinoma, but not their corresponding metastases. Our findings indicate that reversible EMT likely represents a key driving force in human carcinoma metastasis. Delayed onset of metastasis following primary tumor removal is thought to be due to resurrection of latent carcinoma cells in distant organs. Our study raises the possibility that tumor dormancy could be due to the inability of disseminated tumor cells to revert EMT and proliferate. The dynamic involvement of EMT in metastasis cautions that therapies inhibiting EMT could be counterproductive in preventing distant metastases when patients already present circulating tumor cells. Instead, blocking EMT reversion may prevent dormant tumor cells from establishing macrometastases. Citation Format: Jeff H. Tsai, Joana Liu Donaher, Danielle A. Murphy, Sandra Chau, Jing Yang. Spatiotemporal regulation of epithelial-mesenchymal transition is essential for carcinoma metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B48.

Abstract P5-04-05: E-Cadherin is Required for In Vivo Growth of Inflammatory Breast Cancer: Importance of Mesenchymal-Epithelial Transition (MET) and Role of HIF1α

Abstract Background: Inflammatory breast cancer (IBC) is the most aggressive and deadly form of breast cancer and is phenotypically distinct from other forms of locally advanced breast cancer. The 5-year survival for IBC patients (40%) has not improved even with the implementation of multi-disciplinary care and targeted therapies (e.g. anti-HER2 or anti-estrogen therapies). Lymph node involvement is common at first diagnosis and the accelerated metastasis program that characterizes IBC account for a disproportionate number of the 40,000 women who will die from breast cancer. The most common molecular marker for IBC is the cell adhesion surface glycoprotein, E-Cadherin. Classically, E-Cadherin is thought to be a tumor suppressor and its loss is associated with the epithelial-mesenchymal transition (EMT) and acquisition of an invasive phenotype. The importance of EMT in metastasis is well accepted in numerous tumor models although the presence of EMT in patient samples is rarely demonstrated. Given the propensity of IBC to metastasize, one would expect a strong EMT signature in IBC cell lines, however the persistent robust expression of E-Cadherin in IBC patient tumors and in IBC cell lines, with a lack of expression of ZEB1, a transcriptional repressor of E-cadherin and diminished expression of genes within the transforming growth factor beta signaling pathway, suggests otherwise. Methods: To further define the role of E-Cadherin in IBC, we used the SUM149 IBC cell line to manipulate E-Cadherin via shRNA knockdown and by overexpression of ZEB1 a known transcriptional repressor of E-cadherin. Results: While the lack of E-Cadherin or ZEB1 overexpression in SUM149 cells led to an EMT phenotype in vitro, E-Cadherin was required for in vivo growth of SUM149 tumor cells. Gene profiling identified novel E-Cadherin signaling pathways including an hypoxia gene signature through HIF1a as well as cytokine responsive pathways. The requirement of HIF-1a for in vivo growth of SUM149 cells was confirmed by shRNA knockdown of HIF-1a. Conclusions: The absolute requirement for E-Cadherin and maintenance of the mesenchymal-epithelial transition in IBC tumor growth is demonstrated. Furthermore, a novel functional link between E-Cadherin and HIF-1a and in their critical role in survival of IBC tumors is identified for the first time and warrants further investigation. Supported in part by The Susan G Komen Organization Promise Grant KG081287 (FMR and MC) Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-04-05.

Spatiotemporal Regulation of Epithelial-Mesenchymal Transition Is Essential for Squamous Cell Carcinoma Metastasis

Epithelial-mesenchymal transition (EMT) is implicated in converting stationary epithelial tumor cells into motile mesenchymal cells during metastasis. However, the involvement of EMT in metastasis is still controversial, due to the lack of a mesenchymal phenotype in human carcinoma metastases. Using a spontaneous squamous cell carcinoma mouse model, we show that activation of the EMT-inducing transcription factor Twist1 is sufficient to promote carcinoma cells to undergo EMT and disseminate into blood circulation. Importantly, in distant sites, turning off Twist1 to allow reversion of EMT is essential for disseminated tumor cells to proliferate and form metastases. Our study demonstrates invivo the requirement of "reversible EMT" in tumor metastasis and may resolve the controversy on the importance of EMT in carcinoma metastasis.

Abstract 2414: The inhibitory effect of heat treatment against Epithelial-Mesenchymal Transition (EMT) in human colon adenocarcinoma cell line

Abstract Background and Aim: In order to improve the prognosis of patients with advanced cancer, novel interventions for metastatic disease are required. While anti-tumor effects of hyperthermia have been well studied and assessed, its effects on cancer metastasis is unknown. We reported that the production of transforming growth factor-β (TGF-β) by cancer cell lines was reduced by the heat treatment, furthermore the production of the intratumoral TGF-β was also reduced by whole body hyperthermia in mouse subcutaneous tumor model. Recently, the importance of Epithelial-Mesenchymal Transition (EMT) in the progression of many cancers is recognized and many studies have shown that transforming growth factor-β (TGF-β) can induce EMT. Therefore, it is expected that heat treatment could inhibit TGF-β-induced EMT. In this study, we investigated the inhibitory effect of the heat treatment on TGF-β-induced EMT in the human colon adenocarcinoma cells. Methods: To study the effects of heat treatment on EMT, human colon adenocarcinoma cell line, HT29 cell, was used and treated with heat (43 degrees Celsius) for 1 h followed by the stimulation of TGF-β (10ng/ml). HT29 cells were examined for morphological changes using the inverted phases-contrast microscope, and the localization of E-cadherin as the epithelial adhesion factor on the cell was analyzed with fluorescent immunostaining using confocal microscope. The EMT-related factors such as vimentin, fibronectin, ZEB-1, Snail were analyzed by RT-PCR. Furthermore, the activation of nuclear factor kappa B (NF-κB) was analyzed in the nuclear extracts using an ELISA method. Results: After treatment with TGF-β, HT29 cells changed their morphology from a typical epithelium to mesenchymal spindle-shaped, and this morphological change was attenuated by the heat treatment. The expression of E-cadherin, which is the component of epithelial adhesion, was down-regulated by TGF-β, and this effect was attenuated when HT29 cells were treated with heat before the stimulation with TGF-β. The up-regulation of EMT-related factors such as fibronectin and Snail induced by TGF-β was decreased by the heat treatment. Furthermore, TGF-β treatment caused an activation of NF-κB, and heat treatment significantly attenuated TGF-β-indueced NF-κB activation in HT29 cells. Conclusions: Our results suggest that the heat treatment could suppress TGF-β-induced EMT via the inhibition of NF-κB, supporting its potential as a treatment for cancer metastasis. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2414. doi:1538-7445.AM2012-2414

Abstract 967: N-Myc interactor, a novel regulator of EMT

Abstract Dissemination of tumor cells and subsequent colonization at distant sites is the most lethal event in cancer progression. The epithelial-mesenchymal transition (EMT) has recently been recognized as a foremost phenomenon underlying such events. Because of the importance of EMT, it is vital to understand what triggers it, as well as the mechanisms by which it is regulated. We have shown that N-myc interactor (NMI) plays a role in restricting malignant activities of cancerous cell lines in vivo and in vitro. This study describes a novel function of NMI in reducing the mesenchymal phenotype of breast cancer cell lines. Constitutive expression of NMI in the mesenchymal cell line MDA-MB-435, showed remarkable morphologic transition towards an epithelial appearance, accompanied by reduction or loss of several mesenchymal markers such as TWIST, MMP2, SNAI2 and ZEB1 and gain of epithelial markers such as E-cadherin and Keratin 18. Conversely, silencing NMI from immortalized breast epithelial line MCF10A, renders the cells more mesenchymal in appearance. Studies using a variety of additional cell lines consistently revealed that silencing of NMI expression coincided with increased expression of both ZEB1 and SNAI2, while NMI overexpression brought about decreased expression of ZEB1 and SNAI2. Assessment of NMI in breast cancer specimens revealed a significant loss of NMI transcript with increasing grade of breast cancer. Thus, overall, our data strongly suggests that loss of NMI may be a key event allowing increased expression of EMT-inducing transcription factors that drive EMT-dependent malignant progression. Acknowledgement: We acknowledge grant support from the NCI: 1R01CA140472 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 967. doi:10.1158/1538-7445.AM2011-967