Unraveling the Role of Epithelial-Mesenchymal Transition in Adenoid Cystic Carcinoma of the Salivary Glands: A Comprehensive Review

Salivary adenoid cystic carcinoma (SACC) is considered a challenging malignancy; it is characterized by a slow-growing nature, yet a high risk of recurrence and distant metastasis, presenting significant hurdles in its treatment and management. At present, there are no approved targeted agents available for the management of SACC and systemic chemotherapy protocols that have demonstrated efficacy remain to be elucidated. Epithelial-mesenchymal transition (EMT) is a complex process that is closely associated with tumor progression and metastasis, enabling epithelial cells to acquire mesenchymal properties, including increased mobility and invasiveness. Several molecular signaling pathways have been implicated in the regulation of EMT in SACC, and understanding these mechanisms is crucial to identifying new therapeutic targets and developing more effective treatment approaches. This manuscript aims to provide a comprehensive overview of the latest research on the role of EMT in SACC, including the molecular pathways and biomarkers involved in EMT regulation. By highlighting the most recent findings, this review offers insights into potential new therapeutic strategies that could improve the management of SACC patients, especially those with recurrent or metastatic disease.

Isolation of Vaginal Epithelial Cells: In Preparation of Autologous Vaginal Tissue Lining for Congenital Absence of Vagina Patients

Infertility is a condition affecting women who are born with an underdeveloped or absent vagina, a birth defect known as congenital absence of the vagina. It is a rare disorder where the development of the Mullerian duct is obstructed by unidentified causes. The case is seldom reported due to the low prevalence and sparse epidemiology studies worldwide. A potential solution for the disorder is neovaginal creation with in vitro cultured vaginal mucosa. Limited studies have reported its application, but none are reproducible or specific regarding the established processes for acquiring vaginal epithelial cells from vaginal biopsies. These research gaps were adequately answered with an epidemiology study of inpatient details in Hospital Canselor Tuanku Muhriz, Malaysia, established methods and outcomes of vaginal tissue processing and isolation, and characterization of vaginal epithelial cells using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and immunofluorescence assays. The reported evidence and speculation that the disorder arises because of a cellular transition event between epithelial and mesenchymal cells during the development of the Mullerian duct could be key in the creation of neovaginas using established culture procedures to improve surgical results and restore fertility.

Human Adipose-Derived Mesenchymal Stem Cells Ameliorate Elastase-Induced Emphysema in Mice by Mesenchymal-Epithelial Transition

Purpose

Chronic obstructive pulmonary disease (COPD) is a worldwide problem because of its high prevalence and mortality. However, there is no fundamental treatment to ameliorate their pathological change in COPD lung. Recently, adipose-derived mesenchymal stem cells (ADSCs) have attracted attention in the field of regenerative medicine to repair damaged organs. Moreover, their utility in treating respiratory diseases has been reported in some animal models. However, the detailed mechanism by which ADSCs improve chronic respiratory diseases, including COPD, remains to be elucidated. We examined whether human ADSCs (hADSCs) ameliorated elastase-induced emphysema and whether hADSCs differentiated into alveolar epithelial cells in a murine model of COPD.

Methods

Female SCID-beige mice (6 weeks old) were divided into the following four groups according to whether they received an intratracheal injection of phosphate-buffered saline or porcine pancreatic elastase, and whether they received an intravenous injection of saline or hADSCs 3 days after intratracheal injection; Control group, hADSC group, Elastase group, and Elastase-hADSC group. We evaluated the lung function, assessed histological changes, and compared gene expression between hADSCs isolated from the lung of Elastase-hADSC group and naïve hADSCs 28 days after saline or elastase administration.

Results

hADSCs improved the pathogenesis of COPD, including the mean linear intercept and forced expiratory volume, in an elastase-induced emphysema model in mice. Furthermore, hADSCs were observed in the lungs of elastase-treated mice at 25 days after administration. These cells expressed genes related to mesenchymal–epithelial transition and surface markers of alveolar epithelial cells, such as TTF-1, β-catenin, and E-cadherin.

Conclusion

hADSCs have the potential to improve the pathogenesis of COPD by differentiating into alveolar epithelial cells by mesenchymal–epithelial transition.

Phenotypic Heterogeneity of Triple-Negative Breast Cancer Mediated by Epithelial-Mesenchymal Plasticity

Triple-negative breast cancer (TNBC) is a subtype of breast carcinoma known for its unusually aggressive behavior and poor clinical outcome. Besides the lack of molecular targets for therapy and profound intratumoral heterogeneity, the relatively quick overt metastatic spread remains a major obstacle in effective clinical management. The metastatic colonization of distant sites by primary tumor cells is affected by the microenvironment, epigenetic state of particular subclones, and numerous other factors. One of the most prominent processes contributing to the intratumoral heterogeneity is an epithelial-mesenchymal transition (EMT), an evolutionarily conserved developmental program frequently hijacked by tumor cells, strengthening their motile and invasive features. In response to various intrinsic and extrinsic stimuli, malignant cells can revert the EMT state through the mesenchymal-epithelial transition (MET), a process that is believed to be critical for the establishment of macrometastasis at secondary sites. Notably, cancer cells rarely undergo complete EMT and rather exist in a continuum of E/M intermediate states, preserving high levels of plasticity, as demonstrated in primary tumors and, ultimately, in circulating tumor cells, representing a simplified element of the metastatic cascade. In this review, we focus on cellular drivers underlying EMT/MET phenotypic plasticity and its detrimental consequences in the context of TNBC cancer.

Mesenchymal-Epithelial Transition in Fibroblasts of Human Normal Lungs and Interstitial Lung Diseases

In passages above ten and growing very actively, we observed that some human lung fibroblasts cultured under standard conditions were transformed into a lineage of epithelial-like cells (ELC). To systematically evaluate the possible mesenchymal–epithelial transition (MET) occurrence, fibroblasts were obtained from normal lungs and also from lungs affected by idiopathic interstitial diseases. When an unusual epithelial-like phenotypic change was observed, cultured cells were characterized by confocal immunofluorescence microscopy, immunoblotting, immunocytochemistry, cytofluorometry, gelatin zymography, RT-qPCR, and hybridization in a whole-transcript human microarray. Additionally, microvesicles fraction (MVs) from ELC and fibroblasts were used to induce MET, while the microRNAs (miRNAs) contained in the MVs were identified. Pattern-gene expression of the original fibroblasts and the derived ELC revealed profound changes, upregulating characteristic epithelial-cell genes and downregulating mesenchymal genes, with a marked increase of E-cadherin, cytokeratin, and ZO-1, and the loss of expression of α-SMA, collagen type I, and Thy-1 cell surface antigen (CD90). Fibroblasts, exposed to culture media or MVs from the ELC, acquired ELC phenotype. The miRNAs in MVs shown six expressed exclusively in fibroblasts, and three only in ELC; moreover, twelve miRNAs were differentially expressed between fibroblasts and ELC, all of them but one was overexpressed in fibroblasts. These findings suggest that the MET-like process can occur in human lung fibroblasts, either from normal or diseased lungs. However, the biological implication is unclear.

Picturing Breast Cancer Brain Metastasis Development to Unravel Molecular Players and Cellular Crosstalk

Simple Summary

Breast cancer is a devastating disorder affecting millions of women worldwide. With improved therapeutics for the primary tumor, the appearance of metastasis has been increasing. Breast cancer frequently metastasizes to the brain, constituting a major hurdle without cure and with a poor survival. It is imperative to better understand the mechanisms involved in malignant cell transposition of the brain microvasculature and parenchymal colonization by deciphering the alterations occurring in the tumor and microvascular cells, as well as the occurrence of intercellular communication during the process. We aimed to profile the process of the formation of breast cancer brain metastasis and the timeline of events governing it. We used a specific mouse model of the disease to perform extensive microscopic analyses. We identified phenotypic changes and the activation of relevant molecular players in tumorigenesis, together with vascular alterations, and the occurrence of crosstalk. Our findings unravel putative therapeutic targets to tackle breast cancer brain metastasis.

Abstract

With breast cancer (BC) therapy improvements, the appearance of brain metastases has been increasing, representing a life-threatening condition. Brain metastasis formation involves BC cell (BCC) extravasation across the blood–brain barrier (BBB) and brain colonization by unclear mechanisms. We aimed to disclose the actors involved in BC brain metastasis formation, focusing on BCCs’ phenotype, growth factor expression, and signaling pathway activation, correlating with BBB alterations and intercellular communication. Hippocampi of female mice inoculated with 4T1 BCCs were examined over time by hematoxylin-eosin, immunohistochemistry and immunofluorescence. Well-established metastases were observed at seven days, increasing thereafter. BCCs entering brain parenchyma presented mesenchymal, migratory, and proliferative features; however, with time, they increasingly expressed epithelial markers, reflecting a mesenchymal–epithelial transition. BCCs also expressed platelet-derived growth factor-B, β₄ integrin, and focal adhesion kinase, suggesting autocrine and/or paracrine regulation with adhesion signaling activation, while balance between Rac1 and RhoA was associated with the motility status. Intercellular communication via gap junctions was clear among BCCs, and between BCCs and endothelial cells. Thrombin accumulation, junctional protein impairment, and vesicular proteins increase reflect BBB alterations related with extravasation. Expression of plasmalemma vesicle-associated protein was increased in BCCs, along with augmented vascularization, whereas pericyte contraction indicated mural cells’ activation. Our results provide further understanding of BC brain metastasis formation, disclosing potential therapeutic targets.

Epithelial-mesenchymal plasticity: emerging parallels between tissue morphogenesis and cancer metastasis

Many cells possess epithelial–mesenchymal plasticity (EMP), which allows them to shift reversibly between adherent, static and more detached, migratory states. These changes in cell behaviour are driven by the programmes of epithelial–mesenchymal transition (EMT) and mesenchymal–epithelial transition (MET), both of which play vital roles during normal development and tissue homeostasis. However, the aberrant activation of these processes can also drive distinct stages of cancer progression, including tumour invasiveness, cell dissemination and metastatic colonization and outgrowth. This review examines emerging common themes underlying EMP during tissue morphogenesis and malignant progression, such as the context dependence of EMT transcription factors, a central role for partial EMTs and the nonlinear relationship between EMT and MET.

This article is part of a discussion meeting issue ‘Contemporary morphogenesis'.

Ovol2 induces mesenchymal-epithelial transition via targeting ZEB1 in osteosarcoma

Purpose

Osteosarcoma (OS) is the most common type of primary solid bone tumor. Ovo-like zinc finger 2 (Ovol2), a zinc finger transcription factor, is a mesenchymal–epithelial transition (MET) driver that induces miR-200 expression in prostate cancer, breast cancer, and hepatocellular carcinoma. However, little is known about the expression and function of MET in sarcomas, including OS. This study investigated the expression and clinicopathological significance of Ovol2 and its effect on MET in OS.

Patients and methods

The Ovol2 expression in the tumor samples from patients with OS was examined using immunohistochemistry (IHC). We then upregulated the Ovol2 expression in MG-63 and SW1353 cells, detected the expression of MET-associated proteins, and observed the effects of Ovol2 on OS cell proliferation, migration, and cytoskeleton reorganization using Cell Counting Kit-8, transwell invasion, and phalloidin dyeing assays, respectively. The correlation between zinc finger E-box-binding homeobox 1 (ZEB1) and Ovol2 was assessed using the luciferase gene reporter assay in the MG-63 and SW1353 cells and IHC in the human OS tissue samples.

Results

The Ovol2 protein overexpression was related to the clinical grade (P=0.02) and the recurrence and metastasis (P=0.02) of OS. Results of the in vitro experiments showed that Ovol2 overexpression can suppress cell migration and invasion and can regulate the expression levels of MET-associated proteins. Ovol2 suppresses ZEB1 expression by binding to the ZEB1 promoter. Ovol2 is concomitant with a reduced IHC expression of ZEB1 in human OS tissues.

Conclusion

Ovol2 expression is associated with MET in OS cells and suppresses ZEB1 expression and OS progression.

The Mesenchymal-Epithelial and Epithelial-Mesenchymal Cellular Plasticity of Liver Metastases with Digestive Origin

BACKGROUND

Few data are available regarding the epithelial to mesenchymal transition (EMT) /mesenchymal to epitheilal transition (MET) in the liver metastasis of digestive cancers. The aim of this study was to establish EMT/MET metastatic tumor cell plasticity according to the histological growth pattern of liver metastases.

MATERIALS AND METHODS

Biopsies from 25 patients with liver metastasis (desmoplastic, replacement and pushing type) were evaluated. Double immunostaining of E-cadherin/vimentin, keratin 8,18/vimentin and E-cadherin/ keratin 8,18 were performed.

RESULTS

The following cell types were noted: epithelial, mesenchymal, non-differentiated and differentiated hybrid mesenchymal/ epithelial and non-hybrid phenotype. All cases had mesenchymal/ epithelial phenotype cells. A significant correlation was found between the non-differentiated hybrid mesenchymal/ epithelial phenotype metastatic cells and histological growth pattern for gastric and colorectal cancer.

CONCLUSION

A MET-targeting strategy, in conjunction with conventional chemotherapy, may be useful for the treatment of liver metastases.

Lipid Supplement in the Cultural Condition Facilitates the Porcine iPSC Derivation through cAMP/PKA/CREB Signal Pathway. Int J Mol Sci. 2018;19:pii: E509. [PMID: 29419748 PMCID: PMC5855731 DOI: 10.3390/ijms19020509]

Large numbers of lipids exist in the porcine oocytes and early embryos and have the positive effects on their development, suggesting that the lipids may play an important role in pluripotency establishment and maintenance in pigs. However, the effects of lipids and their metabolites, such as fatty acids on reprogramming and the pluripotency gene expression of porcine-induced pluripotent stem cells (iPSCs), are unclear. Here, we generated the porcine iPSCs that resemble the mouse embryonic stem cells (ESCs) under lipid and fatty-acid-enriched cultural conditions (supplement of AlbuMAX). These porcine iPSCs show positive for the ESCs pluripotency markers and have the differentiation abilities to all three germ layers, and importantly, have the capability of aggregation into the inner cell mass (ICM) of porcine blastocysts. We further confirmed that lipid and fatty acid enriched condition can promote the cell proliferation and improve reprogramming efficiency by elevating cAMP levels. Interestingly, this lipids supplement promotes mesenchymal–epithelial transition (MET) through the cAMP/PKA/CREB signal pathway and upregulates the E-cadherin expression during porcine somatic cell reprogramming. The lipids supplement also makes a contribution to lipid droplets accumulation in the porcine iPSCs that resemble porcine preimplantation embryos. These findings may facilitate understanding of the lipid metabolism in porcine iPSCs and lay the foundation of bona fide porcine embryonic stem cell derivation.

Human endometrial stem cells: High-yield isolation and characterization

BACKGROUND

Menstrual blood is only recently and still poorly studied, but it is an abundant and noninvasive source of highly proliferative mesenchymal stromal cells (MSCs). However, no appropriate isolation method has been reported due to its high viscosity and high content of clots and desquamated epithelium.

METHODS

We studied three different isolation approaches and their combinations: ammonium-containing lysing buffer, distilled water and gradient-density centrifugation. We tested the proliferative capacity, morphology, surface markers and pluripotency of the resulting cells.

RESULTS

Our isolation method yields up to four million nucleated cells per milliliter of initial blood, of which about 0.2-0.3% are colony-forming cells expressing standard mesenchymal markers CD90, CD105 and CD73, but not expressing CD45, CD34, CD117, CD133 or HLA-G. The cells have high proliferative potential (doubling in 26 h) and the ability to differentiate into adipocytes and osteocytes. Early endometrial MSCs (eMSCs) express epithelial marker cytokeratin 7 (CK7). CK7 is easily induced in later passages in a prohepatic environment. We show for the first time that a satisfactory and stable yield of eMSCs is observed throughout the whole menstrual period (5 consecutive days) of a healthy woman.

DISCUSSION

The new cost/yield adequate method allows isolation from menstrual blood a relatively homogenous pool of highly proliferative MSCs, which seem to be the best candidates for internal organ therapy due to their proepithelial background (early expression of CK7 and its easy induction in later passages) and for mass cryobanking due to their high yield and availability.

Expression of Ovol2 is related to epithelial characteristics and shows a favorable clinical outcome in hepatocellular carcinoma

Metastasis involves epithelial–mesenchymal transition (EMT) and mesenchymal–epithelial transition. Ovol2 belongs to the Ovo-like family (Ovol) of evolutionarily conserved zinc-finger transcription factors that regulate gene expression in various differentiation processes. Recent studies have demonstrated that Ovols affect mesenchymal–epithelial transition by inducing the expression of miR-200 in a range of human cancers. Downregulated Ovol2 expression is involved in the invasion and metastasis of breast and prostate cancers, but little is known about its expression and prognostic value in other cancers, including hepatocellular carcinoma (HCC). This study was designed to explore the clinical and prognostic significance of Ovol2 in patients with HCC. The expression of Ovol2 in tumor samples from patients with HCC and HCC cell lines was examined using Western blotting, real-time polymerase chain reaction, and immunohistochemistry. The expression levels of EMT-related markers, including E-cadherin, N-cadherin, and vimentin, were detected in relation to Ovol2 expression. The prognostic significance of Ovol2 in patients with HCC was statistically analyzed by Kaplan–Meier and Cox regression analyses. Ovol2 expression was significantly lower in HCC tissues than in adjacent noncancerous tissues. Low expression of Ovol2 was detected in HCC tissues with poor histological differentiation, microvascular invasion, and cirrhosis. A significant relationship was observed between Ovol2 and EMT marker expression levels. Kaplan–Meier analysis showed that overall survival was significantly worse in patients with HCC with low Ovol2 expression, indicating that Ovol2 deletion was an independent predictor of unfavorable prognosis in patients with HCC. Elevated Ovol2 expression may suppress HCC cell invasion and metastasis via restricting EMT.

Epithelial plasticity in prostate cancer: principles and clinical perspectives

Over the past decade, the capacity of cancer cells to oscillate between epithelial and mesenchymal phenotypes, termed epithelial plasticity (EP), has been demonstrated to play a critical role in metastasis. This phenomenon may be particularly important for prostate cancer (PC) progression, since recent studies have revealed interplay between EP and signaling by the androgen receptor (AR) oncoprotein. Moreover, EP appears to play a role in dictating the response to therapies for metastatic PC. This review will evaluate preclinical and clinical evidence for the relevance of EP in PC progression and consider the potential of targeting and measuring EP as a means to treat and manage lethal forms of the disease.

Ethanol alters gene expression and cell organization during optic vesicle evagination

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Ethanol alters eye morphogenesis at early stages of embryogenesis.

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The expression patterns of some genes important for eye morphogenesis are perturbed.

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Ethanol is related to alterations in cell morphology.

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Ethanol interferes with the optic vesicles evagination.

Ethanol has been described as a teratogen in vertebrate development. During early stages of brain formation, ethanol affects the evagination of the optic vesicles, resulting in synophthalmia or cyclopia, phenotypes where the optic vesicles partially or totally fuse. The mechanisms by which ethanol affects the morphogenesis of the optic vesicles are however largely unknown. In this study we make use of in situ hybridization, electron microscopy and immunohistochemistry to show that ethanol has profound effects on cell organization and gene expression during the evagination of the optic vesicles. Exposure to ethanol during early eye development alters the expression patterns of some genes known to be important for eye morphogenesis, such as rx3/1 and six3a. Furthermore, exposure to ethanol interferes with the acquisition of neuroepithelial features by the eye field cells, which is clear at ultrastructual level. Indeed, ethanol disrupts the acquisition of fusiform cellular shapes within the eye field. In addition, tight junctions do not form and retinal progenitors do not properly polarize, as suggested by the mis-localization and down-regulation of zo1. We also show that the ethanol-induced cyclopic phenotype is significantly different to that observed in cyclopic mutants, suggesting a complex effect of ethanol on a variety of targets.

Our results show that ethanol not only disrupts the expression pattern of genes involved in retinal morphogenesis, such as rx3 and rx1, but also disrupts the changes in cell polarity that normally occur during eye field splitting. Thus, ethylic teratology seems to be related not only to modifications in gene expression and cell death but also to alterations in cell morphology.

Epithelial-mesenchymal transition in ovarian carcinoma

Ovarian cancer is the most lethal gynecologic malignancy, with the majority of patients dying within 5 years of diagnosis. This poor survival of patients diagnosed with this malignancy is attributed to diagnosis at advanced stage, when the tumor has metastasized, and to chemotherapy resistance, either primary or developing along tumor progression. However, ovarian carcinomas, constituting the vast majority of ovarian cancers, additionally have unique biology, one aspect of which is the ability to co-express epithelial and mesenchymal determinants. epithelial–mesenchymal transition (EMT), a physiological process by which mesenchymal cells are formed and migrate to target organs during embryogenesis, is involved in cancer cell invasion and metastasis. However, these changes do not fully occur in ovarian carcinoma, and are even reversed in tumor cells present in malignant peritoneal and pleural effusions. This review summarizes current knowledge in this area, including the characteristics of EMT related to adhesion, transcriptional regulation and chemoresistance, and their clinical relevance, as well as the recently observed regulation of EMT by microRNA.

Emerging role of brain metastases in the prognosis of breast cancer patients

Cancer starts with one rogue cell. Through mutations and genomic alterations, the cell acquires specific and stem cell-like characteristics necessary for invasion of a distant organ and ultimately metastasis. Metastatic brain cancer is a particularly formidable disease because of its poor prognosis and the highly resistant nature of the tumor to chemotherapy. Although several types of primary tumors have a tendency to metastasize to the brain, the incidence of brain metastases has increased dramatically in some subsets of breast cancer patients. Several conventional treatments are available, but success is limited and often short-lived. Given that no standard treatment options exist, there is a significant need to investigate the biology of these clinically recalcitrant tumors.