Epithelial-mesenchymal Transition Program Research Articles

A Novel circRNA hsa_circRNA_002178 as a Diagnostic Marker in Hepatocellular Carcinoma Enhances Cell Proliferation, Invasion, and Tumor Growth by Stabilizing SRSF1 Expression.

Background Previous research studies have shown that the elevation of circular RNA (circRNA), hsa_circRNA_002178, was associated with the poor prognosis of breast cancer and colorectal cancer, while its molecular mechanisms underlying the effects on hepatocellular carcinoma (HCC) are still elusive. Methods The microarray dataset GSE97332 was obtained from the Gene Expression Omnibus (GEO) database and calculated by using the GEO2R tool to identify differentially expressed circRNAs. Differentially expressed hsa_circRNA_002178, in 7 HCC tissue samples and paracancerous tissues, as well as in HCC cell lines and normal hepatocytes, was checked by RT-qPCR. Cell proliferation, invasion, migration, and epithelial-to-mesenchymal transition (EMT)-related proteins were tested in hsa_circRNA_002178-overexpressed or hsa_circRNA_002178-knocked down HCC cells. Subsequently, we identified whether hsa_circRNA_002178 binds to serine- and arginine-rich splicing factor 1 (SRSF1) and then analyzed their function in regulating HCC cell behavior. The effect on HCC cell xenograft tumor growth was observed by the knockdown of hsa_circRNA_002178 in vivo. Results GEO2R-based analysis displayed that hsa_circRNA_002178 was upregulated in HCC tissues. Overexpression or knockdown of hsa_circRNA_002178 encouraged or impeded HCC cell proliferation, migration, invasion, and EMT program. Mechanically, hsa_circRNA_002178 bound to SRSF1 3′-untranslated region (UTR) and stabilized its expression. SRSF1 weakening eliminated the effects of pcDNA-hsa_circRNA_002178 on cell malignant behavior. Finally, the knockdown of hsa_circRNA_002178 was confirmed to prevent xenograft tumor growth. Conclusions hsa_circRNA_002178 overexpression encouraged the stability of SRSF1 mRNA expression, and it may serve as an upstream factor of SRSF1 for the diagnosis of HCC.

Tbx18 Orchestrates Cytostructural Transdifferentiation of Cardiomyocytes to Pacemaker Cells by Recruiting the Epithelial-Mesenchymal Transition Program.

Previously, we reported that heterologous expression of an embryonic transcription factor, Tbx18, reprograms ventricular cardiomyocytes into induced pacemaker cells (Tbx18-iPMs), though the key pathways are unknown. Here, we have used a tandem mass tag proteomic approach to characterize the impact of Tbx18 on neonatal rat ventricular myocytes. Tbx18 expression triggered vast proteome remodeling. Tbx18-iPMs exhibited increased expression of known pacemaker ion channels, including Hcn4 and Cx45 as well as upregulation of the mechanosensitive ion channels Piezo1, Trpp2 (PKD2), and TrpM7. Metabolic pathways were broadly downregulated, as were ion channels associated with ventricular excitation-contraction coupling. Tbx18-iPMs also exhibited extensive intracellular cytoskeletal and extracellular matrix remodeling, including 96 differentially expressed proteins associated with the epithelial-to-mesenchymal transition (EMT). RNAseq extended coverage of low abundance transcription factors, revealing upregulation of EMT-inducing Snai1, Snai2, Twist1, Twist2, and Zeb2. Finally, network diffusion mapping of >200 transcriptional regulators indicates EMT and heart development factors occupy adjacent network neighborhoods downstream of Tbx18 but upstream of metabolic control factors. In conclusion, transdifferentiation of cardiac myocytes into pacemaker cells entails massive electrogenic, metabolic, and cytostructural remodeling. Structural changes exhibit hallmarks of the EMT. The results aid ongoing efforts to maximize the yield and phenotypic stability of engineered biological pacemakers.

A Hybrid Epithelial to Mesenchymal Transition in Ex Vivo Cutaneous Squamous Cell Carcinoma Tissues.

While most cases of cutaneous squamous cell carcinoma (cSCC) are benign, invasive cSCC is associated with higher mortality and is often more difficult to treat. As such, understanding the factors that influence the progression of cSCC are important. Aggressive cancers metastasize through a series of evolutionary changes, collectively called the epithelial-to-mesenchymal transition (EMT). During EMT, epithelial cells transition to a highly mobile mesenchymal cell type with metastatic capacities. While changes in expression of TGF-β, ZEB1, SNAI1, MMPs, vimentin, and E-cadherin are hallmarks of an EMT process occurring within cancer cells, including cSCC cells, EMT within tissues is not an “all or none” process. Using patient-derived cSCC and adjacent normal tissues, we show that cells within individual cSCC tumors are undergoing a hybrid EMT process, where there is variation in expression of EMT markers by cells within a tumor mass that may be facilitating invasion. Interestingly, cells along the outer edges of a tumor mass exhibit a more mesenchymal phenotype, with reduced E-cadherin, β-catenin, and cytokeratin expression and increased vimentin expression. Conversely, cells in the center of a tumor mass retain a higher expression of the epithelial markers E-cadherin and cytokeratin and little to no expression of vimentin, a mesenchymal marker. We also detected inverse expression changes in the miR-200 family and the EMT-associated transcription factors ZEB1 and SNAI1, suggesting that cSCC EMT dynamics are regulated in a miRNA-dependent manner. These novel findings in cSCC tumors provide evidence of phenotypic plasticity of the EMT process occurring within patient tissues, and extend the characterization of a hybrid EMT program occurring within a tumor mass. This hybrid EMT program may be promoting both survival and invasiveness of the tumors. A better understanding of this hybrid EMT process may influence therapeutic strategies in more invasive disease.

Triple-negative breast cancer metastasis involves complex epithelial-mesenchymal transition dynamics and requires vimentin.

Triple-negative breast cancer (TNBC) is an aggressive subtype associated with early metastatic recurrence and worse patient outcomes. TNBC tumors express molecular markers of the epithelial-mesenchymal transition (EMT), but its requirement during spontaneous TNBC metastasis in vivo remains incompletely understood. We demonstrated that spontaneous TNBC tumors from a genetically engineered mouse model (GEMM), multiple patient-derived xenografts, and archival patient samples exhibited large populations in vivo of hybrid E/M cells that lead invasion ex vivo while expressing both epithelial and mesenchymal characteristics. The mesenchymal marker vimentin promoted invasion and repressed metastatic outgrowth. We next tested the requirement for five EMT transcription factors and observed distinct patterns of utilization during invasion and colony formation. These differences suggested a sequential activation of multiple EMT molecular programs during the metastatic cascade. Consistent with this model, our longitudinal single-cell RNA analysis detected three different EMT-related molecular patterns. We observed cancer cells progressing from epithelial to hybrid E/M and strongly mesenchymal patterns during invasion and from epithelial to a hybrid E/M pattern during colony formation. We next investigated the relative epithelial versus mesenchymal state of cancer cells in both GEMM and patient metastases. In both contexts, we observed heterogeneity between and within metastases in the same individual. We observed a complex spectrum of epithelial, hybrid E/M, and mesenchymal cell states within metastases, suggesting that there are multiple successful molecular strategies for distant organ colonization. Together, our results demonstrate an important and complex role for EMT programs during TNBC metastasis.

PI3Kδ activity controls plasticity and discriminates between EMT and stemness based on distinct TGFβ signaling

The stem cells involved in formation of the complex human body are epithelial cells that undergo apicobasal polarization and form a hollow lumen. Epithelial plasticity manifests as epithelial to mesenchymal transition (EMT), a process by which epithelial cells switch their polarity and epithelial features to adopt a mesenchymal phenotype. The connection between the EMT program and acquisition of stemness is now supported by a substantial number of reports, although what discriminates these two processes remains largely elusive. In this study, based on 3D organoid culture of hepatocellular carcinoma (HCC)-derived cell lines and AAV8-based protein overexpression in the mouse liver, we show that activity modulation of isoform δ of phosphoinositide 3-kinase (PI3Kδ) controls differentiation and discriminates between stemness and EMT by regulating the transforming growth factor β (TGFβ) signaling. This study provides an important tool to control epithelial cell fate and represents a step forward in understanding the development of aggressive carcinoma.

Repositioning of Old Drugs for Novel Cancer Therapies: Continuous Therapeutic Perfusion of Aspirin and Oseltamivir Phosphate with Gemcitabine Treatment Disables Tumor Progression, Chemoresistance, and Metastases.

Simple SummaryRepositioning old drugs in combination with clinical standard chemotherapeutics opens a promising clinical treatment approach for patients with pancreatic cancer. This report presents a therapeutic repositioning of continuous perfusion of aspirin and oseltamivir phosphate in combination with gemcitabine treatment as an effective treatment option for pancreatic cancer. The data suggest that repositioning these drugs with continuous perfusion with gemcitabine disables chemoresistance, tumor progression, EMT program, cancer stem cells, and metastases in a preclinical mouse model of human pancreatic cancer. These promising results warrant additional investigation to assess the potential of translating into the clinical setting to improve the cancer patient prognosis for an otherwise fatal disease.Metastatic pancreatic cancer has an invariably fatal outcome, with an estimated median progression-free survival of approximately six months employing our best combination chemotherapeutic regimens. Once drug resistance develops, manifested by increased primary tumor size and new and growing metastases, patients often die rapidly from their disease. Emerging evidence indicates that chemotherapy may contribute to the development of drug resistance through the upregulation of epithelial–mesenchymal transition (EMT) pathways and subsequent cancer stem cell (CSC) enrichment. Neuraminidase-1 (Neu-1) regulates the activation of several receptor tyrosine kinases implicated in EMT induction, angiogenesis, and cellular proliferation. Here, continuous therapeutic targeting of Neu-1 using parenteral perfusion of oseltamivir phosphate (OP) and aspirin (ASA) with gemcitabine (GEM) treatment significantly disrupts tumor progression, critical compensatory signaling mechanisms, EMT program, CSC, and metastases in a preclinical mouse model of human pancreatic cancer. ASA- and OP-treated xenotumors significantly inhibited the metastatic potential when transferred into animals.

Involvement of Met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide.

Involvement of Met receptor pathway in aggressive behavior of colorectal cancer cells induced by parathyroid hormone-related peptide.

2,3,5,6-Tetramethylpyrazine Targets Epithelial-Mesenchymal Transition by Abrogating Manganese Superoxide Dismutase Expression and TGFβ-Driven Signaling Cascades in Colon Cancer Cells.

Epithelial-mesenchymal transition (EMT) is a crucial process in which the polarized epithelial cells acquire the properties of mesenchymal cells and gain invasive properties. We have previously demonstrated that manganese superoxide dismutase (MnSOD) can regulate the EMT phenotype by modulating the intracellular reactive oxygen species. In this report, we have demonstrated the EMT-suppressive effects of 2,3,5,6-Tetramethylpyrazine (TMP, an alkaloid isolated from Chuanxiong) in colon cancer cells. TMP suppressed the expression of MnSOD, fibronectin, vimentin, MMP-9, and N-cadherin with a parallel elevation of occludin and E-cadherin in unstimulated and TGFβ-stimulated cells. Functionally, TMP treatment reduced the proliferation, migration, and invasion of colon cancer cells. TMP treatment also modulated constitutive activated as well as TGFβ-stimulated PI3K/Akt/mTOR, Wnt/GSK3/β-catenin, and MAPK signaling pathways. TMP also inhibited the EMT program in the colon cancer cells-transfected with pcDNA3-MnSOD through modulation of MnSOD, EMT-related proteins, and oncogenic pathways. Overall, these data indicated that TMP may inhibit the EMT program through MnSOD-mediated abrogation of multiple signaling events in colon cancer cells.

The Role of MicroRNA in the Regulation of Tumor Epithelial-Mesenchymal Transition.

Consistently, the high metastasis of cancer cells is the bottleneck in the process of tumor treatment. In this process of metastasis, a pivotal role is executed by epithelial–mesenchymal transition (EMT). The epithelial-to-mesenchymal transformation was first proposed to occur during embryonic development. Later, its important role in explaining embryonic developmental processes was widely reported. Recently, EMT and its intermediate state were also identified as crucial drivers in tumor progression with the gradual deepening of research. To gain insights into the potential mechanism, increasing attention has been focused on the EMT-related transcription factors. Correspondingly, miRNAs target transcription factors to control the EMT process of tumor cells in different types of cancers, while there are still many exciting and challenging questions about the phenomenon of microRNA regulation of cancer EMT. We describe the relevant mechanisms of miRNAs regulating EMT, and trace the regulatory roles and functions of major EMT-related transcription factors, including Snail, Twist, zinc finger E-box-binding homeobox (ZEB), and other families. In addition, on the basis of the complex regulatory network, we hope that the exploration of the regulatory relationship of non-transcription factors will provide a better understanding of EMT and cancer metastasis. The identification of the mechanism leading to the activation of EMT programs during diverse disease processes also provides a new protocol for the plasticity of distinct cellular phenotypes and possible therapeutic interventions. Here, we summarize the recent progress in this direction, with a promising path for further insight into this fast-moving field.

Abstract 1543: Regulatory role of miR-410 in prostate cancer

Abstract Prostate cancer (PCa), a leading cause of male cancer related mortality, is dependent upon androgens acting via androgen receptor (AR) signaling. Androgen targeted therapies are often used as the first line of treatment for prostate cancer that are effective initially. However, PCa eventually progresses to castration-resistant stage that has limited treatment options. Castration-resistant prostate cancer (CRPC) is treated by second generation of AR pathway inhibitors such as Enzalutamide and Abiraterone. Resistance to these agents develop owing to various mechanisms such as evolution to androgen-independent neuroendocrine prostate cancer (NEPC). In this study, we examined the potential role of miR-410 in different stages of prostate cancer. Analyses of miR-410 in PCa clinical samples and patient-derived xenograft (PDX) models showed that miR-410 is frequently upregulated in PCa. Its expression was further increased in CRPC cases with neuroendocrine differentiation (NED). We examined the functional role of miR-410 by stably expressing miR-410 in androgen dependent and androgen independent cell lines. Our data suggests a context dependent role of miR-410 in prostate cancer cell lines. In androgen independent cell line, miR-410 plays an oncogenic role by impacting epithelial to mesenchymal transition (EMT) via directly targeting SNAIL. Also, it was found to increase the expression of neuronal genes such as Synaptophysin and neural transcription factor BRN2. However, in androgen dependent cell line, miR-410 was found to target PTEN. In conclusion, our data suggests that miR-410 play an important regulatory role in prostate cancer with effects on EMT and neuronal differentiation programs. Citation Format: Amritha Sreekumar, Nikhil Patel, Sharanjot Saini. Regulatory role of miR-410 in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1543.

Abstract LB022: A hybrid epithelial to mesenchymal transition in ex-vivo cutaneous squamous cell carcinoma tissues

Abstract While most cases of cutaneous squamous cell carcinoma (cSCC) are benign, invasive cSCC is associated with higher mortality and is often more difficult to treat. As such, understanding the factors that influence the progression of cSCC are important. Aggressive cancers metastasize through a series of evolutionary changes, collectively called the epithelial-to-mesenchymal transition (EMT). During EMT, epithelial cells transition to a highly mobile mesenchymal cell type with metastatic capacities. While changes in expression of TGF-β, vimentin, and E-cadherin are hallmarks, EMT is not an “all or none” process. Using patient-derived cSCC and adjacent normal tissues (ANT), we observed a significant increase in mRNA expression of TGF-β (p<0.05), TGF-βR2 (p<0.001), and E-cadherin (p<0.005) in cSCC tissues by qPCR. Immunoblots performed on homogenized tissues yielded significant and parallel increases in protein expression of TGF-β (p<0.05) and E-cadherin (p<0.05). We also observed increased expression of the EMT-associated transcription factors Zeb1 and Snai1 in cSCC tissue sections using immunohistochemistry. Interestingly, we observed a significant increase in expression of vimentin (p<0.01) by immunoblot and differential expression of four oncogenic and EMT-associated miRNAs; miR-31 expression was significantly higher in cSCC tissues (p<0.001), while we observed a significant decrease in expression of miR-34a (p<0.05), miR-200b, and miR-200c in cSCC tissues. Examination of ANT and cSCC tissue sections using immunofluorescence and immunohistochemistry showed differential, and reverse, expression of E-cadherin and vimentin among cells within an individual tumor. Collectively, our data support a hypothesis that cSCC tumors are undergoing a hybrid EMT program, where there is variation in expression of EMT markers by cells within a tumor mass that may be facilitating invasion. This hybrid EMT program may be promoting both survival and invasiveness of the tumors. A better understanding of this hybrid EMT process may influence therapeutic strategies in more invasive disease. Citation Format: Christopher S. Pulford, Chandana K. Uppalapati, McKale R. Montgomery, Elizabeth E. Hull, Kathryn J. Leyva. A hybrid epithelial to mesenchymal transition in ex-vivo cutaneous squamous cell carcinoma tissues [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB022.

The PRMT5-LSD1 axis confers Slug dual transcriptional activities and promotes breast cancer progression

BackgroundDownregulation of epithelial markers and upregulation of mesenchymal markers are the characteristics of the epithelial to mesenchymal transition (EMT) program, which provides the metastatic advantage of breast cancer. However, the mechanism underlying the switch of EMT markers remains poorly understood.MethodsIn this study, we used the affinity purification and mass spectrometry coupled approach to identify the interactome of Slug. CoIP, GST-pulldown, ChIP, Re-ChIP, qPCR and Immunoblot were used to investigate the underlying mechanism of Slug-PRMT5-LSD1 complex. The role of PRMT5 and LSD1 in breast cancer progression was evaluated both in vivo and in vitro.ResultsHere we found that the transcription factor Slug associates with PRMT5 and LSD1 in a complex and facilitates the breast cancer invasion in vitro. Mechanistically, PRMT5 and LSD1 work with Slug to exert dual transcriptional activities to inhibit E-cadherin expression by PRMT5-catalyzed H4R3me2s and LSD1-mediated demethylation of H3K4me2 on the E-cadherin (CDH1) promoter, and activate vimentin (VIM) expression via PRMT5-driven H3R2me2s and LSD1-mediated removal of H3K9me2. Importantly, PRMT5 and LSD1 are coordinately expressed in breast cancer patients and pharmacologic perturbation of both PRMT5 and LSD1 shows a synergetic effect on the inhibition of breast tumor growth and metastasis in vivo.ConclusionsOur study suggests that PRMT5 and LSD1 function as a dual epigenetic modifier to promote Slug induced EMT program, suggesting that the inhibition of PRMT5 and LSD1 presents a potential therapeutic strategy against cancer metastasis.

Identifying drivers of breast cancer metastasis in progressively invasive subpopulations of zebrafish-xenografted MDA-MB-231

Cancer metastasis is the primary cause of the high mortality rate among human cancers. Efforts to identify therapeutic agents targeting cancer metastasis frequently fail to demonstrate efficacy in clinical trials despite strong preclinical evidence. Until recently, most preclinical studies used mouse models to evaluate anti-metastatic agents. Mouse models are time-consuming and expensive. In addition, an important drawback is that mouse models inadequately model the early stages of metastasis which plausibly leads to the poor correlation with clinical outcomes.Here, we report an in vivo model based on xenografted zebrafish embryos where we select for progressively invasive subpopulations of MDA-MB-231 breast cancer cells. A subpopulation analogous to circulating tumor cells found in human cancers was selected by injection of MDA-MB-231 cells into the yolk sacs of 2 days post-fertilized zebrafish embryos and selecting cells that migrated to the tail. The selected subpopulation derived from MDA-MB-231 cells were increasingly invasive in zebrafish. Isolation of these subpopulations and propagation in vitro revealed morphological changes consistent with activation of an epithelial-mesenchymal transition program. Differential gene analysis and knockdown of genes identified gene-candidates (DDIT4, MT1X, CTSD, and SERPINE1) as potential targets for anti-metastasis therapeutics. Furthermore, RNA-splicing analysis reinforced the importance of BIRC5 splice variants in breast cancer metastasis. This is the first report using zebrafish to isolate and expand progressively invasive populations of human cancer cells. The model has potential applications in understanding the metastatic process, identification and/or development of therapeutics that specifically target metastatic cells and formulating personalized treatment strategies for individual cancer patients.

SPARC Induces E-Cadherin Repression and Enhances Cell Migration through Integrin αvβ3 and the Transcription Factor ZEB1 in Prostate Cancer Cells

Secreted protein acidic and rich in cysteine (SPARC), or osteonectin, is a matricellular protein that modulates interactions between cells and their microenvironment. SPARC is expressed during extracellular matrix remodeling and is abundant in bone marrow and high-grade prostate cancer (PCa). In PCa, SPARC induces changes associated with epithelial–mesenchymal transition (EMT), enhancing migration and invasion and increasing the expression of EMT transcriptional factor Zinc finger E-box-binding homeobox 1 (ZEB1), but not Zinc finger protein SNAI1 (Snail) or Zinc finger protein SNAI2 (Slug). It is unknown whether the SPARC-induced downregulation of E-cadherin in PCa cells depends on ZEB1. Several integrins are mediators of SPARC effects in cancer cells. Because integrin signaling can induce EMT programs, we hypothesize that SPARC induces E-cadherin repression through the activation of integrins and ZEB1. Through stable knockdown and the overexpression of SPARC in PCa cells, we demonstrate that SPARC downregulates E-cadherin and increases vimentin, ZEB1, and integrin β3 expression. Knocking down SPARC in PCa cells decreases the tyrosine-925 phosphorylation of FAK and impairs focal adhesion formation. Blocking integrin αvβ3 and silencing ZEB1 revert both the SPARC-induced downregulation of E-cadherin and cell migration enhancement. We conclude that SPARC induces E-cadherin repression and enhances PCa cell migration through the integrin αvβ3/ZEB1 signaling pathway.

Mechanical Stretch Triggers Epithelial-Mesenchymal Transition in Keratinocytes Through Piezo1 Channel

The epithelial-mesenchymal transition (EMT) process has emerged as a central regulator of embryonic development, tissue repair and tumor malignancy. In recent years, researchers have specifically focused on how mechanical signals drive the EMT program in epithelial cells. However, how epithelial cells specifically leverage mechanical force to control the EMT process remains unclear. Here, we show that the bona fide mechanically activated cation channel Piezo1 plays a critical role in the EMT. The Piezo1 is expressed in human primary epidermal keratinocytes (HEKs) and is responsible for the mechanical stretch-induced Ca2+ concentration. Inhibition of Piezo1 activation by the inhibitor GsMTx4 or by siRNA-mediated Piezo1 knockdown influenced the morphology and migration of HEKs. Moreover, Piezo1 activity also altered EMT-correlated markers expression in response to mechanical stretch. We propose that the mechanically activated cation channel Piezo1 is an important determinant of mechanical force-induced EMT in keratinocytes and might play similar roles in other epithelial cells.

Targeting Hypoxia‐Adenosinergic Signaling to Enable Effective Anti‐Tumor Responses by Reprogramming the Immunosuppressive Tumor Microenvironment

The hypoxia‐HIF‐1ɑ‐mediated generation of extracellular adenosine (eADO) and associated A2A adenosine receptor (A2AR) signaling represent a critical mechanism for resistance to anti‐tumor immune attack in an immunosuppressive tumor microenvironment (TME). This is supported by earlier clinical and preclinical findings that tumors exhibiting refractory responses to chemotherapeutic and immunotherapeutic interventions are often characterized by low tissue oxygen tension and elevation of intracellular cAMP triggered by the binding of adenosine to the A2AR. The ensuing signaling cascade results in the downregulation of T cell activation and increased production of anti‐inflammatory factors. Several classes of drugs have been proven in preclinical studies and clinical trials to weaken this powerful biochemical mechanism of immunosuppression and enable tumor rejection. Therapeutic approaches targeting the upstream and downstream stages of hypoxia‐adenosinergic negative immune regulation (i.e. A2AR antagonists, oxygenation, inhibition of adenosine generation or adenosine degradation) represent promising co‐adjuvants capable of inducing a more immunopermissive TME. The removal of this biochemical barrier may be the key to unleashing the full therapeutic potential of immunotherapies. For instance, the epithelial‐mesenchymal transition (EMT) program, which confers the ability of cancer cells to engage in metastatic dissemination, is associated with the acquisition of resistance to immune checkpoint blockade (ICB). Recent studies have demonstrated that abrogation of the adenosine‐generating ectoenzyme CD73 sensitizes mice bearing quasi‐mesenchymal (qM) tumors to anti‐CTLA4 ICB through an increase in CD8+ T cell infiltration and cytotoxicity. Furthermore, the present study demonstrates the differential expression of adenosinergic enzymes and EMT transcription factors (EMT‐TFs) in murine breast epithelial (E) and qM carcinoma cell lines cultured in normoxic (21% oxygen) and hypoxic (1% oxygen) conditions in vitro. As hypothesized, the stabilization of HIF‐1ɑ in hypoxic conditions resulted in the upregulation of some adenosine‐generating enzymes and changes in adenosine metabolism. These results elucidate an additional mechanism through which hypoxia can contribute to the assembly of an immunosuppressive TME, while highlighting the categorical differences between the E vs qM states of carcinoma cells.

The Continuing Search for Causality between Epithelial-to-Mesenchymal Transition and the Metastatic Fitness of Carcinoma Cells.

The epithelial-to-mesenchymal transition (EMT) is an epithelial plasticity program that is associated with embryonic development and organogenesis, and which resurfaces to a certain extent following epithelial injury caused by inflammation, fibrosis, and carcinoma progression. Carcinoma cell EMT plasticity programs superimposed on inherent genetic defects have been implicated as important for metastatic dissemination and secondary tumor formation. A careful review of data-driven facts suggests that a causal relationship between any degree of EMT program and metastasis continues to be elusive, and the steps of metastasis likely involve other mechanisms influenced by the carcinoma cell genotype and the tumor microenvironment.

Genome-wide CRISPR screen identifies PRC2 and KMT2D-COMPASS as regulators of distinct EMT trajectories that contribute differentially to metastasis.

Epithelial-mesenchymal transition (EMT) programs operate within carcinoma cells in which they generate phenotypes associated with malignant progression. In their various manifestations, EMT programs enable epithelial cells to enter into a series of intermediate states arrayed along the E-M phenotypic spectrum. At present, we lack a coherent understanding of how carcinoma cells control their entrance into and continued residence in these various states, and which of these states favor the process of metastasis. Here, we characterize a layer of EMT-regulating machinery that governs E-M plasticity (EMP). This machinery consists of two chromatin-modifying complexes, PRC2 and KMT2D-COMPASS, that operate as critical regulators to maintain a stable epithelial state. Interestingly, loss of these two complexes unlocks two distinct EMT trajectories. Dysfunction of PRC2, but not KMT2D-COMPASS, yields a quasi-mesenchymal state that is associated with highly metastatic capabilities and poor survival of breast cancer patients, suggesting great caution should be applied when PRC2 inhibitors are evaluated clinically in certain patient cohorts. These observations identify epigenetic factors that regulate E-M plasticity, determine specific intermediate EMT states and, as a direct consequence, govern the metastatic ability of carcinoma cells.

Relaxin inhibits renal fibrosis and the epithelial-to-mesenchymal transition via the Wnt/β-catenin signaling pathway

Renal fibrosis is a common characteristic and the final pathological mechanism of chronic kidney disease (CKD). Although CKD remains incurable, inhibition of renal fibrosis is beneficial to inhibit the CKD process. Relaxin alleviates renal fibrosis in some experimental models, but its mechanism remains unclear. In the following, we studied the regulatory effect of relaxin on epithelial-mesenchymal transition (EMT) after unilateral ureteral obstruction (UUO). Our results demonstrate that relaxin could downregulate Wnt/β-catenin signaling and decrease EMT, thus protecting against loss of transporters in tubular epithelial cells (TECs) and abrogate renal interstitial fibrosis following UUO. We confirmed that relaxin can downregulate Wnt/β-catenin signaling and decrease EMT in NRK52E, thus abrogating G2 cell cycle arrest in vitro experiments. Therefore, a novel mechanism by which relaxin is antifibrotic is that relaxin regulates the EMT program of TECs via Wnt/β-catenin signaling pathway. The inhibition of EMT contributes to protecting the functional capabilities of TECs and promoting the regeneration of TECs.

Multiple roles of m6A methylation in epithelial-mesenchymal transition.

Epithelial-mesenchymal transition (EMT) plays an important role in migration and invasion of cancer cell and the development of tissue fibrosis diseases. N6-methyladenosine (m6A) is the most extensive type of RNA methylation and has aroused extensive interest in recent years. However, m6A methylation seems to play different roles in different cancer cells and tissue fibrotic diseases. To determine the function of m6A methylation in EMT, we summarized the molecular mechanism of EMT and recent progress in the regulation of EMT by m6A methylation, suggesting that m6A methylation targets EMT program by affecting the expression of transcription factors, EMT markers, long noncoding RNA and EMT-associated signaling pathways, which provides more possibilities for early diagnosis and treatment.