Epithelial-mesenchymal Transition Plasticity Research Articles

Orchestrated desaturation reprogramming from stearoyl-CoA desaturase to fatty acid desaturase 2 in cancer epithelial-mesenchymal transition and metastasis.

Adaptative desaturation in fatty acid (FA) is an emerging hallmark of cancer metabolic plasticity. Desaturases such as stearoyl-CoA desaturase (SCD) and fatty acid desaturase 2 (FADS2) have been implicated in multiple cancers, and their dominant and compensatory effects have recently been highlighted. However, how tumors initiate and sustain their self-sufficient FA desaturation to maintain phenotypic transition remains elusive. This study aimed to explore the molecular orchestration of SCD and FADS2 and their specific reprogramming mechanisms in response to cancer progression. The potential interactions between SCD and FADS2 were explored by bioinformatics analyses across multiple cancer cohorts, which guided subsequent functional and mechanistic investigations. The expression levels of desaturases were investigated with online datasets and validated in both cancer tissues and cell lines. Specific desaturation activities were characterized through various isomer-resolved lipidomics methods and sensitivity assays using desaturase inhibitors. In-situ lipid profiling was conducted using multiplex stimulated Raman scattering imaging. Functional assays were performed both in vitro and in vivo, with RNA-sequencing employed for the mechanism verification. After integration of the RNA-protein-metabolite levels, the data revealed that a reprogramming from SCD-dependent to FADS2-dependent desaturation was linked to cancer epithelial-mesenchymal transition (EMT) and progression in both patients and cell lines. FADS2 overexpression and SCD suppression concurrently maintained EMT plasticity. A FADS2/β-catenin self-reinforcing feedback loop facilitated the degree of lipid unsaturation, membrane fluidity, metastatic potential and EMT signaling. Moreover, SCD inhibition triggered a lethal apoptosis but boosted survival plasticity by inducing EMT and enhancing FA uptake via adenosine monophosphate-activated protein kinase activation. Notably, this desaturation reprogramming increased transforming growth factor-β2, effectively sustaining aggressive phenotypes and metabolic plasticity during EMT. These findings revealed a metabolic reprogramming from SCD-dependent to FADS2-dependent desaturation during cancer EMT and progression, which concurrently supports EMT plasticity. Targeting desaturation reprogramming represents a potential vulnerability for cancer metabolic therapy.

Abstract C073: FOLFIRINOX with Glycogen Synthase Kinase-3 Beta (GSK-3β) Inhibitor Elraglusib and Transforming Growth Factor- β (TGFβ) Inhibitor Losartan in Untreated Metastatic Pancreatic Ductal Adenocarcinoma(PDAC): Interim analysis of safety cohort

Abstract Introduction: Epithelial-mesenchymal transition (EMT) is one of the key drivers of aggressive biology and development of chemoresistance in PDAC. Inhibition of glycogen synthase kinase 3β (GSK3β) may offer a promising novel approach for modulating dynamic EMT plasticity to overcome resistance to FOLFIRINOX (5-Fluororuacil, Irinotecan, Oxaliplatin, FFX). Methods: Cell line panels comprising both epithelial (E) and quasi-mesenchymal (QM) subtypes were used and treated with IC50 (0.3125 mM) and IC100 (1.25 mM) doses of elraglusib (ELR). Gene expression patters in response to treatment were analyzed using bulk RNA sequencing. 6 patients in the safety run-in cohort of NCT05077800 treated with standard doses of FFX, ELR and losartan were included in this interim analysis. Biopsy specimens were processed for RNA-in situ hybridization (RNA-ISH), a clinically validated assay, and Nanostring (GeoMx) spatial transcriptomics. Results: In preclinical models, exposure to the higher IC100 (1.25 mM) doses of ELR in the QM cell lines caused a shift in transcriptional expression patterns similar to the E cell line, with strong downregulation of EMT. FFX exposure alone in QM cell lines was associated with significant resistance, but addition of ELR (even at IC50 dose) caused a synergistic effect with decreased cell viability. However, in the E cell lines, there was no benefit from addition of ELR. In the safety cohort, clinical results are encouraging with a long-term (>6 month) response in 3/6 patients. 2/6 achieved partial response, 1/6 had stable disease. Nanostring (GeoMx) spatial transcriptomic profiling on available biopsy samples showed significant global gene expression changes before and after treatment. There were concordant changes in 97 differentially expressed genes (DEGs) within the epithelial compartment with treatment, similar to ELR induced changes in PDAC cell lines, with a shift in transcriptional expression patterns from QM to E subtype. Gene set enrichment analysis demonstrated downregulation of the EMT pathway, as well as decreased TGF-β signaling. RNA-ISH analysis on baseline biopsy samples showed that the two partial (best) responders had higher degrees of QM marker expression (82.58% and 63.76%). The regimen was well tolerated with no dose limiting toxicity noted in the safety cohort. Conclusion: Our experiments demonstrate that the E subtype PDAC cell lines are inherently sensitive to FFX chemotherapy with no added advantage with GSK3β inhibition. Meanwhile, GSK3β inhibition in QM cell lines induces mesenchymal to epithelial transition, thereby rendering it sensitive to FFX. The data from our safety cohort provide a clinical proof of concept that GSK-3β inhibition with ELR, in combination with FFX, may be an effective therapeutic strategy in metastatic PDAC. NCT05077800 is currently enrolling. Citation Format: Priyadarshini Pathak, Eric Lin, Ildiko Phillips, David Ting, Colin Weekes. FOLFIRINOX with Glycogen Synthase Kinase-3 Beta (GSK-3β) Inhibitor Elraglusib and Transforming Growth Factor- β (TGFβ) Inhibitor Losartan in Untreated Metastatic Pancreatic Ductal Adenocarcinoma(PDAC): Interim analysis of safety cohort [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr C073.

MicroRNA signatures differentiate types, grades, and stages of breast invasive ductal carcinoma (IDC): miRNA-target interacting signaling pathways

BackgroundInvasive ductal carcinoma (IDC) is the most common form of breast cancer which accounts for 85% of all breast cancer diagnoses. Non-invasive and early stages have a better prognosis than late-stage invasive cancer that has spread to lymph nodes. The involvement of microRNAs (miRNAs) in the initiation and progression of breast cancer holds great promise for the development of molecular tools for early diagnosis and prognosis. Therefore, developing a cost effective, quick and robust early detection protocol using miRNAs for breast cancer diagnosis is an imminent need that could strengthen the health care system to tackle this disease around the world.MethodsWe have analyzed putative miRNAs signatures in 100 breast cancer samples using two independent high fidelity array systems. Unique and common miRNA signatures from both array systems were validated using stringent double-blind individual TaqMan assays and their expression pattern was confirmed with tissue microarrays and northern analysis. In silico analysis were carried out to find miRNA targets and were validated with q-PCR and immunoblotting. In addition, functional validation using antibody arrays was also carried out to confirm the oncotargets and their networking in different pathways. Similar profiling was carried out in Brca2/p53 double knock out mice models using rodent miRNA microarrays that revealed common signatures with human arrays which could be used for future in vivo functional validation.ResultsExpression profile revealed 85% downregulated and 15% upregulated microRNAs in the patient samples of IDC. Among them, 439 miRNAs were associated with breast cancer, out of which 107 miRNAs qualified to be potential biomarkers for the stratification of different types, grades and stages of IDC after stringent validation. Functional validation of their putative targets revealed extensive miRNA network in different oncogenic pathways thus contributing to epithelial-mesenchymal transition (EMT) and cellular plasticity.ConclusionThis study revealed potential biomarkers for the robust classification as well as rapid, cost effective and early detection of IDC of breast cancer. It not only confirmed the role of these miRNAs in cancer development but also revealed the oncogenic pathways involved in different progressive grades and stages thus suggesting a role in EMT and cellular plasticity during breast tumorigenesis per se and IDC in particular. Thus, our findings have provided newer insights into the miRNA signatures for the classification and early detection of IDC.

Single-Cell Enzymatic Screening for Epithelial Mesenchymal Transition with an Ultrasensitive Superwetting Droplet-Array Microchip.

The phenotypic changes of circulating tumor cells (CTCs) during the epithelial-mesenchymal transition (EMT) have been a hot topic in tumor biology and cancer therapeutic development. Here, an integrated platform of single-cell fluorescent enzymatic assays with superwetting droplet-array microchips (SDAM) for ultrasensitive functional screening of epithelial-mesenchymal sub-phenotypes of CTCs is reported. The SDAM can generate high-density, volume well-defined droplet (0.66 nL per droplet) arrays isolating single tumor cells via a discontinuous dewetting effect. It enables sensitive detection of MMP9 enzyme activities secreted by single tumor cells, correlating to their epithelial-mesenchymal sub-phenotypes. In the pilot clinical double-blind tests, the authors have demonstrated that SDAM assays allow for rapid identification and functional screening of CTCs with different epithelial-mesenchymal properties. The consistency with the clinical outcomes validates the usefulness of single-cell secreted MMP9 as a biomarker for selective CTC screening and tumor metastasis monitoring. Convenient addressing and recovery of individual CTCs from SDAM have been demonstrated for gene mutation sequencing, immunostaining, and transcriptome analysis, revealing new understandings of the signaling pathways between MMP9 secretion and the EMT regulation of CTCs. The SDAM approach combined with sequencing technologies promises to explore the dynamic EMT plasticity of tumors at the single-cell level.

LncRNA LITATS1 suppresses TGF‐β‐induced EMT and cancer cell plasticity by potentiating TβRI degradation

Epithelial cells acquire mesenchymal phenotypes through epithelial‐mesenchymal transition (EMT) during cancer progression. However, how epithelial cells retain their epithelial traits and prevent malignant transformation is not well understood. Here, we report that the long noncoding RNA LITATS1 (LINC01137, ZC3H12A‐DT) is an epithelial gatekeeper in normal epithelial cells and inhibits EMT in breast and non‐small cell lung cancer cells. Transcriptome analysis identified LITATS1 as a TGF‐β target gene. LITATS1 expression is reduced in lung adenocarcinoma tissues compared with adjacent normal tissues and correlates with a favorable prognosis in breast and non‐small cell lung cancer patients. LITATS1 depletion promotes TGF‐β‐induced EMT, migration, and extravasation in cancer cells. Unbiased pathway analysis demonstrated that LITATS1 knockdown potently and selectively potentiates TGF‐β/SMAD signaling. Mechanistically, LITATS1 enhances the polyubiquitination and proteasomal degradation of TGF‐β type I receptor (TβRI). LITATS1 interacts with TβRI and the E3 ligase SMURF2, promoting the cytoplasmic retention of SMURF2. Our findings highlight a protective function of LITATS1 in epithelial integrity maintenance through the attenuation of TGF‐β/SMAD signaling and EMT.

Effect of eribulin on epithelial-mesenchymal transition plasticity in metastatic breast cancer: An exploratory, prospective study.

Epithelial-mesenchymal transition (EMT) plays a pivotal role in cancer metastasis and treatment resistance, which worsens prognosis. In phase III trials, eribulin improved overall survival in metastatic breast cancer (MBC) patients. In preclinical studies, eribulin suppressed EMT. However, clinical data on the use of eribulin for MBC patients are limited. In this exploratory, prospective study, we examined the effect of eribulin on EMT in MBC patients. Twenty-two patients aged 44-82 years with recurrent breast cancer or MBC were treated with eribulin. Breast cancer tissue samples were obtained before treatment and on Day 15 ± 5 of the first cycle of eribulin treatment. EMT markers (E-cadherin, claudin-3, vimentin, and N-cadherin) were analyzed using western blotting. EMT changes were evaluated based on the ratio of epithelial to mesenchymal markers before and after treatment in individual tumors. E-cadherin/vimentin, claudin-3/vimentin, E-cadherin/N-cadherin, and claudin-3/N-cadherin ratios were significantly higher after treatment (p=.007, p=.005, p=.006, and p=.011, respectively). Based on E-cadherin/vimentin, 65.0% of tumors shifted to an epithelial phenotype, as compared to 66.7% based on claudin-3/vimentin, 84.6% based on E-cadherin/N-cadherin, and 71.4% based on claudin-3/N-cadherin ratios. Thus, our results showed that eribulin suppressed EMT in breast cancer tissues.

Multiomics characterization implicates PTK7 in ovarian cancer EMT and cell plasticity and offers strategies for therapeutic intervention

Most patients with ovarian cancer (OC) are diagnosed at a late stage when there are very few therapeutic options and a poor prognosis. This is due to the lack of clearly defined underlying mechanisms or an oncogenic addiction that can be targeted pharmacologically, unlike other types of cancer. Here, we identified protein tyrosine kinase 7 (PTK7) as a potential new therapeutic target in OC following a multiomics approach using genetic and pharmacological interventions. We performed proteomics analyses upon PTK7 knockdown in OC cells and identified novel downstream effectors such as synuclein-γ (SNCG), SALL2, and PP1γ, and these findings were corroborated in ex vivo primary samples using PTK7 monoclonal antibody cofetuzumab. Our phosphoproteomics analyses demonstrated that PTK7 modulates cell adhesion and Rho-GTPase signaling to sustain epithelial-mesenchymal transition (EMT) and cell plasticity, which was confirmed by high-content image analysis of 3D models. Furthermore, using high-throughput drug sensitivity testing (525 drugs) we show that targeting PTK7 exhibited synergistic activity with chemotherapeutic agent paclitaxel, CHK1/2 inhibitor prexasertib, and PLK1 inhibitor GSK461364, among others, in OC cells and ex vivo primary samples. Taken together, our study provides unique insight into the function of PTK7, which helps to define its role in mediating aberrant Wnt signaling in ovarian cancer.

Macrophage induced ERK-TGF-β1 signaling in MCF7 breast cancer cells result in reversible cancer stem cell plasticity and epithelial mesenchymal transition

BackgroundBreast cancer is a heterogenous disease composed of multiple clonal populations and the mechanism by which the tumor microenvironment induces cancer stem cell plasticity is not fully understood. MethodsMCF7 breast cancer cells were treated with macrophage conditioned medium (MɸCM). PD98059 and SB431542 were used for ERK and TGF-βR inhibition respectively. Epithelial-mesenchymal transition (EMT) and cancer stem cell markers (CSC) were studied using qRT-PCR and flowcytometry. SCID mice were used for animal experiments. ResultsMɸCM- induced ERK/TGF-β1 signaling led to enrichment of CSC and EMT in MCF7 cells and mammospheres. These effects were abrogated by both MEK inhibitor PD98059 (TGF-β1 synthesis) and SB431542 (TGF-β1 signaling). The increase in CSC was both hybrid (ALDH1+) and mesenchymal (CD44+ CD24− cells). Increase in hybrid E/M state was at a single cell level as confirmed by the increase in both claudin-1 (E) and vimentin (M). This did not have any growth advantage in SCID mice and monitoring of CSC and EMT markers before and after growth in SCID mice indicated reversal of these markers in tumor cells recovered from mice. Removal of MɸCM and neutralization of TNF-α, IL-6 and IL-1β in MɸCM abrogated ERK phosphorylation, TGF-β and CSC enrichment indicating the requirement of continuous signaling for maintenance. ConclusionsERK signaling plays an important role in MɸCM- induced EMT and CSC plasticity which is completely reversible upon withdrawal of signals. General significanceOur experimental observations support the semi-independent nature of EMT-stemness connection which is very dynamic and reversible depending on the microenvironment.

Yiqi Jianpi Huayu Jiedu Decoction Inhibits Metastasis of Colon Adenocarcinoma by Reversing Hsa-miR-374a-3p/Wnt3/β-Catenin-Mediated Epithelial-Mesenchymal Transition and Cellular Plasticity.

Colon adenocarcinoma (COAD) accounts for 95% of colon cancer cases, with the 5-year survival rate significantly affected by local or distant metastases. Yiqi Jianpi Huayu Jiedu decoction (YJHJD), based on the theory of “nourish qi, invigorate the spleen, remove blood stasis, and detoxify”, has long been applied and shown to be remarkable in the prevention and treatment of gastrointestinal tumors. However, the underlying therapeutic mechanisms of YJHJD have not been fully elucidated. Herein, we first confirmed hsa-miR-374a-3p as a tumor suppressor based on its lower expression in the plasma of patients with COAD with liver metastasis and association with more advanced local progression. We also verified WNT3 as a potential target of hsa-miR-374a-3p and observed its increased expression in COAD tissues. Furthermore, we showed that the hsa-miR-374a-3p/Wnt3/β-catenin axis was responsible for epithelial–mesenchymal transition (EMT) and cellular plasticity in COAD, as well as poorer patient prognosis. Our results showed that YJHJD inhibited motility and colony potential in vitro, as well as liver metastasis of COAD in vivo. Moreover, YJHJD induced a reversal of EMT and cellular plasticity-related molecular expression, increased hsa-miR-374a-3p, and decreased Wnt3 and β-catenin levels. In addition, silencing of hsa-miR-374a-3p weakened YJHJD inhibition, whereas the β-catenin inhibitor XAV939 partially repaired it. Taken together, these results demonstrated that YJHJD suppressed the EMT and cellular plasticity of COAD by regulating hsa-miR-374a-3p/Wnt3/β-catenin signaling.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Activation of epithelial-mesenchymal transition process during breast cancer progression - the impact of molecular subtype and stromal composition.

Breast cancer (BC) is a heterogeneous disease with different molecular subtypes, which can be defined by oestrogen (ER), progesterone (PR) and human epidermal growth factor (HER2) receptors' status as luminal, HER2+ and triple negative (TNBC). Molecular subtypes also differ in their epithelial-mesenchymal phenotype, which might be related to their aggressiveness, as activation of the epithelial-mesenchymal transition (EMT) is linked with increased ability of cancer cells to survive andmetastasize. Nevertheless, the reverse process of mesenchymal-epithelial transition was shown tobe required to sustain metastatic colonization. In this study we aimed to analyse activation of the EMT process in primary tumours (PT), which have (N+) or have not (N-) colonized the lymph nodes, as well as the lymph nodes metastases (LNM) themselves in 88 BC patients. We showed that luminal N- PT have the lowest activation of the EMT process (27%), in comparison to N+ PT (48%,p=0.06). On the other hand, TNBC do not show statistically significant EMT activation at the stage before lymph colonization (N-, 83%) and after colonization of the lymph nodes (N+, 63%, p=0.58). TNBC are also the least plastic (unable to change the EMT phenotype) in terms of turning EMT on or off between matched PT and LNM (0% EMT plasticity in TNBC vs 36% plasticity in luminal tumours). Moreover, in TNBC activation of EMT was correlated with increased cell division rate of the PT- inmesenchymal TNBC PT median Ki-67 was 45% in comparison to 10% in epithelial TNBC PT (p=0.002), whereas in PT of luminal subtypes Ki-67 did not differ between epithelial andmesenchymal phenotypes. Profiling of immunotranscriptome of epithelial and mesenchymal luminal BC with Nanostring technology revealed that N- PT with epithelial phenotype were enriched ininflammatory response signatures, whereas N+ mesenchymal cancers showed elevated MHC class II antigen presentation. Overall, activation of EMT changes during cancer progression and metastatic colonization of the lymph nodes depending on the PT molecular subtype and is related to differences in stromal signatures. Activation of EMT is associated with colonizing phenotype in luminal PT andproliferative phenotype of TNBC.

Zinc-Dependent Regulation of ZEB1 and YAP1 Coactivation Promotes Epithelial-Mesenchymal Transition Plasticity and Metastasis in Pancreatic Cancer

Pancreatic cancer is characterized by extensive metastasis. Epithelial-mesenchymal transition (EMT) plasticity plays a critical role in tumor progression and metastasis by maintaining the transition between EMT and mesenchymal-epithelial transition states. Our aim is to understand the molecular events regulating metastasis and EMT plasticity in pancreatic cancer. The interactions between a cancer-promoting zinc transporter ZIP4, a zinc-dependent EMT transcriptional factor ZEB1, a coactivator YAP1, and integrin α3 (ITGA3) were examined in human pancreatic cancer cells, clinical specimens, spontaneous mouse models (KPC and KPCZ) and orthotopic xenografts, and 3-dimensional spheroid and organoid models. Correlations between ZIP4, miR-373, and its downstream targets were assessed by RNA in situ hybridization and immunohistochemical staining. The transcriptional regulation of ZEB1, YAP1, and ITGA3 by ZIP4 wasdetermined by chromatin immunoprecipitation, co-immunoprecipitation, and luciferase reporter assays. The Hippo pathway effector YAP1 is a potent transcriptional coactivator and forms a complex with ZEB1 to activate ITGA3 transcription through the YAP1/transcriptional enhanced associate domain (TEAD) binding sites in human pancreatic cancer cells and KPC-derived mouse cells. ZIP4 upregulated YAP1 expression via activation of miR-373 and inhibition of the YAP1 repressor large tumor suppressor 2 kinase (LATS2). Furthermore, upregulation of ZIP4 promoted EMT plasticity, cell adhesion, spheroid formation, and organogenesis both in human pancreatic cancer cells, 3-dimensional spheroid model, xenograft model, and spontaneous mouse models (KPC andKPCZ) through ZEB1/YAP1-ITGA3 signaling axis. We demonstrated that ZIP4 activates ZEB1 and YAP1 through distinct mechanisms. The ZIP4-miR-373-LATS2-ZEB1/YAP1-ITGA3 signaling axis has a significant impact on pancreatic cancer metastasis and EMT plasticity.

Impact of intercellular connectivity on epithelial mesenchymal transition plasticity

Epithelial mesenchymal transition (EMT) in development, tissue repair and carcinogenesis involves cellular plasticity with varying degrees of epithelial and mesenchymal properties. Several recent studies have focused on EMT phenotypic dynamism; however, information on cellular interaction in the context of EMT is inadequate. In our previous study, we investigated EMT phenotypic plasticity and anticipated it as a population driven interactive process. Present study has characterized cellular connectivity as a representative of interactivity during EMT in epithelial normal and cancer cell. It has also explored dynamism of connectivity and phenotype employing Markov model. Further, plasticity was substantiated with cell surface microvilli and molecular marker. The study unveiled interplay between phenotype and connectivity too. Findings have revealed that intercellular connectivity fueled EMT plasticity and its dynamism was more prominent in cancer population. However, normal cells are more vibrant in transition and phenotypic plasticity. We have proposed connectivity plasticity as a hallmark of EMT and needs to be studied in depth. Present study also paves the way in translating in vitro EMT findings in histopathological practices.

ERa suppresses liver cancer EMT and amoeboid movement by targeting Ga12

Several reports demonstrate the association of certain cancer progression and estrogen receptor alpha (ERa) expression. Due to poor prognosis and high relapse, hepatocellular carcinoma (HCC) is the second most common cancer worldwide. Moreover, aggressiveness and mortality of HCC is more frequent in men than women. Ga12 gep oncogene plays a critical role in promoting epithelial‐mesenchymal transition (EMT), a well‐established mechanism for tumor invasion. We previously showed that Ga12 is overly expressed in HCC patients. Here, we report an inverse correlation of ERa and Ga12 expression in HCC, which may contribute to the cancer metastasis and patient mortality. ERa transcriptionally inhibited Ga12 expression in a cancer cell model. In addition, tumor cells can take another modes of movement, characterized as amoeboid movement. Both EMT and amoeboid movement are necessary for an efficient metastasis of cancer cell. Since ROCK is one of the main downstream molecules of the Ga12 pathway and is known to activate amoeboid motility, we hypothesized whether ERa may affect amoeboid phenotype by modulating Ga12 signaling pathway, and found that ERa activation inhibited amoeboidal cell migration/invasion in conjunction with Ga12 repression. Moreover, we found microRNA‐141 and ‐200a as functional molecules affected downstream from the ERa‐Ga12 pathway, and their targeting of PTP4A1. Together, our results show that the ERa‐Ga12 pathway may play a role in targeting EMT and amoeboid movement plasticity of liver cancer, which may account for the gender disparity in HCC incidence and malignant progression.Support or Funding InformationThis work was financially supported by the Bio & Medical Technology Development Program of the NRF funded by the Korean government, MSIP (2015M3A9B6074045).

The role of GRHL2 and epigenetic remodeling in epithelial\u2013mesenchymal plasticity in ovarian cancer cells

Cancer cells exhibit phenotypic plasticity during epithelial–mesenchymal transition (EMT) and mesenchymal–epithelial transition (MET) involving intermediate states. To study genome-wide epigenetic remodeling associated with EMT plasticity, we integrate the analyses of DNA methylation, ChIP-sequencing of five histone marks (H3K4me1, H3K4me3, H3K27Ac, H3K27me3 and H3K9me3) and transcriptome profiling performed on ovarian cancer cells with different epithelial/mesenchymal states and on a knockdown model of EMT suppressor Grainyhead-like 2 (GRHL2). We have identified differentially methylated CpG sites associated with EMT, found at promoters of epithelial genes and GRHL2 binding sites. GRHL2 knockdown results in CpG methylation gain and nucleosomal remodeling (reduction in permissive marks H3K4me3 and H3K27ac; elevated repressive mark H3K27me3), resembling the changes observed across progressive EMT states. Epigenetic-modifying agents such as 5-azacitidine, GSK126 and mocetinostat further reveal cell state-dependent plasticity upon GRHL2 overexpression. Overall, we demonstrate that epithelial genes are subject to epigenetic control during intermediate phases of EMT/MET involving GRHL2.

In Vitro Effect of Estradiol and Progesterone on Ovine Amniotic Epithelial Cells.

Amniotic epithelial cells (AECs), an emerging source of extrafoetal stem cells, have recently attracted attention for their great regenerative potential. Since AEC amplifications are accompanied by the loss of their native epithelial phenotype and by the progressive reduction of relevant biological properties, the issue to be addressed is the development of effective culture protocols. In this context, recently, it has been demonstrated that progesterone (P4) supplementation during ovine AEC (oAEC) expansion could prevent the undesirable epithelial-mesenchymal transition (EMT). In contrast, there is no information to date on the role of the other pregnancy steroids in culture. With this aim, the present study has been designed to clarify the impact of estradiol (E2), alone or in combination with P4 (12.5 μM and 25 μM), during oAEC amplification. Steroid supplementations were assessed by testing oAEC proliferation, stemness, EMT, and osteogenic or chondrogenic plasticity. The results indicated that EMT can be prevented exclusively in the presence of high doses of P4, while it occurred rapidly in cells exposed to E2 as denoted by protein (cytokeratin-8 and alpha-SMA) and gene expression (vimentin and snail) profiles. Moreover, steroid exposure was able to influence highly oAEC plasticity. Particularly, P4-treated cells displayed a precommitment towards osteogenic lineage, confirmed by the upregulation of OCN, RUNX2, and the greater deposition of calcium nodules. Conversely, P4 exposure inhibited oAEC chondrogenic differentiation, which was induced in E2-treated cells as confirmed by the upregulation of chondrogenesis-related genes (SOX9, ACAN, and COL2A1) and by the accumulation of Alcian blue-positive extracellular matrix. Simultaneously, E2-treated cells remained unresponsive to osteogenic inductive stimuli. In conclusion, media supplementation with high doses of steroids may be adopted to modulate phenotype and plasticity during oAEC amplification. Relevantly, the osteo or chondro steroid-induced precommitment may open unprecedented cell-based therapies to face the unsolved orthopaedic issues related to osteochondral regeneration.

Characterisation of mesenchymal colon tumour-derived cells in tumourspheres as a model for colorectal cancer progression

Cellular plasticity, the ability of cells to switch from an epitheial phenotype to a mesenchymal one and vice versa, plays a crucial role in tumour progression and metastases development. In 20-25% of patients with colon cancer and in 18% of patients with rectal cancer, metastases are present at the time of the first diagnosis. They are the first cause of colorectal cancer (CRC)-related mortality, defining stage IV CRC, which is characterized by a relatively short overall survival. We previously isolated two primary colon adenocarcinoma cell cultures that had undergone epithelial-mesenchymal transition (EMT), one with a high microsatellite instability phenotype (T88) and one with a chromosomal instability phenotype (T93). The aim of this study was to establish a model with which to study EMT, stemness features and cell plasticity in cancer progression and to examine the effects of incubation with lithium chloride (LiCl), a specific glycogen synthase kinase 3 β (GSK-3β) inhibitor, on these cellular processes. Indeed, GSK3β is an important regulator of cell survival, which promotes tumourigenesis in colon cells by facilitating the crosstalk between colorectal cancer pathways. Thus, we further characterized our system of adherent primary mesenchymal colon cancer cells and their paired tumourspheres by examining the expression and localisation of a panel of markers, including E- and N-cadherin, CD133, CD44v6, aldehyde dehydrogenase 1 (ALDH1) and leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5). We also characterised the molecular features of these tumourspheres and examined their response to LiCl. Furthermore, we explored the effects of LiCl on cell motility and plasticity. We demonstrated that LiCl reduced cell migration, stemness features and cell plasticity. We also observed the atypical nuclear localisation of membrane proteins, including N-cadherin, CD133 and CD44v6 in mesenchymal tumour cells. Of note, CD133 and CD44v6 appeared to localise at the plasma membrane in cells with a more epithelial phenotype, suggesting that the cytoplasmic/nuclear localisation of these proteins could favour and characterize cell plasticity in colorectal cancer progression.

Breast tumor cell-specific knockout of Twist1 inhibits cancer cell plasticity, dissemination, and lung metastasis in mice

Twist1 is an epithelial-mesenchymal transition (EMT)-inducing transcription factor (TF) that promotes cell migration and invasion. To determine the intrinsic role of Twist1 in EMT and breast cancer initiation, growth, and metastasis, we developed mouse models with an oncogene-induced mammary tumor containing wild-type (WT) Twist1 or tumor cell-specific Twist1 knockout (Twist1TKO). Twist1 knockout showed no effects on tumor initiation and growth. In both models with early-stage tumor cells, Twist1, and mesenchymal markers were not expressed, and lung metastasis was absent. Twist1 expression was detected in ∼6% of the advanced WT tumor cells. Most of these Twist1+ cells coexpressed several other EMT-inducing TFs (Snail, Slug, Zeb2), lost ERα and luminal marker K8, acquired basal cell markers (K5, p63), and exhibited a partial EMT plasticity (E-cadherin+/vimentin+). In advanced Twist1TKO tumor cells, Twist1 knockout largely diminished the expression of the aforementioned EMT-inducing TFs and basal and mesenchymal markers, but maintained the expression of the luminal markers. Circulating tumor cells (CTCs) were commonly detected in mice with advanced WT tumors, but not in mice with advanced Twist1TKO tumors. Nearly all WT CTCs coexpressed Twist1 with other EMT-inducing TFs and both epithelial and mesenchymal markers. Mice with advanced WT tumors developed extensive lung metastasis consisting of luminal tumor cells with silenced Twist1 and mesenchymal marker expression. Mice with advanced Twist1TKO tumors developed very little lung metastasis. Therefore, Twist1 is required for the expression of other EMT-inducing TFs in a small subset of tumor cells. Together, they induce partial EMT, basal-like tumor progression, intravasation, and metastasis.

EMT: Present and future in clinical oncology.

Epithelial/mesenchymal transition (EMT) has emerged as a key regulator of metastasis by facilitating tumor cell invasion and dissemination to distant organs. Recent evidences support that the reverse mesenchymal/epithelial transition (MET) is required for metastatic outgrowth; moreover, the existence of hybrid epithelial/mesenchymal (E/M) phenotypes is increasingly being reported in different tumor contexts. The accumulated data strongly support that plasticity between epithelial and mesenchymal states underlies the dissemination and metastatic potential of carcinoma cells. However, the translation into the clinics of EMT and epithelial plasticity processes presents enormous challenges and still remains a controversial issue. In this review, we will evaluate current evidences for translational applicability of EMT and depict an overview of the most recent EMT in vivo models, EMT marker analyses in human samples as well as potential EMT therapeutic approaches and ongoing clinical trials. We foresee that standardized analyses of EMT markers in solid and liquid tumor biopsies in addition to innovative tools targeting the E/M states will become promising strategies for future translation to the clinical setting.

Prrx1 isoform switching regulates pancreatic cancer invasion and metastatic colonization.

The two major isoforms of the paired-related homeodomain transcription factor 1 (Prrx1), Prrx1a and Prrx1b, are involved in pancreatic development, pancreatitis, and carcinogenesis, although the biological role that these isoforms serve in the systemic dissemination of pancreatic ductal adenocarcinoma (PDAC) has not been investigated. An epithelial-mesenchymal transition (EMT) is believed to be important for primary tumor progression and dissemination, whereas a mesenchymal-epithelial transition (MET) appears crucial for metastatic colonization. Here, we describe novel roles for both isoforms in the metastatic cascade using complementary in vitro and in vivo models. Prrx1b promotes invasion, tumor dedifferentiation, and EMT. In contrast, Prrx1a stimulates metastatic outgrowth in the liver, tumor differentiation, and MET. We further demonstrate that the switch from Prrx1b to Prrx1a governs EMT plasticity in both mouse models of PDAC and human PDAC. Last, we identify hepatocyte growth factor ( HGF) as a novel transcriptional target of Prrx1b. Targeted therapy of HGF in combination with gemcitabine in a preclinical model of PDAC reduces primary tumor volume and eliminates metastatic disease. Overall, we provide new insights into the isoform-specific roles of Prrx1a and Prrx1b in primary PDAC formation, dissemination, and metastatic colonization, allowing for novel therapeutic strategies targeting EMT plasticity.