Cadherin switching: essential for behavioral but not morphological changes during an epithelium-to-mesenchyme transition

Harnessing transcriptional regulation of alternative end-joining to predict cancer treatment

Alternative end-joining (alt-EJ) is an error-prone DNA repair pathway that cancer cells deficient in homologous recombination rely on, making them vulnerable to synthetic lethality via inhibition of poly(ADP-ribose) polymerase (PARP). Targeting alt-EJ effector DNA polymerase theta (POLθ), which synergizes with PARP inhibitors and can overcome resistance, is of significant preclinical and clinical interest. However, the transcriptional regulation of alt-EJ and its interactions with processes driving cancer progression remain poorly understood. Here, we show that alt-EJ is suppressed by hypoxia while positively associated with MYC (myelocytomatosis oncogene) transcriptional activity. Hypoxia reduces PARP1 and POLQ expression, decreases MYC binding at their promoters, and lowers PARylation and alt-EJ-mediated DNA repair in cancer cells. Tumors with HIF1A mutations overexpress the alt-EJ gene signature. Inhibition of hypoxia-inducible factor 1α or HIF1A expression depletion, combined with PARP or POLθ inhibition, synergistically reduces the colony-forming capacity of cancer cells. Deep learning reveals the anticorrelation between alt-EJ and hypoxia across regions in tumor images, and the predictions for these and MYC activity achieve area under the curve values between 0.70 and 0.86. These findings further highlight the critical role of hypoxia in modulating DNA repair and present a strategy for predicting and improving outcomes centered on targeting alt-EJ.

Electromagnetic field as a possible inhibitor of tumor invasion by declining E-cadherin/N-cadherin switching in triple negative breast cancer

Breast cancer has been recognized as the most common cancer affecting women. Extremely low-frequency electromagnetic field (ELF-EMF) exposure can influence cellular activities such as cell-cell junctions and metastasis. However, more research is required to determine these fields' underlying mechanisms of action. Since cadherin switching is an important process during EMT (epithelial-mesenchymal transition), in this study, cadherin switching was regarded as one of the probable mechanisms of the effect of ELF-EMFs on metastasis suppression. For five days, breast cells received a 1 Hz, 100mT ELF-EMF (2 h/day). Cell invasion and migration were assessed in vitro by the Scratch wound healing assay and Transwell culture chambers. The expression of E- and N-cadherin was assessed using real-time PCR, western blotting, and Immunocytochemistry. ELF-EMF dramatically reduced the migration and invasion of MDA-MB 231 malignant cells compared to sham exposure, according to the results of the scratch test and the Transwell invasion test. The mRNA and protein expression levels of E-cadherin showed an increase, while the N-cadherin expression was found with a decrease, in MDA-MB231 cells receiving 1 Hz EMF compared to sham exposure. E-cadherin's mRNA and protein expression levels were enhanced in MCF10A cells receiving 1 Hz EMF compared to sham exposure. ELF-EMF can be used as a method for the multifaceted treatments of invasive breast cancer.

The highly metastatic 4T1 breast carcinoma model possesses features of a hybrid epithelial/mesenchymal phenotype

Epithelial-mesenchymal transitions (EMTs) are thought to promote metastasis via downregulation of E-cadherin (also known as Cdh1) and upregulation of mesenchymal markers such as N-cadherin (Cdh2) and vimentin (Vim). Contrary to this, E-cadherin is retained in many invasive carcinomas and promotes collective cell invasion. To investigate how E-cadherin regulates metastasis, we examined the highly metastatic, E-cadherin-positive murine 4T1 breast cancer model, together with the less metastatic, 4T1-related cell lines 4T07, 168FARN and 67NR. We found that 4T1 cells display a hybrid epithelial/mesenchymal phenotype with co-expression of epithelial and mesenchymal markers, whereas 4T07, 168FARN, and 67NR cells display progressively more mesenchymal phenotypes in vitro that relate inversely to their metastatic capacity in vivo. Using RNA interference and constitutive expression, we demonstrate that the expression level of E-cadherin does not determine 4T1 or 4T07 cell metastatic capacity in mice. Mechanistically, 4T1 cells possess highly dynamic, unstable cell-cell junctions and can undergo collective invasion without E-cadherin downregulation. However, 4T1 orthotopic tumors in vivo also contain subregions of EMT-like loss of E-cadherin. Thus, 4T1 cells function as a model for carcinomas with a hybrid epithelial/mesenchymal phenotype that promotes invasion and metastasis.

Serpine1 mRNA confers mesenchymal characteristics to the cell and promotes CD8+ T cells exclusion from colon adenocarcinomas

Serine protease inhibitor clade E member 1 (SERPINE1) inhibits extracellular matrix proteolysis and cell detachment. However, SERPINE1 expression also promotes tumor progression and plays a crucial role in metastasis. Here, we solve this apparent paradox and report that Serpine1 mRNA per se, independent of its protein-coding function, confers mesenchymal properties to the cell, promoting migration, invasiveness, and resistance to anoikis and increasing glycolytic activity by sequestering miRNAs. Expression of Serpine1 mRNA upregulates the expression of the TRA2B splicing factor without affecting its mRNA levels. Through transcriptional profiling, we found that Serpine1 mRNA expression downregulates through TRA2B the expression of genes involved in the immune response. Analysis of human colon tumor samples showed an inverse correlation between SERPINE1 mRNA expression and CD8+ T cell infiltration, unveiling the potential value of SERPINE1 mRNA as a promising therapeutic target for colon tumors.

Spatial Engineering of Mammary Epithelial Cell Cultures with 3D Bioprinting Reveals Growth Control by Branch Point Proximity

The three-dimensional (3D) structure of the ductal epithelium and the surrounding extracellular matrix (ECM) are integral aspects of the breast tissue, and they have important roles during mammary gland development, function and malignancy. However, the architecture of the branched mammary epithelial network is poorly recapitulated in the current in vitro models. 3D bioprinting is an emerging approach to improve tissue-mimicry in cell culture. Here, we developed and optimized a protocol for 3D bioprinting of normal and cancerous mammary epithelial cells into a branched Y-shape to study the role of cell positioning in the regulation of cell proliferation and invasion. Non-cancerous cells formed continuous 3D cell networks with several organotypic features, whereas the ductal carcinoma in situ (DCIS) -like cancer cells exhibited aberrant basal polarization and defective formation of the basement membrane (BM). Quantitative analysis over time demonstrated that both normal and cancerous cells proliferate more at the branch tips compared to the trunk region of the 3D-bioprinted cultures, and particularly at the tip further away from the branch point. The location-specific rate of proliferation was independent of TGFβ signaling but invasion of the DCIS-like breast cancer cells was reduced upon the inhibition of TGFβ. Thus, our data demonstrate that the 3D-bioprinted cells can sense their position in the branched network of cells and proliferate at the tips, thus recapitulating this feature of mammary epithelial branching morphogenesis. In all, our results demonstrate the capacity of the developed 3D bioprinting method for quantitative analysis of the relationships between tissue structure and cell behavior in breast morphogenesis and cancer.

Gα12 signaling regulates transcriptional and phenotypic responses that promote glioblastoma tumor invasion

In silico interrogation of glioblastoma (GBM) in The Cancer Genome Atlas (TCGA) revealed upregulation of GNA12 (Gα12), encoding the alpha subunit of the heterotrimeric G-protein G12, concomitant with overexpression of multiple G-protein coupled receptors (GPCRs) that signal through Gα12. Glioma stem cell lines from patient-derived xenografts also showed elevated levels of Gα12. Knockdown (KD) of Gα12 was carried out in two different human GBM stem cell (GSC) lines. Tumors generated in vivo by orthotopic injection of Gα12KD GSC cells showed reduced invasiveness, without apparent changes in tumor size or survival relative to control GSC tumor-bearing mice. Transcriptional profiling of GSC-23 cell tumors revealed significant differences between WT and Gα12KD tumors including reduced expression of genes associated with the extracellular matrix, as well as decreased expression of stem cell genes and increased expression of several proneural genes. Thrombospondin-1 (THBS1), one of the genes most repressed by Gα12 knockdown, was shown to be required for Gα12-mediated cell migration in vitro and for in vivo tumor invasion. Chemogenetic activation of GSC-23 cells harboring a Gα12-coupled DREADD also increased THBS1 expression and in vitro invasion. Collectively, our findings implicate Gα12 signaling in regulation of transcriptional reprogramming that promotes invasiveness, highlighting this as a potential signaling node for therapeutic intervention.

E-cadherin Expression in Premalignant Lesions, Premalignant Conditions, Oral Squamous Cell Carcinoma, and Normal Mucosa: An Immunohistochemical Study

Background Oral squamous cell carcinoma (OSCC) is a multi-step process. Epithelial-mesenchymal transition (EMT) is an important step in the progression of OSCC. One of the components that influence EMT is E-cadherin. The aim of this study was to determine the expression of E-cadherin in oral submucous fibrosis (OSMF), various grades of epithelial dysplasia, OSCC, and to compare it with the expression in the normal mucosa. Material and methods E-cadherin immunohistochemical detection was done using a monoclonal antibody of clone EP-6TM and the PolyExcel HRP/DAB chromogen detection system. A total of 100 samples, were divided into four groups, which included epithelial dysplasia (group 2) (30 cases), oral submucous fibrosis (group 3) (OSMF-30 cases), and oral squamous cell carcinoma (group 4) (OSCC-30 cases), which was compared with normal mucosa (group 1) (10 cases). The positive control used for E-cadherin was ductal breast carcinoma. Results All the cases of normal mucosa, epithelial dysplasia, and OSMF showed positivity for E-cadherin expression. In OSCC, 97% of cases expressed E-cadherin except one case. Out of 30 cases of epithelial dysplasia, 53% of mild epithelial dysplasia had a moderate intensity of expression and 75% had a mild intensity of E-cadherin expression. In moderately differentiated OSCC, 82% of cases showed mild intensity. Tissue localization of the E-cadherin stain in the basal layer decreased from normal mucosa to grades of epithelial dysplasia and OSCC. The pattern of E-cadherin staining in all the cases of group I, group II, and group III was membranous. In 97% of OSCC cases, both membranous and cytoplasmic staining were seen. Conclusion E-cadherin expression was reduced in increasing grades of epithelial dysplasia, OSCC, and OSMF compared to that of normal mucosa. E-cadherin expression is reduced as the lesions progress to malignancy. Hence, E-cadherin can be considered a surrogate marker of malignancy.

Cadherin switching in oral squamous cell carcinoma: A clinicopathological study

Background and aim

Oral squamous cell carcinoma (OSCC) is one of the most common malignancies worldwide as it represents the sixth most common cancer. Numerous molecular mechanisms have been explained to regulate OSCC progression, including epithelial-mesenchymal transition (EMT). Cadherin switching is the pivotal process that controls EMT in which E-cadherin reduces while N-cadherin elevates. This work aimed to clarify the role of cadherin switching in OSCC.

Material and methods

Thirty paraffin-embedded tissue blocks of OSCC including six cases with lymph node metastasis were subjected to immunohistochemical staining using antibodies against E&N-cadherins. Cell cultures were performed using OSCC cell lines (SCC-15/SCC-25) from the human tongue. F-12K medium (Kaighn's Modification of Ham's F12 Medium) was added as EMT inducing media. E&N-cadherin mRNA gene expression levels were detected by real time-polymerase chain reaction (RT-PCR).

Results

Cadherin switching through N-cadherin elevation and E-cadherin reduction was evaluated at the histopathologic level in primary and metastatic OSCC as well as at the genetic level within OSCC cell culture. Cadherin switching showed a significant correlation between E&N-cadherins at different histopathological grades of OSCC and in metastatic OSCC. Moreover, the level of mRNA gene expression of E&N-cadherins in human 15 SCC and 25 SCC cell lines with EMT-inducing media exhibited a significant correlation.

Conclusions

Cadherin switching is a crucial event in the EMT process. It may be used as a significant tool in the study of OSCC progression. Cadherin switching plays a significant role in the invasion and metastasis of OSCC.

ADP Ribosylation Factor 6 Relieves Airway Inflammation and Remodeling by Inhibiting Ovalbumin Induced-Epithelial Mesenchymal Transition in Experimental Asthma, Possibly by Regulating of E2F Transcription Factor 8

BACKGROUND

Childhood asthma is a major global health concern. ADP-ribosylation factor 6 (ARF6) is a low-molecular-weight GTPase; however, its role in childhood asthma remains unclear.

METHODS

Ovalbumin (OVA)-challenged neonatal mice and transforming growth factor-β1 (TGF-β1)-induced BEAS-2B cells were used as in vivo and in vitro models of childhood asthma, respectively.

RESULTS

Upon OVA stimulation, ARF6 expression was upregulated in the lung tissue. Neonatal mice administered SehinH3 (an ARF6 inhibitor) exhibited improved pulmonary pathological injury, along with reduced inflammatory cell infiltration in the lungs and cytokine release in bronchial alveolar lavage fluid and serum (interleukin [IL]-3, IL-5, IL-13, IgE, and OVA-specific IgE). SehinH3 treatment restrained epithelial - mesenchymal transition (EMT) in the lungs of asthmatic mice, as evidenced by increased E-cadherin and decreased N-cadherin and α-smooth muscle actin expression. Different TGF-β1 exposures to BEAS-2B cells induced a time- and dose-dependent increase in ARF6 expression in vitro. Upon TGF-β1 stimulation, ARF6 knockdown repressed EMT and SehinH3 treatment caused similar results in BEAS-2B cells. The transcription factor E2F8 is involved in diverse biological functions and its increased expression was confirmed in vivo and in vitro. Dual-luciferase assays confirmed that E2F8 binds to the ARF6 promoter and promotes its transcriptional activity. In vitro results revealed that E2F8 silencing suppressed EMT, whereas rescue experiments showed that ARF6 overexpression partly reversed these phenomena.

CONCLUSION

Our study showed that ARF6 is associated with childhood asthma progression and may be positively regulated by E2F8. These results provide insight into the pathogenesis and treatment of childhood asthma.

A CRISPR/Cas9-Based Assay for High-Throughput Studies of Cancer-Induced Innervation

The aggressive nature of certain cancers and their adverse effects on patient outcomes have been linked to cancer innervation, where neurons infiltrate and differentiate within the cancer stroma. Recently we demonstrated how cancer plasticity and TGFβ signaling could promote breast cancer innervation that is associated with increased cancer aggressivity. Despite the promising potential of cancer innervation as a target for anti-cancer therapies, there is currently a significant lack of effective methods to study cancer-induced neuronal differentiation, hindering the development of high-throughput approaches for identifying new targets or pharmacological inhibitors against cancer innervation. To overcome this challenge, we used CRISPR-based endogenous labeling of the neuronal marker β3-tubulin in neuronal precursors to investigate cancer-induced neuronal differentiation in nerve-cancer cocultures and provide a tool that allows for better standardization and reproducibility of studies about cancer-induced innervation. Our approach demonstrated that β3-tubulin gene editing did not affect neuronal behavior and enabled accurate reporting of cancer-induced neuronal differentiation dynamics in high-throughput settings, which makes this approach suitable for screening large cohorts of cells or testing various biological contexts. In a more context-based approach, by combining this method with a cell model of breast cancer epithelial-mesenchymal transition, we revealed the role of cancer cell plasticity in promoting neuronal differentiation, suggesting that cancer innervation represents an underexplored path for epithelial-mesenchymal transition-mediated cancer aggressivity.

Heterogeneity and plasticity of epithelial-mesenchymal transition (EMT) in cancer metastasis: Focusing on partial EMT and regulatory mechanisms

Epithelial-mesenchymal transition (EMT) or mesenchymal-epithelial transition (MET) plays critical roles in cancer metastasis. Recent studies, especially those based on single-cell sequencing, have revealed that EMT is not a binary process, but a heterogeneous and dynamic disposition with intermediary or partial EMT states. Multiple double-negative feedback loops involved by EMT-related transcription factors (EMT-TFs) have been identified. These feedback loops between EMT drivers and MET drivers finely regulate the EMT transition state of the cell. In this review, the general characteristics, biomarkers and molecular mechanisms of different EMT transition states were summarized. We additionally discussed the direct and indirect roles of EMT transition state in tumour metastasis. More importantly, this article provides direct evidence that the heterogeneity of EMT is closely related to the poor prognosis in gastric cancer. Notably, a seesaw model was proposed to explain how tumour cells regulate themselves to remain in specific EMT transition states, including epithelial state, hybrid/intermediate state and mesenchymal state. Additionally, this article also provides a review of the current status, limitations and future perspectives of EMT signalling in clinical applications.

Fibroblast-derived conditioned media promotes lung cancer progression

Lung cancer is the leading cause of cancer death in men and women in the United States. Recent studies have implicated the tumor microenvironment as a new chemotherapeutic target by demonstrating the importance of tumor cell-stromal interactions in cancer progression. However, the exact mechanisms by which tumor cell-stromal interactions drive lung cancer progression remain undefined, particularly in the lung. We suspect host fibroblasts represent an important component of the tumor microenvironment that drives tumor progression. We found that human non-small cell lung carcinoma cell lines show alterations in cell morphology, proliferation, migration, and colony formation on soft agar when exposed to fibroblast-conditioned media (FCM). Interestingly, FCM also promoted tumor cell resistance to cisplatin-induced apoptosis. These effects varied depending on the cancer cell line used. Similar observations were made when exposing murine Lewis Lung Carcinoma cells to conditioned media harvested from primary murine lung fibroblasts. Certain effects of FCM, but not all, could be prevented by using a cMET inhibitor. In vivo, we observed enhanced growth of the primary tumors when treated with FCM, but no changes in metastatic behavior. Although the identity of the stimulating agent(s) in the fibroblast-conditioned media was not unveiled, further studies revealed that the activity is more than one factor with a high-molecular weight (over 100 kDa). These studies implicate lung fibroblast-derived factors in lung cancer progression. These data suggest that targeting the lung tumor stroma alone, or in combination with other interventions, is a promising concept that warrants further study in the setting of lung cancer.

Cell density modulates chemoresistance in breast cancer cells through differential expression of ABC transporters

BACKGROUND

Breast cancer patients undergoing chemotherapy encounter a significant challenge of chemoresistance because of drug efflux by ATP-binding cassette (ABC) transporters. Breast cancer cell density alters considerably throughout the early stages of primary and secondary tumor development. Although cell density in culture influences kinetics, the effects of varying cell densities on the chemoresistance of breast cancer cells remains largely unexplored.

METHODS AND RESULTS

We observed chemotherapeutics-induced differential gene and protein expression of ABC transporters in luminal and basal breast cancer cells cultured at low and high seeding densities. Low-density cultures depicted a significant increase in the mRNA expression of ABC transporters-ABCG2, ABCG1, ABCC4, ABCA2, ABCA3, ABCC2, ABCC3, ABCC6, ABCC7, and ABCC9 as compared with high-density cultures. Next, cells at both low and high seeding densities when pre-treated with cyclosporine A (CsA), a pan-inhibitor of ABC transporters, resulted in increased sensitization to chemotherapeutics-doxorubicin and tamoxifen at markedly low IC50 concentrations suggesting the role of ABC transporters. Finally, markedly high doxorubicin-drug accumulation, significantly increased expression of N-cadherin, and a significant decrease in chemotherapeutics-induced in vitro tumorigenesis was observed in low-density seeded breast cancer cells when pre-treated with CsA suggesting ABC transporters inhibition-mediated increased efficacy of chemotherapeutics.

CONCLUSION

These findings suggest that breast cancer cells grown at low seeding density imparts chemoresistance towards doxorubicin or tamoxifen by a differential increase in the expression of ABC transporters. Thus, a combinatorial treatment strategy including ABC transporter inhibitors and chemotherapeutics can be a way forward for overcoming the breast cancer chemoresistance.

The role of activated androgen receptor in cofilin phospho-regulation depends on the molecular subtype of TNBC cell line and actin assembly dynamics

Triple negative breast cancer (TNBC) is highly metastatic and of poor prognosis. Metastasis involves coordinated actin filament dynamics mediated by cofilin and associated proteins. Activated androgen receptor (AR) is believed to contribute to TNBC tumorigenesis. Our current work studied roles of activated AR and cofilin phospho-regulation during migration of three AR+ TNBC cell lines to determine if altered cofilin regulation can explain their migratory differences. Untreated or AR agonist-treated BT549, MDA-MB-453, and SUM159PT cells were compared to cells silenced for cofilin (KD) or AR expression/function (bicalutamide). Cofilin-1 was found to be the only ADF/cofilin isoform expressed in each TNBC line. Despite a significant increase in cofilin kinase caused by androgens, the ratio of cofilin:p-cofilin (1:1) did not change in SUM159PT cells. BT549 and MDA-MB-453 cells contain high p-cofilin levels which underwent androgen-induced dephosphorylation through increased cofilin phosphatase expression, but surprisingly maintain a leading-edge with high p-cofilin/total cofilin not found in SUM159PT cells. Androgens enhanced cell polarization in all lines, stimulated wound healing and transwell migration rates and increased N/E-cadherin mRNA ratios while reducing cell adhesion in BT549 and MDA-MB-453 cells. Cofilin KD negated androgen effects in MDA-MB-453 except for cell adhesion, while in BT549 cells it abrogated androgen-reduced cell adhesion. In SUM159PT cells, cofilin KD with and without androgens had similar effects in almost all processes studied. AR dependency of the processes were confirmed. In conclusion, cofilin regulation downstream of active AR is dependent on which actin-mediated process is being examined in addition to being cell line-specific. Although MDA-MB-453 cells demonstrated some control of cofilin through an AR-dependent mechanism, other AR-dependent pathways need to be further studied. Non-cofilin-dependent mechanisms that modulate migration of SUM159PT cells need to be investigated. Categorizing TNBC behavior as AR responsive and/or cofilin dependent can inform on decisions for therapeutic treatment.

MST4: A Potential Oncogene and Therapeutic Target in Breast Cancer

The mammalian STE 20-like protein kinase 4 (MST4) gene is highly expressed in several cancer types, but little is known about the role of MST4 in breast cancer, and the function of MST4 during epithelial-mesenchymal transition (EMT) has not been fully elucidated. Here we report that overexpression of MST4 in breast cancer results in enhanced cell growth, migration, and invasion, whereas inhibition of MST4 expression significantly attenuates these properties. Further study shows that MST4 promotes EMT by activating Akt and its downstream signaling molecules such as E-cadherin/N-cadherin, Snail, and Slug. MST4 also activates AKT and its downstream pro-survival pathway. Furthermore, by analyzing breast cancer patient tissue microarray and silicon datasets, we found that MST4 expression is much higher in breast tumor tissue compared to normal tissue, and significantly correlates with cancer stage, lymph node metastasis and a poor overall survival rate (p < 0.05). Taken together, our findings demonstrate the oncogenic potential of MST4 in breast cancer, highlighting its role in cancer cell proliferation, migration/invasion, survival, and EMT, suggesting a possibility that MST4 may serve as a novel therapeutic target for breast cancer.

An optimized MNK1b aptamer, apMNKQ2, and its potential use as a therapeutic agent in breast cancer

Breast cancer is the most commonly diagnosed and leading cause of cancer death among women worldwide. Mitogen-activated protein kinase-interacting kinases (MNKs) promote the expression of several oncogenic proteins and are overexpressed in several types of cancer. In human cells, there are four isoforms of MNKs. The truncated isoform MNK1b, first described in our laboratory, has a higher basal activity and is constitutively active. Aptamers are emerging in recent years as potential therapeutic agents that show significant advantages over drugs of other nature. We have previously obtained and characterized a highly specific aptamer against MNK1b, named apMNK2F, with a dissociation constant in the nanomolar range, which produces significant inhibition of proliferation, migration, and colony formation in breast cancer cells. Furthermore, its sequence analysis predicted two G-quadruplex structures. In this work, we show the optimization process of the aptamer to reduce its size, improving its stability. The obtained aptamer, named apMNKQ2, is able to inhibit proliferation, colony formation, migration, and invasion in breast cancer cells. In murine models of breast cancer, apMNKQ2 has demonstrated its efficacy in reducing tumor volume and the number of metastases. In conclusion, apMNKQ2 could be used as an anti-tumor drug in the future.

Substrate stiffness effect on molecular crosstalk of epithelial-mesenchymal transition mediators of human glioblastoma cells

The complexity of the microenvironment effects on cell response, show accumulating evidence that glioblastoma (GBM) migration and invasiveness are influenced by the mechanical rigidity of their surroundings. The epithelial–mesenchymal transition (EMT) is a well-recognized driving force of the invasive behavior of cancer. However, the primary mechanisms of EMT initiation and progression remain unclear. We have previously showed that certain substrate stiffness can selectively stimulate human GBM U251-MG and GL15 glioblastoma cell lines motility. The present study unifies several known EMT mediators to uncover the reason of the regulation and response to these stiffnesses. Our results revealed that changing the rigidity of the mechanical environment tuned the response of both cell lines through change in morphological features, epithelial-mesenchymal markers (E-, N-Cadherin), EGFR and ROS expressions in an interrelated manner. Specifically, a stiffer microenvironment induced a mesenchymal cell shape, a more fragmented morphology, higher intracellular cytosolic ROS expression and lower mitochondrial ROS. Finally, we observed that cells more motile showed a more depolarized mitochondrial membrane potential. Unravelling the process that regulates GBM cells’ infiltrative behavior could provide new opportunities for identification of new targets and less invasive approaches for treatment.

TGFβ1-Pretreated Exosomes of Wharton Jelly Mesenchymal Stem Cell as a Therapeutic Strategy for Improving Liver Fibrosis

Background: Mesenchymal stem cells (MSCs) are the most promising tools for cell treatment and human tissue regeneration, e.g., in liver fibrosis. Mesenchymal stem cells repair tissue damage through paracrine mediators such as exosomes. Types and concentrations of inflammatory mediators, including transforming growth factor-beta (TGFβ1), in MSCs microenvironment can affect MSCs’ function and therapeutic potency. Objectives: This experimental study aimed to explore the effects of Wharton jelly MSCs (WJ-MSCs) exosomes on fibrotic gene expression and Smad2/3 phosphorylation (phospho-Smad2/3 (p-Smad2/3)). Moreover, we further investigated whether WJ-MSCs pretreatment with different concentrations of TGFβ1 changes the anti-fibrotic properties of their exosomes. Methods: After isolation from the umbilical cord, WJ-MSCs were characterized by observing differentiation and measuring surface biomarkers using flowcytometry. The WJ-MSC-derived exosomes were extracted and identified using transmission electron microscopy (TEM), dynamic light scattering (DLS), and western blotting. Real-time PCR and western blot for extracellular matrix (ECM) and p-Smad2/3 expression detection were used to investigate the effect of exosomes from untreated and TGFβ1-pretreated WJ-MSCs on activated hepatic stellate cells (HSCs). Results: Phospho-Smad2/3, α-smooth muscle actin (α-SMA), and collagen1α1 levels were enhanced following treatment with TGFβ1, whereas E-cadherin was decreased. However, the outcomes were reversed after treatment with WJ-MSC-derived exosomes. Exosomes from TGFβ1-pretreated WJ-MSCs induced a significant decrease in p-Smad2/3 levels in activated HSCs, accompanied by the upregulation of E-cadherin gene expression and downregulation of α-SMA and collagen1α1 when compared to untreated WJ-MSC-derived exosomes. The p-Smad2/3 proteins were significantly decreased (fold change: 0.23, P-value < 0.0001) after exposure to low-dose TGFβ1-pretreated WJ-MSC-derived exosomes (0.1 ng/mL), showing the best effect on activated HSCs. Conclusions: Exosomes derived from untreated WJ-MSCs could regress TGFβ-Smad2/3 signaling and the expression of fibrotic markers in activated LX-2 cells. However, these effects were significantly profound with applying exosomes derived from 0.1 ng/mL TGFβ-pretreated WJ-MSCs. We also observed the dose-response effects of TGFβ on WJ-MSCs-derived exosomes. Therefore, exosomes derived from TGFβ-pretreated WJ-MSCs may be critical in improving fibrosis and benefit liver fibrosis patients.

EGF/EGFR Promotes Salivary Adenoid Cystic Carcinoma Cell Malignant Neural Invasion via Activation of PI3K/AKT and MEK/ERK Signaling

BACKGROUND

Salivary adenoid cystic carcinoma (SACC) is one of the most common malignant cancers of the salivary gland, and 32.4-72.0% of SACC cases exhibit neural invasion (NI), however, the molecular mechanism underlying the high invasion potential of SACC remains unclear.

METHODS

The present study investigated the role of epidermal growth factor receptor (EGFR) in the AKT inhibition- or mitogen-activated protein kinase kinase (MEK)-induced NI and epithelial-mesenchymal transition (EMT) in SACC cells using EGFR, PI3K and MEK inhibitors. SACC 83 cell viability was assessed using an MTT assay, and a wound healing assay was performed to evaluate cell migration. Immunohistochemical staining with streptavidin peroxidase was used to detect the positive expression rate of EMT, AKT, phosphorylated (p)-AKT, ERK and p-ERK proteins. The impact of EGFR, PI3K and MEK inhibitors on tumor growth and NI was examined in a xenograft model in nude mice.

RESULTS

EGF and EGFR are effective in increasing cell viability, migration and invasion. SACC metastasis is affected by the PI3K/AKT and MEK/ERK pathways, both of which are initiated by EGF/EGFR. The EMT and NI are regulated by the EGF/EGFR, PI3K/AKT and MEK/ERK pathways. The present findings demonstrate the importance of suppressed EGFR/AKT/MEK signaling in NI in SACC by neural-tumor co-culture in vitro. Furthermore, our preclinical experiment provides solid evidence that injection of EGFR, PI3K and MEK inhibitors obviously suppressed the tumor growth and NI of SACC cells in nude mice.

CONCLUSION

It was identified that inhibitors of EGFR, PI3K/AKT or MEK/ERK suppressed the proliferation, migration and NI of SACC-83 cells via downregulation of the PI3K/AKT or MEK/ERK pathways. It was also demonstrated that inhibition of EGFR abolishes EMT in SACC by inhibiting the signaling of PI3K/AKT and MEK/ERK. The present results suggest the potential effectiveness of targeting multiple oncogenes associated with downstream pathways of EGF/EGFR, as well as potential therapeutic targets to limit NI in SACC by PI3K/AKT or MEK/ERK inhibition.

Vestigial-like family member 3 stimulates cell motility by inducing high-mobility group AT-hook 2 expression in cancer cells

Vestigial‐like family member 3 (VGLL3) is a cofactor for TEA domain transcription factors (TEADs). Although VGLL3 is known to be highly expressed and stimulate cell proliferation in mesenchymal cancer cells, its involvement in mesenchymal phenotypes is largely unknown. In this study, we found that VGLL3 promotes epithelial‐to‐mesenchymal transition (EMT)‐like phenotypic changes. We found that A549 human lung cancer cells stably expressing VGLL3 exhibit spindle‐like morphological changes, reduction in the epithelial marker E‐cadherin and induction of the mesenchymal marker Snail. Notably, VGLL3‐expressing cells exhibited enhanced motility. The DNA‐binding protein high‐mobility group AT‐hook 2 (HMGA2) was found to be a target of the VGLL3‐TEAD4 complex, and HMGA2 knockdown repressed EMT‐like phenotypic changes in VGLL3‐expressing cells. VGLL3‐dependent phenotypic changes are involved in transforming growth factor‐β (TGF‐β)‐induced EMT progression. VGLL3 or HMGA2 knockdown repressed the motility of the mesenchymal breast cancer MDA‐MB‐231 cells. Importantly, high levels of VGLL3 expression were shown to have a positive correlation with poor prognosis in various human cancers, such as breast, colon, ovarian, head and neck, pancreatic, renal, gastric and cervical cancers. These results suggest that VGLL3 promotes EMT‐like cell motility by inducing HMGA2 expression and accelerates cancer progression.

Pigment Epithelia of the Eye: Cell-Type Conversion in Regeneration and Disease

Pigment epithelial cells (PECs) of the retina (RPE), ciliary body, and iris (IPE) are capable of altering their phenotype. The main pathway of phenotypic switching of eye PECs in vertebrates and humans in vivo and/or in vitro is neural/retinal. Besides, cells of amphibian IPE give rise to the lens and its derivatives, while mammalian and human RPE can be converted along the mesenchymal pathway. The PECs’ capability of conversion in vivo underlies the lens and retinal regeneration in lower vertebrates and retinal diseases such as proliferative vitreoretinopathy and fibrosis in mammals and humans. The present review considers these processes studied in vitro and in vivo in animal models and in humans. The molecular basis of conversion strategies in PECs is elucidated. Being predetermined onto- and phylogenetically, it includes a species-specific molecular context, differential expression of transcription factors, signaling pathways, and epigenomic changes. The accumulated knowledge regarding the mechanisms of PECs phenotypic switching allows the development of approaches to specified conversion for many purposes: obtaining cells for transplantation, creating conditions to stimulate natural regeneration of the retina and the lens, blocking undesirable conversions associated with eye pathology, and finding molecular markers of pathology to be targets of therapy.

Cell monolayer deformation microscopy reveals mechanical fragility of cell monolayers following EMT

Tissue and cell mechanics are crucial factors in maintaining homeostasis and in development, with aberrant mechanics contributing to many diseases. During the epithelial-to-mesenchymal transition (EMT), a highly conserved cellular program in organismal development and cancer metastasis, cells gain the ability to detach from their original location and autonomously migrate. While a great deal of biochemical and biophysical changes at the single-cell level have been revealed, how the physical properties of multicellular assemblies change during EMT, and how this may affect disease progression, is unknown. Here we introduce cell monolayer deformation microscopy (CMDM), a new methodology to measure the planar mechanical properties of cell monolayers by locally applying strain and measuring their resistance to deformation. We employ this new method to characterize epithelial multicellular mechanics at early and late stages of EMT, finding the epithelial monolayers to be relatively compliant, ductile, and mechanically homogeneous. By comparison, the transformed mesenchymal monolayers, while much stiffer, were also more brittle, mechanically heterogeneous, displayed more viscoelastic creep, and showed sharp yield points at significantly lower strains. Here, CMDM measurements identify specific biophysical functional states of EMT and offer insight into how cell aggregates fragment under mechanical stress. This mechanical fingerprinting of multicellular assemblies using new quantitative metrics may also offer new diagnostic applications in healthcare to characterize multicellular mechanical changes in disease.

CDH18 is a fetal epicardial biomarker regulating differentiation towards vascular smooth muscle cells

The epicardium is a mesothelial layer covering the myocardium serving as a progenitor source during cardiac development. The epicardium reactivates upon cardiac injury supporting cardiac repair and regeneration. Fine-tuned balanced signaling regulates cell plasticity and cell-fate decisions of epicardial-derived cells (EPCDs) via epicardial-to-mesenchymal transition (EMT). However, powerful tools to investigate epicardial function, including markers with pivotal roles in developmental signaling, are still lacking. Here, we recapitulated epicardiogenesis using human induced pluripotent stem cells (hiPSCs) and identified type II classical cadherin CDH18 as a biomarker defining lineage specification in human active epicardium. The loss of CDH18 led to the onset of EMT and specific differentiation towards cardiac smooth muscle cells. Furthermore, GATA4 regulated epicardial CDH18 expression. These results highlight the importance of tracing CDH18 expression in hiPSC-derived epicardial cells, providing a model for investigating epicardial function in human development and disease and enabling new possibilities for regenerative medicine.

Probing TGF-β1-induced cytoskeletal rearrangement by fluorescent-labeled silica nanoparticle uptake assay

Cytoskeletal proteins are essential in maintaining cell morphology, proliferation, and viability as well as internalizing molecules in phagocytic and non-phagocytic cells. Orderly aligned cytoskeletons are disturbed by a range of biological processes, such as the epithelial-mesenchymal transition, which is observed in cancer metastasis. Although many biological methods have been developed to detect cytoskeletal rearrangement, simple and quantitative in vitro approaches are still in great demand. Herein, we applied a flow cytometry-based nanoparticle uptake assay to measure the degree of cytoskeletal rearrangement induced by transforming growth factor β1 (TGF-β1). For the assay, silica nanoparticles, selected for their high biocompatibility, were fluorescent-labeled to facilitate quantification with flow cytometry. Human keratinocyte HaCaT cells were treated with different concentrations of TGF-β1 and then exposed to FITC-labeled silica nanoparticles. Increasing concentrations of TGF-β1 induced gradual changes in cytoskeletal rearrangement, as confirmed by conventional assays. The level of nanoparticle uptake increased by TGF-β1 treatment in a dose-dependent manner, indicating that our nanoparticle uptake assay can be used as a quick and non-destructive approach to measure cytoskeletal rearrangement.

The long non-coding RNA ET-20 mediates EMT by impairing desmosomes in breast cancer cells

The vast majority of breast cancer-associated deaths are due to metastatic spread of cancer cells, a process aided by epithelial-to-mesenchymal transition (EMT). Mounting evidence has indicated that long non-coding RNAs (lncRNAs) also contribute to tumor progression. We report the identification of 114 novel lncRNAs that change their expression during TGFβ-induced EMT in murine breast cancer cells (referred to as EMT-associated transcripts; ETs). Of these, the ET-20 gene localizes in antisense orientation within the tenascin C (Tnc) gene locus. TNC is an extracellular matrix protein that is critical for EMT and metastasis formation. Both ET-20 and Tnc are regulated by the EMT master transcription factor Sox4. Notably, ablation of ET-20 lncRNA effectively blocks Tnc expression and with it EMT. Mechanistically, ET-20 interacts with desmosomal proteins, thereby impairing epithelial desmosomes and promoting EMT. A short transcript variant of ET-20 is shown to be upregulated in invasive human breast cancer cell lines, where it also promotes EMT. Targeting ET-20 appears to be a therapeutically attractive lead to restrain EMT and breast cancer metastasis in addition to its potential utility as a biomarker for invasive breast cancer.

Mnt Represses Epithelial Identity To Promote Epithelial-to-Mesenchymal Transition

The multistep process of epithelial-to-mesenchymal transition (EMT), whereby static epithelial cells become migratory mesenchymal cells, plays a critical role during various developmental contexts, wound healing, and pathological conditions such as cancer metastasis. Despite the established function of basic helix-loop-helix (bHLH) transcription factors (TFs) in cell fate determination, only a few have been examined for their role in EMT. Here, using transcriptome analysis of distinct stages during stepwise progression of transforming growth factor beta (TGFβ)-induced EMT in mammary epithelial cells, we revealed distinct categories of bHLH TFs that show differential expression kinetics during EMT. Using a short interfering RNA-mediated functional screen for bHLH TFs during EMT, we found Max network transcription repressor (MNT) to be essential for EMT in mammary epithelial cells. We show that the depletion of MNT blocks TGFβ-induced morphological changes during EMT, and this is accompanied by derepression of a large number of epithelial genes. We show that MNT mediates the repression of epithelial identity genes during EMT by recruiting HDAC1 and mediating the loss of H3K27ac and chromatin accessibility. Lastly, we show that MNT is expressed at higher levels in EMT-High breast cancer cells and is required for their migration. Taken together, these findings establish MNT as a critical regulator of cell fate changes during mammary EMT. IMPORTANCE The bHLH TF Mnt promotes epithelial to mesenchymal transition through epigenetic repression of the epithelial gene expression program.

RON Mediates Tumor-Promoting Effects in Endometrial Adenocarcinoma

Endometrial adenocarcinoma is one of the most prevalent female reproductive tract cancers in the world, and the development of effective treatment is still the main goal of its current research. Epithelial-mesenchymal transition (EMT) plays a significant part in the occurrence and development of epithelial carcinoma, including endometrial adenocarcinoma. Recepteur d'origine nantais (RON) induces EMT and promotes proliferation, migration, and invasion in various epithelial-derived cancers, but its role in endometrial adenocarcinoma is still poorly studied. The purpose of this study is to verify the overexpression of RON in endometrial adenocarcinoma and to explore its specific roles. RON expression in tumor lesions was verified by immunohistochemical staining, HEC-1B cells were used to construct stable cell lines with RON overexpression or knockdown to investigate the effects of RON on the function of endometrial adenocarcinoma cells, and xenotransplantation experiment was carried out in nude mice to explore the effect of RON on the growth of endometrial adenocarcinoma in vivo. This study revealed that RON could promote the proliferation, migration, and invasion of HEC-1B cells and induce EMT, and these effects were regulated through the Smad pathway. RON overexpression could promote growth of endometrial adenocarcinoma cells in nude mice, while its inhibitor BMS777607 could restrict this role. RON played an important role in endometrial adenocarcinoma and had a potential to become a new therapeutic target for endometrial adenocarcinoma.

Antitumor Effect of Saikosaponin A on Human Neuroblastoma Cells

Objective

Neuroblastoma (NB) is a highly metastatic tumor in children that develops in the sympathetic nervous system and has a low curative rate. Saikosaponin A (SSA), an active ingredient isolated from the root of Radix Bupleuri, is a natural compound with various pharmacological activities and shows good application prospects in antitumors. This study investigated the antihuman NB activity of SSA and underlying mechanisms associated with its actions.

Materials and Methods

The MTT method was used to detect the activity of SSA in inhibiting human NB cell SK-N-AS proliferation. Cell morphology was observed. The flow cytometry technology was used in analyzing the cell apoptosis rate. The Transwell assay evaluated cell migration and invasion following SSA treatment, apoptosis-related protein expression, and angiogenesis-related protein expression, and EMT-related proteins were detected by western blot analysis.

Results

SSA showed an inhibitory effect on SK-N-AS cells with the IC₅₀ values of 14.14 μM at 24 h and 12.41 μM at 48 h. Results indicated that SSA has proapoptotic activity, and its proapoptotic activity is positively correlated with the Bax/Bcl-2/caspase-9/caspase-7/PARP pathway. Furthermore, SSA inhibited the invasion and migration of SK-N-AS cells via regulating the angiogenesis-related VEGFR2/Src/Akt pathway and the epithelial-mesenchymal transition- (EMT-) related protein expression.

Conclusion

SSA exerts an antihuman NB effect and thus provides foundations for NB treatment.

ARTEMIN Promotes Oncogenicity and Resistance to 5-Fluorouracil in Colorectal Carcinoma by p44/42 MAPK Dependent Expression of CDH2

ARTEMIN (ARTN), one of the glial-cell derived neurotrophic factor family of ligands, has been reported to be associated with a number of human malignancies. In this study, the enhanced expression of ARTN in colorectal carcinoma (CRC) was observed; the expression of ARTN positively correlated with lymph node metastases and advanced tumor stages and predicted poor prognosis. Forced expression of ARTN in CRC cells enhanced oncogenic behavior, mesenchymal phenotype, stem cell-like properties and tumor growth and metastasis in a xenograft model. These functions were conversely inhibited by depletion of endogenous ARTN. Forced expression of ARTN reduced the sensitivity of CRC cells to 5-FU treatment; and 5-FU resistant CRC cells harbored enhanced expression of ARTN. The oncogenic functions of ARTN were demonstrated to be mediated by p44/42 MAP kinase dependent expression of CDH2 (CADHERIN 2, also known as N-CADHERIN). Inhibition of p44/42 MAP kinase activity or siRNA mediated depletion of endogenous CDH2 reduced the enhanced oncogenicity and chemoresistance consequent to forced expression of ARTN induced cell functions; and forced expression of CDH2 rescued the reduced mesenchymal properties and resistance to 5-FU after ARTN depletion. In conclusion, ARTN may be of prognostic and theranostic utility in CRC.

Quantitative and Multiplexed Fluorescence Lifetime Imaging of Intercellular Tensile Forces

Mechanical interactions between cells have been shown to play critical roles in regulating cell signaling and communications. However, the precise measurement of intercellular forces is still quite challenging, especially considering the complex environment at cell-cell junctions. In this study, we report a fluorescence lifetime-based approach to image and quantify intercellular molecular tensions. Using this method, tensile forces among multiple ligand-receptor pairs can be measured simultaneously. We first validated our approach and developed lifetime measurement-based DNA tension probes to image E-cadherin-mediated tension on epithelial cells. These probes were then further applied to quantify the correlations between E-cadherin and N-cadherin tensions during an epithelial-mesenchymal transition process. The modular design of these probes can potentially be used to study the mechanical features of various physiological and pathological processes.

Inhibition of circRNA circVPS33B Reduces Warburg Effect and Tumor Growth Through Regulating the miR-873-5p/HNRNPK Axis in Infiltrative Gastric Cancer

BACKGROUND

Circular RNA VPS33B (circVPS33B) has been revealed to be upregulated in gastric cancer (GC) tissues. However, the role of circVPS33B in infiltrative GC is indistinct.

METHODS

Expression of circVPS33B was detected using quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, migration, and invasion of infiltrative GC cells (XGC-1) were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT), plate clone, wound-healing, or transwell assays. Protein levels were detected by Western blotting. Measurements of extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) were executed using an XF96 extracellular flux analyzer. Glucose uptake and lactate production were analyzed by glycolysis assay. The regulatory mechanism of circVPS33B had been explored by bioinformatics analysis, dual-luciferase reporter assay, and/or RNA pull-down assay. In vivo tumorigenesis assay was executed to verify the oncogenicity of circVPS33B.

RESULTS

CircVPS33B was upregulated in infiltrative GC tissues and cells. CircVPS33B silencing decreased tumor growth in vivo and inhibited proliferation, migration, invasion, EMT, and Warburg effect of infiltrative GC cells in vitro. Mechanically, circVPS33B regulated heterogeneous nuclear ribonucleoprotein K (HNRNPK) expression via sponging miR-873-5p. Furthermore, miR-873-5p inhibitor offset circVPS33B knockdown-mediated effects on malignant behaviors and Warburg effect of infiltrative GC cells. HNRNPK overexpression reversed the inhibitory impact of miR-873-5p mimic on malignant behaviors and Warburg effect of infiltrative GC cells.

CONCLUSION

CircVPS33B accelerated Warburg effect and tumor growth through regulating the miR-873-5p/HNRNPK axis in infiltrative GC, manifesting that circVPS33B might be a potential target for infiltrative GC treatment.

Identification of EMT signaling cross-talk and gene regulatory networks by single-cell RNA sequencing

The epithelial-to-mesenchymal transition (EMT) plays a critical role during normal development and in cancer progression. EMT is induced by various signaling pathways, including TGF-β, BMP, Wnt-β-catenin, NOTCH, Shh, and receptor tyrosine kinases. In this study, we performed single-cell RNA sequencing on MCF10A cells undergoing EMT by TGF-β1 stimulation. Our comprehensive analysis revealed that cells progress through EMT at different paces. Using pseudotime clustering reconstruction of gene-expression profiles during EMT, we found sequential and parallel activation of EMT signaling pathways. We also observed various transitional cellular states during EMT. We identified regulatory signaling nodes that drive EMT with the expression of important microRNAs and transcription factors. Using a random circuit perturbation methodology, we demonstrate that the NOTCH signaling pathway acts as a key driver of TGF-β-induced EMT. Furthermore, we demonstrate that the gene signatures of pseudotime clusters corresponding to the intermediate hybrid EMT state are associated with poor patient outcome. Overall, this study provides insight into context-specific drivers of cancer progression and highlights the complexities of the EMT process.

KSR1- and ERK-dependent translational regulation of the epithelial-to-mesenchymal transition

The epithelial-to-mesenchymal transition (EMT) is considered a transcriptional process that induces a switch in cells from a polarized state to a migratory phenotype. Here, we show that KSR1 and ERK promote EMT-like phenotype through the preferential translation of Epithelial-Stromal Interaction 1 (EPSTI1), which is required to induce the switch from E- to N-cadherin and coordinate migratory and invasive behavior. EPSTI1 is overexpressed in human colorectal cancer (CRC) cells. Disruption of KSR1 or EPSTI1 significantly impairs cell migration and invasion in vitro, and reverses EMT-like phenotype, in part, by decreasing the expression of N-cadherin and the transcriptional repressors of E-cadherin expression, ZEB1 and Slug. In CRC cells lacking KSR1, ectopic EPSTI1 expression restored the E- to N-cadherin switch, migration, invasion, and anchorage-independent growth. KSR1-dependent induction of EMT-like phenotype via selective translation of mRNAs reveals its underappreciated role in remodeling the translational landscape of CRC cells to promote their migratory and invasive behavior.

The oncogenic E3 ligase TRIP12 suppresses epithelial-mesenchymal transition (EMT) and mesenchymal traits through ZEB1/2

Thyroid hormone receptor interactor 12 (TRIP12) is an E3 ligase most notably involved in the proteolytic degradation of the tumor suppressor p14ARF. Through this process, it is proposed that TRIP12 plays an oncogenic role in tumor initiation and growth. However, its role in other cancer processes is unknown. In this study, using publicly available cancer patient datasets, we found TRIP12 to be associated with distant metastasis-free survival in breast cancer, suggesting an inhibitory role in metastasis. Following TRIP12 depletion, an epithelial-mesenchymal transition (EMT) shift occurred with concomitant changes in EMT cell adhesion markers identified through RNA-seq. In line with EMT changes, TRIP12-depleted cells gained mesenchymal traits such as loss of cell polarity, dislodgement from bulk cells at a higher frequency, and increased cellular motility. Furthermore, ectopic TRIP12 expression sensitized cells to anoikis. Mechanistically, TRIP12 suppresses EMT through inhibiting ZEB1/2 gene expression, and ZEB1/2 depletion rescues EMT markers and mesenchymal behavior. Overall, our study delineates TRIP12's role in inhibition of EMT and implies a potential suppressive role in breast cancer metastasis.

Transcriptome Landscape of Epithelial to Mesenchymal Transition of Human Stem Cell-Derived RPE

Purpose

RPE injury often induces epithelial to mesenchymal transition (EMT). Although RPE-EMT has been implicated in a variety of retinal diseases, including proliferative vitroretinopathy, neovascular and atrophic AMD, and diabetic retinopathy, it is not well-understood at the molecular level. To contribute to our understanding of EMT in human RPE, we performed a time-course transcriptomic analysis of human stem cell-derived RPE (hRPE) monolayers induced to undergo EMT using 2 independent, yet complementary, model systems.

Methods

EMT of human stem cell-derived RPE monolayers was induced by either enzymatic dissociation or modulation of TGF-β signaling. Transcriptomic analysis of cells at different stages of EMT was performed by RNA-sequencing, and select findings were confirmed by reverse transcription quantitative PCR and immunostaining. An ingenuity pathway analysis (IPA) was performed to identify signaling pathways and regulatory networks associated with EMT.

Results

Proteocollagenolytic enzymatic dissociation and cotreatment with TGF-β and TNF-α both induce EMT in human stem cell-derived RPE monolayers, leading to an increased expression of mesenchymal factors and a decreased expression of RPE differentiation-associated factors. Ingenuity pathway analysis identified the upstream regulators of the RPE-EMT regulatory networks and identified master switches and nodes during RPE-EMT. Of particular interest was the identification of widespread dysregulation of axon guidance molecules during RPE-EMT progression.

Conclusions

The temporal transcriptome profiles described here provide a comprehensive resource of the dynamic signaling events and the associated biological pathways that underlie RPE-EMT onset. The pathways defined by these studies may help to identify targets for the development of novel therapeutic targets for the treatment of retinal disease.

MicroRNA Signature of Epithelial-Mesenchymal Transition in Group B Streptococcal Infection of the Placental Chorioamniotic Membranes

BACKGROUND

Infection-induced preterm birth is a major cause of neonatal mortality and morbidity and leads to preterm premature rupture of placental chorioamniotic membranes. The loss of amniotic epithelial cells and tensile strength preceding membrane rupture is poorly understood. We hypothesized that intrauterine bacterial infection induces changes in microRNA (miRNA) expression, leading to amniotic epithelial cell loss and membrane weakening.

METHODS

Ten pregnant pigtail macaques received choriodecidual inoculation of either group B Streptococcus (GBS) or saline (n = 5/group). Placental chorioamniotic membranes were studied using RNA microarray and immunohistochemistry. Chorioamniotic membranes from women with preterm premature rupture of membranes (pPROM) and normal term pregnancies were studied using transmission electron microscopy.

RESULTS

In our model, an experimental GBS infection was associated with changes in the miRNA profile in the chorioamniotic membranes consistent with epithelial to mesenchymal transition (EMT) with loss of epithelial (E-cadherin) and gain of mesenchymal (vimentin) markers. Similarly, loss of desmosomes (intercellular junctions) was seen in placental tissues from women with pPROM.

CONCLUSIONS

We describe EMT as a novel mechanism for infection-associated chorioamniotic membrane weakening, which may be a common pathway for many etiologies of pPROM. Therapy based on anti-miRNA targeting of EMT may prevent pPROM due to perinatal infection.

Hepatitis B virus core protein promotes the expression of neuraminidase 1 to facilitate hepatocarcinogenesis

Neuraminidase 1 (NEU1) has been reported to be associated with hepatocellular carcinoma (HCC). However, the function and associated molecular mechanisms of NEU1 in hepatitis B virus (HBV)-related HCC have not been well investigated. In the present study, the expression of NEU1 mediated by HBV and HBV core protein (HBc) was measured in hepatoma cells. The expression of NEU1 protein was detected via immunohistochemical analysis in HBV-associated HCC tissues. The role of NEU1 in the activation of signaling pathways and epithelial-mesenchymal transition (EMT) and the proliferation and migration of hepatoma cells mediated by HBc was assessed. We found that NEU1 was upregulated in HBV-positive hepatoma cells and HBV-related HCC tissues. HBV promoted NEU1 expression at the mRNA and protein level via HBc in hepatoma cells. Mechanistically, HBc was able to enhance the activity of the NEU1 promoter through NF-κB binding sites. In addition, through the increase in NEU1 expression, HBc contributed to activation of downstream signaling pathways and EMT in hepatoma cells. Moreover, NEU1 facilitated the proliferation and migration of hepatoma cells mediated by HBc. Taken together, our findings provide novel insight into the molecular mechanism underlying the oncogenesis mediated by HBc and demonstrate that NEU1 plays a vital role in HBc-mediated functional abnormality in HCC. Thus, NEU1 may serve as a potential therapeutic target in HBV-associated HCC.

Wound healing efficacy of Jamun honey in diabetic mice model through reepithelialization, collagen deposition and angiogenesis

Diabetic patients are frequently afflicted with impaired wound healing where linear progression of molecular and cellular events compromised. Despite of meaningful progress in diabetic treatment, management of diabetic chronic wounds is still challenging. Jamun (Syzygium cumini) honey may be a promising candidate for diabetic wound healing and need to explore in detail. So present study was designed to evaluate the efficacy of Jamun honey (JH) for diabetic wound healing in in vitro wound (primary fibroblasts) model and in in vivo of diabetic mice (Streptozotocin induced) model. The fibroblast cell model was studied for migratory behaviour and myofibrolasts infiltration under honey interventions via scratch/migration assay, immuno-cytochemistry and western blot. We applied FDA approved Manuka honey (MH) as positive control and JH as test honey to evaluate wound re-epithelialization, sub-epithelial connective tissue modification and angiogenesis via histo-pathological and immuno-histochemical analysis. JH (0.1% v/v) dilution has notably improved wound closure, migration with concomitant α-SMA expressions in vitro. Topical application of JH in diabetic mice model showed significant (*p ≤ 0.05) wound closure, reepithelialization, collagen deposition (I/III) and balanced the myofibroblasts formation. It also modulated vital angiogenic markers (viz HIF-1α, VEGF, VEGF R-II) significantly (*p ≤ 0.05). All these observations depicted that JH promotes sequential stages of wound healing in diabetic mice model. The results of the present study established Jamun honey as good as Manuka honey considering wound closure, re-epithelialization, collagen deposition and pro-angiogenic potential.

Overexpression of wild type or a Q311E mutant MB21D2 promotes a pro-oncogenic phenotype in HNSCC

Cadherin‐mediated cell–cell contacts regulated by intracellular binders play critical roles in tissue homeostasis and tumorigenesis. Here, we screened mutational profiles of 312 annotated genes involved in cadherin binding in human squamous cell carcinomas and found MB21D2 to carry a unique recurrent Q311E mutation. MB21D2 overexpression was also frequently found in head and neck cancer (HNSCC) and was associated with poor clinical outcomes. Cell‐based characterizations revealed pro‐oncogenic roles for MB21D2 wild‐type (WT) and its Q311E mutant (Q311E) in cell proliferation, colony formation, sphere growth, and migration/invasion by promoting epithelial–mesenchymal transition. Conversely, MB21D2 knockdown in MB21D2‐overexpressing cells resulted in cell growth arrest and apoptosis. Xenograft tumor models with Q311E‐expressing cells formed larger and more aggressive lesions, compared to models with WT‐MB21D2‐expressing cells or an empty vector. Transcriptome and protein interactome analyses revealed enrichment of KRAS signaling by MB21D2 expression. Immunoblotting confirmed RAS elevation, along with upregulation/phosphorylation of PI3K, AKT, and CREB. Blocking RAS signaling in MB21D2‐expressing cells by manumycin significantly reduced cell growth and survival. Our study thus defined RAS signaling‐dependent pro‐oncogenic roles for MB21D2 overexpression and Q311E MB21D2 expression in HNSCC development.

15-Deoxy-Δ12,14-prostaglandin J2 Induces Epithelial-to-mesenchymal Transition in Human Breast Cancer Cells and Promotes Fibroblast Activation

In inflammation-associated carcinogenesis, COX-2 is markedly overexpressed, resulting in accumulation of various prostaglandins. 15-deoxy-Δ^12,14-prostaglandin J₂ (15d-PGJ₂) is one of the terminal products of COX-2-catalyzed arachidonic acid catabolism with oncogenic potential. Epithelial-to-mesenchymal transition (EMT) is a process by which epithelial cells lose their polarity and adhesiveness, and thereby gain migratory and invasive properties. Treatment of human breast cancer MCF-7 cells with 15d-PGJ₂ induced EMT as evidenced by increased expression of Snail and ZEB1, with concurrent down-regulation of E-cadherin. Nuclear extract from 15d-PGJ₂-treated MCF-7 cells showed the binding of Snail and ZEB1 to E-box sequences present in the E-cadherin promoter, which accounts for repression of E-catherin expression. Unlike 15d-PGJ₂, its non-electrophilic analogue 9,10-dihydro-15d-PGJ₂ failed to induce EMT, suggesting that the α,β-unsaturated carbonyl group located in the cyclopentenone ring of 15d-PGJ₂ is essential for its oncogenic function. Notably, the mRNA level of interleukin-8 (IL-8)/CXCL8 was highly elevated in 15d-PGJ₂-stimulated MCF-7 cells. 15d-PGJ₂-induced up-regulation of IL-8/CXCL8 expression was abrogated by silencing of Snail short interfering RNA. Treatment of normal fibroblast with conditioned medium obtained from cultures of MCF-7 cells undergoing EMT induced the expression of activated fibroblast marker proteins, α-smooth muscle actin and fibroblasts activation protein-α. Co-culture of normal fibroblasts with 15d-PGJ₂-stimulated MCF-7 cells also activated normal fibroblast cells to cancer associated fibroblasts. Taken together, above findings suggest that 15d-PGJ₂ induces EMT through up-regulation of Snail expression and subsequent production of CXCL8 as a putative activator of fibroblasts, which may contribute to tumor-stroma interaction in inflammatory breast cancer microenvironment.

Exosomes: The protagonists in the tale of colorectal cancer?

Exosomes, which facilitate intercellular communication, antigen presentation and shuttling of biological agents, were initially thought as the cell's garbage cargo but today, after about 40 years of their discovery, we are now beginning to understand their potential role in diagnosis and therapy of several diseases including cancers. Various studies over the decades have signified the role of exosomes in different stages of cancer. Exosomes play a key role in colorectal cancer initiation (CRC), promotion of anti- apoptotic signaling pathways, regulating tumor microenvironment, enhancing tumorigenicity, promotion of angiogenesis, stem cell proliferation and endothelial cell migration, establishment of immune suppressive environment, formation of pre- metastatic niche and metastasis. Exosomes also elicits drug resistance. Since, they have the ability to cross the biological barrier, exosomes are now being explored as an efficient target specific drug delivery system that facilitates the shipping of different biomolecules and therapeutic drugs. However, cautious and strong investigative approaches are required before approving exosomes as therapeutics or drug delivery systems. In this review, we summarize the role of exosomes in different stages of CRC and also elaborate on the applications of exosomes in diagnosis and therapy with respect to CRC.

SIRT1-modified human umbilical cord mesenchymal stem cells ameliorate experimental peritoneal fibrosis by inhibiting the TGF-β/Smad3 pathway

Introduction

Peritoneal fibrosis is a serious complication of long-term peritoneal dialysis (PD). Combination therapies are emerging as a promising treatment for tissue damage. Here, we investigated the therapeutic potential of SIRT1-modified human umbilical cord mesenchymal stem cells (hUCMSCs) for peritoneal fibrosis.

Methods

SIRT1 was overexpressed in hUCMSCs to establish SIRT1-modified hUCMSCs. Co-culture and transplantation experiments were performed in TGF-β-stimulated Met-5A cells and peritoneal damage rodent model to assess the therapeutic potential of SIRT1-modified hUCMSCs for peritoneal fibrosis through qPCR, Western blot, and peritoneal function analyses.

Results

SIRT1-modified hUCMSC administration had more potent anti-fibrosis ability than hUCMSCs, which significantly inhibited the expression of fibrotic genes and suppressed EMT process, increased ultrafiltration volume, and restored homeostasis of bioincompatible factors in dialysis solution. Mechanistically, SIRT1-modified hUCMSCs attenuated peritoneal fibrosis through reducing peritoneal inflammation and inhibiting the TGF-β/Smad3 pathway in peritoneal omentum tissues.

Conclusion

SIRT1-modified hUCMSCs might work as a promising therapeutic strategy for the treatment of peritoneal dialysis-induced peritoneal damage and fibrosis.

CDH2/N-cadherin and early diagnosis of invasion in patients with ductal carcinoma in situ

PURPOSE

This proof-of-concept study investigates gene expression in core needle biopsies (CNB) to predict whether individuals diagnosed with ductal carcinoma in situ (DCIS) on CNB were affected by invasion at the time of diagnosis.

METHODS

Using a QuantiGene Plex 2.0 assay, 14 gene expression profiling was performed in 303 breast tissue samples. Preoperative diagnostic performance of a gene was measured by area under receiver-operating characteristic curve (AUC) with 95% confidence interval (CI). The gene mRNA positivity cutoff was computed using Gaussian mixture model (GMM); protein expression was measured by immunohistochemistry; DNA methylation was evaluated by targeted bisulfite sequencing.

RESULTS

mRNA from 69% (34/49) mammoplasties, 72% (75/104) CNB DCIS, and 89% (133/150) invasive breast cancers (IBC) were analyzed. Based on pre-and post-surgery DCIS chart reviews, 21 cases were categorized as DCIS synchronous with invasion and 54 DCIS were pure DCIS without pathologic evidence of invasive disease. The ectopic expression of neuronal cadherin CDH2 was probable in 0% mammoplasties, 6% pure DCIS, 29% synchronous DCIS, and 26% IBC. The CDH2 mRNA positivity in preoperative biopsies showing pure DCIS was predictive of a final diagnosis of invasion (AUC = 0.67; 95% CI 0.53-0.80; P = 0.029). Site-specific methylation of the CDH2 promoter (AUC = 0.76; 95% CI 0.54-0.97; P = 0.04) and measurements of N-cadherin, a pro-invasive cell-cell adhesion receptor encoded by CDH2 (AUC = 0.8; 95% CI 0.66-0.99; P < 0.005) had a discriminating power allowing for discernment of CDH2-positive biopsy.

CONCLUSIONS

Evidence of CDH2/N-cadherin expression, predictive of invasion synchronous with DCIS, may help to clarify a diagnosis and direct the course of therapy earlier in a patient's care.

A subset of activated fibroblasts is associated with distant relapse in early luminal breast cancer

Background

Early luminal breast cancer (BC) represents 70% of newly diagnosed BC cases. Among them, small (under 2 cm) BC without lymph node metastasis (classified as T1N0) have been rarely studied, as their prognosis is generally favorable. Nevertheless, up to 5% of luminal T1N0 BC patients relapse with distant metastases that ultimately prove fatal. The aim of our work was to identify the mechanisms involved in metastatic recurrence in these patients.

Methods

Our study addresses the role that autonomous and non-autonomous tumor cell features play with regard to distant recurrence in early luminal BC patients. We created a cohort of T1N0 luminal BC patients (tumors between 0.5–2 cm without lymph node metastasis) with metastatic recurrence (“cases”) and corresponding “controls” (without relapse) matched 1:1 on main prognostic factors: age, grade, and proliferation. We deciphered different characteristics of cancer cells and their tumor micro-environment (TME) by deep analyses using immunohistochemistry. We performed in vitro functional assays and highlighted a new mechanism of cooperation between cancer cells and one particular subset of cancer-associated fibroblasts (CAF).

Results

We found that specific TME features are indicative of relapse in early luminal BC. Indeed, quantitative histological analyses reveal that “cases” are characterized by significant accumulation of a particular CAF subset (CAF-S1) and decrease in CD4⁺ T lymphocytes, without any other association with immune cells. In multivariate analysis, TME features, in particular CAF-S1 enrichment, remain significantly associated with recurrence, thereby demonstrating their clinical relevance. Finally, by performing functional analyses, we demonstrated that CAF-S1 pro-metastatic activity is mediated by the CDH11/osteoblast cadherin, consistent with bones being a major site of metastases in luminal BC patients.

Conclusions

This study shows that distant recurrence in T1N0 BC is strongly associated with the presence of CAF-S1 fibroblasts. Moreover, we identify CDH11 as a key player in CAF-S1-mediated pro-metastatic activity. This is independent of tumor cells and represents a new prognostic factor. These results could assist clinicians in identifying luminal BC patients with high risk of relapse. Targeted therapies against CAF-S1 using anti-FAP antibody or CDH11-targeting compounds might help in preventing relapse for such patients with activated stroma.

A dual role of Irf1 in maintaining epithelial identity but also enabling EMT and metastasis formation of breast cancer cells

An epithelial to mesenchymal transition (EMT) is an embryonic dedifferentiation program which is aberrantly activated in cancer cells to acquire cellular plasticity. This plasticity increases the ability of breast cancer cells to invade into surrounding tissue, to seed metastasis at distant sites and to resist to chemotherapy. In this study, we have observed a higher expression of interferon-related factors in basal-like and claudin-low subtypes of breast cancer in patients, known to be associated with EMT. Notably, Irf1 exerts essential functions during the EMT process, yet it is also required for the maintenance of an epithelial differentiation status of mammary gland epithelial cells: RNAi-mediated ablation of Irf1 in mammary epithelial cells results in the expression of mesenchymal factors and Smad transcriptional activity. Conversely, ablation of Irf1 during TGFβ-induced EMT prevents a mesenchymal transition and stabilizes the expression of E-cadherin. In the basal-like murine breast cancer cell line 4T1, RNAi-mediated ablation of Irf1 reduces colony formation and cell migration in vitro and shedding of circulating tumor cells and metastasis formation in vivo. This context-dependent dual role of Irf1 in the regulation of epithelial-mesenchymal plasticity provides important new insights into the functional contribution and therapeutic potential of interferon-regulated factors in breast cancer.

C/EBPɑ is crucial determinant of epithelial maintenance by preventing epithelial-to-mesenchymal transition

Extracellular signals such as TGF-β can induce epithelial-to-mesenchymal transition (EMT) in cancers of epithelial origin, promoting molecular and phenotypical changes resulting in pro-metastatic characteristics. We identified C/EBPα as one of the most TGF-β-mediated downregulated transcription factors in human mammary epithelial cells. C/EBPα expression prevents TGF-β-driven EMT by inhibiting expression of known EMT factors. Depletion of C/EBPα is sufficient to induce mesenchymal-like morphology and molecular features, while cells that had undergone TGF-β-induced EMT reverted to an epithelial-like state upon C/EBPα re-expression. In vivo, mice injected with C/EBPα-expressing breast tumor organoids display a dramatic reduction of metastatic lesions. Collectively, our results show that C/EBPα is required for maintaining epithelial homeostasis by repressing the expression of key mesenchymal markers, thereby preventing EMT-mediated tumorigenesis. These data suggest that C/EBPα is a master epithelial "gatekeeper" whose expression is required to prevent unwarranted mesenchymal transition, supporting an important role for EMT in mediating breast cancer metastasis.

Hypoxic environment may enhance migration/penetration of endocrine resistant MCF7- derived breast cancer cells through monolayers of other non-invasive cancer cells in vitro

The response of cancer cells to hypoxic conditions found within the interior of a tumor mass is mediated through the hypoxia inducible factor (HIF) cascade and is thought to promote metastasis. However, given their distant proximity from blood vessels as compared to normoxic cells at the vascularised tumor periphery, it is uncertain if these cells can migrate through the tumor mass to gain access. Hypoxia was simulated by exposure to cobalt chloride or deferoxamine in normal (MCF10A) and cancerous [estrogen receptor (ER)−ve (pII), and ER +ve (YS1.2/ EII)] cells. In this report, HIF1α expression and localization was measured using western blotting, ELISA, and immunofluorescence, cell proliferation by MTT assay, motility and invasion by wound healing, live cell imaging, matrigel and co-culture in chambered slides. We found that the expression and nuclear translocation of HIF1α was significantly elevated by hypoxia, which inhibited cell proliferation, but significantly increased motility of pII cells and their penetration into and through a dense layer of adjacent EII cells, as well as their selective emergence out of a co-culture. These data suggest that endocrine resistant pII cancer cells, having undergone epithelial to mesenchymal transition are able to penetrate through other cell layers, with possible enhancement in response to hypoxia.