Transcriptional silencing of ETS-1 abrogates epithelial-mesenchymal transition resulting in reduced motility of pancreatic cancer cells

GATA6-AS1 suppresses epithelial-mesenchymal transition of pancreatic cancer under hypoxia through regulating SNAI1 mRNA stability

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a hypoxic microenvironment, a high rate of heterogeneity as well as a high likelihood of recurrence. Mounting evidence has affirmed that long non-coding RNAs (lncRNAs) participate in the carcinogenesis of PDAC cells. In this study, we revealed significantly decreased expression of GATA6-AS1 in PDAC based on the GEO dataset and our cohorts, and showed that low GATA6-AS1 expression was linked to unfavorable clinicopathologic characteristics as well as a poor prognosis. Gain- and loss-of-function studies demonstrated that GATA6-AS1 suppressed the proliferation, invasion, migration, and epithelial-mesenchymal transition (EMT) process of PDAC cells under hypoxia. In vivo data confirm the suppressive roles of GATA6-AS1/SNAI1 in tumor growth and lung metastasis of PDAC. Mechanistically, hypoxia-driven E26 transformation-specific sequence-1 (ETS1), as an upstream modulatory mechanism, was essential for the downregulation of GATA6-AS1 in PDAC cells. GATA6-AS1 inhibited the expression of fat mass and obesity-associated protein (FTO), an N6-methyladenosine (m6A) eraser, and repressed SNAI1 mRNA stability in an m6A-dependent manner. Our data suggested that GATA6-AS1 can inhibit PDAC cell proliferation, invasion, migration, EMT process and metastasis under hypoxia, and disrupting the GATA6-AS1/FTO/SNAI1 axis might be a viable therapeutic approach for refractory hypoxic pancreatic cancers.

Peristalsis-Associated Mechanotransduction Drives Malignant Progression of Colorectal Cancer

Introduction

In the colorectal cancer (CRC) tumor microenvironment, cancerous and precancerous cells continuously experience mechanical forces associated with peristalsis. Given that mechanical forces like shear stress and strain can positively impact cancer progression, we explored the hypothesis that peristalsis may also contribute to malignant progression in CRC. We defined malignant progression as enrichment of cancer stem cells and the acquisition of invasive behaviors, both vital to CRC progression.

Methods

We leveraged our peristalsis bioreactor to expose CRC cell lines (HCT116), patient-derived xenograft (PDX1,2) lines, or non-cancerous intestinal cells (HIEC-6) to forces associated with peristalsis in vitro. Cells were maintained in static control conditions or exposed to peristalsis for 24 h prior to assessment of cancer stem cell (CSC) emergence or the acquisition of invasive phenotypes.

Results

Exposure of HCT116 cells to peristalsis significantly increased the emergence of LGR5+ CSCs by 1.8-fold compared to static controls. Peristalsis enriched LGR5 positivity in several CRC cell lines, notably significant in KRAS mutant lines. In contrast, peristalsis failed to increase LGR5+ in non-cancerous intestinal cells, HIEC-6. LGR5+ emergence downstream of peristalsis was dependent on ROCK and Wnt activity, and not YAP1 activation. Additionally, HCT116 cells adopted invasive morphologies when exposed to peristalsis, with increased filopodia density and epithelial to mesenchymal gene expression, in a Wnt dependent manner.

Conclusions

Peristalsis associated forces drive malignant progression of CRC via ROCK, YAP1, and Wnt-related mechanotransduction.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-023-00776-w.

The role of infected epithelial cells in Chlamydia-associated fibrosis

Ocular, genital, and anogenital infection by the obligate intracellular pathogen Chlamydia trachomatis have been consistently associated with scar-forming sequelae. In cases of chronic or repeated infection of the female genital tract, infection-associated fibrosis of the fallopian tubes can result in ectopic pregnancy or infertility. In light of this urgent concern to public health, the underlying mechanism of C. trachomatis-associated scarring is a topic of ongoing study. Fibrosis is understood to be an outcome of persistent injury and/or dysregulated wound healing, in which an aberrantly activated myofibroblast population mediates hypertrophic remodeling of the basement membrane via deposition of collagens and other components of the extracellular matrix, as well as induction of epithelial cell proliferation via growth factor signaling. Initial study of infection-associated immune cell recruitment and pro-inflammatory signaling have suggested the cellular paradigm of chlamydial pathogenesis, wherein inflammation-associated tissue damage and fibrosis are the indirect result of an immune response to the pathogen initiated by host epithelial cells. However, recent work has revealed more direct routes by which C. trachomatis may induce scarring, such as infection-associated induction of growth factor signaling and pro-fibrotic remodeling of the extracellular matrix. Additionally, C. trachomatis infection has been shown to induce an epithelial-to-mesenchymal transition in host epithelial cells, prompting transdifferentiation into a myofibroblast-like phenotype. In this review, we summarize the field's current understanding of Chlamydia-associated fibrosis, reviewing key new findings and identifying opportunities for further research.

An Overview of Epithelial-to-Mesenchymal Transition and Mesenchymal-to-Epithelial Transition in Canine Tumors: How Far Have We Come?

Historically, pre-clinical and clinical studies in human medicine have provided new insights, pushing forward the contemporary knowledge. The new results represented a motivation for investigators in specific fields of veterinary medicine, who addressed the same research topics from different perspectives in studies based on experimental and spontaneous animal disease models. The study of different pheno-genotypic contexts contributes to the confirmation of translational models of pathologic mechanisms. This review provides an overview of EMT and MET processes in both human and canine species. While human medicine rapidly advances, having a large amount of information available, veterinary medicine is not at the same level. This situation should provide motivation for the veterinary medicine research field, to apply the knowledge on humans to research in pets. By merging the knowledge of these two disciplines, better and faster results can be achieved, thus improving human and canine health.

C/EBPδ Suppresses Motility-Associated Gene Signatures and Reduces PDAC Cell Migration

Pancreatic Ductal Adenocarcinoma (PDAC) is among the most aggressive human cancers and occurs globally at an increasing incidence. Metastases are the primary cause of cancer-related death and, in the majority of cases, PDAC is accompanied by metastatic disease at the time of diagnosis, making it a particularly lethal cancer. Regrettably, to date, no curative treatment has been developed for patients with metastatic disease, resulting in a 5-year survival rate of only 11%. We previously found that the protein expression of the transcription factor CCAAT/Enhancer-Binding Protein Delta (C/EBPδ) negatively correlates with lymph node involvement in PDAC patients. To better comprehend the etiology of metastatic PDAC, we explored the role of C/EBPδ at different steps of the metastatic cascade, using established in vitro models. We found that C/EBPδ has a major impact on cell motility, an important prerequisite for tumor cells to leave the primary tumor and to reach distant sites. Our data suggest that C/EBPδ induces downstream pathways that modulate actin cytoskeleton dynamics to reduce cell migration and to induce a more epithelial-like cellular phenotype. Understanding the mechanisms dictating epithelial and mesenchymal features holds great promise for improving the treatment of PDAC.

Silencing of SBF2-AS1 inhibits cell growth and invasion by sponging microRNA-338-3p in serous ovarian carcinoma

Long noncoding RNA SET-binding factor 2 (SBF2) antisense RNA 1 (AS1) is associated with the growth and metastasis of multiple cancer types, but its biological roles in serous ovarian carcinoma (SOC) remain unclear. In this study, the aberrant upregulation of SBF2-AS1 is detected in SOC after analysis of differentially expressed genes between SOC tissues and normal fallopian tubes from the public Gene Expression Omnibus (GEO) database. We determine that knockdown of SBF2-AS1 inhibits SOC cell proliferation and invasion by sponging miR-338-3p. MiR-338-3p acts as a tumor suppressor in SOC, and E26 transformation specific-1 (ETS1) is identified as a potential target of miR-338-3p regulation. Furthermore, SBF2-AS1 could modulate ETS1 by operating as a competing endogenous RNA for miR-338-3p. This finding elucidates a new mechanism for SBF2-AS1 in SOC development and provides a potential target for SOC therapeutic intervention.

Particulate matters increase epithelial-mesenchymal transition and lung fibrosis through the ETS-1/NF-κB-dependent pathway in lung epithelial cells

Background

Particulate matters (PMs) in ambient air pollution are closely related to the incidence of respiratory diseases and decreased lung function. Our previous report demonstrated that PMs-induced oxidative stress increased the expression of proinflammatory intracellular adhesion molecule-1 (ICAM-1) through the IL-6/AKT/STAT3/NF-κB pathway in A549 cells. However, the role of O-PMs in epithelial-mesenchymal transition (EMT) development and pulmonary fibrosis and the related mechanisms have not been determined. The aim of this study was to investigate the effects of O-PMs on the pathogenesis of EMT and pulmonary fibrosis as well as the expression of ETS-1 and NF-κB p65, in vitro and in vivo.

Results

O-PMs treatment induced EMT development, fibronectin expression, and cell migration. O-PMs affected the expression of the EMT-related transcription factors NF-κB p65 and ETS-1. Interference with NF-κB p65 significantly decreased O-PMs-induced fibronectin expression. In addition, O-PMs affected the expression of fibronectin, E-cadherin, and vimentin through modulating ETS-1 expression. ATN-161, an antagonist of integrin α5β1, decreased the expression of fibronectin and ETS-1 and EMT development. EMT development and the expression of fibronectin and ETS-1 were increased in the lung tissue of mice after exposure to PMs for 7 and 14 days. There was a significant correlation between fibronectin and ETS-1 expression in human pulmonary fibrosis tissue.

Conclusion

O-PMs can induce EMT and fibronectin expression through the activation of transcription factors ETS-1 and NF-κB in A549 cells. PMs can induce EMT development and the expression of fibronectin and ETS-1 in mouse lung tissues. These findings suggest that the ETS-1 pathway could be a novel and alternative mechanism for EMT development and pulmonary fibrosis.

Complete chloroplast genomes of E. umbellata Thunb., E. multiflora Thunb., E. macrophylla Thunb., and E. glabra Thunb. (Elaeagnaceae)

Elaeagnus is a genus which consists about 70 species of flowering plants in the family Elaeagnaceae, and its edible fruit is a natural product used as food and in traditional medicine. In this study, we sequenced the complete chloroplast (cp) genome of four species, namely Elaeagnus umbellate Thunb., E. multiflora Thunb., E. macrophylla Thunb., and E. glabra Thunb., to study their phylogenetic relationships within the Elaeagnaceae. Total lengths of the chloroplast genome were 152,261 bp, 152,267 bp, 152,224 bp, and 152,227 bp, respectively. The four genomes had representative quadripartite structures, with an LSC region (82,207 bp, 82,191 bp, 82,136 bp, and 82,139 bp) and an SSC region (18,262 bp, 18,282 bp,and 18,278 bp for both species) separated by a pair of IRs (25,896 bp, 25,897 bp, and 25,905 bp for the latter two species), respectively. Moreover, they were composed of 136–137 genes, including 88 protein-coding genes, 40–41 tRNA genes, and 8 rRNA genes. A maximum likelihood phylogenetic analysis indicated that E. umbellata was most closely related to E. multiflora, whereas E. macrophylla was close to E. glabra.

The Role of CCL21/CCR7 Chemokine Axis in Breast Cancer Progression

Breast cancer is a leading cause of cancer-related deaths worldwide, predominantly caused by metastasis. It is generally accepted that the pattern of breast cancer metastasis is largely determined by the interaction between the chemokine receptors on cancer cells and the chemokines expressed at the sites of metastatic disease. Chemokine receptors belong to the G-protein-coupled receptors (GPCRs) family that appear to be implicated in inflammatory diseases, tumor growth and metastasis. One of its members, C-C Chemokine receptor 7 (CCR7), binds chemokines CCL19 and CCL21, which are important for tissue homeostasis, immune surveillance and tumorigenesis. These receptors have been shown to induce the pathobiology of breast cancer due to their ability to induce cellular proliferation and migration upon the binding of the cognate chemokine receptors. The underlying signaling pathways and exact cellular interactions within this biological system are not fully understood and need further insights. Thus, in this review, we summarize the essential roles of CCR7 and its receptors in breast cancer progression. Furthermore, we discuss the mechanisms of regulation that may lead to novel opportunities for therapeutic intervention. Despite the enormous advances in our knowledge of the nature of the chemokines in breast cancer metastasis, research about the involvement of CCR7 in cancer progression is still limited. Therefore, further studies are essential to illustrate the distinct roles of CCR7 in cancer progression and validate its potential as a preventive bio-factor for human breast cancer metastasis by targeting chemokine receptor genes.

Ets-1 enhances tumor migration through regulation of CCR7 expression

Ets-1 is a prototype of the ETS protein family. Members of the ETS protein family contain a unique ETS domain. Ets-1 is associated with cancer progression and metastasis in many types of cancer. Many studies have shown a link between elevated expression of Ets-1 in cancer biopsies and poor survival. CCR7 is a chemokine that binds to specific ligand CCL21/CCL19. CCR7 expression is associated with tumor metastasis and infiltration into lymph nodes. The objective of this study was to test whether Ets-1 could regulate CCR7 expression and enhance tumor metastasis. Our data showed that CCR7 expression was downregulated in Ets-1-deficient T cells upon T-cell stimulation. Overexpression of Ets-1 increased CCR7 expression in breast cancer cell lines. In contrast, knockdown of Ets-1 reduced CCR7 expression. Ets-1 could directly bind to CCR7 promoter and mediate CCR7 expression in luciferase reporter assays and chromatin immunoprecipitation assays. Transactivation activity of Ets-1 was independent of the Pointed domain of Ets-1. Ets-1 could also enhance NF-κB and CBP transactivation of CCR7 promoter. Our results also showed that Ets-1 could modulate cancer cell transmigration by altering CCR7 expression in transwell assay and wound healing assay. Taken together, our data suggest that Ets-1 can enhance CCR7 expression and contribute to tumor cell migration.

MicroRNA-769-5p Inhibits Pancreatic Ductal Adenocarcinoma Progression by Directly Targeting and Downregulating ETS Proto-Oncogene 1

Purpose

MicroRNA-769-5p (miR-769) is aberrantly expressed and plays crucial roles in non-small cell lung cancer and melanoma. However, the expression pattern, biological role, and mechanisms of action of miR-769 in pancreatic ductal adenocarcinoma (PDAC) are yet to be fully elucidated. Therefore, we attempted to determine the potential regulatory function of miR-769 in PDAC progression and to explore the underlying mechanisms in detail.

Methods

In this study, reverse-transcription quantitative polymerase chain reaction was carried out to determine the expression profile of miR-769 in PDAC. A series of experiments, including a Cell Counting Kit-8 assay, flow-cytometric analysis, Transwell migration and invasion assays, and a xenograft animal model, were applied to test whether miR-769 affects the malignancy of PDAC.

Results

We found that miR-769 was significantly underexpressed in PDAC tissues and cell lines. The low miR-769 expression significantly correlated with the TNM stage and lymph node metastasis. Patients with PDAC harboring low miR-769 expression showed shorter overall survival than did the patients with high miR-769 expression. Forced upregulation of miR-769 suppressed PDAC cell proliferation, migration, and invasion in vitro; promoted apoptosis in vitro; and hindered tumor growth in vivo. Experiments on the mechanism identified ETS proto-oncogene 1 (ETS1) as a direct target gene of miR-769 in PDAC cells. Furthermore, ETS1 turned out to be upregulated in PDAC tissue samples, and the upregulation of ETS1 negatively correlated with miR-769 expression. Moreover, ETS1 knockdown simulated the tumor-suppressive effects of miR-769 overexpression on PDAC cells. Besides, ETS1 reintroduction attenuated the antitumor actions of miR-769 upregulation in PDAC cells.

Conclusion

Our findings indicate that miR-769 performs tumor-suppressive functions in PDAC by directly targeting ETS1, and this miRNA may represent a potential therapeutic target for the development of anticancer therapies.

Targeting Epithelial Mesenchymal Plasticity in Pancreatic Cancer: A Compendium of Preclinical Discovery in a Heterogeneous Disease

Pancreatic Ductal Adenocarcinoma (PDAC) is a particularly insidious and aggressive disease that causes significant mortality worldwide. The direct correlation between PDAC incidence, disease progression, and mortality highlights the critical need to understand the mechanisms by which PDAC cells rapidly progress to drive metastatic disease in order to identify actionable vulnerabilities. One such proposed vulnerability is epithelial mesenchymal plasticity (EMP), a process whereby neoplastic epithelial cells delaminate from their neighbours, either collectively or individually, allowing for their subsequent invasion into host tissue. This disruption of tissue homeostasis, particularly in PDAC, further promotes cellular transformation by inducing inflammatory interactions with the stromal compartment, which in turn contributes to intratumoural heterogeneity. This review describes the role of EMP in PDAC, and the preclinical target discovery that has been conducted to identify the molecular regulators and effectors of this EMP program. While inhibition of individual targets may provide therapeutic insights, a single 'master-key' remains elusive, making their collective interactions of greater importance in controlling the behaviours' of heterogeneous tumour cell populations. Much work has been undertaken to understand key transcriptional programs that drive EMP in certain contexts, however, a collaborative appreciation for the subtle, context-dependent programs governing EMP regulation is needed in order to design therapeutic strategies to curb PDAC mortality.

MicroRNA‑766 inhibits the malignant biological behaviours of pancreatic ductal adenocarcinoma by directly targeting ETS1

Increasing evidence indicates that numerous microRNAs (miRNAs) are altered in pancreatic ductal adenocarcinoma (PDAC), and their alterations significantly influence the malignant behaviour of PDAC. Therefore, identifying miRNAs associated with PDAC and their biological roles in the disease may provide promising therapeutic opportunities. Alteration of the expression of miRNA‑766 (miR‑766) has been previously reported in several types of human malignancy. However, to the best of our knowledge, whether miR‑766 exhibits different expression patterns in PDAC and its underlying functions in the progression of PDAC remain to be elucidated. In the present study, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to detect miR‑766 expression levels in PDAC tissues and cell lines. The effects of miR‑766 upregulation on PDAC cell proliferation and invasion were evaluated using MTT and invasion assays, respectively. The mechanisms underlying the role of miR‑766 in PDAC cells were explored using bioinformatics analysis, luciferase reporter assay, RT‑qPCR and western blot analysis. It was found that miR‑766 was significantly downregulated in PDAC tissues and cell lines. The detailed roles of miR‑766 in the progression of PDAC were characterised using Panc‑1 and Aspc‑1 cell lines. The results revealed that the upregulation of miR‑766 restricted the proliferation and invasion of PDAC cells. Through a series of experiments, it was found that E26 transformation specific‑1 (ETS1) was a direct target of miR‑766 in PDAC cells. Furthermore, ETS1 knockdown simulated the inhibitory effects of the overexpression of miR‑766 on PDAC cells, whereas the effects of miR‑766 restoration on the PDAC cells were reversed by overexpressing ETS1. In conclusion, the findings of the present study demonstrate that miR‑766 offers potential as a therapeutic target for patients with PDAC.

Developmental effects of the protein kinase inhibitor kenpaullone on the sea urchin embryo

The selection and validation of bioactive compounds require multiple approaches, including in-depth analyses of their biological activity in a whole-animal context. We exploited the sea urchin embryo in a rapid, medium-scale range screening to test the effects of the small synthetic kinase inhibitor kenpaullone. We show that sea urchin embryos specifically respond to this molecule depending on both dose and timing of administration. Phenotypic effects of kenpaullone are not immediately visible, since this molecule affects neither the fertilization nor the spatial arrangement of blastomeres at early developmental stages. Nevertheless, kenpaullone exposure from the beginning of embryogenesis profoundly perturbs specification, detachment from the epithelium, and migration of the primary mesenchyme cells, thus affecting the whole embryonic epithelial mesenchymal transition process. Our results reaffirm the sea urchin embryo as an excellent and sensitive in vivo system, which provides straightforward and rapid response to external stimuli.

miR-144-3p, a tumor suppressive microRNA targeting ETS-1 in laryngeal squamous cell carcinoma

Regional lymph node metastasis and distant metastasis are critical in the prognosis of laryngeal squamous cell carcinoma (LSCC). This study investigated the roles of miR-144-3p and E26 transformation specific-1 (ETS-1) in the invasion and migration of LSCC cells. The effects of miR-144-3p and ETS-1 on FaDu and Hep2 cell growth, migration and invasion were determined. Suppression of ETS-1 by miR-144-3p was confirmed using luciferase assays; the effects of ETS-1 silencing were determined using a xenograft tumor model. The expression of ETS-1 was analyzed in 71 paraffin-embedded tissue biopsies and eight fresh frozen biopsies obtained from LSCC patients. miR-144-3p inhibited the growth, invasion and migration of FaDu and Hep2 cells in part through suppression of epithelial-mesenchymal transition as determined by increased E-cadherin and α-catenin and reduced fibronectin and vimentin expression. Additionally, ETS-1 is a molecular target of miR-144-3p, and silencing ETS-1 expression inhibited FaDu and Hep2 cell invasion and migration as well as reduced Hep2 xenograft tumor volume. In LSCC, the expression of ETS-1 is upregulated with disease progression, and higher ETS-1 expression, which was negatively associated with miR-144-3p levels, adversely corresponded with prognoses. Thus, upregulated ETS-1 levels may promote LSCC metastasis, resulting in poor patient prognosis.

Identification of potential prognostic ceRNA module biomarkers in patients with pancreatic adenocarcinoma

Accumulating evidence suggested that long non-coding RNAs (lncRNAs) can function as competing endogenous RNAs (ceRNAs) to interact with other RNA transcripts and ceRNAs perturbation play important roles in cancer initiation and progression including pancreatic adenocarcinoma (PAAD). In this study, we constructed a PAAD-specific hallmark gene-related ceRNA network (HceNet) using paired genome-wide expression profiles of mRNA, lncRNA and miRNA and regulatory relationships between them. Based on “ceRNA hypothesis”, we analyzed the characteristics of HceNet and identified a ceRNA module comprising of 29 genes (12 lncRNAs, two miRNAs and 15 mRNAs) as potential prognostic biomarkers related to overall survival of patients with PAAD. The prognostic value of ceRNA module biomarkers was further validated in the train (Hazard Ratio (HR) =1.661, 95% CI: 1.275–2.165, p<1.00e-4), test (HR=1.546, 95% CI: 1.238-1.930, p<1.00e-4), and entire (HR=1.559, 95% CI: 1.321-1.839, p<1.00e-4) datasets. Our study provides candidate prognostic biomarkers for PAAD and increases our understanding of ceRNA-related regulatory mechanism in PAAD pathogenesis.

Phosphorylation of ETS-1 is a critical event in DNA polymerase iota-induced invasion and metastasis of esophageal squamous cell carcinoma

An aberrantly elevated expression of DNA polymerase ι (Pol ι) is significantly associated with poor prognosis of patients with esophageal squamous cell carcinoma (ESCC), yet the mechanisms behind this phenomenon remain obscure. Based on the RNA-Seq transcriptome and real-time PCR analysis, we identified ETS-1 as a candidate gene involved in Pol ι-mediated progression of ESCC. Wound-healing and transwell assay indicated that downregulation of ETS-1 attenuates Pol ι-mediated invasiveness of ESCC. Signaling pathway analysis showed that Pol ι enhances ETS-1 phosphorylation at threonine-38 through the Erk signaling pathway in ESCC cells. Kaplan-Meier analysis, based on 93 clinical tissue samples, revealed that ETS-1 phosphorylation at threonine-38 is associated with poor prognosis of ESCC patients. The present study thus demonstrates that phosphorylation of ETS-1 is a critical event in the Pol ι-induced invasion and metastasis of ESCC.

MicroRNA-148a suppresses epithelial-mesenchymal transition and invasion of pancreatic cancer cells by targeting Wnt10b and inhibiting the Wnt/β-catenin signaling pathway

Epithelial-mesenchymal transition (EMT) plays a critical role in the process of cancer invasion and metastasis. The Wnt/β-catenin signaling pathway is known as a stimulative factor, which may trigger EMT and metastasis of cancer cells. In addition, several microRNAs (miRNAs) have been proven to regulate the EMT process. Recent research revealed that miR‑148a is downregulated in pancreatic cancer. However, the definite role of miR-148a in EMT and invasion of pancreatic cancer is still unknown. The present study attempted to demonstrate the underlying mechanism of miR-148a in the regulation of EMT and invasion of pancreatic cancer cells. Our data revealed that the expression of miR-148a was markedly downregulated in human pancreatic ductal adenocarcinoma (PDAC) cell lines and tissues. In addition, the downregulation of miR-148a was associated with poor prognosis and EMT phenotype. Furthermore, restoration of miR-148a expression inhibited the EMT process, as well as the migration and invasion of BxPC-3 pancreatic cancer cells. Wnt10b, a promoting molecule of the Wnt/β-catenin signaling pathway, was demonstrated by dual‑luciferase reporter assay to be a direct target of miR‑148a. Subsequently, we found that miR‑148a negatively regulated the protein expression of β-catenin, cyclin D1 and MMP-9, which were important components of the Wnt/β-catenin signaling pathway. In conclusion, these findings revealed that miR-148a suppresses EMT and invasion of pancreatic cancer cells by targeting Wnt10b and inhibiting the Wnt/β-catenin signaling pathway, and thus, miR-148a may serve as a novel therapeutic target for pancreatic cancer.

Genomic Variations in Pancreatic Cancer and Potential Opportunities for Development of New Approaches for Diagnosis and Treatment

Human pancreatic cancer has a very poor prognosis with an overall five-year survival rate of less than 5% and an average median survival time of six months. This is largely due to metastatic disease, which is already present in the majority of patients when diagnosed. Although our understanding of the molecular events underlying multi-step carcinogenesis in pancreatic cancer has steadily increased, translation into more effective therapeutic approaches has been inefficient in recent decades. Therefore, it is imperative that novel and targeted approaches are designed to facilitate the early detection and treatment of pancreatic cancer. Presently, there are numerous ongoing studies investigating the types of genomic variations in pancreatic cancer and their impact on tumor initiation and growth, as well as prognosis. This has led to the development of therapeutics to target these genetic variations for clinical benefit. Thus far, there have been minimal clinical successes directly targeting these genomic alterations; however research is ongoing to ultimately discover an innovative approach to tackle this devastating disease. This review will discuss the genomic variations in pancreatic cancer, and the resulting potential diagnostic and therapeutic implications.

MicroRNA-181b-5p, ETS1, and the c-Met pathway exacerbate the prognosis of pancreatic ductal adenocarcinoma after radiation therapy

Preoperative chemoradiation therapy (CRT) for pancreatic ductal adenocarcinoma (PDAC) has emerged as a reasonable strategy that shows good prognostic impact. However, after preoperative CRT, resected specimens show remnant tumor cells, which indicate that some tumor cells had acquired or were selected for resistance to CRT. Recently, two oncological mechanisms, the EMT and the presence of CSCs, were reported to be associated with resistance in various cancers. Previous reports showed that HGF could induce EMT in PDAC cells; moreover, the HGF receptor, c‐Met, was identified as a dominant pancreatic CSC marker. However, the clinical significance of c‐Met expression remains unclear. So, we hypothesized that remnant PDAC tissue after CRT might harbor cells with high c‐Met expression, and these cells may exacerbate patients’ prognosis. In the immunohistochemical analysis, we showed that preoperative CRT was significantly associated with high c‐Met expression; moreover, high c‐Met expression was a significant marker of a dismal prognosis. Next, we investigated mechanisms of c‐Met upregulation in PDAC cells. We established GEM‐resistant and radioresistant PDAC cells to analyze the transcriptome involved in c‐Met expression. The microarray data for the established radiation‐resistant PDAC cells indicated miR‐181b‐5p downregulation, which targets ETS1, one of the transcription factors for c‐Met, and it was shown that radiation exposure induced c‐Met expression through ETS1 increase by the suppression of miR‐181b‐5p. These results suggested that targeting these mechanisms may promote the development of a novel multidisciplinary treatment strategy for improving preoperative CRT efficiency.

ETS-1: A potential target of glycolysis for metabolic therapy by regulating glucose metabolism in pancreatic cancer

Pancreatic cancer is one of the most lethal malignancies of all types of cancer due to lack of early symptoms and its resistance to conventional therapy. In our previous study, we have shown that v‑ets erythroblastosis virus E26 oncogene homolog‑1 (ETS‑1) promote cell migration and invasion in pancreatic cancer cells. However, the function of ETS‑1 in regulation of glycolysis and autophagy during progression of pancreatic cancer has not been defined yet. In this study, we sought to identify the potential role for silencing ETS‑1 in reducing the expression of glucose transporter‑1 (GLUT‑1) to disturb glycolysis through alteration of 'Warburg effect', by which could result in AMP‑activated protein kinase (AMPK) activation, autophagy induction and reduction of cell viability. MTT assay was applied to assess the cell viability in ETS‑1 silencing cells and control groups. Glucose absorption rate, lactate production rate and cellular ATP level were measured by standard colorimetric assay kits. The levels of mRNAs of ETS‑1, GLUT‑1, autophagy‑related gene 5 (ATG5) and ATG7 were analyzed by qRT‑PCR. The expression of ETS‑1, GLUT‑1, ATG5, ATG7, p‑AMPK, and LC3II proteins were evaluated by western blot analysis. GraphPad Prism 5.0 was used for all statistical analysis. We found that cell viability was obviously attenuated after silencing ETS‑1. Besides, our results also showed that the expression of GLUT‑1 significantly declined in ETS‑1 silencing cell lines which resulted in a lower glucose utilization and lactate production. Furthermore, the inhibition of glycolysis, which depends on glucose utilization and lactate production, reduced the generation of energy in the form of ATP. Moreover, the reduction of cellular ATP was associated with stimulation of AMP‑activated protein kinase (AMPK) and induction of autophagy. Our results indicated that ETS‑1 induced autophagy after inhibition of glycolysis, and thus led to comparative decrease of cell viability. These results implied that ETS‑1 could be a potential target for tumor metabolic therapy.

Blockage of SSRP1/Ets-1/Pim-3 signalling enhances chemosensitivity of nasopharyngeal carcinoma to docetaxel in vitro

Nasopharyngeal carcinoma (NPC) is a rare cancer in most parts of the world, but is prevalent in South China area. Besides, therapeutic outcome is still unsatisfactory for patients with refractory and relapsed NPC, even though receiving a second line of docetaxel-based chemotherapy. These reasons require a better understanding of mechanisms underlying the carcinogenesis, malignancy and chemoresistance. In the basis of our previous finding of SSRP1 over-expression in NPC cell lines, this study continuously discovered up-regulated Ets-1, phosphor-Ets-1 and Pim-3 in NPC tissues with immunohistochemistry assay and revealed a close correlation of these up-regulated proteins with NPC proliferation and invasion. Using gene-silencing technology followed by western blot and immunocytochemistry detections, SSRP1 was found to facilitate the translocation of phosphor-Ets-1 from cytoplasm to cell nucleus, but have marginal effect on Ets-1 expression and phosphorylation. Pim-3 was positively regulated by Ets-1. In NPC HNE-1 cells, all SSRP1, Ets-1 and Pim-3 knockdown diminished the cell proliferation, enhanced the apoptosis, as well as inhibited the autophagy, invasion and clonogenicity in the presence or absence of docetaxel at IC25. Exposure of HNE-1 cells to docetaxel (IC25) alone had modest effect on cell proliferation and autophagy, and was not as effective as docetaxel treatment after knockdown of SSRP1, Ets-1 or Pim-3 on induction of the apoptosis and on inhibition of the invasion and clonogenicity. Our data indicate that SSRP1/Ets-1/Pim-3 signalling is tightly associated with the proliferation, apoptosis, autophagy, invasion and clonogenicity of NPC cells, and blockage of this signalling facilitates chemosensitivity of the cells to docetaxel.

miR-199a-5p regulates β1 integrin through Ets-1 to suppress invasion in breast cancer

Increasing evidence has revealed that miR‐199a‐5p is actively involved in tumor invasion and metastasis as well as in the decline of breast cancer tissues. In this research, overexpression of miR‐199a‐5p weakened motility and invasion of breast cancer cells MCF‐7 and MDA‐MB‐231. Upregulation of Ets‐1 increased breast cancer cell invasion, but the mechanism by which miR‐199a‐5p modulates activation of Ets‐1 in breast cancer was not clarified. We investigated the relationship between miR‐199a‐5p and Ets‐1 on the basis of 158 primary breast cancer case specimens, and the results showed that Ets‐1 expression was inversely correlated with endogenous miR‐199a‐5p. Overexpression of miR‐199a‐5p reduced the mRNA and protein levels of Ets‐1 in MCF‐7 and MDA‐MB‐231 cells, whereas anti‐miR‐199a‐5p elevated Ets‐1. siRNA‐mediated Ets‐1 knockdown phenocopied the inhibition invasion of miR‐199a‐5p in vitro. Moreover, luciferase reporter assay revealed that miR‐199a‐5p directly targeted 3′‐UTR of Ets‐1 mRNA. This research revealed that miR‐199a‐5p could descend the levels of β1 integrin by targeting 3′‐UTR of Ets‐1 to alleviate the invasion of breast cancer via FAK/Src/Akt/mTOR signaling pathway. Our results provide insight into the regulation of β1 integrin through miR‐199a‐5p‐mediated Ets‐1 silence and will help in designing new therapeutic strategies to inhibit signal pathways induced by miR‐199a‐5p in breast cancer invasion.

The role of the transcription factor Ets1 in carcinoma

Ets1 belongs to the large family of the ETS domain family of transcription factors and is involved in cancer progression. In most carcinomas, Ets1 expression is linked to poor survival. In breast cancer, Ets1 is primarily expressed in the triple-negative subtype, which is associated with unfavorable prognosis. Ets1 contributes to the acquisition of cancer cell invasiveness, to EMT (epithelial-to-mesenchymal transition), to the development of drug resistance and neo-angiogenesis. The aim of this review is to summarize the current knowledge on the functions of Ets1 in carcinoma progression and on the mechanisms that regulate Ets1 activity in cancer.