Reassessing epithelial to mesenchymal transition as a prerequisite for carcinoma invasion and metastasis

3D porous chitosan-chondroitin sulfate scaffolds promote epithelial to mesenchymal transition in prostate cancer cells

Prostate cancer (PCa) is a common cancer in men that is curable prior to metastasis, when its prognosis worsens. Chondroitin sulfate (CS) is found in the extracellular matrix of normal prostate tissue and PCa, with greater content in metastatic PCa. Biomaterial scaffolds containing CS have yet to be evaluated for tumor microenvironment applications. Three-dimensional porous chitosan-CS (C-CS) scaffolds were developed and evaluated for PCa culture. Three C-CS scaffold compositions were prepared with 4 w/v% chitosan and 0.1, 0.5, and 1.0 w/v% CS and named 4-0.1, 4-0.5, and 4-1, respectively. The C-CS scaffolds had 90-95% porosity, average pore sizes between 143 and 166 μm, and no significant difference in scaffold stiffness. PC-3 and 22Rv1 PCa cells were cultured on the C-CS scaffolds to study the effect of CS on PCa growth and epithelial to mesenchymal transition (EMT). All C-CS scaffold compositions supported PCa growth and the 4-1 scaffolds had the greatest cell numbers for both PC-3 and 22Rv1. The C-CS scaffolds promoted upregulated EMT marker expression compared to 2D cultures with the greatest EMT marker expression in 4-1 scaffolds. Increasing CS concentration promoted upregulated vimentin expression in PC-3 cultures and N-cadherin and MMP-2 expression in 22Rv1 cultures. C-CS scaffolds promoted docetaxel drug resistance in PC-3 and 22Rv1 cultures and the 4-1 scaffold cultures had the greatest drug resistance. These results indicate that C-CS scaffolds are a promising in vitro platform for PCa.

Senescence-Associated Pro-inflammatory Cytokines and Tumor Cell Plasticity

The well-recognized cell phenotypic heterogeneity in tumors is a great challenge for cancer treatment. Dynamic interconversion and movement within a spectrum of different cell phenotypes (cellular plasticity) with the acquisition of specific cell functions is a fascinating biological puzzle, that represent an additional difficulty for cancer treatment and novel therapies development. The understanding of the molecular mechanisms responsible for moving or stabilizing tumor cells within this spectrum of variable states constitutes a valuable tool to overcome these challenges. In particular, cell transitions between epithelial and mesenchymal phenotypes (EMT-MET) and de-and trans-differentiation processes are relevant, since it has been shown that they confer invasiveness, drug resistance, and metastatic ability, due to the simultaneous acquisition of stem-like cell properties. Multiple drivers participate in these cell conversions events. In particular, cellular senescence and senescence-associated soluble factors have been shown to unveil stem-like cell properties and cell plasticity. By modulating gradually the composition of their secretome and the time of exposure, senescent cells may have differential effect not only on tumor cells but also on surrounding cells. Intriguingly, tumor cells that scape from senescence acquire stem-like cell properties and aggressiveness. The reinforcement of senescence and inflammation by soluble factors and the participation of immune cells may provide a dynamic milieu having varied effects on cell transitions, reprogramming, plasticity, stemness and therefore heterogeneity. This will confer different epithelial/mesenchymal traits (hybrid phenotype) and stem-like cell properties, combinations of which, in a particular cell context, could be responsible for different cellular functions during cancer progression (survival, migration, invasion, colonization or proliferation). Additionally, cooperative behavior between cell subpopulations with different phenotypes/stemness functions could also modulate their cellular plasticity. Here, we will discuss the role of senescence and senescence-associated pro-inflammatory cytokines on the induction of cellular plasticity, their effect role in establishing particular states within this spectrum of cell phenotypes and how this is accompanied by stem-like cell properties that, as the epithelial transitions, may also have a continuum of characteristics providing tumor cells with functional adaptability specifically useful in the different stages of carcinogenesis.

The novel miR-1269b-regulated protein SVEP1 induces hepatocellular carcinoma proliferation and metastasis likely through the PI3K/Akt pathway

Decreased intercellular adhesion is a key step in the metastasis and recurrence of many cancers, including hepatocellular carcinoma (HCC). SVEP1 is an important cell adhesion molecule that plays a key role in regulating intercellular adhesion and embryonic lymphatic development. However, the expression patterns and roles of SVEP1 in HCC are still largely unknown. We identified SVEP1 expression by analyzing 220 HCC samples from our cancer center. TCGA and GEO online-databases were used for data calibration and validation. SVEP1 was differentially expressed in two groups of HCCs with different risks of recurrence and was deemed as an independent risk factor for the prognosis of HCC. The expression of SVEP1 is negatively related to the proliferation and metastasis of HCC. Downregulation of SVEP1 expression promoted in vitro HCC cell migration, chemotaxis, invasion and proliferation, as well as in vivo tumor growth, local invasion and metastasis in a mouse model. Bioinformatic analysis and RT-PCR results showed that miR-1269b expression is negatively correlated with the SVEP1 expression and the prognosis of HCC patients. Further experiments showed that miR-1269b directly targets and downregulates the expression of SVEP1, which further induces the phosphorylation of Akt at thr308. These regulatory effects ultimately mediate the proliferation and metastasis of HCC cells. SVEP1 could serve as a promising prognostic marker of HCC. MiR-1269b downregulates SVEP1 expression and promotes HCC proliferation and metastasis likely through the PI3k/Akt signaling pathway.

Protocadherin 8 (PCDH8) Inhibits Proliferation, Migration, Invasion, and Angiogenesis in Esophageal Squamous Cell Carcinoma

BACKGROUND Protocadherin 8 (PCDH8) functions as a tumor-suppressor gene in many types of cancer. This study aimed to investigate the role of PCDH8 in esophageal squamous cell carcinoma (ESCC). MATERIAL AND METHODS Cell proliferation, apoptosis, transwell assay, tube formation assays, and tumor xenograft experiment were performed to explore the role of PCDH8 in the progression of ESCC. RESULTS PCDH8 was found to be downregulated in ESCC cells. Ectopic expression of PCDH8 blocked proliferation, invasion, and migration and induced apoptosis in ESCC cells. Furthermore, vascular endothelial growth factor A (VEGFA) secretion and the AKT signaling pathway were also inhibited when PCDH8 was upregulated. PCDH8 overexpression suppressed epithelial-mesenchymal transition (EMT) and pro-angiogenic activity of ESCC cells. In a mouse model of ESCC xenograft tumors, PCDH8 overexpression remarkably restrained tumor cell growth, with the tumor inhibition rate of 75.2%. PCDH8 was the target of miR-200c and had a negative correlation with miR-200c. CONCLUSIONS PCDH8 exerts a tumor-suppressive effect against ESCC cells. However, further studies are required to elucidate the exact molecular mechanism underlying the antitumor activity of PCDH8 in ESCC.

New Insights Into the Role of Phenotypic Plasticity and EMT in Driving Cancer Progression

Tumor cells demonstrate substantial plasticity in their genotypic and phenotypic characteristics. Epithelial-mesenchymal plasticity (EMP) can be characterized into dynamic intermediate states and can be orchestrated by many factors, either intercellularly via epigenetic reprograming, or extracellularly via growth factors, inflammation and/or hypoxia generated by the tumor stromal microenvironment. EMP has the capability to alter phenotype and produce heterogeneity, and thus by changing the whole cancer landscape can attenuate oncogenic signaling networks, invoke anti-apoptotic features, defend against chemotherapeutics and reprogram angiogenic and immune recognition functions. We discuss here the role of phenotypic plasticity in tumor initiation, progression and metastasis and provide an update of the modalities utilized for the molecular characterization of the EMT states and attributes of cellular behavior, including cellular metabolism, in the context of EMP. We also summarize recent findings in dynamic EMP studies that provide new insights into the phenotypic plasticity of EMP flux in cancer and propose therapeutic strategies to impede the metastatic outgrowth of phenotypically heterogeneous tumors.

E-Cadherin in Pancreatic Ductal Adenocarcinoma: A Multifaceted Actor during EMT

Epithelial-to-mesenchymal transition (EMT) is a step-wise process observed in normal and tumor cells leading to a switch from epithelial to mesenchymal phenotype. In tumors, EMT provides cancer cells with a metastatic phenotype characterized by E-cadherin down-regulation, cytoskeleton reorganization, motile and invasive potential. E-cadherin down-regulation is known as a key event during EMT. However, E-cadherin expression can be influenced by the different experimental settings and environmental stimuli so that the paradigm of EMT based on the loss of E-cadherin determining tumor cell behavior and fate often becomes an open question. In this review, we aimed at focusing on some critical points in order to improve the knowledge of the dynamic role of epithelial cells plasticity in EMT and, specifically, address the role of E-cadherin as a marker for the EMT axis.

Detection of circulating tumor cells in patients with laryngeal cancer using ScreenCell: Comparative pre- and post-operative analysis and association with prognosis

The presence of circulating tumor cells (CTCs) in the blood of patients with metastatic breast, colorectal and prostate cancer have been widely investigated; however, few studies have examined CTCs in patients with laryngeal cancer. The present pilot study aimed to detect pre- and postoperative CTCs in the blood of patients with laryngeal cancer and evaluate the association with prognosis. Eight patients with laryngeal squamous cell carcinoma (LSCC) at stage III were included in the present study and underwent total or subtotal laryngectomy and radical bilateral neck lymph node dissection. Blood samples were collected from all patients before and after surgery at different time-points. The following processing steps were followed; preoperative blood sampling, surgery, postoperative blood sampling at 3, 6 and 12 month follow-ups, and prognostic association analysis. CTCs were retained on ScreenCell filters for cytological characterization. The presence of CTCs was associated with a less favorable prognosis, whereas a decrease of CTCs in the postoperative sampling was observed in patients who exhibited an improved therapeutic response. The results of the present pilot study revealed a possible association between the presence of CTCs and a less favorable prognosis in patients with LSCC; therefore, these preliminary findings may encourage further research into the incorporation of a liquid biopsy in the management of LSCC, as this may help identify patients with occult metastatic disease earlier and in a non-invasive manner. In addition, this approach may represent novel independent prognostic factor for use in the clinical evaluation of patients with LSCC.

EMT Factors and Metabolic Pathways in Cancer

The epithelial-mesenchymal transition (EMT) represents a biological program during which epithelial cells lose their cell identity and acquire a mesenchymal phenotype. EMT is normally observed during organismal development, wound healing and tissue fibrosis. However, this process can be hijacked by cancer cells and is often associated with resistance to apoptosis, acquisition of tissue invasiveness, cancer stem cell characteristics, and cancer treatment resistance. It is becoming evident that EMT is a complex, multifactorial spectrum, often involving episodic, transient or partial events. Multiple factors have been causally implicated in EMT including transcription factors (e.g., SNAIL, TWIST, ZEB), epigenetic modifications, microRNAs (e.g., miR-200 family) and more recently, long non-coding RNAs. However, the relevance of metabolic pathways in EMT is only recently being recognized. Importantly, alterations in key metabolic pathways affect cancer development and progression. In this review, we report the roles of key EMT factors and describe their interactions and interconnectedness. We introduce metabolic pathways that are involved in EMT, including glycolysis, the TCA cycle, lipid and amino acid metabolism, and characterize the relationship between EMT factors and cancer metabolism. Finally, we present therapeutic opportunities involving EMT, with particular focus on cancer metabolic pathways.

Development and validation of a five-gene model to predict postoperative brain metastasis in operable lung adenocarcinoma

One of the most common sites of extra-thoracic distant metastasis of nonsmall-cell lung cancer is the brain. Our study was performed to discover genes associated with postoperative brain metastasis in operable lung adenocarcinoma (LUAD). RNA seq was performed in specimens of primary LUAD from seven patients with brain metastases and 45 patients without recurrence. Immunohistochemical (IHC) assays of the differentially expressed genes were conducted in 272 surgical-resected LUAD specimens. LASSO Cox regression was used to filter genes related to brain metastasis and construct brain metastasis score (BMS). GSE31210 and GSE50081 were used as validation datasets of the model. Gene Set Enrichment Analysis was performed in patients stratified by risk of brain metastasis in the TCGA database. Through the initial screening, eight genes (CDK1, KPNA2, KIF11, ASPM, CEP55, HJURP, TYMS and TTK) were selected for IHC analyses. The BMS based on protein expression levels of five genes (TYMS, CDK1, HJURP, CEP55 and KIF11) was highly predictive of brain metastasis in our cohort (12-month AUC: 0.791, 36-month AUC: 0.766, 60-month AUC: 0.812). The validation of BMS on overall survival of GSE31210 and GSE50081 also showed excellent predictive value (GSE31210, 12-month AUC: 0.682, 36-month AUC: 0.713, 60-month AUC: 0.762; GSE50081, 12-month AUC: 0.706, 36-month AUC: 0.700, 60-month AUC: 0.724). Further analyses showed high BMS was associated with pathways of cell cycle and DNA repair. A five-gene predictive model exhibits potential clinical utility for the prediction of postoperative brain metastasis and the individual management of patients with LUAD after radical resection.

Clinical Relevance of Circulating Tumor Cells in Esophageal Cancer Detected by a Combined MACS Enrichment Method

INTRODUCTION

Current modalities to predict tumor recurrence and survival in esophageal cancer are insufficient. Even in lymph node-negative patients, a locoregional and distant relapse is common. Hence, more precise staging methods are needed. So far, only the CellSearch system was used to detect circulating tumor cells (CTC) with clinical relevance in esophageal cancer patients. Studies analyzing different CTC detection assays using advanced enrichment techniques to potentially increase the sensitivity are missing.

METHODS

In this single-center, prospective study, peripheral blood samples from 90 esophageal cancer patients were obtained preoperatively and analyzed for the presence of CTCs by Magnetic Cell Separation (MACS) enrichment (combined anti-cytokeratin and anti-epithelial cell adhesion molecules (EpCAM)), with subsequent immunocytochemical staining. Data were correlated with clinicopathological parameters and patient outcomes.

RESULTS

CTCs were detected in 25.6% (23/90) of the patients by combined cytokeratin/EpCAM enrichment (0-150 CTCs/7.5 mL). No significant correlation between histopathological parameters and CTC detection was found. Survival analysis revealed that the presence of more than two CTCs correlated with significantly shorter overall survival (OS) and progression-free survival (PFS).

CONCLUSION

With the use of cytokeratin as an additional enrichment target, the CTC detection rate in esophageal cancer patients can be elevated and displays the heterogeneity of cytokeratin (CK) and EpCAM expression. The presence of >2CTCs correlated with a shorter relapse-free and overall survival in a univariate analysis, but not in a multivariate setting. Moreover, our results suggest that the CK7/8+/EpCAM+ or CK7/8+/EpCAM- CTC subtype does not lead to an advanced tumor staging tool in non-metastatic esophageal cancer (EC) patients.

FoxM1 affects adhesive, migratory, and invasive abilities of human retinoblastoma Y-79 cells by targeting matrix metalloproteinase 2

Forkhead box protein M1 (FoxM1) is an important transcription factor involved in various pathological processes including tumor metastasis. The changes of adhesive, migratory, and invasive abilities are considered as crucial events in tumor metastasis progression. In this study, we aimed to investigate the correlation between FoxM1 and retinoblastoma (Rb) metastasis and to explore the detailed mechanism. Wound healing, cell adhesion, and invasion assays showed that FoxM1 overexpression induced epithelial-mesenchymal transition in Y-79 cells and inhibited adhesion and subsequently promoted metastasis of Y-79 cells, while FoxM1 knockdown showed the opposite effects. A luciferase reporter assay and chromatin immunoprecipitation assay provided evidence that FoxM1 promoted matrix metalloproteinase 2 (MMP2) transcription by directly binding to and promoting MMP2 promoter. MMP2 knockdown by siRNA transfection attenuated cell metastasis of Y-79 cells induced by FoxM1 overexpression. Furthermore, the FoxM1-binding site mapped between -1167 and -1161 bp of the MMP2 promoter was identified. Our results suggested that the FoxM1-MMP2 axis plays an important role in Rb metastasis, which may be a novel target for designing therapeutic regimen to control Rb metastasis.

MicroRNA-96-5p promotes proliferation, invasion and EMT of oral carcinoma cells by directly targeting FOXF2

Recently, microRNA-96-5p (miR-96-5p) has been reported to function as both a tumor suppressor and oncogene in several cancer types, including gastric cancer, hepatocellular cancer and lung cancer. However, the biological function of miR-96-5p and its precise mechanisms in oral squamous cell carcinoma (OSCC) have not been well clarified. The aim of this study was to study the roles of miR-96-5p/FOXF2 axis in OSCC. In this study, the miR-96-5p level was dramatically enhanced in OSCC tissues and cell lines, and the FOXF2 expression was significantly reduced. In addition, the FOXF2 expression was negatively related to the miR-96-5p level in OSCC tissues. Furthermore, downregulation of miR-96-5p obviously restrained OSCC cell proliferation, invasion and EMT. We confirmed that miR-96-5p could directly target FOXF2 by luciferase reporter assay. Moreover, knockdown of FOXF2 also could markedly promote the proliferation, invasion and EMT of OSCC cells. Finally, overexpression of FOXF2 in OSCC cells partially reversed the promoted effects of miR-96-5p mimic. Knockdown of miR-96-5p restrained OSCC cells proliferation, invasion and EMT via regulation of FOXF2.

An ultrastructural pathologist's views on fibroblasts, modified smooth muscle cells, wound healing, stenosing arteriopathies, Kawasaki disease, Dupuytren's contracture, and the stroma of carcinomas

It wasn't until 1960 that the dense bodies of the peripheral actin arrays of fibroblasts were finally visualized, i.e., stress fibers (SFs). Mistakenly assumed that its SFs turned the fibroblast into a unique cell situated somewhere in a continuum between it and a smooth muscle cell (SMC), it was descriptively named a "myofibroblast" (MF). Automatically, spindle cells with SFs and/or smooth muscle actin by SMA IHC-staining, became MFs, although endothelial cells, pericytes, modified SMCs (mSMC), and myoepithelial cells all contain SFs. An invisible "intermediate" cell was hypothesized to exist somewhere between SMA-negative and positive fibroblasts, and named a "proto-myofibroblast". The sub-epithelial spindle cells of normal and malignant tumors of the GI, GU, and respiratory tracts are all fibroblasts with SFs. The second erroneous myofibroblast came from a 1971 rat wound healing study and its 1974 human counterpart. Updated analysis of the papers' TEMs proved that the cells are mSMCs and not fibroblasts (AKA: MFs). The pathognomonic cells of Dupuytren's contracture are mSMCs and fibroblasts and that of the stenosing arteriopathy of Kawasaki Disease and other similar arteriopathies are mSMCs. TEM remains a powerful tool.

Silibinin inhibits epithelial‑mesenchymal transition of renal cell carcinoma through autophagy‑dependent Wnt/β‑catenin signaling

Silibinin is a flavonoid extracted from milk thistle seeds which has been widely used as a hepatoprotective and antioxidant agent. Recently, accumulating evidence has demonstrated the anti-cancer effects of silibinin in various cancer models. It was previously reported that silibinin induced apoptosis and decreased metastasis by activating autophagy in renal cell carcinoma (RCC). However, the underlying molecular mechanisms by which silibinin regulates autophagy remain largely unknown. The aim of the present study was to investigate the effects of silibinin on RCC metastasis in vitro and in vivo, with a focus on autophagy-dependent Wnt/β-catenin signaling. Human RCC 786-O and ACHN cell lines were used as the model system in vitro and RCC xenografts of nude mice were used for in vivo studies. Silibinin inhibited metastasis and epithelial-mesenchymal transition (EMT) of RCC in vitro and in vivo, by regulating the Wnt/β-catenin signaling pathway. Furthermore, silibinin inhibited the Wnt/β-catenin signaling pathway in an autophagy-dependent manner. Autophagic degradation of β-catenin induced by silibinin was associated with the anti-metastatic effects of silibinin against RCC. These findings identify a novel mechanism by which silibinin inhibits EMT and metastasis of RCC, highlighting a potential novel strategy for treating metastatic RCC.

The Role of Carcinogenesis-Related Biomarkers in the Wnt Pathway and Their Effects on Epithelial-Mesenchymal Transition (EMT) in Oral Squamous Cell Carcinoma

As oral squamous cell carcinoma (OSCC) can develop from potentially malignant disorders (PMDs), it is critical to develop methods for early detection to improve the prognosis of patients. Epithelial-mesenchymal transition (EMT) plays an important role during tumor progression and metastasis. The Wnt signaling pathway is an intercellular pathway in animals that also plays a fundamental role in cell proliferation and regeneration, and in the function of many cell or tissue types. Specific components of master regulators such as epithelial cadherin (E-cadherin), Vimentin, adenomatous polyposis coli (APC), Snail, and neural cadherin (N-cadherin), which are known to control the EMT process, have also been implicated in the Wnt cascade. Here, we review recent findings on the Wnt signaling pathway and the expression mechanism. These regulators are known to play roles in EMT and tumor progression, especially in OSCC. Characterizing the mechanisms through which both EMT and the Wnt pathway play a role in these cellular pathways could increase our understanding of the tumor genesis process and may allow for the development of improved therapeutics for OSCC.

HJC0152 suppresses human non-small-cell lung cancer by inhibiting STAT3 and modulating metabolism

Objectives

Signal transducer and activator of transcription 3 (STAT3) is constitutively activated and overexpressed in many cancers, including non–small‐cell lung cancer (NSCLC). We recently developed HJC0152 as an orally active STAT3 inhibitor. This study focused on investigating HJC0152's effect and mechanism of action in NSCLC.

Materials and methods

We analysed cell proliferation by MTT assays, cell migration by wound healing and transwell assays, protein levels by Western blot, and apoptosis and reactive oxygen species (ROS) level by flow cytometry. A nude mouse tumorigenesis model was established for in vivo experiment. UHPLC‐QTOF/MS was used for untargeted metabolomic relative quantitation analysis.

Results

We found that HJC0152 exhibited activity against human NSCLC cells in vitro and NSCLC xenograft tumours in vivo via regulating STAT3 signalling and metabolism. HJC0152 efficiently reduced NSCLC cell proliferation, promoted ROS generation, induced apoptosis, triggered DNA damage and reduced motility in A549 and H460 NSCLC cells. Moreover, HJC0152 significantly inhibited the growth of A549 xenograft tumours in vivo. HJC0152 also affected metabolism, significantly decreasing and perturbating levels of several metabolites in the purine, glutathione and pyrimidine metabolism pathways.

Conclusions

HJC0152 reduces cellular capacity to scavenge free radicals, leading to ROS generation and accumulation and apoptosis. This study provides a rationale for further developing HJC0152 as a potential therapy for NSCLC and provides insights into the mechanisms by which HJC0152 exerts its anti‐cancer effects.

CCL21/CCR7 interaction promotes EMT and enhances the stemness of OSCC via a JAK2/STAT3 signaling pathway

Chemokines and their receptors show a strong relationship with poor clinical outcomes in various cancers. However, their underlying mechanisms remain to be fully elucidated. In our research, we found C-C chemokine receptor 7 (CCR7) and its ligand chemokine ligand 21 (CCL21) were abnormally abundant in oral squamous cell carcinoma (OSCC) tissues, and CCR7 expression was correlated with poor prognosis of OSCC. After exogenous CCL21 stimulation, epithelial-mesenchymal transition (EMT) was promoted in OSCC cells, and cancer stem cell-related markers CD133, CD44, BMI1, ALDH1A1, and OCT4 increased. The migration, invasion, tumorsphere formation, and colony formation abilities of OSCC cells were enhanced, indicating that the stemness of OSCC cells was also improved. The knockdown and overexpression of CCR7 efficiently affected the CCL21-induced EMT and stemness of OSCC cells. When treated with CCL21, the phospho-JAK2 and phospho-STAT3 markedly increased. The inhibitor of the Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) significantly suppressed CCL21-induced EMT and stemness of OSCC cells. In conclusion, CCL21/CCR7 axis regulated EMT progress and promoted the stemness of OSCC by activating the JAK2/STAT3 signaling pathway. CCL21/CCR7 might be an effective target for OSCC prevention and treatment.

A microcarrier-based spheroid 3D invasion assay to monitor dynamic cell movement in extracellular matrix

Background

Cell invasion through extracellular matrix (ECM) is a critical step in tumor metastasis. To study cell invasion in vitro, the internal microenvironment can be simulated via the application of 3D models.

Results

This study presents a method for 3D invasion examination using microcarrier-based spheroids. Cell invasiveness can be evaluated by quantifying cell dispersion in matrices or tracking cell movement through time-lapse imaging. It allows measuring of cell invasion and monitoring of dynamic cell behavior in three dimensions. Here we show different invasive capacities of several cell types using this method. The content and concentration of matrices can influence cell invasion, which should be optimized before large scale experiments. We also introduce further analysis methods of this 3D invasion assay, including manual measurements and homemade semi-automatic quantification. Finally, our results indicate that the position of spheroids in a matrix has a strong impact on cell moving paths, which may be easily overlooked by researchers and may generate false invasion results.

Conclusions

In all, the microcarrier-based spheroids 3D model allows exploration of adherent cell invasion in a fast and highly reproducible way, and provides informative results on dynamic cell behavior in vitro.

LncRNA HOTAIR promotes the invasion and metastasis of oral squamous cell carcinoma through metastasis-associated gene 2

Despite therapeutic advancements, there has been little improvement in the survival status of patients with oral squamous cell carcinoma (OSCC). HOX antisense intergenic RNA (HOTAIR) has been shown to be dysregulated in several cancer types. However, the roles of HOTAIR in OSCC remain largely unknown. In this study, we investigated the association of HOTAIR expression with clinicopathological features in OSCC patients and the crucial roles of HOTAIR in the modulation of tumor progression. Our results showed that HOTAIR was highly expressed both in OSCC tissue samples and cell lines compared with corresponding normal oral mucosa tissues and human oral keratinocytes. Its overexpression was positively correlated with TNM (tumor-node-metastases) stage, histological grade, and regional lymph node metastasis. The knockdown of HOTAIR by short hairpin RNA significantly decreased the migration, invasion, and epithelial-mesenchymal transition of OSCC cells in vitro. Moreover, there was a negative correlation between HOTAIR and microRNA-326 expression in OSCC tissue samples and cell lines. Luciferase reporter and loss-of-function assays revealed that HOTAIR acted as a competitive endogenous RNA effectively sponging miR-326, thereby regulating the derepression of metastasis-associated gene 2 (MTA2). Finally, the expression and clinical significance of MTA2 were analyzed in another cohort of OSCC tissue samples. High MTA2 expression was significantly correlated with clinicopathological features of advanced OSCC and poor prognosis for patients with OSCC. Collectively, HOTAIR overexpression promoted the progression of OSCC. The HOTAIR-miR-326-MTA2 axis may contribute to a better understanding of OSCC pathogenesis and be a potential therapeutic target for OSCC.

Dact2 is involved in the regulation of epithelial-mesenchymal transition

Dishevelled-associated antagonist of beta-catenin 2 (Dact2) is involved in the regulation of intracellular signaling pathways during development. It negatively regulates the Nodal signaling pathway, possibly by promoting lysosomal degradation of Nodal receptors such as TGFBR1, and plays an inhibitory role during the re-epithelialization of skin wounds by attenuating transforming growth factor-β signaling. Dact2 is known to act as a functional tumor suppressor in colon cancer; reduced Dact2 can promote liver cancer progression and suppress gastric cancer proliferation, invasion, and metastasis by inhibiting Wnt signaling. Zebrafish is used as a model of cancer biology because it shows similar tumorigenesis and morphogenesis as in humans and gene manipulation in this organism is possible. This study was performed to explore phenotypic changes in Dact2 knockout zebrafish and investigate the function of Dact2. A 10-base pair deletion Dact2 knockout zebrafish was prepared using the CRISPR-Cas9 genome editing system. Dact2 knockout enhanced the expression of the MMP2 and MMP9 genes, which are related to tumor invasion and migration, and the Snail, VEGF, and ZEB genes, which are related to epithelial-mesenchymal transition (EMT). The absence of Dact2 also resulted in hyperplasia of the gastrointestinal epithelium, fibrosis in the pancreas and liver, increased proliferation of the pancreatic and hepatic bile ducts, and invasive proliferation into the pancreas. A wound healing assay confirmed that the absence of Dact2 enhanced EMT, thus accelerating wound healing. This study suggests that a loss of function of Dact2 impacts EMT-related gene regulation and tumor generation in a zebrafish knockout model, which is a useful model for exploring the mechanisms of these processes.

Unjamming and collective migration in MCF10A breast cancer cell lines

Each cell comprising an intact, healthy, confluent epithelial layer ordinarily remains sedentary, firmly adherent to and caged by its neighbors, and thus defines an elemental constituent of a solid-like cellular collective [1,2]. After malignant transformation, however, the cellular collective can become fluid-like and migratory, as evidenced by collective motions that arise in characteristic swirls, strands, ducts, sheets, or clusters [3,4]. To transition from a solid-like to a fluid-like phase and thereafter to migrate collectively, it has been recently argued that cells comprising the disordered but confluent epithelial collective can undergo changes of cell shape so as to overcome geometric constraints attributable to the newly discovered phenomenon of cell jamming and the associated unjamming transition (UJT) [1,2,5-9]. Relevance of the jamming concept to carcinoma cells lines of graded degrees of invasive potential has never been investigated, however. Using classical in vitro cultures of six breast cancer model systems, here we investigate structural and dynamical signatures of cell jamming, and the relationship between them [1,2,10,11]. In order of roughly increasing invasive potential as previously reported, model systems examined included MCF10A, MCF10A.Vector; MCF10A.14-3-3ζ; MCF10.ErbB2, MCF10AT; and MCF10CA1a [12-15]. Migratory speed depended on the particular cell line. Unsurprisingly, for example, the MCF10CA1a cell line exhibited much faster migratory speed relative to the others. But unexpectedly, across different cell lines higher speeds were associated with enhanced size of cooperative cell packs in a manner reminiscent of a peloton [9]. Nevertheless, within each of the cell lines evaluated, cell shape and shape variability from cell-to-cell conformed with predicted structural signatures of cell layer unjamming [1]. Moreover, both structure and migratory dynamics were compatible with previous theoretical descriptions of the cell jamming mechanism [2,10,11,16,17]. As such, these findings demonstrate the richness of the cell jamming mechanism, which is now seen to apply across these cancer cell lines but remains poorly understood.

Liquid Biopsy Based on Circulating Cancer-Associated Cells: Bridging the Gap from an Emerging Concept to a Mainstream Tool in Precision Medicine

The concept of liquid biopsy and the isolation and analysis of circulating biomarkers from blood samples is proposed as a surrogate to solid biopsies and can have the potential to revolutionize the management of patients with cancer. The relevance of circulating tumor cells (CTCs) and the importance of the information they carry is acknowledged by the medical community. But what are the barriers to clinical adoption? This review draws a panorama of the biological implications of CTCs, their physical and biochemical properties, and the current technological bottlenecks for their analysis in relation with the medical needs. Keys and considerations to bridge the technological and clinical gaps that still need to be overcome to be able to introduce CTCs in clinical routine are finally synthesized.

Diversity of collective migration patterns of invasive breast cancer cells emerging during microtrack invasion

Understanding the mechanisms underlying the diversity of tumor invasion dynamics, including single-cell migration, multicellular streaming, and the emergence of various collective migration patterns, is a long-standing problem in cancer research. Here we have designed and fabricated a series of microchips containing high-throughput microscale tracks using protein repelling coating technology, which were then covered with a thin Matrigel layer. By varying the geometrical confinement (track width) and microenvironment factors (Matrigel concentration), we have reproduced a diversity of collective migration patterns in the chips, which were also observed in vivo. We have further classified the collective patterns and quantified the emergence probability of each class of patterns as a function of microtrack width and Matrigel concentration to devise a quantitive "collective pattern diagram." To elucidate the mechanisms behind the emergence of various collective patterns, we employed cellular automaton simulations, incorporating the effects of both direct cell-cell interactions and microenvironment factors (e.g., chemical gradient and extracellular matrix degradation). Our simulations suggest that tumor cell phenotype heterogeneity, and the associated dynamic selection of a favorable phenotype via cell-microenivronment interactions, are key to the emergence of the observed collective patterns in vitro.

Pannexin1 Is Associated with Enhanced Epithelial-To-Mesenchymal Transition in Human Patient Breast Cancer Tissues and in Breast Cancer Cell Lines

Loss of connexin-mediated cell-cell communication is a hallmark of breast cancer progression. Pannexin1 (PANX1), a glycoprotein that shares structural and functional features with connexins and engages in cell communication with its environment, is highly expressed in breast cancer metastatic foci; however, PANX1 contribution to metastatic progression is still obscure. Here we report elevated expression of PANX1 in different breast cancer (BRCA) subtypes using RNA-seq data from The Cancer Genome Atlas (TCGA). The elevated PANX1 expression correlated with poorer outcomes in TCGA BRCA patients. In addition, gene set enrichment analysis (GSEA) revealed that epithelial-to-mesenchymal transition (EMT) pathway genes correlated positively with PANX1 expression. Pharmacological inhibition of PANX1, in MDA-MB-231 and MCF-7 breast cancer cells, or genetic ablation of PANX1, in MDA-MB-231 cells, reverted the EMT phenotype, as evidenced by decreased expression of EMT markers. In addition, PANX1 inhibition or genetic ablation decreased the invasiveness of MDA-MB-231 cells. Our results suggest PANX1 overexpression in breast cancer is associated with a shift towards an EMT phenotype, in silico and in vitro, attributing to it a tumor-promoting effect, with poorer clinical outcomes in breast cancer patients. This association offers a novel target for breast cancer therapy.

Antioxidation and Antiapoptosis Characteristics of Heme Oxygenase-1 Enhance Tumorigenesis of Human Prostate Carcinoma Cells

Heme oxygenase-1 (HO-1) has antiinflammatory and antioxidant properties and is deemed as a tissue protector. However, effects of HO-1 in prostate cancer remain in controversy. We evaluated the role of HO-1 in prostate carcinoma in vitro and in vivo.

Overexpression of HO-1 did not affect prostate cell proliferation in the normal condition but enhanced cell proliferation under serum starvation. HO-1 overexpression enhanced cell invasion of PC-3 cells through epithelial–mesenchymal transition (EMT) induction, which was supported by increased Slug, N-cadherin, and vimentin expressions. In the xenograft animal study, HO-1 overexpression enhanced PC-3 cell tumor growth in vivo. HO-1 attenuated reactive oxygen species induced by H₂O₂ or pyocyanin treatment in PC-3 and DU145 cells. HO-1 further reduced PC-3 and DU145 cell apoptosis induced by H₂O₂ or serum starvation. Our results suggested that HO-1 was able to increase prostate carcinoma cell invasion in vitro and tumor growth in vivo. The EMT induction and antioxidant and antiapoptotic effects of HO-1 in the prostate carcinoma cells may be responsible for these findings.

Controversies around epithelial-mesenchymal plasticity in cancer metastasis

Experimental evidence accumulated over decades has implicated epithelial-mesenchymal plasticity (EMP), which collectively encompasses epithelial-mesenchymal transition and the reverse process of mesenchymal-epithelial transition, in tumour metastasis, cancer stem cell generation and maintenance, and therapeutic resistance. However, the dynamic nature of EMP processes, the apparent need to reverse mesenchymal changes for the development of macrometastases and the likelihood that only minor cancer cell subpopulations exhibit EMP at any one time have made such evidence difficult to accrue in the clinical setting. In this Perspectives article, we outline the existing preclinical and clinical evidence for EMP and reflect on recent controversies, including the failure of initial lineage-tracing experiments to confirm a major role for EMP in dissemination, and discuss accumulating data suggesting that epithelial features and/or a hybrid epithelial-mesenchymal phenotype are important in metastasis. We also highlight strategies to address the complexities of therapeutically targeting the EMP process that give consideration to its spatially and temporally divergent roles in metastasis, with the view that this will yield a potent and broad class of therapeutic agents.

N3ICD with the transmembrane domain can effectively inhibit EMT by correcting the position of tight/adherens junctions

EMT allows a polarized epithelium to lose epithelial integrity and acquire mesenchymal characteristics. Previously, we found that overexpression of the intracellular domain of Notch3 (N3ICD) can inhibit EMT in breast cancer cells. In this study, we aimed to elucidate the influence of N3ICD or N3ICD combined with the transmembrane domain (TD+N3ICD) on the expression and distribution of TJs/AJs and polar molecules. We found that although N3ICD can upregulate the expression levels of the above-mentioned molecules, TD+N3ICD can inhibit EMT more effectively than N3ICD alone. TD+N3ICD overexpression upregulated the expression of endogenous full-length Notch3 and contributed to correcting the position of TJs/AJs molecules and better acinar structures formation. Co-immunoprecipitation results showed that the upregulated endogenous full-length Notch3 could physically interact with E-ca in MDA-MB-231/pCMV-(TD+N3ICD) cells. Collectively, our data indicate that overexpression of TD+N3ICD can effectively inhibit EMT, resulting in better positioning of TJs/AJs molecules and cell-cell adhesion in breast cancer cells. Abbreviations: EMT: Epithelial-mesenchymal transition; TJs: Tight junctions; AJs: Adherens junctions; aPKC: Atypical protein kinase C; Crb: Crumbs; Lgl: Lethal (2) giant larvae; LLGL2: lethal giant larvae homolog 2; PAR: Partitioning defective; PATJ: Pals1-associated TJ protein.

MiR-21 Promotes the Invasion and Metastasis of Gastric Cancer Cells by Activating Epithelial-Mesenchymal Transition

BACKGROUND

Gastric cancer (GC) is one of the most common malignant tumors. It is likely to occur in lymph nodes and is prone to distant metastasis in its early stages, which portends a poor prognosis. Previous studies have shown that miRNA-21 was abnormally highly expressed and associated with early metastasis in GC, but the mechanism by which it regulates the invasion and metastasis of GC has not been elucidated.

METHODS

Epithelial-mesenchymal transition (EMT) is an important pathologic basis of tumor invasion and metastasis, and in this study, the relationship between miRNA-21 and EMT in GC invasion and metastasis was investigated using RT-qPCR, Western blot, and wound scratch and transwell assays.

RESULTS

We found that miRNA-21 expression in GC cell lines was higher than in a gastric mucosal epithelial cell line. After transfection with an miRNA-21 mimic, the upregulation of EMT was found to promote migration and invasion of MGC-803 cells. However, the downregulation of EMT was found to accompany the inhibition of invasion and migration of GC cells after downregulation of miRNA-21 expression due to the transfection of an miRNA-21 inhibitor.

CONCLUSIONS

These findings suggest that miRNA-21 might promote the invasion and metastasis of GC by upregulating EMT.

miR-802 inhibits the proliferation, invasion, and epithelial-mesenchymal transition of glioblastoma multiforme cells by directly targeting SIX4

It is well known that the sine oculis homeobox 4 (SIX4) expression is very relevant to the progression of multiple cancers. Moreover, we found that miR-802 could directly target the SIX4. However, the precise mechanism of miR-802 in glioblastoma multiforme (GBM) is still unknown. The aim of this study is to investigate the roles of miR-802/SIX4 axis in GBM. Here, our results showed that the SIX4 expression was obviously increased in GBM tissues and cell lines, and the miR-802 level was distinctly decreased. What is more, the SIX4 expression was negatively related to the miR-802 level in GBM tissues. Furthermore, increased miR-802 level evidently restrained the proliferation, invasion, and epithelial-mesenchymal transition (EMT) of GBM cells. Next, we confirmed that miR-802 could directly target SIX4 by using luciferase reporter assay. Besides, the knockdown of SIX4 had the similar effects with miR-802 overexpression on GBM cells. The inhibitory effects of miR-802 mimic were partially blocked by SIX4 overexpression. Altogether, the overexpression of miR-802 restrained cell proliferation, invasion, and EMT of GBM cells via the regulation of SIX4. SIGNIFICANCE OF THE STUDY: An elevated expression of SIX4 has been observed in colorectal cancer and nonsmall cell lung cancer. However, the precise roles of SIX4 in GBM have not been elucidated. Our study for the first time demonstrated that SIX4 level was significantly upregulated in GBM. Additionally, the knockdown of SIX4 inhibited cell growth, invasion, and the EMT of GBM. Moreover, our data suggested a significant negative correlation between miR-802 and SIX4 expression in GBM. MiR-802 suppressed GBM cell proliferation, invasion, and EMT by directly targeting SIX4, which suggested important roles for miR-802/SIX4 axis in the GBM pathogenesis and its potential application in cancer therapy.

High-Efficiency Isolation and Rapid Identification of Heterogeneous Circulating Tumor Cells (CTCs) Using Dual-Antibody-Modified Fluorescent-Magnetic Nanoparticles

Extreme rarity and inherent heterogeneity of circulating tumor cells (CTCs) result in a tremendous challenge for the CTC isolation from patient blood samples with high efficiency and purity. Current CTC isolation approaches mainly rely on the epithelial cell adhesion molecule (EpCAM), which may significantly reduce the ability to capture CTCs when the expression of EpCAM is lost or down-regulated in epithelial-mesenchymal transition. Here, a rapid and highly efficient method is developed to isolate and identify heterogeneous CTCs with high efficiency from patient blood samples using the fluorescent-magnetic nanoparticles (F-MNPs). A dual-antibody interface targeting EpCAM and N-cadherin is fabricated onto the F-MNPs to capture epithelial CTCs as well as mesenchymal CTCs from whole blood samples. The poly(carboxybetaine methacrylate) brushes of excellent antifouling properties are employed to decrease nonspecific cell adhesion. Moreover, the F-MNPs provide a prompt identification strategy for heterogeneous CTCs (F-MNPs+, Hoechst 33342+, and CD45-) that can directly identify CTCs in a gentle one-step processing within 1 h after isolation from patient blood samples. This has been demonstrated through artificial samples as well as patient samples in details.

Morphological quantification of proliferation-to-invasion transition in tumor spheroids

BACKGROUND

Metastasis determines the lethality of cancer. In most clinical cases, patients are able to live with tumor proliferation before metastasis. Thus, the transition from tumor proliferation to metastasis/invasion is essential. However, the mechanism is still unclear and especially, the proliferation-to-metastasis/invasion transition point has not been well defined. Therefore, quantitative characterization of this transition is urgently needed.

METHODS

We have successfully developed a home-built living-cell incubation system combined with an inverted optical microscope, and a systematic, quantitative approach to describing the major characteristic morphological parameters for the identification of the critical transition points for tumor-cell spheroids in a collagen fiber scaffold.

RESULTS

The system focuses on in vitro tumor modeling, e.g. the development of tumor-cell spheroids in a collagen fiber scaffold and the monitoring of cell transition from proliferation to invasion. By applying this approach to multiple tumor spheroid models, such as U87 (glioma tumor), H1299 (lung cancer), and MDA-MB-231 (breast cancer) cells, we have obtained quantitative morphological references to evaluate the proliferation-to-invasion transition time, as well as differentiating the invasion potential of tumor cells upon environmental changes, i.e. drug application.

CONCLUSIONS

Our quantitative approach provides a feasible clarification for the proliferation-to-invasion transition of in vitro tumor models (spheroids). Moreover, the transition time is a useful reference for the invasive potential of tumor cells.

GENERAL SIGNIFICANCE

This quantitative approach is potentially applicable to primary tumor cells, and thus has potential applications in the fields of cancer metastasis investigations and clinical diagnostics.

GATA3 suppresses human fibroblasts-induced metastasis of clear cell renal cell carcinoma via an anti-IL6/STAT3 mechanism

Tumorigenesis and metastasis depend on intricate interactions between genetically altered tumor cells and their surrounding microenvironment. It is, however, unclear regarding the molecular mechanisms underlying the progress and metastasis of human clear-cell renal cell carcinoma in the microenvironment with fibroblasts. In this work, we investigated the effect of normal fibroblasts on the metastasis of renal cancer and the relevant signaling pathways. We isolated normal fibroblasts from normal renal tissues and used normal fibroblast-conditioned medium culture renal cancer cells. The CCK-8 and transwell assays showed that normal fibroblasts conditioned medium significantly enhanced ccRCC cell migration. IL6 mediated the cross talk between normal fibroblasts and the cancer cells, and promoted tumor cell migration through the STAT3 pathway. In contrast, GATA3 was downregulated at both mRNA and protein levels in the normal fibroblast-conditioned medium treated with renal cancer cells, but upregulated in adjacent normal tissues. GATA3 overexpression significantly reduced STAT3 phosphorylation and attenuated the migration in both renal cancer cell and IL6-stimulated renal cancer cell. Taken together, our findings suggest that the IL6/STAT3 pathway plays a crucial role in the normal fibroblast-enhanced clear-cell renal cell carcinoma metastasis, while GATA3 may mitigate this effect by inhibiting IL6/STAT3 signaling.

Prognostic and pathological impact of tumor budding in gastric cancer: A systematic review and meta-analysis

BACKGROUND

Tumor budding, is a promising prognostic hallmark in many cancers, and can help us better assess the degree of malignancy in gastric cancer (GC) and in colorectal cancer. In the past few years, several articles on the relationship between tumor budding and GC have been published, but different results have been observed. As the relationship between tumor budding and GC remains controversial, we integrated the data from 7 eligible studies to conduct a systematic review and meta-analysis.

AIM

To systematically evaluate the prognostic and pathological impact of tumor budding in GC.

METHODS

Literature searches were conducted in the PubMed, Cochrane Library, EMBASE and Web of Science databases, and 7 cohort studies involving 2178 patients met our criteria and included in the analysis. The patients were divided into those with high-grade tumor budding and those with low-grade tumor budding, and the cut-off values for tumor budding varied across the included studies. The hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to estimate the impact of tumor budding on overall survival (OS) in GC patients. The odds ratios (ORs) with 95%CIs were used to determine the correlation between tumor budding and pathological parameters (tumor stage, tumor differentiation, lymphovascular invasion, lymph node metastasis) of GC.

RESULTS

Seven studies involving 2178 patients were included in the meta-analysis. The combined ORs suggested that high-grade tumor budding was significantly associated with tumor stage (OR = 6.63, 95%CI: 4.01-10.98, P < 0.01), tumor differentiation (OR = 3.74, 95%CI: 2.68-5.22, P < 0.01), lymphovascular invasion (OR = 7.85, 95%CI: 5.04-12.21, P < 0.01), and lymph node metastasis (OR = 5.75, 95%CI: 3.20-10.32, P < 0.01). Moreover, high-grade tumor budding predicted a poor 5-year OS (HR = 1.79, 95%CI: 1.53-2.05, P < 0.01) in patients with GC and an adverse 5-year OS (HR = 1.93, 95%CI: 1.45-2.42, P < 0.01) in patients with intestinal-type GC.

CONCLUSION

High-grade tumor budding suggested a poor prognosis in patients with GC or intestinal-type GC.

Small molecule FAK activator promotes human intestinal epithelial monolayer wound closure and mouse ulcer healing

GI mucosal healing requires epithelial sheet migration. The non-receptor tyrosine kinase focal adhesion kinase (FAK) stimulates epithelial motility. A virtual screen identified the small drug-like FAK mimic ZINC40099027, which activates FAK. We assessed whether ZINC40099027 promotes FAK-Tyr-397 phosphorylation and wound healing in Caco-2 monolayers and two mouse intestinal injury models. Murine small bowel ulcers were generated by topical serosal acetic acid or subcutaneous indomethacin in C57BL/6J mice. One day later, we began treatment with ZINC40099027 or DMSO, staining the mucosa for phosphorylated FAK and Ki-67 and measuring mucosal ulcer area, serum creatinine, ALT, and body weight at day 4. ZINC40099027 (10–1000 nM) dose-dependently activated FAK phosphorylation, without activating Pyk2-Tyr-402 or Src-Tyr-419. ZINC40099027 did not stimulate proliferation, and stimulated wound closure independently of proliferation. The FAK inhibitor PF-573228 prevented ZINC40099027-stimulated wound closure. In both mouse ulcer models, ZINC40099027accelerated mucosal wound healing. FAK phosphorylation was increased in jejunal epithelium at the ulcer edge, and Ki-67 staining was unchanged in jejunal mucosa. ZINC40099027 serum concentration at sacrifice resembled the effective concentration in vitro. Weight, creatinine and ALT did not differ between groups. Small molecule FAK activators can specifically promote epithelial restitution and mucosal healing and may be useful to treat gut mucosal injury.

Epithelial-mesenchymal plasticity-engaging stemness in an interplay of phenotypes

Cancer is a genetic disease which results in a functional imbalance between tumour-repressive and oncogenic signals. The WHO highlights the burden of this indomitable disease, listing it as the second leading cause of death globally. The major cause of cancer-related death is rarely the effect of the primary tumour itself, but rather, the devastating spread of cancer cells in metastases. Epithelial-mesenchymal plasticity (EMP)-termed as the ability of cells to maintain its plasticity and transit between epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) states-plays a fundamental role in cancer metastasis. These cell transitions allow them migrate from the primary tumour and invade the secondary site. EMP is associated with migration, invasion, colonisation, self-renewal and drug resistance. This review briefly elucidates the mechanism of EMP and the association between cancer stem cells (CSCs) and circulating tumour cells (CTCs), biomarkers and signalling pathways involved in EMP as well as drug resistance and therapeutic targeting.

Emerging roles of aerobic glycolysis in breast cancer

Altered aerobic glycolysis is a well-recognized characteristic of cancer cell energy metabolism, known as the Warburg effect. Even in the presence of abundant oxygen, a majority of tumor cells produce substantial amounts of energy through a high glycolytic metabolism, and breast cancer (BC) is no exception. Breast cancer continues to be the second leading cause of cancer-associated mortality in women worldwide. However, the precise role of aerobic glycolysis in the development of BC remains elusive. Therefore, the present review attempts to address the implication of key enzymes of the aerobic glycolytic pathway including hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK), glucose transporters (GLUTs), together with related signaling pathways including protein kinase B(PI3K/AKT), mammalian target of rapamycin (mTOR) and adenosine monophosphate-activated protein kinase (AMPK) and transcription factors (c-myc, p53 and HIF-1) in the research of BC. Thus, the review of aerobic glycolysis in BC may evoke novel ideas for the BC treatment.

Immunohistochemical Features of Epithelial-Mesenchymal Transition in Feline Oral Squamous Cell Carcinoma

Feline oral squamous cell carcinoma (FOSCC) is an aggressive malignancy with invasive and metastatic behavior. It is poorly responsive to chemotherapy and radiation. Neoplastic epithelial-mesenchymal transition (EMT) portends highly malignant behavior and enhances resistance to therapy. In transitioning to a more malignant phenotype, carcinoma stem cells undergo transformation mediated by expression of proteins, endowing them with mesenchymal properties advantageous to cell survival. The goal of the current study was to identify proteins associated with EMT in FOSCC. This study documents protein expression patterns in 10 FOSCC biopsies and 3 FOSCC cell lines (SCCF1, SCCF2, SCCF3), compatible with an EMT phenotype. As markers of EMT, P-cadherin, N-cadherin, vimentin, nuclear transcription factors Twist and Snail, hypoxia inducible factor 1α (HIF-1α), programmed death ligand 1, and vascular endothelial growth factor D, as well as E-cadherin, were examined using immunohistochemistry, Western blot, and enzyme-linked immunosorbent assay. P-cadherin, Twist, HIF-1α, and programmed death ligand 1 were commonly expressed in biopsies and cell lines. N-cadherin, classically associated with EMT, was not highly expressed, and E-cadherin was coexpressed along with proteins characteristic of EMT in all specimens. Production of vascular endothelial growth factor A by cell lines, a process regulated by HIF-1α expression, was suppressed by the small-molecule inhibitor dasatinib. These data are consistent with EMT in FOSCC and shed light on cellular changes that could contribute to the aggressive behavior of FOSCC.

S100P regulates the collective invasion of pancreatic cancer cells into the lymphatic endothelial monolayer

Lymph node metastasis is an independent prognostic factor in pancreatic cancer. However, the mechanisms of lymph node colonization are unknown. As a mechanism of lymphatic metastasis, it has been reported for other types of cancer that spheroids from tumor cells cause circular chemorepellent‑induced defects (CCIDs) in lymphatic endothelial monolayers. In pancreatic cancer, such mechanisms of metastasis have not been elucidated. The present study evaluated the involvement of this new mechanism of metastasis in pancreatic cancer and investigated the associated factors. In human pancreatic cancer tissue, it was observed that clusters of cancer cells penetrated the wall of lymphatic ducts around the primary tumor. An in vitro co‑culture system was then used to analyze the mechanisms of tumor cell‑mediated disruption of lymphatic vessels. Time‑lapse microscopic imaging revealed that spheroids from pancreatic cancer cells caused circular defects in lymphatic endothelial monolayers. CCID formation ability differed depending on the cell line. Neither aggregation of spheroids nor adhesion to lymphatic endothelial cells (LECs) exhibited a significant correlation with this phenomenon. The addition of supernatant from cultured cancer cells enhanced CCID formation. Microarray analysis revealed that the expression of S100 calcium binding protein P (S100P) was significantly increased when LECs were treated with supernatant from cultured cancer cells. Addition of a S100P antagonist significantly suppressed the migration of LECs and CCID formation. The present findings demonstrated that spheroids from pancreatic cancer cells caused circular defects in lymphatic endothelial monolayers. These CCIDs in pancreatic cancer were partly regulated by S100P, suggesting that S100P may be a promising target to inhibit lymph node metastasis.

Targeting PIN1 exerts potent antitumor activity in pancreatic ductal carcinoma via inhibiting tumor metastasis

The human prolyl isomerase PIN1, best known for its association with carcinogenesis, has recently been indicated in the disease of pancreatic ductal adenocarcinoma (PDAC). However, the functions of PIN1 and the feasibility of targeting PIN1 in PDAC remain elusive. For this purpose, we examined the expression of PIN1 in cancer, related paracarcinoma and metastatic cancer tissues by immunohistochemistry and analyzed the associations with the pathogenesis of PDAC in 173 patients. The functional roles of PIN1 in PDAC were explored in vitro and in vivo using both genetic and chemical PIN1 inhibition. We showed that PIN1 was upregulated in pancreatic cancer and metastatic tissues. High PIN1 expression is significantly association with poor clinicopathological features and shorter overall survival and disease‐free survival. Further stratified analysis showed that PIN1 phenotypes refined prognostication in PDAC. Inhibition of PIN1 expression with RNA interference or with all trans retinoic acid decreased not only the growth but also the migration and invasion of PDAC cells through regulating the key molecules of multiple cancer‐driving pathways, simultaneously resulting in cell cycle arrest and mesenchymal‐epithelial transition in vitro. Furthermore, genetic and chemical PIN1 ablation showed dramatic inhibition of the tumorigenesis and metastatic spread and then reduced the tumor burden in vivo. We provided further evidence for the use of PIN1 as a promising therapeutic target in PDAC. Genetic and chemical PIN1 ablation exerted potent antitumor effects through blocking multiple cancer‐driving pathways in PDAC. More potent and specific PIN1 targeted inhibitors could be exploited to treat this aggressive cancer.

What makes cells move: Requirements and obstacles for leader cells in collective invasion

Most recently, mounting evidence has shown that cancer cells can invade as a cohesive and multicellular group with coordinated movement, which is called collective invasion. In this cohesive cancer cell group, cancer cells at the front of collective invasion are defined as leader cell that are responsible for many aspects of collective invasion, including sensing the microenvironment, determining the invasion direction, modifying the path of invasion and transmitting information to other cells. To fulfill their dispensable roles, leader cells are required to embark on some specific phenotypes with unusual expression of some proteins and it's very important to investigate into these proteins as they may serve as potential therapeutic targets. Here, in this review we will summarize current knowledge on four emerging proteins highly expressed in leader cells including K14, ΔNp63α, Dll4 and cysteine protease cathepsin B (CTSB), with a focus on their important roles in collective invasion and special mechanisms by which they promote collective invasion.

Roles of E-cadherin and Noncoding RNAs in the Epithelial-mesenchymal Transition and Progression in Gastric Cancer

The epithelial–mesenchymal transition (EMT) is thought to be at the root of invasive and metastatic cancer cell spreading. E-cadherin is an important player in this process, which forms the structures that establish and maintain cell–cell interactions. A partial or complete loss of E-cadherin expression in the EMT is presumably mediated by mechanisms that block the expression of E-cadherin regulators and involve the E-cadherin-associated transcription factors. The protein is involved in several oncogenic signaling pathways, such as the Wnt/β-catenin, Rho GTPase, and EGF/EGFR, whereby it plays a role in many tumors, including gastric cancer. Such noncoding transcripts as microRNAs and long noncoding RNAs—critical components of epigenetic control of gene expression in carcinogenesis—contribute to regulation of the E-cadherin function by acting directly or through numerous factors controlling transcription of its gene, and thus affecting not only cancer cell proliferation and metastasis, but also the EMT. This review focuses on the role of E-cadherin and the non-coding RNAs-mediated mechanisms of its expressional control in the EMT during stomach carcinogenesis.

Insights on CTC Biology and Clinical Impact Emerging from Advances in Capture Technology

Circulating tumor cells (CTCs) and circulating tumor microemboli (CTM) have been shown to correlate negatively with patient survival. Actual CTC counts before and after treatment can be used to aid in the prognosis of patient outcomes. The presence of circulating tumor materials (CTMat) can advertise the presence of metastasis before clinical presentation, enabling the early detection of relapse. Importantly, emerging evidence is indicating that cancer treatments can actually increase the incidence of CTCs and metastasis in pre-clinical models. Subsequently, the study of CTCs, their biology and function are of vital importance. Emerging technologies for the capture of CTC/CTMs and CTMat are elucidating vitally important biological and functional information that can lead to important alterations in how therapies are administered. This paves the way for the development of a "liquid biopsy" where treatment decisions can be informed by information gleaned from tumor cells and tumor cell debris in the blood.

Epithelial-Mesenchymal Plasticity in Organotropism Metastasis and Tumor Immune Escape

Most cancer deaths are due to metastasis, and almost all cancers have their preferential metastatic organs, known as “organotropism metastasis”. Epithelial-mesenchymal plasticity has been described as heterogeneous and dynamic cellular differentiation states, supported by emerging experimental evidence from both molecular and morphological levels. Many molecular factors regulating epithelial-mesenchymal plasticity have tissue-specific and non-redundant properties. Reciprocally, cellular epithelial-mesenchymal plasticity contributes to shaping organ-specific pre-metastatic niche (PMN) including distinct local immune landscapes, mainly through secreted bioactive molecular factors. Here, we summarize recent progress on the involvement of tumor epithelial-mesenchymal plasticity in driving organotropic metastasis and regulating the function of different immune cells in organ-specific metastasis.

Biomechanics of Collective Cell Migration in Cancer Progression: Experimental and Computational Methods

Cell migration is essential for regulating many biological processes in physiological or pathological conditions, including embryonic development and cancer invasion. In vitro and in silico studies suggest that collective cell migration is associated with some biomechanical particularities such as restructuring of extracellular matrix (ECM), stress and force distribution profiles, and reorganization of the cytoskeleton. Therefore, the phenomenon could be understood by an in-depth study of cells' behavior determinants, including but not limited to mechanical cues from the environment and from fellow "travelers". This review article aims to cover the recent development of experimental and computational methods for studying the biomechanics of collective cell migration during cancer progression and invasion. We also summarized the tested hypotheses regarding the mechanism underlying collective cell migration enabled by these methods. Together, the paper enables a broad overview on the methods and tools currently available to unravel the biophysical mechanisms pertinent to cell collective migration as well as providing perspectives on future development toward eventually deciphering the key mechanisms behind the most lethal feature of cancer.

Carnosine Suppresses Human Colorectal Cell Migration and Intravasation by Regulating EMT and MMP Expression

Carnosine is an endogenous dipeptide found in the vertebrate skeletal muscles that is usually obtained through the diet. To investigate the mechanism by which carnosine regulates the migration and intravasation of human colorectal cancer (CRC) cells, we used cultured HCT-116 cells as an experimental model in this study. We examined HCT-116 cell migratory and intravasive abilities and expression of epithelial-mesenchymal transition (EMT)-associated molecules and matrix metalloproteinases (MMPs) after carnosine treatment. The results showed that both migration and invasion were inhibited in cells treated with carnosine. We found significant decreases in Twist-1 protein levels and increases in E-cadherin protein levels in HCT-116 cells after carnosine exposure. Although plasminogen activator (uPA) and MMP-9 mRNA and protein levels were decreased, TIMP-1 mRNA and protein levels were increased. Furthermore, the cytosolic levels of phosphorylated I κ B (p-I κ B) and NF- κ B DNA-binding activity were reduced after carnosine treatment. These results indicate that carnosine inhibits the migration and intravasation of human CRC cells. The regulatory mechanism may occur by suppressing NF- κ B activity and modulating MMP and EMT-related gene expression in HCT-116 cells.

EGFR point mutation detection of single circulating tumor cells for lung cancer using a micro-well array

In view of their critical function in metastasis, characterization of single circulating tumor cells (CTCs) can provide important clinical information to monitor tumor progression and guide personal therapy. Single-cell genetic analysis methods based on microfluidics have some inherent shortcomings such as complicated operation, low throughput, and expensive equipment requirements. To overcome these barriers, we developed a simple and open micro-well array containing 26,208 units for either nuclear acids or single-cell genetic analysis. Through modification of the polydimethylsiloxane surface and optimization of chip packaging, we addressed protein adsorption and solution evaporation for PCR amplification on a chip. In the detection of epidermal growth factor receptor (EGFR) exon gene 21, this micro-well array demonstrated good linear correlation at a DNA concentration from 1 × 10¹ to 1 × 10⁵ copies/μL (R² = 0.9877). We then successfully integrated cell capture, lysis, PCR amplification, and signal read-out on the micro-well array, enabling the rapid and simple genetic analysis of single cells. This device was used to detect duplex EGFR mutation genes of lung cancer cell lines (H1975 and A549 cells) and normal leukocytes, demonstrating the ability to perform high-throughput, massively parallel duplex gene analysis at the single-cell level. Different types of point mutations (EGFR-L858R mutation or EGFR-T790M mutation) were detected in single H1975 cells, further validating the significance of single-cell level gene detection. In addition, this method showed a good performance in the heterogeneity detection of individual CTCs from lung cancer patients, required for micro-invasive cancer monitoring and treatment selection.

Epithelial-to-mesenchymal transition: lessons from development, insights into cancer and the potential of EMT-subtype based therapeutic intervention

Epithelial-to-mesenchymal transition (EMT) is a fundamental developmental process wherein polarized epithelial cells lose their junctional architecture and apical-basal polarity to become motile mesenchymal cells, and there is emerging evidence for its role in propagating tumor dissemination. While many multifaceted nodules converge onto the EMT program, in this review we will highlight the fundamental biology of the signaling schemas that enable EMT. In many cancers, the property of tumor dissemination and metastasis is closely associated with re-enabling developmental properties such as EMT. We discuss the molecular complexity of the tumor heterogeneity in terms of EMT-based gene expression molecular subtypes, and the rewiring of critical signaling nodules in the subtypes displaying higher degrees of EMT can be therapeutically exploited. Specifically in the context of a deadly malignancy such as ovarian cancer where there are no defined mutations or limited biomarkers for developing targeted therapy or personalized medicine, we highlight the importance of identifying EMT-based subtypes that will improve therapeutic intervention. In ovarian cancer, the poor prognosis mesenchymal 'Mes' subtype presents with amplified signaling of the receptor tyrosine kinase (RTK) AXL, extensive crosstalk with other RTKs such as cMET, EGFR and HER2, and sustained temporal activation of extracellular-signal regulated kinase (ERK) leading to induction of EMT transcription factor Slug, underscoring a pathway addiction in Mes that can be therapeutically targeted. We will further examine the emergence of therapeutic modalities in these EMT subtypes and finally conclude with potential interdisciplinary biophysical methodologies to provide additional insights in deciphering the mechanistic and biochemical aspects of EMT. This review intends to provide an overview of the cellular and molecular changes accompanying epithelial-to-mesenchymal transition (EMT) in development and the requisition of this evolutionarily conserved pathway in cancer progression and metastatic disease. Specifically, in a heterogeneous disease such as ovarian cancer lacking defined targetable mutations, the identification of EMT-based subtypes has opened avenues to tailor precision personalized medicine. In particular, using the oncogenic RTK AXL as an example, we will highlight how this classification enables EMT-subtype specific identification of targets that could improve treatment options for patients and how there is a growing need for biophysical approaches to model dynamic processes such as EMT.

Epithelial-mesenchymal Transition Phenotypes in Vertebral Metastases of Lung Cancer

Vertebral metastases of non-small cell lung cancer (NSCLC) are frequently diagnosed in the metastatic setting and are commonly identified in the thoracic vertebrae in patients. Treatment of NSCLC bone metastases, which are often multiple, is palliative, and the median survival times are 3 to 6 months. We have characterized spontaneous vertebral metastases in a brain metastases model of NSCLC and correlated these findings with epithelial-mesenchymal transition (EMT). Brain metastases were established in athymic nude mice following intracardiac injection of brain-seeking adenocarcinoma NSCLC cells. Thirty-nine percent of mice (14/36) developed spontaneous vertebral metastases, spinal cord compression, and hind-limb paralysis. Vertebral metastases consisted of an adenocarcinoma phenotype with neoplastic epithelial cells arranged in cords or acini and a mesenchymal phenotype with spindloid neoplastic cells arranged in bundles and streams. Quantitative and qualitative immunohistochemical and immunofluorescence assays demonstrated an increase in vimentin expression compared to cytokeratin expression in vertebral metastases. A correlation with EMT was supported by an increase in CD44 in vertebral metastases and parenchymal metastases. These data demonstrate a translational lung cancer metastasis model with spontaneous vertebral metastasis. The mesenchymal and epithelial phenotype of these spontaneous metastases coupled with EMT provide a conduit to improve drug delivery and overall patient survival.

Inhibition of LONP1 Suppresses Pancreatic Cancer Progression Via c-Jun N-Terminal Kinase Pathway-Meditated Epithelial-Mesenchymal Transition

OBJECTIVE

The aim of this study was to investigate the role of LONP1 in the progression of pancreatic cancer.

METHODS

Lentivirus was used to silence LONP1 in PANC-1 cells. Colony formation assay, cell counting kit (CCK8) assay, cell scratch-wound assay, and transwell assay were used to assess the effects of our strategy on inhibiting cancer growth, migration, and invasion. Protein expression was detected by Western blot analysis.

RESULTS

The expression of LONP1 in pancreatic carcinoma tissues was higher than that in adjacent normal pancreatic tissues. Downregulation of LONP1 suppressed the proliferation, migration, and invasion of PANC-1 cells. Knockdown of LONP1 in PANC-1 cells inhibited epithelial-mesenchymal transition and matrix metalloprotein (MMP) 2/9 by downregulation of vimentin, snail, slug, MMP2, and MMP9 and upregulation of claudin-1. The c-Jun N-terminal kinase pathway was inactivated in LONP1 knockdown PANC-1 cells. Activation of the c-Jun N-terminal kinase pathway by anisomycin treatment significantly reversed the changes in epithelial-mesenchymal transition markers and MMP2/9 induced by ablation of LONP1 in PANC-1 cells.

CONCLUSIONS

LONP1 plays a vital role in the proliferation and metastasis of pancreatic cancer, which provides a potential therapeutic target for the treatment of pancreatic cancer.