Snail and Slug collaborate on EMT and tumor metastasis through miR-101-mediated EZH2 axis in oral tongue squamous cell carcinoma

MK2 promotes p16 negative head and neck cancer migration, invasion, and metastasis

For patients with locally advanced, p16-negative head and neck squamous cell carcinoma (HNSCC), overall survival remains poor due to primary locoregional failure and distant metastasis following curative therapy. We aimed to understand how MAPKAPK2 (MK2) regulates HNSCC tumor cell migration and invasion, important first steps in cancer metastases. The TCGA database and HNSCC tissue microarrays were used to show that MK2 expression was associated with more advanced cancers and faster cancer recurrence rates. We observed that silencing of tumor MK2 in human cell lines (shRNA) caused a significant reduction in tumor cell migration-invasion in a complex HNSCC microphysiologic system used to recapitulate the tumor microenvironment. Murine cells (Ly2) with MK2 silenced (CRISPR-Cas9) also demonstrated reduced migration and invasion using 2D and 3D monoculture cell migration-invasions assays. Ly2 cells are orthotopic p16-negative murine metastatic cells that spontaneously metastasize, and we observed that MK2 inhibition via genetic (Cas9/CRISPR) or pharmacologic (PF-3644022) methods led to a significant reduction in the number of circulating tumor cells, fewer lymph node and lung metastases, and MK2 inhibited mice showed improved overall survival. Our findings suggest that HNSCC MK2 regulates tumor cell migration-invasion and may be a promising therapeutic target to reduce metastases.

miRNAs in oral cancer; diagnostic and prognostic roles

Oral cancer (OC) has become increasingly prevalent in recent years, making it one of the most often occurring types of cancer in patients. The clinical identification of OC is usually a time-consuming procedure, and the outlook for individuals with OC is generally unfavorable, as no particular biomarkers have been established to far. The main risk factors linked to OC are high levels of tobacco and alcohol intake, together with a reduced occurrence of viral infections, such as human papillomavirus. Furthermore, there is evidence suggesting that genetic characteristics that can be passed down from parents to offspring play a role in increasing the likelihood of getting ovarian cancer. MicroRNAs (miRNAs) are brief RNA molecules that do not code for proteins and have the ability to either repress or promote the growth of tumors during cancer development. They have been discovered to control multiple signaling pathways within cells, and their abnormal regulation has been demonstrated to be crucial in initiating and furthering the development of cancer. Additionally, they have the ability to either facilitate or impede the entire multi-stage process of cancer metastasis, including epithelial-mesenchymal transition (EMT), migration, and invasion, by selectively targeting essential genes involved in these pathways. Several microRNAs have the ability to regulate gene expression through various ways. In addition, like other types of cancer, OC has shown alterations in the expression of miRNAs, and certain miRNAs may have the ability to be used for diagnosis and treatment. The investigation of these miRNA could perhaps result in advancements in the specified instances of OC.

Expression profile, regulatory mechanism and prognostic potential of MBNL2 in esophageal squamous cell carcinoma

Background

It remains to refresh the understanding about the pathogenic mechanism of esophageal squamous cell carcinoma (ESCC). This study aimed to profile the expression of muscleblind like protein 2 (MBNL2), as well as its associations with ESCC behaviors.

Methods

Bioinformatic tools were used to mine The Cancer Genome Atlas (TCGA) database for the expression data of MBNL2 in ESCC. The expression of MBNL2 in tissue microarray of 179 ESCC patients was determined by immunohistochemistry (IHC), and the relationship of MBNL2 with patients' clinical and pathological characteristics was analyzed. The expression of MBNL2 was tested in fresh ESCC and adjacent normal tissues in vitro. Experiments about cellular invasion, migration and proliferation were performed to detect the impacts of silencing MBNL2 on the biological behaviors of ESCC, and the positive results were checked in vivo.

Results

In the TCGA database, the expression of MBNL2 in ESCC was higher than that in adjacent tissues (P<0.05). The protein level of MBNL2 in the tissue microarray of 179 ESCC patients was positively correlated with tumor stage and lymph node metastasis, and negatively correlated with the prognosis of patients. The expression of MBNL2 was significantly upregulated in five fresh ESCC tissues, compared to that in adjacent tissues. In functional experiments, knocking down MBNL2 significantly inhibited the migration and invasion of ESCC cell lines KYSE150 and Eca109, but had no significant effect on their proliferation. Finally, silencing MBNL2 inhibited the epithelial-mesenchymal transition (EMT) of ESCC cells, as evidenced by the upregulation of E-cadherin, the downregulation of Snail and Slug.

Conclusions

MBNL2 is highly expressed in ESCC and associated with its Tumor Node Metastasis (TNM) stage, lymph node metastasis and prognosis. MBNL2 may promote ESCC progression through facilitating EMT.

Upregulation of the MAP2K4 gene triggers endothelial-mesenchymal transition in COVID-19

BACKGROUND

SARS-CoV-2 infection is marked by an excessive inflammatory response, leading to elevated production of pro-inflammatory cytokines through activation of intracellular pathways like mitogen-activated protein kinase (MAPK). Viruses can use the MAPK signaling pathway to their advantage, but the relationship of this pathway to the severe SARS-CoV-2 period has not been fully elucidated. MAP2K4 is involved in the MAPK signaling pathway and affects cellular processes such as cell-cell junction, cell proliferation, differentiation and apoptosis.

METHODS AND RESULTS

In this study, we sought to determine the associated biomarkers that are involved in the MAP2K4 pathway and elucidate its possible roles in terms of some clinical features associated with COVID-19. We evaluated the expressions of MAP2K4, SNAI1, SLUG, ZEB1 and E-Cadherin. For this purpose, we prospectively recruited 66 individuals, 39 of whom were women and had a mean age of 65 years. The results revealed that MAP2K4 upregulation increased SNAI1 gene expression level whereas E- Cadherin level was decreased in SARS-CoV-2 positive participants. In addition, negative correlations were determined with PLT, Lymphocyte and CKMB and E- Cadherin levels in positive participants. We also observed a negative correlation between the MAP2K4 and AST, and a positive correlation between SLUG and BUN, ZEB1 and CK.

CONCLUSIONS

We conclude that SARS-CoV-2 infection triggers fibrosis by increasing MAP2K4 regulation. Additionally, this is the first study to demonstrate the possible contribution of MAP2K4 in influencing COVID-19 clinical features, which may be relevant for identifying COVID-19 positive participants with severe complications.

Intersecting pathways: The role of hybrid E/M cells and circulating tumor cells in cancer metastasis and drug resistance

Cancer metastasis and therapy resistance are intricately linked with the dynamics of Epithelial-Mesenchymal Transition (EMT) and Circulating Tumor Cells (CTCs). EMT hybrid cells, characterized by a blend of epithelial and mesenchymal traits, have emerged as pivotal in metastasis and demonstrate remarkable plasticity, enabling transitions across cellular states crucial for intravasation, survival in circulation, and extravasation at distal sites. Concurrently, CTCs, which are detached from primary tumors and travel through the bloodstream, are crucial as potential biomarkers for cancer prognosis and therapeutic response. There is a significant interplay between EMT hybrid cells and CTCs, revealing a complex, bidirectional relationship that significantly influences metastatic progression and has a critical role in cancer drug resistance. This resistance is further influenced by the tumor microenvironment, with factors such as tumor-associated macrophages, cancer-associated fibroblasts, and hypoxic conditions driving EMT and contributing to therapeutic resistance. It is important to understand the molecular mechanisms of EMT, characteristics of EMT hybrid cells and CTCs, and their roles in both metastasis and drug resistance. This comprehensive understanding sheds light on the complexities of cancer metastasis and opens avenues for novel diagnostic approaches and targeted therapies and has significant advancements in combating cancer metastasis and overcoming drug resistance.

The evolving roles of Wnt signaling in stem cell proliferation and differentiation, the development of human diseases, and therapeutic opportunities

The evolutionarily conserved Wnt signaling pathway plays a central role in development and adult tissue homeostasis across species. Wnt proteins are secreted, lipid-modified signaling molecules that activate the canonical (β-catenin dependent) and non-canonical (β-catenin independent) Wnt signaling pathways. Cellular behaviors such as proliferation, differentiation, maturation, and proper body-axis specification are carried out by the canonical pathway, which is the best characterized of the known Wnt signaling paths. Wnt signaling has emerged as an important factor in stem cell biology and is known to affect the self-renewal of stem cells in various tissues. This includes but is not limited to embryonic, hematopoietic, mesenchymal, gut, neural, and epidermal stem cells. Wnt signaling has also been implicated in tumor cells that exhibit stem cell-like properties. Wnt signaling is crucial for bone formation and presents a potential target for the development of therapeutics for bone disorders. Not surprisingly, aberrant Wnt signaling is also associated with a wide variety of diseases, including cancer. Mutations of Wnt pathway members in cancer can lead to unchecked cell proliferation, epithelial-mesenchymal transition, and metastasis. Altogether, advances in the understanding of dysregulated Wnt signaling in disease have paved the way for the development of novel therapeutics that target components of the Wnt pathway. Beginning with a brief overview of the mechanisms of canonical and non-canonical Wnt, this review aims to summarize the current knowledge of Wnt signaling in stem cells, aberrations to the Wnt pathway associated with diseases, and novel therapeutics targeting the Wnt pathway in preclinical and clinical studies.

Polycomb repressive complex 2 and its core component EZH2: potential targeted therapeutic strategies for head and neck squamous cell carcinoma

The polycomb group (PcG) comprises a set of proteins that exert epigenetic regulatory effects and play crucial roles in diverse biological processes, ranging from pluripotency and development to carcinogenesis. Among these proteins, enhancer of zeste homolog 2 (EZH2) stands out as a catalytic component of polycomb repressive complex 2 (PRC2), which plays a role in regulating the expression of homologous (Hox) genes and initial stages of x chromosome inactivation. In numerous human cancers, including head and neck squamous cell carcinoma (HNSCC), EZH2 is frequently overexpressed or activated and has been identified as a negative prognostic factor. Notably, EZH2 emerges as a significant gene involved in regulating the STAT3/HOTAIR axis, influencing HNSCC proliferation, differentiation, and promoting metastasis by modulating related oncogenes in oral cancer. Currently, various small molecule compounds have been developed as inhibitors specifically targeting EZH2 and have gained approval for treating refractory tumors. In this review, we delve into the epigenetic regulation mediated by EZH2/PRC2 in HNSCC, with a specific focus on exploring the potential roles and mechanisms of EZH2, its crucial contribution to targeted drug therapy, and its association with cancer markers and epithelial-mesenchymal transition. Furthermore, we aim to unravel its potential as a therapeutic strategy for oral squamous cell carcinoma.

MicroRNA Expression Profiles in Human Samples and Cell Lines Revealed Nine miRNAs Associated with Cisplatin Resistance in High-Grade Serous Ovarian Cancer

Metastasis and drug resistance are major contributors to cancer-related fatalities worldwide. In ovarian cancer (OC), a staggering 70% develop resistance to the front-line therapy, cisplatin. Despite proposed mechanisms, the molecular events driving cisplatin resistance remain unclear. Dysregulated microRNAs (miRNAs) play a role in OC initiation, progression, and chemoresistance, yet few studies have compared miRNA expression in OC samples and cell lines. This study aimed to identify key miRNAs involved in the cisplatin resistance of high-grade-serous-ovarian-cancer (HGSOC), the most common gynecological malignancy. MiRNA expression profiles were conducted on RNA isolated from formalin-fixed-paraffin-embedded human ovarian tumor samples and HGSOC cell lines. Nine miRNAs were identified in both sample types. Targeting these with oligonucleotide miRNA inhibitors (OMIs) reduced proliferation by more than 50% for miR-203a, miR-96-5p, miR-10a-5p, miR-141-3p, miR-200c-3p, miR-182-5p, miR-183-5p, and miR-1206. OMIs significantly reduced migration for miR-183-5p, miR-203a, miR-296-5p, and miR-1206. Molecular pathway analysis revealed that the nine miRNAs regulate pathways associated with proliferation, invasion, and chemoresistance through PTEN, ZEB1, FOXO1, and SNAI2. High expression of miR-1206, miR-10a-5p, miR-141-3p, and miR-96-5p correlated with poor prognosis in OC patients according to the KM plotter database. These nine miRNAs could be used as targets for therapy and as markers of cisplatin response.

PAK5 potentiates slug transactivation of N-cadherin to facilitate metastasis of renal cell carcinoma

Renal cell carcinoma (RCC) is an aggravating cancer with a poor prognosis and a high rate of metastasis. PAK5, a p21-activated kinases, has shown to be overexpressed in a variety of cancers, including RCC. In previous studies, we discovered that PAK5 regulates cell migration and invasion in RCC cell lines. However, the underlying mechanisms remain obscure. In this study, we consolidated that PAK5 confers a pro-metastatic phenotype RCC cells in vitro and exacerbates metastasis in vivo. High PAK5 expression was associated with an advanced TNM stage and a lower overall survival. Furthermore, PAK5 increases the expression level of N-cadherin. In terms of mechanism, PAK5 bound to Slug and phosphorylated it at serine 87. As a result, phosphorylated Slug transactivated N-cadherin, accelerating the epithelial-mesenchymal transition. Collectively, Slug is a novel PAK5 substrate, and PAK5-mediated phosphorylation of Slug-S87 increases N-cadherin and the pro-metastatic phenotype of RCC, implying that phosphorylated Slug-S87 could be a therapeutic target in progressive RCC.

MiRNA-related metastasis in oral cancer: moving and shaking

Across the world, oral cancer is a prevalent tumor. Over the years, both its mortality and incidence have grown. Oral cancer metastasis is a complex process involving cell invasion, migration, proliferation, and egress from cancer tissue either by lymphatic vessels or blood vessels. MicroRNAs (miRNAs) are essential short non-coding RNAs, which can act either as tumor suppressors or as oncogenes to control cancer development. Cancer metastasis is a multi-step process, in which miRNAs can inhibit or stimulate metastasis at all stages, including epithelial-mesenchymal transition, migration, invasion, and colonization, by targeting critical genes in these pathways. On the other hand, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two different types of non-coding RNAs, can regulate cancer metastasis by affecting gene expression through cross-talk with miRNAs. We reviewed the scientific literature (Google Scholar, Scopus, and PubMed) for the period 2000-2023 to find reports concerning miRNAs and lncRNA/circRNA-miRNA-mRNA networks, which control the spread of oral cancer cells by affecting invasion, migration, and metastasis. According to these reports, miRNAs are involved in the regulation of metastasis pathways either by directly or indirectly targeting genes associated with metastasis. Moreover, circRNAs and lncRNAs can induce or suppress oral cancer metastasis by acting as competing endogenous RNAs to inhibit the effect of miRNA suppression on specific mRNAs. Overall, non-coding RNAs (especially miRNAs) could help to create innovative therapeutic methods for the control of oral cancer metastases.

Overexpression of E-Cadherin Is a Favorable Prognostic Biomarker in Oral Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

Oral squamous cell carcinoma (OSCC) is characterized by poor survival, mostly due to local invasion, loco-regional recurrence, and metastasis. Given that the weakening of cell-to-cell adhesion is a feature associated with the migration and invasion of cancer cells, different studies have explored the prognostic utility of cell adhesion molecules such as E-cadherin (E-cad). This study aims to summarize current evidence in a meta-analysis, focusing on the prognostic role of E-cad in OSCC. To find studies meeting inclusion criteria, Scopus, Web of Science, EMBASE, Medline, and OpenGrey databases were systematically assessed and screened. The selection process led to 25 studies, which were considered eligible for inclusion in the meta-analysis, representing a sample of 2553 patients. E-cad overexpression was strongly associated with longer overall survival (OS) with Hazard Ratio (HR)  = 0.41 95% confidence interval (95% CI) (0.32-0.54); p < 0.001 and disease-free survival with HR 0.47 95% CI (0.37-0.61); p < 0.001. In terms of OS, patients with tongue cancer experienced better survivability when expressing E-cad with HR 0.28 95% CI (0.19-0.43); p < 0.001. Globally, our findings indicate the prognostic role of the immunohistochemical assessment of E-cad in OSCC and its expression might acquire a different role based on the oral cavity subsites.

Bioinformatics based exploration of hsa-miR-194-5p regulation of CHD4 through PI3K/AKT signal pathway to enhance tumor resistance to apoptosis due to loss of nests and participate in poor prognosis of oral squamous cell carcinoma

Background

Recent evidence shows that CHD4 is involved in a variety of biological events of tumors. Our aim was to investigate the correlation between CHD4 and oral squamous cell carcinoma (OSCC).

Methods

After CHD4 was screened as a differentially expressed gene in The Cancer Genome Atlas (TGCA) database, the correlations of its expression level with the clinical parameters and prognosis of patients with OSCC were analyzed. The outcomes of the multivariate analysis were used to construct a nomogram, and the accuracy of the model was evaluated with the calibration curve. The GeneMANIA and STRING databases were used to generate network diagrams depicting interactions of genes with CHD4, and heat maps of genes co-expressed with CHD4 were generated using the TCGA database. TargetScan was then used to look into the miRNAs that interact with the 3' untranslated region of CHD4 mRNA. Finally, GSEA enrichment analysis was used to explore the possible mechanism.

Results

The differentially expressed molecule CHD4 was screened by TCGA database for OSCC. CHD4 was overexpressed in OSCC tumor tissues, and OSCC patients with low expression of CHD4 have better OS and DSS. The nomogram had a C-index of 0.575 (0.548-0.602), which indicated some degree of predictive reliability. CHD4 has certain correlation with exons of OSCC related genes, including TP53, NOTCH1, CASP8, PTEN, TP63, ANXA1, CDH1, CTNNB1, GDF15 and EGFR. According to the TargetScan database, hsa-miR-194-5p is the miRNA that regulates CHD4 upstream the most. GSEA analysis showed that CHD4 may participate in the poor prognosis of OSCC by participating in PI3K/AKT pathway, protein adhesion regulation, MAPK pathway, cytokine and inflammatory response regulation, angiogenesis and platelet regulation.

Conclusions

The decreased expression of CHD4 may indicate a better prognosis in OSCC patients and could serve as a novel predictive biomarker for OSCC. Also, hsa-miR-194-5p was found to contribute to the poor prognosis of OSCC by regulating CHD4 and enhancing tumor anoikis resistance via the PI3K/AKT signaling pathway. These findings suggest that CHD4 might be a therapeutic target for the effective treatment of OSCC.

Immunohistochemical expression of E-cadherin, N-cadherin and Snail/slug in ameloblastoma

CONTEXT

Ameloblastoma is the most common odontogenic tumour and its histomorphological distinction into growth patterns and variants, does not accurately convey information about its biologic aggressiveness. Expression of epithelial mesenchymal transition (EMT) markers, which have been implicated in its etiogenesis, might assist in delineating aggressiveness across variants. This may help in formulating appropriate treatment modalities for its management AIMS: To determine expression of SNAIL/SLUG and ECAD/NCAD in tumour cells in clinical and histological subtypes of ameloblastoma and to establish any association between the immunostaining profile and the biologic behaviour of histologic types of ameloblastoma.

SETTINGS/DESIGN

This is a retrospective study conducted to evaluate the immunoprofile of selected clinical subtypes and histological variants to EMT factors via immunostaining to SLUG and ECAD/NCAD antibodies. Mean aggregate scores for each antibody per variant was analyzed using ANOVA or Kruskal-Wallis test when appropriate. Agreement between AR and SR regions was correlated using Spearman's correlation co-efficient.

RESULTS

A higher staining SLUG intensity in the stellate reticulum (SR) like areas relative to the ameloblast like areas (AR) was observed, without concomitant E-cadherin repression or elimination. However, a direct relationship between SLUG and N-cadherin was observed.

CONCLUSION

Expression of SLUG in the SR like areas can be utilized to predict the biologic behavior of specific clinico-histological variants, however its mechanism via alterations in cadherin switching is equivocal.

Cooperative RNA degradation stabilizes intermediate epithelial-mesenchymal states and supports a phenotypic continuum

Multiple intermediate epithelial-mesenchymal transition (EMT) states reflecting hybrid epithelial and mesenchymal phenotypes were observed in physiological and pathological conditions. Previous theoretical models explaining multiple EMT states rely on regulatory loops involving transcriptional feedback, which produce three or four attractors. This is incompatible with the observed continuum-like EMT spectrum. Here, we used mass-action-based models to describe post-transcriptional regulations, finding that cooperative RNA degradation via multiple microRNA binding sites can generate four-attractor systems without transcriptional feedback. Furthermore, the newly identified intermediates-enabling circuits are common in the EMT regulatory network, and they can synergize with transcriptional feedback to support phenotypic continuum. Finally, our model predicted a role of miR-101 in multistate EMT, and we identified evidence from single-cell RNA-sequencing data that support the prediction. Our work reveals a previously unknown role of cooperative RNA degradation and microRNAs in EMT, providing a framework that can bridge the gap between mechanistic models and single-cell experiments.

Biological and Clinical Aspects of Metastatic Spinal Tumors

Simple Summary

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Our literature review aimed to describe the up-to-date knowledge about the molecular pathways and biomarkers engaged in the spine’s metastatic processes. Moreover, we described current data regarding bone-targeted treatment, the emerging targeted therapies, radiotherapy, and immunotherapy used for the treatment of spine metastases. We hope that knowledge comprehensively presented in our review will contribute to the development of novel drugs targeting specific biomarkers and pathways. The more we learn about the molecular aspects of cancer metastasis, the easier it will be to look for treatment methods that will allow us to precisely kill tumor cells.

Abstract

Spine metastases are a common life-threatening complication of advanced-stage malignancies and often result in poor prognosis. Symptomatic spine metastases develop in the course of about 10% of malignant neoplasms. Therefore, it is essential for contemporary medicine to understand metastatic processes in order to find appropriate, targeted therapeutic options. Thanks to continuous research, there appears more and more detailed knowledge about cancer and metastasis, but these transformations are extremely complicated, e.g., due to the complexity of reactions, the variety of places where they occur, or the participation of both tumor cells and host cells in these transitions. The right target points in tumor metastasis mechanisms are still being researched; that will help us in the proper diagnosis as well as in finding the right treatment. In this literature review, we described the current knowledge about the molecular pathways and biomarkers engaged in metastatic processes involving the spine. We also presented a current bone-targeted treatment for spine metastases and the emerging therapies targeting the discussed molecular mechanisms.

Snail maintains the stem/progenitor state of skin epithelial cells and carcinomas through the autocrine effect of matricellular protein Mindin

Preservation of a small population of cancer stem cells (CSCs) within a heterogeneous carcinoma serves as a paradigm to understand how select cells in a tissue maintain their undifferentiated status. In both embryogenesis and cancer, Snail has been correlated with stemness, but the molecular underpinning of this phenomenon remains largely ill-defined. In models of cutaneous squamous cell carcinoma (cSCC), we discovered a non-epithelial-mesenchymal transition function for the transcription factor Snail in maintaining the stemness of epidermal keratinocytes. Snail-expressing cells secrete the matricellular protein Mindin, which functions in an autocrine fashion to activate a Src-STAT3 pathway to reinforce their stem/progenitor phenotype. This pathway is activated by the engagement of Mindin with the leukocyte-specific integrin, CD11b (ITGAM), which is also unexpectedly expressed by epidermal keratinocytes. Interestingly, disruption of this signaling module in human cSCC attenuates tumorigenesis, suggesting that targeting Mindin would be a promising therapeutic approach to hinder cancer recurrence.

The Role of Hsp27 in Chemotherapy Resistance

Heat shock protein (Hsp)-27 is a small-sized, ATP-independent, chaperone molecule that is overexpressed under conditions of cellular stress such as oxidative stress and heat shock, and protects proteins from unfolding, thus facilitating proteostasis and cellular survival. Despite its protective role in normal cell physiology, Hsp27 overexpression in various cancer cell lines is implicated in tumor initiation, progression, and metastasis through various mechanisms, including modulation of the SWH pathway, inhibition of apoptosis, promotion of EMT, adaptation of CSCs in the tumor microenvironment and induction of angiogenesis. Investigation of the role of Hsp27 in the resistance of various cancer cell types against doxorubicin, herceptin/trastuzumab, gemcitabine, 5-FU, temozolomide, and paclitaxel suggested that Hsp27 overexpression promotes cancer cell survival against the above-mentioned chemotherapeutic agents. Conversely, Hsp27 inhibition increased the efficacy of those chemotherapy drugs, both in vitro and in vivo. Although numerous signaling pathways and molecular mechanisms were implicated in that chemotherapy resistance, Hsp27 most commonly contributed to the upregulation of Akt/mTOR signaling cascade and inactivation of p53, thus inhibiting the chemotherapy-mediated induction of apoptosis. Blockage of Hsp27 could enhance the cytotoxic effect of well-established chemotherapeutic drugs, especially in difficult-to-treat cancer types, ultimately improving patients' outcomes.

SNHG17/miR-384/ELF1 axis promotes cell growth by transcriptional regulation of CTNNB1 to activate Wnt/β-catenin pathway in oral squamous cell carcinoma

Increasing evidence proved the abnormal expression of long non-coding RNAs (lncRNAs) in various human malignancies, including oral squamous cell carcinoma (OSCC). Nevertheless, limited explorations concern the role of lncRNA small nucleolar RNA host gene 17 (SNHG17) in OSCC. Herein, SNHG17 was disclosed to be remarkably upregulated in OSCC cell lines and promoted OSCC cell growth. Further mechanistic studies, including DNA/RNA pull down, RIP, ChIP, and luciferase reporter gene assays, were conducted. It was confirmed that Wnt/β-catenin signaling pathway was involved in the SNHG17-mediated OSCC cell growth. Moreover, E74 like ETS transcription factor 1 (ELF1) was identified as the transcription activator of CTNNB1 (β-catenin mRNA) in OSCC. Inspired by competing for endogenous RNAs (ceRNAs) network, we were pleasantly surprised to find that SNHG17 and ELF1 functioned as ceRNAs in OSCC via competitively binding to microRNA-384 (miR-384). By using rescue assays, we revealed that SNHG17 facilitated OSCC cell growth through modulating miR-384/ELF1 axis. Importantly, we certified that ELF1 was indispensable for SNHG17-affected OSCC progression. Collectively, it can be concluded that SNHG17/miR-384/ELF1 axis contributed to OSCC cell growth via promoting CTNNB1 expression, thus activating Wnt/β-catenin signaling pathway.

Metastatic EMT Phenotype Is Governed by MicroRNA-200-Mediated Competing Endogenous RNA Networks

Epithelial–mesenchymal transition (EMT) is a fundamental physiologically relevant process that occurs during morphogenesis and organ development. In a pathological setting, the transition from epithelial toward mesenchymal cell phenotype is hijacked by cancer cells, allowing uncontrolled metastatic dissemination. The competing endogenous RNA (ceRNA) hypothesis proposes a competitive environment resembling a large-scale regulatory network of gene expression circuits where alterations in the expression of both protein-coding and non-coding genes can make relevant contributions to EMT progression in cancer. The complex regulatory diversity is exerted through an array of diverse epigenetic factors, reaching beyond the transcriptional control that was previously thought to single-handedly govern metastatic dissemination. The present review aims to unravel the competitive relationships between naturally occurring ceRNA transcripts for the shared pool of the miRNA-200 family, which play a pivotal role in EMT related to cancer dissemination. Upon acquiring more knowledge and clinical evidence on non-genetic factors affecting neoplasia, modulation of the expression levels of diverse ceRNAs may allow for the development of novel prognostic/diagnostic markers and reveal potential targets for the disruption of cancer-related EMT.

Combined delivery of salinomycin and docetaxel by dual-targeting gelatinase nanoparticles effectively inhibits cervical cancer cells and cancer stem cells

Intra-tumor heterogeneity is widely accepted as one of the key factors, which hinders cancer patients from achieving full recovery. Especially, cancer stem cells (CSCs) may exhibit self-renewal capacity, which makes it harder for complete elimination of tumor. Therefore, simultaneously inhibiting CSCs and non-CSCs in tumors becomes a promising strategy to obtain sustainable anticancer efficacy. Salinomycin (Sal) was reported to be critical to inhibit CSCs. However, the poor bioavailability and catastrophic side effects brought about limitations to clinical practice. To solve this problem, we previously constructed gelatinase-stimuli nanoparticles composed of nontoxic, biocompatible polyethylene glycol-polycaprolactone (PEG-PCL) copolymer with a gelatinase-cleavable peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG) inserted between the two blocks of the copolymer. By applying our "smart" gelatinase-responsive nanoparticles for Sal delivery, we have demonstrated specific accumulation in tumor, anti-CSCs ability and reduced toxicity of Sal-NPs in our previous study. In the present study, we synthesized Sal-Docetaxel-loaded gelatinase-stimuli nanoparticles (Sal-Doc NP) and confirmed single emulsion as the optimal method of producing Sal-Doc NPs (Sal-Doc SE-NP) in comparison with nanoprecipitation. Sal-Doc SE-NPs inhibited both CSCs and non-CSCs in mice transplanted with cervical cancer, and might be associated with enhanced restriction of epithelial-mesenchymal transition (EMT) pathway. Besides, the tumorigenic capacity and growing speed were obviously suppressed in Sal-Doc-SE-NPs-treated group in rechallenge experiment. Our results suggest that Sal-Doc-loaded gelatinase-stimuli nanoparticles could be a promising strategy to enhance antitumor efficacy and reduce side effects by simultaneously suppressing CSCs and non-CSCs.

Mitogen-activated protein kinase-activated protein kinase-2 (MK2) and its role in cell survival, inflammatory signaling, and migration in promoting cancer

Cancer and the immune system share an intimate relationship. Chronic inflammation increases the risk of cancer occurrence and can also drive inflammatory mediators into the tumor microenvironment enhancing tumor growth and survival. The p38 MAPK pathway is activated both acutely and chronically by stress, inflammatory chemokines, chronic inflammatory conditions, and cancer. These properties have led to extensive efforts to find effective drugs targeting p38, which have been unsuccessful. The immediate downstream serine/threonine kinase and substrate of p38 MAPK, mitogen-activated-protein-kinase-activated-protein-kinase-2 (MK2) protects cells against stressors by regulating the DNA damage response, transcription, protein and messenger RNA stability, and motility. The phosphorylation of downstream substrates by MK2 increases inflammatory cytokine production, drives an immune response, and contributes to wound healing. By binding directly to p38 MAPK, MK2 is responsible for the export of p38 MAPK from the nucleus which gives MK2 properties that make it unique among the large number of p38 MAPK substrates. Many of the substrates of both p38 MAPK and MK2 are separated between the cytosol and nucleus and interfering with MK2 and altering this intracellular translocation has implications for the actions of both p38 MAPK and MK2. The inhibition of MK2 has shown promise in combination with both chemotherapy and radiotherapy as a method for controlling cancer growth and metastasis in a variety of cancers. Whereas the current data are encouraging the field requires the development of selective and well tolerated drugs to target MK2 and a better understanding of its effects for effective clinical use.

TPM3 mediates epithelial-mesenchymal transition in esophageal cancer via MMP2/MMP9

Background

Esophageal cancer (EC) is a malignant tumor with high mortality. Correlations have been found between the expression level of tropomyosin 3 (TPM3) and the depth of tumor invasion, lymph node metastasis, and the 5-year survival rate. However, the specific mechanisms underlying EC remain unclear.

Methods

Stably transfected TPM3-overexpresing and TPM3-knockdown esophageal squamous cell carcinoma (ESCC) cell lines (ECa109 and EC9706) were constructed, and the association between TPM3 and the proliferation, invasion, and migration of ESCC was investigated using molecular biology methods. The associations between TPM3 and matrix metalloproteinase (MMP)2/9 or epithelial-mesenchymal transition (EMT)-related proteins were verified, and the potential tumor-promoting mechanism was explored by Gelatin Zymography Experiment.

Results

TPM3 was found to promote the proliferation, migration, and metastatic potential of ESCC in vivo and in vitro, and stimulate the expression of MMP2/9 and certain EMT markers other than E-cadherin. The replenishment of MMP2/9 restored the malignant behavior of ESCC caused by TPM3. A gelatinase assay showed that the expression of TPM3 was related to the activity of MMP9.

Conclusions

TPM3 promoted proliferation, migration, and metastatic potential in EC cells. Additionally, TPM3 promoted the EMT process. This function may be achieved via the regulation the expression of MMP2/9.

SLUG is upregulated and induces epithelial mesenchymal transition in canine oral squamous cell carcinoma

SLUG, encoded by the Snai2 gene, is known to play a role in epithelial-mesenchymal transition (EMT), which contributes to cell invasion and metastasis in some types of human carcinomas. However, the mechanisms and roles of EMT in canine squamous cell carcinoma (SCC) have not yet been elucidated. We have previously established canine oral SCC cell lines, including tonsillar SCC, and in this study, we evaluated the effects of SLUG on the phenotypes regarding EMT of canine SCC cells. First, immunohistochemical analysis revealed that SLUG is upregulated in canine oral SCC tissues compared to that in non-tumoural oral mucosa. Furthermore, gain-of-function and loss-of-function of SLUG revealed that SLUG partly contributed to migration and invasion of cells, as well as the upregulation of EMT markers such as vimentin and SNAIL. Thus, the current study suggests that SLUG promotes cell migration and invasion through EMT induction in canine oral SCC, as well as human cancers.

SDC1 knockdown induces epithelial-mesenchymal transition and invasion of gallbladder cancer cells via the ERK/Snail pathway

Background

Expression levels of the cell adhesion molecule syndecan-1 (SDC1) have been shown to be inversely proportional to tumor differentiation and prognosis. However, its role in the development of gallbladder cancer (GBC) remains unclear.

Methods

We knocked down SDC1 in GBC cells by RNA interference and determined its roles in cell proliferation, apoptosis, invasion, and migration by Cell Counting Kit-8, colony-formation, flow cytometry, Hoechst 33342 staining, transwell invasion, and scratch wound assays. Expression levels of epithelial–mesenchymal transition (EMT)-related and extracellular signal-regulated kinase (ERK)/Snail pathway proteins were determined by western blotting and immunofluorescence.

Results

Cell proliferation, invasion, and migration were all increased in GBC cells with SDC1 knockdown, compared with cells in the blank control and negative control groups, but apoptosis was similar in all three groups. E-cadherin and β-catenin expression levels were significantly lower and N-cadherin, vimentin, p-ERK1/2, and Snail expression were significantly higher in the SDC1 knockdown group compared with both controls, while ERK1/2 levels were similar in all groups. Reduced E-cadherin and increased vimentin levels were confirmed by immunofluorescence.

Conclusions

SDC1 knockdown promotes the proliferation, invasion, and migration of GBC cells, possibly by regulating ERK/Snail signaling and inducing EMT and cancer cell invasion.

The epithelial-mesenchymal transition regulators Twist, Slug, and Snail are associated with aggressive tumour features and poor outcome in prostate cancer patients

The prognostic importance of transcription factors promoting epithelial-mesenchymal transition (EMT) and angiogenesis has not been well explored in prostate cancer patients with long follow-up, nor the interplay between these factors. The objective of this study was to assess the individual protein expression and co-expression of Twist, Slug (Snai2), Snail (Snai1), and hypoxia-inducible factor-1 alpha (Hif-1α) in prostate cancer in relation to EMT, angiogenesis, hypoxia, tumour features, disease recurrence, and patient survival. Immunohistochemical staining was performed on tissue microarray sections from 338 radical prostatectomies with long follow-up. In addition, 41 cases of prostatic hyperplasia, 33 non-skeletal metastases, 13 skeletal metastases, and 33 castration-resistant prostate carcinomas were included. Our findings were validated in external gene expression data sets. Twist was overexpressed in primary prostate cancer and markedly reduced in distant metastases (p < 0.0005). Strong expression of Twist and Slug was associated with Hif-1α in localised prostate cancer (p ≤ 0.001), and strong Twist was associated with Hif-1α in castration-resistant carcinomas (p = 0.044). Twist, Slug, and increased Snail at the tumour stromal border were associated with vascular factors (p ≤ 0.045). Each of the three EMT-regulating transcription factors were associated with aggressive tumour features and shorter time to recurrence and cancer-specific death. Notably, the co-expression of factors demonstrated an enhanced influence on outcome. In the subgroup of E-cadherinlow carcinomas, strong Slug was associated with shorter time to all end points and was an independent predictor of time to multiple end points, including cancer-specific death (hazard ratio 3.0, p = 0.041). To conclude, we demonstrate an important relation between EMT, hypoxia, and angiogenesis and a strong link between the investigated EMT regulators and aggressive tumour features and poor patient outcome in prostate cancer. Despite the retrospective nature of this long-term study, our findings could have a significant impact on the future treatment of prostate cancer, where tailored therapies might be directed simultaneously against epithelial-mesenchymal phenotypes, angiogenesis, and tumour hypoxia.

Lumican Inhibits In Vivo Melanoma Metastasis by Altering Matrix-Effectors and Invadopodia Markers

It was reported that lumican inhibits the activity of metalloproteinase MMP-14 and melanoma cell migration in vitro and in vivo. Moreover, Snail triggers epithelial-to-mesenchymal transition and the metastatic potential of cancer cells. Therefore, the aim of this study was to examine the effect of lumican on Mock and Snail overexpressing melanoma B16F1 cells in vivo. Lung metastasis was analyzed after intravenous injections of Mock-B16F1 and Snail-B16F1 cells in Lum+/+ and Lum-/- mice. At day 14, mice were sacrificed, and lungs were collected. The number of lung metastatic nodules was significantly higher in mice injected with Snail-B16F1 cells as compared to mice injected with Mock-B16F1 cells confirming the pro-metastatic effect of Snail. This effect was stronger in Lum-/- mice as compared to Lum+/+, suggesting that endogenous lumican of wild-type mice significantly inhibits metastasis to lungs. Scanning electron and confocal microscopy investigations demonstrated that lumican inhibits the development of elongated cancer cell phenotypes which are known to develop invadopodia releasing MMPs. Moreover, lumican was shown to affect the expression of cyclin D1, cortactin, vinculin, hyaluronan synthase 2, heparanase, MMP-14 and the phosphorylation of FAK, AKT, p130 Cas and GSK3α/β. Altogether, these data demonstrated that lumican significantly inhibits lung metastasis in vivo, as well as cell invasion in vitro, suggesting that a lumican-based strategy targeting Snail-induced metastasis could be useful for melanoma treatment.

Aberrant Expression of microRNA Clusters in Head and Neck Cancer Development and Progression: Current and Future Translational Impacts

MicroRNAs are small non-coding RNAs known to negative regulate endogenous genes. Some microRNAs have high sequence conservation and localize as clusters in the genome. Their coordination is regulated by simple genetic and epigenetic events mechanism. In cells, single microRNAs can regulate multiple genes and microRNA clusters contain multiple microRNAs. MicroRNAs can be differentially expressed and act as oncogenic or tumor suppressor microRNAs, which are based on the roles of microRNA-regulated genes. It is vital to understand their effects, regulation, and various biological functions under both normal and disease conditions. Head and neck squamous cell carcinomas are some of the leading causes of cancer-related deaths worldwide and are regulated by many factors, including the dysregulation of microRNAs and their clusters. In disease stages, microRNA clusters can potentially control every field of oncogenic function, including growth, proliferation, apoptosis, migration, and intercellular commutation. Furthermore, microRNA clusters are regulated by genetic mutations or translocations, transcription factors, and epigenetic modifications. Additionally, microRNA clusters harbor the potential to act therapeutically against cancer in the future. Here, we review recent advances in microRNA cluster research, especially relative to head and neck cancers, and discuss their regulation and biological functions under pathological conditions as well as translational applications.

High expression of FABP4 in colorectal cancer and its clinical significance

OBJECTIVES

To investigate the relationship between the fatty acid-binding protein 4 (FABP4) and colorectal cancer (CRC).

METHODS

Using an enzyme-linked immunosorbent assay (ELISA), we measured the expression of FABP4 in plasma of 50 patients who underwent surgery for CRC from October 2017 to May 2018 and 50 healthy controls. The content of the visceral fat area (VFA) as seen with abdominal computed tomography (CT) scanning was measured by ImageJ software. The expression levels of FABP4, E-cadherin, and Snail proteins in CRC and adjacent tissues were determined by immunohistochemistry.

RESULTS

The mean concentration of plasma FABP4 of CRC patients was higher than that of the control group (22.46 vs. 9.82 ng/mL; P<0.05). The concentration of plasma FABP4 was related to the tumor, node, metastatis (TNM) stage and lymph node metastasis and was independent of age, body mass index (BMI), tumor size and location, and the degree of differentiation of CRC. The concentration of plasma FABP4 was positively correlated with high VFA and lipoprotein-a (LPA) (P<0.05); but it was not correlated with total cholesterol (TG), total triglyceride (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), or apolipoprotein AI (Apo-AI). The expression of FABP4 protein in CRC tissues was positively correlated with the degree of CRC differentiation, tumor stage, and lymph node metastasis. The level of FABP4 protein was negatively correlated with E-cadherin protein (r=-0.3292, P=0.0196) and positively correlated with Snail protein (r=0.5856, P<0.0001).

CONCLUSIONS

High LPA and VFA were risk factors for increased plasma FABP4 in CRC patients. FABP4 protein was highly expressed in CRC tissues and associated with TNM stage, differentiation, and lymph node metastasis of CRC. The level of FABP4 in CRC tissue was correlated with E-cadherin and Snail expression, suggesting that FABP4 may promote CRC progression related to epithelial-mesenchymal transition (EMT).

EZH2 and KDM6B Expressions Are Associated with Specific Epigenetic Signatures during EMT in Non Small Cell Lung Carcinomas

The role of Epigenetics in Epithelial Mesenchymal Transition (EMT) has recently emerged. Two epigenetic enzymes with paradoxical roles have previously been associated to EMT, EZH2 (Enhancer of Zeste 2 Polycomb Repressive Complex 2 (PRC2) Subunit), a lysine methyltranserase able to add the H3K27me3 mark, and the histone demethylase KDM6B (Lysine Demethylase 6B), which can remove the H3K27me3 mark. Nevertheless, it still remains unclear how these enzymes, with apparent opposite activities, could both promote EMT. In this study, we evaluated the function of these two enzymes using an EMT-inducible model, the lung cancer A549 cell line. ChIP-seq coupled with transcriptomic analysis showed that EZH2 and KDM6B were able to target and modulate the expression of different genes during EMT. Based on this analysis, we described INHBB, WTN5B, and ADAMTS6 as new EMT markers regulated by epigenetic modifications and directly implicated in EMT induction.

Overexpression of DDR1 Promotes Migration, Invasion, Though EMT-Related Molecule Expression and COL4A1/DDR1/MMP-2 Signaling Axis

Purpose:

Discoidin domain receptor 1 (DDR1) belongs to a novel class of receptor tyrosine kinases. Previous evidence indicates that DDR1 overexpression promotes the aggressive growth of bladder cancer (BC) cells. This study aimed to investigate the molecular mechanisms by which DDR1 influences BC.

Methods:

DDR1 was transfected into human BC RT4 cells. DDR1, COL4A1, and MMP-2 expression in 30 BC tissues and paired adjacent tissues were examined by real-time polymerase chain reaction (RT-PCR) and immunohistochemistry. Transwell assays were conducted to determine cell migration and invasion. RT-PCR and western blot (WB) were also used to measure the DDR1, COL4A1, MMP-2, and EMT-related gene (ZEB1 and SLUG) expression in RT4 cells after DDR1 overexpression.

Results:

COL4A1 and MMP-2 interacted with DDR1 in the PPI network. RT-PCR and immunohistochemistry results showed that both mRNA and protein levels of DDR1 and COL4A1 were significantly increased in BC tissue, while the expression of MMP-2 was increased only at the mRNA level (P < 0.05). Overexpression of DDR1 in RT4 cells significantly promoted their migratory and invasive capabilities in vitro (P < 0.05). Moreover, overexpression of DDR1 in RT4 cells increased the mRNA and protein expression of ZEB1, SLUG, COL4A1, and MMP-2 (P < 0.01). DDR1-mediated migration and invasion of RT4 cells were reversed after COL4A1-siRNA treatment.

Conclusion:

DDR1 may be a potential therapeutic target in BC patients.

Signaling pathways promoting epithelial mesenchymal transition in oral submucous fibrosis and oral squamous cell carcinoma

Epithelial-mesenchymal transition (EMT) is a critical process that occurs during the embryonic development, wound healing, organ fibrosis and the onset of malignancy. Emerging evidence suggests that the EMT is involved in the invasion and metastasis of cancers. The inflammatory reaction antecedent to fibrosis in the onset of oral submucous fibrosis (OSF) and the role of EMT in its malignant transformation indicates a hitherto unexplored involvement of EMT. This review focuses on the role of EMT markers which are regulators of the EMT mediated complex network of molecular mechanisms involved in the pathogenesis of OSF and OSCC. Further the gene enrichment analysis and pathway analysis supports the association of the upregulated and downregulated genes in various EMT regulating pathways.

Biological role of epithelial-mesenchymal-transition-inducing transcription factors in head and neck squamous cell carcinoma: A systematic review

OBJECTIVE

The aim of this systematic review was to explore the biological functions and mechanisms of epithelial-mesenchymal transition-inducing transcription factors in head and neck squamous cell carcinoma-derived cell lines. In addition, we analyzed the possible usefulness of epithelial-mesenchymal transition-inducing transcription factors as a future therapeutic target.

DESIGN

An electronic search was performed in EMBASE, Medline/PubMed, Chinese BioMedical Literature Databases, and Cochrane Collaboration Library. Articles evaluating the relationship between epithelial-mesenchymal transition-inducing transcription factors and the biological behavior of head and neck squamous cell carcinoma cell lines were selected for this systematic review. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

After application of the previously established inclusion/exclusion criteria, 23 articles were included in the qualitative synthesis. Our study showed that epithelial-mesenchymal transition-inducing transcription factors are essential components during the progression of head and neck squamous cell carcinomas and their overexpression is associated with a greater capacity of dissemination and survival of the tumor and resistance to cancer treatment. The inhibition of epithelial-mesenchymal transition-inducing transcription factors is able to reverse the epithelial-mesenchymal transition process and to increase the sensitivity of head and neck squamous cell carcinoma cell lines to radio/chemotherapy.

CONCLUSIONS

Analysis of the expression of epithelial-mesenchymal transition-inducing transcription factors for the prediction of prognosis and response to cancer treatment may have a significant clinical impact.

MicroRNA-33b Suppresses Epithelial-Mesenchymal Transition Repressing the MYC-EZH2 Pathway in HER2+ Breast Carcinoma

Downregulation of miR-33b has been documented in many types of cancers and is being involved in proliferation, migration, and epithelial–mesenchymal transition (EMT). Furthermore, the enhancer of zeste homolog 2-gene (EZH2) is a master regulator of controlling the stem cell differentiation and the cell proliferation processes. We aim to evaluate the implication of miR-33b in the EMT pathway in HER2+ breast cancer (BC) and to analyze the role of EZH2 in this process as well as the interaction between them. miR-33b is downregulated in HER2+ BC cells vs healthy controls, where EZH2 has an opposite expression in vitro and in patients’ samples. The upregulation of miR-33b suppressed proliferation, induced apoptosis, reduced invasion, migration and regulated EMT by an increase of E-cadherin and a decrease of ß-catenin and vimentin. The silencing of EZH2 mimicked the impact of miR-33b overexpression. Furthermore, the inhibition of miR-33b induces cell proliferation, invasion, migration, EMT, and EZH2 expression in non-tumorigenic cells. Importantly, the Kaplan–Meier analysis showed a significant association between high miR-33b expression and better overall survival. These results suggest miR-33b as a suppressive miRNA that could inhibit tumor metastasis and invasion in HER2+ BC partly by impeding EMT through the repression of the MYC–EZH2 loop.

The roles of microRNAs in the stemness of oral cancer cells

Oral cancer (OC), which is the most common form of head and neck cancers, has one of the lowest (~50%) overall 5-year survival rates. The main reasons for this high mortality rate are diagnosis of OC in advanced stages in most patients and spread to distant organs via lymph node metastasis. Many studies have shown that a small population of cells within the tumor plays vital roles in the initiation, progression, and metastasis of the tumor, resistance to chemotherapeutic agents, and recurrence. These cells, identified as cancer stem cells (CSCs), are the main reasons for the failure of current treatment modalities. Deregulated expressions of microRNAs are closely related to tumor prognosis, metastasis and drug resistance. In addition, microRNAs play important roles in regulating the functions of CSCs. Until now, the roles of microRNAs in the acquisition and maintenance of OC stemness have not been elucidated in detail yet. Here in this review, we summarized significant findings and the latest literature to better understand the involvement of CSCs in association with dysregulated microRNAs in oral carcinogenesis. Possible roles of these microRNAs in acquisition and maintenance of CSCs features during OC pathogenesis were summarized.

The New Model of Snail Expression Regulation: The Role of MRTFs in Fast and Slow Endothelial-Mesenchymal Transition

Endothelial–mesenchymal transition (EndMT) is a crucial phenomenon in regulating the development of diseases, including cancer metastasis and fibrotic disorders. The primary regulators of disease development are zinc-finger transcription factors belonging to the Snail family. In this study, we characterized the myocardin-related transcription factor (MRTF)-dependent mechanisms of a human snail promoter regulation in TGF-β-stimulated human endothelial cells. Although in silico analysis revealed that the snail promoter’s regulatory fragment contains one GCCG and two SP1 motifs that could be occupied by MRTFs, the genetic study confirmed that MRTF binds only to SP1 sites to promote snail expression. The more accurate studies revealed that MRTF-A binds to both SP1 elements, whereas MRTF-B to only one (SP1near). Although we found that each MRTF alone is capable of inducing snail expression, the direct cooperation of these proteins is required to reinforce snail expression and promote the late stages of EndMT within 48 hours. Furthermore, genetic and biochemical analysis revealed that MRTF-B alone could induce the late stage of EndMT. However, it requires a prolonged time. Therefore, we concluded that MRTFs might cause EndMT in a fast- and slow-dependent manner. Based on MRTF-dependent Snail upregulation, we recognized that TGF-β1, as an MRTF-B regulator, is involved in slow EndMT induction, whereas TGF-β2, which altered both MRTF-A and MRTF-B expression, promotes a fast EndMT process.

SUMOylation of E2F1 Regulates Expression of EZH2

Elevated expression of EZH2, the enzymatic subunit of polycomb repressive complex 2 (PRC2), often occurs in cancer. EZH2 expression results in the silencing of genes that suppress tumor formation and metastasis through trimethylation of histone H3 at lysine 27 (H3K27me3) at their promoters. However, inhibitors of EZH2 enzymatic activity have not shown the expected efficacy against cancer in clinical trials, suggesting a need for other strategies to address EZH2 overexpression. Here, we show that SUMOylation, a posttranslational modification characterized by covalent attachment of small ubiquitin-like modifier (SUMO) proteins to a lysine (Lys) residue on target proteins, enhances EZH2 transcription. Either knockdown of the SUMO-activating enzyme SAE2 or pharmacologic inhibition of SUMOylation resulted in decreased levels of EZH2 mRNA and protein as well as reduced H3K27me3 levels. SUMOylation regulated EZH2 expression by enhancing binding of the E2F1 transcriptional activator to the EZH2 promoter. Inhibition of SUMOylation not only resulted in reduced EZH2 mRNA and protein levels but also increased expression of genes silenced by EZH2, such as E-cadherin, which suppresses epithelial-mesenchymal transition and metastasis. In more than 6,500 patient tumor samples across different cancer types, expression of UBA2 and EZH2 was positively correlated. Taken together, our findings suggest that inhibition of SUMOylation may serve as a potential strategy to address EZH2 overexpression and improve current cancer therapeutic approaches. SIGNIFICANCE: These findings provide important biological insights into the mechanism of EZH2 overexpression in cancers and suggest that inhibiting SUMOylation may improve current cancer therapeutic approaches.

Slug is a novel molecular target for head and neck squamous cell carcinoma stem-like cells

BACKGROUND

The acquisition of stem-like phenotype is partly attributed to the induction of epithelial-mesenchymal transition (EMT). Thus, the activation of factors involved in EMT can be linked to cancer stem cell genesis. However, the underlying mechanisms in head and neck squamous cell carcinoma (HNSCC) remain largely unknown. Herein, we investigate whether slug, one of the major effectors of EMT, affects the stemness of HNSCC cells.

METHODS

We performed in vitro experiments to determine whether slug gene manipulation can influence the stemness phenotypes, including the capacity for self-renewal, expression of putative stemness markers, chemoresistance, and invasion in HNSCC cells. Further, we identified whether Slug knockout attenuates tumorigenicity of HNSCC cells in vivo. Finally, we examined whether prognosis of HNSCC patients after curative treatment may be affected by the level of slug expression.

RESULTS

Overexpression of slug promoted self-renewal of HNSCC cells via activation of sphere formation, the expression of stem cell markers, and induction of chemoresistance to cisplatin. Also, slug overexpression increased the migration and invasion of HNSCC cells in vitro and was mainly observed during the invasion in HNSCC xenograft mouse model. By contrast, slug expression knockdown abrogated their self-renewal capacity, stemness-associated gene expression, and cisplatin chemoresistance. Furthermore, high levels of slug expression correlated with poor prognosis of patients with HNSCC.

CONCLUSION

Inhibition of slug expression may represent a novel therapeutic strategy targeting HNSCC stem-like cells.

Docosahexaenoic acid (DHA) inhibits pro-angiogenic effects of breast cancer cells via down-regulating cellular and exosomal expression of angiogenic genes and microRNAs

AIMS

Docosahexaenoic acid (DHA) as an omega 3 free fatty acid has been reported to exert anti-angiogenesis effects. However, our current understanding regarding the precise mechanisms of such effects is still limited. Exosomes secreted by cancer cells may act as angiogenesis promoters. The aim of the study was to determine altered expression levels of HIF-1α, TGF-β, VEGFR, Snail1, Snail2 and SOX2 and their regulating microRNAs in MDA-MB-231 and BT-474 cell lines after treatment with DHA in both normoxic and hypoxic conditions.

MAIN METHODS

Human breast cancer cell lines including MDA-MB-231 and BT-474 were treated for 24 h with 100 uM DHA under normoxic and hypoxic conditions. Exosomes were isolated from untreated and treated cells and characterized by transmission electron microscopy (TEM) and western blotting. RNAs from cells and isolated exosomes were extracted and cDNAs were synthesized. Expression levels of miRNAs and their pro-angiogenic target genes were analyzed using quantitative real-time PCR (qRT-PCR).

KEY FINDINGS

We showed significant decrease in the expression of pro-angiogenic genes including HIF1-α, TGF-β, SOX2, Snail1, Snail2 and VEGFR in cells and also their secreted exosomes after treatment with DHA in normoxic and hypoxic conditions. Also the expression levels of tumor suppressor miRs including miR-101, miR-199, miR-342 were increased and the expression levels of oncomiRs including mir-382 and miR-21 were decreased after treatment with DHA in cells and exosomes.

SIGNIFICANCE

DHA can alter the expression of pro-angiogenic genes and microRNA contents in breast cancer cells and their derived-exosomes in favor of the inhibition of angiogenesis. Our data demonstrated new insight into DHA's anti-cancer action to target not only breast cancer cells but also their derived exosomes to suppress tumor angiogenesis.

Role of microRNA-33a in malignant cells

Cancer causes most of the mortality and morbidity worldwide, with a significant increase in incidence during recent years. MicroRNAs (miRNAs/miRs) are non-coding small RNAs capable of regulating gene expression. They regulate crucial cellular processes, including proliferation, differentiation, metastasis and apoptosis. Therefore, abnormal miRNA expression is associated with multiple diseases, including cancer. There are two types of cancer-associated miRNAs, oncogenic and tumor suppressor miRNAs, depending on their roles and expression patterns in cancer. Accordingly, miRNAs are considered to be targets for cancer prevention and treatment. miR-33a controls cellular cholesterol uptake and synthesis, which are both closely associated with carcinogenesis. The present review thoroughly describes the roles of miR-33a in more than a dozen types of cancer and the underlying mechanisms. Accordingly, the present review may serve as a guide for researchers studying the involvement of miR-33a in diverse cancer settings.

Insight toward the MicroRNA Profiling of Laryngeal Cancers: Biological Role and Clinical Impact

Head and neck squamous cell carcinoma (HNSCC), a heterogeneous disease arising from various anatomical locations including the larynx, is a leading cause of death worldwide. Despite advances in multimodality treatment, the overall survival rate of the disease is still largely dismal. Early and accurate diagnosis of HNSCC is urgently demanded in order to prevent cancer progression and to improve the quality of the patient's life. Recently, microRNAs (miRNAs), a family of small non-coding RNAs, have been widely reported as new robust tools for prediction, diagnosis, prognosis, and therapeutic approaches of human diseases. Abnormally expressed miRNAs are strongly associated with cancer development, resistance to chemo-/radiotherapy, and metastatic potential through targeting a large variety of genes. In this review, we summarize on the recent reports that emphasize the pivotal biological roles of miRNAs in regulating carcinogenesis of HNSCC, particularly laryngeal cancer. In more detail, we report the characterized miRNAs with an evident either oncogenic or tumor suppressive role in the cancers. In addition, we also focus on the correlation between miRNA deregulation and clinical relevance in cancer patients. On the basis of intriguing findings, the study of miRNAs will provide a new great opportunity to access better clinical management of the malignancies.

Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 cooperates with enhancer of zeste homolog 2 to promote hepatocellular carcinoma development by modulating the microRNA-22/Snail family transcriptional repressor 1 axis

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is an oncogenic long noncoding RNA that has been found to promote carcinogenesis and metastasis in many tumors. However, the underlying role of MALAT1 in the progression and metastasis of hepatocellular carcinoma (HCC) remains unclear. In this study, aberrantly elevated levels of MALAT1 were detected in both HCC specimens and cell lines. We found that knockdown of MALAT1 caused retardation in proliferation, migration, and invasion both in vivo and in vitro. Mechanistic investigations showed that Snail family transcriptional repressor 1 (SNAI1) is a direct target of microRNA (miR)-22 and that MALAT1 modulates SNAI1 expression by acting as a competing endogenous RNA for miR-22. Inhibition of miR-22 restored SNAI1 expression suppressed by MALAT1 knockdown. Furthermore, MALAT1 facilitated the enrichment of enhancer of zeste homolog 2 (EZH2) at the promoter region of miR-22 and E-cadherin, which was repressed by MALAT1 knockdown. Cooperating with EZH2, MALAT1 positively regulated SNAI1 by repressing miR-22 and inhibiting E-cadherin expression, playing a vital role in epithelial to mesenchymal transition. In conclusion, our results reveal a mechanism by which MALAT1 promotes HCC progression and provides a potential target for HCC therapy.

miR-101-3p and miR-199b-5p promote cell apoptosis in oral cancer by targeting BICC1

microRNAs (miRNAs) are involved in the carcinogenesis and progression of oral cancer. In this research, we aimed to identify the DE_miRNAs in oral cancer and the related molecular mechanisms. Using the GEO2R online tool, we identified 19 DE_miRNAs from the GSE115117 dataset and 3343 the DEGs from GSE74530 dataset. GO enrichment analysis of DE_miRNAs were performed using FunRich online analysis. Venn diagrams of the overlapping genes regulated by miR-204-5p, miR-199b-5p, and miR-101-3p were constructed using Draw Venn Diagram, FunRich, miRDB, TargetScan and GSE74530 databases. Cytoscape was used to construct a miRNAs-mRNAs network. RT-PCR and western blotting showed downregulation of miR-199b-5p and miR-101-3p, and upregulation of BICC1 in oral cancer cell lines and tissues. Spearman correlation analysis further demonstrated a positive correlation between miR-101-3p and miR-199b-5p levels and that miR-199b-5p and miR-101-3p were negatively correlated with BICC1 mRNA levels. miR-199b-5p and BICC1 were significantly related to survival rate of patients with oral cancer. Upregulation of miR-199b-5p and miR-101-3p inhibited the viability and promoted the apoptosis in TSCCA and SCC-9 cells, as shown by the CCK8 assay and flow cytometry analysis, respectively. Inhibition of BICC1 reduced viability and promoted apoptosis in TSCCA cells. Additionally, the relationship between BICC1 and both miR-101-3p and miR-199b-5p was assessed by a luciferase reporter assay. The effects of miR-101-3p and miR-199b-5p upregulation on the promotion of cell apoptosis and the inhibition of tumor growth were reversed by overexpression of BICC1. In conclusion, the increased levels of miR-199b-5p and miR-101-3p enhanced apoptosis and suppressed cell viability in oral cancer by suppressing BICC1 expression.

Prognostic value of the immunohistochemical detection of epithelial-mesenchymal transition biomarkers in oral epithelial dysplasia: A systematic review

BACKGROUND

Oral potentially malignant disorders (OPMDs) comprise a range of clinical-pathological alterations that are frequently characterized as architectural and cytological derangements upon histological analysis. Epithelial-mesenchymal transition (EMT) has been proposed as a critical mechanism for the acquisition of the malignant phenotype in neoplastic epithelial processes. This study aims to systematically review the current findings on the immunohistochemical expression of epithelial-mesenchymal transition markers in oral potentially malignant disorders and to evaluate their possible application as biomarkers associated with the progression of oral epithelial dysplasias.

MATERIAL AND METHODS

A systematic search was performed in the following databases: PubMed, EMBASE, Chinese BioMedical Literature Database, and Cochrane Library. Articles that evaluated the relationship between the expression of EMT markers and the degree of oral epithelial dysplasia were selected for the systematic review. The quality of each eligible study was evaluated by independent reviewers that used operationalized prognostic biomarker reporting guidelines (REMARK).

RESULTS

Seventeen articles met all inclusion criteria and were selected. The EMT markers analyzed exhibited an important association with the prognosis of the cases evaluated. The results showed a progressive increase in the expression of nuclear transcription factors and markers of mesenchymal differentiation, as well as negative regulation of epithelial and cell adhesion markers, according to the stage of oral epithelial dysplasia.

CONCLUSIONS

The dysregulation of expression of important EMT components in oral dysplastic epithelium is a potential prognostic marker in OPMDs.

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.

Enhanced and Prolonged Antitumor Effect of Salinomycin-Loaded Gelatinase-Responsive Nanoparticles via Targeted Drug Delivery and Inhibition of Cervical Cancer Stem Cells

BACKGROUND

Cervical cancer stem cells (CCSCs) represent a subpopulation of tumor cells that possess self-renewal capacity and numerous intrinsic mechanisms of resistance to conventional chemotherapy and radiotherapy. These cells play a crucial role in relapse and metastasis of cervical cancer. Therefore, eradication of CCSCs is the primary objective in cervical cancer therapy. Salinomycin (Sal) is an agent used for the elimination of cancer stem cells (CSCs); however, the occurrence of several side effects hinders its application. Nanoscale drug-delivery systems offer great promise for the diagnosis and treatment of tumors. These systems can be used to reduce the side effects of Sal and improve clinical benefit.

METHODS

Sal-loaded polyethylene glycol-peptide-polycaprolactone nanoparticles (Sal NPs) were fabricated under mild and non-toxic conditions. The real-time biodistribution of Sal NPs was investigated through non-invasive near-infrared fluorescent imaging. The efficacy of tumor growth inhibition by Sal NPs was evaluated using tumor xenografts in nude mice. Flow cytometry, immunohistochemistry, and Western blotting were used to detect the apoptosis of CSCs after treatment with Sal NPs. Immunohistochemistry and Western blotting were used to examine epithelial-mesenchymal transition (epithelial interstitial transformation) signal-related molecules.

RESULTS

Sal NPs exhibited antitumor efficacy against cervical cancers by inducing apoptosis of CCSCs and inhibiting the epithelial-mesenchymal transition pathway. Besides, tumor pieces resected from Sal NP-treated mice showed decreased reseeding ability and growth speed, further demonstrating the significant inhibitory ability of Sal NPs against CSCs. Moreover, owing to targeted delivery based on the gelatinase-responsive strategy, Sal NPs was more effective and tolerable than free Sal.

CONCLUSION

To the best of our knowledge, this is the first study to show that CCSC-targeted Sal NPs provide a potential approach to selectively target and efficiently eradicate CCSCs. This renders them a promising strategy to improve the therapeutic effect against cervical cancer.

Prognostic value of epithelial-mesenchymal transition-inducing transcription factors in head and neck squamous cell carcinoma: A meta-analysis

Epithelial-mesenchymal transition (EMT) plays a critical role in cancer progression and is primarily regulated by several EMT-inducing transcription factors (EMT-TFs), including TWIST1, TWIST2, SNAI1, SNAI2, ZEB1, and ZEB2. However, the prognostic value of EMT-TFs remains controversial in head and neck squamous cell carcinoma (HNSCC). Studies on the prognostic role of EMT-TFs in HNSCC were searched for in the Web of Science, Science Direct, Proquest, EMBASE, PubMed, and Cochrane Library. Meta-analysis was performed by using Revman 5.2 software. The pooled analysis showed that overexpression of EMT-TFs indicated a poor overall survival (OS) (HR = 1.93, 95% CI = 1.67-2.23) of HNSCC. Subgroup analysis for individual EMT-TFs revealed that overexpression of TWIST1 (HR = 1.61, 95% CI = 1.29-2.02), SNAI1 (HR = 2.17, 95% CI = 1.63-2.88), SNAI2 (HR = 1.90, 95% CI = 1.38-2.62), and ZEB1 (HR = 2.70, 95% CI = 1.61-4.53) were significantly associated with poor OS of HNSCC. These findings support the hypothesis that overexpression of EMT-TFs indicates a poor prognosis for HNSCC patients.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

G-protein-coupled receptor kinase 2 safeguards epithelial phenotype in head and neck squamous cell carcinomas

Head and neck squamous cell carcinoma (HNSCC) arises from the mucosal lining of the upper aerodigestive tract and display few treatment options in advanced stages. Despite increased knowledge of HNSCC molecular biology, the identification of new players involved in triggering HNSCC recurrence and metastatic disease is needed. We uncover that G-protein-coupled receptor kinase-2 (GRK2) expression is reduced in undifferentiated, high-grade human HNSCC tumors, whereas its silencing in model human HNSCC cells is sufficient to trigger epithelial-to-mesenchymal transition (EMT) phenotypic features, an EMT-like transcriptional program and enhanced lymph node colonization from orthotopic tongue tumors in mice. Conversely, enhancing GRK2 expression counteracts mesenchymal cells traits by mechanisms involving phosphorylation and decreased functionality of the key EMT inducer Snail1. Our results suggest that GRK2 safeguards the epithelial phenotype, whereas its downregulation contributes to the activation of EMT programs in HNSCC.

EZH2 promotes invasion and tumour glycolysis by regulating STAT3 and FoxO1 signalling in human OSCC cells

The enhancer of zeste homolog 2 (EZH2), known as a member of the polycomb group (PcG) proteins, is an oncogene overexpressed in a variety of human cancers. Here, we found that EZH2 correlated with poor survival of oral squamous cell carcinoma (OSCC) patients using immunohistochemistry staining. EZH2 overexpression led to a significant induction in tumour glycolysis, Epithelial‐mesenchymal transition (EMT), migration and invasion of OSCC cells. Conversely, silencing of EZH2 inhibited tumour glycolysis, EMT, migration and invasion in OSCC cells. Ectopic overexpression of EZH2 increased phosphorylation of STAT3 at pY705 and decreased FoxO1 expression, and FoxO1 expression was enhanced when inhibiting STAT3. In addition, EZH2 overexpression led to a significant decrease in FoxO1 mRNA levels in nude mice xenograft. These results indicated that regulation of EZH2 might have the potential to be targeted for OSCC treatment.