Functional Role of Non-Coding RNAs during Epithelial-To-Mesenchymal Transition

Exploring the role non-coding RNAs during myocardial cell fate

Myocardial cell fate specification takes place during the early stages of heart development as the precardiac mesoderm is configured into two symmetrical sets of bilateral precursor cells. Molecular cues of the surrounding tissues specify and subsequently determine the early cardiomyocytes, that finally matured as the heart is completed at early postnatal stages. Over the last decade, we have greatly enhanced our understanding of the transcriptional regulation of cardiac development and thus of myocardial cell fate. The recent discovery of a novel layer of gene regulation by non-coding RNAs has flourished their implication in epigenetic, transcriptional and post-transcriptional regulation of cardiac development. In this review, we revised the current state-of-the-art knowledge on the functional role of non-coding RNAs during myocardial cell fate.

Novel Insights into the Molecular Mechanisms Governing Embryonic Epicardium Formation

The embryonic epicardium originates from the proepicardium, an extracardiac primordium constituted by a cluster of mesothelial cells. In early embryos, the embryonic epicardium is characterized by a squamous cell epithelium resting on the myocardium surface. Subsequently, it invades the subepicardial space and thereafter the embryonic myocardium by means of an epithelial-mesenchymal transition. Within the myocardium, epicardial-derived cells present multilineage potential, later differentiating into smooth muscle cells and contributing both to coronary vasculature and cardiac fibroblasts in the mature heart. Over the last decades, we have progressively increased our understanding of those cellular and molecular mechanisms driving proepicardial/embryonic epicardium formation. This study provides a state-of-the-art review of the transcriptional and emerging post-transcriptional mechanisms involved in the formation and differentiation of the embryonic epicardium.

The lncRNA RMST is drastically downregulated in anaplastic thyroid carcinomas where exerts a tumor suppressor activity impairing epithelial-mesenchymal transition and stemness

Thyroid cancer is the most prevalent endocrine malignancy and comprises a wide range of lesions subdivided into differentiated (DTC) and undifferentiated thyroid cancer (UTC), mainly represented by the anaplastic thyroid carcinoma (ATC). This is one of the most lethal malignancies in humankind leading invariably to patient death in few months. Then, a better comprehension of the mechanisms underlying the development of ATC is required to set up new therapeutic approaches. Long non-coding RNAs (lncRNAs) are transcripts over 200 nucleotides in length that do not code for proteins. They show a strong regulatory function at both transcriptional and post-transcriptional level and are emerging as key players in regulating developmental processes. Their aberrant expression has been linked to several biological processes, including cancer, making them potential diagnostic and prognostic markers. We have recently analyzed the lncRNA expression profile in ATC through a microarray technique and have identified rhabdomyosarcoma 2-associated transcript (RMST) as one of the most downregulated lncRNA in ATC. RMST has been reported to be deregulated in a series of human cancers, to play an anti-oncogenic role in triple-negative breast cancer, and to modulate neurogenesis by interacting with SOX2. Therefore, these findings prompted us to investigate the role of RMST in ATC development. In this study we show that RMST levels are strongly decreased in ATC, but only slightly in DTC, indicating that the loss of this lncRNA could be related to the loss of the differentiation and high aggressiveness. We also report a concomitant increase of SOX2 levels in the same subset of ATC, that inversely correlated with RMST levels, further supporting the RMST/SOX2 relationship. Finally, functional studies demonstrate that the restoration of RMST in ATC cells reduces cell growth, migration and the stemness properties of ATC stem cells. In conclusion, these findings support a critical role of RMST downregulation in ATC development.

Zeb2 DNA-Binding Sites in Neuroprogenitor Cells Reveal Autoregulation and Affirm Neurodevelopmental Defects, Including in Mowat-Wilson Syndrome

Functional perturbation and action mechanism studies have shown that the transcription factor Zeb2 controls cell fate decisions, differentiation, and/or maturation in multiple cell lineages in embryos and after birth. In cultured embryonic stem cells (ESCs), Zeb2’s mRNA/protein upregulation is necessary for the exit from primed pluripotency and for entering general and neural differentiation. We edited mouse ESCs to produce Flag-V5 epitope-tagged Zeb2 protein from one endogenous allele. Using chromatin immunoprecipitation coupled with sequencing (ChIP-seq), we mapped 2432 DNA-binding sites for this tagged Zeb2 in ESC-derived neuroprogenitor cells (NPCs). A new, major binding site maps promoter-proximal to Zeb2 itself. The homozygous deletion of this site demonstrates that autoregulation of Zeb2 is necessary to elicit the appropriate Zeb2-dependent effects in ESC-to-NPC differentiation. We have also cross-referenced all the mapped Zeb2 binding sites with previously obtained transcriptome data from Zeb2 perturbations in ESC-derived NPCs, GABAergic interneurons from the ventral forebrain of mouse embryos, and stem/progenitor cells from the post-natal ventricular-subventricular zone (V-SVZ) in mouse forebrain, respectively. Despite the different characteristics of each of these neurogenic systems, we found interesting target gene overlaps. In addition, our study also contributes to explaining developmental disorders, including Mowat-Wilson syndrome caused by ZEB2 deficiency, and also other monogenic syndromes.

Diabetic nephropathy: Focusing on pathological signals, clinical treatment, and dietary regulation

Diabetic nephropathy (DN) is one of the most severe complications of diabetes. However, due to its complex pathological mechanisms, no effective therapeutic methods (other than ACEIs and ARBs) have been applied, which have been used for many years in clinical practice. Recent studies have shown that emerging therapeutics, including novel target-based pharmacotherapy, cell therapies, and dietary regulation, are leading to new hopes for DN management. This review aims to shed new light on the treatment of DN by describing the important pathological mechanisms of DN and by analysing recent advances in clinical treatment, including drug therapy, cell therapy, and dietary regulation. In pathological mechanisms, RAAS activation, AGE accumulation, and EMT are involved in inflammation, cellular stress, apoptosis, pyroptosis, and autophagy. In pharmacotherapy, several new therapeutics, including SGLT2 inhibitors, GLP-1 agonists, and MRAs, are receiving public attention. In addition, stem cell therapies and dietary regulation are also being emphasized. Herein, we highlight the importance of combining therapy and dietary regulation in the treatment of DN and anticipate more basic research or clinical trials to verify novel strategies.

TGFβ1-Induced EMT in the MCF10A Mammary Epithelial Cell Line Model Is Executed Independently of SNAIL1 and ZEB1 but Relies on JUNB-Coordinated Transcriptional Regulation

Epithelial-mesenchymal transition (EMT) fosters cancer cell invasion and metastasis, the main cause of cancer-related mortality. Growing evidence that SNAIL and ZEB transcription factors, typically portrayed as master regulators of EMT, may be dispensable for this process, led us to re-investigate its mechanistic underpinnings. For this, we used an unbiased computational approach that integrated time-resolved analyses of chromatin structure and differential gene expression, to predict transcriptional regulators of TGFβ1-inducible EMT in the MCF10A mammary epithelial cell line model. Bioinformatic analyses indicated comparatively minor contributions of SNAIL proteins and ZEB1 to TGFβ1-induced EMT, whereas the AP-1 subunit JUNB was anticipated to have a much larger impact. CRISPR/Cas9-mediated loss-of-function studies confirmed that TGFβ1-induced EMT proceeded independently of SNAIL proteins and ZEB1. In contrast, JUNB was necessary and sufficient for EMT in MCF10A cells, but not in A549 lung cancer cells, indicating cell-type-specificity of JUNB EMT-regulatory capacity. Nonetheless, the JUNB-dependence of EMT-associated transcriptional reprogramming in MCF10A cells allowed to define a gene expression signature which was regulated by TGFβ1 in diverse cellular backgrounds, showed positively correlated expression with TGFβ signaling in multiple cancer transcriptomes, and was predictive of patient survival in several cancer types. Altogether, our findings provide novel mechanistic insights into the context-dependent control of TGFβ1-driven EMT and thereby may lead to improved diagnostic and therapeutic options.

Comparative Analysis of Non-Coding RNA Transcriptomics in Heart Failure

Heart failure constitutes a clinical complex syndrome with different symptomatic characteristics depending on age, sex, race and ethnicity, among others, which has become a major public health issue with an increasing prevalence. One of the most interesting tools seeking to improve prevention, diagnosis, treatment and prognosis of this pathology has focused on finding new molecular biomarkers since heart failure relies on deficient cardiac homeostasis, which is regulated by a strict gene expression. Therefore, currently, analyses of non-coding RNA transcriptomics have been oriented towards human samples. The present review develops a comparative study emphasizing the relevance of microRNAs, long non-coding RNAs and circular RNAs as potential biomarkers in heart failure. Significantly, further studies in this field of research are fundamental to supporting their widespread clinical use. In this sense, the various methodologies used by the authors should be standardized, including larger cohorts, homogeneity of the samples and uniformity of the bioinformatic pipelines used to reach stratification and statistical significance of the results. These basic adjustments could provide promising steps to designing novel strategies for clinical management of patients with heart failure.

Cordycepin Inhibits Growth and Metastasis Formation of MDA-MB-231 Xenografts in Nude Mice by Modulating the Hedgehog Pathway

We previously found that cordycepin inhibits the growth and metastasis formation of MDA-MB-231 cells through the Hedgehog pathway but has not validated this in vivo. In this study, we confirmed cordycepin’s anti-triple-negative breast cancer (TNBC) effect in nude mice and documented its mechanism. We found that cordycepin reduced the volume and weight of MDA-MB-231 xenografts and affected the expression of proliferation-, apoptosis-, epithelial–mesenchymal transition-, and matrix metalloproteinase-related proteins without side effects. RNA sequencing screening, pathway enrichment, and the protein network interaction analysis revealed enriched pathways and targets mainly concentrated on the Hedgehog pathway and its core components of SHH and GLI2. This indicates that the Hedgehog pathway plays a central role in the cordycepin-mediated regulation of growth and metastasis formation in TNBC. The database analysis of the Hedgehog pathway markers (SHH, PTCH1, SMO, GLI1, and GLI2) revealed that the Hedgehog pathway is activated in breast cancer tissues, and its high expression is not conducive to a patient’s survival. Finally, we verified that cordycepin effectively inhibited the Hedgehog pathway in TNBC through Western blotting and immunohistochemistry. This study found that cordycepin could regulate the growth and metastasis formation of TNBC through the Hedgehog pathway in vivo, which provides new insights for targeting and treating breast cancer.

LncRNA H19 Impairs Chemo and Radiotherapy in Tumorigenesis

Various treatments based on drug administration and radiotherapy have been devoted to preventing, palliating, and defeating cancer, showing high efficiency against the progression of this disease. Recently, in this process, malignant cells have been found which are capable of triggering specific molecular mechanisms against current treatments, with negative consequences in the prognosis of the disease. It is therefore fundamental to understand the underlying mechanisms, including the genes—and their signaling pathway regulators—involved in the process, in order to fight tumor cells. Long non-coding RNAs, H19 in particular, have been revealed as powerful protective factors in various types of cancer. However, they have also evidenced their oncogenic role in multiple carcinomas, enhancing tumor cell proliferation, migration, and invasion. In this review, we analyze the role of lncRNA H19 impairing chemo and radiotherapy in tumorigenesis, including breast cancer, lung adenocarcinoma, glioma, and colorectal carcinoma.

Long non-coding RNA RGMB-AS1 represses nasopharyngeal carcinoma progression via binding to forkhead box A1

Long non-coding RNA RGMB-AS1 (RGMB antisense RNA 1) plays a crucial role in tumor progression. However, its underlying mechanism in nasopharyngeal carcinoma (NPC) remains unclear. In this study, we analyzed the clinical significance of lncRNA RGMB-AS1 as a possible potential marker in NPC, and investigated the effect and mechanism of lncRNA RGMB-AS1 on proliferation, migration and epithelial mesenchymal transformation (EMT) of NPC by directly binding Forkhead box A1 (FOXA1) in vitro and in vivo. In conclusion, LncRNA RGMB-AS1 inhibits malignant behaviors and EMT by regulating FOXA1, and lncRNA RGMB-AS1 may be an important indicator of clinical prognosis.

Screening and Bioinformatics Analysis of Competitive Endogenous RNA Regulatory Network --Related to Circular RNA in Breast Cancer

Purpose

Circular RNA as a competitive endogenous RNA (ceRNA) plays a significant role in the pathogenesis and progression of breast cancer. In this study, a circular RNA-related ceRNA regulatory network was constructed, which provides new biomarkers and therapeutic targets for the treatment of breast cancer. Materials and methods. The expression profile datasets (GSE101123, GSE143564, GSE50428) of circRNAs, miRNAs, and mRNAs were downloaded from the GEO database, and then differentially expressed RNAs (DEcircRNAs, DEmiRNAs, DEmRNAs) were obtained through the CSCD, TargetScan, miRDB, and miRTarBase databases. CircRNA-miRNA pairs and miRNA-mRNA pairs were constructed. Finally, a ceRNA regulatory network was established. Downstream analysis of the ceRNA network included GO, KEGG analysis, survival analysis, sub-network construction, the BCIP, and qRT-PCR verification.

Results

In total, 144 differentially expressed (DE) DEcircRNA, 221 DEmiRNA, and 1211 DEmRNA were obtained, and 96 circRNA-miRNA pairs and 139 miRNA-mRNA pairs were constructed by prediction. The ceRNA regulatory network (circRNA-miRNA-mRNA) was constructed, which included 42 circRNA, 36miRNA, and 78 mRNA. GO function annotation showed genes were mainly enriched in receptor activity activated by transforming growth factor beta (TGF-beta) and in the regulation of epithelial cell apoptosis. KEGG analysis showed genes were mainly enriched in the TGF-beta signaling, PI3K-Akt signaling, and Wnt signaling pathways. Four genes associated with survival and prognosis of breast cancer were obtained by survival analysis, the prognostic sub-network included 4 circRNA, 4 miRNA, and 4 mRNA. BCIP analysis and qRT-PCR verification confirmed that relative mRNA expression levels were consistent with those in the GEO database.

Conclusion

A circRNA-related ceRNA regulatory network was constructed for breast cancer in this study and key genes affecting pathogenesis and progression were identified. These findings may help better understand and further explore the molecular mechanisms that affect the progression and pathogenesis of breast cancer.

KLF5 regulates epithelial-mesenchymal transition of liver cancer cells in the context of p53 loss through miR-192 targeting of ZEB2

Krüppel-like factor 5 (KLF5) can both promote and suppress cell migration, but the underlying mechanisms have not been elucidated. In this study, we show that the function of KLF5 in epithelial-mesenchymal transition (EMT) and migration of liver cancer cells depends on the status of the cellular tumor antigen p53 (p53). Furthermore, zinc finger E-box-binding homeobox 2 (ZEB2) is the main regulator of KLF5 in EMT in liver cancer cells in the context of p53 loss. Most importantly, the regulation of ZEB2 by p53 and KLF5 is indirect and that miR-192 mediates this regulation. Finally, we find that in invasive liver cancer, KLF5 is absent in the context of p53 loss or mutation.

Non-Coding RNAs in the Cardiac Action Potential and Their Impact on Arrhythmogenic Cardiac Diseases

Cardiac arrhythmias are prevalent among humans across all age ranges, affecting millions of people worldwide. While cardiac arrhythmias vary widely in their clinical presentation, they possess shared complex electrophysiologic properties at cellular level that have not been fully studied. Over the last decade, our current understanding of the functional roles of non-coding RNAs have progressively increased. microRNAs represent the most studied type of small ncRNAs and it has been demonstrated that miRNAs play essential roles in multiple biological contexts, including normal development and diseases. In this review, we provide a comprehensive analysis of the functional contribution of non-coding RNAs, primarily microRNAs, to the normal configuration of the cardiac action potential, as well as their association to distinct types of arrhythmogenic cardiac diseases.

Epithelial to mesenchymal transition and microRNA expression are associated with spindle and apocrine cell morphology in triple-negative breast cancer

Triple negative breast cancers (TNBC) are a morphologically and genetically heterogeneous group of breast cancers with uncertain prediction of biological behavior and response to therapy. Epithelial to mesenchymal transition (EMT) is a dynamic process characterized by loss of typical epithelial phenotype and acquisition of mesenchymal characteristics. Aberrant activation of EMT can aggravate the prognosis of patients with cancer, however, the mechanisms of EMT and role of microRNAs (miRNAs) in EMT activation is still unclear. The aim of our study was to analyze miRNA expression within areas of TNBCs with cellular morphology that may be related to the EMT process and discuss possible associations. Out of all 3953 re-examined breast cancers, 460 breast cancers were diagnosed as TNBC (11.64%). With regard to complete tumor morphology preservation, the tissue samples obtained from core—cut biopsies and influenced by previous neoadjuvant therapy were excluded. We assembled a set of selected 25 cases to determine miRNA expression levels in relation to present focal spindle cell and apocrine cell morphology within individual TNBCs. We used descriptive (histological typing and morphology), morphometric, molecular (microdissection of tumor and non-tumor morphologies, RNA isolation and purification, microchip analysis) and bioinformatic analysis (including pathway analysis). The results were verified by quantitative real-time PCR (RT-qPCR) on an extended set of 70 TNBCs. The majority of TNBCs were represented by high—grade invasive carcinomas of no special type (NST) with medullary features characterized by well-circumscribed tumors with central necrosis or fibrosis and frequent tendency to spindle-cell and/or apocrine cell transformation. Apocrine and spindle cell transformation showed a specific miRNA expression profile in comparison to other tumor parts, in situ carcinoma or non-tumor structures, particularly down-regulated expression of hsa-miRNA-143-3p and hsa-miRNA-205-5p and up-regulated expression of hsa-miR-22-3p, hsa-miRNA-185-5p, and hsa-miR-4443. Apocrine cell tumor morphology further revealed decreased expression of hsa-miR-145-5p and increased expression of additional 14 miRNAs (e.g. hsa-miR-182-5p, hsa-miR-3135b and hsa-miR-4417). Pathway analysis for target genes of these miRNAs revealed several shared biological processes (i.e. Wnt signaling, ErbB signaling, MAPK signaling, endocytosis and axon guidance), which may in part contribute to the EMT and tumor progression. We provide the first miRNA expression profiling of specific tissue morphologies in TNBC. Our results demonstrate a specific miRNA expression profile of apocrine and spindle cell morphology which can exhibit a certain similarity with the EMT process and may also be relevant for prognosis and therapy resistance of TNBC.

Non-Coding RNAs in Retinoic Acid as Differentiation and Disease Drivers

All-trans retinoic acid (RA) is the most active metabolite of vitamin A. Several studies have described a pivotal role for RA signalling in different biological processes such as cell growth and differentiation, embryonic development and organogenesis. Since RA signalling is highly dose-dependent, a fine-tuning regulatory mechanism is required. Thus, RA signalling deregulation has a major impact, both in development and disease, related in many cases to oncogenic processes. In this review, we focus on the impact of ncRNA post-transcriptional regulatory mechanisms, especially those of microRNAs and lncRNAs, in RA signalling pathways during differentiation and disease.

Regulation of breast cancer metastasis signaling by miRNAs

Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.

Tackle Epithelial-Mesenchymal Transition With Epigenetic Drugs in Cancer

Epithelial-mesenchymal Transition (EMT) is a de-differentiation process in which epithelial cells lose their epithelial properties to acquire mesenchymal features. EMT is essential for embryogenesis and wound healing but is aberrantly activated in pathological conditions like fibrosis and cancer. Tumor-associated EMT contributes to cancer cell initiation, invasion, metastasis, drug resistance and recurrence. This dynamic and reversible event is governed by EMT-transcription factors (EMT-TFs) with epigenetic complexes. In this review, we discuss recent advances regarding the mechanisms that modulate EMT in the context of epigenetic regulation, with emphasis on epigenetic drugs, such as DNA demethylating reagents, inhibitors of histone modifiers and non-coding RNA medication. Therapeutic contributions that improve epigenetic regulation of EMT will translate the clinical manifestation as treating cancer progression more efficiently.

Novel MicroRNA Binding Site SNPs and the Risk of Clear Cell Renal Cell Carcinoma (ccRCC): A Case-Control Study

BACKGROUND

Renal cell carcinoma represents 3% of all adult malignancies. MicroRNAs exhibit specific functions in various biological processes through their interaction with cellular mRNA involved in apoptosis and cell cycle control. Recent studies have reported the potential association of single-nucleotide polymorphisms (SNPs) in miRNA-binding sites of VHL-HIF1α pathway genes with renal cancer development and progression.

OBJECTIVE

The objective of this study is to investigate SNPs invoking an alteration in the nature of interaction with miRNA binding sites of VHL-HIF1α pathway genes.

PATIENTS & METHODS

Total 450 cases of histologically and clinically verified ccRCC and 490 controls were included in our study. Genotyping was performed using a TaqMan PCR allelic discrimination method. Kaplan-Meier method of statistical analysis was implemented to analyze the overall patient survival rate.

RESULTS

Polymorphism rs10491534 in TSC1 gene was significantly associated with risk of developing advanced ccRCC. Allele G of rs1642742 in VHL gene was significantly prevalent in ccRCC compared with control group aged 55 and older (OR = 1.5566; CI [1.1532-2.1019]). Results from the dominant model combining individuals with AG or AA genotype showed that the A allele bearers of CDCP1 rs6773576 exhibited higher risk of death compared to GG carriers (HR 3.93, 95% CI 1.76-17.21, log-rank P = 0.0033).

CONCLUSION

The present study delineated the association of miRNA binding site variants in VHL-HIF1α pathway genes with the ccRCC risk, which may affect clinical outcome.

miR-362-3p suppresses sinonasal squamous cell carcinoma progression via directly targeting pituitary tumor-transforming gene 1

BACKGROUND

Sinonasal squamous cell carcinoma (SNSCC) is a main subtype of sinonasal malignancy with unclear pathogenesis. microRNAs (miRNAs) are involved in SNSCC progression. Nevertheless, the role and mechanism of miR-362-3p in SNSCC development are unclear.

METHODS

The SNSCC tissues (n = 23) and normal sinonasal samples (n = 13) were harvested. SNSCC cell line RPMI-2650 cells were transfected using Lipofectamine 3000. miR-362-3p and pituitary tumor-transforming gene 1 (PTTG1) were determined by quantitative reverse transcription polymerase chain reaction and western blot. Cell proliferation was analyzed via Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell migration and invasion was assessed using wound healing assay and transwell assay. Epithelial-mesenchymal transition (EMT)-associated protein (E-cadherin, N-cadherin and Vimentin) levels were measured via western blot. The binding relationship was analyzed via bioinformatic analysis and dual-luciferase reporter assay.

RESULTS

miR-362-3p abundance was decreased in SNSCC samples. miR-362-3p addition constrained cell proliferation, migration, invasion and EMT, but miR-362-3p knockdown played an opposite effect. PTTG1 was targeted and negatively modulated by miR-362-3p. PTTG1 abundance was elevated in SNSCC samples. PTTG1 overexpression mitigated miR-362-3p-modulated suppression of cell proliferation, migration, invasion and EMT in SNSCC cells.

CONCLUSION

miR-362-3p repressed cell proliferation, migration, invasion and EMT in SNSCC via targeting PTTG1.

Non-coding RNAs and Atrial Fibrillation

Atrial fibrillation is the most frequent type of cardiac arrhythmia in humans, with an estimate incidence of 1-2% in the general population, rising up to 8-10% in the elderly. Cardiovascular risk factors such as diabetes, obesity, hypertension and hyperthyroidism can increase the occurrence of AF. The onset of AF triggers additional AF episodes, leading to structural and electrical remodeling of the diseased heart. Understanding the molecular bases of atrial fibrillation have greatly advance over the last decade demonstrating a pivotal role of distinct ion channels in AF pathophysiology. A new scenario has opened on the understanding of the molecular mechanisms underlying AF, with the discovery of non-coding RNAs and their wide implication in multiple disease states, including cardiac arrhythmogenic pathologies. microRNAs are small non-coding RNAs of 22-24 nucleotides that are capable of regulating gene expression by interacting with the mRNA transcript 3'UTRs and promoting mRNA degradation and/or protein translation blockage. Long non-coding RNAs are a more diverse group of non-coding RNAs, providing transcriptional and post-transcriptional roles and subclassified according to their functional properties. In this chapter we summarized current state-of-the-art knowledge on the functional of microRNAs and long non-coding RNAs as well as their cross-talk regulatory mechanisms in atrial fibrillation.

MiR-195 enhances cardiomyogenic differentiation of the proepicardium/septum transversum by Smurf1 and Foxp1 modulation

Cardiovascular development is a complex developmental process in which multiple cell lineages are involved, namely the deployment of first and second heart fields. Beside the contribution of these cardiogenic fields, extracardiac inputs to the developing heart are provided by the migrating cardiac neural crest cells and the proepicardial derived cells. The proepicardium (PE) is a transitory cauliflower-like structure located between the cardiac and hepatic primordia. The PE is constituted by an internal mesenchymal component surrounded by an external epithelial lining. With development, cells derived from the proepicardium migrate to the neighboring embryonic heart and progressive cover the most external surface, leading to the formation of the embryonic epicardium. Experimental evidence in chicken have nicely demonstrated that epicardial derived cells can distinctly contribute to fibroblasts, endothelial and smooth muscle cells. Surprisingly, isolation of the developing PE anlage and ex vivo culturing spontaneously lead to differentiation into beating cardiomyocytes, a process that is enhanced by Bmp but halted by Fgf administration. In this study we provide a comprehensive characterization of the developmental expression profile of multiple microRNAs during epicardial development in chicken. Subsequently, we identified that miR-125, miR-146, miR-195 and miR-223 selectively enhance cardiomyogenesis both in the PE/ST explants as well as in the embryonic epicardium, a Smurf1- and Foxp1-driven process. In addition we identified three novel long non-coding RNAs with enhanced expression in the PE/ST, that are complementary regulated by Bmp and Fgf administration and well as by microRNAs that selectively promote cardiomyogenesis, supporting a pivotal role of these long non coding RNAs in microRNA-mediated cardiomyogenesis of the PE/ST cells.

The Role of Epithelial-to-Mesenchymal Transition in Cutaneous Squamous Cell Carcinoma : Epithelial-to-Mesenchymal Transition in Cutaneous SCC

OPINION STATEMENT

The capacity of cells to modify their phenotypes from epithelial to mesenchymal (epithelial-to-mesenchymal transition or EMT) and vice versa provides them with a dynamic plasticity essential for human life, from embryogenesis to wound healing. Current knowledge about carcinogenetic mechanisms leaves little doubts on the pivotal participation of these interchangeable processes in cancer development, and their influence has been quite clearly established in the progression of cutaneous squamous cell carcinoma. A complex and ordered interplay of signals induces the shift between both phenotypes, providing cells with the most suitable state at every moment to face the next step in tumor invasion and dissemination. Some stimulatory triggers have opposite effects according to the biological context and in many cases exert collateral functions. This scenario makes finding an ideal therapeutic target difficult but provides the opportunity to intervene simultaneously at many different levels with small actions such as targeting the tumor environment. In any case, advances in knowledge of the EMT mechanisms and their influence on carcinogenesis and drug resistance will greatly influence the therapeutic strategies for many human tumors, including cutaneous squamous cell carcinoma.

Sequencing and Functional Annotation of the Whole Genome of Shiraia bambusicola

Shiraia bambusicola is a rare medicinal fungus found in China that causes bamboo plants to decay and die with severe infection. Hypocrellin, its main active ingredient, is widely used in several fields, such as medicine, agriculture, and food industry. In this study, to clarify the genomic components, taxonomic status, pathogenic genes, secondary metabolite synthesis pathways, and regulatory mechanisms of S. bambusicola, whole-genome sequencing, assembly, and functional annotation were performed using high-throughput sequencing and bioinformatics approaches. It was observed that S. bambusicola has 33 Mb genome size, 48.89% GC content, 333 scaffolds, 2590 contigs, 10,703 genes, 82 tRNAs, and 21 rRNAs. The total length of the repeat sequence is 2,151,640 bp. The annotation of 5945 proteins was obtained from InterProScan hits based on the Gene Ontology database. Phylogenetic analysis showed that S. bambusicola belongs to Shiraiaceae, a new family of Pleosporales. It was speculated that there are more than two species or genus in Shiraiaceae. According to the annotation, 777 secreted proteins were associated with virulence or detoxification, including 777 predicted by the PHI database, 776 by the CAZY and Fungal CytochromeP450 database, and 441 by the Proteases database. The 252 genes associated with the secondary metabolism of S. bambusicola were screened and enriched into 28 pathways, among which the terpenoids, staurosporine, aflatoxin, and folate synthesis pathways have not been reported in S. bambusicola. The T1PKS was the main gene cluster among the 28 secondary metabolite synthesis gene clusters in S. bambusicola. The analysis of the T3PKS gene cluster related to the synthesis of hypocrellin showed that there was some similarity between S. bambusicola and 10 other species of fungi; however, the similarity was very low wherein the highest similarity was 17%. The genomic information of S. bambusicola obtained in this study was valuable to understand its genetic function and pathogenicity. The genomic information revealed that several enzyme genes and secreted proteins might be related to their host interactions and pathogenicity. The annotation and analysis of its secondary metabolite synthesis genes and gene clusters will be an important reference for future studies on the biosynthesis and regulation mechanism of the secondary metabolites, contributing to the discovery of new metabolites and accelerating drug development and application.

Differential chamber-specific expression and regulation of long non-coding RNAs during cardiac development

Cardiovascular development is governed by a complex interplay between inducting signals such as Bmps and Fgfs leading to activation of cardiac specific transcription factors such as Nkx2.5, Mef2c and Srf that orchestrate the initial steps of cardiogenesis. Over the last decade we have witnessed the discovery of novel layers of gene regulation, i.e. post-transcriptional regulation exerted by non-coding RNAs. The function role of small non coding RNAs has been widely demonstrated, e.g. miR-1 knockout display several cardiovascular abnormalities during embryogenesis. More recently long non-coding RNAs have been also reported to modulate gene expression and function in the developing heart, as exemplified by the embryonic lethal phenotypes of Fendrr and Braveheart knock out mice, respectively. In this study, we investigated the differential expression profile during cardiogenesis of previously reported lncRNAs in heart development. Our data revealed that Braveheart, Fendrr, Carmen display a preferential adult expression while Miat, Alien, H19 preferentially display chamber-specific expression at embryonic stages. We also demonstrated that these lncRNAs are differentially regulated by Nkx2.5, Srf and Mef2c, Pitx2 > Wnt > miRNA signaling pathway and angiotensin II and thyroid hormone administration. Importantly isoform-specific expression and distinct nuclear vs cytoplasmic localization of Braveheart, Carmen and Fendrr during chamber morphogenesis is observed, suggesting distinct functional roles of these lncRNAs in atrial and ventricular chambers. Furthermore, we demonstrate by in situ hybridization a dynamic epicardial, myocardial and endocardial expression of H19 during cardiac development. Overall our data support novel roles of these lncRNAs in different temporal and tissue-restricted fashion during cardiogenesis.

Helicobacter pylori-activated gastric fibroblasts induce epithelial-mesenchymal transition of gastric epithelial cells in vitro in a TGF-β-dependent manner

BACKGROUND

Colonization of the gastric mucosa with Helicobacter pylori (Hp) leads to the cascade of pathologic events including local inflammation, gastric ulceration, and adenocarcinoma formation. Paracrine loops between tissue cells and Hp contribute to the formation of gastric cancerous loci; however, the specific mechanisms underlying existence of these loops remain unknown. We determined the phenotypic properties of gastric fibroblasts exposed to Hp (cagA+vacA+) infection and their influence on normal epithelial RGM-1 cells.

MATERIALS AND METHODS

RGM-1 cells were cultured in the media conditioned with Hp-activated gastric fibroblasts. Their morphology and phenotypical changes associated with epithelial-mesenchymal transition (EMT) were assessed by Nomarski and fluorescence microscopy and Western blot analysis. Motility pattern of RGM-1 cells was examined by time-lapse video microscopy and transwell migration assay. The content of TGF-β in Hp-activated fibroblast-conditioned media was determined by ELISA.

RESULTS

The supernatant from Hp-activated gastric fibroblasts caused the EMT-like phenotypic diversification of RGM-1 cells. The formation of fibroblastoid cell sub-populations, the disappearance of their collective migration, an increase in transmigration potential with downregulation of E-cadherin and upregulation of N-cadherin proteins, prominent stress fibers, and decreased proliferation were observed. The fibroblast (CAF)-like transition was manifested by increased secretome TGF-β level, α-SMA protein expression, and its incorporation into stress fibers, and the TGF-βR1 kinase inhibitor reduced the rise in Snail, Twist, and E-cadherin mRNA and increased E-cadherin expression induced by CAFs.

CONCLUSION

Gastric fibroblasts which are one of the main targets for Hp infection contribute to the paracrine interactions between Hp, gastric fibroblasts, and epithelial cells. TGF-β secreted by Hp-activated gastric fibroblasts prompting their differentiation toward CAF-like phenotype promotes the EMT-related phenotypic shifts in normal gastric epithelial cell populations. This mechanism may serve as the prerequisite for GC development.

MicroRNA-27a (miR-27a) in Solid Tumors: A Review Based on Mechanisms and Clinical Observations

MicroRNAs (miRNAs) are a family of highly conserved, non-coding single-stranded RNAs transcribed as ~70 nucleotide precursors to an 18–22 nucleotide product (1). miRNAs can silence their homologous target genes at the post-transcriptional level, and these genes have been revealed to play an important role in tumorigenesis, invasion and metastasis (2). MicroRNA-27a (miR-27a), transcripted by miR-27a gene, has proved to implicate with many kinds of solid tumors, showing potential as a useful biomarker or drug target for clinical application. However, even though miR-27a has been reported in many cancers, the mechanism and signal pathways of miR-27 in oncogenesis, invasion, and metastasis are still obscure. Moreover, recent studies show that miR-27a pays an important role in epithelial-mesenchymal-transition, regulating tumor immune response, and chemoresistance. In this review, we summarize the current literature, demonstrate the established link between miR-27a and tumorigenesis, and focus on recently identified mechanisms. The review also aims to demonstrate the potential of miR-27a as a diagnostic and/or prognostic biomarker in solid tumors and to discuss the possibilities of targeted therapy and drug design.

Celecoxib inhibits the epithelial-to-mesenchymal transition in bladder cancer via the miRNA-145/TGFBR2/Smad3 axis

Celecoxib, a selective cyclooxygenase-2 inhibitor, has chemo-preventive activity against different cancer types, including bladder cancer (BC). However, the mechanisms by which celecoxib exerts its cancer preventative effects have yet to be completely understood. In the present study, the effect of celecoxib on the epithelial-to-mesenchymal transition (EMT) of BC cells and its potential molecular mechanisms were investigated. The results of the present study demonstrated that celecoxib inhibited the proliferation, migration, invasion and EMT of BC cells. Further investigation of the underlying mechanism revealed that celecoxib inhibited EMT by upregulating microRNA (miR)-145 and downregulating the expression of transforming growth factor β receptor 2 and SMAD family member 3. Furthermore, the combination of celecoxib with miR-145 mimics demonstrated an additive migration and invasion-inhibitory effect in BC cell lines.

TGF-β-Mediated Epithelial-Mesenchymal Transition and Cancer Metastasis

Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings, TGF-β plays a key role in controlling embryogenic development, inflammation, and tissue repair, as well as in maintaining adult tissue homeostasis. TGF-β elicits a broad range of context-dependent cellular responses, and consequently, alterations in TGF-β signaling have been implicated in many diseases, including cancer. During the early stages of tumorigenesis, TGF-β acts as a tumor suppressor by inducing cytostasis and the apoptosis of normal and premalignant cells. However, at later stages, when cancer cells have acquired oncogenic mutations and/or have lost tumor suppressor gene function, cells are resistant to TGF-β-induced growth arrest, and TGF-β functions as a tumor promotor by stimulating tumor cells to undergo the so-called epithelial-mesenchymal transition (EMT). The latter leads to metastasis and chemotherapy resistance. TGF-β further supports cancer growth and progression by activating tumor angiogenesis and cancer-associated fibroblasts and enabling the tumor to evade inhibitory immune responses. In this review, we will consider the role of TGF-β signaling in cell cycle arrest, apoptosis, EMT and cancer cell metastasis. In particular, we will highlight recent insights into the multistep and dynamically controlled process of TGF-β-induced EMT and the functions of miRNAs and long noncoding RNAs in this process. Finally, we will discuss how these new mechanistic insights might be exploited to develop novel therapeutic interventions.

The expression level changes of microRNAs 200a/205 in the development of invasive properties in gastric cancer cells through epithelial-mesenchymal transition

EMT (Epithelial-Mesenchymal Transition) is a highly regulated process that results in cancer progression. MicroRNA plays a significant role in the regulation of EMT through tight control of the transcription factors. In this study, we focus on miR-200a/205 as a factor involved in the control of the EMT process in gastric cancer cells. In this sense, gastric adenocarcinoma cell lines were used to induce EMT process. For characterization of EMT process, the mRNA levels of E-cadherin, Vimentin, β-catenin, ZEB1 and Snail were measured by real time PCR. In addition, Western blot approach was adopted to determine the protein levels of these EMT markers. Transwell assay revealed migration and invasion property of gastric cancer cell after EMT induction. To analyze alteration amount of microRNAs, RT-PCR was applied. Our results confirmed the establishment of in vitro EMT model. In vitro study showed a significant negative correlation between the expression of miR-200a (P = 0.001) and expression level of EMT markers. Nevertheless, miR-205 did not show any significant results in correlation with EMT in AGS cell line. All in vitro results also were validated in gastric cancer tissue samples. Based on our findings from gastric cancer sample patients and in vitro results, miR-200a is down regulated. Therefore, in further investigation, miR-200a could be used as a candidate to prevent the invasive properties of gastric cancer through the EMT process.

Molecular Mechanisms in Clear Cell Renal Cell Carcinoma: Role of miRNAs and Hypermethylated miRNA Genes in Crucial Oncogenic Pathways and Processes

Clear cell renal cell carcinoma (ccRCC) is the third most common urological cancer, and it has the highest mortality rate. The increasing drug resistance of metastatic ccRCC has resulted in the search for new biomarkers. Epigenetic regulatory mechanisms, such as genome-wide DNA methylation and inhibition of protein translation by interaction of microRNA (miRNA) with its target messenger RNA (mRNA), are deeply involved in the pathogenesis of human cancers, including ccRCC, and may be used in its diagnosis and prognosis. Here, we review oncogenic and oncosuppressive miRNAs, their putative target genes, and the crucial pathways they are involved in. The contradictory behavior of a number of miRNAs, such as suppressive and anti-metastatic miRNAs with oncogenic potential (for example, miR-99a, miR-106a, miR-125b, miR-144, miR-203, miR-378), is examined. miRNAs that contribute mostly to important pathways and processes in ccRCC, for instance, PI3K/AKT/mTOR, Wnt-β, histone modification, and chromatin remodeling, are discussed in detail. We also separately consider their participation in crucial oncogenic processes, such as hypoxia and angiogenesis, metastasis, and epithelial-mesenchymal transition (EMT). The review also considers the interactions of long non-coding RNAs (lncRNAs) and miRNAs of significance in ccRCC. Recent advances in the understanding of the role of hypermethylated miRNA genes in ccRCC and their usefulness as biomarkers are reviewed based on our own data and those available in the literature. Finally, new data and perspectives concerning the clinical applications of miRNAs in the diagnosis, prognosis, and treatment of ccRCC are discussed.

Knockdown of lncRNA GHET1 inhibits osteosarcoma cells proliferation, invasion, migration and EMT in vitro and in vivo

OBJECTIVE

Osteosarcoma is the most common primary malignant skeleton tumor that derives from mesenchymal cells. Emerging evidences have identified the vital role of long non-coding RNAs (lncRNAs) in the development of osteosarcoma. In this study, we aimed to investigate the role of lncRNA gastric carcinoma highly expressed transcript 1 (GHET1) in osteosarcoma progression.

METHODS

The expression levels of relevant genes in clinical samples and cell lines were determined by quantitative real-time PCR. Cell proliferation was determined by CCK8 and cell colony formation assays. Transwell assay was used to detect the invasion and migration of osteosarcoma cells. Cell apoptosis and cell cycle were detected by flow cytometry. Protein levels were detected by western blot. In vivo tumor growth was investigated in the xenograft nude mice model. To determine whether growth inhibition and apoptosis are responsible for antitumor activity of silencing GHET1, immunohistochemistry for proliferation and TUNEL assay was performed in xenograft tissues. In vivo lung metastasis was performed to detect the effect of GHET1 on cell metastasis ability.

RESULTS

Our results revealed that GHET1 was up-regulated in osteosarcoma tissues compared to normal tissues. GHET1 was also increased in osteosarcoma cell lines compared to normal osteoplastic cell line. The up-regulation of GHET1 was significantly associated with TNM stage, distant metastasis and lymph node metastasis in patients with osteosarcoma. In vitro studies showed that silencing GHET1 in MG-63 and U2OS cells inhibited cell proliferation, cell invasion and migration and epithelial-to-mesenchymal transition (EMT), promoted cell apoptotic rate, and also caused an increase in cell population at G0/G1 phase with a decrease in cell population at S phase. Overexpression of GHET1 promoted the proliferation, invasion and migration of osteosarcoma cells. Importantly, silencing GHET1 inhibited tumor growth and tumor metastasis in mice MG-63-xenograft model in association with changes of EMT-related genes, reduced expression of Ki-67 and promotion of apoptosis.

CONCLUSION

GHET1 was up-regulated in osteosarcoma tissues and cell lines, inhibited cell apoptosis, promoted cell proliferation, invasion and migration by affecting EMT in vitro, and was correlated with the tumor growth and metastasis in vivo. GHET1 may be a potential therapeutic target of osteosarcoma treatment.

The Role of Non-Coding RNA in Congenital Heart Diseases

Cardiovascular development is a complex developmental process starting with the formation of an early straight heart tube, followed by a rightward looping and the configuration of atrial and ventricular chambers. The subsequent step allows the separation of these cardiac chambers leading to the formation of a four-chambered organ. Impairment in any of these developmental processes invariably leads to cardiac defects. Importantly, our understanding of the developmental defects causing cardiac congenital heart diseases has largely increased over the last decades. The advent of the molecular era allowed to bridge morphogenetic with genetic defects and therefore our current understanding of the transcriptional regulation of cardiac morphogenesis has enormously increased. Moreover, the impact of environmental agents to genetic cascades has been demonstrated as well as of novel genomic mechanisms modulating gene regulation such as post-transcriptional regulatory mechanisms. Among post-transcriptional regulatory mechanisms, non-coding RNAs, including therein microRNAs and lncRNAs, are emerging to play pivotal roles. In this review, we summarize current knowledge on the functional role of non-coding RNAs in distinct congenital heart diseases, with particular emphasis on microRNAs and long non-coding RNAs.

miR-181a/b therapy in lung cancer: reality or myth?

Despite substantial progress in oncology, lung cancer remains the number one malignancy in terms of both incidence and mortality rates, and there thus remains an urgent need for new therapeutic alternatives. MicroRNA (miRNA) have an important role in cancer initiation and progression due to their capacity to interfere with transcriptional signaling and regulate key cellular processes. miR-181a and miR-181b (miR-181a/b), which are located on chromosomes 1 and 9, are pathologically expressed in the tumor tissue and plasma of patients diagnosed with lung cancer. The miR-181a/b regulatory mechanisms are sophisticated and are directly related to different target genes. In recent years, an ever-increasing number of studies have focused on the biological relevance of miR-181a/b in key cellular processes. In this paper, we aim to discuss the challenging experimental data related to miR-181a/b and their potential use for the development of new therapeutic approaches in lung cancer. We will further present the ongoing issues regarding the regulation of their multiple target genes, and their potential use as biomarkers and therapeutic targets in this deadly malignancy.