Knockdown of miR-214 promotes apoptosis and inhibits cell proliferation in nasopharyngeal carcinoma

Inhibition of miR-214 expression by small molecules alleviates head and neck cancer metastasis by targeting ALCAM/TFAP2 signaling

Predominantly, head and neck cancer (HNC) is considered a regional disease and develops in the nasal cavity, oral cavity, tongue, pharynx, and larynx. In the advanced stage, the HNC spread into distant organs. By the time head and neck cancer diagnosed, the estimated metastasis is occurred in 10-40% cases. The most important vital organs affected by distant metastasis are the lungs, bones, and liver. Despite several advancements in chemotherapies, no significant changes are observed as 5-year survival rate remains the same. Therefore, it is crucial to decipher molecular mechanisms contributing to the metastatic dissemination of head and neck cancer. Here, we tested a novel ALCAM/TFAP2 signaling by targeting multidisciplinary miR-214 expression in head and cancer cells. Our results revealed that HNC cell lines (CAL27, SCC-9, SCC-4, and SCC-25) exhibit higher expression of miR-214 compared with normal human bronchial epithelial (NHBE) cells. Higher expression of miR-214 drives the invasive potential of these cell lines. Down-regulation of miR-214 in CAL27 and SCC-9 cells either using an anti-miR-214 inhibitor (50nM) or a small molecule of green tea (EGCG) inhibited cell invasion. Treating CAL27 and SCC-9 cells with EGCG also reduces ALCAM expression, a key activated leukocyte cell adhesion molecule, potentially blocking mesenchymal phenotype. Dietary administration of EGCG significantly inhibits distant metastasis of SCC-9 cells into the lungs, liver, and kidneys. Our results also demonstrate that the reduction of miR-214 expression influences in vitro cell movement and extravasation, as evident by reduced CD31 expression, a neovascularization marker. Together, these studies suggest that identifying bioactive molecules that can inhibit distant metastasis regulated by the miRNAs may provide potent interventional approaches and a better understanding of the complex functions of miRNAs and their therapeutic targets for clinical application.

LncRNA GAS5 upregulates miR-214 through methylation to participate in cell apoptosis of sepsis

It has been reported that lncRNA GAS5 can inhibit LPS-induced inflammation, indicating its involvement in sepsis. We observed the downregulation of GAS5 in plasma of sepsis patients. In addition, expression levels of GAS5 were positively correlated with the expression levels of miR-214. In cardiomyocytes, overexpression of GAS5 upregulated the expression of miR-214, while its knockdown resulted in decreased expression levels of miR-124. Methylation-specific PCR (MSP) revealed that GAS5 negatively regulated the methylation of miR-124. Cell apoptosis showed that overexpression of GAS5 and miR-214 suppressed the apoptosis of cardiomyocytes induced by LPS. In addition, overexpression of miR-214 also reduced the enhancing effects of silencing of GAS5 on cell apoptosis. Therefore, GAS5 may upregulate miR-214 through methylation pathway to inhibit the apoptosis of cardiomyocytes in sepsis.

Regulation of Ferroptosis by Non-Coding RNAs in Head and Neck Cancers

Ferroptosis is a newly identified mode of programmed cell death characterized by iron-associated accumulation of lipid peroxides. Emerging research on ferroptosis has suggested its implication in tumorigenesis and stemness of cancer. On the other hand, non-coding RNAs have been shown to play a pivotal role in the modulation of various genes that affect the progression of cancer cells and ferroptosis. In this review, we summarize recent advances in the theoretical modeling of ferroptosis and its relationship between non-coding RNAs and head and neck cancers. Aside from the significance of ferroptosis-related non-coding RNAs in prognostic relevance, we also review how these non-coding RNAs participate in the regulation of iron, lipid metabolism, and reactive oxygen species accumulation. We aim to provide a thorough grounding in the function of ferroptosis-related non-coding RNAs based on current knowledge in an effort to develop effective therapeutic strategies for head and neck cancers.

MicroRNA-214 in Health and Disease

MicroRNAs (miRNAs) are endogenously expressed, non-coding RNA molecules that mediate the post-transcriptional repression and degradation of mRNAs by targeting their 3′ untranslated region (3′-UTR). Thousands of miRNAs have been identified since their first discovery in 1993, and miR-214 was first reported to promote apoptosis in HeLa cells. Presently, miR-214 is implicated in an extensive range of conditions such as cardiovascular diseases, cancers, bone formation and cell differentiation. MiR-214 has shown pleiotropic roles in contributing to the progression of diseases such as gastric and lung cancers but may also confer cardioprotection against excessive fibrosis and oxidative damage. These contrasting functions are achieved through the diverse cast of miR-214 targets. Through silencing or overexpressing miR-214, the detrimental effects can be attenuated, and the beneficial effects promoted in order to improve health outcomes. Therefore, discovering novel miR-214 targets and understanding how miR-214 is dysregulated in human diseases may eventually lead to miRNA-based therapies. MiR-214 has also shown promise as a diagnostic biomarker in identifying breast cancer and coronary artery disease. This review provides an up-to-date discussion of miR-214 literature by describing relevant roles in health and disease, areas of disagreement, and the future direction of the field.

Circular RNA ITCH attenuates the progression of nasopharyngeal carcinoma by inducing PTEN upregulation via miR-214

BACKGROUND

Circular RNA itchy E3 ubiquitin protein ligase (circ-ITCH) has previously been reported to play a key role in carcinogenesis. Nevertheless, the role of circ-ITCH in nasopharyngeal carcinoma (NPC) remains to be explored.

METHODS

Gene expression analysis was performed using a quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry. The role of circ-ITCH in NPC was explored using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, colony formation, transwell invasion, scratch healing and xenograft tumor assays. Furthermore, luciferase reporter assay was carried out to assess the interactions among circ-ITCH, microRNA-214 (miR-214) and phosphatase and tensin homolog (PTEN).

RESULTS

The levels of circ-ITCH and PTEN were decreased, whereas the level of miR-214 was increased in NPC tissues collected from 28 subjects compared to normal nasopharynx tissues collected from 15 subjects. Moreover, a negative correlation between circ-ITCH and miR-214 expression and a positive correlation between circ-ITCH and PTEN expression were observed in NPC tissues. Downregulation of circ-ITCH expression was also observed in NPC cell lines. In addition, upregulation of circ-ITCH markedly inhibited NPC cell proliferation, migration and invasion. Furthermore, circ-ITCH was confirmed to exert its function by sponging miR-214. PTEN was found to be a direct target gene of miR-214 and its expression was negatively correlated with miR-214 expression in NPC tissues. Moreover, our results showed that the circ-ITCH/miR-214 axis regulated NPC proliferation, migration and invasion through regulating the expression of PTEN. Upregulation of circ-ITCH or PTEN blocked miR-214-mediated promotion of NPC tumorigenesis in vitro. Additionally, upregulation of circ-ITCH also suppressed NPC tumorigenesis in vivo.

CONCLUSIONS

The present study demonstrated that circ-ITCH suppressed NPC tumorigenesis by upregulating PTEN expression through interacting with miR-214, thus proposing a novel mechanism for NPC inhibition.

Cross-link between ferroptosis and nasopharyngeal carcinoma: New approach to radiotherapy sensitization

Ferroptosis is a recently discovered special type of regulated cell death that is strongly associated with both homeostasis maintenance and cancer development. Previous studies have indicated that a number of small-molecular agents inducing ferroptosis have great potential in the treatment of different types of cancer, including breast, pancreatic, prostate and head and neck cancer. However, the role of ferroptosis in nasopharyngeal carcinoma (NPC) has remained to be fully determined. To the best of our knowledge, no review of the currently available studies on this subject has been published to date. The metabolism and expression of specific genes that regulate ferroptosis may represent a promising radiosensitization target in cancer treatment. The aim of the present review was to describe the cross-link between ferroptosis and NPC and to discuss the potential value of regulators and the possible mechanism underlying the role of ferroptosis in the radiosensitization of NPC, in the hope that linking the mechanism of ferroptosis with the development of NPC will accelerate the development of novel ferroptosis-based targets and radiotherapy strategies in NPC.

microRNAs deregulation in head and neck squamous cell carcinoma

Head and neck (HN) squamous cell carcinoma (SCC) is the eighth most common human cancer worldwide. Besides tobacco and alcohol consumption, genetic and epigenetic alterations play an important role in HNSCC occurrence and progression. microRNAs (miRNAs) are small noncoding RNAs that regulate cell cycle, proliferation, development, differentiation, and apoptosis by interfering in gene expression. Expression profiling of miRNAs showed that some miRNAs are upregulated or downregulated in tumor cells when compared with the normal cells. The present review focuses on the role of miRNAs deregulations in HNSCC, enrolled in risk, development, outcome, and therapy sensitivity. Moreover, the influence of single nucleotide variants in miRNAs target sites, miRNAs seed sites, and miRNAs-processing genes in HNSCC was also revised. Due to its potential for cancer diagnosis, progression, and as a therapeutic target, miRNAs may bring new perspectives in HNSCC understanding and therapy, especially for those patients with no or insufficient treatment options.

MicroRNAs: Biogenesis, Functions and Potential Biomarkers for Early Screening, Prognosis and Therapeutic Molecular Monitoring of Nasopharyngeal Carcinoma

According to reports published, the aberrant expression of microRNAs (miRNAs), a class of 19–25 nucleotide-long small non-coding RNAs, is responsible for human cancers, including nasopharyngeal cancer (NPC). The dysregulation of miRNAs that act either as a tumor suppressor or oncogene, leading to a wide range of NPC pathogenesis pathways, includes the proliferation, invasion, migration as well as the metastasis of NPC cells. This article reviews and highlights recent advances in the studies of miRNAs in NPC, with a specific demonstration of the functions of miRNA, especially circulating miRNAs, in the pathway of NPC pathogenesis. Additionally, the possible use of miRNAs as early screening and prognostic biomarkers and for therapeutic molecular monitoring has been extensively studied.

MiR-214 Mediates Cell Proliferation and Apoptosis of Nasopharyngeal Carcinoma Through Targeting Both WWOX and PTEN

Background: This study aimed to investigate interactions between miR-214, PTEN, and WWOX and their effect on AKT signaling during the NPC progression. Nasopharyngeal carcinoma (NPC) was highly prevalent with poor prognosis among the patients. MiR-214 reported as an important NPC biomarker was associated with regulation of biological functions.

Methods: 5–8F and 6–10B NPC cells were transfected with miR-214 inhibitor. MTT and colony formation assays were performed to assess cell proliferation. PI staining assay was performed to determine distribution of cell cycle. Annexin-V/PI staining assay was used to evaluate cell apoptosis in NPC. The effects of miR-214 inhibitor on the expression levels of PTEN, WWOX, AKT signaling pathway, cell-cycle-, and apoptosis-associated proteins were assessed by Western blotting or qRT-PCR assay. PTEN and WWOX were knocked down using the corresponding shRNA to investigate their effects on miR-214 inhibitor involved in proapoptosis and antiproliferation mechanisms in NPC.

Results: Inhibition of miR-214 suppressed cell growth and induced apoptosis of 5–8F and 6–10B cells. MiR-214 regulated the expression of both PTEN and WWOX through targeting the 3′-UTR. Inhibition of miR-214 promoted WWOX and PTEN expression, inactivated AKT signaling pathway, and regulated cell-cycle- and apoptosis-associated proteins. Knockdown of PTEN or WWOX reversed effects of miR-214 inhibitor on AKT signaling, cell proliferation, and apoptosis.

Conclusion: MiR-214 was suggested to induce cell proliferation and inhibit cell apoptosis of NPC through directly targeting both PTEN and WWOX, which provided a novel therapeutic target for clinical treatment of NPC.

Circulating miR-214-3p predicts nasopharyngeal carcinoma recurrence or metastasis

BACKGROUND

Due to the remarkably stable form in the bloodstream, circulating microRNAs (miRNAs) are indicated as promising novel minimally invasive biomarkers in many cancers. However, available data of miRNAs in nasopharyngeal carcinoma (NPC) are relatively limited.

METHODS

Based on the GEO database and previous published reports, 21 dysregulated miRNAs were selected for screening via microarray analysis (20 NPC samples vs 10 controls). Dysregulated miRNAs were then detected and verified by the method of quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in the training and validation sets. The candidate miR-214-3p was then evaluated in the evaluation set, including the association between miR-214-3p and clinicopathological characteristics, dynamic changes in NPC patients and the predictive value for NPC recurrence or metastasis.

RESULTS

Seven miRNAs were significantly altered in comparison with healthy controls by microarray analysis. MiR-214-3p was the most significantly expressed in training and validation sets by qRT-PCR. Plasma miR-214-3p expressions were significantly associated with UICC stages and NPC recurrence or metastasis. Plasma miR-214-3p expressions showed a gradual decrease during the follow-up after treatment in NPC patients. Patients with recurrence or metastasis were always accompanied with higher levels of plasma miR-214-3p at the same time point. High pretreatment miR-214-3p expression (≥3.12) was significantly associated with NPC recurrence or metastasis by log-rank test using Kaplan-Meier survival curve analysis (P = 0.006).

CONCLUSIONS

Circulating miR-214-3p can serve as a noninvasive biomarker for the prediction of recurrence or metastasis in NPC patients.

Roles of Thyroid Hormone-Associated microRNAs Affecting Oxidative Stress in Human Hepatocellular Carcinoma

Oxidative stress occurs as a result of imbalance between the generation of reactive oxygen species (ROS) and antioxidant genes in cells, causing damage to lipids, proteins, and DNA. Accumulating damage of cellular components can trigger various diseases, including metabolic syndrome and cancer. Over the past few years, the physiological significance of microRNAs (miRNA) in cancer has been a focus of comprehensive research. In view of the extensive level of miRNA interference in biological processes, the roles of miRNAs in oxidative stress and their relevance in physiological processes have recently become a subject of interest. In-depth research is underway to specifically address the direct or indirect relationships of oxidative stress-induced miRNAs in liver cancer and the potential involvement of the thyroid hormone in these processes. While studies on thyroid hormone in liver cancer are abundantly documented, no conclusive information on the potential relationships among thyroid hormone, specific miRNAs, and oxidative stress in liver cancer is available. In this review, we discuss the effects of thyroid hormone on oxidative stress-related miRNAs that potentially have a positive or negative impact on liver cancer. Additionally, supporting evidence from clinical and animal experiments is provided.

Differential microRNA Expression in Porcine Endometrium Involved in Remodeling and Angiogenesis That Contributes to Embryonic Implantation

Background: In western swine breeds, up to 30% of embryonic losses occur during early pregnancy, and the majority of embryonic losses happens during implantation. In this period, maternal recognition of pregnancy begins to occur and blastocysts undergo dramatic morphologic changes. As with other species, changes in the uterine environment plays an important role in the process of embryo implantation in pigs. Erhualian (ER) pigs, one of the Chinese Taihu swine breeds, are known to have the highest litter size in the world. Experiments demonstrated that the greater embryonic survival on gestation day (GD) 12 in Chinese Taihu pigs is one important factor that contributes to enhanced litter size. This is largely controlled by maternal genes. In this study, endometrial samples were collected from pregnant Landrace×Large Yorkshire (LL) sows (parity 3) and ER sows (parity 3) on GD12 and the expression profiles of microRNAs (miRNAs) in the endometrium were compared between ER and LL using miRNA-seq technology. Results: A total of 288 miRNAs were identified in the pig endometrium, including 202 previously known and 86 novel miRNAs. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that highly abundant miRNAs might affect endometrial remodeling. Comparison between LL and ER sows revealed that 96 known miRNAs were differentially expressed between the two groups (including 78 up-regulated and 18 down-regulated miRNAs in ER compared to LL). Bioinformatics analysis showed that the target genes of some differentially expressed miRNAs were involved in pathways related to angiogenesis, proliferation, apoptosis, and tissue remodeling, which play critical roles in implantation by regulating endometrial structural changes and secretions of hormones, growth factors, and nutrients. Furthermore, the results demonstrated that insulin-like growth factor-1 protein expression was directly inhibited by miR-206. The lower expression of miR-206 in ER compared to LL might facilitate the angiogenesis of the endometrium during embryo implantation. Conclusions: The identified miRNAs that are differentially expressed in the endometrium of ER and LL pigs will contribute to the understanding of the role of miRNAs in embryonic implantation and the molecular mechanisms of the highest embryonic survival in Chinese ER pigs.

Inhibition of miR‑214 attenuates the migration and invasion of triple‑negative breast cancer cells

Triple‑negative breast cancer (TNBC) is a subtype of breast cancer. MicroRNA (miR)‑214 is closely associated with controlling the development of tumor cells; therefore, in the present study, the target gene and effects of miR‑214 on TNBC cells were explored. Luciferase activity was examined by luciferase reporter assay. The viability, invasion and migration of MDA‑MB‑231 TNBC cells were measured using Cell Counting kit‑8, Transwell and wound‑healing assays, respectively. The expression levels of various factors were determined using reverse transcription‑quantitative polymerase chain reaction and western blotting. The results demonstrated that the expression levels of miR‑214 were higher and the levels of α1‑antitrypsin (α1‑AT) were lower in TNBC tissues compared with in normal tissues. Subsequently, α1‑AT was revealed to be a target of miR‑214. Furthermore, inhibition of miR‑214 decreased cell viability, invasion and migration, enhanced the expression of E‑cadherin and tissue inhibitor of metalloproteinases‑2, and reduced the expression of metastatic tumour antigen 1 and matrix metalloproteinase‑2. Inhibition of miR‑214 also significantly downregulated the phosphorylation of protein kinase B (Akt) and mammalian target of rapamycin (mTOR), and markedly downregulated that of phosphoinositide 3‑kinase (PI3K); however, the expression levels of total PI3K, Akt and mTOR remained stable in all groups. Taken together, these findings indicated that α1‑AT may be a target of miR‑214. Downregulation of miR‑214 markedly suppressed the viability, migration and invasion of MDA‑MB‑231 cells, and inhibited the PI3K/Akt/mTOR pathway. These findings suggested that miR‑214 targeting α1‑AT may be a potential mechanism underlying TNBC development.

Global DNA methylation analysis reveals miR-214-3p contributes to cisplatin resistance in pediatric intracranial nongerminomatous malignant germ cell tumors

Background

Pediatric central nervous system germ cell tumors (CNSGCTs) are rare and heterogeneous neoplasms, which can be divided into germinomas and nongerminomatous germ cell tumors (NGGCTs). NGGCTs are further subdivided into mature teratomas and nongerminomatous malignant GCTs (NGMGCTs). Clinical outcomes suggest that NGMGCTs have poor prognosis and survival and that they require more extensive radiotherapy and adjuvant chemotherapy. However, the mechanisms underlying this difference are still unclear. DNA methylation alteration is generally acknowledged to cause therapeutic resistance in cancers. We hypothesized that the pediatric NGMGCTs exhibit a different genome-wide DNA methylation pattern, which is involved in the mechanism of its therapeutic resistance.

Methods

We performed methylation and hydroxymethylation DNA immunoprecipitation sequencing, mRNA expression microarray, and small RNA sequencing (smRNA-seq) to determine methylation-regulated genes, including microRNAs (miRNAs).

Results

The expression levels of 97 genes and 8 miRNAs were correlated with promoter DNA methylation and hydroxymethylation status, such as the miR-199/-214 cluster, and treatment with DNA demethylating agent 5-aza-2'-deoxycytidine elevated its expression level. Furthermore, smRNA-seq analysis showed 27 novel miRNA candidates with differential expression between germinomas and NGMGCTs. Overexpresssion of miR-214-3p in NCCIT cells leads to reduced expression of the pro-apoptotic protein BCL2-like 11 and induces cisplatin resistance.

Conclusions

We interrogated the differential DNA methylation patterns between germinomas and NGMGCTs and proposed a mechanism for chemoresistance in NGMGCTs. In addition, our sequencing data provide a roadmap for further pediatric CNSGCT research and potential targets for the development of new therapeutic strategies.

LncRNA CASC2 inhibits autophagy and promotes apoptosis in non-small cell lung cancer cells via regulating the miR-214/TRIM16 axis

Background: Dysregulated long noncoding RNAs (lncRNAs) have been frequently observed in various cancers including non-small cell lung cancer (NSCLC) and are closely associated with cancer progression. Previous studies also found that low expression of lncRNA cancer susceptibility candidate 2 (CASC2) functioned as a tumor suppressor in NSCLC. Our study aimed to explore the detailed molecular mechanism of CASC2 involved in NSCLC progression. Methods: The expressions of CASC2, tripartite motif-containing protein 16 (TRIM16) and miR-214 in NSCLC tissues and cells were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) or western blot. Flow cytometry analysis was performed to evaluate apoptosis. Autophagy was assessed using green fluorescent protein microtubule-associated protein 1 light chain 3α (GFP-LC3) puncta analysis, acridine orange (AO) staining and western blot. Luciferase reporter assay, RNA immunoprecipitation (RIP), RNA pull-down and immunofluorescence staining were employed to explore the association between CASC2, TRIM16 and miR-214. Results: CASC2 and TRIM16 expressions were significantly downregulated and miR-214 expression was dramatically upregulated in NSCLC tissues and cells. Overexpression of CASC2 induced apoptosis and inhibited autophagy in NSCLC cells. miR-214 was bound to CASC2 and its knockdown reversed the regulatory effect of CASC2 inhibition on apoptosis and autophagy in NSCLC cells. Moreover, TRIM16 was validated as a target of miR-214 and its interference attenuated miR-214 knockdown-mediated promotion of apoptosis and inhibition of autophagy. Besides, CASC2 enhanced TRIM16 expression through functioning as a competing endogenous RNA (ceRNA) for miR-214 in NSCLC cells. Conclusion: lncRNA CASC2 inhibited autophagy and promoted apoptosis in NSCLC cells via regulating the miR-214/TRIM16 axis, shedding light on the mechanism underlying NSCLC carcinogenesis.

The regulatory network of nasopharyngeal carcinoma metastasis with a focus on EBV, lncRNAs and miRNAs

Metastasis of nasopharyngeal carcinoma (NPC) remains a main cause of death for NPC patients even though great advances have been made in therapeutic approaches. An in-depth study into the molecular mechanisms of NPC metastasis will help us combat NPC. Epstein-Barr virus (EBV) infection is an evident feature of nonkeratinizing NPC and is strongly associated with tumor metastasis. Recently, long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have become a hot topic of research due to their epigenetic regulatory roles in NPC metastasis. The EBV products, lncRNAs and miRNAs can target each other and share several common signaling pathways, which form an interconnected, complex molecular regulatory network. In this review, we discuss the features of this regulatory network and summarize the molecular mechanisms of NPC metastasis, focusing on EBV, lncRNAs and miRNAs with updated knowledge.

The role of aberrant expression of T cell miRNAs affected by TNF-α in the immunopathogenesis of rheumatoid arthritis

Background

Tumor necrosis factor-alpha (TNF-α) can cause diverse T cell dysfunctions in patients with rheumatoid arthritis (RA). It is involved in the regulation of microRNAs (miRNAs) expression in different cell types. We hypothesized that the expression of T cell miRNAs would be affected by TNF-α, and these miRNAs could participate in the immunopathogenesis of RA.

Methods

Expression profiles of 270 human miRNAs in Jurkat cells, cultured in the presence or absence of TNF-α for 7 days were analyzed by real-time polymerase chain reaction. Potentially aberrantly expressed miRNAs were validated using T cell samples from 35 patients with RA and 15 controls. Transfection studies were conducted to search for gene expression and biological functions regulated by specific miRNAs.

Results

Initial analysis revealed 12 miRNAs were significantly lower, whereas the expression level of miR-146a was significantly higher in Jurkat cells after being cultured with TNF-α for 7 days. Decreased expression of miR-139-3p, miR-204, miR-760, miR-524-5p, miR-136, miR-548d-3p, miR-214, miR-383, and miR-887 were noted in RA T cells. Expression levels of miR-139-3p, miR-204, miR-214, and miR-760 were correlated with the use of biologic agents. The transfection of miR-214 mimic suppressed TNF-α-mediated apoptosis of Jurkat cells. Increased phosphorylation of extracellular regulating kinase (ERK) and c-Jun N-terminal kinase (JNK) was noted in RA T cells and Jurkat cells after TNF-α exposure. Transfection of Jurkat cells with miR-214 mimic suppressed both the basal and TNF-α-mediated ERK and JNK phosphoryation.

Conclusions

Among T cell miRNAs affected by TNF-α, the expression levels of nine miRNAs were decreased in T cells from patients with RA. The expression levels of miR-139-3p, miR-204, miR-214, and miR-760 increased in RA patients receiving biologic agents. The transfection of miR-214 reversed the TNF-α-mediated cells apoptosis and inhibited the phosphorylation of ERK and JNK in Jurkat cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-017-1465-z) contains supplementary material, which is available to authorized users.

Reciprocal regulation of miR-214 and PTEN by high glucose regulates renal glomerular mesangial and proximal tubular epithelial cell hypertrophy and matrix expansion

Aberrant expression of microRNAs (miRs) contributes to diabetic renal complications, including renal hypertrophy and matrix protein accumulation. Reduced expression of phosphatase and tensin homolog (PTEN) by hyperglycemia contributes to these processes. We considered involvement of miR in the downregulation of PTEN. In the renal cortex of type 1 diabetic mice, we detected increased expression of miR-214 in association with decreased levels of PTEN and enhanced Akt phosphorylation and fibronectin expression. Mesangial and proximal tubular epithelial cells exposed to high glucose showed augmented expression of miR-214. Mutagenesis studies using 3'-UTR of PTEN in a reporter construct revealed PTEN as a direct target of miR-214, which controls its expression in both of these cells. Overexpression of miR-214 decreased the levels of PTEN and increased Akt activity similar to high glucose and lead to phosphorylation of its substrates glycogen synthase kinase-3β, PRAS40, and tuberin. In contrast, quenching of miR-214 inhibited high-glucose-induced Akt activation and its substrate phosphorylation; these changes were reversed by small interfering RNAs against PTEN. Importantly, respective expression of miR-214 or anti-miR-214 increased or decreased the mammalian target of rapamycin complex 1 (mTORC1) activity induced by high glucose. Furthermore, mTORC1 activity was controlled by miR-214-targeted PTEN via Akt activation. In addition, neutralization of high-glucose-stimulated miR-214 expression significantly inhibited cell hypertrophy and expression of the matrix protein fibronectin. Finally, the anti-miR-214-induced inhibition of these processes was reversed by the expression of constitutively active Akt kinase and hyperactive mTORC1. These results uncover a significant role of miR-214 in the activation of mTORC1 that contributes to high-glucose-induced mesangial and proximal tubular cell hypertrophy and fibronectin expression.

Integrative analysis of the Pekin duck (Anas anas) MicroRNAome during feather follicle development

BACKGROUND

The quality and yield of duck feathers are very important economic traits that might be controlled by miRNA regulation. The aim of the present study was to investigate the mechanism underlying the crosstalk between individual miRNAs and the activity of signaling pathways that control the growth of duck feathers during different periods. We therefore conducted a comprehensive investigation using Solexa sequencing technology on the Pekin duck microRNAome over six stages of feather development at days 11, 15, and 20 of embryonic development (during the hatching period), and at 1 day and 4 and 10 weeks posthatch.

RESULTS

There were a total of 354 known miRNAs and 129 novel candidate miRNAs found based on comparisons with known miRNAs in the Gallus gallus miRBase. The series of miRNAs related to feather follicle formation as summarized in the present study showed two expression patterns, with primary follicle developed during embryonic stage and secondary follicle developed mainly at early post hatch stage. Analysis of miRNA expression profiles identified 18 highly expressed miRNAs, which might be directly responsible for regulation of feather development. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that in addition to Wnt and transforming growth factor (TGFβ) signaling pathways, which were widely reported in response to follicle formation, another group of signaling pathways that regulate lipid synthesis and metabolism, such as the phosphatidylinositol signaling system and glycerolipid metabolism and signaling, are also responsible for follicle formation.

CONCLUSION

The highly expressed miRNAs provide a valuable reference for further investigation into the functional miRNAs important for feather development. Lipid synthesis and metabolism related signaling pathways might be responsible for lipid formation on the surface of feather, and should be paid much more attention for their relation to feather quality.

MicroRNA-153 regulated AKT1 expression and suppressed cell proliferation of epithelial ovarian cancer cells

Epithelial ovarian cancer (EOC) is the most fatal malignancies in females worldwide, with increasing incidence recently in China. MiR-153 was reported to be dysregulated in some human cancers, including EOC. In this study, we explored the roles of miR-153 and its target AKT1 in regulating growth and migration in EOC. Cell proliferation was measured with a CCK-8 assay. Real-time quantitative RT-PCR was performed to investigate expression levels of miR-153. Cell cycle features were analyzed by Flow cytometry system. The direct target gene was confirmed by dual-luciferase reporter assay. We found the expression levels of miR-153 were generally lower in the EOC tissues than in the matched normal tissues. The miR-153 mimics caused significant G0/G1 arrest in A2780 cells. Overexpression of miR-153 suppressed cell proliferation and migration in ovarian cancer. Results of dual-luciferase reporter assay suggested that AKT1 was a direct target of miR-153 in ovarian cancer cells. Overexpression of AKT1 reverses the inhibition effect of miR-153 on cell proliferation. Introduction of miR-153 into EOC cell lines leaded to inhibition of cell proliferation and migration by directly targeting AKT1. MiR-153 may have prognostic or therapeutic value for the future management of ovarian cancer patients.

MicroRNA-214 regulates immunity-related genes in bovine mammary epithelial cells by targeting NFATc3 and TRAF3

In human, microRNA-214 (miR-214) plays crucial roles in mechanisms of immunity. However, the potential importance of miR-214 in immune mechanisms in dairy cows has not been investigated. In this study, we assessed potential immunity-related functions of miR-214 in human 293A cells and in bovine mammary epithelial cells (BMECs). We found that NFATc3 and TRAF3 could be targeted by miR-214 in both 293A cells and BMECs. We also found that miR-214 indirectly inhibited the expression of MAP3K14, TBK1 and inflammatory cytokines IL-6 and IL-1β. Taken together, our data revealed miR-214 regulated immunity-related genes by targeting NFATc3 and TRAF3, which provides insight into the molecular basis of immunity.

Circulating microRNA-214 and -126 as potential biomarkers for canine neoplastic disease

Circulating microRNAs in the blood may provide diagnostic and prognostic information about canine neoplastic diseases, and their profiles may be conserved between human and canine species. We performed RT-qPCR to obtain the profiles of circulating plasma microRNA-214 and -126 in total 181 cases of canine neoplastic diseases and healthy controls. MicroRNA-214 levels were high in 2 epithelial tumours (thyroid and mammary carcinomas) and 4 non-epithelial tumours (osteosarcoma, histiocytic sarcoma, chondrosarcoma, and hemangiosarcoma). In contrast, microRNA-126 levels were high in 6 epithelial tumours (mammary, hepatocellular, squamous cell, thyroid, transitional cell carcinomas, and adenocarcinoma) and 4 non-epithelial tumours (osteosarcoma, mast cell tumour, melanoma, and hemangiosarcoma). The diagnostic potential of microRNA-214 was relatively high in sarcomas, whereas that of microR-126 was high in most types of the tumours. MicroRNA-214 and -126 were prognostic predictors in 2 groups (adenocarcinoma and non-epithelial tumours except for osteosarcoma) and 3 groups (epithelial tumours, adenocarcinoma, and melanoma), respectively. Additionally, the microRNA levels did not show a strong correlation with the other clinical parameters. In conclusion, circulating microRNA-214 and -126 have the potential to be diagnostic and prognostic biomarkers for canine neoplastic diseases. Furthermore, their profiles may be key references as well for exploring novel biomarkers for human cancers.

miR-185-3p regulates the invasion and metastasis of nasopharyngeal carcinoma by targeting WNT2B in vitro

MicroRNAs (miRs) have been recognised as important regulators of malignant behaviour in different types of human cancer, including nasopharyngeal carcinoma (NPC). A previous study by our group revealed that miR-185-3p regulates the radioresistance of NPC cells. The present study aimed to investigate the effect of miR-185-3p on NPC invasion and metastasis. Human NPC CNE-2 and 5-8F cell lines were transfected with a miR-185-3p mimic and miR-185-3p inhibitor, respectively, and their effects on the invasion and metastasis of these cells was assessed using a wound healing assay and Matrigel invasion assay. The target gene of miR-185-3p, Wnt family member 2B (WNT2B) was silenced in 5-8F cells using siRNA in order to investigate its function in NPC. Data from the present study demonstrated that the expression of miR-185-3p was the highest in 5-8F and lowest in CNE-2 cells out of a range of NPC cell lines. Following the transfection of miR-185-3p mimic into CNE-2 cells, the wound healing and Matrigel invasion assays indicated that the migration and invasion ability of CNE-2 cells was significantly reduced compared with the negative control group. In addition, the inhibition of miR-185-3p in 5-8F cells significantly increased the capacity for migration and invasion. Furthermore, silencing WNT2B expression resulted in a significant reduction in the invasion and metastasis in 5-8F cells. The inhibition of miR-185-3p, which promotes invasion and metastasis, could be reversed through the silencing of WNT2B in 5-8F cells. The results of the present study indicate that miR-185-3p mediates the invasion and metastasis of NPC by targeting WNT2B in vitro.

Downregulated expression of miRNA-149 promotes apoptosis in side population cells sorted from the TSU prostate cancer cell line

The objective of the present study was to identify prostate cancer stem cells and determine the effects of modulating specific miRNAs on prostate CSC proliferation and apoptosis. We applied flow cytometry sorting of side population cells to cultures of prostate cancer cell lines (TSU, DU145, PC-3 and LNCaP). The proportion of SP cells in the TSU line was 1.60±0.40% (mean ± SD), while that of the DU145, PC-3 and LNCaP lines was 0.60±0.05, 0.80±0.05 and 0.60±0.20%, respectively. Because the proportion of SP cells derived from TSU cells is greater, these cells were selected to sort side population cells and non-side population cells. The stem-like properties of SP cells had been identified by in vivo and in vitro experiments, and the related study was published. RNA was extracted from the SP cells and non-SP cells and analyzed using miRNA microarray technology. Fifty-three miRNAs with significant differences in their expression were detected in total. Furthermore, 20 of these miRNAs were validated by qPCR. We found that hsa-miR‑149 expression in SP cells and non-SP cells was significantly different; hsa-miR-149 was significantly upregulated in SP cells. By constructing a vector for lentiviral infection, we found that the downregulation of hsa-miR-149 leads to a reduction in proliferation, an increase in apoptosis, and a significant reduction in the colony formation potential, thus, inhibiting tumor growth in vivo of SP cells from the TSU cell line. The present study will provide new avenues toward understanding the function of prostate cancer stem cells (PCSCs) in tumorigenicity and metastasis.

Distinctive microRNA expression in early stage nasopharyngeal carcinoma patients

The goal of this study was to investigate microRNAs (miRs) expression at different stages of nasopharyngeal carcinoma (NPC). MiR expression profiling at various stages of NPC was performed by miR array and further verified using quantitative real-time RT-PCR. Pathway enrichment analysis was carried out to identify the functional pathways regulated by the miRs. The expression of a selected group of identified miRs was verified in stage I NPC by in situ hybridization (ISH). A total of 449 miRs were identified with significantly different expressions between NPC tissues and normal pharyngeal tissues. Eighty-four miRs were dysregulated only in stage I NPC, among which 45 miRs were up-regulated and the other 39 were down-regulated. Pathway enrichment assay revleaed that three significantly down-regulated and three significantly up-regulated miRs involved in 12 pathways associating with tumour formation and progression. Quantitative RT-PCR confirmed the miR array result. In addition, the low expression levels of hsa-miR-4324, hsa-miR-203a and hsa-miR-199b-5p were further validated in stage I NPC by ISH. This present study identifed the miR signature in stage I NPC, providing the basis for early detection and treatment of NPC.

MicroRNAs as novel therapeutic targets to treat kidney injury and fibrosis

MicroRNAs (miRs), a class of small noncoding RNAs that act as post-transcriptional regulators of gene expression, have attracted increasing attention as critical regulators of organogenesis, cancer, and disease. Interest has been spurred by development of a novel class of synthetic RNA oligonucleotides with excellent drug-like properties that hybridize to a specific miR, preventing its action. In kidney disease, a small number of miRs are dysregulated. These overlap with regulated miRs in nephrogenesis and kidney cancers. Several dysregulated miRs have been identified in fibrotic diseases of other organs, representing a "fibrotic signature," and some of these fibrotic miRs contribute remarkably to the pathogenesis of kidney disease. Chronic kidney disease, affecting ∼10% of the population, leads to kidney failure, with few treatment options. Here, we will explore the pathological mechanism of miR-21, whose pre-eminent role in amplifying kidney disease and fibrosis by suppressing mitochondrial biogenesis and function is established. Evolving roles for miR-214, -199, -200, -155, -29, -223, and -126 in kidney disease will be discussed, and we will demonstrate how studying functions of distinct miRs has led to new mechanistic insights for kidney disease progression. Finally, the utility of anti-miR oligonucleotides as potential novel therapeutics to treat chronic disease will be highlighted.

Identification of TLR2 and TLR4‑induced microRNAs in human mesenchymal stem cells and their possible roles in regulating TLR signals

Toll-like receptors (TLRs) are expressed in human bone marrow-derived mesenchymal stromal cells (BM-MSCs), and the activation of TLRs is important in proliferation, differentiation, migration and hematopoiesis-supporting functions of BM-MSCs. However, the molecular mechanisms underlying these processes remain to be elucidated. MicroRNAs (miRNAs) are involved in various biological functions by mediating mRNA degradation or inhibiting translation of target genes. The present study aimed to identify whether TLRs regulate the expression of miRNAs in BM-MSCs and elucidate the regulatory roles of miRNAs. Illumina high-throughput sequencing was used to profile miRNAs expressed in BM-MSCs stimulated with TLR2 agonist, PAM₃CSK4 (PM) or TLR4 agonist, lipopolysaccharides (LPS). A marked expression change upon PM or LPS treatment was observed for 164 known miRNAs and six novel miRNAs that were identified. The expression of six novel miRNAs and 40 randomly selected known miRNAs was further validated by reverse transcription-quantitative polymerase chain reaction. In addition, bioinformatic methods were used to predict the potential target genes of the abundant known miRNAs. The gene ontology analysis demonstrated that predicted targets were enriched in the regulation of signal transduction, cellular processes and macromolecule metabolic processes. Kyoto Encyclopedia of Genes and Genomes pathway analysis suggested that these potential targets were involved in numerous important pathways, predominantly including mitogen-activated protein kinase, phosphati-dylinositol-4,5-bisphosphate 3-kinase-Akt, neurotrophin and cancer-associated signaling pathways. The present study aimed to identify the global expression change of miRNAs in BM-MSCs stimulated with LPS and PM, providing the opportunity to further elucidate the roles of miRNAs in mediating TLR signals to regulate the functions of BM-MSCs.

GALNT7, a target of miR-494, participates in the oncogenesis of nasopharyngeal carcinoma

GalNAc-transferase-7 (GALNT7) is essential for the regulation of cell proliferation and has been implicated in tumorigenesis. However, the role of GALNT7 in the development and progression of nasopharyngeal carcinoma (NPC) remains unclear. Our previous study showed that GALNT7 was a putative target of miR-494, which was confirmed by luciferase reporter assay. In the present study, we demonstrated that in vitro knockdown of GALNT7 significantly inhibited the proliferation, colony formation, migration, and invasion of NPC-derived cells. In vivo tumorigenicity assay showed that miR-494 and GALNT7-small interfering RNA (siRNA) reduced tumor growth in nude mice. Taken together, our results provided new evidence for an oncogenic role of GALNT7 in NPC.

miR-133b, a microRNA targeting S1PR1, suppresses nasopharyngeal carcinoma cell proliferation

MicroRNAs (miRs) are a class of short and non-coding RNA molecules, which function as either oncogenes or tumor suppressors in the development of various human cancers, including nasopharyngeal carcinoma (NPC). The aim of the present study was to investigate the expression of miR-133b in NPC tissue samples, as compared with adjacent normal tissues, and to examine its roles and underlying mechanisms. Analysis using reverse transcription-quantitative polymerase chain reaction demonstrated that miR-133b was downregulated in NPC tissue samples, as compared with adjacent tissues. In vitro experiments using NPC cell lines transfected with miR-133b mimics or antisense oligonucleotides further demonstrated that the overexpression of miR-133b mimics impaired, whereas knockdown of its expression promoted, the proliferation of NPC cells. Sphingosine-1-phosphate receptor 1 (S1PR1) was predicted to be a target of miR-133b. Luciferase reporter assays showed that miR-133b inhibited the protein expression of S1PR1 by targeting its 3'-untranslated region. Furthermore, western blot analysis demonstrated that miR-133B altered the regulation of the signal transducer and activator of transcription-3 (STAT3) signaling pathway and the expression of downstream proteins in NPC cells. Therefore, the results of the present study suggested that a previously unknown miR-133b/S1PR1 molecular network may regulate NPC progression.

MicroRNA Regulation of Human Breast Cancer Stem Cells

MicroRNAs (miRNAs) are involved in virtually all biological processes, including stem cell maintenance, differentiation, and development. The dysregulation of miRNAs is associated with many human diseases including cancer. We have identified a set of miRNAs differentially expressed between human breast cancer stem cells (CSCs) and non-tumorigenic cancer cells. In addition, these miRNAs are similarly upregulated or downregulated in normal mammary stem/progenitor cells. In this review, we mainly describe the miRNAs that are dysregulated in human breast CSCs directly isolated from clinical specimens. The miRNAs and their clusters, such as the miR-200 clusters, miR-183 cluster, miR-221-222 cluster, let-7, miR-142 and miR-214, target the genes and pathways important for stem cell maintenance, such as the self-renewal gene BMI1, apoptosis, Wnt signaling, Notch signaling, and epithelial-to-mesenchymal transition. In addition, the current evidence shows that metastatic breast CSCs acquire a phenotype that is different from the CSCs in a primary site. Thus, clarifying the miRNA regulation of the metastatic breast CSCs will further advance our understanding of the roles of human breast CSCs in tumor progression.

miR-27a regulates the sensitivity of breast cancer cells to cisplatin treatment via BAK-SMAC/DIABLO-XIAP axis

MicroRNA-27a (miR-27a) has been reported to be an onco-microRNA in multiple cancers promoting tumor growth and metastasis, but the role of miR-27a in regulating the cancer sensitivity to chemotherapy remains unknown. In this study, upregulation of miR-27a was validated by real-time PCR analysis in breast cancer (BC) cell lines and samples of BC patients. A negative correlation between miR-27a and bak was also observed in normal breast epithelial cell line MCF-10A and BC cell lines, suggesting that the bak is the potential target of miR-27a. miR-27a could modulate the growth and metastasis of BC cells. More importantly, we found that knockdown of miR-27a by the specific inhibitors significantly increased the sensitivity of T-47D cells to cisplatin (CDDP) treatment. After further investigation, we indicated that the knockdown of miR-27a promoted the apoptosis via mitochondrial pathway in T-47D cells treated with CDDP, depending on the BAK-second mitochondria-derived activator of caspase/direct IAP binding protein with low pI (SMAC/DIABLO)-X-linked inhibitor of apoptosis (XIAP) axis. Interestingly, we found that the sensitivity of T-47D cells to some other chemotherapeutic agents (5-fluorouracil, doxorubicin, and tumor necrosis factor-related apoptosis-inducing ligand) was also regulated by miR-27a. These findings improve our understanding of the role of miR-27a in breast cancer and might provide a novel strategy for cancer therapy.

miRNA-214: Expression, Therapeutic and Diagnostic Potential in Cancer

MicroRNAs (miRNAs) are small noncoding RNAs that negatively regulate gene expression by binding to the 3' untranslated region of their target mRNAs. Recent work supports a role for miRNAs in the initiation and progression of human cancer. miRNA-214 not only mediates differentiation, senescence, angiogenesis, cell migration and virus replication but also acts as a tumor suppressor gene and oncogene. Increasing evidence indicates that miRNA-214 may serve as a biomarker in some cancer types. The aim of this review is to highlight and clarify the complexity of miRNA-214 activity, emphasizing its significant therapeutic and diagnostic potential.

miR-214-mediated downregulation of RNF8 induces chromosomal instability in ovarian cancer cells

Defective DNA damage response (DDR) is frequently associated with carcinogenesis. Abrogation of DDR leads to chromosomal instability, a most common characteristic of tumors. However, the molecular mechanisms underlying regulation of DDR are still elusive. The ubiquitin ligase RNF8 mediates the ubiquitination of γH2AX and recruits 53BP1 and BRCA1 to DNA damage sites which promotes DDR and inhibits chromosomal instability. Though RNF8 is a key player involved in DDR, regulation of its expression is still poorly understood. Here, we show that miR-214 could abrogate DDR by repressing RNF8 expression through direct binding to 3'-untranslated region (3' UTR) of RNF8 mRNA in human ovarian cancer cells. Antagonizing miR-214 by expressing its inhibitors in A2780 cells significantly increased RNF8 expression and thus promoted DNA damage repair. Consistent with the role of miR-214 in regulating RNF8 expression, the impaired DNA repair induced by miR-214 overexpression can be rescued by overexpressing RNF8 mRNA lacking the 3' UTR. Together, our results indicate that down-regulation of RNF8 mediated by miR-214 impedes DNA damage response to induce chromosomal instability in ovarian cancers, which may facilitate the understanding of mechanisms underlying chromosomal instability.

Functional elucidation of miR-494 in the tumorigenesis of nasopharyngeal carcinoma

Nasopharyngeal carcinoma has very high incidence and high mortality worldwide. MiRNA is related to the tumorigenesis and metastasis of a variety of tumors. In the present study, we verify that the expression of miR-494 in NPC tissues and NPC-derived cells was down-regulated, respectively. The proliferation, colony formation, migration, and invasion of NPC-derived cells were suppressed, while the cell apoptosis was promoted, when miR-494 was over-expressed in these cells. GALNT7 and CDK16 were confirmed to be the direct targets of miR-494. These results suggested that miR-494 play an inhibitory role in the tumorigenesis of NPC.

Small molecules targeting microRNA for cancer therapy: Promises and obstacles

Aberrant expression of miRNAs is critically implicated in cancer initiation and progression. Therapeutic approaches focused on regulating miRNAs are therefore a promising approach for treating cancer. Antisense oligonucleotides, miRNA sponges, and CRISPR/Cas9 genome editing systems are being investigated as tools for regulating miRNAs. Despite the accruing insights in the use of these tools, delivery concerns have mitigated clinical application of such systems. In contrast, little attention has been given to the potential of small molecules to modulate miRNA expression for cancer therapy. In these years, many researches proved that small molecules targeting cancer-related miRNAs might have greater potential for cancer treatment. Small molecules targeting cancer related miRNAs showed significantly promising results in different cancer models. However, there are still several obstacles hindering the progress and clinical application in this area. This review discusses the development, mechanisms and application of small molecules for modulating oncogenic miRNAs (oncomiRs). Attention has also been given to screening technologies and perspectives aimed to facilitate clinical translation for small molecule-based miRNA therapeutics.

Overexpression of miR-214-3p in esophageal squamous cancer cells enhances sensitivity to cisplatin by targeting survivin directly and indirectly through CUG-BP1

Based on its marked overexpression in multiple malignancies and its roles in promoting cell survival and proliferation, survivin is an attractive candidate for targeted therapy. Towards this end, a detailed understanding of the mechanisms regulating survivin expression in different cancer cells will be critical. We have previously shown that the RNA-binding protein (RBP) CUG-BP1 is overexpressed in esophageal cancer cells and post-transcriptionally regulates survivin in these cells. The objective of this study was to investigate the role of microRNAs (miRs) in regulating survivin expression in esophageal cancer cells. Using miR expression profiling analysis, we found that miR-214-3p is one of the most markedly downregulated miRs in two esophageal squamous cancer cell lines compared to esophageal epithelial cells. Interestingly, using miR target prediction programs, both survivin and CUG-BP1 mRNA were found to contain potential binding sites for miR-214-3p. Forced expression of miR-214-3p in esophageal cancer cells leads to a decrease in the mRNA and protein levels of both survivin and CUG-BP1. This effect is due to decreased mRNA stability of both targets. By contrast, silencing miR-214-3p in esophageal epithelial cells leads to an increase in both survivin and CUG-BP1 mRNA and protein. To determine whether the observed effect of miR-214-3p on survivin expression was direct, mediated through CUG-BP1, or both, binding studies utilizing biotin pull-down assays and heterologous luciferase reporter constructs were performed. These demonstrated that the mRNA of survivin and CUG-BP1 each contain two functional miR-214-3p binding sites as confirmed by mutational analysis. Finally, forced expression of miR-214-3p enhances the sensitivity of esophageal cancer cells to Cisplatin-induced apoptosis. This effect is abrogated with rescue expression of survivin or CUG-BP1. These findings suggest that miR-214-3p acts as a tumor suppressor and that its downregulation contributes to chemoresistance in esophageal cancer cells by targeting both survivin and CUG-BP1.

Mir-192 suppresses apoptosis and promotes proliferation in esophageal aquamous cell caicinoma by targeting Bim

MicroRNAs (miRNAs) are small, non-coding RNAs of endogenous origin. Accumulating studies have shown aberrant miRNA expression plays an important role in many tumor types. However, the mechanisms by which miRNAs regulate esophageal squamous cell carcinoma (ESCC) development remain poorly understood. In the present study, we assayed expression level of miR-192 in ESCC tissues and cell lines by real-time PCR, and defined the target gene and biological function by luciferase reporter assay, Western blot and apoptosis assay. We first verified that the expression level of miR-192 was significantly increased in ESCC tissues and cancer cells. Moreover, miR-192 over-expression inhibited cells apoptosis and promoted ESCC cells proliferation. We further demonstrated that miR-192 directly targeted 3'-UTR of Bim gene, and inhibited its protein expression. Importantly, Bim could reduce ESCC cells apoptosis ability induced by miR-192. These data suggest an important role of miR-192 in the molecular etiology of ESCC and implicate the potential application of miR-192 in ESCC therapy.

Murine MicroRNA-214 regulates intracellular adhesion molecule (ICAM1) gene expression in genital Chlamydia muridarum infection

The hallmark of chlamydial infection is the development of upper genital pathology in the form of hydrosalpinx and oviduct and/or tubal dilatation. Although molecular events leading to genital tissue presentation and cellular architectural remodelling are unclear, early-stage host immune responses are believed to contribute to these long-term sequelae. Recently, we reported the contribution of selected infection-associated microRNAs (miRs) in the generation of host immunity at early-stage infection (day 6 after intravaginal Chlamydia muridarum challenge in C57BL/6 mice). In this report, we describe the contribution of an infection-associated microRNA, i.e. miR-214, to host immunity. Chlamydia muridarum infection in the C57BL/6 mouse genital tract significantly down-regulated miR-214 while up-regulating intracellular adhesion molecule 1 (ICAM1) gene expression. These in vivo observations were confirmed by establishing direct regulation of ICAM-1 by miR-214 in ex vivo genital cell cultures in the presence of miR-214 mimic and inhibitor. Because, ICAM-1 contributes to recruitment of neutrophils following infection, we also demonstrated that alteration of ICAM1 by miR-214 in interleukin-17A-deficient (IL-17A(-/-) ) mice correlated with reduction of neutrophils infiltrating genital tissue at day 6 after challenge. Additionally, these early-stage events resulted in significantly decreased genital pathology in IL-17A(-/-) mice compared with C57BL/6 mice. This report provides evidence for early-stage regulation of ICAM1 by microRNAs, resulting in reduction of genital pathology associated with chlamydial infection.

MiRNA-based therapeutic intervention of cancer

MicroRNAs (miRNAs) are important modulators of eukaryotic gene expression. By targeting protein coding transcripts, miRNAs influence the cellular transcriptome and proteome, thus helping to determine cell fate. MiRNAs have emerged as crucial molecules in cancer research, in which recent studies have linked erratic expression of miRNAs to carcinogenesis and have provided solid evidence for their potential in cancer therapy. This review briefly summarises the recent knowledge on the involvement of miRNAs in tumourigenesis and reviews current studies on the therapeutic strategies and advances in the delivery of miRNAs.

Effects and mechanism of miR-214 on hepatocellular carcinoma

OBJECTIVE

To explore the role of miR-214 in the progression of hepatocellular carcinoma (HCC) and its inhibitory mechanisms in depressing the signaling pathway of β-catenin, this study was conducted.

METHODS

We ectopically expressed miR-214 in HepG2 cells to obtain cell lines Lv-miR-214-HepG2 and their control Lv-control-HepG2. Differences between the two cell lines were compared in cell growth, proliferation, colony forming ability and cell cycles. RT-PCR method was applied for the quantification of β-catenin mRNA expression. Western-blot method was applied for the determination of the protein level of β-catenin and their downstream targets (ie. Cyclin D1, c-Myc and TCF-1). The effect of miR-214 on cells was further explored through RNA interference and restoring miR-214 expression.

RESULTS

In comparison with negative (Lv-control-HepG2) and blank (HepG2) control, a significant inhibition of cell growth and proliferation caused by miR-214 was observed after 48∼72h of cell culture experiments (P<0.05). The miR-214 treatment resulted in a colony forming efficiency of (23.28±3.26)%, which was significantly lower than that of negative control [(51.31±3.97)%] (P<0.05). According to FCM results, the experimental group, compared with control, showed a higher proportion of cells in G0/G1 phase [(70.32±3.12)%] but a lower proportion in S phase [(18.42±2.90)%] (P<0.05). The MTT assay demonstrated a significant inhibition of the proliferation and β-catenin expression of HCC cells compared with control (P<0.05), while no significant difference was observed after HCC cells being transfected with β-catenin overexpression plasmid (P>0.05). By comparing to the RT-PCR and Western-blot results of control, the miR-214 treatment led to a slightly decrease in the β-catenin mRNA expression (P>0.05), but an extremely inhibition in the protein level of β-catenin and its downstream targets Cyclin D1, c-Myc, and TCF-1 (P<0.05).

CONCLUSIONS

miR-214 functions as a suppressor during the progression of HCC, and its inhibitory role was achieved by down-regulating β-catenin signaling pathway.

Cantharidin inhibits cell proliferation and promotes apoptosis in tongue squamous cell carcinoma through suppression of miR-214 and regulation of p53 and Bcl-2/Bax

Cantharidin, a type of terpenoid, is a chemical compount secreted by the blister beetle or Mylabris phelarata pallas of the Meloidae family. Cantharidin is known to have good antitumor activity. The present study aimed to investigate the anticancer effect of cantharidin and its possible underlying mechanism using tongue squamous cell carcinoma (TSCC) TCA8113 cells. TCA8113 cells were treated with various concentrations of cantharidin, and the cell viability and cytotoxicity were assessed using MTT and LDH assays, respectively. Flow cytometry was conducted to examine cell apoptosis and colorimetric protease assay was performed to analyze caspase-9/3 activities in TCA8113 cells. qPCR and western blot analysis were used to investigate microRNA-214 (miR-214) expression, as well as the expression of p53, Bcl-2 and Bax proteins in TCA8113 cells. miR-214 and anti-miR-214 were transfected with mimics to examine whether miR-214 expression regulated the anticancer effect of cantharidin on TCA8113 cells and p53, Bcl-2 and Bax protein expression. The anticancer effect of cantharidin significantly inhibited cell proliferation and increased cytotoxicity of TSCC Tca8113 cells in a dose- and time-dependent manner. In addition, cantharidin induced cell apoptosis and activated caspase-9/3 activities of TSCC Tca8113 cells. Cantharidin markedly weakened miR-214 expression level, activated p53 protein expression, and suppressed the Bcl-2/Bax signaling pathway in Tca8113 cells. Downregulation of miR-214 increased p53 protein expression and decreased the Bcl-2/Bax signaling pathway of TSCC Tca8113 cells. However, the overexpression of miR-214 reduced the anticancer effect of cantharidin on the proliferation and apoptosis of TSCC Tca8113 cells, inhibited p53 protein expression, and increased the Bcl-2/Bax signaling pathway. The results suggested that cantharidin is a potential anticancer drug that can be used to regulate the proliferation and apoptosis of human TSCC Tca8113 cells. Additionally, its mechanism may partially be associated with the downregulation of miR-214, upregulation of p53 protein expression and suppression of the Bcl-2/Bax signaling pathway.

miR-214 as a key hub that controls cancer networks: small player, multiple functions

MicroRNAs are short regulatory RNAs that are able to post-transcriptionally modulate gene expression and that have crucial roles in the control of physiological and pathological processes including cancer onset, growth, and progression. miR-214, located inside the sequence of the long noncoding Dmn3os transcript, contributes to the regulation of normal and cancer cell biology, even if it operates in a context-dependent and sometimes contradictory manner. miR-214 is deregulated in several human tumors including melanoma, breast, ovarian, gastric, and hepatocellular carcinomas. miR-214's pleiotropic and tumor-specific contribution to various cancer formation and progression hallmarks is achieved via its several target genes. In fact, miR-214 behaves as a key hub by coordinating fundamental signaling networks such as PTEN/AKT, β-catenin, and tyrosine kinase receptor pathways. Interestingly, miR-214 also regulates the levels of crucial gene expression modulators: the epigenetic repressor Ezh2, "genome guardian" p53, transcription factors TFAP2, and another microRNA, miR-148b. Thus, miR-214 seems to have essential roles in coordinating tumor proliferation, stemness, angiogenesis, invasiveness, extravasation, metastasis, resistance to chemotherapy, and microenvironment. The sum of current literature reports suggests that miR-214 is a molecular hub involved in the control of cancer networks and, as such, could be a potential diagnostic/prognostic biomarker and target for therapeutic intervention.

The role of microRNAs in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC), a distinct type of head and neck cancer, is prevalent in Southeast Asia and southern China. Ethnic background and environmental factors contribute to the development of NPC, further complicating its pathogenesis. An increasing body of evidence indicates that microRNAs (miRNAs) play an important role in the development and progression of NPC, in particular, 32 miRNAs are involved in NPC tumorigenesis, progression, and metastasis. The causal involvement of miRNAs in NPC and their possible use as biomarkers have been extensively studied with promising results, demonstrating the diagnostic and therapeutic potential of miRNAs in NPC. In this review, we summarize the role of all the known miRNAs involved in the signaling pathway implicated in NPC.

Antisense therapeutics in oncology: current status

There is increasing progress in translational oncology and tremendous breakthroughs have been made as evidenced by preclinical and clinical trials. Data obtained from high-throughput technologies are deepening our understanding about the molecular and gene network in cancer cells and rapidly emerging in vitro and in vivo evidence is highlighting the role of antisense agents as specific inhibitors of the expression of target genes, thus modulating the response of cancer cells to different therapeutic strategies. Much information is continuously being added into various facets of molecular oncology and it is now understood that overexpression of antiapoptotic proteins, oncogenes, oncogenic microRNAs (miRNA), and fusion proteins make cancer cells difficult to target. Delivery of antisense oligonucleotides has remained a challenge and technological developments have helped in overcoming hurdles by improving the ability to penetrate cells, effective and targeted binding to gene sequences, and downregulation of target gene function. Different delivery systems, including stable nucleic acid lipid particles, have shown potential in enhancing the delivery of cargo to the target site. In this review, we attempt to summarize the current progress in the development of antisense therapeutics and their potential in medical research. We partition this multicomponent review into introductory aspects about recent breakthroughs in antisense therapeutics. We also discuss how antisense therapeutics have shown potential in resensitizing resistant cancer cells to apoptosis by targeted inhibition of antiapoptotic proteins, oncogenic miRNAs, and BCR-ABL.

Cardio-miRNAs and onco-miRNAs: circulating miRNA-based diagnostics for non-cancerous and cancerous diseases

Cardiovascular diseases and cancers are the leading causes of morbidity and mortality in the world. MicroRNAs (miRNAs) are short non-coding RNAs that primarily repress target mRNAs. Here, miR-24, miR-125b, miR-195, and miR-214 were selected as representative cardio-miRs that are upregulated in human heart failure. To bridge the gap between miRNA studies in cardiology and oncology, the targets and functions of these miRNAs in cardiovascular diseases and cancers will be reviewed. ACVR1B, BCL2, BIM, eNOS, FGFR3, JPH2, MEN1, MYC, p16, and ST7L are miR-24 targets that have been experimentally validated in human cells. ARID3B, BAK1, BCL2, BMPR1B, ERBB2, FGFR2, IL6R, MUC1, SITR7, Smoothened, STAT3, TET2, and TP53 are representative miR-125b targets. ACVR2A, BCL2, CCND1, E2F3, GLUT3, MYB, RAF1, VEGF, WEE1, and WNT7A are representative miR-195 targets. BCL2L2, ß-catenin, BIM, CADM1, EZH2, FGFR1, NRAS, PTEN, TP53, and TWIST1 are representative miR-214 targets. miR-125b is a good cardio-miR that protects cardiomyocytes; miR-195 is a bad cardio-miR that elicits cardiomyopathy and heart failure; miR-24 and miR-214 are bi-functional cardio-miRs. By contrast, miR-24, miR-125b, miR-195, and miR-214 function as oncogenic or tumor suppressor miRNAs in a cancer (sub)type-dependent manner. Circulating miR-24 is elevated in diabetes, breast cancer and lung cancer. Circulating miR-195 is elevated in acute myocardial infarction, breast cancer, prostate cancer and colorectal adenoma. Circulating miR-125b and miR-214 are elevated in some cancers. Cardio-miRs and onco-miRs bear some similarities in functions and circulation profiles. miRNAs regulate WNT, FGF, Hedgehog and other signaling cascades that are involved in orchestration of embryogenesis and homeostasis as well as pathogenesis of human diseases. Because circulating miRNA profiles are modulated by genetic and environmental factors and are dysregulated by genetic and epigenetic alterations in somatic cells, circulating miRNA association studies (CMASs) within several thousands of cases each for common non-cancerous diseases and major cancers are necessary for miRNA-based diagnostics.

MicroRNA-214 regulates osteosarcoma survival and growth by directly targeting phosphatase and tensin homolog

An increasing number of microRNAs (miRNAs) have been identified as diagnostic and prognostic biomarkers, as well as additional therapeutic tools, in skeletal diseases. Recent studies have established the pathophysiological role of miR‑214, using human osteoporotic bone specimens. However, miR‑214 expression levels and the underlying regulatory mechanism in human osteosarcoma remain unclear. Quantitative polymerase chain reaction (qPCR) was used to examine the expression of miR‑214 in human osteosarcoma tissues and cells. Transfection of the cells with either a miR‑214 expressing‑plasmid, mimic or inhibitor was performed, in order to investigate the role of miR‑214 in osteosarcoma. In this study, miR‑214 was shown to be significantly increased in the majority of 15 examined osteosarcoma tissues and in the Saos‑2 human osteosarcoma cell line. Overexpression of miR‑214 in Saos‑2 cells induced cell proliferation, while inhibition of miR‑214 promoted Saos‑2 cell apoptosis in vitro. Furthermore, ectopic expression of miR‑214 markedly promoted osteosarcoma development in a subcutaneous xenotransplantation model in BALB/c athymic nude mice. The role of miR‑214 in osteocarcinogenesis was further investigated and phosphatase and tensin homolog (PTEN) was determined to be a direct target of miR‑214 in Saos‑2 cells. The proliferation‑promoting effect of PTEN knockdown was similar to that of miR‑214 overexpression. This study revealed that miR‑214 exerted a crucial role in promoting osteosarcoma progression and this suggests that modulation of miR‑214 levels may provide a novel therapeutic approach in cancer treatment.