MiR-186-5p upregulation inhibits proliferation, metastasis and epithelial-to-mesenchymal transition of colorectal cancer cell by targeting ZEB1

MiR-186 represses progression of renal cell cancer by directly targeting CDK6

The function of miR-186 in the progression of renal cell carcinoma (RCC) remains poorly investigated. Our study aims to identify the molecular mechanism underlying miR-186-regulated proliferation, migration and invasion of RCC. Firstly, our data confirmed that miR-186 was significantly reduced and CDK6 was obviously increased in RCC tissues and cells. MiR-186 or CDK6 was associated with advanced TNM stage, lymph node metastasis and poor prognosis. MiR-186 significantly inhibited cell proliferation, migration, invasion and in vivo tumor growth, induced apoptosis, and blocked cell cycle progression in G0/G1 phase. MiR-186 also induced Bax expression and inhibited the expressions of Bcl-2, cyclin D1 and epithelial-mesenchymal transition (EMT)-related genes. Additionally, CDK6 expression was downregulated by miR-186 via binding to its 3'-untranslated region (3'-UTR). Moreover, ectopic expression of CDK6 could partially abrogate the inhibitory effect of miR-186. In conclusion, miR-186 suppresses proliferation, migration and invasion of RCC by inhibiting CDK6 expression.

The Dual Role of miR-186 in Cancers: Oncomir Battling With Tumor Suppressor miRNA

MicroRNAs (miRNAs) are a class of small non-coding RNAs which regulate gene expression at post-transcriptional level. Alterations of miR-186 expression were demonstrated in numerous cancers, shown to play a vital role in oncogenesis, invasion, metastasis, apoptosis, and drug resistance. MiR-186 was documented as a tumor suppressor miRNA in the majority of studies, while conflicting reports verified miR-186 as an oncomir. The contradictory role in cancers may impede the application of miR-186, as well as other dual-functional miRNAs, as a diagnostic and therapeutic target. This review emphasizes the alterations and functions of miR-186 in cancers and discusses the mechanisms behind the contradictory findings. Among these, target abundance and dose-dependent effects of miR-186 are highlighted. The paper aims to review the challenges involved in developing diagnostic and therapeutic strategies for cancer treatment based on dual-functional miRNAs.

Recurrence-Associated Multi-RNA Signature to Predict Disease-Free Survival for Ovarian Cancer Patients

Ovarian cancer (OvCa) is an intractable gynecological malignancy due to the high recurrence rate. Several molecular biomarkers have been previously screened for early identifying patients with a high recurrence risk and poor prognosis. However, all the known studies focused on a single type of RNAs, not integrating various types. This study was to construct a new multi-RNA-based model to predict the recurrence and prognosis for OvCa patients by using the messenger RNA (mRNA, including long noncoding RNA (lncRNA)) and microRNA (miRNA) sequencing data of The Cancer Genome Atlas database. After univariate Cox regression and least absolute shrinkage and selection operator analyses, a multi-RNA-based signature (2 miRNAs: hsa-miR-508, hsa-miR-506; 1 lncRNA: TM4SF1-AS1; 11 mRNAs: MAGI3, SLAMF7, GLI2, PDK1, ARID3A, PLEKHG4B, TNFAIP8L3, C1QTNF3, NDUFAF1, CH25H, TMEM129) was generated and used to establish a risk score model. The high- and low-risk patients classified by the median risk score exhibited significantly different recurrence risks (89% versus 61%, p < 0.001) and survival time (the area under the receiver operating characteristic curve (AUC) = 0.901 for 5-year disease-free survival (DFS)). This risk model was independent of other clinical features and superior to pathologic staging for DFS prediction (AUC, 0.906 versus 0.524; C-index, 0.633 versus 0.510). Furthermore, some new interaction axes were revealed to explain the possible functions of these RNAs (competing endogenous RNA: TM4SF1-AS1-miR-186-STEAP2, LINC00536-miR-508-STEAP2, LINC00475-miR-506-TMEM129; coexpression: LINC00598-PLEKHG4B). In conclusion, this multi-RNA-based risk model may be clinically useful to stratify OvCa patients with different recurrence risks and survival outcomes and included RNAs may be potential therapeutic targets.

During mitosis ZEB1 "switches" from being a chromatin-bound epithelial gene repressor, to become a microtubule-associated protein

Microtubules are polymers of α/β-tubulin, with microtubule organization being regulated by microtubule-associated proteins (MAPs). Herein, we describe a novel role for the epithelial gene repressor, zinc finger E-box-binding homeobox 1 (ZEB1), that "switches" from a chromatin-associated protein during interphase, to a MAP that associates with α-, β- and γ-tubulin during mitosis. Additionally, ZEB1 was also demonstrated to associate with γ-tubulin at the microtubule organizing center (MTOC). Using confocal microscopy, ZEB1 localization was predominantly nuclear during interphase, with α/β-tubulin being primarily cytoplasmic and the association between these proteins being minimal. However, during the stages of mitosis, ZEB1 co-localization with α-, β-, and γ-tubulin was significantly increased, with the association commonly peaking during metaphase in multiple tumor cell-types. ZEB1 was also observed to accumulate in the cleavage furrow during cytokinesis. The increased interaction between ZEB1 and α-tubulin during mitosis was also confirmed using the proximity ligation assay. In contrast to ZEB1, its paralog ZEB2, was mainly perinuclear and cytoplasmic during interphase, showing some co-localization with α-tubulin during mitosis. Considering the association between ZEB1 with α/β/γ-tubulin during mitosis, studies investigated ZEB1's role in the cell cycle. Silencing ZEB1 resulted in a G₂-M arrest, which could be mediated by the up-regulation of p21^Waf1/Cip1 and p27^Kip1 that are known downstream targets repressed by ZEB1. However, it cannot be excluded the G₂/M arrest observed after ZEB1 silencing is not due to its roles as a MAP. Collectively, ZEB1 plays a role as a MAP during mitosis and could be functionally involved in this process.

BAG2 Promotes Proliferation and Metastasis of Gastric Cancer via ERK1/2 Signaling and Partially Regulated by miR186

Bcl2-associated athanogene (BAG)2 as a co-chaperone has been demonstrated to be involved in tumor growth and metastasis, but its biological function in gastric cancer remains unknown. Here, we reported that BAG2 was highly expressed in gastric cancer cell lines and tissues, indicating poor prognosis. High expression of BAG2 was significantly associated with T stage and differentiation level of gastric cancer (P < 0.001). Functional experiments revealed that BAG2 knockdown in gastric cancer cells inhibited the proliferation, invasion and migration of cells through AKT/mTOR and extracellular regulated kinase (ERK) pathways. Proteomic analysis identified that BAG2 may be involved in the regulation of mitogen-activated protein kinase (MAPK) pathway. In addition, immunoprecipitation showed that BAG2 could bind to ERK1/2. Luciferase reporter assay and Western blot verified that BAG2 was down-regulated by miR186. Taken together, our findings may reveal the basic function of BAG2 and uncover a potential therapeutic target for gastric cancer.

PVT1 Long Non-coding RNA in Gastrointestinal Cancer

Whole genome and transcriptome sequencing technologies have led to the identification of many long non-coding RNAs (lncRNAs) and stimulated the research of their role in health and disease. LncRNAs participate in the regulation of critical signaling pathways including cell growth, motility, apoptosis, and differentiation; and their expression has been found dysregulated in human tumors. Thus, lncRNAs have emerged as new players in the initiation, maintenance and progression of tumorigenesis. PVT1 (plasmacytoma variant translocation 1) lncRNA is located on chromosomal 8q24.21, a large locus frequently amplified in human cancers and predictive of increased cancer risk in genome-wide association studies (GWAS). Combined, colorectal and gastric adenocarcinomas are the most frequent tumor malignancies and also the leading cause of cancer-related deaths worldwide. PVT1 expression is elevated in gastrointestinal tumors and correlates with poor patient prognosis. In this review, we discuss the mechanisms of action underlying PVT1 oncogenic role in colorectal and gastric cancer such as MYC upregulation, miRNA production, competitive endogenous RNA (ceRNA) function, protein stabilization, and epigenetic regulation. We also illustrate the potential role of PVT1 as prognostic biomarker and its relationship with resistance to current chemotherapeutic treatments.

MicroRNAs and Metastasis

Metastasis, the development of secondary malignant growths at a distance from the primary site of a cancer, is associated with almost 90% of all cancer deaths, and half of all cancer patients present with some form of metastasis at the time of diagnosis. Consequently, there is a clear clinical need for a better understanding of metastasis. The role of miRNAs in the metastatic process is beginning to be explored. However, much is still to be understood. In this review, we present the accumulating evidence for the importance of miRNAs in metastasis as key regulators of this hallmark of cancer.

Silencing circular RNA circZNF609 restrains growth, migration and invasion by up-regulating microRNA-186-5p in prostate cancer

Background: Prostate cancer (PC) fearfully impacts men's health. We explored the efficacy and mechanism of circular RNA circZNF609 (circZNF609) on colony formation, viability, apoptosis, migration and invasion and in PC cells. Methods: Colony formation, CCK-8, flow cytometry, migration and invasion assay were respectively used to detect the functions of circZNF609 and microRNA (miR)-186-5p on cell colony ability, viability, apoptosis, migration and invasion. circZNF609 and miR-186-5p expression were changed by cell transfection and tested by RT-qPCR. Moreover, Cleaved-Caspase-3, Cleaved-Caspase-9, matrix metalloproteinase-9 (MMP-9), Vimentin and relate-proteins of cell pathways were examined through Western blot. Results: circZNF609 was highly expressed at PC tissues. circZNF609 declined cell colony ability, viability, migration and invasion and caused apoptosis. Furthermore, circZNF609 negatively regulated miR-186-5p, miR-186-5p inhibitor could reverse impacts of circZNF609. Finally, circZNF609 restrained the YAP1 and AMPK pathways by up-regulating miR-186-5p. Conclusion: Silencing circZNF609 restrained growth, migration and invasion of PC cells by up-regulating miR-186-5p via YAP1 and AMPK pathways. Highlights circZNF609 is highly expressed in PC tissues; circZNF609 restrains cell growth, migration and invasion; circZNF609 exerts its function by up-regulating miR-186-5p; circZNF609 exerts its function by YAP1 and AMPK signaling pathways.

MicroRNA-186-5p Inhibits Proliferation And Metastasis Of Esophageal Cancer By Mediating HOXA9

Objective

MicroRNA (miRNA) is an endogenous, non-coding small RNA that plays a key role in regulating organism biology and pathology. The aim of this study was to investigate the expression characteristics of microRNA-186-5p in esophageal cancer (ECa) and its correlation with clinical progression and prognosis, and to further explore its underlying mechanisms.

Methods

Real-time quantitative PCR (qRT-PCR) was used to detect microRNA-186-5p level in 45 pairs of ECa tissue samples and adjacent ones, and to analyze the expression of microRNA-186-5p and clinical progression of ECa and prognosis. The relationship between microRNA-186-5p level in ECa cell lines was further verified by qRT-PCR. Finally, the potential mechanism was explored using luciferase reporter gene assay and cell recovery experiment.

Results

QRT-PCR results revealed that the expression of microRNA-186-5p in ECa tissues was remarkably lower than that in adjacent tissues, and the difference was statistically significant. Compared with patients with high expression of microRNA-186-5p, patients with low expression of microRNA-186-5p had higher incidence of pathological stage and lower overall survival rate. Besides, compared with the miR-NC group, the microRNA-186-5p mimics group had a significant decrease in proliferation and metastasis ability of ECa cells. Subsequent qRT-PCR validation in ECa cell lines and tissues indicated a significant increase in HOXA9 expression and a negative correlation with microRNA-186-5p.

Conclusion

The expression of microRNA-186-5p was remarkably decreased in ECa, which was remarkably correlated with pathological stage, distant metastasis and poor prognosis of ECa. The results suggested that microRNA-186-5p may inhibit cell proliferation of ECa by regulating HOXA9.

LINC00473/miR-497-5p Regulates Esophageal Squamous Cell Carcinoma Progression Through Targeting PRKAA1

Background: Esophageal squamous cell carcinoma (ESCC) is one of the esophageal cancers known as an aggressive malignant tumor. Long noncoding RNAs (lncRNAs) can be involved in the progression and development of cancers. lncRNA LINC00473 (LINC00473) was reported to exert an oncogenic influence on diverse cancers. However, neither the biological function nor the underlying mechanism of LINC00473 has been explored in ESCC. Aim of the Study: The aim of investigation is to explore the role of LINC00473 in ESCC. Methods: The expression of LINC00473, miR-497-5p, and protein kinase AMP-activated alpha 1 catalytic subunit (PRKAA1) was detected by reverse-transcription quantitative polymerase chain reaction assay. Cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays were carried out to measure cell proliferation. Cell migration was tested by transwell assay. Western blot assay was performed to examine the protein expression of PRKAA1, E-cadherin, N-cadherin, and Vimentin. The binding capacity between miR-497-5p and LINC00473 (or PRKAA1) was, respectively, studied by luciferase reporter and RNA immunoprecipitation assays. Pearson correlation analysis was adopted to analyze the correlation between miR-497-5p (or LINC00473) and PRKAA1. Results: LINC00473 presented much higher expression and LINC00473 suppression restrained the proliferation, migration, and epithelial-mesenchymal transition (EMT) process in ESCC cells. MiR-497-5p presented lower expression, binding with and negatively regulated by LINC00473 in ESCC. PRKAA1 was confirmed as a downstream target gene for miR-497-5p. PRKAA1 could combine with miR-497-5p, and LINC00473 knockdown or miR-497-5p overexpression downregulated the mRNA and protein expression of PRKAA1. At last, the inhibitory effects of LINC00473 knockdown on proliferation, migration, and EMT process were reversed by PRKAA1 overexpression in vitro and in vivo. Conclusions: LINC00473 regulates ESCC progression through miR-497-5p/PRKAA1 axis, which provides a new therapeutic strategy for ESCC patients.

Functions and mechanisms of miR-186 in human cancer

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression at the post-transcriptional level. Mounting evidence suggests the involvement of miRNAs in carcinogenesis and the development of human cancer. Among the miRNAs, miR-186 has been extensively studied in various cancers. The expression of miR-186 in tissues varies depending on the type of cancer and miR-186 in tissues and body fluids may serve as a marker for the diagnosis and prognosis of cancers. Various biological processes in human cancer are affected by miR-186. Additionally, miR-186 itself is regulated by several factors. Thus, this evidence highlights the potential value of miR-186 in the diagnosis, prognosis and treatment of human cancer.

Long Intergenic Non-Protein Coding RNA 665 Regulates Viability, Apoptosis, and Autophagy via the MiR-186-5p/MAP4K3 Axis in Hepatocellular Carcinoma

PURPOSE

Long intergenic non-protein coding RNA 665 (LINC00665) plays a vital role in the development of cancer. Its function in hepatocellular carcinoma (HCC), however, remains largely unknown.

MATERIALS AND METHODS

The expressions of LINC00665, miR-186-5p, and MAP4K3 were determined by qRT-PCR. Cell viability and apoptosis were evaluated by MTT and flow cytometry, respectively. Autophagic puncta formation was observed by fluorescence microscopy. Bioinformatics analysis, luciferase reporter assay, RNA immunoprecipitation, and RNA pulldown were performed to identify associations among LINC00665, miR-186-5p, and MAP4K3. Western blot was utilized to examine the expressions of MAP4K3, Beclin-1, and LC3. Tumor growth was evaluated in a xenograft model.

RESULTS

Elevations in LINC00665 were observed in HCC tissues and cells. The overall survival of HCC patients with high levels of LINC00665 was shorter than those with low levels. In vitro, LINC00665 depletion inhibited viability and induced apoptosis and autophagy. miR-186-5p interacted with LINC00665 and was downregulated in HCC tissues and cells. Upregulation of miR-186-5p inhibited viability and induced apoptosis and autophagy, which were attenuated by upregulation of LINC00665. MAP4K3 was found to possess binding sites with miR-186-5p and was upregulated in HCC tissues and cells. MAP4K3 depletion inhibited viability and induced apoptosis and autophagy, which were attenuated by miR-186-5p inhibitor. In vivo, miR-186-5p expression was negatively correlated with LINC00665 or MAP4K3 in HCC tissues, while LINC00665 was positively correlated with MAP4K3. LINC00665 knockdown suppressed tumor growth.

CONCLUSION

LINC00665 was involved in cell viability, apoptosis, and autophagy in HCC via miR-186-5p/MAP4K3 axis, which may provide a new approach for HCC treatment.

Deep RNA-Seq reveals miRNome differences in mammary tissue of lactating Holstein and Montbéliarde cows

Background

Genetic polymorphisms are known to influence milk production and composition. However, the genomic mechanisms involved in the genetic regulation of milk component synthesis are not completely understood. MicroRNAs (miRNAs) regulate gene expression. Previous research suggests that the high developmental potential of the mammary gland may depend in part on a specific miRNA expression pattern. The objective of the present study was to compare the mammary gland miRNomes of two dairy cow breeds, Holstein and Montbéliarde, which have different mammogenic potentials that are related to differences in dairy performance.

Results

Milk, fat, protein, and lactose yields were lower in Montbéliarde cows than in Holstein cows. We detected 754 distinct miRNAs in the mammary glands of Holstein (n = 5) and Montbéliarde (n = 6) midlactating cows using RNA-Seq technology, among which 738 were known and 16 were predicted miRNAs. The 25 most abundant miRNAs accounted for 90.6% of the total reads. The comparison of their abundances in the mammary glands of Holstein versus Montbéliarde cows identified 22 differentially expressed miRNAs (P_adj ≤ 0.05). Among them, 11 presented a fold change ≥2, and 2 (miR-100 and miR-146b) were highly expressed. Among the most abundant miRNAs, miR-186 is known to inhibit cell proliferation and epithelial-to-mesenchymal transition.

Data mining showed that 17 differentially expressed miRNAs with more than 20 reads were involved in the regulation of mammary gland plasticity. Several of them may potentially target mRNAs involved in signaling pathways (such as mTOR) and lipid metabolism, thereby indicating that they could influence milk composition.

Conclusion

We found differences in the mammary gland miRNomes of two dairy cattle breeds. These differences suggest a potential role for miRNAs in mammary gland plasticity and milk component synthesis, both of which are related to milk production and composition. Further research is warranted on the genetic regulation of miRNAs and their role in milk synthesis.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5987-4) contains supplementary material, which is available to authorized users.

The role of PEG3 in the occurrence and prognosis of colon cancer

Purpose

Imprinted genes are often identified as key players in the etiology and prognosis of many tumors; however, the role they play in colon cancer remains unclear. Along with the development of big data analysis came the discovery of a wealth of genetic prognostic factors, like microsatellite instability for colon cancer, which need to be taken into consideration when evaluating new biomarkers for the disease.

Methods

We systematically mined public databases to find recurrence free survival (RFS)-related imprinted genes for colon cancer patients on the mRNA level by univariate and multivariate survival analyses. We then investigated the association of methylation status and microRNA expression of the targeted imprinted genes with survival rate of colon cancer patients. Lastly, in a clinical study we used qRT-PCR and immunohistochemistry to quantify mRNA and protein expression of the imprinted genes that related to RFS in our bioinformatics screening, respectively, in 20 tumor tissues compared to paired adjacent tissues.

Results

The results show that paternally expressed gene 3 (PEG3) is the only imprinted gene related to colon cancer patient prognosis on the mRNA level in our datasets, and high mRNA expression of PEG3 is associated with a poor prognosis. Furthermore, the methylation beta value of cg13960339, as well as the expression of 4 microRNAs, negatively correlated with PEG3 mRNA level and were correlated with the prognosis of colon cancer patients. Moreover, the expression of PEG3 mRNA in colon cancer is significantly lower, but PEG3 protein expression is significantly higher compared to that in normal tissues.

Conclusion

PEG3 is likely associated with the progression and prognosis of colon cancer.

Long noncoding RNA SNHG14 facilitates colorectal cancer metastasis through targeting EZH2-regulated EPHA7

Accumulating evidence suggested the participation of long noncoding RNAs (lncRNAs) in regulating various biological processes so as to affecting cancer progression. However, the functional role of most lncRNAs in colorectal carcer (CRC) is still largely covered. In the present study, we disclosed SNHG14 as a carcinogene in CRC development, as it was low-expressed in normal colon tissues but markedly upregulated in CRC cell lines. Besides, SNHG14 contributed to CRC cell proliferation, motility and EMT in vitro, and inhibition of it confined CRC tumor growth and liver metastasis in vivo. Next, the mechanistic investigations confirmed that SNHG14-promoted CRC progression was mediated by EPHA7, which was negatively regulated by SNHG14 in CRC via an EZH2-dependent way. Importantly, EZH2 was proved as a transcription factor of EPHA7 and functioned as a repressor in EPHA7 transcription by enhancing methylation on EPHA7 promoter. Meanwhile, SNHG14 increased EZH2 expression in CRC via stabilizing its mRNA by interacting with FUS, and via freeing its mRNA from miR-186-5p-induced silence. All in all, our observations demonstrated that SNHG14 serves as a facilitator in CRC through targeting EZH2-repressed EPHA7 by enhancing EZH2 via recruiting FUS and absorbing miR-186-5p, indicating a promising new road for CRC diagnosis and treatment.

Role of circular RNAs in gastric cancer: Recent advances and prospects

Circular RNA (circRNA) is a newly discovered non-coding RNA with special structure, which is widely expressed in eukaryotic organisms and mainly located in the cytoplasm. circRNAs participate in gene regulation by working as miRNA sponges that block the inhibitory effect of miRNA on its target genes. In addition, circRNAs can bind to RNA binding proteins to regulate gene expression. Based on characteristics of stability, expression specificity and participation in gene regulation, circRNAs are expected to be biomarkers for early diagnosis of cancer or potential targets for cancer therapy. With the help of bioinformatics analysis, circRNA microarray analysis and high-throughput sequencing technology, more circRNAs were discovered to participate in the progression of gastric cancer (GC) over the past three years. This article gives an overview of these recent research focusing on the roles of circRNAs in GC and highlights the advances.

Anti-tumor Drug THZ1 Suppresses TGFβ2-mediated EMT in Lens Epithelial Cells via Notch and TGFβ/Smad Signaling Pathway

Selective covalent CDK7 inhibitor THZ1 is a promising potential anti-tumor drug in many kinds of cancers. Epithelial-mesenchymal Transition (EMT) is highly related to cancer initiation, development, invasion and metastasis and other pathogenesis processes. We treated cancer cell line Hela229 and three retinoblastoma cell lines so-RB50, WERI-Rb-1, Y79 with gradient concentration of THZ1, and found that THZ1 could inhibit cell viability and EMT, suggesting that THZ1 may be a promising drug for human cervical cancer and retinoblastoma treatment. Our results verified the role of THZ1 in EMT for the first time, however, the mechanism needs further study. Here we report that THZ1 suppresses the TGFβ2 induced EMT in human SRA01/04 lens epithelial cells (LECs), rabbit primary lens epithelial cells, and whole rat lens culture semi-in vivo model. RNA-sequencing and KEGG analysis revealed that the THZ1 inhibits EMT by down-regulating phosphorylate Smad2 and Notch signaling pathway. On the other hand, we found that THZ1 could strongly inhibit LECs proliferation through G2/M phase arrest as well as attenuating of MAPK, PI3K/AKT signaling pathway. Our results uncovered the function and underlying mechanism of THZ1 in regulation of EMT, which provides a new perspective of the anti-tumor effect by THZ1 and may offer a novel treatment for PCO.

MicroRNA‑708 inhibits the proliferation and invasion of osteosarcoma cells by directly targeting ZEB1

Numerous microRNAs (miRNAs) have been identified as aberrantly expressed in osteosarcoma (OS). miRNAs serve important roles in the pathogenesis of OS as oncogenes or tumor suppressors. Recent studies revealed that miR‑708‑5p (miR‑708) was dysregulated in various types of human cancer; however, its roles and underlying molecular mechanisms in OS remain unknown. Therefore, the present study aimed to determine miR‑708 expression in OS, investigate the roles of miR‑708 in the progression of OS and reveal the potential mechanisms involved. It was demonstrated using reverse transcription‑polymerase chain reaction that miR‑708 was downregulated in OS tissues and cell lines. Cell Counting Kit‑8 and Transwell assays revealed that miR‑708 overexpression suppressed the proliferation and invasion of OS cells in vitro. Additionally, zinc finger E‑box binding homeobox 1 (ZEB1) was validated as a direct target gene of miR‑708 in OS cells. ZEB1 was upregulated in OS tissues; elevated ZEB1 expression was negatively correlated with the levels of miR‑708 expression. Rescue experiments indicated that ZEB1 reintroduction significantly counteracted the inhibitory effects of miR‑708 overexpression on the proliferation and invasion of OS cells. The findings may improve understanding of the roles of miR‑708 in the development of OS, and suggest that miR‑708 may be a potential novel therapeutic target in the treatment of patients with this disease.

miR-186-5p promotes cell growth, migration and invasion of lung adenocarcinoma by targeting PTEN

OBJECTIVE

To explore the expression of miR-186-5p in lung adenocarcinoma (LUAD) and its possible function associated with cancer cell proliferation, migration and invasion.

METHODS

MiR-186-5p expression levels in LUAD samples, human LUAD cell lines H1299 and NCI-H1975, and normal human lung epithelial cell line BEAS-IB were assessed by quantitative real-time PCR (qRT-PCR). H1299 and NCI-H1975 cells were transfected with miR-186-5p mimic or miRNA negative control. CCK-8 assay was performed to evaluate the cell proliferation. Transwell assay and transwell-matrigel™ invasion assay were applied to assess the migration and invasion abilities of H1299 and NCI-H1975 cells.

RESULTS

miR-186-5p expression was significantly up-regulated in LUAD tumor tissues and LUAD cell lines as compared with tumor-adjacent tissues and normal human lung epithelial cells, respectively. MiR-186-5p overexpression remarkably promoted the proliferation, migration and invasion of LUAD cells. Furthermore, phosphatase and tensin homolog (PTEN) was a direct target of miR-186-5p verified by luciferase reporter assay. Overexpression of PTEN significantly suppressed LUAD cells to proliferate, migrate and invade. MiR-186-5p overexpression-induced LUAD cell phenotype could be partially rescued by co-overexpression of miR-186-5p and PTEN.

CONCLUSION

This study demonstrated that miR-186-5p is up-regulated in LUAD, and functionally associated with cell proliferation, migration and invasion. MiR-186-5p promotes the proliferation, migration and invasion of LUAD cells by targeting PTEN. MiR-186-5p may be utilized as a novel molecular marker and therapeutic target of LUAD.

Upregulation of FoxP4 in HCC promotes migration and invasion through regulation of EMT

Previous studies have indicated that FoxP1, FoxP2 and FoxP3 play important roles in hepatocellular carcinoma (HCC). However, the effect of FoxP4 in HCC requires further elucidation. The aim of the present study was to explore the roles of FoxP4 in HCC and further decipher the detailed mechanism. In present study, it was found that FoxP4, which is overexpressed in HCC tissues and cell lines, facilitated EMT in HCC cell lines through regulation of Slug. First, increased expression of FoxP4 was identified in 110 pairs of human HCC tumor and their adjacent normal tissues. In addition, the association between FoxP4 expression and clinicopathological features of HCC patients indicated that FoxP4 played vital roles in HCC development. Subsequently, gain- and loss-of-function experiments indicated that FoxP4 promoted cellular proliferation, migration as well invasion. In addition, EMT, a key mechanism during cancer metastasis, was regulated by FoxP4. Furthermore, ChIP and qChIP as well as luciferase reporter assays indicated that Slug, an EMT-associated transcription factor, was transcriptionally regulated by FoxP4. In conclusion, FoxP4 functioned as a tumor promoter in HCC cells by transcriptionally regulating Slug, and the present study highlighted the potential effects of FoxP4 on the prognosis and treatment of HCC.

Emerging microRNA biomarkers for colorectal cancer diagnosis and prognosis

MicroRNAs (miRNAs) are one abundant class of small, endogenous non-coding RNAs, which regulate various biological processes by inhibiting expression of target genes. miRNAs have important functional roles in carcinogenesis and development of colorectal cancer (CRC), and emerging evidence has indicated the feasibility of miRNAs as robust cancer biomarkers. This review summarizes the progress in miRNA-related research, including study of its oncogene or tumour-suppressor roles and the advantages of miRNA biomarkers for CRC diagnosis, treatment and recurrence prediction. Along with analytical technique improvements in miRNA research, use of the emerging extracellular miRNAs is feasible for CRC diagnosis and prognosis.

MicroRNA-186 promotes cell proliferation and inhibits cell apoptosis in cutaneous squamous cell carcinoma by targeting RETREG1

MicroRNAs (miRs), a class of small non-coding RNAs, have been demonstrated to be involved in the development and progression of human malignancies, including cutaneous squamous cell carcinoma (CSCC). miR-186 serves a suppressive role in certain common types of human cancer; however, its exact function in CSCC has not been reported previously. In the present study, the expression of miR-186 was significantly increased in CSCC tissues compared with adjacent non-tumour tissues. Overexpression of miR-186 significantly promoted CSCC cell proliferation while inhibiting cell apoptosis. Reticulophagy regulator 1 (RETREG1), a gene that is significantly downregulated in CSCC tissues and cell lines, was identified as a novel target of miR-186. In addition, the expression of RETREG1 was inversely correlated with miR-186 expression in CSCC tissues. Furthermore, the expression of RETREG1 was negatively regulated by miR-186 in CSCC cells, and restoration of RETREG1 attenuated the effects of miR-186 on CSCC cells. Taken together, the results of the current study suggest that miR-186 serves an oncogenic role in CSCC and may be used as a potential therapeutic target for the treatment of this disease.

Retracted Article: Long non-coding RNA KCNQ1OT1 regulates cell proliferation, apoptosis and chemo-sensitivity through modulating the miR-186-5p/NCAM1 axis in acute myeloid leukemia cells

Recent studies show that lncRNA KCNQ1OT1 and microRNA-186-5p (miR-186-5p) are involved in various human cancers. Moreover, it is reported that KCNQ1OT1 expression is upregulated in acute myeloid leukemia (AML). However, their roles in AML remain unknown. This study aimed to reveal the functional mechanism of KCNQ1OT1 and miR-186-5p in AML development. Quantitative real time polymerase chain reaction (qRT-PCR) was performed to detect the levels of genes. Cell proliferation and apoptosis were assessed by a 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry analysis respectively. A western blot assay was carried out to examine the protein levels. In addition, the interaction between miR-186-5p and KCNQ1OT1 or neural cell adhesion molecule 1 (NCAM1) was predicted by bioinformatics analysis tool starbase2.0 and confirmed by the dual luciferase reporter assay. KCNQ1OT1 and NCAM1 expressions were increased and miR-186-5p expression was decreased in AML samples and cells. The depletion of KCNQ1OT1 inhibited cell proliferation, and promoted apoptosis and chemo-sensitivity in AML. In addition, the upregulation of miR-186-5p suppressed AML cell proliferation, and induced apoptosis and chemo-sensitivity. Interestingly, KCNQ1OT1 directly downregulated miR-186-5p expression and miR-186-5p decreased NCAM1 expression by binding to the 3′ untranslated region (UTR) of NCAM1 mRNA. Furthermore, miR-186-5p knockdown or NCAM1 overexpression reversed the effects of KCNQ1OT1 depletion on AML cell progression. Our results firstly revealed a linear relationship between KCNQ1OT1, miR-186-5p, and NCAM1, and demonstrated that KCNQ1OT1 mediated AML cell progression via regulating the miR-186-5p/NCAM1 axis, revealing functional mechanisms of KCNQ1OT1 and miR-186-5p in AML development.

Recent studies show that lncRNA KCNQ1OT1 and microRNA-186-5p (miR-186-5p) are involved in various human cancers.

MicroRNA-329-mediated PTTG1 downregulation inactivates the MAPK signaling pathway to suppress cell proliferation and tumor growth in cholangiocarcinoma

Cholangiocarcinoma (CCA) is a severe malignancy usually producing a poor prognosis and high mortality rate. MicroRNAs (miRNAs) have been reported in association with CCA; however, the role miR-329 plays in the CCA condition still remains unclear. Therefore, this study was conducted to explore the underlying mechanism of which miR-329 is influencing the progression of CCA. This work studied the differential analysis of the expression chips of CCA obtained from the Gene Expression Omnibus database. Next, to determine both the expression and role of pituitary tumor transforming gene-1 (PTTG1) in CCA, the miRNAs regulating PTTG1 were predicted. In the CCA cells that had been intervened with miR-329 upregulation or inhibition, along with PTTG1 silencing, expression of miR-329, PTTG1, p-p38/p38, p-ERK5/ERK5, proliferating cell nuclear antigen (PCNA), Cyclin D1, Bcl-2-associated X protein (Bax), B-cell CLL/lymphoma 2 (Bcl-2), and caspase-3 were determined. The effects of both miR-329 and PTTG1 on cell proliferation, cell-cycle distribution, and apoptosis were also assayed. The miR-329 was likely to affect the CCA development through regulation of the PTTG1-mediated mitogen-activated protein kinase (MAPK) signaling pathway. The miR-329 targeted PTTG1, leading to inactivation of the MAPK signaling pathway. Upregulation of miR-329 and silencing of PTTG1 inhibited the CCA cell proliferation, induced cell-cycle arrest, and subsequently promoted apoptosis with elevations in Bax, cleaved caspase-3, and total caspase-3, but showed declines in PCNA, Cyclin D1, and Bcl-2. Moreover, miR-329 was also found to suppress the tumor growth by downregulation of PTTG1. To summarize, miR-329 inhibited the expression of PTTG1 to inactivate the MAPK signaling pathway, thus suppressing the CCA progression, thereby providing a therapeutic basis for the CCA treatment.

miR-186 inhibits proliferation, migration, and epithelial-mesenchymal transition in breast cancer cells by targeting Twist1

OBJECTIVE

Breast cancer (BC) is the most prevalent malignancy in women worldwide. Our study aimed to investigate the expression and biological effect of miR-186 in BC.

METHODS

Expression of miR-186 was determined by quantitative reverse transcription PCR. Kaplan-Meier curves were calculated for the survival data analysis. Functional assays were performed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and wound healing assay. Protein expression was analyzed by Western blot.

RESULTS

miR-186 was downregulated in BC tissues and cells. Downregulation of miR-186 was associated with tumor metastasis and a poor overall survival in patients with BC. Overexpression of miR-186 inhibited BC cells proliferation, migration, and epithelial-mesenchymal transition process; while suppression of miR-186 exhibited an opposite effects on BC cells. In addition, Twist1 was identified as a direct target of miR-186 in BC and restoration of Twist1 attenuated the biological effect of miR-186 on BC cells.

CONCLUSION

Our findings suggest that miR-186 functions as a tumor suppressor by targeting Twist1 in BC. miR-186 may serve as a novel biomarker in BC diagnosis or a new therapeutic target in BC treatment.

Low expression of miR-186-5p regulates cell apoptosis by targeting toll-like receptor 3 in high glucose-induced cardiomyocytes

To investigate the effect and mechanism of microRNA-186-5p (miR-186-5p) on the apoptosis in high glucose (HG)-treated cardiomyocytes. Diabetic cardiomyopathy model was established in cardiomyocytes by stimulating with HG. The expressions of miR-186-5p and toll-like receptor 3 (TLR3) were detected by quantitative polymerase chain reaction or Western blot analysis, respectively. Apoptosis was detected in HG-treated cardiomyocytes by flow cytometry and Western blot analysis. The interaction between miR-186-5p and TLR3 was explored by bioinformatics analysis and luciferase activity assay. Results showed that miR-186-5p expression was downregulated in HG-treated cardiomyocytes and its overexpression reversed HG-induced apoptosis and cleaved caspase-3 protein expression. Moreover, TLR3 was indicated as a target of miR-186-5p and regulated by miR-186-5p. Knockdown of TLR3 suppressed HG-induced apoptosis and cleaved caspase-3 protein expression. Besides, restoration of TLR3 ablated the effect of miR-186-5p on cell apoptosis. Collectively, miR-186-5p attenuated HG-induced apoptosis by regulating TLR3 in cardiomyocytes, providing novel biomarker for treatment of diabetic cardiomyopathy.

EMT: A mechanism for escape from EGFR-targeted therapy in lung cancer

Epithelial mesenchymal transition (EMT) is a reversible developmental genetic programme of transdifferentiation of polarised epithelial cells to mesenchymal cells. In cancer, EMT is an important factor of tumour cell plasticity and has received increasing attention for its role in the resistance to conventional and targeted therapies. In this paper we provide an overview of EMT in human malignancies, and discuss contribution of EMT to the development of the resistance to Epidermal Growth Factor Receptor (EGFR)-targeted therapies in non-small cell lung cancer (NSCLC). Patients with the tumours bearing specific mutations in EGFR have a good clinical response to selective EGFR inhibitors, but the resistance inevitably develops. Several mechanisms responsible for the resistance include secondary mutations in the EGFR gene, genetic or non-mutational activation of alternative survival pathways, transdifferentiation of NSCLC to the small cell lung cancer histotype, or formation of resistant tumours with mesenchymal characteristics. Mechanistically, application of an EGFR inhibitor does not kill all cancer cells; some cells survive the exposure to a drug, and undergo genetic evolution towards resistance. Here, we present a theory that these quiescent or slow-proliferating drug-tolerant cell populations, or so-called "persisters", are generated via EMT pathways. We review the EMT-activated mechanisms of cell survival in NSCLC, which include activation of ABC transporters and EMT-associated receptor tyrosine kinase AXL, immune evasion, and epigenetic reprogramming. We propose that therapeutic inhibition of these pathways would eliminate pools of persister cells and prevent or delay cancer recurrence when applied in combination with the agents targeting EGFR.

Construction of an miRNA‑gene regulatory network in colorectal cancer through integrated analysis of mRNA and miRNA microarrays

The aim of the present study was to identify potential biomarkers associated with colorectal cancer (CRC). The GSE32323 and GSE53592 mRNA and microRNA (miRNA) expression profiles were selected from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) and differentially expressed miRNAs (DEMs) in CRC tissue samples compared with surrounding control tissue samples (DEGs‑CC), and DEGs in cells treated with 5‑aza‑2'‑deoxycitidine compared with untreated cells (DEGs‑TC) were identified with the Limma package. The Database for Annotation, Visualization and Integrated Discovery was used to conduct the functional and pathways enrichment analysis. Differential co‑regulation networks were constructed using the DCGL package of R. The targets of DEMs were identified using TargetScan. The overlaps between DEGs and the targets were selected. The miRNA‑gene regulatory network of the overlaps was established. There were 145 DEMs, and 1,284 DEGs in DEGs‑CC, and 101 DEGs in DEGs‑TC. DEGs‑CC were enriched in 196 Gene Ontology (GO) terms and 23 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. DEGs‑TC were enriched in 46 GO terms and two KEGG pathways. A differential co‑regulation network of the DEGs and a miRNA‑gene regulatory network between DEMs and overlapped DEGs were respectively constructed. miR‑124‑3p, miR‑145‑5p and miR‑320a may be critical in CRC, and serum/glucocorticoid regulated kinase 1 and SRY‑box 9 may be potential biomarkers for CRC tumor progression.

LncRNA TUG1 promoted KIAA1199 expression via miR-600 to accelerate cell metastasis and epithelial-mesenchymal transition in colorectal cancer

BACKGROUND

LncRNA TUG1 has been reported to be highly expressed in CRC samples and cells and promoted metastasis by affecting EMT, indicating a poor prognosis for colorectal cancer (CRC). In this study, we determined the underlying mechanism for tumor oncogenesis of lncRNA TUG1 in CRC metastasis.

METHODS

The expressions of miR-600 and KIAA1199 in 76 CRC patients and CRC cells and CRC metastatic tissues were determined using qRT-PCR. Epithelial-mesenchymal transition (EMT)-related proteins were determined using western blot. CRC cell metastasis was assessed by colony formation, wound healing and transwell assay. Luciferase reporter gene assay was used to confirm miR-600 binding to KIAA1199 3'UTR.

RESULTS

Our data showed that lncRNA TUG1 was upregulated in CRC cells, miR-600 was downregulated in CRC tissues, cell lines and CRC metastatic tissues, and low miR-600 expression predicted a poor clinical prognosis. Overexpression of miR-600 suppressed CRC cell migration/invasion and EMT-related proteins in vitro, inhibited tumor volume and weight, and decreased the number of CRC liver metastasis in vivo. KIAA1199 was upregulated in CRC tissues, and was negatively regulated by miR-600. KIAA1199 overexpression promoted CRC cell migration and invasion, which reversed the inhibition effect of miR-600 mimic on migration and invasion of CRC cells. Moreover, TUG1 negatively regulated miR-600, and inhibition of TUG1 suppressed CRC cell migration and invasion and EMT-related proteins via regulating miR-600.

CONCLUSION

Our study proved that TUG1 promoted KIAA1199 expression to accelerate EMT and metastasis of CRC cell through inhibition of miR-600 expression.