microRNA-217 inhibits tumor progression and metastasis by downregulating EZH2 and predicts favorable prognosis in gastric cancer

LncRNA-NEAT1 blocks the Wnt/β-catenin signaling pathway by targeting miR-217 to inhibit trophoblast cell migration and invasion

OBJECTIVE

This study aimed to study the correlation between preeclampsia (PE) and lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1), and to examine the molecular mechanisms behind the development of PE.

METHODS

30 PE and 30 normal pregnant women placental samples were assessed the levels of NEAT1 and miR-217 by quantitative real-time PCR (qRT-PCR). The trophoblast cell line HTR8/SVneo was used for silencing NEAT1 or miR-217 inhibitor in the absence or presence of an inhibitor and H2O2. Cell counting Kit 8 (CCK-8), flow cytometry, and Transwell were used to detect cell proliferation, apoptosis, migration, and invasion. Luciferase reporter gene assay was utilized to verify the binding between miR-217 and Wnt family member 3 (Wnt3), and between the miR-217 and NEAT1. Proteins related to the Wnt/β-catenin signaling pathway were detected using western blotting.

RESULTS

The PE group exhibited a significantly downregulated expression of miR-217 and a significantly upregulated expression of NEAT1. NEAT1 targeted miR-217, and Wnt is a miR-217 target gene. siRNA-NEAT1 inhibited the apoptosis of trophoblast cells, but promoted their invasion, migration, and proliferation. MiR-217 inhibitor could partially reverse the effects of siRNA-NEAT1. The expression of the Wnt/β-catenin signaling pathway-related proteins, WNT signaling pathway inhibitor 1 (DKK1), cyclin-D1 and β-catenin, was significantly increased after siRNA-NEAT1.

CONCLUSIONS

NEAT1 could reduce trophoblast cell invasion and migration by suppressing miR-217/Wnt signaling pathway, leading to PE.

miR-217 Regulates Normal and Tumor Cell Fate Following Induction of Endoplasmic Reticulum Stress

Rapidly proliferating cancer cells require a microenvironment where essential metabolic nutrients like glucose, oxygen, and growth factors become scarce as the tumor volume surpasses the established vascular capacity of the tissue. Limits in nutrient availability typically trigger growth arrest and/or apoptosis to prevent cellular expansion. However, tumor cells frequently co-opt cellular survival pathways thereby favoring cell survival under this environmental stress. The unfolded protein response (UPR) pathway is typically engaged by tumor cells to favor adaptation to stress. PERK, an endoplasmic reticulum (ER) protein kinase and UPR effector is activated in tumor cells and contributes tumor cell adaptation by limiting protein translation and balancing redox stress. PERK also induces miRNAs that contribute to tumor adaptation. miR-211 and miR-216b were previously identified as PERK-ATF4-regulated miRNAs that regulate cell survival. We have identified another PERK-responsive miRNA, miR-217, with increased expression under prolonged ER stress. Key targets of miR-217 are identified as TRPM1, the host gene for miR-211 and EZH2. Evidence is provided that miR-217 expression is essential for the rapid loss of miR-211 in prolonged ER stress and provides a functional link for determining whether cells adapt to stress or commit to apoptosis.

IMPLICATIONS

PERK-dependent induction of miR-217 limits accumulation and function of the prosurvival miRNA, miR-211, to establish cell fate and promote cell commitment to apoptosis.

Extracellular vesicles derived from mesenchymal stem cells confer protection against intervertebral disc degeneration through a microRNA-217-dependent mechanism

OBJECTIVE

Extracellular vesicles released by mesenchymal stem cells (MSC-EVs) can be applied to alleviate intervertebral disc degeneration (IVDD) by curbing apoptosis of nucleus pulposus cells (NPCs). The current study aims to evaluate the effect of MSC-EVs on NPC apoptosis and IVDD and the related regulatory mechanisms involving microRNA (miR)-217.

METHOD

Expression of miR-217 was examined in tumor necrosis factor-α (TNF-α)-induced NPCs and MSC-EVs, followed by identification in the relationship between miR-217, enhancer of zeste homolog 2 (EZH2) and forkhead box O-3 (FOXO3). After isolation of EVs from MSCs and subsequent co-culture with NPCs, we assessed effects of miR-217 on NPC viability, autophagy, senescence and apoptosis along with extracellular matrix (ECM) degradation. Further in vivo experiments were conducted in rat models of IVDD to substantiate the effect of miR-217 on IVDD.

RESULTS

Poor miR-217 expression was found in TNF-α-induced NPCs, while high miR-217 expression was identified in MSC-EVs (P < 0.05). MSC-EVs transferred miR-217 to NPCs and increased its expression, thus attenuating NPC apoptosis and ECM degradation (elevated collagen II and aggrecan but reduced MMP13 and ADAMTS5) (P < 0.05). miR-217 targeted EZH2, and EZH2 bound to the FOXO3 promoter and consequently downregulated its expression. FOXO3 restrained NPC apoptosis and ECM degradation by stimulating cell autophagy (P < 0.05). Furthermore, in vivo experimental results confirmed the suppressive role of miR-217 shuttled by MSC-EVs in IVDD.

CONCLUSION

Overall, the delivery of miR-217 may be a novel mechanism underlying the effect of MSC-EVs on NPC apoptosis and ECM degradation following IVDD.

miR‑217‑5p suppresses epithelial‑mesenchymal transition and the NF‑κB signaling pathway in breast cancer via targeting of metadherin

MicroRNAs (miRNAs) have been associated with a number of human malignancies, including breast cancer (BC). However, the expression, biological function and fundamental underlying mechanism of miR-217-5p in BC remain unclear. Therefore, in the present study, the expression levels of miR-217-5p and metadherin (MTDH) were examined in BC tissues and BC cell lines using reverse transcription-quantitative PCR. Cell Counting Kit-8 assays, cell proliferation, wound healing assays, Transwell assays and western blotting were used to examine the effects of miR-217-5p on cell proliferation, migration, the epithelial-mesenchymal transition (EMT) and NF-κB signaling pathway expression. The direct relationship between miR-217-5p and MTDH was assessed using a dual-luciferase reporter assay. The results demonstrated that significantly reduced expression levels of miR-217-5p but significantly increased mRNA expression levels of MTDH were observed in BC tissues from 35 patients with BC compared with non-tumor breast tissues. Furthermore, BC cell lines SK-BR3 and BT549 expressed miR-217-5p at markedly lower levels and MTDH at markedly higher levels compared with the breast epithelial MCF10A cell line. miR-217-5p overexpression significantly inhibited cell proliferation, invasion and migration and suppressed the EMT in BC cells. miR-217-5p overexpression also inhibited the NF-κB signaling pathway by markedly decreasing p65 mRNA and protein expression levels but significantly increasing IκBα expression levels. Furthermore, miR-217-5p knockdown markedly increased MTDH mRNA and protein expression levels. The expression levels of miR-217-5p were negatively correlated with those of MTDH in BC tissues. These results suggested that restoration of MTDH expression levels could potentially attenuate the inhibitory effects of miR-217-5p overexpression on BC cell proliferation. Therefore, in conclusion miR-217-5p overexpression may inhibit cell migration, invasion, the EMT and NF-κB signaling pathway in BC via targeting of MTDH. miR-217-5p may serve as an important potential target in BC therapy.

HIF1A-AS2 Promotes the Proliferation and Metastasis of Gastric Cancer Cells Through miR-429/PD-L1 Axis

BACKGROUND

Gastric cancer (GC) is a common leading cause of cancer-related mortality of all malignancies. LncRNA hypoxia-inducible factor-1 alpha antisense RNA-2 (HIF1A-AS2) has been identified to involve in the development of GC. Therefore, we further explored the detailed molecular mechanism of HIF1A-AS2 in GC progression.

METHODS

The expression of HIF1A-AS2, microRNA-429 (miR-429), and programmed cell death ligand 1 (PD-L1) was measured using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Cell proliferation, migration, and invasion abilities were detected by Cell Counting Kit-8 (CCK-8) or transwell assay. The interaction between miR-429 and HIF1A-AS2 or PD-L1 was confirmed by luciferase reporter assay. Murine xenograft model was established to investigate the role of HIF1A-AS2 in vivo.

RESULTS

HIF1A-AS2 was elevated in GC tissues and cell lines. Functional experiments showed that HIF1A-AS2 knockdown inhibited GC cell proliferation, migration, and invasion in vitro, as well as hindered tumor growth in vivo. Moreover, HIF1A-AS2 directly bound to miR-429 based on bioinformatics prediction and luciferase assay, and inhibition of miR-429 abolished the effects of HIF1A-AS2 knockdown on GC cells. Furthermore, miR-429 directly targeted PD-L1, and overexpression of miR-429 suppressed GC tumorigenesis via PD-L1. Besides that, PD-L1 also performed an oncogenic role in GC cell proliferation and metastasis. Additionally, HIF1A-AS2 could indirectly regulate PD-L1 expression via sponging miR-429.

CONCLUSION

HIF1A-AS2 is a dependable predictor of malignancy and prognosis in GC and functions as an oncogene to promote GC cell proliferation and metastasis by regulating miR-429/PD-L1 axis, indicating a new insight into the search for novel biomarkers and therapeutic strategies.

CircTP63 promotes cell proliferation and invasion by regulating EZH2 via sponging miR-217 in gallbladder cancer

Background

Gallbladder cancer (GBC) is the most common biliary tract malignancy and has a poor prognosis in patients with GBC. CircRNA TP63 (circTP63) has been implicated in cell proliferation and invasion in some tumor progress. The study aims to investigate the clinical significance and functional role of circTP63 expression in GBC.

Methods

The expression of circTP63 in GBC tissues or cells was detected by qRT-PCR and the association between circTP63 expression and prognosis of GBC patients was analyzed. CCK8 assay, flow cytometry analysis, transwell assay and in vivo studies were used to evaluate the cell proliferation and invasion abilities after circTP63 knockdown in GBC cells. Luciferase reporter assays and RNA pull-down assay were used to determine the correlation between circTP63 and miR-217 expression. Besides, western blot analysis was also performed.

Results

In the present study, we showed that circTP63 expression was upregulated in GBC tissues and cells. Higher circTP63 expression was associated with lymph node metastasis and short overall survival (OS) in patients with GBC. In vitro, knockdown of circTP63 significantly inhibited cell proliferation, cell cycle progression, migration and invasion abilities in GBC. Besides, we demonstrated that knockdown of circTP63 inhibited GBC cells Epithelial-Mesenchymal Transition (EMT) process. In vivo, knockdown of circTP63 inhibited tumor growth in GBC. Mechanistically, we demonstrated that circTP63 competitively bind to miR-217 and promoted EZH2 expression and finally facilitated tumor progression.

Conclusions

Our findings demonstrated that circTP63 sponged to miR-217 and regulated EZH2 expression and finally facilitated tumor progression in GBC. Thus, targeting circTP63 may be a therapeutic strategy for the treatment of GBC.

The Value of Circulating Circular RNA in Cancer Diagnosis, Monitoring, Prognosis, and Guiding Treatment

Liquid biopsy includes non-invasive analysis of circulating tumor-derived substances. It is a novel, innovative cancer screening tool that overcomes the limitations of current invasive tissue examinations in precision oncology. Circular RNA (circRNA) is a recent, novel, and attractive liquid biomarker showing stability, abundance, and high specificity in various diseases, especially in human cancers. This review focused on the emerging potential of human circRNA in body fluids as the liquid biopsy biomarkers for cancers and the methods used to detect the circRNA expression and summarized the construction of circRNA biomarkers in body fluids for treating human cancers and their limitations before they become part of routine clinical medicine. Furthermore, the future opportunities and challenges of translating circRNAs in liquid biopsy into clinical practices were explored.

Bladder mesenchymal stromal cell-derived exosomal miRNA-217 modulates bladder cancer cell survival through Hippo-YAP pathway

BACKGROUND

Donor cell-derived exosomes regulate recipient cell functions. The aim of this study was to investigate the effect of human normal bladder stromal cell (hBSC) derived exosomal miR-217 on bladder cell cancer proliferation and migration.

METHODS

Human BSCs were transfected with miR-217 mimic or inhibitor and hBSC-derived exosomes were isolated. Human bladder cancer cell lines (T24 and 5367) were co-cultured with hBSC-derived exosomal miR-217 mimic or inhibitor. Proliferation, migration, and apoptosis of the bladder cancer cells were assessed by Edu assay, Transwell migration assay, and Annexin V assay.

RESULTS

Expression of miR-217 was significantly higher in the T24 and 5367 cell lines (P < 0.01). Exosomal miR-217 mimic enhanced proliferation and migration of T24 and 5367 cells, but inhibited apoptosis of the cells (P < 0.01); in contrast, exosomal miR-217 inhibitor suppressed proliferation and migration but stimulated apoptosis of the two cancer cell lines (P < 0.01). Moreover, exosomal miR-217 mimic stimulated YAP and its target proteins including Cyr61, CTGF, and ANKRD1 (P < 0.01), and in contrast, exosomal miR-217 inhibitor suppressed YAP and its target proteins (P < 0.01).

CONCLUSION

These findings suggested that hBSC-derived exosomal miR-217 may act as oncogene in bladder cancer cells, and that Hippo-YAP signaling pathway maybe the target for miR-217 in the bladder cancer cell lines.

The distinct roles of exosomes in tumor-stroma crosstalk within gastric tumor microenvironment

Gastric cancer (GC) development is a complex process displaying polytropic cell and molecular landscape within gastric tumor microenvironment (TME). Stromal cells in TME, including fibroblasts, endothelial cells, mesenchymal stem cells, and various immune cells, support tumor growth, metastasis, and recurrence, functioning as the soil for gastric tumorigenesis. Importantly, exosomes secreted by either stromal cells or tumor cells during tumor-stroma crosstalk perform as crucial transporter of agents including RNAs and proteins for cell-cell communication in GC pathogenesis. Therefore, given the distinct roles of exosomes secreted by various cell types in GC TME, increasing evidence has indicated that exosomes present as new biomarkers for GC diagnosis and prognosis and shed light on novel approaches for GC treatment.

Identification of differentially expressed microRNAs in primary esophageal achalasia by next-generation sequencing

Molecular knowledge regarding the primary esophageal achalasia is essential for the early diagnosis and treatment of this neurodegenerative motility disorder. Therefore, there is a need to find the main microRNAs (miRNAs) contributing to the mechanisms of achalasia. This study was conducted to determine some patterns of deregulated miRNAs in achalasia. This case-control study was performed on 52 patients with achalasia and 50 nonachalasia controls. The miRNA expression profiling was conducted on the esophageal tissue samples using the next-generation sequencing (NGS). Differential expression of miRNAs was analyzed by the edgeR software. The selected dysregulated miRNAs were additionally confirmed using the quantitative reverse transcription polymerase chain reaction (qRT-PCR). Fifteen miRNAs were identified that were significantly altered in the tissues of the patients with achalasia. Among them, three miRNAs including miR-133a-5p, miR-143-3p, and miR-6507-5p were upregulated. Also, six miRNAs including miR-215-5p, miR-216a-5p, miR-216b-5p, miR-217, miR-7641 and miR-194-5p were downregulated significantly. The predicted targets for the dysregulated miRNAs showed significant disease-associated pathways like neuronal cell apoptosis, neuromuscular balance, nerve growth factor signaling, and immune response regulation. Further analysis using qRT-PCR showed significant down-regulation of hsa-miR-217 (p-value = 0.004) in achalasia tissue. Our results may serve as a basis for more future functional studies to investigate the role of candidate miRNAs in the etiology of achalasia and their application in the diagnosis and probably treatment of the disease.

Targeting WASF3 Signaling in Metastatic Cancer

Increasing evidence indicates that cancer metastasis is regulated by specific genetic pathways independent of those controlling tumorigenesis and cancer growth. WASF3, a Wiskott–Aldrich syndrome protein family member, appears to play a major role not only in the regulation of actin cytoskeleton dynamics but also in cancer cell invasion/metastasis. Recent studies have highlighted that WASF3 is a master regulator and acts as a pivotal scaffolding protein, bringing the various components of metastatic signaling complexes together both spatially and temporally. Herein, targeting WASF3 at the levels of transcription, protein stability, and phosphorylation holds great promise for metastasis suppression, regardless of the diverse genetic backgrounds associated with tumor development. This review focuses on the critical and distinct contributions of WASF3 in the regulation of signal pathways promoting cancer cell invasion and metastasis.

MicroRNA-217: A regulator of human cancer

As highly conserved non-coding RNAs of approximately 18-24 nucleotides, microRNAs (miRNAs) regulate the expression of target genes. Multiple studies have demonstrated that miRNAs participate in the regulation of human cancer. MircoRNA-217 (miR-217) participates in the regulation of various tumors by specifically binding target genes and post-transcriptional regulation. In recent years, there have been numerous reports about miR-217 in tumor progression. MiR-217 is known mainly as a tumor suppressor, although some studies have shown that it functions as an oncomiR. Here, we review the current research related to miR-217, including its role in tumor progression and the molecular mechanisms.

Serum MicroRNA Signatures in Recovery From Acute and Chronic Liver Injury and Selection for Liver Transplantation

We previously demonstrated a distinct hepatic microRNA (miRNA) signature (down-regulation of miRNA-23a, -150, - 200b, -503, and -663 and up-regulation of miRNA-20a) is associated with successful regeneration in auxiliary liver transplantation (ALT). This study aimed to evaluate whether the serum expression of this regeneration-linked miRNA signature is associated with clinical outcomes in acute and chronic liver disease. These were represented by patients with acetaminophen-induced acute liver failure (ALF; n = 18) and patients with hepatitis C virus (HCV) undergoing treatment with direct-acting antivirals (n = 56), respectively. Patients were grouped depending on their clinical outcome. Global serum miRNA expression was analyzed using polymerase chain reaction (PCR) arrays and selected miRNA expression using targeted PCR. We demonstrate that specific regeneration-linked miRNAs discriminate outcomes in both clinical scenarios. We further show that miRNA-20a, -23a, -150, -200b, -503, and -663 undergo concordant changes in expression in 3 distinct clinical settings: liver regeneration accompanying successful ALT, clinical recovery after ALF, and clinical recompensation after cure of HCV. This miRNA signature represents a potentially novel biomarker to predict outcome and optimize patient selection for liver transplantation in both acute and chronic liver disease.

Hsa-miR-217 Inhibits the Proliferation, Migration, and Invasion in Non-small Cell Lung Cancer Cells Via Targeting SIRT1 and P53/KAI1 Signaling

Background:

Brain metastasis is a major cause of cancer death in patients with lung cancer. Sirtuin 1 and hsa-miR-217 have been identified to mediate the development of non-small cell lung cancer.

Aims:

To investigate the roles of hsa-miR-217, its target sirtuin 1, and the P53/KAI1 axis in the brain metastasis from non-small cell lung cancer.

Study Design:

Cell culture study.

Methods:

Human pulmonary adenocarcinoma brain metastasis cell line PC-14/B were incubated and treated with constructed lentiviral plasmids expressing miR-217 and/or sirtuin 1. BEAS-2B cell line was used as a control. The targeted regulation of miR-217 to sirtuin 1was examined using a dual-luciferase reporter assay. Cell proliferation, migration, invasion, and related protein expression were detected to examine the effect of the miR-217/sirtuin 1 expression on metastasis.

Results:

PC-14/B cells expressed higher sirtuin 1 and lower P53 and KAI1 compared with BEAS-2B control cells (p<0.05). Sirtuin 1 was a direct target of miR-217. MiR-217 expression suppressed PC-14/B cell invasion (p=0.004), migration (p=0.001), and proliferation (p<0.05), whereas sirtuin 1 overexpression reversed all processes. sirtuin 1 expression inhibited P53, KAI1/CD82, matrix metalloproteinase-9, and β-catenin but upregulated E-cadherin protein. MiR-217 overexpression induced reverse changes.

Conclusion:

Hsa-miR-217 and its target sirtuin 1 acted as metastasis suppressor and promoter gene in non-small cell lung cancer, respectively. The hsa-miR-217/sirtuin 1/P53/KAI1 metastasis regulatory pathway showed novel and crucial roles in brain metastasis from non-small cell lung cancer. This axis might be a potential target for the treatment of brain metastasis of lung cancer.

Influence of miR-376c-3p/SYF2 Axis on the Progression of Gastric Cancer

MicroRNA-376c-3p was previous reported to have a crucial role in the progression of human cancer. This study was aimed to investigate the influence of microRNA-376c-3p on the proliferation and migration of human gastric cancer cells and the associated mechanism. We explored the expression of microRNA-376c-3p in gastric cancer cells using reverse transcription-quantitative polymerase chain reaction. Also, we analyzed the association and biological significance of microRNA-376c-3p and SYF2 pre-mRNA-splicing factor in gastric cancer. MicroRNA-376c-3p expression was found downregulated in gastric cancer cell lines compared to the normal cell line. MicroRNA-376c-3p directly targeted SYF2 and reduced SYF2 expression. Overexpression of microRNA-376c-3p inhibits gastric cancer cell proliferation and migration. Besides that, overexpression of SYF2 abrogates the inhibitory influences on gastric cancer cell behaviors caused by microRNA-376c-3p mimic. These results showed that microRNA-376c-3p inhibits the proliferation and migration of gastric cancer cells via targeting SYF2.

Identification of key genes and long non-coding RNA associated ceRNA networks in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. Although multiple efforts have been made to understand the development of HCC, morbidity, and mortality rates remain high. In this study, we aimed to discover the mRNAs and long non-coding RNAs (lncRNAs) that contribute to the progression of HCC. We constructed a lncRNA-related competitive endogenous RNA (ceRNA) network to elucidate the molecular regulatory mechanism underlying HCC.

Methods

A microarray dataset (GSE54238) containing information about both mRNAs and lncRNAs was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) and lncRNAs (DElncRNAs) in tumor tissues and non-cancerous tissues were identified using the limma package of the R software. The miRNAs that are targeted by DElncRNAs were predicted using miRcode, while the target mRNAs of miRNAs were retrieved from miRDB, miRTarBas, and TargetScan. Functional annotation and pathway enrichment of DEGs were performed using the EnrichNet website. We constructed a protein–protein interaction (PPI) network of DEGs using STRING, and identified the hub genes using Cytoscape. Survival analysis of the hub genes and DElncRNAs was performed using the gene expression profiling interactive analysis database. The expression of molecules with prognostic values was validated on the UALCAN database. The hepatic expression of hub genes was examined using the Human Protein Atlas. The hub genes and DElncRNAs with prognostic values as well as the predictive miRNAs were selected to construct the ceRNA networks.

Results

We found that 10 hub genes (KPNA2, MCM7, CKS2, KIF23, HMGB2, ZWINT, E2F1, MCM4, H2AFX, and EZH2) and four lncRNAs (FAM182B, SNHG6, SNHG1, and SNHG3) with prognostic values were overexpressed in the hepatic tumor samples. We also constructed a network containing 10 lncRNA–miRNA–mRNA pathways, which might be responsible for regulating the biological mechanisms underlying HCC.

Conclusion

We found that the 10 significantly overexpressed hub genes and four lncRNAs were negatively correlated with the prognosis of HCC. Further, we suggest that lncRNA SNHG1 and the SNHG3-related ceRNAs can be potential research targets for exploring the molecular mechanisms of HCC.

Exosomal circRNAs: biogenesis, effect and application in human diseases

Exosomes have emerged as critical mediators of intercellular communication, both locally and systemically, by regulating a diverse range of biological processes between cells. Circular RNA (circRNA) is a novel member of endogenous noncoding RNAs with widespread distribution and diverse cellular functions. Recently, circular RNAs have been identified for their enrichment and stability in exosomes. In this review, we outline the origin, biogenesis and function of exosomal circRNAs as well as their roles in various diseases. Although their precise roles and mechanisms of gene regulation remain largely elusive, exosomal circRNAs have potential applications as disease biomarkers and novel therapeutic targets.

An integrated prediction model of recurrence in endometrial endometrioid cancers

Objectives: Endometrial cancer incidence and mortality are rising in the US. Disease recurrence has been shown to have a significant impact on mortality. However, to date, there are no accurate and validated prediction models that would discriminate which individual patients are likely to recur. Reliably predicting recurrence would be of benefit for treatment decisions following surgery. We present an integrated model constructed with comprehensive clinical, pathological and molecular features designed to discriminate risk of recurrence for patients with endometrioid endometrial adenocarcinoma. Subjects and methods: A cohort of endometrioid endometrial cancer patients treated at our institution was assembled. Clinical characteristics were extracted from patient charts. Primary tumors from these patients were obtained and total tissue RNA extracted for RNA sequencing. A prediction model was designed containing both clinical characteristics and molecular profiling of the tumors. The same analysis was carried out with data derived from The Cancer Genome Atlas for replication and external validation. Results: Prediction models derived from our institutional data predicted recurrence with high accuracy as evidenced by areas under the curve approaching 1. Similar trends were observed in the analysis of TCGA data. Further, a scoring system for risk of recurrence was devised that showed specificities as high as 81% and negative predictive value as high as 90%. Lastly, we identify specific molecular characteristics of patient tumors that may contribute to the process of disease recurrence. Conclusion: By constructing a comprehensive model, we are able to reliably predict recurrence in endometrioid endometrial cancer. We devised a clinically useful scoring system and thresholds to discriminate risk of recurrence. Finally, the data presented here open a window to understanding the mechanisms of recurrence in endometrial cancer.

Dual Tumor Suppressor and Tumor Promoter Action of Sirtuins in Determining Malignant Phenotype

Sirtuins (SIRTs), class III histone deacetylases, are differentially expressed in several human cancers, where they display both oncogenic and tumor-suppressive properties depending on cellular context and experimental conditions. SIRTs are involved in many important biological processes and play a critical role in cancer initiation, promotion, and progression. A growing body of evidence indicates the involvement of SIRTs in regulating three important tumor processes: epithelial-to-mesenchymal transition (EMT), invasion, and metastasis. Many SIRTs are responsible for cellular metabolic reprogramming and drug resistance by inactivating cell death pathways and promoting uncontrolled proliferation. In this review, we summarize current knowledge on the role of SIRTs in cancer and discuss their puzzling dual function as tumor suppressors and tumor promoters, important for the future development of novel tailored SIRT-based cancer therapies.

Regulat-INGs in tumors and diseases: Focus on ncRNAs

ING family genes (Inhibitor of Growth) are tumor suppressor genes that play a vital role in cell homeostasis. It has been shown that their expression is lost or diminished in many cancers and other diseases. The main mechanisms by which they are regulated in oncogenesis have not yet been fully elucidated. The involvement of non-coding RNAs (ncRNAs) and in particular microRNAs (miRNAs) in post-transcriptional gene regulation is well established. miRNAs are short sequences (18-25 nucleotides) that can bind to the 3 'UTR sequence of the targeted messenger RNA (mRNA), leading to its degradation or translational repression. Interactions between the ING family and miRNAs have been described in some cancers but also in other diseases. The involvement of miRNAs in ING family regulation opens up new fields of investigation, particularly for targeted therapies. In this review, we will summarize the regulatory mechanisms at the RNA and protein level of the ING family and focus on the interactions with ncRNAs.

MiR-217 promotes cell proliferation and osteogenic differentiation of BMSCs by targeting DKK1 in steroid-associated osteonecrosis

MicroRNAs (miRNAs) have recently been recognized to play an important role in bone-associated diseases. This study aims to explore the expression profile and biological function of miR-217, which is known to be related to tumor cell proliferation and migration, to the proliferation and osteogenic differentiation of MSCs from the patients with steroid-associated osteonecrosis (ONFH). Bone marrow was obtained from the proximal femur of 10 patients with ONFH and 10 patients with femoral neck fractures. Bone marrow-derived mesenchymal stem cells (MSCs) were isolated and cultured. The expression profile, biological function of miR-217 and the interaction between miR-217 and DKK1 were assayed using cell viability measurement, western blot, Real-time PCR, luciferase reporter assay, Alizarin Red S (ARS) staining. We noted that the expression level of miR-217 was significantly decreased in the ONFH samples compared to the control samples (P < 0.0001). By targeting DKK1, miR-217 promoted nuclear translocation of β-catenin, increased expression of RUNX2, COL1A1 and obviously promoted the proliferation and differentiation of MSCs. Restoring the expression of DKK1 in the MSCs partially reversed the role of miR-217. These findings suggest that miR-217 promotes cell proliferation and osteogenic differentiation by inhibiting DKK1 during the development of steroid-associated osteonecrosis.

Impact of miRNA-mRNA Profiling and Their Correlation on Medulloblastoma Tumorigenesis

Medulloblastoma (MB) is a clinically challenging, childhood brain tumor with a diverse genetic makeup and differential miRNA profile. Aiming to identify deregulated miRNAs in MB, the miRNA expression profile of human MB samples was compared to that of normal cerebellar tissues. As a result, 8 upregulated and 64 downregulated miRNAs were identified in MB samples. Although various algorithms have been developed to predict the interaction between miRNA-mRNA pairs, the complexity and fidelity of miRNA-mRNA remain a concern. Therefore, to identify the signatures of miRNA-mRNA interactions essential for MB pathogenesis, miRNA profiling, RNA sequencing, and ingenuity pathway analysis (IPA) were performed in the same primary human MB samples. Further, when miR-217 was inhibited, a significant upregulation of predicted target genes SIRT1, ROBO1, FOXO3, and SMAD7 in HDMB03 cells was observed, confirming the validity of our approach. Functional analysis revealed that the inhibition of miR-217 in HDMB03 cells suppresses colony formation, migration, invasion, promoted apoptosis, and arrested cell population in S phase, indicating that manipulation of miR-217 may have a therapeutic potential for MB patients. Therefore, our study provides an essential platform for future investigations of specific miRNAs responsible for MB pathogenesis.

The tumor suppressor role of miR-155-5p in gastric cancer

Gastric cancer (GC) is the fifth most common type of malignant tumor worldwide and the most common cause of cancer-associated mortality in China. Recent studies revealed that microRNAs (miRNAs) function in the pathogenesis of GC, and that miR-155-5p expression is downregulated in GC tissues. However, the function of miR-155-5p has not been fully identified. In the present study, it was demonstrated that overexpression of miR-155-5p inhibited GC-cell proliferation and promoted apoptosis, while downregulation of miR-155-5p promoted GC-cell proliferation and decreased the cisplatin sensitivity of GC cells. Mitogen-activated protein kinase kinase kinase 10 was demonstrated to be a potential target gene of miR-155-5p. In conclusion, an antitumor role of miR-155-5p in gastric cancer was suggested.

Kallikrein-related peptidases and associated microRNAs as promising prognostic biomarkers in gastrointestinal malignancies

Gastrointestinal (GI) malignancies represent a wide spectrum of diseases of the GI tract and its accessory digestive organs, including esophageal (EC), gastric (GC), hepatocellular, pancreatic (PC) and colorectal cancers (CRC). Malignancies of the GI system are responsible for nearly 30% of cancer-related morbidity and approximately 40% of cancer-related mortality, worldwide. For this reason, the discovery of novel prognostic biomarkers that can efficiently provide a better prognosis, risk assessment and prediction of treatment response is an imperative need. Human kallikrein-related peptidases (KLKs) are a subgroup of trypsin and chymotrypsin-like serine peptidases that have emerged as promising prognosticators for many human types of cancer, being aberrantly expressed in cancerous tissues. The aberrant expression of KLKs in human malignancies is often regulated by KLK/microRNAs (miRNAs) interactions, as many miRNAs have been found to target KLKs and therefore alter their expression levels. The biomarker utility of KLKs has been elucidated not only in endocrine-related human malignancies, including those of the prostate and breast, but also in GI malignancies. The main purpose of this review is to summarize the existing information regarding the prognostic significance of KLKs in major types of GI malignancies and highlight the regulatory role of miRNAs on the expression levels of KLKs in these types of cancer.

HOTAIR enhanced paclitaxel and doxorubicin resistance in gastric cancer cells partly through inhibiting miR-217 expression

Drug resistance is a big obstacle for clinical anti-tumor treatment outcome. However, the role of HOTAIR in drug resistance in gastric cancer (GC) remains unknown. In this study, we showed that overexpression of HOTAIR enhanced paclitaxel and doxorubicin resistance in GC cells. Furthermore, the expression of HOTAIR was upregulated in GC tissues and higher expression of HOTAIR was associated with late stage. In addition, we showed that miR-217 expression was lower in GC tissues compared with the paired non-tumour tissues and downregulated expression of miR-217 was correlated with late stage. Interestingly, the expression of miR-217 was negatively correlated with HOTAIR expression in GC tissues. Ectopic expression of HOTAIR increased GC cell proliferation, cell cycle, and migration. Elevated expression of HOTAIR suppressed miR-217 expression and enhanced GPC5 and PTPN14 expression. Furthermore, we demonstrated that overexpression of miR-217 suppressed paclitaxel and doxorubicin resistance in GC cells. Ectopic expression of HOTAIR promoted drug resistance and increased GC cell proliferation, cell cycle, and migration by targeting miR-217. These data suggested that overexpression of HOTAIR enhanced paclitaxel and doxorubicin resistance in GC cells through inhibiting miR-217 expression.

Long non-coding RNA HOXD-AS1 promotes tumor progression and predicts poor prognosis in colorectal cancer

Mounting evidence has indicated that long non-coding RNAs (lncRNA) serve important roles in tumor development. Previous studies have demonstrated that the lncRNA HOXD cluster antisense RNA 1 (HOXD-AS1) promotes tumor progression in numerous types of cancer; however, the role of HOXD-AS1 in colorectal cancer (CRC) remains unclear. In the present study, the expression levels of HOXD-AS1 were detected in CRC tissues and cell lines using quantitative polymerase chain reaction. In addition, the biological effects of HOXD-AS1 on CRC were evaluated in vitro by cell counting kit-8, colony formation and Transwell assays, and in vivo by tumorigenesis and metastasis assays. The results demonstrated that HOXD-AS1 was upregulated in CRC tissues and cell lines, and that overexpression of HOXD-AS1 was associated with poor prognosis in patients with CRC. Furthermore, knockdown of HOXD-AS1 inhibited cell proliferation, cell invasion, epithelial-mesenchymal transition and stem cell formation in vitro, as well as tumor growth and metastasis in vivo. Mechanistically, HOXD-AS1 functioned as a competing endogenous RNA for miR-217. In conclusion, the present study demonstrated that HOXD-AS1 may promote CRC progression and metastasis by competing for miR-217. In addition, HOXD-AS1 may be considered an indicator of prognosis in patients with CRC.

Exosomal circRNA_100284 from arsenite-transformed cells, via microRNA-217 regulation of EZH2, is involved in the malignant transformation of human hepatic cells by accelerating the cell cycle and promoting cell proliferation

Intercellular communication between malignant cells and neighboring nonmalignant cells is involved in carcinogenesis. In the progression of carcinogenesis, exosomes are messengers for intercellular communication. Circular RNAs (circRNAs) are noncoding RNAs with functions that include regulation of the cell cycle and proliferation. However, the functions of exosomal circRNAs are not clear. The present research aimed to determine whether circRNAs secreted from arsenite-transformed human hepatic epithelial (L-02) cells are transferred into normal L-02 cells and become functionally active in the normal cells. The results showed that circRNA_100284 is involved in the malignant transformation of L-02 cells induced by arsenite. The medium from transformed L-02 cells induced upregulation of circRNA_100284, accelerated the cell cycle, and promoted proliferation of normal L-02 cells. Transformed cells transferred circRNA_100284 into normal L-02 cells via exosomes and led to the malignant transformation of the non-transformed cells. Knockdown of circRNA_100284, which reduced circRNA_100284 levels in exosomes derived from transformed L-02 cells, blocked the accelerated cell cycle and reduced proliferation and malignancy. In addition, in normal L-02 cells, exosomal circRNA_100284 derived from arsenite-transformed L-02 cells induced acceleration of the cell cycle and promoted proliferation via acting as a sponge of microRNA-217. Further, exosomal circRNA_100284 was upregulated in the sera of people exposed to arsenite. Thus, exosomes derived from transformed L-02 cells transferred circRNA_100284 to surrounding cells, which induced an accelerated cell cycle and promoted proliferation of normal liver cells and led to the malignant transformation of the non-transformed cells. The findings support the concept that exosomal circRNAs are involved in cell–cell communication during carcinogenesis induced by arsenite.

MicroRNA-125a-5p inhibits invasion and metastasis of gastric cancer cells by targeting BRMS1 expression

Accumulating studies have demonstrated microRNAs (miRNAs/miRs) have an important role in multiple processes of human malignant tumor development and progression. Decreased expression of miR-125a-5p has been observed in several types of cancer, including gastric cancer (GC). However, the mechanism and exact function of miR-125a-5p in GC have not been largely elucidated. In the present study, reverse transcription-quantitative polymerase chain reaction indicated that the expression of miR-125a-5p was downregulated in GC tissues and cell lines compared with matched normal tissues (P<0.01) and normal gastric mucosa cell lines (P<0.01), respectively. Moreover, clinical pathological characteristics and Kaplan-Meier analysis indicated that a low expression of miR-125a-5p was not only associated with lymph metastasis, peritoneal dissemination and advanced tumor-node metastasis stage but also affected the prognosis of GC patients. Compared with miR-control-transfected GC cells, markedly decreased migration and invasion was observed in GC cells that overexpress miR-125a-5p. By contrast, increased metastasis and invasion were observed in miR-125a-5p-knocked down cells compared with the control. Furthermore, luciferase reporter assays indicated that breast cancer metastasis suppressor 1 (BRMS1) was a direct target of miR-125a-5p. Notably, a positive correlation between the levels of BRMS1 and miR-125a-5p in GC tissues was observed, and BRMS1 expression was indicated to be regulated by miR-125a-5p in GC cells. In conclusion, miR-125a-5p may act as a tumor suppressor by targeting the metastasis-inhibitory gene, BRMS1. The data suggesting that BRMS1 is a potential target gene of miR-125a-5p, may provide novel insight into miRNA regulation of human gene expression, and a useful target for gene therapy of GC.

The relationship between EZH2 expression and microRNA-31 in colorectal cancer and the role in evolution of the serrated pathway

Polycomb group protein enhancer of zeste homolog 2 (EZH2) is a methyltransferase that correlates with the regulation of invasion and metastasis and is overexpressed in human cancers such as colorectal cancer. MicroRNA-31 (miR-31) plays an oncogenic role and is associated with BRAF mutation and poor prognosis in colorectal cancer. EZH2 is functionally considered to suppress miR-31 expression in human cancers; however, no study has reported its relationship with colon cancer. We therefore evaluated EZH2 expression using immunohistochemistry and assessed miR-31 and epigenetic alterations using 301 colorectal carcinomas and 207 premalignant lesions. Functional analysis was performed to identify the association between EZH2 and miR-31 using cancer cell lines. In the current study, negative, weak, moderate, and strong EZH2 expressions were observed in 15%, 19%, 25%, and 41% of colorectal cancers, respectively. EZH2 was inversely associated with miR-31 (P < 0.0001), independent of clinicopathological and molecular features. In a multivariate stage-stratified analysis, high EZH2 expression was related to favorable prognosis (P = 0.0022). Regarding premalignant lesions, negative EZH2 expression was frequently detected in sessile serrated adenomas/polyps (SSA/Ps) (76%; P < 0.0001) compared with hyperplastic polyps, traditional serrated adenomas, and non-serrated adenomas (25–36%). Functional analysis demonstrated that the knockdown of EZH2 increased miR-31 expression. In conclusion, an inverse association was identified between EZH2 and miR-31 in colorectal cancers. Our data also showed that upregulation of EZH2 expression may be rare in SSA/Ps. These results suggest that EZH2 suppresses miR-31 in colorectal cancer and may correlate with differentiation and evolution of serrated pathway.

MicroRNA-4465 suppresses tumor proliferation and metastasis in non-small cell lung cancer by directly targeting the oncogene EZH2

MicroRNA-26 (miR-26) has been reported to be connected with tumor progression. MicroRNA-4465 (miR-4465) was one member of miR-26 family, however, the role of miR-4465 in non-small cell lung cancer (NSCLC) was unknown. This study was aimed to explore the function of miR-4465 and investigate whether miR-4465 can be a potential target for treating human NSCLC. QRT-PCR was applied to evaluate the miR-4465 expression levels in NSCLC cells. Then, we demonstrated the role of miR-4465 in NSCLC cells biological characteristics through detecting proliferation, migration and invasion. Luciferase reporter assay and TargetScan were applied to explore the potential target gene of miR-4465. In this study, we found that the miR-4465 expression levels in NSCLC cell lines were significantly reduced when compared to the normal human bronchial epithelial cell lines. And, over expression of miR-4465 could restrain the proliferation, migration and invasion of NSCLC. Moreover, MiR-4465 reduced EZH2 protein expression through the binding sites in 3' -UTR of the EZH2 mRNA, indicating EZH2 may be a direct target gene of miR-4465. Conclusively, miR-4465 suppressed cancer cells proliferation and metastasis by directly targeting the oncogene EZH2 and it may serve as a new potential therapeutic target in NSCLC.

Post-transcriptional Regulation of Genes Related to Biological Behaviors of Gastric Cancer by Long Noncoding RNAs and MicroRNAs

Noncoding RNAs play critical roles in regulating protein-coding genes and comprise two major classes: long noncoding RNAs (lncRNAs) and microRNAs (miRNAs). LncRNAs regulate gene expression at transcriptional, post-transcriptional, and epigenetic levels via multiple action modes. LncRNAs can also function as endogenous competitive RNAs for miRNAs and indirectly regulate gene expression post-transcriptionally. By binding to the 3'-untranslated regions (3'-UTR) of target genes, miRNAs post-transcriptionally regulate gene expression. Herein, we conducted a review of post-transcriptional regulation by lncRNAs and miRNAs of genes associated with biological behaviors of gastric cancer.

miR-217-5p induces apoptosis by directly targeting PRKCI, BAG3, ITGAV and MAPK1 in colorectal cancer cells

Apoptosis is a genetically directed process of programmed cell death. A variety of microRNAs (miRNAs), endogenous single-stranded non-coding RNAs of about 22 nucleotides in length have been shown to be involved in the regulation of the intrinsic or extrinsic apoptotic pathways. There is increasing evidence that the aberrant expression of miRNAs plays a causal role in the development of diseases such as cancer. This makes miRNAs promising candidate molecules as therapeutic targets or agents. MicroRNA (miR)-217-5p has been implicated in carcinogenesis of various cancer entities, including colorectal cancer. Here, we analyzed the pro-apoptotic potential of miR-217-5p in a variety of colorecatal cancer cell lines showing that miR-217-5p mimic transfection led to the induction of apoptosis causing the breakdown of mitochondrial membrane potential, externalization of phosphatidylserine, activation of caspases and fragmentation of DNA. Furthermore, elevated miR-217-5p levels downregulated mRNA and protein expression of atypical protein kinase c iota type I (PRKCI), BAG family molecular chaperone regulator 3 (BAG3), integrin subunit alpha v (ITGAV) and mitogen-activated protein kinase 1 (MAPK1). A direct miR-217-5p mediated regulation to those targets was shown by repressed luciferase activity of reporter constructs containing the miR-217-5p binding sites in the 3' untranslated region. Taken together, our observations have uncovered the apoptosis-inducing potential of miR-217-5p through its regulation of multiple target genes involved in the ERK-MAPK signaling pathway by regulation of PRKCI, BAG3, ITGAV and MAPK1.

miR-217 targeting DKK1 promotes cancer stem cell properties via activation of the Wnt signaling pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies and exhibits heterogeneity in terms of clinical outcomes and biological activities. Emerging evidence has demonstrated that cancer stem cells (CSCs) play important roles in the tumorigenesis and progression of HCC. However, the molecular mechanisms underlying the stemness maintenance of CSCs remain largely unknown. In the present study, through real-time PCR, western blotting, luciferase assays, RNA immunoprecipitation, and in vitro and in vivo assays, we demonstrated that miR-217 expression was markedly increased in HCC tissues and cells. Overexpression of miR-217 promoted, while silencing miR-217 suppressed, the fraction of the side population and the expression of cancer stem cell factors in vitro and tumorigenicity in vivo in HCC cells. Our findings further demonstrated that miR-217 promoted the CSC-like phenotype via dickkopf-1 (DKK1) targeting, resulting in constitutive activation of Wnt signaling. Moreover, the stimulatory effects of miR-217 on stem cell properties and Wnt signaling were antagonized by the upregulation of DKK1 in miR-217-overexpressing cells. Conversely, the inhibitory effects of silencing miR-217 on stem cell properties and Wnt signaling were reversed by the downregulation of DKK1 in miR-217-downregulated cells. Therefore, our results indicate that miR-217 plays a vital role in the CSC-like phenotypes of HCC cells and may be used as a potential therapeutic target against HCC.

Prognostic value of microRNAs in gastric cancer: a meta-analysis

BACKGROUND

Previous articles have reported that expression levels of microRNAs (miRNAs) are associated with survival time of patients with gastric cancer (GC). A systematic review and meta-analysis was performed to study the outcome of it.

DESIGN

Meta-analysis.

METHODS

English studies estimating expression levels of miRNAs with any of survival curves in GC were identified up till March 19, 2017 through performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews by two authors independently. The pooled hazard ratios (HR) with 95% confidence intervals (CI) were used to estimate the correlation between miRNA expression and overall survival (OS).

RESULTS

Sixty-nine relevant articles about 26 miRNAs with 6148 patients were ultimately included. GC patients with high expression of miR-20b (HR=2.38, 95%CI=1.16-4.87), 21 (HR=1.77, 95%CI=1.01-3.08), 106b (HR=1.84, 95%CI=1.15-2.94), 196a (HR=2.66, 95%CI=1.94-3.63), 196b (HR=1.67, 95%CI=1.38-2.02), 214 (HR=1.84, 95%CI=1.27-2.67) or low expression of miR-125a (HR=2.06, 95%CI=1.26-3.37), 137 (HR=3.21, 95%CI=1.68-6.13), 141 (HR=2.47, 95%CI=1.34-4.56), 145 (HR=1.62, 95%CI=1.07-2.46), 146a (HR=2.60, 95%CI=1.63-4.13), 206 (HR=2.85, 95%CI=1.73-4.70), 218 (HR=2.61, 95%CI=1.74-3.92), 451 (HR=1.73, 95%CI=1.19-2.52), 486-5p (HR=2.45, 95%CI=1.65-3.65), 506 (HR=2.07, 95%CI=1.33-3.23) have significantly poor OS (P<0.05).

CONCLUSIONS

In summary, miR-20b, 21, 106b, 125a, 137, 141, 145, 146a, 196a, 196b, 206, 214, 218, 451, 486-5p and 506 demonstrate significantly prognostic value. Among them, miR-20b, 125a, 137, 141, 146a, 196a, 206, 218, 486-5p and 506 are strong biomarkers of prognosis in GC.

Identifying the miRNA signature associated with survival time in patients with lung adenocarcinoma using miRNA expression profiles

Lung adenocarcinoma is a multifactorial disease. MicroRNA (miRNA) expression profiles are extensively used for discovering potential theranostic biomarkers of lung cancer. This work proposes an optimized support vector regression (SVR) method called SVR-LUAD to simultaneously identify a set of miRNAs referred to the miRNA signature for estimating the survival time of lung adenocarcinoma patients using their miRNA expression profiles. SVR-LUAD uses an inheritable bi-objective combinatorial genetic algorithm to identify a small set of informative miRNAs cooperating with SVR by maximizing estimation accuracy. SVR-LUAD identified 18 out of 332 miRNAs using 10-fold cross-validation and achieved a correlation coefficient of 0.88 ± 0.01 and mean absolute error of 0.56 ± 0.03 year between real and estimated survival time. SVR-LUAD performs well compared to some well-recognized regression methods. The miRNA signature consists of the 18 miRNAs which strongly correlates with lung adenocarcinoma: hsa-let-7f-1, hsa-miR-16-1, hsa-miR-152, hsa-miR-217, hsa-miR-18a, hsa-miR-193b, hsa-miR-3136, hsa-let-7g, hsa-miR-155, hsa-miR-3199-1, hsa-miR-219-2, hsa-miR-1254, hsa-miR-1291, hsa-miR-192, hsa-miR-3653, hsa-miR-3934, hsa-miR-342, and hsa-miR-141. Gene ontology annotation and pathway analysis of the miRNA signature revealed its biological significance in cancer and cellular pathways. This miRNA signature could aid in the development of novel therapeutic approaches to the treatment of lung adenocarcinoma.

Prognostic role of microRNAs in human gastrointestinal cancer: A systematic review and meta-analysis

BACKGROUND

Gastrointestinal cancers (GICs) mainly including esophageal, gastric and colorectal cancer, are the most common cause of cancer-related death and lead into high mortality worldwide. We performed this systematic review and meta-analysis to elucidate relationship between multiple microRNAs (miRs) expression and survival of GIC patients.

METHODS

We searched a wide range of database. Fixed-effects and random-effects models were used to calculate the pooled hazard ratio values of overall survival and disease free survival. In addition, funnel plots were used to qualitatively analyze the publication bias and verified by Begg's test while it seems asymmetry.

RESULTS

60 studies involving a total of 6225 patients (1271 with esophageal cancer, 3467 with gastric cancer and 1517 with colorectal cancer) were included in our meta-analysis. The pooled hazard ratio values of overall survival related to different miRs expression in esophageal, gastric, colorectal and gastrointestinal cancer were 2.10 (1.78-2.49), 2.02 (1.83-2.23), 2.54 (2.14-3.02) and 2.15 (1.99-2.31), respectively. We have identified a total of 59 miRs including 23 significantly up-regulated expression miRs (miR-214, miR-17, miR-20a, miR-200c, miR-107, miR-27a, etc.) and 36 significantly down-regulated expression miRs (miR-433, let-7g, miR-125a-5p, miR-760, miR-206, miR-26a, miR-200b, miR-185, etc.) correlated with poor prognosis in GIC patients. Moreover, 35 of them revealed mechanisms.

CONCLUSION

Overall, specific miRs are significantly associated with the prognosis of GIC patients and potentially eligible for the prediction of patients survival. It also provides a potential value for clinical decision-making development and may serve as a promising miR-based target therapy waiting for further elucidation.

Role of ARPC2 in Human Gastric Cancer

Gastric cancer continues to be the second most frequent cause of cancer deaths worldwide. However, the exact molecular mechanisms are still unclear. Further research to find potential targets for therapy is critical and urgent. In this study, we found that ARPC2 promoted cell proliferation and invasion in the human cancer cell line MKN-28 using a cell total number assay, MTT (3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay, cell colony formation assay, migration assay, invasion assay, and wound healing assay. For downstream pathways, CTNND1, EZH2, BCL2L2, CDH2, VIM, and EGFR were upregulated by ARPC2, whereas PTEN, BAK, and CDH1 were downregulated by ARPC2. In a clinical study, we examined the expression of ARPC2 in 110 cases of normal human gastric tissues and 110 cases of human gastric cancer tissues. ARPC2 showed higher expression in gastric cancer tissues than in normal gastric tissues. In the association analysis of 110 gastric cancer tissues, ARPC2 showed significant associations with large tumor size, lymph node invasion, and high tumor stage. In addition, ARPC2-positive patients exhibited lower RFS and OS rates compared with ARPC2-negative patients. We thus identify that ARPC2 plays an aneretic role in human gastric cancer and provided a new target for gastric cancer therapy.

let-7b and let-7c microRNAs promote histone H2B ubiquitylation and inhibit cell migration by targeting multiple components of the H2B deubiquitylation machinery

Monoubiquitylation of histone H2B (H2Bub1) is catalyzed mainly by the RNF20/RNF40 complex and erased by multiple deubiquitylating enzymes (DUBs). H2Bub1 influences many aspects of chromatin function, including transcription regulation and DNA repair. Cancer cells often display reduced levels of H2Bub1, and this reduction may contribute to cancer progression. The let-7 family of microRNAs comprises multiple members with reported tumor suppressive features, whose expression is frequently downregulated in cancer. We now report that let-7b and let-7c can positively regulate cellular H2Bub1 levels. Overexpression of let-7b and let-7c in a variety of non-transformed and cancer-derived cell lines results in H2Bub1 elevation. The positive effect of let-7b and let-7c on H2Bub1 levels is achieved through targeting of multiple mRNAs, coding for distinct components of the H2B deubiquitylation machinery. Specifically, let-7b and let-7c bind directly and inhibit the mRNAs encoding the DUBs USP42 and USP44, and also the mRNA encoding the adapter protein ATXN7L3, which is part of the DUB module of the SAGA complex. RNF20 knockdown strongly reduces H2Bub1 levels and increases the migration of non-transformed mammary epithelial cells and breast cancer-derived cells. Remarkably, overexpression of let-7b, which partly counteracts the effect of RNF20 knockdown on H2Bub1 levels, also reverses the pro-migratory effect of RNF20 knockdown. Likewise, ATXN7L3 knockdown also increases H2Bub1 levels and reduces cell migration, and this anti-migratory effect is abolished by simultaneous knockdown of RNF20. Together, our findings uncover a novel function of let-7 microRNAs as regulators of H2B ubiquitylation, suggesting an additional mechanism whereby these microRNAs can exert their tumor suppressive effects.

Regulation of actin-binding protein ANLN by antitumor miR-217 inhibits cancer cell aggressiveness in pancreatic ductal adenocarcinoma

Analysis of our microRNA (miRNA) expression signature of pancreatic ductal adenocarcinoma (PDAC) revealed that microRNA-217 (miR-217) was significantly reduced in cancer tissues. The aim of this study was to investigate the antitumor roles of miR-217 in PDAC cells and to identify miR-217-mediated molecular pathways involved in PDAC aggressiveness. The expression levels of miR-217 were significantly reduced in PDAC clinical specimens. Ectopic expression of miR-217 significantly suppressed cancer cell migration and invasion. Transcription of actin-binding protein Anillin (coded by ANLN) was detected by our in silico and gene expression analyses. Moreover, luciferase reporter assays showed that ANLN was a direct target of miR-217 in PDAC cells. Overexpression of ANLN was detected in PDAC clinical specimens by real-time PCR methods and immunohistochemistry. Interestingly, Kaplan-Meier survival curves showed that high expression of ANLN predicted shorter survival in patients with PDAC by TCGA database analysis. Silencing ANLN expression markedly inhibited cancer cell migration and invasion capabilities of PDAC cell lines. We further investigated ANLN-mediated downstream pathways in PDAC cells. "Focal adhesion" and "Regulation of actin binding protein" were identified as ANLN-modulated downstream pathways in PDAC cells. Identification of antitumor miR-217/ANLN-mediated PDAC pathways will provide new insights into the potential mechanisms underlying the aggressive course of PDAC.

miR-217 inhibits triple-negative breast cancer cell growth, migration, and invasion through targeting KLF5

Triple negative breast cancer (TNBC) is one of the most aggressive breast cancers without effective targeted therapies. Numerous studies have implied that KLF5 plays an important roles in TNBC. How is KLF5 regulated by microRNAs has not been well studied. Here, we demonstrated that miR-217 down-regulates the expression of KLF5 and KLF5's downstream target gene FGF-BP and Cyclin D1 in TNBC cell lines HCC1806 and HCC1937. Consequently, miR-217 suppresses TNBC cell growth, migration, and invasion. MiR-217 suppresses TNBC, at least partially, through down-regulating the KLF5 expression. These results suggest that the miR-217-KLF5 axis might serve as a potential target for treatment of TNBC.

miR‑217 inhibits osteogenic differentiation of rat bone marrow‑derived mesenchymal stem cells by binding to Runx2

The elucidation of the underlying molecular mechanisms regulating the osteogenic differentiation of bone marrow‑derived mesenchymal stem cells (BMSCs) is of great importance in improving the treatment of bone‑associated diseases. MicroRNAs (miRNAs) have been proven to regulate the osteogenic differentiation of BMSCs. The present study investigated the role of miR‑217 in the osteogenic differentiation of rat BMSCs. It was observed that miR‑217 expression levels were downregulated during the process of osteogenic differentiation. Subsequently, a dual‑luciferase reporter gene assay demonstrated that miR‑217 targets a putative binding site in the 3'‑untranslated region of the runt related transcription factor 2 (Runx2) gene, which is a key transcription factor for osteogenesis. It was then demonstrated that overexpression of miR‑217 attenuated the osteogenesis of BMSCs and downregulated the expression of Runx2, whereas inhibition of miR‑217 promoted osteoblastic differentiation and upregulated Runx2 expression. Furthermore, the extracellular signal‑regulated kinase (ERK) and p38 mitogen‑activated protein kinase (p38 MAPK) signaling pathways were investigated during osteogenic induction, and the data indicated that miR‑217 may exert a negative effect on the osteogenic differentiation of BMSCs through alteration of ERK and p38 MAPK phosphorylation. The present study therefore concluded that miR‑217 functions as a negative regulator of BMSC osteogenic differentiation via the inhibition of Runx2 expression, and the underlying molecular mechanisms may partially be attributed to mediation by the ERK and p38 MAPK signaling pathways.

MiR-217 promotes cutaneous squamous cell carcinoma progression by targeting PTRF

Increasing evidences have suggested that microRNAs (miRNAs) act a critical role in tumor initiation, progression and metastasis. Deregulated expression of miR-217 has been identified in various tumors. However, the expression and role of miR-217 in the development of cutaneous squamous cell carcinoma (cSCC) remain unclear. In our study, we showed that miR-217 expression was upregulated in the cSCC tissues compared to adjacent non-tumor samples. We also demonstrated that miR-217 expression was upregualted in the cSCCcSCC cell lines. Overexpression of miR-217 promoted cSCCcSCC cell growth, cell cycle and invasion. We identified Polymerase I and Transcript Release Factor (PTRF) as a direct target gene of miR-217 in the SCC13 cell. In addition, PTRF expression was downregulated in the cSCCcSCC tissues. Moreover, we demonstrated that there was a significant inverse correlation between miR-217 and PTRF expression in the cSCCcSCC. Furthermore, overexpression of PTRF could rescue miR-217's oncogenic effect on cSCC. Therefore, these results suggested that upregulation of miR-217 could contribute to development of cSCCcSCC through targeting PTRF.

miR-216b Targets FGFR1 and Confers Sensitivity to Radiotherapy in Pancreatic Ductal Adenocarcinoma Patients Without EGFR or KRAS Mutation

OBJECTIVES

The success of gemcitabine plus radiotherapy is dependent on the mutation status of pancreatic ductal adenocarcinoma (PDAC) tumors in the EGFR and KRAS genes; however, radiotherapy resistance may also be modulated epigenetically by microRNA (miRNA) regulation. In this study, we examined the potential effect of miRNAs on the resistance to radiotherapy in cases without EGFR or KRAS mutation.

METHODS

The association of EGFR and KRAS mutation status and different expression patterns of 6 selected miRNAs related to the EGFR/KRAS signaling pathway were evaluated in the tumors of 42 patients with PDAC.

RESULTS

Reduced miR-216b and miR-217 expression was associated with aggressive tumor characteristics and shortened disease-free survival. In addition, miR-216b expression was reduced 2.7-fold in the cases that did not benefit from therapy, although they did not demonstrate EGFR or KRAS expression (P = 0.0316). A negative correlation between FGFR1 and miR-216b expression (r = -0.355) was found in the tumors of these cases.

CONCLUSIONS

Further studies and validations are required; in the tumors of patients with PDAC without activating mutations and induced expression of EGFR/KRAS genes, down-regulated miR-216b expression may be associated with a poor response to radiotherapy via deregulation of another signaling pathway related to FGFR1 signaling.

miR-218 Inhibits Proliferation, Migration, and EMT of Gastric Cancer Cells by Targeting WASF3

MicroRNAs (miRNAs) play an important role in carcinogenesis. miR-218 is one of the most known miRNAs and has been demonstrated to inhibit progression in gastric cancer. However, the underlying molecular mechanism is not established. In this study, qRT-PCR and Western blot indicated that miR-218 was downregulated in gastric cancer cell lines SGC7901 and BGC823 compared to that in normal gastric epithelial cell line GES-1. MTT and wound scratch assays suggested that overexpression of miR-218 markedly suppressed cell proliferation, migration, and EMT of gastric cancer cells. Furthermore, we proved that WASF3 was a direct target of miR-218 by luciferase reporter assay, and restoration of WASF3 expression impairs miR-218-induced inhibition of proliferation, migration, and EMT in gastric cancer cells SGC7901. In summary, our results demonstrated that miR-218 functions as one of the tumor-suppressive miRNAs and inhibits gastric cancer tumorigenesis by targeting WASF3. miR-218 may serve as a potential therapeutic target for the treatment of gastric cancer.

Long non-coding RNA XIST regulates gastric cancer progression by acting as a molecular sponge of miR-101 to modulate EZH2 expression

BACKGROUND

Long non-coding RNAs (lncRNAs) have emerged as critical regulators of tumor progression. However, the role and molecular mechanism of lncRNA XIST in gastric cancer is still unknown.

METHODS

Real-time PCR analysis was performed to measure the expression levels of lncRNA XIST in gastric cancer tissues and cell lines, the correlation between lncRNA XIST expression and clinicopathological characteristics and prognosis was analyzed in gastric cancer patients. The biological function of lncRNA XIST on gastric cancer cells were determined both in vitro and in vivo. The regulating relationship between lncRNA XIST and miR-101 was investigated in gastric cancer cells.

RESULTS

lncRNA XIST was significantly up-regulated in gastric cancer tissues and cell lines. Overexpression of lncRNA XIST was markedly associated with larger tumor size, lymph node invasion, distant metastasis and TNM stage in gastric cancer patients. Functionally, knockdown of lncRNA XIST exerted tumor-suppressive effects by inhibiting cell proliferation, migration and invasion in vitro and tumor growth and metastasis in vivo. Furthermore, an inverse relationship between lncRNA XIST and miR-101 was found. Polycomb group protein enhancer of zeste homolog 2 (EZH2), a direct target of miR-101, could mediated the biological effects that lncRNA XIST exerted.

CONCLUSIONS

lncRNA XIST is up-regulated and is associated with aggressive tumor phenotypes and patient survival in gastric cancer, and the newly identified lncRNA XIST/miR-101/EZH2 axis could be a potential biomarkers or therapeutic targets for gastric cancer patients.

Potential Diagnostic, Prognostic and Therapeutic Targets of MicroRNAs in Human Gastric Cancer

Human gastric cancer (GC) is characterized by a high incidence and mortality rate, largely because it is normally not identified until a relatively advanced stage owing to a lack of early diagnostic biomarkers. Gastroscopy with biopsy is the routine method for screening, and gastrectomy is the major therapeutic strategy for GC. However, in more than 30% of GC surgical patients, cancer has progressed too far for effective medical resection. Thus, useful biomarkers for early screening or detection of GC are essential for improving patients’ survival rate. MicroRNAs (miRNAs) play an important role in tumorigenesis. They contribute to gastric carcinogenesis by altering the expression of oncogenes and tumor suppressors. Because of their stability in tissues, serum/plasma and other body fluids, miRNAs have been suggested as novel tumor biomarkers with suitable clinical potential. Recently, aberrantly expressed miRNAs have been identified and tested for clinical application in the management of GC. Aberrant miRNA expression profiles determined with miRNA microarrays, quantitative reverse transcription-polymerase chain reaction and next-generation sequencing approaches could be used to establish sample specificity and to identify tumor type. Here, we provide an up-to-date summary of tissue-based GC-associated miRNAs, describing their involvement and that of their downstream targets in tumorigenic and biological processes. We examine correlations among significant clinical parameters and prognostic indicators, and discuss recurrence monitoring and therapeutic options in GC. We also review plasma/serum-based, GC-associated, circulating miRNAs and their clinical applications, focusing especially on early diagnosis. By providing insights into the mechanisms of miRNA-related tumor progression, this review will hopefully aid in the identification of novel potential therapeutic targets.