Stable Dual miR-143 and miR-506 Upregulation Inhibits Proliferation and Cell Cycle Progression

The mainstays of lung cancer pathogenesis are cell cycle progression dysregulation, impaired apoptosis, and unregulated cell proliferation. While individual microRNA (miR) targeting or delivering is a promising approach that has been extensively studied, combination of miR targeting can enhance therapeutic efficacy and overcome limitations present in individual miR regulations. We previously reported on the use of a miR-143 and miR-506 combination via transient transfections against lung cancer. In this study, we evaluated the effect of miR-143 and miR-506 under stable deregulations in A549 lung cancer cells. We used lentiviral transductions to either up- or downregulate the two miRs individually or in combination. The cells were sorted and analyzed for miR deregulation via qPCR. We determined the miR deregulations' effects on the cell cycle, cell proliferation, cancer cell morphology, and cell motility. Compared to the individual miR deregulations, the combined miR upregulation demonstrated a miR-expression-dependent G2 cell cycle arrest and a significant increase in the cell doubling time, whereas the miR-143/506 dual downregulation demonstrated increased cellular motility. Furthermore, the individual miR-143 and miR-506 up- and downregulations exhibited cellular responses lacking an apparent miR-expression-dependent response in the respective analyses. Our work here indicates that, unlike the individual miR upregulations, the combinatorial miR treatment remained advantageous, even under prolonged miR upregulation. Finally, our findings demonstrate potential advantages of miR combinations vs. individual miR treatments.

MiR-506 Promotes Antitumor Immune Response in Pancreatic Cancer by Reprogramming Tumor-Associated Macrophages toward an M1 Phenotype

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer with a poor prognosis, and effective treatments for PDAC are lacking. In this study, we hypothesized that miR-506 promotes antitumor immune response in PDAC by reprogramming tumor-associated macrophages toward an M1 phenotype to reverse its immunosuppressive tumor microenvironment (TME). First, the relationship between TME and the expression of miR-506 was assessed using clinical samples. Our results provided evidence that lower expression of miR-506 was associated with poor prognosis and immunosuppressive TME in PDAC patients. In addition, miR-506 inhibit the PDAC progression and reversed its immunosuppressive microenvironment in a macrophage-dependent manner. Next, we established a PDAC mouse model by orthotopic injection to further explore the role of miR-506 in vivo. Mechanistic investigations demonstrated that miR-506 could reprogram the polarization of M2-like macrophages toward an M1-like phenotype through targeting STAT3. Meanwhile, miR-506 could also sensitize PDAC to anti-PD-1 immunotherapy, because the tumor microenvironment remodeling effects of miR-506 could reprogram macrophage polarization and subsequently promote cytotoxic T lymphocyte (CTL) infiltration. These findings suggest a relationship between miR-506 and TME, especially M2-like macrophages, thus providing novel insights into mechanisms of tumor progression and potential immunotherapeutic targets for further clinical treatment.

MicroRNA-506 as a tumor suppressor in anaplastic thyroid carcinoma by regulation of WNT and NOTCH signaling pathways

Objectives

Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid tumor type that has a poor prognosis due to its high therapeutic resistance. Since ATC accounts for half of thyroid cancer-related deaths, it is required to introduce novel therapeutic targets to increase survival in ATC patients. WNT and NOTCH signaling pathways are the pivotal regulators of cell proliferation and migration that can be regulated by microRNAs. We assessed the role of miR-506 in the regulation of cell migration, apoptosis, and drug resistance via NOTCH and WNT pathways in ATC cells.

Materials and Methods

The levels of miR-506 expressions were assessed in ATC cells and tissues. The levels of NOTCH, WNT, and EMT-related gene expressions were also assessed in miR-506 ectopic expressed cells compared with controls. Cell migration and drug resistance were also evaluated to assess the role of miR-506 in the regulation of ATC aggressiveness.

Results

There were significant miR-506 down-regulations in ATC cells and clinical samples compared with normal cells and margins. MiR-506 suppressed NOTCH and WNT signaling pathways through LEF1, DVL, FZD1, HEY2, HES5, and HEY2 down-regulations, and APC and GSK3b up-regulations. MiR-506 significantly inhibited ATC cell migration and EMT (P=0.028). Moreover, miR-506 significantly increased Cisplatin (P=0.004), Paclitaxel (P<0.0001), and Doxorubicin (P=0.0014) sensitivities in ATC cells.

Conclusion

MiR-506 regulated EMT, cell migration, and chemoresistance through regulation of WNT and NOTCH signaling pathways in ATC cells. Therefore, after confirmation with animal studies, it can be introduced as an efficient novel therapeutic factor for ATC tumors.

MiR-506 targets polypyrimidine tract-binding protein 1 to inhibit airway inflammatory response and remodeling via mediating Wnt/β-catenin signaling pathway

BACKGROUND

Airway remodeling, which contributes to the clinical course of childhood asthma, occurs due to airway inflammation and is featured by anomalous biological behaviors of airway smooth muscle cells (ASMCs). microRNA (miRNA) plays an essential role in the etiopathogenesis of asthma.

OBJECTIVE

This research was aimed to characterize miR-506 in asthma and uncover potential regulatory machinery.

MATERIAL AND METHODS

The asthmatic cell model was established by treating ASMCs with transforming growth factor-beta1 (TGF-β1) and assessed by the levels of interleukin (IL)-1β and interferon gamma (IFN-γ). Using real-time quantitative polymerase chain reaction, mRNA expression of miR-506 and polypyrimidine tract-binding protein 1 (PTBP1) was measured. Cell counting kit-8 and Transwell migration tests were used for estimating the capacity of ASMCs to proliferate and migrate. Luciferase reporter assay was used to corroborate whether miR-506 was directly bound to PTBP1. Expression of PTBP1, collagen I and III, and essential proteins of the wingless-related integration (Wnt)/β-catenin pathway (β-catenin, c-MYC and cyclin D1) was accomplished by Western blot analysis. The involvement of Wnt/β-catenin signaling in asthma was confirmed by Wnt signaling pathway inhibitor (IWR-1).

RESULTS

miR-506 was poorly expressed in asthmatic tissues and cell model. Functionally, overexpression of miR-506 reduced aberrant proliferation, migration, inflammation and collagen deposition of ASMCs triggered by TGF-β1. Mechanically, miR-506 directly targeted the 3' untranslated region (3-UTR) of PTBP1 and had a negative regulation on PTBP1 expression. Moreover, overexpression of miR-506 suppressed the induction of Wnt/β-catenin pathway. The administration of IWR-1 further validated negative correlation between miR-506 and the Wnt/β-catenin pathway in asthma.

CONCLUSION

Our data indicated that targeting miR-506/PTBP1/Wnt/β-catenin axis might point in a helpful direction for treating asthma in children.

The novel circular RNA HIPK3 accelerates the proliferation and invasion of hepatocellular carcinoma cells by sponging the micro RNA-124 or micro RNA-506/pyruvate dehydrogenase kinase 2 axis

Circular RNAs (circRNAs) have been confirmed to be associated with the progression of various cancers, including hepatocellular carcinoma (HCC). However, the role and mechanism of circHIPK3 in HCC are still unclear. To investigate its function, circHIPK3 expression was first determined by RT–qPCR in HCC tissues or cells. Functionally, cell proliferation and invasion were investigated by CCK-8, EdU, or Transwell assays. In terms of understanding the mechanism, the interaction of the circRNA HIPK3/micro RNA 124 (miRNA 124) or micro RNA 506 (miRNA506) /PDK2 regulatory loop was verified by dual-luciferase reporter gene assay. In addition, a xenograft tumor model was established to confirm the impact of circHIPK3 on the growth of HCC cells in vivo. We found that circHIPK3 was upregulated in HCC patients and associated with clinical characteristics, while miR-124 and miR-506 were downregulated in HCC patients. Additionally, we proved that knock down of circHIPK3 remarkably suppressed the proliferation and invasion of HCC cells. Mechanistically, circHIPK3 directly bound to miR-124 or miR-506 and inhibited their expression, and PDK2 was a target gene of miR-124 or miR-506. Moreover, circHIPK3 overexpression reversed the inhibitory effect of miR-124 or miR-506 on HCC progression. miR-124 or miR-506 could also suppress tumorigenesis of HCC cells by PDK2. Furthermore, in vivo evidence confirmed that knock down of circHIPK3 inhibited tumor formation. We suggest that circHIPK3 can accelerate the proliferation and invasion of HCC cells by sponging miR-124 or miR-506 to upregulate PDK2, which is the underlying mechanism of circHIPK3-induced HCC progression.

Value of serum miR-922 and miR-506 expression levels in the diagnosis and prognostic assessment of childhood acute lymphoblastic leukemia

OBJECTIVES

To study the value of serum miR-922 and miR-506 expression levels in the diagnosis and prognostic assessment of childhood acute lymphoblastic leukemia (ALL).

METHODS

A total of 132 children with ALL (ALL group) and 80 healthy children (healthy control group) were prospectively selected in this study. Quantitative real-time polymerase chain reaction was used to measure the expression levels of serum miR-922 and miR-506 in both groups. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic value of miR-922 and miR-506 for childhood ALL. The Kaplan-Meier method was used to plot survival curves, and multivariate COX regression models were used to analyze the risk factors for poor prognosis in children with ALL.

RESULTS

The ALL group had significantly higher expression levels of serum miR-922 and miR-506 than the control group (P<0.001). The ROC curve analysis showed that the optimal cut-off values of miR-922 and miR-506 for the diagnosis of childhood ALL were 1.46 and 2.17, respectively. The high miR-922 expression (≥1.46) group and high miR-506 expression (≥2.17) group had significantly higher incidence rates of lymph node enlargement, leukocyte count ≥50×10⁹/L, medium-high risk stratification, mixed-lineage leukemia (MLL) gene rearrangement, and karyotype abnormality than the low miR-922 expression group and low miR-506 expression group (P<0.05). The Kaplan-Meier analysis showed that high expression of miR-922 and miR-506 was associated with short survival time in children with ALL (P<0.05). The multivariate COX regression analysis showed that leukocyte count ≥50×10⁹/L, medium-high risk stratification, MLL gene rearrangement, miR-922≥1.46, and miR-506≥2.17 could indicate poor prognosis in children with ALL (P<0.05).

CONCLUSIONS

The expression levels of miR-922 and miR-506 are of good value in the diagnosis and prognostic assessment of childhood ALL.

miR-506 in patients with chronic myeloid leukemia and its effect on apoptosis of K562 cells

OBJECTIVE

To explore the expression of miR-506 in chronic myeloid leukemia (CML) and its influence on the biological function of CML cells.

METHODS

Altogether 84 CML patients from February 2012 to September 2014 were obtained as the observation group (OG), and 71 healthy people were taken as the control group (CG). miR-506 was tested using RT-qPCR, and the 5-year survival of patients with high and low expression of miR-506 was compared with the median value of miR-506 as the limit. ROC curve was applied to detect the value of miR-506 in diagnosing CML and predicting the 5-year survival of patients, and K562 cell line was transfected with miR-506 inhibitor and miR-506 mimic for observing its effects on the cell proliferation and apoptosis.

RESULTS

miR-506 in CML patients was evidently lower than that in healthy people, the AUC of diagnosis of miR-506 was 0.883, the total survival of patients with low miR-506 was evidently lower than those with high miR-506, and the AUC of predicted survival of patients was 0.778. The proliferation of cells transfected with miR-506 inhibitor was promoted, the apoptosis and the survival rate reduced.

CONCLUSION

miR-506 is evidently reduced in CML, and may be applied as a diagnostic and predictive treatment for CML and 5-year related survival; it can also can hinder the viability of K562 cells and promote apoptosis.

Prognostic and Diagnostic Values of miR-506 and SPON 1 in Colorectal Cancer with Clinicopathological Considerations

PURPOSE

One of the most common cancers in the world is colorectal cancer, which has increased significantly in recent decades. In the carcinogenicity process in the colon, there are genes involved in various cellular processes, such as cell cycle, apoptosis, and cell migration. According to studies carried out, both miR-506 and SPON 1 genes are involved in the process which initiates and promotes cancer. In this study, alterations in the expression of target genes from the viewpoint of carcinogenicity were studied and evaluated.

METHODS

Fifty tumor tissues and normal marginal tissue were collected from patients who were undergoing colorectal cancer surgery. After the extraction of RNA, the real-time PCR method was performed to evaluate the gene expression. Also, alterations of gene expression in response to defined amounts of chemotherapeutic drugs (IC50) were evaluated. P < 0.05 was considered statistically significant.

RESULTS

The relative expression level of miR-506 in tumor tissues was significantly decreased in comparison with healthy marginal tissues (P = 0.044). On the other hand, the SPON1 gene expression level was decreased too in tumor tissues in comparison with healthy marginal tissues (P = 0.019). There was also a significant relationship between the expression of target genes and clinicopathological involvement. However, there was no significant alteration in these genes along with the chemotherapeutic drug.

CONCLUSION

These findings suggest that the relative expression of miR-506 and SPON 1 gene can be considered as a diagnostic or predictive biomarker for colorectal cancer. However, further studies on protein levels should be conducted.

Alginic acid inhibits non-small cell lung cancer-induced angiogenesis via activating miR-506 expression

Angiogenesis is a key event in non-small cell lung cancer progression. Alginic acid (AA), a kind of naturally occurring polyuronic acid, is generally enriched in edible brown algae. Recent studies have uncovered its anti-anaphylactic and anti-inflammatory properties. However, the effects of AA on human malignancies remain unknown. Herein, efficient inhibition of AA on NSCLC-induced angiogenesis was observed with tube formation and xenograft models. Subsequent results indicated that AA downregulated the expression of VEGF-A, a key angiogenesis-inducing cytokine. In addition, AA downregulated STAT3, a transcriptional inducer of VEGF-A and increased non-coding RNA miR-506 expression, respectively. Furthermore, miR-506 directly modulated STAT3 relying on base pairing the 3'-UTR in STAT3 mRNA. We also found that abrogation of miR-506 abolished the inhibitory effect of AA on VEGF-A expression and NSCLC-induced angiogenesis. Finally, xenografts experiments also showed that oral administration of AA could significantly attenuate NSCLC angiogenesis, indicated by decreased micro-vessel density (MVD) and the MVD marker CD31 expression in xenografts tissues. Correspondingly, AA treatment also downregulated VEGF-A, STAT3 and increased miR-506 expression in xenografts samples, respectively. Taken together, these results suggested that AA could suppress NSCLC-induced angiogenesis via miR-506/STAT3/VEGF-A axis. .

miR-506-loaded gelatin nanospheres target PENK and inactivate the ERK/Fos signaling pathway to suppress triple-negative breast cancer aggressiveness

Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer. Some microRNAs (miRNAs) were abnormally expressed in TNBC, and they are closely related to the occurrence and progression of TNBC. Here, we found that miR-506 was significantly downregulated in TNBC and relatively lower miR-506 expression predicted a poorer prognosis. Moreover, we found that miR-506 could inhibit MDA-MB-231 cell viability, colony formation, migration, and invasion, and suppress the ERK/Fos oncogenic signaling pathway through upregulating its direct target protein proenkephalin (PENK). Therefore, miR-506 was proposed as a nucleic acid drug for TNBC therapy. However, miRNA is unstable in vivo, which limiting its application as a therapeutic drug via conventional oral or injected therapies. Here, a gelatin nanosphere (GN) delivery system was applied for the first time to load exogenous miRNA. Exogenous miR-506 mimic was loaded on GNs and injected into the in situ TNBC animal model, and the miR-506 could achieve sustained and controlled release. The results confirmed that overexpression of miR-506 and PENK in vivo through loading on GNs inhibited in situ triple-negative breast tumor growth and metastasis significantly in the xenograft model. Moreover, we indicated that the ERK/Fos signaling pathway was intensively inactivated after overexpression of miR-506 and PENK both in vitro and in vivo, which was further validated by the ERK1/2-specific inhibitor SCH772984. In conclusion, this study demonstrates that miR-506-loaded GNs have great potential in anti-TNBC aggressiveness therapy.

MiR-506 exerts antineoplastic effects on osteosarcoma cells via inhibition of the Skp2 oncoprotein

S-phase kinase-associated protein 2 (Skp2) performs oncogenic functions in cancers; however, how Skp2 is regulated post-transcriptionally is elusive in osteosarcoma. Therefore, we determined whether miR-506 could directly target Skp2 in osteosarcoma to perform its tumor suppressive functions. Here, we found that miR-506 mimics suppressed cell viability, induced apoptosis, and attenuated migration and invasion in osteosarcoma cells. Moreover, upregulation of Skp2 accelerated cell viability and motility and rescued the tumor suppressive effect of miR-506 in osteosarcoma cells. Moreover, downregulation of Skp2 inhibited cell viability and decreased cell motility, which enhanced the antitumor activity induced by miR-506 mimic transfection in osteosarcoma cells. Our western blotting results implied that miR-506 inhibited Skp2 expression and subsequently upregulated Foxo1 and p57 in OS cells. In summary, miR-506 performs an anticancer activity via directly targeting Skp2 in osteosarcoma cells, indicating that inactivation of Skp2 by miR-506 might be an alternative strategy for treating osteosarcoma.

Overexpression of MiR-506 in Jurkat (Acute T Cell Leukemia) Cell Line

Background & Objective:

Acute lymphoblastic leukemia (ALL) is a malignant disease that arises from various mutations in B or T-lymphoid progenitors. MicroRNAs (miRNAs) regulate gene expression by binding to the 3' untranslated region of protein-coding genes. Dysregulation of miRNA expression may result in the development of cancerous phenotypes. Therefore, for the first time in this field, the present study aims to investigate the effect of overexpression of miR-506 in Jurkat (acute T cell leukemia) cell line.

Methods:

In this study, Jurkat cell lines were cultured in RPMI-1640 medium. Next, miR-506 was transfected with concentrations of 50 and 100 nM with Lipofectamine 2000. The accuracy of the transfection was confirmed by the transfection of siRNA conjugated with FITC. 48 h after transfection, the cells were prepared for other tests (flow cytometry, MTT assay, and RNA extraction). The expression level of miR-506 in the cells was analyzed using the quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Finally, SPSS 21 software was used for the data analysis.

Results:

According to our results, the viability of cells in concentrations of 50 and 100 nM was significantly higher than the control group. By overexpression of miR-506, the expressions of pro-apoptotic genes (p53, p21) and anti-apoptotic gene B-cell lymphoma-2 (BCL-2) are decreased and increased, respectively.

Conclusion:

This study showed that miR-506 may function as an oncogenic miRNA in the T- ALL cell line. In conclusion, overexpression of miR-506 leads to an increase in viable cancer cells.

Linc00473 potentiates cholangiocarcinoma progression by modulation of DDX5 expression via miR-506 regulation

Background

Cholangiocarcinoma (CCA) is a mortal cancer with high mortality, whereas the function and mechanism of occurrence and progression of CCA are still mysterious. Long non-coding RNAs (lncRNAs) could function as important regulators in carcinogenesis and cancer progression. Growing evidences have indicated that the novel lncRNA linc00473 plays an important role in cancer progression and metastasis. However, its function and molecular mechanism in CCA remain unknown.

Methods

The linc00473 expression in CCA tissues and cell lines was analyzed using qRT-PCR. Gain- and loss-of-function experiments were conducted to investigate the biological functions of linc00473 both in vitro and in vivo. Insights into the underlying mechanisms of competitive endogenous RNAs (ceRNAs) were determined by bioinformatics analysis, dual-luciferase reporter assays, qRT-PCR arrays, RNA immunoprecipitation (RIP) and rescue experiments.

Results

Linc00473 was highly expressed in CCA tissues and cell lines. Linc00473 knockdown inhibited CCA growth and metastasis. Furthermore, linc00473 acted as miR-506 sponge and regulated its target gene DDX5 expression. Rescue assays verified that linc00473 modulated the tumorigenesis of CCA by regulating miR-506.

Conclusions

The data indicated that linc00473 played an oncogenic role in CCA growth and metastasis, and could serve as a novel molecular target for treating CCA.

Reactivation of microRNA-506 inhibits gastric carcinoma cell metastasis through ZEB2

MicroRNAs (miRNAs) are frequently dysregulated in a variety of human cancers, including gastric carcinoma. To improve our understanding of the role of miRNAs in gastric carcinoma and potential identify novel biomarkers or therapeutic agents, we performed microarray analysis to identify differentially expressed miRNAs in gastric carcinoma, compared with paired non-cancerous gastric tissues. We identified significantly differentially expressed miRNAs in gastric carcinoma tissues, including miR-506. We validated the microarray results by quantitative reverse transcription polymerase chain reaction in 26 specimens and confirmed significant downregulation of miR-506 in gastric carcinoma. Bioinformatics analysis predicted ZEB2 (zinc finger E-box-binding homeobox 2) as a potential target of miR-506. MiR-506 levels and ZEB2 levels were inversely correlated in gastric carcinoma, and low miR-506 levels in gastric carcinoma were associated with poor prognosis. Overexpression of miR-506 in gastric carcinoma cells significantly inhibited cell migration and invasion, while depletion of miR-506 in gastric carcinoma cells significantly increased cell migration and invasion. Transplantation of miR-506-overexpressing gastric carcinoma cells developed significantly smaller tumor, compared to the control. Thus, our results suggest that miR-506 may function as a tumor suppressor and targets and inhibits ZEB2 in gastric carcinoma.

lncRNA NEAT1 regulates fibrosis and inflammatory response induced by nonalcoholic fatty liver by regulating miR-506/GLI3

As one of the most common liver disorders worldwide, nonalcoholic fatty liver disease (NAFLD) begins with the abnormal accumulation of triglyceride (TG) in the liver and can lead to inflammation and fibrosis. Long noncoding RNA (lncRNA) NEAT1 was reported to promote NAFLD progress. However, its molecular mechanism in NAFLD was not fully clear. In vitro cellular model of NAFLD was established with BRL3A cell treated by free fatty acid (FFA). Cell Counting Kit-8 (CCK-8) assay was carried out to assess cell proliferation. The expression of mRNA and protein of inflammation and fibrosis in BRL3A cell was detected by qRT-PCR and Western blot. Bioinformatics and dual-luciferase reporter assays were used to predict and validate the interaction between NEAT1 and miR-506 as well as GLI3 and miR-506. NEAT1 was upregulated while miR-506 was downregulated in the progression of NAFLD. Meanwhile, NEAT1 and miR-506 were proved to regulate fibrosis, inflammatory response, and lipid metabolism. Knockdown of NEAT1 inhibited GLI3 expression and promoted miR-506 expression, Overexpression of miR-506 inhibited NEAT1 and GLI3 expression. Moreover, dual-luciferase reporter assays proved that miR-506 could bind to NEAT1 and GLI3, whereas NEAT1 could sponge miR-506 to regulate GLI3 expression. lncRNA NEAT1 could regulate fibrosis, inflammatory response, and lipid metabolism via the miR-506/GLI3 axis as a ceRNA, which is a novel mechanistic role in the regulation of NAFLD. These results provide a new potential treatment target for NAFLD.

Aberrant Expression of miR-103, miR-184, miR-378, miR-497 and miR-506 in Tumor Tissue from Patients with Oral Squamous Cell Carcinoma Regulates the Clinical Picture of the Patients

BACKGROUND

This study aimed to evaluate the expression patterns of miR-103, miR-184, miR-378, miR497 and in squamous cell carcinoma (SCC) of the tongue and to be compared with normal peripheral tissues.

METHODS

Tumor and marginal tissues were obtained from 50 patients with OSCC. After RNA extraction, expression level of miR-103, miR-184, miR-378, miR497, and miR506 was estimated using SYBR green master mix and real-time quantitative PCR.

RESULTS

It was observed that, there was no detectable difference in expression level of miR-103 between tumoral and marginal tissues. However, expression level of miR-184, and miR-378 showed significant increase in tumor tissue samples compared to marginal tissue samples. MiR-497 and miR-506 demonstrated considerable decrease in tumoral cells in comparison with peripheral tissues. Moreover, the expression level of miRNAs was associated with clinicopathological features of the patients.

CONCLUSIONS

Our data indicated that miR-184, miR-378, miR-497, and miR-506 can be used as a potential diagnostic and prognostic biomarker in OSCC. Nevertheless, more studies are needed to confirm this claim.
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LINC00963 Confers Oncogenic Properties in Glioma by Regulating the miR-506/BCAT1 Axis

Background

Glioma is a prevalent disease of the central nervous system with a high incidence and mortality rate. Many long noncoding RNAs (lncRNAs) have been determined to be critical regulators of glioma oncogenesis. However, the function and mechanism of LINC00963 in glioma have not been fully elucidated.

Methods

The expression level of RNA was determined by qRT-PCR, and the protein level was determined by Western blot analysis. A luciferase activity assay was conducted to verify the interaction between miRNA and lncRNA or the target gene. The proliferation, cell cycle distribution, invasion, and migration were evaluated by MTT, EdU, flow cytometry, wound-healing and Transwell invasion assays, respectively. In vivo tumor growth was evaluated in a xenograft nude mouse model.

Results

We found that LINC00963 was upregulated in glioma cells and tissues and associated with the poor prognosis of patients with glioma. Ectopic expression of LINC00963 promoted cell proliferation, cell cycle progression, migration, and invasion in vitro and tumorigenesis in vivo. Mechanistically, the results of luciferase activity and RNA pulldown assays validated that LINC00963 could act as a molecular sponge of miR-506. Reciprocal repression was found between LINC00963 and miR-506. In addition, BCAT1 was identified as a target of miR-506, and both the mRNA and protein levels of BCAT1 were reduced by miR-506. In tumor tissues, the expression of BCAT1 was negatively and positively correlated with miR-506 and LINC00963 expression, respectively. The reintroduction of BCAT1 in glioma cells abolished the tumor suppressive function of miR-506 by promoting cell viability and motility. The upregulated LINC00963 and BCAT1 were associated with the aggressive phenotypes of tumors.

Conclusion

Our data revealed that LINC00963 confers oncogenic function in the progression of glioma and that the LINC00963/miR-506/BCAT1 axis may be a novel mechanism and therapeutic strategy for this disease.

circPCNX and Pecanex Promote Hepatocellular Carcinoma Cell Viability by Inhibiting miR-506

Introduction

Hepatocellular carcinoma (HCC) is one of the most common malignant cancers, while the molecular mechanism is not clear. Circular RNAs (circRNAs) are a class of naturally occurring endogenous noncoding RNAs that prove to play important roles in the occurrence, development and prognosis of HCC. In this study, we focused on an abnormally expressed circular RNA-circPCNX in HCC and study the function of circPCNX and Pecanex (PCNX) in HCC.

Methods

Circular RNA sequencing was used to find the abnormally expressed circRNAs and qRT-PCR was used to verify it. CCK8 assay, colony formation assay and cell apoptosis assay were used to study biological functions, and Luciferase reporter assay and Western blot analysis were used to study the mechanism.

Results

We observed that circPCNX and Pecanex were significantly upregulated in tumor tissues of patients with HCC and correlated with clinicopathological variables or prognosis of HCC patients. Functional investigations showed circPCNX and Pecanex could promote the viability of HCC cells. Mechanistic investigations suggested that both circPCNX and Pecanex 3'UTR could bind to miR-506 and subsequently inhibited the miR-506-induced anticarcinogenic effect in HCC.

Conclusion

Our study revealed the function of circPCNX and Pecanex in promoting HCC progression and acting as biomarkers in the clinical estimate and treatment of HCC.

MiR-506 Targets UHRF1 to Inhibit Colorectal Cancer Proliferation and Invasion via the KISS1/PI3K/NF-κB Signaling Axis

Background

The UHRF1 gene is an epigenetic modification factor that mediates tumor suppressor gene silencing in a variety of cancers. Related studies have reported that UHRF1 can inhibit the expression of the KISS1 gene. However, the regulatory mechanism underlying UHRF1 expression in colorectal cancer (CRC) is still unclear. The aim of this study was to gain a better understanding of the regulation of UHRF1 expression in CRC and to determine whether it regulates the mechanism by which KISS1 promotes CRC metastasis.

Methods

In the present study, the levels of miR-506, UHRF1 and KISS1 expression in CRC tissues and in human CRC cell lines were studied using quantitative real-time PCR (qRT-PCR) and Western blotting. Cell proliferation, migration, and invasion assays are used to detect cell proliferation, migration, and invasion. A dual-luciferase reporter system was used to confirm the target gene of miR-506.

Results

This study found that UHRF1 protein is highly expressed in CRC tissues and negatively correlated with KISS1 protein expression. UHRF1 overexpression activates the PI3K/NF-κB signaling pathway by inhibiting the mRNA expression levels of pathway mediators. Bioinformatics analysis and luciferase reporter gene assays confirmed that miR-506 targets UHRF1.

Conclusion

This study identified the regulation of UHRF1 expression in CRC and the mechanism of CRC metastasis. UHRF1 may be a new potential target molecule for future CRC metastasis treatment.

MicroRNA‑506 regulates apoptosis in retinoblastoma cells by targeting sirtuin 1

BACKGROUND

MicroRNAs have been reported to participate in the initiation and progression of retinoblastoma (RB), most common malignancy in children. The refractory mechanisms of chemoresistance and the toxicity of chemotherapies hindered the treatment especially on young children. Novel RB therapies are urgently required. MiR-506 is probed to be associated with the tumorigenesis of various cancers whilst the role of this miR in RB remains unclear.

METHODS

Here, the impact of miR-506 on RB cell survival in vitro and tumorigenesis in vivo was examined. MiR-506 expression was examined in human RB samples and cell lines as compared with healthy tissues and non-RB cells. EdU staining and colony formation assay were performed to determine the effect of miR-506 on RB cell growth. TdT-mediated dUTP nick end labeling (TUNEL) staining and flow cytometry analysis were applied to detect the apoptotic cell number after miR-506 was downregulated in RB cells. Furthermore, dual-luciferase reporter assay was utilized to confirm the direct interaction between miR-506 and SIRT1 gene.

RESULTS

MiR-506 expression was upregulated in 20 human RB samples from patients as well as in human RB cell lines, WERI-Rb1 and Y79, as compared to that in healthy tissues and non-RB cells. In contrast, the expression of sirtuin 1 (SIRT1), known as NAD-dependent deacetylase, was downregulated in RB samples and cell lines. Aberrant reduced miR-506 expression impaired survival and proliferation of WERI-Rb1 and Y79 cells. The depletion of miR-506 expression promoted apoptosis of the two RB cell lines. The results of bioinformatics analysis and dual-luciferase assay exhibited that miR-506 targeted the 3'-untranslated region of SIRT1 on silencing purpose. The SIRT1 silencing lessened the miR-506 inhibition on RB cell proliferation and undermined apoptosis.

CONCLUSION

The results provided an insight into the role of miR-506 during RB development and offered potential pharmaceutical strategy for RB diagnosis.

MicroRNA-506 upregulation contributes to sirtuin 1 inhibition of osteoclastogenesis in bone marrow stromal cells induced by TNF-α treatment

As a deacetylase relying on NAD, sirtuin 1 (SIRT1) has been proven to inhibit osteoclastogenesis directly by repressing reactive oxygen species (ROS) production and TRPV1 channel stimulation modulated by TNF-α. MicroRNAs do not have coding functions, but they influence the expression of particular genes after transcription. Nevertheless, the current understanding of the impact of SIRT1 on osteoclastogenesis is insufficient. Our research explored whether and how miRNAs contributed to osteoclast differentiation modulated by SIRT1 in vitro. In osteoclastogenesis induced by RANKL in bone marrow-derived macrophages (BMMs), repression of SIRT1 expression and enhancement of miR-506 expression were discovered. Transfection with an miR-506 inhibitor repressed miR-506 concentration in BMMs treated with RANKL. Additional research revealed that BMMs with repressed miR-506 treated with RANKL displayed phenotypes with suppressed osteoclastogenesis, as demonstrated by TRAP staining, reduced function, decreased expression of osteoclast markers and correlated genes, and reduced multinuclear cell quantity. Bioinformatics prediction outcomes and the dual-luciferase reporter test suggested that miR-506 targeted the SIRT1 3'-UTR for silencing. Decreased miR-506 in BMMs induced by RANKL caused SIRT1 upregulation. Additionally, treatment with EX-527 (SIRT1 repressor) or SIRT1 silencing attenuated repression caused by miR-506 depletion in BMMs treated with RANKL. Furthermore, TNF-α was repressed via miR-506 inhibition but was enhanced following EX-527 incubation as well as SIRT1 depletion. TRPV1 channel stimulation and ROS generation, which was related to osteoclastogenesis, were reduced via miR-506 depletion. miR-506 modulated osteoclastogenesis by targeting SIRT1 expression in part through modulation of the TRPV1 channel, ROS production, and TNF-α.

MiRNA-506 inhibits rheumatoid arthritis fibroblast-like synoviocytes proliferation and induces apoptosis by targetting TLR4

Fibroblast-like synoviocytes (FLSs) play a crucial role in rheumatoid arthritis (RA) pathogenesis. While miRNA (miR)-506 has been implicated in the progression of multiple diseases, its role in RA remains to be explored. The present study evaluated the function of miR-506 in the regulation of RA-FLSs. FLSs were prepared from RA and healthy synovial tissues. The expression of miR-506 was measured by quantitative real time PCR (qRT-PCR). The effects of miR-506 on RA-FLSs proliferation and apoptosis were detected by cell counting Kit-8 and flow cytometry assays, respectively. The determination of TNF-α, IL-6, and IL-1β concentrations in RA-FLSs supernatant were done by ELISA. The levels of miR-506 were detected to be significantly lower in the synovial tissues and FLSs of RA than in the synovial tissues and FLSs of healthy controls. The miR-506 up-regulation in RA-FLSs significantly inhibited the proliferation and promoted cell cycle arrest at the G₀/G₁ phase. The overexpression of miR-506 induced apoptosis, along with an increase in activities of caspase-3 and -8. A target gene Toll-like receptor 4 (TLR4) under the direct regulation of miR-506 was identified through the luciferase assay, qRT-PCR and western blot analysis. Forced overexpression of TLR4 in the rescue experiments showed that TLR4 effectively reversed the effect on proliferation and apoptosis in miR-506-overexpressing RA-FLSs. Thus, miR-506 may be a potential target for RA prevention and therapy of RA.

miR-506 regulates cell proliferation and apoptosis by affecting RhoA/ROCK signaling pathway in hepatocellular carcinoma cells

BACKGROUND

Hepatocellular carcinoma (HCC), is the third leading cause of cancer-related death. MicroRNA-506 (miR-506) has been reported to exhibit abnormal expression in HCC; however, the role of miR-506 in HCC and the molecular mechanisms underlying miR-506 in HCC remain unclarified.

METHODS

Quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay was performed to detect the expression of miR-506 and Rho associated coiled-coil containing protein kinase 2 (ROCK2). Cell proliferation and apoptosis were evaluated by MTT assay and flow cytometry, respectively. Bioinformatics analysis and luciferase reporter assays were performed to identify the regulation between miR-506 and ROCK2. Western blot assay was performed to detect the expression of ROCK2, RhoA, and Ras-related C3 botulinum toxin substrate 1 (Rac1). The tumor growth in vivo was evaluated in a HCC xenograft mice model.

RESULTS

The mRNA levels of ROCK2 were significantly upregulated, while miR-506 levels were significantly downregulated in HCC tissues and cells. The expression of ROCK2 was negatively correlated with miR-506 in HCC tissues. In vitro, upregulation of miR-506 inhibited proliferation and induced apoptosis, and downregulation of miR-506 promoted proliferation and blocked apoptosis in HepG2 and Hep3B cells. ROCK2 was a target gene of miR-506 and miR-506 regulated the expression of ROCK2 in HepG2 and Hep3B cells. Furthermore, downregulation of miR-506 partially attenuated the tumor-suppressive effect of ROCK2 knockout on HepG2 and Hep3B cells, and upregulation of miR-506 partially attenuated the oncogenic effect of ROCK2 overexpression on HepG2 and Hep3B cells; Overexpression of ROCK2 increased and ROCK2 knockdown decreased the expression of Rac1, which were attenuated by upregulation of miR-506 or downregulation of miR-506, respectively. In addition, ROCK2 overexpression or knockdown hadno significant effect on RhoA expression. In vivo, upregulation of miR-506 suppressed tumor growth, while downregulation of miR-506 promoted tumor growth.

CONCLUSION

miR-506 was involved in cell proliferation and apoptosis by affecting RhoA/ROCK signaling pathway in HCC cells. Our results provide a novel mechanism of miR-506-mediated suppressive effects on HCC tumorigenesis.

miR-506 is a YAP1-dependent tumor suppressor in laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) accounts for 95% of laryngeal cancer incidence. Tobacco use has been shown to have a linear association with the development of the disease. While early diagnosis and treatment of LSCC are critical in improving the 5-year survival rate and quality of life, diagnosis of early-stage LSCC remains challenging because of the unapparent symptoms. Here, we report that miR-506, a critical regulator in many types of cancers, is aberrantly suppressed in LSCC patient tissues and cultured cancer cells. This is likely responsible for the enhanced production of YAP1 protein, a transcriptional factor that is well known for its oncogenic roles in LSCC malignancy. Statistical analysis has confirmed that the expression levels of miR-506 and YAP1 are strongly correlated with the malignant statuses of patient tumors. Restoring the expression level of miR-506 in cultured LSCC cells significantly inhibited proliferation, migration and invasion of the cells. The miR-506 and YAP1 regulatory network seems to affect at least pathways involved in apoptosis. Our study, for the first time, has demonstrated a tumor suppressive role of miR-506 in LSCC. This opens new opportunities for further exploring the molecular details of the development of the disease and thus will facilitate the development of novel diagnosis and therapeutic strategies.

Long noncoding RNA NEAT1-modulated miR-506 regulates gastric cancer development through targeting STAT3

Accumulating evidence has indicated that long noncoding RNA NEAT1 exerts critical roles in cancers. So far, the detailed biological role and mechanisms of NEAT1, which are responsible for human gastric cancer (GC), are still largely unknown. Here, we observed that NEAT1 and STAT3 expressions were significantly upregulated in human GC cells including BGC823, SGC-7901, AGS, MGC803, and MKN28 cells compared with normal gastric epithelial cells GES-1, while miR-506 was downregulated. We inhibited NEAT1 and observed that NEAT1 inhibition was able to repress the growth, migration, and invasion of GC cells. Conversely, overexpression of NEAT1 exhibited an increased ability of GC progression in BGC823 and SGC-7901 cells. Bioinformatics analysis, dual luciferase reporter assays, RIP assays, and RNA pull-down tests validated the negative binding correlation between NEAT1 and miR-506. In addition, it was found that miR-506 can modulate the expression of NEAT1 in vitro. STAT3 was predicted as a messenger RNA (mRNA) target of miR-506, and miR-506 mimics can suppress STAT3 mRNA expression. Subsequently, it was observed that downregulation of NEAT1 can restrain GC development by decreasing STAT3, which can be reversed by miR-506 inhibitors. Therefore, it was hypothesized in our study that NEAT1 can be recognized as a competing endogenous RNA to modulate STAT3 by sponging miR-506 in GC. In conclusion, we implied that NEAT1 can serve as an important biomarker in GC diagnosis and treatment.

MiR-506 Promotes Natural Killer Cell Cytotoxicity against Human Hepatocellular Carcinoma Cells by Targeting STAT3

PURPOSE

It is well documented that natural killer (NK) cytotoxicity against hepatocellular carcinoma (HCC) cells is impaired in HCC, which might account for the failure of anti-tumor immune response. miRNAs are considered as important regulators for the development and functions of NK cells. However, the entire role of miR-506 in NK cells remains far from being addressed.

MATERIALS AND METHODS

The expressions of miR-506 and signal transducer and activator of transcription 3 (STAT3) mRNA in primary NK cells from HCC patients and healthy controls were detected by quantitative real-time PCR. NK cell cytotoxicity was assessed by CFSE/7AAD cytotoxicity assay and lactate dehydrogenase assay. Luciferase reporter assay, RNA immunoprecipitation assay, and western blot were conducted to confirm the interaction between miR-506 and STAT3.

RESULTS

miR-506 expression was downregulated and STAT3 mRNA was upregulated in primary NK cells from HCC patients. Primary NK cells from HCC patients showed remarkably reduced cytotoxicity against SMMC7721 or HepG2 cells. NK cell cytotoxicity was positively correlated with miR-506 expression and negatively correlated with STAT3 mRNA expression. Additionally, miR-506 overexpression enhanced NK cell cytotoxicity against HCC cells, while miR-506 inhibitor showed the reverse effect. Moreover, miR-506 could suppress STAT3 expression by directly targeting 3'-untranslated regions of STAT3. A negative correlation between miR-506 and STAT3 mRNA expression in HCC patients was observed. Mechanistically, overexpressing STAT3 greatly reversed miR-506-mediated promotion of NK cell cytotoxicity against HCC cells.

CONCLUSION

miR-506 enhanced NK cell cytotoxicity against HCC cells by targeting STAT3, suggesting that modulating miR-506 expression maybe a promising approach for enhancing NK cell-based antitumor therapies.

Primary biliary cholangitis: A tale of epigenetically-induced secretory failure?

Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease associated with autoimmune-related destruction of small to medium size intrahepatic bile ducts. The aetiology of PBC is unknown and its pathogenesis remains obscure. Both genetic variants and environmental factors have been linked to increased PBC susceptibility, with other alterations known to cooperate in disease pathobiology. Increasing evidence indicates the presence of epigenetic abnormalities in PBC, particularly alterations of cholangiocellular microRNAs (miRNAs or miRs). This review highlights and discusses the most relevant epigenetic alterations found in patients with PBC, focusing on the role of miR-506 in the promotion of cholestasis and immune activation.

miR-506 attenuates methylation of lncRNA MEG3 to inhibit migration and invasion of breast cancer cell lines via targeting SP1 and SP3

Background

Breast cancer has been the first death cause of cancer in women all over the world. Metastasis is believed to be the most important process for treating breast cancer. There is evidence that lncRNA MEG3 functions as a tumor suppressor in breast cancer metastasis. However, upstream regulation of MEG3 in breast cancer remain elusive. Therefore, it is critical to elucidate the underlying mechanism upstream MEG3 to regulate breast cancer metastasis.

Methods

We employed RT-qPCR and Western blot to examine expression level of miR-506, DNMT1, SP1, SP3 and MEG3. Besides, methylation-specific PCR was used to determine the methylation level of MEG3 promoter. Wound healing assay and transwell invasion assay were utilized to measure migration and invasion ability of breast cancer cells, respectively.

Results

SP was upregulated while miR-506 and MEG3 were downregulated in breast tumor tissue compared to adjacent normal breast tissues. In addition, we found that miR-506 regulated DNMT1 expression in an SP1/SP3-dependent manner, which reduced methylation level of MEG3 promoter and upregulated MEG3 expression. SP3 knockdown or miR-506 mimic suppressed migration and invasion of MCF-7 and MDA-MB-231 cells whereas overexpression of SP3 compromised miR-506-inhibited migration and invasion.

Conclusions

Our data reveal a novel axis of miR-506/SP3/SP1/DNMT1/MEG3 in regulating migration and invasion of breast cancer cell lines, which provide rationales for developing effective therapies to treating metastatic breast cancers.

MiR-506 inhibits cell proliferation, invasion, migration and epithelial-to-mesenchymal transition through targeting RWDD4 in human bladder cancer

MicroRNA (MiR)-506 serves a vital role in several types of cancer. However, the role of miR-506 in bladder cancer (BCa) progression remains to be investigated. The present study demonstrated that miR-506 expression was downregulated in BCa tissues and cell lines. Meanwhile, overexpression of miR-506 inhibited cell proliferation, migration and invasion. Additionally, upregulated miR-506 increased E-cadherin, and reduced N-cadherin and Vimentin expression levels, as markers of epithelial-to-mesenchymal transition. RWD domain containing 4 (RWDD4) was revealed to be a miR506 target in BCa cells, and the downregulation of RWDD4 was found to suppress BCa cell proliferation, migration and invasion. In summary, miR-506 may suppress the aggressive properties of human BCa cells by targeting RWDD4, and thus may be a novel therapeutic target in human BCa.

Expression levels of miR-205 and miR-506 in colon cancer tissues and their relationships with clinicopathological features

The study intended to investigate the expression levels of micro ribonucleic acid (miR)-205 and miR-506 in colon cancer tissues and their relationships with clinicopathological features. The expression levels of miR-205 and miR-506 in colon cancer tissues and para-carcinoma normal colonic mucosa tissues were detected via fluorescence reverse transcription quantitative polymerase chain reaction (RT-qPCR), and the expression levels of the two miRNAs in plasma of colon cancer patients and healthy control population were also detected. Moreover, the relationships of the two miRNAs with clinicopathological features of patients with colon cancer were analyzed. The expression levels of the two miRNAs in colon cancer tissues were higher than those in para-carcinoma normal colonic mucosa tissues, and also significantly higher in plasma of the colon cancer patients than those in the healthy control population. The differences were statistically significant (P<0.05). The expression level of miR-205 was associated with tumor-node-metastasis (TNM) staging and lymph node metastasis, while the expression level of miR-506 was associated with lymph node metastasis. The differences were statistically significant (P<0.05). The expression levels of miR-205 in the colon cancer tissues and plasma in patients had no significant correlation (r=0.467, P=0.081). There was a positive correlation between the expression levels of miR-506 in the colon cancer tissues and plasma in patients (r=0.599, P=0.038). The expression levels of miR-205 and miR-506 are upregulated in the colon cancer patients, both of which may be closely related to the occurrence and development of colon cancer, and may become potential tumor markers as well as relevant therapeutic targets.

MicroRNA-506 suppresses invasiveness and metastasis of human hepatocellular carcinoma cells by targeting IL8

MicroRNAs (miRNAs) have been reported to be involved in tumor metastasis. In this study, we investigated the function of miR-506 in the metastasis of human hepatocellular carcinoma (HCC). We found that miR-506 is significantly downregulated in the primary tissue of metastatic HCC and in highly metastatic HCC cell lines. Overexpression of miR-506 suppressed HCC cell migration, invasion, and metastasis both in vitro and in vivo. Furthermore, miR-506 was found to specifically target the 3' untranslated region (3'-UTR) of interleukin 8 (IL8) mRNA. Spearman's correlation analysis revealed that miR-506 expression inversely correlated with IL8 mRNA and protein expression in HCC tissue samples. IL8 treatment reversed miR-506-induced suppression of HCC cell migration and invasiveness. Thus, miR-506 acts as a tumor suppressor that may inhibit the migration, invasiveness, and metastasis of HCC cells by targeting IL8.

The emerging role of miR-506 in cancer

MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. They are involved in almost all biological processes, and many have been identified as potential oncogenes or tumor suppressor genes. miR-506 was recently discovered to play pivotal roles in regulating cell proliferation, differentiation, migration and invasion. Dysregulation of miR-506 has been demonstrated in multiple types of cancers; however, whether it functions as an oncogene or a tumor suppressor seems to be context-dependent. Altered miR-506 expression in cancer is caused by promoter methylation and changes in upstream transcription factors. In this review, we summarize the current understanding of the diverse roles and underlying mechanisms of miR-506 and its involvement in cancer, and suggest the potential therapeutic strategy based on miR-506.

Extensive profiling of circular RNAs and the potential regulatory role of circRNA-000284 in cell proliferation and invasion of cervical cancer via sponging miR-506

Circular RNAs (circRNAs) are key regulators in the development and progression of human cancers, however its role in cervical cancer tumorigenesis is not well understood. The present study aims to investigate the expression profiles and potential modulation of circRNA on cervical cancer carcinogenesis. Human circRNA microarray was performed to screen for abnormally expressed circRNA in cervical cancer cells and circRNA-000284 was identified as one circRNA significantly upregulated in cervical cancer cells. Subsequent mechanistic investigations suggested that knockdown of circRNA-000284 suppressed cell proliferation and invasion, and caused G0/G1 phase cell cycle arrest. By performing anti-AGO2 RNA precipitation and luciferase reporter assay, we identified miR-506 as the circRNA-000284-associated miRNA. Furthermore, Snail-2 was identified as a direct target of miR-506, and circRNA-000284 could positively regulate the expression of Snail-2. Finally, the tumor promoting effect of circRNA-000284 was abolished by co-expression of miR-506 mimics or Snail-2 silencing vector. In conclusion, circRNA-000284 promotes cell proliferation and invasion in cervical cancer, and may serve as a promising therapeutic target for cervical cancer patients. Therefore, silence of circRNA-000284 could be a future direction to develop a novel treatment strategy.

IL-1β-induced NF-κB activation down-regulates miR-506 expression to promotes osteosarcoma cell growth through JAG1

Nowadays, the role of miRNA in tumorigenesis has been largely reported. It was found that miR-506 might be associated with tumorigenesis of various cancers. The present study was aimed to investigate the character of miR-506 and some related factors in human osteosarcoma (OS) carcinogenesis. The expression level of miR-506 was downregulated in OS compared with the normal control group by RT-PCR, both in vivo and in vitro. In addition, IL-1β stimulation decreased the expression of miR-506. MiR-506 interfered with JAG1 gene transcription throughmiR-506 binding to the 3'-UTR region of JAG1 gene. Further siRNA strategy suggested that IL-1β may regulate miR-506 level via NF-κB, and then alter the JAG1 expression. Besides, the suppression of JAG1 by miR-506 inhibited OS cell proliferation. Taken together, our data indicate a process of NF-κB-induced miR-506 suppression and JAG1 upregulation upon IL-1β induction, which can be regarded as a new pathway for modulating cell proliferation via miR-506. It may be of clinical value in treating OS in the future.

miR-506 enhances the sensitivity of human colorectal cancer cells to oxaliplatin by suppressing MDR1/P-gp expression

OBJECTIVES

Chemoresistance development represents a major obstacle to the successful treatment of colorectal cancer (CRC). The aim of this study was to elucidate the mechanism by which miR-506 reverses oxaliplatin chemoresistance in CRC.

METHODS

In this study, miR-506 levels were measured in 74 patients with colon cancer via quantitative real-time polymerase chain reaction (qRT-PCR) and in situ hybridization (ISH). We subsequently analysed the relationship between miR-506 expression and CRC patient survival via the Kaplan-Meier method. MTT assay demonstrated the fractional survival rates and cell viability of HCT116-OxR, HCT116-OxR-miR-Ctrl and HCT116-OxR-miR-506 cells treated with oxaliplatin at different concentrations. Cell proliferation and apoptosis were assessed via flow cytometry (FCM) analysis and apoptosis assay. MDR1 mRNA expression and P-gp protein expression were assessed via qRT-PCR and Western blotting (WB) respectively. Immunofluorescence (IF) staining demonstrated P-gp expression in HCT116-OxR and HCT116-OxR-miR-506 cells. qRT-PCR and WB were used to detect Wnt/β-catenin pathway activity after miR-506 overexpression.

RESULTS

In the present study, in ISH and qRT-PCR results demonstrated that miR-506 is weakly expressed in chemoresistant CRC tissues. The low miR-506 expression group exhibited lower 5-year OS and lower 5-year RFS than the high miR-506 expression group. miR-506 overexpression inhibited cell growth and increased oxaliplatin-induced cell apoptosis in HCT116-OxR cells, as shown via FCM and apoptosis assay. We subsequently noted low MDR1/P-gp expression in HCT116-OxR-miR-506 cells via qRT-PCR, WB and IF. Lastly, we demonstrated low MDR1/P-gp expression in HCT116-OxR-miR-506 cells via inhibition of the Wnt/β-catenin by WB, MTT and FCM analysis.

CONCLUSION

Taken together, the findings of our study demonstrate that miR-506 overexpression in HCT116-OxR cells enhances oxaliplatin sensitivity by inhibiting MDR1/P-gp expression via down-regulation of the Wnt/β-catenin pathway and thus provide a rationale for the development of miRNA-based strategies to reverse oxaliplatin resistance in CRC cells.

Long noncoding RNA MALAT1-regulated microRNA 506 modulates ovarian cancer growth by targeting iASPP

MALAT1, an important cancer-associated long noncoding RNA (lncRNA), contributes to the development and progression of several cancers. Disordered expression of MALAT1 has been observed in several cancers, including cervical cancer, breast cancer, and ovarian cancer. However, the exact effects and molecular mechanisms of MALAT1 in ovarian cancer progression are still unknown. Here, we investigated the role of MALAT1 in human ovarian cancer cell lines and clinical tumor samples, in order to determine the function of this molecule. In our research, lncRNA-MALAT1 was specifically upregulated in ovarian cancer cell lines and promoted ovarian cancer-cell growth through targeting microRNA (miR)-506. Knockdown of MALAT1 inhibited the proliferation and DNA synthesis of human ovarian cancer cell in vitro. In addition, miR-506-dependent iASPP regulation was required in MALAT1-induced ovarian cancer-cell growth. These findings indicated that MALAT1 might suppress tumor growth via miR-506-dependent iASPP regulation. Taken together, our data indicated that MALAT1 might be an oncogenic lncRNA that promotes proliferation of ovarian cancer and could be regarded as a therapeutic target in human ovarian cancer.

MicroRNA-506 Inhibits Malignancy of Colorectal Carcinoma Cells by Targeting LAMC1

OBJECTIVE

To investigate the effects of microRNA-506 (miR-506) on malignancy of colorectal carcinoma (CRC) cells and to elucidate the underlying mechanism.

METHODS

Human colorectal carcinoma cell lines SW480, SW620, HCT116, and HT29 were served as model. Five experimental groups are established in this study, including cell control, pcDNA3 blank vector control, miR-506 over-expression, pSIH1 blank vector control, and miR-506 suppression groups. Quantitative reverse transcription PCR (qRT-PCR) assay was performed to measure miR-506 level. Transwell, Cell counting kit8 (CCK-8), and colony formation assays were performed to detect migration and invasion, viability, and colony formation abilities of CRC cell lines, respectively. Furthermore, bioinformatics method was applied to predict potential target genes of miR-506. Green fluorescent protein (GFP) reporter assays were used to verify the direct regulation of miR-506 on target mRNA in CRC cell lines. The LAMC1 mRNA and protein levels were detected by qRT-PCR and Western blot, respectively.

RESULTS

In the CRC cell lines, miR-506 level increased in the miR-506 over-expression group (P<0.05), compared with the blank vector control group. In the miR-506 over-expression group, cellular viability was significantly reduced (P<0.05). Migrated and invasive cell numbers and cell colony numbers were decreased (P<0.05). LAMC1 mRNA and protein levels in the miR-506 over-expression groups were lower than those in the control groups (P<0.05). However, there were no difference on the above indexes between pSIH1 blank vector control and miR-506 suppression groups.

CONCLUSION

miR-506 acts as a tumor suppressor and inhibits malignancy of colorectal cancer cells through directly targeting LAMC1.

miR-506 suppresses neuroblastoma metastasis by targeting ROCK1

Neuroblastoma is a complex form of cancer with highly heterogeneous clinical behavior that arises during childhood from precursor cells of the sympathetic nervous system. In patients with neuroblastoma, mortality often occurs as a result of metastasis. The disease predominantly spreads to bone marrow, with a survival rate of ~40%. The current study demonstrates that microRNA (miR)-506 directly targets and downregulates Rho-associated, coiled-coil containing protein kinase 1 (ROCK1) in transforming growth factor (TGF)-β non-canonical pathways. It may be concluded that ROCK1 contributes to the invasion and migration of neuroblastoma cells by directly downregulating miR-506; thus, leading to the upregulation of ROCK1, which promotes cell invasion and migration. The present results provide a novel understanding of how miR-506 directly regulates TGF-β non-canonical signaling.

MicroRNA-506 suppresses tumor proliferation and metastasis in colon cancer by directly targeting the oncogene EZH2

Increasing evidence reveals that aberrant expression of microRNA contributes to the development and progression of colon cancer, but the roles of microRNA-506 (miR-506) in colon cancer remain elusive. Here, we demonstrated that miR-506 was down-regulated in colon cancer tissue and cells and that miR-506 expression was inversely correlated with EZH2 expression, tumor size, lymph node invasion, TNM stage and metastasis. A high level of miR-506 identified patients with a favorable prognosis. In vitro and in vivo experiments confirmed that miR-506 inhibits the proliferation and metastasis of colon cancer, and a luciferase reporter assay confirmed that EZH2 is a direct and functional target of miR-506 via the 3′UTR of EZH2. The restoration of EZH2 expression partially reversed the proliferation and invasion of miR-506-overexpressing colon cancer cells. Moreover, we confirmed that the miR-506-EZH2 axis inhibits proliferation and metastasis by activating/suppressing specific downstream tumor-associated genes and the Wnt/β-catenin signaling pathway. Taking together, our study sheds light on the role of miR-506 as a suppressor for tumor growth and metastasis and raises the intriguing possibility that miR-506 may serve as a new potential marker for monitoring and treating colon cancer.

Overexpression of miR-506 suppresses proliferation and promotes apoptosis of osteosarcoma cells by targeting astrocyte elevated gene-1

There is increasing evidence that microRNAs (miRs) are implicated in tumor development and progression; however, their specific roles in osteosarcoma are not well understood. The aim of the present study was to investigate the role of miR-506 in the pathogenesis of osteosarcoma. The expression levels of miR-506 and astrocyte elevated gene-1 (AEG-1) mRNA were detected using quantitative polymerase chain reaction, and the protein levels of AEG-1, β-catenin, c-myc and cyclin D1 were determined using western blot analysis. The effects of miR-506 and AEG-1 on cell viability, colony forming ability and apoptosis were assessed using MTT assay, colony formation assay, and flow cytometry, respectively. Lucifer reporter assays were used to demonstrate whether AEG-1 is a direct target of miR-506. The present study identified that miR-506 was downregulated in osteosarcoma tissues and cells. Overexpression of miR-506 suppressed the proliferation and induced apoptosis in osteosarcoma cells in vitro and inhibited tumor formation in vivo. Overexpression of miR-506 significantly inhibited the luciferase activity of AEG-1 with a wild-type 3′-untranslated region, providing clear evidence that AEG-1 was a direct and functional downstream target of miR-506. Similar to the overexpression of miR-506, downregulation of AEG-1 lead to an inhibitory effect on osteosarcoma in vitro. Furthermore, overexpression of miR-506 or downregulation of AEG-1 inhibited the Wnt/β-catenin signaling pathway, and inhibition of this pathway by β-catenin small interfering RNA or CGP049090, a small molecule inhibitor, suppressed cell proliferation and induced apoptosis in vitro. Overall, the present data indicated that miR-506 functions as a tumor suppressor by targeting AEG-1 in osteosarcoma via the regulation of the Wnt/β-catenin signaling pathway.

MicroRNA-506 is up-regulated in the development of pancreatic ductal adenocarcinoma and is associated with attenuated disease progression

BACKGROUND

MicroRNA-506 (miR-506) has been reported to function in several tumors as a tumor suppressor gene or oncogene. However, the expression and role of miR-506 in pancreatic ductal adenocarcinoma (PDAC) remains unclear. In this study, we aimed to evaluate the phenotype of miR-506 in PDAC.

METHODS

Using miRNA in situ hybridization, we examined the expression of miR-506 in 113 PDACs and 87 paired normal pancreatic tissues. We evaluated miR-506 expression in PDAC cells, normal pancreatic ducts, and acinus/islands, and we analyzed the associations between miR-506 expression and the clinicopathologic characteristics of PDAC patients.

RESULTS

miR-506 expression was higher in PDAC than in matched normal pancreatic ductal cells (P < 0.001). On the other hand, the combined group of well and moderately differentiated PDACs showed higher levels of miR-506 than the poorly differentiated ones (P = 0.023). Moreover, miR-506 expression was negatively associated with pathologic T category (P = 0.004) and lymph node metastasis (P = 0.033), suggesting that miR-506 might inhibit the progression of PDAC.

CONCLUSIONS

Our results suggest that miR-506 either plays a role as an oncogene in the tumorigenesis and a tumor suppressor in the progression or serves as a house-keeping, tumor-suppressing miRNA, whose expression can be activated by oncogenic signals in early development to hinder the progression of PDAC.

miR-506 inhibits cell proliferation and invasion by targeting TET family in colorectal cancer

OBJECTIVES

Ten-eleven translocation (TET) family members have been shown to be involved in the development of many tumors. However, the biological role of the TET family and its mechanism of action in colorectal carcinogenesis and progression remain poorly understood.

MATERIALS AND METHODS

We measured the expression levels of TET family members in colorectal cancer (CRC) specimens, in the corresponding normal tissues and in cell lines using quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH). Both the protein function and the protein-independent role of TETs were investigated by cell viability assays and cell invasion assays using in vitro and in vivo models.

RESULTS

We found that all three TET genes were strongly up-regulated at the transcript level in CRC samples compared to matched normal tissues. The same results were observed in colorectal cancer cell lines. Knockdown of TETs by shTET1/2/3 showed that TET family members inhibited CRC growth and metastasis. We showed that TET family member degradation by miR-506 inhibits cell proliferation and invasion in colorectal cancer.

CONCLUSION

Through this study, we advance our understanding of the expression levels TETs and miR-506 in CRC and further clarify the internal regulatory mechanism of miR-506 by targeting TET during CRC processes. These findings may contribute to a novel avenue for researching and developing targeted therapies for CRC.

Overexpression of miR-506 inhibits growth of osteosarcoma through Snail2

Osteosarcoma (OS) is a prevalent primary bone malignancy and its distal metastasis accounts for the majority of OS-related death. MicroRNAs (miRNAs) play critical roles during cancer metastasis. Thus, elucidation of the involvement of specific miRNAs in the metastasis of OS may provide novel therapeutic targets for OS treatment. Here, we showed that in the OS specimens from patients, the levels of miR-506 were significantly decreased and the levels of Snail2 were significantly increased, compared to the paired normal bone tissue. MiR-506 and Snail2 inversely correlated in patients' specimen. Bioinformatics analyses predicted that miR-506 may target the 3'-UTR of Snail2 mRNA to inhibit its translation, which was confirmed by luciferase-reporter assay. Moreover, miR-506 overexpression inhibited Snail2-mediated cell invasiveness, while miR-506 depletion increased Snail2-mediated cell invasiveness in OS cells. Together, our data suggest that miR-506 suppression in OS cells may promote Snail2-mediated cancer metastasis.

miR-124 and miR-506 inhibit colorectal cancer progression by targeting DNMT3B and DNMT1

miR-124 and miR-506 are reportedly down-regulated and associated with tumor progression in many cancers, but little is known about their intrinsic regulatory mechanisms in colorectal cancer (CRC). In this study, we found that the miR-124 and miR-506 levels were significantly lower in human CRC tissues than in controls, as indicated by qRT-PCR and in situ hybridization histochemistry. We also found that the overexpression of miR-124 or miR-506 inhibited tumor cell progression and increased sensitivity to chemotherapy in vitro. Increased miR-124 or miR-506 expression also inhibited tumor cell proliferation and invasion in vivo. Luciferase reporter assays and western blotting were used to determine the association between miR-124, miR-506 and their target genes, DNMTs. We further identified that miR-124 and miR-506 directly targeted DNMT3B and indirectly targeted DNMT1. The overexpression of miR-124 and miR-506 reduced global DNA methylation and restored the expression of E-cadherin, MGMT and P16. In conclusion, our data showed that miR-124 and miR-506 inhibit progression and increase sensitivity to chemotherapy by targeting DNMT3B and DNMT1 in CRC. These findings may provide novel avenues for the development of targeted therapies.

MiR-506 suppresses liver cancer angiogenesis through targeting sphingosine kinase 1 (SPHK1) mRNA

MicroRNAs acting as oncogenes or tumor suppressor genes play crucial roles in human cancers. Sphingosine kinase 1 (SPHK1) and its metabolite sphingosine 1-phosphate (S1P) contribute to tumor angiogenesis. We have reported that the down-regulation of miR-506 targeting YAP mRNA results in the hepatocarcinogenesis. In the present study, we report a novel function of miR-506, which suppresses tumor angiogenesis through targeting SPHK1 mRNA in liver cancer. Bioinformatics analysis showed that miR-506 might target 3'-untranslated region (3'UTR) of SPHK1 mRNA. Then, we validated that by luciferase reporter gene assays. MiR-506 was able to reduce the expression of SPHK1 at the levels of mRNA and protein using reverse transcription-polymerase chain reaction and Western blot analysis in hepatoma HepG2 cells. Functionally, human umbilical vein endothelial cell (HUVEC) tube formation assays demonstrated that the forced miR-506 expression remarkably inhibited the production of S1P in the supernatant of hepatoma cells. The supernatant resulted in the inhibition of tumor angiogenesis. Interestingly, the supernatant with overexpression of SPHK1 could rescue the inhibition of angiogenesis of liver cancer mediated by miR-506. Anti-miR-506 increased the production of S1P in the supernatant of hepatoma cells, but the supernatant with silencing of SPHK1 abolished anti-miR-506-induced acceleration of tumor angiogenesis. Clinically, we observed that the levels of miR-506 were negatively related to those of SPHK1 mRNA in liver cancer tissues. Thus, we conclude that miR-506 depresses the angiogenesis of liver cancer through targeting 3'UTR of SPHK1 mRNA. Our finding provides new insights into the mechanism of tumor angiogenesis.

MiR-506 suppresses cell proliferation and tumor growth by targeting Rho-associated protein kinase 1 in hepatocellular carcinoma

Recent studies have shown that miR-506 plays important roles in human cancer progression. However, little is known about the function of miR-506 in hepatocellular carcinoma (HCC). In this study, we found that miR-506 significantly inhibits HCC cell proliferation in vitro and tumorigenicity in vivo. Moreover, miR-506 induced G1/S cell cycle arrest and apoptosis in HCC cells. Rho-associated protein kinase 1(ROCK1) was identified as a novel target of miR-506; overexpression of ROCK1 reversed the suppressive effects of miR-506 in HCC cells. Additionally, ROCK1 was found up-regulated and inversely correlated with miR-506 in HCC tissues. Therefore, our findings collectively suggest that miR-506 acts as a tumor suppressor via regulation of ROCK1 expression and may thus be a promising therapeutic target for HCC.

miR-506 inhibits the proliferation and invasion by targeting IGF2BP1 in glioblastoma

Increasing evidence has indicated that microRNAs (miRNAs) play an essential role in cancers. Deregulation of miR-506 was reported in several cancers. However, the expression and function of miR-506 in glioblastoma remain unclear. Our data showed that the level of miR-506 was downregulated in glioblastoma tissues and cell lines. Overexpression of miR-506 repressed cell growth, blocked G1/S transition, and suppressed cell invasion in glioblastoma cell. Moreover, IGF2BP1 was a direct target of miR-506 in glioblastoma cells. Knockdown of IGF2BP1 recapitulated the anti-proliferative and anti-invasive effects of miR-506, whereas IGF2BP1 overexpression antagonized the tumor-suppressive function of miR-506. Our data showed that miRNA-506 played a tumor suppressor gene role in human glioblastoma by regulating IGF2BP1 gene and might be a new therapeutic target of human glioblastoma.

MicroRNA-506 inhibits esophageal cancer cell proliferation via targeting CREB1

MicroRNAs (miRNAs) act as key regulators of multiple cancers. MicroRNA-506 (miR-506) functions as a tumor suppressor in various types of cancers. However, its role in esophageal cancer remains unclear. In our study, we found that miR-506 was significantly down-regulated in esophageal cancer tissues and cell lines. In vitro assay, our results showed that ectopic over-expression of miR-506 inhibited esophageal cancer cells proliferation, meanwhile, cells proliferation was promoted by miR-506 inhibition. In exploring mechanisms underlying the inhibitive role, we found that miR-506 significantly decreased the expression and transcription activity of cAMP responsive element binding protein 1 (CREB1). CREB1, tumor oncogene, exhibited significantly promote effect on esophageal cancer cell proliferation. Taken together, our data identify a new role of miR-506 in esophageal cancer involving CREB1 suppression.