MicroRNA-379 suppresses osteosarcoma progression by targeting PDK1

Reprogramming of glucose metabolism: Metabolic alterations in the progression of osteosarcoma

Metabolic reprogramming is an adaptive response of tumour cells under hypoxia and low nutrition conditions. There is increasing evidence that glucose metabolism reprogramming can regulate the growth and metastasis of osteosarcoma (OS). Reprogramming in the progress of OS can bring opportunities for early diagnosis and treatment of OS. Previous research mainly focused on the glycolytic pathway of glucose metabolism, often neglecting the tricarboxylic acid cycle and pentose phosphate pathway. However, the tricarboxylic acid cycle and pentose phosphate pathway of glucose metabolism are also involved in the progression of OS and are closely related to this disease. The research on glucose metabolism in OS has not yet been summarized. In this review, we discuss the abnormal expression of key molecules related to glucose metabolism in OS and summarize the glucose metabolism related signaling pathways involved in the occurrence and development of OS. In addition, we discuss some of the targeted drugs that regulate glucose metabolism pathways, which can lead to effective strategies for targeted treatment of OS.

circRNA-CPA4 Regulates Cell Proliferation and Apoptosis of Non-small Cell Lung Cancer via the miR-1183/PDPK1 Axis

Non-small-cell lung cancer (NSCLC) stands as a prevalent subtype of lung cancer, with circular RNAs emerging as key players in cancer development. This study elucidates the role of circRNA-CPA4 in NSCLC. Elevated circRNA-CPA4 expression in NSCLC lines was confirmed through qRT-PCR. Silencing circRNA-CPA4 with shRNA revealed, through CCK-8, colony formation, and flow cytometry assays, a notable constraint on proliferation and promotion of apoptosis in NSCLC cells. Subcellular localization analysis, RNA immunoprecipitation, and expression level assessments were employed to decipher the intricate interplay among miR-1183, circRNA-CPA4, and PDPK1. Results demonstrated heightened circRNA-CPA4 levels in NSCLC, and its knockdown curtailed NSCLC growth in vivo. Acting as a molecular sponge for miR-1183, circRNA-CPA4 regulated PDPK1 expression. Conversely, inhibiting miR-1183 counteracted the impact of circRNA-CPA4 silencing, reinstating NSCLC cell proliferation, and impeding apoptosis. Overall, this study unveils a novel mechanism: circRNA-CPA4 promotes PDPK1 expression by sequestering miR-1183, fostering NSCLC cell proliferation, and hindering apoptosis.

Master kinase PDK1 in tumorigenesis

3-phosphoinositide-dependent protein kinase 1 (PDK1) is considered as master kinase regulating AGC kinase family members such as AKT, SGK, PLK, S6K and RSK. Although autophosphorylation regulates PDK1 activity, accumulating evidence suggests that PDK1 is manipulated by many other mechanisms, including S6K-mediated phosphorylation, and the E3 ligase SPOP-mediated ubiquitination and degradation. Dysregulation of these upstream regulators or downstream signals involves in cancer development, as PDK1 regulating cell growth, metastasis, invasion, apoptosis and survival time. Meanwhile, overexpression of PDK1 is also exposed in a plethora of cancers, whereas inhibition of PDK1 reduces cell size and inhibits tumor growth and progression. More importantly, PDK1 also modulates the tumor microenvironments and markedly influences tumor immunotherapies. In summary, we comprehensively summarize the downstream signals, upstream regulators, mouse models, inhibitors, tumor microenvironment and clinical treatments for PDK1, and highlight PDK1 as a potential cancer therapeutic target.

Circ_SIPA1L1 Promotes Osteosarcoma Progression Via miR-379-5p/MAP3K9 Axis

Background: Osteosarcoma (OS) is a common malignant bone tumor. Circular RNAs (circRNAs) exert important roles in the pathogenesis of human cancers, including OS. In this study, the authors focused on the role and mechanism of circRNA signal-induced proliferation-associated 1 like 1 (circ_SIPA1L1) in OS. Methods: The enrichment of SIPA1L1, circ_SIPA1L1, microRNA-379-5p (miR-379-5p), and mitogen-activated protein kinase kinase kinase 9 (MAP3K9) was assessed by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The colony formation capacity was assessed through colony formation assay. Transwell assays were used to detect the migration and invasion abilities. Western blot assay was used to measure the expression of metastasis-related proteins and MAP3K9. The target interactions between the genes in circ_SIPA1L1/miR-379-5p/MAP3K9 axis were predicted by StarBase and confirmed by dual-luciferase reporter assay. The in vivo role of circ_SIPA1L1 was verified by murine xenograft assay. Results: Circ_SIPA1L1 abundance was aberrantly elevated in OS tissues and cell lines. Circ_SIPA1L1 accelerated the proliferation and metastasis abilities of OS cells. Circ_SIPA1L1 promoted the malignant behaviors of OS cells through elevating MAP3K9 level. MiR-379-5p directly bound to circ_SIPA1L1 and MAP3K9. MiR-379-5p interference rescued the abilities of proliferation and metastasis in OS cells, which were suppressed by the silencing of circ_SIPA1L1. Circ_SIPA1L1 promoted the development of OS via miR-379-5p/MAP3K9 in vivo. Conclusion: Circ_SIPA1L1 promoted the progression of OS via miR-379-5p/MAP3K9 axis.

Expression of microRNA-379 reduces metastatic spread of prostate cancer

Introduction

Prostate cancer (PCa) is the most common type of cancer in males, and the metastatic form is a leading cause of death worldwide. There are currently no curative treatments for this subset of patients. To decrease the mortality of this disease, greater focus must be placed on developing therapeutics to reduce metastatic spread. We focus on dissemination to the bone since this is both the most common site of metastatic spread and associated with extreme pain and discomfort for patients. Our strategy is to exploit microRNAs (miRNAs) to disrupt the spread of primary PCa to the bone.

Methods

PCa cell lines were transduced to overexpress microRNA-379 (miR-379). These transduced PCa cells were assessed using cell growth, migration, colony formation and adhesion assays. We also performed in vivo intracardiac injections to look at metastatic spread in NSG mice. A cytokine array was also performed to identify targets of miR-379 that may drive metastatic spread.

Results

PCa cells with increased levels of miR-379 showed a significant decrease in proliferation, migration, colony formation, and adhesion to bone cells in vitro. In vivo miR-379 overexpression in PC3 cells significantly decreased metastatic spread to bone and reduced levels of miR-379 were seen in patients with metastases. We identified GDF-15 to be secreted from osteoblasts when grown in conditioned media from PCa cells with reduced miR-379 levels.

Discussion

Taken together, our in vitro and in vivo functional assays support a role for miR-379 as a tumour suppressor. A potential mechanism is unravelled whereby miR-379 deregulation in PCa cells affects the secretion of GDF-15 from osteoblasts which in turn facilitates the metastatic establishment in bone. Our findings support the potential role of miR-379 as a therapeutic solution for prostate cancer.

Androgen-induced exosomal miR-379-5p release determines granulosa cell fate: cellular mechanism involved in polycystic ovaries

Polycystic ovarian syndrome (PCOS) is a complex multi-factorial syndrome associated with androgen excess and anovulatory infertility. In the current study, we investigated the role of dihydrotestosterone-induced exosomal miR-379-5p release in determining the destiny of the developing follicles. Our hypothesis was that androgen regulates granulosa cell miR-379-5p content by facilitating its exosomal release in a follicular-stage dependent manner, a process which determines granulosa cell fate. Compared to human non-PCOS subjects, individuals with PCOS exhibit higher follicular fluid free testosterone levels, lower exosomal miR-379-5p content and granulosa cell proliferation. Androgenized rats exhibited lower granulosa cell miR-379-5p but higher phosphoinositide-dependent kinase-1 (PDK1; a miR-379-5p target) content and proliferation. Androgen reduced granulosa cell miR-379-5p content by increasing its exosomal release in preantral follicles, but not in antral follicles in vitro. Studies with an exosomal release inhibitor confirmed that androgen-induced exosomal miR-379-5p release decreased granulosa cell miR-379-5p content and proliferation. Ovarian overexpression of miR-379-5p suppressed granulosa cell proliferation, and basal and androgen-induced preantral follicle growth in vivo. These findings suggest that increased exosomal miR-379-5p release in granulosa cells is a proliferative response to androgenic stimulation specific for the preantral stage of follicle development and that dysregulation of this response at the antral stage is associated with follicular growth arrest, as observed in human PCOS.

Advances of engineered extracellular vesicles-based therapeutics strategy

Extracellular vesicles (EVs) are a heterogeneous population of lipid bilayer membrane-bound vesicles which encapsulate bioactive molecules, such as nucleic acids, proteins, and lipids. They mediate intercellular communication through transporting internally packaged molecules, making them attractive therapeutics carriers. Over the last decades, a significant amount of research has implied the potential of EVs servings as drug delivery vehicles for nuclear acids, proteins, and small molecular drugs. However, several challenges remain unresolved before the clinical application of EV-based therapeutics, including lack of specificity, stability, biodistribution, storage, large-scale manufacturing, and the comprehensive analysis of EV composition. Technical development is essential to overcome these issues and enhance the pre-clinical therapeutic effects. In this review, we summarize the current advancements in EV engineering which demonstrate their therapeutic potential.

A cuproptosis-related genes signature associated with prognosis and immune cell infiltration in osteosarcoma

Osteosarcoma (OS) is one of the most prevalent primary bone tumors at all ages of human development. The objective of our study was to develop a model of Cuproptosis-Related Genes (CRGs) for predicting prognosis in OS patients. All datasets of OS patients were obtained from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database and Gene Expression Omnibus (GEO) database. We obtained the gene set (81 CRGs) related to cuproptosis by accessing the database and previous literature. All the CRGs were analyzed by univariate COX regression, least absolute shrinkage and selection operator (LASSO) COX regression analysis to screen for CRGs associated with prognosis in OS patients. Then these CRGs were used to construct a prognostic signature, which was further verified by independent cohort (GSE21257) and clinical correlation analysis. Afterward, to identify underlying mechanisms, Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used for the high-risk group by using the GSEA method. The association between the prognostic signature and 28 types of immune infiltrating cells in the tumor microenvironment was assessed. Ultimately, Lipoic Acid Synthetase (LIAS) (HR=0.632, P=0.004), Lipoyltransferase 1 (LIPT1) (HR=0.524, P=0.011), BCL2 Like 1 (BCL2L1/BCL-XL) (HR=0.593, P=0.022), and Pyruvate Dehydrogenase Kinase 1 (PDK1) (HR=0.662, P=0.025) were identified. Subsequently, they were used to calculate the risk score and build a prognostic model. In the training cohort, risk score (HR=1.878, P=0.003) could be considered as an independent prognostic factor, and OS patients with high-risk scores showed lower survival rates. Biological pathways related to substance metabolism and transport were enriched. There were significant differences in immune infiltrating cells in the tumor microenvironment. All in all, The CRGs signature is related to the tumor immune microenvironment and could be used as a credible predictor of the prognostic status in OS patients.

MiR-379-5p inhibits the proliferation, migration, and invasion of breast cancer by targeting KIF4A

BACKGROUND

Many studies have shown that microRNAs (miRNAs) play an essential role in gene regulation and tumor development. This study aimed to explore the expression of miR-379-5p and its mechanisms of affecting proliferation, migration, and invasion in breast cancer (BC).

METHODS

MiRNAs and mRNAs expression data of BC and normal breast tissue samples were downloaded from the TCGA and GEO databases. qRT-PCR was used to detect the expression of miR-379-5p in human normal breast epithelial cell lines and human BC cell lines. The proliferation ability of transfected cells was detected by colony formation and EdU assays. The mobility and invasion ability of transfected cells was measured by wound healing and transwell assays. The relative protein expression of transfected cells was detected by western blot. Dual luciferase reporter assay was performed to identify the targeted binding of miR-379-5p and KIF4A.

RESULTS

MiR-379-5p was lowly expressed in BC tissue samples and BC cell lines. The target genes of miR-379-5p were involved in many cancer-related signaling pathways. PPI analysis and the cytoHubba algorithm of Cytoscape identified 10 genes as the hub genes. Survival analysis showed that only KIF4A expression in 10 hub genes was significantly associated with the prognosis of BC patients and was significantly upregulated in BC. Overexpression of miR-379-5p inhibited proliferation, migration, and invasion in the BC cell line MDA-MB-231, which could be reversed by KIF4A.

CONCLUSIONS

MiR-379-5p inhibits proliferation, migration, and invasion of BC by targeting KIF4A.

Human umbilical cord mesenchymal stem cell-derived exosomes carrying hsa-miRNA-128-3p suppress pancreatic ductal cell carcinoma by inhibiting Galectin-3

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignant tumors of the digestive system. Many patients are diagnosed at an advanced stage and lose eligibility for surgery. Moreover, there are few effective methods for treating pancreatic ductal cell carcinoma. Increasing attention has been given to microRNAs (miRNAs) and their regulatory roles in tumor progression. In this study, we investigated the effects of exosomes extracted from human umbilical cord mesenchymal stem cells (HUCMSCs) carrying hsa-miRNA-128-3p on pancreatic cancer cells.

METHODS

Based on existing experimental and database information, we selected Galectin-3, which is associated with pancreatic cancer, and the corresponding upstream hsa-miRNA-128-3p. We extracted HUCMSCs from a fresh umbilical cord, hsa-miRNA-128-3p was transfected into HUCMSCs, and exosomes containing hsa-miRNA-128-3p were extracted and collected. The effect of exosomes rich in hsa-miRNA-128-3p on pancreatic cancer cells was analyzed.

RESULTS

The expression of Galectin-3 in normal pancreatic duct epithelial cells was significantly lower than that in PDAC cell lines. We successfully extracted HUCMSCs from the umbilical cord and transfected hsa-miRNA-128-3p into HUCMSCs. Then we demonstrated that HUCMSC-derived exosomes with hsa-miRNA-128-3p could suppress the proliferation, invasion, and migration of PANC-1 cells in vitro by targeting Galectin-3.

CONCLUSION

Hsa-miRNA-128-3p could be considered as a potential therapy for pancreatic cancer. We provided a new idea for targeted therapy of PDAC.

Mesenchymal stem cell (MSC)-derived exosomes as novel vehicles for delivery of miRNAs in cancer therapy

Mesenchymal stem cells (MSCs) are known as promising sources for cancer therapy and can be utilized as vehicles in cancer gene therapy. MSC-derived exosomes are central mediators in the therapeutic functions of MSCs, known as the novel cell-free alternatives to MSC-based cell therapy. MSC-derived exosomes show advantages including higher safety as well as more stability and convenience for storage, transport and administration compared to MSCs transplant therapy. Unmodified MSC-derived exosomes can promote or inhibit tumors while modified MSC-derived exosomes are involved in the suppression of cancer development and progression via the delivery of several therapeutics molecules including chemotherapeutic drugs, miRNAs, anti-miRNAs, specific siRNAs, and suicide gene mRNAs. In most malignancies, dysregulation of miRNAs not only occurs as a consequence of cancer progression but also is directly involved during tumor initiation and development due to their roles as oncogenes (oncomiRs) or tumor suppressors (TS-miRNAs). MiRNA restoration is usually achieved by overexpression of TS-miRNAs using synthetic miRNA mimics and viral vectors or even downregulation of oncomiRs using anti-miRNAs. Similar to other therapeutic molecules, the efficacy of miRNAs restoration in cancer therapy depends on the effectiveness of the delivery system. In the present review, we first provided an overview of the properties and potentials of MSCs in cancer therapy as well as the application of MSC-derived exosomes in cancer therapy. Finally, we specifically focused on harnessing the MSC-derived exosomes for the aim of miRNA delivery in cancer therapy.

Knowledge atlas and emerging trends on ncRNAs of osteosarcoma: A bibliometric analysis

BACKGROUND

Osteosarcoma is a common bone sarcoma that occurs in childhood and adolescence. Although research on non-coding RNAs (ncRNAs) of osteosarcoma has been developed rapidly in recent years, a specific bibliometric analysis on this topic has not yet been performed. The bibliometric analysis aims to summarize knowledge atlas, research hotspots, and emerging trends and to provide researchers with new perspectives in further studies.

METHODS

All publications regarding ncRNAs of osteosarcoma published from 2000 to 2021 were retrieved from the Web of Science Core Collection. Quantitative indicators including the number of publications and citations, H-index, and journal citation reports were analyzed by using Excel 2019 and R software. VOSviewer and CiteSpace were used to analyze the cooperation among countries/institutions/journals/authors and the co-occurrence of keywords, keywords bursts, and references.

RESULTS

A total of 3206 publications were extracted. A significant growth trend in the annual number of publications over the past 22 years is revealed (R ² = 0.999). The most prolific country and institution were China (2260) and Shanghai Jiao Tong University (134), respectively. Professors Wang W and Liu W contributed the most to this field. The keywords were stratified into six clusters: Cluster 1 (apoptosis and growth), Cluster 2 (cancer and progression), Cluster 3 (microRNAs and downregulation), Cluster 4 (genes and differentiation), Cluster 5 (expression and biological functions), and Cluster 6 (metastasis). The long non-coding RNAs and circular RNAs have been considered as an important research hotspot in the near future.

CONCLUSION

This study offers a scientific perspective on ncRNAs of osteosarcoma and provides researchers with valuable information to understand the knowledge structure and to identify emerging trends in this field.

MiR-451a Promotes Cell Growth, Migration and EMT in Osteosarcoma by Regulating YTHDC1-mediated m6A Methylation to Activate the AKT/mTOR Signaling Pathway

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It’s first proved that miR-451a can promote the malignant progression of osteosarcoma cells through AKT/mTOR pathway.

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It’s first proved that YTHDC1 modifies the m6A methylation of PDPK1.

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It’s first proved that YTHDC1 can promote the malignant progression of osteosarcoma cells.

Background

Osteosarcoma is the most prevalent primary malignant bone tumor containing mesenchymal cells with poor prognosis. Being a hot spot of anti-tumor therapy researches, AKT/mammalian target of rapamycin (mTOR) signaling pathway could affect various cellular processes including transcription, protein synthesis, apoptosis, autophagy and growth.

Materials and methods

The levels of RNA and protein were detected by quantitative real-time polymerase chain reaction (q-PCR) and western blot analyses respectively. Functional assays were carried out to analyze the malignant phenotypes of osteosarcoma cells. RNA-binding protein immunoprecipitation (RIP), Co-immunoprecipitation (Co-IP), RNA pulldown, luciferase reporter and in vitro kinase assays were conducted to uncover the specific mechanism of microRNA-451a (miR-451a) in osteosarcoma cells.

Results

Functionally, miR-451a represses the malignant progression of osteosarcoma. Mechanically, miR-451a could curb the AKT/mTOR pathway via 3-phosphoinositide dependent protein kinase 1 (PDPK1)-mediated phosphorylation modification. After the certification that YTH domain containing 1 (YTHDC1) regulates the m6A phosphorylation modification of PDPK1 mRNA, we further proved that miR-451a-mediated YTHDC1 stabilizes PDPK1 mRNA via m6A-dependent regulation.

Conclusion

This study demonstrated that miR-451a regulates YTHDC1-mediated m6A methylation to activate the AKT/mTOR pathway, stimulating the malignancy of osteosarcoma.

Positive Feedback Regulation of Circular RNA Hsa_circ_0000566 and HIF-1α promotes Osteosarcoma Progression and Glycolysis Metabolism

Hypoxia is an indispensable factor for cancer progression and is closely associated with the Warburg effect. Circular RNAs (CircRNA) have garnered considerable attention in molecular malignancy therapy as they are potentially important modulators. However, the roles of circRNAs and hypoxia in osteosarcoma (OS) progression have not yet been elucidated. This study reveals the hypoxia-sensitive circRNA, Hsa_circ_0000566, that plays a crucial role in OS progression and energy metabolism under hypoxic stress. Hsa_circ_0000566 is regulated by hypoxia-inducible factor-1α (HIF-1α) and directly binds to it as well as to the Von Hippel-Lindau (VHL) E3 ubiquitin ligase protein. Consequentially, binding between VHL and HIF-1α is impeded. Furthermore, Hsa_circ_0000566 contributes to OS progression by binding to HIF-1α (while competing with VHL) and by confers protection against HIF-1α against VHL-mediated ubiquitin degradation. These findings demonstrate the existence of a positive feedback loop formed by HIF-1α and Hsa_circ_0000566 and the key role they play in OS glycolysis. Taken together, these data indicate the significance of Hsa_circ_0000566 in the Warburg effect and suggest that Hsa_circ_0000566 could be a potential therapeutic target to combat OS progression.

Osteosarcoma and Metastasis

Osteosarcoma is the most common primary bone malignancy in adolescents. Its high propensity to metastasize is the leading cause for treatment failure and poor prognosis. Although the research of osteosarcoma has greatly expanded in the past decades, the knowledge and new therapy strategies targeting metastatic progression remain sparse. The prognosis of patients with metastasis is still unsatisfactory. There is resonating urgency for a thorough and deeper understanding of molecular mechanisms underlying osteosarcoma to develop innovative therapies targeting metastasis. Toward the goal of elaborating the characteristics and biological behavior of metastatic osteosarcoma, it is essential to combine the diverse investigations that are performed at molecular, cellular, and animal levels from basic research to clinical translation spanning chemical, physical sciences, and biology. This review focuses on the metastatic process, regulatory networks involving key molecules and signaling pathways, the role of microenvironment, osteoclast, angiogenesis, metabolism, immunity, and noncoding RNAs in osteosarcoma metastasis. The aim of this review is to provide an overview of current research advances, with the hope to discovery druggable targets and promising therapy strategies for osteosarcoma metastasis and thus to overcome this clinical impasse.

Analysis of Immune-Stromal Score-Based Gene Signature and Molecular Subtypes in Osteosarcoma: Implications for Prognosis and Tumor Immune Microenvironment

Objective: Infiltrating immune and stromal cells are essential for osteosarcoma progression. This study set out to analyze immune–stromal score-based gene signature and molecular subtypes in osteosarcoma.

Methods: The immune and stromal scores of osteosarcoma specimens from the TARGET cohort were determined by the ESTIMATE algorithm. Then, immune-stromal score-based differentially expressed genes (DEGs) were screened, followed by univariate Cox regression analysis. A LASSO regression analysis was applied for establishing a prognostic model. The predictive efficacy was verified in the GSE21257 dataset. Associations between the risk scores and chemotherapy drug sensitivity, immune/stromal scores, PD-1/PD-L1 expression, immune cell infiltrations were assessed in the TARGET cohort. NMF clustering analysis was employed for characterizing distinct molecular subtypes based on immune-stromal score-based DEGs.

Results: High immune/stromal scores exhibited the prolonged survival duration of osteosarcoma patients. Based on 85 prognosis-related stromal–immune score-based DEGs, a nine-gene signature was established. High-risk scores indicated undesirable prognosis of osteosarcoma patients. The AUCs of overall survival were 0.881 and 0.849 in the TARGET cohort and GSE21257 dataset, confirming the well predictive performance of this signature. High-risk patients were more sensitive to doxorubicin and low-risk patients exhibited higher immune/stromal scores, PD-L1 expression, and immune cell infiltrations. Three molecular subtypes were characterized, with distinct clinical outcomes and tumor immune microenvironment.

Conclusion: This study developed a robust prognostic gene signature as a risk stratification tool and characterized three distinct molecular subtypes for osteosarcoma patients based on immune–stromal score-based DEGs, which may assist decision-making concerning individualized therapy and follow-up project.

An update on the role of miR-379 in human disorders

miR-379 is a miRNA transcribed from the MIR379 locus on 14q32.31. This miRNA is located in an evolutionarily conserved miRNA cluster in an imprinted region that contains DLK1 and DIO3 genes. The mouse homolog of this miRNA has been shown to be under-expressed in response to glucocorticoid receptor deficiency. Moreover, miR-379 has a tumor-suppressive role in a wide variety of tissues including the brain, breast, lung, and liver. In addition to restraining cell proliferation and migration, miR-379 can suppress the epithelial-mesenchymal transition process. Abnormal expression of this miRNA implies the pathogenesis of Duchene muscular dystrophy, spinal cord injury, diabetic nephropathy, acute myocardial infarction, and premature ovarian failure. This review aims to the summarization of the role of miR-379 in neoplastic and non-neoplastic conditions.

MicroRNA 379 Regulates Klotho Deficiency-Induced Cardiomyocyte Apoptosis Via Repression of Smurf1

[Figure: see text].

Blocking circ-CNST suppresses malignant behaviors of osteosarcoma cells and inhibits glycolysis through circ-CNST-miR-578-LDHA/PDK1 ceRNA networks

Background

CircRNA CNST (circ-CNST) is a newly identified biomarker for prognosis of osteosarcoma (OS). However, its role in OS progression remains to be well documented.

Methods

Expression of circ-CNST, microRNA (miR)-578, lactate dehydrogenase A (LDHA), and pyruvate dehydrogenase kinase 1 (PDK1) was detected by quantitative real-time polymerase chain reaction and Western blotting. The physical interaction was confirmed by dual-luciferase reporter assay. Cell behaviors and glycolysis were measured by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay, colony formation assay, flow cytometry, transwell assays, xenograft experiment, and commercial kits.

Results

Circ-CNST was upregulated in human OS tissues and cells, accompanied with downregulation of miR-578 and upregulation of LDHA and PDK1. There were negative correlations between miR-578 expression and circ-CNST or LDHA/PDK1 in OS tissues. Moreover, high circ-CNST/LDHA/PDK1 or low miR-578 might predict shorter overall survival, advanced TNM stages, and lymph node metastasis. Physically, miR-578 was targeted by circ-CNST, and miR-578 could target LDHA/PDK1. Functionally, blocking circ-CNST and restoring miR-578 enhanced apoptosis rate and suppressed cell proliferation, colony formation, migration, and invasion in 143B and U2OS cells, accompanied with decreased glucose consumption, lactate production, and adenosine triphosphate (ATP)/adenosine diphosphate (ADP) ratio. Furthermore, in vivo growth of U2OS cells was retarded by silencing circ-CNST. Depletion of miR-578 could counteract the suppressive role of circ-CNST deficiency in 143B and U2OS cells, and restoring LDHA or PDK1 partially reversed the role of miR-578 inhibition as well.

Conclusion

Circ-CNST knockdown could antagonize malignant behaviors and glycolysis of OS cells by regulating miR-578-LDHA/PDK1 axes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02427-0.

Non-coding RNA Identification in Osteonecrosis of the Femoral Head Using Competitive Endogenous RNA Network Analysis

OBJECTIVE

To investigate the regulatory network of long non-coding RNA (lncRNA) as competing endogenous RNAs (ceRNAs) in osteonecrosis of the femoral head (ONFH).

METHODS

The gene expression profile GSE74089 of ONFH and microRNA (miRNA) expression profile of GSE89587 were obtained from the Gene Expression Omnibus (GEO) database. The GSE74089 contained four ONFH samples and four controls. The GSE89587 included 10 ONFH samples and 10 control samples. The differentially expressed lncRNAs (DE-lncRNAs) and DE-mRNAs between ONFH group and control group were identified from GSE74089 using the limma package based on criteria of adjusted P value <0.05 and |log fold change (FC)| ≥2. The DEmiRNAs between ONFH group and control group were screened from GSE89587 on the basis of adjusted P value <0.05. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway for DE-mRNAs were analyzed using DAVID 6.7 and GSEA 3.0, respectively. Coexpressed lncRNA-mRNA pairs were identified by corr.test method in R based on the criteria of adjusted P value <0.01 and |r| ≥ 0.9. A ceRNA network was constructed and visualized using cytoscape 3.7.0 by integrating the DE-lncRNA, DE-miRNA, and DEmRNA data. The key mRNAs and lncRNAs in the ceRNA network were further validated in an independent dataset of GSE123568.

RESULTS

Based on our analysis, a total of 28 DE-lncRNAs, 1403 DE-mRNAs, and 134 DE-miRNAs were identified, respectively. The DE-mRNAs were significantly enriched in the function of "skeletal system development," "collagen fibril organization," "blood vessel development," and "regulation of nervous system development." Besides, 72 KEGG pathways, including eight active pathways and 64 suppressed pathways were identified, including which immune pathway was the most significantly activated one and which ribosome-related function was the most suppressed. A co-expression network including 161 DE-mRNAs and 16 DE-lncRNAs was built. Highly connected nodes were identified among lncRNAs such as H19, C20orf203, LINC00355, SFTA3, CRNDE, CASC2, LINC00494, C9orf163, C10orf91, and LINC00301. The ceRNA network indicated that lncRNA H19 functioned as a ceRNA of hsa-miR-519b-3p and hsa-miR-296-5p in ANKH and ECHDC1 regulation; lncRNA C9orf163 functioned as a ceRNA of hsa-miR-424-5p in CCNT1 regulation. The expression trends of ANKH, CCNT1, and C9orf163 were successfully validated in independent dataset of GSE123568.

CONCLUSION

The ceRNAs of lncRNA H19- hsa-miR-519b-3p/hsa-miR-296-5p-ANKH and lncRNA c9orf163- hsa-miR-424-5p-CCNT1 might play important roles in ONFH development. Our research provided an understanding of the important role of lncRNA-related ceRNAs in ONFH.

ALKBH5 suppresses tumor progression via an m6A-dependent epigenetic silencing of pre-miR-181b-1/YAP signaling axis in osteosarcoma

ALKBH5 is the main enzyme for m⁶A-based demethylation of RNAs and it has been implicated in many biological and pathophysiological processes. Here, we aimed to explore the potential involvement of ALKBH5 in osteosarcoma and decipher the underlying cellular/molecular mechanisms. We discovered downregulated levels of demethylase ALKBH5 were correlated with increased m⁶A methylation in osteosarcoma cells/tissues compared with normal osteoblasts cells/tissues. ALKBH5 overexpression significantly suppressed osteosarcoma cell growth, migration, invasion, and trigged cell apoptosis. In contrast, inhibition of ALKBH5 produced the opposite effects. Whereas ALKBH5 silence enhanced m⁶A methylations of pre-miR-181b-1 and YAP-mRNA exerting oncogenic functions in osteosarcoma. Moreover, upregulation of YAP or downregulation of mature miR-181b-5p displayed a remarkable attenuation of anti-tumor activities caused by ALKBH5. Further results revealed that m⁶A methylated pre-miR-181b-1 was subsequently recognized by m⁶A-binding protein YTHDF2 to mediate RNA degradation. However, methylated YAP transcripts were recognized by YTHDF1 to promote its translation. Therefore, ALKBH5-based m⁶A demethylation suppressed osteosarcoma cancer progression through m⁶A-based direct/indirect regulation of YAP. Thus, ALKBH5 overexpression might be considered a new approach of replacement therapy for osteosarcoma treatment.

An update on the roles of circular RNAs in osteosarcoma

Osteosarcoma is the most common primary bone malignancy and is a neoplasm thought to be derived from the bone‐forming mesenchymal stem cells. Aberrant activation of oncogenes and inactivation of tumour suppressor genes by somatic mutations and epigenetic mechanisms play a pivotal pathogenic role in osteosarcoma. Aside from alterations in these protein‐coding genes, it has now been realized that dysregulation of non‐coding RNAs (ncRNAs), including microRNAs (miRNAs), long non‐coding RNAs (lncRNAs) and the recently discovered circular RNAs (circRNAs), is crucial to the initiation and progression of osteosarcoma. CircRNAs are single‐stranded RNAs that form covalently closed loops and function as an important regulatory element of the genome through multiple machineries. Recently, an increasing number of studies suggested that circRNAs also played critical roles in osteosarcoma. This review summarizes recent development and progression in circRNA transcriptome analysis and their functions in the modulation of osteosarcoma progression.

MicroRNA-613 alleviates IL-1β-induced injury in chondrogenic CHON-001 cells by targeting fibronectin 1

BACKGROUND

Osteoarthritis (OA) is an aging-related chronic degenerative joint disease. A number of miRNAs have been found to be involved in the development of OA, but the role of miR-613 in OA remains unclear. Thus, this study aimed to investigate the role of miR-613 during the progression of OA.

METHODS

CHON-001 cells were transfected with miR-613 agonist for 48 h, and then exposed to 10 ng/mL IL-1β for 24 h. Cell viability, cell proliferation and cell apoptosis in CHON-001 cells were assessed by CCK-8, immunofluorescence, and flow cytometry assays, respectively. In addition, the dual luciferase reporter system assay was used to determine the interaction of miR-613 and fibronectin 1 in CHON-001 cells.

RESULTS

The level of miR-613 was significantly decreased in IL-1β-treated CHON-001 cells. Overexpression of miR-613 markedly inhibited IL-1β-induced apoptosis in CHON-001 cells. In addition, upregulation of miR-613 obviously alleviated IL-1β-induced inflammatory response and cartilage matrix degradation in CHON-001 cells. Meanwhile, fibronectin 1 was identified as a direct binding target of miR-613 in CHON-001 cells. Overexpression of miR-613 alleviated IL-1β-induced injury in CHON-001 cells via downregulating the expression of fibronectin 1. Furthermore, overexpression of miR-613 alleviated cartilage degradation, and reduced OARSI scores and subchondral bone thickness in a mouse model of OA.

CONCLUSION

Our data indicated that overexpression of miR-613 could inhibit IL-1β-induced injury in CHON-001 cells via decreasing the level fibronectin 1 in vitro, and alleviate the symptoms of OA in vivo. Therefore, miR-613 might be a potential therapeutic option for the treatment of OA.

LINC01133: an emerging tumor-associated long non-coding RNA in tumor and osteosarcoma

Emerging evidence suggested that long non-coding RNAs (lncRNAs) play pivotal roles in tumorigenesis. LINC01133 is a newly identified lncRNA first discovered as an oncogene in lung squamous cell carcinoma. Subsequent studies further demonstrated this lncRNA was deregulated in a wide spectrum of tumors, including colorectal, gastric, lung, and pancreatic ductal adenocarcinoma as well as osteosarcoma and hepatocellular carcinoma. Intriguingly, this lncRNA exerted oncogenic or tumor-suppressive action in a tissue-dependent manner. This review sought to summarize our current understanding concerning the deregulation of LINC01133 in human tumors in relation to its molecular mechanisms and cellular functions. The clinical utilization of LINC01133 as a potential prognostic biomarker and a treatment target is also discussed.

Fructose-coated Angstrom silver inhibits osteosarcoma growth and metastasis via promoting ROS-dependent apoptosis through the alteration of glucose metabolism by inhibiting PDK

Osteosarcoma is a common malignant bone cancer easily to metastasize. Much safer and more efficient strategies are still needed to suppress osteosarcoma growth and lung metastasis. We recently presented a pure physical method to fabricate Ångstrom-scale silver particles (AgÅPs) and determined the anti-tumor efficacy of fructose-coated AgÅPs (F-AgÅPs) against lung and pancreatic cancer. Our study utilized an optimized method to obtain smaller F-AgÅPs and aimed to assess whether F-AgÅPs can be used as an efficient and safe agent for osteosarcoma therapy. We also investigated whether the induction of apoptosis by altering glucose metabolic phenotype contributes to the F-AgÅPs-induced anti-osteosarcoma effects. Methods: A modified method was developed to prepare smaller F-AgÅPs. The anti-tumor, anti-metastatic and pro-survival efficacy of F-AgÅPs and their toxicities on healthy tissues were compared with that of cisplatin (a first-line chemotherapeutic drug for osteosarcoma therapy) in subcutaneous or orthotopic osteosarcoma-bearing nude mice. The pharmacokinetics, biodistribution and excretion of F-AgÅPs were evaluated by testing the levels of silver in serum, tissues, urine and feces of mice. A series of assays in vitro were conducted to assess whether the induction of apoptosis mediates the killing effects of F-AgÅPs on osteosarcoma cells and whether the alteration of glucose metabolic phenotype contributes to F-AgÅPs-induced apoptosis. Results: The newly obtained F-AgÅPs (9.38 ± 4.11 nm) had good stability in different biological media or aqueous solutions and were more effective than cisplatin in inhibiting tumor growth, improving survival, attenuating osteolysis and preventing lung metastasis in osteosarcoma-bearing nude mice after intravenous injection, but were well tolerated in normal tissues. One week after injection, about 68% of F-AgÅPs were excreted through feces. F-AgÅPs induced reactive oxygen species (ROS)-dependent apoptosis of osteosarcoma cells but not normal cells, owing to their ability to selectively shift glucose metabolism of osteosarcoma cells from glycolysis to mitochondrial oxidation by inhibiting pyruvate dehydrogenase kinase (PDK). Conclusion: Our study suggests the promising prospect of F-AgÅPs as a powerful selective anticancer agent for osteosarcoma therapy.

miR-379 links glucocorticoid treatment with mitochondrial response in Duchenne muscular dystrophy

Duchenne Muscular Dystrophy (DMD) is a lethal muscle disorder, caused by mutations in the DMD gene and affects approximately 1:5000-6000 male births. In this report, we identified dysregulation of members of the Dlk1-Dio3 miRNA cluster in muscle biopsies of the GRMD dog model. Of these, we selected miR-379 for a detailed investigation because its expression is high in the muscle, and is known to be responsive to glucocorticoid, a class of anti-inflammatory drugs commonly used in DMD patients. Bioinformatics analysis predicts that miR-379 targets EIF4G2, a translational factor, which is involved in the control of mitochondrial metabolic maturation. We confirmed in myoblasts that EIF4G2 is a direct target of miR-379, and identified the DAPIT mitochondrial protein as a translational target of EIF4G2. Knocking down DAPIT in skeletal myotubes resulted in reduced ATP synthesis and myogenic differentiation. We also demonstrated that this pathway is GC-responsive since treating mice with dexamethasone resulted in reduced muscle expression of miR-379 and increased expression of EIF4G2 and DAPIT. Furthermore, miR-379 seric level, which is also elevated in the plasma of DMD patients in comparison with age-matched controls, is reduced by GC treatment. Thus, this newly identified pathway may link GC treatment to a mitochondrial response in DMD.

Profiles of immune cell infiltration and immune-related genes in the tumor microenvironment of osteosarcoma

This work aimed to investigate tumor-infiltrating immune cells (TIICs) and immune-associated genes in the tumor microenvironment of osteosarcoma. An algorithm known as ESTIMATE was applied for immune score assessment, and osteosarcoma cases were assigned to the high and low immune score groups. Immune-associated genes between these groups were compared, and an optimal immune-related risk model was built by Cox regression analyses. The deconvolution algorithm (referred to as CIBERSORT) was applied to assess 22 TIICs for their amounts in the osteosarcoma microenvironment. Osteosarcoma cases with high immune score had significantly improved outcome (P<0.01). The proportions of naive B cells and M0 macrophages were significantly lower in high immune score tissues compared with the low immune score group (P<0.05), while the amounts of M1 macrophages, M2 macrophages, and resting dendritic cells were significantly higher (P<0.05). Important immune-associated genes were determined to generate a prognostic model by Cox regression analysis. Interestingly, cases with high risk score had poor outcome (P<0.01). The areas under the curve (AUC) for the risk model in predicting 1, 3 and 5-year survival were 0.634, 0.781, and 0.809, respectively. Gene set enrichment analysis suggested immunosuppression in high-risk osteosarcoma patients, in association with poor outcome.

LINC00665 promotes breast cancer progression through regulation of the miR-379-5p/LIN28B axis

Breast cancer is the most common malignant tumor among women worldwide. Although increasing evidence indicates that long noncoding RNAs (lncRNAs) play critical roles during breast tumorigenesis and progression, the involvement of most lncRNAs in breast cancer remains largely unknown. In the current study, we demonstrated that LINC00665 promotes breast cancer cell proliferation, migration, and invasion. Accumulating evidence indicates that many lncRNAs can function as endogenous miRNA sponges by competitively binding common miRNAs. In this study, we demonstrated that LINC00665 functions as a sponge for miR-379-5p, reducing the ability of miR-379-5p to repress LIN28B. LINC00665 promoted breast cancer progression and induced an epithelial-mesenchymal transition-like phenotype via the upregulation of LIN28B expression. Clinically, LINC00665 expression was increased but miR-379-5p expression was decreased in breast cancer tissues compared with that in normal breast tissues in the TCGA database. Furthermore, the expression of LINC00665 was negatively related with miR-379-5p expression. Collectively, our results reveal the LINC00665-miR-379-5p-LIN28B axis and shed light on breast cancer therapy.

LncRNA HIF1A-AS2 promotes osteosarcoma progression by acting as a sponge of miR-129-5p

Increasing studies have demonstrated that long noncoding RNAs (lncRNAs) play vital roles in tumor development and progression. However, the relationship between osteosarcoma and HIF1AAS2 remains unknown. The expression of HIF1AAS2 and miR-129-5p was detected in osteosarcoma cell lines and samples via qRT-PCR. Cell Counting Kit-8 (CCK-8) and invasion assays were performed to determine cell proliferation and invasion ability, and a dual luciferase reporter assay was performed to determine the interaction between HIF1AAS2 and miR-129-5p. We showed that the expression of HIF1A-AS2 was upregulated in the osteosarcoma samples compared with the expression in noncancerous samples. Moreover, patients with high HIF1A-AS2 expression had a shorter overall survival. Ectopic expression of HIF1A-AS2 enhanced osteosarcoma cell proliferation, cell cycle progression and invasion. We found that overexpression of miR-129-5p decreased the luciferase activity of wild-type (WT) HIF1A-AS2 but not mutant HIF1A-AS2. Ectopic expression of HIF1A-AS2 suppressed miR-129-5p expression in MG-63 cells. We demonstrated that miR-129-5p was downregulated in osteosarcoma and was negatively associated with HIF1A-AS2 expression. Furthermore, ectopic expression of miR-129-5p suppressed osteosarcoma cell proliferation, cell cycle progression and invasion. In addition, overexpression of HIF1A-AS2 promoted cell proliferation, cell cycle progression and invasion of osteosarcoma cells through the modulation of miR-129-5p. These results indicated that HIF1A-AS2 might be a potential therapeutic target for osteosarcoma.

Emerging roles of non-coding RNAs in scoliosis

Scoliosis, a complex three‐dimensional deformity of the spine with the Cobb angle (a measure of the spinal lateral curvature) >10 degree, encompasses a spectrum of pathologies, including congenital, idiopathic, syndromic and neuromuscular aetiologies. The pathogenesis is multifactorial involving both environmental and genetic factors but the exact cellular and molecular mechanisms of disease development remain largely unknown. Emerging evidence showed that non‐coding RNAs (ncRNAs), namely microRNAs, long ncRNAs and circular RNAs, are deregulated in many orthopaedic diseases, including scoliosis. Importantly, these deregulated ncRNAs functionally participate in the initiation and progression of scoliosis. Here, we review recent progress in ncRNA research on scoliosis.

miRNA signatures in childhood sarcomas and their clinical implications

Progresses in multimodal treatments have significantly improved the outcomes for childhood cancer. Nonetheless, for about one-third of patients with Ewing sarcoma, rhabdomyosarcoma, or osteosarcoma steady remission has remained intangible. Thus, new biomarkers to improve early diagnosis and the development of precision-targeted medicine remain imperative. Over the last decade, remarkable progress has been made in the basic understanding of miRNAs function and in interpreting the contribution of their dysregulation to cancer development and progression. On this basis, this review focuses on what has been learned about the pivotal roles of miRNAs in the regulation of key genes implicated in childhood sarcomas.

miR-137 suppresses cell growth and extracellular matrixdegradation through regulating ADAMTS-5 in chondrocytes

Osteoarthritis (OA) is the most common degenerative joint disease. microRNAs (miRNAs) have been showen to act critical roles in several diseases including OA. However, the involvement and underlying mechanism of miR-137 in development of OA remains unkown. In our study, we firstly showed that IL-1β decreased the expression of miR-137 in the chondrocytes and we demonstrated that the miR-37 expression level was lower in the OA cases than in the control patients. Dual-luciferase reporter analysis was performed to confirm that ADAMTS-5 was a direct target gene of miR-137. Furthermore, we indicated that elevated expression of miR-137 decreased the protein expression of ADAMTS-5 in the chondrocytes. In additional, we showed that IL-1β induces the ADAMTS-5 expression in the chondrocytes. The ADAMTS-5 expression level was higher in the OA cases than in the control patients. We showed that the expression of ADAMTS-5 was negatively correlated with the miR-137 expression level in OA tissues. Overexpression of miR-137 suppressed cell growth, extracellular matrix (ECM) degradation and inflammation in chondrocytes. These preliminary data elucidated that miR-137 suppressed OA progression via inhibiting cell growth, inflammation and ECM degradation.

MiR-485-3p modulates neural stem cell differentiation and proliferation via regulating TRIP6 expression

Recent references have showed crucial roles of several miRNAs in neural stem cell differentiation and proliferation. However, the expression and role of miR‐485‐3p remains unknown. In our reference, we indicated that miR‐485‐3p expression was down‐regulated during NSCs differentiation to neural and astrocytes cell. In addition, the TRIP6 expression was up‐regulated during NSCs differentiation to neural and astrocytes cell. We carried out the dual‐luciferase reporter and found that overexpression of miR‐485‐3p decreased the luciferase activity of pmirGLO‐TRIP6‐wt but not the pmirGLO‐TRIP6‐mut. Ectopic expression of miR‐485‐3p decreased the expression of TRIP6 in NSC. Ectopic miR‐485‐3p expression suppressed the cell growth of NSCs and inhibited nestin expression of NSCs. Moreover, elevated expression of miR‐485‐3p decreased the ki‐67 and cyclin D1 expression in NSCs. Furthermore, we indicated that miR‐485‐3p reduced proliferation and induced differentiation of NSCs via targeting TRIP6 expression. These data suggested that a crucial role of miR‐485‐3p in self‐proliferation and differentiation of NSCs. Thus, altering miR‐485‐3p and TRIP6 modulation may be one promising therapy for treating with neurodegenerative and neurogenesis diseases.

MicroRNA-503 Inhibits Non-Small Cell Lung Cancer Progression By Targeting PDK1/PI3K/AKT Pathway

OBJECTIVES

The aim of the study was to study the role of dysregulated expression of a microRNA (miRNA), miR-503, in non-small-cell lung cancer (NSCLC) and investigate the underlying mechanism.

METHODS

Quantitative real-time PCR (qRT-PCR) and in situ hybridization staining (ISH) were used to evaluate the expression level of miR-503 in NSCLC tissues and paired adjacent tissues. CCK-8, colony formation and flow cytometry were performed to explore the effects of miR-503 overexpression on cell proliferation, colony formation and apoptosis. Cells with miR-503 overexpression were used to initiate xenograft models. Dual luciferase reporter assay, qRT-PCR, immunohistochemistry and Western blotting were conducted to investigate the interaction of miR-503 and its potential target.

RESULTS

Significantly downregulated miR-503 was found in NSCLC tumor tissues and cell lines. miR-503 overexpression significantly inhibited NSCLC cell proliferation, migration and invasion. PDK1 was predicted as the direct targets of miR-503. PDK1 overexpression reversed the inhibitory effects of miR-503 on biological functions, while PDK1 silencing significantly counteracted miR-503 inhibitor-induced pro-tumor effects in A549 cells. Mechanistically, upregulation of miR-503 inhibited PDK1 expression and subsequently caused the inactivation of PI3K/AKT pathway.

CONCLUSION

Our results suggest that miR-503 inhibits NSCLC progression by targeting PDK1/PI3K/AKT pathway, potentiating the use of miR-503 as a biomarker and therapeutic target for NSCLC.

Clinical value of non-coding RNAs in cardiovascular, pulmonary, and muscle diseases

Although a majority of the mammalian genome is transcribed to RNA, mounting evidence indicates that only a minor proportion of these transcriptional products are actually translated into proteins. Since the discovery of the first non-coding RNA (ncRNA) in the 1980s, the field has gone on to recognize ncRNAs as important molecular regulators of RNA activity and protein function, knowledge of which has stimulated the expansion of a scientific field that quests to understand the role of ncRNAs in cellular physiology, tissue homeostasis, and human disease. Although our knowledge of these molecules has significantly improved over the years, we have limited understanding of their precise functions, protein interacting partners, and tissue-specific activities. Adding to this complexity, it remains unknown exactly how many ncRNAs there are in existence. The increased use of high-throughput transcriptomics techniques has rapidly expanded the list of ncRNAs, which now includes classical ncRNAs (e.g., ribosomal RNAs and transfer RNAs), microRNAs, and long ncRNAs. In addition, splicing by-products of protein-coding genes and ncRNAs, so-called circular RNAs, are now being investigated. Because there is substantial heterogeneity in the functions of ncRNAs, we have summarized the present state of knowledge regarding the functions of ncRNAs in heart, lungs, and skeletal muscle. This review highlights the pathophysiologic relevance of these ncRNAs in the context of human cardiovascular, pulmonary, and muscle diseases.

Somatic Mutations in miRNA Genes in Lung Cancer-Potential Functional Consequences of Non-Coding Sequence Variants

A growing body of evidence indicates that miRNAs may either drive or suppress oncogenesis. However, little is known about somatic mutations in miRNA genes. To determine the frequency and potential consequences of miRNA gene mutations, we analyzed whole exome sequencing datasets of 569 lung adenocarcinoma (LUAD) and 597 lung squamous cell carcinoma (LUSC) samples generated in The Cancer Genome Atlas (TCGA) project. Altogether, we identified 1091 somatic sequence variants affecting 522 different miRNA genes and showed that half of all cancers had at least one such somatic variant/mutation. These sequence variants occurred in most crucial parts of miRNA precursors, including mature miRNA and seed sequences. Due to our findings, we hypothesize that seed mutations may affect miRNA:target interactions, drastically changing the pool of predicted targets. Mutations may also affect miRNA biogenesis by changing the structure of miRNA precursors, DROSHA and DICER cleavage sites, and regulatory sequence/structure motifs. We identified 10 significantly overmutated hotspot miRNA genes, including the miR-379 gene in LUAD enriched in mutations in the mature miRNA and regulatory sequences. The occurrence of mutations in the hotspot miRNA genes was also shown experimentally. We present a comprehensive analysis of somatic variants in miRNA genes and show that some of these genes are mutational hotspots, suggesting their potential role in cancer.

LncRNA Linc00511 promotes osteosarcoma cell proliferation and migration through sponging miR-765

Long noncoding RNA (lncRNA) Linc00511 is a novel lncRNA, and it was reported to play important roles in the progression and carcinogenesis of several tumors. However, the expression and biological roles of Linc00511 in osteosarcoma were still unknown. In this research, we showed that the expression of Linc00511 was upregulated in osteosarcoma samples and cell lines. Ectopic expression of Linc00511 promoted osteosarcoma cell growth, colony formation, and migration. Moreover, overexpression of Linc00511 enhanced the epithelial-mesenchymal transition progression in osteosarcoma cell. In addition, we showed that elevated expression of Linc00511 suppressed microRNA-765 (miR-765) expression and promoted apurinic/apyrimidinic endonuclease 1 (APE1) expression in osteosarcoma cell. The expression of miR-765 was downregulated in osteosarcoma cells and samples and was negatively related to Linc00511 expression in osteosarcoma tissues. Ectopic expression of miR-765 inhibited osteosarcoma cell growth and migration. Furthermore, we showed that Linc00511 overexpression promoted MG-63 cells proliferation, colony formation, and migration via downregulation of miR-765. These results suggested that Linc00511 played as an oncogene in the development of osteosarcoma.

Melatonin protected against the detrimental effects of microRNA-363 in a rat model of vitamin A-associated congenital spinal deformities: Involvement of Notch signaling

Congenital spinal deformities are a result of defective somitogenesis and are associated with vitamin A deficiency (VAD). However, the molecular mechanisms of VAD-associated congenital spinal deformities remain largely unknown. Increasing number of studies suggested that microRNAs and melatonin played important roles in the development of congenital spinal deformities. In this study, we showed that the whole-embryo expression of miR-363 was upregulated in VAD rats. Furthermore, we demonstrated that miR-363 inhibited the proliferation and neuronal differentiation of primary cultured NSCs, accompanied by downregulation of Notch1. To this end, melatonin suppressed miR-363 expression and rescued the effects of miR-363 on NSC proliferation and neuronal differentiation together with restoration of Notch signaling. The present study provided new insights into the mechanism of VAD-associated spinal deformities and the therapeutic effect of melatonin that may lead to novel understanding of the molecular mechanisms of congenital spinal deformities.

miR-202 modulates the progression of neuropathic pain through targeting RAP1A

Neuropathic pain is a somatosensory disorder which is caused by disease or nerve injury that affects the nervous system. microRNAs (miRNAs) are proved to play crucial roles in the development of neuropathic pain. However, the role of miR-202 in neuropathic pain is still unknown. Sprague-Dawley rats were used for constructing the neuropathic pain model. The expression of miR-202 was determined by quantitative real-time polymerase chain reaction. Potential target gene for miR-202 was measured using bioinformatics methods and Western blot analysis. In this study, we used rats to establish a neuropathic pain model and measured the effect of miR-202 in neuropathic pain. We demonstrated that miR-202 expression was downregulated in the spinal dorsal horn of bilateral sciatic nerve chronic constriction injury (bCCI) rat. However, miR-202 expression was not changed in the dorsal root ganglion, hippocampus, and anterior cingulated cortex of bCCI rat. We identified that RAP1A was a direct target gene of miR-202 in the PC12 cell. RAP1A expression was upregulated in the spinal dorsal horn of bCCI rat. Overexpression of miR-202 could improve the pain threshold for bCCI rats in both hindpaws, indicating that miR-202 overexpression could lighten the pain threshold for model rats. Moreover, RAP1A overexpression increased the pain threshold effect of miR-202 overexpression treated bCCI rats, indicating that miR-202 could lighten the pain threshold through inhibiting RAP1A expression. These data suggested that miR-202 acted pivotal roles in the development of neuropathic pain partly through targeting RAP1A gene.

Oncogenic and Tumor-Suppressive Roles of MicroRNAs with Special Reference to Apoptosis: Molecular Mechanisms and Therapeutic Potential

MicroRNAs (miRNAs) are the non-coding class of minute RNA molecules that negatively control post-transcriptional regulation of various functional genes. These miRNAs are transcribed from the loci present in the introns of functional or protein-coding genes, exons of non-coding genes, or even in the 3'-untranslated region (3'-UTR). They have potential to modulate the stability or translational efficiency of a variety of target RNA [messenger RNA (mRNA)]. The regulatory function of miRNAs has been elucidated in several pathological conditions, including neurological (Alzheimer's disease and Parkinson's disease) and cardiovascular conditions, along with cancer. Importantly, miRNA identification in cancer progression and invasion has evolved as an incipient era in cancer treatment. Several studies have shown the influence of miRNAs on various cancer processes, including apoptosis, invasion, metastasis and angiogenesis. In particular, apoptosis induction in tumor cells through miRNA has been extensively studied. The biphasic mode (up- and down-regulation) of miRNA expression in apoptosis and other cancer processes has already been determined. The findings of these studies could be utilized to develop potential therapeutic strategies for the management of various cancers. The present review critically describes the oncogenic and tumor suppressor role of miRNAs in apoptosis and other cancer processes, therapy resistance, and use of their presence in the body fluids as biomarkers.

miR-491-5p inhibits osteosarcoma cell proliferation by targeting PKM2

Increasing evidence has indicated that microRNAs (miRNAs/miRs) are associated with tumorigenesis and the development of numerous cancer types. Previous studies have suggested miRNA-491-5p is downregulated in osteosarcoma (OS) and functions as a tumor suppressor. However, the biological roles and underlying mechanisms associated with miR-491-5p function in OS require further exploration. In the present study, it was demonstrated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) that miR-491-5p was downregulated in 36 pairs of OS tissues, compared with in adjacent normal bone tissues. Furthermore, CCK-8 and colony formation assays indicated that miR-491-5p mimics suppressed OS cell proliferation. However, an miR-491-5p inhibitor enhanced cell proliferation. In addition, luciferase reporter assays, RT-qPCR and western blot analysis demonstrated that PKM2 was a direct target of miR-491-5p. The miR-491-5p mimic inhibited the mRNA and protein expression of PKM2, while the miR-491-5p inhibitor promoted PKM2 mRNA and protein expression. In addition, PKM2 overexpression reversed the proliferation-inhibiting effects of miR-491-5p in OS cells. Therefore, these results indicated that miR-491-5p serves as a tumor suppressor in OS cells, which may be important in OS treatment.

MicroRNA-379 suppresses cell proliferation, migration and invasion in nasopharyngeal carcinoma by targeting tumor protein D52

MicroRNAs (miRs) have been demonstrated to be important regulators of malignant behavior in nasopharyngeal carcinoma (NPC) tumorigenesis. The present study aimed to investigate the biological roles and underlying mechanisms of miR-379 in NPC. The study initially observed that miR-379 was significantly downregulated in NPC clinical tissues and cell lines using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Next, gain-of-function assays were performed on human the NPC cell lines, C666-1 and 5-8F, including MTT, colony formation and transwell migration assays. The results indicated that ectopic expression of miR-379 suppressed the NPC cell proliferation, colony formation, migration and invasion in vitro. In addition, tumor protein D52 (TPD52) was identified as a direct target of miR-379 by a dual-luciferase reporter assay, while overexpression of miR-379 markedly reduced TPD52 expression at the mRNA and protein levels, as determined by RT-qPCR and western blot analysis, respectively. Furthermore, silencing of TPD52 significantly inhibited the C666-1 cell proliferation, migration and invasion. These findings suggest that miR-379 negatively regulates the growth and migration of NPC cells by downregulating TPD52 expression, while modulation of miR-379 expression may be a therapeutic strategy for NPC.

Employing mesenchymal stem cells to support tumor-targeted delivery of extracellular vesicle (EV)-encapsulated microRNA-379

Adult Mesenchymal Stem Cells (MSCs) have a well-established tumor-homing capacity, highlighting potential as tumor-targeted delivery vehicles. MSCs secrete extracellular vesicle (EV)-encapsulated microRNAs, which play a role in intercellular communication. The aim of this study was to characterize a potential tumor suppressor microRNA, miR-379, and engineer MSCs to secrete EVs enriched with miR-379 for in vivo therapy of breast cancer. miR-379 expression was significantly reduced in lymph node metastases compared to primary tumor tissue from the same patients. A significant reduction in the rate of tumor formation and growth in vivo was observed in T47D breast cancer cells stably expressing miR-379. In more aggressive HER2-amplified HCC-1954 cells, HCC-379 and HCC-NTC tumor growth rate in vivo was similar, but increased tumor necrosis was observed in HCC-379 tumors. In response to elevated miR-379, COX-2 mRNA and protein was also significantly reduced in vitro and in vivo. MSCs were successfully engineered to secrete EVs enriched with miR-379, with the majority found to be of the appropriate size and morphology of exosomal EVs. Administration of MSC-379 or MSC-NTC cells, or EVs derived from either cell population, resulted in no adverse effects in vivo. While MSC-379 cells did not impact tumor growth, systemic administration of cell-free EVs enriched with miR-379 was demonstrated to have a therapeutic effect. The data presented support miR-379 as a potent tumor suppressor in breast cancer, mediated in part through regulation of COX-2. Exploiting the tumor-homing capacity of MSCs while engineering the cells to secrete EVs enriched with miR-379 holds exciting potential as an innovative therapy for metastatic breast cancer.

MicroRNA-379 Suppresses Cervical Cancer Cell Proliferation and Invasion by Directly Targeting V-crk Avian Sarcoma Virus CT10 Oncogene Homolog-Like (CRKL)

Cervical cancer is the fourth most common malignancy among females worldwide. MicroRNA-379 (miR-379) is aberrantly expressed in multiple human cancer types. However, the expression pattern, roles, and detailed regulatory mechanisms of miR-379 in cervical cancer remain unknown. In this study, we found that miR-379 expression was downregulated in cervical cancer tissues and cell lines. Low miR-379 expression was correlated with International Federation of Gynecology and Obstetrics (FIGO) stage, lymph node metastasis, and distant metastasis. Additionally, miR-379 overexpression suppressed the proliferation and invasion of cervical cancer cells. Furthermore, V-crk avian sarcoma virus CT10 oncogene homolog-like (CRKL) was identified as a direct target of miR-379 in cervical cancer. CRKL was upregulated in cancer tissues and negatively correlated with miR-379 expression. Moreover, restored CRKL expression rescued the inhibitory effects of miR-379 overexpression on cell proliferation and invasion. In conclusion, miR-379 may serve as a tumor suppressor in cervical cancer by directly targeting CRKL. Restoring miR-379 expression may be an effective strategy for the treatment of cervical cancer.

MicroRNA-379 inhibits cell proliferation and invasion in glioma via targeting metadherin and regulating PTEN/AKT pathway

Numerous microRNAs (miRNAs) are aberrantly expressed in glioma, and implicated in glioma occurrence and development. Therefore, the development of miRNAs as potential therapeutic targets for the treatment of patients with glioma has been proposed. miR‑379 has been shown to be aberrantly expressed in the progression of malignant tumours. However, the expression, biological functions and mechanism of miR‑379 in glioma are yet to be fully understood. Hence, the present study aimed to detect miR‑379 expression, investigate its functional relevance and explore its associated molecular mechanism in glioma. In this study, miR‑379 expression was significantly downregulated in glioma tissues and cell lines. Enforced miR‑379 expression markedly suppressed the cell proliferation and invasion of glioma. Metadherin (MTDH) was identified as a direct target of miR‑379 in glioma. The miR‑379 expression and MTDH mRNA levels exhibited an inverse association in glioma tissues. The restoration of the MTDH expression partially rescued the inhibitory effects of miR‑379 overexpression on glioma cell proliferation and invasion, and the upregulation of miR‑379 inhibited the activation of phosphatase and tensin homolog (PTEN)/AKT serine/threonine kinase (AKT) signaling pathway. Overall, these findings demonstrated that miR‑379 may play tumour‑suppressing roles in glioma through downregulation of MTDH and regulation of the PTEN/AKT signaling pathway, suggesting that miR‑379 might be a possible target for the treatment of patients with this malignancy.

Circulating microRNA signature of steroid-induced osteonecrosis of the femoral head

OBJECTIVES

Steroid-induced osteonecrosis of the femoral head (ONFH) is a common orthopaedic disease of which early detection remains clinically challenging. Accumulating evidences indicated that circulating microRNAs (miRNAs) plays vital roles in the development of several bone diseases. However, the association between circulating miRNAs and steroid-induced ONFH remains elusive.

MATERIALS AND METHODS

miRNA microarray was performed to identify the differentially abundant miRNAs in the serums of systemic lupus erythematosus (SLE) patients with steroid-induced ONFH as compared with SLE control and healthy control group. We predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA-mRNA interactions.

RESULTS

Our data indicated that there were 11 differentially abundant miRNAs (2 upregulated and 9 downregulated) between SLE-ONFH group and healthy control group and 42 differentially abundant miRNAs (14 upregulated and 28 downregulated) between SLE-ONFH group and SLE control group. We also predicted the potential functions of these differentially abundant miRNAs using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses and reconstructed the regulatory networks of miRNA-mRNA interactions.

CONCLUSIONS

These findings corroborated the idea that circulating miRNAs play significant roles in the development of ONFH and may serve as diagnostic markers and therapeutic targets.

Emerging roles of MicroRNAs in osteonecrosis of the femoral head

Osteonecrosis of the femoral head (ONFH) is one of the most common orthopaedic diseases. The exact pathogenic mechanism of ONFH is still unknown. MicroRNAs (miRNAs) are a class of non-coding RNAs that negatively modulate gene expression at post-transcriptional level. An increasing number of studies have shown that miRNAs play crucial roles in different physiological processes, including development, cell proliferation, differentiation and metabolism. Recently, multiple studies demonstrated that miRNAs are involved in the pathogenesis of ONFH. In this review, we summarize dysregulated miRNAs and their functions in ONFH. Furthermore, we discuss their potential clinical applications for diagnosis and treatment of ONFH.

MicroRNA-379 acts as a tumor suppressor in non-small cell lung cancer by targeting the IGF‑1R-mediated AKT and ERK pathways

Lung cancer is one of the most common types of malignancy in humans and is a leading cause of cancer-related deaths among men and women worldwide. Aberrantly expressed microRNAs in non-small cell lung cancer (NSCLC) contribute to tumor occurrence and development as either tumor suppressors or promoters. MicroRNA-379 (miR‑379) is dysregulated in several types of human cancer. However, its expression pattern, role and underlying mechanism in NSCLC progression and metastasis are poorly understood. In this study, assay of reverse transcription-quantitative polymerase chain reaction showed that miR‑379 was downregulated in both NSCLC tissue and cell lines. Low miR‑379 expression in NSCLC tissues was significantly correlated with TNM stage and lymph node metastasis. In addition, functional experiments revealed that restoring the expression of miR‑379 inhibited cell proliferation, migration and invasion of NSCLC. The insulin-like growth factor receptor-1 (IGF‑1R) was identified as a direct target of miR‑379 in NSCLC. IGF‑1R was highly expressed in NSCLC tissues and inversely correlated with miR‑379 expression. Downregulation of IGF‑1R had tumor suppressive roles similar to that of miR‑379 overexpression on NSCLC cell proliferation, migration and invasion. Moreover, the upregulation of IGF‑1R effectively rescued the tumor suppressive roles induced by miR‑379 overexpression in NSCLC. The resumption of the expression of miR‑379 inhibited the activation of AKT and ERK signaling pathways in NSCLC. These findings suggested that miR‑379 acts as a tumor suppressor in NSCLC by directly targeting IGF‑1R and indirectly regulating AKT and ERK signaling pathways. miR‑379 provides novel therapeutic targets for the treatment of patients with this disease.