microRNA and Bone Cancer

Tumor-suppressive microRNA-152 inhibits the proliferation of Ewing's sarcoma cells by targeting CDK5R1

We elucidated the mechanism through which the reduced expression of miR-152 leads to the overexpression of its target cyclin-dependent kinase-5 activator 1 (CDK5R1) in Ewing's sarcoma (ES) cells and the role of this mechanism in the proliferation of ES cells. To explore possible oncogenic factors in ES, we conducted microarray-based investigation and profiled the changes in miRNA expression and their effects on downstream mRNAs in five ES cell lines and human mesenchymal stem cells (hMSCs). miR-152 was significantly downregulated, while cyclin-dependent kinase-5 activator 1 (CDK5R1) expression was significantly upregulated in all tested ES cells as compared to hMSCs. The overexpression of CDK5R1 led to the activation of CDK5, enabling the phosphorylation of retinoblastoma protein and persistent overexpression of CCNE. Moreover, miR-152 suppressed cell proliferation via cell cycle retardation, and its upregulation reduced tumor size and CCNE expression in tumor tissues. The overexpression of cyclin E (CCNE) has been detected in ES cells, but the detailed mechanisms have not been previously elucidated. These findings identify the miR152-CDK5R1 signaling axis as a critical mechanism for tumorigenesis that may serve as a new therapeutic target in Ewing's sarcoma. We believe that our results will aid in the development of effective treatment strategies for patients with ES.

Oncomeric Profiles of microRNAs as New Therapeutic Targets for Treatment of Ewing's Sarcoma: A Composite Review

Ewing's sarcoma is a rare type of cancer that forms in bones and soft tissues in the body, affecting mostly children and young adults. Current treatments for ES are limited to chemotherapy and/or radiation, followed by surgery. Recently, microRNAs have shown favourable results as latent diagnostic and prognostic biomarkers in various cancers. Furthermore, microRNAs have shown to be a good therapeutic agent due to their involvement in the dysregulation of various molecular pathways linked to tumour progression, invasion, angiogenesis, and metastasis. In this review, comprehensive data mining was employed to explore various microRNAs that might have therapeutic potential as target molecules in the treatment of ES.

Construction of a Diagnostic Model for Distinguishing Benign or Malignant Bone Cancer by Mining miRNA Expression Data

Bone tumor is a kind of rare cancer, the location of which is mainly in bone tissue as well as cartilage tissue. Bone tumor is mainly classified into benign and malignant types. The survival rate of patients with bone tumors can be considerably improved by early detection, and the danger of amputation caused by bone tumors can be greatly reduced. In this study, we first screened the top 25% serum miRNAs with the greatest variance in patients with malignant and benign bone tumor and healthy individuals. The expression of serum miRNAs in patients with bone tumor was then examined using unsupervised clustering and PCA, and the results revealed that the overall expression of serum miRNAs was ineffective in distinguishing patients with benign/malignant bone tumors. Subsequently, we screened 19 miRNA biomarkers that could be used to determine the benign/malignant bone tumor of patients by LASSO logistic regression. These genes were validated using ROC curves. Results showed that there were 11 miRNAs that could accurately distinguish benign/malignant bone tumor alone. These 11 miRNAs were, namely, hsa-miR-192-5p, hsa-miR-137, hsa-miR-142-3p, hsa-miR-155-3p, hsa-miR-1205, hsa-miR-1273a, hsa-miR-3187-3p, hsa-miR-1255b-2-3p, hsa-miR-1288-5p, hsa-miR-6836-5p, and hsa-miR-6862-5p. Next, we established a diagnostic model using logistic regression and validated the diagnostic model using ROC curves; the result of which showed that the model had good diagnostic efficacy. Then, we also verified that the diagnostic model established by these 11 miRNAs could distinguish patients with benign/malignant bone tumor using unsupervised clustering as well as PCA. Finally, by using qPCR, we validated the expression of 11 miRNAs in the serum of patients with malignant and benign bone tumors, as well as healthy volunteers. The results were consistent with the trend of miRNAs expression in public databases. In summary, we examined the differential expression of serum miRNAs in individuals with benign and malignant bone tumors and discovered 11 miRNA biomarkers that could be utilized to discriminate between the two.

The Biological Function of MicroRNAs in Bone Tumors

Micro ribonucleic acids (miRNAs) are small endogenous noncoding RNAs molecules that regulate gene expression post-transcriptionally. A single miRNA is able to target hundreds of specific messenger RNA (mRNAs) by binding to the 3′-untranslated regions. miRNAs regulate different biological processes such as cell proliferation, differentiation and apoptosis. Altered miRNA expression is certainly related to the development of the most common human diseases, including tumors. Osteosarcoma (OS), Ewing’s Sarcoma (ES), and Chondrosarcoma (CS) are the most common primary bone tumors which affect mainly children and adolescents. A significant dysregulation of miRNA expression, in particular of mir-34, mir-21, mir-106, mir-143, and miR-100, has been revealed in OS, ES and CS. In this context, miRNAs can act as either tumor suppressor genes or oncogenes, contributing to the initiation and progression of bone tumors. The in-depth study of these small molecules can thus help to better understand their biological functions in bone tumors. Therefore, this review aims to examine the potential role of miRNAs in bone tumors, especially OS, ES and CS, and to suggest their possible use as potential therapeutic targets for the treatment of bone tumors and as biomarkers for early diagnosis.

Local delivery and controlled release of miR-34a loaded in hydroxyapatite/mesoporous organosilica nanoparticles composite-coated implant wire to accelerate bone fracture healing

Immediate mechanical stability is a prerequisite for fracture healing. In addition to bringing immediate mechanical stability in fracture site, implants with bioactive coating can release active substance to accelerate bone-fracture healing. However, limited drug-loading capacity of established coatings weakens their biological functions, which urges the engineering of more effective coating biomaterials for accelerating fracture healing. Herein, mesoporous organosilica nanoparticles (MONs), as miR-34a delivers, are loaded onto hydroxyapatite (HA)-coated Kirschner wire to engineer a HA/MONs@miR-34a composite coating. The composite coating can effectively deliver miR-34a into osteoclasts, generate gene dose-dependent inhibiting effect on differentiation and resorptive activity of osteoclasts by regulating multiple downstream gene expression at the early stage of fracture healing, which additionally exhibits decent bone regeneration potentials as evidenced in rat tibial fracture model. In particular, differentially expressed genes regulated by miR-34a are identified using RNA-seq followed by bioinformatics analysis. Functional enrichment analysis reveals that genes with altered expression mainly distribute in mainly distribute in DNA replication and cell cycle, which are associated with the development of osteoclasts. This work not only demonstrates the high clinical translation potential of HA/MONs@miR-34a to accelerate fracture healing, but also reveals the underlying molecular mechanism of regulating physiological functions of osteoclasts based on analysis of singlecell RNA sequencing.

MicroRNA-382-5p inhibits osteosarcoma development and progression by negatively regulating VEZF1 expression

Human osteosarcoma is the most frequent malignant primary bone tumor that mainly occurs in young adults and children. MicroRNAs (miRNAs/miRs) are abnormally expressed in human osteosarcoma and contribute to osteosarcoma initiation and development. The present study aimed to investigate the role of miR-382-5p in the nosogenesis of osteosarcoma and to identify a novel target for osteosarcoma treatment. miR-382-5p expression was detected in human osteosarcoma clinical tissues and cell lines, including 143B, U2OS and MG63, via reverse transcription-quantitative PCR analysis. Multiple bioinformatic prediction toowe used to identify the potential target genes of miR-382-5p and vascular endothelial zinc finger 1 (VEZF1), which were validated via the dual-luciferase reporter assay. MG63 and U2OS cells were transfected with miR-382-5p mimics. The Cell Counting Kit-8 assay was performed to assess cell proliferation, while the Transwell assay was performed to assess migration and invasion. Cell colony formation was measured via crystal violet staining, and apoptosis was assessed via Annexin V/propidium iodide staining. The wound healing assay was performed to assess the migratory ability of U2OS and MG63 cells. Antitumor effects of miR-382-5p were evaluated in nude mice xenografts using U2OS cells. The results demonstrated that miR-382-5p expression was markedly downregulated in human osteosarcoma tissues and cell lines compared with adjacent normal tissues. Transfection of miR-382-5p mimics into MG63 and U2OS cells significantly inhibited the malignant behaviors of cells, including decreased proliferation, migration, diminished colony formation and invasion, and promoted osteosarcoma cell apoptosis. Bioinformatics prediction indicated that VEZF1 is a direct target gene of miR-382-5p. Overexpression of VEZF1 restored osteosarcoma tumor development inhibited by miR-382-5p in vivo. In addition, overexpression of miR-382-5p restrained the growth of xenograft osteosarcoma in nude mice following co-transfection, and overexpression of VEZF1 attenuated the inhibitory effect of miR-382-5p in nude mice. miR-382-5p acted as a tumor suppressor gene and inhibited the malignant biological behaviors of human osteosarcoma cells and functions associated with directly targeting VEZF1. Taken together, these results suggest that the miR-382-5p/VEZF1 interaction has an important role in osteosarcoma development and progression, and thus may be used as a diagnostic and therapeutic target for osteosarcoma.

MicroRNA-545-5p regulates apoptosis, migration and invasion of osteosarcoma by targeting dimethyladenosine transferase 1

The metastasis of osteosarcoma is a major threat to both adolescents and young adults. Identifying novel targets that may prevent osteosarcoma metastasis is critical in developing advanced clinical therapies for treating this cancer. The present study aimed to explore the mechanism of microRNA (miR)-545-5p in the metastasis of osteosarcoma. The present study identified miR-545-5p as a potential target that was downregulated in both osteosarcoma clinical samples and cell lines, and in the latter, ectopically expressed miR-545-5p caused apoptosis. In addition, miR-545-5p exerted inhibitory effects in osteosarcoma migration and invasion. Overexpression of miR-545-5p induced xenograft growth inhibition in vivo. In addition, miR-545-5p targeted dimethyladenosine transferase 1 (DIMT1), an oncogenic protein that facilitates osteosarcoma proliferation, migration and invasion. Taken together, the results of the present study suggest that miR-545-5p functions as a tumor suppressor in osteosarcoma that promotes apoptosis, while inhibiting migration and invasion by targeting DIMT1. Taken together, the results of the present study suggest two potential novel targets for osteosarcoma treatment and metastasis prevention.

Osteosarcoma, chondrosarcoma and Ewing sarcoma: Clinical aspects, biomarker discovery and liquid biopsy

Bone sarcomas, although rare, are associated with significant morbidity and mortality. The most frequent primary bone cancers include osteosarcoma, chondrosarcoma and Ewing sarcoma. The treatment approaches are heterogeneous and mainly chosen based on precise tumour staging. Unfortunately, clinical outcome has not changed significantly in over 30 years and tumour grade is still the best prognosticator of metastatic disease and survival. An option to improve this scenario is to identify molecular biomarkers in the early stage of the disease, or even before the disease onset. Blood-based liquid biopsies are a promising, non-invasive way to achieve this goal and there are an increasing number of studies which investigate their potential application in bone cancer diagnosis, prognosis and personalised therapy. This review summarises the interplay between clinical and molecular aspects of the three main bone sarcomas, alongside biomarker discovery and promising applications of liquid biopsy in each tumour context.

Analysis of a Preliminary microRNA Expression Signature in a Human Telangiectatic Osteogenic Sarcoma Cancer Cell Line

Telangiectatic osteosarcoma (TOS) is an aggressive variant of osteosarcoma (OS) with distinctive radiographic, gross, microscopic features, and prognostic implications. Despite several studies on OS, we are still far from understanding the molecular mechanisms of TOS. In recent years, many studies have demonstrated not only that microRNAs (miRNAs) are involved in OS tumorigenesis, development, and metastasis, but also that the presence in high-grade types of OS of cancer stem cells (CSCs) plays an important role in tumor progression. Despite these findings, nothing has been described previously about the expression of miRNAs and the presence of CSCs in human TOS. Therefore, we have isolated/characterized a putative CSC cell line from human TOS (TOS-CSCs) and evaluated the expression levels of several miRNAs in TOS-CSCs using real-time quantitative assays. We show, for the first time, the existence of CSCs in human TOS, highlighting the in vitro establishment of this unique stabilized cell line and an identification of a preliminary expression of the miRNA profile, characteristic of TOS-CSCs. These findings represent an important step in the study of the biology of one of the most aggressive variants of OS and the role of miRNAs in TOS-CSC behavior.

MicroRNA-615 functions as a tumor suppressor in osteosarcoma through the suppression of HK2

At present, the regulatory mechanisms of various microRNAs (miRNAs/miRs) have been elucidated in human cancers including osteosarcoma (OS). This study mainly focused on the role of miR-615 in OS, which has not yet been reported. Ninety-two OS tissues and normal samples were used in this study. Human osteoblast hFOB1.19 cells and OS cell line HOS were utilized to detect the expression of miR-615. The expression of miR-615 and gene expression were assessed by RT-qPCR and western blot analysis. Transwell, MTT and luciferase reporter assays were used to investigate the regulatory mechanism of miR-615 in OS. The results revealed that miR-615 expression was reduced in OS tissues and cells, and was associated with poor clinical outcomes and prognosis in OS patients. In addition, overexpression of miR-615 restrained cell viability and metastasis in OS. Furthermore, hexokinase 2 (HK2) was confirmed as a direct target of miR-615. Upregulation of HK2 was detected in OS tissues. The upregulation of HK2 weakened the tumor-suppressive effect of miR-615 in OS. Moreover, miR-615 blocked epithelial-mesenchymal transition (EMT) and inactivated the PI3K/AKT pathway in OS. To conclude, miR-615 acts as a tumor suppressor in OS, thus miR-615 can be used as a target for OS treatment.

The suppressive role of miR-362-3p in epithelial ovarian cancer

Ovarian cancer is a common cancer worldwide. Epithelial ovarian cancer (EOC) is the most common subtype of ovarian cancer. This study was designed to explore the function of miR-362-3p in EOC. QRT-PCR analysis was used to test miR-362-3p levels in EOC tissues and cell lines. Cell viability was tested via MTT assay. Transwell systems were applied to assay cell migration. The target gene of miR-362-3p was evaluated using dual luciferase reporter assays. The MyD88 protein in EOC cells was tested via western blot. Our data showed that miR-362-3p was expressed at low levels in EOC tissues and cells. miR-362-3p inhibited cell proliferation and migration, bound the 3′-untranslated region (UTR) of MyD88, and inhibited MyD88 expression. MyD88 was inversely correlated with miR-362-3p in EOC, and MyD88 overexpression partly reduced the anti-proliferative effect of miR-362-3p in EOC cells. In conclusion, our data showed that miR-362-3p has an anti-proliferative effect on EOC.

Role of cancer stem cells in the development of giant cell tumor of bone

The primary bone tumor is usually observed in adolescence age group which has been shown to be part of nearly 20% of the sarcomas known today. Giant cell tumor of bone (GCTB) can be benign as well as malignant tumor which exhibits localized dynamism and is usually associated with the end point of a long bone. Giant cell tumor (GCT) involves mononuclear stromal cells which proliferate at a high rate, multinucleated giant cells and stromal cells are equally present in this type of tumor. Cancer stem cells (CSCs) have been confirmed to play a potential role in the development of GCT. Cancer stem cell-based microRNAs have been shown to contribute to a greater extent in giant cell tumor of bone. CSCs and microRNAs present in the tumors specifically are a great concern today which need in-depth knowledge as well as advanced techniques to treat the bone cancer effectively. In this review, we attempted to summarize the role played by cancer stem cells involving certain important molecules/factors such as; Mesenchymal Stem Cells (MSCs), miRNAs and signaling mechanism such as; mTOR/PI3K-AKT, towards the formation of giant cell tumor of bone, in order to get an insight regarding various effective strategies and research advancements to obtain adequate knowledge related to CSCs which may help to focus on highly effective treatment procedures for bone tumors.

Advances in Sensing Technologies for Monitoring of Bone Health

: Changing lifestyle and food habits are responsible for health problems, especially those related to bone in an aging population. Poor bone health has now become a serious matter of concern for many of us. In order to avoid serious consequences, the early prediction of symptoms and diagnosis of bone diseases have become the need of the hour. From this inspiration, the evolution of different bone health monitoring techniques and measurement methods practiced by researchers and healthcare companies has been discussed. This paper focuses on various types of bone diseases along with the modeling and remodeling phenomena of bones. The evolution of various diagnosis tests for bone health monitoring has been also discussed. Various types of bone turnover markers, their assessment techniques, and recent developments for the monitoring of biochemical markers to diagnose the bone conditions are highlighted. Then, the paper focuses on the potential assessment of the recent sensing techniques (physical sensors and biosensors) that are currently available for bone health monitoring. Considering the importance of electrochemical biosensors in terms of high sensitivity and reliability, specific attention has been given to the recent development of electrochemical biosensors and significance in real-time monitoring of bone health.

LncRNA OR3A4 Regulated the Growth of Osteosarcoma Cells by Modulating the miR-1207-5p/G6PD Signaling

Background

Increasing evidence has demonstrated the importance of non-coding RNAs including long non-coding RNA (lncRNA) and microRNAs (miRNAs) in the tumorigenesis of osteosarcoma (OS). Abnormal expression of lncRNA olfactory receptor family 3 subfamily A member 4 (OR3A4) was found in multiple human cancers; however, the function of OR3A4 in OS remains largely unknown.

Materials and Methods

The expression level of OR3A4 in OS tissues and cell lines was detected by RT-qPCR. Cell counting kit-8 assay, colony formation and flow cytometry analysis were performed to determine the growth of OS cells. The targets of OR3A4 were predicted using the miRDB database. The binding between OR3A4 and miRNAs was confirmed by dual-luciferase reporter assay.

Results

OR3A4 was overexpressed in OS tissues and correlated with the advanced progression of OS patients. Down-regulation of OR3A4 significantly inhibited the proliferation and colony formation of OS cells. Mechanistically, OR3A4 acted as a sponge of miR-1207-5p. Glucose-6-phosphate dehydrogenase (G6PD) was identified as a target of miR-1207-5p. Knockdown of OR3A4 increased the expression of miR-1207-5p and consequently, suppressed the level of G6PD in OS cells. Due to the essential role of G6PD in the pentose phosphate pathway (PPP), depletion of OR3A4 inhibited NADPH production, glucose consumption and lactate generation. Decreased level of NADPH by depletion of OR3A4 up-regulated the redox state (ROS) content and resulted in endoplasmic reticulum (ER) stress in OS cells. Restoration of G6PD significantly attenuated the cell growth inhibition induced by OR3A4 knockdown.

Conclusion

Our finding suggested the critical role of OR3A4 in the proliferation of OS cells via targeting the miR-1207-5p/G6PD axis.

Up-Regulation of Hsa_circ_0008792 Inhibits Osteosarcoma Cell Invasion and Migration and Promotes Apoptosis by Regulating Hsa-miR-711/ZFP1

Objective

Circular RNA is a newly discovered non-coding RNA. It plays an important role in regulating gene expression, and may take part in tumor progression. This study aimed to investigate the functions of hsa_circ_0008792 in osteosarcoma regulation.

Methods

We identified a circular RNA, hsa_circ_0008792, by using bioinformatics to analyze the GSE96962 dataset. The capacities of migration and invasion were assessed by wound-healing assay and transwell Matrigel assay. The ratios of G0/G1, S, and G2/M phases in cell cycle and apoptosis were measured using flow cytometry.

Results

Hsa_circ_0008792 is expressed at low levels in osteosarcoma cells, and up-regulation of hsa_circ_0008792 could suppress osteosarcoma cell migration and invasion and promote apoptosis. This regulation is mediated by hsa-miR-711/ZFP1. The expression level of hsa_circ_0008792 showed no influence on cell cycle of osteosarcoma cells.

Conclusion

Osteosarcoma is suppressed by hsa_circ_0008792/hsa-miR-711/ZFP1 axis.

Polyethylenimine-dextran-coated magnetic nanoparticles loaded with miR-302b suppress osteosarcoma in vitro and in vivo

Aim: We attempted to synthesize a magnetic gene carrier with poly(ethylenimine), dextran and iron oxide nanoparticles (PDIs) for miR-302b transfection in vitro and in vivo. Materials & methods: The nanoparticles were characterized for hydrodynamic properties, ζ potential and DNA-binding ability, evaluated by transmission electron microscopy. Cellular internalization, magnetofection efficiency and anti-osteosarcoma effects were investigated in osteosarcoma (OS) cells and OS-bearing nude mice. Results: PDIs were successfully prepared and showed mild cytotoxicity. A magnetic field efficiently enabled transport of PDI/pmiR302b to OS cells in OS-bearing nude mice, exerting the anti-osteosarcoma effect of miR-302b at the tumor site. The inhibitory effect of miR-302b on osteosarcoma-bearing nude mice may be attributed to regulation of the Hippo pathway through YOD1. Conclusion: Low-cytotoxic PDIs have potential applications as a magnetic transport carrier for future osteosarcoma treatment.

microRNA-329 reduces bone cancer pain through the LPAR1-dependent LPAR1/ERK signal transduction pathway in mice

Background:

Bone cancer pain (BCP) is a common symptom occurring among patients with cancer and has a detrimental effect on their quality of life. Growing evidence has implicated microRNA-329 (miR-329) in the progression of bone diseases. In the present study, we aimed to elucidate the potential effects of miR-329 on BCP in a BCP mouse model via binding to lysophosphatidic acid receptor 1 (LPAR1) through the LPAR1/extracellular signal-regulated kinase (ERK) signaling pathway.

Methods:

Initially, a BCP mouse model was established via injection of 4 × 10⁴ murine breast tumor (4T1 cell) cells (4 μl). The interaction between miR-329 and LPAR1 was identified using a bioinformatics website and dual luciferase reporter gene assay. The modeled mice were subsequently treated with miR-329 mimic, LPAR1 shRNA, or both, in order to examine the effect of miR-329 on the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) of mice, the expression of LPAR1/ERK signaling pathway-related genes.

Results:

The positive expression rate of LPAR1 protein and extent of ERK1/2 phosphorylation were increased in BCP mouse models. LPAR1 is a target gene of miR-329, which can inhibit the expression of LPAR1. In response to miR-329 overexpression and LPAR1 silencing, BCP mice showed increased PWT and PWL, along with decreased LPAR1 expression and ratio of p-ERK/ERK.

Conclusions:

Altogether, the results obtained indicated that miR-329 can potentially alleviate BCP in mice via the inhibition of LPAR1 and blockade of the LPAR1/ERK signaling pathway, highlighting that upregulation of miR-329 could serve as a therapeutic target for BCP treatment.

MicroRNA-1296-5p suppresses the proliferation, migration, and invasion of human osteosarcoma cells by targeting NOTCH2

Osteosarcoma (OS) is a highly aggressive bone tumor with a poor prognosis. MicroRNAs are revealed to exerts essential roles in the carcinogenesis and tumor invasion of OS. But, the function of miR-1296-5p and its related mechanism in OS progression have not yet been studied. This study discovered the levels of miR-1296-5p in OS and corresponding noncancerous tissues, and we demonstrated that miR-1296-5p level was markedly downregulated in tumor specimens as compared with nontumor tissues. In addition, we discovered that miR-1296-5p was also underexpressed in OS cells compared with the hFOB1.19 osteoblast cells. Interestingly, the reduced expression of miR-1296-5p was confirmed to associated with large tumor size, advanced tumor stages, and distance metastasis, respectively. Patients with OS low-expressing miR-1296-5p showed a prominent shorter survival. In addition, gain-of-function assays verified that miR-1296-5p overexpression remarkably repressed OS cell proliferation, migration, and invasion. Conversely, depletion of miR-1296-5p facilitated the growth and mobility of OS cells. Notably, miR-1296-5p inversely modulated notch receptor 2 (NOTCH2) in OS cells. The level of NOTCH2 messenger RNA was negatively correlated with miR-1296-5p level in OS samples. NOTCH2 knockdown markedly suppressed the abilities of MG-63 cell proliferation and mobility. More importantly, the restoration of NOTCH2 prominently rescued miR-1296-5p-induced tumor-suppressive effects on MG-63 cells. In conclusion, our study identified the reduced expression of miR-1296-5p, which contributed to OS progression. miR-1296-5p might be a promising prognostic marker and therapeutic target in OS.

MicroRNA-876-5p inhibits cell proliferation, migration and invasion by targeting c-Met in osteosarcoma

Recently, aberrant expression of miR‐876‐5p has been reported to participate in the progression of several human cancers. However, the expression and function of miR‐876‐5p in osteosarcoma (OS) are still unknown. Here, we found that the expression of miR‐876‐5p was significantly down‐regulated in OS tissues compared to para‐cancerous tissues. Clinical association analysis indicated that underexpression of miR‐876‐5p was positively correlated with advanced clinical stage and poor differentiation. More importantly, OS patients with low miR‐876‐5p level had a significant shorter overall survival compared to miR‐876‐5p high‐expressing patients. In addition, gain‐ and loss‐of‐function experiments demonstrated that miR‐876‐5p restoration suppressed whereas miR‐876‐5p knockdown promoted cell proliferation, migration and invasion in both U2OS and MG63 cells. In vivo studies revealed that miR‐876‐5p overexpression inhibited tumour growth of OS in mice. Mechanistically, miR‐876‐5p reduced c‐Met abundance in OS cells and inversely correlated c‐Met expression in OS tissues. Herein, c‐Met was recognized as a direct target of miR‐876‐5p using luciferase reporter assay. Notably, c‐Met restoration rescued miR‐876‐5p attenuated the proliferation, migration and invasion of OS cells. In conclusion, these findings indicate that miR‐876‐5p may be used as a potential therapeutic target and promising biomarker for the diagnosis and prognosis of OS.

MiR-125b suppresses the carcinogenesis of osteosarcoma cells via the MAPK-STAT3 pathway

The microRNA (miRNA) miR-125b is abnormally expressed in many different types of tumors, including osteosarcoma (OS). How aberrantly expressed miR-125b participates in regulating the initiation and progression of OS is still poorly understood. In the current study, we found that in OS, miR-125b can suppress the expression of MAP kinase kinase 7 (MKK7), which can dephosphorylate and inactivate signal transducer and activator of transcription 3 (STAT3). We also identified an elevated expression level of MKK7 in OS and an association between MKK7 expression and poor prognosis. Further, miR-125b inhibited OS cell proliferation and invasion by targeting and downregulating MKK7 in vitro and suppressed tumor formation in vivo. Moreover, using Western blot analysis, we preliminarily proved that the activation (phosphorylation) of STAT3 was regulated by MKK7 at the epigenetic level. MKK7 was overexpressed in OS and associated with poor clinical results. The miR-125b-MAPK-STAT3 axis may be one of the mechanisms of OS oncogenesis and a potential target for the treatment of OS.

Clinical significance and correlation of microRNA-21 expression and the neutrophil-lymphocyte ratio in patients with acute myocardial infarction

OBJECTIVES

To explore the clinical significance and correlation of microRNA-21 (miR-21) and the neutrophil-lymphocyte ratio (NLR) in patients with acute myocardial infarction (AMI).

METHODS

The observation group contained 184 patients, while the control group contained 150 patients. The expression of miR-21 in the serum of each group was detected by qRT-PCR.

RESULTS

A total of 184 patients and their family members were followed-up for 30 days, among which 35 patients died and 149 patients survived, resulting in a survival rate of 80.97%. According to univariate analysis, there were significant differences in age, cardiac troponin (cTn), heart rate, Killip grade, percutaneous coronary intervention (PCI) operation rate, miR-21 and NLR. In the receiver operating characteristic (ROC) analysis, the area under the curve (AUC) values of miR-21 and NLR for the diagnosis of AMI were 0.909 and 0.868, respectively, and the area under the combined detection curve was 0.960. In the Kaplan-Meier survival analysis, the survival of patients with high miR-21 expression and NLR was significantly higher than that of patients with low miR-21 expression and NLR (p=0.027; p=0.001). The correlation showed that miR-21 expression in serum was positively correlated with the NLR in the observation group (r=0.528, p<0.05). cTn, heart rate, Killip classification, PCI operation rate, miR-21, NLR are independent risk factors for AMI.

CONCLUSION

miR-21 and NLR play a role in the diagnosis of AMI and can be used as predictors for the survival of AMI.

MicroRNA-466 inhibits osteosarcoma cell proliferation and induces apoptosis by targeting CCND1

Emerging pieces of evidence indicate that microRNA-466 (miR-466) serves as a tumor suppressor in several human tumors, including colorectal cancer and prostate cancer. However, whether miR-466 is involved in osteosarcoma (OS) progression remains largely unknown. The present study demonstrated that miR-466 was significantly downregulated in OS tissues and cell lines. Furthermore, it was revealed that the expression of miR-466 was negatively correlated with OS severity. Moreover, low miR-466 expression in patients with OS predicted poor prognosis. Through functional experiments, miR-466 overexpression significantly inhibited the proliferation and cell cycle of OS cells while inducing cellular apoptosis. In terms of mechanism, it was revealed that CCND1 was a target of miR-466 in OS cells. miR-466 overexpression suppressed CCND1 expression in OS cells. A reverse association was observed between the expression levels of miR-466 and CCND1 in OS tissues. Furthermore, CCND1 restoration in OS cells significantly rescued the effects of miR-466 on cellular proliferation and apoptosis. Overall, the results of the present study demonstrated that miR-466 suppressed OS progression by targeting CCND1, suggesting that miR-466 may be a promising biomarker and therapeutic target for OS prognosis and treatment.

The tumor suppressor role of microRNA-338-3p in renal cell carcinoma

Human renal cell carcinoma (RCC) is the most common type of kidney malignancy in adults accounting for 2-3% of all adult malignancies. In China, RCC accounts for ~0.5% of all cancer-associated mortalities, ranking 16th among all cancer types. For early-stage RCC, surgery is the recommended treatment. Molecularly targeted therapy is the preferred first-line treatment for clear-cell RCC. However, more potential targets are required. MicroRNA-338-3p (miR-338-3p) functions as a tumor suppressor in various cancers, but has not been studied in RCC. Accordingly, the present study investigated the role of miR-338-3p of RCC. It was demonstrated that miR-338-3p was present at low levels in RCC tissues. Also, overexpression of miR-338-3p inhibited cell proliferation and promoted cell apoptosis, and downregulation of miR-338-3p promoted cell proliferation. The 3' untranslated region of AKT serine/threonine kinase 3 was targeted by miR-338-3p. In conclusion, the data of the present study revealed the inhibitory function of miR-338-3p in RCC and suggested that miR-338-3p is novel therapeutic target for RCC, but further investigation is needed.

Inhibition of LCMR1 and ATG12 by demethylation-activated miR-570-3p is involved in the anti-metastasis effects of metformin on human osteosarcoma

Epidemiological studies have demonstrated that metformin could mitigate the progression of several tumors. Although it has been proved that metformin could cause demethylation of DNA and lead to up-regulation of some encoding genes and non-coding RNAs, there is little data about the effects of metformin on metastasis, and the interaction between metastasis and autophagy in human osteosarcoma cells. Here, we found miR-570-3p was significantly down-regulated in human metastatic osteosarcoma tissues but not in non-metastatic osteosarcoma tissues. Metformin attenuates the metastasis and autophagy in osteosarcoma. Interestingly, this autophagy favors osteosarcoma cells invasion. Moreover, reduction of metformin-induced inhibition of autophagy could reverse the invasion suppression in osteosarcoma. Mechanistically, metformin increases miR-570-3p by the demethylation of DNA, and the upregulation of miR-570-3p repressed the translation of its target, LCMR1 and ATG12. Our results, for the first time, presents evidence that the miR-570-3p-mediated suppression of LCMR1 and ATG12 is involved in the metformin-induced inhibition of metastasis in osteosarcoma cells.

Baicalein inhibits osteosarcoma cell proliferation and invasion through the miR‑183/Ezrin pathway

Osteosarcoma (OS), a common and primary malignant bone tumor, is characterized by highly aggressive potency. Baicalein, a bioactive flavone isolated from Scutellaria baicalensis Georgi, has been shown to inhibit the progression of numerous tumors, including OS. However, the mechanisms by which baicalein protects against OS are still largely unknown. The results of the present study showed that administration of baicalein significantly inhibited the proliferation, migration and invasion and promoted apoptosis in MG‑63 and Saos‑2 cells. Ezrin was identified as a target gene of microRNA (miR)‑183. MG‑63 and Saos‑2 cells treated with baicalein exhibited increased miR‑183 levels and decreased Ezrin expression. Importantly, miR‑183 inhibition and Ezrin overexpression abolished the effects of baicalein on MG‑63 and Saos‑2 cell proliferation, migration, invasion and apoptosis. Taken together, these findings suggest that baicalein inhibits the proliferation, migration and invasion and induces apoptosis in OS cells by activating the miR‑183/Ezrin pathway, revealing a novel mechanism underlying anti‑OS effects of baicalein.

MiRNA-543 promotes osteosarcoma cell proliferation and glycolysis by partially suppressing PRMT9 and stabilizing HIF-1α protein

Osteosarcoma (OS) is the most common primary bone tumor, occurring frequently in adolescents and possessing a high malignant severity. MicroRNAs play critical roles during OS development. Thus, elucidation of the involvement of specific microRNAs in the development of OS may provide novel therapeutic targets for OS treatment. Here, we showed that in the OS specimens from patients, the levels of miR-543 were significantly increased whereas the levels of PRMT9 were significantly decreased, compared to the paired normal bone tissue. Moreover, miR-543 and PRMT9 inversely correlated in the OS cell lines. Bioinformatics analyses predicted that miR-543 may target the 3'-UTR of PRMT9 mRNA to inhibit its translation, which was confirmed by luciferase-reporter assay. MiR-543 promoted OS cell proliferation in vitro and in vivo. Mechanistically, miR-543 inhibited PRMT9-enhanced cell oxidative phosphorylation, while miR-543 depletion promoted PRMT9-increased HIF-1α instability and inhibited glycolysis in OS cells. Clinically, miR-543 expression was negatively correlated with PRMT9 expression in OS tissues. Together, our data provide important evidence for glycolysis in OS development, and suggest that targeting glycolytic pathway through miR-543/PRMT9/HIF-1α axis may represent a potential therapeutic strategy to eradicate OS cells.

miR-365 functions as a tumor suppressor by directly targeting CYR61 in osteosarcoma

Increasing evidence indicates that microRNAs(miRNAs) are often aberrantly expressed in osteosarcoma (OS) and play critical roles in OS tumorigenesis. Therefore, the discovery of miRNAs may provide a new and powerful tool for understanding the mechanismof OS initiation and development. The aim of this study was to investigate the functional significance of miR-365 and identify its possible mechanism in OS cells. Here, wefound that the expression level of miR-365 is significantly downregulated in OS tissues and cell lines, and its expression isassociated with the clinical stage, distant metastasis, tumor grade, and poor overall survival rate. The overexpression of miR-365 is able to inhibit cell proliferation, migration, and invasion in Saos-2 and MG-63 cells. Moreover, the cysteine-rich angiogenic inducer 61 (CYR61) has been identified as a target of miR-365 in OS cells, and its expression is found to be significantly increased in OS tissues, which is negatively correlated with miR-365. Furthermore, CYR61 overexpression significantly attenuated the suppressive effects of miR-365 on the proliferation, migration, and invasion of Saos-2 and MG-63 cells. Therefore, we consider that miR-365 acts as a tumor suppressor in OS, partly, by targeting CYR61 expression.

MicroRNA-505 is downregulated in human osteosarcoma and regulates cell proliferation, migration and invasion

Recent studies have demonstrated that microRNAs (miRNAs/miRs) are involved in osteosarcoma tumorigenesis, progression, invasion and metastasis. For example, miR-505 plays important roles in human carcinogenesis; however, its exact function in osteosarcoma remains unclear. MicroRNA profiles of osteosarcoma and normal tissues were obtained by miRNA microarray assays, which were validated by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Then, high-mobility group box 1 (HMGB1) expression was evaluated by qRT-PCR and western blot analysis. The correlation between miR-505 and HMGB1 was analyzed by Pearson correlation. In vitro, the biological functions of miR-505 were examined by wound healing, MTT and Transwell assays and western blot analysis in MG63 cells transfected with miRNA mimics or empty vector. Luciferase assay was utilized to assess whether HMGB1 is a target of miR-505. miRNA microarrays revealed 26 aberrant miRNAs in osteosarcoma tissues; miR-505 showed the most pronounced decrease (P<0.01), which was significantly associated with TNM stage and metastasis status (P<0.05). In addition, HMGB1 was highly expressed in osteosarcoma tissues (P<0.01), with a significantly negative correlation with miR-505 (r=−0.6679, P<0.001). Furthermore, miR-505 inhibited proliferation, migration and invasion abilities of MG63 cells (P<0.01). Moreover, luciferase activity of the HMGB1-3′-UTR plasmid was suppressed following miR-505 binding (P<0.01). Finally, HMGB1 overexpression partly reversed the effects of miR-505 on MG63 cells. In conclusion, miR-505 levels are decreased in osteosarcoma tissues, and reduced miR-505 expression is significantly associated with poorer clinical prognosis in patients with osteosarcomas. miR-505 inhibits osteosarcoma cell proliferation, migration and invasion by regulating HMGB1.

Small non-coding RNAs-based bone regulation and targeting therapeutic strategies

Small non-coding RNAs, which are 20-25 nucleotide ribonucleic acids, have emerged as an important transformation in the biological evolution over almost three decades. microRNAs (miRNAs) and short interfering RNAs (siRNAs) are two significant categories of the small RNAs that exert important effects on bone endocrinology and skeletology. Therefore, clarifying the expression and function of these important molecules in bone endocrine physiology and pathology is of great significance for improving their potential therapeutic value for metabolism-associated bone diseases. In the present review, we highlight the recent advances made in understanding the function and molecular mechanism of these small non-coding RNAs in bone metabolism, especially their potentially therapeutic values in bone-related diseases.

MicroRNA-27a functions as an oncogene in human osteosarcoma by targeting CCNG1

Osteosarcoma is the most common type of malignant tumor arising from bone in children and adolescents. Accumulating evidences have shown the aberrant expression of numerous miRNAs is associated with the development and metastasis of osteosarcoma. The present study was conducted to investigate miR-27a expression in osteosarcoma tissues and cells. In the present study, quantitative RT-qPCR was used to measure the expression levels of miRNA and mRNA in osteosarcoma tissues and cells. Transwell assays were used to detect the effects of miR-27a on the invasive and migratory potential of cells. Luciferase reporter and western blot analysis were conducted to confirm cyclin G1 (CCNG1) as the target gene of miR-27a. The results showed that miR-27a was significantly upregulated in human osteosarcoma tissues and cell lines. The western blot analysis revealed that the overexpression of miR-27a suppressed CCNG1 protein expression. Luciferase reporter assays confirmed that CCNG1 is a direct target of miR-27a in osteosarcoma cells. The results suggest that miR-27a downregulates CCNG1 expression in osteosarcoma and acts as an oncogene directly targeting CCNG1. Thus, the miR-27a/CCNGI axis is a potential therapeutic target for human osteosarcoma.

RETRACTED: miR-367 regulation of DOC-2/DAB2 interactive protein promotes proliferation, migration and invasion of osteosarcoma cells

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the authors, who have informed the Editor-in-Chief that miR-367 overexpression did not significantly reduce the DAB2IP level in MG-63 cells as shown in Figures 4C and 4D of the published article. Furthermore, the effects of miR-367 overexpression and DAB2IP knockdown on the proliferation and metastasis of MG-63 cells in Figure 2 and Figure 6 are also no longer repeatable. Subsequent analysis showed that the MG-63 cells used in this study were contaminated with HeLa cells, identified by short tandem repeat analysis. The authors believe cell contamination may be the main reason why the reported results are not reproducible. The authors no longer have confidence in the reliability of the results and would like to apologize for any inconvenience caused. The Editor-in-Chief agreed to retract the article.

MicroRNAs and Fracture Healing

MicroRNAs (miRNAs) are small molecules found to have major regulatory roles in many biological processes. This review aims to provide an overview of the recent advances in knowledge of the role of miRNAs in fracture healing and bone repair. A search of the published literature was performed (using the PubMed database) to include all relevant studies published in English. These studies were then reviewed and the results condensed into this review paper. MiRNAs have now been shown to have significant alterations in expression levels in bone tissue in the presence of fractures. This is thought to be related to the process of fracture healing through effects on osteoblasts and bone growth factors. These small molecules are also detectable in the circulation where their expression appears to be altered by the presence of fractures. Although further research is required in this area, miRNAs may present an opportunity for future clinical applications in fracture management.

Sphingosine-1-phosphate suppresses chondrosarcoma metastasis by upregulation of tissue inhibitor of metalloproteinase 3 through suppressing miR-101 expression

Chondrosarcoma is the second most common primary malignancy form of bone cancer, exhibiting resistance to chemotherapy and radiation therapy as well as developing high metastasis ability in late‐stage tumors. Thus, understanding the metastatic processes of chondrosarcoma is considered a strategy for the treatment of this disease. Sphingosine 1‐phosphate (S1P), a bioactive sphingolipid, is produced intracellularly by sphingosine kinase (SphK) and is regarded as a second signaling molecule that regulates inflammation, proliferation, angiogenesis, and metastasis. However, the effect of S1P on chondrosarcoma remains uncertain. As demonstrated by the transwell, immunoblotting, and real‐time PCR analyses, we found that S1P inhibited cell migration and MMP‐2 expression through the upregulation of the tissue inhibitor of metalloproteinase‐3 (TIMP‐3) expression in human chondrosarcoma cells. Additionally, we also showed that microRNA (miRNA)‐101, which targets the 3′ untranslated region (3′UTR) of TIMP‐3, decreased significantly following S1P treatment. After transfection with miR‐101 mimics, the S1P‐regulated cell migration and TIMP‐3 expression were both reversed. Furthermore, we also showed that the S1P‐inhibited cell migration is mediated through the c‐Src/MEK/ERK signaling axis. Meanwhile, the in vivo study indicated that overexpression of SphK1 decreases chondrosarcoma metastasis to the lungs. Our results illustrate the clinical significance between SphK1, TIMP‐3, and miR‐101 in human chondrosarcoma patients. Taken together, our results suggest that S1P and miR‐101 may prove to be potential therapeutic targets for future chondrosarcoma treatment.

MicroRNA-25 suppresses proliferation, migration, and invasion of osteosarcoma by targeting SOX4

Altered expression of the miR-25 has been implicated in many human malignant progression as oncogene or tumor suppressor. However, the precise role of miR-25 in osteosarcoma progression remains largely unclear. This study aimed to investigate the role and underlying mechanism of miR-25 in osteosarcoma. In this study, we demonstrated that miR-25 was significantly downregulated in osteosarcoma cell lines and tissues and that lower miR-25 was associated with advanced tumor-node-metastasis stage and lymph node metastasis. Then, we found that introduction of miR-25 significantly suppressed the proliferation, colony formation, migration, and invasion of osteosarcoma cells in vitro and retarded tumor growth in vivo. Further studies indicated that the epithelial-mesenchymal transition-related transcription factor, SOX4 (SRY-related high-mobility group box 4), was a direct target gene of miR-25, evidenced by bioinformatics analysis predicted and luciferase reporter assay. Furthermore, miR-25 could decrease the expression of SOX4 levels and inhibited epithelial-mesenchymal transition process. The levels of miR-25 were inversely correlated with those of SOX4 expression in osteosarcoma tissues. SOX4 overexpression rescued miR-25-induced suppression of proliferation, migration, and invasion of osteosarcoma cells. Taken together, these results suggest that miR-25 functions as a tumor suppressor in the progression of osteosarcoma by repressing SOX4.

Gankyrin as a potential therapeutic target for cancer

Gankyrin is an oncoprotein that plays a central role in the development of cancer. Although researchers have increasingly focused on the relationships of gankyrin with carcinogenesis, metastasis and prognosis of different cancers, the molecular mechanisms are still unclear. In recent years, several interacting partners of gankyrin and cell signaling pathways regulated by gankyrin have been elucidated. In addition, accumulating evidence has indicated the contribution of microRNAs to regulating gankyrin expression in tumor cells. In this review, we summarize the major known roles of gankyrin in cancer cells and highlight the potential clinical relevance of targeting gankyrin. Graphical abstract ᅟ.

MicroRNAs in bone diseases

MicroRNAs are small, noncoding single-stranded RNAs that have emerged as important posttranscriptional regulators of gene expression, with an essential role in vertebrate development and different biological processes. This review highlights the recent advances in the function of miRNAs and their roles in bone remodeling and bone diseases. MicroRNAs (miRNAs) are a class of small (∼22 nt), noncoding single-stranded RNAs that have emerged as important posttranscriptional regulators of gene expression. They are essential for vertebrate development and play critical roles in different biological processes related to cell differentiation, activity, metabolism, and apoptosis. A rising number of experimental reports now indicate that miRNAs contribute to every step of osteogenesis and bone homeostasis, from embryonic skeletal development to maintenance of adult bone tissue, by regulating the growth, differentiation, and activity of different cell systems inside and outside the skeleton. Importantly, emerging information from animal studies suggests that targeting miRNAs might become an attractive and new therapeutic approach for osteoporosis or other skeletal diseases, even though there are still major concerns related to potential off target effects and the need of efficient delivery methods in vivo. Moreover, besides their recognized effects at the cellular level, evidence is also gathering that miRNAs are excreted and can circulate in the blood or other body fluids with potential paracrine or endocrine functions. Thus, they could represent suitable candidates for becoming sensitive disease biomarkers in different pathologic conditions, including skeletal disorders. Despite these promising perspectives more work remains to be done until miRNAs can serve as robust therapeutic targets or established diagnostic tools for precision medicine in skeletal disorders.

miR-214-5p Targets ROCK1 and Suppresses Proliferation and Invasion of Human Osteosarcoma Cells

MicroRNAs (miRNAs) are small conserved RNAs regulating specific target genes in posttranscriptional levels. They have been involved in multiple processes of tumor progression, including cell proliferation. miR-214-5p (also miR-214*) is a newly identified miRNA, and its functions are largely unknown. In this study, we explore the role of miR-214-5p in the proliferation and invasion of human osteosarcoma (OS) cells. The results showed that miR-214-5p was sharply reduced in OS tissues and cell lines, compared with normal tissues and cell lines. In addition, the miR-214-5p mimic greatly increased the miR-214-5p level and significantly decreased the proliferation and invasion of HOS and G293 OS cells. In contrast, the miR-214-5p inhibitor had a completely opposite effect on the miR-214-5p level, cell proliferation, and cell invasion. Moreover, bioinformatics and luciferase reporter gene assays confirmed that miR-1908 targeted the mRNA 3'-UTR region of ROCK1, a characterized tumor promoter in OS. In conclusion, miR-214-5p was identified as a new tumor suppressor, which directly targeted ROCK1 and suppressed proliferation of human OS cells.

What Is New in the miRNA World Regarding Osteosarcoma and Chondrosarcoma?

Despite the availability of multimodal and aggressive therapies, currently patients with skeletal sarcomas, including osteosarcoma and chondrosarcoma, often have a poor prognosis. In recent decades, advances in sequencing technology have revealed the presence of RNAs without coding potential known as non-coding RNAs (ncRNAs), which provides evidence that protein-coding genes account for only a small percentage of the entire genome. This has suggested the influence of ncRNAs during development, apoptosis and cell proliferation. The discovery of microRNAs (miRNAs) in 1993 underscored the importance of these molecules in pathological diseases such as cancer. Increasing interest in this field has allowed researchers to study the role of miRNAs in cancer progression. Regarding skeletal sarcomas, the research surrounding which miRNAs are involved in the tumourigenesis of osteosarcoma and chondrosarcoma has rapidly gained traction, including the identification of which miRNAs act as tumour suppressors and which act as oncogenes. In this review, we will summarize what is new regarding the roles of miRNAs in chondrosarcoma as well as the latest discoveries of identified miRNAs in osteosarcoma.

MicroRNA-467g inhibits new bone regeneration by targeting Ihh/Runx-2 signaling

MicroRNAs are important post transcriptional regulators of gene expression and play critical role in osteoblast differentiation. In this study we report miR-467g, an uncharacterized novel miRNA, in regulation of osteoblast functions. Over-expression of miR-467g inhibited osteoblast differentiation. Target prediction analysis tools and experimental validation by luciferase 3' UTR reporter assay identified Runx-2 as a direct target of miR-467g. Over expression of miR-467g in osteoblasts down regulated Runx-2 and Ihh signaling components. Furthermore, silencing of miR-467g was done to see its role in Ihh and Runx-2 mediated bone healing and regeneration in a drill hole injury model in BALB/c mice. Silencing of miR-467g led to significant increase in new bone regeneration and Ihh and Runx-2 localization at injury site in a day dependent manner. In conclusion, miR-467g negatively regulates osteogenesis by targeting Ihh/Runx-2 signaling. We, thus, propose that therapeutic approaches targeting miR-467g could be useful in enhancing the new bone formation.

Overexpression of miR-92a promotes the tumor growth of osteosarcoma by suppressing F-box and WD repeat-containing protein 7

MicroRNAs (miRNAs) have been reported to be critical players in osteosarcoma (OS). Among numerous cancer-related miRNAs, the expression level of miR-92a and its potential role in OS has not been investigated. Here, We showed that overexpression of miR-92a was identified in OS specimens and cells compared to normal bone tissues. The high level of miR-92a was correlated with high T classification and advanced clinical stages of OS patients. Notably, miR-92a highly expressing OS patients showed a notably reduced survival rate. In vitro experiments showed that loss of miR-92a inhibited U2OS cell proliferation and cell-cycle progression while induced apoptosis. In turn, its restoration facilitated MG-63 cell growth and suppressed apoptosis. Experimental nude mice showed that miR-92a silencing prohibited the in vivo growth of OS cells. Furthermore, bioinformatics software predicted that F-box and WD repeat-containing protein 7 (FBXW7) was a direct target of miR-92a. We then observed the negative regulation of miR-92a on FBXW7 expression and the direct binding between them was further verified by dual-luciferase assays in OS cells. Forced expression of FBXW7 resulted in reduced proliferation, cell cycle arrest at G1 phase and increased apoptosis in miR-92a overexpressing MG-63 cells. In summary, this study demonstrates miR-92a probably functions as a driver of tumor progression by targeting FBXW7, and highlights the potential effects of miR-92a on prognosis and treatment of OS.

Induction of the mesenchymal to epithelial transition by demethylation-activated microRNA-125b is involved in the anti-migration/invasion effects of arsenic trioxide on human chondrosarcoma

Background

In addition to treating acute promyelocytic leukemia, arsenic trioxide (ATO) suppresses other solid tumors, including chondrosarcoma. However, the effects of ATO on metastasis in chondrosarcoma cells, and the underlying molecular mechanisms remain unclear.

Methods

The effects of ATO on the migratory and invasive capacities of chondrosarcoma cells were investigated by Wound healing, Transwell and EMT assays. The expression of miR-125b in human chondrosarcoma tissues and cell lines was detected by real-time PCR analysis. Bisulfite sequencing analysis (BSP) was used to detect the effects of ATO on the expression of miR-125b. The gain-of-function and loss-of-function experiments were performed on chondrosarcoma cell lines to investigate the effects of miR-125b on chondrosarcoma invasion, and to determine whether signal transducer and activator of transcription 3(Stat3) mediates these effects. Dual-luciferase reporter assay was used to identify whether Stat3 is a direct target of miR-125b.

Results

MiR-125b was significantly downregulated in human metastatic chondrosarcoma tissues and cell lines but not in non-metastatic chondrosarcoma tissues. ATO up-regulates the expression of miR-125b by the demethylation of DNA. ATO induces MET and attenuates the invasive capacities of chondrosarcoma cells through miR-125b. Stat3 was verified as a direct target of miR-125b, which is involved in ATO regulating EMT-associated traits.

Conclusions

These findings, for the first time, provides evidence that the miR-125b-mediated inhibition of Stat3 is involved in the ATO-induced attenuation of metastasis in chondrosarcoma cells.

MicroRNA biogenesis and their functions in regulating stem cell potency and differentiation

Stem cells are unspecialized/undifferentiated cells that exist in embryos and adult tissues or can be converted from somatic differentiated cells. Use of stem cells for tissue regeneration and tissue engineering has been a cornerstone of the regenerative medicine. Stem cells are also believed to exist in cancer tissues, namely cancer stem cells (CSCs). Growing evidence suggests that CSCs are the culprit of cancer dormancy, progression and recurrence, and thus have recently received great attention. MicroRNAs (miRNAs) are a group of short, non-coding RNAs that regulate expression of a wide range of genes at a post-transcriptional manner. They are emerging as key regulators of stem cell behaviors. This mini review summarizes the basic biogenesis and mode of actions of miRNAs, recent progress and discoveries of miRNAs in cellular reprogramming, stem cell differentiation and cellular communication, as well as miRNAs in CSCs. Some potential of miRNAs in future biomedical applications and research pertaining to stem cells are briefly discussed.