Dissecting the functional role of microRNA 21 in osteosarcoma

Research progress on the role of lncRNA, circular RNA, and microRNA networks in regulating ferroptosis in osteosarcoma

Noncoding RNAs (ncRNAs) do not participate in protein-coding. Ferroptosis is a newly discovered form of cell death mediated by reactive oxygen species and lipid peroxidation. Recent studies have shown that ncRNAs such as microRNAs, long noncoding RNAs, circular RNAs, and ferroptosis are involved in the occurrence and development of osteosarcoma (OS). Studies have confirmed that ncRNAs participate in the development of OS by regulating the ferroptosis. However, systematic summary on this topic are still lacking. This review summarises the potential role of ncRNAs in the diagnosis, treatment, drug resistance, and prognosis of OS and the basis for diagnosing, preventing, and treating clinical OS and developing effective drugs. This review summarises the latest research progress on ncRNAs that regulate ferroptosis in OS, attempts to clarify the molecular mechanisms by which ncRNAs regulate ferroptosis in the pathogenesis of OS, and elaborates on the involvement of ferroptosis in OS from the perspective of ncRNAs.

Osteosarcoma in a ceRNET perspective

Osteosarcoma (OS) is the most prevalent and fatal type of bone tumor. It is characterized by great heterogeneity of genomic aberrations, mutated genes, and cell types contribution, making therapy and patients management particularly challenging. A unifying picture of molecular mechanisms underlying the disease could help to transform those challenges into opportunities.This review deeply explores the occurrence in OS of large-scale RNA regulatory networks, denominated "competing endogenous RNA network" (ceRNET), wherein different RNA biotypes, such as long non-coding RNAs, circular RNAs and mRNAs can functionally interact each other by competitively binding to shared microRNAs. Here, we discuss how the unbalancing of any network component can derail the entire circuit, driving OS onset and progression by impacting on cell proliferation, migration, invasion, tumor growth and metastasis, and even chemotherapeutic resistance, as distilled from many studies. Intriguingly, the aberrant expression of the networks components in OS cells can be triggered also by the surroundings, through cytokines and vesicles, with their bioactive cargo of proteins and non-coding RNAs, highlighting the relevance of tumor microenvironment. A comprehensive picture of RNA regulatory networks underlying OS could pave the way for the development of innovative RNA-targeted and RNA-based therapies and new diagnostic tools, also in the perspective of precision oncology.

Circulating miRNA-21 is an innovative biomarker for cardiovascular events in erectile dysfunction patients

Introduction

It is well-known that circulating microRNAs (miRNAs) play a relevant role in many kinds of diseases by regulating the expression of genes involved in various pathophysiologic processes, including erectile dysfunction (ED) and cardiovascular diseases (CVD).

Purpose

This study aimed to identify the miRNA-21 profile in the blood samples of patients with ED, CVD, and the combination of both pathologies to elucidate the potential function of miRNA-21.

Methods

A total of 45 patients with CVD and/or who underwent the erectile function test were included and divided into the following categories: CVD with ED (cases, n = 29) and controls (n = 16) with either ED or CVD. Real-time polymerase chain reaction analysis verified the results. miRNA-21 expression was quantified, and informatics analysis was applied to predict the functions of this differentially expressed miRNA-21.

Results

A total of 64% of cases (63 ± 9 years, 66% with severe ED, 56% with CV ejection fraction) first presented ED as the sentinel clinical manifestation. Serum miRNA-21 levels in the control ED were significant, up to 10-fold higher than in the CVD controls and cases. A significant inverse (p = 0.0368, β = -2.046) correlation was found between erectile function and miRNA-21 levels.

Conclusions

Our study provides comprehensive insights into the functional interaction between miRNA-21 and ED in CVD patients. Its relevance lies in the potential of miRNA as a biomarker to be applied in the cardiovascular predictive medicine field.

Prevalence and Association between Primary Stability and Bone Quality in Implants Placed in Edentulous Dental Arches: A Retrospective Analysis

Immediate function has become an accepted treatment modality for fixed restorations in completely edentulous jaws. The dental implants have gained immense popularity. A secure implant primary stability is positively associated with a successful implant integration and long term successful clinical outcome. The main aim of this study was to find the association between primary stability and bone density in implants placed in maxilla and mandible. A total of 1263 patients who had undergone implant placement from March 2020-March 2021 in Saveetha Dental College and Hospitals, Chennai, India were chosen for the study. The primary stability and bone density of these patients were collected from the hospital records. The collected data was compiled, reviewed, tabulated in Microsoft Excel sheet and entered in SPSS software for statistical analysis. In the present study, the patient aged between 28 and 37 years had undergone more implant placement (31%) with male predilection (53%). The most commonly associated primary stability was found to be 30-40 Ncm (51.37%) predominantly with D2 type of bone density (52.69%). A Chi-squared statistical test was done for primary stability and bone density and the P was found to be 0.00 (Chi-squared P < 0.05, statistically significant). The most predominant bone density was D2 associated with primary stability of 30-40 Ncm. The association between bone density and primary stability was found to be statistically significant. The present study shows a strong relationship between bone density and primary implant stability.

Gender-based cytomorphometric analysis of buccal exfoliated cells in a South Indian population

OBJECTIVE

To assess differences based on gender in nuclear area (NA), cytoplasmic area (CA), and nuclear-cytoplasmic ratio (N:C ratio) values for clinically normal buccal smears in apparently healthy subjects of a South Indian population, thereby providing definitive baseline cytomorphometric measurements for the South Indian population.

METHODS

Buccal smears were collected from 60 healthy subjects (30 males and 30 females) of a South Indian population above 18 years in age. Values of the NA and CA were measured, and the N:C ratio calculated, using ImageJ software. Statistical analysis of the data with independent t tests and 95% confidence intervals was done using SPSS version 21 (significance set at P < 0.05).

RESULTS

The results showed that there were significant differences in the NA, CA, and N:C values between males and females irrespective of age (P = 0.01).

CONCLUSION

Definitive gender-specific baseline cytomorphometric data can be established using exfoliative cytology for the South Indian population, and this may be helpful in deciphering the occurrence of oral pre-malignant diseases and oral squamous cell carcinoma in this population, as the incidence of these conditions varies with gender and different ethnic groups.

LINC00943 regulates miR-1252-5p/YWHAH axis to promote tumor proliferation and metastasis in lung adenocarcinoma

Lung cancer is the most common malignant tumor worldwide. In recent years, the incidence of lung adenocarcinoma (LAD) has increased significantly, with an unfavorable 5-year survival rate. Long non-coding RNAs (lncRNAs) have been shown to play a significant role in the emergence, growth, and metastasis of tumors. However, the functional role and mechanism of LINC00943 in LAD progression have not yet been investigated. Aberrant expressions of LINC00943, miR-1252-5p, and YWHAH were determined by RT-qPCR and Western blot analyses. The binding relationship between miR-1252-5p and LINC00943 or YWHAH was examined by Pearson's correlation analysis, RNA pull-down, and dual-luciferase reporter assays. MTT assay was conducted to measure cell viability and colony formation assay was performed to evaluate cell proliferation potential. Transwell assay was used to investigate cell migration and invasion and flow cytometry was applied to evaluate cell apoptosis. We found that LINC00943 was highly expressed in LAD tissue samples and cell lines and was a reliable biomarker with high sensitivity, and specificity (P < 0.0001; AUC: 0.8966) for LAD detection. LINC00943 was mainly localized in the cytoplasm. In vitro, LINC00943 promoted LAD cell proliferation, migration, and invasion; however, silencing LINC00943 inhibited LAD tumor metastasis. Mechanistically, LINC00943 was competitively bound with miR-1252-5p to enhance YWHAH expression. Moreover, LINC00943 silencing sponged miR-1252-5p to inhibit YWHAH, thereby retraining LAD cell malignant behaviors. In summary, LINC00943 facilitates LAD cell malignancy through sponging miR-1252-5p to upregulate YWHAH. LINC00943 is a novel lncRNA that serves as an oncogene and might be used as a prognostic biomarker for LAD.

Modulation of immunosuppressive cells and noncoding RNAs as immunotherapy in osteosarcoma

The most common bone cancer is osteosarcoma (OS), which mostly affects children and teenagers. Early surgical resection combined with chemotherapy significantly improves the prognosis of patients with OS. Existing chemotherapies have poor efficacy in individuals with distant metastases or inoperable resection, and these patients may respond better to novel immunotherapies. Immune escape, which is mediated by immunosuppressive cells in the tumour microenvironment (TME), is a major cause of poor OS prognosis and a primary target of immunotherapy. Myeloid-derived suppressor cells, regulatory T cells, and tumour-associated macrophages are the main immunosuppressor cells, which can regulate tumorigenesis and growth on a variety of levels through the interaction in the TME. The proliferation, migration, invasion, and epithelial-mesenchymal transition of OS cells can all be impacted by the expression of non-coding RNAs (ncRNAs), which can also influence how immunosuppressive cells work and support immune suppression in TME. Interferon, checkpoint inhibitors, cancer vaccines, and engineered chimeric antigen receptor (CAR-T) T cells for OS have all been developed using information from studies on the metabolic properties of immunosuppressive cells in TME and ncRNAs in OS cells. This review summarizes the regulatory effect of ncRNAs on OS cells as well as the metabolic heterogeneity of immunosuppressive cells in the context of OS immunotherapies.

Split-DNAzyme cooperating primer exchange reaction for sensitive miRNA detection

Sensitive quantification of microRNA (miRNA) plays a crucial role in early diagnosis and precise therapy of osteosarcoma. Herein, we build a label-free and sensitive miRNA quantification approach based on the activation of split-DNAzyme initiated primer exchange reaction (PER). Target miRNA cooperates the activation of split-DNAzyme with Mg2+ through assisting the assembly of DNAzyme to correct conformation, which enables the performance of PER-based nucleic acids amplification to produce a large amount of single-strand DNA (ssDNA) sequences. The G-quadruplexes (G4) in ssDNA sequences products bind with N-methyl mesoporphyrin IX (NMM) to form G4-NMM complex with the enhanced fluorescence respond. The results demonstrate that miRNA-21 can assist the activation of split-DNAzyme, and the active DNAzyme exhibits a high specificity and efficiency in inducing the subsequent PER. Based on the split-DNAzyme-assisted signal recycle and PER, the method eventually shows a high sensitivity and selectivity, providing a promising prospect for the for early stage tumor diagnosis and more precise tumor therapy.

Comparison of Selected Non-Coding RNAs and Gene Expression Profiles between Common Osteosarcoma Cell Lines

Simple Summary

Osteosarcoma (OS) is a malignant tumour affecting mainly children and elderly people. Despite significant advances in cancer medicine, osteosarcoma patients’ survival is not improving. The primary treatment methods are established using in vitro models that rely upon the application of well-established cell lines, including U-2 OS, Saos-2 and MG-63. The molecular phenotype of these cell lines is still not fully outlined. Therefore, our study aimed to establish the expression profile of molecular markers related to osteosarcoma survival, progression and metastasis. Non-bone-related cells were used as a reference, i.e. HeLa cell line and human adipose-derived stromal cells (hASCs). Evaluated osteosarcoma cell lines showed characteristic phenotypes with unique patterns related to upregulation of MMP-7, MMP-14, BMP-7, miR-21-5p, miR-124-3p and downregulation of lncRNA MEG3. Our findings may facilitate the selection of the most reliable cellular model for pre-clinical investigations focused on developing new and satisfying methods of osteosarcoma therapy.

Abstract

Osteosarcoma (OS) is a bone tumour affecting adolescents and elderly people. Unfortunately, basic treatment methods are still underdeveloped, which has a high impact on the poor survivability of the patients. Studies designed to understand the underlying mechanisms of osteosarcoma development, as well as preclinical investigations aimed at establishing novel therapeutic strategies, rely significantly upon in vitro models, which apply well-established cell lines such as U-2 OS, Saos-2 and MG-63. In this study, the expression of chosen markers associated with tumour progression, metastasis and survival were identified using RT-qPCR. Levels of several onco-miRs (miR-21-5p, miR-124-3p, miR-223-3p and miR-320a-3p) and long non-coding RNA MEG3 were established. The mRNA expression of bone morphogenetic proteins (BMPs), including BMP-2, BMP-3, BMP-4, BMP-6, BMP-7, as well as their receptors: BMPR-IA, BMPR-IB and BMPR-II was also determined. Other tested markers included metalloproteinases, i.e., MMP-7 and MMP-14 and survivin (BIRC5), C-MYC, as well as CYCLIN D (CCND1). The analysis included comparing obtained profiles with transcript levels established for the osteogenic HeLa cell line and human adipose-derived stromal cells (hASCs). The tested OS cell lines were characterised by a cancer-related phenotype, such as increased expression of mRNA for BMP-7, as well as MMP-7 and MMP-14. Osteosarcoma cells differ considerably in miR-21-5p and miR-124-3p levels, which can be related to uncontrolled tumour growth. The comprehensive examination of osteosarcoma transcriptome profiles may facilitate the selection of appropriate cell models for preclinical investigations aimed at the development of new strategies for OS treatment.

Extracellular vesicles from bone mesenchymal stem cells transport microRNA-206 into osteosarcoma cells and target NRSN2 to block the ERK1/2-Bcl-xL signaling pathway

Osteosarcoma (OS) is a kind of malignant tumor originating from mesenchymal tissues. Bone mesenchymal stem cells-derived extracellular vesicles (BMSCs-EVs) can play important roles in OS. This study investigated the mechanism of BMSCs-EVs on OS. BMSC surface antigens and adipogenic and osteogenic differentiation were detected by flow cytometry, and oil red O and alizarin red staining. EVs were isolated from BMSCs by differential centrifugation and identified by transmission electron microscopy, nanoparticle tracking analysis, and Western blot (WB). miR-206 and neurensin-2 (NRSN2) levels in human osteoblast hFOB 1.19 or OS cells (143B, MG-63, Saos2, HOS) were detected by RT-qPCR. Human OS cells with lower miR-206 levels were selected and treated with BMSCs-EVs or pSUPER-NRSN2. The uptake of EVs by 143B cells, cell proliferation, apoptosis, invasion, and migration were detected by immunofluorescence, 5-ethynyl-2’-deoxyuridine (EdU) and colony formation assays, flow cytometry, scratch test, and transwell assays. The binding sites between miR-206 and NRSN2 were predicted by Starbase database and verified by dual-luciferase assay. The OS xenograft model was established and treated with BMSCs-EVs. Tumor growth rate and volume, cell proliferation, and p-ERK1/2, ERK1/2, and Bcl-xL levels were detected by vernier caliper, immunohistochemistry, and WB. BMSCs-EVs were successfully extracted. miR-206 was diminished and NRSN2 was promoted in OS cells. BMSCs-EVs inhibited proliferation, migration, and invasion, and promoted apoptosis of OS cells. BMSCs-EVs carried miR-206 into OS cells. Inhibition of miR-206 in EVs partially reversed the inhibitory effect of EVs on malignant behaviors of OS cells. miR-206 targeted NRSN2. Overexpression of NRSN2 reversed the inhibitory effect of EVs on OS cells. NRSN2 activated the ERK1/2-Bcl-xL pathway. BMSC-EVs inhibited OS growth in vivo. In summary, BMSC-EVs targeted NRSN2 and inhibited the ERK1/2-Bcl-xL pathway by carrying miR-206 into OS cells, thus inhibiting OS progression.

c-Myb-mediated inhibition of miR-601 in facilitating malignance of osteosarcoma via augmentation of PKMYT1

The crosstalk between osteosarcoma (OS) development and abnormally expressed microRNA (miR)-601 is not explored explicitly. Here, we identified the downregulated miR-601 in osteosarcoma (OS) through a comprehensive bioinformatics analysis of GEO Datasets. The results indicated that miR-601 was downregulated in both OS cells and tissues. The OS patients with reduced expression of miR-601 displayed worse prognosis. The results of in vitro and in vivo assay revealed that elevated miR-601 inhibited the proliferative, migratory and invasive capacities in OS cells. Mechanically, miR-601 exerted its function via targeting oncogene protein kinase membrane associated tyrosine/threonine 1 (PKMYT1) at post-transcriptional level. Moreover, miR-601 was attenuated by c-Myb at transcriptional level. Taken together, our studies reveal that miR-601 is a suppressive gene negatively correlated with malignancy of OS.

Beyond AOPs: A Mechanistic Evaluation of NAMs in DART Testing

New Approach Methodologies (NAMs) promise to offer a unique opportunity to enable human-relevant safety decisions to be made without the need for animal testing in the context of exposure-driven Next Generation Risk Assessment (NGRA). Protecting human health against the potential effects a chemical may have on embryo-foetal development and/or aspects of reproductive biology using NGRA is particularly challenging. These are not single endpoint or health effects and risk assessments have traditionally relied on data from Developmental and Reproductive Toxicity (DART) tests in animals. There are numerous Adverse Outcome Pathways (AOPs) that can lead to DART, which means defining and developing strict testing strategies for every AOP, to predict apical outcomes, is neither a tenable goal nor a necessity to ensure NAM-based safety assessments are fit-for-purpose. Instead, a pragmatic approach is needed that uses the available knowledge and data to ensure NAM-based exposure-led safety assessments are sufficiently protective. To this end, the mechanistic and biological coverage of existing NAMs for DART were assessed and gaps to be addressed were identified, allowing the development of an approach that relies on generating data relevant to the overall mechanisms involved in human reproduction and embryo-foetal development. Using the knowledge of cellular processes and signalling pathways underlying the key stages in reproduction and development, we have developed a broad outline of endpoints informative of DART. When the existing NAMs were compared against this outline to determine whether they provide comprehensive coverage when integrated in a framework, we found them to generally cover the reproductive and developmental processes underlying the traditionally evaluated apical endpoint studies. The application of this safety assessment framework is illustrated using an exposure-led case study.

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.

MicroRNA-21: A Critical Pathogenic Factor of Diabetic Nephropathy

Diabetic nephropathy (DN), one of the most common and intractable microvascular complications of diabetes, is the main cause of terminal renal disease globally. MicroRNA-21 (miR-21) is a kind of miRNA early identified in human circulation and tissues. Mounting studies have demonstrated that miR-21 plays an important role in the development and progression of DN. This collaborative review aimed to present a first attempt to capture the current evidence on the relationship between miR-21 and DN. After a systematic search, 29 relevant studies were included for comprehensively and thoroughly reviewing. All these eligible studies reported that miR-21 was up-regulated in DN, whether in serum or renal tissues of human or animal models. MiR-21 exhibited its pathogenic roles in DN by forming a complex network with targeted genes (e.g. MMP-9, Smad7, TIMP3, Cdk6, FOXO1, IMP3, and MMP2) and the signaling cascades (e.g. Akt/TORC1 signaling axis, TGF-β/NF-κB signaling pathways, TGF-β/SMAD pathway, CADM1/STAT3 signaling, and AGE-RAGE regulatory cascade), which resulted in epithelial-to-mesenchymal transition, extracellular matrix deposition, cytoskeletal remodeling, inflammation, and fibrosis. This review highlights that miR-21 is a pivotal pathogenic factor in the development of DN. It may serve as an attractive potential diagnostic, prognostic, and predictive biomarker for DN in clinical practice after further confirmation of the clinicopathological features and molecular mechanisms of miR-21-mediated DN.

Overexpression of Long Non-Coding RNA MIR22HG Represses Proliferation and Enhances Apoptosis via miR-629-5p/TET3 Axis in Osteosarcoma Cells

In this study, we evaluated the mechanism of long non-coding RNA MIR22 host gene (LncRNA MIR22HG) in osteosarcoma cells. Forty-eight paired osteosarcoma and adjacent tissues samples were collected and the bioinformatic analyses were performed. Target genes and potential binding sites of MIR22HG, microRNA (miR)-629-5p and tet methylcytosine dioxygenase 3 (TET3) were predicted by Starbase and TargetScan V7.2 and confirmed by dual-luciferase reporter assay. Cell Counting Kit-8, colony formation and flow cytometry assays were utilized to determine the viability, proliferation and apoptosis of transfected osteosarcoma cells. Pearson's analysis was introduced for the correlation analysis between MIR22HG and miR-629-5p in osteosarcoma tissue. Relative expressions of MIR22HG, miR-629-5p and TET3 were measured by quantitative real-time polymerase chain reaction or Western blot. MiR-629-5p could competitively bind with and was negatively correlated with MIR22HG, the latter of which was evidenced by the high expression of miR-629-5p and low expression of MIR22HG in osteosarcoma tissues. Overexpressed MIR22HG repressed the viability and proliferation but enhanced apoptosis of osteosarcoma cells, which was reversed by miR-629-5p upregulation. TET3 was the target gene of miR-629-5p, and the promotive effects of upregulated miR-629-5p on the viability and proliferation as well as its repressive effect on apoptosis were abrogated via overexpressed TET3. To sum up, overexpressed MIR22HG inhibits the viability and proliferation of osteosarcoma cells, which was achieved via regulation of the miR-629-5p/TET3 axis.

Downregulated lncRNA GAS5 and Upregulated miR-21 Lead to Epithelial-Mesenchymal Transition and Lung Metastasis of Osteosarcomas

Lung is the primary site of osteosarcoma metastasis, but the underlying genetic or epigenetic factors determining lung metastasis of osteosarcoma are unknown. In this study, we report the status of growth arrest specific 5 (GAS5) in lung metastatic osteosarcomas. GAS5 was generally downregulated in osteosarcoma patients (n = 24) compared to healthy controls (n = 10) and even more so in patients with lung metastatic disease(n = 11) compared to the patients without metastasis (n = 13). We also report a role of miR-21 in GAS5-mediated effects. Downregulation of GAS5 in hFOB 1.19 and U2OS osteosarcoma cells enhanced their migration and invasion, along with an upregulated epithelial–mesenchymal transition (EMT), as evidenced by downregulated E-cadherin and upregulated vimentin, ZEB1, and ZEB2. Downregulation of GAS5 also resulted in a significantly increased expression of miR-21. Moreover, downregulation of such elevated miR-21 was found to reverse the effects of GAS5 silencing. miR-21 was also found to be elevated in osteosarcoma patients with its levels particularly high in patients with lung metastasis. Our observations reveal a possible role of GAS5 and miR-21 in lung metastasis of osteosarcoma, presenting them as novel targets for therapy.

Tissue Engineering Through 3D Bioprinting to Recreate and Study Bone Disease

The applications of 3D bioprinting are becoming more commonplace. Since the advent of tissue engineering, bone has received much attention for the ability to engineer normal bone for tissue engraftment or replacement. While there are still debates on what materials comprise the most durable and natural replacement of normal tissue, little attention is given to recreating diseased states within the bone. With a better understanding of the cellular pathophysiology associated with the more common bone diseases, these diseases can be scaled down to a more throughput way to test therapies that can reverse the cellular pathophysiology. In this review, we will discuss the potential of 3D bioprinting of bone tissue in the following disease states: osteoporosis, Paget's disease, heterotopic ossification, osteosarcoma, osteogenesis imperfecta, and rickets disease. The development of these 3D bioprinted models will allow for the advancement of novel therapy testing resulting in possible relief to these chronic diseases.

Identification of osteosarcoma by microRNA-coupled nuclease digestion on interdigitated electrode sensor

Osteosarcoma is a type of tumor originating from the bone cells, most often from long bones. Children and adolescents are mainly affected by osteosarcoma. Identifying the condition with osteosarcoma is mandatory to provide proper treatment to the affected patients. This research work has introduced an identification of an osteosarcoma biomarker "miRNA-21" on the interdigitated electrochemical sensor by nuclease digestion. The target RNA sequence of miRNA-21 was hybridized to the capture DNA and placed on the sensing electrode surface with the aid of the biotin-streptavidin interaction. The unhybridized immobilized single-standard capture DNA was digested by S1-nuclease. The current response of the digestion level was considered as the duplex formation between the target and capture DNA. Using this technique, the detection limit of the target was reached to 1 fM and a similar response of current was noted with the target RNA-spiked human serum, indicating the selective identification of target RNA. Further, single mismatched, triple mismatched, and random miRNA sequences (miRNA-195) failed to interact with the immobilized capture DNA, representing the specific identification of target RNA. This nuclease digestion technique with miRNA-21 identification helps in detecting osteosarcoma and related issues.

Regulation of microRNA-21 expression by natural products in cancer

Natural products have been of much interest in research studies owing to their wide pharmacological applications, chemical diversity, low side effects, and multitarget activities. Examples of these compounds include matrine, sulforaphane, silibinin, curcumin, berberin, resveratrol, and quercetin. Some of the present anticancer drugs, such as taxol, vincristine, vinblastine, and doxorubicin are also derived from natural products. The anti-carcinogenic effects of these products are partly mediated through modulation of microRNA-21 (miR-21) expression. To date, numerous downstream targets of miR-21 have been recognized, which include phosphatase and tensin homolog (PTEN), ras homolog gene family member B (RHOB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), programmed cell death 4 (PDCD4), signal transducer and activator of transcription (STAT)-3, and nuclear factor kappa B (NF-κB) pathways. These signaling pathways, their regulation by oncomiR-21 in cancer, and the modulating impact of natural products are the main focus of this review.

Mesyl phosphoramidate backbone modified antisense oligonucleotides targeting miR-21 with enhanced in vivo therapeutic potency

The design of modified oligonucleotides that combine in one molecule several therapeutically beneficial properties still poses a major challenge. Recently a new type of modified mesyl phosphoramidate (or µ-) oligonucleotide was described that demonstrates high affinity to RNA, exceptional nuclease resistance, efficient recruitment of RNase H, and potent inhibition of key carcinogenesis processes in vitro. Herein, using a xenograft mouse tumor model, it was demonstrated that microRNA miR-21-targeted µ-oligonucleotides administered in complex with folate-containing liposomes dramatically inhibit primary tumor growth via long-term down-regulation of miR-21 in tumors and increase in biosynthesis of miR-21-regulated tumor suppressor proteins. This antitumoral effect is superior to the effect of the corresponding phosphorothioate. Peritumoral administration of µ-oligonucleotide results in its rapid distribution and efficient accumulation in the tumor. Blood biochemistry and morphometric studies of internal organs revealed no pronounced toxicity of µ-oligonucleotides. This new oligonucleotide class provides a powerful tool for antisense technology.

MiR-455-3p downregulation facilitates cell proliferation and invasion and predicts poor prognosis of osteosarcoma

Background

Osteosarcoma (OS) is one of the most primary malignant bone tumors, mainly attracting children and young adults. The microRNAs are mentioned to play vital roles in many cancers, including OS. The purpose of this study was to explore the expression and function of miR-455-3p in OS and predict the potential effects in clinical diagnosis and prognosis.

Method

We conducted quantitative real-time PCR to assess the expression of miR-455-3p in OS tissues and cell lines. The Cell Counting Kit-8 assay, Transwell assay, and flow cytometry were performed to assess the ability of miR-455-3p on cell proliferation, migration, invasion, and apoptosis. Kaplan–Meier curve and Cox regression analysis were used to demonstrate the survival outcome.

Results

This study revealed that the expression of miR-455-3p was decreased in OS tissues and cell lines. The dysregulation of miR-455-3p was in association with tumor size, distant metastasis, and clinical stage. Patients with high miR-455-3p expression had a satisfying survival rate. Multivariate Cox analysis indicated that miR-455-3p was a promising prognostic indicator. Expression of miR-455-3p could inhibit the proliferation, migration, and invasion, and facilitate apoptosis of OS cells in vitro.

Conclusion

These results indicated the miR-455-3p was a potential clinical therapeutic target and prognostic biomarker by suppressing the proliferation, migration, and invasion, as well as enhancing cell apoptosis.

LNC473 Regulating APAF1 IRES-Dependent Translation via Competitive Sponging miR574 and miR15b: Implications in Colorectal Cancer

A growing number of studies have focused on the involvement of non-coding RNAs (ncRNAs) in the internal ribosome entry site (IRES)-mediated translation in tumorigenesis; however, the underlying mechanisms in colorectal cancer (CRC) remain elusive. In this study, we show that LINC00473 (LNC473) exerted its functions as a tumor suppressor in promoting apoptotic protease-activating factor 1 (APAF1) IRES activity through competitively sponging miR574-5p and miR15b-5p in CRC initiation and pathogenesis. Specifically, LNC473 and its downstream target APAF1 were significantly downregulated accompanied by upregulated miR574-5p and miR15b-5p in CRC cells and tissues, which had a significant prognostic impact on clinical outcomes in our CRC cohort (n = 157). Furthermore, ectopic LNC473 significantly sponged endogenous miR574-5p or miR15b-5p and thereby inhibited cell proliferation and colony formation capacity, and it accelerated cell apoptosis through activating the APAF1-CASP9-CASP3 pathway. Notably, LNC473 overexpression resulted in dramatic promotion of APAF1 IRES activity and translation, whereas rescue experiments confirmed the recovery by the existence of LNC473 and miR574/15b-5p. Mechanistically, LNC473 overexpression promoted IRES binding domain exposure and removed the constraints controlling from miR574-5p and miR15b-5p, and subsequently enhanced IRES-mediated APAF1 expression in vitro and in vivo. Therefore, our results uncover a novel LNC473-miR574/miR15b-APAF1 signaling axis, which provides new targets and crosstalk regulation mechanism for CRC prevention and treatment.

PTPN14, a target gene of miR-4295, restricts the growth and invasion of osteosarcoma cells through inactivation of YAP1 signalling

Non-receptor tyrosine phosphatase 14 (PTPN14) has emerged as a novel tumour-suppressor in a wide range of human cancer types. However, the role of PTPN14 in osteosarcoma remains undetermined. In the present study, we aimed to explore the expression pattern, biological function, and regulation of PTPN14 in osteosarcoma. Low PTPN14 expression levels were detected in osteosarcoma cells, and PTPN14 overexpression markedly decreased the proliferation, colony formation, and invasive potential of osteosarcoma cells. Bioinformatics analysis predicted PTPN14 as a potential target gene of microRNA-4295 (miR-4295), and this prediction was validated by a dual-luciferase reporter assay. PTPN14 expression was negatively modulated by miR-4295 in osteosarcoma cells. Moreover, PTPN14 expression was inversely correlated with miR-4295 expression in osteosarcoma tissues. Notably, miR-4295 inhibition significantly restricted the proliferation and invasion of osteosarcoma cells. PTPN14 overexpression or miR-4295 inhibition increased the phosphorylation of Yes-associated protein 1 (YAP1) and impeded YAP1 nuclear translocation, leading to inhibition of YAP1-mediated transcriptional activity. However, the miR-4925-inhibition-mediated antitumour effect was partially reversed by PTPN14 knockdown. Overall, these results demonstrate that PTPN14 is a miR-4295 target gene and it exerts a tumour-suppressive function in osteosarcoma cells via inactivation of YAP1. Our study uncovers a miR-4295-PTPN14-YAP1 signalling pathway that may play a crucial role in the progression of osteosarcoma.

3D DNA nanonet structure coupled with target-catalyzed hairpin assembly for dual-signal synergistically amplified electrochemical sensing of circulating microRNA

DNA nanomaterials are reliable and powerful tools in the development of a variety of biosensors owing to their notable self-assembly ability and precise recognition capability. Here, we propose a DNA nanomaterial-based system for the dual-amplified electrochemical sensing of circulating microRNAs by a coupled cascade of catalyzed hairpin assembly (CHA) and three-dimensional (3D) DNA nanonet structure. In the target-assisted CHA process, the stable hairpin structures H1 and H2 act as probes for the recognition and recycling of circulating microRNAs, leading to the formation of abundant H1-H2 duplexes with tails. Subsequently, a 3D DNA nanonet structure was introduced, which was assembled using three DNA strands constructed X-DNA monomers as the building blocks, and hybridized to the tails of H1-H2 duplexes. The successful integration of target-assisted CHA and 3D DNA nanonet structure induced the second signal amplification. The designed biosensor performed under optimized experimental conditions, and exposed admirable analytical performance for the detection of circulating miR-21, with a wide linear range from 10 fM to 1 nM, high sensitivity of limit of detection (LOD) of 3.6083 fM, good specificity in the face of single nucleotides and other microRNAs, satisfactory stability and reproducibility for practical analysis. Furthermore, the clinical applicability for circulating miR-21 detection was verified in human serum samples without additional treatment. We hope that this elaborated biosensor will provide new opportunities for bioassays based on DNA nanomaterials.

Role of exosomal miR‑21 in the tumor microenvironment and osteosarcoma tumorigenesis and progression (Review)

Osteosarcoma is the most common bone tumor affecting both adolescents and children. Early detection is critical for the effective treatment of the disease. Derived from cancer cells, miR‑21 contained within exosomes in the tumor microenvironment may act on both cancer cells and the surrounding tumor microenvironment (TME), including immune cells, endothelial cells and fibroblasts. In human serum and plasm, the level of exosomal miR‑21 between osteosarcoma patients and healthy controls differs, supporting the role of miR‑21 as a biomarker for osteosarcoma. The involvement of a number of miR‑21 target genes in tumor progression suggests that miR‑21 may significantly affect the plasticity of cancer cells, leading to tumor progression, metastasis, angiogenesis and immune escape in osteosarcoma. Understanding the biogenesis and functions of exosomal miR‑21 is of great value for the diagnosis and therapy of cancer, including osteosarcoma. The present review discusses the role of miR‑21 in the tumor microenvironment, and in the development and progression of osteosarcoma, with an aim to summarize the functions of this miRNA in cancer.

Overexpression of microRNA-96 is associated with poor prognosis and promotes proliferation, migration and invasion in cholangiocarcinoma cells via MTSS1

MicroRNA-96 (miR-96) has been revealed serve an oncogenic role in various types of cancer. However, the role of miR-96 in cholangiocarcinoma (CCA) development and progression is yet to be elucidated. Thus, the aim of the present study was to investigate the role of miR-96 in CCA. The expression pattern of miR-96 in CCA tissues and cell lines was evaluated using reverse transcription-quantitative PCR analysis. Kaplan-Meier curves and Cox regression analyses were conducted to investigate the prognostic significance of miR-96 in CCA. Cell Counting Kit-8 and Transwell assays were performed to identify the functions of miR-96. The association between miR-96 and metastasis suppressor-1 (MTSS1) was verified using a dual-luciferase assay. The results demonstrated that miR-96 expression levels were increased in CCA tissues and cell lines compared with those in adjacent normal tissues and normal human intrahepatic biliary epithelial cell lines, respectively. High expression levels of miR-96 were significantly associated with lymph node metastasis, differentiation and TNM stage. In addition, upregulated expression of miR-96 was associated with a poorer prognosis and was predicted to be a prognostic factor in patients with CCA. Overexpression of miR-96 in vitro promoted CCA cell proliferation, migration and invasion. Additionally, MTSS1 was identified as a direct target of miR-96. The results of the present study indicated the clinical and biological importance of miR-96 as an oncogene in CCA. miR-96 may represent an independent prognostic biomarker and may promote CCA cell proliferation, migration and invasion by targeting MTSS1.

Biological and Clinical Relevance of microRNAs in Mitochondrial Diseases/Dysfunctions

Mitochondrial dysfunction arises from an inadequate number of mitochondria, an inability to provide necessary substrates to mitochondria, or a dysfunction in their electron transport and a denosine triphosphate synthesis machinery. Occurrences of mitochondrial dysfunction are due to genetic or environmental changes in the mitochondria or in the nuclear DNA that codes mitochondrial components. Currently, drug options are available, yet no treatment exists in sight of this disease and needs a new insight into molecular and signaling pathways for this disease. microRNAs (miRNAs) are small, endogenous, and noncoding RNAs function as a master regulator of gene expression. The evolution of miRNAs in the past two decades emerged as a key regulator of gene expression that controls physiological pathological cellular differentiation processes, and metabolic homeostasis such as development and cancer. It has been known that miRNAs are a potential biomarker in both communicable and noncommunicable diseases. But, in the case of mitochondrial dysfunction in miRNAs, the number of studies and investigations are comparatively less than those on other diseases and dysfunctions. In this review, we have elaborated the roles of miRNAs in the mitochondrial diseases and dysfunctions.

The Role of miRNA in the Diagnosis, Prognosis, and Treatment of Osteosarcoma

Osteosarcoma (OS) is one of the most common malignant tumors derived from mesenchymal tissue and is highly invasive, mainly in children and adolescents. Treatment of OS is mostly based on standard treatment options, including aggressive surgical resection, systemic chemotherapy, and targeted radiation therapy, but the 5-year survival rate is still low. MicroRNA (miRNA) is a highly conserved type of endogenous nonprotein-encoding RNA, about 19-25 nucleotides in length, whose transcription process is independent of other genes. Generally, miRNAs play a role in regulating cell proliferation, differentiation, apoptosis, and development by binding to the 3' untranslated region of target mRNAs, whereby they can degrade or induce translational silencing. Although miRNAs play a regulatory role in various metabolic processes, they are not translated into proteins. Several studies have shown that miRNAs play an important role in the diagnosis, treatment, and prognosis of OS. Herein, the authors describe new advances in the diagnosis, prognosis, and treatment of miRNAs in OS.

Elimination of Osteosarcoma by Necroptosis with Graphene Oxide-Associated Anti-HER2 Antibodies

The prognosis for non-resectable or recurrent osteosarcoma (OS) remains poor. The finding that the majority of OS overexpress the protooncogene HER2 raises the possibility of using HER2 as a therapeutic target. However, clinical trials on the anti-HER2 antibody trastuzumab (TRA) in treating OS find no therapeutic benefit. HER2 overexpression in OS is not generally associated with gene amplification, with low-level expression regarded as HER2 “negative”, as per criteria used to classify breast cancer HER2 status. Nevertheless, active HER2-targeting approaches, such as virus-based HER2 vaccines or CAR-T cells have generated promising results. More recently, it has been found that the noncovalent association of TRA with nanomaterial graphene oxide (GO) generates stable TRA/GO complexes capable of rapidly killing OS cells. TRA/GO induces oxidative stress and strong HER2 signaling to elicit immediate degradation of both cIAP (cellular inhibitor of apoptosis protein) and caspase 8, leading to activation of necroptosis. This is an attractive mechanism of cancer cell death as chemo/apoptosis-resistant tumors may remain susceptible to necroptosis. In addition, necroptosis is potentially immunogenic to promote tumor immunity, as opposed to apoptosis that tends to silence tumor immunity. Currently, no established anticancer therapeutics are known to eliminate cancers by necroptosis. The aim of this article is to review the rationale and mechanisms of TRA/GO-mediated cytotoxicity.