Retracted : Knockdown of lncRNA MEG3 inhibits viability, migration, and invasion and promotes apoptosis by sponging miR‐127 in osteosarcoma cell

Bta-miR-127 inhibits secretion, proliferation and promotes apoptosis by targeting ITGA6 in bovine Sertoli cell

Sertoli cell (SC) play a critical role in the spermatogenesis process involved in male fecundity and reproductive potential. SC development is regulated by microRNAs (miRNAs). However, the effect and molecular mechanism of miRNAs and target genes on bovine immature SC remains poorly understood. In this study, bta-miR-127 overexpression in SC inhibited cell secretion, proliferation, cell viability, and S-phase cells number. However, inhibition of bta-miR-127 had the opposite effect. An over-expression of bta-miR-127 significantly promotes SC apoptosis, and bta-miR-127 inhibition can significantly inhibit this process. These results reveal that bta-miR-127 is an inhibitor of SC proliferation and secretion. A combination of transcriptome sequencing, bioinformatics analysis, and dual-luciferase reporter assay showed that ITGA6 was targeted by bta-miR-127. The small interfering RNA of ITGA6 (si-ITGA6) inhibits SC proliferation and secretion, as well as promotes apoptosis. The SC proliferation and secretion marker genes, cell viability, and S phase cell number in co-transfected si-ITGA6 + miR-127 inhibitor was significantly lower than those of the bta-miR-127 inhibitor group. These results further confirmed that bta-miR-127 targeting ITGA6 inhibits the SC proliferation and secretion, and promotes SC apoptosis. These findings proposed a novel miRNA (bta-miR-127) that impeded bovine SC proliferation and promoted SC apoptosis through downregulation of ITGA6.

Cellular and Genetic Background of Osteosarcoma

Osteosarcoma describes a tumor of mesenchymal origin with an annual incidence rate of four to five people per million. Even though chemotherapy treatment has shown success in non-metastatic osteosarcoma, metastatic disease still has a low survival rate of 20%. A targeted therapy approach is limited due to high heterogeneity of tumors, and different underlying mutations. In this review, we will summarize new advances obtained by new technologies, such as next generation sequencing and single-cell sequencing. These new techniques have enabled better assessment of cell populations within osteosarcoma, as well as an understanding of the molecular pathogenesis. We also discuss the presence and properties of osteosarcoma stem cells-the cell population within the tumor that is responsible for metastasis, recurrence, and drug resistance.

The Mechanisms of BDNF Promoting the Proliferation of Porcine Follicular Granulosa Cells: Role of miR-127 and Involvement of the MAPK-ERK1/2 Pathway

As a member of the neurotrophic family, brain-derived neurotrophic factor (BDNF) provides a key link in the physiological process of mammalian ovarian follicle development, in addition to its functions in the nervous system. The emphasis of this study lay in the impact of BDNF on the proliferation of porcine follicular granulosa cells (GCs) in vitro. BDNF and tyrosine kinase B (TrkB, receptor of BDNF) were detected in porcine follicular GCs. Additionally, cell viability significantly increased during the culture of porcine GCs with BDNF (100 ng/mL) in vitro. However, BDNF knockdown in GCs decreased cell viability and S-phase cells proportion-and BDNF simultaneously regulated the expression of genes linked with cell proliferation (CCND1, p21 and Bcl2) and apoptosis (Bax). Then, the results of the receptor blocking experiment showed that BDNF promoted GC proliferation via TrkB. The high-throughput sequencing showed that BDNF also regulated the expression profiles of miRNAs in GCs. The differential expression profiles were obtained by miRNA sequencing after BDNF (100 ng/mL) treatment with GCs. The sequencing results showed that, after BDNF treatment, 72 significant differentially-expressed miRNAs were detected-5 of which were related to cell process and proliferation signaling pathways confirmed by RT-PCR. Furthermore, studies showed that BDNF promoted GCs' proliferation by increasing the expression of CCND1, downregulating miR-127 and activating the ERK1/2 signal pathway. Moreover, BDNF indirectly activated the ERK1/2 signal pathway by downregulating miR-127. In conclusion, BDNF promoted porcine GC proliferation by increasing CCND1 expression, downregulating miR-127 and stimulating the MAPK-ERK1/2 signaling cascade.

Molecular mechanism of microRNAs regulating apoptosis in osteosarcoma

Osteosarcoma is a primary malignant bone tumor with no effective treatment. Apoptosis, one of the programmed cell death, is any pathological form of cell death mediated by intracellular processes. Under the pathological state, the de-regulated regulation of apoptosis can disrupt the balance between cell proliferation and death, causing osteosarcoma proliferation and metastasis. As carcinogenic or tumor suppressor factors, microRNAs (miRNAs) regulate apoptosis of osteosarcoma cells by regulating apoptosis-related genes and apoptosis-related signaling pathways, such as mitochondrial apoptosis pathway, death receptor pathway, and endoplasmic reticulum pathway. Meanwhile as these abnormal miRNAs can be stored and transported by exosomes, detecting exosomes can be seen an effective method to diagnose osteosarcoma in the early stage. This review provides the current knowledge of miRNAs and their target genes related to the apoptosis of osteosarcoma, summarizes abnormal expression and regulation of miRNAs and signaling pathways in osteosarcoma and prospects the detection of exosome as a method for early diagnosis of osteosarcoma.

Engineered exosome as targeted lncRNA MEG3 delivery vehicles for osteosarcoma therapy

Exosomes as nanosized membrane vesicles, could targeted deliver therapeutic agents by modification with target ligands. Exosome-derived non-coding RNAs play a vital role in the development of tumors. Previous evidences reveal that long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) has anti-tumor properties. Whereas, the inhibitory effects of exosome-derived lncRNA MEG3 in osteosarcoma (OS) remain largely unknown. In this study, we utilize the engineering technology to combine exosome and lncRNA for tumor-targeting therapy of OS. We elucidated the anti-OS effects of lncRNA MEG3, and then prepared the c(RGDyK)-modified and MEG3-loaded exosomes (cRGD-Exo-MEG3). The engineered exosomes cRGD-Exo-MEG3 could deliver more efficiently to OS cells both in vitro and in vivo. In this way, cRGD-Exo-MEG3 facilitate the anti-OS effects of MEG3 significantly, with the help of enhanced tumor-targeting therapy. This study elucidates that engineered exosomes as targeted lncRNA MEG3 delivery vehicles have potentially therapeutic effects for OS.

LncRNA UCC promotes epithelial-mesenchymal transition via the miR-143-3p/SOX5 axis in non-small-cell lung cancer

Long non-coding RNAs (lncRNAs) have been found to play regulatory roles in cancers; for example, UCC was reported to promote colorectal cancer progression. However, the function of UCC in non-small-cell lung cancer (NSCLC) remains unclear. Therefore, mRNA and protein levels were assessed using qPCR and western blots. Cell viability was assessed by colony-formation assays. The interaction between lncRNAs and miRNAs was detected by dual-luciferase reporter and RIP assays. The tumorigenesis of NSCLC cells in vivo was determined by xenograft assays. LncRNA UCC was highly expressed in both NSCLC tissues and cells. Knockdown of UCC expression suppressed the proliferation of NSCLC cells. In addition, a dual-luciferase reporter system and RIP assays showed that UCC specifically bound to miR-143-3p and acted as a sponge of miR-143-3p in NSCLC cells. The miR-143-3p inhibitor rescued the inhibitory effect of sh-UCC on the proliferation of NSCLC cells. Moreover, miR-143-3p and UCC showed opposite effects on the expression of SOX5, which promoted EMT in NSCLC cells. In addition, in a mouse model, knockdown of UCC expression alleviated EMT and NSCLC progression in vivo, which was consistent with the in vitro results. In the current study, we found that UCC induced the proliferation and migration of NSCLC cells both in vitro and in vivo by inducing the expression of SOX5 via miR-143-3p and subsequently promoted EMT in NSCLC.

Oncogenic functions of ZEB1 in pediatric solid cancers: interplays with microRNAs and long noncoding RNAs

The transcription factor Zinc finger E-box binding 1 (ZEB1) displays a range of regulatory activities in cell function and embryonic development, including driving epithelial-mesenchymal transition. Several aspects of ZEB1 function can be regulated by its functional interactions with noncoding RNA types, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). Increasing evidence indicates that ZEB1 importantly influences cancer initiation, tumor progression, metastasis, and resistance to treatment. Cancer is the main disease-related cause of death in children and adolescents. Although the role of ZEB1 in pediatric cancer is still poorly understood, emerging findings have shown that it is expressed and regulates childhood solid tumors including osteosarcoma, retinoblastoma, neuroblastoma, and central nervous system tumors. Here, we review the evidence supporting a role for ZEB1, and its interplays with miRNAs and lncRNAs, in pediatric cancers.

lncRNA MEG3 Downregulation Relieves Intracerebral Hemorrhage by Inhibiting Oxidative Stress and Inflammation in an miR-181b-Dependent Manner

BACKGROUND This study was designed to illustrate the effects and latent mechanism of lncRNA maternally expressed gene 3 (MEG3) on intracerebral hemorrhage (ICH)-induced brain injury. MATERIAL AND METHODS An ICH rat model was generated to determine the role of lncRNA MEG3 in ICH. The interaction between lncRNA MEG3 and microRNA (miR)-181b were confirmed by Starbase and dual-luciferase reporter assay. One hour (h) or 3 days after ICH stimulation, rat neurological injury was evaluated by modified Neurological Severity Score (mNSS). Brain water content and cell apoptosis were assessed using brain edema assessment and flow cytometry (FCM), respectively. Caspase3 activity was also determined. Enzyme-linked immunosorbent assay (ELISA) was applied to evaluate the levels of pro-inflammatory cytokines. Moreover, the representative biomarkers of oxidative stress were evidenced using detection kits. RESULTS The lncRNA MEG3 level in ICH rat brain tissues was higher than that in the sham group. miR-181b was a direct target of lncRNA MEG3 and it was downregulated in brain tissues of ICH rats. Notably, we found that neurobehavioral scores, brain water content, and neuronal apoptosis were decreased and caspase3 activity was reduced in MEG3-shRNA-treated ICH rats, while we observed the opposite result in ICH+MEG3-shRNA+miR-181b inhibitor rats. Further analyses revealed that MEG3-shRNA inhibited inflammatory cytokines release and reduced oxidative stress. All these results were reversed by miR-181b inhibitor. In addition, MEG3-shRNA activated the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) pathway, which was reversed by miR-181b inhibitor. CONCLUSIONS MEG3-shRNA restrained oxidative stress and inflammation following ICH in an miR-181b-dependent manner.

LncRNA BRCAT54 inhibits the tumorigenesis of non-small cell lung cancer by binding to RPS9 to transcriptionally regulate JAK-STAT and calcium pathway genes

OBJECTIVES

Increasing evidence suggest that long non-coding RNAs (lncRNAs) play critical roles in cancers. However, the expression pattern and underlying mechanisms of lncRNAs in non-small cell lung cancer (NSCLC) remain incompletely understood. This study aimed to elucidate the functions and molecular mechanisms of a certain lncRNA in NSCLC.

METHODS

LncRNA microarray was performed to identify differential expressed lncRNAs between pre- and postoperation plasma in NSCLC patients. The expression level of candidate lncRNA in NSCLC tissues, plasma and cells was determined by quantitative real-time PCR (qRT-PCR) and in situ hybridization. The functional roles of lncRNA were assessed in vitro and in vivo. Furthermore, RNA pull-down, RNA immunoprecipitation, microarray, qRT-PCR and rescue assays were conducted to explore the mechanism action of lncRNA in NSCLC cells.

RESULTS

We identified a novel lncRNA (BRCAT54), which was significantly upregulated in preoperative plasma, NSCLC tissues and NSCLC cells, and its higher expression was associated with better prognosis in patients with NSCLC. Overexpression of BRCAT54 inhibited proliferation, migration and activated apoptosis in NSCLC cells. Conversely, knockdown of BRCAT54 reversed the suppressive effects of BRCAT54. Moreover, overexpression of BRCAT54 repressed NSCLC cell growth in vivo. Mechanistically, BRCAT54 directly bound to RPS9. Knockdown of RPS9 substantially reversed the promoting effects of si-BRCAT54 on cell proliferation and enhanced the inhibitive effect of si-BRCAT54 on BRCAT54 expression. In addition, silencing of RPS9 activated JAK-STAT pathway and suppressed calcium signaling pathway gene expressions.

CONCLUSION

This study identified BRCAT54 as a tumor suppressor in NSCLC. Targeting the BRCAT54 and RPS9 feedback loop might be a novel therapeutic strategy for NSCLC.

Functional interplay between long non-coding RNAs and the Wnt signaling cascade in osteosarcoma

Osteosarcoma is a common and highly malignant bone tumor among children, adolescents and young adults. However, the underlying molecular mechanisms remain largely unexplored. LncRNAs are transcripts with no or limited protein-coding capacity in human genomes, and have been demonstrated to play crucial functions in initiation, progression, therapeutic resistance, recurrence and metastasis of tumor. Considerable studies revealed a dysregulated lncRNA expression pattern in osteosarcoma, which may act as oncogenes or suppressors to regulate osteosarcoma progression. Wnt signaling pathway is an important cascade in tumorigenesis by modulation of pleiotropic biological functions including cell proliferation, apoptosis, differentiation, stemness, genetic stability and chemoresistance. Hyperactivation or deficiency of key effectors in Wnt cascade is a common event in many osteosarcoma patients. Recently, increasing evidences have suggested that lncRNAs could interplay with component of Wnt pathway, and thereby contribute to osteosarcoma onset, progression and dissemination. In this review, we briefly summarize Wnt signaling-related lncRNAs in osteosarcoma progression, aiming to gain insights into their underlying crosstalk as well as clinical application in osteosarcoma therapeutic modalities.

Long noncoding RNA LINC01296 plays an oncogenic role in colorectal cancer by suppressing p15 expression

OBJECTIVE

To examine the role of the long noncoding RNA LINC01296 in colorectal carcinoma (CRC) and to explore the underlying mechanism.

METHODS

We detected LINC01296 expression levels in a cohort of 51 paired CRC and normal tissues. We also assessed the effects of LINC01296 on cell proliferation and apoptosis in CRC cells in vitro, and measured its effect on tumor growth in an in vivo mouse model. We identified the potential downstream targets of LINC01296 and assessed its regulatory effects.

RESULTS

Expression levels of LINC01296 were elevated in 37/51 CRC tissues compared with the corresponding normal tissues and were significantly associated with tumor stage, lymph node metastasis, and distant metastasis. Knockdown of LINC01296 using antisense oligonucleotides inhibited cell proliferation and promoted apoptosis of colon cancer cells in vitro and inhibited tumor growth in vivo. Knockdown of LINC01296 also significantly increased the gene expression of p15 in colon cancer cells. LINC01296-specific suppression of p15 was validated by the interaction between enhancer of zeste homolog 2 and LINC01296.

CONCLUSION

Overexpression of LINC01296 suppressed the expression of p15 leading to CRC carcinogenesis. These findings may provide the basis for novel future CRC-targeted therapies.

LncRNA lnc_13814 promotes the cells apoptosis in granulosa cells of duck by acting as apla-miR-145-4 sponge

Follicle development is a vital factor which determines the reproductive performance of poultry. Long noncoding RNAs (lncRNAs) have been reported to maintain animal reproductive function and play key roles in ovarian development and hormone secretion. But the regulatory mechanism of lncRNAs in duck follicle development has seldom been reported. In this study, to better explore the molecular mechanism of follicle development in ducks, the follicular lncRNA was sequenced and analyzed. A total of 9,551 lncRNAs were predicted in the duck follicles. Four hundred and forty-five lncRNAs were differentially expressed between the white follicles and yellow follicles. The results of our studies showed that lnc_13814 promoted cell apoptosis in duck GCs. Furthermore, the bioinformatics analysis results demonstrated that lnc_13814 was involved in a lncRNA-miRNA-mRNA coexpression network and it was observed to sponge two follicle-related miRNAs by a luciferase activity assay. Moreover, we found that overexpression of lnc_13814 significantly increased DNA damage inducible transcript 3 (DDIT3) expression and downregulated GCs apoptosis. Finally, we found that lnc_13814 directly binds to and inhibits apla-mir-145-4; then, lnc_13814 increases the expression of DDIT3 and up-regulates GCs apoptosis. Taken together, our findings demonstrate that lncRNAs have potential effects on duck ovarian follicles and lncRNAs may represent a new approach to understand follicular development.

Overexpression of miR-127 Predicts Poor Prognosis and Contributes to the Progression of Papillary Thyroid Cancer by Targeting REPIN1

Papillary thyroid cancer (PTC) is a major kind of thyroid cancer with increasing recurrence and metastasis. MiR-127 has been demonstrated to play roles in many cancers with dysregulation. However, the function of miR-127 is still unknown. This study aimed to explore a novel biomarker for the progression and prognosis of PTC. A set of 118 patients with PTC were collected from the Affiliated Hospital of Qingdao University. qRT-PCR was used to detect the expression of miR-127 in PTC tissues and cells. The association between miR-127 expression and the clinicopathological features of patients were evaluated by the χ² test, and the prognostic value of miR-127 was evaluated by Kaplan-Meier analysis and Cox regression analysis. The effect of miR-127 on cell proliferation, migration, and invasion of PTC was analyzed by CCK-8 and transwell assay. miR-127 was found to be upregulated in PTC tissues and cells correlated with the TNM stage and poor prognosis of PTC patients. MiR-127 and the TNM stage were considered as two independent prognostic indicators for PTC. Moreover, overexpression of miR-127 significantly enhanced cell proliferation, migration, and invasion of PTC by targeting REPIN1. miR-127 may be involved in the progression of PTC, which provides a new therapeutic strategy for PTC.

Long non-coding RNA MEG3 silencing and microRNA-214 restoration elevate osteoprotegerin expression to ameliorate osteoporosis by limiting TXNIP

Studies have shown that long non-coding RNA (lncRNA) MEG3 plays a key role in osteoporosis (OP), but its regulatory mechanism is somewhat incompletely clear. Here, we intend to probe into the mechanism of MEG3 on OP development by modulating microRNA-214 (miR-214) and thioredoxin-interacting protein (TXNIP). Rat models of OP were established. MEG3, miR-214 and TXNIP mRNA expression in rat femoral tissues were detected, along with TXNIP, OPG and RANKL protein expression. BMD, BV/TV, Tb.N and Tb.Th in tissue samples were measured. Ca, P and ALP contents in rat serum were also determined. Primary osteoblasts were isolated and cultured. Viability, COL-I, COL-II and COL-Χ mRNA expression, PCNA, cyclin D1, OCN, RUNX2 and osteolix protein expresion, ALP content and activity, and mineralized nodule area of rat osteoblasts were further detected. Dual-luciferase reporter gene and RNA-pull down assays verified the targeting relationship between MEG3, miR-214 and TXNIP. MEG3 and TXNIP were up-regulated while miR-214 was down-regulated in femoral tissues of OP rats. MEG3 silencing and miR-214 overexpression increased BMD, BV/TV, Tb.N, Tb.Th, trabecular bone area, collagen area and OPG expression, and down-regulated RANKL of femoral tissues in OP rats. MEG3 silencing and miR-214 overexpression elevated Ca and P and reduced ALP in OP rat serum, elevated osteoblast viability, differentiation ability, COL-I and COL-Χ expression and ALP activity, and reduced COL-II expression of osteoblasts. MEG3 specifically bound to miR-214 to regulate TXNIP. MEG3 silencing and miR-214 overexpression promote proliferation and differentiation of osteoblasts in OP by down-regulating TXNIP, which further improves OP.

Identifying biomolecules and constructing a prognostic risk prediction model for recurrence in osteosarcoma

INTRODUCTION

Osteosarcoma is a high-morbidity bone cancer with an unsatisfactory prognosis. The aim of this study is to develop novel potential prognostic biomarkers and construct a prognostic risk prediction model for recurrence in osteosarcoma.

METHODS

By analyzing microarray data, univariate and multivariate Cox regression analyses were performed to screen prognostic RNA signatures and to build a prognostic model. The RNA signatures were validated using Kaplan-Meier curves. Then, we developed and validated a nomogram combining age, recurrence, metastatic, and Prognostic score (PS) models to predict the individual's overall survival at the 3- and 5-year points. Pathway enrichment of RNA was conducted based on the significant co-expressed RNAs.

RESULTS

A total of 319 mRNAs and 14 lncRNAs were identified in the microarray data. One lncRNA (LINC00957) and six mRNAs (METL1, CA9, B3GALT4, ALDH1A1, LAMB3, and ITGB4) were identified as RNA signatures and showed good performances in survival prediction for both the training and validation cohorts. Cox regression analysis showed that the seven RNA signatures could independently predict overall survival. Furthermore, age, recurrence, metastatic, and PS models were identified as independent prognostic factors via univariate and multivariate Cox analyses (P < 0.05) and included in the prognostic nomogram. The C-index values for the 3- and 5-year overall survival predictions of the nomogram were 0.809 and 0.740, respectively.

CONCLUSIONS

The current study provides the novel potential of seven RNA candidates as prognostic biomarkers. Nomograms were constructed to provide accurate and individualized survival prediction for recurrence in osteosarcoma patients.

Identification of Serum Exosomal MicroRNA Expression Profiling in Menopausal Females with Osteoporosis by High-throughput Sequencing

Estrogen deficiency, which mainly occurs in postmenopausal women, is a primary reason for osteoporosis in clinical diagnosis. However, the molecular regulation of osteoporosis in menopausal females is still not adequately explained in the literature, with the diagnosis and treatment for osteoporosis being limited. Herein, exosomal microRNAs (miRNAs) were used to evaluate their diagnosis and prediction effects in menopausal females with osteoporosis. In this study, 6 menopausal females without osteoporosis and 12 menopausal females with osteoporosis were enrolled. The serum exosomes were isolated, and the miRNA expression was detected by miRNA high-throughput sequencing. Exosomal miRNA effects were analyzed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses. The miRNA-targeted genes were evaluated by Targetscan 7.2 and the protein-protein interactions (PPI) by STRING. Hub genes were analyzed by the CytoHubba app of Cytoscape. The results showed that 191 aberrant miRNAs were found in the group of menopausal females with osteoporosis, including 72 upregulated miRNAs and 121 downregulated miRNAs. Aberrant miRNAs were involved in many signaling pathways, such as the Wnt, MAPK, and Hippo pathways. Based on PPI network analysis, FBXL3, FBXL13, COPS2, UBE2D3, DCUN1D1, DCUN1D4, CUL3, FBXO22, ASB6, and COMMD2 were the 10 most notable genes in the PPI network. In conclusion, aberrant serum exosomal miRNAs were associated with an altered risk of osteoporosis in menopausal females and may act as potential biomarkers for the prediction of risk of osteoporosis in menopausal females.

The lncRNA LINC00691Functions as a ceRNA for miRNA-1256 to Suppress Osteosarcoma by Regulating the Expression of ST5

Introduction

Osteosarcoma is the most common primary malignant tumor in children and young patients. Although neoadjuvant chemotherapy and surgery could improve the prognosis of these patients, treatment outcomes are poor because of its low early diagnosis rate and high degree of malignancy as well as its tendency for early metastasis. In the field of osteosarcoma, lncRNAs have become a hot spot for studying the molecular mechanisms driving malignant biological characteristics and exploring effective treatment methods. An lncRNA is a long noncoding RNA lacking protein-encoding ability, and in its RNA form, it regulates various gene expression processes, such as epigenetic regulation, transcriptional regulation, and posttranscriptional regulation. LncRNAs play an important role in tumorigenesis and metastasis.

Methods

We used bioinformatics software to analyze the data in geo database. CCK-8 and Transwell were used to detect the effect of lncRNA LINC00691 on the proliferation and migration of osteosarcoma cells. The target gene of LINC00691 was detected by bioinformatics analysis and RNA pull down.

Results

In this study, we identified the lncRNA LINC00691 and confirmed its expression in osteosarcoma cells through GEO database analysis. Expression analysis showed that the levels of lncRNA LINC00691 in osteosarcoma cells were decreased compared to those of control cells. Overexpression of LINC00691 could inhibit the proliferation, migration, invasion, and induction of G1 cell cycle arrest in osteosarcoma cells, which was shown through in vitro and in vivo studies. Using bioinformatics analysis, RNA pull down experiments and luciferase reporter gene detection assays, we found that LINC00691 regulated ST5 expression by binding miR-1256. LINC00691 overexpression inhibited EMT by promoting the expression of E-cadherin and increasing the expression of ZEB1, Snail, and Fibronectin.

Conclusion

These results suggested that overexpressed LINC00691 promoted the expression of ST5 by regulating the function of miR-1256 through a ceRNA mechanism. The LINC00691/miR-1256/ST5 pathway plays an important role in the progression and metastasis of osteosarcoma and represents a good therapeutic target.

LncRNA, Important Player in Bone Development and Disease

BACKGROUND

Bone is an important tissue and its normal function requires tight coordination of transcriptional networks and signaling pathways, and many of these networks/ pathways are dysregulated in pathological conditions affecting cartilage and bones. Long non-coding RNA (lncRNA) refers to a class of RNAs with a length of more than 200 nucleotides, lack of protein-coding potential, and exhibiting a wide range of biological functions. Although studies on lcnRNAs are still in their infancy, they have emerged as critical players in bone biology and bone diseases. The functions and exact mechanism of bone-related lncRNAs have not been fully classified yet.

OBJECTIVE

The objective of this article is to summarize the current literature on lncRNAs on the basis of their role in bone biology and diseases, focusing on their emerging molecular mechanism, pathological implications and therapeutic potential.

DISCUSSION

A number of lncRNAs have been identified and shown to play important roles in multiple bone cells and bone disease. The function and mechanism of bone-related lncRNA remain to be elucidated.

CONCLUSION

At present, majority of knowledge is limited to cellular levels and less is known on how lncRNAs could potentially control the development and homeostasis of bone. In the present review, we highlight some lncRNAs in the field of bone biology and bone disease. We also delineate some lncRNAs that might have deep impacts on understanding bone diseases and providing new therapeutic strategies to treat these diseases.

Long non-coding maternally expressed gene 3 regulates cigarette smoke extract-induced apoptosis, inflammation and cytotoxicity by sponging miR-181a-2-3p in 16HBE cells

Accumulating evidence has suggested that long non-coding (lnc)RNAs are widely involved in the progression of multiple diseases, including chronic obstructive pulmonary disease (COPD). The aim of the present study was to explore the function and molecule mechanism of maternally expressed gene 3 (MEG3) in cigarette smoke extract (CSE)-treated 16HBE cells. Cell viability and apoptosis were evaluated using Cell Counting Kit-8 analysis and flow cytometry, respectively. Western blot analysis was carried out to determine the protein levels of Bcl-2, Bax and cleaved caspase-3. ELISA assays were utilized to measure the protein levels of IL-1β and IL-6 and TNF-α. Cytotoxicity was assessed using a lactate dehydrogenase release assay. The expression levels of MEG3 and microRNA (miR)-181a-2-3p were detected using reverse transcription-quantitative PCR. The interaction between miR-181a-2-3p and MEG3 was predicted using DIANA tools and verified by a dual-luciferase reporter assay and RNA Immunoprecipitation assay. MEG3 expression was enhanced while miR-181a-2-3p abundance was reduced in the serum of patients with COPD and CSE-treated 16HBE cells. MEG3-knockdown or miR-181a-2-3p-overexpression inhibited CSE-induced apoptosis, inflammation and cytotoxicity in 16HBE cells. Moreover, miR-181a-2-3p directly bind to MEG3 and its knockdown reversed the inhibitory effect of MEG3 interference on apoptosis, inflammation and cytotoxicity in CSE-treated 16HBE cells. Overall, MEG3-knockdown suppressed CSE-induced apoptosis, inflammation and cytotoxicity in 16HBE cells by upregulating miR-181a-2-3p, providing a promising therapeutic target for treatment of CSE-induced COPD.

The landscape of long non-coding RNAs in tumor stroma

AIMS

Long non-coding RNAs (lncRNAs) are associated with cancer development, while their relationship with the cancer-associated stromal components remains poorly understood. In this review, we performed a broad description of the functional landscape of stroma-associated lncRNAs in various cancers and their roles in regulating the tumor-stroma crosstalk.

MATERIALS AND METHODS

We carried out a systematic literature review of PubMed, Scopus, Medline, Bentham, and EMBASE (Elsevier) databases by using the keywords "LncRNAs in cancer," "LncRNAs in tumor stroma," "stroma," "cancer-associated stroma," "stroma in the tumor microenvironment," "tumor-stroma crosstalk," "drug resistance of stroma," and "stroma in immunosuppression" till July 2020. We collected the latest articles addressing the biological functions of stroma-associated lncRNAs in cancer.

KEY FINDINGS

These articles reported that dysregulated stroma-associated lncRNAs play significant roles in modulating the tumor microenvironment (TME) by the regulation of tumor-stroma crosstalk, epithelial to mesenchymal transition (EMT), endothelial to mesenchymal transition (EndMT), extracellular matrix (ECM) turnover, and tumor immunity.

SIGNIFICANCE

The tumor stroma is a substantial portion of the TME, and the dysregulation of tumor stroma-associated lncRNAs significantly contributes to cancer initiation, progression, angiogenesis, immune evasion, metastasis, and drug resistance. Thus, stroma-associated lncRNAs could be potentially useful targets for cancer therapy.

Long non-coding RNA MEG3 promotes cataractogenesis by upregulating TP53INP1 expression in age-related cataract

Age-related cataract (ARC) is the leading cause of visual impairment or even blindness among the aged population globally. Long non-coding RNA (LncRNA) has been proven to be the potential regulator of ARC. The latest study reveals that maternally expressed gene 3 (MEG3) promotes the apoptosis and inhibits the proliferation of multiple cancer cells. However, the expression and role of MEG3 in ARC are unclear. In this study, we investigated the effects of MEG3 in ARC and explored the regulatory mechanisms underlying these effects. We observed that MEG3 expression was up-regulated in the age-related cortical cataract (ARCC) lens capsules and positively correlated with the histological degree of ARCC. The pro-apoptosis protein, active caspase-3 and Bax increased in the anterior lens capsules of ARCC tissue, while the anti-apoptotic protein Bcl-2 decreased compared to normal lens. Knockdown of MEG3 increased the viability and inhibited the apoptosis of LECs upon the oxidative stress induced by H₂O₂. MEG3 was localized in both nucleus and cytoplasm in LECs. MEG3 facilitated TP53INP1 expression via acting as miR-223 sponge and promoting P53 expression. Additionally, TP53INP1 knockdown alleviated H₂O₂-induced lens turbidity. In summary, MEG3 promoted ARC progression by up-regulating TP53INP1 expression through suppressing miR-223 and promoting P53 expression, which would provide a novel insight into the pathogenesis of ARC.

LINC00662 Long Non-Coding RNA Knockdown Attenuates the Proliferation, Migration, and Invasion of Osteosarcoma Cells by Regulating the microRNA-15a-5p/Notch2 Axis

Purpose

Osteosarcoma (OS) is a frequently occurring malignancy in children and adolescents. In this study, we aimed to investigate the effects of the long non-coding RNA (lncRNA) LINC00662 (LINC00662) in OS and the underlying molecular mechanism.

Methods

The expression of LINC00662, microRNA-15a-5p (miR-15a-5p), and Notch2 in OS was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The proliferation, migration, and invasion of OS cells were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), wound-healing, and transwell assay. The interactions among LINC00662, miR-15a-5p, and Notch2 were determined by dual-luciferase reporter assays. A tumor xenograft model was established in mice for evaluating tumor growth in vivo.

Results

The expression of LINC00662 and Notch2 was found to be upregulated in OS, but the expression of miR-15a-5p was downregulated. The results demonstrated that LINC00662 knockdown attenuated the proliferation, migration, and invasion of OS cells and suppressed tumor growth in mice. The study further demonstrated that LINC00662 directly interacted with miR-15a-5p, and that Notch2 was a target of miR-15a-5p. The inhibition of miR-15a-5p or Notch2 overexpression markedly reversed the suppressive effect of sh-LINC00662 on the proliferation, migration, and invasion of OS cells.

Conclusion

The study demonstrated that LINC00662 could be a potential biomarker for OS therapy, and LINC00662 knockdown suppressed the proliferation, migration, and invasion of OS cells by regulating the miR-15a-5p/Notch2 axis.

Expression of ncRNAs on the DLK1-DIO3 Locus Is Associated With Basal and Mesenchymal Phenotype in Breast Epithelial Progenitor Cells

Epithelial-to-mesenchymal transition (EMT) and its reversed process mesenchymal-to-epithelial transition (MET) play a critical role in epithelial plasticity during development and cancer progression. Among important regulators of these cellular processes are non-coding RNAs (ncRNAs). The imprinted DLK1-DIO3 locus, containing numerous maternally expressed ncRNAs including the lncRNA maternally expressed gene 3 (MEG3) and a cluster of over 50 miRNAs, has been shown to be a modulator of stemness in embryonic stem cells and in cancer progression, potentially through the tumor suppressor role of MEG3. In this study we analyzed the expression pattern and functional role of ncRNAs from the DLK1-DIO3 locus in epithelial plasticity of the breast. We studied their expression in various cell types of breast tissue and revisit the role of the locus in EMT/MET using a breast epithelial progenitor cell line (D492) and its isogenic mesenchymal derivative (D492M). Marked upregulation of ncRNAs from the DLK1-DIO3 locus was seen after EMT induction in two cell line models of EMT. In addition, the expression of MEG3 and the maternally expressed ncRNAs was higher in stromal cells compared to epithelial cell types in primary breast tissue. We also show that expression of MEG3 is concomitant with the expression of the ncRNAs from the DLK1-DIO3 locus and its expression is therefore likely indicative of activation of all ncRNAs at the locus. MEG3 expression is correlated with stromal markers in normal tissue and breast cancer tissue and negatively correlated with the survival of breast cancer patients in two different cohorts. Overexpression of MEG3 using CRISPR activation in a breast epithelial cell line induced partial EMT and enriched for a basal-like phenotype. Conversely, knock down of MEG3 using CRISPR inhibition in a mesenchymal cell line reduced the mesenchymal and basal-like phenotype of the cell line. In summary our study shows that maternally expressed ncRNAs are markers of EMT and suggests that MEG3 is a novel regulator of EMT/MET in breast tissue. Nevertheless, further studies are needed to fully dissect the molecular pathways influenced by non-coding RNAs at the DLK1-DIO3 locus in breast tissue.

Long non-coding RNA MEG3 is involved in osteogenic differentiation and bone diseases (Review)

Osteogenic differentiation originating from mesenchymal stem cells (MSCs) requires tight co-ordination of transcriptional factors, signaling pathways and biomechanical cues. Dysregulation of such reciprocal networks may influence the proliferation and apoptosis of MSCs and osteoblasts, thereby impairing bone metabolism and homeostasis. An increasing number of studies have shown that long non-coding (lnc)RNAs are involved in osteogenic differentiation and thus serve an important role in the initiation, development, and progression of bone diseases such as tumors, osteoarthritis and osteoporosis. It has been reported that the lncRNA, maternally expressed gene 3 (MEG3), regulates osteogenic differentiation of multiple MSCs and also acts as a critical mediator in the development of bone formation and associated diseases. In the present review, the proposed mechanisms underlying the roles of MEG3 in osteogenic differentiation and its potential effects on bone diseases are discussed. These discussions may help elucidate the roles of MEG3 in osteogenic differentiation and highlight potential biomarkers and therapeutic targets for the treatment of bone diseases.

The Emerging Roles of Long Noncoding RNAs in Bone Homeostasis and Their Potential Application in Bone-Related Diseases

Increasing evidence has announced the emerging roles of long noncoding RNAs (lncRNAs) in modulating bone homeostasis due to their potential regulating effects on bone-related cells' proliferation, migration, differentiation and apoptosis. Thus, lncRNAs have been considered as a promising gene tool to facilitate the bone regeneration process and then to predict and cure bone-related diseases such as osteosarcoma, osteoporosis, and osteoarthritis. In this review, we first enumerated several kinds of dysregulated lncRNAs and concisely summarized their regulating role in bone formation as well as resorption process. The related mechanisms were also discussed, respectively. Then, the positive or negative behavior of these lncRNAs in bone-related diseases was elucidated. This review provides an in-depth sight about the lncRNA's clinical values and limitations, which is conducive to explore new gene targets and further establish new therapeutic strategies for bone-related disease.

The multiple function of long noncoding RNAs in osteosarcoma progression, drug resistance and prognosis

Osteosarcoma is a bone tumor prevalent in children and young adults. LncRNAs are a family of non-protein-coding transcripts longer than 200 nucleotides. The tumor-related pathological functions of lncRNAs include proliferation, migration, and chemotherapy resistance, all of which have been widely acknowledged in research on osteosarcoma. In addition, compelling evidence suggests that lncRNAs could serve as diagnostic indicators, prognostic biomarkers, and targets for disease treatment. In this review, we systematically summarize how lncRNAs regulate tumorigenesis, invasion and therapeutic resistance. By deepening our knowledge of the relationship between lncRNAs and osteosarcoma, we hope to translate research findings into clinical applications as soon as possible.

Long Noncoding RNA (lncRNA) Maternally Expressed Gene 3 (MEG3) Participates in Chronic Obstructive Pulmonary Disease through Regulating Human Pulmonary Microvascular Endothelial Cell Apoptosis

BACKGROUND Chronic obstructive pulmonary disease (COPD), a general airway disease, is featured by progressive and chronic immunoreaction in the lung. Increasing evidences have showed that cigarette smoking is the main reason in the COPD progression, and human pulmonary microvascular endothelial cell (HPMEC) apoptosis often be observed in COPD, while its pathogenesis is not yet fully described. Upregulation of long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) was observed in COPD patients, but the specific mechanism of lncRNA MEG3 in COPD remains unknown. The objective of this research was to explore the role of lncRNA MEG3 in cigarette smoke extract (CSE)-induced HPMECs. MATERIAL AND METHODS HPMECs were induced by a series of concentrations of CSE (0%, 0.1%, 1%, and 10%). Then cell apoptosis was analyzed by flow cytometry. Cell apoptosis related proteins were tested using western blot assay. Finally, we applied knockdown and over-expression system to explore the lncRNA MEG3 functions in CSE-induced HPMECs. RESULTS Our results indicated that various concentrations of CSE (0%, 0.1%, 1%, and 10%) significantly promoted cell apoptosis, augmented caspase-3 activity, upregulated Bax expression, decreased Bcl-2 expression, and enhanced lncRNA MEG3 level in HPMECs. LncRNA MEG3-plasmid transfection resulted in the upregulation of lncRNA MEG3, more apoptotic HPMECs, and higher caspase-3 activity. While lncRNA MEG3 knockdown presented the opposite effects. Further investigation suggested that all the effects of CSE treatment on HPMECs were markedly reversed by lncRNA MEG3-shRNA (short hairpin RNA). CONCLUSIONS Our study illustrated a protective effect of lncRNA MEG3-shRNA on CSE-induced HPMECs, indicting lncRNA MEG3 can be a new therapeutic approach for COPD treatment.

Matrine Restrains Cell Growth and Metastasis by Up-Regulating LINC00472 in Bladder Carcinoma

Purpose

Bladder Carcinoma (BC) is a malignant carcinoma with a high incidence in masculinity. We preliminarily researched the efficacy and mechanism of matrine (MAT) in T24 and 5637 cells.

Patients and Methods

CCK-8, flow cytometry, migration and invasion means were adopted to detect cell viability, apoptosis, migratory and invasive potentials. Moreover, LINC00472 expression was changed via transfection assays and was tested by RT-qPCR. Western blot was used for investigating the levels of CyclinD1, p53, Bcl-2, Bax, pro-Caspase-3, Cleaved-Caspase-3, β-actin, programmed cell death protein 4 (PDCD4) and relate-proteins of cell pathways. Tumor volume and weight were tested via animal experiments.

Results

MAT could not affect the growth of SV-HUC-1 cell but MAT promoted tumor cell apoptosis but restrained viability, invasion and migration. Furthermore, LINC00472 was prominently low expressed in BC tissues. MAT positively regulated LINC00472 and transfection with si-00472 could partly reverse the efficacies of MAT. Moreover, MAT enhanced PDCD4 expression by up-regulating LINC00472. Besides, we discovered MAT elevated PTEN but restrained PI3K/AKT proteins. Finally, tumor volume and weight were declined by MAT in vivo via up-regulating LINC00472.

Conclusion

MAT restrained cell growth and metastasis but promoted PDCD4 expression by up-regulating LINC00472 via restraining PTEN/PI3K/AKT pathway in BC.

MEG3 is restored by schisandrin A and represses tumor growth in choriocarcinoma cells

Schisandrin A (SchA) has been reported as a multidrug resistance-reversing agent; however, its antitumor effects have been rarely reported. Consequently, we attempted to explore whether SchA per se possesses an antitumor property in choriocarcinoma JEG-3 and BeWo cells and its potential mechanisms. JEG-3, BeWo, and HTR-8/SVneo cells were stimulated with SchA at different concentrations (10-100 μM), and cellular viability was evaluated with Cell Counting Kit-8. After stimulation with SchA, proliferation, apoptosis, migration, and invasion were detected by bromodeoxyuridine assay, Annexin V-fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) method, and a Transwell system, in JEG-3 cells transfected with short hairpin-RNA for maternally expressed 3. Western blot was performed to quantify protein. MEG3 was examined by a quantitative reverse transcription-polymerase chain reaction. MEG3 was downregulated in choriocarcinoma tissues. SchA diminished cellular viability, decreased proliferative activity, inhibited migratory and invasive behaviors, and repressed phosphorylation of regulators of phosphatidylinositol 3 kinase/protein kinase B/nuclear factor κB (PI3K/AKT/NF-κB) signaling cascade in gestational choriocarcinoma cells. MEG3 was upregulated by SchA in JEG-3 and BeWo cells. SchA exhibited little suppressive effects in JEG-3 cells lacking MEG3. Besides, the phosphorylation of transducers was evoked in MEG3-silenced JEG-3 cells despite stimulation with SchA. SchA administration repressed the growth of JEG-3 and BeWo cells by upregulating MEG3. Besides, SchA blocked PI3K/AKT/NF-κB signal cascade by elevating MEG3.

MicroRNA-127 Inhibits the Progression of Melanoma by Downregulating Delta-Like Homologue 1

Objective

Melanoma is the most common form of skin cancer with low survival rate and poor prognosis. MicroRNAs (miRNAs) have been reported to play essential roles in progression of melanoma. However, the role and mechanism of miR-127 in the process of melanoma remain poorly understood.

Methods

The expressions of miR-127 and delta-like homologue 1 (DLK1) were measured in melanoma tissues and cells by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Cell proliferation and apoptosis were measured by MTT assay, flow cytometry, and Western blot. The interaction between miR-127 and DLK1 was investigated by bioinformatics analysis, luciferase activity assay, and RNA immunoprecipitation (RIP). Murine xenograft model was conducted to investigate the effect of miR-127 on tumor growth in vivo.

Results

miR-127 was inhibited and DLK1 mRNA was enhanced in melanoma tissues and cells. Low abundance of miR-127 in melanoma tissues predicted a poor prognosis and was associated with the malignant clinicopathological features. Overexpression of miR-127 inhibited cell proliferation and induced apoptosis in melanoma cells. Moreover, DLK1 was targeted by miR-127 and its restoration reversed the regulatory effect of miR-127 on the process of melanoma. Besides, the addition of miR-127 suppressed xenograft tumor growth via suppressing DLK1 protein level in nude mice.

Conclusion

miR-127 blocked the development of melanoma by targeting DLK1, providing a novel biomarker for the treatment of melanoma.

miRNA signatures in childhood sarcomas and their clinical implications

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

Long non-coding RNA MEG3 knockdown attenuates endoplasmic reticulum stress-mediated apoptosis by targeting p53 following myocardial infarction

Mounting evidence has indicated that long non-coding RNA maternally expressed gene 3 (lncRNA MEG3) regulates cell apoptosis, and is involved in a variety of diseases. However, its exact role in myocardial infarction (MI) has not been fully elucidated. In the present study, we firstly observed that the expression levels of the lncRNA MEG3 in infarct hearts and hypoxic neonatal mice ventricular myocytes (NMVMs) were up-regulated by quantitative real-time PCR (qRT-PCR). Then, we knocked down lncRNA MEG3 by lentiviral delivery in the myocardial border region following multipoint injection. Following 28 days of MI, the lncRNA MEG3 knockdown mice indicated better cardiac function, and less cardiac remodelling by ultrasonic cardiogram and histological analysis. In addition, we indicated that lncRNA MEG3 knockdown reduced myocyte apoptosis and reactive oxygen species production in MI mice model and hypoxic NMVMs. Furthermore, we revealed that knockdown of lncRNA MEG3 protected against endoplasmic reticulum stress (ERS)-mediated myocardial apoptosis including the induction of PERK-eIF2α and caspase 12 pathways. At last, we provided evidence that p53 was identified as a protein target of lncRNA MEG3 to regulate NF-κB- and ERS-associated apoptosis. Taken collectively, our findings demonstrated that lncRNA MEG3 knockdown exerted cardioprotection by reducing ERS-mediated apoptosis through targeting p53 post-MI.

The role of long noncoding RNA in major human disease

BACKGROUND

Long noncoding RNAs (lncRNAs) are RNAs whose transcripts are longer than 200nt in length and lack the ability to encode proteins due to lack of specific open reading frames. lncRNAs were once thought to represent transcriptome noise or garbage sequences and a byproduct of RNA polymerase II (Pol II), and thereby ignored by researchers. In fact, lncRNA was involved in a wide variety of physiological and pathological processes in organisms. Comprehensive study of lncRNA does not only provide explanations to the physiological and pathological processes of living organisms, but also gives us new perspectives to the diagnosis, prevention and treatment of some clinical diseases. Therefore, the study of lncRNA is a very broad field of great research value and significance.

RESULTS

This article reviews the function of lncRNAs and their role in major human diseases.

CONCLUSIONS

Numerous studies show that lncRNA might serve as a biomarker for diagnosis and prognosis of various diseases. Compared to conventional biomarkers, lncRNA seems to have a higher diagnostic and prognostic values, not only because of their tissue and disease specific expression patterns, but also due to their highly stable physical and chemical properties.

Maternally expressed gene 3 (MEG3): A tumor suppressor long non coding RNA

Maternally expressed gene 3 (MEG3) is a long non-coding RNA (lncRNA) located on chromosome 14q32.3. Direct sequencing experiments have shown monoallelic expression of this lncRNA. Several studies have shown down-regulation of this lncRNA in human cancers. In some cases, hypermethylation of the promoter region has been suggested as the underlying mechanism. Functional studies have shown that this lncRNA controls expression of several tumor suppressor genes and oncogenes among them are p53, RB, MYC and TGF-β. Through regulation of Wnt-β-catenin pathway, it also affects epithelial-mesenchymal transition. In vitro studies have demonstrated contribution of MEG3 in defining response to chemotherapeutic agents such as paclitaxel, cisplatin and oxaliplatin. Certain polymorphisms within MEG3 are implicated in cancer risk (rs7158663, rs4081134 and rs11160608) or therapeutic response of cancer patients (rs10132552). Taken together, this lncRNA is regarded as a putative cancer biomarker and treatment target. In the current review, several aspects of the participation of MEG3 in carcinogenesis are discussed.

Identification of biomarkers associated with the recurrence of osteosarcoma using ceRNA regulatory network analysis

The aim of the present study was to identify the important mRNAs, micro (mi)RNAs and long non‑coding (lnc)RNAs that are associated with osteosarcoma recurrence. The GSE3905 dataset, which contains two sub‑datasets (GSE39040 and GSE39055), was downloaded from the Gene Expression Omnibus (GEO). Prognosis‑associated RNAs were identified by performing Cox regression univariate analysis and were subsequently used to construct a competing endogenous (ce)RNA regulatory network for Gene Set Enrichment Analysis (GSEA). Kaplan‑Meier survival analysis was used to determine the associations between expression levels and survival prognosis. In addition, another independent miRNA profile, GSE79181, was downloaded from GEO for validation. Among the differentially expressed RNAs, 417 RNAs (5 lncRNAs, 19 miRNAs, and 393 mRNAs) were observed to be associated with prognosis. The GSEA for the ceRNA regulatory network revealed that 'Mitogen‑activated protein kinase (MAPK) signaling pathway', 'Chemokine signaling pathway' and 'Spliceosome' were markedly associated with osteosarcoma. In addition, three lncRNAs [long intergenic non‑protein coding RNA 28 (LINC00028), LINC00323, and small nucleolar RNA host gene 1 (SNHG1)] and two miRNAs (hsa‑miR‑124 and hsa‑miR‑7) regulating three mRNAs [Ras‑related protein Rap‑1b (RAP1B), activating transcription factor 2 (ATF2) and protein phosphatase Mg2+/Mn2+ dependent 1B (PPM1B)] participated in the MAPK signaling pathway. The Kaplan‑Meier survival analysis also demonstrated that samples with lower expression levels of LINC00323 and SNHG1 had better prognosis, and samples with increased expression levels of LINC00028, hsa‑miR‑124 and hsa‑miR‑7 had better prognosis. Overexpression of RAP1B, ATF2 and PPM1B was positively associated with osteosarcoma recurrence. The roles of hsa‑miR‑124 and hsa‑miR‑7 in osteosarcoma recurrence were also validated using GSE79181. Thus, in conclusions, the three lncRNAs (LINC00028, LINC00323 and SNHG1), two miRNAs (hsa‑miR‑124 and hsa‑miR‑7) and three mRNAs (RAP1B, ATF2, and PPM1B) were associated with osteosarcoma recurrence.

MicroRNA-127-3p controls murine hematopoietic stem cell maintenance by limiting differentiation

The balance between self-renewal and differentiation is crucial to ensure the homeostasis of the hematopoietic system, and is a hallmark of hematopoietic stem cells. However, the underlying molecular pathways, including the role of micro-RNA, are not completely understood. To assess the contribution of micro-RNA, we performed micro-RNA profiling of hematopoietic stem cells and their immediate downstream progeny multi-potent progenitors from wild-type control and Pbx1-conditional knockout mice, whose stem cells display a profound self-renewal defect. Unsupervised hierarchical cluster analysis separated stem cells from multi-potent progenitors, suggesting that micro-RNA might regulate the first transition step in the adult hematopoietic development. Notably, Pbx1-deficient and wild-type cells clustered separately, linking micro-RNAs to self-renewal impairment. Differential expression analysis of micro-RNA in the physiological stem cell-to-multi-potent progenitor transition and in Pbx1-deficient stem cells compared to control stem cells revealed miR-127-3p as the most differentially expressed. Furthermore, miR-127-3p was strongly stem cell-specific, being quickly down-regulated upon differentiation and not re-expressed further downstream in the bone marrow hematopoietic hierarchy. Inhibition of miR-127-3p function in Lineage-negative cells, achieved through a lentiviral-sponge vector, led to severe stem cell depletion, as assessed with serial transplantation assays. miR-127-3p-sponged stem cells displayed accelerated differentiation, which was uncoupled from proliferation, accounting for the observed stem cell reduction. miR-127-3p overexpression in Lineage-negative cells did not alter stem cell pool size, but gave rise to lymphopenia, likely due to lack of miR-127-3p physiological downregulation beyond the stem cell stage. Thus, tight regulation of miR-127-3p is crucial to preserve the self-renewing stem cell pool and homeostasis of the hematopoietic system.

MEG3: an Oncogenic Long Non-coding RNA in Different Cancers

Long noncoding RNAs (lncRNAs) have recently considered as central regulators in diverse biological processes and emerged as vital players controlling tumorigenesis. Several lncRNAs can be classified into oncogenes and tumor suppressor genes depending on their function in cancer. A maternally expressed gene 3 (MEG3) gene transcripts a 1.6 kb lncRNA whose act as an antitumor component in different cancer cells, such as breast, liver, glioma, colorectal, cervical, gastric, lung, ovarian and osteosarcoma cancer cells. The present review highlights biological function of MEG3 to repress tumor through regulating the major tumor suppressor genes p53 and Rb, inhibiting angiogenesis-related factor, or controlling miRNAs. On the other hand, previous studies have also suggested that MEG3 mediates epithelial-mesenchymal transition (EMT). However, deregulation of MEG3 is associated with the  development and progression of cancer, suggesting that MEG3 may function as a potential biomarker and therapeutic target for human cancers.

LncRNA Meg3 protects endothelial function by regulating the DNA damage response

The role of long non-coding RNAs (lncRNAs) in regulating endothelial function through the DNA damage response (DDR) remains poorly understood. In this study, we demonstrate that lncRNA maternally expressed gene 3 (Meg3) interacts with the RNA binding protein polypyrimidine tract binding protein 3 (PTBP3) to regulate gene expression and endothelial function through p53 signaling ─ a major coordinator of apoptosis and cell proliferation triggered by the DDR. Meg3 expression is induced in endothelial cells (ECs) upon p53 activation. Meg3 silencing induces DNA damage, activates p53 signaling, increases the expression of p53 target genes, promotes EC apoptosis, and inhibits EC proliferation. Mechanistically, Meg3 silencing reduces the interaction of p53 with Mdm2, induces p53 expression, and promotes the association of p53 with the promoters of a subset of p53 target genes. PTBP3 silencing recapitulates the effects of Meg3 deficiency on the expression of p53 target genes, EC apoptosis and proliferation. The Meg3-dependent association of PTBP3 with the promoters of p53 target genes suggests that Meg3 and PTBP3 restrain p53 activation. Our studies reveal a novel role of Meg3 and PTBP3 in regulating p53 signaling and endothelial function, which may serve as novel targets for therapies to restore endothelial homeostasis.

SUMO protease SENP1 acts as a ceRNA for TGFBR2 and thus activates TGFBR2/Smad signaling responsible for LPS-induced sepsis

This study aims to explore the roles and related mechanisms of SUMO protease SENP1 in sepsis. Here, RNA-sequencing assay showed that SENP1 was significantly increased in human umbilical vein endothelial cells (HUVECs) with LPS treatment. Gene set enrichment analysis (GSEA) of RNA-sequencing dataset revealed that a positive enrichment of inflammation signatures was observed in HUVECs with SENP1 3'UTR overexpression. Further functional annotation analysis revealed that SENP1 3'UTR overexpression was positively correlated with TGFBR2 signaling pathway. Mechanistically, TGFBR2 was identified as a ceRNA (competing endogenous RNA) target of SENP1 and the downstream effectors Smad2/3 were also overexpressed in HUVECs with SENP1 3'UTR overexpression. Injection of SENP1 siRNA following LPS treatment attenuated LPS-induced sepsis, evidenced by the downregulation of IL-2 and TNF-α secretion and prolonged the overall survival of septic mice. Consistent results were obtained in vitro. Additionally, TGFBR2 overexpression partially abrogated SENP1 siRNA-mediated inhibition on LPS-induced sepsis. Thus, these results suggest that SENP1 promotes sepsis via activating the TGFBR2 signaling.

Non-Coding RNAs in Breast Cancer: Intracellular and Intercellular Communication

Non-coding RNAs (ncRNAs) are regulators of intracellular and intercellular signaling in breast cancer. ncRNAs modulate intracellular signaling to control diverse cellular processes, including levels and activity of estrogen receptor α (ERα), proliferation, invasion, migration, apoptosis, and stemness. In addition, ncRNAs can be packaged into exosomes to provide intercellular communication by the transmission of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) to cells locally or systemically. This review provides an overview of the biogenesis and roles of ncRNAs: small nucleolar RNA (snRNA), circular RNAs (circRNAs), PIWI-interacting RNAs (piRNAs), miRNAs, and lncRNAs in breast cancer. Since more is known about the miRNAs and lncRNAs that are expressed in breast tumors, their established targets as oncogenic drivers and tumor suppressors will be reviewed. The focus is on miRNAs and lncRNAs identified in breast tumors, since a number of ncRNAs identified in breast cancer cells are not dysregulated in breast tumors. The identity and putative function of selected lncRNAs increased: nuclear paraspeckle assembly transcript 1 (NEAT1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), steroid receptor RNA activator 1 (SRA1), colon cancer associated transcript 2 (CCAT2), colorectal neoplasia differentially expressed (CRNDE), myocardial infarction associated transcript (MIAT), and long intergenic non-protein coding RNA, Regulator of Reprogramming (LINC-ROR); and decreased levels of maternally-expressed 3 (MEG3) in breast tumors have been observed as well. miRNAs and lncRNAs are considered targets of therapeutic intervention in breast cancer, but further work is needed to bring the promise of regulating their activities to clinical use.

Astragalus polysaccharides decrease proliferation, migration, and invasion but increase apoptosis of human osteosarcoma cells by up-regulation of microRNA-133a

Osteosarcoma (OS) has a high incidence, malignity, and frequency of recurrence and metastasis. In this study, we aimed to explore the potential anti-cancer effects of Astragalus polysaccharides (APS) on human OS MG63 cells as well as underlying mechanisms. Viability of MG63 cells was assessed by CCK-8 assay to determine the adequate concentration of APS. Then, effects of APS on MG63 cell proliferation, cell cycle distribution, apoptosis, and migration and invasion were analyzed by BrdU incorporation, PI staining, flow cytometry, and transwell assays, respectively. The expression levels of proteins involved in these physiological processes were assessed by western blot analysis. Afterwards, miR-133a level in APS-treated cells was determined by qRT-PCR, and whether APS affected MG63 cells through regulation of miR-133a was determined. Finally, the activation of c-Jun N-terminal protein kinase (JNK) pathway was detected. We found that APS treatment suppressed the viability, proliferation, migration, and invasion of MG63 cells, as well as induced cell apoptosis. Moreover, APS enhanced the expression of miR-133a in MG63 cells. Knockdown of miR-133a reversed the APS treatment-induced MG63 cell proliferation, migration and invasion inhibition, as well as cell apoptosis. Furthermore, APS inactivated JNK pathway in MG63 cells. Knockdown of miR-133a reversed the APS treatment-induced inactivation of JNK pathway in MG63 cells. To conclude, APS repressed proliferation, migration, and invasion while induced apoptosis of OS MG63 cells by up-regulating miR-133a and then inactivating JNK pathway.

Geniposide suppresses growth, migration and invasion of MKN45 cells by down-regulation of lncRNA HULC

Gastric cancer (GC) is a serious disease with high incidence rate and high mortality. Geniposide (GEN) exhibits multiple biological properties including anti-tumor function. However, effect of GEN on GC is not well studied. Hence, the effects of GEN on GC were investigated in our study. HULC expression in GC tissue and GC cell lines (MKN45, SGC-7901, MKN28, AGS) was detected by qRT-PCR. Cell viability, colony formation, migration, invasion and cell apoptosis were examined by CCK-8 assay, survival fraction assay, modified two-chamber migration assay, Millicell Hanging Cell Culture and flow cytometry analysis, respectively. The expression of matrix metalloproteinase (MMP)-2/9 and vimentin was detected by qRT-PCR and western blot, respectively. The expression of PI3K/AKT and JNK was measured by western blot. The expression of HULC was up-regulated both in GC tissue and cell lines (P < .05, P < .01 or P < .001). GEN negatively regulated the expression of HULC in MKN45 cells (P < .05 or P < .01). GEN decreased cell viability (P < .05), colony formation (P < .01), migration (P < .05) and invasion (P < .05) while HULC overexpression led to the opposite results in GEN-treated cells. The expression of phosphatidylinositol 3' -kinase (PI3K)/ protein kinase B (AKT) and c-Jun N-terminal kinase (JNK) was down-regulated by GEN (all P < .05) while reversed by HULC overexpression. HULC was up-regulated in GC. GEN inhibited MNK45 cell viability, colony formation, migration and invasion while induced cell apoptosis by down-regulation of HULC in MKN45 cells. GEN inactivated PI3K/AKT and JNK signal pathways through down-regulation of HULC.

The Long Non-coding RNA MEG3/miR-let-7c-5p Axis Regulates Ethanol-Induced Hepatic Steatosis and Apoptosis by Targeting NLRC5

Ethanol (EtOH)-induced hepatic injury, characterized by hepatic steatosis with apoptosis, causes heavy health burden personally and socially. Long non-coding RNAs (lncRNAs) have been implicated in liver diseases. However, the role of lncRNA maternally expressed gene 3 (MEG3) in EtOH-induced hepatic injury remains unknown. The aim of present study was to assess the function of MEG3 and its functional interaction with miR-let-7c-5p in EtOH-induced hepatic injury. Here, we observed that MEG3 and NLRC5 expression was increased and miR-let-7c-5p expression decreased in EtOH-fed mice and EtOH-induced AML-12 cells. Knockdown of MEG3 contributed to attenuation of EtOH-induced steatosis and apoptosis in AML-12 cells. Also, expression level of MEG3 negatively correlated with miR-let-7c-5p expression and positively correlated with NLRC5 expression. In contrary to MEG3, miR-let-7c-5p overexpression attenuated EtOH-induced steatosis and apoptosis, as well as suppressed EtOH-induced increase in NLRC5 expression. By luciferase reporter assay, we concluded that miR-let-7c-5p directly binds to NLRC5 3′-UTR, thereby negatively regulates NLRC5 expression. Our data suggested that lncRNA MEG3 functions as a competing endogenous RNA for miR-let-7c-5p to regulate NLRC5 expression in EtOH-induced hepatic injury.

Potential applications of MEG3 in cancer diagnosis and prognosis

LncRNAs are emerging as integral functional and regulatory components of normal biological activities and are now considered as critically involved in the development of different diseases including cancer. In this review, we summarized recent findings on maternally expressed gene 3 (MEG3), a noncoding lncRNA, locates in the imprinted DLK1–MEG3 locus on human chromosome 14q32.3 region. MEG3 is expressed in normal tissues but is either lost or decreased in many human tumors and tumor derived cell lines. Studies have demonstrated that MEG3 is associated with cancer initiation, progression, metastasis and chemo-resistance. MEG3 may affect the activities of TP53, MDM2, GDF15, RB1 and some other key cell cycle regulators. In addition, the level of MEG3 showed good correlation with cancer clinicopathological grade. In summary, MEGs is an RNA-based tumor suppressor and is involved in the etiology, progression, and chemosensitivity of cancers. The alteration of MEG3 levels in various cancers suggested the possibility of using MEG3 level for cancer diagnosis and prognosis.