Downregulated LncRNA-ANCR promotes osteoblast differentiation by targeting EZH2 and regulating Runx2 expression

DANCR Promotes Metastasis and Proliferation in Bladder Cancer Cells by Enhancing IL-11-STAT3 Signaling and CCND1 Expression

The prognosis for patients with bladder cancer (BCa) with lymph node (LN) metastasis is poor, and it is not improved by current treatments. Long noncoding RNAs (lncRNAs) are involved in the pathology of various tumors, including BCa. However, the role of Differentiation antagonizing non-protein coding RNA (DANCR) in BCa LN metastasis remains unclear. In this study, we discover that DANCR was significantly upregulated in BCa tissues and cases with LN metastasis. DANCR expression was positively correlated with LN metastasis status, tumor stage, histological grade, and poor patient prognosis. Functional assays demonstrated that DANCR promoted BCa cell migration, invasion, and proliferation in vitro and enhanced tumor LN metastasis and growth in vivo. Mechanistic investigations revealed that DANCR activated IL-11-STAT3 signaling and increased cyclin D1 and PLAU expression via guiding leucine-rich pentatricopeptide repeat containing (LRPPRC) to stabilize mRNA. Moreover, oncogenesis facilitated by DANCR was attenuated by anti-IL-11 antibody or a STAT3 inhibitor (BP-1-102). In conclusion, our findings indicate that DANCR induces BCa LN metastasis and proliferation via an LRPPRC-mediated mRNA stabilization mechanism. DANCR may serve as a multi-potency target for clinical intervention in LN-metastatic BCa.

Effect of psoralen on the expression of PPARγ, osteocalcin, and trabecular bone area in rabbits with steroid-induced avascular necrosis of the femoral head

Objective

Psoralen is a natural plant toxin which has the function of protecting fungi, insects, and herbivores. In this study, we aim to investigate the effect and mechanism of psoralen on steroid-induced avascular necrosis of femoral head (SANFH).

Methods

Thirty rabbits were randomly divided into blank group (n = 10), model group (n = 10), and experimental group (n = 10). Rabbits in blank and model groups were treated with normal saline, and rabbits in experimental group were treated with psoralen. Total RNA of bone marrow was extracted by trizol, and the mRNA expression of PPARγ and osteocalcin were detected by q-PCR. Then, the mRNA expression of PPARγ and osteocalcin in the three groups were compared. Western blot was used to detect the PPARγ protein expression in the bone of rabbits. ELISA was used to measure the osteocalcin protein.

Results

The mRNA expression of PPARγ in model group significantly increased compared with blank group. The mRNA expression of osteocalcin in model group decreased compared with blank group. However, the mRNA and protein expressions of PPARγ in experimental group were significantly decreased compared with the model group. The protein expressions of osteocalcin increased compared with the model group. There was no significant difference of trabecular bone area (TBA) between experimental and blank groups (P > 0.05). TBA in model group was lower than the experimental group (P < 0.05). There was no significant difference of TBA between experimental and blank groups (P > 0.05).

Conclusion

This research confirms that psoralen plays a positive role in the rehabilitation of SANFH.

Long Noncoding RNAs: New Players in the Osteogenic Differentiation of Bone Marrow- and Adipose-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) are an important population of multipotent stem cells that differentiate into multiple lineages and display great potential in bone regeneration and repair. Although the role of protein-coding genes in the osteogenic differentiation of MSCs has been extensively studied, the functions of noncoding RNAs in the osteogenic differentiation of MSCs are unclear. The recent application of next-generation sequencing to MSC transcriptomes has revealed that long noncoding RNAs (lncRNAs) are associated with the osteogenic differentiation of MSCs. LncRNAs are a class of non-coding transcripts of more than 200 nucleotides in length. Noncoding RNAs are thought to play a key role in osteoblast differentiation through various regulatory mechanisms including chromatin modification, transcription factor binding, competent endogenous mechanism, and other post-transcriptional mechanisms. Here, we review the roles of lncRNAs in the osteogenic differentiation of bone marrow- and adipose-derived stem cells and provide a theoretical foundation for future research.

LncRNA HOXA-AS2 positively regulates osteogenesis of mesenchymal stem cells through inactivating NF-κB signalling

As is previously reported, mesenchymal stem cells have potential ability to differentiate into osteocytes. However, the underlying mechanism during this biological process is poorly understood. In the present study, we identify a novel long non-coding RNA named HOXA-AS2 as a critical regulator during the formation of osteogenesis. Attenuation of HOXA-AS2 can reduce the calcium deposition and repress the alkaline phosphatase activity. Moreover, the expressions of osteogenic marker genes are markedly downregulated after HOXA-AS2 depletion. Mechanistically, we found HOXA-AS2 can regulate the transcriptional activity of NF-κB, a critical inhibitor of osteogenesis. More importantly, HOXA-AS2 knockdown could result in the transcriptional repression of the osteogenic master transcription factor SP7 by a NF-κB/HDAC2-coordinated H3K27 deacetylation mechanism. Based on these studies, we conclude that HOXA-AS2 may serve as a promising therapeutic target for bone tissue repair and regeneration in the near future.

LncRNA DANCR upregulates PI3K/AKT signaling through activating serine phosphorylation of RXRA

Conventional therapies and novel molecular targeted therapies against breast cancer have gained great advances over the past two decades. However, poor prognosis and low survival rate are far from expectation for improvement, particularly in patients with triple negative breast cancer (TNBC). Here, we found that lncRNA DANCR was significantly overregulated in TNBC tissues and cell lines compared with normal breast tissues or other type of breast cancer. Knockdown of DANCR suppressed TNBC proliferation both in vitro and in vivo. Further study of underlying mechanisms demonstrated that DANCR bound with RXRA and increased its serine 49/78 phosphorylation via GSK3β, resulting in activating PIK3CA transcription, and subsequently enhanced PI3K/AKT signaling and TNBC tumorigenesis. Taken together, Our findings identified DANCR as an pro-oncogene and uncoverd a new working pattern of lncRNA to mediate TNBC tumorigenesis, which may be a potential therapeutic target for improving treatment of TNBC.

Regulation of osteogenesis by long noncoding RNAs: An epigenetic mechanism contributing to bone formation

Long noncoding RNAs (lncRNAs) have recently emerged as novel regulators of lineage commitment, differentiation, development, viability, and disease progression. Few studies have examined their role in osteogenesis; however, given their critical and wide-ranging roles in other tissues, lncRNAs are most likely vital regulators of osteogenesis. In this study, we extensively characterized lncRNA expression in mesenchymal cells during commitment and differentiation to the osteoblast lineage using a whole transcriptome sequencing approach (RNA-Seq). Using mouse primary mesenchymal stromal cells (mMSC), we identified 1438 annotated lncRNAs expressed during MSC differentiation, 462 of which are differentially expressed. We performed guilt-by-association analysis using lncRNA and mRNA expression profiles to identify lncRNAs influencing MSC commitment and differentiation. These findings open novel dimensions for exploring lncRNAs in regulating normal bone formation and in skeletal disorders.

LncRNA ANCR promotes proliferation and radiation resistance of nasopharyngeal carcinoma by inhibiting PTEN expression

Introduction

Antidifferentiation noncoding RNA (ANCR) is a newly identified long noncoding RNA, which is reported to function as an oncogene in multiple human cancers. However, its function in nasopharyngeal carcinoma (NPC) and underlying mechanism are still unclear.

Materials and methods

We explored the expression of ANCR in NPC tissues and cells by real-time PCR and analyzed the relationship between ANCR expression and clinicopathological characteristics of NPC patients by Pearson's chi-squared test. Then we inhibited ANCR expression in NPC cells using siRNAs and evaluated the effect of ANCR expression on cell proliferation, colony formation, and radiosensitivity by cell counting kit-8 assay and colony formation assay. We used RT-PCR and Western blot analyses to search target genes of ANCR. Also, we used RNA immunoprecipitation (RIP) assay and chromatin immunoprecipitation assay to study the molecular mechanism in this regulation.

Results

We found that ANCR was upregulated in NPC tissues and cells. ANCR expression was significantly correlated with tumor size and TNM stage. Further, ANCR knockdown inhibited NPC cell growth and radiation resistance. Mechanistically, we found that PTEN was upregulated in ANCR knockdown NPC cells. In addition, RIP assay indicated that EZH2, the oncogenic histone methyltransferase of polycomb repressive complex 2, interacted with ANCR in NPC cells. More importantly, the binding of EZH2 and deposition of relevant negative histone marker H3K27me3 on PTEN promoter depended on ANCR expression.

Conclusion

ANCR expression is upregulated in NPC and promotes NPC growth and radiation resistance through an epigenetic regulation of PTEN expression.

Potential functions of long non‑coding RNAs in the osteogenic differentiation of human bone marrow mesenchymal stem cells

Long non-coding RNAs (lncRNAs) are a specific group of RNA molecules that do not encode proteins. They have been shown to serve important regulatory functions in various biological and cell differentiation processes. However, the potential functions and regulatory mechanisms of lncRNAs that are associated with the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) remain to be elucidated. The present study aimed to investigate lncRNAs that are differentially expressed during the osteogenic differentiation of hBMSCs, along with the potential functions of those lncRNAs. To this end, three groups of hBMSCs were stimulated to undergo osteogenic differentiation for 7 days. Known lncRNAs, unknown lncRNAs and mRNAs that demonstrated differential expression prior to and following the osteogenic differentiation of hBMSCs were screened using lncRNA high-throughput sequencing. In addition, 12 lncRNAs were selected for reverse transcription-quantitative polymerase chain reaction (RT-qPCR) validation of the accuracy of the sequencing results. The potential functions and possible targets of the differentially expressed lncRNAs were analyzed using bioinformatics technologies (gene ontology, Kyoto Encyclopedia of Genes and Genomes and gene co-expression network analysis). In total, 64 lncRNAs were differentially expressed by at least two-fold in hBMSCs prior to and following osteogenic differentiation; these included seven known lncRNAs (two upregulated and five downregulated lncRNAs) and 57 unknown lncRNAs (35 upregulated and 22 downregulated lncRNAs). In addition, 409 mRNAs (257 upregulated and 152 downregulated mRNAs) were differentially expressed by at least two-fold. The RT-qPCR results obtained for 12 selected differentially expressed lncRNAs were consistent with the sequencing results. The gene co-expression network analysis of lncRNAs and mRNAs demonstrated that four lncRNAs (ENSG00000238042, lnc_1269, lnc_1369 and lnc_1708) may serve important roles in the osteogenic differentiation of hBMSCs. In conclusion, during the osteogenic differentiation of hBMSCs, the lncRNA expression profile changed significantly; certain of the observed differentially expressed lncRNAs may be derived from protein-coding genes and may serve important roles in osteogenic differentiation.

LncRNA TSIX promotes osteoblast apoptosis in particle-induced osteolysis by down-regulating miR-30a-5p

OBJECTIVE

This study aims to investigate the role of TSIX/miR-30a-5p axis in particle-induced osteolysis (PIO).

METHOD

PIO mouse model was established by the implantation of Co-Cr-Mo metal particles (CoPs). MC3T3-E1 cells received CoPs stimulation. Bone mineral density (BMD) in the skull was detected to evaluate PIO development. The expression of TSIX and miR-30a-5p was detected by using qRT-PCR. Osteoblast apoptosis was measured using flow cytometry. RNA pull-down was used to verify the regulatory relationship between TSIX and miR-30a-5p.

RESULT

The results showed that BMD of the skull in PIO mice was significantly decreased compared with control mice, which indicated that the PIO model was established successfully. Moreover, CoPs could up-regulate TSIX level, down-regulate miR-30a-5p expression, and promote osteoblast apoptosis in vivo and in vitro. The results also found that TSIX negatively regulated miR-30a-5p expression, and knockdown of TSIX inhibited Runx2 expression. As expected, miR-30a-5p inhibitor could reverse the inhibition of si-TSIX on osteoblast apoptosis.

CONCLUSION

TSIX played a pivotal role in PIO development by negatively regulating miR-30a-5p.

Genome-wide association study of lncRNA polymorphisms with bone mineral density

Recent studies suggested that long noncoding RNAs (lncRNAs) were widely transcribed in the genome, but their potential roles in the genetic complexity of human disorders required further exploration. The purpose of the present study was to explore genetic polymorphisms of lncRNAs associated with bone mineral density (BMD) and its potential value. Based on the lncRNASNP database, 55,906 lncSNPs were selected to conduct a genome-wide association study meta-analysis among 11,140 individuals of seven independent studies for BMDs at femoral neck (FN), lumbar spine, and total hip (HIP). Promising results were replicated in Genetic Factors for Osteoporosis Consortium (GEFOS Sequencing, n = 32,965). We found two lncRNA loci that were significantly associated with BMD. MEF2C antisense RNA 1 (MEF2C-AS1) located at 5q14.3 was significantly associated with FN-BMD after Bonferroni correction, and the strongest association signal was detected at rs6894139 (P = 3.03 × 10-9 ). LOC100506136 rs6465531 located at 7q21.3 showed significant association with HIP-BMD (P = 7.43 × 10-7 ). MEF2C-AS1 rs6894139 was replicated in GEFOS Sequencing with P-value of 1.43 × 10-23 . Our results illustrated the important role of polymorphisms in lncRNAs in determining variations of BMD and provided justification and evidence for subsequent functional studies.

Transcriptional profiling of murine osteoblast differentiation based on RNA-seq expression analyses

Osteoblastic differentiation is a multistep process characterized by osteogenic induction of mesenchymal stem cells, which then differentiate into proliferative pre-osteoblasts that produce copious amounts of extracellular matrix, followed by stiffening of the extracellular matrix, and matrix mineralization by hydroxylapatite deposition. Although these processes have been well characterized biologically, a detailed transcriptional analysis of murine primary calvaria osteoblast differentiation based on RNA sequencing (RNA-seq) analyses has not previously been reported. Here, we used RNA-seq to obtain expression values of 29,148 genes at four time points as murine primary calvaria osteoblasts differentiate in vitro until onset of mineralization was clearly detectable by microscopic inspection. Expression of marker genes confirmed osteogenic differentiation. We explored differential expression of 1386 protein-coding genes using unsupervised clustering and GO analyses. 100 differentially expressed lncRNAs were investigated by co-expression with protein-coding genes that are localized within the same topologically associated domain. Additionally, we monitored expression of 237 genes that are silent or active at distinct time points and compared differential exon usage. Our data represent an in-depth profiling of murine primary calvaria osteoblast differentiation by RNA-seq and contribute to our understanding of genetic regulation of this key process in osteoblast biology.

Pathological bases and clinical impact of long noncoding RNAs in prostate cancer: a new budding star

Long non-coding RNAs (lncRNAs) are functional RNAs longer than 200 nucleotides. Recent advances in the non-protein coding part of human genome analysis have discovered extensive transcription of large RNA transcripts that lack coding protein function, termed non-coding RNA (ncRNA). It is becoming evident that lncRNAs may be an important class of pervasive genes involved in carcinogenesis and metastasis. However, the biological and molecular mechanisms of lncRNAs in diverse diseases are not yet fully understood. Thus, it is anticipated that more efforts should be made to clarify the lncRNA world. Moreover, accumulating evidence has demonstrated that many lncRNAs are dysregulated in prostate cancer (PC) and closely related to tumorigenesis, metastasis, and prognosis or diagnosis. In this review, we will briefly outline the regulation and functional role of lncRNAs in PC. Finally, we discussed the potential of lncRNAs as prospective novel targets in PC treatment and biomarkers for PC diagnosis.

Long noncoding RNA ANCR suppresses bone formation of periodontal ligament stem cells via sponging miRNA-758

Long noncoding RNAs (lncRNAs) were proposed to be important regulators influencing various differentiation processes. Yet, the molecular mechanisms of lncRNAs governing osteogenic differentiation of Periodontal Ligament Stem Cells (PDLSCs) remain unclear. Here, PDLSCs were isolated from normal periodontal ligament of human (PDL) whereas P-PDLSCs were isolated from periodontitis affected PDL. Quantitative real-time PCR (qRT-PCR) was performed to examine the relative expression level of lncRNA-ANCR and of Osterix (OSX), Alkaline Phosphatase (ALP) as well as Runt-related transcription factor 2 (RUNX2) in PDLSCs. Gain- and loss-of- function experiments was performed to study the role of lncRNA-ANCR. Alizarin Red staining was used to evaluate the function of lncRNA-ANCR and miRNA-758 on osteogenic differentiation. In addition, via dual luciferase reporter assay and RNA immunoprecipitation the microRNA sponge potential of lncRNA-ANCR was assessed. A luciferase reporter assay identified the correlation between miR-758 and Notch2. Our results showed that the expression of ALP, RUNX2 and OSX were increased whereas lncRNA-ANCR was decreased during the process of differentiation in PDLSCs. Overexpression of lncRNA-ANCR decreased the expression of ALP, RUNX2 and OSX as confirmed by Alizarin red staining. Overexpression of lncRNA-ANCR resulted in reduction of the miR-758 expression level. Furthermore, RNA immunoprecipitation proved that lncRNA-ANCR targets miR-758 directly. The results of dual luciferase reporter assay also demonstrated that miR-758 regulated Notch2 expression by targeting 3'-UTR of Notch2. In conclusion, the novel pathway lncRNA-ANCR/miR-758/Notch2 plays an important role in the process of regulating osteogenic differentiation of PDLSCs.

Identification of a novel long noncoding RNA that promotes osteoblast differentiation

Long noncoding RNAs (lncRNAs) are a heterogeneous class of transcripts, longer than 200 nucleotides, 5'-capped, polyadenylated, and poorly conserved among mammalian species. Several studies have shown the contribution of lncRNAs to different cellular processes, including regulation of the chromatin structure, control of messenger RNA translation, regulation of gene transcription, regulation of embryonic pluripotency, and differentiation. Although limited numbers of functional lncRNAs have been identified so far, the immense regulatory potential of these RNAs is already evident, indicating that a functional characterization of lncRNAs is needed. In this study, mouse preosteoblastic cells were induced to differentiate into osteoblasts. At 3 sequential differentiation stages, total RNA was isolated and libraries were constructed for Illumina sequencing. The resulting sequences were aligned and transcript abundances were determined. New lncRNA candidates that displayed differential expression patterns during osteoblast differentiation were identified by combining bioinformatics and reverse transcription polymerase chain reaction analyses. Among these, lncRNA-1 that exhibited increased expression during osteogenesis and was downregulated during myogenesis. Importantly, knockdown of lncRNA-1 expression in primary mouse preosteoblasts was found to inhibit osteogenic differentiation, reflected by a reduced transcription of the Runx2/p57 and Sp7 bone master genes. Together, our results indicate that lncRNA-1 represents a new regulatory RNA that plays a relevant role during the early stages of osteogenesis.

The long non-coding RNA-DANCR exerts oncogenic functions in non-small cell lung cancer via miR-758-3p

Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in the occurrence and progression of multiple cancers. In this study, we investigated the role of the lncRNA DANCR in the development of non-small cell lung cancer (NSCLC). First, we found that DANCR was markedly upregulated in NSCLC tumor tissues and cell lines compared with related normal controls. The ectopic expression of DANCR significantly increased the proliferation, migration and invasion of SPC-A1 and NCL-H1299 cells. Furthermore, we investigated whether DANCR regulates NSCLC tumor formation in vivo. Subsequently, we concluded that DANCR promotes NSCLC cell proliferation, migration and invasion by regulating the tumor suppressor miR-758-3p. These results indicated that the DANCR/miR-758-3p axis could be a potential target in the treatment of NSCLC.

Lnc-NTF3-5 promotes osteogenic differentiation of maxillary sinus membrane stem cells via sponging miR-93-3p

BACKGROUND

The function and the mechanism of long non-coding RNAs (lncRNAs) on the osteogenic differentiation of maxillary sinus membrane stem cells (MSMSCs) remain largely unknown.

MATERIALS AND METHODS

The expression of lnc-NTF3-5 and Runt-related transcription factor 2 (RUNX2), Osterix (OSX), and Alkaline Phosphatase (ALP) was examined by quantitative real-time PCR (qRT-PCR) in MSMSCs during the process osteogenic differentiation. Then the function of lnc-NTF3-5 was evaluated by loss- and gain-of-function techniques, as well as qRT-PCR, western blot, and Alizarin Red staining. In addition, the microRNAs (miRNAs) sponge potential of lnc-NTF3-5 was assessed through RNA immunoprecipitation, dual luciferase reporter assay, and in vivo ectopic bone formation.

RESULTS

Lnc-NTF3-5, RUNX2, OSX, and ALP increased alone with the differentiation. Inhibition of lnc-NTF3-5 decreased the expression of RUNX2, OSX, and ALP both at mRNA and protein levels. Alizarin red staining showed similar trend. In contrast, overexpression of lnc-NTF3-5 presented totally opposite effects. Besides, overexpression of lnc-NTF3-5 could decrease the expression of microRNA-93-3p (miR-93-3p). Enhance miR-93-3p could also inhibit the expression level of lnc-NTF3-5. RNA immunoprecipitation demonstrated that lnc-NTF3-5 is directly bound to miR-93-3p and dual luciferase reporter assay proved that miR-93-3p targets 3' UTR of RUNX2 to regulate its expression. Ultimately, in vivo bone formation study showed that lnc-NTF3-5 and miR-93-3p inhibitor co-transfection group displayed the strongest bone formation.

CONCLUSIONS

The novel pathway lnc-NTF3-5/miR-93-3p/RUNX2 could regulate osteogenic differentiation of MSMSCs and might serve as a therapeutic target for bone regeneration in the posterior maxilla.

Differential Expression Profiling of Long Noncoding RNA and mRNA during Osteoblast Differentiation in Mouse

Long noncoding RNAs (lncRNAs) are emerging as an important controller affecting metabolic tissue development, signaling, and function. However, little is known about the function and profile of lncRNAs in osteoblastic differentiation in mice. Here, we analyzed the RNA-sequencing (RNA-Seq) datasets obtained for 18 days in two-day intervals from neonatal mouse calvarial pre-osteoblast-like cells. Over the course of osteoblast differentiation, 4058 mRNAs and 3948 lncRNAs were differentially expressed, and they were grouped into 12 clusters according to the expression pattern by fuzzy c-means clustering. Using weighted gene coexpression network analysis, we identified 9 modules related to the early differentiation stage (days 2–8) and 7 modules related to the late differentiation stage (days 10–18). Gene ontology and KEGG pathway enrichment analysis revealed that the mRNA and lncRNA upregulated in the late differentiation stage are highly associated with osteogenesis. We also identified 72 mRNA and 89 lncRNAs as potential markers including several novel markers for osteoblast differentiation and activation. Our findings provide a valuable resource for mouse lncRNA study and improves our understanding of the biology of osteoblastic differentiation in mice.

Long non-coding RNA HoxA-AS3 interacts with EZH2 to regulate lineage commitment of mesenchymal stem cells

Long non-coding RNAs (lncRNAs) play an important role in gene regulation and are involving in diverse cellular processes. However, their roles in reprogramming of gene expression profiles during lineage commitment and maturation of mesenchymal stem cells (MSCs) remain poorly understood. In the current study, we characterize the expression of a lncRNA, HoxA-AS3, during the differentiation of MSCs. We showed that HoxA-AS3 is increased upon adipogenic induction of MSCs, while HoxA-AS3 remains unaltered during osteogenic induction. Silencing of HoxA-AS3 in MSCs resulted in decreased adipogenesis and expression of adipogenic markers, PPARG, CEBPA, FABP4 and ADIPOQ. Conversely, knockdown of HoxA-AS3 expression in MSCs exhibited an enhanced osteogenesis and osteogenic markers expression, including RUNX2, SP7, COL1A1, IBSP, BGLAP and SPP1. Mechanistically, HoxA-AS3 interacts with Enhancer Of Zeste 2 (EZH2) and is required for H3 lysine-27 trimethylation (H3K27me3) of key osteogenic transcription factor Runx2. Our data reveal that HoxA-AS3 acts as an epigenetic switch that determines the lineage specification of MSC.

Linc-ROR Promotes Osteogenic Differentiation of Mesenchymal Stem Cells by Functioning as a Competing Endogenous RNA for miR-138 and miR-145

Long noncoding RNAs (lncRNAs), which serve as important and powerful regulators of various biological activities, have gained widespread attention in recent years. Emerging evidence has shown that some lncRNAs play important regulatory roles in osteoblast differentiation of mesenchymal stem cells (MSCs), suggesting a potential therapeutic strategy for bone fracture. As a recently identified lncRNA, linc-ROR was reported to mediate the reprogramming ability of differentiated cells into induced pluripotent stem cells (iPSCs) and human embryonic stem cells (ESCs) self-renewal. However, other functions of linc-ROR remain elusive. In this study, linc-ROR was found to be upregulated during osteogenesis of human bone-marrow-derived MSCs. Ectopic expression of linc-ROR significantly accelerated, whereas knockdown of linc-ROR suppressed, osteoblast differentiation. Using bioinformatic prediction and luciferase reporter assays, we demonstrated that linc-ROR functioned as a microRNA (miRNA) sponge for miR-138 and miR-145, both of which were negative regulators of osteogenesis. Further investigations revealed that linc-ROR antagonized the functions of these two miRNAs and led to the de-repression of their shared target ZEB2, which eventually activated Wnt/β-catenin pathway and hence potentiated osteogenesis. Taken together, linc-ROR modulated osteoblast differentiation by acting as a competing endogenous RNA (ceRNA), which may shed light on the functional characterization of lncRNAs in coordinating osteogenesis.

Anti-differentiation non-coding RNA, ANCR, is differentially expressed in different types of brain tumors

Long non-coding RNAs (lncRNAs) are important modulators of various cellular and molecular events, including cancer-associated pathways. The Anti-differentiation ncRNA (ANCR) is a key regulator of keratinocyte differentiation, where its expression is necessary to maintain epidermal progenitor's cells. Herein, we investigated the expression pattern of ANCR in the course of neural differentiation. Moreover, we used published RNAseq data and clinical samples to evaluate the alteration of ANCR expression in different cell types and brain tumors. Furthermore, we manipulated ANCR expression in glioma cell lines to clarify a potential functional role for ANCR in tumorigenesis. Our qRT-PCR results revealed a significant upregulation of ANCR in more malignant and less differentiated types of brain tumors (P = 0.03). This data was in accordance with down regulation of ANCR during neural differentiation. ANCR suppression caused an elevation in apoptosis rate, as well as a G1 cell cycle arrest in glioblastoma cell line. Altogether, our data demonstrated that ANCR may play a role in glioma genesis and that it could be considered as a potential diagnostic and therapeutic target to combat brain cancers.

lncRNA BANCR promotes EMT in PTC via the Raf/MEK/ERK signaling pathway

Thyroid cancer is one of the most common types of cancer in the endocrine system. Among all types of thyroid cancer, papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer. Long non-coding RNA (lncRNA) BRAF-activated non-protein-coding RNA (BANCR) is a 688-bp-long nucleotide transcript, which was first identified in melanoma. The function of BANCR in thyroid cancer remains unclear. The aim of the present study was to investigate whether BANCR is involved in the development of thyroid cancer. The results indicated that BANCR expression was increased in thyroid tumors compared with in adjacent normal tissues. Among cancer cell lines, the expression level of BANCR differed: BANCR expression in BCPAP cell lines was lower compared with that in CAL-62, WRO and FTC-133 cell lines. Overexpression of BANCR promoted the migration and invasion of BCPAP cells. Additionally, BANCR mediated epithelial-mesenchymal transition (EMT) by regulating the expression of epithelial (E)-cadherin, vimentin and neuronal (N)-cadherin. Overexpression of BANCR in BCPAP cells decreased the expression of E-cadherin and increased the expression of vimentin, N-cadherin, phospho (p)-c-Raf, p-extracellular-signal-regulated kinase (ERK)/mitogen activated protein kinase (MEK)1/2 and p-ERK1/2. Administration of U0126 inhibitor inhibited the regulation of phosphorylation levels by MEK1/2 and ERK1/2. Additionally, U0126 upregulated the expression of E-cadherin and downregulated the expression of vimentin. Taken together, the results of the present study suggest that BANCR induces EMT in PTC through the Raf/MEK/ERK signaling pathway.

Insights into the roles of lncRNAs in skeletal and dental diseases

Long noncoding RNAs (lncRNAs) are a class of non-protein-coding transcripts with the length longer than 200 nucleotides. Growing evidence suggests that lncRNAs, which were initially thought to be merely transcriptional “noise”, participate in a wide repertoire of biological processes. It has been well established that lncRNAs not only play important roles in genomic regulation, transcription, posttranscriptional processes but are also implicated in the pathogenesis of human diseases including cardiovascular diseases, diabetes, neurodegenerative disorders, and cancer. However, the pathological role of lncRNAs in skeletal and dental diseases is just beginning to be uncovered. In the present review, we outline the current understanding of the established functions and underlying mechanisms of lncRNAs in various cellular processes. Furthermore, we discuss new findings on the role of lncRNAs in osteoblastogenesis and osteoclastogenesis as well as their involvement in skeletal and dental diseases. This review intends to provide a general framework for the actions of lncRNAs and highlight the emerging evidence for the functions of lncRNAs in skeletal and dental diseases.

An Overview of Long Noncoding RNAs Involved in Bone Regeneration from Mesenchymal Stem Cells

Bone regeneration is very important for the recovery of some diseases including osteoporosis and bone fracture trauma. It is a multiple-step- and multiple-gene-involved complex process, including the matrix secretion and calcium mineralization by osteoblasts differentiated from mesenchymal stem cells (MSCs) and the absorption of calcium and phosphorus by osteoclasts differentiated from hematopoietic stem cells. Long noncoding RNAs (lncRNAs) are a family of transcripts longer than 200 nt without or with very low protein-coding potential. Recent studies have demonstrated that lncRNAs are widely involved in the regulation of lineage commitment and differentiation of stem cells through multiple mechanisms. In this review, we will summarize the roles and molecular mechanism of lncRNAs including H19, MALAT1, MODR, HOTAIR, DANCR, MEG3, HoxA-AS3, and MIAT in osteogenesis ossification; lncRNA ZBED3-AS1 and CTA-941F9.9, DANCR, and HIT in chondrogenic differentiation; and lncRNA DANCR in osteoclast differentiation. These findings will facilitate the development and application of novel molecular drugs which regulate the balance of bone formation and absorption.

EZH2-mediated suppression of lncRNA-LET promotes cell apoptosis and inhibits the proliferation of post-burn skin fibroblasts

Although the upregulation of enhancer of zeste homolog 2 (EZH2) expression and downregulation of long non-coding RNA (lncRNA) LET expression are known to be associated with cell apoptosis and proliferation, little is known about the interaction of EZH2 with lncRNA LET. The present study aimed to investigate the interaction of EZH2 and lncRNA LET, and the mechanism of human dermal fibroblast (HDF) proliferation and apoptosis. Tissue samples from 33 burn patients with second- and third-degree burns and 8 controls were collected. mRNA was extracted from the burn tissues for analysis. Isolated primary HDFs were treated with heat or transfected with LET overexpression vectors, and the cell functions and associated proteins in the HDFs were analyzed. Decreased lncRNA LET expression was detected in burn tissues compared with normal skin. Heat-treated HDFs exhibited a reduction in lncRNA LET expression and increase in EZH2 expression. LET gain-of-function experiments in primary HDFs revealed increases in cell proliferation, the proportion of cells in the S stage, and cyclin D1 and cyclin-dependent kinase 4 (CDK4) expression, and reductions in the percentage of apoptotic cells, the Bax/Bcl-2 ratio and caspase-3 expression. RNA immunoprecipitation and chromatin immunoprecipitation assays demonstrated the interaction of ZH2 with lncRNA LET, and of EZH2 with H3K27me3 in HDFs. Furthermore, a negative correlation between lncRNA LET and EZH2 expression was identified. It may be concluded that increased lncRNA-LET expression promoted cell proliferation and inhibited cell apoptosis via the cyclin D1-CDK4 and Bax/Bcl-2/caspase-3 signaling pathways, respectively. Furthermore, the inhibition of lncRNA LET may be regarded as an option for use in the healing of burns.

Long noncoding RNA DANCR promotes invasion of prostate cancer through epigenetically silencing expression of TIMP2/3

LncRNA DANCR suppresses differentiation of epithelial cells, however, its function in prostate cancer development is still unknown. In the present study, we found the expression of DANCR increases in prostate cancer tissues and cells compared to normal prostate tissues and cells, moreover, DANCR promotes invasion and migration of prostate cancer cells in vitro and metastasis of tumor xenografts in nude mice. Mechanistically, we found that TIMP2/3, which are critical metastasis inhibitor of prostate cancer, were down-regulated by DANCR synergistically with EZH2 through epigenetically silencing their promoter by chromatin immunoprecipitation assay. In addition, we further investigated whether DANCR is regulated by the differentiation-promoting androgen-androgen receptor (AR) pathway and found that DANCR expression is repressed by androgen-AR; furthermore, DANCR impedes the upregulation of TIMP2/3 and the suppression of invasion and migration by androgen-AR. On the other hand, interestingly, we found that in prostate cancer cells DANCR knockdown decreased the promotion of invasion and migration by the treatment of enzalutamide, which is an AR inhibitor. In summary, our results indicate that DANCR promotes prostate cancer invasion and metastasis through repressing the expression of TIMP2/3, and suggest that DANCR could be a potential target for preventing prostate cancer metastasis, and knockdown DANCR may lessen the potential side effect of AR inhibitor.

LncRNA DANCR involved osteolysis after total hip arthroplasty by regulating FOXO1 expression to inhibit osteoblast differentiation

Background

Aseptic loosening of artificial hip joint is a major complication affecting the long-term use of the artificial hip joint, and is the main cause of joint replacement failure. However, the mechanism of aseptic loosening of THR has not yet cleared. The aim of this study was to investigate the underlying mechanism of DANCR in osteoblast differentiation (OD).

Methods

We detected the expressions of DANCR and FOXO1 in clinical samples and mesenchymal stem cells (MSCs) by qRT-PCR and western blotting. The effects of polymethylmethacrylate (PMMA) on OD of MSCs were examined by alkaline phosphatase (ALP) activity and Alizarin Red S (ARS) staining. The expressions of OD markers were measured by qRT-PCR and western blotting. The mechanism of DANCR in OD was detected by RNA pull-down, RNA immunoprecipitation (RIP) assay and ubiquitination assays.

Results

Compared with the surrounding normal tissues, DANCR expression was up-regulated and FOXO1 expression was down-regulated in periprosthetic tissues. PMMA suppressed ALP activity, increased DANCR expression, and decreased the expressions of FOXO1, Runx2, Osterix (Ostx) and osteocalcin (OCN). ARS staining showed that PMMA inhibited the OD of MSCs. Knockdown of DANCR attenuated the inhibitory effect of PMMA on OD. Knockdown of FOXO1 could reverse the effect of si-DANC. RNA pull-down and RIP assay implicated that DANCR bound to FOXO1. Ubiquitination assay indicated that si-DANCR could repress Skp2-mediated ubiquitination of FOXO1.

Conclusion

LncRNA DANCR could inhibit OD by regulating FOXO1 expression.

The Potential Role of miRNAs as New Biomarkers for Osteoporosis

Osteoporosis is the most common metabolic bone disorder affecting up to 40% of postmenopausal women, characterized by a reduction in bone mass and strength leading to bone fragility and fractures. Despite the available tools for diagnosis and stratification of a fracture risk, bone loss occurs insidiously and osteoporosis is often diagnosed after the first fracture has occurred, with important health-related outcomes. Therefore, the need of markers that could efficiently diagnose bone fragility and osteoporosis is still necessary. Over the past few years, novel studies have focused on miRNAs, small noncoding RNAs that are differentially expressed in many pathological conditions, making them attractive biomarkers. To date, the role of miRNAs in bone disorders remains in great part unclear. In particular, limited and partly conflicting information is available concerning their use as potential biomarkers for osteoporosis, due to differences in patient selection, type of samples, and analytical methods. Despite these limits, concordant information about some specific miRNAs is now arising, making likely their use as additional tools to stratify the risk of osteoporosis and possibly fractures. In this review, we summarize the most relevant studies concerning circulating miRNAs differentially expressed in osteoporotic patients along with their function in bone cells and bone turnover.

Long Non-coding RNAs: A New Regulatory Code for Osteoporosis

Osteoporosis is a metabolic bone disease characterized by a decrease in bone mass and degradation of the bone microstructure, which increases bone fragility and fracture risk. However, the molecular mechanisms of osteoporosis remain unclear. Long non-coding RNAs (lncRNAs) have become important epigenetic regulators controlling the expression of genes and affecting multiple biological processes. Accumulating evidence of the involvement of lncRNAs in bone remolding has increased understanding of the molecular mechanisms underlying osteoporosis. This review aims to summarize recent progress in the elucidation of the role of lncRNAs in bone remodeling, and how it contributes to osteoblast and osteoclast function. This knowledge will facilitate the understanding of lncRNA roles in bone biology and shed new light on the modulation and potential treatment of osteoporosis.

Long non-coding RNA BDNF-AS modulates osteogenic differentiation of bone marrow-derived mesenchymal stem cells

For patients with osteoporosis, the inability of osteogenic differentiation is the key reason for bone loss. In this study, we investigated the expression and function of long non-coding RNA BDNF-AS in mesenchymal stem cell-derived osteogenic differentiation. Mouse bone marrow-derived mesenchymal stem cells (BMMSCs) were cultured in vitro and induced toward osteogenic differentiation. Quantitative real-time PCR (qRT-PCR) was used to evaluate gene expressions of BDNF-AS and BDNF during osteogenic differentiation. BMMSCs were also extracted from ovariectomized (OVX) mice. The dynamic change of BDNF-AS in OVX-derived BMMSCs during osteogenic differentiation was also evaluated. Lentivirus was used to upregulate BDNF-AS in BMMSCs. The effects of BDNF-AS upregulation on BMMSCs' proliferation and osteogenic differentiation were then evaluated. In addition, qRT-PCR and western blot were applied to further examine the effect of BDNF-AS upregulation on osteogenesis-associated signaling pathways, including BDNF, OPN, and Runx2, in osteogenic differentiation. BDNF-AS was downregulated, whereas BDNF was upregulated in osteogenic differentiation of BMMSCs. Among OVX-derived BMMSCs, BDNF-AS expression was upregulated during osteogenic differentiation. Lentivirus-induced BDNF-AS upregulation promoted BMMSCs self-proliferation but inhibited osteogenic differentiation, as demonstrated by proliferation, alizarin red staining, and alkaline phosphatase activity assays, respectively. QRT-PCR and western blot demonstrated that BDNF, OPN, and Runx2 were downregulated by BDNF-AS upregulation in the differentiated BMMSCs. BDNF-AS is dynamically regulated in osteogenic differentiation. Upregulating BDNF-AS inhibits osteogenesis, possibly through inverse regulation on BDNF and osteogenic signaling pathways.

MYC Targeted Long Noncoding RNA DANCR Promotes Cancer in Part by Reducing p21 Levels

The MYC oncogene broadly promotes transcription mediated by all nuclear RNA polymerases, thereby acting as a positive modifier of global gene expression. Here, we report that MYC stimulates the transcription of DANCR, a long noncoding RNA (lncRNA) that is widely overexpressed in human cancer. We identified DANCR through its overexpression in a transgenic model of MYC-induced lymphoma, but found that it was broadly upregulated in many human cancer cell lines and cancers, including most notably in prostate and ovarian cancers. Mechanistic investigations indicated that DANCR limited the expression of cell-cycle inhibitor p21 (CDKN1A) and that the inhibitory effects of DANCR loss on cell proliferation could be partially rescued by p21 silencing. In a xenograft model of human ovarian cancer, a nanoparticle-mediated siRNA strategy to target DANCR in vivo was sufficient to strongly inhibit tumor growth. Our observations expand knowledge of how MYC drives cancer cell proliferation by identifying DANCR as a critical lncRNA widely overexpressed in human cancers.Significance: These findings expand knowledge of how MYC drives cancer cell proliferation by identifying an oncogenic long noncoding RNA that is widely overexpressed in human cancers. Cancer Res; 78(1); 64-74. ©2017 AACR.

Long Non-coding RNA XIST Promotes Glioma Tumorigenicity and Angiogenesis by Acting as a Molecular Sponge of miR-429

Glioma is a worldwide malignancy, which displays significantly active metastasis and angiogenesis. Interaction between long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) has been shown to play crucial role in regulating tumor properties. However, the potential of lncRNA X-inactive specific transcript (XIST) to function as a miRNA regulator and its relevance in glioma tumorigenicity and angiogenesis have so far remained unclear. Expression analysis of lncRNA XIST in glioma cells revealed its significant up-regulation. Interestingly, silencing of XIST repressed both metastatic and pro-angiogenic ability in vitro as well as in vivo. Subsequent studies revealed that lncRNA XIST expression inversely correlated with miR-429 expression in glioma cells; miR-429 modulated XIST expression by directly targeting the XIST gene sequence. In addition, miR-429 inhibitor restored metastatic and pro-angiogenic ability of gliomas abolished by silencing XIST. Our data provide insight into the key roles of the lncRNA-miRNA functional network in gliomas, which can aid in developing new therapeutic strategies for gliomas through clinical trials.

Long non‑coding RNA DANCR regulates the proliferation and osteogenic differentiation of human bone-derived marrow mesenchymal stem cells via the p38 MAPK pathway

Long non-coding RNAs (lncRNAs) have been established to participate in the complex network of various biological processes and play important roles in the differentiation of mesenchymal stem cells (MSCs). However, the roles of lncRNAs in the mechanisms of the osteogenic differentiation of human bone marrow-derived MSCs (HBMSCs) are poorly understood. Thus, this study aimed to investigate the effects of the lncRNA, differentiation antagonizing non-protein coding RNA (DANCR), on the proliferation and osteogenic differentiation of HBMSCs. We found that lncRNA DANCR was abnormally decreased in HBMSCs during osteogenic differentiation. DANCR knockdown induced by transfection with siRNA targeting DANCR (si-DANCR) significantly enhanced the proliferation and osteogenic differentiation of HBMSCs. By contrast, when DANCR expression was enhanced by transfection with a DANCR overexpression vector (pcDNA-DANCR), the proliferation and osteogenic differentiation of the HBMSCs were markedly inhibited. We further found that mitogen-activated protein kinase (MAPK) pathways were involved in the DANCR-mediated proliferation and osteogenic differentiation of HBMSCs. Moreover, DANCR was found to mediate the proliferation and osteogenic differentiation of HBMSCs via p38 MAPK inactivation, but not via extracellular signal-regulated protein kinase (ERK)1/2 or c-Jun N-terminal kinase (JNK) MAPKs, but. Combination treatment (pcDNA-DANCR and with the p38 specific inhibitor, SB203580) led to synergistic inhibitory effects, and these inhibitory effects were reversed by DANCR knockdown. These findings not only provide a novel interpretation for the mechanisms of the proliferation and osteogenic differentiation of HBMSCs, but also suggest that DANCR may be a novel therapeutic target for bone-destructive diseases in the future.

Expression of long non‑coding RNAs in human bone marrow mesenchymal stem cells co‑cultured with human amnion‑derived mesenchymal stem cells

Long non-coding RNAs (lncRNAs) serve a critical role in various biological processes including cell growth, transcriptional regulation and differentiation. Previous studies have demonstrated that human amnion-derived mesenchymal stem cells (HAMSCs) possess the potential to promote proliferation and osteogenic differentiation of human bone marrow mesenchymal stem cells (HBMSCs). However, little is known about the roles of lncRNAs in these mechanisms. The present study investigated the expression of lncRNAs in HBMSCs co-cultured with HAMSCs to study their involvement in the mechanism of osteogenic differentiation. RNA sequencing was used to compare the lncRNA expression profiles of HBMSCs co-cultured with or without HAMSCs during osteogenic differentiation. A total of 339 differentially expressed lncRNAs were identified [log2 (fold change)>2.0 or <-2.0; P<0.05], consisting of 131 downregulated and 208 upregulated lncRNAs. Among these lncRNAs, it was identified that the lncRNA-differentiation antagonizing non-protein coding RNA (DANCR) expression level in HBMSCs was significantly decreased by co-culturing with HAMSCs, and DANCR overexpression inhibited the effect of HAMSCs on the promotion of runt-related transcription factor 2 expression. These data suggested that HAMSCs are likely to regulate differentiation processes in HBMSCs by influencing the DANCR, thus offering a novel insight into the complicated regulation mechanisms of HAMSC-derived osteogenic differentiation.

Long non-coding RNA DANCR, a prognostic indicator, promotes cell growth and tumorigenicity in gastric cancer

Gastric cancer remains the third leading cause of cancer-related mortality worldwide, and proliferation of gastric cancer represents the major reason for its poor prognosis. Recent evidence indicates that long non-coding RNAs play crucial roles in development and progression of gastric cancer. Long non-coding RNA differentiation antagonizing non-protein coding RNA is upregulated in hepatic cell carcinoma, but the role of lncRNA differentiation antagonizing non-protein coding RNA in gastric cancer has not been explored. In this article, we found that differentiation antagonizing non-protein coding RNA is also upregulated in gastric cancer. Experiments revealed that silencing differentiation antagonizing non-protein coding RNA significantly inhibited gastric cancer cell proliferation in vitro and in vivo. Overexpression of differentiation antagonizing non-protein coding RNA notably increases gastric cancer cell proliferation. From RNA-seq and gene ontology annotations, we found that differentiation antagonizing non-protein coding RNA influences the gene expression programs in cell metabolic and cycle process. Taken together, our findings suggest that the long non-coding RNA differentiation antagonizing non-protein coding RNA promotes the proliferation of gastric cancer and is a potential prognostic biomarker and therapeutic target in gastric cancer.

Ectopic expression of the transcription factor MafB in basal keratinocytes induces hyperproliferation and perturbs epidermal homeostasis

Mammalian epidermis is composed of four morphologically and functionally distinct layers of keratinocytes. The innermost basal layer consists of proliferating self-renewing keratinocytes, which also undergo asymmetric cell division to differentiate into postmitotic suprabasal cells throughout life. Control of the balance between growth and differentiation of basal cells is important for epidermal homeostasis to prevent skin disorders including malignancies; however, the underlying mechanism remains to be elucidated. Recently, MafB was identified as one of the transcription factors that regulate epidermal keratinocyte differentiation. MafB is expressed in postmitotic differentiating keratinocytes, and epidermal differentiation is partially impaired in MafB-deficient mice. To further establish the roles of MafB in the epidermis in vivo, we generated mice transgenic for MafB under the control of the basal cell-specific keratin (Krt) 14 promoter. In the epidermis of transgenic mice at embryonic day 18.5, the number of proliferating Krt14-positive basal-like cells was increased, and the granular and cornified layers were thickened. Furthermore, these MafB transgenic mice developed papillomas spontaneously with age. Therefore, MafB promotes differentiation in postmitotic keratinocytes and simultaneously has potential to promote growth when ectopically expressed in undifferentiated basal keratinocytes.

LncRNA ANCR down-regulation promotes TGF-β-induced EMT and metastasis in breast cancer

Epithelial to mesenchymal transition (EMT) is a progression of cellular plasticity critical for development, differentiation, cancer cells migration and tumor metastasis. As a well-studied factor, TGF-β participates in EMT and involves in physiological and pathological functions of tumor progression. Accumulating evidence indicates that long noncoding RNAs(lncRNAs) play crucial roles in EMT and tumor metastasis. Here, we find that lncRNA ANCR participates in TGF-β1-induced EMT. By our ChIP and Real-time PCR assays, we reveal that TGF-β1 down-regulates ANCR expression by increasing HDAC3 enrichment at ANCR promoter region, which decreases both H3 and H4 acetylation of ANCR promoter. In addition, by western blot and transwell assays, we indicate that ectopic expression of ANCR partly attenuates the TGF-β1-induced EMT. Downstream, ANCR inhibits breast cancer cell migration and breast cancer metastasis by decreasing RUNX2 expression in vitro and in vivo. Thus, our study identifies ANCR, as a new TGF-β downstream molecular, is essential for TGF-β1-induced EMT by decreasing RUNX2 expression. These results implicate that ANCR might become a prognostic biomarker and an anti-metastasis therapy target for breast cancer.

LncRNA MALAT1 sponges miR-204 to promote osteoblast differentiation of human aortic valve interstitial cells through up-regulating Smad4

BACKGROUND

Emerging evidences have indicated that long non-coding RNAs (lncRNAs) play vital roles in cardiovascular physiology and pathology. The lncRNA MALAT1, a highly abundant and conserved imprinted gene, has been implicated in many cardiovascular diseases. However, the function of MALAT1 in calcific aortic valve disease (CAVD) remains unknown. This study sought to document the function and underlying mechanism of MALAT1 in regulating CAVD.

METHODS

Protein level was determined by immunoblotting and immunofluorescence staining. MALAT1, miR-204 and mRNA expressions were detected by qRT-PCR. Mineralized bone matrix formation was assessed by Alizarin Red staining. The interaction between MALAT1 and miR-204 was studied using luciferase reporter assay, RNA pull-down assay and RNA-binding protein immunoprecipitation assay.

RESULTS

Ectopic expression of MALAT1 was observed in calcific valves and after osteogenic induction in human aortic valve interstitial cells (VICs). In vitro experiments revealed that MALAT1 acted as a positive regulator of osteogenic differentiation by repressing miR-204 expression and activity and thereby promoting expression of osteoblast-specific markers, including alkaline phosphatase, mineralized bone matrix formation and osteocalcin. Mechanistically, we identified Smad4 as a direct target of miR-204. Importantly, MALAT1 could directly interact with miR-204 and overexpression of miR-204 efficiently reversed the upregulation of Smad4 induced by MALAT1. Thus, MALAT1 positively regulated the expression of Smad4 through sponging miR-204, and promoted osteogenic differentiation of VICs.

CONCLUSIONS

Our study provides novel mechanistic insights into a critical role for lncRNA MALAT1 as a miRNA sponge in CAVD and sheds new light on lncRNA-directed diagnostics and therapeutics in CAVD.

Indirect effects of X-irradiation on proliferation and osteogenic potential of bone marrow mesenchymal stem cells in a local irradiated rat model

Cancer survivors after radiotherapy may suffer a variety of bone-related adverse side effects, including radioactive osteoporosis and fractures. Localized irradiation is a common treatment modality for malignancies. Recently, a series of reactions and injuries called indirect effects (remote changes in bone when other parts of the body are irradiated) have been reported on the indirect irradiated area of bone tissue after radiotherapy. To address this issue, we developed a rat localized irradiation model. Rats were irradiated with a single dose of X-rays to the left hind limbs, and bone marrow mesenchymal stem cells (BMMSCs) were isolated from bone marrow of the left (direct irradiated) and right (indirect irradiated) hind limbs 3, 7 and 14 days after irradiation, and assayed for the proliferation ability and osteogenic potential by alkaline phosphatase (ALP) activity, mineralization assay, RT-PCR and western blot analysis. The results showed that there were significant morphology changes in the BMMSCs from direct and indirect irradiated bone tissue with bigger cell bodies and increased granules. The proliferation of BMMSCs decreased both in the direct irradiated and non-irradiated bone tissue. The ALP expression and activities of BMMSCs from direct irradiated bone was consistently defected following a transient enhancement, the mRNA levels of RUNX2 and OCN, the protein expression of RUNX2, and the mineralization ability also showed the same trend. Simultaneously, in indirect irradiated group, the osteogenic potential indicators of BMMSCs decreased in the early stage of post-irradiation and were still impaired 14 days after irradiation. Our data demonstrate that localized irradiation may have both direct and indirect adverse effects on BMMSCs' proliferation and osteogenic potential into osteoblast, which may be the mechanism of radiation-induced abscopal impairment to the skeleton in the cancer radiotherapy-induced bone loss.

Epigenetic regulation of bone cells

Bone is a major organ in the skeletal system that supports and protects muscles and other organs, facilitates movement and hematopoiesis, and forms a reservoir of minerals including calcium. The cells in the bone, such as osteoblasts, osteoclasts, and osteocytes, orchestrate sequential and balanced regulatory mechanisms to maintain bone and are capable of differentiating in bones. Bone development and remodeling require a precise regulation of gene expressions in bone cells, a process governed by epigenetic mechanisms such as histone modification, DNA methylation, and chromatin structure. Importantly, lineage-specific transcription factors can determine the epigenetic regulation of bone cells. Emerging data suggest that perturbation of epigenetic programs can affect the function and activity of bone cells and contributes to pathogenesis of bone diseases, including osteoporosis. Thus, understanding epigenetic regulations in bone cells would be important for early diagnosis and future therapeutic approaches.

LncRNA-ANCR down-regulation suppresses invasion and migration of colorectal cancer cells by regulating EZH2 expression

Our study aimed to explore the effects of long noncoding RNA (lncRNA)-ANCR on the invasion and migration of colorectal cancer (CRC) cells by regulating enhancer of zeste homolog 2 (EZH2) expression. CRC tissues and adjacent normal tissues were collected and CRC SW620 cells line and normal human intestinal epithelial cells (HIECs) were incubated. CRC SW620 cells line was transfected with ANCR-siRNA. The expressions of ANCR and EZH2 mRNA were measured by real-time quantitative polymerase chain reaction (RT-qPCR). EZH2 and trimethylation of H3K27 (H3K27me3) protein expressions were detected using Western blotting. The relationship between ANCR and EZH2 was determined through RNA pull-down and co-immunoprecipitation (co-IP) assays. Cell invasion and migration were determined by Trans-well and cell scratch assays. ANCR, EZH2 and H3K27me3 expressions were up-regulated in CRC tissues and SW620 cells (all P < 0.05). After transfected with ANCR-siRNA, SW620 cells showed decreased ANCR expression and EZH2 mRNA and protein expressions (all P < 0.05). According to the results of RNA pull-down and co-IP assays, ANCR could specifically bind to EZH2. The results of Trans-well and cell scratch tests showed that when ANCR expression was decreased, the invasion and migration abilities of SW620 cells significantly declined (both P < 0.05). In conclusion, these results suggest that lncRNA-ANCR could influence the invasion and migration of CRC cells by specifically binding to EZH2.

Emerging roles for long noncoding RNAs in skeletal biology and disease

Normal skeletal development requires tight coordination of transcriptional networks, signaling pathways, and biomechanical cues, and many of these pathways are dysregulated in pathological conditions affecting cartilage and bone. Recently, a significant role has been identified for long noncoding RNAs (lncRNAs) in developing and maintaining cellular phenotypes, and improvements in sequencing technologies have led to the identification of thousands of lncRNAs across diverse cell types, including the cells within cartilage and bone. It is clear that lncRNAs play critical roles in regulating gene expression. For example, they can function as epigenetic regulators in the nucleus via chromatin modulation to control gene transcription, or in the cytoplasm, where they can function as scaffolds for protein-binding partners or modulate the activity of other coding and noncoding RNAs. In this review, we discuss the growing list of lncRNAs involved in normal development and/or homeostasis of the skeletal system, the potential mechanisms by which these lncRNAs might function, and recent improvements in the methodologies available to study lncRNA functions in vitro and in vivo. Finally, we address the likely utility of lncRNAs as biomarkers and therapeutic targets for diseases of the skeletal system, including osteoarthritis, osteoporosis, and in cancers of the skeletal system.

Antidifferentiation Noncoding RNA Regulates the Proliferation of Osteosarcoma Cells

BACKGROUND

Antidifferentiation noncoding RNA (ANCR), a newly identified long noncoding RNA (lncRNA), plays a critical role for stem cells to maintain undifferentiated cell state. However, the functions of ANCR in human cancers have not been reported. This study is designed to explore the role of ANCR in osteosarcoma.

METHODS

Lentivirus-mediated (shRNA) was applied to silence ANCR in the human osteosarcoma cell lines U2OS and Saos-2. Cell viability was measured by MTT assay. Colony-forming ability was measured by colony formation assay. Cell cycle progression was determined by flow cytometry with propidium iodide staining. In addition, cell cycle makers, including p21, CDK2, and CDK4, were investigated in ANCR silencing U2OS cells by real time PCR (RT-PCR) analysis.

RESULTS

In this study, we first proved that lentivirus-mediated shRNA specifically suppressed the expression level of ANCR in U2OS and Saos-2 cells. Further investigations revealed that knockdown of ANCR significantly inhibited the proliferation of U2OS and Saos cells and colony formation of U2OS cells. Moreover, the cell cycle of U2OS cells was arrested at G0/G1 phase after ANCR knockdown. Furthermore, the expression level of p21 was increased and CDK2 was decreased in ANCR knock-down cells.

CONCLUSIONS

Our data indicated that ANCR might be an oncogenic lncRNA that promoted proliferation of osteosarcoma. The potential application of ANCR-targeted therapy using the lentivirus-mediated shRNA approach is worth further investigations in preclinical and clinical studies.

Long noncoding RNA H19 accelerates tenogenic differentiation and promotes tendon healing through targeting miR-29b-3p and activating TGF-β1 signaling

Tendon injures are common orthopedic conditions, but tendon development and the pathogenesis of tendon injures, such as tendinopathy, remain largely unknown and have limited the development of clinical therapy. Studies on tenogenic differentiation at the molecular level may help in developing novel therapeutic strategies. As novel regulators, long noncoding RNAs (lncRNAs) have been found to have widespread biological functions, and emerging evidence demonstrates that lncRNAs may play important regulatory roles in cell differentiation and tissue regeneration. In this study, we found that lncRNA H19 stimulated tenogenesis of human tendon-derived stem cells. Stable overexpression of H19 significantly accelerated TGF-β1-induced tenogenic differentiation in vitro and accelerated tendon healing in a mouse tendon defect model. H19 directly targeted miR-29b-3p, which is considered to be a negative regulator of tenogenesis. Furthermore, miR-29b-3p directly suppressed the expression of TGF-β1 and type I collagen, thereby forming a novel regulatory feedback loop between H19 and TGF-β1 to mediate tenogenic differentiation. Our study demonstrated that H19 promotes tenogenic differentiation both in vitro and in vivo by targeting miR-29b-3p and activating TGF-β1 signaling. Regulation of the TGF-β1/H19/miR-29b-3p regulatory loop may be a new strategy for treating tendon injury.-Lu, Y.-F., Liu, Y., Fu, W.-M., Xu, J., Wang, B., Sun, Y.-X., Wu, T.-Y., Xu, L.-L, Chan, K.-M., Zhang, J.-F., Li, G. Long noncoding RNA H19 accelerates tenogenic differentiation and promotes tendon healing through targeting miR-29b-3p and activating TGF-β1 signaling.

Enhancer of Zeste Homolog 2 Inhibition Stimulates Bone Formation and Mitigates Bone Loss Caused by Ovariectomy in Skeletally Mature Mice

Perturbations in skeletal development and bone degeneration may result in reduced bone mass and quality, leading to greater fracture risk. Bone loss is mitigated by bone protective therapies, but there is a clinical need for new bone-anabolic agents. Previous work has demonstrated that Ezh2 (enhancer of zeste homolog 2), a histone 3 lysine 27 (H3K27) methyltransferase, suppressed differentiation of osteogenic progenitors. Here, we investigated whether inhibition of Ezh2 can be leveraged for bone stimulatory applications. Pharmacologic inhibition and siRNA knockdown of Ezh2 enhanced osteogenic commitment of MC3T3 preosteoblasts. Next generation RNA sequencing of mRNAs and real time quantitative PCR profiling established that Ezh2 inactivation promotes expression of bone-related gene regulators and extracellular matrix proteins. Mechanistically, enhanced gene expression was linked to decreased H3K27 trimethylation (H3K27me3) near transcriptional start sites in genome-wide sequencing of chromatin immunoprecipitations assays. Administration of an Ezh2 inhibitor modestly increases bone density parameters of adult mice. Furthermore, Ezh2 inhibition also alleviated bone loss in an estrogen-deficient mammalian model for osteoporosis. Ezh2 inhibition enhanced expression of Wnt10b and Pth1r and increased the BMP-dependent phosphorylation of Smad1/5. Thus, these data suggest that inhibition of Ezh2 promotes paracrine signaling in osteoblasts and has bone-anabolic and osteoprotective potential in adults.

The degradation of EZH2 mediated by lncRNA ANCR attenuated the invasion and metastasis of breast cancer

EZH2 (the Enhancer of Zeste Homolog 2), as a key epigenetic regulator and EMT inducer, participates in a variety of cancer metastasis. EZH2 stability is regulated by several types of post-translational modifications (PTMs).The long non-coding RNAs (lncRNA) have been implicated to have critical roles in multiple carcinogenesis through a wide range of mechanisms, including modulating the stability of proteins. To date, whether the stability of EZH2 protein is regulated by lncRNAs remains unexplored. Here we report the discovery of ANCR modulating the stability of EZH2, and hence in the invasion and metastasis of breast cancer cells. We determined that ANCR potentiated the CDK1-EZH2 interaction, which then increased the intensity of phosphorylation at Thr-345 and Thr-487 sites of EZH2, facilitating EZH2 ubiquitination and hence its degradation. Moreover, we also uncover ANCR is an important player in breast cancer progression and metastasis mainly through decreasing EZH2 stability. More specifically, we initially found that ANCR level was lower in breast cancer tissues and breast cancer cell lines, in contrast to their normal counterparts. We then demonstrated that knockdown of ANCR induced an EMT program and promoted cell migration and invasion in MCF10A (epithelial cells), whereas ectopic expression of ANCR repressed breast cancer cells migration and invasion. Furthermore, we validated in a nude mouse model that overexpression of ANCR in highly malignant and invasive MDA-MB-231 breast cancer cells significantly reduced the ability of the cells to form tumors and prevented the lung metastasis in vivo. Based on these data, our findings define a new mechanism underlying modulation of EZH2 stability by linking ANCR interaction with EZH2 to promote its phosphorylation that facilitates EZH2 degradation and suppresses breast cancer progression.

High glucose prevents osteogenic differentiation of mesenchymal stem cells via lncRNA AK028326/CXCL13 pathway

BACKGROUND

High glucose (HG) often induces unfavorable effects on proliferation and differentiation of mesenchymal stem cells (MSCs). This study aimed to explore potential molecular pathways underlying HG functional mechanism during osteogenic differentiation of MSCs, involving lncRNA AK028326 and CXCL13.

METHODS

Murine bone marrow-derived MSCs were cultured in osteogenic-inducing medium supplemented with high glucose level at 25mM or 5.5mM as normal control. Expression levels of lncRNA AK028326 and CXCL13 were measured by using real-time PCR. The mineralized nodule formation and alkaline phosphatase (ALP) activity were detected after 21 and 7days of incubation respectively. Western blot were also performed to determine the expression of CXCL13 and osteogenic gene markers. Plasmid pcDNAs and small interference RNAs were transfected as indicated for functional analysis of AK028326 and CXCL13.

RESULTS

HG suppressed the expression of AK028326 and CXCL13 in MSCs in a time-dependent manner, and also the mineralization, ALP activity, and osteogenic gene expression, which could be reversed by overexpression of AK028326 or CXCL13. CXCL13 expression was positively regulated by AK028326 at both mRNA and protein levels. Moreover, CXCL13 mediated the positive regulation of AK028326 on osteogenic gene expression in MSCs and MC3T3-E1 cells, mineralization and ALP activity in MSCs and also HG-induced inhibitory effects during MSCs differentiation into osteoblast.

CONCLUSION

HG could inhibit osteogenic differentiation of MSCs via inhibited expression of CXCL13 mediated by lncRNA AK028326, thereby providing new insights into the molecular mechanism of many osteogenesis-related diseases especially for patients with hyperglycemia.

Epigenetic Regulation of Bone Remodeling and Its Impacts in Osteoporosis

Epigenetics describes mechanisms which control gene expression and cellular processes without changing the DNA sequence. The main mechanisms in epigenetics are DNA methylation in CpG-rich promoters, histone modifications and non-coding RNAs (ncRNAs). DNA methylation modifies the function of the DNA and correlates with gene silencing. Histone modifications including acetylation/deacetylation and phosphorylation act in diverse biological processes such as transcriptional activation/inactivation and DNA repair. Non-coding RNAs play a large part in epigenetic regulation of gene expression in addition to their roles at the transcriptional and post-transcriptional level. Osteoporosis is the most common skeletal disorder, characterized by compromised bone strength and bone micro-architectural deterioration that predisposes the bones to an increased risk of fracture. It is most often caused by an increase in bone resorption that is not sufficiently compensated by a corresponding increase in bone formation. Nowadays it is well accepted that osteoporosis is a multifactorial disorder and there are genetic risk factors for osteoporosis and bone fractures. Here we review emerging evidence that epigenetics contributes to the machinery that can alter DNA structure, gene expression, and cellular differentiation during physiological and pathological bone remodeling.

The Regulatory Effects of Long Noncoding RNA-ANCR on Dental Tissue-Derived Stem Cells

Long noncoding RNAs (lncRNA) have been recognized as important regulators in diverse biological processes, such as transcriptional regulation, stem cell proliferation, and differentiation. Previous study has demonstrated that lncRNA-ANCR (antidifferentiation ncRNA) plays a key role in regulating the proliferation and osteogenic differentiation of periodontal ligament stem cells (PDLSCs). However, little is known about the role of ANCR in regulating other types of dental tissue-derived stem cells (DTSCs) behaviours (including proliferation and multiple-potential of differentiation). In this study, we investigated the regulatory effects of lncRNA-ANCR on the proliferation and differentiation (including osteogenic, adipogenic, and neurogenic differentiation) of DTSCs, including dental pulp stem cells (DPSCs), PDLSCs, and stem cells from the apical papilla (SCAP) by downregulation of lncRNA-ANCR. We found that downregulation of ANCR exerted little effect on proliferation of DPSCs and SCAP but promoted the osteogenic, adipogenic, and neurogenic differentiation of DTSCs. These data provide an insight into the regulatory effects of long noncoding RNA-ANCR on DTSCs and indicate that ANCR is a very important regulatory factor in stem cell differentiation.