MicroRNA-10b promotes nucleus pulposus cell proliferation through RhoC-Akt pathway by targeting HOXD10 in intervetebral disc degeneration

miR-384 suppressed renal cell carcinoma cell proliferation and migration through targeting RAB23

microRNAs (miRNAs) are noncoding, short, and endogenous RNAs that play crucial roles in tumor progression at the post-transcriptional level. Here, we studied the role of miR-384 in the pathogenesis of renal cell carcinoma (RCC). We demonstrated that miR-384 expression was downregulated in the RCC specimens compared with nontumor specimens. Moreover, we showed that RAB23 expression was upregulated in the RCC tissues compared with nontumor tissues. Furthermore, we demonstrated that low expression of miR-384 was correlated with high levels of RAB23 in RCC tissues. We also demonstrated that the RAB23 was a direct target gene of miR-384 in RCC cells. In addition, overexpression of miR-384 suppressed RCC cell proliferation, cell cycle, and cell migration. Furthermore, ectopic expression of RAB23 promoted RCC cell proliferation, cell cycle, and cell migration. These data suggested that miR-384 played a tumor suppressor microRNA in the development of RCC partly through inhibiting RAB23 expression.

Upregulation of miR-107 expression following hyperbaric oxygen treatment suppresses HMGB1/RAGE signaling in degenerated human nucleus pulposus cells

Background

The expression of both high-mobility group box 1 (HMGB1) and receptor for advanced glycation end-products (RAGE) is upregulated in degenerated discs. HMGB1 is known to function as a coupling factor between hypoxia and inflammation in arthritis, and this inflammatory response is modulated by microRNAs (miRNAs), with miR-107 expression downregulated during hypoxia. In this study, we investigated the regulation of the miR-107/HMGB1/RAGE pathway in degenerated nucleus pulposus cells (NPCs) after hyperbaric oxygen (HBO) treatment.

Methods

NPCs were separated from human degenerated intervertebral disc tissues. The control cells were maintained in 5% CO₂/95% air, and the hyperoxic cells were exposed to 100% O₂ at 2.5 atmospheres absolute. MiRNA expression profiling was performed via microarray and confirmed by real-time PCR, and miRNA target genes were identified using bioinformatics and luciferase reporter assays. The cellular protein and mRNA levels of HMGB1, RAGE, and inducible nitric oxide synthase (iNOS) were assessed, and the phosphorylation of MAPK (p38MAPK, ERK, and JNK) was evaluated. Additionally, cytosolic and nuclear fractions of the IκBα and NF-κB p65 proteins were analyzed, and secreted HMGB1 and metalloprotease (MMP) levels in the conditioned media were quantified.

Results

Using microarray analyses, 96 miRNAs were identified as upregulated and 66 downregulated following HBO treatment. Based on these results, miR-107 was selected for further investigation. Bioinformatics analyses indicated that the 3′ untranslated region of the HMGB1 mRNA contained the “seed-matched-sequence” for hsa-miR-107, which was validated via dual-luciferase reporter assays. MiR-107 was markedly induced by HBO, and simultaneous suppression of HMGB1 was observed in NPCs. Knockdown of miR-107 resulted in upregulation of HMGB1 expression in HBO-treated cells, and HBO treatment downregulated the mRNA and protein levels of HMGB1, RAGE, and iNOS and the secretion of HMGB1. In addition, HBO treatment upregulated the protein levels of cytosolic IκBα and decreased the nuclear translocation of NF-κB in NPCs. Moreover, HBO treatment downregulated the phosphorylation of p38MAPK, ERK, and JNK and significantly decreased the secretion of MMP-3, MMP-9, and MMP-13.

Conclusions

HBO inhibits pathways related to HMGB1/RAGE signaling via upregulation of miR-107 expression in degenerated human NPCs.

Long non-coding RNAs in nucleus pulposus cell function and intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is the major cause of low back pain which incurs a significant public-health and economic burden. The aetiology of IDD is complex, with developmental, genetic, biomechanical and biochemical factors contributing to the disease development. Deregulated phenotypes of nucleus pulposus cells, including aberrant differentiation, apoptosis, proliferation and extracellular matrix deposition, are involved in the initiation and progression of IDD. Non-coding RNAs, including long non-coding RNAs (lncRNAs), have recently been identified as important regulators of gene expression. Research into their roles in IDD has been very active over the past 5 years. Our review summarizes current research regarding the roles of deregulated lncRNAs (eg, RP11-296A18.3, TUG1, HCG18) in modulating nucleus pulposus cell functions in IDD. These exciting findings suggest that specific modulation of lncRNAs or their downstream signalling pathways might be an attractive approach for developing novel therapeutics for IDD.

MicroRNA-3619-5p suppresses bladder carcinoma progression by directly targeting β-catenin and CDK2 and activating p21

Current studies indicate that microRNAs (miRNAs) are widely decreased in various tumors and function as tumor suppressors by inhibiting cancer cell proliferation, survival, invasion, and migration. The potential application of using miRNAs to predict therapeutic responses to multiple types of cancer treatment holds high promise. In current study, we demonstrate that miR-3619-5p is downregulated in bladder cancer (BCa) tissues and cells. Exogenous overexpression of miR-3619-5p in BCa cells inhibits proliferation, migration, and invasion. Moreover, a nude mouse xenograft model shows that miR-3619-5p inhibits BCa cell growth. We also demonstrate that miR-3619-5p leads to the activation of p21 by targeting its promoter in BCa cells. Enforced miR-3619-5p expression consistently leads to the downregulation of β-catenin and cyclin-dependent kinase 2 (CDK2) through predicted binding sites within the β-catenin and CDK2 3′-untranslated regions (UTRs), respectively. Moreover, β-catenin and CDK2 knockdown is able to mimic BCa cells growth and metastasis effects induced by overexpressing miR-3619-5p. We further confirm that miR-3619-5p inhibits Wnt-β-catenin signal pathway and EMT progression in BCa cells. We also found that miR-3619-5p-induced growth arrest and metastasis inhibition are p21-dependent in BCa cells. Taken together, these results confirm that miR-3619-5p plays a tumor suppressive role in BCa by interfering with cell growth and metastasis and may serve as a potential therapeutic target in BCa treatment.

Relationship between serum levels of miR-204 and clinical features of patients with lumbar disc herniation - an analysis based on 1,589 cases

This study aims to investigate the relationship between serum miR-204 and clinical features of patients with lumbar disc herniation (LDH). Clinical data of 1589 LDH patients were retrospectively analyzed. There were 953 patients (group A) with a duration of disease shorter than 3 months, and another 636 patients (group B) with a duration of disease longer than 3 months. A total of 300 healthy volunteers were also selected in the same period. Results showed that there was no significant difference in miR-204 expression between males and females (p>0.05). No significant differences in miR-204 expression level were found among different ages (p>0.05). miR-204 in patients with LHD at or below the fourth lumbar vertebrae was significantly higher than those in patients with LHD above the fourth lumbar vertebrae (p<0.05). miR-204 in 1485 patients with abnormal lumbar spine activity was higher than those in healthy controls (p<0.05). miR-204 expression levels was higher in patients with low back pain than those in patients without low back pain. Among patients with low back pain, miR-204 level in patients with spasm-like waist pain was significantly higher than that in patients with persistent dull low back pain (p<0.05). miR-204 increased with the increase in degree of limited walking (p<0.05). There was no significant difference in miR-204 expression level between patients with bilateral lower limb symptoms and patients with unilateral lower limb symptoms (p>0.05), while miR-204 was significantly higher in patients with lower limb symptoms than that in patients without the symptoms (p<0.05). miR-204 was correlated with knee tendon reflex, heel tendon reflex and degree of straight leg raise abnormality. miR-204 was significantly decreased in patients with improvement after treatment. miR-204 level was closely related to the clinical characteristics of LDH. miR-204 may potentially serve as a prognostic marker for patients with LDH.

LncRNA-RMRP promotes nucleus pulposus cell proliferation through regulating miR-206 expression

Long noncoding RNAs (LncRNAs) are involved in the pathogenesis of intervertebral disc degeneration (IDD). However, the biological function and expression of RMRP were still unclear. In our study, we showed that RMRP expression was up‐regulated in degenerated NP tissues compared to normal NP samples, and higher RMRP expression was associated with the disc degeneration grade. Further studies indicated that ectopic expression of RMRP enhanced NP cell growth and also enhanced the expression of ki‐67, PCNA and cyclin D1 in the NP cell. Moreover, overexpression of RMRP promoted the expression of Type II collagen and aggrecan and suppressed the expression of MMP13 and ADAMTS4. In addition, we found that the expression of miR‐206 was down‐regulated in degenerated NP tissues compared to normal NP samples, and lower miR‐206 expression was correlated with the disc degeneration grade. Interestingly, we indicated that miR‐206 expression in NP tissues was negatively correlated with the expression of RMRP. Ectopic expression of miR‐206 suppressed NP cell proliferation and suppressed the expression of Type II collagen and aggrecan and enhanced the expression of MMP13 and ADAMTS4. Furthermore, we demonstrated that overexpression of RMRP increased NP cell growth and regulated ECM expression through targeting miR‐206. These results suggested that lncRNA‐RMRP promoted the progression of IDD through targeting miR‐206, providing an attractive new therapeutic approach for the treatment of IDD disease.

Serum miR-542-3p as a prognostic biomarker in osteosarcoma

OBJECTIVE

Emerging evidence has suggested that circulating microRNAs (miRNAs) in body fluids have novel diagnostic and prognostic significance for patients with malignant diseases. The lack of useful biomarkers is a crucial problem of osteosarcoma (OS); Previous study has reported that miR-542-3p was significantly upregulated in osteosarcoma tissues and miR-542-3p may be as an oncogene in osteosarcoma pathogenesis. In our study, we investigated the circulating miR-542-3p and its clinical relevance in osteosarcoma.

METHODS

Serum MiR-542-3p levels were determined by quantitative real-time PCR assays (qRT-PCR) in 76 patients with OS and 76 healthy volunteers. Patient survival analyses were performed by Kaplan-Meier analyses and Cox regression models. All statistical tests were two-sided.

RESULTS

It was observed that the serum levels of miR-542-3p was significantly higher in patients with OS compared with the control groups (P< 0.01). High serum of miR-542-3p was significantly associated with advanced tumor stage and shorter survival (P< 0.01). ROC curve analysis calculated the ideal miR-542-3p cut-off value of 0.84 in prediction of OS, with a sensitivity of 53.8%, specificity of 93.6%, positive predictive value of 87.3% and negative predictive value of 63.7%.

CONCLUSIONS

The results showed that serum miR-542-3p levels could serve as a non-invasive blood biomarker for tumor monitoring and prognostic prediction in osteosarcoma patients.

miR-148a inhibits pro-inflammatory cytokines released by intervertebral disc cells by regulating the p38/MAPK pathway

The present study aimed to verify the expression and investigate the role of microRNA (miR)-148a in intervertebral disc degeneration (IDD) and explore the associated underlying mechanisms. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to investigate levels of miR-148a in the peripheral blood mononuclear cells (PBMCs) of patients with IDD. To investigate the role of miR-148a in IDD, a stable miR-148a-overexpression/underexpression human nucleus pulposus (NP) cell line was generated by transfection with miR-148a mimic/inhibitor. Then, NP cells were treated with LPS (10 µM) to induce inflammation. The mRNA expression level of miR-148a in NP cells was determined by RT-qPCR and the expression levels of p38 and p-p38 were measured using western blotting. The mRNA expression and supernatant level of pro-inflammatory cytokines, tumor necrosis factor (TNF-α), interleukin (IL)-1β and IL-6, was evaluated by RT-qPCR and ELISA, respectively. The results indicated that miR-148a was significantly downregulated in the PBMCs of IDD patients compared with healthy controls. In vitro upregulation of miR-148a in LPS-stimulated NP cells, by transfection with miR-148a mimic, resulted in inhibition of p-p38 expression; however, inhibition of miR-148a led to overexpression of p-p38. Meanwhile, the production of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) was significantly reduced in miR-148a-overexpressing LPS-stimulated NP cells and significantly increased in miR-148a-underexpressing NP cells. In conclusion, miR-148a inhibits pro-inflammatory cytokines released by intervertebral disc cells via regulation of the p38/mitogen-activated protein kinase pathway.

The long noncoding RNA SNHG1 promotes nucleus pulposus cell proliferation through regulating miR-326 and CCND1

Aberrant nucleus pulposus cell proliferation is implicated in the development of intervertebral disk degeneration (IDD). Recent studies have suggested that long noncoding RNAs (lncRNAs) can modulate cell proliferation in several pathological conditions. Here, we indicate that expression of SNHG1 was upregulated in IDD tissues compared with control tissues and that higher SNHG1 expression was associated with disk degeneration grade. In addition, we show that ectopic expression of SNHG1 promoted nucleus pulposus (NP) cell proliferation and increased the PCNA and cyclin D1 expression in NP cells. Ectopic expression of SNHG1 inhibited miR-326 expression in nucleus pulposus cells and promoted CCND1 expression, which is a direct target gene of SNHG1. Moreover, we demonstrate that expression of miR-326 was downregulated in IDD tissues compared with control tissues and that lower SNHG1 expression was associated with disk degeneration grade. Expression of miR-326 was negatively associated with SNHG1 expression in disk degeneration tissues. Overexpression of miR-326 inhibited NP cell growth and inhibited PCNA and cyclin D1 expression in NP cells. Furthermore, we show that overexpression of SNHG1 promoted nucleus pulposus cell proliferation through inhibiting miR-326 expression. These data shed novel light on the role of SNHG1 in the pathogenesis of IDD.

microRNA-665 promotes the proliferation and matrix degradation of nucleus pulposus through targeting GDF5 in intervertebral disc degeneration

Growing evidences suggested that microRNAs (miRNAs) played important roles in the development of intervertebral disc degeneration (IDD). However, the expression level and function of miR-665 in IDD remain unknown. In this study, we showed that the expression level of miR-665 was upregulated in degenerative human NP samples. In addition, miR-665 expression level gradually increased with the exacerbation of disc degeneration grade. Moreover, miR-665 expression level was positively associated with the Pfirrmann grade. Ectopic expression of miR-665 promoted NP cell growth. Furthermore, miR-665 overexpression decreased aggrecan and Col II expression and ectopic expression of miR-665 increased MMP-3 and MMP-13 expression in NP cell. We identified growth differentiation factor 5 (GDF5) was a direct target gene of miR-665 in NP cell and enforced expression of miR-665 decreased GDF5 expression. Elevated expression of miR-665 enhanced NP cell proliferation and decreased aggrecan and Col II expression. In addition, ectopic expression of miR-665 increased MMP-3 and MMP-13 expression through inhibiting GDF5 expression in NP cells. These results suggested that dysregulated miR-665 expression might act an important role in the development of IDD.

MicroRNA-564 is downregulated in glioblastoma and inhibited proliferation and invasion of glioblastoma cells by targeting TGF-β1

Increasing evidence has indicated that aberrant expression of miRNAs has been shown to be strongly implicated in the initiation and progression of glioblastoma. Here, we identified a novel tumor suppressive miRNA, miR-564, and investigated its role and therapeutic effect for glioblastoma. We showed that miR-564 was down-regulated in human glioblastoma tissues and cell lines. Introduction of miR-564 dramatically inhibited cell growth and invasion in glioblastoma cells. Subsequent experiments revealed that Transforming growth factor-β1 (TGF-β1) was a direct and functional target of miR-564 in glioblastoma cells. Furthermore, overexpression of miR-564 decreased p-SMAD and SMAD4 expression, which are the downstream signaling molecules of TGF-β. Meanwhile, ectopic of miR-564 reduced the messenger RNA (mRNA) and protein expression of epidermal growth factor receptor (EGFR) and MMP9. Furthermore, the upregulation of miR-564 suppressed TGF-β-mediated U87 proliferation and migration. The expression of EGFR and MMP9 was upregulated in glioblastoma tissues compared to their normal tissues. The EGFR and MMP9 expression levels were inverse correlated with the expression of miR-564. miR-564 suppressed the growth of U87-engrafted tumors. These findings reveal that miR-564/TGF-β1 signaling that may be required for glioblastoma development and may consequently serve as a new therapeutic target for the treatment of glioblastoma.

MicroRNA-300 inhibited glioblastoma progression through ROCK1

Glioblastoma is a common type of brain aggressive tumors and has a poor prognosis. MicroRNAs (miRNAs) are a class of small, endogenous and non-coding RNAs that play crucial roles in cell proliferation, survival and invasion. Deregulated expression of miR-300 has been studied in a lot of cancers. However, the role of miR-300 in glioblastoma is still unknown. In this study, we demonstrated that miR-300 expression was downregulated in glioblastoma tissues compared with the normal tissues. Lower expression level of miR-300 was observed in thirty cases (75 %, 30/40) of glioblastoma samples compared with the normal samples. Moreover, the overall survival of glioblastoma patients with lower miR-300 expression level was shorter than those with higher miR-300 expression level. In addition, miR-300 expression was also downregulated in glioblastoma cell lines. Overexpression of miR-300 inhibited cell proliferation, cell cycle and invasion in glioblastoma cell line U87 and U251. Moreover, we identified ROCK1 as a direct target of miR-300 in U87 and U251 cells. Overexpression of ROCK1 partially rescued the miR-300-mediated cell growth. ROCK1 expression levels in glioblastoma tissues were higher than that in normal tissues. ROCK1 expression levels were higher in thirty-one cases of glioblastoma samples than their normal samples. Furthermore, the expression level ROCK1 was inversely correlated with the expression level of miR-300. Importantly, overexpression of miR-300 suppressed glioblastoma progression in an established xenograft model. In conclusion, we revealed that miR-300 might act as a tumor suppressor gene through inhibiting ROCK1 in glioblastoma.

Role of miR-589-3p in human lumbar disc degeneration and its potential mechanism

The present study aimed to investigate the role of miR-589-3p in lumbar disc degeneration (LDD) and to explore the underlying mechanisms. Nucleus pulposus (NP) cells were stimulated with lipopolysaccharide (LPS) to simulate an in vitro model of intervertebral disc degeneration. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression level of microRNA (miR)-589-3p in the NP cells, and the results demonstrated that the increased expression of miR-589-3p in LPS stimulated NP cells compared with the control. To further investigate the role of miR-589-3p in LDD, a human NP cell line with high/low miR-589-3p expression was generated using miR-589-3p mimics/inhibitors. In addition, a human NP cell inflammation model was conducted by LPS (10 µM) treatment. Western blot analysis and RT-qPCR were performed for detection of associated genes and proteins. Protein levels of pro-inflammatory factors, including tumor necrosis factor-α (TNF-α), interleukin (IL)-1β and IL-6 were evaluated by ELISA. Flow cytometry was used for cell apoptosis determination. Furthermore, Targetscan was used to predict potential targets of miR-589-3p, and a dual luciferase reporter assay was used to verify the prediction. The findings verified that miR-589-3p was significantly upregulated in LDD. In vitro, miR-589-3p mimics/inhibitors significantly increased/reduced the production of TNF-α, IL-1β and IL-6 in LPS stimulated NP cells. Furthermore, miR-589-3p mimics/inhibitors significantly promoted/inhibited LPS stimulated NP cell apoptosis. MiR-589-3p mimics/inhibitors significantly repressed/enhanced type II collagen and aggrecan expression in LPS stimulated NP cells. In addition, it was demonstrated that mothers against decapentaplegic homolog (Smad) 4 was a direct target gene of miR-589-3p, and was negatively regulated by miR-589-3p in NP cells. In conclusion, miR-589-3p may function as a promoter in LDD development via the regulation of Smad4.

Emerging roles of MicroRNAs in osteonecrosis of the femoral head

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

Melatonin inhibits nucleus pulposus (NP) cell proliferation and extracellular matrix (ECM) remodeling via the melatonin membrane receptors mediated PI3K-Akt pathway

Pinealectomy in vertebrates accelerated intervertebral disk degeneration (IDD). However, the potential mechanisms, particularly melatonin's role, are still to be clarified. In this study, for first time, melatonin membrane receptors of MT1 and MT2 were found to be present in the human intervertebral disk tissues and nucleus pulposus (NP) cells, respectively. Melatonin treatment significantly inhibited NP cell proliferation in dose-dependent manner. Accordingly, melatonin down-regulated gene expression of cyclin D1, PCNA, matrix metallopeptidase-3, and matrix metallopeptidase-9 and upregulated gene expression of collagen type II alpha 1 chain and aggrecan in NP cells. These effects of melatonin were blocked by luzindole, a nonspecific melatonin membrane receptor antagonist. Signaling pathway analysis indicated that in the intervertebral disk tissues and NP cells, melatonin acted on MT1/2 and subsequently reduced phosphorylation of phosphoinositide 3-kinase p85 regulatory subunit, phosphoinositide-dependent kinase-1, and Akt. The results indicate that melatonin is a crucial regulator of NP cell function and plays a vital role in prevention of IDD.

MiR-448 promotes vascular smooth muscle cell proliferation and migration in through directly targeting MEF2C

Abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) is a critical process in various cardiovascular diseases such as coronary artery disease (CAD), atherosclerosis, stroke, and hypertension. MicroRNAs (miRNAs) are small, short, and noncoding RNAs that inhibit gene expression through binding to the 3'-UTR (3' untranslated regions) of target gene mRNAs. We showed that the expression of miR-448 was upregulated in VSMCs from coronary atherosclerotic plaques compared with normal coronary artery tissues. We also found that PDGF-bb promoted VSMCs proliferation and could induce miR-448 expression. Ectopic miR-448 expression induced VSMCs proliferation. Overexpression of miR-448 induced ki-67 mRNA and protein expression. Moreover, we identified MEF2C was a direct target of miR-448 in VSMCs. Overexpression of miR-448 promoted VSMCs migration. Furthermore, overexpression of MEF2C decreased miR-448-induced VSMCs proliferation and migration. These evidences suggested that miR-448 played an important role in the proliferation and migration of VSMCs.

MicroRNAs: new players in cataract

Cataract is the most common cause of blindness worldwide. Multiple factors such as aging, eye injury, diabetes mellitus, ultraviolet exposure, drug use and other ocular diseases are etiologically linked to cataractogenesis. Due to a rapid increase in aging population, age-related cataract has become the leading cause of blindness. Therefore, it is urgent to understand the molecular mechanism underlying cataractogenesis. MicroRNAs (miRNAs) are a group of endogenous, small noncoding RNAs that regulate gene expression at the post-translational level through binding with the 3'-untranslated regions of target mRNAs. Studies have shown that miRNAs play important roles in multiple cellular functions, including apoptosis, cell proliferation, senescence and stress response. Deregulated expression of miRNAs is also linked to the pathogenesis of many diseases, including ocular diseases. In our review, we focus on miRNAs that are involved in cataract development and discuss their potential applications as novel diagnostic markers and therapeutic targets.

Modulation of chemoresponsiveness to platinum-based agents by microRNAs in cancer

Ovarian cancer accounts for the highest mortality among all gynecologic cancers. Cytoreductive surgery followed by chemotherapy with a platinum-based agent (cisplatin or carboplatin) plus paclitaxel is the first-line option for treatment of epithelial ovarian cancer. However, primary or acquired resistance to platinum-based agents is a major clinical challenge. MicroRNAs are a group of small non-coding RNAs that regulate gene expression post-transcriptionally and may function as oncogenes or tumor-suppressor genes through extensive crosstalk with intracellular signaling pathways. Importantly, their dysregulation has been implicated in ovarian tumorigenesis. Pertinent to chemotherapy, increasing evidence has revealed that miRNAs can be directly linked to chemosensitivity to platinum-based agents in ovarian cancer. In this review, we summarize current evidence concerning the role of miRNAs in prediction and modulation of cellular responses to cisplatin and carboplatin in ovarian cancer.

Inhibition of miR-27a suppresses the inflammatory response via the p38/MAPK pathway in intervertebral disc cells

The current study aimed to investigate the role of miR-27a in intervertebral disc degeneration (IDD) and to examine the underlying mechanisms. Quantitative polymerase chain reaction (qPCR) was performed to detect the expression level of miR-27a in the nucleus pulposus (NP) tissues of patients with IDD, and the results revealed an increasing expression of miR-27a in IDD compared with the control. To further investigate the role of miR-27a in IDD, a stable human NP cell line with low miR-27a expression was generated by transfecting cells with a lentiviral antigomiR-27a inhibitor. In addition, a human NP cell inflammation model was established by lipopolysaccharide (LPS; 10 µM) stimulation. The miR-27a expression in NP cells was determined by qPCR, while the expression of its target proteins; p-p38 and nuclear factor (NF-κB) was measured by western blot analysis. Furthermore, the mRNA and protein expression levels of proinflammatory factors, including interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α), were also evaluated by qPCR and ELISA, respectively. The current results confirmed that miR-27a was significantly upregulated in IDD. In vitro, downregulation of miR-27a in LPS-stimulated NP cells by transfection with the miR-27a inhibitor resulted in suppression of p-p38 and NF-κB expression levels. Furthermore, the production of the proinflammatory factors IL-1β, IL-6 and TNF-α was significantly reduced in LPS-stimulated NP cells with downregulated miR-27a. In conclusion, miR-27a may function as a promoter in IDD development, while inhibition of miR-27a may suppress proinflammatory factors released by intervertebral disc cells by regulating the p38/mitogen-activated protein kinase (MAPK) signaling pathway.

The PI3K/Akt pathway: a critical player in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is thought to be the primary cause of low back pain, a severe public health problem worldwide. Current therapy for IDD aims to alleviate the symptoms and does not target the underlying pathological alternations within the disc. Activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway protects against IDD, which is attributed to increase of ECM content, prevention of cell apoptosis, facilitation of cell proliferation, induction or prevention of cell autophagy, alleviation of oxidative damage, and adaptation of hypoxic microenvironment. In the current review, we summarize recent progression on activation and negative regulation of the PI3K/Akt signaling pathway, and highlight its impact on IDD. Targeting this pathway could become an attractive therapeutic strategy for IDD in the near future.

LncRNA-RP11-296A18.3/miR-138/HIF1A Pathway Regulates the Proliferation ECM Synthesis of Human Nucleus Pulposus Cells (HNPCs)

During the process of Intervertebral disc degeneration (IDD), nucleus pulposus apoptosis increases, extracellular matrix (ECM) alters and/or degrades, abnormal proliferation of cells forms cell clusters, and the expression of various inflammatory factors increases. Thus, regulation of human nucleus pulposus cell (HNPC) proliferation and ECM synthesis present promising strategies for IDD treatment. Accumulating evidence indicates that non-coding RNAs are involved in various cellular processes, including cell proliferation, differentiation, apoptosis, and metastasis. High expression of long non-coding RNA (lncRNA) RP11-296A18.3, as well as a low expression of miR-138 during the IDD process has been reported; yet their functional roles in HNPC proliferation and ECM synthesis still remain unclear. MTT and BrdU assays showed that knockdown of RP11-296A18.3 inhibited the proliferation of HNPC. The ECM marker, MMP-13 and Collagen I expressions were also reduced. Bioinformatics target prediction, qPCR, and luciferase assays identified LncRNA-RP11-296A18.3 interacted with miR-138. Moreover, RP11-296A18.3 regulates HNPC proliferation and ECM synthesis through miR-138. As the target gene of miR-138, hypoxia-inducible factor 1-alpha (HIF1A) was closely associated with cell proliferation which was also regulated by RP11-296A18.3 via miR-138. Immunochemistry and qPCR results showed that miR-138 expression was inversely correlated to RP11-296A18.3 and HIF1A in IDD tissues, respectively; RP11-296A18.3 was positively correlated to HIF1A. We revealed that RP11-296A18.3 promote HIF1A expression through sponging miR-138, thus to promote HNPC proliferation and ECM synthesis. Targeting RP11-296A18.3 to rescue miR-138 expression in HNPCs and IDD tissues presents a promising strategy for IDD improvement. J. Cell. Biochem. 118: 4862-4871, 2017. © 2017 Wiley Periodicals, Inc.

Dysregulated miR-127-5p contributes to type II collagen degradation by targeting matrix metalloproteinase-13 in human intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IDD) is a chronic disease associated with the degradation of extracellular matrix (ECM). Matrix metalloproteinase (MMP)-13 is a major enzyme that mediates the degradation of ECM components. MMP-13 has been predicted to be a potential target of miR-127-5p. However, the exact function of miR-127-5p in IDD is still unclear.

OBJECTIVE

We designed this study to evaluate the correlation between miR-127-5p level and the degeneration of human intervertebral discs and explore the potential mechanisms.

METHODS

miR-127-5p levels and MMP-13 mRNA levels were detected by quantitative real-time polymerase chain reaction (qPCR). To determine whether MMP-13 is a target of miR-127-5p, dual luciferase reporter assays were performed. miR-127-5p mimic and miR-127-5p inhibitor were used to overexpress or downregulate miR-127-5p expression in human NP cells, respectively. Small interfering RNA (siRNA) was used to knock down MMP-13 expression in human NP cells. Type II collagen expression in human NP cells was detected by qPCR, western blotting, and immunofluorescence staining.

RESULTS

We confirmed that miR-127-5p was significantly downregulated in nucleus pulposus (NP) tissue of degenerative discs and its expression was inversely correlated with MMP-13 mRNA levels. We reveal that MMP-13 may act as a target of miR-127-5p. Expression of miR-127-5p was inversely correlated with type II collagen expression in human NP cells. Moreover, suppression of MMP-13 expression by siRNA blocked downstream signaling and increased type II collagen expression.

CONCLUSION

Dysregulated miR-127-5p contributed to the degradation of type II collagen by targeting MMP-13 in human IDD. Our findings highlight that miR-127-5p may serve as a new therapeutic target in IDD.

MicroRNA-223 demonstrated experimentally in exosome-like vesicles is associated with decreased risk of persistent pain after lumbar disc herniation

Background

Previous findings have demonstrated that lumbar radicular pain after disc herniation may be associated with up-regulation of inflammatory mediators. In the present study we examined the possible role of extracellular microRNAs (miRs) in this process.

Methods

Single unit recordings, isolation of exosome-like vesicles, electron microscopy, nanoparticle tracking analysis, western blot analysis and qPCR were used in rats to demonstrate the effect of nucleus pulposus (NP) applied onto the dorsal nerve roots. ELISA and qPCR were used to measure the level of circulating IL-6 and miRs in a 1-year observational study in patients after disc herniation.

Results

In the rats, enhanced spinal cord nociceptive responses were displayed after NP applied onto the dorsal nerve roots. An increased release of small non-coding RNAs, including miR-223, miR-760 and miR-145, from NP in exosome-like vesicles was demonstrated. In particular, the NP expression of miR-223, which inhibited the nociceptive spinal signalling, was increased. In the patients, increased extracellular miR-223 was also verified in the acute phase after disc herniation. The increased miR-223 expression was, however, only observed in those who recovered (sex, age and smoking were included as covariates).

Conclusions

Our findings suggest that miR-223, which can be released from the NP after disc herniation, attenuates the neuronal activity in the pain pathways. Dysregulation of miR-223 may predict chronic lumbar radicular pain.

Trial registration/ethics REK 2014/1725

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1194-8) contains supplementary material, which is available to authorized users.

MicroRNA-610 suppresses osteosarcoma oncogenicity via targeting TWIST1 expression

Osteosarcoma is the most frequent primary bone tumor affects adolescents and young adults. Recently, microRNAs (miRNAs) are short, non-coding and endogenous RNAs that played as important roles in the initiation and progression of tumors. In this study, we try to explore the biological function and expression of miR-610 in the osteosarcoma. We showed that miR-610 expression was downregulated in the osteosarcoma tissues and cell lines. Elevated expression of miR-610 suppressed the osteosarcoma cell proliferation, cell cycle, invasion and EMT program. Moreover, overexpression of miR-610 increased sensitivity of MG-63 and U2OS cells to cisplatin. Twist1 was identified as a direct target gene of miR-610 in the osteosarcoma cell. Furthermore, we demonstrated that Twist1 was upregulated in the osteosarcoma tissues and cell lines. The expression of Twist1 was negatively associated with the expression of miR-610 expression in the osteosarcoma tissues. Ectopic expression of Twist1 inhibited the sensitivity of miR-610-overexpressing MG-63 cells to cisplatin. We also showed that overexpression of Twist1 increased the proliferation and invasion of miR-610-overexpressing MG-63 cells. These data indicated that ectopic expression of miR-610 suppressed the osteosarcoma cell proliferation, cell cylce, invasion and increased the sensitivity of osteosarcoma cells to cisplatin through targeting the Twist1 expression.

Overexpression of miR-10b in colorectal cancer patients: Correlation with TWIST-1 and E-cadherin expression

MicroRNAs are emergent players of epigenetics that function as oncogenes or tumor suppressors and that have been implicated in regulating diverse cellular pathways. MiR-10b is an oncogenic microRNA involved in tumor invasion and metastasis in various cancers. Our data have shown that miR-10b is overexpressed in colorectal cancer samples in comparison with non-tumorous adjacent mucosa (p = 0.0025) and that it is associated with severe features such as tumor size >5 cm (p = 0.023), distant metastasis (p = 0.0022), non-differentiated tumors (p = 0.016), and vascular invasion (p = 0.01). Regarding the regulation of its expression, positive correlation between the loss of miR-10b and aberrant DNA methylation (p = 0.02) as well as a loss of TWIST-1 messenger RNA (p = 0.018) have been observed. Furthermore, expression analysis of the downstream miR-10b targets has shown that there are associations between low HOXD10 messenger RNA and E-cadherin protein levels (p < 0.0001, p = 0.0008, respectively) and overexpression of miR-10b. Our data suggests that overexpression of miR-10b results from high levels of TWIST-1 and may induce a decrease of E-cadherin membranous protein levels, thus contributing to the acquisition of metastatic phenotypes in colorectal cancer.

Overexpression of miR-519d in lung adenocarcinoma inhibits cell proliferation and invasion via the association of eIF4H

Lung cancer is one of the deadliest types of cancer worldwide due to its high mortality rate. Adenocarcinoma constitutes 20%-30% of all lung cancers. In recent years, studies on the mechanisms of lung tumorigenesis and development have in part focused on the microRNAs for their crucial role in the progress of different cancers. As for our study, we demonstrated that miR-519d was differently downregulated and eIF4H was significantly overexpressed in lung adenocarcinoma via the detection of quantitative real-time polymerase chain reaction compared with the adjacent normal tissues. Furthermore, Cell Counting Kit-8 assay, colony formation assay, xenograft tumor experiment, Ki67 immunohistochemistry assay and transwell assay were performed to explain that the upregulated miR-519d could inhibit the proliferation and invasion of A549 and H1299 cells. To further advance our understanding of the mechanisms of miR-519d, we performed the bioinformatics analysis and the luciferase report assay. The results from these procedures revealed eIF4H to be one of the targets of miR-519d. Downregulated eIF4H was analogous to the overexpressed miR-519d obtained from miR-519d agomir and si-eIF4H transfection. In summary, it can be concluded that miR-519d targets eIF4H in lung adenocarcinoma to inhibit cell proliferation and invasion. This mechanism may offer new insights into the tumorigenesis and development of lung adenocarcinoma.

MicroRNA-802 plays a tumour suppressive role in tongue squamous cell carcinoma through directly targeting MAP2K4

OBJECTIVES

Tongue squamous cell carcinoma (TSCC) is the most common oral tumours. MicroRNAs play crucial roles in many cell processes including cell viability, development, apoptosis, migration and invasion. The role of miR-802 in the TSCC is still unknown.

MATERIALS AND METHODS

The miR-802 expression in TSCC tissues and cell lines was determined by quantitative real-time polymerase chain reaction. CCK-8 assay was performed to measure the cell viability, while the cell invasion assay was used to determine the cell invasion. Dual-luciferase reporter and western blot were used to confirm the potential target gene of miR-802.

RESULTS

In our study, we demonstrated that miR-802 expression was downregulated in TSCC tissues and cell lines. Elevated expression of miR-802 suppressed the TSCC cell viability and invasion. Moreover, enforced expression of miR-802 increased the expression of E-cadherin, while suppressed the expression of N-cadherin, Snail and Vimentin in the TSCC cell. In addition, we identified the mitogen-activated protein kinase 4 (MAP2K4) as a direct target gene of miR-802 in the TSCC cell. We also demonstrated that the expression of MAP2K4 was higher in the TSCC tissues than that in the adjacent normal tissues. Furthermore, the expression level of MAP2K4 was inversely associated with the expression of miR-802 in TSCC tissues. We also demonstrated that the MAP2K4 expression was upregulated in TSCC cell lines. Elevated expression of miR-802 inhibited TSCC cell viability and invasion through inhibiting MAP2K4 expression.

CONCLUSIONS

Our data revealed that miR-802 played as a tumour suppressor gene and might act as a therapeutic target in TSCC patients.

miR-613 inhibits bladder cancer proliferation and migration through targeting SphK1

OBJECTIVES

Increasing evidence has suggested that microRNA (miRNA) dysregulation may contribute to tumor progression and metastasis. However, the role of miR-613 in bladder cancer was still unknown.

MATERIALS AND METHODS

qRT-PCR and Western blotting were performed to detect the expression of miR-613 and its direct target gene. CCK-8 analysis, qRT-PCR and cell invasion were performed to measure the cell function.

RESULTS

We demonstrated that the expression of miR-613 was downregulated in the bladder cancer cell lines. In addition, miR-613 expression was downregulated in the bladder cancer tissues compared to the adjacent normal tissues. Out of 35 bladder cancer tissues, miR-613 was downregulated in 27 cases compared to the adjacent tissues. Ectopic expression of miR-613 suppressed the bladder cancer cell proliferation and invasion. Moreover, miR-613 overexpression enhanced the expression of epithelial biomarker, Ecadherin, and suppressed the expression of mesenchymal biomarker, Vimentin, Snail and N-cadherin. Furthermore, we identified the Sphingosine kinase 1 (SphK1) as the direct target gene of miR-613 in the bladder cancer cell. Restoration of Sphk1 partially rescued miR-613-inhibited bladder cancer cell proliferation, invasion and EMT.

CONCLUSIONS

These data suggested that miR-613 acted a tumor suppressive role in bladder cancer through targeting SphK1 in bladder.

MicroRNA-379 suppresses osteosarcoma progression by targeting PDK1

Osteosarcoma is the most common primary bone tumour. Increasing evidence has demonstrated the pathogenic role of microRNA (miRNAs) dysregulation in tumour development. miR-379 was previously reported to function as an oncogenic or tumour-suppressing miRNA in a tissue-dependent manner. However, its function in osteosarcoma remains unknown. In this study, we found that the expression of miR-379 was downregulated in osteosarcoma tissues and cell lines. Further functional characterization revealed that miR-379 suppressed osteosarcoma cell proliferation and invasion in vitro and retarded the growth of osteosarcoma xenografts in vivo. Mechanistically, PDK1 was identified as the direct target of miR-379 in osteosarcoma, in which PDK1 expression was up-regulated and showed inverse correlation with miR-379. Enforced expression of PDK1 promoted osteosarcoma cell proliferation and rescued the anti-proliferative effect of miR-379. These data suggest that miR-379 could function as a tumour-suppressing miRNA via targeting PDK1 in osteosarcoma.

Effect of microRNA-21 on the proliferation of human degenerated nucleus pulposus by targeting programmed cell death 4

This study aims to explore the effect of microRNA-21 (miR-21) on the proliferation of human degenerated nucleus pulposus (NP) by targeting programmed cell death 4 (PDCD4) tumor suppressor. NP tissues were collected from 20 intervertebral disc degeneration (IDD) patients, and from 5 patients with traumatic spine fracture. MiR-21 expressions were tested. NP cells from IDD patients were collected and divided into blank control group, negative control group (transfected with miR-21 negative sequences), miR-21 inhibitor group (transfected with miR-21 inhibitors), miR-21 mimics group (transfected with miR-21 mimics) and PDCD4 siRNA group (transfected with PDCD4 siRNAs). Cell growth was estimated by Cell Counting Kit-8; PDCD4, MMP-2,MMP-9 mRNA expressions were evaluated by qRT-PCR; PDCD4, c-Jun and p-c-Jun expressions were tested using western blot. In IDD patients, the expressions of miR-21 and PDCD4 mRNA were respectively elevated and decreased (both P<0.05). The miR-21 expressions were positively correlated with Pfirrmann grades, but negatively correlated with PDCD4 mRNA (both P<0.001). In miR-21 inhibitor group, cell growth, MMP-2 and MMP-9 mRNA expressions, and p-c-Jun protein expressions were significantly lower, while PDCD4 mRNA and protein expressions were higher than the other groups (all P<0.05). These expressions in the PDCD4 siRNA and miR-21 mimics groups was inverted compared to that in the miR-21 inhibitor group (all P<0.05). MiR-21 could promote the proliferation of human degenerated NP cells by targeting PDCD4, increasing phosphorylation of c-Jun protein, and activating AP-1-dependent transcription of MMPs, indicating that miR-21 may be a crucial biomarker in the pathogenesis of IDD.

miR-628-3p regulates osteoblast differentiation by targeting RUNX2: Possible role in atrophic non-union

Atrophic non-union is a serious complication of fractures. The underlying biological mechanisms involved in its pathogenesis are not yet completely understood. MicroRNAs (miRNAs or miRs) are a type of endogenous small non-coding RNA, which participate in various physiological and pathophysiological processes. In this study, differentially expressed miRNAs were screened in patients with atrophic nonunion. In total, 4 miRNAs (miR-149^*, miR-221, miR-628-3p and miR-654-5p) were upregulated and 7 miRNAs (let-7b^*, miR-220b, miR-513a-3p, miR-551a, miR-576-5p, miR-1236 and kshv-miR-K12-6-5p) were downregulated at the fracture sites in patients with atrophic non-union. Among the upregulated miRNAs, miR-628-3p and miR-654-5p expression was found to be persistently decreased during osteoblast differentiation, indicating their possible inhibitory effect on osteogenesis. Gain-of-function experiment demonstrated that miR-628-3p, but not miR-654-5p, attenuated osteoblast differentiation. Further, in silico analysis revealed that runt-related transcription factor 2 (RUNX2), the master transcript factor for osteoblast differentiation, was the target of miR-628-3p, which had two binding site-condense regions in the 3′ untranslated region. The exact binding site of miR-628-3p was further identified with luciferase reporter assay. In addition, the overexpression of miR-628-3p appeared to be associated with the suppression of RUNX2 expression at both the mRNA and protein level, suggesting that miR-628-3p inhibits osteoblast differentiation via RUNX2. On the whole, the findings of this study provide evidence of the upregulation of miR-628-3p in patients with atrophic non-union and that miR-628-3p may exert an inhibitory effect on osteogenesis via the suppression of its target gene, RUNX2. The study provides valuable insight into the pathogenesis of atrophic non-union and suggests new potential therapeutic targets for the treatment of this disorder.

miR-454 functions as an oncogene by inhibiting CHD5 in hepatocellular carcinoma

Previous studies showed that miR-454 acted as an oncogene or tumor suppressor in cancer. However, its function in HCC remains unknown. In this study, we found that miR-454 expression was upregulated in HCC cell lines and tissues. Knockdown of miR-454 inhibited HCC cell proliferation and invasion and epithelial mesenchymal transition (EMT), whereas overexpression of miR-454 promoted HCC cell proliferation and invasion and EMT. Furthermore, we identified the CHD5 as a direct target of miR-454. CHD5 was downregulated in HCC tissues and cell lines and the expression level of CHD5 was inversely correlated with the expression of miR-454 in HCC tissues. In addition, knockdown of miR-454 inhibited the growth of HepG2-engrafted tumors in vivo. Taken together, these results indicated that miR-454 functioned as an oncogene in HCC.

Ablation of miR-10b Suppresses Oncogene-Induced Mammary Tumorigenesis and Metastasis and Reactivates Tumor-Suppressive Pathways

The invasive and metastatic properties of many human tumors have been associated with upregulation of the miRNA miR-10b, but its functional contributions in this setting have not been fully unraveled. Here, we report the generation of miR-10b-deficient mice, in which miR-10b is shown to be largely dispensable for normal development but critical to tumorigenesis. Loss of miR-10b delays oncogene-induced mammary tumorigenesis and suppresses epithelial-mesenchymal transition, intravasation, and metastasis in a mouse model of metastatic breast cancer. Among the target genes of miR-10b, the tumor suppressor genes Tbx5 and Pten and the metastasis suppressor gene Hoxd10 are significantly upregulated by miR-10b deletion. Mechanistically, miR-10b promotes breast cancer cell proliferation, migration, and invasion through inhibition of the expression of the transcription factor TBX5, leading to repression of the tumor suppressor genes DYRK1A and PTEN In clinical specimens of breast cancer, the expression of TBX5, HOXD10, and DYRK1A correlates with relapse-free survival and overall survival outcomes in patients. Our results establish miR-10b as an oncomiR that drives metastasis, termed a metastamiR, and define the set of critical tumor suppressor mechanisms it overcomes to drive breast cancer progression. Cancer Res; 76(21); 6424-35. ©2016 AACR.

Porcine milk-derived exosomes promote proliferation of intestinal epithelial cells

Milk-derived exosomes were identified as a novel mechanism of mother-to-child transmission of regulatory molecules, but their functions in intestinal tissues of neonates are not well-studied. Here, we characterized potential roles of porcine milk-derived exosomes in the intestinal tract. In vitro, treatment with milk-derived exosomes (27 ± 3 ng and 55 ± 5 ng total RNA) significantly promoted IPEC-J2 cell proliferation by MTT, CCK8, EdU fluorescence and EdU flow cytometry assays. The qRT-PCR and Western blot analyses indicated milk-derived exosomes (0.27 ± 0.03 μg total RNA) significantly promoted expression of CDX2, IGF-1R and PCNA, and inhibited p53 gene expression involved in intestinal proliferation. Additionally, six detected miRNAs were significantly increased in IPEC-J2 cell, while FAS and SERPINE were significantly down-regulated relative to that in control. In vivo, treated groups (0.125 μg and 0.25 μg total RNA) significantly raised mice' villus height, crypt depth and ratio of villus length to crypt depth of intestinal tissues, significantly increased CDX2, PCNA and IGF-1R' expression and significantly inhibited p53' expression. Our study demonstrated that milk-derived exosomes can facilitate intestinal cell proliferation and intestinal tract development, thus giving a new insight for milk nutrition and newborn development and health.

MicroRNA-561 inhibits gastric cancercell proliferation and invasion by downregulating c-Myc expression

Gastric cancer (GC) causes nearly one million deaths worldwide each year. However, the molecular pathway of GC development remains unclear. Increasing evidences have shown that microRNAs (miRNAs) are highly associated with tumor development. However, relative little is known about the potential role of miRNAs in gastric cancer development. In the present study, we showed that miR-561 was down-regulated frequently in human GCs cell lines and tissues, and its expression was associated with tumor-node-metastasis (pTNM) stage. Enforced expression of miR-561 in GC cells inhibited cell proliferation and invasion in vitro. In contrast, knockdown of miR-561 had the opposite effect on cell proliferation and invasion. Moreover, c-Myc was identified as a potential miR-561 target. Further studies confirmed that miR-561 suppressed the expression of c-Myc by directly binding to its 3'-untranslated region. Restoration of c-Myc in miR-561-overexpressed GC cells reversed the suppressive effects of miR-561 and c-Myc was inversely correlated with miR-561 expression in GC tissues. These results demonstrate that miR-561 acts as a novel tumor suppressor in GC by targeting c-Myc gene and inhibiting GC cells proliferation and invasion. These findings contribute to current understanding of the functions of miR-561 in GC.

MiR-300 suppresses laryngeal squamous cell carcinoma proliferation and metastasis by targeting ROS1

Laryngeal squamous cell carcinoma (LSCC) is a common aggressive head and neck cancer with high mortality and incidence. MicroRNAs (miRNAs) are short, non-coding and endogenous RNAs that posttranscriptionally inhibit gene expression. In this study, we showed that miR-300 expression was downregulated in LSCC tissues compared with adjacent no-tumor tissues. MiR-300 overexpression inhibited Hep-2 cell proliferation, as well as the expression of ki-67 and PCNA. Moreover, overexpression of miR-300 repressed the cell invasion in Hep-2 cells. We identified c-ros oncogene 1 receptor tyrosine kinase (ROS1) as a direct target gene of miR-300 in Hep-2 cell. Furthermore, ROS1 expression was upregulated in LSCC tissues compared with adjacent no-tumor tissues. Interesting, there were an inverse correlation between ROS1 and miR-300 expression in the LSCC tissues. Overexpression of ROS1 increased the Hep-2 cells proliferation and invasion. Overexpression of ROS1 abrogated miR-300 induced cell growth and invasion inhibition. Therefore, our data suggested that miR-300 acted as a tumor suppressive gene in LSCC.

The role of microRNAs in intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary hepatic malignancy with poor prognosis. Despite improvements in its diagnosis and therapy, the prognosis for ICC patients remains poor. An improved understanding of ICC pathogenesis and consequential identification of novel therapeutic targets would improve the prognosis of ICC patients. MicroRNAs (miRNAs) are a class of highly conserved, endogenous, small non‐coding RNA molecules of 18–23 nucleotides in length, which regulate gene expression through complementary base‐pairing with target messenger RNAs and subsequent gene silencing. Several studies have shown deregulated expression of miRNAs in ICC cell lines and tissues, in which these miRNAs play important roles in ICC apoptosis, cell proliferation, invasion, migration and metastasis. In this review, we illustrate the potential role of miRNA in the pathogenesis of ICC and explore the possibilities of using miRNAs as prognostic and diagnostic markers, as well as therapeutic targets in ICC.

MicroRNA-137 suppresses tongue squamous carcinoma cell proliferation, migration and invasion

OBJECTIVES

Tongue squamous cell carcinoma (TSCC) is the most frequent type of oral malignancy. Increasing evidence has shown that miRNAs play key roles in many biological processes such as cell development, invasion, proliferation, differentiation, metabolism, apoptosis and migration.

MATERIALS AND METHODS

qRT-PCR analysis was performed to measure miR-137 expression. CCK-8 analysis, cell colony formation, wound-healing analysis and invasion were performed to detect resultant cell functions. The direct target of miR-137 was labelled and measured by luciferase assay and Western blotting.

RESULTS

We demonstrated that expression of miR-137 was downregulated in TSCC tissues compared to matched normal ones. miR-137 expression was downregulated in TSCC lines (SCC4, SCC1, UM1 and Cal27) compared to the immortalized NOK16B cell line and normal oral keratinocytes in culture (NHOK). In addition, we have shown that miR-137 expression was epigenetically regulated in TSCCs. Overexpression of miR-137 suppressed TSCC proliferation and colony formation. Ectopic expression of miR-137 promoted expression of the epithelial biomarker, E-cadherin, and inhibited the mesenchymal biomarker, N-cadherin, as well as vimentin and Snail expression, indicating that miR-137 suppressed TSCC epithelial-mesenchymal transition (EMT). We also showed that ectopic expression of miR-137 inhibited TSCC invasion and migration. In addition, we identified SP1 as a direct target gene of miR-137 in SCC1 cells. SP1 overexpression rescued inhibitory effects exerted by miR-137 on cell proliferation and EMT.

CONCLUSIONS

These results indicate that miR-137 acted as a tumour suppressor in TSCC by targeting SP1.

miR-297 acts as an oncogene by targeting GPC5 in lung adenocarcinoma

OBJECTIVES

Emerging studies have demonstrated that microRNAs (miRNAs) play crucial roles in carcinogenesis of many developing human tumours. However, the functions and mechanisms of miR-297 in lung cancer have, up to now, been largely undefined.

MATERIALS AND METHODS

Here, miR-297 expression was measured in lung adenocarcinoma tissues and cell lines, using qRT-PCR. Lung adenocarcinoma cell line was treated with an miR-297 mimic. MTT and colony analysis were performed to detect cell proliferation and colony formation. The direct target gene of miR-297 was assessed by qRT-PCR, Western blotting and luciferase assays.

RESULTS

We demonstrated that miR-297 expression was upregulated in lung adenocarcinomas compared to adjacent normal tissues. Expression of miR-297 was also upregulated in tested lung adenocarcinoma cell lines. Ectopic expression of miR-297 enhanced lung adenocarcinoma cell proliferation and colony formation. Furthermore, overexpression of miR-297 promoted cell migration and invasion. In addition, we identified Glypican-5 (GPC5) as a direct target gene of miR-297 in lung adenocarcinoma cells. Expression of GPC5 was downregulated in both lung adenocarcinoma tissues and cell lines. Moreover, expression of GPC5 was inversely associated with expression of miR-297 in lung adenocarcinoma tissues.

CONCLUSIONS

These results suggest that miR-297 acted as an oncogenic miRNA, partly by targeting GPC5, adenocarcinoma of the lung.

MicroRNA-765 regulates neural stem cell proliferation and differentiation by modulating Hes1 expression

Neural stem cells (NSCs) are multipotent, self-renewing and undifferentiated cells that have the ability to differentiate to both glial and neuronal lineages. miRNAs act a key role in regulating neuronal fate and self-renewal of NSCs. In this study, we found that ectopic expression of miR-765 promoted NSCs proliferation. Moreover, miR-765 overexpression increased the ki-67 and β-tubulin-III expression inNSCs. Overexpression of miR-765 inhibited the expression of GFAP in NSCs. Furthermore, Hes1 was identified as a direct target gene of miR-765 in NSCs. Overexpression of Hes1 decreased miR-765-induced proliferation of NSCs and inhibited NSCs differentiation to neurons in miR-765-treated NSCs. These results demonstrated that miR-765 acted a crucial role in NSCs differentiation and proliferation by inhibiting Hes1 expression.

Inhibition of microRNA-34a prevents IL-1β-induced extracellular matrix degradation in nucleus pulposus by increasing GDF5 expression

Accumulating evidence indicates that miRNAs, a class of small non-coding RNAs, are implicated in the pathogenesis of various diseases such as cancer and intervertebral disc degeneration. The aim of this study was to investigate the expression and the biological function of microRNA-34a in intervertebral disc degeneration. In this study, microRNA-34a expression was assessed in nucleus pulposus specimens and in IL-1β-stimulated nucleus pulposus cells by real-time polymerase chain reaction. microRNA-34a functions were investigated by using gain and loss of function experiments in nucleus pulposus cells and a dual luciferase reporter assay in 293T cells. microRNA-34a was dramatically up-regulated in degenerative nucleus pulposus tissues and in IL-1β-stimulated nucleus pulposus cells when compared with controls. Furthermore, growth differentiation factor 5 was identified as a target of microRNA-34a. Aberrant expression of microRNA-34a inhibited growth differentiation factor 5 expression by direct binding to its 3'-untranslated region. This inhibition was abolished by mutation of the microRNA-34a binding sites. In addition, microRNA-34a silencing reversed IL-1β-induced decrease in type II collagen and aggrecan expression in nucleus pulposus cells. This effect was substantially suppressed by growth differentiation factor 5 silencing. Our results suggested that microRNA-34a inhibition prevents IL-1β-induced extracellular matrix degradation in human nucleus pulposus by increasing growth differentiation factor 5 expression. microRNA-34a inhibition may be a novel molecular target for intervertebral disc degeneration treatment through the prevention of nucleus pulposus extracellular matrix degradation.

Dysregulated miR-133a Mediates Loss of Type II Collagen by Directly Targeting Matrix Metalloproteinase 9 (MMP9) in Human Intervertebral Disc Degeneration

STUDY DESIGN

A microRNA (miRNA) study using Solexa sequencing.

OBJECTIVE

The purpose of this study was to identify intervertebral disc degeneration (IDD)-specific miRNA expression profile, and to validate its biological function.

SUMMARY OF BACKGROUND DATA

Accumulating evidence indicates that miRNAs play a critical role in IDD, but the role of specific miRNAs involved in this entity remains unclear.

METHODS

MiRNA expression profile was determined in nucleus pulposus (NP) tissues from patients with IDD and controls, employing Solexa sequencing and quantitative real-time PCR (qRT-PCR). Biological functions of differential expression miRNAs were further investigated. Luciferase reporter assays and western blotting were performed to determine miRNA targets.

RESULTS

We identified 31 miRNAs that were differentially expressed (22 upregulated and nine downregulated) in patients compared with controls. After qRT-PCR confirmation, miR-133a was significantly down-regulated in degenerative NP tissues. Moreover, its level was inversely correlated with grade of disc degeneration. Through gain- and loss-of-function studies, miR-133a was demonstrated to significantly promote type II collagen expression in NP cells. MMP9 was identified as a target of miR-133a. Knockdown of MMP9 induced effects on NP cells similar to those induced by miR-133a. Expression of MMP9 was inversely correlated with miR-133a expression in degenerative NP tissues.

CONCLUSION

These results suggest that the downregulation of miR-133a induces type II collagen loss by directly targeting MMP9. Our findings also highlight miR-133a as a novel hopeful therapeutic target for IDD.

LEVEL OF EVIDENCE

3.

Role of microRNA-210 in human intervertebral disc degeneration

The present study aimed to investigate the role of microRNA (miR)-210 in the development of intervertebral disc degeneration (IDD). Human nucleus pulposus (NP) samples were collected from patients with scoliosis and IDD (n=12 each) as the scoliosis control and IDD groups, respectively. The expression levels of miR-210 were detected using reverse-transcription quantitative polymerase chain reaction. In vitro overexpression and knockdown of miR-210 in human NP cells were achieved by transfection of NP cells with lentiviral pre-miR-210 and antagomiR-210, respectively. The protein expression levels of homeobox A9 (HOXA9) were then detected in NP cells with modulated miR-210 using western blot analysis. Flow cytometry with allophycocyanin-Annexin V/7 and 7-aminoactinomycin D staining was also used to detect the proportion of NP cells with modulated miR-210 undergoing apoptosis. The current study revealed that the miR-210 expression was decreased in patients with IDD compared with that of the scoliosis control group (P<0.05). Furthermore, the upregulation of miR-210 with pre-miR-210 led to the repression of HOXA9. The HOXA9 level was significantly lower in these cells compared with that of NP cells treated with a corresponding negative sequence (P<0.05). Knockdown of miR-210 with antagomiR-210 resulted in upregulation of HOXA9 in NP cells, determined as the level of HOXA9 was significantly higher than that of NP cells treated with a negative sequence (P<0.05). The proportion of apoptotic NP cells also significantly decreased following treatment with pre-miR-210 compared with the scoliosis control group (12.1±1.43 vs. 23.8±1.22%, respectively; P<0.05). In conclusion, downregulation of miR-210 may promote Fas-mediated apoptosis in human IDD by regulating the expression of HOXA9. This indicates that miR-210 may be closely associated with the development of IDD and may act as a novel target in IDD treatment.

miR-10b promotes invasion by targeting HOXD10 in colorectal cancer

Studies have shown that homeobox D10 (HOXD10) is the target gene of microRNA-10b (miR-10b) and is closely associated with the inhibition of cell migration and invasion. Ras homolog family member C (RhoC) has been reported to promote tumor metastasis in various types of cancer. The effect of miR-10b on colorectal cancer (CRC) metastasis and the associated molecular mechanisms remain elusive. The present study aimed to investigate whether miR-10b could promote invasion by targeting HOXD10 in CRC by exploring the association between miR-10b and HOXD10 expression in CRC patients. The findings revealed that miR-10b levels were elevated in the CRC specimens and significantly correlated with advanced clinical stage and lymph node metastasis. In addition, HOXD10 was a direct target of miR-10b, and the increased expression of RhoC and downregulation of HOXD10 correlated with the increased expression level of miR-10b. HOXD10 protein level was also markedly attenuated in lymph node metastasis-positive tumor tissues compared with lymph node metastasis-free tumor tissues. These findings suggest that miR-10b may stimulate the upregulation of RhoC through targeting HOXD10, thus promoting the invasion and migration in CRC tumor.

MiR-138-5p promotes TNF-α-induced apoptosis in human intervertebral disc degeneration by targeting SIRT1 through PTEN/PI3K/Akt signaling

The role of apoptosis in the pathogenesis of intervertebral disc degeneration (IDD) remains enigmatic. Accumulating evidence has shown that the apoptotic machinery is regulated by miRNAs. The aim of this study was to evaluate the effect of miR-138-5p on apoptosis in human NP cells induced by TNF-α and to explore the mechanism of this process. The expression of miR-138-5p was determined in nucleus pulposus (NP) tissues from patients with IDD and controls using RT-qPCR, and we showed that miR-138-5p was significantly upregulated in degenerative NP tissues. Additionally, TNF-α-induced apoptosis was inhibited when using a miR-138-5p inhibitor in human NP cells, and silencing of miR-138-5p dramatically suppressed the expression of cleaved caspase-3. Moreover, bioinformatics target prediction identified SIRT1 as a putative target of miR-138-5p. Knockdown of miR-138-5p was shown to upregulate SIRT1 expression by direct targeting its 3'-UTR, an effect that was abolished by mutation of the miR-138-5p binding sites. Furthermore, inhibition of miR-138-5p downregulated PTEN protein expression and promoted activation of PI3K/AKT, and knockdown of either SIRT1 or the PI3K/Akt inhibitor (LY294002) abolished the effect of miR-138-5p on NP cell apoptosis. Together, these results indicate that miR-138-5p is a novel regulator of human NP cell apoptosis induced by TNF-α. The knockout of miR-138-5p expression protected human NP cells from apoptosis via the upregulation of SIRT1, which was possibly mediated via PTEN/PI3K/Akt signaling. These findings suggest that the miR-138-5p/SIRT1/PTEN/PI3K/Akt signaling pathway might represent a novel therapeutic target for the prevention of IDD.

Downregulation of microRNA-193a-3p is involved in invertebral disc degeneration by targeting MMP14

Accumulating evidence suggests that microRNAs (miRNAs) play an important role in intervertebral disc degeneration (IDD), but the precise role of specific miRNAs involved in this disease remains elusive. The purpose of this study was to identify IDD-specific miRNAs, followed by functional validation of results. MiRNA expression profile was determined in nucleus pulposus (NP) tissues from patients with IDD and controls, employing Solexa sequencing and quantitative real-time PCR (qRT-PCR). Biological functions of differential expression miRNAs were further investigated in vitro and in vivo. Luciferase reporter assays and Western blotting were performed to determine miRNA targets. We identified 28 miRNAs that were differentially expressed in patients compared with controls. Following qRT-PCR confirmation, miR-193a-3p was significantly down-regulated in degenerative NP tissues. Moreover, its level was correlated with grade of disc degeneration. Through gain- and loss-of-function studies, miR-193a-3p was demonstrated to significantly promote type II collagen expression in NP cells. Knockdown of MMP14 induced effects on NP cells similar to those induced by miR-193a-3p. Bioinformatics target prediction identified MMP14 as a putative target of miR-193a-3p. Furthermore, luciferase reporter assays and Western blotting demonstrated that miR-193a-3p directly targets MMP14. MiR-193a-3p inhibited IDD in vitro and in vivo. The downregulation of miR-193a-3p induces the expression of MMP14, which promotes loss of type II collagen and thereby contributes to the development of human IDD. Our findings extend the role of miR-193a-3p in the pathogenesis of IDD and provide a potential novel therapeutic target for degenerative disc disease.

KEY MESSAGES

Intervertebral disc degeneration (ICC)-specific miRNA profile generated by next generation sequencing. Downregulation of miR-193a-3p promoted loss of type II collagen by directly targeting MMP14 in IDD. miR-193a-3p inhibited IDD in vitro and in vivo. miR-193a-3p may be a promising candidate for prevention of degenerative disc disease.

The Role of MicroRNAS in Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a common and genetically heterozygous inflammatory rheumatic disease characterized by new bone formation, ankylosis and inflammation of hip, sacroiliac joints and spine. Until now, there is no method for early diagnosis of AS and the effective treatment available for AS patients remain largely undefined.We searched articles indexed in PubMed (MEDLINE) database using Medical Subject Heading (MeSH) or Title/Abstract words ("microRNA" and "ankylosing spondylitis") from inception up to November 2015.Genetic polymorphisms of miRNAs and their targets might alter the risk of AS development whereas certain miRNAs exhibit correlation with inflammatory index.Let-7i and miR-124 were upregulated whereas miR-130a was downregulated in circulating immune cells of AS patients. These deregulated miRNAs could modulate key immune cell functions, such as cytokine response and T-cell survival.miRNA deregulation is key to AS pathogenesis. However, clinical utilization of miRNAs for management of AS patients requires further support from future translational studies.

Dysregulated miR-98 Contributes to Extracellular Matrix Degradation by Targeting IL-6/STAT3 Signaling Pathway in Human Intervertebral Disc Degeneration

Intervertebral disc degeneration (IDD) is associated with dysregulated expression of microRNAs (miRNAs). However, the precise molecular mechanisms underlying this disorder remain unclear. Therefore, we tested the hypothesis that miRNAs modulate IDD through effects on the IL-6/STAT3 signaling pathway, a potential regulator of IDD. The miRNA expression profile was determined in nucleus pulposus (NP) tissues from patients with IDD and controls, employing miRNA microarray and quantitative real-time PCR (RT-qPCR). Biological functions of differential expression miRNAs were further investigated using immunofluorescent staining. Luciferase reporter assays and Western blotting were performed to determine miRNA targets. We identified 41 miRNAs that were differentially expressed in patients compared with controls. Following RT-qPCR confirmation, miR-98 was significantly downregulated in degenerative NP tissues. Moreover, its level was inversely correlated with grade of disc degeneration. Through gain-of-function and loss-of-function studies, miR-98 was shown to significantly promote type II collagen expression in NP cells. Interleukin-6 (IL-6) was identified as a target of miR-98. Knockdown of IL-6 induced effects on NP cells similar to those induced by miR-98. In contrast, IL-6 treatment abrogated the effects induced by miR-98 upregulation. Moreover, miR-98 dramatically suppressed expression of STAT3 target gene, MMP2. IL-6 treatment antagonized this effect, whereas knockdown of IL-6 by IL-6 short hairpin RNA (shIL-6) induced inhibitory effects on the expression of p-STAT3 and its main target genes, similar to miR-98. The mRNA level of IL-6 was inversely correlated with that of miR-98 in degenerative NP tissues. These results suggest the downregulation of miR-98 could promote IDD through the IL-6/STAT3 signaling pathway. Our findings also highlight miR-98 as a novel hopeful therapeutic target for IDD.