Overexpression Of Hox Transcript Antisense Intergenic RNA Research Articles

LncRNA HOTAIR inhibits the progression of fibroblast-like synoviocytes by sponging miRNA-106b-5p in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic progressive autoimmune disease of unknown etiology. Human fibroblast-like synoviocytes (HFLSs) are the main effector cells for synovial hyperplasia and invasion in RA. Long non-coding RNAs (lncRNAs) play key roles in several autoimmune diseases, including RA. We investigated the effects of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) on the pathological behavior of HFLSs in RA. The microRNAs (miRNAs) with potential binding sites for lncRNA HOTAIR were predicted using Starbase v2.0. TargetScan (http://www.targetscan.org) was used to analyze the potential target genes of miR-106b-5p. The interactions were further verified using a dual-luciferase reporter assay. RNA and protein expression was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting. The proliferation, cell invasion and migration, and cell apoptosis of HFLSs in RA was detected by the 3-(4,5-dimethylthiazol)-2,5-diphenyl-tetrazolium bromide (MTT) assay, transwell assay, and flow cytometry (FCM). The dual luciferase reporter assay confirmed the interactions between lncRNA HOTAIR and miR-106b-5p and between miR-106b-5p and SMAD family member 7 (SMAD7). The qRT-PCR results indicated that the expression of lncRNA HOTAIR was markedly decreased and that of miR-106b-5p was markedly increased in HFLSs of RA. Cell proliferation, invasion, and migration of HFLSs were inhibited by lncRNA HOTAIR upregulation, and the expression of miR-106b-5p was negatively regulated by lncRNA HOTAIR in HFLSs. Apoptosis of HFLS cells was improved by the overexpression of lncRNA HOTAIR. All the effects of lncRNA HOTAIR upregulation on HFLSs were reversed after the overexpression of miR-106b-5p. Smad7 was identified as a target gene of miR-106b-5p, and the effects of downregulation of miR-106b-5p on HFLSs could be abolished by silencing Smad7. We found that lncRNA HOTAIR was significantly downregulated in the HFLSs of patients with RA. Moreover, lncRNA HOTAIR influenced cell growth, migration, invasion, and apoptosis in HFLSs through the miR-106b-5p/Smad7 axis.

Unique role for lncRNA HOTAIR in defining depot-specific gene expression patterns in human adipose-derived stem cells.

Accumulation of fat above the waist is an important risk factor in developing obesity-related comorbidities independently of BMI or total fat mass. Deciphering the gene regulatory programs of the adipose tissue precursor cells within upper body or abdominal (ABD) and lower body or gluteofemoral (GF) depots is important to understand their differential capacity for lipid accumulation, maturation, and disease risk. Previous studies identified the HOX transcript antisense intergenic RNA (HOTAIR) as a GF-specific lncRNA; however, its role in adipose tissue biology is still unclear. Using three different approaches (silencing of HOTAIR in GF human adipose-derived stem cells [GF hASCs], overexpression of HOTAIR in ABD hASCs, and ChIRP-seq) to localize HOTAIR binding in GF hASC chromatin, we found that HOTAIR binds and modulates expression, both positively and negatively, of genes involved in adipose tissue-specific pathways, including adipogenesis. We further demonstrate a direct interaction between HOTAIR and genes with high RNAPII binding in their gene bodies, especially at their 3' ends or transcription end sites. Computational analysis suggests HOTAIR binds preferentially to the 3' ends of genes containing predicted strong RNA-RNA interactions with HOTAIR. Together, these results reveal a unique function for HOTAIR in hASC depot-specific regulation of gene expression.

Aberrant overexpression of HOTAIR inhibits abdominal adipogenesis through remodelling of genome-wide DNA methylation and transcription

ObjectiveAbdominal adiposity is strongly associated with diabetic and cardiovascular comorbidities. The long noncoding RNA HOTAIR (HOX Transcript Antisense Intergenic RNA) is an important epigenetic regulator with fat depot-specific expression. Its functional roles and epigenetic regulation in abdominal adipogenesis remain uncertain. MethodsWe collected different fat depots from healthy, severely obese, and uraemic subjects to measure fat-depot specific gene expression and quantify regional adiposity via dual-energy X-ray absorptiometry (DXA). HOTAIR was overexpressed to evaluate its functional roles. Reduced representation bisulfite sequencing (RRBS), RNA-sequencing, real-time qPCR and RNA/chromatin immunoprecipitation were performed to analyse HOTAIR-mediated epigenetic regulation. ResultsA negative correlation between adipose tissue HOTAIR expression (arm or abdominal subcutaneous fat depots) and regional adiposity under the status of severe obesity or uraemia was observed. HOTAIR overexpression using human immortalized abdominal preadipocytes further revealed its anti-adipogenic effects. Integrative analysis of genome-wide DNA methylation by reduced representation bisulfite sequencing (RRBS) and gene expression was performed. Overall, the differentially methylated genes were functionally enriched for nervous system development, suggesting that HOTAIR may be epigenetically associated with cell lineage commitment. We specifically found that HOTAIR-mediated genes showed strong changes in both DNA methylation and gene expression during abdominal adipogenesis. We observed that two HOTAIR-repressed genes, SLITRK4 and PITPNC1, present an obesity-driven fat-depot specific expression pattern that is positively correlated with the central body fat distribution. ConclusionsOur study indicated that HOTAIR is a key regulator of abdominal adipogenesis via intricate DNA methylation and is likely to be associated with the transcriptional regulation of genes involved in nervous system development and lipid metabolism, such as SLITRK4 and PITPNC1.

Cangxitongbi capsules protect the articular cartilage in the rat knee through the long non-coding RNA HOTAIR/p38MAPK pathway.

BackgroundKnee osteoarthritis (KOA) is a leading cause of chronic pain and disability, and as such, it poses a significant economic burden. Traditional Chinese medicine (TCM), as well as complementary and alternative medicine, can offer safe and effective treatments for KOA. Cangxitongbi (CXTB) capsule is a Chinese patented medicine for KOA treatment and has a remarkable curative effect. This article evaluated the effects and mechanisms of CXTB in protecting joint cartilage in vivo.MethodsThe KOA model was constructed in rats using the modified Hulth method. CXTB (35 mg/kg) was administered intragastrically for 4 weeks. Hematoxylin and eosin (HE) staining of the knee articular were performed to evaluate the efficiency of CXTB. Western blot analysis, quantitative polymerase chain reaction (qPCR), and enzyme-linked immunosorbent assay (ELISA) were used to investigate the protective mechanisms of CXTB in joint cartilage.ResultsCXTB effectively improved the morphological structure of the cartilage and bone in the knee joint by enhancing autophagy and regulating the expression of related protease and inflammatory factors. Furthermore, CXTB downregulated the expression of the long non-coding RNA (lncRNA) Hox transcript antisense intergenic RNA (HOTAIR) and inhibited the activation of the p38MAPK pathway. Conversely, overexpression of lncRNA HOTAIR suppressed the protective effects of CXTB on the knee joint.ConclusionsCXTB capsules can protect the knee articular cartilage in rats through the lncRNA HOTAIR/p38MAPK pathway.

Knockdown of long non-coding RNA HOTAIR promotes bone marrow mesenchymal stem cell differentiation by sponging microRNA miR-378g that inhibits nicotinamide N-methyltransferase

ABSTRACT Osteoporosis (OP) is associated with a serious social and economic burden. Recent studies have shown that the differential expression of long non-coding RNAs (lncRNAs) is closely related to OP. However, the specific molecular mechanism of HOX transcript antisense intergenic RNA (HOTAIR) remains to be elucidated. The expression of HOTAIR and miR-378g in OP patients was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). Bone marrow mesenchymal stem cells (BMSCs) were isolated and cultured, and osteogenic differentiation was induced. Alkaline phosphatase (ALP) and Runt-related transcription factor 2 (RUNX2) were detected by qRT-PCR, ELISA, and Western blotting. Calcium deposition was measured using Alizarin red s (ARS) staining. Molecular interactions between HOTAIR, miR-378g, and nicotinamide N-methyltransferase (NNMT) were detected using a dual-luciferase reporter assay. HOTAIR expression was upregulated and miR-378g level was downregulated in OP patients. HOTAIR expression decreased during the osteogenic differentiation of BMSCs. Silencing HOTAIR or NNMT reduced ALP and RUNX2 levels and promoted calcium deposition. The overexpression of HOTAIR or interference with miR-378g inhibited the osteogenic differentiation of BMSCs. HOTAIR negatively regulates miR-378g by targeting NNMT. HOTAIR is an miR-378g sponge that targets NNMT, inhibits the osteogenic differentiation of BMSCs, and provides a valuable target for the treatment of OP.

HOTAIR Modulated Pathways in Early-Stage Breast Cancer Progression.

The long-non-coding HOX transcript antisense intergenic RNA (HOTAIR) was identified as significantly upregulated in breast ductal carcinoma in situ (DCIS). The aim of this study was to characterize the phenotypic effects and signaling pathways modulated by HOTAIR in early-stage breast cancer progression. We determined that HOTAIR induces premalignant phenotypic changes by increasing cell proliferation, migration, invasion and in vivo growth in normal and DCIS breast cell lines. Transcriptomic studies (RNA-seq) identified the main signaling pathways modulated by HOTAIR which include bioprocesses related to epithelial to mesenchymal transition, cell migration, extracellular matrix remodeling and activation of several signaling pathways (HIF1A, AP1 and FGFR). Similar pathways were identified as activated in primary invasive breast carcinomas with HOTAIR over-expression. We conclude that HOTAIR over-expression behaves as a positive regulator of cell growth and migration both in normal and DCIS breast cells involved with early-stage breast cancer progression.

HOTAIR promotes gefitinib resistance through modification of EZH2 and silencing p16 and p21 in non-small cell lung cancer

The long non-coding RNA Hox transcript antisense intergenic RNA (HOTAIR) plays a critical role in tumorigenesis as well as drug resistance in various cancers. However, the molecular mechanism by which HOTAIR induces gefitinib resistance in non-small cell lung cancer is to date unclear. In the present study, we revealed that HOTAIR is upregulated in gefitinib-resistant lung cancer cells and over-expression of HOTAIR enhances gefitinib resistance in lung cancer cells. In addition, the overexpression of HOTAIR promotes cell cycle progression through epigenetic regulation of EZH2/H3K27. Silencing of EZH2 by either siRNA or inhibitors sensitized the lung cancer cells to gefitinib. Inhibition of EZH2 induces expression of p16 and p21, whereas levels of CDK4, cyclinD1, E2F1, and LSD1 are significantly decreased in PC-9 cells overexpressing HOTAIR. ChIP-PCR experiments indicate that HOTAIR increases H3K27me3 recruitment to the promoter of p16 and p21 in PC-9 lung cancer cells overexpressing HOTAIR. In xenograft mouse models, overexpressing HOTAIR in lung cancer tissues decreased p16 and p21 proteins. Taken together, these data suggest that HOTAIR contributes to gefitinib resistance by regulating EZH2 and p16 and p21. Targeting HOTAIR may be a novel therapeutic strategy for treating gefitinib-resistance in non-small cell lung cancer.

HOTAIR Induces Methylation of PCDH10, a Tumor Suppressor Gene, by Regulating DNMT1 and Sponging with miR-148b in Gastric Adenocarcinoma.

PurposeHOX transcript antisense intergenic RNA (HOTAIR), as a long non-coding RNA, has been reported to regulate carcinogenesis by epigenetic mechanism in various cancers. Protocadherin 10 (PCDH10) is one of the well-known tumor suppressor genes, and is frequently methylated in gastric cancers (GC). We aimed to investigate the detailed pathway of how HOTAIR contributes to the target gene in gastric carcinogenesis.Materials and MethodsWe investigated the mechanism of HOTAIR on carcinogenesis and metastasis of GC. Methylation-specific PCR was performed to identify the interaction between HOTAIR and PCDH10. In addition, we investigated the interaction between miR-148b and HOTAIR by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay.ResultsThe expression of HOTAIR was significantly upregulated in GC tissues (p<0.05) and GC cell lines (p<0.01), while PCDH10 was downregulated in GC tissues (p<0.05). The knockdown of HOTAIR (si-HOTAIR1 and 2) significantly upregulated the mRNA/protein expression of PCDH10 and reduced the methylation of PCDH10 compared to the control in MKN 28 and MKN 74. Si-HOTAIR1 and 2 significantly reduced DNA methyltransferase 1 (DNMT1) expression, and overexpression of HOTAIR increased DNMT1 expression. In RIP, we found that miR-148b interacted with HOTAIR. Si-HOTAIRs increased miR-148b expression, and miR-148b mimic inversely reduced HOTAIR expression. Si-HOTAIRs and miR-148b mimic reduced DNMT1 expression and increased PCDH10 expression compared to the control.ConclusionThis study demonstrated that HOTAIR interacts with miR-148b and DNMT1, eventually leading to PCDH10 methylation, which contributes to the progression of GC. Our findings provide a better understanding for detailed pathway of HOTAIR in epigenetic mechanism of GC.

Investigating the effect of lncRNA HOTAIR on apoptosis induced by myocardial ischemia-reperfusion injury.

The present study aimed to investigate the effect of the long non-coding ribonucleic acid (lncRNA) HOX transcript antisense intergenic RNA (HOTAIR) on apoptosis induced by ischemia-reperfusion injury. Differential lncRNAs in myocardial ischemia rats were screened by a lncRNA microarray and the expression levels of lncRNA HOTAIR and microRNA (miR)-130a-3p were analyzed using reverse transcription-quantitative polymerase chain reaction in hypoxia-induced cardiomyocytes. The mechanism of lncRNA HOTAIR in cardiotoxicity was investigated using cell transfection, lncRNA knockdown, Cell Counting Kit-8, flow cytometry, western blotting, dual luciferase reporter assays and RNA immunoprecipitation. The expression level of lncRNA HOTAIR was significantly downregulated in the ischemic myocardium of rats. Overexpression of HOTAIR in H9c2 (rat cardiomyocyte line) cells could inhibit the apoptosis induced by H2O2. A direct interaction was found between HOTAIR and miR-130a-3p, and mouse double minute 4 (MDM4) was also found to be a potential target of miR-130a-3p. The overexpression of MDM4 in H9c2 cells transfected with miR-130a-3p mimics increased apoptosis, and miR-130a-3p targeted inhibition of MDM4 promoted H2O2-induced apoptosis of H9c2 cells. Overall, HOTAIR was found to inhibit the apoptosis of H9c2 cells induced by H2O2 through the miR-130a-3p/MDM4 axis.

Co-expression of HOTAIR long noncoding RNA and Tbx3 transcription factor in breast cancer tissues

BackgroundBreast cancer (BC) is one of the most prevalent neoplasia worldwide. Long noncoding RNAs (lncRNAs) have potential regulatory roles in different cancers. The aim of this study was to investigate the possible correlation between HOTAIR (Hox transcript antisense intergenic RNA) and TBX3 (T-box transcription factor 3) expressions as both are located at Chromosome 12, as two known BC biomarkers. MethodsQuantitative real-time PCR (polymerase chain reaction) was used to assess the expression levels of TBX3 and HOTAIR on 25 pair of tumor-normal breast tissues from BC patients. In silico tools were utilized to determine putative miRNAs targeting TBX3 as well as miRNAs targeted by HOTAIR lncRNA. ResultsStatistical analysis showed significant tissue overexpression of HOTAIR and Tbx3 in BC patients compared with the control samples (p = 0.001 and 0.042 respectively). Pearson analysis showed that the expression profiles of HOTAIR and TBX3 were correlated in these patients (p = 0.015). Binary regression logistic analysis revealed the potential use of the combination of TBX3 and HOTAIR expression as an independent diagnostic factor (p = 0.02 and 0.04, respectively) in BC patients. In silico analysis revealed eight common miRNAs between HOTAIR and Tbx3. ConclusionResults indicated correlated overexpression levels of both HOTAIR and TBX3 in breast tissues of BC patients. Moreover, bioinformatics data showed a possible mediatory role for miRNAs between HOTAIR and TBX3 RNA levels, which may possibly contribute to the development of cancer.

Overexpression of HOTAIR in Tumor Tissues of Patients with Colon Cancer Correlates with Tumor Metastasis and Differentiation

Background: Aberrant expression level of Hox transcript antisense intergenic RNA (HOTAIR) has been associated with the etiopathogenesis of numerous cancers. Studies on epidemiological data have demonstrated that the risk of susceptibility to colon cancer varies among different populations due to several reasons. In this study, we aimed to assess the expression level of HOTAIR in tumoral tissues of patients with colon cancer and compare it with normal marginal tissues. Methods: We recruited a total of 50 patients with colon cancer and collected tumoral and matched marginal tumor free tissues during surgery. Afterwards, we isolated the total RNA from each sample, synthesized cDNA, and performed quantitative analysis by Real-time PCR using the SYBR Green PCR Master Mix in order to measure the transcript level of HOTAIR in samples. Results: The expression level of HOTAIR was upregulated in tumor tissues compared with normal tumor-free marginal tissues belonging to colon cancer patients (P= 0.0023). Moreover, the expression level of HOTAIR and the clinicopathological specifications of the patients had statistically significant correlations. Conclusions: HOTAIR may play a role in the development of colon cancer and have the potential for application as a biomarker for colon cancer prognosis.

Long-chain non-coding RNA HOTAIR promotes the progression of osteoarthritis via sponging miR-20b/PTEN axis

AimsCumulative evidence suggests that long-chain non-coding RNA (lncRNA) is involved in the pathogenesis of osteoarthritis (OA). The present study aimed to explore the regulatory role and related mechanisms of HOX transcript antisense intergenic RNA (HOTAIR) in OA. Material and methodsThe OA mouse model was constructed by the medial meniscus (DMM) method, and Interleukin (IL)-1β-induced chondrocytes were used to simulate OA in vitro. Key findingsResults found that HOTAIR was significantly up-regulated in articular cartilage tissues of OA mice and IL-1β-induced chondrocytes, accompanied by down-regulation of miR-20b and increased expression of the phosphatase and tensin homolog (PTEN). HOTAIR silencing improved cartilage tissue damage in OA mice, and promoted the expression of collagen II and aggrecan in cartilage tissue, while inhibited the expression of matrix metalloproteinases (MMP)-13 and ADAMTS-5. Overexpression of HOTAIR inhibited the proliferation of IL-1β-induced chondrocytes and promoted apoptosis and extracellular matrix (ECM) degradation, whereas the effect of HOTAIR knockdown was reversed. Bioinformatics software and luciferase reporter experiments confirmed that HOTAIR could negatively regulate miR-20b, and PTEN was a target gene of miR-20b. An increase in PTEN expression induced by HOTAIR overexpression could be reversed by the introduction of miR-20b mimic. HOTAIR overexpression significantly reversed miR-20 mimic-mediated inhibition of apoptosis and ECM degradation in IL-1β-induced chondrocytes, whereas the introduction of si-HOTAIR eliminated anti-miR-20b-mediated apoptosis and ECM degradation. SignificanceHOTAIR can participate in OA by promoting chondrocyte apoptosis and ECM degradation, which may be related to its targeted regulation of miR-20b/PTEN axis.

HOTAIR‐induced apoptosis is mediated by sponging miR‐130a‐3p to repress chondrocyte autophagy in knee osteoarthritis

Knee osteoarthritis (KOA) is a multifactorial disease characterized by the loss of articular cartilage. Hox transcript antisense intergenic RNA (HOTAIR) long non-coding RNA (lncRNA) is highly expressed in some cases of OA; however, its role in chondrocyte apoptosis in KOA and the mechanism by which HOTAIR mediates apoptosis in chondrocytes are not completely understood. Here, we evaluated the effects of HOTAIR on chondrocyte apoptosis in KOA. Our results showed that HOTAIR expression was significantly upregulated in cartilage tissues located at the femoral condyles or tibial plateaus of OA resection regions when compared with control regions in patients with normal non-weight-bearing area femoral condyle articular cartilage. Overexpression of HOTAIR caused a sharp increase in apoptosis rates and a reduction in the viability of chondrocytes. These effects were accompanied by the upregulation of Bax expression and the proteolytic cleavage of caspase 3 expression and downregulation of survivin and Bcl-2 expression. The silencing of HOTAIR produced the opposite effects. Moreover, the cartilaginous expression of miR-130a-3p was notably reduced in the OA resection regions of KOA patients. Luciferase assays showed that HOTAIR-adsorbed and reduced the levels of miR-130a-3p in chondrocytes. Further, inhibition of miR-130a-3p remarkably promoted the apoptosis of chondrocytes and repressed cell growth, while the silencing of HOTAIR could rescue the apoptosis mediated by miR-130a-3p inhibition. Chondrocyte autophagy was suppressed in a HOTAIR-dependent, miR-130a-3p inhibitor-mediated manner. Overall, our data revealed that aberrantly high expression of HOTAIR resulted in massive apoptosis events caused by the sponging of miR-130a-3p to suppress autophagy in chondrocytes, which, in turn, might trigger KOA. Therefore, inhibition of HOTAIR-mediated apoptosis might be a potential mechanism that can be targeted by gene therapy of KOA.

HOTAIR regulates lipopolysaccharide-induced inflammatory response in hepatocytes.

It has been widely accepted that long-noncoding RNA (lncRNA) HOX transcript antisense intergenic RNA (HOTAIR) emerges as a crucial mediator in inflammation. Here, we first detected HOTAIR in lipopolysaccharide (LPS)-treated normal human liver cell line (L02) and hepatocellular carcinoma cell lines (C3A, HepG2, and SMMC-7721). Further, we explored the biological function of HOTAIR in LPS-induced hepatocytes (L02 and C3A) lesions and investigated the molecular mechanisms. Besides, we focused on inflammatory signaling crosstalk. The inflammatory insults were assayed by cell counting kit-8 (CCK-8), cell cycle and apoptosis analysis kit, and immunoblotting assay. HOTAIR level was examined by reverse-transcription polymerase chain reaction. To determine the effect of HOTAIR silence or overexpression in inflammation, we applied quantitative reverse-transcription polymerase chain reaction, immunoblotting assay, and enzyme-linked immuno sorbent assay. Regulator inhibitors of Janus kinase/signal transducer and activator of transcription (JAK2/STAT3; AG490) and nuclear factor κB (NF-κB; BAY-11-7082) were applied to treat cells. Our results suggested that LPS induced the overexpression of HOTAIR in L02, C3A, HepG2, and SMMC-7721 cells. LPS repressed viability, induced apoptosis, and facilitated the expression of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in L02 and C3A cells. IL-1β, IL-6, and TNF-α were upregulated by HOTAIR overexpression while downregulated by HOTAIR knockdown in LPS-treated cells. We further observed that HOTAIR overexpression accelerated LPS-induced phosphorylation whereas HOTAIR silence blocked this progress. Inhibition of JAK/STAT and NF-κB contributed to the suppression of cytokines which was evoked by LPS. Collectively, our findings indicated that HOTAIR exerted a crucial role in cytokines expression by activating JAK/STAT and NF-κB.

HOTAIR alleviates ox-LDL-induced inflammatory response in Raw264.7 cells via inhibiting NF-κB pathway.

To investigate the possible role of hox transcript antisense intergenic RNA (HOTAIR) in the pathogenesis of atherosclerosis and its underlying mechanism. The expression of HOTAIR in peripheral blood lymphocytes of atherosclerosis (AS) and healthy controls was detected by quantitative Real-time-polymerase chain reaction (qRT-PCR). In vitro AS model was established by ox-LDL induction in Raw264.7 cells. Viability of Raw264.7 cells after ox-LDL induction was detected by cell counting kit-8 (CCK-8) assay. Levels of TC (total cholesterol), TG (triglyceride), LDL-C (low density lipoprotein cholesterol) and HDL-C (high density lipoprotein cholesterol) in Raw264.7 cells were detected by enzyme-linked immunosorbent assay (ELISA). Overexpression plasmid of HOTAIR was constructed. Levels of TG, TC, LDL-C, and HDL were detected again after HOTAIR overexpression by ELISA. CD68+ cells and CD168+ cells in Raw264.7 cells were detected by flow cytometry. Protein expressions of pro-inflammatory and anti-inflammatory genes were detected by Western blot. Lipid metabolism in Raw264.7 cells was evaluated by oil red O staining and Western blot, respectively. Finally, rescue experiments were conducted to explore the specific mechanism of HOTAIR in regulating AS development. HOTAIR was lowly expressed in peripheral blood lymphocytes of AS patients and Raw264.7 cells induced by ox-LDL. Overexpression of HOTAIR upregulated adipose genes (PPARα and CPT-1) and downregulated lipogenesis genes (SREBP-1c and ACS). Besides, overexpression of HOTAIR decreased expressions of pro-inflammatory cytokines (TNF-α and IL-1β), but increased expressions of anti-inflammatory cytokines (IL-4 and IL-10). In the in vitro AS model, FXR1 was remarkably downregulated in Raw264.7 cells. HOTAIR reduced inflammatory response via promoting FXR1 expression in Raw264.7 cells. Rescue experiments showed that the effect of HOTAIR on nuclear factor-kappa B (NF-κB) pathway was reversed by FXR1 knockdown. We found that TAIR was lowly expressed in AS patients. Overexpression of HOTAIR can reduce the lipid accumulation and inhibit inflammatory response by suppressing FXR1 via NF-κB pathway.

Long noncoding RNA HOTAIR promotes renal cell carcinoma malignancy through alpha-2, 8-sialyltransferase 4 by sponging microRNA-124.

Accumulating evidence demonstrated that the long noncoding RNA (lncRNA) HOTAIR (Hox transcript antisense intergenic RNA) plays key role in renal cell carcinoma (RCC) malignancy, while microRNA-124 (miR-124) is a tumour suppressor in RCC. The aim of this work was to assess the biological function of HOTAIR and to explore underlying mechanism involved in HOTAIR/miR-124/alpha-2, 8-sialyltransferase 4 (ST8SIA4) axis-regulated progression in RCC. Real-time PCR analyses and western blots were performed to the levels of HOTAIR, miR-124 and ST8SIA4 expression in human RCC tissues and RCC cell lines (ACHN and 786-O). Bioinformatics analysis and dual-luciferase reporter assay were used to illustrate relationship between HOTAIR and miR-124 in RCC. Colony formation assays, EdU assays, Ki67 assays and apoptosis assays were taken to evaluate cell proliferation. Tumour xenograft was created to explore the functions of HOTAIR and ST8SIA4 in tumorigenesis in vivo. Migration assays, invasion assays and cell adhesion assays and were also taken to analyse the carcinoma progression. In this study, HOTAIR level was confirmed to be significantly upregulated in RCC samples and RCC cell lines compared with those in the paired adjacent tissues and normal renal cell line. Overexpression of HOTAIR promoted the capability of proliferation, migration and invasion in RCC cell lines. HOTAIR directly bound to miR-124, while miR-124 mediated the expression of ST8SIA4 in RCC cell lines. ST8SIA4 was upregulated in RCC tissues and RCC cell lines. Ectopic expression of ST8SIA4 modulated the proliferation, migration and invasion of RCC cells. Further results indicated that HOTAIR promoted the proliferation and metastasis as a competing endogenous RNA to regulate ST8SIA4 expression by sponging miR-124 in RCC. Our results demonstrated that HOTAIR mediated RCC progression in part through miR-124/ST8SIA4 axis, which functioned as a new prognostic biomarker in RCC.

The long noncoding RNA HOTAIR promotes Parkinson’s disease by upregulating LRRK2 expression

Long noncoding RNAs (lncRNAs) have emerged recently as a new class of genes that regulate cellular processes. HOTAIR (Hox transcript antisense intergenic RNA), an approximately 2.2 kb long noncoding RNA transcribed from the HOXC locus, is upregulated in various diseases. However, the role of HOTAIR in Parkinson's disease (PD) remains unclear. A mouse model of PD was developed by intraperitoneal injection of MPTP. The expression of HOTAIR and LRRK2 were detected in the PD mice and in human neuroblastoma cell lines SH-SY5Y pretreated with MPP+. The effect of HOTAIR on the expression of LRRK2 was examined in SH-SY5Y cells through overexpressing or knockdown of HOTAIR. MTT and flow cytometry assay were performed to measure the cell viability and apoptosis of SH-SY5Y cells. We found that HOTAIR was up-regulated in midbrain tissue of MTPT induced PD mice and in SH-SY5Y cells exposed to MPP+. With the presence of HOTAIR overexpression in SH-SY5Y cells, the expression of LRRK2 was increased compared with that in the control. HOTAIR knockdown showed a protective effect on the cell viability of SH-SY5Y cells pretreated with MPP+. HOTAIR knockdown provided protection against MPP+-induced DA neuronal apoptosis by repressing caspase 3 activity. The finding that HOTAIR promoted PD induced by MPTP could add our understanding of the molecular mechanisms in PD. These findings suggested that inhibition of HOTAIR levels is an effective disease-modifying strategy in PD.

Prognostic value of lncRNA HOTAIR expression in patients with cancer: A Meta-analysis

To systematically review the prognostic value regarding the expression of long non-coding RNA (lncRNA) Hox transcript antisense intergenic RNA (HOTAIR) in patients with cancer. Methods: Databases including The Cochrane Library, EMBASE, MEDLINE, and PubMed were searched to collect English literature on the correlation between lncRNA HOTAIR expression and overall survival in tumors. The retrieval time was from inception to September 2015. After data were extracted, a Meta-analysis was performed using RevMan 5.3 software. Results: A total of 17 studies were included, which was involved in 1 639 patients. The Meta-analysis showed that high expression of HOTAIR could predict poor overall survival in cancer (HR: 2.39, 95% CI 2.01-2.86, P<0.001). High expression of HOTAIR could also predict poor overall survival both in digestive tumor (HR: 2.51, 95% CI 2.02-3.11, P<0.001) and non-digestive tumor (HR: 2.17, 95% CI 1.59-2.98, P<0.001). Moreover, overexpression of HOTAIR was found to be significantly associated with recurrence-free survival. Conclusion: The overexpression of lncRNA HOTAIR might be associated with poor prognosis in patients with cancer.

HOTAIR, a long non-coding RNA driver of malignancy whose expression is activated by FOXC1, negatively regulates miRNA-1 in hepatocellular carcinoma.

Evidence is rapidly accumulating that long non-coding RNAs (lncRNAs) are involved in human tumorigenesis and are dysregulated in multiple cancers, including hepatocellular carcinoma (HCC). lncRNAs can regulate essential pathways that contribute to tumor initiation and progression with tissue specificity, which suggests that lncRNAs may be valuable biomarkers and therapeutic targets. HOX transcript antisense intergenic RNA (HOTAIR) has previously been demonstrated to be an oncogene and a negative prognostic factor in a variety of cancers; however, the factors that contribute to the upregulation of HOTAIR and the interaction between HOTAIR and microRNAs (miRNAs or miRs) are largely unknown. In the present study, the expression levels of HOTAIR, forkhead box C1 (FOXC1) and miRNA-1 were examined in 50 matched pairs of HCC and HCC cells. The effects of HOTAIR on HCC cell proliferation were tested using trypan blue exclusion assay. The effect of HOTAIR on HCC growth in vivo was determined in a (nu/nu) mouse model. A computational screening of HOTAIR promoter was conducted to search for transcription factor-binding sites. FOXC1 binding to the promoter region of HOTAIR was confirmed using a chromatin immunoprecipitation assay. A search for miRNAs that had complementary base paring with HOTAIR was performed utilizing an online software program. The interaction between miR-1 and HOTAIR was examined using a luciferase reporter assay. Gain and loss of function approaches were used to determine the changes of HOTAIR or miR-1 expression. The relative levels of FOXC1 and HOTAIR expression in HCC tissues and HepG2 cells were significantly higher than those in normal liver LO2 cells and adjacent carcinoma tissues; the relative expression of miR-1 exhibited the opposite pattern. Overexpression of HOTAIR promoted HCC cell proliferation and progression of tumor xenografts. The present authors have demonstrated that FOXC1 binds to the upstream region of HOTAIR in HCC cells and that FOXC1 activates lncRNA HOTAIR expression in HCC HepG2 cells, which suggests that HOTAIR harbors a miRNA-1 binding site. The present data revealed that this binding site is vital for the regulation of miRNA-1 by HOTAIR. Furthermore, HOTAIR negatively regulated the expression of miRNA-1 in HepG2 cells. Additionally, the present study demonstrated that the oncogenic activity of HOTAIR is in part based on the negative regulation of miR-1. Taken together, these results suggest that HOTAIR is a FOXC1-activated driver of malignancy, which acts in part through the repression of miR-1.

Analysis of the association of HOTAIR single nucleotide polymorphism (rs920778) and risk of cervical cancer

We recently demonstrated that overexpression of HOTAIR (Hox transcript antisense intergenic RNA) was associated with tumor progression and radio-resistance in human cervical cancer. Considering the single nucleotide polymorphism (SNP) rs920778 (C>T) could influence HOTAIR expression and cancer predisposition in other malignancies, we herein investigated the association between rs920778 status and cervical cancer susceptibility in a Chinese population. Using the specific TaqMan PCR assay, we genotyped rs920778 in 215 cervical cancer patients and 430 age-matched healthy controls. As shown in our data, TT genotype of rs920778 was significantly correlated with the upregulation of HOTAIR (p=0.008). Compared with the healthy control, TT genotype and T allele notably indicated a much higher risk of cervical cancer [TT genotype: odds ratio (OR)=2.186, 95% confidence interval (CI)=1.378-3.466, p=0.003; T allele: OR=1.556, 95% CI=1.221-1.981]. In addition, we also found that the TT genotype of rs920778 was correlated with advanced tumor stage (p=0.039), highly histological grade (p=0.013), lympho node metastasis (p<0.001) and positive infection of high risk HPV (p<0.001). Among the patients who underwent concurrent chemo-radiotherapy, TT genotype carriers present notably resistance to the combination of EBRT+ICBT+cisplatin (p=0.023). In conclusion, we firstly reported that TT genotype of HOTAIR rs920778 was significantly associated with the cervical cancer susceptibility. Moreover, the TT genotype of rs920778 might be a potent prognostic marker in cervical cancer patients.