HOX Transcript Antisense Intergenic RNA Research Articles

An amplification-free method for the detection of HOTAIR long non-coding RNA

The discovery of large transcripts of long RNAs that have limited protein coding capacity, known as long non-coding RNAs (lncRNAs) present new concepts on RNA-mediated gene regulation. Increasing evidence suggests that large intervening ncRNAs regulate key pathways in cancer genesis and metastasis. Among the most characterized lncRNAs, homeobox (HOX) transcript antisense intergenic RNA (HOTAIR) acts as an oncogenic molecule in different cancer cells, and thus its expression level serves as a potential biomarker for diagnostic and therapeutic purposes in several human cancers, such as breast, prostate, liver and ovarian cancer. This paper reports a simple and sensitive sensor platform for the detection of HOTAIR. Extracted HOTAIR sequences from ovarian cancer cells and plasma samples derived from ovarian cancer patients were magnetically isolated and purified, followed by a sandwich hybridization event at a screen-printed gold electrode. This event was monitored by amperometry using the hydrogen peroxide/horseradish peroxidase/hydroquinone (H2O2/HRP/HQ) system. The catalytic enhancement of the amperometric signal enabled our assay to achieve a detection limit of 1.0 fM with a good inter-assay reproducibility (relative standard deviation (%RSD) = < 5.0%, n = 3). The method was used for the analysis of specific HOTAIR in cell line and a small cohort of plasma samples derived from patients with ovarian cancer. The analytical performance of the method was also demonstrated using a standard RT-qPCR. We believe that the proof of the concept assay demonstrated here could be a cost-effective alternative platform for screening cancer-related lncRNAs in routine clinical settings.

Exosome-Mediated Transfer of Long Noncoding RNA HOTAIR Regulates Temozolomide Resistance by miR-519a-3p/RRM1 Axis in Glioblastoma.

Background: Chemoresistance obstructs the treatment of glioblastoma (GB). Exosome-mediated transfer of long noncoding RNAs (lncRNAs) was reported to regulate chemoresistance in diverse cancers. The authors aimed to investigate the underlying mechanism of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) in regulating temozolomide (TMZ) resistance in GB. Materials and Methods: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was utilized to check TMZ resistance and cell proliferation. The abilities of cell migration and invasion were evaluated by transwell assay. The protein levels of E-cadherin, N-cadherin, Vimentin, CD63, CD81, and ribonucleoside-diphosphate reductase subunit M1 (RRM1) were measured by western blot. Quantitative real-time polymerase chain reaction was conducted to detect the levels of HOTAIR, microRNA (miR)-519a-3p, and RRM1. The starBase was hired to predict the target sites between miR-519a-3p and HOTAIR or RRM1 and the dual-luciferase reporter assay was performed to verify the interaction. Xenograft tumor model was established to investigate the biological role of HOTAIR in vivo. Results: The high abilities of cell viability and metastasis were observed in TMZ-resistant GB cells. LncRNA HOTAIR was significantly upregulated in TMZ-resistant GB cells and its downregulation inhibited proliferation, migration, invasion, and epithelial/mesenchymal transition in TMZ-resistant GB cells. Further analysis indicated that exosomal lncRNA HOTAIR induced TMZ resistance and modulated TMZ resistance through miR-519a-3p/RRM1 axis. Besides, serum exosomal lncRNA HOTAIR was stable and had diagnostic value. Moreover, knockdown of lncRNA HOTAIR reduced TMZ resistance in vivo. Conclusions: Exosomal lncRNA HOTAIR mediated TMZ resistance through miR-519a-3p/RRM1 axis in GB.

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.

Genetic association between HOTAIR gene and the risk of cancer: an updated meta-analysis

Several recent investigations show that HOX transcript antisense intergenic RNA (HOTAIR) play an important role in the pathogenesis of different cancers. HOTAIR polymorphisms has been widely studied in the context of association between with the risk of cancer pathogenesis. However, there is no certain conclusion about the role of HOTAIR polymorphisms in different cancer initiation and progression. Our team has selected eligible studies up to 1 May 2019, from several electronic databases, including Web of Science, PubMed, Scopus, and Google Scholar databases. We have included total number of 102 case-control investigations extracted from 41 eligible articles for the current meta-analysis. We calculated pooled odds ratio (ORs) with their corresponding 95% confidence intervals (CIs) using either fixed-effect or random-effect models for quantitative evaluation of the strength for the association between HOTAIR gene polymorphisms and the risk of cancer. Our current meta-analysis investigation showed that HOTAIR rs4759314 polymorphism particularly increased the overall risk of cancer in different models including homozygous, recessive and allele genetic. HOTAIR rs920778 significantly raised the cancer risk only in recessive genetic model. HOTAIR rs12826786 polymorphism was associated with cancer development in heterozygous, homozygous, dominant, recessive and allele genetic models. Also, an increase in cancer risk was observed with rs874945 polymorphism of HOTAIR gene in heterozygous, dominant and allele genetic models. The rs12427129 polymorphism showed correlation with cancer susceptibility only in recessive model. Subgroup analysis based on cancer type suggested that rs4759314 polymorphism significantly increased the risk of gastric and cervical cancers, and the rs920778 polymorphism increased the risk of gastrointestinal, cervical and gastric cancers. In summary, this study found that HOTAIR polymorphisms are significantly associated with cancer development.

HOTAIR drives autophagy in midbrain dopaminergic neurons in the substantia nigra compacta in a mouse model of Parkinson's disease by elevating NPTX2 via miR-221-3p binding.

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive cell loss, largely confined to mesencephalic dopamine neurons of the substantia nigra. This study investigated the functional relevance of the HOX transcript antisense intergenic RNA (HOTAIR)/microRNA-221-3 (miR-221-3p)/neuronal pentraxin II (NPTX2) axis in the process of dopaminergic neuron autophagy using PD mouse models. The PD mouse models were established by intraperitoneal injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine (MPTP), while PD cell model was constructed by pretreatment with 1-methyl-4-phenylpyridinium (MPP+). The expression of HOTAIR was then examined using RT-qPCR. In addition, the interactions between HOTAIR, miR-221-3p, and NPTX2 were detected through RIP and dual-luciferase reporter gene assays. CCK-8 assay was performed to measure cell viability, and the expression of autophagy-related genes was determined using Western blot analysis. HOTAIR was found to be significantly expressed in the substantia nigra compact tissues and MN9D cells following PD modeling. HOTAIR could bind to miR-221-3p and elevate the NPTX2 expression, which resulted in diminished cell viability and enhanced autophagy of dopaminergic neurons both in vitro and in vivo. In summary, down-regulation of HOTAIR could potentially inhibit the autophagy of dopaminergic neurons in the substantia nigra compacta in a mouse model of PD, thus saving the demise of dopaminergic neurons.

Roles of HOTAIR in lung cancer susceptibility and prognosis.

BackgroundLong noncoding (lncRNA) single‐nucleotide polymorphisms (SNPs) are associated with the susceptibility to the development of various malignant tumors. The aim of this study was to investigate the roles of HOX transcript antisense intergenic RNA (HOTAIR) and its SNPs in lung cancer.MethodsInitially, the expression of HOTAIR in different tumors was investigated using the online Gene Expression Profiling Interactive Analysis (GEPIA) resource. Three SNPs (rs920778, rs1899663, and rs4759314) of HOTAIR were identified using the MassArray system. Following this, the relationship between these SNPs and susceptibility to lung cancer was investigated.ResultsExpression of HOTAIR was found to increase in a variety of cancers, including nonsmall cell lung cancer (NSCLC). We found that the genotypes of these SNPs (rs920778, rs1899663, and rs4759314) were not significantly associated with lung cancer type, family history, lymph node metastasis, or lung cancer stage. In gender stratification, the results of rs920778 genotypes showed that, compared to genotype AA, the AG (OR = 0.344, 95% CI: 0.133–0.893, p = .028) and AG + GG (OR = 0.378, 95% CI: 0.153–0.932, p = .035) genotypes of rs920778 are protective factors against NSCLC in females. In smoking stratification, compared with AA of rs920778, the genotype AG + GG (OR = 0.507, 95% CI: 0.263–0.975, p = .042) was a protective factor against NSCLC in nonsmoking people. No statistical differences were observed in the classifications of rs1899663 and rs4759314 genotypes. Linkage disequilibrium analysis revealed a high linkage disequilibrium between the rs920778 and rs1899663 (D′ = 0.99, r 2 = .74), rs920778 and rs4759314 (D′ = 0.85, r 2 = .13), and rs1899663 and rs4759314 (D′ = 0.79, r 2 = .00).ConclusionOur study demonstrated that HOTAIR expression increased in NSCLC, and that the genotypes of rs920778 could be useful in the diagnosis and prognosis of lung cancer.

LncRNA HOTAIR Contributes to Sorafenib Resistance through Suppressing miR-217 in Hepatic Carcinoma.

Background Sorafenib is a multi-target kinase inhibitor that has been approved as a unique target drug for the treatment of advanced hepatocellular carcinoma (HCC). However, due to the frequent occurrence of drug resistance, its treatment efficacy is often limited. The aim of this study was to explore the function of HOX transcript antisense intergenic RNA (HOTAIR) for the treatment of HCC with sorafenib, and its underlying mechanism. Methods A cell counting kit-8 (CCK-8) assay and Edu assay were used to examine the viability and proliferation of HCC cells. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of HOTAIR and miR-217 in HCC cells. Small interfering (si) RNA was transfected to knockdown HOTAIR to explore its biological function. A Western blot and immunofluorescence were performed to detect the level of E-cadherin and Vimentin expression. Results Sorafenib resistance was increased in HCC cells with high HOTAIR expression. Moreover, a knockdown of HOTAIR could improve the therapeutic effect of sorafenib on HCC via increasing E-cadherin and decreasing Vimentin expression. Additionally, a HOTAIR knockdown could increase the sensitivity of sorafenib for HCC treatment by up-regulating miR-217. Conclusions Lnc HOTAIR could increase sorafenib resistance in HCC by inhibiting miR-217. Our research attempts to elucidate a more effective treatment and provides novel insight into potential clinical treatment for HCC.

Long Non-Coding RNA HOTAIR in Breast Cancer Therapy.

Breast cancer (BC) is the most common cancer type among women, and morbidity and mortality rates are still very high. Despite new innovative therapeutic approaches for all BC molecular subtypes, the discovery of new molecular biomarkers involved in tumor progression has been fundamental for the implementation of personalized treatment strategies and improvement of patient management. Many experimental studies indicate that long non-coding RNAs (lncRNAs) are strongly involved in BC initiation, metastatic progression, and drug resistance. In particular, aberrant expression of HOX transcript antisense intergenic RNA (HOTAIR) lncRNA plays an important role in BC contributing to its progression and represents a predictor of BC metastasis. For its proven prognostic value, HOTAIR could represent a potential therapeutic target in BC. In the present review, we summarize the role of HOTAIR in cancer progression and drug resistance, in particular in BC, and we illustrate the main approaches for silencing it.

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.

The Long Noncoding RNA Hotair Regulates Oxidative Stress and Cardiac Myocyte Apoptosis during Ischemia-Reperfusion Injury.

Oxidative stress and subsequent cardiac myocyte apoptosis play central roles in the initiation and progression of myocardial ischemia-reperfusion (I/R) injury. Homeobox transcript antisense intergenic RNA (Hotair) was previously implicated in various heart diseases, yet its role in myocardial I/R injury has not been clearly demonstrated. Mice with cardiac-restricted knockdown or overexpression of Hotair were exposed to I/R surgery. H9c2 cells were cultured and subjected to hypoxia/reoxygenation (H/R) stimulation to further verify the role and underlying mechanisms of Hotair in vitro. Histological examination, molecular detection, and functional parameters were determined in vivo and in vitro. In response to I/R or H/R treatment, Hotair expression was increased in a bromodomain-containing protein 4-dependent manner. Cardiac-restricted knockdown of Hotair exacerbated, whereas Hotair overexpression prevented I/R-induced oxidative stress, cardiac myocyte apoptosis, and cardiac dysfunction. Mechanistically, we observed that Hotair exerted its beneficial effects via activating AMP-activated protein kinase alpha (AMPKα). Further detection revealed that Hotair activated AMPKα through regulating the enhancer of zeste homolog 2/microRNA-451/calcium-binding protein 39 (EZH2/miR-451/Cab39) axis. We provide the evidence that endogenous lncRNA Hotair is an essential negative regulator for oxidative stress and cardiac myocyte apoptosis in myocardial I/R injury, which is dependent on AMPKα activation via the EZH2/miR-451/Cab39 axis.

Long non-coding RNA HOTAIR and HOTTIP as potential biomarkers for hepatitis C virus genotype 4-induced hepatocellular carcinoma

BackgroundLong non-coding RNAs (lncRNAs) homeobox (Hox) transcript antisense intergenic RNA (HOTAIR) and HOXA transcript at the distal tip (HOTTIP) have been suggested to be implicated in liver cancer tumorigenesis and progression; however, little is known about the role of the plasma HOTAIR and HOTTIP in liver cancer diagnosis and prognosis. The current study aimed at measuring the plasma levels of long non-coding RNAs (HOTAIR and HOTTIP) expression in chronic liver disease (CLD) due to HCV genotype 4 infection with/without cirrhosis and HCC patients in an attempt to evaluate the potential benefits of these new circulating as non-invasive diagnostic biomarkers and a novel therapeutic strategy for liver cirrhosis and carcinogenesis of Egyptian patients. Hundred subjects were included in this study, divided into two groups; group I (50 patients) were classified into subgroup Ia (CLD without cirrhosis, n = 25) and subgroup Ib (CLD with cirrhosis, n = 25), group II (CLD patients with HCC, n = 25), and control (healthy volunteer, n = 25). The expression of lncRNAs (HOTAIR and HOTTIP) genes was analyzed by real-time PCR.ResultsLncRNAs (HOTAIR and HOTTIP) showed upregulation in all diseased groups, which was in consistent with the progression of the disease toward the HCC stage. In addition, HOTAIR and HOTTIP showed a diagnostic ability to discriminate between cases of cirrhosis and HCC compared with healthy control (p < 0.001), while HOTAIR and HOTTIP did not show a discrimination significant differences between cirrhotic cases and non-cirrhotic cases. By using receiver operating characteristic curve (ROC) analysis, it was found that LncRNAs (HOTAIR and HOTTIP) could diagnose liver cancer with 64.0% sensitivity and 86.0% specificity and 48.0% sensitivity and 88.0% specificity. Furthermore, both genes can be considered as the predictor and prognostic parameters for cirrhosis (OR = 1.111, p = 0.05) and (OR = 1.07, p = 0.05) respectively, and HCC (OR = 1.047, p = 0.01) and (OR = 1.05, p = 0.003). The increased HOTAIR and HOTTIP expression were associated with advanced tumor stages and higher grades.ConclusionThese results strongly prompt us that HOTAIR and HOTTIP genes can be used as non-invasive prognostic biomarkers and new therapeutic targets for HCV genotype 4-induced HCC.

Prognostic Value of LncRNA HOTAIR in Colorectal Cancer: A Meta-analysis.

: HOX transcript antisense intergenic RNA (HOTAIR) is one of the most studied long noncoding RNAs (lncRNAs) and is aberrantly expressed in colorectal cancer (CRC). We thus performed a comprehensive study based on meta-analysis and validation of the TCGA database to investigate clinicopathological and prognostic value of HOTAIR in CRC. Six studies enrolling 629 CRC patients were included in the analysis. The results indicated that high HOTAIR expression predicted worse OS (hazard ratio [HR] = 2.46, 95% confidence interval [CI]: 1.82-3.32, P < 0.01) and RFS (HR = 1.97, 95% CI: 1.27-3.05, P < 0.01) for CRC patients. High HOTAIR expression was also significantly associated with venous invasion (OR = 2.53, 95% CI: 1.12-5.68, P = 0.02), advanced tumor infiltration (OR = 3.35, 95% CI: 1.34-8.42, P = 0.01) and distant metastasis (OR = 5.52, 95% CI: 1.22-25.01, P = 0.03). Then, the results were validated by the TCGA database, showing that the up-regulated expression of HOTAIR was significantly related to poor OS (P = 0.01) and RFS (P = 0.04) in CRC. Our meta-analysis indicated that high HOTAIR expression was closely associated with poor clinical outcomes and could be a reliable prognostic biomarker for CRC patients.

Association Analysis Between the rs1899663 Polymorphism of HOTAIR and Risk of Psychiatric Conditions in an Iranian Population

Recent studies have shown contribution of long non-coding RNAs (lncRNAs) in the pathogenesis of a number of psychiatric disorders. In the current study, we investigated the association between a single nucleotide polymorphism in the lncRNA HOX transcript antisense intergenic RNA (HOTAIR) and risk of diverse neuropsychiatric conditions in Iranian population. The selected polymorphism (rs1899663) is an intronic variant of this lncRNA which has been associated with several cancers in different populations. This SNP was genotyped in 323 individuals with methamphetamine addiction, 55 children with attention-deficit hyperactive disorder (ADHD), 138 patients with bipolar disorder 1 (BPD1), 86 patients with BPD2, 53 patients with major depressive disorder (MDD), and 194 patients with schizophrenia (SCZ). There was no significant association between rs1899663 genotypes and risk of methamphetamine addiction or SCZ in any assessed inheritance model. There was a significant association between rs1899663 SNP and risk of BPD1 in allelic, co-dominant, and dominant models (P values of 0.003, 0.009, and 0.003, respectively). The T allele of this SNP conferred risk of BPD1 (OR (95% CI) = 1.70 (1.20-2.41)). This SNP was associated with risk of BPD2 in allelic and dominant models (P values of 0.02 and 0.04). The T allele of this SNP was revealed to be the risk allele for BPD2 as well (OR (95% CI) = 1.61 (1.09-2.40)). Besides, the mentioned SNP was associated with susceptibility to MDD in allelic and dominant models (P values of 0.01 and 0.03). Finally, the rs1899663 was associated with risk of ADHD in allelic, co-dominant, and dominant models (P values of 3.6E-4, 0.002, and 1.2E-4, respectively). The current investigation highlights the role of rs1899663 in conferring risk of BPD1, BPD2, MDD, and ADHD and suggests a similar underlying genetic background for these conditions.

Diagnostic roles of HOX transcript antisense intergenic RNA in cancer.

HOX transcript antisense intergenic RNA (HOTAIR) is considered a diagnostic biomarker for cancer; however, results of previous studies on HOTAIR are inconsistent. In this meta-analysis, we aimed to investigate the role of HOTAIR in cancer diagnosis. Medline, PubMed, Embase, Ovid, Web of Science and Cochrane databases were searched for relevant literature up to May 2019. Over all, we included 20 studies from 17 articles on the role of HOTAIR in cancer diagnosis (individual diagnosis) and 7 studies from 6 articles on the role of HOTAIR along with other biomarkers in cancer diagnosis (combinative diagnosis). The sensitivity and specificity of HOTAIR-mediated individual diagnosis of cancers were 0.80 (95% confidence interval [CI],0.74-0.85) and 0.74 (95% CI,0.66-0.81), respectively. The sensitivity and specificity of HOTAIR-mediated combinative diagnosis of cancer were 0.82 (95% CI,0.77-0.87) and 0.86 (95% CI,0.80-0.91), respectively. The areas under the receiver operating characteristic curve for individual and combinative diagnoses was 0.84 (95% CI,0.81-0.87) and 0.91 (95% CI,0.88-0.93), respectively, indicating that a combinative diagnosis has a relatively better diagnostic accuracy (z=-2.22, P=0.01) than individual diagnosis. In conclusion, HOTAIR levels might be a promising biomarker in cancer diagnosis. In addition, using HOTAIR in combination with other biomarkers showed a relatively better diagnostic accuracy than HOTAIR alone.

The rs4759314 SNP within Hotair lncRNA is associated with risk of multiple sclerosis

Recent studies have demonstrated the role of long non-coding RNAs (lncRNAs) in the pathophysiology of autoimmune disorders such as multiple sclerosis (MS). Among these transcripts is HOX transcript antisense intergenic RNA (HOTAIR) whose contribution in MS has been verified both in animal models and in human studies. In the current study, we genotyped three single nucleotide polymorphisms (SNPs) with this lncRNA (rs12826786, rs1899663 and rs4759314) in 403 Iranian MS patients and 420 healthy subjects. After correction of P values for multiple comparisons, the rs4759314 SNP was associated with risk of MS in allelic model (OR (95% CI)= 1.34 (1.08–1.67), adjusted P value=0.02). The other SNPs were not associated with risk of MS in any inheritance model. The C G A haplotype (rs12826786, rs1899663 and rs4759314, respectively) was less prevalent in cases compared with controls (OR (95% CI)= 0.73 (0.59–0.90), adjusted P value=0.03). The T G A haplotype was more common among cases compared with controls (OR (95% CI)= 1.58 (1.20–2.08), adjusted P value=0.01). Taken together, HOTAIR might be regarded as a risk locus for MS in Iranian population.

Down-regulation of long non-coding RNA HOTAIR promotes angiogenesis via regulating miR-126/SCEL pathways in burn wound healing

miR-126, an endothelial-specific microRNA, is associated to vascular integrity and angiogenesis. It is well established that angiogenesis plays a critical role in burn wound healing. However, there was a lack of understanding of the mechanism by which miR-126 regulates angiogenesis during burn wound healing. HOX transcript antisense intergenic RNA (HOTAIR) is a well-characterized long non-coding RNA (lncRNA) involved in cell proliferation, apoptosis, migration, and invasion of cancer cells. Sciellin (SCEL), a precursor to the cornified envelope of human keratinocytes, has been shown to inhibit migration and invasion capabilities of colorectal cancer cells. In this study, a cohort of 20 burn wound tissues and paired adjacent normal tissues were collected. LncRNA and messenger RNA expression profiles were screened by microarray analysis in five pairs of samples with mostly increased miR-126 levels. miR-126 was highly expressed in burn wound tissues and human umbilical vein endothelial cells (HUVECs) exposed to heat stress, whereas HOTAIR and SCEL were down-regulated after thermal injury. Bioinformatic analysis, dual luciferase reporter assay, and quantitative real-time PCR were conducted to validate that HOTAIR and SCEL competitively bind to miR-126 to function as the competitive endogenous RNA. miR-126 promoted endothelial cell proliferation, migration, and angiogenesis, but suppressed apoptosis, while HOTAIR and SCEL exerted opposite effects in HUVECs. The biological functions were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, Annexin-V-FITC/PI (propidium iodide/fluorescein isothiocyanate) staining, transwell migration, and tube formation assays. Collectively, our study revealed that HOTAIR/miR-126/SCEL axis contributes to burn wound healing through mediating angiogenesis.

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.

Effects of lncRNA HOTAIR on proliferation and apoptosis of myeloma cells through NF-κB pathway.

The aim of this study was to explore the influences of long non-coding ribonucleic acid (lncRNA) homeobox transcript antisense intergenic RNA (HOTAIR) on the proliferation and apoptosis of myeloma cells and its molecular mechanism. The myeloma cells were randomly divided into three groups, including: group A (myeloma cell group), group B [HOTAIR-small-interfering RNA (siRNA) group], and group C (HOTAIR negative control group). The Reverse Transcription-Polymerase Chain Reaction (RT-PCR) was performed to detect the expression of lncRNA HOTAIR in myeloma cells. The flow cytometry was adopted to determine the apoptosis of myeloma cells. Meanwhile, the protein expression of nuclear factor-kappa-light-chain-enhancer of activated B cells (NF-κB) was detected via Western blotting. In addition, the activity of the myeloma cells was measured using methyl thiazolyl tetrazolium (MTT) assay. The expression of HOTAIR in group A, group B, and group C was (2.19 ± 0.33), (1.37 ± 0.25), and (2.51 ± 0.27), respectively. Compared with group A and group C, the expression of HOTAIR was significantly downregulated in group B, in which the cells interfered with siRNAs. The expression of HOTAIR was significantly higher in group C than group A and group B (p<0.05). HOTAIR expression reached the highest level in group C, followed by group A and group B, respectively. The results of MTT indicated that the activity of the myeloma cells significantly increased at 24 h, 48 h, and 72 h in group C when compared with group A and group B. However, the activity of the myeloma cells was relatively low in group B, showing a slow rising trend. The activity of myeloma cells in group A remarkably increased when compared with group B, but it was lower than group C. Furthermore, the activity of the myeloma cells was higher in group C than group B (p<0.05). Western blotting indicated that the protein expression of NF-κB in group A, group B, and group C was (0.79 ± 0.22), (0.51 ± 0.17), and (0.95 ± 0.31), respectively. Compared with group A and group C, the protein expression of NF-κB was significantly downregulated in group B (the cells interfered with siRNAs) (p<0.05). Meanwhile, the protein expression of NF-κB was markedly higher in group C than in group A and group B (p<0.05). The protein expression of NF-κB was the highest in the cells of group C. Flow cytometry demonstrated that the apoptosis rate in group A, group B, and group C was (9.57 ± 1.71), (20.33 ± 1.63), and (8.74 ± 1.23), respectively. Compared with group A and group C, the apoptosis was significantly elevated in group B, in which the cells interfered with siRNAs (p<0.05). Compared with group A, the number of apoptotic myeloma cells significantly decreased in group C (p<0.05). LncRNA HOTAIR activates the expression of NF-κB in myeloma cells and promotes the proliferation of myeloma cells.

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.