Expression Of HOX) Transcript Antisense RNA Research Articles

The lncRNA HOTAIR attenuates pyroptosis of diabetic cardiomyocytes by recruiting FUS to regulate SIRT3 expression.

Diabetic cardiomyopathy (DCM) is a serious cardiovascular complication of diabetes that severely affects the quality of life of diabetic patients. Long noncoding RNAs (lncRNAs) play important roles in the pathogenesis of DCM. However, the role of the lncRNA homeobox transcript antisense RNA (HOTAIR) in the progression of DCM remains unclear. The present study aimed to investigate the role of HOTAIR in high glucose (HG)-induced pyroptosis in cardiomyocytes. The expression of the lncRNA HOTAIR, FUS, and SIRT3 in H9C2 cardiomyocytes was detected by RT-qPCR. Western blotting was used to evaluate the expression of FUS and SIRT3 as well as that of pyroptosis- and inflammation-related proteins. RT-qPCR and ELISA were used to determine the expression and secretion of IL-1β and IL-18. RNA pulldown and RIP experiments were used to validate the binding relationship among HOTAIR, FUS, and SIRT3. Flow cytometry was performed to detect pyroptosis. HG induced pyroptosis and elevated the expression of proteins associated with pyroptosis and inflammation (NLRP3, GSDMD-N, cleaved caspase-1, IL-1β, and IL-18) in cardiomyocytes. HOTAIR and SIRT3 levels were decreased in HG-exposed H9C2 cells. Additionally, overexpression of HOTAIR inhibited the HG-induced pyroptosis and inflammatory response in cardiomyocytes. HOTAIR upregulated SIRT3 expression in H9C2 cells by targeting FUS. Moreover, SIRT3 upregulation suppressed HG-mediated pyroptosis of cardiomyocytes. Notably, SIRT3 depletion reversed the inhibitory effect of HOTAIR on HG-triggered pyroptosis in cardiomyocytes. Our research indicates that HOTAIR alleviates pyroptosis in diabetic cardiomyocytes through the FUS/SIRT3 axis, providing a potential marker for the diagnosis and treatment of DCM.

Long noncoding RNA HOTAIR and Midkine as biomarkers in thyroid cancer

Thyroid cancer is the most common endocrine malignancy, and its incidence is increasing. Differentiated thyroid cancer is the most common type and papillary thyroid carcinoma is the most common type of differentiated thyroid cancer. This work aimed to study long noncoding (Lnc) RNA homeobox transcript antisense RNA (HOTAIR) expression in plasma and serum midkine, a heparin binding growth factor, as biomarkers of thyroid cancer. This study included 27 thyroid cancer patients, 29 patients with benign thyroid disease and 26 individuals as normal controls. HOTAIR expression was assessed by real time polymerase chain reaction and midkine by ELISA. These biomarkers were elevated in thyroid cancer patients than patients with benign thyroid diseases and controls. Patients with thyroid cancer stage III had higher midkine levels in comparison to those with stage-I and stage-II (p < 0.001). Patients with grade II had higher midkine in comparison to those with grade I (p < 0.001). Statistically significant elevation of HOTAIR expression was found in stage III and stage II (p=0.001), compared to stage I. However, no difference was observed between stage II and stage III (p=0.533). There was no difference in both biomarkers in different histopathological types of thyroid cancer. ROC analysis was used for detection of thyroid cancer, midkine had AUC of 0.95 at a cutoff 897.5 pg/ml with a sensitivity of 98.0%, and specificity of 81.5% (p < 0.001). HOTAIR had AUC of 1 at a cutoff 11.8-fold change with a sensitivity and specificity of 100 %, (p < 0.001). We concluded that HOTAIR has high sensitivity and specificity in detection of thyroid cancer. It was correlated with tumor stage but not with histopathological types.

HOTAIR interacts with PRC2 complex regulating the regional preadipocyte transcriptome and human fat distribution.

Mechanisms governing regional human adipose tissue (AT) development remain undefined. Here, we show that the long non-coding RNA HOTAIR (HOX transcript antisense RNA) is exclusively expressed in gluteofemoral AT, where it is essential for adipocyte development. We find that HOTAIR interacts with polycomb repressive complex 2 (PRC2) and we identify core HOTAIR-PRC2 target genes involved in adipocyte lineage determination. Repression of target genes coincides with PRC2 promoter occupancy and H3K27 trimethylation. HOTAIR is also involved in modifying the gluteal adipocyte transcriptome through alternative splicing. Gluteal-specific expression of HOTAIR is maintained by defined regions of open chromatin across the HOTAIR promoter. HOTAIR expression levels can be modified by hormonal (estrogen, glucocorticoids) and genetic variation (rs1443512 is a HOTAIR eQTL associated with reduced gynoid fat mass). These data identify HOTAIR as a dynamic regulator of the gluteal adipocyte transcriptome and epigenome with functional importance for human regional AT development.

Exosomal lncRNA HOTAIR Promotes the Progression and Angiogenesis of Endometriosis via the miR-761/HDAC1 Axis and Activation of STAT3-Mediated Inflammation.

BackgroundLong non-coding RNA (lncRNA) and exosomes are implicated in endometriosis development. We measured the expression of an exosomal lncRNA, homeobox transcript antisense RNA (HOTAIR), and explored its molecular mechanism in endometriosis progression.MethodsExpression of HOTAIR and microRNA (miR)-761 in different endometrial tissues was measured. Exosomes were isolated from a culture medium of endometrial stromal cells (ESCs). RT-qPCR was used to measure HOTAIR expression in different exosome types. CCK-8, Edu, wound healing, transwell assays, flow cytometry and tube formation were used to detect the role of exosomal HOTAIR on ESCs and human umbilical vein endothelial cells (HUVECs). The relationship among miR-761, HOTAIR, and histone deacetylase 1 (HDAC1) was verified by dual-luciferase reporter assay. ESCs were transfected with miR-761 mimics or HDAC1 small interfering RNA (si-RNA) to ascertain if alterations in expression of miR-761 or HDAC1 could reverse the effect of exosomal HOTAIR. Then, we detected the effect of the HOTAIR/miR-761/HDAC1 axis on signal transducer and activator of transcription 3 (STAT3)-mediated inflammation. In vivo experiments were conducted to verify in vitro results.ResultsHOTAIR expression was upregulated and miR-761 expression was downregulated in ectopic endometrium tissues. HOTAIR was packaged into exosomes and transported from ESCs to surrounding cells. Exosomal HOTAIR promoted the proliferation, migration, and invasion, and inhibited the apoptosis of ESCs. Angiogenesis of HUVECs was enhanced after cultured with exosomal HOTAIR. HOTAIR acted as a competing endogenous RNA to downregulate miR-761 and increase HDAC1 expression. miR-761 overexpression or HDAC1 knockdown reversed the role of exosomal HOTAIR on ESCs and HUVECs. The HOTAIR/miR-761/HDAC1 axis could activate STAT3-related proinflammatory cytokines and stattic (inhibitor of phosphorylated-STAT3) could reverse the effect of HOTAIR on ESCs and HUVECs. In vivo experiments suggested that exosomal HOTAIR promoted the growth of endometrial lesions in vivo.ConclusionExosomal HOTAIR promoted the progression and angiogenesis of endometriosis by regulating the miR-761/HDAC1 axis and activating STAT3-mediated inflammation in vitro and in vivo, which may provide promising treatment for endometriosis.

Ghrelin Relieves Obesity-Induced Myocardial Injury by Regulating the Epigenetic Suppression of miR-196b Mediated by lncRNA HOTAIR

Introduction: Obesity has been believed to be closely linked with many kinds of diseases including atherosclerosis, hypertension, cerebrovascular thrombosis, and diabetes. Ghrelin and Homeobox transcript antisense RNA (HOTAIR) were believed to be involved in the regulation of myocardial injury. Methods: The obesity mice model was established through feeding mice (C57BL/6J, male, eight-week-old) with high-fat diet and palmitate (PA)-induced cardiomyocyte injury. RNA and protein levels were detected with Quantitative real-time PCR and Western blotting. The levels of TG, TCH, LDL, CK-MB, cTnl, and BNP in the serum or cell medium supernatant were measured using ELISA kits. The ROS level was detected with the DCFH-DA method. Binding sites between different targets were identified using detection of dual luciferase reporter assay. Cell apoptosis was analyzed by flow cytometry. RNA-binding protein immunoprecipitation and chromatin immunoprecipitation were used to detect the binding of DNMT3B with HOTAIR or miR-196b promoter. Results: The expression of HOTAIR was downregulated, and miR-196b was upregulated in the obese myocardial injury. Ghrelin attenuated PA-induced cardiomyocyte injury by increasing HOTAIR. HOTAIR regulated the expression of miR-196b by recruiting DNMT3B to induce methylation of the miR-196b gene promoter. The binding site between miR-196b and IGF-1 was identified. Discussion/Conclusion: We demonstrated that ghrelin attenuated PA-induced cardiomyocyte injury by regulating the HOTAIR/miR-196b/IGF-1 signaling pathway. Our findings might provide novel thought for the prevention and treatment of obesity-induced myocardial injury by targeting HOTAIR/miR-196b.

Long non-coding RNA HOTAIR/microRNA-761 sponge regulates PPME1 and further influences cell biological functions in thyroid carcinoma.

BackgroundMost well‐differentiated thyroid carcinomas display good therapeutic outcomes, but there are still some patients who are not sensitive to the general treatments lose their treatment opportunities. Thus, it is important to understand the molecular mechanisms that cause thyroid carcinoma, so as to find effective diagnostic and therapeutic targets.Aim of the studyTo explore the role of homeobox transcript antisense RNA (HOTAIR) in thyroid carcinoma through protein phosphatase methylesterase 1 (PPME1) by sponging microRNA 761 (miR‐761).MethodsThe regulation network amongst HOTAIR, miR‐761 and PPME1 was predicted by online sources. RT‐PCR was conducted to evaluate the expression of HOTAIR and miR‐761 in tumor tissues. Clinical data was collected and analyzed by Chi‐square test. Cell apoptosis and proliferation was evaluated using three types of cancer cells (HTh‐7, CAL‐62, BCPAP) after treated with si‐HOTAIR and miR‐761inhibitor. The binding site among HOTAIR, miR‐761 and PPME1 was verified by dual luciferase reporter assay. PPME1 expression was measured after HOTAIR and miR‐761 were suppressed by western blot. Survival time was measured in nude mice using log‐rank test.ResultsHOTAIR was expressed to a significantly greater extent than miR‐761 in thyroid tumor tissues (P < .001). miR‐761 and PPME1 were negatively correlated (coef = −1.91, P < .001). HOTAIR competitively binds to miR‐761 and miR‐761 directly targets PPME1. HOTAIR was highly correlated with TNM (χ 2 = 5.797, P = .016), tumor size (χ 2 = 7.955, P = .005) and lymphatic metastasis (χ 2 = 6.0, P = .014). HOTAIR promoted cell proliferation and inhibited cell apoptosis, whereas miR‐761 did not. HOTAIR elevated and miR‐761 suppressed PPME1 expression. HOTAIR expression appears to affect the survival time in vivo.ConclusionHOTAIR regulated thyroid cancer cells by binding to miR‐761 through PPME1.

RETRACTED: HOTAIR Accelerates Dyskinesia in a MPTP-Lesioned Mouse Model of PD via SSTR1 Methylation-Mediated ERK1/2 Axis

Homeobox transcript antisense RNA (HOTAIR), has been associated with neuroprotective effects in Parkinson’s disease (PD). However, the underlying mechanisms still remain unclear. Hence, this present study attempted to clarify the functional relevance of HOTAIR in PD. We established an in vivo mouse model of PD using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and an in vitro cell model of PD by treating dopaminergic neuron MN9D cells with 1-methyl-4-phenylpyridinium species (MPP+). The expressions of somatostatin receptor 1 (SSTR1) and HOTAIR were altered to examine their effects on MN9D cell viability and apoptosis, as well as on movement impairments in MPTP-induced PD mouse model. The results indicated that HOTAIR expression was upregulated and SSTR1 was downregulated in in vivo and in vitro PD models. HOTAIR could bind to the promoter region of SSTR1, resulting in an increase of SSTR1 methylation through the recruitment of DNA methyltransferases in PD cell models. Notably, overexpression of HOTAIR and silencing of SSTR1 enhanced dopaminergic neuron apoptosis in MN9D cells and exacerbated dyskinesia in MPTP-induced PD mouse model. Collectively, overexpressed HOTAIR stimulates DNA methylation of SSTR1 to reduce SSTR1 expression, thereby accelerating dyskinesia and facilitating dopaminergic neuron apoptosis in a MPTP-lesioned PD mouse model via activation of the ERK1/2 axis.

LncRNA HOTAIR knockdown inhibits glycolysis by regulating miR-130a-3p/HIF1A in hepatocellular carcinoma under hypoxia

High rate of glycolysis supports hepatocellular carcinoma (HCC) cell growth even in a hypoxic environment. However, the mechanism underlying glycolysis under hypoxia remains largely unknown. Long noncoding RNAs (lncRNAs) play essential roles in regulating glucose metabolism in cancers. This study aimed to explore the role of lncRNA homeobox transcript antisense RNA (HOTAIR) in HCC glycolysis under hypoxia. Thirty-eight HCC patients were recruited. HepG2 and Huh7 cells were used for study in vitro. The expression levels of HOTAIR, microRNA-130a-3p (miR-130a-3p) and hypoxia inducible factor 1 alpha (HIF1A) were measured by quantitative real-time polymerase chain reaction and western blot, respectively. The glycolysis under hypoxia (1 % O2) condition was investigated by glucose consumption, lactate production and hexokinase 2 (HK2) level. The target interaction between miR-130a-3p and HOTIR or HIF1A was analyzed by bioinformatics analysis, luciferase assay, RNA pull-down and RNA immunoprecipitation. We found that HOTAIR expression was enhanced in HCC tissues and cells. Under hypoxia condition, HOTAIR expression was increased and its knockdown inhibited glycolysis in HCC cells. HOTAIR was validated as a decoy of miR-130a-3p and miR-130a-3p deficiency reversed the suppressive effect of HOTAIR silence on glycolysis under hypoxia. HIF1A was indicated as a target of miR-130a-3p and miR-130a-3p overexpression repressed glycolysis under hypoxia by targeting HIF1A. Moreover, HIF1A expression was regulated by HOTAIR and miR-130a-3p. In conclusion, knockdown of HOTAIR suppressed glycolysis by regulating miR-130a-3p and HIF1A in HCC cells treated by hypoxia, elucidating a novel mechanism in HCC glycolysis.

Bioinformatics analysis of the expression of HOXC13 and its role in the prognosis of breast cancer.

The homeobox (HOX) genes, a class of transcription factors, are known to promote embryonic development and induce tumor formation. To date, the HOXA and HOXB gene families have been reported to be associated with breast cancer. However, the expression and exact role of homeobox C13 (HOXC13) in breast cancer has not yet been investigated. In the present study, the HOXC13 expression in human breast cancer was evaluated using the Oncomine database and Cancer Cell Line Encyclopedia (CCLE). Next, the Gene expression-based Outcome for Breast cancer online database, cBioportal, University of California Santa Cruz Xena browser and bc-GenExMinerv were used to explore the specific expression of HOXC13 in breast cancer. The methylation and mutation status of HOXC13 in breast cancer was then validated using the CCLE and cBioportal databases. Finally, the co-expression of HOX transcript antisense RNA (HOTAIR) and HOXC13 in breast cancer were analyzed and their impact on clinical prognosis determined. It was found that the expression of HOXC13 was high in breast cancer compared with other types of cancer, such as gastric cancer and colon cancer. Following co-expression analysis, a significant positive association was identified between HOTAIR and HOXC13. An association between HOTAIR and HOXC13, and lymph node and distant metastasis recurrence was also revealed during the development of breast cancer. Of note, survival analysis showed that high expression of HOTAIR and HOXC13 predicted poor prognosis. These findings revealed that HOXC13 plays an important role in the progression of breast cancer. However, the specific mechanism needs to be confirmed by subsequent experiments.

LncRNA HOTAIR improves diabetic cardiomyopathy by increasing viability of cardiomyocytes through activation of the PI3K/Akt pathway.

The current study aimed to investigate the role of long non-coding RNA (lncRNA) homeobox transcript antisense RNA (HOTAIR) in the pathogenesis of diabetic cardiomyopathy. Patients with diabetic cardiomyopathy, patients with diabetes but without cardiomyopathy and healthy controls were included in the current study. All participants underwent myocardial biopsy to collect myocardial tissues. Blood samples were also collected from each participant to prepare serum. Expression of HOTAIR in myocardial tissues was detected by reverse transcription-quantitative polymerase chain reaction. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic value of serum HOTAIR for diabetic cardiomyopathy. AC16 human cardiomyocyte cells were treated with high glucose to observe the changes in expression of HOTAIR and phosphorylation of Akt. HOTAIR expression vector was transfected into cells of AC16 cell line and the effects of HOTAIR overexpression on cell viability and Akt phosphorylation were detected by MTT assay and western blot analysis, respectively. HOTAIR expression was significantly downregulated in myocardial tissues and serum of patients with diabetic cardiomyopathy compared with patients with diabetes and healthy controls. Serum HOTAIR could be used to effectively distinguish patients with diabetic cardiomyopathy from healthy controls. High glucose treatment inhibited HOTAIR expression and Akt phosphorylation. HOTAIR overexpression promoted Akt phosphorylation. HOTAIR overexpression improved AC16 cell viability, while PI3K/Akt inhibitor treatment reduced this effect. LncRNA HOTAIR may improve diabetic cardiomyopathy by increasing the viability of cardiomyocytes through activation of the PI3K/Akt pathway.

Long Noncoding RNA HOTAIR: An Oncogene in Human Cervical Cancer Interacting With MicroRNA-17-5p.

Increasing evidence has indicated that long noncoding RNAs (lncRNAs) are a class of significant regulators in various tumorigenesis processes. The lncRNA homeobox transcript antisense RNA (HOTAIR) has been reported to act as a functional lncRNA in cervical cancer development. The present study investigated the underlying mechanism of HOTAIR and miR-17-5p in cervical cancer tumorigenesis. The results showed that HOTAIR expression was significantly upregulated in both cervical cancer tissues and cell lines. Loss-of-function experiments showed that HOTAIR knockdown inhibited the proliferation, migration, and invasion of cervical cells. In addition, miR-17-5p expression was downregulated in cervical cancer tissues and cell lines. Pearson’s correlation analysis indicated that miR-17-5p expression was negatively correlated to that of HOTAIR. Luciferase reporter assay revealed that miR-17-5p directly targeted HOTAIR 3′-UTR. Rescue experiments showed that miR-17-5p knockdown could reverse the tumor-suppressing effect caused by si-HOTAIR transfection. In summary, our results reveal the tumor-promoting role of HOTAIR in cervical cancer via sponging miR-17-5p, providing a novel therapeutic target for future treatment of cervical cancer.

Long non-coding RNA HOTAIR and STAT3 synergistically regulate the cervical cancer cell migration and invasion

Homeobox (HOX) transcript antisense RNA (HOTAIR) is a long intergenic non-coding RNA (lncRNA) that has been reported to be highly upregulated in several types of cancers. However, the role of HOTAIR in human cervical cancer is still unclear. We therefore investigated the expression and probable function of HOTAIR in cervical cancer cells. The expression of HOTAIR was examined in (HeLa, CaSki, ME-180, HT-3) and Human Cervical Epithelial Cells (HCerEpiC) by qRT-PCR. Transfection of si-NC, si-HOTAIR or si-STAT3 was carried out with the help of Lipofectamine 2000. The cell viability was assessed by CCK-8 assay. The cell migration and invasion was examined by wound healing and Boyden chamber assays. Protein expression was determined by western blotting. Our results showed that expression of HOTAIR was significantly upregulated in cervical cancer cells and inhibition of the expression of HOTAIR in HeLa cervical cancer cells resulted in suppression of cell proliferation, migration and invasion. Further, analysis of the promoter of HOTAIR, revealed that STAT3 could potentially regulate the activity of the HOTAIR in cervical cancer cells and inhibition of STAT3 had similar effects on the proliferation, migration and invasion of the cervical cancer cells as that of HOTAIR. Further, the suppression of STAT3 expression was associated with concomitant downregulation of IncRNA HOTAIR as indicated by the qRT-PCR. To unveil if STAT3 and HOTAIR have synergistic effects on the cell migration and invasion, si-STAT3 and si-HOTAIR were co-transformed into cervical HeLa cancer cells and it was observed that STAT3 and HOTAIR could synergistically inhibit the proliferation, migration and invasion of the cervical cancer cells. Taken together we conclude that HOTAIR and STAT3 synergistically regulate the proliferation, migration and invasion of cervical cancer cells.

The prognostic impact of long noncoding RNA HOTAIR in leukemia and lymphoma: a meta-analysis

ABSTRACT Objectives: Multiple studies have shown that the expression level of Homeobox (HOX) transcript antisense RNA (HOTAIR) has a correlation with the diagnosis and prognosis of acute leukemia (AL) and lymphoma. The prognostic significance of HOTAIR on AL and lymphoma has been controversial. Our study thus was performed to further reveal its prognostic value in leukemia and lymphoma. Methods: By literature searching in some common electronic databases, five studies covering a number of 531 patients were included in this meta-analysis. We extracted useful data to calculate the pooled hazard ratio (HR) and p-value. Results: The combined HR estimated for overall survival (OS) was 1.87 (95% confidence interval (CI): 1.03–3.47; p = .041) when comparing patients with high HOTAIR with those low. For event/disease/relapse-free survival, the HR was 1.53 (95%CI: 0.58–4.06; p = .39). Subgroup analyses showed that the HR for OS was 2.32 (95%CI: 1.56–3.44; p = .000) in patients with AL and 1.24 (95%CI: 0.21–7.45; p = .817) in lymphoma. Additionally, the Ann-Arbor stage (p = .0009) and the international prognostic index score (p = .0065) were found to be statistically significant between patients with high and low HOTAIR expression. Also, the hemoglobin (HGB) level (p = .008), platelet (PLT) count (p = .001) and blasts in bone marrow (p = .001), but not the French–American–British classification, were found statistically significant. Discussion: Although our analysis has its limitation, it showed that high expression of HOTAIR had a significantly inferior impact on OS and some clinical parameter of leukemia and lymphoma patients. Conclusion: HOTAIR played an important prognostic role in leukemia and lymphoma and might serve as a potential target for therapeutic intervention in those patients.

Clinicopathological and prognostic significance of homeobox transcript antisense RNA expression in various cancers: A meta-analysis.

Background:Increased expression of the homeobox (HOX) transcript antisense RNA (HOTAIR) has been reported in multiple types of malignancies and enhances the proliferation and migration of cancer cells. However, the association between HOTAIR expression and tumor progression and prognosis remains controversial. We performed a meta-analysis to clarify the association between the expression of HOTAIR and the clinicopathological features and prognosis in different cancers.Methods:A systematic search of the PubMed, Web of Science, EMBASE, and Ovid databases was conducted, up to September 2016, for eligible studies involving HOTAIR expression and malignancies. The odds ratios (ORs), hazard ratios (HRs), and corresponding 95% confidence intervals (CIs) were calculated using fixed- or random-effect models. Any publication bias was evaluated using Begg and Egger tests, and adjusted using the trim and fill method if a bias existed.Results:A total of 4116 patients from 44 studies were included in our meta-analysis. The results showed that high HOTAIR expression was associated with an advanced clinical tumor stage (OR = 3.90, 95% CI = 3.02–5.03, P < .001), lymph node metastasis (OR = 3.11, 95% CI = 2.15–4.49, P < .001), poor differentiation of the tumor (OR = 1.56, 95% CI = 1.01–2.41, P = .03), and worse prognosis (HR = 2.16, 95% CI = 1.73–2.69, P < .001) in different cancer types. HOTAIR expression was more predictive in monitoring the clinical tumor stage of patients and there was no significant heterogeneity or publication bias found in the analysis.Conclusion:Our meta-analysis suggests that HOTAIR is positively correlated with tumor development and negatively correlated with clinical outcome. Thus, an increase in HOTAIR expression may be a potential biomarker for tumor progression and evaluation of prognosis.

Long non-coding RNA HOTAIR enhances radioresistance in MDA-MB231 breast cancer cells.

The aim of the present study was to investigate the radiosensitizing effects of homeobox (HOX) transcript antisense RNA (HOTAIR) long non-coding RNA on breast cancer tumor cells and examine the underlying mechanisms. Recombinant plasmid vectors containing HOTAIR gene were constructed and MDA-MB231 cells were transfected with these plasmids using liposomes. The cells were treated with radiation and cell apoptosis, proliferation, and double-stranded DNA breaks were examined. HOXD10, phosphorylated AKT (p-AKT) and p-BAD expression levels were measured using western blot analysis. The results showed a higher expression of HOTAIR in advanced tumor cells. HOTAIR efficiently enhanced radioresistance in MDA-MB231 breast cancer cells and accelerated proliferation through the Akt pathway by targeting HOXD10. In conclusion, the findings demonstrated that HOTAIR gene is a valid therapeutic target for the reversal of radiotherapy resistance in breast cancer.

HOTAIR Epigenetically Modulates PTEN Expression via MicroRNA-29b: A Novel Mechanism in Regulation of Liver Fibrosis

Homeobox transcript antisense RNA (HOTAIR), as a long intergenic non-coding RNA (lincRNA), is upregulated in various cancers and involved in diverse cellular functions. However, its role in liver fibrosis is unclear. In this study, HOTAIR expression was upregulated in hepatic stellate cells (HSCs) invivo and invitro during liver fibrosis. HOTAIR knockdown suppressed HSC activation including α-smooth muscle actin (α-SMA) and typeIcollagen invitro and invivo. Both HSC proliferation and cell cycle were inhibited by HOTAIR knockdown. Notably, inhibition of HOTAIR led to an increase in PTEN, associated with the loss of DNA methylation. miR-29b-mediated control of PTEN methylation was involved in the effects of HOTAIR knockdown. HOTAIR was confirmed a target of miR-29b and lack of the miR-29b binding site in HOTAIR prevented the suppression of miR-29b, suggesting HOTAIR contributes to PTEN expression downregulation via sponging miR-29b. Interestingly, increased HOTAIR was also observed in hepatocytes during liver fibrosis. Loss of HOTAIR additionally led to the increase in PTEN and the reduction in typeIcollagen in hepatocytes. Collectively, we demonstrate that HOTAIR downregulates miR-29b expression and attenuates its control on epigenetic regulation, leading to enhanced PTEN methylation, which contributes to the progression of liver fibrosis.

Suppression of PDCD4 mediated by the long non-coding RNA HOTAIR inhibits the proliferation and invasion of glioma cells.

Programmed cell death protein 4 (PDCD4) has recently been demonstrated to be implicated in translation and transcription, and the regulation of cell growth. However, the mechanisms underlying PDCD4 function in glioma cells remain to be elucidated. The current study investigated the function and regulation of PDCD4 and the results demonstrated that the expression of PDCD4 was significantly reduced in glioma cells compared with normal cells. When PDCD4 was overexpressed in glioma cells, the proliferation rate and invasive capability of the cells greatly decreased, suggesting that PDCD4 functions as a tumor suppressor in this cell type. In addition, the histone modification status of the PDCD4 gene was analyzed, and chromatin immunoprecipitation assay identified a high density of histone 3 lysine 27 trimethylation on the promoter of PDCD4, which was associated with the long non-coding RNA, homeobox transcript antisense RNA (HOTAIR). The expression of HOTAIR was significantly increased in glioma cells compared with normal cells, and it exerted its function in a polycomb repressive complex 2-dependent manner. These results may provide novel approaches to therapeutically target PDCD4 and HOTAIR in patients with gliomas.

Long Non-coding RNA HOTAIR Promotes Parkinson's Disease Induced by MPTP Through up-regulating the Expression of LRRK2.

Homeobox (HOX) transcript antisense RNA (HOTAIR), as a long intergenic noncoding RNA (lincRNA), is known to be overexpressed in several cancers. However, the role of HOTAIR in Parkinson's disease (PD) remains unclear. A mouse model of PD was developed by intraperitoneal injection of MPTP (N-methyl-4-phenyl-1,2,3,6- tetrahydropyridine). The expression of HOTAIR and LRRK2 (leucine-rich repeat kinase 2) were detected in the PD mice and in Human neuroblastoma cell lines SH-SY5Y pretreated with MPP+ (N-methyl-4-phenylpyridinium). The effect of HOTAIR on the expression of LRRK2 was examined in SH-SY5Y cells through overexpressing HOTAIR. A MTT (3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide) assay was performed to measure the cell viability of SH-SY5Y cells. si-HOTAIR (siRNA-HOTAIR) was utilized to investigate the effect of HOTAIR on the expression of LRRK2 in vivo. In this study, upregulation of HOTAIR and LRRK2 were found in the midbrain of PD mice induced by MPTP and in SH-SY5Y cells pretreated with 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+, which was abrogated by overexpression of LRRK2. In mouse model of PD treated with si-HOTAIR, the expression of LRRK2 was decreased. In conclusion, high expression of HOTAIR promoted the onset of PD induced by MPTP. Moreover, the finding that HOTAIR promoted PD induced by MPTP through regulating LRRK2 expression could add our understanding of the molecular mechanisms in PD.

A Feed-Forward Regulatory Loop between HuR and the Long Noncoding RNA HOTAIR Promotes Head and Neck Squamous Cell Carcinoma Progression and Metastasis

Background/Aims: The lncRNA Homeobox (HOX) transcript antisense RNA (HOTAIR) is overexpressed in numerous cancers. HuR is also overexpressed during tumourigenesis and is abnormally present within the cytoplasm, where it binds to AU-rich elements in the 3′UTRs of target mRNA and post-transcriptionally regulates the expression of its target genes. However, whether HOTAIR is regulated and the mechanisms by which it affects head and neck squamous cell carcinoma (HNSCC) are not well understood. Methods: MTT, cell cycle arrest and apoptotic assays were used to examine the effects of HOTAIR and HuR on cell viability in SCC25 and FaDu cells. Wound healing and transwell invasion analysis were performed to detect the effects of HOTAIR and HuR on cell migration and invasion. The interaction between HuR and HOTAIR was confirmed via qRT-PCR, western blots, luciferase reporter and RIP assays. Finally, qRT-PCR analysis was used to detect the levels of HuR and HOTAIR in HNSCC tumours and adjacent normal tissues. Results: Knockdown of HOTAIR and HuR decreased cell viability, cellular migration and invasion. Moreover, HuR interacted and stabilized HOTAIR stability and thus promoted HOTAIR expression. Notably, HOTAIR acted as a miRNA sponge for HuR. HuR also reinforced HOTAIR sponge activity through miRNA recruitment, thus enhancing HuR expression in turn. Finally, HuR and HOTAIR levels were positively correlated and significantly up-regulated in tumours samples. Conclusion: We demonstrated the existence of a regulatory loop in which the expression of HOTAIR and HuR is reciprocally and temporally regulated during the metastasis and progression of HNSCC.

Long Intergenic Noncoding RNA HOTAIR Is Overexpressed and Regulates PTEN Methylation in Laryngeal Squamous Cell Carcinoma

Homeobox (HOX) transcript antisense RNA (HOTAIR) is a long intergenic noncoding RNA (lincRNA) that is significantly overexpressed in breast and hepatocellular cancers. It remains unclear, however, whether HOTAIR plays an oncogenic role in human laryngeal squamous cell cancer (LSCC). We therefore investigated the expression and functional role of HOTAIR in LSCC. HOTAIR levels were significantly higher in LSCC than in corresponding adjacent non-neoplastic tissues, and patients with poor histological grade or advanced clinical stage had higher HOTAIR expression. Log-rank test showed a significant association between high levels of HOTAIR and poor prognosis in LSCC patients. Multivariate Cox analysis suggested that HOTAIR is an independent prognostic factor of LSCC. siRNA-mediated knockdown of HOTAIR led to reduced invasion and increased apoptosis of Hep-2 cells invitro and significantly reduced growth of LSCC xenograft tumors in mice. Moreover, PTEN methylation was significantly reduced in Hep-2 cells depleted of HOTAIR. Taken together, these results suggest that the oncogenic role of HOTAIR in LSCC is related to promotion of PTEN methylation. HOTAIR could serve as a marker for LSCC prognosis and a potential target for therapeutic intervention.