HOX Transcript Antisense Intergenic RNA Expression Research Articles

Knockdown of HOTAIR Alleviates High Glucose-Induced Apoptosis and Inflammation in Retinal Pigment Epithelial Cells.

Diabetic retinopathy (DR) is one of the most common microvascular complications in diabetes. Accumulating evidence demonstrated that long non-coding RNAs (lncRNAs) played critical regulatory roles in DR. However, the role of lncRNA HOX Transcript Antisense Intergenic RNA (HOTAIR) in the high glucose (HG)-induced human retinal pigment epithelial (RPE) cell injury remains unclear. Herein, we found the expression of HOTAIR was increased in the retina of DR rats and HG-induced ARPE-19 cells. Knockdown of HOTAIR improved viability, inhibited apoptosis, increased Bcl-2 protein levels, and decreased Bax and cleaved caspase 3 protein levels in HG-treated ARPE-19 cells. Moreover, enzyme-linked immunosorbent assay showed that HOTAIR silencing reduced interleukin 6 and tumor necrosis factor-α release of ARPE-19 cells under HG conditions. Mechanistically, luciferase reporter assay and RNA immunoprecipitation assay validated that HOTAIR could directly sponge miR-326 to upregulate transcription factor 4 (TCF4) expression. Furthermore, rescue experiments confirmed that HOTAIR promoted apoptosis and inflammation of HG-treated ARPE-19 cells by the miR-326/TCF4 axis. In summary, HOTAIR enhanced HG-induced retinal pigment epithelial cell injury by promoting apoptosis and inflammation, shedding light on the importance of HOTAIR as a novel potential target for DR treatment.

LncRNA HOTAIR promotes DNA damage repair and radioresistance by targeting ATR in colorectal cancer.

Long non-coding RNAs (lncRNAs) have been implicated in cancer progression and drug resistance development. Moreover, there is evidence that lncRNA HOX transcript antisense intergenic RNA (HOTAIR) is involved in colorectal cancer (CRC) progression. The present study aimed to examine the functional role of lncRNA HOTAIR in conferring radiotherapy resistance in CRC cells, as well as the underlying mechanism. The relative expression levels of HOTAIR were examined in 70 pairs of CRC tumor and para-cancerous tissues, as well as in radiosensitive and radioresistant samples. The correlations between HOTAIR expression levels and clinical features of patients with CRC were assessed using the Chi-square test. Functional assays such as cell proliferation, colony formation and apoptosis assays were conducted to determine the radiosensitivity in CRC cells with HOTAIR silencing after treatment with different doses of radiation. RNA pull-down assay and fluorescence in situ hybridization (FISH) were used to determine the interaction between HOTAIR and DNA damage response mediator ataxia-telangiectasia mutated- and Rad3-related (ATR). HOTAIR was significantly upregulated in CRC tumor tissues, especially in radioresistant tumor samples. The elevated expression of HOTAIR was correlated with more advanced histological grades, distance metastasis and the poor prognosis in patients with CRC. Silencing HOTAIR suppressed the proliferation and promoted apoptosis and radiosensitivity in CRC cells. HOTAIR knockdown also inhibited the tumorigenesis of CRC cells and enhanced the sensitivity to radiotherapy in a mouse xenograft model. Moreover, the data showed that HOTAIR could interact with ATR to regulate the DNA damage repair signaling pathway. Silencing HOTAIR impaired the ATR-ATR interacting protein (ATRIP) complex and signaling in cell cycle progression. Collectively, the present results indicate that lncRNA HOTAIR facilitates the DNA damage response pathway and promotes radioresistance in CRC cells by targeting ATR.

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.

Clinicopathological and prognostic significance of the long non-coding RNA HOTAIR high expression in head and neck squamous cell carcinoma: a systematic review and meta-analysis.

BackgroundLong non-coding RNAs (lncRNAs) have been demonstrated to possess critical biological functions that regulate occurrence and progression of tumors. The HOX transcript antisense intergenic RNA (HOTAIR) is one of the most studied lncRNAs. This study was designed to investigate the association of HOTAIR expressions with clinicopathologic features and prognosis in head and neck squamous cell carcinoma (HNSCC).MethodsThe PubMed, Web of Science, Embase, Cochrane Library and SCOPUS databases were searched. The studies published before September 10, 2021 were screened. Two authors independently screened the literature and extracted data based on inclusion and exclusion criteria. Meta-analysis, bias assessment, sensitivity analysis and subgroup analysis were performed to improve accuracy and reliability.ResultsSeven studies comprising 546 patients were analysed to clarify the relationship between clinicopathologic features and HOTAIR expression, and six studies with 856 patients were applied to evaluate the effects of HOTAIR expressions on the prognosis. After removing those outliers through Galbraith plots and/or sensitivity analysis, the pooled results showed high HOTAIR expressions were associated with high T stage [odds ratio (OR) =2.32, 95% confidence interval (CI): 1.38–3.89, P=0.001], lymphnode metastasis (OR =2.71, 95% CI: 1.57–4.67, P=0.0003), high TNM stage (OR =3.92, 95% CI: 2.28–6.72, P<0.00001), poor histological grade (OR =2.21, 95% CI: 1.02–4.83, P=0.046), poor overall survival (OS) [hazard ratio (HR) =1.74, 95% CI: 1.19–2.56, P=0.005] and poor disease-free survival (DFS) (HR =1.64, 95% CI: 1.09–2.47, P=0.02). Subgroup analyses of T stage, lymphnode metastasis and histological grade identified possible heterogeneity sources, respectively ethnicity, cut-off, and detection methods.ConclusionsThese findings suggest HOTAIR might serve as an excellent prognostic biomarker and predictor of clinicopathologic features in HNSCC.

LncRNA HOTAIR promotes the proliferation and invasion/metastasis of breast cancer cells by targeting the miR-130a-3p/Suv39H1 axis

Long noncoding RNAs (lncRNAs) are a group of transcripts, more than 200 bp in size and regulate cell proliferation, differentiation and apoptosis. LncRNA HOX Transcript Antisense Intergenic RNA (HOTAIR) promotes tumor progression and increases cancer susceptibility by regulating microRNA expression and function. HOTAIR regulates miR-130a-3p expression in hepatocellular carcinoma cells. Bioinformatics analysis revealed that Suv39H1 contained a putative binding site for miR-130a-3p. We speculate that LncRNA HOTAIR promotes the proliferation and invasion/metastasis of breast cancer (BC) cells by targeting the miR-130a-3p/Suv39H1 axis. High HOTAIR expression facilitated BC cell growth and metastasis. HOTAIR functioned as a ceRNA by sponging miR-130a-3p and subsequently promoted Suv39H1-mediated AKT/mTOR signaling. Suv39H1 restoration abolished the effects of HOTAIR knockdown on BC cell growth and metastasis. HOTAIR facilitated the Suv39H1-mediated AKT/mTOR pathway by acting as a molecular sponge of miR-130a-3p.Our results provide a better understanding of the interactions of HOTAIR and miR-103a-3p/Suv39H1 in BC and a potential prognostic biomarker and therapeutic target for BC.

Long noncoding RNA HOTAIR polymorphisms and susceptibility to bipolar disorder: a preliminary case–control study

Recent studies have shown that long noncoding RNAs contribute to the pathogenesis of bipolar disorder (BD). In this study, we genotyped four HOX Transcript Antisense Intergenic RNA (HOTAIR) gene polymorphisms to investigate if these variations could affect the risk of BD and its clinical subtypes. A total of 357 subjects, comprised of 194 BD patients and 163 age-matched healthy controls, were enrolled. Genotyping was carried out using PCR-RFLP and ARMS-PCR methods. We detected significant associations between the HOTAIR gene rs1899663 G/T, rs12826786 C/T, rs4759314 A/G, and rs920778 C/T polymorphism and the risk of BD under allelic, recessive, dominant, and codominant contrasted genetic models. The CT genotype of rs920778 C/T, GT genotype of rs1899663 G/T, and CT genotype of rs12826786 C/T polymorphisms enhanced the risk of BD type II (BDII). In contrast, the GG genotype of rs4759314 A/G polymorphism significantly diminished BDII risk by 83%. A positive association was noticed between CTTA and CTCG haplotypes of rs920778/rs1899663/rs12826786/rs4759314 and BD risk. Our findings reveal an interactive effect of HOTAIR polymorphisms on the development of BD and its subtypes. Further functional studies are needed to elucidate the role of these variations on HOTAIR expression and epigenetic status.

LncRNA HOTAIR sponges miR-301a-3p to promote glioblastoma proliferation and invasion through upregulating FOSL1

Glioblastoma, one of the most fatal brain tumors, is associated with a dismal prognosis and an extremely short overall survival. We previously reported that the overexpressed transient receptor potential channel TRPM7 is an essential glioblastoma regulator. Accumulating evidence suggests that long noncoding RNAs (lncRNAs) play an important role in glioma's initiation and progression. However, the function of lncRNA, HOX transcript antisense intergenic RNA (HOTAIR) mediated by TRPM7 in glioma remains unclear. In this study, HOTAIR expression was found to be positively regulated by TRPM7, significantly upregulated in glioma tissues, and is a poor prognosis factor for glioma patients. Moreover, reduced HOTAIR expression impeded the proliferation and invasion of glioma cells. Mechanistically, HOTAIR directly interacted with miR-301a-3p, and downregulation of miR-301a-3p efficiently reversed FOSL1 suppression induced by siRNA HOTAIR, which implied that HOTAIR positively regulated FOSL1 level through sponging miR-301a-3p and played an oncogenic role in glioma progression. In contrast to HOTAIR's role, miR-301a-3p alone served as a tumor suppressor to decrease glioma cell viability and migration/invasion. In agreement with HOTAIR's role, FOSL1 functioned as a tumorigenic gene in glioma pathogenesis, which was highly expressed in glioma tissues, and was shown to be an unfavorable prognostic factor for glioma patients. Mechanically, FOSL1 inhibition by siRNA FOSL1 efficiently rescued the oncogenic-like phenotypes caused by the miR-301a-3p inhibitor in glioma pathogenesis. SignificanceOur study elucidated the role of TRPM7-mediated HOTAIR as a miRNA sponge to target downstream FOSL1 oncogene and therefore consequently contribute to gliomagenesis, which shed new light on TRPM7/lncRNA-directed diagnostic and therapeutic approach in glioma.

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.

The combined use of long non-coding RNA HOTAIR and polycomb group protein EZH2 as a prognostic marker of lung adenocarcinoma

BackgroundThe long non-coding RNA Hox transcript antisense intergenic RNA (HOTAIR) and polycomb group protein Enhancer of zeste homolog 2 (EZH2) function cooperatively in carcinogenesis. However, their combined usage as prognostic markers for lung adenocarcinoma remains unverified. Materials and MethodsTo validate their combined usage, we measured the expression of both genes in the surgical samples from 83 adenocarcinoma cases using quantitative real-time PCR and analyzed the association between the gene expressions and various clinicopathological factors. We also examined the EZH2 protein levels using immunohistochemistry. Finally, we analyzed the association between their expression status and the overall survival using 54 stage I cases. ResultsBoth genes were expressed at significantly higher levels in adenocarcinoma tissues than normal lung. EZH2 expression, but not HOTAIR expression, was significantly higher in solid adenocarcinoma than in other subtypes. In the survival analysis using stage-I cases, both HOTAIR expression and EZH2 protein levels were associated with a worse prognosis. The overall survival was highest in the low-HOTAIR and low-EZH2 group (low-low), followed by the high-low or low-high group and the high-high group. According to the multivariate analysis, the high-high status of HOTAIR-EZH2 (protein) was significantly associated with a worse prognosis than the low-low group. ConclusionMore accurate prognoses would be possible by simultaneously measuring both genes than measuring either. The high-HOTAIR and high-EZH2 (protein) status, compared to the low-low, is proposed as an independent prognostic marker for stage I cases. Thus, it would serve as a potential biomarker for anti-EZH2 therapy.

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.

Long noncoding RNA HOTAIR functions as ceRNA to regulate MMP2 in paraquat induced lung epithelial-mesenchymal transition

Paraquat (PQ) poisoning induces epithelial-mesenchymal transition (EMT) in the lungs, resulting in pulmonary fibrosis with a poor prognosis. Although competitive endogenous RNA (ceRNA) networks are known to exert post-transcriptional regulatory effects, the roles of such networks in PQ-induced EMT remain unknown. We explored the potential ceRNA network involved in PQ-induced pulmonary EMT. The male BALB/c mice were injected with 10 mg/kg PQ intraperitoneally and the lungs were harvested at 21st day. The A549 cells were treated with 60 μmol/L PQ for 6 days. We determined the expression level of epithelia cadherin (E-cadherin) and α-smooth muscle actin (α-SMA) in the lungs and A549 cells after PQ exposure. We also detected the expression level of the long noncoding RNA (lncRNA) HOX transcript antisense intergenic RNA (HOTAIR), microRNA-17-5p (miR-17-5p), and matrix metalloproteinase 2 (MMP2). We used specific siRNA to determine the influence of HOTAIR on MMP2. We also transfected a mimic or inhibitor of miR-17-5p to explore its role. Moreover, we used the luciferase reporter gene assay to confirm the relationship between miR-17-5p and HOTAIR or MMP2. In this study, we found that MMP2 and HOTAIR were upregulated and miR-17-5p was downregulated in PQ-induced EMT. The knockdown of HOTAIR decreased the expression of MMP2, and the upregulation of miR-17-5p suppressed HOTAIR and MMP2. Apparently, the downregulation of miR-17-5p increased the expression of HOTAIR and MMP2. The expression of α-SMA was negatively regulated by miR-17-5p after PQ exposure. In addition, the luciferase reporter gene assay confirmed that HOTAIR and MMP2 had direct binding sites with miR-17-5p. In conclusion, this study showed that the HOTAIR could act as a ceRNA for miR-17-5p to regulate MMP2 expression in PQ-induced pulmonary EMT.

LncRNA expression and SDHB mutations in pheochromocytomas and paragangliomas

Although pheochromocytomas and paragangliomas (PPGLs) are usual low-grade neoplasms, the metastatic forms of these lesions are associated with high morbidity and mortality. Recent studies have discovered multiple aberrantly expressed long non-coding RNAs (lncRNAs) in cancers that may have regulatory roles in tumor pathogenesis and metastasis; however, the roles of some lncRNAs in PPGLs are still unknown. The expression levels of lncRNAs including metastasis-associated lung adenocarcinoma transcript (MALAT1), prostate cancer antigen 3 (PCA3), and HOX transcript antisense intergenic RNA (HOTAIR) in PPGLs were analyzed by in situ hybridization, using two tissue microarrays (TMAs). The pheochromocytoma (PCC) TMA consisted of normal adrenal medulla (N = 25), non-metastatic PCCs (N = 76) and metastatic PCCs (N = 5) while the paraganglioma (PGL) TMA had 73 non-metastatic PGLs and 5 metastatic PGLs. Immunohistochemical staining was performed on all samples with an anti-SDHB antibody. The correlations between lncRNA expression, loss of SDHB expression and clinical characteristics including tumor progression and disease prognosis were investigated. The expression levels of MALAT1 and PCA3 were significantly elevated (2.5–3.9 folds) in both non-metastatic and metastatic PCCs compared to normal adrenal medulla, although there were no significant differences between the non-metastatic and metastatic neoplasms. In contrast to non-metastatic PGLs, metastatic PGLs had significantly upregulated expression of MALAT1, PCA3, and HOTAIR. SDHB loss was more frequently observed in PGLs (25 of 78), especially in metastatic PGLs (5 of 5), compared to PCCs (2 of 81) and in 0 of 5 metastatic PCCs. Patients with SDHB loss, in contrast to SDHB retained, were younger at diagnosis, had higher rates of tumor recurrence, metastatic disease, and mortality. In addition, PGLs with SDHB loss had significantly increased expression of PCA3 compared to tumors with intact SDHB expression. Our findings suggest that specific lncRNAs may be involved in the SDHx signaling pathways in the tumorigenesis and in the development of PPGL.

Current Knowledge of Long Non-Coding RNA HOTAIR in Breast Cancer Progression and Its Application.

Breast cancer is one of the most devastating cancers with high morbidity and mortality in females worldwide. Breast tumorigenesis and further development present great uncertainty and complexity, and efficient therapeutic approaches still lack. Accumulating evidence indicates HOX transcript antisense intergenic RNA (HOTAIR) is dysregulated in cancers and has emerged as a novel hotspot in the field. In breast cancer, aberrant HOTAIR expression is responsible for advanced tumor progression by regulating multifarious signaling pathways. Besides, HOTAIR may act as competitive endogenous RNA to bind to several microRNAs and suppress their expressions, which can subsequently upregulate the levels of targeted downstream messenger RNAs, thereby leading to further cancer progression. In addition, HOTAIR works as a promising biomarker and predictor for breast cancer patients’ diagnosis or outcome prediction. Recently, HOTAIR is potentially considered to be a drug target. Here, we have summarized the induction of HOTAIR in breast cancer and its impacts on cell proliferation, migration, apoptosis, and therapeutic resistance, as well as elucidating the underlying mechanisms. This review aims to provide new insights into investigations between HOTAIR and breast cancer development and inspire new methods for studying the association in depth.

HOTAIR expression and prognostic impact in acute myeloid leukemia patients

BackgroundAcute myeloid leukemia (AML) is a disorder characterized by a rapid onset of symptoms attributable to bone marrow failure due to clonal proliferation of primitive hematopoietic stem cells or progenitor cells. Epigenetic abnormalities play an important role in the development and progression of acute leukemia. Long non-coding ribonucleic acid (lncRNA) plays an important role in epigenetic regulation. Homeobox (Hox) transcript antisense intergenic RNA (HOTAIR) is a lncRNA which has been determined to be a negative prognostic indicator in various solid-tumor patients. However, its role in hematopoietic tumors as AML is to be assessed. This study aimed at measuring lncRNA HOTAIR expression level on bone marrow (BM) mononuclear cells in newly diagnosed AML patients and correlating its expression with their outcome and different prognostic variables. This provides new prospective for a novel marker involved in development and progression of AML which can be used as a diagnostic marker and a target of therapy. The current study included 65 subjects divided into 35 newly diagnosed AML adult patients (before initiation of chemotherapy) and 30 non-leukemic adult patients who are candidates for BM aspiration for causes other than hematological malignancies as immune thrombocytopenic purpura and hypersplenism as controls. HOTAIR expression was measured on BM mononuclear cells by quantitative reverse transcription polymerase chain reaction (qRT-PCR).ResultsHOTAIR expression was found to be significantly upregulated in AML patients (probability (p) value = 0.000) and it can be used as a diagnostic biomarker of AML as confirmed by a significant difference between cases and controls using receiver operating characteristic curve (ROC) analysis. However, it was not significantly correlated with event free survival (EFS) or prognostic variables.ConclusionThis study showed that the expression of HOTAIR is upregulated in de novo AML patients and can be used as a diagnostic marker. However, highly expressed HOTAIR is not associated with poor prognosis.

LncRNA HOTAIR recruits SNAIL to inhibit the transcription of HNF4α and promote the viability, migration, invasion and EMT of colorectal cancer

Colorectal cancer causes severe burdensome on the health by its high fatality and poor prognosis. Hox transcript antisense intergenic RNA (HOTAIR) was believed closely related with the genesis and development of colorectal cancer, but the regulatory mechanism is still to be investigated. The expression of HOTAIR was analyzed in colorectal cancer using both qRT-PCR and ISH assay. The cell viability, migration, invasion and apoptosis rate were evaluated using MTT, BrdU,Transwell and flow cytometryexperiments. The interaction between HOTAIR and SNAIL was detected using RIP and RNA pull-down. The binding of SNAIL to HNF4α promoter was assessed by ChIP. The cell lines that knock down HOTAIR, SNAIL or overexpress HNF4α were constructed using retroviral vector system. The tumorigenic and metastatic capacity of colorectal cancer cells after knocking down HOTAIR were evaluated based on xenograft assay and liver metastases model. HOTAIR was highly expressed in both tissue and cell lines of colorectal cancer, indicated a regulatory function in colorectal cancer. Knock-down of HOTAIR suppressed cell viability, migration, invasion and epithelial-mesenchymal transition (EMT) of colorectal cancer cells in vitro, and inhibited the growth and metastasis of colorectal tumor in nude mice. We further found that HOTAIR suppressed HNF4α via recruiting SNAIL, and the overexpression of HNF4α inhibited cell viability, migration, invasion and EMT of colorectal cancer cells. We demonstrated that HOTAIR regulates the level of HNF4α via recruiting SNAIL, knocking down HOTAIR repressed the cell viability and metestasis of colorectal cancer cell line in vitro, and suppressed the tomorgenesis and migration/invasion of colorectal cancer in vivo.

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.

Expression of HOX transcript antisense intergenic RNA in salivary adenoid cystic carcinoma and its influence on prognosis

This study aimed to investigate the expression of HOX transcript antisense intergenic RNA (HOTAIR) in salivary adenoid cystic carcinoma (SACC) and explore its influence on prognosis. A total of 86 cases of patients with SACC who underwent surgical resection treatment from March 2007 to March 2014 were selected. In the same period, 45 cases of normal salivary gland tissues were obtained. The expression of HOTAIR was detected via real-time fluorescent quantitative polymerase chain reaction. The patients were followed up after the surgery, and the follow-up deadline was March 31, 2019. The deaths and survival times of patients were recorded. Based on the quartile value of the relative expression level of HOTAIR in SACC patients, the patients were divided into low expression group and high expression group. Kaplan-Meier method and Log-Rank test were used to compare the survival time of the two groups. Taking the age, sex, tumor location, pathological type, tumor diameter, TNM stage, nerve invasion and lymph node metastasis as independent variables, Cox proportional hazards regression model was used to analyze the multiple factors affecting survival time. The relative expression of HOTAIR in SACC tissue was 2.48±0.22, which was higher than that in normal salivary gland tissue at 1.03±0.13, and the difference was statistically significant (t=39.812, P<0.001). No nerve invasion and lymph node metastasis were observed in these patients compared with those patients with TNM stages Ⅰ or Ⅱ, while the relative expression of HOTAIR in the tissues of patients with TNM stages Ⅲ or Ⅳ, nerve invasion, and lymph node metastasis increased (P<0.05). Kaplan-Meier survival analysis showed that the average survival time and cumulative survival rate in the low expression group were higher than those in the high expression group [(113.32±10.77) months vs. (59.75±6.50) months and 72.73% vs. 39.06%, respectively, P=0.004]. Cox proportional hazard regression analysis showed that nerve invasion, lymph node metastasis, and the high expression of HOTAIR were the inde-pendent risk factors for the prognosis of patients with SACC (HR=3.274, 2.971, and 2.911, respectively, P<0.05). HOTAIR was highly expressed in patients with SACC tissues and associated with poor prognosis. It is a risk factor for prog-nosis, and it is expected to be a potential marker for the prognostic assessment of patients with SACC.

HOTAIR maintains the stemness of ovarian cancer stem cells via the miR-206/TBX3 axis

The poor prognosis of ovarian cancer is partly attributed to the frequent chemo-resistance and recurrence, which may be mediated by ovarian cancer stem cells (OCSCs). In the present study, we investigated the mechanisms contributing to the stemness of OCSCs, focusing on the long non-coding RNA HOX transcript antisense intergenic RNA (HOTAIR). Ovarian cancer cells were tested for high aldehyde dehydrogenase (ALDH) activity or high in vitro sphere-formation ability to identify OCSCs. HOTAIR was highly expressed in the OCSCs and its depletion caused a decrease in sphere-formation ability, along with reduced resistance to cisplatin and in vivo tumorigenicity. T-box transcription factor 3 (TBX3) was highly expressed in the OCSCs and was confirmed to be positively regulated by HOTAIR. Moreover, TBX3 maintained cell stemness, whereas elevating TBX3 could relieve the weakened sphere-formation ability caused by HOTAIR depletion. Subsequently, miR-206 was found to mediate the expression regulation of TBX3 by HOTAIR, and functionally involved in the regulation of stemness in OCSCs. In line with these findings, circulating HOTAIR expression was up-regulated in ovarian cancer patients. Collectively, our findings suggest that HOTAIR relieves the inhibition of TBX3 expression mediated by miR-206 in OCSCs and provide novel therapeutic targets for the treatment of ovarian cancer.

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.

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.