Function Of HOTAIR Research Articles

The multifaceted functions of long non-coding RNA HOTAIR in neuropathologies and its potential as a prognostic marker and therapeutic biotarget.

Long non-coding RNAs (lncRNAs) are progressively being perceived as prominent molecular agents controlling multiple aspects of neuronal (patho)physiology. Amongst these is the HOX transcript antisense intergenic RNA, often abbreviated as HOTAIR. HOTAIR epigenetically regulates its target genes via its interaction with two different chromatin-modifying agents; histone methyltransferase polycomb-repressive complex 2 and histone demethylase lysine-specific demethylase 1. Parenthetically, HOTAIR elicits trans-acting sponging function against multiple micro-RNA species. Oncological research studies have confirmed the pathogenic functions of HOTAIR in multiple cancer types, such as gliomas and proposed it as a pro-oncological lncRNA. In fact, its expression has been suggested to be a predictor of the severity/grade of gliomas, and as a prognostic biomarker. Moreover, a propound influence of HOTAIR in other aspects of brain heath and disease states is just beginning to be unravelled. The objective of this review is to recapitulate all the relevant data pertaining to the regulatory roles of HOTAIR in neuronal (patho)physiology. To this end, we discuss the pathogenic mechanisms of HOTAIR in multiple neuronal diseases, such as neurodegeneration, traumatic brain injury and neuropsychiatric disorders. Finally, we also summarize the results from the studies incriminating HOTAIR in the pathogeneses of gliomas and other brain cancers. Implications of HOTAIR serving as a suitable therapeutic target in neuropathologies are also discussed.

Downregulated lncRNA HOTAIR inhibits the proliferation of granulosa cells in endometriosis by upregulating p21.

This study was carried out to elucidate the biological function of HOTAIR in granulosa cells of endometriosis and the underlying mechanism. Granulosa cells were extracted from endometriosis patients and subjects with fallopian tube factor alone who received IVF-ET. Relative levels of HOTAIR and p21 in the extracted granulosa cells were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, HOTAIR level in endometriosis patients in stage I-II or III-IV was determined. Regulatory effects of HOTAIR on the proliferation of KGN cells were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), 5-Ethynyl-2'- deoxyuridine (EdU) and colony formation assay. Flow cytometry was conducted to evaluate the potential influence of HOTAIR on apoptosis of KGN cells. The interaction between HOTAIR and EZH2, SUV12 was detected by RNA binding protein immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assay. Finally, the potential role of the HOTAIR/p21 axis in mediating cellular behaviors of KGN cells was explored. HOTAIR was downregulated in granulosa cells extracted from endometriosis patients relative to those with fallopian tube factor alone who received IVF-ET. Knockdown of HOTAIR suppressed the proliferative ability and induced apoptosis of KGN cells. RIP and ChIP assay showed that silence of HOTAIR released EZH2 to suppress the DNA methylation of p21. Knockdown of p21 could reverse the regulatory effect of HOTAIR on the proliferative change of KGN cells. Downregulated HOTAIR suppresses the proliferative ability and induces apoptosis of granulosa cells in endometriosis by upregulating p21.

Reversal of H2O2-induced cell death by knockdown of HOTAIR in HTR-8/SVneo cells by mediation of miR-106b-5p/ACSL4 axis.

Preeclampsia is a serious threat to the health of pregnant women. Injury of trophoblasts could contribute to the progression of preeclampsia, and H2O2 was able to induce apoptosis in trophoblasts. LncRNAs have been reported to be involved in the progression of preeclampsia. Additionally, lncRNA HOTAIR is upregulated in patients with preeclampsia. However, the function of HOTAIR in H2O2-treated trophoblasts remains unclear. To explore the function of HOTAIR in preeclampsia, HTR-8/SVneo cells were stimulated with H2O2. RT-qPCR was performed to measure HOTAIR expression in HTR-8/SVneo cells. The apoptosis of HTR-8/SVneo cells was measured using TUNEL staining. The mitochondrial membrane potential was measured using JC-1 staining. Western blotting was performed to detect the expression of ACSL4, GPX4, and FTH1 in HTR-8/SVneo cells. The level of HOTAIR in HTR-8/SVneo cells was upregulated by H2O2. In addition, H2O2 notably inhibited the proliferation of HTR-8/SVneo cells, whereas knockdown of HOTAIR reversed this phenomenon. The mitochondrial membrane potential in HTR-8/SVneo cells was significantly inhibited by H2O2 and partially abolished by HOTAIR silencing. Moreover, HOTAIR could bind to miR-106b-5p; ACSL4 was identified as the downstream target of miR-106b-5p. Furthermore, HOTAIR knockdown reversed H2O2-induced ferroptosis in HTR-8/SVneo cells by regulating miR-106b-5p/ACSL4. Collectively, the knockdown of HOTAIR reversed H2O2-induced ferroptosis in HTR-8/SVneo cells by mediating miR-106b-5p/ACSL4. Thus, HOTAIR may serve as a new therapeutic target against preeclampsia.

Long Non-Coding RNA HOTAIR Promotes Human Osteosarcoma Proliferation, Migration through Activation of the Wnt/b-Catenin Signaling Pathway.

LncRNA HOTAIR exhibited different effects in human cancers. However, the role of HOTAIR was not reported in osteosarcoma. This study aimed to explore the function of HOTAIR in osteosarcoma. Firstly, we examined HOTAIR expression in breast cancer tissues by the RT-qPCR assay and examined HOTAIR protein expression via immunocytochemistry, to chemical assay, and Western blot. Then, for further exploring the function of HOTAIR, we also examined it by CCK-8 and transwell assays. Downregulation of HOTAIR was detected in osteosarcoma, which predicted poor prognosis of patients with osteosarcoma. Moreover, cell migration, invasion, and proliferation were suppressed by HOTAIR overexpression in osteosarcoma. Furthermore, LPR5 was a direct target of HOTAIR, which was upregulated in osteosarcoma. Especially, the upregulation of LPR5 could impair the suppressive effect of HOTAIR in breast cancer. HOTAIR was found to negatively regulate the EMT and Wnt/β-cadherin pathways in osteosarcoma. HOTAIR repressed the progression of osteosarcoma via regulating LPR5 and suppressing the Wnt/β-cadherin pathway. Our findings will provide a positive reference for studying the function of HOTAIR in osteosarcoma.

HOTAIR/miR1 axis acts as a potential chemotherapy target in gastric cancer

Gastric cancer is one of the most common cancers in the world. Delayed diagnosis is the most common cause of death in patients. Long noncoding RNAs (lncRNAs) are a group of non-coding RNAs that are effective in the incidence of cancers. Studies in different cancers determined HOTAIR as an important lncRNA in tumorigenesis. In gastric cancer, the function of HOTAIR in the initiation and progression of cancer seems to be crucial. In this study, we confirmed the significant differential expression of HOTAIR between gastric tumors and normal tissues in different datasets. In the following, the regulatory function of HOTAIR and its interaction with miRNAs in development of gastric cancer was analyzed. Our analysis determined that the upregulation of HOTAIR is essential to different pathways associated with the progression of gastric cancer. Further analysis determined numerous miRNAs as potential targets for HOTAIR. Among them, we demonstrated miR-1 as a significant miRNA with negative correlation with HOTAIR in gastric tumors. Validation analysis determined that HOTAIR is a target of cisplatin as a common chemotherapy drug. Eventually, the effect of cisplatin on the expression of HOTAIR and its potential target, miR-1, was checked by an in vitro study. Cisplatin treatment on the gastric cancer cell line showed that there is a significant negative correlation between the downregulation of HOTAIR and the upregulation of miR-1 in treated cells. In conclusion, comprehensive in silico analysis and experimental study provided evidence for the importance of the HOTAIR/miR-1 axis as potential diagnostic and treatment strategies for gastric cancer.

The Role and Mechanism of Long Non-Coding RNA HOTAIR in the Oncogenesis, Diagnosis, and Treatment of Head and Neck Squamous Cell Carcinoma.

The most frequent malignant tumor of the head and neck is head and neck squamous cell carcinoma (HNSCC), which has a high frequency, a poor prognosis in the late stages, and subpar therapeutic results. As a result, early HNSCC diagnosis and treatment are urgently needed; however, there are no good diagnostic biomarkers or efficient therapeutic targets at this time. The long-stranded non-coding RNA HOTAIR may be important in the pathogenesis of cancer, according to recent research. By interactions with DNA, RNA, and proteins, it has been demonstrated that HOTAIR, a >200 nucleotide RNA transcript, plays a role in the biological processes of many types of tumor cells, including proliferation, metastasis, and prognosis of HNSCC. Hence, this review discusses HOTAIR's function and molecular mechanisms in HNSCC.

A single N6-methyladenosine site regulates lncRNA HOTAIR function in breast cancer cells.

N6-methyladenosine (m6A) modification of RNA regulates normal and cancer biology, but knowledge of its function on long noncoding RNAs (lncRNAs) remains limited. Here, we reveal that m6A regulates the breast cancer-associated human lncRNA HOTAIR. Mapping m6A in breast cancer cell lines, we identify multiple m6A sites on HOTAIR, with 1 single consistently methylated site (A783) that is critical for HOTAIR-driven proliferation and invasion of triple-negative breast cancer (TNBC) cells. Methylated A783 interacts with the m6A "reader" YTHDC1, promoting chromatin association of HOTAIR, proliferation and invasion of TNBC cells, and gene repression. A783U mutant HOTAIR induces a unique antitumor gene expression profile and displays loss-of-function and antimorph behaviors by impairing and, in some cases, causing opposite gene expression changes induced by wild-type (WT) HOTAIR. Our work demonstrates how modification of 1 base in an lncRNA can elicit a distinct gene regulation mechanism and drive cancer-associated phenotypes.

Long non-coding RNA HOTAIR regulates cytoskeleton remodeling and lipid storage capacity during adipogenesis

The long non-coding RNA HOTAIR is the most differentially expressed gene between upper- and lower-body adipose tissue, yet its functional significance in adipogenesis is unclear. We report that HOTAIR expression is transiently induced during early adipogenic differentiation of gluteofemoral adipose progenitors and repressed in mature adipocytes. Upon adipogenic commitment, HOTAIR regulates protein synthesis pathways and cytoskeleton remodeling with a later impact on mature adipocyte lipid storage capacity. Our results support novel and important functions of HOTAIR in the physiological context of adipogenesis.

LncRNA HOTAIR promotes proliferation and suppresses apoptosis of mouse spermatogonium GC-1 cells by sponging miR-761 to modulate NANOS2 expression.

LncRNA HOX antisense intergenic RNA (HOTAIR) can regulate cancer-related gene expression and promote stem cell and tumor cell proliferation via mechanisms including the competing endogenous RNA (ceRNA) mechanism. HOTAIR is abundantly expressed in the genital tubercle of E11.5, E12.5, and E13.5 embryos, whereas it became barely detectable at E13.5 and expressed again in adult mouse testis. However, the underlying function and mechanism of HOTAIR in spermatogenesis have not been elucidated. Interestingly, other researchers reported that the function of gene Nanos C2HC-Type Zinc Finger 2 (nanos2) includes the maintenance of both the primordial germ cells (PGCs) and germline stem cells, and Nanos2 protein and transcripts (NANOS2) were detected only in PGCs from day E11.5 and undifferentiated spermatogonia in spermatogenesis. We therefore investigated the relationship between HOTAIR and NANOS2 in maintaining spermatogonial stem cell population. We found that, compared to the adult mouse, the expression levels of HOTAIR and NANOS2 in embryo mouse were significantly higher and miR-761expression level was lower. In mouse GC-1 spermatogonia cells, overexpression of miRNA-761 significantly inhibited the expression of NANOS2 and HOTAIR, suppressed the proliferation, and promotes apoptosis of cells. Knock down and overexpression of HOTAIR indicated that HOTAIR expression was positively correlated with NANOS2 expression; overexpressed HOTAIR could promote proliferation and suppresses apoptosis of GC-1 cells. By a rescue experiment and dual luciferase reporter assay, miR-761 was identified as a direct target of HOTAIR, and NANOS2 was identified as the direct target of miR-761. The above results indicate that HOTAIR promotes proliferation and suppresses apoptosis of mouse spermatogonium GC-1 cells by sponging miR-761 to modulate NANOS2 expression. Our findings elucidate one of possible mechanisms and importance of HOTAIR in maintaining spermatogonial stem cell population, and provide new candidate genes and possible pathogenesis for male infertility.

LncRNA-HOTAIR Inhibits H9c2 Apoptosis After Acute Myocardial Infarction via miR-206/FN1 Axis.

Although previous studies showed that long non-coding RNAs (lncRNAs) have critical roles in the pathogenesis of acute myocardial infarction (AMI), the underlying molecular mechanism that lncRNAs participate in MI remains unclear. Herein, we explored the expression of lncRNA HOX antisense non-coding RNA (HOTAIR) in the serum of MI patients and mouse model of AMI. Biological functions of HOTAIR in hypoxic H9c2 cells, the in vitro model of MI, were also assessed. RT-qPCR results showed that HOTAIR expression was downregulated in the serum of AMI patients and AMI mice. HOTAIR overexpression promoted H9c2 cell viability and inhibited cell apoptosis under hypoxic conditions. Mechanically, HOTAIR was regulated by miR-206 and FN1 was the direct target of miR-206. More importantly, miR-206 overexpression or FN1 knockdown reversed the effect of HOTAIR overexpression on H9c2 cell viability and apoptosis under hypoxic conditions. Therefore, targeting the HOTAIR/miR-206/FN1 axis may be a promising therapeutic method for MI.

Neuroprotective Effect of HOTAIR Silencing on Isoflurane-Induced Cognitive Dysfunction via Sponging microRNA-129-5p and Inhibiting Neuroinflammation

Introduction: This article purposed to detect the function of the HOTAIR and HOTAIR/microRNA-129-5p (miR-129-5p) axis on the isoflurane (ISO)-injured cells and rat, and propounded a novel perspective in exploring the molecular pathogenesis of ISO damage. Methods: The expression of HOTAIR and miR-129-5p was tested by quantitative real-time PCR. The viable cells were identified using MMT, and the apoptotic cells were provided by flow cytometry. The concentration of proinflammatory indicators was revealed by enzyme-linked immunosorbent assay kits. The function of HOTAIR on oxidative stress was detected by commercial kits. A luciferase assay was performed to confirm the relationship between miR-129-5p and HOTAIR. The Morris water maze test was conducted to elucidate the cognition of SD rats. Results: The expression of HOTAIR was enhanced and the expression of miR-129-5p was lessened in the ISO-evoked SD rats and HT22 cells. The interference of HOTAIR reversed the injury of ISO on cell viability, apoptosis, inflammation, and oxidative stress. Besides, HOTAIR might be a target ceRNA of miR-129-5p. MiR-129-5p abrogated the function of silenced HOTAIR on cell viability, cell apoptosis, inflammation, and oxidative stress. Moreover, in vivo, the intervention of HOTAIR reversed the influence of ISO on cognition and oxidative stress by binding miR-129-5p. Discussion/Conclusion: Lowly expressed HOTAIR contributed to the recovery of the ISO-injured HT22 cell model from the abnormal viability, apoptosis, inflammation, and oxidative stress by regulating miR-129-5p. miR-129-5p mediated the function of HOTAIR on cognition and oxidative balance in the ISO-managed SD rat model.

LncRNA HOTAIR influences cell proliferation via miR-130b/PTEN/AKT axis in IDD

ABSTRACT Intervertebral disc degeneration (IDD) constitutes the pathological foundation of most musculoskeletal disorders of the spine. Previous studies have noted that cell proliferation is a common feature of IDD. Bioinformatics indicated that aberrantly expressed long non-coding RNAs (lncRNAs) were involved in the development of IDD. In this study, we aimed to investigate the function of lncRNA HOTAIR in the proliferation of human nucleus pulposus (NP) cells of IDD in vitro and further clarified its mechanism. The expression of HOTAIR and miR-130b was quantified by qRT-PCR in nucleus pulposus (NP) tissues. Furthermore, NP cells proliferation were assayed by CCK8 and Immunostaining. Dual-luciferase reporter and RIP assay were used to examine the expression of HOTAIR, PTEN, and their co-target gene miR-130b. Western blotting was used to test AKT expression. Our in vitro experiments on human normal NP cells observed that HOTAIR was significantly dysregulated in IDD. Further, HOTAIR can suppress proliferation by directly targeting miR-130b. In addition, Both HOTAIR and PTEN were confirmed to target miR-130b, and miR-130b upregulation reversed the phenomenon of ectopic expression of HOTAIR. More importantly, HOTAIR upregulation significantly reduced CyclinD1 protein expression by PTEN/AKT signaling pathway. Our findings suggest that HOTAIR may bind to miR-130b and subsequently increased CyclinD1 expression via PTEN/Akt pathway. Thereby, HOTAIR could become a potential target for the treatment of IDD. Abbreviations : IDD; intervertebral disc degenerationncRNAs; non-coding RNAslncRNAs; long non-coding RNAsmiRNAs; microRNAsNP; nucleus pulposusqRT-PCR; quantitative reverse transcription–PCR LBP; Low back pain ORF; open reading frame HOTAIR; Hox transcript antisense intergenic RNA FAF1; Fas-associated protein factor-1Erk; extracellular signal-regulated kinase TUG1; Taurine Up-regulated Gene 1 HIF1A hypoxia-inducible factor 1-alpha PI3K; phosphoinositide-3 kinase AIS; adolescent idiopathic scoliosis ECM; extracellular matrix LN;lupus nephritis CT;computed tomography MRI; magnetic resonance imaging PBS; phosphate-buffered salin PBS; phosphate-buffered salin PVDF; polyvinylidene fluoride TBST; Tris-buffered saline Tween ECL; enhanced chemiluminescenceRIP; RNA immunoprecipitation

The Involvement of lncRNA HOTAIR/miR-130a-3p Axis in the Regulation of Voluntary Exercise on Cognition and Inflammation of Alzheimer's Disease.

Alzheimer's disease (AD) is an age-related neurodegenerative disease and exercises might mitigate the progression of AD. This investigation aimed to manifest the potential mechanism of exercises in AD. Morris water maze (MWM) test was conducted to evaluate the cognitive function in APP/PS1 mice. Quantitative real-time PCR was performed to detect the expression of HOTAIR and miR-130a-3p. The enzyme-linked immunosorbent assay was applied to appraise the concentration of IL-1β, IL-6, and TNF-α. A luciferase report experiment was implemented to substantiate the relationship between miR-130a-3p and HOTAIR. Exercises contributed to the elevated expression of HOTAIR. The findings of MWM implied HOTAIR inhibited the impacts of voluntary exercises on escape latency, distance moved, percentage of time spent in the target quadrant, platform crossing times, and inflammation. MiR-130a-3p mediated the function of HOTAIR on cognitive ability and inflammation. HOTAIR participated in the regulation of exercises on AD by sponging miR-130a-3p.

LncRNA HOTAIR regulates the lipid accumulation in non-alcoholic fatty liver disease via miR-130b-3p/ROCK1 axis

BackgroundExcessive hepatic lipid accumulation can lead to the occurrence of non-alcoholic fatty liver disease. Previous study showed that upregulation of lncRNA HOTAIR significantly increased total cholesterol and triglyceride. However, the function of HOTAIR in lipid accumulation during the progression NAFLD remains unclear. MethodsHigh fat diet was used to mimic NAFLD in vivo, and free fatty acid was used to establish in vitro model of NAFLD. Oil red O staining was applied to test the lipid accumulation. The pathological changes in mice were observed by H&E staining. Western blot and qRT-PCR were applied to assess protein and mRNA levels, respectively. RIP assay was used to explore the relationship among HOTAIR, miR-130b-3p and ROCK1. ResultsThe level of HOTAIR was upregulated in NAFLD. Downregulation of HOTAIR reversed lipid accumulation in FFA-treated HepG2 cells and primary hepatocytes. Meanwhile, HOTAIR bound with miR-130b-3p, and ROCK1 was identified to be the direct target of miR-130b-3p. Moreover, miR-130b-3p mimics-caused lipid accumulation decrease was reversed by pcDNA3.1-ROCK1. Furthermore, the effect of miR-130b-3p mimics on p-AMPK2α and ROCK1 level was partially reversed by ROCK1 overexpression. ConclusionKnockdown of HOTAIR significantly inhibited the progression of NAFLD through mediation of miR-130b-3p/ROCK1 axis. Our study might shed new lights on exploring new methods against NAFLD.

HOTAIR lncRNA promotes epithelial-mesenchymal transition by redistributing LSD1 at regulatory chromatin regions.

Epithelial‐to‐mesenchymal transition (EMT) describes the loss of epithelial traits and gain of mesenchymal traits by normal cells during development and by neoplastic cells during cancer metastasis. The long noncoding RNA HOTAIR triggers EMT, in part by serving as a scaffold for PRC2 and thus promoting repressive histone H3K27 methylation. In addition to PRC2, HOTAIR interacts with the LSD1 lysine demethylase, an epigenetic regulator of cell fate during development and differentiation, but little is known about the role of LSD1 in HOTAIR function during EMT. Here, we show that HOTAIR requires its LSD1‐interacting domain, but not its PRC2‐interacting domain, to promote the migration of epithelial cells. This activity is suppressed by LSD1 overexpression. LSD1‐HOTAIR interactions induce partial reprogramming of the epithelial transcriptome altering LSD1 distribution at promoter and enhancer regions. Thus, we uncover an unexpected role of HOTAIR in EMT as an LSD1 decommissioning factor, counteracting its activity in the control of epithelial identity.

The HOTAIR lncRNA: A remarkable oncogenic promoter in human cancer metastasis.

Long non-coding RNA (lncRNA) is a new type of non-coding RNA that has an important regulatory influence on several human diseases, including cancer metastasis. HOX antisense intergenic RNA (HOTAIR), a newly discovered lncRNA, has an important effect on tumour proliferation, migration and metastasis. HOTAIR regulates cell proliferation, changes gene expression, and promotes tumour cell invasion and migration. However, its molecular mechanism of action remains unknown. The present review summarizes the molecular mechanism and role of HOTAIR in tumour invasion and metastasis, discusses the association between HOTAIR and tumour metastasis through different pathways, such as the transforming growth factor β, Wnt/β-catenin, PI3K/AKT/MAPK and vascular endothelial growth factor pathways, emphasizes the function of HOTAIR in human malignant tumour metastasis and provides a foundation for its application in the diagnosis, prognosis and medical treatment of various tumours.

Long Non-coding RNA HOTAIR Function as a Competing Endogenous RNA for miR-149-5p to Promote the Cell Growth, Migration, and Invasion in Non-small Cell Lung Cancer.

Lung cancer is a leading cause of cancer death all around the world. Long non-coding RNAs (lncRNAs) have been confirmed to be involved in carcinogenesis of malignancies. However, the molecular mechanism of most lncRNAs in various kinds of cancers remains unclear. LncRNA HOTAIR and HNRNPA1 are reported to play an oncogenic role in non-small cell lung cancer, and the overexpression of HNRNPA1 is shown to promote the proliferation of lung adenocarcinoma cells. In our study, we find that the overexpression of HOTAIR could promote the proliferation and overexpression of miR-149-5p could inhibit the proliferation of lung cancer cells. Flow cytometric analysis determines that overexpression of miR-149-5p induces cell cycle arrest in the G0/G1 phases, whereas overexpression of HOTAIR decreases the proportion of G0/G1phase cells. Also, overexpression of HOTAIR promotes the migration and invasion ability of lung cancer cells, confirmed by the wound-healing and transwell assays, which are suppressed by overexpression of miR-149-5p. Furthermore, the dual-luciferase reporter assay indicates that miR-149-5p could bind both HOTAIR and the 3′UTR of HNRNPA1. In summary, we find that HOTAIR can regulate HNRNPA1 expression through a ceRNA mechanism by sequester miR-149-5p, which post-transcriptionally targets HNRNPA1, thus promoting lung cancer progression.

Emerging roles of HOTAIR in human cancer.

Long noncoding RNA HOX antisense intergenic RNA (HOTAIR) is overexpressed in many types of cancers, and substantial evidence has suggested a link between cancers and HOTAIR. In the present study, we reviewed the structure and the corresponding biologic function of HOTAIR to clarify its molecular mechanism in cancer progression. HOTAIR promotes proliferation, invasion, and migration, and inhibits apoptosis in cancer cells. HOTAIR also participates in the pathogenesis and progression of cancer by regulating inflammation and immune signaling. These findings suggested that HOTAIR is a novel biomarker in human cancers.

Exosomes-Derived Long Non-Coding RNA HOTAIR Reduces Laryngeal Cancer Radiosensitivity by Regulating microRNA-454-3p/E2F2 Axis.

BackgroundStudies have revealed exosomes are implicated in tumor microenvironment and tumorigenesis. Emerging evidence suggests long non-coding RNAs (lncRNAs) possess pivotal roles in laryngeal cancer progression. For this study, we aimed to find out the mechanism of exosomes and lncRNA HOTAIR in laryngeal cancer.MethodsLaryngeal cancer cells-derived exosomes were initially extracted, separated and identified. Flow cytometry was applied to detect apoptosis to evaluate the effect of exosomes on cell radiosensitivity. Dual luciferase reporter gene assay, RNA pull-down and RNA immunoprecipitation assays were conducted to verify the interactions among HOTAIR, microRNA (miR)-454-3p and E2F2. The gain-and-loss functions of HOTAIR or miR-454-3p were carried out to explore their effects on TU212 and LLN cell viability, apoptosis and radiosensitivity. Levels of HOTAIR, miR-454-3p and E2F2 were detected after different treatments. An in vivo analysis was carried out in mice bearing laryngeal cancer xenografts.ResultsLaryngeal cancer-derived exosomes reduced laryngeal cancer cell radiosensitivity. HOTAIR expression was increased after cells were treated with exosome, and HOTAIR overexpression reduced laryngeal cancer cell radiosensitivity. Besides, HOTAIR worked as a competing endogenous RNA (ceRNA) of miR-454-3p to regulate E2F2 in laryngeal cancer cells. In vivo results were reproduced in in vivo studies, which demonstrated that HOTAIR knockdown reduced laryngeal cancer cell radiosensitivity by sponging miR-454-3p to silence E2F2.ConclusionExosome-mediated HOTAIR acts as a ceRNA of miR-545-3p to regulate E2F2, thereby negatively regulating the radiosensitivity of laryngeal cancer cells. This study may offer novel insight into laryngeal cancer treatment.

Long non-coding RNA HOTAIR promotes exosome secretion by regulating RAB35 and SNAP23 in hepatocellular carcinoma

BackgroundEmerging evidence indicates that tumor cells release a large amount of exosomes loaded with cargos during tumorigenesis. Exosome secretion is a multi-step process regulated by certain related molecules. Long non-coding RNAs (lncRNAs) play an important role in hepatocellular carcinoma (HCC) progression. However, the role of lncRNA HOTAIR in regulating exosome secretion in HCC cells remains unclear.MethodsWe analyzed the relationship between HOTAIR expression and exosome secretion-related genes using gene set enrichment analysis (GSEA). Nanoparticle tracking analysis was performed to validate the effect of HOTAIR on exosome secretion. The transport of multivesicular bodies (MVBs) after overexpression of HOTAIR was detected by transmission electron microscopy and confocal microscopy analysis of cluster determinant 63 (CD63) with synaptosome associated protein 23 (SNAP23). The mechanism of HOTAIR’s regulation of Ras-related protein Rab-35 (RAB35), vesicle associated membrane protein 3 (VAMP3), and SNAP23 was assessed using confocal co-localization analysis, phosphorylation assays, and rescue experiments.ResultsWe found an enrichment of exosome secretion-related genes in the HOTAIR high expression group. HOTAIR promoted the release of exosomes by inducing MVB transport to the plasma membrane. HOTAIR regulated RAB35 expression and localization, which controlled the docking process. Moreover, HOTAIR facilitated the final step of fusion by influencing VAMP3 and SNAP23 colocalization. In addition, we validated that HOTAIR induced the phosphorylation of SNAP23 via mammalian target of rapamycin (mTOR) signaling.ConclusionOur study demonstrated a novel function of lncRNA HOTAIR in promoting exosome secretion from HCC cells and provided a new understanding of lncRNAs in tumor cell biology.