Expression Of lncRNA XIST Research Articles

LncRNA XIST induces Aβ accumulation and neuroinflammation by the epigenetic repression of NEP in Alzheimer’s disease

Alzheimer’s disease (AD) is the leading cause of dementia globally, but effective treatment is lacking. We aimed to explore lncRNA XIST role in AD and the mechanisms involved in the effect of changes in lncRNA XIST on the expression of Aβ-degrading enzymes. The mouse model of AD and the cell model induced by Aβ were established. LncRNA XIST, IDE, NEP, Plasmin, ACE, EZH2 expressions and distribution of XIST in the nucleus and cytoplasm were detected by qRT-PCR. Inflammatory cytokines IL-6, IL-1β, TNFα, IL-8, and Aβ42 levels were detected by ELISA. TUNEL was used to measure brain tissue damage. Cell proliferation was detected by CCK-8 assay. Flow cytometry detected cell apoptosis. RIP validated the combination of XIST and EZH2. ChIP verified that XIST recruits EZH2 to mediate enrichment of HEK27me3 in the NEP promoter region. The protein expression in brain tissues and cells was detected by Western blot. The expression of lncRNA XIST was increased in AD mice and cell models. Inflammation and injury of nerve cells occurred in AD mice and cell models. The knockdown of lncRNA XIST alleviated Aβ-induced neuronal inflammation and damage. LncRNA XIST affected the expression of Aβ-degrading enzyme NEP, and lncRNA XIST was negatively correlated with NEP expression in AD mice. LncRNA XIST regulated NEP expression partly through epigenetic regulation by binding with EZH2. LncRNA XIST mediated neuronal inflammation and injury through epigenetic regulation of NEP. Overall, our study found that lncRNA XIST induced Aβ accumulation and neuroinflammation by the epigenetic repression of NEP in AD.

Knockdown of lncRNA XIST prevents the epithelial-mesenchymal transition of TGF-β2-induced human lens epithelial cells via miR-124/Slug axis

Posterior capsular opacification (PCO) is linked to the pathological process of lens epithelial cells, which includes proliferation, migration, and epithelial-mesenchymal transition (EMT). Our goal was to investigate whether long noncoding RNA (lncRNA) XIST contributes to EMT via targeting miR-124/Slug axis in TGF-β2-induced SRA01/04 cells. EMT was induced by stimulating SRA01/04 cells with 10 ng/mL TGF-β2 for 24 h, and PCO microenvironment was simulated. The expressions levels of lncRNA XIST, miR-124, and Slug were measured by real-time polymerase chain reaction (RT-PCR) and western blot. The role and mechanism of lncRNA XIST in promoting EMT of TGF-β2-treated SRA01/04 cells were investigated by using cell transfection, cell counting kit-8 (CCK-8), immunofluorescence staining, transwell assay, wound-healing assay, RT-PCR, western blot and dual-luciferase reporter assay. The expression of Slug and lncRNA XIST was markedly increased, while miR-124 was downregulated in TGF-β2-treated SRA01/04 cells compared with the control group. Knockdown of lncRNA XIST reduced EMT, migration, and cell viability in TGF-β2-induced SRA01/04 cells; moreover, it adversely modulated miR-124 and adjusted the expression of Slug in SRA01/04 cells, while these effects were diminished by co-transfection with AMO-miR-124. Our data demonstrated that lncRNA XIST functioned as a competitive endogenous RNA (ceRNA) of miR-124 to modulate the expression level of Slug, thereby modulating EMT, migration, and cell viability in SRA01/04 cells. In conclusion, lncRNA XIST has a crucial role in promoting TGF-β2-induced EMT via modulating the miR-124/Slug axis in SRA01/04 cells, and it may provide a novel therapeutic option for PCO treatment.

Protocatechuic aldehyde prevents ischemic injury by attenuating brain microvascular endothelial cell pyroptosis via lncRNA Xist

BackgroundPyroptosis is a pro-inflammatory cell death characterized by the formation of inflammasomes. Abnormal inflammation in brain microvascular endothelial cells (BMECs) has been correlated with ischemic stroke. Protocatechuic aldehyde (PCA) is a hydrophilic phenolic acid derived from the traditional Chinese herb Salvia miltiorrhiza with significant anti-inflammatory effects. However, the mechanism of PCA on BMEC pyroptosis under ischemic injury has been largely unexplored. PurposeWe aimed to study the effects and mechanism of PCA on BMEC pyroptosis under ischemic injury. MethodsSprague-Dawley (SD) rats were injected through the tail vein with different concentrations of PCA after transient middle cerebral artery occlusion (MCAO) was performed. The protective effects of PCA in SD rats were examined via neurological scores, infarct volume evaluation, and anti-pyroptosis effects using immunofluorescence staining and western blot. Rat BMECs (rBMECs) were treated with different concentrations of PCA after oxygen and glucose deprivation (OGD). The ability of PCA to protect rBMECs was examined via cell viability, anti-oxidative activity, and anti-pyroptosis effects as determined by qRT-PCR and western blot. Additionally, the role of lncRNA Xist in anti-pyroptosis responses of PCA-treated rBMECs was validated with lncRNA Xist siRNA. ResultsWe found that treatment with MCAO and OGD increased the expression of NOD-like receptor protein 3, gasdermin D, Caspase-1, interleukin-1β, and NIMA-related kinase 7, which was reversed by treatment with PCA or MCC950 (a pyroptosis inhibitor). In addition, PCA reduced the cerebral infarct volume in MCAO rats and promoted cell survival and proliferation in OGD/reperfusion-treated rBMECs. PCA enhanced the antioxidant activity and mitochondrial membrane potential in rBMECs. PCA also enhanced lncRNA Xist expression, and when the expression of lncRNA Xist was silenced, PCA could not alleviate pyroptosis well in rBMECs. ConclusionProtocatechuic aldehyde prevents ischemic injury by attenuating rBMEC pyroptosis via lncRNA Xist.

Lack of Salivary Long Non-Coding RNA XIST Expression Is Associated with Increased Risk of Oral Squamous Cell Carcinoma: A Cross-Sectional Study.

Studies have shown that there is a disparity between males and females in south-east Asia with regard to oral cancer morbidity. A previous study found that oral cancer tissue showed loss of heterozygosity of the X-linked lncRNA XIST gene. We suggest that XIST may play an important role in oral cancer morbidity when associated with sex. Saliva contains proteins and RNAs that are potential biomarkers for the diagnosis of diseases. This study investigated salivary XIST expression and the correlation to clinical–pathological data among oral squamous cell carcinoma patients. Salivary XIST expression was only observed in females, and a high proportion of females with OSCC lack salivary lncRNA XIST expression (88%). The expression showed no correlation with alcohol consumption, betel quid chewing, or cigarette smoking habits. People lacking salivary lncRNA XIST expression had a significantly increased odds ratio of suffering from OSCC (OR = 19.556, p < 0.001), particularly females (OR = 33.733, p < 0.001). The ROC curve showed that salivary lncRNA XIST expression has acceptable discrimination accuracy to predict the risk of OSCC (AUC = 0.73, p < 0.01). Lack of salivary lncRNA XIST expression was associated with an increased risk of OSCC. We provided an insight into the role of salivary lncRNA XIST as a biomarker to predict the morbidity of OSCC.

LncRNA XIST Relieves Hypoxia-Induced Damage in H9C2 Cells by Downregulating miR-429

This paper aimed to investigate LncRNA XIST relieving hypoxia-induced damage in H9C2 cells by downregulating miR-429. Rat H9C2 cell lines were selected and divided into a normal control group, a hypoxia group, a XIST expression group, a XIST blank expression group, a miR-429 interference group and a blank interference group. qPCR was adopted for detecting LncRNA XIST and miR-429 expression. Western blot (WB) was adopted for detecting the expression of AMPK, PDH, FAT, MCPT-1, Caspase-3, Bax and Bcl-2, ATP content, and levels of SOD, MDA and LDH. Dual luciferase reporter gene assay (DLRGA) and RNA pull-down were adopted for verifying the correlation of LncRNA XIST with miR-429. Hypoxia-induced H9C2 cells had low LncRNA XIST expression and high miR-429 expression. LncRNA XIST upregulation or miR-429 downregulation could inhibit AMPK, PDH, Caspase-3 and Bax, upregulate FAT, MCPT-1 and Bcl-2, and increase ATP content and SOD activity, as well as reduce MDA content and LDH activity. miR-429 was the target gene of LncRNA XIST. LncRNA XIST can relieve hypoxia-induced damage in H9C2 cells via binding to and downregulating miR-429

LncRNA GACAT1 targeting miRNA-149 regulates the molecular mechanism of proliferation, apoptosis and autophagy of oral squamous cell carcinoma cells.

To explore the effects of lncRNA GACAT1/miR-149 molecular axis on the proliferation, apoptosis, migration and autophagy of oral squamous cell carcinoma (OSCC) cells, and to explore its molecular mechanism. The expressions of lncRNA GACAT1 and miR-149 in tissues and cell lines of patients with OSCC were detected by qRT-PCR. Si-control, GACAT1-siRNA, inhibitor NC and miR-149 inhibitors were transfected into OSCC cells separately or in combination with Lipofectamine 2000. The binding sites between lncRNA GACAT1 and miR-149 were predicted using the miRanda website, and the targeting relationship was verified by dual-luciferase assay. The expression of lncRNA XIST and miR-149 was detected by qRT-PCR. CCK-8 assay was used to detect cell activity. Cell cycle distribution and apoptosis were detected by flow cytometry. Cell migration ability was detected by Transwell assay. The expression of migration and autophagy-related proteins was detected by western blot. LncRNA GACAT1 was highly expressed in cancer tissues and cell lines of OSCC patients (P < 0.01), while miR-149 was low expressed (P < 0.01). LncRNA GACAT1 binds to miR-149 targeting. The down-regulation of lncRNA GACAT1 inhibited the proliferation and migration of OSCC cells and promoted apoptosis and autophagy (P < 0.01). The transfection of miR-149 inhibitor had the opposite effect. Knockdown of lncRNA GACAT1 and transfection with miR-149 inhibitor reversed the effect of GACAT1 silencing on OSCC cells. Inhibition of lncRNA GACAT1 can inhibit the proliferation and migration of OSCC cells, promote apoptosis and autophagy, and the mechanism may be related to the targeting of miR-149.

LncRNA XIST upregulates TRIM25 via negatively regulating miR-192 in hepatitis B virus-related hepatocellular carcinoma

BackgroundLong non-coding RNA (lncRNA) XIST has been implicated in the progression of a variety of tumor diseases. The purpose of this study was to explore the molecular role of lncRNA XIST in human hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC).MethodsThe expression levels of lncRNA XIST, miR-192 and TRIM25 in HBV-related HCC tissues and HepG2.2.15 cells were detected by qRT-PCR. Biological information and luciferin gene reporter assay were performed to detect the interaction among lncRNA XIST, miR-192 and TRIM25. CCk-8 assay, wound healing assay and colony formation assay were conducted to detect the proliferation and migration ability of HepG2.2.15 cells.ResultsqRT-PCR results showed that the expression levels of lncRNA XIST were remarkably increased in HBV-related HCC tissues and HepG2.2.15 cells. In addition, miR-192 was a direct target gene of lncRNA XIST, and the expression of miR-192 and lncRNA XIST were negatively correlated. Moreover, overexpression of miR-192 observably inhibited the proliferation and migration of HCC cells, while overexpression of lncRNA XIST showed an opposite effect. Furthermore, TRIM25 was a direct target of miR-192, and lncRNA XIST could up-regulate the expression of TRIM25 by targeting miR-192.ConclusionLncRNA XIST could up-regulate the expression of TRIM25 by targeting and binding to miR-192, thus accelerating the occurrence and development of HCC.

Silencing of HuR Inhibits Osteosarcoma Cell Epithelial-Mesenchymal Transition via AGO2 in Association With Long Non-Coding RNA XIST

BackgroundOsteosarcoma (OS) is a highly malignant and aggressive bone tumor. This study was performed to explore the mechanisms of HuR (human antigen R) in the progression of OS.MethodsHuR expression levels in OS tissues and cells were detected by immunohistochemistry and western blotting. HuR siRNA was transfected into SJSA-1 OS cells to downregulate HuR expression, and then cell proliferation, migration, and epithelial-mesenchymal transition (EMT) were evaluated. RNA immunoprecipitation was performed to determine the association of the long non-coding RNA (lncRNA) XIST and argonaute RISC catalytic component (AGO) 2 with HuR. Fluorescence in situ hybridization analysis was performed to detect the expression of lncRNA XIST. Western blotting and immunofluorescence assays were performed to observe AGO2 expression after HuR or/and lncRNA XIST knockdown.ResultsKnockdown of HuR repressed OS cell migration and EMT. AGO2 was identified as a target of HuR and silencing of HuR decreased AGO2 expression. The lncRNA XIST was associated with HuR-mediated AGO2 suppression. Moreover, knockdown of AGO2 significantly inhibited cell proliferation, migration, and EMT in OS.ConclusionOur findings indicate that HuR knockdown suppresses OS cell EMT by regulating lncRNA XIST/AGO2 signaling.

Long Non-Coding RNA X Inactive Specific Transcript Suppressed the Proliferation and Invasion of Ovarian Cancer Cells by Restricting the Expression of Staphylococcal Nuclease Domain Containing 1

Ovarian cancer is one kind of a deadly gynecological malignancy. Recent study has shown that SND1 was associated with the development of ovarian cancer. Furthermore, the expression of lncRNA XIST in ovarian cancer was down-regulated. However, it is unclear whether lncRNA XIST could affect the occurrence and development of ovarian cancer by targeting SND1. In this study, we used the lentivirus to establish the overexpression and knockdown SND1 ovarian cancer cells. And we next detected the proliferation and invasion of these cells in diverse groups. Then, the luciferase assays were performed to detect the targeted effect of lncRNA XIST on SND1 and determined the expression of SND1 in the overexpressed lncRNA XIST ovarian cancer cells. We found that SND1 promoted the proliferation and invasion of ovarian cancer cells. And the lncRNA XIST targeted and suppressed the expression of SND1. Overexpression of lncRNA XIST inhibited the proliferation and invasion of ovarian cancer cells. However, the overexpression of SND1 alleviated the inhibitory efficacy of lncRNA XIST on the proliferation and invasion of ovarian cancer cells. LncRNA XIST inhibited the proliferation and invasion of ovarian cancer by suppressing the expression of SND1.

Total Glucosides of Paeony Alleviate Cell Apoptosis and Inflammation by Targeting the Long Noncoding RNA XIST/MicroRNA-124-3p/ITGB1 Axis in Renal Ischemia/Reperfusion Injury.

Objective Renal ischemia/reperfusion injury (RI/RI) is the main cause of acute kidney injury. Total glucosides of paeony (TGP) are a traditional Chinese medicine. This study was aimed at exploring the role of TGP in RI/RI and its underlying mechanism of action. Methods Rat RI/RI models were constructed by surgical operation. Serum creatinine (Scr) and blood urea nitrogen (BUN) were used to evaluate renal function. The levels of proinflammatory cytokines were detected by ELISA. RI/RI was simulated by hypoxia/reoxygenation (H/R) treatment in renal cells in vitro. The lncRNA XIST (XIST) expression was analyzed by qRT-PCR. Then, the viability and apoptosis of renal cells were detected by MTT and flow cytometry assay. Additionally, dual-luciferase reporter assay was used to determine the interactions among XIST, microRNA-124-3p (miR-124-3p), and ITGB1. Results TGP improved renal function and inhibited inflammatory responses after RI/RI. XIST expression was highly expressed in rat RI/RI models and H/R-treated renal cells, whereas treatment with TGP downregulated the XIST expression. Additionally, TGP increased viability and attenuated apoptosis and inflammation of H/R-treated renal cells via inhibiting XIST. Moreover, XIST was competitively bound to miR-124-3p, and ITGB1 was a target of miR-124-3p. miR-124-3p overexpression or ITGB1 inhibition rescued the reduction effect on viability and mitigated the promoting effects on cell apoptosis and inflammation caused by XIST overexpression in H/R-treated renal cells. Conclusions In vivo, TGP attenuated renal dysfunction and inflammation in RI/RI rats. In vitro, TGP inhibited XIST expression to modulate the miR-124-3p/ITGB1 axis, alleviating the apoptosis and inflammation of H/R-treated renal cells.

Silencing lncRNA XIST exhibits antiproliferative and proapoptotic effects on gastric cancer cells by up-regulating microRNA-132 and down-regulating PXN.

The present study aims to elucidate the potential therapeutic role of lncRNA XIST in gastric cancer through regulation of microRNA-132 (miR-132) and paxillin (PXN) expression. The study employed 65 gastric cancer tissue specimens and SGC7901 cell lines. Our results demonstrated that expression of lncRNA XIST and PXN was significantly elevated while the expression of miR-132 was significantly reduced in gastric cancer tissues. Dual-luciferase, RNA pull-down and RIP assays demonstrated that lncRNA XIST up-regulated the PXN expression by competitively binding to miR-132. Moreover, silencing of lncRNA XIST and up-regulation of miR-132 could suppress tumor formation ability, cell proliferation and migration, but enhanced apoptosis in gastric cancer. However, the overexpression of PXN achieved the opposite tumor-promotive effect. Meanwhile, rescue experiments suggested that silencing of lncRNA XIST could reverse the tumor-promotive effect exerted by either miR-132 inhibitor or PXN. Taken together, the present study demonstrates lncRNA XIST as a novel oncogenic lncRNA in gastric cancer, highlighting its therapeutic role in this disease.

LncRNA XIST promotes migration of Wilms' tumor cells through modulation of microRNA-193a-5p.

The aim of this study was to investigate long non-coding RNA (lncRNA) XIST expression in Wilms' tumor (WT) and to further explore its relationship with clinical features and prognosis of WT patients. Quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was carried out to examine the expression level of XIST in tumor tissue samples and paracancerous ones collected from 43 patients with renal cell carcinoma, and the interplay between XIST expression and clinical indicators, as well as prognosis of patients was analyzed. Meanwhile, XIST level in the nephroblast cancer cell line was further confirmed by qRT-PCR. In addition, XIST knockdown model was constructed using lentivirus in the WT cell lines, including HFWT and 17-94, and the influence of XIST on WT cell functions was analyzed through transwell assay. Finally, we investigated whether lncRNA XIST plays a role in the progression of WT by modulating microRNA-193a-5p. In this research, qRT-PCR results revealed a significantly higher expression of lncRNA XIST in tumor tissue specimens of patients with renal cell carcinoma than that in adjacent ones. Compared with patients with low expression of lncRNA XIST, those with high XIST expression had a higher incidence of distant metastasis and a lower overall survival rate. Compared with the negative control group, the metastatic ability of WT cells in the lncRNA XIST knockdown group was markedly weakened. In addition, the results of qPCR showed that mRNA expression of lncRNA XIST and microRNA-193a-5p were negatively correlated in renal cell carcinoma tissue specimens. At the same time, silencing microRNA-193a-5p reversed the reduced metastasis ability of WT cells induced by knockdown of XIST. LncRNA XIST expression is dramatically enhanced in WT tissues and cell lines, which is closely associated with the incidence of distant metastasis and patients' poor prognosis. In addition, we demonstrated that lncRNA XIST may accelerate the malignant progression of WT via inhibiting microRNA-193a-5p.

Expression of serum lncRNA-Xist in patients with polycystic ovary syndrome and its relationship with pregnancy outcome

ObjectiveLong non-coding RNA X-inactive specific transcript (LncRNA Xist) plays a pivotal role in various types of human diseases, while its involvement in polycystic ovary syndrome (PCOS) remains unknown. In the study we aimed to investigate if downregulate Xist expression is involved in PCOS and is correlated with adverse pregnant outcomes in PCOS. Materials and methodsIn this study, expression of lncRNA Xist in peripheral blood collected from both PCOS patients and controls were detected by qRT-PCR. Diagnostic values of Xist expression for PCOS were evaluated by ROC curve analysis. Correlation between Xist expression and pregnant outcomes of PCOS patients was analyzed. ResultsCompared with controls, Xist was significantly downregulated in patients with PCOS but not in patients with other types of diseases. Xist expression can be used to effectively distinguish PCOS patients from controls. Reduced expression level of Xist was significantly correlated with adverse pregnant outcomes of PCOS patients but not healthy controls. ConclusionThe downregulation of Xist expression may be involved in PCOS and is correlated with adverse pregnant outcomes in PCOS.

Upregulation of Long Noncoding RNA (lncRNA) X-Inactive Specific Transcript (XIST) is Associated with Cisplatin Resistance in Non-Small Cell Lung Cancer (NSCLC) by Downregulating MicroRNA-144-3p.

BackgroundPatients with advanced non-small cell lung cancer (NSCLC) treated with cisplatin, also termed cis-diamminedichloroplatinum (CDDP) or diamminedichloroplatinum (DDP), may develop chemoresistance. This study aimed to investigate the role of long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) and multidrug resistance-1 (MDR1) in tumor tissue samples and the chemoresistant human NSCLC cell lines, H460/DDP and A549/DDP, and in a murine A549/DDP tumor xenograft.Material/MethodsTissue samples were from patients with NSCLC who responded cisplatin (DDP-sensitive) (n=24), patients with NSCLC unresponsive to cisplatin (DDP-resistant) (n=30), and normal lung tissue (n=25). In H460/DDP and A549/DDP cells, expression of XIST, microRNA (miR)-144-3p, MDR1, and multidrug resistance-associated protein 1 (MRP1) were detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blot. The MTT assay measured cell survival and proliferation, a transwell assay evaluated cell migration, and flow cytometry measured apoptosis. Luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays examined the relationship between XIST and miR-144-3p. Tumor xenografts from A549/DDP cells were studied in BALB/c nude mice.ResultsIn tissue from patients with DDP-resistant NSCLC and the mouse A549/DDP tumor xenograft, lncRNA-XIST expression was upregulated and miR-144-3p expression was inhibited. In A549/DDP and H460/DDP cells, down-regulation of lncRNA-XIST and upregulation of miR-144-3p reduced cell survival, proliferation, migration, induced apoptosis and suppressed MDR1 and MRP1 expression.ConclusionsUpregulation of lncRNA-XIST was associated with cisplatin resistance in NSCLC by downregulating miRNA-144-3p in H460/DDP and A549/DDP cells, a murine A549/DDP tumor xenograft, and human tumor tissues from patients with cisplatin-resistant NSCLC.

&lt;p&gt;TCF-4 Regulated lncRNA-XIST Promotes M2 Polarization Of Macrophages And Is Associated With Lung Cancer&lt;/p&gt;

BackgroundLittle is known about the biological function of long non-coding RNA X inactive specific transcript (lncRNA XIST) and its underlying mechanism in tumor-associated macrophage (TAM) polarization of lung cancer.Materials and methodsThe expression of lncRNA XIST in macrophages was detected by RT-qPCR. The function of lncRNA XIST on IL-4-induced M2 polarization was evaluated by transfection of shRNA and RT-qPCR or Western blotting detection of M2 specific markers. Contact between T-cell-specific transcription factor 4 (TCF-4) and lncRNA XIST was verified by bioinformatics and luciferase assay. The relation between lncRNA XIST and lung cancer was determined by bioinformatics.ResultsThe expression of lncRNA XIST in THP-1-differentiated macrophages was significantly increased in M2 macrophages than M1 (P < 0.05). lncRNA XIST downregulation suppressed the IL-4-induced M2 polarization, inducing downregulation of M2 specific markers such as IL-10, Arg-1, and CD163. However, the suppression was aborted by overexpression of TCF-4. Mechanistically, lncRNA XIST was regulated by TCF-4 through direct binding. Additionally, lung cancer conditioned macrophages exhibited high expression of lncRNA XIST and lung cancer tissues highly expressed TCF-4, indicating TCF-4 regulated lncRNA XIST closely correlated with macrophage polarization and tumor progression of lung cancer.ConclusionTaken together, this study demonstrated the important role of TCF-4 regulated lncRNA XIST in regulating M2 polarization and gave a novel insight into the TAMs regulation and potential therapeutic target of lung cancer.

Down-regulation of lncRNA XIST inhibits cell proliferation via regulating miR-744/RING1 axis in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are known to be potential factors in promoting tumor progression. However, the function and mechanism of lncRNA XIST in non-small cell lung cancer (NSCLC) remains poorly understood. The expression levels of lncRNA XIST in NSCLC tissues and cell lines were detected with real-time PCR, and the correlation of the expression level of XIST with histopathological characteristics and prognosis was analyzed. The biological function of lncRNA XIST was validated through assays in vivo and in vitro The expression of lncRNA XIST was significantly up-regulated in NSCLC tissues. In addition, overexpression of XIST was positively correlated with the advanced clinical status of tumors, as well as poor overall survival and DFS. A tumor suppressive effect was presented via functional knockdown of lncRNA XIST. Up-regulation of XIST enhanced the proliferation, migration, and invasionability of NSCLC cells both in vivo and in vitro Mechanically, it was indicated that XIST could serve as an endogenous competitive RNA modulating miR-744, leading to the miR-744/RING1 signaling pathway inhibition and Wnt/β-catenin signaling pathway activation. Taken together, it was confirmed here that XIST overexpression is associated with tumor progression phenotype and the newly discovered XIST/miR-744/RING1 axis, which could serve as a potential biomarker and therapeutic target for NSCLC.

Long non-coding RNA XIST predicting advanced clinical parameters in cancer: A Meta-Analysis and case series study in a single institution.

Dysregulated expression of long non-coding RNA X-inactive specific transcript (lncRNA-XIST) has been indicated in various cancer types. In the present study, a meta-analysis was conducted to evaluate the potential role of lncRNA-XIST in predicting the clinicopathological parameters of patients with cancer. Eligible studies were obtained through a systematic search of PubMed, Web of Science, Embase and the Cochrane Library, of articles published prior to January 2019. The combined odds ratio and 95% confidence interval were calculated to determine the association between lncRNA-XIST expression and patient outcome. In addition, 45 pairs of osteosarcoma (OS) tissues and adjacent healthy tissues from a single institution were analyzed for the expression of lncRNA-XIST, and its association with clinicopathological features; ultimately, a total of 1,869 cancer patients from 25 studies were assessed. The results demonstrated that high expression levels of lncRNA-XIST were significantly associated with lymphatic metastasis, larger tumor size, advanced cancer stage and distant metastasis. However, sex was not associated with lncRNA-XIST expression level. In the OS patient cohort, it was demonstrated that lncRNA-XIST was highly expressed in OS tissues, which negatively correlated with patient prognosis. The present study indicated that lncRNA-XIST may serve as a potential biomarker for advanced clinical parameters in human cancer.

Long noncoding RNA X-inactive specific transcript as a prognostic factor in cancer patients: A meta-analysis based on retrospective studies.

Background/aims:Emerging evidence showed the long noncoding RNA X-inactive specific transcript (lncRNA XIST) may play a crucial role in various cancers. However, its prognostic value in cancer patients remains controversial. Therefore, we performed an in-depth meta-analysis to investigate the potential clinical value of lncRNA XIST as a prognostic marker for cancer patients.Methods:A comprehensive literature search was performed from PubMed, Embase and the Cochrane Central Search Library by January 2018. Pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence interval (95% Cl) were calculated to evaluate the prognosis as well as clinicopathological parameters of XIST, respectively.Results:A total of 18 retrospective studies with 1351 cancer patients were included. Current meta-analysis revealed that elevated lncRNA XIST expression was associated with poor overall survival (OS) (HR = 2.14, 95% CI = 1.26–3.64; P = .005) and disease free survival (DFS) (HR = 4.52, 95% CI = 1.42–14.37; P = .011). The clinicopathological parameters analysis demonstrated that increased XIST expression was significantly associated with tumor size (OR = 2.93, 95% CI = 2.24–3.84; P < .001), clinical stage (OR = 2.73, 95% CI = 1.62–4.58; P < .001) and lymph node metastasis (OR = 2.44, 95% CI = 1.74–3.42; P < .001). In addition, subgroup analysis based on cancer type revealed that lncRNA XIST expression correlated with distant metastasis in digestive cancer (OR = 2.90, 95% CI = 1.80–4.68; P < .001).Conclusion:The current meta-analysis results indicated lncRNA XIST expression level could serve as a prognostic predictor and biomarker in multiple cancers.

Long non-coding RNA XIST promotes TGF-β-induced epithelial-mesenchymal transition by regulating miR-367/141-ZEB2 axis in non-small-cell lung cancer

Growing evidence shows that lncRNA XIST functions as an oncogene accelerating tumor progression. Transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition (EMT) plays a key role in tumor metastasis. However, it is still unclear whether lncRNA XIST is implicated in TGF-β-induced EMT and influences cell invasion and metastasis in non-small-cell lung cancer (NSCLC). Here, we observed increased expression of lncRNA XIST and ZEB2 mRNA in metastatic NSCLC tissues. Knockdown of lncRNA XIST inhibited ZEB2 expression, and repressed TGF-β-induced EMT and NSCLC cell migration and invasion. Being in consistent with the in vitro findings, the in vivo experiment of metastasis showed that knockdown of lncRNA XIST inhibited pulmonary metastasis of NSCLC cells in mice. In addition, knockdown of ZEB2 expression can inhibit TGF-β-induced EMT and NSCLC cell migration and invasion. Mechanistically, lncRNA XIST and ZEB2 were targets of miR-367 and miR-141. Furthermore, both miR-367 and miR-141 expression can be upregulated by knockdown of lncRNA XIST. Taken together, our study reveals that lncRNA XIST can promote TGF-β-induced EMT and cell invasion and metastasis by regulating miR-367/miR-141-ZEB2 axis in NSCLC.

Long noncoding RNA XIST expedites metastasis and modulates epithelial\u2013mesenchymal transition in colorectal cancer

Tumor progression and metastasis is the main cause of death in colorectal cancer (CRC). Long noncoding RNAs (lncRNAs) are critical regulators in various diseases including human cancer. In this study, we found that lncRNA XIST was overexpressed in CRC cell lines and tissues. High expression of lncRNA XIST was associated with adverse overall survival in CRC patients. Knockdown of lncRNA XIST remarkably inhibited CRC cell proliferation, invasion, epithelial–mesenchymal transition (EMT) and CRC stem cell formation in vitro as well as tumor growth and metastasis in vivo. Further study indicated that knockdown of lncRNA XIST markedly increased the expression of microRNA-200b-3p (miR-200b-3p) that has been found to be downregulated in CRC tissues and cell lines, and luciferase activity assay indicated that lncRNA XIST could bind directly with miR-200b-3p. Moreover, knockdown of lncRNA XIST significantly reduced the expression of ZEB1, which was the direct target of miR-200b-3p, and the tumor suppressive effects caused by knockdown of lncRNA XIST could be rescued by re-expression of ZEB1 in CRC cells. Overall, our study demonstrated how lncRNA XIST regulates CRC progression and metastasis by competing for miR-200b-3p to modulate the expression of ZEB1. lncRNA XIST may be used as a biomarker to predict prognosis in CRC patients.