lncRNA XIST Research Articles

Abstract 4134148: Reduced BMPR2 in Monocytes De-represses HERV-K and Sustains Inflammation in Pulmonary Arterial Hypertension

Background&Rationale: Human endogenous retroviral (HERV) elements are embedded in 8% of our genome. They remain quiescent but can be transiently activated by viral infection to induce an interferon (IFN) response. In pulmonary arterial hypertension (PAH), HERV-K expression is elevated in myeloid cells, and thus can promote inflammation observed in pulmonary arteries (PAs) with progressive obstructive remodeling. PAH is linked to a mutation or a decrease in BMPR2 expression which our laboratory has recently shown in monocytes (MONO). HERVs are silenced by SUMOylated (S) TRIM28 (KAP1, a methylase) and SPEN (a histone deacetylase) factors that are also sequestered by the lnc RNA XIST which is increased in females to inactivate the extra X-chromosome. When TRIM28 is phosphorylated (P) by DNA-PK, it loses methylase activity and can act as a transcription factor. Hypothesis: Reduced BMPR2 in MONO results in DNA-PK mediated P-TRIM28 causing demethylation of XIST targets (X-related genes) and HERV-K thus increasing their expression. Competitive SPEN binding to the increased XIST also de-represses HERV-K . Approach: We used THP-1 MONOs with BMPR2 shRNA and induced pluripotent stem cell (i) MONOs derived from BMPR2 mutant PAH patients and assessed HERV-K , XIST , IFNs and related our findings to DNA-PK–P-TRIM28 and sequestration of SPEN. Results: XIST and HERV-K mRNA were significantly elevated in THP-1 MONOs with shBMPR2 vs. shControl and in PAH-iMONO vs. control iMONO based on gender. Reduced BMPR2 also increased IFN genes. These findings were consistent with nuclear DNA-PK and P-TRIM28 shown to bind in affinity purification mass spectrometry analysis. Bisulfite conversion assay demonstrated decreased methylation of HERV-K in BMPR2 -deficient MONOs attributed to a reduction in the methylase S-TRIM28. RNA-IP in THP-1 MONOs with shBMPR2 vs. shControl indicated increased binding of XIST with TRIM28 and SPEN, suggesting a competitive reduction in binding to HERV-K. Conclusions: Loss of BMPR2 increases XIST and HERV-K in MONO related to DNA-PK induced P-TRIM28 and reduced methylase S-TRIM28. Increased HERV-K may also be a function of the increase in XIST sequestering its deacetylase SPEN. These molecular features underlie a chronic HERV-K -IFN inflammatory response in PAH. They may explain the female predisposition to PAH, because the increase in XIST in females heightens the propensity to activate HERV-K -IFN signaling and chronic inflammation in PAs infiltrated by MONO.

Protective mechanism of Prim-O-glucosylcimifugin in the treatment of osteoarthritis: Based on lncRNA XIST regulation of Nav1.7

LncRNA XIST and Nav1.7 have been identified to be significantly associated with the onset of osteoarthritis. Prim-O-glucosylcimifugin (POG) has antiinflammatory and analgesic effects in treating osteoarthritis (OA). However, its molecular mechanism of action remains unclear. This research investigated whether POG inhibits OA cartilage degeneration by regulating Nav1.7 through lncRNA XIST. We observed the relationship between lncRNA XIST and Nav1.7 through in vivo and in vitro experiments, and utilized lentiviral plasmids for XIST overexpression to further validate the protective effect of POG against OA. In vivo experiments revealed the close association of improving OA cartilage morphological changes by POG with lncRNA XIST and Nav1.7 downregulation and related proteins expression. In vitro experiments demonstrated significantly up-regulated lncRNA XIST and Nav1.7 expression in IL1β-induced chondrocytes, and their levels and related protein expression decreased after POG intervention. FISH indicated that POG attenuated the fluorescence intensity of lncRNA XIST in chondrocytes. RT-PCR and Western blot assays revealed the positive correlation of lncRNA XIST and Nav1.7 expression in chondrocytes. Additionally, flow cytometry results revealed that POG intervention reduced OA chondrocyte apoptosis. Therefore, we conclude that POG can mediate lncRNA XIST to regulate Nav1.7 to delay cartilage degeneration, which is an effective way to treat OA. However, lncRNA XIST is not the only target for regulation, and further discussion is needed.

Significance of serum lncRNA XIST in chronic obstructive pulmonary disease and its progression to pulmonary heart disease

BackgroundChronic obstructive pulmonary disease (COPD) has become one of the major death-related causes. Chronic pulmonary heart disease (CPHD) is an adverse complication of COPD causing poor prognosis of patients. This study evaluated the role of lncRNA XIST in COPD and CPHD aiming to identify a potential biomarker for the screening and prediction of COPD.MethodsThe study enrolled 127 COPD patients, including 73 patients occurred CPHD with 76 healthy individuals as the control group. The expression of XIST was evaluated by PCR and compared between COPD patients with different severity, grades, and complications. The diagnostic and prognostic values of XIST in COPD and CPHD were assessed by ROC and Kaplan-Meier analyses.ResultsSignificant upregulation of XIST was observed in the serum of COPD patients relative to healthy individuals, which distinguished COPD patients and showed a correlation with the respiratory and pulmonary function of COPD patients. COPD patients with acute exacerbations and CPHD showed a higher expression level. Increasing serum XIST discriminated COPD patients combined CPHD and positively correlated with right ventricular hypertrophy and pulmonary hypertension. Higher serum XIST levels could indicate the adverse 3-year prognosis of COPD patients, especially for COPD patients combined with CPHD.ConclusionUpregulated XIST served as a biomarker for screening COPD and predicting adverse prognosis of COPD and COPD patients with CPHD.

LncRNA XIST/miR-381-3P/STAT1 axis as a potential biomarker for lupus nephritis.

We aim to investigate the potential roles of key genes in the development of lupus nephritis (LN), screen key biomarkers, and construct the lncRNA XIST/miR-381-3P/STAT1 axis by using bioinformatic prediction combined with clinical validation, thereby providing new targets and insights for clinical research. Gene expression microarrays GSE157293 and GSE112943 were downloaded from the GEO database to obtain differentially expressed genes (DEGs), followed by enrichment analyses on these DEGs, which were enriched and analyzed to construct a protein-protein interaction (PPI) network to screen core genes. The lncRNA-miRNA-mRNA regulatory network was predicted and constructed based on the miRNA database. 37 female patients with systemic lupus erythematosus (SLE) were recruited to validate the bioinformatics results by exploring the diagnostic value of the target ceRNA axis in LN by dual luciferase and real-time fluorescence quantitative PCR (RT-qPCR) and receiver operating characteristic (ROC). The data represented that a total of 133 differential genes were screened in the GSE157293 dataset and 2869 differential genes in the GSE112943 dataset, yielding a total of 26 differentially co-expressed genes. Six core genes (STAT1, OAS2, OAS3, IFI44, DDX60, and IFI44L) were screened. Biological functional analysis identified key relevant pathways in LN. ROC curve analysis suggested that lncRNA XIST, miR-381-3P, and STAT1 could be used as potential molecular markers to assist in the diagnosis of LN. STAT1 is a key gene in the development of LN. In conclusion, lncRNA XIST, miR-381-3P, and STAT1 can be used as new molecular markers to assist in the diagnosis of LN, and the lncRNA XIST/miR-381-3P/STAT1 axis may be a potential therapeutic target for LN.

Mechanistic study on lncRNA XIST/miR-124-3p/ITGB1 axis in renal fibrosis in obstructive nephropathy

ObjectiveThe purpose of this study was to investigate the role and possible mechanism of lncRNA XIST in renal fibrosis and to provide potential endogenous targets for renal fibrosis in obstructive nephropathy (ON). MethodsThe study included 50 cases of ON with renal fibrosis (samples taken from patients undergoing nephrectomy due to ON) and 50 cases of normal renal tissue (samples taken from patients undergoing total or partial nephrectomy due to accidental injury, congenital malformations, and benign tumors). Treatment of human proximal renal tubular epithelium (HK-2) cells with TGF-β1 simulated renal fibrosis in vitro. Cell viability and proliferation were measured by CCK-8 and EdU, and cell migration was measured by transwell. XIST, miR-124-3p, ITGB1, and epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, α-SMA, and fibronectin) were detected by PCR and immunoblot. The targeting relationship between miR-124-3p and XIST or ITGB1 was verified by starBase and dual luciferase reporter gene experiments. In addition, The left ureter was ligated in mice as a model of unilateral ureteral obstruction (UUO), and the renal histopathology was observed by HE staining and Masson staining. ResultsON patients with renal fibrosis had elevated XIST and ITGB1 levels and reduced miR-124-3p levels. The administration of TGF-β1 exhibited a dose-dependent promotion of HK-2 cell viability, proliferation, migration, and EMT. Conversely, depleting XIST or enhancing miR-124-3p hindered HK-2 cell viability, proliferation, migration, and EMT in TGF-β1-damaged HK-2 cells HK-2 cells. XIST functioned as a miR-124-3p sponge. Additionally, miR-124-3p negatively regulated ITGB1 expression. Elevating ITGB1 weakened the impact of XIST depletion on TGF-β1-damaged HK-2 cells. Down-regulating XIST improved renal fibrosis in UUO mice. ConclusionXIST promotes renal fibrosis in ON by elevating miR-124-3p and reducing ITGB1 expressions.

Diagnostic Value of lncRNA XIST in Saliva for Early Peri-Implantitis.

To analyse the relative expression and diagnostic potential of lncRNA XIST (XIST) in peri-implantitis, and explore the related mechanism of XIST in peri-implantitis. XIST expression in saliva of patients with peri-implantitis was detected by qRT-PCR. The diagnostic significance of XIST in peri-implantitis was assessed by ROC curve. Clinical indicators of the included patients were collected and the correlation between XIST levels and peri-implant indicators was determined by Pearson correlation analysis. Bioinformatic prediction and luciferase reporter assay confirmed the targeting relationship of XIST with downstream factors. Salivary XIST levels were obviously higher in patients with peri-implantitis than in the healthy control group, and the AUC value for identifying patients was 0.8742 with a sensitivity and specificity of 83.5% and 81.4%. Patients in the peri-implantitis group had higher levels of plaque index (PLI), sulcus bleeding index (SBI) and probing depth (PD) than those in the healthy control group, and the expression of XIST was positively correlated with PLI, SBI, and PD levels. In addition, miR-150-5p was confirmed to be a potential downstream target of XIST. XIST was overexpressed in the saliva of patients with peri-implantitis and correlated with the severity of the disease. XIST has high diagnostic significance for detecting peri-implantitis.

Clinical significance of lncRNA XIST expression in cholangiocarcinoma and its effect on cell migration and invasion

BackgroundCholangiocarcinoma is a malignant tumor that occurs in the bile duct system, and the prognosis of patients is poor. Currently, research suggests that long non-coding RNAs (lncRNAs) in the treatment and prevention of cholangiocarcinoma. This study primarily focuses on the regulation and potential mechanism of the lncRNA XIST (XIST) in cholangiocarcinoma. MethodsThe levels of XIST and miR-126–3p in cholangiocarcinoma tissues and cells were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell transfection status, including migration and invasion, was examined via the Transwell method. The relationship between XIST and miR-126–3p was observed by dual-luciferase gene reporter assay and verified by rescue assays. Additionally, the prognostic significance of XIST in cholangiocarcinoma was determined using Kaplan-Meier and multivariate Cox regression analyses. ResultsXIST expression was increased in cholangiocarcinoma, while miR-126–3p was decreased, in both tissues and cells. The successful construction of silencing XIST was found to inhibit the count of cell migration and invasion. XIST directly targeted miR-126–3p to regulate the progression of cholangiocarcinoma. ConclusionXIST sponging miR-126–3p inhibited the progression of cholangiocarcinoma and improved the prognosis for patients. This finding provides new insights and opportunities for future studies on cholangiocarcinoma prognostic biomarkers.

Loss of One X and the Y Chromosome Changes the Configuration of the X Inactivation Center in the Genus Tokudaia

Introduction: X chromosome inactivation (XCI) is an essential mechanism for dosage compensation between females and males in mammals. In females, XCI is controlled by a complex, conserved locus termed the X inactivation center (Xic), in which the lncRNA Xist is the key regulator. However, little is known about the Xic in species with unusual sex chromosomes. The genus Tokudaia includes three rodent species endemic to Japan. Tokudaia osimensis and Tokudaia tokunoshimensis lost the Y chromosome (XO/XO), while Tokudaia muenninki (TMU) acquired a neo-X region by fusion of the X chromosome and an autosome (XX/XY). We compared the gene location and structure in the Xic among Tokudaia species. Methods: Gene structure of nine genes in Xic was predicted, and the gene location and genome sequences of Xic were compared between mouse and Tokudaia species. The expression level of the gene was confirmed by transcripts per million calculation using RNA-seq data. Results: Compared to mouse, the Xic gene order and location were conserved in Tokudaia species. However, remarkable structure changes were observed in lncRNA genes, Xist and Tsix, in the XO/XO species. In Xist, important functional repeats, B-, C-, D-, and E-repeats, were partially or completely lost due to deletions in these species. RNA-seq data showed that female-specific expression patterns of Xist and Tsix were confirmed in TMU, however, not in the XO/XO species. Additionally, three deletions and one inversion were confirmed in the intergenic region between Jpx and Ftx in the XO/XO species. Conclusion: Our findings indicate that even if the Xist and Tsix lncRNAs are expressed, they are incapable of producing a successful and lasting XCI in the XO/XO species. We hypothesized that the significant structure change in the intergenic region of Jpx-Ftx resulted in the inability to perform the XCI, and, as a result, a lack of Xist expression. Our results collectively suggest that structural changes in the Xic occurred in the ancestral lineage of XO/XO species, likely due to the loss of one X chromosome and the Y chromosome as a consequence of the degradation of the XCI system.

How does the Xist activator Rlim/Rnf12 regulate Xist expression?

The long non-coding RNA (lncRNA) Xist is crucially involved in a process called X chromosome inactivation (XCI), the transcriptional silencing of one of the two X chromosomes in female mammals to achieve X dosage compensation between the sexes. Because Xist RNA silences the X chromosome from which it is transcribed, the activation of Xist transcription marks the initiation of the XCI process and thus, mechanisms and players that activate this gene are of central importance to the XCI process. During female mouse embryogenesis, XCI occurs in two steps. At the 2-4 cell stages imprinted XCI (iXCI) silences exclusively the paternally inherited X chromosome (Xp). While extraembryonic cells including trophoblasts keep the Xp silenced, epiblast cells that give rise to the embryo proper reactivate the Xp and undergo random XCI (rXCI) around implantation. Both iXCI and rXCI are dependent on Xist. Rlim, also known as Rnf12, is an X-linked E3 ubiquitin ligase that is involved in the transcriptional activation of Xist. However, while data on the crucial involvement of Rlim during iXCI appear clear, its role in rXCI has been controversial. This review discusses data leading to this disagreement and recent evidence for a regulatory switch of Xist transcription in epiblasts of implanting embryos, partially reconciling the roles of Rlim during Xist activation.

XIST and MUC1-C form an auto-regulatory pathway in driving cancer progression

The long non-coding RNA X-inactive specific transcript (lncRNA XIST) and MUC1 gene are dysregulated in chronic inflammation and cancer; however, there is no known interaction of their functions. The present studies demonstrate that MUC1-C regulates XIST lncRNA levels by suppressing the RBM15/B, WTAP and METTL3/14 components of the m6A methylation complex that associate with XIST A repeats. MUC1-C also suppresses the YTHDF2-CNOT1 deadenylase complex that recognizes m6A sites and contributes to XIST decay with increases in XIST stability and expression. In support of an auto-regulatory pathway, we show that XIST regulates MUC1-C expression by promoting NF-κB-mediated activation of the MUC1 gene. Of significance, MUC1-C and XIST regulate common genes associated with inflammation and stemness, including (i) miR-21 which is upregulated across pan-cancers, and (ii) TDP-43 which associates with the XIST E repeats. Our results further demonstrate that the MUC1-C/XIST pathway (i) is regulated by TDP-43, (ii) drives stemness-associated genes, and (iii) is necessary for self-renewal capacity. These findings indicate that the MUC1-C/XIST auto-regulatory axis is of importance in cancer progression.

Circulating long noncoding RNA, Zfpm2-As1, and XIST based on medical data analysis are potential plasma biomarkers for gastric cancer diagnosis.

Long noncoding RNAs (lncRNAs) participate in diseases, especially tumorigenesis, including gastric cancer (GC). Although lncRNAs in GC tissues have been extensively studied in previous research, the possible significance of circulating lncRNAs in diagnosing GC is still unknown. The present work investigated lncRNAs ZFPM2-AS1 and XIST with high expression in GC tissues proved as potential plasma biomarkers from 20 early GC cases, 100 GC cases, and 90 normal subjects. The possible correlation between ZFPM2-AS1 and XIST expression levels was analyzed with general characteristics and clinicopathological features. The performance in diagnosis was assessed according to receiver operating characteristic (ROC) analysis. According to the results, XIST and ZFPM2-AS1 expression remarkably increased within GC plasma relative to normal subjects (P< 0.01); besides, lncRNA XIST expression after surgery had a tendency of downregulation compared with preoperative levels (P< 0.05). Moreover, the area under ROC curve (AUC) values were 0.62 for ZFPM2-AS1 and 0.68 for XIST, while the pooled AUC value of CA-724 and two lncRNAs was 0.751. Circulating lncRNAs ZFPM2-AS1 and XIST can serve as the candidate plasma biomarkers used to diagnose GC.

LncRNA XIST promotes neovascularization in diabetic retinopathy by regulating miR-101-3p/VEGFA.

This study sought to investigate the regulation of long noncoding RNA (lncRNA) XIST on the microRNA (miR)-101-3p/vascular endothelial growth factor A (VEGFA) axis in neovascularization in diabetic retinopathy (DR). Serum of patients with DR was extracted for the analysis of XIST, miR-101-3p, and VEGFA expression levels. High glucose (HG)-insulted HRMECs and DR model rats were treated with lentiviral vectors. MTT, transwell, and tube formation assays were performed to evaluate cell viability, migration, and angiogenesis, and ELISA was conducted to detect the levels of inflammatory cytokines. Dual-luciferase reporter, RIP, and RNA pull-down experiments were used to validate the relationships among XIST, miR-101-3p, and VEGFA. XIST and VEGFA were upregulated and miR-101-3p was downregulated in serum from patients with DR. XIST knockdown inhibited proliferation, migration, vessel tube formation, and inflammatory responsein HG-treated HRMECs, whereas the above effects were nullified by miR-101-3p inhibition or VEGFA overexpression. miR-101-3p could bind to XIST and VEGFA. XIST promoted DR development in rats by regulating the miR-101-3p/VEGFA axis. LncRNA XIST promotes VEGFA expression by downregulating miR-101-3p, thereby stimulating angiogenesis and inflammatory response in DR.

Dysregulation of the Long Noncoding RNA X-Inactive–Specific Transcript Expression in Male Patients with Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a sex-biased disease with female gender as a significant risk factor. Recently, we reported that increased expression of the long non-coding (lnc)RNA Xist, as induced by an intersectin-1s protein fragment with proliferative potential (EHITSN), may explain the sexual dimorphism of female pulmonary artery endothelial cells (ECs) and at least in part, the imbalance sex/ratio of PAH.Xist is essential for X-chromosome inactivation and dosage compensation of X-linked genes. Increased Xist expression was also detected in a subset of ECs and lung tissue samples of male PAH patients. The role of different Xist expression levels in ECs of male PAH patients (ECPAH) was studied in several lines of male ECPAH in conjunction with molecular, biochemical, morphological, and functional approaches. Male ECPAH showed on average 10.3-fold increase in high Xist vs. low Xist, a significant association between Xist levels and their proliferative potential, and a heterogeneous methylation of the Xist/Tsix locus. Interestingly, Xist up-regulation in male ECPAH decreases the expression of Klf2, via EHITSN interaction with EZH2, the catalytic subunit of the polycomb repressive complex 2. Moreover, the studies demonstrate that EHITSN-triggered p38/Elk1/c-Fos signaling is a pathological mechanism central to ECPAH proliferation and the dynamic crosstalk with cell cycle regulatory proteins ccna1/ccnd2, and Xist-EZH2-Klf2 interaction participate directly and differentially in establishing the proliferative profile of male ECPAH.

Polysaccharides from Dendrobium officinale delay diabetic kidney disease interstitial fibrosis through LncRNA XIST/TGF-β1

PurposeRenal interstitial fibrosis is a pathological manifestation of the progression of diabetic kidney disease (DKD). Dendrobium officinale polysaccharides (DOP), one of the major active components of Dendrobium officinale, have hypoglycemic and hypolipidemic effects and are used clinically to treat diabetes. However, the role of DOP in delaying DKD progression remains unclear. This study aimed to explore the potential mechanisms by which DOP delays DKD renal interstitial fibrosis. MethodsUsing db/db mice as a model of DKD, we administered DOP by gavage and observed its therapeutic effectiveness. Employing ASO technology, we knocked down lncRNA XIST expression in kidney tissues and detected the expression of lncRNA XIST, TGF-β1, and renal interstitial fibrosis-related molecules. ResultsDOP was primarily composed of monosaccharides, with 91.57% glucose and 1.41% mannose, forming a spheroid-like structure. It has a high polydispersity index with an Mw/Mn of 6.146, and the polysaccharides are mainly connected by 4-Man(p) and 4-Glc(p) linkages. In the kidneys of db/db mice, lncRNA XIST and TGF-β1 are highly expressed; however, their expression is significantly reduced after gastric infusion with DOP, and upon knockdown of lncRNA XIST, it might delay the progression of renal interstitial fibrosis in DKD. ConclusionDOP may delay the progression of DKD renal interstitial fibrosis through the regulation of the LncRNA XIST/TGF-β1 related fibrotic pathway. This provides a new perspective for clinical strategies to delay the progression of DKD renal interstitial fibrosis.

LncRNA XIST Protects Against Polycystic Ovary Syndrome via the Regulation of miR-212-3p/RASA1 Axis.

The polycystic ovary syndrome (PCOS), a common endocrine disorder, is mainly related to infertility. Moreover, it is characterized by promoted androgen, suppressed ovulation and insulin resistance. Long non-coding RNA X inactive specific transcript (lncRNA XIST), known as an oncogene or a cancer inhabited factor, is involved in several disease. However, the diagnostic mechanisms of lncRNA XIST in PCOS have not been clarified. Our study aimed to explain whether lncRNA XIST regulates KGN cells proliferation and apoptosis via microRNA (miR)-212-3p/RASA1 axis in PCOS. Levels of lncRNA XIST, miR-212-3p and RASA1 in KGN cells were detected through reverse transcription quantitative polymerase chain reaction (RT-qPCR) assay. Fluorescence in situ Hybridization (FISH) was performed to confirm the expression of lncRNA XIST and miR-212-3p in KGN cells. StarBase and dual-luciferase reporter assay were applied for exploring the interaction between miR-212-3p and RASA1. Cell viability, apoptosis, protein expression of Bcl-2 and Bax were assessed by MTT, flow cytometry analysis, RT-qPCR and western blot, respectively. We found that lncRNA XIST was low-expressed, miR-212-3p was over-expressed, and RASA1 was dramatically down-regulated in KGN cells. LncRNA XIST negatively regulated miR-212-3p expression in KGN cells. MiR-212-3p interacted with RASA1 and negatively regulated RASA1 levels in KGN cells. Up-regulation of lncRNA XIST signally decreased cells viability, stimulated more apoptotic cells, enhanced Bax expression, and depressed Bcl-2 level in KGN cells. However, these observations were abolished after miR-212-3p mimic treatment. Furthermore, miR-212-3p inhibitor significantly inhibited cell proliferation, enhanced more apoptotic cells, increased Bax expression, and decreased Bcl-2 level in KGN cells, and these effects were eliminated by RASA1-siRNA transfection. Our observations revealed that lncRNA XIST protects against PCOS through regulating miR-212-3p/RASA1 axis, suggesting that lncRNA XIST may be a promising therapeutic target for PCOS therapy.

CAPN2 correlates with insulin resistance states in PCOS as evidenced by multi-dataset analysis

ObjectiveIR emerges as a feature in the pathophysiology of PCOS, precipitating ovulatory anomalies and endometrial dysfunctions that contribute to the infertility challenges characteristic of this condition. Despite its clinical significance, a consensus on the precise mechanisms by which IR exacerbates PCOS is still lacking. This study aims to harness bioinformatics tools to unearth key IR-associated genes in PCOS patients, providing a platform for future therapeutic research and potential intervention strategies.MethodsWe retrieved 4 datasets detailing PCOS from the GEO, and sourced IRGs from the MSigDB. We applied WGCNA to identify gene modules linked to insulin resistance, utilizing IR scores as a phenotypic marker. Gene refinement was executed through the LASSO, SVM, and Boruta feature selection algorithms. qPCR was carried out on selected samples to confirm findings. We predicted both miRNA and lncRNA targets using the ENCORI database, which facilitated the construction of a ceRNA network. Lastly, a drug-target network was derived from the CTD.ResultsThirteen genes related to insulin resistance in PCOS were identified via WGCNA analysis. LASSO, SVM, and Boruta algorithms further isolated CAPN2 as a notably upregulated gene, corroborated by biological verification. The ceRNA network involving lncRNA XIST and hsa-miR-433-3p indicated a possible regulatory link with CAPN2, supported by ENCORI database. Drug prediction analysis uncovered seven pharmacological agents, most being significant regulators of the endocrine system, as potential candidates for addressing insulin resistance in PCOS.ConclusionsThis study highlights the pivotal role of CAPN2 in insulin resistance within the context of PCOS, emphasizing its importance as both a critical biomarker and a potential therapeutic target. By identifying CAPN2, our research contributes to the expanding evidence surrounding the CAPN family, particularly CAPN10, in insulin resistance studies beyond PCOS. This work enriches our understanding of the mechanisms underlying insulin resistance, offering insights that bridge gaps in the current scientific landscape.

LncRNA XIST modulates miR-328-3p ectopic expression in lung injury induced by tobacco-specific lung carcinogen NNK both in vitro and in vivo.

It is well acknowledged that tobacco-derived lung carcinogens can induce lung injury and even lung cancer through a complex mechanism. MicroRNAs (MiRNAs) are differentially expressed in tobacco-derived carcinogen nicotine-derived nitrosamine ketone (NNK)-treated A/J mice. RNA sequencing was used to detect the level of long non-coding RNAs (lncRNAs). Murine and human lung normal and cancer cells were used to evaluate the function of lncRNA XIST and miR-328-3p in vitro, and NNK-treated A/J mice were used to test their function in vivo. In vivo levels of miR-328-3p and lncRNA XIST were analysed, using in situ hybridization. miR-328-3p agomir and lncRNA XIST-specific siRNA were used to manipulate in vivo levels of miR-328-3p and lncRNA XIST in A/J mice. LncRNA XIST was up-regulated in NNK-induced lung injury and dominated the NNK-induced ectopic miRNA expression in NNK-induced lung injury both in vitro and in vivo. Either lncRNA XIST silencing or miR-328-3p overexpression exerted opposing effects in lung normal and cancer cells regarding cell migration. LncRNA XIST down-regulated miR-328-3p levels as a miRNA sponge, and miR-328-3p targeted the 3'-UTR of FZD7 mRNA, which is ectopically overexpressed in lung cancer patients. Both in vivo lncRNA XIST silencing and miR-328 overexpression could rescue NNK-induced lung injury and aberrant overexpression of the lung cancer biomarker CK19 in NNK-treated A/J mice. Our results highlight the promotive effect of lncRNA XIST in NNK-induced lung injury and elucidate its post-transcriptional mechanisms, indicating that targeting lncRNA XIST/miR-328-3p could be a potential therapeutic strategy to prevent tobacco carcinogen-induced lung injury in vivo.

Abstract 1557: Loss of lncRNA XIST promote brain metastasis by reshaping tumor lipid metabolism via upregulation of ACSL4

Abstract Metastatic disease is the main cause of cancer death, and the brain is one of the major sites of breast tumor metastasis. The median survival of breast cancer patients who developed brain metastases (BrM) is less than a year even with the advanced treatment such as stereotactic radiosurgery (SRS). Regardless of high clinical significance, the pathological mechanism of brain metastasis is still poorly understood. Previously, we found that loss of lncRNA XIST robustly promote metastasis and specially brain metastasis in breast cancer. However, the underlying molecular mechanism was not fully understood. In following study, we found that loss of XIST has significantly altered lipid metabolism of breast cancer cells specifically increasing lipid droplet amount and PUFA incorporation. Instead of de novo syntheses, XISTlow cancer cells acquire fatty acid by uptake from exogenous. We found that one X-linked gene, Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) which are highly upregulated after loss of XIST is responsible for the altered lipid metabolism. ACSL4 activated the free polyunsaturated fatty acids (PUFAs) and lead to increased incorporation of PUFAs into phospholipids. On one hand, elevated ACLS4 expression leads to relative low PPAR pathway activation by decreasing the cellular free PUFA level which directly binds and activate PPAR. PPAR pathway is known to inhibit the expression of inflammatory cytokines which are important for cancer cells to establish brain metastasis. On the other hand, elevated ACSL4 expression enable cancer cells to metabolize the abundant PUFAs in the brain environment, thereby gaining survival advantage. However, increased PUFA incorporation into lipids especially phospholipids produce excess lipid ROS and sensitize cells to ferroptosis inducer such as RSL3. Our study has find out that brain microenvironment not only supports the outgrowth of XIST low cells by providing PUFAs for maintaining their metastatic properties but also sensitizes those cells to ferroptosis inducers, a potential therapy for treating this devastating disease. Citation Format: Yin Liu, Margaret R. Smith, Yuezhu Wang, Ralph D’Agostino, Jimmy Ruiz, Gregory L. Kucera, Lance D. Miller, Wencheng Li, Michael D. Chan, Michael Farris, Dawen Zhao, Fei Xing. Loss of lncRNA XIST promote brain metastasis by reshaping tumor lipid metabolism via upregulation of ACSL4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1557.

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

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

Inhibition of Mir-21-5p Affects the Expression of LNCRNA X-Inactive Specific Transcript and Induces Apoptosis in MCF-7 Breast Cancer Cells.

We aimed to investigate miR-21-5p inhibition effect on lncRNA-XIST expression and apoptosis status of MCF-7 cells. The MCF-7 cells were cultured and transfected by the anti-miR-21-5p oligonucleotide and expression of miR-21-5p, lncRNA-XIST, apoptosis-associated genes (bax and p53) and one miR-21-5p-unrelated lncRNA (BC200) was assessed by RT-qPCR. Furthermore, cell viability checked by MTT assay and apoptosis and cell cycle in transfected cells were detected by flow cytometry. Also, bioinformatics analysis on the transcriptome data confirmed that the lncRNA XIST might have a critical role in breast cancer (BC) cell apoptosis through ceRNAs mechanism and possible regulatory interactions with miR-21-5p. Expression of miR-21-5p and lncRNA-XIST was significantly down- and up-regulated respectively (P<0.05). However, there was no significant change in lncRNA-BC200 expression. Also, the expression of bax and p53 upraised significantly (P<0.05). In transfected cells, MTT and flow cytometry assays reported a highly significant decrease and increase in viability and apoptosis respectively. Inhibition of miR-21-5p resulted in significant upregulation of lncRNA-XIST and apoptosis-associated genes bax and p53, which led to the induction of apoptosis in MCF-7 cells. Therefore, more investigations may provide a valuable target for studies on molecular therapies for BC.