X-inactive Specific Transcript Research Articles

Loss of XIST lncRNA unlocks stemness and cellular plasticity in ovarian cancer

Plasticity, a key hallmark of cancer, enables cells to transition into different states, driving tumor heterogeneity. This cellular plasticity is associated with cancer progression, treatment resistance, and relapse. Cancer stem cells (CSCs) play a central role in this process, yet the molecular factors underlying cancer cell stemness remain poorly understood. In this study, we explored the role of XIST (X-inactive specific transcript) long noncoding RNA in ovarian cancer stemness and plasticity through in silico and in vitro analyses. We found that XIST is significantly down-regulated in ovarian tumors, with low XIST expression linked to a higher stemness index and lower overall survival. Knocking down XIST in ovarian cancer cells enhanced stemness, particularly increasing mesenchymal-like CSCs, and under hypoxic conditions, it promoted epithelial-like CSC markers. Our findings suggest that XIST loss leads to CSC enrichment and cellular plasticity in ovarian cancer, pointing to potential therapeutic targets for patients with low XIST expression.

Tumor cell extracellular vesicles derived long non-coding RNA X-inactive specific transcript regulates the blood–brain barrier and non-small cell lung cancer brain metastasis via miR-19b-3p/EPN2

ObjectiveTo investigate the function of tumor cell extracellular vesicles (EVs) derived long non-coding RNA X-inactive specific transcript (XIST) in non-small cell lung cancer (NSCLC) brain metastasis and to clarify its specific mechanism. MethodsEVs were isolated from A549 cells, and transmission electron microscopy, nanoparticle tracking, and western blotting were used to detect morphology and particle size of EVs. Human brain microvascular endothelial cells (HBMEC) and astrocytes were used to construct an in vitro blood–brain barrier (BBB) model. The BBB model was treated with EVs for 24 h. PKH67 staining was performed to examine EV engulfment by HBMEC and astrocytes. RT-qPCR was used to examine XIST, miR-19b-3p, and epsin 2 (EPN2) mRNA expression. Expression of EPN2 and tight junction (TJ) proteins such as claudin-5, occludin, and ZO-1 were measured using western blotting. Transepithelial electrical resistance (TEER), rhodamine-dextran, and immunofluorescence staining were performed to explore the effects of EVs and XIST on the BBB. Transwell assay was used to evaluate the invasive ability of A549 and H1299 cells. Dual-luciferase and immunoprecipitation assays were used to verify binding between miR-19b-3p, XIST, and EPN2. The Interactive Video Information System was used to observe brain metastasis of xenografts in BALB/c nude mice. ResultsA549 cell-derived EVs exhibited typical characteristics of EVs. HBMEC ingested EVs in the BBB model. EVs treatment decreased TEER and TJ protein level and increased the permeability to rhodamine-dextran. XIST was overexpressed in A549 and H1299 cells. Knockdown of XIST in A549 cell-derived EVs alleviated BBB damage and reduced NSCLC cell invasion. In vivo, XIST inhibition repressed NSCLC brain metastasis by ameliorating the BBB. Mechanistically, XIST sponged miR-19b-3p and positively regulated EPN2 expression. miR-19b-3p inhibition weakened the protective effect of XIST inhibition on the BBB. ConclusionA549 cells EVs-derived XIST inhibition ameliorates BBB injury and inhibits NSCLC brain metastasis by regulating the miR-19b-3p/EPN2 axis.

The invivo effects of knockdown of long non-coding RNA XIST on fibroid growth and gene expression.

The role of long non-coding RNAs in fibroid pathogenesis remains largely unexplored. In a previous study, we found elevated XIST (X-inactive specific transcript) levels in fibroids, which sponged miR-29c and miR-200c, leading to the overexpression of their target genes. This study aimed to assess the therapeutic potential of XIST downregulation in fibroid treatment. Ovariectomized SCID (severe combined immunodeficiency) mice were implanted with fibroid tumors transduced with XIST siRNA or a control via lentivirus. After 1 month, animals were sacrificed and the xenografts were removed for further analysis. XIST knockdown reduced tumor weight by 15% and increased miR-29c and miR-200c expression by 3.9-fold and 2.2-fold, respectively. The mRNA expression of miR-29c targets (COL3A1, TGF-β3, CDK2, SPARC) and miR-200c targets (CDK2, FN1, TDO2), as well as PRL, E2F1, and EZH2, was significantly decreased. Protein abundance of collagen, COL3A1, FN1, CDK2, SPARC, and EZH2 was also reduced. IHC analysis of xenograft sections using the markers of Ki67 for cell proliferation and cleaved caspase 3 for apoptosis showed decreased cell proliferation and no changes in apoptosis in the XIST knockdown xenografts. This analysis also revealed decreased collagen and E2F1 staining nuclei in the XIST knockdown xenografts. These results indicate that downregulation of XIST in fibroids has beneficial therapeutic effects, by reducing tumor growth and the expression of genes involved in cell proliferation, inflammation, and extracellular matrix regulation.

Comprehensive single-cell profiling of monocytes in HLA-B27-positive ankylosing spondylitis with acute anterior uveitis.

Acute anterior uveitis (AAU) is a common extra-articular manifestation of ankylosing spondylitis (AS), particularly in patients positive for the human leucocyte antigen (HLA)-B27 genetic marker. To explore the underlying mechanisms of HLA-B27+ AS-associated AAU, we employed single-cell RNA sequencing to profile the transcriptomes of peripheral blood mononuclear cells in three HLA-B27+ AS-associated AAU patients and three healthy controls (HCs). We identified 11 distinct immune cell clusters, with a particular focus on monocytes, revealing six subsets, including three previously unidentified subsets, namely, GTPase immune-associated proteins, Th17-related, and lncRNA monocytes, with unique gene expression patterns. Significant differences in monocyte composition, activation states, and gene expression were observed between patients and HCs, particularly within HLA monocyte subpopulations. Notably, enhanced expression of X-inactive specific transcript and myeloid cell nuclear differentiation antigen genes was validated across monocyte subclusters in patients. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis highlighted significant enrichment in antigen processing and presentation pathways, shedding light on the disease's molecular mechanisms. These findings provide novel insights into the molecular mechanisms of HLA-B27+ AS-associated AAU and may contribute to the development of targeted diagnostic and therapeutic strategies. Further clinical validation is essential.

Female-bias in systemic lupus erythematosus: How much is the X chromosome to blame?

Systemic lupus erythematosus (SLE or lupus) is an immune-mediated disease associated with substantial medical burden. Notably, lupus exhibits a striking female bias, with women having significantly higher susceptibility compared to men, up to 14-fold higher in some ethnicities. Supernumerary X chromosome syndromes, like Klinefelter (XXY) and Triple X syndrome (XXX), also present higher SLE prevalence, whereas Turner syndrome (XO) displays lower prevalence. Taken together, SLE prevalence in different X chromosome dosage sceneries denotes a relationship between the number of X chromosomes and the risk of developing lupus. The dosage of X-linked genes, many of which play roles in the immune system, is compensated between males and females through the inactivation of one of the two X chromosomes in female cells. X-chromosome inactivation (XCI) initiates early in development with a random selection of which X chromosome to inactivate, a choice that is then epigenetically maintained in the daughter cells. This process is regulated by the X-Inactive-Specific Transcript (XIST), encoding for a long non-coding RNA, exclusively expressed from the inactive X chromosome (Xi). XIST interacts with various RNA binding proteins and chromatin modifiers to form a ribonucleoprotein (RNP) complex responsible for the transcriptional silencing and heterochromatinization of the Xi. This ensures stable silencing of most genes on the X chromosome, with only a few genes able to escape this process. Recent findings suggest that the molecular components involved in XCI, or their dysregulation, contribute to the pathogenesis of lupus. Indeed, nonrandom XCI, elevated gene escape from XCI, and the autoimmune potential of the XIST RNP complex have been suggested to contribute to auto-immune diseases, such as lupus. This review examines these current hypotheses concerning how this dosage compensation mechanism might impact the development of lupus, shedding light on potential mechanisms underlying the pathogenesis of the disease.

Maintenance of X chromosome inactivation after T cell activation requires NF-κB signaling.

X chromosome inactivation (XCI) balances X-linked gene dosage between sexes. Unstimulated T cells lack cytological enrichment of X-inactive specific transcript (Xist) RNA and heterochromatic modifications on the inactive X chromosome (Xi), which are involved in maintenance of XCI, and these modifications return to the Xi after stimulation. Here, we examined allele-specific gene expression and epigenomic profiles of the Xi in T cells. We found that the Xi in unstimulated T cells is largely dosage compensated and enriched with the repressive H3K27me3 modification but not the H2AK119-ubiquitin (Ub) mark. Upon T cell stimulation mediated by both CD3 and CD28, the Xi accumulated H2AK119-Ub at gene regions of previous H3K27me3 enrichment. T cell receptor (TCR) engagement, specifically NF-κB signaling downstream of the TCR, was required for Xist RNA localization to the Xi. Disruption of NF-κB signaling in mouse and human T cells using genetic deletion, chemical inhibitors, and patients with immunodeficiencies prevented Xist/XIST RNA accumulation at the Xi and altered X-linked gene expression. Our findings reveal a previously undescribed connection between NF-κB signaling pathways, which affects XCI maintenance in T cells in females.

Modeling X chromosome inactivation using t5iLA naive human pluripotent stem cells

BackgroundX chromosome inactivation (XCI) is a critical epigenetic event for dosage compensation of X-linked genes in female mammals, ensuring developmental stability. A robust in vitro model is required for mimicking XCI during the early stages of embryonic development. This methodology article introduces an advanced framework for the in-depth study of XCI using human pluripotent stem cells (hPSCs). By focusing on the transition between naive and primed pluripotent states, we highlight the role of long non-coding RNA X-inactive specific transcript (XIST) and epigenetic alterations in mediating XCI.ResultsOur methodology enables the distinction between naive and primed hESCs based on XIST expression and the activity of X-linked reporters, facilitating the investigation of XCI initiation and maintenance. Through detailed experimental procedures, we demonstrate the utility of our hESC lines in modeling the process of human XCI, including the establishment of conditions for random XCI induction and the analysis of X chromosome reactivation.MethodsThe study outlines a comprehensive approach for characterizing the X chromosome status in hPSCs, employing dual fluorescent reporter hESC lines. These reporter lines enable real-time tracking of XCI dynamics through differentiation processes. We detailed protocols for the induction of X chromosome reactivation and inactivation, as well as the X status characterization methods including cultivation of hESCs, flow cytometric analysis, RNA fluorescence in situ hybridization (FISH), and transcriptome sequencing, providing a step-by-step guide for researchers to investigate XCI mechanisms in vitro.ConclusionsThis article provides a detailed, reproducible methodology for studying XCI mechanisms in vitro, employing hPSCs as a model system. It presents a significant advance in our ability to investigate XCI, offering potential applications in developmental biology, disease modeling, and regenerative medicine. By facilitating the study of XCI dynamics, this methodological framework paves the way for deeper understanding and manipulation of this fundamental biological process.

LncRNA XIST/miR-455-3p/HOXC4 axis promotes breast cancer development by activating TGF-β/SMAD signaling pathway.

Breast cancer is the second primary cause of cancer death among women. Long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) is a central regulator for X chromosome inactivation, and its abnormal expression is a primary feature of breast cancer. So far, the mechanism of XIST in breast cancer has not been fully elucidated. We attempted to illustrate the mechanism of XIST in breast cancer. The expressions of XIST, microRNA-455-3p (miR-455-3p) in breast cancer were measured using quantitative real-time PCR. The expressions of homeobox C4 (HOXC4) were assessed with immunohistochemical and Western blot. Also, the functions of XIST in breast cancer were assessed by Cell Counting Kit-8 analysis, colony formation assay, flow cytometry, Western blot, Transwell, and cell scratch assays. Meanwhile, the mechanism of XIST in breast cancer was validated using database analysis and dual-luciferase reporter assay. Furthermore, the function of XIST in breast cancer in vivo was estimated by tumor xenograft model, immunohistochemical assay, and hematoxylin-eosin staining. XIST and HOXC4 expressions were increased, but miR-455-3p expressions were decreased in breast cancer tissues and cells. Knocking down XIST restrained breast cancer cell proliferation, invasion, migration, epithelial-mesenchymal transformation (EMT), and induced cell cycle arrest at G0/G1. Meanwhile, XIST interacted with miR-455-3p, while miR-455-3p interacted with HOXC4. XIST knockdown repressed breast cancer cell proliferation, invasion, and EMT, while miR-455-3p inhibitor or HOXC4 overexpression abolished those impacts. HOXC4 overexpression also blocked the impacts of miR-455-3p mimic on breast cancer cell malignant behavior. In vivo experimental data further indicated that XIST knockdown repressed breast cancer cell tumorigenic ability, and decreased HOXC4 and p-SMAD3 (TGF-β/SMAD-related protein) expressions.XIST/miR-455-3p/HOXC4 facilitated breast cancer development by activating the TGF-β/SMAD pathway.

Human post-implantation blastocyst-like characteristics of Muse cells isolated from human umbilical cord

Muse cells, identified as cells positive for the pluripotent surface marker SSEA-3, are pluripotent-like endogenous stem cells located in the bone marrow (BM), peripheral blood, and organ connective tissues. The detailed characteristics of SSEA-3(+) cells in extraembryonic tissue, however, are unknown. Here, we demonstrated that similar to human-adult tissue-Muse cells collected from the BM, adipose tissue, and dermis as SSEA-3(+), human-umbilical cord (UC)-SSEA-3(+) cells express pluripotency markers, differentiate into triploblastic-lineage cells at a single cell level, migrate to damaged tissue, and exhibit low telomerase activity and non-tumorigenicity. Notably, ~ 20% of human-UC-SSEA-3(+) cells were negative for X-inactive specific transcript (XIST), a naïve pluripotent stem cell characteristic, whereas all human adult tissue-Muse cells are XIST-positive. Single-cell RNA sequencing revealed that the gene expression profile of human-UC-SSEA-3(+) cells was more similar to that of human post-implantation blastocysts than human-adult tissue-Muse cells. The DNA methylation level showed the same trend, and notably, the methylation levels in genes particularly related to differentiation were lower in human-UC-SSEA-3(+) cells than in human-adult tissue-Muse cells. Furthermore, human-UC-SSEA-3(+) cells newly express markers specific to extraembryonic-, germline-, and hematopoietic-lineages after differentiation induction in vitro whereas human-adult tissue-Muse cells respond only partially to the induction. Among various stem/progenitor cells in living bodies, those that exhibit properties similar to post-implantation blastocysts in a naïve state have not yet been found in humans. Easily accessible human-UC-SSEA-3(+) cells may be a valuable tool for studying early-stage human development and human reproductive medicine.

The prognostic potential of long noncoding RNA XIST in cardiovascular diseases: a review.

There is a significant mortality rate associated with cardiovascular disease despite advances in treatment. long Non-coding RNAs(lncRNAs) play a critical role in many biological processes and their dysregulation is associated with a wide range of diseases in which their downstream pathways are disrupted. A lncRNA X-inactive specific transcript (XIST) is well known as a factor that regulates the physiological process of chromosome dosage compensation for females. According to recent studies, lncRNA XIST is involved in a variety of cellular processes, including apoptosis, proliferation, invasion, metastasis, oxidative stressand inflammation, through molecular networks with microRNAs and their downstream targets in neoplastic and non-neoplastic diseases. Because these cellular processes play a role in the pathogenesis of cardiovascular diseases, we aim to investigate the role that lncRNA XIST plays in this process. Additionally, we wish to determine whether it is a prognostic factor or a potential therapeutic target in these diseases.

XIST dampens X chromosome activity in a SPEN-dependent manner during early human development.

XIST (X-inactive specific transcript) long noncoding RNA (lncRNA) is responsible for X chromosome inactivation (XCI) in placental mammals, yet it accumulates on both X chromosomes in human female preimplantation embryos without triggering X chromosome silencing. The XACT (X-active coating transcript) lncRNA coaccumulates with XIST on active X chromosomes and may antagonize XIST function. Here, we used human embryonic stem cells in a naive state of pluripotency to assess the function of XIST and XACT in shaping the X chromosome chromatin and transcriptional landscapes during preimplantation development. We show that XIST triggers the deposition of polycomb-mediated repressive histone modifications and dampens the transcription of most X-linked genes in a SPEN-dependent manner, while XACT deficiency does not significantly affect XIST activity or X-linked gene expression. Our study demonstrates that XIST is functional before XCI, confirms the existence of a transient process of X chromosome dosage compensation and reveals that XCI and dampening rely on the same set of factors.

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.

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.

Discovering therapeutic possibilities for polycystic ovary syndrome by targeting XIST and its associated ceRNA network through the analysis of transcriptome data

Long non-coding RNA (lncRNA) regulates many physiological processes by acting as competitive endogenous RNA (ceRNA). The dysregulation of lncRNA X-inactive specific transcript (XIST) has been shown in various human disorders. However, its role in the pathogenesis of polycystic ovary syndrome (PCOS) is yet to be explored. This study aimed to explore the underlying mechanism of XIST in the pathogenesis of PCOS, specifically through dataset functional analysis. GEO PCOS datasets including RNA-seq, microarray, and miRNA-seq in granulosa cells (GCs) and blood, were examined and comprehensively analyzed. Enrichment analysis, ROC curve constructions, lncRNA-miRNA-mRNA interaction network analyses, and qRT-PCR validation were performed followed by a series of drug signature screenings. Our results revealed significant dysregulation in the expression of 1131 mRNAs, 30 miRNAs, and XIST in GCs of PCOS patients compared to healthy individuals. Of the120 XIST-correlated upregulated genes, 25 were enriched in inflammation-related pathways. Additionally, 5 miRNAs were identified as negative regulators of XIST-correlated genes. Accordingly, a ceRNA network containing XIST-miRNAs-mRNAs interactions was constructed. Furthermore, 6 genes, including AQP9, ETS2, PLAU, PLEK, SOCS3, and TNFRSF1B served as both GCs and blood-based biomarkers. By analyzing the number of interactions among XIST, miRNAs, and mRNAs, we pinpointed ETS2 as the pivotal gene within the ceRNA network. Our findings reveal a novel XIST- hsa-miR-146a-5p, hsa-miR-144-3p, and hsa-miR-1271-5p-ETS2 axis that comprehensively elucidates the XIST-associated mechanism underlying PCOS onset. qRT-PCR analysis further confirmed the, overexpression of both XIST and ETS2 . Furthermore, our results demonstrated that XIST and ETS2 were correlated with some assisted reproductive technologies outcomes. Finally, we identified two novel compounds including, methotrexate/folate and threonine using drug–gene interaction databases for PCOS management. These findings provide novel insights into the molecular etiology, diagnosis, and potential therapeutic interventions for PCOS.

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.

Transcription suppression of GABARAP mediated by lncRNA XIST-EZH2 interaction triggers caspase-11-dependent inflammatory injury in ulcerative colitis

BackgroundWe have previously found that enhancer of zeste homolog 2 (EZH2) is correlated with inflammatory infiltration and mucosal cell injury in ulcerative colitis (UC). This study aims to analyze the role of X-inactive specific transcript (XIST), a possible interactive long non-coding RNA of EZH2, in UC and to explore the mechanisms. MethodsC57BL/6N mice were treated with dextran sulfate sodium (DSS), and mouse colonic mucosal epithelial cells were treated with DSS and lipopolysaccharide (LPS) for UC modeling. The UC-related symptoms in mice, and the viability and apoptosis of mucosal epithelial cells were determined. Inflammatory injury in animal and cellular models were assessed through the levels of ACS, occludin, IL-1β, IL-18, TNF-α, caspase-1, and caspase-11. Molecular interactions between XIST, EZH2, and GABA type A receptor-associated protein (GABARAP) were verified by immunoprecipitation assays, and their functions in inflammatory injury were determined by gain- or loss-of-function assays. ResultsXIST was highly expressed in DSS-treated mice and in DSS + LPS-treated mucosal epithelial cells. It recruited EZH2, which mediated gene silencing of GABARAP through H3K27me3 modification. Silencing of XIST alleviated body weight loss, colon shortening, and disease active index of mice and reduced inflammatory injuries in their colon tissues. Meanwhile, it reduced apoptosis and inflammation in mucosal epithelial cells. However, these alleviating effects were blocked by either EZH2 overexpression or GABARAP knockdown. Rescue experiments identified caspase-11 as a key effector mediating the inflammatory injury following GABARAP loss. ConclusionThis study suggests that the XIST-EZH2 interaction-mediated GABARAP inhibition activates caspase-11-dependent inflammatory injury in UC.

Long noncoding RNA XIST: a novel independent prognostic biomarker for patients with ABC-DLBCL receiving R-CHOP treatment.

Approximately one-third of activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) cases were unresponsive to standard first-line therapy; thus, identifying biomarkers to evaluate therapeutic efficacy and assessing the emergence of drug resistance is crucial. Through early-stage screening, long noncoding RNA (lncRNA) X-inactive specific transcript (XIST) was found to be correlated with the R-CHOP treatment response. This study aimed to clarify the characteristics of XIST in ABC-DLBCL. The expression level of XIST in 161 patients with ABC-DLBCL receiving R-CHOP therapy was examined via RNA in situ hybridization, and the association between XIST expression and clinicopathological features, treatment response and prognosis was analyzed in the study cohort and validated in the Gene Expression Omnibus cohort. Cell biological experiments and bioinformatics analyses were conducted to reveal aberrant signaling. The proportion of complete response in patients with high XIST expression was lower than that in patients with low XIST expression (53.8% versus 77.1%) (P = 0.002). High XIST expression was remarkably associated with the characteristics of tumor progression and was an independent prognostic element for overall survival (P = 0.039) and progression-free survival (P = 0.027) in ABC-DLBCL. XIST was proven to be involved in m6A-related methylation and ATF6-associated autophagy. XIST knockdown repressed ABC-DLBCL cellular proliferation by regulating Raf/MEK/ERK signaling. High XIST expression was associated with ABC-DLBCL tumorigenesis and development and contributed to R-CHOP treatment resistance. XIST may be a promising signal to predict ABC-DLBCL prognosis.

Long Non-coding RNA X-Inactive Specific Transcript Promotes Esophageal Squamous Cell Carcinoma Progression via the MicroRNA 34a/Zinc Finger E-box–Binding Homeobox 1 Pathway

BackgroundThe long non-coding RNA X-inactive specific transcript (XIST) plays a crucial role in transcriptional silencing of the X chromosome. Zinc finger E-box-binding homeobox 1 (ZEB1) is a transcription factor involved in epithelial-mesenchymal transition (EMT) regulation.AimsThis study aimed to investigate the impact of XIST on esophageal squamous cell carcinoma (ESCC) progression and its underlying mechanism involving the miR-34a/ZEB1/E-cadherin/EMT pathway.MethodsXIST and ZEB1 expression were analyzed using quantitative PCR and immunohistochemistry. XIST knockdown was achieved in KYSE150 ESCC cells using siRNA or shRNA lentivirus transfection. Proliferation, migration, and invasion abilities were assessed, and luciferase reporter assays were performed to confirm XIST-miR-34a-ZEB1 interactions. In vivo ESCC growth was evaluated using a xenograft mouse model.ResultsXIST and ZEB1 were upregulated in tumor tissues, correlating with metastasis and reduced survival. XIST knockdown inhibited proliferation, migration, and invasion of KYSE150 cells. It decreased ZEB1 expression, increased E-cadherin and miR-34a levels. Luciferase reporter assays confirmed miR-34a binding to XIST and ZEB1. XIST knockdown suppressed xenograft tumor growth.ConclusionXIST promotes ESCC progression via the miR-34a/ZEB1/E-cadherin/EMT pathway. Targeting the XIST/miR-34a/ZEB1 axis holds therapeutic potential and serves as a prognostic biomarker in ESCC.Graphical This study has discovered an XIST-associated pathway involved in the regulation of ZEB1 expression, thereby influencing the progression of squamous cell carcinoma (ESCC). The specific mechanism is as follows: XIST can regulates ZEB1 expression by sponging miR-34a, ultimately promoting the metastasis of tumor by down-regulating the expression of E-cadherin.

Long noncoding RNA XIST promotes cell proliferation and migration in diabetic foot ulcers through the miR-126-3p/EGFR axis

BackgroundThe prevalence of diabetic foot ulcers (DFUs) has caused serious harm to human health. To date, a highly effective treatment is lacking. Long noncoding RNA X-inactive specific transcript (lncRNA XIST) has been the subject of mounting research studies, all of which have found that it serves as a protective factor against certain diseases; however, its function in DFUs is not entirely understood. This study was performed to determine the importance of the lncRNA XIST in the pathogenesis and biological function of DFUs.MethodsDiabetic ulcer skin from rats was analysed using haematoxylin-eosin (HE), Masson’s trichrome, and immunohistochemistry (IHC) staining. The differences in the expression of genes and proteins were examined with real-time quantitative polymerase chain reaction (RT–qPCR) and Western blotting. Next, the interaction was verified with a dual luciferase gene reporter assay. In addition, CCK-8, Transwell, and wound healing assays were used to assess the proliferation and migration of HaCaT cells.ResultsThe lncRNA XIST and epidermal growth factor receptor (EGFR) were downregulated, while microRNA-126-3p (miR-126-3p) was increased in diabetic ulcer rat skin tissues and high glucose-induced HaCaT cells. In addition, we found that the lncRNA XIST binds to miR-126-3p and that EGFR is directly targeted by miR‑126‑3p. Silencing XIST contributed to upregulated miR-126-3p expression, thus lowering EGFR levels and inhibiting the proliferative and migratory abilities of high glucose-treated HaCaT cells; however, the miR-126-3p inhibitor and overexpression of EGFR reversed this effect.ConclusionDecreased lncRNA XIST expression inhibits the proliferative and migratory abilities of high glucose-induced HaCaT cells by modulating the miR-126-3p/EGFR axis, causing delayed wound healing.

Evaluation of tumor-educated platelet long non-coding RNAs (lncRNAs) as potential diagnostic biomarkers for colorectal cancer.

Cancer-derived circulating components are increasingly considered as candidate sources for non-invasive diagnostic biomarkers. This study aimed to investigate the expression of tumor-educated platelet (TEP) long non-coding RNAs (lncRNAs) in colorectal cancer (CRC) patients and determine whether it could be served as a potential tool for CRC diagnosis. Relative quantitative real-time PCR (qRT-PCR) was used to detect the expression levels of three cancer-related platelet-derived lncRNAs CCAT1, HOTTIP, and XIST in 75 CRC patients and 42 healthy controls. Quantitative data were analyzed by SPSS (IBM Corp., Armonk, NY, USA) for comparison of cancer and non-cancer individuals. The receiver operating characteristic (ROC) curve analysis was further performed to assess the diagnostic values of lncRNAs within the CRC patients. The expression levels of lncRNAs colon cancer associated transcript 1 (CCAT1) ( P = 0.006) and HOXA transcript at the distal tip (HOTTIP) ( P = 0.049), but not X-inactive specific transcript (XIST) ( P = 0.12), were significantly upregulated in CRC patients compared to healthy individuals. However, there were no significant correlations between platelet lncRNAs and clinicopathological characteristics, including sex, age, tumor location, differentiation, and size (all at P > 0.05). The area under the ROC curve (AUC) of the lncRNA CCAT1 was 0.61 (sensitivity, 71%; specificity, 50%). TEP lncRNA CCAT1 is detectable in the circulation of CRC patients and could be considered as a potential diagnostic biomarker.