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Abstract Background Chronic 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. Methods The 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. Results Significant 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. Conclusion Upregulated XIST served as a biomarker for screening COPD and predicting adverse prognosis of COPD and COPD patients with CPHD.

Abstract Background The 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. Methods Diabetic 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. Results The 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. Conclusion Decreased 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.

Abstract Background Increasing evidences have shown that long non-coding RNAs (lncRNAs) display crucial regulatory roles in the occurrence and development of numerous diseases. However, the function and underlying mechanisms of lncRNAs in hypertrophy of ligamentum flavum (HLF) have not been report. Methods The integrated analysis of lncRNAs sequencing, bioinformatics analysis and real-time quantitative PCR were used to identify the key lncRNAs involved in HLF progression. Gain- and loss-function experiments were used to explore the functions of lncRNA X inactive specific transcript (XIST) in HLF. Mechanistically, bioinformatics binding site analysis, RNA pull-down, dual-luciferase reporter assay, and rescue experiments were utilized to investigate the mechanism by which XIST acts as a molecular sponge of miR-302b-3p to regulate VEGFA-mediated autophagy. Results We identified that XIST was outstandingly upregulated in HLF tissues and cells. Moreover, the up-regulation of XIST strongly correlated with the thinness and fibrosis degree of LF in LSCS patients. Functionally, knockdown of XIST drastically inhibited proliferation, anti-apoptosis, fibrosis and autophagy of HLF cells in vitro and suppressed hypertrophy and fibrosis of LF tissues in vivo. Intestinally, we uncovered that overexpression of XIST significantly promoted proliferation, anti-apoptosis and fibrosis ability of HLF cells by activating autophagy. Mechanistic studies illustrated that XIST directly medullated the VEGFA-mediated autophagy through sponging miR-302b-3p, thereby enhancing the development and progression of HLF. Conclusion Our findings highlighted that the XIST/miR-302b-3p/VEGFA-mediated autophagy axis is involved in development and progression of HLF. At the same time, this study will complement the blank of lncRNA expression profiles in HLF, which laid the foundation for further exploration of the relationship between lncRNAs and HLF in the future.

Abstract Background Long non-coding RNA X-inactive specific transcript (XIST) regulates the progression of a variety of tumors, including osteosarcoma. Bone marrow mesenchymal stem cells (BMSCs) can be recruited into osteosarcoma tissue and affect the progression by secreting exosomes. However, whether BMSCs derived exosomes transmit XIST to regulate the growth and metastasis of osteosarcoma and the related mechanism are still unclear. Method In this study, BMSCs derived exosomes were used to treat human osteosarcoma cells MG63 and 143B, and the level of XIST in BMSCs was intervened by siRNA. CCK-8, EdU, transwell assays were used to analyze the changes of cell proliferation, migration and invasion. Bioinformatics analysis, RNA pulldown and dual-luciferase reporter gene assays validated the targeted relationship of XIST with miR-655 and the interaction between miR-655 and ACLY 3’-UTR. 143B/LUC cell line was used to establish an animal model of in situ osteosarcoma to verify the found effects of XIST on osteosarcoma. Oil Red O staining, Western blot and so on were used to detect the changes of lipid deposition and protein expression. Results It was found that BMSCs derived exosomes promoted the proliferation, migration and invasion of osteosarcoma cells, and the down-regulation of XIST inhibited this effect. miR-655 mediated the role of BMSCs derived exosomal XIST in promoting the progression of osteosarcoma and down-regulation of miR-655 could reverse the effects of inhibiting XIST on the proliferation, migration and invasion of osteosarcoma cells. Meanwhile, animal level results confirmed that BMSCs derived exosomal XIST could promote osteosarcoma growth and lung metastasis by combining with miR-655. In-depth mechanism study showed that BMSCs derived exosomal XIST combined with miR-655 to increase the protein level of ACLY, which led to lipid deposition and activate β-catenin signal to promote the proliferation, migration and invasion of osteosarcoma cells. Conclusion This study showed that BMSCs derived exosomal XIST could enter osteosarcoma cells, bind and down-regulates the level of miR-655, resulting in an increase in the level of ACLY, thus increasing the lipid deposition and the activity of β-catenin signal to promote the growth and metastasis of osteosarcoma.

Abstract Background Long 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). Methods The 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. Results qRT-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. Conclusion LncRNA XIST could up-regulate the expression of TRIM25 by targeting and binding to miR-192, thus accelerating the occurrence and development of HCC.

Abstract Background Recent studies suggest that long noncoding RNAs (lncRNAs) play an important role in tumorigenesis. As a newly identified lncRNA, the role of XIST in colorectal cancer (CRC) has not been established. Here, we sought to characterize the role of XIST and its associated regulatory network in CRC cells. Methods Expression of XIST mRNA, miR-497-5p, and forkhead box k1 (FOXK1) in CRC cells and tissues were detected using quantitative real-time polymerase chain reaction (qRT-PCR). Proliferation and apoptosis of CRC cells were determined using the CCK-8 cell counting assay and flow cytometry. The rate of cell migration and invasion was determined using a transwell assay. The relationships between XIST, miR-497-5p, and FOXK1 were predicted and confirmed using a dual-luciferase reporter assay. Expression of FOXK1 protein was quantified by Western blot. Results XIST and FOXK1 expression were significantly upregulated in CRC tissues and cell lines, while miR-497-5p expression was downregulated. XIST knockdown significantly suppressed CRC cell proliferation, migration, and invasion. Silencing of XIST also reversed the downregulation of miR-497-5p and upregulation of FOXK1. Moreover, blocking XIST expression was shown to inhibit CRC tumor growth in vivo and the effects were antagonized by the loss of miR-497-5p. miR-497-5p was shown to act as a sponge of XIST and also targeted FOXK1 in CRC cells. Conclusions XIST was shown to promote the malignancy of CRC cells by competitively binding to miR-497-5p, resulting in an increase in FOXK1 expression. These results suggest that targeting of XIST may represent a possible treatment for CRC.

Abstract Background/aims The expression levels of long non-coding RNA XIST are significantly associated with paclitaxel (Pac) sensitivity in ovarian cancer, but the mechanism of action remains unclear. Therefore, this experimental design was based on lncRNA XIST analysis to regulate the effect of XIST on the tumor stem cell and paclitaxel sensitivity in ovarian cancer. Methods Sphere assay and fluorescence activated cell sorting (FACS) were used to determine the expression levels of XIST and sensitivity to paclitaxel treatment. The effect of the proliferation was detected by MTT assay. Target gene prediction and screening, luciferase reporter assays were used to validate downstream target genes for lncRNA XIS and KMT2C. The expression of KMT2C was detected by RT-qPCR and Western blotting. RT-qPCR was used to detect the expression of cancer stem cell-associated genes SOX2, OCT4 and Nanog. The tumor changes in mice were detected by in vivo experiments in nude mice. Results There was an inverse correlation between the expression of XIST and cancer stem cell (CD44 + /CD24−) population. XIST promoted methylation of histone H3 methylation at lysine 4 by enhancing the stability of lysine (K)-specific methyltransferase 2C (KMT2C) mRNA. XIST acted on the stability of KMT2C mRNA by directly targeting miR-93-5p. Overexpression of miR-93-5p can reverse the XIST overexpression-induced KMT2C decrease and sphere number increase. Overexpression of KMT2C inhibited XIST silencing-induced proliferation of cancer stem cells, and KMT2C was able to mediate paclitaxel resistance induced by XIST in ovarian cancer. The study found that XIST can affect the expression of KMT2C in the ovarian cancer via targeting miR-93-5p. Conclusion XIST promoted the sensitivity of ovarian cancer stem cells to paclitaxel in a KMT2C-dependent manner.

Abstract Background Breast cancer stem cells (BCSCs) are typically seed cells of breast tumor that initiate and maintain tumor growth. MiR-7, as a cancer inhibitor, decreases the BCSC subset and inhibits tumor progression through mechanisms that remain unknown. Methods We examined miR-7 expression in breast cancer and developed a BCSC-driven xenograft mouse model, to evaluate the effects of miR-7 overexpression on the decrease of the BCSC subset in vitro and in vivo. In addition, we determined how miR-7 decreased the BCSC subset by using the ALDEFLUOR, lentivirus infection, dual-luciferase reporter, and chromatin immunoprecipitation-PCR assays. Results MiR-7 was expressed at low levels in breast cancer tissues compared with normal tissues, and overexpression of miR-7 directly inhibited lncRNA XIST, which mediates the transcriptional silencing of genes on the X chromosome, and reduced epithelium-specific antigen (ESA) expression by increasing miR-92b and inhibiting slug. Moreover, miR-7 suppressed CD44 and ESA by directly inhibiting the NF-κB subunit RELA and slug in breast cancer cell lines and in BCSC-driven xenografts, which confirmed the antitumor activity in mice injected with miR-7 agomir or stably infected with lenti-miR-7. Conclusions The findings from this study uncover the molecular mechanisms by which miR-7 inhibits XIST, modulates the miR-92b/Slug/ESA axis, and decreases the RELA and CD44 expression, resulting in a reduced BCSC subset and breast cancer growth inhibition. These findings suggest a potentially targeted treatment approach to breast cancer.

Abstract Background MicroRNAs (miRNAs) play a pivotal role in hepatocellular carcinoma (HCC) progression and have been confirmed to participate in the carcinogenesis and development of HCC. However, the relationship between miR-497-5p and HCC remains unclear. Methods Kaplan–Meier curve analysis and the log-rank test were used to investigate the efficacy of miR-497-5p on overall survival (OS) and disease-free survival (DFS) in patients with HCC. According to in vitro experiments, programmed cell death 4 (PDCD4) was a target of miR-497-5p by the dual-luciferase activity assay. The efficacy of PDCD4 on cell proliferation and metastasis in HCC was examined by transwell assays, CCK-8 assays and reverse transcription quantitative PCR (RT-qPCR). Additionally, we conducted a luciferase activity reporter assay to confirm the interaction between lncRNA XIST and miR-49-5p. Then, to evaluate the relationship between lncRNA XIST and miR-497-5p, several mechanistic experiments, including qRT-PCR, Western blotting, transwell assays and tumor xenograft assays, were performed. Results miR-497-5p was upregulated in HCC tissues, and high expression of miR-497-5p resulted in increases in tumor size and tumor number and a higher tumor-node-metastasis (TNM) stage and Edmondson grade in patients with HCC. Silencing miR-497-5p inhibited the proliferation and migration of HCC cells. PDCD4, which was downregulated in HCC tissues, was shown to be a target of miR-497-5p and was negatively correlated with the expression of miR-497-5p. lncRNA XIST was found to act as a miR-497-5p sponge and to regulate the level of PDCD4, which is targeted by miR-497-5p. lncRNA XIST was observed to be downregulated in the HCC tissues and positively correlated with the expression of PDCD4. Conclusions Our findings reveal that the XIST/miR-497-5p/PDCD4 axis participates in HCC development and that XIST could be used as a biomarker of HCC.

Abstract Background Activation of CXCL12/CXCR4 axis has been found to be associated with invasion and metastasis in many cancers. However, the underlying mechanism remains elusive. Increasing data highlight that non-coding RNAs are linked to CRC progression. Methods The effects of CXCR4 were investigated using villin-CXCR4 transgenic mice model by flow cytometry assay, immunohistochemistry, and Western blot. The mechanism was explored through bioinformatics, luciferase reporter assay and RNA immunoprecipitation assay. Results We found that high CXCR4 expression exacerbated colitis-associated cancer in villin-CXCR4 transgenic mice. CXCR4 +/− Apc min/+ compound mutant mice demonstrated higher colorectal tumorigenesis than Apc min/+ mice. Furthermore, overexpression of CXCR4 was found to promote the epithelial-mesenchymal transition (EMT) and infiltration of myeloid-derived suppressor cells (MDSCs) and macrophages in colonic tissue, accelerating colitis-associated and Apc mutation-driven colorectal tumorigenesis and progression. Notably, miR-133a-3p was found to be significantly decreased in HCT116 cells overexpressing CXCR4 by miRNA sequencing. miR-133a-3p was proved to target RhoA, which is involved in cytoskeletal reorganization that drive cell motility. Importantly, CXCL12/CXCR4-induced upregulation of lncRNA XIST functioned as a ceRNA to sponge miR-133a-3p, thereby liberating the repression of RhoA by miR-133a-3p. The negative correlation of miR-133a-3p with RhoA was also confirmed in human CRC tissues and CXCR4 +/− mice. Conclusions Our findings revealed the critical role of CXCR4 in promoting progression of inflammatory colorectal cancer through recruiting immunocytes and enhancing cytoskeletal remodeling by lncRNA XIST/ miR-133a-3p/ RhoA signaling. These results provide novel potential therapeutic targets for hindering CXCL12/CXCR4-induced CRC progression.