lncRNA XIST interacts with miR-140 to modulate lung cancer growth by targeting iASPP

NFMCLDA: Predicting miRNA-based lncRNA-disease associations by network fusion and matrix completion

In recent years, emerging evidence has revealed a strong association between dysregulations of long non-coding RNAs (lncRNAs) and sophisticated human diseases. Biological experiments are adequate to identify such associations, but they are costly and time-consuming. Therefore, developing high-quality computational methods is a challenging and urgent task in the field of bioinformatics. This paper proposes a new lncRNA-disease association inference approach NFMCLDA (Network Fusion and Matrix Completion lncRNA-Disease Association), which can effectively integrate multi-source association data. In this approach, miRNA information is used as the transition path, and an unbalanced random walk method on three-layer heterogeneous network is adopted in the preprocessing. Therefore, more effective information between networks can be mined and the sparsity problem of the association matrix can be solved. Finally, the matrix completion method accurately predicts associations. The results show that NFMCLDA can provide more accurate lncRNA-disease associations than state-of-the-art methods. The areas under the receiver operating characteristic curves are 0.9648 and 0.9713, respectively, through the cross-validation of 5-fold and 10-fold. Data from published case studies on four diseases - lung cancer, osteosarcoma, cervical cancer, and colon cancer - have confirmed the reliable predictive potential of NFMCLDA model.

Potential roles of lncRNA-XIST/miRNAs/mRNAs in human cancer cells

Long non-coding RNAs (lncRNAs) are non-coding RNAs that contain more than 200 nucleotides but do not code for proteins. In tumorigenesis, lncRNAs can have both oncogenic and tumor-suppressive properties. X inactive-specific transcript (XIST) is a known lncRNA that has been implicated in X chromosome silencing in female cells. Dysregulation of XIST is associated with an increased risk of various cancers. Therefore, XIST can be a beneficial prognostic biomarker for human malignancies. In this review, we attempt to summarize the emerging roles of XIST in human cancers.

lncRNA XIST/miR‑129‑2‑3p axis targets CCP110 to regulate the proliferation, invasion and migration of endometrial cancer cells

Centromere coiled-coil protein 110 (CCP110) plays a role in the development of several types of cancer; however, its regulatory mechanism and role in endometrial cancer is unclear. The present study revealed that CCP110 is regulated by a signaling pathway involving microRNA (miR/miRNA)-129-2-3p and the long non-coding RNA (lncRNA) X-inactive-specific transcript (XIST), and plays a role in controlling the proliferation, migration and invasion of endometrial cancer cells. CCP110 was upregulated in human endometrial cancer tissues, as revealed by immunohistochemistry, and high expression of the protein was related to reduced overall survival of the patients. Genetic knockdown of CCP110 by small interfering RNA promoted apoptosis and suppressed the proliferation, migration, invasion and colony formation of endometrial cancer cells significantly in the endometrial cancer Ishikawa and HEC-1B cell lines, as assessed by flow cytometry, and Cell Counting Kit-8, Transwell and colony formation assays. A bioinformatics analysis and luciferase reporter assay revealed that CCP110 is a target of miR-129-2-3p. Overexpression of miR-129-2-3p mimic fragments inhibited the proliferation, migration and invasion of endometrial cancer cells significantly, while co-overexpression of CCP110 counteracted these inhibitory effects. The expression level of the lncRNA XIST was upregulated significantly in endometrial cancer tissues, as assessed by reverse transcription-quantitative PCR assay, while that of miR-129-2-3p was downregulated significantly. A bioinformatics analysis and luciferase reporter assay showed that XIST could inhibit miR-129-2-3p via a miRNA sponge effect. Furthermore, co-overexpression of XIST antagonized the inhibitory effect of the miR-129-2-3p mimic on the luciferase reporter gene signal and protein expression of CCP110. Co-overexpression of XIST also abolished the inhibitory effect of the miR-129-2-3p mimic on the proliferation, migration and invasion of endometrial cancer cells. Overall, these data identified a novel regulatory mechanism of CCP110 involving XIST and miR-129-2-3p, which affected the development of endometrial carcinoma. CCP110, XIST and miR-129-2-3p could represent novel targets for the clinical treatment of endometrial cancer.

Mechanism and function of miR-140 in human cancers: A review and in silico study

MicroRNA-140 (miR-140) acts as a tumor suppressor and plays a vital role in cell biological functions such as cell proliferation, apoptosis, and DNA repair. The expression of this miRNA has been shown to be considerably decreased in cancer tissues and cell lines compared with normal adjacent tissues. Consequently, aberrant expression of some miR-140 target genes can lead to the initiation and progression of various human cancers, such as breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. The dysregulation of the miR-140 network also affects cell proliferation, invasion, metastasis, and apoptosis of cancer cells by affecting various signaling pathways. Besides, up-regulation of miR-140 could enhance the efficacy of chemotherapeutic agents in different cancer. We aimed to cover most aspects of miR-140 function in cancer development and address its importance in different stages of cancer progression.

Cucurbitacin B regulates lung cancer cell proliferation and apoptosis via inhibiting the IL-6/STAT3 pathway through the lncRNA XIST/miR-let-7c axis

CONTEXT

Lung cancer, the most common type of cancer, has a high mortality rate. Cucurbitacin B (CuB), a natural compound extracted from Cucurbitaceae plants, has antitumor effects.

OBJECTIVE

We investigated the role of CuB on lung cancer and its potential mechanisms.

MATERIALS AND METHODS

A549 cells were treated with 0.1, 0.3, 0.6, and 0.9 μM CuB for 12, 24, and 48 h or untreated. Gene and protein levels were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting. Enzyme-linked immunosorbent assay (ELISA) detected inflammatory factors levels (TNF-α and IL-10). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and colony formation assays measured cell viability, apoptosis, and proliferation. The interaction between miR-let-7c and long non-coding RNA X inactive-specific transcript (XIST) or interleukin-6 (IL-6) was verified by dual-luciferase reporter assays.

RESULTS

CuB treatment inhibited the proliferation of lung cancer cells and promoted cell apoptosis, and increased the expression of Bax and cleaved caspase3, decreased cyclin B1 and Bcl-2 expression. CuB suppressed XIST and IL-6 expression, and enhanced miR-let-7c expression. XIST silencing enhanced the inhibitory effect of CuB on cell proliferation and the promotion effect on apoptosis via upregulating miR-let-7c. Moreover, XIST targeted miR-let-7c to activate the IL-6/STAT axis. MiR-let-7c overexpression enhanced the regulatory effect of CuB on proliferation and apoptosis via suppressing the IL-6/STAT3 pathway.

DISCUSSION AND CONCLUSION

CuB regulated cell proliferation and apoptosis by inhibiting the XIST/miR-let-7c/IL-6/STAT3 axis in lung cancer. These findings indicate CuB may have the possibility of clinical application in lung cancer treatment.

XIST silencing alleviated inflammation and mesangial cells proliferation in diabetic nephropathy by sponging miR-485

In this study, we investigated the role of XIST in the development of diabetic nephropathy (DN) and further explored its underlying mechanism. qRT-PCR was used to examine the level of XIST in serum of DN patients. ELISA, MTT, and flow cytometry were used to investigate the effect of XIST on biological functions of human mesangial cells (HMCs) treated with high glucose. The recovery experiments were used to explore the potential mechanism. The result showed XIST expression was elevated significantly in serums of DN patients. XIST silencing alleviated the induction of high glucose in biological behaviour of HMCs. Besides, miR-485 inhibitor revised the suppression by si-XIST in biological behaviour of high glucose induced HMCs. Furthermore, PSMB8 mimic relieved the inhibition of si-XIST in biological behaviour of high glucose induced HMCs. In short, XIST silencing could alleviate biological process and inflammation of HMCs treated with high glucose by sponging miR-485.

Epigenetic regulation in myocardial infarction: Non-coding RNAs and exosomal non-coding RNAs

Myocardial infarction (MI) is one of the leading causes of deaths globally. The early diagnosis of MI lowers the rate of subsequent complications and maximizes the benefits of cardiovascular interventions. Many efforts have been made to explore new therapeutic targets for MI, and the therapeutic potential of non-coding RNAs (ncRNAs) is one good example. NcRNAs are a group of RNAs with many different subgroups, but they are not translated into proteins. MicroRNAs (miRNAs) are the most studied type of ncRNAs, and have been found to regulate several pathological processes in MI, including cardiomyocyte inflammation, apoptosis, angiogenesis, and fibrosis. These processes can also be modulated by circular RNAs and long ncRNAs via different mechanisms. However, the regulatory role of ncRNAs and their underlying mechanisms in MI are underexplored. Exosomes play a crucial role in communication between cells, and can affect both homeostasis and disease conditions. Exosomal ncRNAs have been shown to affect many biological functions. Tissue-specific changes in exosomal ncRNAs contribute to aging, tissue dysfunction, and human diseases. Here we provide a comprehensive review of recent findings on epigenetic changes in cardiovascular diseases as well as the role of ncRNAs and exosomal ncRNAs in MI, focusing on their function, diagnostic and prognostic significance.

XIST in Brain Cancer

Long non-coding RNAs (lncRNAs) make up the majority of the human genome. They are a group of small RNA molecules that do not code for any proteins but play a primary role in regulating a variety of physiological and pathological processes. X-inactive specific transcript (XIST), one of the first lncRNAs to be discovered, is chiefly responsible for X chromosome inactivation: an evolutionary process of dosage compensation between the sex chromosomes of males and females. Recent studies show that XIST plays a pathophysiological role in the development and prognosis of brain tumors, a heterogeneous group of neoplasms that cause significant morbidity and mortality. In this review, we explore recent advancements in the role of XIST in migration, proliferation, angiogenesis, chemoresistance, and evasion of apoptosis in different types of brain tumors, with particular emphasis on gliomas.

Regulatory Mechanism of MicroRNA-9 / Long Non-Coding RNA XIST Expression on Mouse Macrophage RAW264.7 Apoptosis Induced by Oxidized Low Density Lipoprotein

It aims to analyze the influential mechanism of microRNA-9 (miR-9) and long non-coding RNA XIST (lncRNA XIST) expression on the proliferation and apoptosis of macrophages induced by oxidized-low density lipoprotein (ox-LDL). Firstly, lncRNA XIST overexpression vector was constructed, and then RAW264.7 cells were used as the research object. Methylthiazolyl tetrazolium (MTT) method, flow cytometry, and Western blot were used to detect and compare the differences of cell proliferation, apoptosis, and the expression levels of apoptosis signal-regulating kinase 1 (ASK1), c-Jun N-terminal kinase (JNK), matrix metalloproteinase-9 (MMP-9), and B-cell lymphoma-2 (Bcl-2) after ox-LDL induction and transfection of miR-9 mimic, miR-9 inhibitor and XIST expression vector, respectively. The results showed that lncRNA XIST overexpression vector was successfully constructed and transfected into cells, wh5ich can inhibit the expression level of miR-9. Compared with the normal control group, ox-LDL can inhibit cell proliferation, promote cell apoptosis, and increase the expression level of target protein. Moreover, transfection of XIST expression vector based on ox-LDL induction can significantly enhance the inhibition of cell proliferation, and promote cell apoptosis and the expression of target protein. Transfection of miR-9 mimic can improve the biological changes induced by ox-LDL. After co-transfection of miR-9 mimic and XIST expression vector based on ox-LDL induction, cell proliferation, apoptosis, and target protein expression level were not significantly different from those induced by ox-LDL alone. In summary, the increased expression level of miR-9 can inhibit the apoptosis of macrophages induced by ox-LDL. lncRNA XIST can positively regulate the apoptosis of macrophages induced by ox-LDL.

Long non-coding RNA XIST: a novel oncogene in multiple cancers

Long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) is an important lncRNA derived from the XIST gene in mammals. XIST is abnormally expressed in numerous tumors, in most of which XIST functions as an oncogene. XIST is involved in multiple aspects of carcinogenesis, including tumor onset, progression, and prognosis. In our review, we collected and analyzed the recent studies on the impact of XIST in human tumor development. The multilevel molecular functions of XIST in human tumors are comprehensively reviewed to clarify the pathologic mechanisms and to offer a novel direction for further study.

Long non-coding RNA XIST accelerates hepatic carcinoma progression by targeting the microRNA-320a/PIK3CA axis

The aim of the present study was to reveal the new molecular mechanism of long non-coding (lnc)RNA XIST in the development of hepatic carcinoma. A total of 69 patients with hepatic carcinoma were included. Hepatoma cell lines (SUN449), hepatoblastoma cell line (HepG2, Huh-6), liver cancer cell line (HepG2) and transformed human liver epithelial-2 cells (THLE-2) were used in the present study. A total 3 short hairpin RNA (sh)-lncRNA XIST sequences, overexpression vector (oe)-lncRNA XIST, microRNA (miR)-320a mimic, miR-320a inhibitor, PIK3CA inhibitor, and their corresponding controls were transfected in hepatic carcinoma cells. Reverse transcription-quantitative polymerase chain reaction was conducted to detect lncRNA-XIST, miR-320a and PIK3CA expression. Cell Counting Kit-8 assay and flow cytometry were undertaken to measure proliferation and apoptosis. Cell invasion and migration were detected by Transwell assays. Moreover, the binding of lncRNA XIST, PIK3CA and miR-320a were verified by luciferase reporter experiment and pull-down assay. Finally, a rescue assay was processed to confirm the effect of lncRNA-XIST, miR-320a and PIK3CA in the aforementioned processes. lncRNA XIST was highly expressed in hepatic carcinoma tissues and cells. The survival rate was significantly lower in the highly expressed lncRNA XIST group. shlncRNA XIST attenuated cell proliferation, invasion and migration, while increasing the apoptosis of hepatic carcinoma cells. The lncRNA XIST negatively targeted miR-320a, and miR-320a negatively regulated the expression of PIK3CA. The miR-320a mimic and PIK3CA inhibitor could recover the effect of oe-lncRNA in terms of the proliferation, invasion, migration and apoptosis of hepatic carcinoma cells. lncRNA XIST accelerates hepatic carcinoma progression by targeting the miR-320a/PIK3CA axis, which might provide the theoretical basis for the potential targeted therapy of hepatic carcinomas.

XIST: A Meaningful Long Noncoding RNA in NSCLC Process

BACKGROUND

A number of studies have proposed that lncRNA XIST plays a role in the development and chemosensitivity of NSCLC. Besides, XIST may become a potential therapeutic target for NSCLC patients. The aim of this review is to reveal the biological functions and exact mechanisms of XIST in NSCLC.

METHODS

In this review, relevant researches involving the relationship between XIST and NSCLC are collected through systematic retrieval of PubMed.

RESULTS

XIST is an oncogene in NSCLC and is abnormally upregulated in NSCLC tissues. Considerable evidence has shown that XIST plays a critical role in the proliferation, invasion, migration, apoptosis and chemosensitivity of NSCLC cells. XIST mainly functions as a ceRNA in the NSCLC process, while XIST also functions at transcriptional levels.

CONCLUSION

LncRNA XIST has the potential to become a novel biomolecular marker of NSCLC and a therapeutic target for NSCLC.

LncRNA XIST is involved in rheumatoid arthritis fibroblast-like synoviocytes by sponging miR-126-3p via the NF-κB pathway

The role and mechanism of lncRNA XIST (XIST) in the development of rheumatoid arthritis (RA) was explored in this study. RT-qPCRs were performed to detect the expression of XIST and miR-126-3p in synovial tissues and cells. Target gene prediction and luciferase gene reporter assay were used to validate downstream target genes of XIST. MTT assay, EdU staining and Annexin V/PI staining were performed to explore the effects of XIST and miR-126-3p on cell proliferation and apoptosis. Western blotting analysis was used to detect the expression of related proteins. We found that the expression levels of XIST in tissues and cells were significantly higher than that in normal tissues and cells. Down-regulation of XIST could inhibit cell proliferation rate and increase apoptosis rate. Luciferase gene reporter assay showed that miR-126-3p was a downstream target gene of XIST. Overexpression of miR-126-3p significantly inhibited RA-FLS cell proliferation and induced RA-FLS cell apoptosis. In addition, down-regulation of XIST could increase the ratio of caspase-3 and Bax/Bcl-2. In addition, overexpression of miR-126-3p could inhibit the NF-κB signalling pathway by reducing the expression levels of p-p65 and p-IκBα in RA-FLS cells. In conclusion, down-regulation of XIST can inhibit the proliferation of synovial fibroblasts by increasing the expression levels of miR-126-3p/NF-κB, thereby inhibiting the occurrence and development of RA.

X-Inactive-Specific Transcript: Review of Its Functions in the Carcinogenesis

X-inactive-specific transcript (XIST) is one of the firstly discovered long non-coding RNAs with prominent roles in the process of X inactivation. Moreover, this transcript contributes in the carcinogenic process in different tissues. In addition to interacting with chromatin modifying molecules, XIST can be served as a molecular sponge for miRNAs to modulate expression of miRNA targets. Most of the studies have indicated an oncogenic role for XIST. However, in prostate cancer, a single study has indicated a tumor suppressor role for this lncRNA. Similar result has been reported for XIST in oral squamous cell carcinoma. In hepatocellular carcinoma, breast cancer, ovarian cancer, osteosarcoma, and renal cell carcinoma, different studies have reported inconsistent results. In the present manuscript, we review function of XIST in the carcinogenesis.

Biological Function of Long Non-coding RNA (LncRNA) Xist

Long non-coding RNAs (lncRNAs) regulate gene expression in a variety of ways at epigenetic, chromatin remodeling, transcriptional, and translational levels. Accumulating evidence suggests that lncRNA X-inactive specific transcript (lncRNA Xist) serves as an important regulator of cell growth and development. Despites its original roles in X-chromosome dosage compensation, lncRNA Xist also participates in the development of tumor and other human diseases by functioning as a competing endogenous RNA (ceRNA). In this review, we comprehensively summarized recent progress in understanding the cellular functions of lncRNA Xist in mammalian cells and discussed current knowledge regarding the ceRNA network of lncRNA Xist in various diseases. Long non-coding RNAs (lncRNAs) are transcripts that are more than 200 nt in length and without an apparent protein-coding capacity (Furlan and Rougeulle, 2016; Maduro et al., 2016). These RNAs are believed to be transcribed by the approximately 98-99% non-coding regions of the human genome (Derrien et al., 2012; Fu, 2014; Montalbano et al., 2017; Slack and Chinnaiyan, 2019), as well as a large variety of genomic regions, such as exonic, tronic, and intergenic regions. Hence, lncRNAs are also divided into eight categories: Intergenic lncRNAs, Intronic lncRNAs, Enhancer lncRNAs, Promoter lncRNAs, Natural antisense/sense lncRNAs, Small nucleolar RNA-ended lncRNAs (sno-lncRNAs), Bidirectional lncRNAs, and non-poly(A) lncRNAs (Ma et al., 2013; Devaux et al., 2015; St Laurent et al., 2015; Chen, 2016; Quinn and Chang, 2016; Richard and Eichhorn, 2018; Connerty et al., 2020). A range of evidence has suggested that lncRNAs function as key regulators in crucial cellular functions, including proliferation, differentiation, apoptosis, migration, and invasion, by regulating the expression level of target genes via epigenomic, transcriptional, or post-transcriptional approaches (Cao et al., 2018). Moreover, lncRNAs detected in body fluids were also believed to serve as potential biomarkers for the diagnosis, prognosis, and monitoring of disease progression, and act as novel and potential drug targets for therapeutic exploitation in human disease (Jiang W. et al., 2018; Zhou et al., 2019a). Long non-coding RNA X-inactive specific transcript (lncRNA Xist) are a set of 15,000-20,000 nt sequences localized in the X chromosome inactivation center (XIC) of chromosome Xq13.2 (Brown et al., 1992; Debrand et al., 1998; Kay, 1998; Lee et al., 2013; da Rocha and Heard, 2017; Yang Z. et al., 2018; Brockdorff, 2019). Previous studies have indicated that lncRNA Xist regulate X chromosome inactivation (XCI), resulting in the inheritable silencing of one of the X-chromosomes during female cell development. Also, it serves a vital regulatory function in the whole spectrum of human disease (notably cancer) and can be used as a novel diagnostic and prognostic biomarker and as a potential therapeutic target for human disease in the clinic (Liu et al., 2018b; Deng et al., 2019; Dinescu et al., 2019; Mutzel and Schulz, 2020; Patrat et al., 2020; Wang et al., 2020a). In particular, lncRNA Xist have been demonstrated to be involved in the development of multiple types of tumors including brain tumor, Leukemia, lung cancer, breast cancer, and liver cancer, with the prominent examples outlined in Table 1. It was also believed that lncRNA Xist (Chaligne and Heard, 2014; Yang Z. et al., 2018) contributed to other diseases, such as pulmonary fibrosis, inflammation, neuropathic pain, cardiomyocyte hypertrophy, and osteoarthritis chondrocytes, and more specific details can be found in Table 2. This review summarizes the current knowledge on the regulatory mechanisms of lncRNA Xist on both chromosome dosage compensation and pathogenesis (especially cancer) processes, with a focus on the regulatory network of lncRNA Xist in human disease.

Clinical impact of LncRNA XIST and LncRNA NEAT1 for diagnosis of high-risk group breast cancer patients

Long noncoding RNAs (lncRNAs) are evolving as contributing biomarkers for many diseases. Among these lncRNAs, X inactive-specific transcript (XIST), and nuclear paraspeckle assembly transcript 1 (NEAT1) were studied as undesirable upregulated nucleic acid markers for unfavorable prognosis of cancer. The authors aimed to investigate their role as diagnostic markers for breast cancer (BC) patients with high-risk factors. Serum samples were obtained from BC patients (n = 121), patients with benign breast lesions (n = 35), and healthy volunteers (n = 22). Assessment of lncRNA XIST, and lncRNA NEAT1 expression was performed using real time PCR. Expression levels of the investigated lncRNAs were significantly higher in BC patients as compared to the other groups. Both lncRNAs were significantly correlated with BC laterality, lymph node involvement, and clinical stages. LncRNA NEAT1 reported a significant aberrant expression with pathological types, histological grading and, hormonal status. The sensitivity of lncRNA NEAT1 was superior for detection of BC with high risk-factors as compared to lncRNA XIST. In conclusion, the detection of lncRNAs in body fluids has demonstrated a significant importance for detecting BC patients with high-risk factors, and was related to hormonal receptors, thus may be used for determining the direction of treatment strategy.

Identification of Primary and Metastatic Lung Cancer-Related lncRNAs and Potential Targeted Drugs Based on ceRNA Network

Lung cancer metastasis is the leading cause of poor prognosis and death for patients. Long noncoding RNAs (lncRNAs) have been validated the close correlation with lung cancer metastasis, but few comprehensive analyses have reported the specific association between lncRNA and cancer metastasis, especially via both competing endogenous RNA (ceRNA) regulatory relationships and functional regulatory networks. Here, we constructed primary and metastatic ceRNA networks, identified 12 and 3 candidate lncRNAs for lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) respectively and excavated some drugs that might have potential therapeutic effects on lung cancer progression. In summary, this study systematically analyzed the competitive relationships and regulatory mechanism of the repeatedly dysregulated lncRNAs in lung cancer carcinogenesis and metastasis, and provided a new idea for screening potential therapeutic drugs for lung cancer.

microRNA-140: A miRNA with diverse roles in human diseases

MicroRNA-140 (miR-140) has been shown to be associated with the pathogenesis of a wide range of pathologies including osteoarthritis, osteoporosis, renal fibrosis, ischemic conditions, and most importantly neoplasia. This miRNA has been shown to be down-regulated in a diversity of cancers namely breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. miR-140 has a lot of immune-related targets. Moreover, several miR-140 targets regulate cell proliferation, cell cycle transition, and apoptosis. This miRNA has been shown to be sponged by a number of lncRNAs and circ-RNAs. miR-140 has essential roles in the determination of the sensitivity of neoplastic cells to chemotherapeutic agents such as temozolomide, doxorubicin, and cisplatin. Besides, expression quantities of miR-140 in cancer tissues can be used for the prediction of clinical outcomes of patients with neoplasia. In the present paper, we describe the impact of miR-140 in neoplastic and non-neoplastic disorders.

TUG1 promotes retinoblastoma progression by sponging miR-516b-5p to upregulate H6PD expression

Background

Retinoblastoma (RB), depicted as an aggressive eye cancer, mainly occurs in infancy and childhood and is followed by high mortality and poor prognosis. Increasing evidence has revealed that long noncoding RNA taurine upregulated gene 1 (TUG1) is closely linked to the progression of diverse cancers. Nonetheless, the specific function and molecular regulatory mechanism of TUG1 in RB still need to be explored.

Methods

To explore the specific role of TUG1 in RB. TUG1 expression was detected by real-time quantitative polymerase chain reaction (RT-qPCR). Cell counting kit-8 (CCK-8), colony formation, 5-ethynyl-2’-deoxyuridine (EdU), caspase-3, terminal-deoxynucleotidyl transferase mediated nick end labeling (TUNEL) and western blot assays were utilized to study the role of TUG1 in RB. The binding relation between miR-516b-5p and TUG1 or hexose-6-phosphate dehydrogenase/glucose 1-dehydrogenase (H6PD) was analyzed by luciferase reporter and RNA immunoprecipitation (RIP) assays.

Results

The expression of TUG1 was upregulated in RB cells. TUG1 knockdown repressed proliferation ability and promoted apoptosis ability of RB cells. Moreover, TUG1 could bind with miR-516b-5p, which targeted H6PD in RB. In addition, the expression of H6PD was negatively and positively regulated by miR-516b-5p and TUG1 in RB, respectively. Finally, H6PD overexpression could partially offset the effects of TUG1 deficiency on cell proliferation and apoptosis.

Conclusions

TUG1 promoted the development of RB by sponging miR-516b-5p to upregulate H6PD expression, which might provide a new thought for researching RB-related molecular mechanism.

Effects of LncRNA HCP5/miR-214-3p/MAPK1 Molecular Network on Renal Cell Carcinoma Cells

Background

Recent researches have shown that long non-coding RNA (LncRNA) is often disordered and acts in many carcinomas. Clear cell renal cell carcinoma (ccRCC) is the main reason for carcinoma-related deaths, which are mainly caused by the metastasis. HCP5 is a newly discovered LcnRNA. Early studies have found that HCP5 acts in neoplasm metastasis, but the mechanism of HCP5 in ccRCC is still unclear.

Methods

The expression of HCP5 in human renal cell carcinoma (RCC) was detected by real-time quantitative PCR. The biological effect of LncRNAs in proliferation, migration, invasion and metastasis of RCC cells was explored by gain-of-function and loss-of-function tests. The molecular mechanism of LncRNAs was explored by RNA immunoprecipitation and Western blot.

Results

qRT-PCR revealed that HCP5 was enhanced in neoplasm tissues of ccRCC patients and correlated with the metastatic characteristics of RCC. Over-expression of HCP5 promoted the proliferation, migration and invasion of renal carcinoma cells. The deletion of HCP5 inhibited the proliferation, migration and invasion of RCC in vitro and the metastasis of RCC in vivo. Mechanically, HCP5 inhibited the growth and metastasis of ccRCC cells by regulating miR-214-3p/MAPK1 axis.

Conclusion

HCP5, as a key LncRNA, can promote ccRCC metastasis by regulating miR-214-3p/MAPK1 axis and may be a biomarker and be helpful for judging the prognosis of ccRCC.

Circular RNA hsa_circ_0008003 facilitates tumorigenesis and development of non-small cell lung carcinoma via modulating miR-488/ZNF281 axis

As one of the most aggressive malignancies, non‐small cell lung carcinoma (NSCLC) has high risks of death. It has been demonstrated that circRNAs accelerate NSCLC progression, but the underlying molecular mechanisms of circRNAs in NSCLC were still obscure. In the first place, the circRNA microarray of NSCLC was investigated in this study, and hsa_circ_0008003 (circ‐0008003) was chosen as the research object. Then, it was unveiled that the expression of circ‐0008003 examined via qRT‐PCR was elevated in tumour tissues relative to the non‐tumour tissues, which was associated with TNM stage and lymphatic metastasis in NSCLC. Additionally, the prognosis of NSCLC patients with high circ‐0008003 level was poor. Besides, circ‐0008003 silencing dampened the invasion and proliferation of NSCLC cells. Next, according to the mechanistic studies, circ‐0008003 functioned as a ceRNA of ZNF281 in NSCLC by acting as the endogenous sponge for miR‐488, which was proved to be a tumour suppressor in NSCLC. Additionally, ZNF281 overexpression and miR‐488 suppression recovered the influences of repressed circ‐0008003 on NSCLC cellular processes. It was validated in this research that circ‐0008003 triggered tumour formation in NSCLC, which was adjusted via miR‐488/ZNF281 axis, casting a novel light on the resultful target for treating NSCLC and predicting the prognosis.

Downregulated microRNA-140-5p expression regulates apoptosis, migration and invasion of lung cancer cells by targeting zinc finger protein 800

Despite advances in the diagnosis and treatment in recent years, lung cancer is still one of the primary causes of cancer-associated morbidity and mortality in globally. Abnormally expressed microRNAs (miRNAs/miRs) in tumor tissues serve vital roles in the pathological mechanism of tumors and have become prospective biomarkers for cancer diagnosis. The present study aimed to investigate the effects of the miR-140-5p/zinc finger protein 800 (ZNF800) axis in lung carcinoma, and determine its potential underlying molecular mechanisms. The degree of cell proliferation was assessed via the MTT assay, while the migratory and invasive abilities of lung cancer cells were determined via the Transwell and Matrigel assays. The expression levels of miR-140-5p and ZNF800 were detected via reverse transcription-quantitative PCR and western blot analyses. The results demonstrated that miR-140-5p expression was notably higher in normal human bronchial epithelial cells compared with the respective lung cancer cell lines, H292, PC-9, CL1-5 and H460. Furthermore, miR-140-5p expression increased in the lung cancer cells compared with the control cells following transfection with miR-140-5p mimic. Overexpressing miR-140-5p significantly suppressed the proliferative, invasive and migratory abilities of H460 and PC-9 cells, and stimulated cell apoptosis by upregulating the expression of cleaved-caspase-3. Notably, these effects were reversed following transfection with miR-140-5p inhibitor. miR-140-5p was predicted as a negative regulator of ZNF800, and ZNF800 knockdown significantly suppressed the proliferative and metastatic abilities of lung adenocarcinoma (LUAD) cells, which was comparable to the effects of miR-140-5p mimic. Taken together, these results suggest that miR-140-5p may block the malignant phenotype of LUAD by negatively regulating ZNF800 expression. Thus, the miR-140-5p/ZNF800 axis may be used as an alternative therapeutic target for lung carcinoma in general, and LUAD in particular.

The roles of long noncoding RNAs in breast cancer metastasis

Breast cancer is the most significant threat to female health. Breast cancer metastasis is the major cause of mortality in breast cancer patients. To fully unravel the molecular mechanisms that underlie the breast cancer cell metastasis is critical for developing strategies to improve survival and prognosis in breast cancer patients. Recent studies have revealed that the long noncoding RNAs (lncRNAs) are involved in breast cancer metastasis through a variety of molecule mechanisms, though the precise functional details of these lncRNAs are yet to be clarified. In the present review, we focus on the functions of lncRNAs in breast cancer invasion and metastasis, with particular emphasis on the functional properties, the regulatory factors, the therapeutic promise, as well as the future challenges in studying these lncRNA.

Carboplatin Inhibits the Progression of Retinoblastoma Through IncRNA XIST/miR-200a-3p/NRP1 Axis

Objective

This study was set out to explore the expression and related mechanism of XIST and miR-200a-3p in retinoblastoma (Rb).

Patients and Methods

Fifty-four children with Rb who came to our hospital for surgery from January 2018 to September 2019 were collected. In addition, Rb cells and human retinal epithelial cells were purchased. XIST-siRNA (si-XIST), XIST-shRNA (sh-XIST), empty vector plasmid (siRNA-NC), miR-200a-3p-mimics and miR −200a-3p-inhibition were transfected into Y79 cells. The expression of XIST and miR-200a-3p in the samples were determined by qRT-PCR. β-catenin, cyclin B1, cyclin D1, Bax, Caspase-3, N-cadherin, vimentin, Snail, E-Cadherin and ZO-1 protein levels were measured by WB. MTT, Transwell and flow cytometry were utilized to detect cell proliferation, invasion, and apoptosis, respectively.

Results

XIST was highly expressed while miR-200a-3p was lowly expressed in patients’ tissues, and the AUC of both was over 0.8. XIST and miR-200a-3p was related to differentiation degree in Rb patients. Y79 cells were selected for transfection. Compared with the siRNA-NC group, XIST was significantly reduced in the siRNA-XIST group, and it was significantly increased in the shRNA-XIST group (P<0.01). The proliferation capacity of siRNA-XIST group was decreased, while that of shRNA-XIST group was up-regulated. The apoptosis rate of siRNA-XIST group was significantly up-regulated, while that of shRNA-XIST group was decreased (P<0.001). The invasive capacity of siRNA-XIST group was decreased, while that of shRNA-XIST group was up-regulated (P<0.001). Silencing XIST and over-expressed miR-200a-3p could inhibit cell epithelial–mesenchymal transition (EMT), proliferation, invasion, and promote apoptosis. WB detection showed that Carboplatin + LncRNA XIST intervention group could more significantly inhibit β-catenin, cyclin B1, cyclin D1, N-cadherin, vimentin, Snail protein, and promote the up-regulation of Bax, Caspase-3, E-Cadherin and ZO-1 expression.

Conclusion

Inhibition of XIST expression can up-regulate miR-200a-3p-mediated PI3K-Akt/MAPK-ERK signaling pathway and affect cell EMT, proliferation, invasion, and apoptosis, which is expected to be a potential therapeutic target for Rb.

Long noncoding RNA XIST knockdown suppresses the growth of colorectal cancer cells via regulating microRNA-338-3p/PAX5 axis

BACKGROUND

Colorectal cancer is one of the most common human cancers worldwide. Long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) have been reported as the regulators in cancers. The purpose of this study was to reveal the functional mechanisms of lncRNA x inactive specific transcript (XIST) and miR-338-3p in colorectal cancer cells.

METHODS

The transcription level and protein level of genes were assessed by quantitative real-time PCR (qRT-PCR) and western blot assay, respectively. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay and flow cytometry analysis were used to determine cell proliferation ability and apoptosis rate, respectively. In addition, cell migratory ability and invasive ability were measured using transwell assay. Besides, the interaction between miR-338-3p and XIST or paired box 5 (PAX5) was predicted by starBase or TargetScan and then verified by the dual-luciferase reporter assay.

RESULTS

XIST and PAX5 expression were increased, and miR-338-3p expression was decreased in colorectal cancer tissues and cells. XIST knockdown significantly repressed cell proliferation, migration and invasion, and accelerated apoptosis in colorectal cancer cells. Interestingly, XIST directly downregulated miR-338-3p expression to increase PAX5 level. As expected, XIST knockdown inhibited colorectal cancer cell growth by modulating miR-338-3p expression. Furthermore, miR-338-3p suppressed cell growth via downregulation of PAX5 level in colorectal cancer cells.

CONCLUSION

Our results demonstrated that the downregulation of XIST inhibited cell proliferation, migration and invasion, and induced apoptosis through modulating miR-338-3p/PAX5 axis in colorectal cancer cells, providing potential target for the prevention and treatment of colorectal cancer.

Identification of differentially expressed long non-coding RNAs associated with dilated cardiomyopathy using integrated bioinformatics approaches

The aim of this study was to identify novel long non-coding RNA (lncRNA) biomarkers associated with dilated cardiomyopathy (DCM) and reveal the potential molecular mechanisms of DCM development using bioinformatics approaches. The array data of GSE5406, including 108 DCM samples and 16 non-failing control samples, were obtained from the Gene Expression Omnibus database. The differentially expressed lncRNAs were identified using limma package in R. Pearson's correlation analyses were performed between the differentially expressed lncRNAs and protein-coding genes based on their expression levels. Pathway enrichment of these lncRNAs was conducted based on the significantly co-expressed genes. From the receiver operating characteristic (ROC) curve, the area under the ROC curve (AUC) value was obtained and used for evaluating discriminatory ability. IDI2-AS1 and XIST were differentially expressed in DCM patients. A total of 510 co-expressed genes were identified. The enriched functions and pathways of the co-expressed genes mainly included NADH dehydrogenase activity, cardiac muscle contraction, and oxidative phosphorylation. The ROC curve analysis indicated that the two lncRNAs have favorable diagnostic values in DCM. The AUC values of XIST, IDI2-AS1, and the combination of XIST and IDI2-AS1 were 0.733 (95% CI: 0.646-0.809), 0.796 (95% CI: 0.715-0.863), and 0.823 (95% CI: 0.745-0.886), respectively. This study identified IDI2-AS1 and XIST lncRNAs and related pathways involved in the pathogenesis of DCM, thus providing potential diagnostic and therapeutic targets for DCM.

Knockdown of lncRNA XIST Suppresses Cell Tumorigenicity in Human Non-Small Cell Lung Cancer by Regulating miR-142-5p/PAX6 Axis

Background

Long noncoding RNA X inactivate-specific transcript (lncRNA XIST) has been identified to contribute to the development and progression of non-small cell lung cancer (NSCLC). Thus, it is important to explore more specific functions and molecular mechanisms of XIST in NSCLC tumorigenesis.

Materials and Methods

The expression of XIST, microRNA (miR)-142-5p and paired box 6 (PAX6) was measured using quantitative real-time polymerase chain reaction or Western blot, respectively. Cell proliferation was analyzed using cell counting kit-8 (CCK-8) assay. Flow cytometry was utilized to measure apoptotic cells. Cell migration and invasion were determined by Transwell assay. The interaction between miR-142-5p and XIST or PAX6 was confirmed by the dual-luciferase reporter assay and RNA immunoprecipitation assay. In vivo experiments were performed through the murine xenograft model.

Results

XIST was elevated in NSCLC, and XIST knockdown suppressed cell proliferation, migration, invasion and induced apoptosis in vitro as well as repressed tumor growth in vivo. MiR-142-5p was a target of XIST, and silencing miR-142-5p reversed the anti-tumor functions mediated by XIST knockdown in NSCLC cells. PAX6 was confirmed to be a target of miR-142-5p, and the inhibitory effects caused by miR-142-5p restoration in NSCLC cell malignant phenotypes were attenuated by PAX6 overexpression. Besides that, XIST could indirectly regulate PAX6 expression by sponging miR-142-5p in vivo and in vitro.

Conclusion

XIST suppresses cell tumorigenicity in human NSCLC by regulating miR-142-5p/PAX6 axis, which indicates a novel insight into the pathogenesis of NSCLC and lays a foundation for the molecular therapy of NSCLC.

Long Noncoding RNA XIST Contributes to Cervical Cancer Development Through Targeting miR-889-3p/SIX1 Axis

Background: Cervical cancer (CC) is one of the most common cancers among women in the world. Long noncoding RNAs and microRNAs were identified as important regulators in many physiological processes. The objective of this study was to illuminate the mechanism of X-inactive-specific transcript (XIST)/miR-889-3p/Sine oculis homeobox 1 (SIX1) axis in CC. Methods: The expression levels of XIST, miR-889-3p, and SIX1 were detected by quantitative real-time polymerase chain reaction. Cell proliferation was assessed by cell counting Kit 8 assay. Cell migration and invasion were evaluated by transwell assay. Cell apoptosis was detected by flow cytometry assay. Murine model was established using transfected Me180 cell. The interaction among XIST, miR-889-3p, and SIX1 was tested by dual-luciferase reporter and RNA immunoprecipitation assays. Protein level of SIX1 was measured by Western blot. Results: XIST was highly expressed in CC tissues and cells. Silenced XIST inhibited proliferation, migration, and invasion and induced apoptosis. Moreover, XIST silencing blocked tumor growth in vivo. XIST directly bound to miR-889-3p, and XIST promoted proliferation, migration, and invasion and hindered apoptosis by suppressing miR-889-3p expression. MiR-889-3p targeted SIX1 and negatively regulated SIX1 expression. Furthermore, miR-889-3p had a low expression and SIX1 had a high expression in CC tissues and cells. XIST knockdown reduced SIX1 level by targeting miR-889-3p. In addition, miR-889-3p inhibition abolished the effects of SIX silencing on proliferation, migration, invasion, and apoptosis. Conclusion: XIST knockdown restrained cell proliferation, migration, and invasion and promoted apoptosis by regulating miR-889-3p/SIX1 axis.

Non-coding RNA profile in lung cancer

Lung cancer is the most frequently diagnosed malignancy and the leading source of cancer-associated mortality. This kind of cancer has heterogeneous nature and is divided into two broad classes of small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). In addition to aberrant expression of several signaling pathways and oncogenes, lung cancer is associated with dysregulation of expression of non-coding RNAs including both long non-coding RNAs (lncRNAs) and miRNAs. These aberrantly expressed transcripts are putative therapeutic targets and diagnostic/ prognostic markers. Integrative assessment of expression of lncRNAs, miRNAs and mRNAs has led to construction of competing endogenous RNA networks in which several lncRNAs act as molecular sponges to inhibit regulatory function of miRNAs on mRNAs. Notably, some of these networks seem to have subtype-specific functions in lung cancer. In this review, we summarize recent findings about the importance of these networks in the pathogenesis of lung cancer and provide a list of onco-miRNAs, tumor suppressor miRNAs, oncogenic lncRNAs and tumor suppressor lncRNAs based on their roles in the carcinogenic process in lung cancer.

Long non‑coding RNA CCAT1 enhances human non‑small cell lung cancer growth through downregulation of microRNA‑218

Long non-coding RNAs (lncRNAs) have critical functions in non-small cell lung cancer (NSCLC) growth. In the present study, we showed that lncRNA-CCAT1 was upregulated in NSCLC tissues. High expression of lncRNA-CCAT1 was related to tumor growth and reduced survival rate. We used short hairpin RNAs (shRNAs) to inhibit the expression of lncRNA-CCAT1 in NSCLC cells. In vitro and in vivo results demonstrated that lncRNA-CCAT1 knockdown suppressed tumor proliferation and induced apoptosis. Furthermore, microRNA-218 (miR-218) was confirmed as an effective target of lncRNA-CCAT1 in NSCLC. B lymphoma Mo-MLV insertion region 1 homolog (BMI-1), which served as a downstream target of miR-218, was also inhibited by lncRNA-CCAT1 knockdown. In conclusion, the present study indicated that upregulation of lncRNA-CCAT1 in NSCLC is associated with tumor malignant potential. lncRNA-CCAT1 enhances tumor growth in NSCLC by directly inhibiting miR-218 and indirectly increasing BMI-1 expression.

lncRNA HOXB-AS3 exacerbates proliferation, migration, and invasion of lung cancer via activating the PI3K-AKT pathway

Lung cancer remains the leading cause of cancer-related death all over the world. In spite of the great advances made in surgery and chemotherapy, the prognosis of lung cancer patients is poor. A substantial fraction of long noncoding RNAs (lncRNAs) can regulate various cancers. A recent study has reported that lncRNA HOXB-AS3 plays a critical role in cancers. However, its biological function remains unclear in lung cancer progression. In the current research, we found HOXB-AS3 was obviously elevated in NSCLC tissues and cells. Functional assays showed that inhibition of HOXB-AS3 was able to repress A549 and H1975 cell proliferation, cell colony formation ability and meanwhile, triggered cell apoptosis. Furthermore, the lung cancer cell cycle was mostly blocked in the G1 phase whereas the cell ratio in the S phase was reduced. Also, A549 and H1975 cell migration and invasion capacity were significantly repressed by the loss of HOXB-AS3. The PI3K/AKT pathway has been implicated in the carcinogenesis of multiple cancers. Here, we displayed that inhibition of HOXB-AS3 suppressed lung cancer cell progression via inactivating the PI3K/AKT pathway. Subsequently, in vivo experiments were utilized in our study and it was demonstrated that HOXB-AS3 contributed to lung cancer tumor growth via modulating the PI3K/AKT pathway. Overall, we implied that HOXB-AS3 might provide a new perspective for lung cancer treatment via targeting PI3K/AKT.

Long noncoding RNA LINC01278 favors the progression of osteosarcoma via modulating miR-133a-3p/PTHR1 signaling

As one of the most aggressive malignancies, osteosarcoma has high risks of death. Although long noncoding RNAs (lncRNAs) may promote the osteosarcoma progression as verified, the potential molecular mechanism of lncRNAs in osteosarcoma remains unknown. Herein, we analyzed lncRNA microarray of osteosarcoma and selected LINC01278 as the study object. Then, we found that the expression of LINC01278 tested by quantitative reverse-transcription polymerase chain reaction was enhanced in tumor tissues compared with the para-carcinoma tissues and related to clinical stage, distant metastasis in osteosarcoma. In addition, the clinical outcomes were poor in osteosarcoma patients with high LINC01278 level. Moreover, LINC01278 promoted proliferation and restrained apoptosis in osteosarcoma cells. Afterward, mechanistic studies turned out that LINC01278 was a competing endogenous RNA of parathyroid hormone type 1 receptor (PTHR1) in osteosarcoma by sponging miR-133a-3p, which was considered as a tumor inhibitor in osteosarcoma. Furthermore, PTHR1 downregulation restored the impacts of inhibited miR-133a-3p on the processes in osteosarcoma cells. Our findings clarified that the carcinogenic effect of LINC01278 in osteosarcoma was mediated through miR-133a-3p/PTHR1 signaling, creating a novel insight into good targets for the therapy and prognosis of osteosarcoma.

Long non-coding RNA X-inactive specific transcript silencing ameliorates primary graft dysfunction following lung transplantation through microRNA-21-dependent mechanism

Background

Primary graft dysfunction (PGD) is a known acute lung injury (ALI) and a major cause of fatality post-lung transplantation. Though some long non-coding RNAs (lncRNAs) have been studied in ALI through regulation of microRNAs (miRNAs), their effects on PGD remain undefined. The present study aims to explore the underlying mechanism of lncRNA X-inactive specific transcript (XIST) in PGD after lung transplantation.

Methods

Initially, the expression of miR-21, IL-12A and XIST was determined by RT-qPCR and western blot analysis. The dual luciferase reporter assay, RNA pull-down and RIP assay were performed to identify the targeting relationship between miR-21 and IL-12A and the binding relationship between miR-21 and XIST. Loss- and gain-of-function investigations were conducted in rats treated with prolonged cold ischemia and polymorphonuclear neutrophils (PMNs).

Findings

miR-21 was decreased, whilst XIST and IL-12A were increased in the bronchoalveolar lavage fluid of PGD patients after lung transplantation. Enhanced miR-21 expression in rats and PMNs resulted in downregulated expression of pro-inflammatory factors and chemokines, and enhanced the apoptosis of PMNs. XIST was found to upregulate IL-12A expression in a miR-21-dependent manner. Additionally, XIST silencing enhanced the apoptosis of PMNs and inhibited the neutrophil extracellular trap (NET) formation through upregulation of miR-21 but downregulation of IL-12A in vivo.

Interpretation

In summary, lncRNA XIST upregulates IL-12A by binding to miR-21, thereby inducing NET formation and accelerating PGD after lung transplantation. This suggests that inhibition of XIST and NET may be beneficial for the treatment of PGD.

LncRNA-ATB Promotes Lung Squamous Carcinoma Cell Proliferation, Migration, and Invasion by Targeting microRNA-590-5p/NF90 Axis

Lung cancer with highest morbidity and mortality seriously threatens human health worldwide. Long noncoding RNAs (lncRNAs) exert important biological functions by acting as microRNA, which is implicated in tumorigenesis and cancer development. Previous work has reported that lncRNA-ATB expression was significantly upregulated in lung adenocarcinoma tissues and promoted tumor progression; however, the mechanisms of lncRNA-ATB in lung squamous carcinoma (LSC) are still fairly elusive. In our study, lncRNA-ATB expression also markedly increases in LSC tissues and cell lines in comparison to the adjacent normal tissues and normal lung epithelial cells, respectively. Functional experiments indicate that lncRNA-ATB overexpression improves the proliferative, migratory, and invasive capabilities of normal lung epithelial cells compared with control group. Furthermore, the migratory and invasive abilities are strikingly inhibited in lncRNA-ATB silenced LSC cells. Mechanistically, lncRNA-ATB directly binds to microRNA-590-5p and downregulates microRNA-590-5p level, leading to the upregulation of NF-90 expression. In addition, lncRNA-ATB overexpression promotes the epithelial-mesenchymal transition process, where lncRNA-ATB overexpression facilitates the expression of mesenchymal phenotype related molecules N-cadherin and vimentin, while restrains the expression of epithelial phenotype related proteins E-cadherin and CK-19, compared to the control. Conversely, microRNA-590-5p mimics can reverse the results caused by lncRNA-ATB overexpression. Taken together, our initial data suggest that lncRNA-ATB overexpression may promote the progression of LSC by modulating the microRNA-590-5p/NF-90 axis.

lncRNA XIST promotes glioma proliferation and metastasis through miR-133a/SOX4

Glioma is the most common malignant brain tumour in adults, and the aetiology and mechanism of this tumour remain largely unknown. Previous studies have demonstrated that the long non-coding RNA X-inactive specific transcript (XIST) is upregulated in many cancers, and a high expression level of XIST is associated with poor clinical outcome. In the present study, the expression and function of XIST were investigated in the glioma cell line U251. XIST and microRNA (miR)-133a levels in glioma cell lines were detected by reverse transcription-quantitative polymerase chain reaction. Small hairpin RNA XIST (sh-XIST) and mimics/inhibitor of miR-133a were transfected in glioma cell lines and cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) were examined. Luciferase assays were used to verify the associations among XIST, miR-133a and SRY-box (SOX)4. When XIST was knocked down, the proliferation, metastasis and EMT of glioma cells decreased. Notably, downstream genes of SOX4 were also upregulated or downregulated upon sh-XIST treatment. Overexpression of miR-133a inhibited glioma proliferation, metastasis and EMT via reducing the expression of SOX4; in contrast, knockdown of miR-133a exhibited the opposite effect, which revealed that miR-133a negatively regulates glioma progression. Furthermore, using luciferase assays, it was demonstrated that XIST and SOX4 could bind miR-133a in the predicted binding site; XIST competed with SOX4 for miR-133a binding. In conclusion, a XIST/miR-133a/SOX4 axis and a mechanism of XIST glioma in promoting cell proliferation and metastasis were revealed. These findings revealed that XIST has an oncogenic role in the tumourigenesis of glioma and may serve as a potential therapeutic target for glioma.

Long non-coding XIST raises methylation of TIMP-3 promoter to regulate collagen degradation in osteoarthritic chondrocytes after tibial plateau fracture

Background

Hypermethylation of gene promoters has been regarded as an epigenetic regulator for gene inactivation in the development of several diseases. In the current study, we aimed to explore how long noncoding RNA X-inactive specific transcript (lncRNA XIST) function in collagen degradation in chondrocytes of osteoarthritis (OA) after tibial plateau fracture by regulating tissue inhibitor of metalloproteinase-3 (TIMP-3) promoter methylation.

Methods

In silico analysis was used to screen differentially expressed lncRNAs in cartilage tissues of OA. Chondrocytes were then successfully isolated from normal and OA cartilage tissues and identified, with the expressions of lncRNA XIST and TIMP-3 examined. The methylation levels of TIMP-3 promoter were determined by MS-PCR. The binding of lncRNA XIST to DNA methyltransferase and the binding of TIMP-3 promoter to DNA methyltransferase were determined by a series of experiments, including RIP, RNA pull-down, and ChIP assays.

Results

The differentially expressed lncRNA XIST was determined in OA. In addition, cartilage tissues of OA showed upregulation of lncRNA XIST and downregulation of TIMP-3. LncRNA XIST was primarily localized in the nucleus and was capable of binding to the promoter of TIMP-3. The silencing of lncRNA XIST decreased the methylation levels of TIMP-3 promoter and increased the expressions of TIMP-3, which consequently inhibited collagen degradation in OA chondrocytes. Furthermore, TIMP-3 over-expression reversed the effect of lncRNA XIST on collagen degradation in OA chondrocytes.

Conclusion

Collectively, lncRNA XIST raises collagen degradation in OA chondrocytes after tibial plateau fracture by accelerating the methylation of TIMP-3 promoter by recruiting DNA methyltransferase.

Noncoding RNAs and Liquid Biopsy in Lung Cancer: A Literature Review

Lung cancer represents a genetically heterogeneous disease with low survival rates. Recent data have evidenced key roles of noncoding RNAs in lung cancer initiation and progression. These functional RNA molecules that can act as both oncogenes and tumor suppressors may become future biomarkers and more efficient therapeutic targets. In the precision medicine era, circulating nucleic acids have the potential to reshape the management and prognosis of cancer patients. Detecting genomic alterations and level variations of circulating nucleic acids in liquid biopsy samples represents a noninvasive method for portraying tumor burden. Research is currently trying to validate the potential role of liquid biopsy in lung cancer screening, prognosis, monitoring of disease progression, and treatment response. However, this method requires complex detection assays, and implementation of plasma genotyping in clinical practice continues to be hindered by discrepancies that arise when compared to tissue genotyping. Understanding the genomic landscape of lung cancer is essential in order to provide useful and innovative research in the age of patient-tailored therapy. In this landscape, the noncoding RNAs play a crucial role due to their target genes that dramatically influence the tumor microenvironment and the response to therapy. This article addresses present and future possible roles of liquid biopsy in lung cancer. It also discusses how the complex role of noncoding RNAs in lung tumorigenesis could influence the management of this pathology.

Silencing of long noncoding RNA XIST attenuated Alzheimer's disease-related BACE1 alteration through miR-124

Alzheimer's disease (AD) is a chronic progressive neurodegenerative disorder. However, its pathogenetic mechanism is still poorly understood. An increasing number of studies have evidenced the important role of long noncoding RNAs (lncRNAs) in AD. The aim of the current study was to investigate the effect and molecular mechanism of the lncRNA X-inactive specific transcript (XIST) in AD. Bilateral common carotid artery occlusion (2VO) was used to induce an AD model in mice. Hydrogen peroxide (H₂ O₂ ) was used to induce an AD model in N2a cells. The lncRNA XIST, miR-124, and BACE1 messenger RNA expression levels were detected by a real-time polymerase chain reaction. The BACE1 protein expression level was detected by western blot and immunofluorescence assay. The Aβ_1-42 expression level was detected using an enzyme-linked immunosorbent assay kit. The expression level of lncRNA XIST was significantly upregulated in AD models, both in vivo and in vitro. Silencing of lncRNA XIST negatively regulated miR-124 and positively regulated BACE1 expression in N2a cells, which is attenuated by cotransfection of anti-miR-124 oligodeoxyribonucleotide (AMO-124). Silencing of lncRNA XIST reversed the effect of H₂ O₂ on miR-124, BACE1, and Aβ_1-42 expression in N2a cells, which was reversed by cotransfection of AMO-124. Silencing of lncRNA XIST attenuated AD-related BACE1 alteration through miR-124. LncRNA XIST may be a new potential target for the treatment of AD.

Long Non-Coding RNA: Dual Effects on Breast Cancer Metastasis and Clinical Applications

As a highly heterogeneous malignancy, breast cancer (BC) has become the most significant threat to female health. Distant metastasis and therapy resistance of BC are responsible for most of the cases of mortality and recurrence. Distant metastasis relies on an array of processes, such as cell proliferation, epithelial-to-mesenchymal transition (EMT), mesenchymal-to-epithelial transition (MET), and angiogenesis. Long non-coding RNA (lncRNA) refers to a class of non-coding RNA with a length of over 200 nucleotides. Currently, a rising number of studies have managed to investigate the association between BC and lncRNA. In this study, we summarized how lncRNA has dual effects in BC metastasis by regulating invasion, migration, and distant metastasis of BC cells. We also emphasize that lncRNA has crucial regulatory effects in the stemness and angiogenesis of BC. Clinically, some lncRNAs can regulate chemotherapy sensitivity in BC patients and may function as novel biomarkers to diagnose or predict prognosis for BC patients. The exact impact on clinical relevance deserves further study. This review can be an approach to understanding the dual effects of lncRNAs in BC, thereby linking lncRNAs to quasi-personalized treatment in the future.

Long non-coding RNA XIST expression as a prognostic factor in human cancers: A meta-analysis

A large number of literature has shown that high expression of X inactive-specific transcript (XIST) is associated with poor prognosis and metastasis of cancer in patients. However, most of this literature is limited by the small sample sizes and discrete outcomes. Therefore, a meta-analysis was performed to investigate the relation between XIST expression and tumor node metastasis (TNM) stage, lymph node metastasis, distant metastasis, and overall survival of cancer patients. We searched for literature in PubMed, Embase, and Web of Science. The pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to evaluate the association of XIST expression with prognosis and clinicopathological characteristics of cancer patients. Finally, a total of 14 articles involving 1123 patients were included in this meta-analysis. The results suggested that high expression of XIST has a significant relationship with a relatively poor overall survival for patients with malignant tumors (HR 1.82; 95% CI 1.32, 2.52; P = 0.0003). Moreover, high expression of XIST was significantly associated with poor TNM stage (OR 3.64; 95% CI 2.62, 5.07; P < 0.0001), lymph node metastasis (OR 2.39; 95% CI 1.65, 3.46; P < 0.0001) and distant metastasis (OR 2.84; 95% CI 1.90, 4.23; P < 0.0001). In conclusion, high expression of lncRNA XIST may be a predictive factor of poor prognosis in human cancers.

Clinical utility of circulating non-coding RNAs - an update

Over the past decade, the amount of research and the number of publications on associations between circulating small and long non-coding RNAs (ncRNAs) and cancer have grown exponentially. Particular focus has been placed on the development of diagnostic and prognostic biomarkers to enable efficient patient management - from early detection of cancer to monitoring for disease recurrence or progression after treatment. Owing to their high abundance and stability, circulating ncRNAs have potential utility as non-invasive, blood-based biomarkers that can provide information on tumour biology and the effects of treatments, such as targeted therapies and immunotherapies. Increasing evidence highlights the roles of ncRNAs in cell-to-cell communication, with a number of ncRNAs having the capacity to regulate gene expression outside of the cell of origin through extracellular vesicle-mediated transfer to recipient cells, with implications for cancer progression and therapy resistance. Moreover, 'foreign' microRNAs (miRNAs) encoded by non-human genomes (so-called xeno-miRNAs), such as viral miRNAs, have been shown to be present in human body fluids and can be used as biomarkers. Herein, we review the latest developments in the use of circulating ncRNAs as diagnostic and prognostic biomarkers and discuss their roles in cell-to-cell communication in the context of cancer. We provide a compendium of miRNAs and long ncRNAs that have been reported in the literature to be present in human body fluids and that have the potential to be used as diagnostic and prognostic cancer biomarkers.

Up-regulated lncRNA XIST contributes to progression of cervical cancer via regulating miR-140-5p and ORC1

Background

The study purpose was to make investigation into the influence of XIST on cervical cancer progression and what’s more its potential mechanism.

Methods

The cervical cancer data sets (lncRNA, miRNA, and mRNA) obtained from TCGA were analyzed with the “mixOmics” R package. Then, the expression of XIST, miR-140-5p, and ORC1 were detected using qRT-PCR and western blot in both tissues and cervical cancer cell lines (Hela and C33A) to verify the bioinformatics analyses results. CCK-8 assay, 5-ethynyl-2′-deoxyuridine (EdU) assays, cell cycle assay and cell apoptosis assay were practiced. Besides, immunohistochemistry staining was operated for the detection of the Ki-67, E-cadherin and vimentin expression in cervical cancer tissues and the apoptosis-related proteins expression (c-caspase3, Bcl-2, total PARP and cleaved PARP) was verified through western blot. And in vivo experiments were implemented.

Results

MiR-140-5p was down-regulated but XIST and ORC1 were up-regulated in cervical cancer tissues and cell lines. Knocking down of the XIST or ORC1 memorably suppressed cell proliferation, blocked cell cycle, decreased the expression of Bcl-2 while increased the apoptosis rate and the expression of c-caspase3 and cleaved PARP in HeLa and C33A cells. Besides, the results of immunohistochemistry staining showed knocking down the expression of XIST improved the expression levels of E-cadherin and decreased Ki-67 and vimentin expression. And overexpression of miR-140-5p also could inhibit the progression and reverse the influence of XIST and ORC1 in HeLa and C33A cells.

Conclusion

Our study indicated the effects of XIST/miR-140-5p/ORC1 axis on the progression of cervical cancer which will shed new light on epigenetic diagnostics and therapeutics in cervical cancer.

LncRNA XIST facilitates proliferation and epithelial-mesenchymal transition of colorectal cancer cells through targeting miR-486-5p and promoting neuropilin-2

This study was designed to acertain whether the long noncoding RNA (lncRNA) X-inactive specific transcript (XIST)/miR-486-5p/neuropilin-2 (NRP-2) pathway might promote the viability and epithelial-mesenchymal transition (EMT) of colorectal cancer (CRC) cells. In this investigation, we included 317 pathologically confirmed CRC patients and purchased several human CRC cells (i.e. HCT116, HT29, SW620, and SW480). Moreover, pcDNA3.1-XIST, si-XIST, miR-486-5p mimic, miR-486-5p inhibitor, and pcDNA3.1-NRP-2 were transfected into the CRC cells. And the dual-luciferase reporter gene assay managed to verify the targeted relationships among XIST, miR-486-5p, and NRP-2. Ultimately, the MTT assay, flow cytometry, colony formation assay, and transwell assay were carried out to assess the influence of XIST, miR-486-5p, and NRP-2 on the proliferation, apoptosis, migration, and invasion of CRC cells. Our study results demonstrated that CRC tissues and cells were detected with significantly elevated XIST and NRP-2 expressions as well as markedly reduced miR-486-5p expression when compared with normal tissues and cells (all p < 0.05). Besides this, the highly expressed XIST and NRP-2, as well as the lowly expressed miR-486-5p all could substantially encourage proliferation and EMT of CRC cells and simultaneously restrict apoptosis of the cells ( p < 0.05). Moreover, XIST was found to directly target miR-486-5p, and NRP-2 was directly targeted and modulated by miR-486-5p. Finally, CRC cells of the miR-NC + pcDNA3.1-NRP-2 groups showed stronger proliferation, viability, and EMT than those of miR-NC and miR-486-5p mimic groups ( p < 0.05). In conclusion, the XIST/miR-486 -5p/NRP-2 axis appeared to participate in the progression of CRC, which could assist in developing efficacious therapies for CRC.

Multidimensional communication of microRNAs and long non-coding RNAs in lung cancer

PURPOSE

Non-coding RNAs (ncRNAs) have been a hot topic for many years in the field of cancer research, especially miRNAs and lncRNAs. Because they play critical roles in regulating various cellular processes and are more often involved in tumorigenesis than protein-coding genes. But the cross talk between miRNAs and lncRNAs in cancer has been scarcely studied. This article aims to provide a retrospective review of the latest research on the link between miRNAs and lncRNAs in lung cancer and discusses their potential role as diagnostic biomarkers and therapeutic targets for lung cancer in clinical practice.

METHODS

We reviewed literatures about ncRNAs and lung cancer from PUBMED databases in this article.

RESULTS

As shown in our review, miRNAs and lncRNAs could represent underlying targets for diagnosis, therapy, prognosis, and drug resistence of lung cancer. By acting as ceRNAs, lncRNAs can competitively inhibit the expression levels of miRNAs, and the lncRNA/miRNA axis can contribute to tumorigenesis, metastasis, and mutidrug resistance in lung cancer via various classic signaling pathways or related proteins.

CONCLUSION

Based on present knowledge, ncRNAs may provide a novel perspective to understand the pathogenesis of lung cancer and could be candidates in screening of therapeutic targets for lung cancer.

LncRNA XIST regulates myocardial infarction by targeting miR-130a-3p

The study was used to probe long noncoding RNA X-inactive specific transcript (lncRNA XIST) RNA expression profile and its influence on cell cycle, proliferation, and apoptosis in myocardial cells. We also aimed to explore the possible meditating relationship between XIST, PDE4D, and miR-130a-3p. Gene differential analysis was carried out using human lncRNA Microarray V3.0. quantitative real-time PCR was used to test mRNA expressions of XIST, miR-130a-3p, and PDE4D in normal cells and postmyocardial infarction (MI) cells. Western blot was applied to determine the protein expression profile of PED4D. Changes in viability and cell cycle/apoptosis of post-MI myocardial cells after silencing of XIST or PDE4D were investigated by MTT assay and flow cytometry, respectively. The targeting relationship between miR-130a-3p and XIST, PDE4D in myocardial cells were verified by dual luciferase reporter assay. Simulated MI environment was constructed by performing anoxic preconditioning in normal cells to probe the influence of XIST on myocardial cell apoptosis. XIST and PDE4D were overexpressed in post-MI myocardial cells, whereas miR-130a-3p was underexpressed in post-MI myocardial cells. High-expressed XIST and PDE4D both promoted myocardial cell apoptosis. High-expressed XIST also inhibited myocardial cell proliferation. XIST-downregulated miR-130a-3p and PDE4D was a direct target of miR-130a-3p. LncRNA XIST promotes MI by targeting miR-130a-3p. MI induced by PDE4D can be reversed by miR-130a-3p.

LncRNA XIST/miR-34a axis modulates the cell proliferation and tumor growth of thyroid cancer through MET-PI3K-AKT signaling

BACKGROUND

Thyroid cancer is one of the most prevalent malignancies in endocrine system. Further understanding and revealing the molecular mechanism underlying thyroid cancer are indispensable for the development of effective diagnosis and treatments. In the present study, we attempted to provide novel basis for targeted therapy for thyroid cancer from the aspect of lncRNA-miRNA-mRNA interaction.

METHODS

The expression and cellular function of XIST (X-inactive specific transcript) was determined. miRNAs which may be direct targets of XIST were screened for from online GEO database and miR-34a was selected. Next, the predicted binding between XIST and miR-34a, and the dynamic effect of XIST and miR-34a on downstream MET (hepatocyte growth factor receptor)-PI3K (phosphoinositide 3-kinase)-AKT (α-serine/threonine-protein kinase) signaling was evaluated.

RESULTS

XIST was significantly up-regulated in thyroid cancer tissues and cell lines; XIST knockdown suppressed the cell proliferation in vivo and the tumor growth in vitro. Based on online database and online tool prediction results, miR-34a was underexpressed in thyroid cancer and might be a direct target of XIST. Herein, we confirmed the negative interaction between XIST and miR-34a; moreover, XIST knockdown could reduce the protein levels of MET, a downstream target of miR-34a, and the phosphorylation of PI3K and AKT. In thyroid cancer tissues, MET mRNA and protein levels of MET were up-regulated; MET was positively correlated with XIST while negatively correlated with miR-34a, further confirming that XIST serves as a ceRNA for miR-34a through sponging miR-34a, competing with MET for miR-34a binding, and finally modulating thyroid cancer cell proliferation and tumor growth.

CONCLUSION

In the present study, we provided novel experimental basis for targeted therapy for thyroid cancer from the aspect of lncRNA-miRNA-mRNA interaction.

LncRNA XIST/miR-200c regulates the stemness properties and tumourigenicity of human bladder cancer stem cell-like cells

Background

The abnormal expression of non-coding RNAs (ncRNAs), such as microRNAs and long ncRNAs, often contribute to the development of cancers. miR-200c functions as a tumour suppressor that impacts the growth of bladder cancer cells and the epithelial-to-mesenchymal transition (EMT). LncRNA X inactive specific transcript (XIST) is highly expressed in tumour tissues, promotes cancer progression and might act as an miRNA molecular sponge. This study aimed to examine the relationship between lncRNA XIST and miR-200c and to assess their functions in the regulation of the stemness properties and tumourigenicity of human bladder cancer stem cell (BCSC)-like cells.

Methods

Biological effects including cell clone formation, sphere formation, self-renewal properties and mouse tumourigenesis were examined in BCSC-like cells with miR-200c overexpression or XIST knockdown. Real-time PCR and western blotting were used to detect the expression changing of related factors in BCSC-like cells gene models. Dual luciferase reporter assay was used to examine the changes of XIST and miR-200c expression levels.

Results

The results indicated that miR-200c overexpression and XIST knockdown could inhibit cell clone formation, self-renewal ability and EMT in BCSC-like cells. miR-200c knockdown could restore the tumour growth inhibition caused by XIST knockdown.

Conclusion

LncRNA XIST may act as an inhibitor of miR-200c to regulate the stemness properties and tumourigenicity of bladder cancer cells, and our findings might reveal a potential strategy of targeting XIST for bladder cancer therapy.

XIST/miR-544 axis induces neuropathic pain by activating STAT3 in a rat model

An increasing number of studies have reported that lncRNAs are responsible for the development of neuropathic pain. In our current study, chronic constriction injury (CCI) rat models were established and we observed that lncRNA XIST was greatly increased. Knockdown of XIST can relieve pain characteristics including both mechanical and thermal hyperalgesia in CCI rats. Meanwhile, XIST down-regulation could inhibit neuro-inflammation by reducing expression of inflammatory cytokines including tumor necrosis factor (TNF)-α, IL-1β, and IL-6 and in CCI rats. By performing bioinformatics technology, miR-544 was predicted to have interactions with XIST and dual-luciferase reporter assays validated the correlation between them. A negative correlation between miR-544 and XIST was observed by carrying out XIST loss or gain of function tests. miR-544 markedly alleviated neuropathic pain development in CCI rats via targeting inflammatory cytokines, which was reversed by XIST over-expression. Moreover, STAT3 was manifested to be a target gene of miR-544 by bioinformatics predictions and it was activated in CCI rats. Over-expression of STAT3 was able to induce neuropathic pain and miR-544 inhibited this process in vivo. Furthermore, XIST increased STAT3 expression by sponging miR-544 in neuropathic pain development. To conclude, our present study indicated that XIST can contribute to neuropathic pain progression in rats through down-regulating miR-544 and up-regulating STAT3. Our results suggested that XIST/miR-544/STAT3 axis can serve as a novel therapeutic target in neuropathic pain development.