LncRNA-DANCR contributes to lung adenocarcinoma progression by sponging miR-496 to modulate mTOR expression

Construction and validation of a prognostic model of lncRNAs associated with RNA methylation in lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is a common type of lung cancer and one of the leading causes of cancer death worldwide. Long non-coding RNAs (lncRNAs) play a crucial role in tumors. The purpose of this study was to explore the expression of lncRNAs associated with RNA methylation modification and their prognostic value in LUAD.

Methods

The RNA sequencing and clinical data were downloaded from The Cancer Genome Atlas dataset, and the messenger RNA and lncRNAs were annotated by Ensemble. The lncRNAs related to RNA methylation regulators (RMlncRNAs) were filtered by Pearson correlation analysis between differentially expressed lncRNAs and RNA methylation regulators. Univariate Cox regression analysis, multivariate Cox regression analysis, and least absolute shrinkage and selection operator regression analysis were used to construct a prognostic model. The receiver operating characteristic curve (ROC) was plotted to validate the predictive value of the prognostic model. Then, tumor mutational burden (TMB) and microsatellite instability were used to compare the immunotherapy response. Finally, to perform a drug sensitivity analysis, the half-maximal inhibitory concentration (IC50) of targeted drugs was calculated using pRRophetic package.

Results

In total, 18 RMlncRNAs associated with the prognosis of LUAD patients were identified. Then, six feature lncRNAs (NFYC-AS1, OGFRP1, MIR4435-2HG, TDRKH-AS1, DANCR, and TMPO-AS1) were used to construct a prognostic model. The ROC curves for training, testing, and validation sets showed that the prognosis model was effective. The subindex based on the prognostic model had a high correlation with TMB. The high-risk group might be subject to greater immune resistance according to the comparison of Tumor Immune Dysfunction and Exclusion scores. Finally, the IC50 of 11 drugs had differences between high- and low-risk group, and only three of the drug's target genes (ERBB4, CASP8, and CD86) were differentially expressed.

Conclusions

In conclusion, a prognostic model based on six feature lncRNAs (NFYC-AS1, OGFRP1, MIR4435-2HG, TDRKH-AS1, DANCR, and TMPO-AS1) was constructed by bioinformatics analysis, which might provide a new insight into the evaluation and treatment of LUAD.

LINC02466 promotes the progression of hepatocellular carcinoma through the mTOR pathway

OBJECTIVE

Long non-coding RNAs (lncRNAs) LINC02466 is an lncRNA newly linked to the adverse outcomes in primary liver cancer patients, and its crucial involvement in the disease's escalation. Decoding the specific role of LINC02466 in HCC progression is of great significance to provide a potential therapeutic target for HCC.

METHODS

RT-qPCR and Western Blot techniques was used to analyze the expression levels of LINC02466 in both malignant and surrounding healthy liver tissues. CCK8 assays and colony formation experiments indicates the LINC02466's effect on the proliferation rates of liver cancer cells. Flow cytometry was pivotal in revealing its significant influence on the cell cycle of these cells. Kaplan-Meier survival analysis with log-rank tests were employed.

RESULTS

The suppression of LINC02466 markedly reduces the stemness attributes of liver cancer cells, indicating a potential therapeutic target. LINC02466 overexpression significantly increased tumor growth rates and final volumes. Further research indicated that LINC02466 significantly influences liver cancer progression through regulating the mTOR signaling pathway.

CONCLUSION

LINC02466 regulating cell proliferation, the cell cycle, and stemness characteristics via the mTOR pathway, suggesting LINC02466 as a potential therapeutic target for primary liver cancer.

LncRNA DANCR promotes macrophage lipid accumulation through modulation of membrane cholesterol transporters

The progression of atherosclerosis (AS), the pathological foundation of coronary artery disease (CAD), is featured by massive lipid deposition in the vessel wall. LncRNAs are implicated in lipid disorder and AS, whereas the specific role of lncRNA DANCR in atherogenesis remains unknown. Here, we demonstrated that DANCR promotes macrophage lipid accumulation by regulating the expression of membrane cholesterol transport proteins. qPCR showed that compared to control groups, CAD patients and atherosclerotic mice had higher DANCR levels. Treating human THP-1 macrophages and mouse RAW264.7 macrophages with ox-LDL significantly upregulated the expression levels of DANCR. Oil Red O staining showed that the silence of DANCR robustly reduced, while overexpression of DANCR significantly increased the numbers and size of lipid droplets in ox-LDL-treated THP-1 macrophages. In contrast, the opposite phenomena were observed in DANCR overexpressing cells. The expression of ABCA1, ABCG1, SR-BI, and NBD-cholesterol efflux was increased obviously by DANCR inhibition and decreased by DANCR overexpression, respectively. Furthermore, transfection with DANCR siRNA induced a robust decrease in the levels of CD36, SR-A, and Dil-ox-LDL uptake, while DANCR overexpression amplified the expression of CD36, SR-A and the uptake of Dil-ox-LDL in lipid-laden macrophages. Lastly, we found that the effects of DANCR on macrophage lipid accumulation and the expression of membrane cholesterol transport proteins were not likely related to miR-33a. The present study unraveled the adverse role of DANCR in foam cell formation and its relationship with cholesterol transport proteins. However, the competing endogenous RNA network underlying these phenomena warrants further exploration.

New evidence for a role of DANCR in cancers: a comprehensive review

Cancer remains a leading cause of mortality and poses a substantial threat to public health. Studies have revealed that Long noncoding RNA DANCR is a cytoplasmic lncRNA whose aberrant expression plays a pivotal role in various cancer types. Within tumour biology, DANCR exerts regulatory control over crucial processes such as proliferation, invasion, metastasis, angiogenesis, inflammatory responses, cellular energy metabolism reprogramming, and apoptosis. By acting as a competitive endogenous RNA for miRNAs and by interacting with proteins and mRNAs at the molecular level, DANCR contributes significantly to cancer progression. Elevated DANCR levels have also been linked to heightened resistance to anticancer drugs. Moreover, the detection of circulating DANCR holds promise as a valuable biomarker for aiding in the clinical differentiation of different cancer types. This article offers a comprehensive review and elucidation of the primary functions and molecular mechanisms through which DANCR influences tumours.

Differential expression and clinical significance of long non-coding RNAs in the development and progression of lung adenocarcinoma

With the development of gene testing technology, we have found many different genes, and lncRNA is one of them. LncRNAs refer to a non-protein coding RNA molecule with a length of more than 200bp, which is one of the focuses of research on human malignant diseases such as LUAD. LncRNAs act as an oncogene or inhibitor to regulate the occurrence and progression of tumors. The differential expression of LncRNAs promotes or inhibits the progression of lung adenocarcinoma by affecting cell proliferation, metastasis, invasion, and apoptosis, thus affecting the prognosis and survival rate of patients. Therefore, LncRNAs can be used as a potential target for diagnosis and treatment of cancer. The early diagnosis of the disease was made through the detection of tumor markers. Because lung adenocarcinoma is not easy to diagnose in the early stage and tumor markers are easy to ignore, LncRNAs play an important role in the diagnosis and treatment of lung adenocarcinoma. The main purpose of this article is to summarize the known effects of LncRNAs on lung adenocarcinoma, the effect of differential expression of LncRNAs on the progression of lung adenocarcinoma, and related signal transduction pathways. And to provide a new idea for the future research of lung adenocarcinoma-related LncRNAs.

Hypoxia-Derived Exosomes Promote Lung Adenocarcinoma by Regulating HS3ST1-GPC4-Mediated Glycolysis

OBJECTIVE

The diagnosis of lung adenocarcinoma (LUAD) is often delayed due to the typically asymptomatic nature of the early-stage disease, causing advanced-stage LUAD diagnosis in most patients. Hypoxia is widely recognized as a driving force in cancer progression. Exosomes originating from hypoxic tumor cells promote tumorigenesis by influencing glycolysis, migration, invasion, and immune infiltration. Given these insights, our study aimed to explore the role of hypoxia-derived exosomal long non-coding RNA (lncRNA) OIP5-AS1 in LUAD cell lines and mouse models.

MATERIALS AND METHODS

Exosomes were meticulously isolated and authenticated based on their morphology and biomarkers. The interaction between heparan sulfate (glucosamine) 3-O-sulfotransferase 1 (HS3ST1) and Glypican 4 (GPC4) was examined using immunoprecipitation. The influence of the hypoxia-derived exosomal lncRNA OIP5-AS1 on glycolysis was assessed in LUAD cell lines. The effect of the hypoxia-derived exosomal lncRNA OIP5-AS1 on cell proliferation and metastasis was evaluated using colony formation, cell viability, cell cycle, and apoptosis analyses. Its effects on tumor size were confirmed in xenograft animal models.

RESULTS

Our study revealed the mechanism of the hypoxia-derived exosomal lncRNA OIP5-AS1 in LUAD progression. We discovered that GPC4 promotes HS3ST1-mediated glycolysis and that the hypoxia-derived exosomal lncRNA OIP5-AS1 enhances glycolysis by regulating miR-200c-3p in LUAD cells. Notably, this lncRNA stimulates LUAD cell proliferation and metastasis and fosters LUAD tumor size via miR-200c-3p. Our findings underscore the potential role of the hypoxia-derived exosomal lncRNA OIP5-AS1 in LUAD progression.

CONCLUSIONS

The hypoxia-derived exosomal lncRNA OIP5-AS1 promotes LUAD by regulating HS3ST1-GPC4-mediated glycolysis via miR-200c-3p.

From carcinogenesis to therapeutic avenues: lncRNAs and mTOR crosstalk in lung cancer

Long non-coding RNAs (lncRNAs) have been demonstrated to have a crucial function in the modulation of the activity of genes, impacting a variety of homeostatic processes involving growth, survival, movement, and genomic consistency. Certain lncRNAs' aberrant expression has been linked to carcinogenesis, tumor growth, and therapeutic resistance. They are beneficial for the management of malignancies since they can function as cancer-causing or cancer-suppressing genes and behave as screening or prognosis indicators. The modulation of the tumor microenvironment, metabolic modification, and spread have all been linked to lncRNAs in lung cancer. Recent research has indicated that lncRNAs may interact with various mTOR signalling systems to control expression in lung cancer. Furthermore, the route can affect how lncRNAs are expressed. Emphasizing the function of lncRNAs as crucial participants in the mTOR pathway, the current review intends to examine the interactions between the mTOR cascade and the advancement of lung cancer. The article will shed light on the roles and processes of a few lncRNAs associated with the development of lung cancer, as well as their therapeutic prospects.

LINC00115 regulates lung adenocarcinoma progression via sponging miR-154-3p to modulate Sp3 expression

The most commonly diagnosed and most lethal subtype of lung cancer is lung adenocarcinoma (LUAD). Therefore, more detailed understanding of the potential mechanism and identification of potential targets of lung adenocarcinoma is needed. A growing number of reports reveals that long non-coding RNAs (lncRNAs) play crucial roles in cancer progression. In present study, we found that lncRNA LINC00115 was upregulated in LUAD tissues and cells. Functional studies revealed that LINC00115 knockdown inhibits the proliferation, growth, invasion, and migration of LUAD cells. Mechanically, we indicated that miR-154-3p is target microRNA of LINC00115, and the effect of downregulated LINC00115 on LUAD cells was partially reversed by the miR-154-3p antisense oligonucleotide (ASO-miR-154-3p). Further investigation revealed that Specificity protein 3 (Sp3) directly interacted with miR-154-3p, and the Sp3 level was positively correlated with the LINC00115 expression. Rescue experiments further showed that Sp3 overexpression partially restored the effect of downregulated LINC00115 on LUAD cells. Similarly, in vivo experiments confirmed that downregulated LINC00115 inhibited xenograft growth and Sp3 expression. Our results demonstrated that LINC00115 knockdown inhibited LUAD progression via sponging miR-154-3p to modulate Sp3 expression. These data indicate that the LINC00115/miR-154-3p/Sp3 axis can be a potential therapeutic target of LUAD.

LINC00491 Facilitates Tumor Progression of Lung Adenocarcinoma via Wnt/β-Catenin-Signaling Pathway by Regulating MTSS1 Ubiquitination

Background: Long non-coding RNAs have been reported to be involved in tumorigenesis and progression through different regulatory mechanisms. It has been reported that aberrantly expressed long non-coding RNA LINC00491 promotes malignancy in multiple tumors, while the role of LINC00491 in lung adenocarcinoma (LUAD) is little reported and the mechanism for regulating tumor progression has not been elucidated. Methods: RNA sequencing and the TCGA database were combined to screen differentially expressed lncRNAs that facilitate tumor progression. The expression level of LINC00491 was examined in LUAD clinical samples and in cell lines using RT-qPCR. In vitro experiments including colony formation assay, EdU assay, cell migration and invasion assay and wound healing assay, and in vivo experiments including xenografting subcutaneous tumors and lung metastasis models were performed to investigate the function of LINC00491 in LUAD tumor progressions. RNA pull-down, mass spectrometry, RIP assays and truncation experiments were carried out to explore the proteins binding to LINC00491 and the specific interactions between the RNA-protein complex. Results: Our results showed that LINC0491 was significantly upregulated in LUAD and positively correlated with poor survival. High LINC00491 expression promoted proliferation, migration and invasion, and resulted in a high metastatic burden in LUAD. Using pull-down assay and mass spectrometry, MTSS1 was found binding to LINC00491, and the conducted experiments verified the direct interaction between LINC00491 and MTSS1. Meanwhile, LINC00491 was found to regulate MTSS1 degradation by promoting the MTSS1 ubiquitination level and then activating the Wnt/β-catenin-signaling pathway. LINC00491/MTSS1/β-catenin may act as a complex to facilitate tumor progression. Conclusions: In summary, our results found a novel mechanism in which LINC00491 directly interacts with MTSS1 by affecting its ubiquitination modification to promote LUAD proliferation, migration and invasion, then activating the Wnt/β-catenin-signaling pathway, demonstrating its significant role in tumor progression and suggesting that the LINC00491/MTSS1/Wnt/β-catenin-signaling pathway could serve as a potential therapeutic target for lung adenocarcinoma in the future.

LncRNA-AC009948.5 promotes invasion and metastasis of lung adenocarcinoma by binding to miR-186-5p

Background

Long non-coding RNAs (LncRNAs) has been confirmed to play a crucial role in the development and progression of various cancer types. Here we evaluated the expression profiles of LncRNAs in Lung adenocarcinoma (LUAD) tissues and identified a novel LncRNA, termed LncRNA-AC009948.5. However, the role and potential molecular mechanisms of this novel LncRNA in LUAD carcinogenesis is unknown.

Methods

Regarding the public databases and based on integrating bioinformatics analyses, we determined whether LncRNA-AC009948.5 exerts its oncogenic functions via sponging miR-186-5p in LUAD. Furthermore, we determined whether NCAPG2 was a downstream target of miR-186-5p. Moreover, the expression level and biological function of LncRNA-AC009948.5 in LUAD were determined by qRT-PCR, cell apoptosis, Edu, transwell, wound healing and western blot assays. Besides, xenograft mice were established for validation. We explored the expression of LncRNA-AC009948.5 and its roles in the prognosis of LUAD.

Results

LncRNA expression microarray data indicate that LncRNA-AC009948.5 is upregulated in LUAD samples. The present study confirmed the upregulation of LncRNA-AC009948.5 in LUAD tissues and cells. Encreased expression of LncRNA-AC009948.5 was correlated with tumor size, lymph nodes, distant metastasis and histological grade, and poor prognosis.LncRNA-AC009948.5 knockdown significantly inhibited cell proliferation, migration, and invasion in vitro, as well as tumorigenesis and metastasis in vivo. Conversely, LncRNA-AC009948.5 upregulated had opposite effects. Mechanistically, we elucidated that LncRNA-AC009948.5 could directly bind to miR-186-5p and subsequently suppress expression of the target gene of NCAPG2.

Conclusions

LncRNA-AC009948.5 promotes lung adenocarcinoma cells metastasis via the miR-186-5p/NCAPG2 axis and activation of the EMT process. Which may serve as potential targets for the treatment of LUAD in the future.

Expression analysis of mTOR-associated lncRNAs in multiple sclerosis

mTOR has been shown to be involved in the regulation of immune responses and differentiation of immune cells. This protein is a candidate molecule for unraveling the molecular mechanisms of autoimmune disorders such as multiple sclerosis (MS). We designed the current study to assess expression of MTOR, and four associated long non-coding RNAs (lncRNAs), namely SNHG1, SNHG3, SHNG5 and DANCR in the peripheral blood of patients with MS compared with healthy controls. Analysis of real-time PCR results has shown down-regulation of SNHG5 and DANCR in MS patients compared with controls. Sex of study participants had no significant effect on expression of either genes and the interaction of sex and disease on expression levels of all studied genes were insignificant. There was a significant negative correlation between expression levels of MTOR gene and disease duration. No other significant correlations were detected between genes expressions and clinical/demographic data. SNHG5 and DANCR transcript levels had AUC values of 0.88 and 0.68 in separation of patients with MS from healthy controls, respectively. Taken together, our study suggests participation of two mTOR-related lncRNAs, i.e. SNHG5 and DANCR in the pathophysiology of MS.

LncRNA MNX1-AS1 contributes to lung adenocarcinoma progression by targeting the miR-34a/SIRT1 axis

LncRNA MNX1-AS1 is known to be involved in progression of several tumor types. However, few studies have investigated the molecular mechanism of MNX1-AS1 in lung adenocarcinoma (LAC). To explore the function of MNX1-AS1 in the pathogenesis of LAC, qRT-PCR was performed to show MNX1-AS1 expression. MNX1-AS1 expression in LAC cells was suppressed by siRNA to detect the biologic behavior. The relationships among miR-34a, MNX1-AS1 and SIRT1 were confirmed by pull-down and dual-luciferase reporter assay. Whether MNX1-AS1 was involved in LAC by targeting miR-34a/SIRT1 axis was verified. MNX1-AS1 was up-regulated in LAC, and over-expression of MNX1-AS1 was significantly associated with lymph node metastasis and poor prognosis. In A549 and H1299 cells, cell proliferation, migration, and invasion were suppressed, the cell cycle was regulated, as well as apoptosis was increased after silencing MNX1-AS1. Mechanistically, MNX1-AS1 served as a ceRNA of miR-34a to down-regulate miR-34a expression. SIRT1 is targeted by miR-34a and its expression is regulated by MNX1-AS1 and miR-34a. Up-regulation of SIRT1 salvaged the effect of silencing MNX1-AS1 on A549 and H1299 cells, to some extent. These results showed that MNX1-AS1 contributes to LAC progression by targeting the miR-34a/SIRT1 axis.

Regulating Oncogenic LncRNA DANCR with Targeted ECO/siRNA Nanoparticles for Non-Small Cell Lung Cancer Therapy

Long noncoding RNA (lncRNA) differentiation antagonizing noncoding RNA (DANCR) is a proven oncogenic lncRNA across multiple cancer types. Its effects on cancer cell migration and invasion position it as a potential target for therapy on multiple levels of gene regulation. DANCR is overexpressed in non-small cell lung cancer (NSCLC), the most common lung cancer subtype with poor patient survival. To effectively deliver small interfering RNA (siRNA) against DANCR for NSCLC therapy, we used arginine-glycine-aspartic acid (RGD)-poly(ethylene glycol) (PEG)-(1-aminoethyl)-iminobis[N-oleicylcysteinyl-1-aminoethyl)propionamide] (ECO)/small interfering RNA against DANCR (siDANCR) nanoparticles to transfect A549 and NCI-H1299 cells. Over 90% DANCR silencing was observed along with inhibition of cell migration, invasion, and spheroid formation relative to transfection with negative control siRNA in RGD-PEG-ECO nanoparticles. DANCR knockdown further showed efficacy in reducing migration and invasion of epidermal growth factor receptor (EGFR)-inhibitor resistant NSCLC along with resensitization to the inhibitor. RGD-PEG-ECO/siDANCR demonstrated silencing for up to 7 d following a single transfection. The results suggest nanoparticle-mediated RNA interference against DANCR as a potential approach for NSCLC treatment by regulating cell migration and invasion in addition to improving EGFR inhibitor response.

A review on the role of DANCR in the carcinogenesis

DANCR is an RNA gene located on chr4. This gene has several splice variants. Up-regulation of DANCR has been reported in many types of cancers. This lncRNA is mainly located in the cytoplasm and regulates genes expression at post-transcriptional level. In fact, it acts as a molecular sponge for a variety of miRNAs, including miR-874-3P, miR-335, miR-149, miR-4319, miR-758-3p, miR-216a-5p, miR-874-3p, miR-33a-5p, miR-335-5p, miR-145-3p, miR-665, miR-345-5p and miR-125b-5p. DANCR also regulates activity of PI3K/AKT/NF-κB, Wnt/β-catenin, ERK/SMAD, MAPK, IL-6/JAK1/STAT3, Smad2/3, p53, FAK/PI3K/AKT/GSK3β/Snail pathways. In the current narrative review article, we summarize the roles of DANCR in the carcinogenesis, with an especial emphasis on its role in the development of osteosarcoma and lung, liver, pancreatic and colorectal cancers.

Identification of miRNAs and genes for predicting Barrett's esophagus progressing to esophageal adenocarcinoma using miRNA-mRNA integrated analysis

Barrett's esophagus (BE) is defined as any metaplastic columnar epithelium in the distal esophagus, which predisposes to esophageal adenocarcinoma (EAC). Yet, the mechanism through which BE develops to EAC still remain unclear. Moreover, the miRNA-mRNA regulatory network in distinguishing BE from EAC still remains poorly understood. To identify differentially expressed miRNAs (DEMs) and genes (DEGs) between EAC and BE from tissue samples, gene expression microarray datasets GSE13898, GSE26886, GSE1420 and miRNA microarray datasets GSE16456, GSE20099 were downloaded from Gene Expression Omnibus (GEO) database. GEO2R was used to screen the DEMs and DEGs. Pathway and functional enrichment analysis were performed by DAVID database. The protein-protein interaction (PPI) network was constructed by STRING and been visualized by Cytoscape software. Finnal, survival analysis was performed basing TCGA database. A total of 21 DEMs were identified. The enriched functions and pathways analysis inclued Epstein-Barr virus infection, herpesvirus infection and TRP channels. GART, TNFSF11, GTSE1, NEK2, ICAM1, PSMD12, CTNNB1, CDH1, PSEN1, IL1B, CTNND1, JAG1, CDH17, ITCH, CALM1 and ITGA6 were considered as the hub-genes. Hsa-miR-143 and hsa-miR-133b were the highest connectivity target gene. JAG1 was predicted as the largest number of target miRNAs. The expression of hsa-miR-181d, hsa-miR-185, hsa-miR-15b, hsa-miR-214 and hsa-miR-496 was significantly different between normal tissue and EAC. CDH1, GART, GTSE1, NEK2 and hsa-miR-496, hsa-miR-214, hsa-miR-15b were found to be correlated with survival.

Long Non-coding RNA DANCR in Cancer: Roles, Mechanisms, and Implications

Long non-coding RNA (lncRNA) DANCR (also known as ANCR)—differentiation antagonizing non-protein coding RNA, was first reported in 2012 to suppress differentiation of epithelial cells. Emerging evidence demonstrates that DANCR is a cancer-associated lncRNA abnormally expressed in many cancers (e.g., lung cancer, gastric cancer, breast cancer, hepatocellular carcinoma). Increasing studies suggest that the dysregulation of DANCR plays critical roles in cancer cell proliferation, apoptosis, migration, invasion, and chemoresistance in vitro and tumor growth and metastasis in vivo. Mechanistic analyses show that DANCR can serve as miRNA sponges, stabilize mRNAs, and interact with proteins. Recent research reveals that DANCR can be detected in many body fluids such as serum, plasma, and exosomes, providing a quick and convenient method for cancer monitor. Thus DANCR can be used as a promising diagnostic and prognostic biomarker and therapeutic target for various types of cancer. This review focuses on the role and mechanism of DANCR in cancer progression with an emphasis on the clinical significance of DANCR in human cancers.

KLF5 activates lncRNA DANCR and inhibits cancer cell autophagy accelerating gastric cancer progression

Cancer cell autophagy has been associated with the progression of gastric cancer (GC), but involvement of long noncoding RNAs (lncRNAs) remains unclear. Initial bioinformatics analysis has identified abnormally highly expressed KLF5 in GC, as well as the predicted regulatory mechanism associating with lncRNA DANCR, miR-194, and AKT2. The expression of KLF5, DANCR, and AKT2 in GC tissue was upregulated, and the expression of miR-194 was downregulated. We knocked KLF5 down and manipulated the expression of DANCR, miR-194, and AKT2 to characterize their roles in GC cell viability, autophagy, and apoptosis. The mechanistic investigations revealed that KLF5 activated the transcription of DANCR in the promoter region and elevated its expression. DANCR acted as a miR-194 sponge to repress its expression in GC. MiR-194 targeted and inhibited AKT2 expression. Silencing KLF5 augmented GC cell autophagy, apoptosis and impeded its viability through the DANCR/miR-194/AKT2 axis. The tumor-inhibiting properties of KLF5 knockdown were substantiated in vivo. Together, our study uncovered the oncogenic role of KLF5-dependent lncRNA DANCR transcription in GC in vivo and in vitro, which implicates the miR-194/AKT2 axis in tumor growth regulation, and it may be a potential therapeutic target for human GC.

Construction and Characterization of Long Non-Coding RNA-Associated Networks to Reveal Potential Prognostic Biomarkers in Human Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is one type of the malignant tumors with high morbidity and mortality. The molecular mechanism of LUAD is still unclear. Studies demonstrate that lncRNAs play crucial roles in LUAD tumorigenesis and can be used as prognosis biomarkers. Thus, in this study, to identify more robust biomarkers of LUAD, we firstly constructed LUAD-related lncRNA-TF network and performed topological analyses for the network. Results showed that the network was a scale-free network, and some hub genes with high clinical values were identified, such as lncRNA RP11-173A16 and TF ZBTB37. Module analysis on the network revealed one close lncRNA module, which had good prognosis performance in LUAD. Furthermore, through integrating ceRNAs strategy and TF regulatory information, we identified some lncRNA-TF positive feedback loops. Prognostic analysis revealed that ELK4- and BDP1-related feedback loops were significant. Secondly, we constructed the lncRNA-m6A regulator network by merging all the high correlated lncRNA-m6A regulator pairs. Based on the network analysis results, some key m6A-related lncRNAs were identified, such as MIR497HG, FENDRR, and RP1-199J3. We also investigated the relationships between these lncRNAs and immune cell infiltration. Results showed that these m6A-related lncRNAs were high correlated with tumor immunity. All these results provide a new perspective for the diagnostic biomarker and therapeutic target identification of LUAD.

miR-496 inhibits proliferation via LYN and AKT pathway in gastric cancer

MicroRNAs (miRNAs) operate as tumor suppressor or carcinogen to regulate cell proliferation, metastasis, invasion, differentiation, apoptosis, and metabolic process. In the present research, we investigated the effect and mechanism of miR-496 in human gastric cancer cells. miR-496 was downregulated in two gastric cancer cell lines, AGS and MKN45, compared with normal gastric epithelial cell line GES-1. miR-496 mimics inhibited the proliferation of AGS cells after the transfection for 48 and 72 h. The migration and invasion of AGS cells were also inhibited by the transfection of miR-496 mimics. miR-496 mimics induced the apoptosis through upregulating the levels of Bax and Active Caspase 3 and downregulating the levels of Bcl-2 and Total Caspase 3. Bioinformatics analysis showed that there was a binding site between miR-496 and Lyn kinase (LYN). miR-496 mimics could inhibit the expression of LYN in AGS cells. LYN overexpression blocked the inhibition of tumor cell growth, as well as the inhibition of AKT/mTOR signaling pathway induced by miR-496. In conclusion, miR-496 inhibited the proliferation through the AKT/mTOR signaling pathway via targeting LYN in gastric cancer cells. Our research provides a new potential target for clinical diagnosis and targeted treatment for gastric cancer.

Prognostic significance of lncRNA DANCR expression in human cancers: a systematic review and meta-analysis

Several studies demonstrated that lncRNA differentiation antagonizing non-protein coding RNA (lncRNA DANCR) expression might have the potential capacity to predict the cancer prognosis; however, definite conclusion has not been obtained. The aim of this meta-analysis was to evaluate the prognostic value of lncRNA DANCR expression in cancers. PubMed, Web of Science, Scopus, and Embase were comprehensively searched for relevant studies. Studies meeting all inclusion standards were included into this meta-analysis. The analysis of overall survival (OS), disease-free survival (DFS), or clinicopathological features was conducted. Total 11 studies containing 1154 cancer patients were analyzed in this meta-analysis. The results showed, compared with low lncRNA DANCR expression, high lncRNA DANCR expression was significantly associated with shorter OS (hazard ratio [HR] = 1.85; 95% CI = 1.52–2.26; P<0.01) and DFS (HR = 1.82; 95% CI = 1.43–2.32; P<0.01) in cancers. Besides, high lncRNA DANCR expression predicted deeper tumor invasion (P<0.01), earlier lymph node metastasis (P<0.01), earlier distant metastasis (P<0.01), and more advanced clinical stage (P<0.01) compared with low lncRNA DANCR expression in cancer populations. High lncRNA DANCR expression was associated with worse prognosis compared with low lncRNA DANCR expression in cancers. LncRNA DANCR expression could serve as a prognostic factor of human cancers.

Long non‑coding RNA DANCR represses the viability, migration and invasion of multiple myeloma cells by sponging miR‑135b‑5p to target KLF9

Multiple myeloma (MM) is a malignancy of plasma cells that leads to marrow failure and bone lesions. Numerous studies have verified the link between long non‑coding RNAs (lncRNAs) and MM. The present study aimed to examine the role and underlying mechanism of differentiation antagonizing non‑protein coding RNA (DANCR) in MM cells. The relative expression levels of DANCR, microRNA (miR)‑135b‑5p and Krüppel‑like factor 9 (KLF9) were examined using reverse transcription‑quantitative PCR. Cell viability was assessed using the MTT assay, while relative cell migration and invasion were evaluated using Transwell assays. Moreover, the dual‑luciferase reporter assay was used to examine the interplay between DANCR, miR‑135b‑5p and KLF9. Western blotting was performed to determine the expression level of KLF9. It was found that lncRNA DANCR and KLF9 were downregulated, while miR‑135b‑5p was upregulated in the serum of patients with MM and in MM cells compared with the controls. Overexpressing DANCR or knocking down miR‑135b‑5p reduced the viability of the MM cells, as well as restrained MM cells from migrating and invading. Furthermore, DANCR directly targeted miR‑135b‑5p and was negatively correlated with miR‑135b‑5p. It was also found that KLF9 was targeted by miR‑135b‑5p and was inversely correlated with miR‑135b‑5p expression. The impact of lncRNA DANCR‑mediated suppression on cell viability, invasion and migration was partially abolished by short hairpin RNA KLF9 or miR‑135b‑5p mimics transfection in MM cells. Thus, it was suggested that lncRNA DANCR repressed the viability, migration and invasion of MM cells by sponging miR‑135b‑5p to target KLF9.

Predictions of the dysregulated competing endogenous RNA signature involved in the progression of human lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer worldwide. Until now, the molecular mechanisms underlying LUAD progression have not been fully explained. This study aimed to construct a competing endogenous RNA (ceRNA) network to predict the progression in LUAD.

METHODS

Differentially expressed lncRNAs (DELs), miRNAs (DEMs), and mRNAs (DEGs) were identified from The Cancer Genome Atlas (TCGA) database with a |log2FC|> 1.0 and a false discovery rate (FDR) < 0.05. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interaction (PPI) network, and survival analyses were performed to analyse these DEGs involved in the ceRNA network. Subsequently, the drug-gene interaction database (DGIdb) was utilized to select candidate LUAD drugs interacting with significant DEGs. Then, lasso-penalized Cox regression and multivariate Cox regression models were used to construct the risk score system. Finally, based on the correlations between DELs and DEGs involved in the risk score system, the final ceRNA network was identified. Meanwhile, the GEPIA2 database and immunohistochemical (IHC) results were utilized to validate the expression levels of selected DEGs.

RESULTS

A total of 340 DELs, 29 DEMs, and 218 DEGs were selected to construct the initial ceRNA network. Functional enrichment analyses indicated that 218 DEGs were associated with the KEGG pathway terms "microRNAs in cancer", "pathways in cancer", "cell cycle", "HTLV-1 infection", and the "PI3K-Akt signalling pathway". K-M survival analysis of all differentially expressed genes involved in the ceRNA network identified 24 DELs, 4 DEMs, and 29 DEGs, all of which were significantly correlated with LUAD progression (P< 0.05). Furthermore, 15 LUAD drugs interacting with 29 significant DEGs were selected. After lasso-penalized Cox regression and multivariate Cox regression modelling, PRKCE, DLC1, LATS2, and DPY19L1 were incorporated into the risk score system, and the results suggested that LUAD patients who had the high-risk score always suffered from a poorer overall survival. Additionally, the correlation coefficients between these 4 DEGs and their corresponding DELs involved in the ceRNA network suggested that there were 2 significant DEL-DEG pairs, NAV2-AS2 - PRKCE (r= 0.430, P< 0.001) and NAV2-AS2 - LATS2 (r= 0.338, P< 0.001). And NAV2-AS2 - mir-31 - PRKCE and NAV2-SA2 - mir-31 - LATS2 were finally identified as ceRNA network involved in the progression of LUAD.

CONCLUSIONS

The lncRNA-miRNA-mRNA ceRNA network plays an essential role in predicting the progression of LUAD. These results may improve our understanding and provide novel mechanistic insights to explore prognosis and therapeutic drugs for LUAD patients.

TUG1 knockdown inhibits the tumorigenesis and progression of prostate cancer by regulating microRNA-496/Wnt/β-catenin pathway

Our study aimed to further investigate the roles and molecular mechanisms of lncRNA taurine upregulated gene 1 (TUG1) in the development and progression of PC. RT-qPCR assay was carried out to measure expression of TUG1, miR-496, together with β-catenin, cyclin D1 and c-myc. Protein levels of β-catenin, cyclin D1 and c-myc were detected by western blot assay. Cell proliferative ability was assessed by colony formation assay and CCK-8 assay. Cell migratory and invasive capacities were evaluated by Transwell migration and invasion assay. The interaction between miR-496 and TUG1 was explored by bioinformatics analysis, luciferase reporter assay and RNA immunoprecipitation assay. Mouse xenograft experiments were performed to further investigate the roles and molecular basis of TUG1 in the tumorigenesis of PC in vivo. TUG1 was highly expressed in PC tissues and cells (DU145 and PC3). TUG1 knockdown inhibited proliferation, migration and invasion in DU145 and PC3 cells. Moreover, TUG1 suppressed miR-496 expression by direct interaction. TUG1 overexpression abrogated miR-96-mediated antiproliferation, anti-migration and anti-invasion effects in DU145 and PC3 cells. TUG1 knockdown inactivated Wnt/β-catenin signaling pathway by upregulating miR-496 in DU145 and PC3 cells. Additionally, TUG1 knockdown inhibited DU145 cells derived PC xenograft growth by upregulating miR-496 and inactivating Wnt/β-catenin signaling in vivo. TUG1 knockdown suppressed PC cell proliferation, migration and invasion in vitro and curbed PC xenograft growth in vivo by regulating miR-496/Wnt/ β-catenin signaling pathway, deepening our understanding on etiology of PC.

Long noncoding RNA DANCR confers cytarabine resistance in acute myeloid leukemia by activating autophagy via the miR-874-3P/ATG16L1 axis

Autophagy is an important mechanism involved in the regulation of acute myeloid leukemia (AML) chemoresistance. The long noncoding RNA (lncRNA) differentiation antagonizing non‐protein coding RNA (DANCR) exhibits oncogenic activity in several types of human cancers, including AML, but it remains unclear whether it regulates autophagy and chemoresistance in AML. We report here that cytarabine (Ara‐C) treatment elevates DANCR expression in human AML cells. In addition, DANCR overexpression confers and its knockdown diminishes Ara‐C resistance in human AML cells, suggesting that DANCR positively regulates AML chemoresistance to Ara‐C. Moreover, DANCR promotes autophagy in Ara‐C‐treated human AML cells and acts as a sponge to decrease miR‐20a‐5p expression, thereby upregulating the expression of ATG16L1, a critical component of the autophagy machinery. Importantly, ATG16L1 silencing abrogates DANCR‐promoted autophagy and markedly restores DANCR‐conferred Ara‐C resistance, suggesting that DANCR promotes MIR‐874‐3P/ATG16L1 axis‐regulated autophagy to confer Ara‐C resistance in human AML cells. Together, this study identifies DANCR as a positive regulator of Ara‐C resistance in human AML cells, suggesting this lncRNA as a potential target for overcoming Ara‐C resistance in AML chemotherapy.

Mechanistic role of DANCR in the choreography of signaling pathways in different cancers: Spotlight on regulation of Wnt/β-catenin and JAK/STAT pathways by oncogenic long non-coding RNA

Discovery of non-coding RNAs has paradigmatically shifted our understanding of the multifaceted nature of cancer. It is becoming progressively more understandable that long non-coding RNAs play fundamental role in regulation of cell signaling pathways in different cancers. DANCR has started to gain remarkable appreciation because of its central role in cancer onset and progression. In this review we have attempted to summarize emerging aspects of DANCR-mediated regulation of Wnt/β-catenin and JAK/STAT pathways in different cancers. We have also discussed how DANCR epigenetically inactivated tumor suppressors to promote cancer. There is sufficient experimental evidence related to oncogenic role of DANCR in variety of cancers. However, there is a need to uncover how DANCR modulates various other oncogenic pathways in different cancers.

Long noncoding RNA LINC00520 accelerates lung adenocarcinoma progression via miR-1252-5p/FOXR2 pathway

It has been corroborated that long noncoding RNA (lncRNA) played fundamental function in various human malignancies development including lung adenocarcinoma (lung ADC). In our study, LINC00520 roles in lung ADC tumorigenesis were explored. We found that LINC00520 level was elevated in lung ADC tissues and cell lines. Besides, the LINC00520 expression had a negative connection with miR-1252-5p level in lung ADC tissues. Additionally, our results demonstrated the reciprocal repression influence between LINC00520 and miR-1252-5p. Moreover, luciferase reporter assays, RIP (RNA-binding protein immunoprecipitation) and pull down assays revealed that miR-1252-5p regulated LINC00520 in RISC-dependent. Furthermore, knockdown of LINC00520 inhibited lung ADC cells proliferation, migration and invasion, while co-transfection with a miR-1252-5p inhibitor inverted these influences. Additionally, the findings also demonstrated that FOXR2 was a target of miR-1252-5p; thus, LINC00520 could regulate FOXR2 level. Moreover, LINC00520 silencing suppressed the tumor growth of lung ADC in vivo. In summary, our data indicated that LINC00520 may act as a ceRNA to modulated FOXR2 level by sponging miR-1252-5p, which might bring a potential and effective biomarker to lung ADC treatment.

The Biological Roles of lncRNAs and Future Prospects in Clinical Application

Chemo and radiation therapies are the most commonly used therapies for cancer, but they can induce DNA damage, resulting in the apoptosis of host cells. DNA double-stranded breaks (DSBs) are the most lethal form of DNA damage in cells, which are constantly caused by a wide variety of genotoxic agents, both environmentally and endogenously. To maintain genomic integrity, eukaryotic organisms have developed a complex mechanism for the repair of DNA damage. Researches reported that many cellular long noncoding RNAs (lncRNAs) were involved in the response of DNA damage. The roles of lncRNAs in DNA damage response can be regulated by the dynamic modification of N6-adenosine methylation (m6A). The cellular accumulation of DNA damage can result in various diseases, including cancers. Additionally, lncRNAs also play roles in controlling the gene expression and regulation of autophagy, which are indirectly involved with individual development. The dysregulation of these functions can facilitate human tumorigenesis. In this review, we summarized the origin and overview function of lncRNAs and highlighted the roles of lncRNAs involved in the repair of DNA damage.

Competing endogenous RNAs in lung cancer

Competing endogenous RNAs (ceRNAs) containing microRNA response elements can competitively interact with microRNA via miRNA response elements, which can combine non-coding RNAs with protein-coding RNAs through complex ceRNA networks. CeRNAs include non-coding RNAs (long non-coding RNAs, circular RNAs, and transcribed pseudogenes) and protein-coding RNAs (mRNAs). Molecular interactions in ceRNA networks can coordinate many biological processes; however, they may also lead to ceRNA network imbalance and thus contribute to cancer occurrence when disturbed. Recent studies indicate that many dysregulated RNAs derived from lung cancer may function as ceRNAs to regulate multitudinous biological functions for lung cancer, including tumor cell proliferation, apoptosis, growth, invasion, migration, and metastasis. This study therefore reviewed the research progress in the field of non-coding and protein-coding RNAs as ceRNAs in lung cancer, and highlighted validated ceRNAs involved in biological lung cancer functions. Furthermore, the roles of ceRNAs as novel prognostic and diagnostic biomarkers were also discussed. Interpreting the involvement of ceRNAs networks in lung cancer will provide new insight into cancer pathogenesis and treatment strategies.

Hypoxia-associated alternative splicing signature in lung adenocarcinoma

Aim: To establish a signature based on hypoxia-related alternative splicing (AS) events for lung adenocarcinoma. Materials & methods: The least absolute shrinkage and selection operator Cox approach was used to construct a prognostic model. A nomogram that integrates the final AS predictor and stage was created. The network of the key AS events and splicing factors was created. Results: We created a prognostic signature of 11 AS events. Moreover, a nomogram that constitutes the pathological stage and risk was exhibited to be greatly effective in estimating the survival likelihood of lung adenocarcinoma patients. Conclusion: Herein we developed the first-ever signature based on hypoxia-related AS events with both prognostic predictive power and diagnostic efficacy.

Long Noncoding RNA DANCR Activates Wnt/β-Catenin Signaling through MiR-216a Inhibition in Non-Small Cell Lung Cancer

Long noncoding RNA differentiation antagonizing nonprotein coding RNA (lncRNA-DANCR) is associated with poor prognosis in multiple cancers, and promotes cancer stemness and invasion. However, the exact mechanisms by which DANCR promotes non-small cell lung cancer (NSCLC) remain elusive. In this study, we determined that DANCR knockdown (KD) impeded cell migration and reduced stem-like characteristics in two NSCLC cell lines, A549 and H1755. Wnt signaling was shown to promote NSCLC proliferation, stemness, and invasion; therefore, we hypothesized that DANCR may regulate these activities through induction of the Wnt/β-catenin pathway. DANCR KD reduced β-catenin signaling and protein expression, and decreased the expression of β-catenin gene targets c-Myc and Axin2. One of the well-defined functions of lncRNAs is their ability to bind and inhibit microRNAs. Through in silico analysis, we identified tumor suppressor miR-216a as a potential binding partner to DANCR, and confirmed this binding through coimmunoprecipitation and luciferase-reporter assays. Furthermore, we show that DANCR-induced β-catenin protein expression may be blocked with miR-216a overexpression. Our findings illustrate a role of DANCR in NSCLC migration and stemness, and suggest a novel DANCR/miR-216a signaling axis in the Wnt/β-catenin pathway.

Comprehensive analysis of prognostic biomarkers in lung adenocarcinoma based on aberrant lncRNA-miRNA-mRNA networks and Cox regression models

Lung adenocarcinoma (LUAD) is the leading cause of cancer-related death worldwide, and its underlying mechanism remains unclear. Accumulating evidence has highlighted that long non-coding RNA (lncRNA) acts as competitive endogenous RNA (ceRNA) and plays an important role in the occurrence and development of LUAD. Here, we comprehensively analyzed and provided an overview of the lncRNAs, miRNAs, and mRNAs associated with LUAD from The Cancer Genome Atlas (TCGA) database. Then, differentially expressed lncRNAs (DElncRNA), miRNAs (DEmiRNA), and mRNAs (DEmRNA) were used to construct a lncRNA–miRNA–mRNA regulatory network according to interaction information from miRcode, TargetScan, miRTarBase, and miRDB. Finally, the RNAs of the network were analyzed for survival and submitted for Cox regression analysis to construct prognostic indicators. A total of 1123 DElncRNAs, 95 DEmiRNAs, and 2296 DEmRNAs were identified (|log₂FoldChange| (FC) > 2 and false discovery rate (FDR) or adjusted P value < 0.01). The ceRNA network was established based on this and included 102 lncRNAs, 19 miRNAs, and 33 mRNAs. The DEmRNAs in the ceRNA network were found to be enriched in various cancer-related biological processes and pathways. We detected 22 lncRNAs, 12 mRNAs, and 1 miRNA in the ceRNA network that were significantly associated with the overall survival of patients with LUAD (P < 0.05). We established three prognostic prediction models and calculated the area under the 1,3,5-year curve (AUC) values of lncRNA, mRNA, and miRNA, respectively. Among them, the prognostic index (PI) of lncRNA showed good predictive ability which was 0.737, 0.702 and 0.671 respectively, and eight lncRNAs can be used as candidate prognostic biomarkers for LUAD. In conclusion, our study provides a new perspective on the prognosis and diagnosis of LUAD on a genome-wide basis, and develops independent prognostic biomarkers for LUAD.

linc00968 inhibits the tumorigenesis and metastasis of lung adenocarcinoma via serving as a ceRNA against miR-9-5p and increasing CPEB3

Increasing evidence confirms that long noncoding RNAs (lncRNAs) exert vital functions in multiple biological process among malignant cancers. In the current study, we uncovered that linc00968 was downregulated in lung adenocarcinoma (LUAD). Furthermore, the low level of linc00968 was correlated with worse prognosis in patients with LUAD. Upregulation of linc00968 restrained the growth and metastatic phenotypes of LUAD cell in vitro and in vivo. Using bioinformation methods and luciferase reporter assay, we identified that linc00968 acted as a competing endogenous RNA (ceRNA) via sponging miR-9-5p to modulate the level of Cytoplasmic Polyadenylation Element Binding Protein 3 (CPEB3) in LUAD. In addition, LUAD cell migration, colony formation and epithelial-mesenchymal transition (EMT) process were suppressed by linc00968 while these aggressive traits were reversed by miR-142-5p or CPEB3 silencing. Altogether, our work disclosed that linc00968 played a critical role in LUAD and linc00968/miR-9-5p/CPEB3 regulatory axis might be a potential treatment target in LUAD.

A novel lncRNA, loc107985872, promotes lung adenocarcinoma progression via the notch1 signaling pathway with exposure to traffic-originated PM2.5 organic extract

PM2.5 pollution is an important and urgent problem in China that can increase mortality and hospital admissions. Traffic-originated PM2.5 organic component (tPo) mainly contains polycyclic aromatic hydrocarbons (PAHs). Research has shown that PAHs can promote invasion, metastasis, and cancer stem cell properties in lung adenocarcinoma cells, but the exact toxicological mechanism is unknown. In the present study, we investigated the effect of lncRNAs on the progression of lung adenocarcinoma induced by tPo and the underlying mechanisms mediated by lncRNA-signaling pathway interactions. We found that chronic tPo treatment upregulated the expression of loc107985872, which further promoted cell invasion and migration, EMT and cancer stem cell properties via notch1 pathway in lung adenocarcinoma cells. Meanwhile, activation of the notch1 signaling pathway through loc107985872 might be associated with abnormally high expression of its upstream proteins, such as ADAM17, PSEN1 and DLL1. Moreover, tPo exposure induced EMT and the acquisition of cancer stem cell-like properties via the notch1 signaling pathway in vivo. In summary, loc107985872 upregulated by tPo promoted lung adenocarcinoma progression via the notch1 signaling pathway.

SNHG17 upregulates WLS expression to accelerate lung adenocarcinoma progression by sponging miR-485-5p

BACKGROUND

Long non-coding RNAs (lncRNAs) have been uncovered to be essential regulators in the biological processes of human cancers, including lung adenocarcinoma (LUAD). Recently, small nucleolar RNA host gene 17 (SNHG17) has been identified as one novel oncogenic lncRNA in gastric cancer. However, it remains unclear whether SNHG7 exert functions in LUAD progression.

METHODS

The expression levels of SNHG17, miR-485-5p and Wnt ligand secretion mediator (WLS) in LUAD cells was evaluated by RT-qPCR. The effect of SNHG7 silencing on LUAD cell proliferation was assessed by colony formation and EdU assays. The apoptosis of LUAD cells was measured by flow cytometry analysis. Transwell assays were applied to detect cell migration and invasion. The relationship between SNHG17 and miR-485-5p was validated by RIP, RNA pull down and luciferase reporter assays.

RESULTS

SNHG17 and WLS were up-regulated in LUAD cell lines. Down-regulation of SNHG17 curbed LUAD cell proliferation, migration and invasion but facilitated apoptosis. SNHG17 acted as miR-485-5p sponge to upregulate WLS expression.

CONCLUSION

SNHG17 triggers the progression of LUAD via sponging miR-485-5p to upregulate WLS expression.

The functional roles of long noncoding RNA DANCR in Human Cancers

Long noncoding RNAs (lncRNAs) have been wildly explored in various cellular processes and their aberrant expression could lead to tumorigenesis, development and progression. Differentiation antagonizing non-protein coding RNA (DANCR), a well-known lncRNA that is aberrant expression in various tumors, including hepatocellular carcinoma, gastric cancer, colorectal cancer, breast cancer, lung cancer and glioma and so on, in which it functions as oncogene mainly, contributing to cancer development and progression. High expressed DANCR is correlated with poor prognosis. In the present review, we summarize recent progression concerning the role, potential clinical utilities and underlying molecular mechanisms of DANCR related to occurrence and development of multiple cancers.

Crosstalk Between MYC and lncRNAs in Hematological Malignancies

The human genome project revealed the existence of many thousands of long non-coding RNAs (lncRNAs). These transcripts that are over 200 nucleotides long were soon recognized for their importance in regulating gene expression. However, their poor conservation among species and their still controversial annotation has limited their study to some extent. Moreover, a generally lower expression of lncRNAs as compared to protein coding genes and their enigmatic biochemical mechanisms have impeded progress in the understanding of their biological roles. It is, however, known that lncRNAs engage in various kinds of interactions and can form complexes with other RNAs, with genomic DNA or proteins rendering their functional regulatory network quite complex. It has emerged from recent studies that lncRNAs exert important roles in gene expression that affect many cellular processes underlying development, cellular differentiation, but also the pathogenesis of blood cancers like leukemia and lymphoma. A number of lncRNAs have been found to be regulated by several well-known transcription factors including Myelocytomatosis viral oncogene homolog (MYC). The c-MYC gene is known to be one of the most frequently deregulated oncogenes and a driver for many human cancers. The c-MYC gene is very frequently activated by chromosomal translocations in hematopoietic cancers most prominently in B- or T-cell lymphoma or leukemia and much is already known about its role as a DNA binding transcriptional regulator. Although the understanding of MYC's regulatory role controlling lncRNA expression and how MYC itself is controlled by lncRNA in blood cancers is still at the beginning, an intriguing picture emerges indicating that c-MYC may execute part of its oncogenic function through lncRNAs. Several studies have identified lncRNAs regulating c-MYC expression and c-MYC regulated lncRNAs in different blood cancers and have unveiled new mechanisms how these RNA molecules act. In this review, we give an overview of lncRNAs that have been recognized as critical in the context of activated c-MYC in leukemia and lymphoma, describe their mechanism of action and their effect on transcriptional reprogramming in cancer cells. Finally, we discuss possible ways how an interference with their molecular function could be exploited for new cancer therapies.

NNT-AS1 modulates prostate cancer cell proliferation, apoptosis and migration through miR-496/DDIT4 axis

Background

Emerging studies have disclosed long non-coding RNAs (lncRNAs) as pivotal modulators in the progression of prostate cancer (PCa). Current research planned to figure out the involvement of lncRNA nicotinamide nucleotide transhydrogenase antisense RNA 1 (NNT-AS1) in PCa.

Methods

RNA expression was examined using RT-qPCR in PCa cells. Functional assays assessed the viability, proliferation, apoptosis and migration of PCa cells. RNA pull down and luciferase reporter experiments detected the interplay between miRNA and lncRNA or mRNA.

Results

NNT-AS1 was apparently upregulated in PCa cells. NNT-AS1 deficiency abrogated PCa cell viability, proliferation and migration but promoted apoptosis. Besides, miR-496 could be sequestered by NNT-AS1 to elevate the expression of DNA damage inducible transcript 4 (DDIT4) in PCa. Rescue assays indicated that overexpressed DDIT4 or restrained miR-496 could reverse the influence of NNT-AS1 depletion on malignant processes in PCa cells.

Conclusion

NNT-AS1 contributes to the malignant phenotypes of PCa cells through targeting miR-496 to boost DDIT4 expression.

LncRNA DANCR regulates the growth and metastasis of oral squamous cell carcinoma cells via altering miR-216a-5p expression

The study aims to investigate how DANCR can alter the growth and metastasis of oral squamous cell carcinoma (OSCC) cells by regulating miR-216a-5p. The expression of DANCR and miR-216a-5p in OSCC patients and cells were measured. SCC15 and CAL-27 cells were selected to divide into Control, sh-NC, DANCR shRNA, DANCR, miR-216a-5p mimic, and DANCR + miR-216a-5p mimic groups. Dual-luciferase reporter gene assay was performed for the verification of the targeting relationship between miR-216a-5p and DANCR/Bcl-2/KLF12. We also quantified the abilities of OSCC cells regarding proliferation, invasion, migration and apoptosis, and the expression levels of apoptosis-related proteins were measured. Finally, the tumor-bearing nude mice were established to verify the effect of DANCR in vivo. Up-regulated DANCR expression and down-regulated miR-216a-5p expression were observed in both OSCC tissues and cells, and they were proven strongly correlated to the histological grade, clinical staging and lymph node metastasis of OSCC patients. Dual-luciferase reporter gene assay showed a target relationship between DANCR and miR-216a-5p, as well as between miR-216a-5p and Bcl-2/KLF12. Both DANCR shRNA and miR-216a-5p mimic decreased proliferative, migration and invasive abilities of OSCC cells with increased cell apoptosis. However, DANCR group showed completely opposite trends. Moreover, miR-216a-5p mimic could reverse the role of DANCR in promoting tumor growth. In-vivo experiment confirmed the inhibitory role of DANCR shRNA in tumor growth and metastasis. We concluded that DANCR may promote the growth and metastasis of OSCC cells and suppress OSCC cell apoptosis by sponging miR-216a-5p.

IDSSIM: an lncRNA functional similarity calculation model based on an improved disease semantic similarity method

Background

It has been widely accepted that long non-coding RNAs (lncRNAs) play important roles in the development and progression of human diseases. Many association prediction models have been proposed for predicting lncRNA functions and identifying potential lncRNA-disease associations. Nevertheless, among them, little effort has been attempted to measure lncRNA functional similarity, which is an essential part of association prediction models.

Results

In this study, we presented an lncRNA functional similarity calculation model, IDSSIM for short, based on an improved disease semantic similarity method, highlight of which is the introduction of information content contribution factor into the semantic value calculation to take into account both the hierarchical structures of disease directed acyclic graphs and the disease specificities. IDSSIM and three state-of-the-art models, i.e., LNCSIM1, LNCSIM2, and ILNCSIM, were evaluated by applying their disease semantic similarity matrices and the lncRNA functional similarity matrices, as well as corresponding matrices of human lncRNA-disease associations coming from either lncRNADisease database or MNDR database, into an association prediction method WKNKN for lncRNA-disease association prediction. In addition, case studies of breast cancer and adenocarcinoma were also performed to validate the effectiveness of IDSSIM.

Conclusions

Results demonstrated that in terms of ROC curves and AUC values, IDSSIM is superior to compared models, and can improve accuracy of disease semantic similarity effectively, leading to increase the association prediction ability of the IDSSIM-WKNKN model; in terms of case studies, most of potential disease-associated lncRNAs predicted by IDSSIM can be confirmed by databases and literatures, implying that IDSSIM can serve as a promising tool for predicting lncRNA functions, identifying potential lncRNA-disease associations, and pre-screening candidate lncRNAs to perform biological experiments. The IDSSIM code, all experimental data and prediction results are available online at https://github.com/CDMB-lab/IDSSIM.

Resveratrol Suppresses Human Nasopharyngeal Carcinoma Cell Growth Via Inhibiting Differentiation Antagonizing Non-Protein Coding RNA (DANCR) Expression

BACKGROUND Although resveratrol has been found to show anti-cancer effects and potential chemotherapeutic activities in several cancers, the role and molecular mechanisms of resveratrol in nasopharyngeal carcinoma (NPC) remains poorly understood. This study aimed to investigate the effect of resveratrol in NPC progression and its molecular mechanism. MATERIAL AND METHODS Quantitative real-time polymerase chain reaction and western blotting were used to detect the expression of DANCR and PTEN. MTT assay and EdU assay were performed to detect the cell proliferation in NPC cells with different treatment. The effect of resveratrol on cell migration was explored by Transwell migration assay. RNA immunoprecipitation assay and chromatin immunoprecipitation assay were performed to test the interaction between DANCR, EZH2, and PTEN. A mouse xenograft model of NPC cell was established, and immunohistochemistry assay was performed to detect the PTEN expression. RESULTS Resveratrol treatment inhibited NPC cell growth and migration in a dose-dependent manner. Additionally, resveratrol downregulated the expression of DANCR and DANCR overexpressing abrogated the inhibition effect of resveratrol on NPC cell migration. Mechanistically, DANCR could bind to EZH2 and downregulated PTEN expression through mediating the binding of EZH2 on PTEN promoter. Furthermore, rescue experiments suggested resveratrol inhibited NPC cell growth and migration by the DANCR/PTEN pathway. Resveratrol significantly decreased the tumor volume and tumor weight and increased the expression of PTEN. CONCLUSIONS Resveratrol increased PTEN expression and suppressed NPC cell growth and migration through downregulation of DANCR.

DANCR: an emerging therapeutic target for cancer

The discovery of long non-coding RNAs (lncRNAs) revolutionized the current framework for understanding the molecular mechanisms of tumorigenesis and stimulated the search for targeted cancer treatments. Among lncRNAs, differentiation antagonizing non-protein-coding RNA (DANCR) is a newly identified oncogenic gene that is upregulated in diverse cancer types and has a critical role in cancer progression. Herein, we summarize current knowledge regarding DANCR regulatory functions related to cancer cell proliferation, invasion, metastasis, and chemo-resistance. We also synthesize the effects of DANCR on cancer stemness features, the epithelial-mesenchymal transition (EMT), and angiogenesis, which are essential for the progression of malignant cancer cells. Mechanically, the interaction between DANCR and its targets including microRNAs (miRNAs), mRNAs, and proteins are also elucidated. Finally, we propose DANCR-based therapeutic approaches to provide novel insights about cancer treatment.

LINC00689 promotes prostate cancer progression via regulating miR-496/CTNNB1 to activate Wnt pathway

Background

Accumulating evidence has proved the significant influence of long non-coding RNAs (lncRNAs) in cancer formation and development, including PCa.

Methods

The role of LINC00689 in PCa was confirmed by RT-qPCR, MTT, colony formation, flow cytometry, western blot and transwell assays. Besides, the binding ability between LINC00689 and miR-496 was validated by using luciferase reporter assay. Then RT-qPCR, RIP and luciferase reporter and western blot assays were employed to verify the interactions among LINC00689, miR-496 and CTNNB1. Furthermore, the rescuing role of CTNNB1 in Wnt pathway was proved by RT-qPCR, TOP/FOP Flash and western blot assays.

Results

LINC00689 was upregulated in PCa tissues and cells as well as at the terminal stage. Further, knock down of LINC00689 repressed PCa cell proliferation, migration and invasion, and initiated PCa cell apoptosis. Additionally, miR-496 inhibitor and pcDNA3.1/CTNNB1 could neutralize the prohibitive effects of LINC00689 silencing on cell proliferation, migration and invasion, meanwhile, could offset the encouraging role of knocking down LINC00689 in cell apoptosis. Moreover, CTNNB1 upregulation exerted redemptive function in Wnt pathway inhibited by LINC00689 depletion.

Conclusions

To sum up, LINC00689 promotes PCa progression via regulating miR-496/CTNNB1 to activate Wnt pathway, which may contribute to research about new targets for PCa treatment.

LncRNA CRNDE is activated by SP1 and promotes osteosarcoma proliferation, invasion, and epithelial-mesenchymal transition via Wnt/β-catenin signaling pathway

Long noncoding RNAs (lncRNAs) were identified as a vital part in the development and progression of cancer in recent years. Colorectal neoplasia differentially expressed (CRNDE), a lncRNA, functions as an oncogene in some malignant neoplasias, but its role in the progression of osteosarcoma (OS) is still poorly understood. To dissect the difference in the expression of CRNDE, quantitative real-time polymerase chain reaction was utilized to evaluate it in OS tissues and cell lines (U2OS, MG63, and MNNG/HOS) compared with that in the adjacent normal tissues/osteoblast cells (hFOB1.19). The role of CRNDE in OS lines was assessed using Cell Counting Kit-8, colony formation, 5-ethynyl-2'-deoxyuridine staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining, flow cytometry, Transwell assays, and Western blot, respectively. The results demonstrated that the expression of CRNDE was high in OS tissues and cell lines, and partly induced by SP1. CRNDE knockdown attenuated OS cell proliferation and invasion and induced apoptosis and G0/G1 arrest. Moreover, the expression of mesenchymal markers N-cadherin, Vimentin and Snail were downregulated, while the expression of epithelial markers E-cadherin and ZO-1 were conversely upregulated due to CRNDE knockdown. The mechanistic investigations showed that CRNDE promoted glycogen synthase kinase-3β phosphorylation to activate the Wnt/β-catenin pathway. The results suggested that lncRNA CRNDE indeed contributed to OS proliferation, invasion, and epithelial-mesenchymal transition, working as an oncogene, demonstrating that lncRNA CRNDE may be a valid therapeutic target for the OS.

Decreased ZNF750 promotes angiogenesis in a paracrine manner via activating DANCR/miR-4707-3p/FOXC2 axis in esophageal squamous cell carcinoma

ZNF750 is one novel significantly mutated gene identified in esophageal squamous cell carcinoma (ESCC) using next-generation sequencing. However, its clinically relevant and potential mechanisms have remained elusive. Using genomic sequencing of 612 ESCC patients, we analyzed the associations of ZNF750 mutations with clinicopathologic features and its prognostic value. We further investigated the function and underlying mechanism of ZNF750 in angiogenesis. The results showed ZNF750 mutations/deletions are significantly associated with malignant progression and poor prognosis of ESCC patients. Decreased ZNF750 in ESCC cells induces enhanced angiogenesis of human umbilical vein endothelial cells (HUVECs) and human arterial endothelial cells (HAECs), and the effect may be indirectly mediated by FOXC2. RNA-seq and ChIP shows lncRNA DANCR is a direct downstream target of ZNF750. Furtherly, knockdown ZNF750 evokes DANCR expression, which prevents miR-4707-3p to interact with FOXC2 as a microRNA sponge in a ceRNA manner, leading to enhanced FOXC2 signaling and angiogenesis. In contrast, ZNF750 expression reverses the effect. Our study reveals a novel mechanism of ZNF750, highlights a significance of ZNF750 as a metastatic and prognostic biomarker, and offers potential therapeutic targets for ESCC patients harboring ZNF750 mutations.

Exosome-transmitted lncRNA UFC1 promotes non-small-cell lung cancer progression by EZH2-mediated epigenetic silencing of PTEN expression

Long non-coding RNAs (LncRNAs) have been suggested as important regulators of cancer development and progression in non-small cell lung cancer (NSCLC). Nevertheless, the biological roles and clinical significance of lncRNA UFC1 in NSCLC remain unclear. We detected the expression of UFC1 in tumor tissues, serum, and serum exosomes of NSCLC patients by qRT-PCR. Gene overexpression or silencing were used to examine the biological roles of UFC1 in NSCLC. RNA immunoprecipitation and ChIP assays were performed to evaluate the interaction between UFC1 and enhancer of zeste homolog 2 (EZH2) and the binding of EZH2 to PTEN gene promoter. Rescue study was used to access the importance of PTEN regulation by UFC1 in NSCLC progression. UFC1 expression was upregulated in tumor tissues, serum, and serum exosomes of NSCLC patients and high level of UFC1 was associated with tumor infiltration. UFC1 knockdown inhibited NSCLC cell proliferation, migration and invasion while promoted cell cycle arrest and apoptosis. UFC1 overexpression led to the opposite effects. Mechanistically, UFC1 bound to EZH2 and mediated its accumulation at the promoter region of PTEN gene, resulting in the trimethylation of H3K27 and the inhibition of PTEN expression. UFC1 knockdown inhibited NSCLC growth in mouse xenograft tumor models while the simultaneous depletion of PTEN reversed this effect. NSCLC cells derived exosomes could promote NSCLC cell proliferation, migration and invasion through the transfer of UFC1. Moreover, Exosome-transmitted UFC1 promotes NSCLC progression by inhibiting PTEN expression via EZH2-mediated epigenetic silencing. Exosome-mediated transmit of UFC1 may represent a new mechanism for NSCLC progression and provide a potential marker for NSCLC diagnosis.

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.

Angelica Sinensis Polysaccharide Suppresses Epithelial-Mesenchymal Transition and Pulmonary Fibrosis via a DANCR/AUF-1/FOXO3 Regulatory Axis

Idiopathic pulmonary fibrosis (IPF) is characterized by the accumulation of lung fibroblasts and extracellular matrix deposition. Angelica sinensis polysaccharide (ASP), the major bioactive component that can extracted from roots of angelica, plays functional roles in immunomodulation, anti-tumor activity, and hematopoiesis. Emerging evidence has suggested that long noncoding RNAs (lncRNAs) play important roles in pathophysiological processes in various diseases. However, the roles of lncRNAs and ASP in IPF remain poorly understood. In the present study, we investigated the effects of ASP in IPF, as well as their functional interactions with lncRNA DANCR (differentiation antagonizing non-protein coding RNA). IPF models were established by treating Sprague-Dawley rats with BLM and treating alveolar type Ⅱ epithelial (RLE-6TN) cells with TGF-β1. Our results showed that ASP treatment suppressed pulmonary fibrosis in rats and fibrogenesis in RLE-6TN cells. The lncRNA DANCR is downregulated after ASP treatment in both rat lung tissues and RLE-6TN cells, and DANCR overexpression dramatically reversed the suppressive effects of ASP in IPF. Mechanistically, DANCR directly binds with AUF1 (AU-binding factor 1), thereby upregulating FOXO3 mRNA and protein levels. Moreover, overexpression of AUF1 or FOXO3 reversed the functional effects induced by ASP treatment. In conclusion, our findings showed that DANCR mediates ASP-induced suppression of IPF via upregulation of FOXO3 protein levels in an AUF1-dependent manner. Therefore, DANCR could serve as a promising therapeutic target in IPF treatment with ASP.

Co-expression analysis and ceRNA network reveal eight novel potential lncRNA biomarkers in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the most common primary liver cancer in the world, with a high degree of malignancy and recurrence. The influence of the ceRNA network in tumor on the biological function of liver cancer is very important, It has been reported that many lncRNA play a key role in liver cancer development. In our study, integrated data analysis revealed potential eight novel lncRNA biomarkers in hepatocellular carcinoma.

METHODS

Transcriptome data and clinical data were downloaded from the The Cancer Genome Atlas (TCGA) data portal. Weighted gene co-expression network analysis was performed to identify the expression pattern of genes in liver cancer. Then, the ceRNA network was constructed using transcriptome data.

RESULTS

The integrated analysis of miRNA and RNAseq in the database show eight novel lncRNAs that may be involved in important biological pathways, including TNM and disease development in liver cancer. We performed function enrichment analysis of mRNAs affected by these lncRNAs.

CONCLUSIONS

By identifying the ceRNA network and the lncRNAs that affect liver cancer, we showed that eight novel lncRNAs play an important role in the development and progress of liver cancer.

Regulation of mTOR signaling by long non-coding RNA

The mechanistic target of rapamycin (mTOR) is a major signaling hub that coordinates cellular and organismal responses, such as cell growth, proliferation, apoptosis, and metabolism. Dysregulation of mTOR signaling occurs in many human diseases, and there are significant ongoing efforts to pharmacologically target this pathway. Long noncoding RNAs (lncRNA), defined by a length > 200 nucleotides and absence of a long open-reading-frame, are a class of non-protein-coding RNAs. Mutations and dysregulations of lncRNAs are directly linked to the development and progression of many diseases, including cancer, diabetes, and neurologic disorders. Recent findings reveal diverse functions for lncRNA that include transcriptional regulation, organization of nuclear domains, and regulation of proteins or RNA molecules. Despite considerable development in our understanding of lncRNA over the past decade, only a fraction of annotated lncRNAs has been examined for biological function. In addition, lncRNAs have emerged as therapeutic targets due to their ability to modulate multiple pathways, including mTOR signaling. This review will provide an up-to-date summary of lncRNAs that are involved in regulating mTOR pathway.

Expression and functional relevance of long non-coding RNAs in acute myeloid leukemia stem cells

In acute myeloid leukemia (AML), novel therapies are needed to target not only the rapidly dividing AML blasts but also the distinct population of leukemia stem cells (LSCs), which have abnormal self-renewal capacity and increased chemotherapy resistance. Elucidation of the expression and function of deregulated genes in LSCs is critical to specifically target LSCs and may consequently lead to improving outcomes of AML patients. Here, we correlated long non-coding RNA (lncRNA) expression profiles obtained from two RNA-seq datasets of 375 younger (aged <60 years) 76 older (≥60 years) adults with cytogenetically normal AML with a 'core enriched' (CE) gene expression signature (GES) associated with LSCs. We identified a LSC-specific signature of 111 lncRNAs that correlated strongly with the CE-GES. Among the top upregulated LSC-associated lncRNAs, we identified the lncRNA DANCR. Further experiments confirmed that DANCR is upregulated in functionally validated LSC-enriched populations. DANCR knock-down in LSCs resulted in decreased stem-cell renewal and quiescence. Furthermore, we showed that targeting Dancr in vivo using a primary murine model of AML (expressing both Mll partial tandem duplication/Flt3 internal tandem duplication) prolonged the survival of mice after serial transplantation. Our data suggest that LSCs have a distinct lncRNA signature with functional relevance and therapeutic potential.