Upregulated long-non-coding RNA DLEU2 exon 9 expression was an independent indicator of unfavorable overall survival in patients with esophageal adenocarcinoma

Deleted in lymphocytic leukemia 2 (DLEU2): a possible biomarker that holds promise for future diagnosis and treatment of cancer

The mechanism of deleted in lymphocytic leukemia 2 (DLEU2)-long non-coding RNA in tumors has become a major point of interest in recent research related to the occurrence and development of a variety of tumors. Recent studies have shown that the long non-coding RNA DLEU2 (lncRNA-DLEU2) can cause abnormal gene or protein expression by acting on downstream targets in cancers. At present, most lncRNA-DLEU2 play the role of oncogenes in different tumors, which are mostly associated with tumor characteristics, such as proliferation, migration, invasion, and apoptosis. The data thus far show that because lncRNA-DLEU2 plays an important role in most tumors, targeting abnormal lncRNA-DLEU2 may be an effective treatment strategy for early diagnosis and improving the prognosis of patients. In this review, we integrated lncRNA-DLEU2 expression in tumors, its biological functions, molecular mechanisms, and the utility of DLEU2 as an effective diagnostic and prognostic marker of tumors. This study aimed to provide a potential direction for the diagnosis, prognosis, and treatment of tumors using lncRNA-DLEU2 as a biomarker and therapeutic target.

SPARC expression in tumor microenvironment induces partial epithelial-to-mesenchymal transition of esophageal adenocarcinoma cells via cooperating with TGF-β signaling

Secreted protein, acidic and rich in cysteine (SPARC) has been characterized as an oncoprotein in esophageal squamous cell carcinoma (ESCC), but its involvement in the pathological development of esophageal adenocarcinoma (ESAD) remains poorly understood. In this study, we aimed to explore the sources of SPARC in the tumor microenvironment (TME) and its functional role in ESAD. Bioinformatic analysis was conducted using data from The Cancer Genome Atlas (TCGA)-esophageal cancer (ESCA) and Genotype-Tissue Expression (GTEx). ESAD tumor cell line OE33 and OE19 cells were used as in vitro cell models. Results showed that SPARC upregulation was associated with unfavorable disease-specific survival (DSS) in ESAD. ESAD tumor cells (OE33 and OE19) had no detectable SPARC protein expression. In contrast, IHC staining in ESAD tumor tissues suggested that peritumoral stromal cells (tumor-associated fibroblasts and macrophages) were the dominant SPARC source in TME. Exogenous SPARC induced partial epithelial-to-mesenchymal transition of ESAD cells, reflected by reduced CDH1 and elevated ZEB1/VIM expression at both mRNA and protein levels. Besides, exogenous SPARC enhanced tumor cell invasion. When TGFBR2 expression was inhibited, the activation of TGF-β signaling induced by exogenous SPARC was impaired. However, the activating effects were rescued by overexpressing mutant TGFBR2 resistant to the shRNA sequence. Copresence of exogenous SPARC and TGF-β1 induced higher expression of mesenchymal markers and enhanced the invading capability of ESAD cells than TGF-β1 alone. In conclusion, this study suggests a potential cross-talk between ESAD tumor stromal cells and cancer cells via a SPARC-TGF-β1 paracrine network.

Growth arrest-specific 5 lncRNA as a valuable biomarker of chemoresistance in osteosarcoma

Osteosarcoma is the most common primary malignant bone tumour in children and teenagers, and it is characterised by drug resistance and high metastatic potential. Increasing studies have highlighted the critical roles of long noncoding RNAs (lncRNAs) as oncogenes or tumour suppressors as well as new biomarkers and therapeutic targets in osteosarcoma. The growth arrestspecific 5 (GAS5) lncRNA can function as a tumour suppressor in several cancers. The present study aimed to validate GAS5 and other chemoresistanceassociated lncRNAs as biomarkers in a cohort of primary osteosarcoma samples, to obtain predictive information on resistance or sensitivity to treatment. The GAS5 and a panel of lncRNAs related to chemoresistance [SNGH1, FOXD2-AS1, deleted in lymphocytic leukemia (DLEU2) and LINC00963] were evaluated in a cohort of osteosarcoma patients enrolled at the Careggi University Hospital. Total RNA was extracted from formalin-fixed paraffin-embedded (FFPE) tissue sections and the expression levels of the lncRNAs were quantified by qPCR. A bioinformatic analysis on deposited RNA-seq data was performed to validate the qPCR results. Clustering analysis shows that GAS5 could be linked to the expression of isoforms 02 and 04 of the lncRNA DLEU2, whereas the DLEU2 isoform 08 is linked to the lncRNA LINC00963. We found that GAS5 is significantly increased in patients with a good prognosis and is expressed differently between chemosensitive and chemoresistant osteosarcoma patients. However, the results obtained are not concordant with the in-silico analysis performed on the TARGET osteosarcoma dataset. In the future, we would enlarge the case series, including different disease settings.

lncRNA DLEU2 promotes gastric cancer progression through ETS2 via targeting miR-30a-5p

Background

Gastric cancer (GC) remains an important cancer worldwide. Further understanding of the molecular mechanisms of gastric carcinogenesis will enhance the diagnosis and treatment of GC.

Methods

The expression of DLEU2 and ETS2 was analyzed in several GC cell lines using GEPIA online analyze, qRT-PCR and immunohistochemistry. The biological behavior of GC cells was detected by CCK8, clone formation, transwell, wound healing, western blot, and flow cytometry assay. More in-depth mechanisms were studied.

Results

DLEU2 was significantly up-regulated in GC tissues and cell lines. The expression of DLEU2 was significantly associated with pathological grading and TNM stage of GC patients. Furthermore, knockdown of DLEU2 inhibited the proliferation, migration, and invasion of AGS and MKN-45 cells, while overexpression of DLEU2 promoted the proliferation, migration, and invasion of HGC-27 cells. MiR-30a-5p could directly bind to the 3’ UTR region of ETS2. Moreover, DLEU2 bound to miR-30a-5p through the same binding site, which facilitated the expression of ETS2. Knockdown of DLEU2 reduced the protein level of intracellular ETS2 and inhibited AKT phosphorylation, while overexpression of DLEU2 induced the expression of ETS2 and the phosphorylation of AKT. ETS2 was highly expressed in GC tissues. The expression of ETS2 was significantly associated with age, pathological grading, and TNM stage. ETS2 overexpression promoted cell proliferation and migration of AGS and MKN-45 cells. Furthermore, ETS2 overexpression rescued cell proliferation and migration inhibition induced by DLEU2 down-regulation and miR-30a-5p up-regulation in AGS and MKN-45 cells.

Conclusions

DLEU2 is a potential molecular target for GC treatment.

Long noncoding RNA DLEU2 drives the malignant behaviors of thyroid cancer through mediating the miR-205-5p/TNFAIP8 axis

OBJECTIVE

Considering the plight in thyroid cancer therapy, we aimed to find novel therapeutic targets from a molecular perspective.

METHODS

Quantitative real-time PCR (qRT-PCR) and Western blot assay were carried out to determine RNA and protein expression. Cell counting kit-8 (CCK8) assay, flow cytometry, transwell migration assay and aerobic glycolysis analysis were performed to analyze cell proliferation, apoptosis, migration and aerobic glycolysis of thyroid cancer cells. MiRcode and Starbase software were used to search the downstream genes of long noncoding RNA (lncRNA) deleted in lymphocytic leukemia 2 (DLEU2) and microRNA-205-5p (miR-205-5p), and the intermolecular combination was confirmed by dual-luciferase reporter assay. The in vivo role of DLEU2 in tumor growth was verified using the murine xenograft model.

RESULTS

DLEU2 and tumor necrosis factor-α-induced protein 8 (TNFAIP8) were highly expressed in thyroid cancer tissues and cell lines. DLEU2 and TNRAIP8 promoted the proliferation, migration and aerobic glycolysis and restrained the apoptosis of thyroid cancer cells. DLEU2/miR-205-5p/TNFAIP8 signaling axis was identified in thyroid cancer cells. TNFAIP8 overexpression largely rescued the malignant phenotypes in DLEU2-silenced thyroid cancer cells. DLEU2 positively regulated TNFAIP8 expression by acting as miR-205-5p sponge in thyroid cancer cells. DLEU2 silencing blocked the growth of xenograft tumors in vivo.

CONCLUSION

lncRNA DLEU2 exerted a pro-tumor role to promote proliferation, migration and aerobic glycolysis while repressing the apoptosis of thyroid cancer cells via miR-205-5p/TNFAIP8 axis.

Screening for alternative splicing of lncRNA Dleu2 in the mouse liver cell line AML-12

The long non coding RNA deleted in leukemia 2 gene (Dleu2) has recently been demonstrated to be an active player in the progression of several types of cancer, including hepatocellular carcinoma. Dleu2 may serve a role in modulating the downstream effects-mediated by alternative splicing of its multiple exons. However, the proportional expression of these alternative splicing populations of the Dleu2 exons is currently unknown. To determine how Dleu2 could be affected by alternative splicing, a series of alternative splicing primer sets were designed to investigate which transcripts were preferentially activated when Dleu2 was targeted for downregulation or upregulation. A specific Dleu2 small interfering RNA that targeted an exon upstream of the tumor suppressor microRNA site significantly knocked down Dleu2 expression across all the primer sets used, which targeted 13 different alternative splicing transcripts over 5 different promoter sites in the mouse liver cell line, AML-12. Similarly, 50 µM Resveratrol led to significant upregulation of Dleu2 in 11 alternative splicing transcripts. These results show that Dleu2 is capable of successful modulation across alternative splicing transcripts that can be screened, and also that Resveratrol can be a potential nutraceutical, which may potentially lead to novel approaches in the use of lncRNA Dleu2 for diagnostics and regulation.

Identification of DNA-Repair-Related Five-Gene Signature to Predict Prognosis in Patients with Esophageal Cancer

Esophageal cancer (ESCA) is a leading cause of cancer-related mortality, with poor prognosis worldwide. DNA damage repair is one of the hallmarks of cancer. Loss of genomic integrity owing to inactivation of DNA repair genes can increase the risk of cancer progression and lead to poor prognosis. We aimed to identify a novel gene signature related to DNA repair to predict the prognosis of ESCA patients. Based on gene expression profiles of ESCA patients from The Cancer Genome Atlas and gene set enrichment analysis, 102 genes related to DNA repair were identified as candidates. After stepwise Cox regression analysis, we established a five-gene prognostic model comprising DGCR8, POM121, TAF9, UPF3B, and BCAP31. Kaplan-Meier survival analysis confirmed a strong correlation between the prognostic model and survival. Moreover, we verified the clinical value of the prognostic signature under the influence of different clinical parameters. We found that small-molecule drugs (trametinib, selumetinib, and refametinib) could help to improve patient survival. In summary, our study provides a novel and promising prognostic signature based on DNA-repair-related genes to predict survival of patients with ESCA. Systematic data mining provides a theoretical basis for further exploring the molecular pathogenesis of ESCA and identifying therapeutic targets.

Long noncoding RNA DLEU2 affects the proliferative and invasive ability of colorectal cancer cells

Emerging evidence indicates that long noncoding RNAs (lncRNAs) are closely associated with colorectal cancer (CRC) tumorigenesis. One example is lncRNA Deleted in Lymphocytic Leukemia 2 (DLEU2). However, how DLEU2 contributes to CRC is still poorly understood. This study sought to investigate the effects of DLEU2 on CRC pathogenesis, and the underlying mechanism involved. Using a quantitative real-time polymerase chain reaction (qRT-PCR) assay, we demonstrated that the expression levels of DLEU2 in 45 pairs of CRC tissues were higher than those in the corresponding normal colon mucosal tissues. In addition, CRC patients with high DLEU2 expression levels exhibited poor overall survival (OS) and recurrence-free survival (RFS), as determined by analyses and measurements from the GEO and GEPIA databases. When DLEU2 was silenced using short interfering RNA (siRNA) in CRC cell line, the results demonstrated that DLEU2 silencing suppressed CRC cell tumorigenesis in vitro, which was associated with decreased expression of cyclin dependent kinase 6(CDK6), ZEB1, and ZEB2 as well as enhancing the expression of Cyclin-dependent kinase inhibitor 1A (CDKN1A). Taken together, the results of this study suggested that DLEU2 may play critical roles in the progression of CRC and may serve as a prognostic biomarker for CRC.

Deleted in lymphocytic leukemia 2 (DLEU2): An lncRNA with dissimilar roles in different cancers

Deleted in lymphocytic leukemia 2" (DLEU2) is a long non-coding transcript with several splice variants. It has been identified through a comprehensive sequencing of a commonly deleted region in leukemia i.e. the 13q14 region. Afterwards, different investigations reported up-regulation of this long non-coding RNA in several types of cancers. Up-regulation of DLEU2 has been shown to determine poor survival in esophageal, pancreatic, laryngeal, renal, cervical and lung cancers. However, the diagnostic power of DLUE2 has only assessed in two studies; only one them exhibiting promising results. A limitation of most of studies is that they did not differentiate between transcript variants of this lncRNA. Therefore, it is not possible to attribute the observed functions to a certain alternate transcript. In this manuscript, we discuss the results of these studies in three different sections based on the type of experiments.

DLEU2: A Meaningful Long Noncoding RNA in Oncogenesis

BACKGROUND

Long non-coding RNA (lncRNA) with little or no coding ability has shown a variety of biological functions in cancer, including epigenetic regulation, DNA damage, regulation of microRNAs, and participation in signal transduction pathways. LncRNA can be used as an oncogene and tumor suppressor gene through transcriptional regulation in cancer. For example, the over-expressed lncRNA DLEU2 promotes the occurrence of laryngeal cancer, lung cancer, hepatocellular carcinoma, etc., and inhibits the progression of chronic lymphocytic leukemia. Deleted in Lymphocytic Leukemia 2 (DLEU2), as one of the long non-coding RNAs, was first found in chronic lymphoblastic leukemia and drawn into the progress of innumerable cancers. The molecular mechanism of DLEU2 in multiple tumors will be revealed.

METHODS

In this review, current studies on the biological functions and mechanisms of DLEU2 in tumors are summarized and analyzed; related researches are systematically retrieved and collected through PubMed.

RESULTS

DLEU2, a novel cancer-related lncRNA, has been demonstrated to be abnormally expressed in various malignant tumors, including leukemia, esophageal cancer, lung cancer, glioma, hepatocellular carcinoma, malignant pleural mesothelioma, bladder cancer, pancreatic cancer, pharynx and throat cancer, renal clear cell carcinoma, breast cancer, osteosarcoma. Besides, lncRNA DLEU2 has been shown to be involved in the process of proliferation, migration, invasion and inhibition of apoptosis of cancer cells.

CONCLUSION

Due to the biological functions and mechanisms involved in DLEU2, it may represent an available biomarker or potential therapeutic target in a variety of malignant tumors.

lncRNA DLEU2 accelerates gastric cancer growth by downregulating miR-30a-5p

Introduction:

lncRNA DLEU2 has been indicated to act a crucial role in the bioprocess of cancer. But, the role and molecular mechanisms of lncRNA DLEU2 in gastric cancer (GC) remain unknown.

Methods:

The correlation of DLEU2 or miR-30a-5p with the clinical parameters and outcomes of GC patents was implemented by TCGA cohort. Cell viability and invasion were estimated by MTT and Transwell assays. The interplay between DLEU2 and miR-30a-5p was confirmed by a luciferase report assay. The effects of DLEU2 on miR-30a-5p or MMP2/9 were detected by qRT-PCR and Western blot.

Results:

We found that the enhanced expression of DLEU2 was linked to the pathological stage and poor survival in GC patients. Overexpressing DLEU2 prompted the cell proliferation and invasion of AGS cells, but silencing DLEU2 weakened these effects in MKN-28 cells. In addition, DLEU2 could negatively modulate and be bound with miR-30a-5p, which could counteract DLEU2-caused cell proliferation. High expression of miR-30a-5p was linked to a favorable survival in patients with GC.

Conclusion:

Our findings suggested that lncRNA DLEU2 could favor the growth of GC by downregulating miR-30a-5p.

Long noncoding RNA DLEU2 predicts a poor prognosis and enhances malignant properties in laryngeal squamous cell carcinoma through the miR-30c-5p/PIK3CD/Akt axis

Long noncoding RNAs (lncRNAs) have been identified as potential prognostic tools and therapeutic biomarkers for a variety of human cancers. However, the functional roles and underlying mechanisms of key lncRNAs affecting laryngeal squamous cell carcinomas (LSCCs) are largely unknown. Here, we adopted a novel subpathway strategy based on the lncRNA-mRNA profiles from the Cancer Genome Atlas (TCGA) database and identified the lncRNA deleted in lymphocytic leukemia 2 (DLEU2) as an oncogene in the pathogenesis of LSCCs. We found that DLEU2 was significantly upregulated and predicted poor clinical outcomes in LSCC patients. In addition, ectopic overexpression of DLEU2 promoted the proliferation and migration of LSCC cells both in vivo and in vitro. Mechanistically, DLEU2 served as a competing endogenous RNA to regulate PIK3CD expression by sponging miR-30c-5p and subsequently activated the Akt signaling pathway. As a target gene of DLEU2, PIK3CD was also upregulated and could predict a poor prognosis in LSCC patients. In conclusion, we found that the novel LSCC-related gene DLEU2 enhances the malignant properties of LSCCs via the miR-30c-5p/PIK3CD/Akt axis. DLEU2 and its targeted miR-30c-5p/PIK3CD/Akt axis may represent valuable prognostic biomarkers and therapeutic targets for LSCCs.

Comprehensive analysis of lncRNA-associated competing endogenous RNA network and immune infiltration in idiopathic pulmonary fibrosis

Background

Idiopathic pulmonary fibrosis (IPF) is a life-threatening lung disorder with an unknown aetiology. The roles of long non-coding RNAs (lncRNAs) and its related competing endogenous RNAs (ceRNA) network in IPF remains poorly understood. In this study, we aimed to build a lncRNA-miRNA-mRNA network and explore the pathogenesis of IPF.

Methods

We screened differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) between IPF and control lung tissues from two datasets. The ceRNA network was built according to the interactions between DElncRNA, miRNA, and DEmRNA. Functional enrichment analysis of DemRNAs was performed using Metascape. CIBERSORT (Cell type Identification by Estimating Relative Subsets Of known RNA Transcripts) was applied to estimate the fraction of 22 immune cells in IPF and controls lung tissue samples. Then we investigated the correlation between immune cells and clinical traits.

Results

We constructed a lncRNA-miRNA-mRNA network, which was composed of two DElncRNAs, 18 miRNAs, 66 DemRNAs. Functional enrichment analysis showed that the DEmRNAs mainly participated in MicroRNAs in cancer. By applying CIBERSORT, we found that IPF tissue samples had a higher proportion of plasma cells, resting mast cells and a lower proportion of resting NK cells, monocytes, neutrophils compared with control tissue samples. Also, our results indicated that immune cells were associated with the severity of IPF.

Conclusions

In summary, this is the first study to build lncRNA-miRNA-mRNA ceRNA network of IPF, which may improve our understanding of IPF pathogenesis. Our study indicates that immune cells in lung tissues may predict disease severity and participate in the development of IPF. Future prospective studies are required to confirm the findings of the current study.

Bioinformatics analysis of prognosis-related long non-coding RNAs in invasive breast carcinoma

Breast cancer is one of the most common types of cancer among women worldwide and needs more sensitive prognostic biomarkers to improve its treatment. In the present study, differentially expressed long non-coding RNAs (lncRNAs) in invasive breast carcinoma from The Cancer Genome Atlas and cBioPortal database were investigated, identifying 292 differentially expressed lncRNAs in 1,100 cases. By analyzing the overall survival rate, 10 lncRNAs were significantly correlated with poor prognosis. To explore the underlying molecular mechanisms of the 10 prognosis-related lncRNAs, bioinformatic methods were used to predict the potential target miRNAs, mRNAs and proteins, and to construct a lncRNA-miRNA-mRNA regulatory network and lncRNA-protein interaction network. Finally, the functions of the target genes and proteins were insvestigated using Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses. The results showed that these 10 lncRNAs could be novel prognostic markers for invasive breast carcinoma and the present study aimed to provide novel insight into the diagnosis and treatment of breast cancer.