Silencing of DLEU2 suppresses pancreatic cancer cell proliferation and invasion by upregulating microRNA-455

LncRNA DLEU2 contributes to Taxol resistance of gastric cancer cells through regulating the miR-30c-5p-LDHA axis

Gastric cancer (GC) is a human malignancy which is associated with high mortality rate and poor prognosis. In addition to surgery, chemo- and radio-therapies are effective strategies against GC at advanced or metastatic stage. Taxol is a traditionally anti-cancer drug which is applied to various types of cancer. However, development of drug resistance limited the anti-cancer effects of Taxol. Currently, the biological roles and mechanisms of non-coding RNA DLEU2 in Taxol resistant GC remain unclear. This study reported that DLEU2 was significantly upregulated and miR-30c-5p was remarkedly downregulated in gastric tumours and cell lines. Silencing DLEU2 or overexpression of miR-30c-5p effectively increased the Taxol sensitivity of GC cells. Through bioinformatics analysis, RNA pull-down and luciferase assay, we demonstrated that DLEU2 sponged miR-30c-5p to block its expression in GC cells. Moreover, from the established Taxol resistant GC cell line, we detected remarkedly upregulated DLEU2 and downregulated miR-30c-5p expressions and significantly elevated glucose metabolism. Under low glucose condition, Taxol resistant cells were more susceptible to Taxol. In addition, we showed overexpression of miR-30c-5p blocked glucose metabolism through inhibiting the LDHA, a glucose metabolism key enzyme by direct targeting the 3'UTR of LDHA. Finally, rescue experiments validated that restoration of miR-30c-5p in DLEU2-overexpressing Taxol resistant GC cells effectively overcame the DLEU2-promoted Taxol resistance. In summary, this study uncovered new roles and molecular mechanisms of the lncRNA DLEU2-promoted Taxol resistance of gastric cancer cells, presenting the DLEU2-miR-30c-5p-LDHA-glucose metabolism axis a potentially therapeutic target for treatment of Taxol resistant GC.

Huaier suppresses cell viability, migration and invasion in human non-small cell lung cancer via lncRNA DLEU2/miR-212-5p/ELF3 axis

Accumulating studies suggest that Huaier exerts anti-tumor effects through intricate mechanisms. Despite extensive research on its efficacy in lung cancer, further investigation is required to elucidate the molecular mechanism of Huaier. The involvement of long noncoding RNAs (lncRNAs) in the anti-lung cancer effects of Huaier remains unknown. In this study, we found Huaier suppressed cell viability, migration and invasion in non-small cell lung cancer (NSCLC) cells. LncRNA sequencing analysis revealed Deleted in lymphocytic leukemia 2 (DLEU2) to be significantly downregulated in Huaier-treated NSCLC cells. Furthermore, DLEU2 silencing was observed to suppress NSCLC progression, while DLEU2 overexpression attenuated the anti-tumor effects of Huaier in NSCLC, thereby promoting cell viability, migration and invasion of NSCLC. The ceRNA role of DLEU2 had been demonstrated in NSCLC, which directly interacted with miR-212-5p to rescue the repression of E74 Like ETS Transcription Factor 3 (ELF3) by this microRNA. Additionally, Huaier was found to regulate the expression of miR-212-5p and ELF3. Functionally, miR-212-5p inhibitor or ELF3 overexpression reversed the effects of DLEU2 silencing or Huaier treatment, resulting in increased colony formation, migration and invasion in NSCLC. Taken together, these results illuminate the mechanism underlying Huaier's anti-tumor effects via the DLEU2/miR-212-5p/ELF3 signaling pathway, which offers novel insights into the anti-tumor effects of Huaier and constitutes a promising therapeutic target for the treatment in NSCLC.

Functional and Potential Therapeutic Implication of MicroRNAs in Pancreatic Cancer

The alarmingly low five-year survival rate for pancreatic cancer presents a global health challenge, contributing to about 7% of all cancer-related deaths. Late-stage diagnosis and high heterogeneity are the biggest hurdles in treating pancreatic cancer. Thus, there is a pressing need to discover novel biomarkers that could help in early detection as well as improve therapeutic strategies. MicroRNAs (miRNAs), a class of short non-coding RNA, have emerged as promising candidates with regard to both diagnostics and therapeutics. Dysregulated miRNAs play pivotal roles in accelerating tumor growth and metastasis, orchestrating tumor microenvironment, and conferring chemoresistance in pancreatic cancer. The differential expression profiles of miRNAs in pancreatic cancer could be utilized to explore novel therapeutic strategies. In this review, we also covered studies on recent advancements in various miRNA-based therapeutics such as restoring miRNAs with a tumor-suppressive function, suppressing miRNA with an oncogenic function, and combination with chemotherapeutic drugs. Despite several challenges in terms of specificity and targeted delivery, miRNA-based therapies hold the potential to revolutionize the treatment of pancreatic cancer by simultaneously targeting multiple signaling pathways.

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.

SMAD Proteins in TGF-β Signalling Pathway in Cancer: Regulatory Mechanisms and Clinical Applications

Suppressor of mother against decapentaplegic (SMAD) family proteins are central to one of the most versatile cytokine signalling pathways in metazoan biology, the transforming growth factor-β (TGF-β) pathway. The TGF-β pathway is widely known for its dual role in cancer progression as both an inhibitor of tumour cell growth and an inducer of tumour metastasis. This is mainly mediated through SMAD proteins and their cofactors or regulators. SMAD proteins act as transcription factors, regulating the transcription of a wide range of genes, and their rich post-translational modifications are influenced by a variety of regulators and cofactors. The complex role, mechanisms, and important functions of SMAD proteins in tumours are the hot topics in current oncology research. In this paper, we summarize the recent progress on the effects and mechanisms of SMAD proteins on tumour development, diagnosis, treatment and prognosis, and provide clues for subsequent research on SMAD proteins in tumours.

Integrated Analysis of the lncRNA-Associated ceRNA Network in Wilms Tumor via TARGET and GEO Databases

Wilms tumor (WT) is the most common genitourinary renal tumor that typically occurs in children under 15 and is thought to be linked to somatic and germline mutations. However, the specific functional role of competing endogenous RNAs (ceRNAs) and their potential implications in WT remain unclear. In this study, we developed an lncRNA-mediated (long noncoding RNA-mediated) ceRNA network via the R packages for WT with expression data obtained from the tumor alterations relevant for genomics-driven therapy (TARGET) database. Unsupervised hierarchical clustering analysis revealed that the WT specimens could be clearly distinguished from healthy specimens with respect to the expression of disordered RNAs. A total of 1,607 differentially expressed (DE) lncRNAs, 116 DE microRNAs (DEmiRNAs), and 3,262 DE messenger RNAs (DEmRNAs) were identified as WT-specific RNAs, and a lncRNA-miRNA-mRNA ceRNA network with 159 DElncRNAs, 18 DEmiRNAs, 131 DEmRNAs, and 792 interactions was constructed. According to the clinical survival data, 12 DElncRNAs, 5 DEmRNAs, and 2 DEmiRNAs were selected from the ceRNA network that could significantly impact the overall survival of WT patients (P < 0.05). Functional enrichment analysis showed that the biological processes and pathways of DEmRNAs, such as cell cycle and virus infection, may be associated with WT. The present study constructed a dysregulated lncRNA-mediated ceRNA network in WT and discovered that lncRNA-mediated ceRNAs may serve as important regulators in WT development and progression. Survival-associated RNAs may serve as new potential biomarkers, suggesting that the constructed ceRNA network in WT might be important for determining optimal therapeutic strategies.

DLEU2 modulates proliferation, migration and invasion of platelet-derived growth factor-BB (PDGF-BB)-induced vascular smooth muscle cells (VSMCs) via miR-212-5p/YWHAZ axis

DLEU2 has been proved to act as an oncogene in a variety of cancers, but its role in cardiovascular diseases is dearth of research. Thus, this study mainly discussed the effect and possible mechanism of DLEU2 on platelet-derived growth factor-BB (PDGF-BB)-triggered vascular smooth muscle cell (VSMC) injury. To obtain authentic results, the expressions of target genes in atherosclerosis serum were determined by reverse transcription quantitative PCR (RT-qPCR) and the protein levels were evaluated by Western blot. PDGF-BB was used to simply simulate the biological characteristics of VSMCs in vitro. The effect of DLEU2 on the biological behavior of PDGF-BB-induced VSMCs was analyzed by gain- and loss-of-function assays. Bioinformatics analysis, dual luciferase reporter assay, and Pearson correlation method were conducted to determine the relationship between target genes. The role of DLEU2/miR-212-5p/ YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta) axis in PDGF-BB-induced VSMCs was verified by rescue experiments. As a result, DLEU2 and YWHAZ were up-regulated, and miR-212-5p was down-regulated in atherosclerosis serum. Overexpressed DLEU2 facilitated the biological behavior of PDGF-BB-induced VSMCs, whilst siDLEU2 did the opposite. Moreover, overexpressed DLEU2 promoted proliferating cell nuclear antigen (PCNA) expression but repressed α-smooth muscle actin (α-SMA) and Calponin expressions, while it also enhanced YWHAZ expression via suppressing miR-212-5p. MiR-212-5p mimic and siYWHAZ reversed the effects of overexpressed DLEU2 on above biological characteristics and protein expressions in PDGF-BB-induced VSMCs, while the regulatory effect of miR-212-5p mimic was partially offset by overexpressed YWHAZ. Collectively, DLEU2 modulates PDGF-BB-induced VSMC injury via miR-212-5p/YWHAZ axis in atherosclerosis.

LncRNA DLEU2 silencing impedes the migration, invasion and EMT in gastric cancer cell by suppressing PI3K/AKT signaling pathway

Context: The high expression of long non-coding RNA deleted in lymphocytic leukaemia 2 (lncRNA DLEU2) has been confirmed in gastric cancer (GC).Objective: However, the detailed mechanism concerning its involvement in GC remained unclear, which we aimed to explore in this study.Materials and methods: LncRNA DLEU2 expression in GC was estimated by bioinformatic analysis, and the relationship between the expression of DLEU2 and the clinicopathological characteristics of patients with GC was performed. qRT-PCR was employed to detect the expression of lncRNA DLEU2 and confirm the transfection efficiency following the knockdown or overexpression of DLEU2. Functional assays, including CCK-8, flow cytometry, scratching test and Transwell assays, were used to determine the role of DLEU2 in tumor phenotypes. The effects of DLEU2 on the PI3K/Akt pathway were detected by western blot. For elucidating the functions of DLEU2/PI3K/Akt axis in GC, we inhibited the PI3K/Akt pathway in rescue experiments, and evaluated the expression levels of epithelial-mesenchymal transition (EMT)-related proteins by western blot.Results: The expression of DLEU2 was aberrantly up-regulated in GC tissues and cells, which was correlated with the degree of tumor differentiation, cancer antigen 19-9 (CA19-9) and Lauren histologic classification of patients with GC. Silencing of DLEU2 induced apoptosis, attenuated viability, migration and invasion as well as inhibited the PI3K/Akt signaling pathway in GC cells. Mechanistically, the DLEU2/PI3K/Akt axis promoted the progression of GC and the EMT by down-regulating the expression of E-Cadherin and up-regulating those of N-Cadherin and Vimentin.Discussion and conclusions: LncRNA DLEU2 promoted the migration, invasion and EMT in GC by activating the PI3K/Akt pathway.

LINC00022 acts as an oncogene in colorectal cancer progression via sponging miR-375-3p to regulate FOXF1 expression

Background

Abnormal expression of long non-coding RNAs (lncRNAs) has been shown to be associated with the pathogenesis of cancers, including colorectal cancer (CRC). It has been reported that LINC00022 is highly expressed in some typs of cancer and its overexpression indicates poor prognosis. The function of LINC00022 in CRC progression remains unclear and is mainly investigated in the present study.

Methods

LINC00022 expression in CRC tissues was analyzed by using the TNMplot software. LINC00022 expression in CRC cells was measured by quantitative real-time PCR. The effects of LINC00022 on the malignant behaviors of CRC cells were detected by a series of in vitro and in vivo experiments. Dual-luciferase assays were used to verify the targeting relationship between LINC00022 and miR-375-3p and between miR-375-3p and Forkhead box F1 (FOXF1), followed by the rescue experiment.

Results

LINC00022 was highly expressed in CRC tissues compared with paired para-carcinoma tissues (n = 41). CRC cells with LINC00022 knockdown exhibited decreased cell proliferation, migration, and invasion abilities but increased apoptosis accompanied by decreased protein levels of c-Myc, cyclin D1, cleaved caspase 3, cleaved poly(ADP-ribose) polymerase, matrix metalloproteinase (MMP) 2, and MMP9. Additionally, LINC00022 downregulation in CRC cells suppressed the tube formation of human umbilical vein endothelial cells (HUVECs) as evidenced by decreased vascular endothelial growth factor A levels in LINC00022-silenced cells. The inhibitory effect of LINC00022 knockdown on tumor growth was also observed in an in vivo model. Conversely, LINC00022 overexpression showed that opposite effect. We further demonsrtaed that LINC00022 could upregulate FOXF1 expression through sponging miR-375-3p. Moreover, miR-375-3p knockdown reversed the effects of LINC00022 down-regulation.

Conclusions

LINC00022 may up-regulate FOXF1 expression via competitively binding miR-375-3p, thereby promoting the development of CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09566-5.

Obesity-Induced miR-455 Upregulation Promotes Adaptive Pancreatic β-Cell Proliferation Through the CPEB1/CDKN1B Pathway

Pancreatic β-cells adapt to compensate for increased metabolic demand during obesity. Although the miRNA pathway has an essential role in β-cell expansion, whether it is involved in adaptive proliferation is largely unknown. First, we report that EGR2 binding to the miR-455 promoter induced miR-455 upregulation in the pancreatic islets of obesity mouse models. Then, in vitro gain- or loss-of-function studies showed that miR-455 overexpression facilitated β-cell proliferation. Knockdown of miR-455 in ob/ob mice via pancreatic intraductal infusion prevented compensatory β-cell expansion. Mechanistically, our results revealed that increased miR-455 expression inhibits the expression of its target cytoplasmic polyadenylation element binding protein 1 (CPEB1), an mRNA binding protein that plays an important role in regulating insulin resistance and cell proliferation. Decreased CPEB1 expression inhibits elongation of the poly(A) tail and the subsequent translation of Cdkn1b mRNA, reducing the CDKN1B expression level and finally promoting β-cell proliferation. Taken together, our results show that the miR-455/CPEB1/CDKN1B pathway contributes to adaptive proliferation of β-cells to meet metabolic demand during obesity.

Epithelial to Mesenchymal Transition: Key Regulator of Pancreatic Ductal Adenocarcinoma Progression and Chemoresistance

Simple Summary

Pancreatic ductal adenocarcinoma’s (PDAC) dismal prognosis is associated with its aggressive biological behavior and resistance to chemotherapy. Epithelial to mesenchymal transition (EMT) has been recognized as a key driver of PDAC progression and development of drug resistance. EMT is a transient and reversible process leading to transdifferentiation of epithelial cells into a more mesenchymal phenotype. It is regulated by multiple signaling pathways that control the activity of a transcription factors network. Activation of EMT in pre-invasive stages of PDAC has been accused for early dissemination. Furthermore, it contributes to the development of intratumoral heterogeneity and drug resistance. This review summarizes the available data regarding signaling networks regulating EMT and describes the integral role of EMT in different aspects of PDAC pathogenesis.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest malignancies, characterized by aggressive biological behavior and a lack of response to currently available chemotherapy. Emerging evidence has identified epithelial to mesenchymal transition (EMT) as a key driver of PDAC progression and a central regulator in the development of drug resistance. EMT is a reversible transdifferentiation process controlled by complex interactions between multiple signaling pathways such as TGFb, Wnt, and Notch, which converge to a network of specific transcription factors. Activation of EMT transcriptional reprogramming converts cancer cells of epithelial differentiation into a more mesenchymal phenotypic state. EMT occurrence in pre-invasive pancreatic lesions has been implicated in early PDAC dissemination. Moreover, cancer cell phenotypic plasticity driven by EMT contributes to intratumoral heterogeneity and drug tolerance and is mechanistically associated with the emergence of cells exhibiting cancer stem cells (CSCs) phenotype. In this review we summarize the available data on the signaling cascades regulating EMT and the molecular isnteractions between pancreatic cancer and stromal cells that activate them. In addition, we provide a link between EMT, tumor progression, and chemoresistance in PDAC.

Dihydromyricetin Inhibits Tumor Growth and Epithelial-Mesenchymal Transition through regulating miR-455-3p in Cholangiocarcinoma

Cholangiocarcinoma (CCA) leads to poor prognosis due to high aggressiveness and common chemoresistance. Dihydromyricetin (DMY), the main bioactive compound isolated from Ampelopsis grossedentata, exhibits broad anti-tumor effects. This study aimed to investigate the inhibitory effect of DMY on CCA tumor growth and epithelial-mesenchymal transition (EMT) and its underlying mechanism in CCA. DMY treatment significantly inhibited cell proliferation and EMT in CCA cell lines. The expression of ZEB1 and vimentin were down-regulated, while the level of E-cadherin was increased after DMY treatment. By analyzing the TCGA dataset, we found that miR-455 expression was significantly downregulated, while the level of ZEB1 was up-regulated in human CCA tumor tissues compared to normal samples. Mechanistic studies showed that ZEB1 was a direct target of miR-455-3p in CCA. Moreover, DMY treatment potently increased miR-455-3p expression and inhibited ZEB1 expression. Inhibition of miR-455-3p expression abolished DMY's inhibitory effects on tumor growth and EMT in both CCA cells and cell-engrafted nude mice. Finally, DMY significantly suppressed the expressions of p-PI3K and p-AKT, while silencing miR-455-3p remarkably abrogated the inhibitory effect. In conclusion, DMY suppresses tumor growth and EMT through regulating miR-455-3p in human cholangiocarcinoma, suggesting a potential option for CCA treatment.

Emerging roles of miRNAs in the development of pancreatic cancer

Pancreatic cancer is a fatal cancer which is expected to exceed breast cancer as the third foremost source of cancer mortality by 2025. This cancer has been associated with several somatic genetic aberrations including mutations in the KRAS, CDKN2A/p16, TP53, and SMAD4. In addition, epigenetic alterations have been shown to affect development of this cancer. miRNAs are among the mostly appreciated epigenetic factors in this regard. Several oncomiRs such as miR-212, miR 506, miR-196b, miR-221-3p, miR-301a-3p, miR-23a and miR-29a have been found to promote proliferation of pancreatic cancer cells and block apoptotic pathways in these cells. On the other hand, miR-451a, miR-506, miR-142, miR-216b, miR-519d-3p, miR-1181, miR-340, miR-143-3p, miR-203a-3p, miR-455, miR-15a, miR-135a and miR-202 are among tumor suppressor miRNAs that modulate proliferation and cell cycle transition in these cells. In the current paper, we will discuss the role of oncomiRs and tumor suppressor miRNAs in the evolution of pancreatic cancer. Moreover, we will summarize the application of miRNAs as diagnostic and prognostic markers in pancreatic cancer. These studies have shown the ability of miRNAs to be served as non-invasive markers for pancreatic cancer.

The Role of Tumor-related LncRNA PART1 in cancer

BACKGROUND

As we all know, long non-coding RNA (lncRNA) affects tumor progression, which has caused a great upsurge in recent years. It can also affect the growth, migration, and invasion of tumors. When we refer to the abnormal expression of lncRNA, we will find it associated with malignant tumors. In addition, lncRNA has been proved to be a key targeted gene for the treatment of some diseases. PART1, a member of lncRNA, has been reported as a regulator in the process of tumor occurrence and development. This study aims to reveal the biological functions, specific mechanisms, and clinical significance of PART1 in various tumor cells.

METHODS

Through the careful search of PUBMED, the mechanisms of the effect of PART1 on tumorigenesis and development are summarized.

RESULTS

On the one hand, the up-regulated expression of PART1 plays a tumor-promoting role in tumors, including lung cancer, prostate cancer, bladder cancer and so on. On the other hand, PART1 is down-regulated in gastric cancer, glioma and other tumors to play a tumor inhibitory role. In addition, PART1 regulates tumor growth mainly by targeting microRNA such as miR-635, directly regulating the expression of proteins such as FUS/EZH2, affecting signal pathways such as the Toll-like receptor pathway, or regulating immune cells.

CONCLUSION

PART1 is closely related to tumors by regulating a variety of molecular mechanisms. In addition, PART1 can be used as a clinical marker for the early diagnosis of tumors and plays an important role in tumor-targeted therapy.

Long non-coding RNA DLEU2 drives EMT and glycolysis in endometrial cancer through HK2 by competitively binding with miR-455 and by modulating the EZH2/miR-181a pathway

Background

Epithelial-to-mesenchymal transition (EMT) and aerobic glycolysis are fundamental processes implicated in cancer metastasis. Although increasing evidence demonstrates an association between EMT induction and enhanced aerobic glycolysis in human cancer, the mechanisms linking these two conditions in endometrial cancer (EC) cells remain poorly defined.

Methods

We characterized the role and molecular mechanism of the glycolytic enzyme hexokinase 2 (HK2) in mediating EMT and glycolysis and investigated how long noncoding RNA DLEU2 contributes to the stimulation of EMT and glycolysis via upregulation of HK2 expression.

Results

HK2 was highly expressed in EC tissues, and its expression was associated with poor overall survival. Overexpression of HK2 effectively promoted EMT phenotypes and enhanced aerobic glycolysis in EC cells via activating FAK and its downstream ERK1/2 signaling. Moreover, microRNA-455 (miR-455) served as a tumor suppressor by directly interacting with HK2 mRNA and inhibiting its expression. Furthermore, DLEU2 displayed a significantly higher expression in EC tissues, and increased DLEU2 expression was correlated with worse overall survival. DLEU2 acted as an upstream activator for HK2-induced EMT and glycolysis in EC cells through two distinct mechanisms: (i) DLEU2 induced HK2 expression by competitively binding with miR-455, and (ii) DLEU2 also interacted with EZH2 to silence a direct inhibitor of HK2, miR-181a.

Conclusions

This study identified DLEU2 as an upstream activator of HK2-driven EMT and glycolysis in EC cells and provided significant mechanistic insights for the potential treatment of EC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02018-1.

Regulation of Hippo, TGFβ/SMAD, Wnt/β-Catenin, JAK/STAT, and NOTCH by Long Non-Coding RNAs in Pancreatic Cancer

Rapidly evolving and ever-increasing knowledge of the molecular pathophysiology of pancreatic cancer has leveraged our understanding altogether to a next level. Compared to the exciting ground-breaking discoveries related to underlying mechanisms of pancreatic cancer onset and progression, however, there had been relatively few advances in the therapeutic options available for the treatment. Since the discovery of the DNA structure as a helix which replicates semi-conservatively to pass the genetic material to the progeny, there has been conceptual refinement and continuous addition of missing pieces to complete the landscape of central dogma. Starting from transcription to translation, modern era has witnessed non-coding RNA discovery and central role of these versatile regulators in onset and progression of pancreatic cancer. Long non-coding RNAs (lncRNAs) have been shown to act as competitive endogenous RNAs through sequestration and competitive binding to myriad of microRNAs in different cancers. In this article, we set spotlight on emerging evidence of regulation of different signaling pathways (Hippo, TGFβ/SMAD, Wnt/β-Catenin, JAK/STAT and NOTCH) by lncRNAs. Conceptual refinements have enabled us to understand how lncRNAs play central role in post-translational modifications of various proteins and how lncRNAs work with epigenetic-associated machinery to transcriptionally regulate gene network in pancreatic cancer.

Long noncoding RNAs: role and contribution in pancreatic cancer

Noncoding RNAs are proclaimed to be expressed in various cancer types and one such type is found to be pancreatic ductal adenocarcinoma (PDAC). The long noncoding RNAs (LncRNAs) affect the migration, invasion, and growth of tumor cells by playing important roles in the process of epigenesis, post-transcription, and transcriptional regulation along with the maintenance of apoptosis and cell cycle. It is quite subtle whether the alterations in lncRNAs would impact PDAC progression and development. This review throws a spotlight on the lncRNAs associated with tumor functions: MALAT-1, HOTAIR, HOXA13, H19, LINC01559, LINC00460, SNHG14, SNHG16, DLX6-AS1, MSC-AS1, ABHD11-AS1, DUXAP8, DANCR, XIST, DLEU2, etc. are upregulated lncRNAs whereas GAS5, HMlincRNA717, MIAT, LINC01111, lncRNA KCNK15-AS1, etc. are downregulated lncRNAs inhibiting the invasion and progression of PDAC. These data provided helps in the assessment of lncRNAs in the development, metastasis, and occurrence of PDAC and also play a vital role in the evolution of biomarkers and therapeutic agents for the treatment of PDAC.

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.

Long non-coding RNA PART1 predicts a poor prognosis and promotes the malignant progression of pancreatic cancer by sponging miR-122

BACKGROUND AND OBJECTIVES

Long non-coding RNA (lncRNA) prostate androgen-regulated transcript 1 (PART1) was previously shown to exert an oncogenic role in several human cancers. However, whether PART1 is associated with the malignant progression of pancreatic cancer remains unclear. In the current study, we aimed to identify the role and potential mechanism of PART1 in pancreatic cancer.

METHODS

qRT-PCR was applied to detect PART1 expression in 45 cases of pancreatic cancer patients. The chi-square test was performed to assess the association between PART1 expression and clinicopathologic features, and Kaplan-Meier method was applied to evaluate overall survival. In vitro CCK-8, transwell invasion, and flow cytometry assays were applied to detect the effects of PART1 on cell proliferation, invasion, and apoptosis, respectively. Luciferase reporter and RNA immunoprecipitation assays were used to identify the regulatory mechanism between PART1 and miR-122.

RESULTS

PART1 expression was upregulated in pancreatic cancer tissues and cell lines. High PART1 expression was closely correlated with tumor size, T classification, clinical stage, and vascular invasion, and predicted a poor overall survival. PART1 knockdown significantly suppressed cell proliferation and invasion abilities of pancreatic cancer but promoted cell apoptosis. PART1 was found to serve as a molecular sponge of miR-122, and miR-122 inhibition partially reversed the inhibitory phenotypes of PART1 knockdown on pancreatic cancer cells.

CONCLUSIONS

PART1 promotes the malignant progression of pancreatic cancer by sponging miR-122. The PART1/miR-122 axis might be a promising target for anticancer therapy in patients with pancreatic cancer.

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.

LncRNA DLEU2 promotes cervical cancer cell proliferation by regulating cell cycle and NOTCH pathway

Long noncoding RNAs (lncRNAs) are known to play a crucial role in the onset and progression of cervical cancer (CC). Here, the results of RNA microarray and RNA-sequencing dataset analysis showed that lncRNA DLEU2 was significantly upregulated in CC tissues. Clinicopathologic analysis indicated that lncRNA DLEU2 was closely related to tumor topography. Functional experiments and bioinformatics analysis revealed that lncRNA DLEU2 promoted CC cell proliferation and accelerated the cell cycle. Mechanistically, lncRNA DLEU2 promoted the progression of the cell cycle and inhibited the activity of the Notch signaling pathway by inhibiting p53 expression. Additionally, lncRNA DLEU2 probably interacted with ZFP36 Ring Finger Protein (ZFP36) to inhibit the expression of p53. In conclusion, this study revealed the function of lncRNA DLEU2 in CC tumorigenesis, suggesting new therapeutic targets in CC.

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.

Exosomal long non-coding RNAs in the diagnosis and oncogenesis of pancreatic cancer

Extracellular vesicles, specifically exosomes, play a significant role as an extracellular messenger through their transporting cargo. Of particular interest are the potential roles they play in pancreatic cancer, one of the leading causes of cancer-related mortality worldwide. Pancreatic Ductal Adenocarcinoma displays high chemo-resistance and metastatic ability, which may be influenced by cancer-derived exosomes carrying proteins, lipids and RNA. To date, among the most extensively examined exosomal molecular cargo there are long non-coding RNAs (lncRNAs) that, despite the increasing interest in their role and functions, are relatively poorly understood compared to other RNA transcripts. Nevertheless, we have witnessed an increasing interest for lncRNAs roles and functions in the past decade. For example, lncRNAs have been investigated as potential biomarkers for diagnosing pancreatic cancer and may have a role as therapeutics targets for precision medicine, but may also directly intervene in tumour progression features such as metastasis, epithelial to mesenchymal transition and resistance of cancer cells towards chemotherapy agents. The function of lncRNAs within various cancer exosomes is still undefined. In this review, we summarize the current knowledge on pancreatic cancer-derived exosome specific lncRNAs having prominent roles in genome integrity, pancreatic cancer progression and in other oncogenic hallmarks.

Identification of long non-coding RNA signatures for squamous cell carcinomas and adenocarcinomas

Studies have demonstrated that both squamous cell carcinomas (SCCs) and adenocarcinomas (ACs) possess some common molecular characteristics. Evidence has accumulated to support the theory that long non-coding RNAs (lncRNAs) serve as novel biomarkers and therapeutic targets in complex diseases such as cancer.

In this study, we aimed to identify pan lncRNA signatures that are common to squamous cell carcinomas or adenocarcinomas with different tissues of origin. With the aid of elastic-net regularized regression models, a 35-lncRNA pan discriminative signature and an 11-lncRNA pan prognostic signature were identified for squamous cell carcinomas, whereas a 6-lncRNA pan discriminative signature and a 5-lncRNA pan prognostic signature were identified for adenocarcinomas. Among them, many well-known cancer relevant genes such as MALAT1 and PVT1 were included.

The identified pan lncRNA lists can help experimental biologists generate research hypotheses and adopt existing treatments for less prevalent cancers. Therefore, these signatures warrant further investigation.

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.

lncRNA DLEU2 acts as a miR-181a sponge to regulate SEPP1 and inhibit skeletal muscle differentiation and regeneration

Sarcopenia is a serious public health problem associated with the loss of muscle mass and function. The purpose of this study was to identify molecular markers and construct a ceRNA pathway as a significant predictor of sarcopenia. We designed a prediction model to select important differentially expressed mRNAs (DEMs), and constructed a sarcopenia associated ceRNA network. After correlation analysis of each element in the ceRNA network based on clinical samples and GTEX database, C2C12 mouse myoblasts were used as a model to verify the identified ceRNA pathways. A new model for predicting sarcopenia based on four molecular markers SEPP1, SV2A, GOT1, and GFOD1 was developed. The model was used to construct a ceRNA network and showed high accuracy. Correlation analysis showed that the expression levels of lncDLEU2, SEPP1, and miR-181a were closely associated with a high risk of sarcopenia. lncDLEU2 inhibits muscle differentiation and regeneration by acting as a miR-181a sponge regulating SEPP1 expression. In this study, a highly accurate prediction tool was developed to improve the prediction outcomes of sarcopenia. These findings suggest that the lncDLEU2-miR-181a-SEPP1 pathway inhibits muscle differentiation and regeneration. This pathway may be a new therapeutic target for the treatment of sarcopenia.

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.

Non-coding RNA biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.

Knockdown of LncRNA DLEU2 Inhibits Cervical Cancer Progression via Targeting miR-128-3p

Objective

Cervical cancer is one of the most common female malignancies worldwide and represents a major global health challenge. The fast growth of tumor and high rates of metastasis still lead to a poor prognosis of cervical cancer patients. It is urgent to clarify the mechanism and identify predictive biomarkers for the treatment of cervical cancer. Long non-coding RNAs (LncRNAs) have been identified in cervical cancer and are related to malignant phenotypes of cervical cancer cells. However, the roles and mechanism of LncRNA deleted in lymphocytic leukemia (DLEU2) in the tumorigenesis and progression of cervical cancer remain unknown.

Materials and Methods

qPCR was performed to analyze the expression of DLEU2, Cyclin D1, CDK4, Bax, Bcl2 and mi-128-3p. Western blot was performed to detect the cell cycle hallmarks expression. CCK8 was used to examine cell proliferation. Cellular apoptosis was analyzed by Hoechst 33,258 staining and AV/PI staining with flow cytometry. Cell cycle was analyzed by flow cytometry. The xenograft model in nude mice was used to elucidate the function of DLEU2 in vivo. Bioinformatics analysis and luciferase reporter assay were proceeded to clarify whether miR-128-3p directly binds with lncRNA DLEU2. Pull‑down assay and RNA-binding protein immunoprecipitation assay were used for exploring the relationship between DLEU2 and miR-128-3p.

Results

We demonstrated that DLEU2 was upregulated in cervical cancer tumor tissues. Downregulation of DLEU2 inhibited cell proliferation, induced apoptosis and cell cycle arrest at G2/M phase of cervical cancer cells in vitro, and suppressed tumor growth in vivo. Further, LncRNA DLEU2 is one of the targets of miR-128-3p. miR-128-3p inhibitor abrogated the cell proliferation suppressed by knockdown of DLEU2, apoptosis induced by knockdown of DLEU2 and reversed the expression of cell cycle hallmarks regulated by knockdown of DLEU2.

Conclusion

Taken together, these results suggested knockdown of DLEU2 inhibited cervical cancer progression via targeting miR-128-3p.

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.

Identification of microRNA expression signature for the diagnosis and prognosis of cervical squamous cell carcinoma

Cervical cancer is the fourth leading cause of cancer death among women globally. The prognosis of cervical cancer patients differs considerably, and clinical outcomes are difficult to predict. Given the significant roles of miRNAs in human cancers, identification of novel and reliable miRNA biomarkers is important for targeted cervical cancer therapy. In the present study, we aimed to reveal biological significance of miR-200a, miR-423, miR-34a, miR-193a, and miR-455 for the prognosis and diagnosis of cervical cancer and their association with the clinical outcomes of patients. Distinct expression profiles of miRNAs in formalin-fixed paraffin-embedded tissue samples of patients and healthy controls were evaluated using qRT-PCR. We identified miR-200a, miR-455, and miR-34a were significantly downregulated in cervical squamous cell carcinoma tissues compared to normal cervix tissue from healthy controls. Both miR-455 and miR-34a confer a promising diagnostic factor for the cervical cancer while miR-200a showed no significance in ROC analysis. Notably, low expression of miR-34a was markedly associated with the poor overall survival of cervical cancer patients as revealed by Kaplan-Meier survival analysis. Also, univariate and multivariate analysis indicated miR-34a expression as an independent prognostic factor. Consequently, our results underline the importance of distinct expression miRNAs in cervical squamous cell carcinoma.

Identification of aberrantly expressed long non-coding RNAs in ovarian high-grade serous carcinoma cells

PURPOSE

To identify the aberrantly expressed long non-coding RNAs (lncRNAs) in ovarian high-grade serous carcinoma (HGSC).

METHODS

Total RNA was isolated in HGSC cell lines, ovarian surface epithelial cells, and normal ovaries. Aberrantly expressed lncRNAs in HGSC were identified by PCR array, which analyzes 84 kinds of lncRNAs. To infer their functions, HGSC cell lines with different levels of expression of the identified lncRNAs were established, and then, activities of proliferation, migration, and apoptosis were examined. Expression levels of the identified lncRNAs were also examined in multiple ovarian HGSC tissues.

RESULTS

Ten aberrantly expressed lncRNAs, six upregulated and four downregulated, were identified in the HGSC cell lines. The authors established four HGSC cell lines: in two of the cell lines, one of the upregulated lncRNAs was knocked down, and in two other cell lines, one of the downregulated lncRNAs (MEG3 and POU5F1P5) was overexpressed. Migration activities were inhibited in the HGSC cell lines overexpressing MEG3 or POU5F1P5 while there were no differences in proliferation and apoptosis between the established and control cell lines. The four lncRNAs downregulated in the HGSC cell lines were also observed to be downregulated in ovarian HGSC tissues.

CONCLUSION

The authors identified four downregulated lncRNAs in ovarian HGSC.

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.

LncRNA DLEU2 promotes tumour growth by sponging miR-337-3p in human osteosarcoma

According to statistics, abnormal regulation of lncRNAs pivotally influences multiple malignant tumours. DLEU2, as one of these lncRNAs, is detected to be related to growth and development of tumours. The molecular mechanisms of DLEU2 in osteosarcoma, however, are still unknown. QRT-PCR was adopted to analyse the correlations of clinicopathological features and prognosis of osteosarcoma cases with DLEU2. The influences of DLEU2 on cell migration and viability were evaluated independently by experiments in vitro and in vivo. Bioinformatics analysis, RNA immunoprecipitation (RIP) assay, and dual luciferase reporter gene assay confirmed the specific binding of DLEU2 to miR-337-3p. Moreover, rescue experiments were carried out to further evaluate the regulatory association between miR-337-3p expression and DLEU2. In osteosarcoma tissues and cells, DLEU2 expression level was raised remarkably in comparison with that in para-carcinoma normal tissues, and DLEU2 high expression had associations with poor prognosis, tumour stages, and TS of osteosarcoma cases. Cell migration ability and viability were blocked by DLEU2 knockdown but enhanced by ectopic DLEU2 expression in vitro and in vivo. Additionally, DLEU2 was found to sponge miR-337-3p and trigger the stimulating effect in osteosarcoma cells, which would be suppressed by miR-337-3p mimics. Furthermore, a negative correlation existed between miR-337-3p expression and DLEU2 in osteosarcoma tissues. This study manifests that DLEU2 sponges miR-337-3p to accelerate tumour growth and is confirmed to be a factor for poor prognosis of osteosarcoma cases. SIGNIFICANCE OF THE STUDY: LncRNA DLEU2 has been reported to be dysregulated in many tumours; however, the functions and underlying mechanism of DLEU2 in osteosarcoma pathogenesis are still unknown. This study is the first to demonstrate the roles of DLEU2 in osteosarcoma and revealed that DLEU2 may serve as a ceRNA to sponge miR-337-3p and then promote the progression of osteosarcoma, providing a potential therapeutic target for osteosarcoma.

The multifaceted roles of long noncoding RNAs in pancreatic cancer: an update on what we know

Pancreatic cancer (PC) is one of the leading causes of cancer-related deaths worldwide. Due to the shortage of effective biomarkers for predicting survival and diagnosing PC, the underlying mechanism is still intensively investigated but poorly understood. Long noncoding RNAs (lncRNAs) provide biological functional diversity and complexity in protein regulatory networks. Scientific studies have revealed the emerging functions and regulatory roles of lncRNAs in PC behaviors. It is worth noting that some in-depth studies have revealed that lncRNAs are significantly associated with the initiation and progression of PC. As lncRNAs have good properties for both diagnostic and prognostic prediction due to their translation potential, we herein address the current understanding of the multifaceted roles of lncRNAs as regulators in the molecular mechanism of PC. We also discuss the possibility of using lncRNAs as survival biomarkers and their contributions to the development of targeted therapies based on the literature. The present review, based on what we know about current research findings, may help us better understand the roles of lncRNAs in PC.

LINC01232 exerts oncogenic activities in pancreatic adenocarcinoma via regulation of TM9SF2

Pancreatic adenocarcinoma (PAAD), one of the most prevailing malignant tumors in digestive system, is identified as one of the main culprits of cancer-associated mortality. Despite long intergenic non-protein coding RNA 1232 (LINC01232) is found to be upregulated in TCGA PAAD tissues and associated with poor prognosis, the potential of LINC01232 in PAAD progression still needs more explorations. In this study, LINC01232 was chosen to be the research object in PAAD cellular processes. Functionally, loss-of function assays were carried out and the experimental results indicated that suppression of LINC01232 hindered the deterioration of PAAD by affecting cell proliferation and migration. Furthermore, relationship between LINC01232 and its nearby gene transmembrane 9 superfamily member 2 (TM9SF2) was investigated. The same expression pattern of TM9SF2 in TCGA PAAD samples was observed. It was found that upregulation of LINC01232 could be a crucial factor for the dysregulation of TM9SF2. Mechanistically, LINC01232 recruited EIF4A3 to boost TM9SF2 mRNA stability. Besides, our findings demonstrated that the transcriptional activation of LINC01232 and TM9SF2 was mediated by SP1. Therefore, we concluded that LINC01232 executed carcinogenic properties in PAAD progression via regulation of TM9SF2. In conclusion, this study was the first to unveil the role and molecular mechanism of LINC01232, suggesting LINC01232 as a promising molecular target for pancreatic cancer treatment.

Long Non-Coding RNA in the Pathogenesis of Cancers

The incidence and mortality rate of cancer has been quickly increasing in the past decades. At present, cancer has become the leading cause of death worldwide. Most of the cancers cannot be effectively diagnosed at the early stage. Although there are multiple therapeutic treatments, including surgery, radiotherapy, chemotherapy, and targeted drugs, their effectiveness is still limited. The overall survival rate of malignant cancers is still low. It is necessary to further study the mechanisms for malignant cancers, and explore new biomarkers and targets that are more sensitive and effective for early diagnosis, treatment, and prognosis of cancers than traditional biomarkers and methods. Long non-coding RNAs (lncRNAs) are a class of RNA transcripts with a length greater than 200 nucleotides. Generally, lncRNAs are not capable of encoding proteins or peptides. LncRNAs exert diverse biological functions by regulating gene expressions and functions at transcriptional, translational, and post-translational levels. In the past decade, it has been demonstrated that the dysregulated lncRNA profile is widely involved in the pathogenesis of many diseases, including cancer, metabolic disorders, and cardiovascular diseases. In particular, lncRNAs have been revealed to play an important role in tumor growth and metastasis. Many lncRNAs have been shown to be potential biomarkers and targets for the diagnosis and treatment of cancers. This review aims to briefly discuss the latest findings regarding the roles and mechanisms of some important lncRNAs in the pathogenesis of certain malignant cancers, including lung, breast, liver, and colorectal cancers, as well as hematological malignancies and neuroblastoma.

Silencing of DLEU2 suppresses pancreatic cancer cell proliferation and invasion by upregulating microRNA-455

Long noncoding RNA (lncRNA) DLEU2 has been shown to be dysregulated in several type of tumor. However, the potential biological roles and molecular mechanisms of DLEU2 in pancreatic cancer (PC) progression are poorly understood. In this study, we found that the DLEU2 level was substantially upregulated in PC tissues and PC cell lines, and significantly associated with poor clinical outcomes in PC patients. Overexpression of DLEU2 significantly induced PC cell proliferation and invasion, whereas knockdown of DLEU2 impaired cell proliferation and invasion in vitro. Furthermore, bioinformatics analysis, luciferase reporter assay, and RNA immunoprecipitation assay revealed that DLEU2 directly bond to microRNA‐455 (miR‐455) and functioned as an endogenous sponge for miR‐455, which could remarkably suppress cell growth and invasion. We also determined that SMAD2 was a direct target of miR‐455, and the restoration of SMAD2 rescued cell growth and invasion that were reduced by DLEU2 knockdown or miR‐455 overexpression. In addition, low miR‐455 expression and high SMAD2 expression was correlated with poor patient survival. These results indicate that DLEU2 is an important promoter of PC development, and targeting the DLEU2/miR‐455/SMAD2 pathway could be a promising therapeutic approach in the treatment of PC.