Deleted In Lymphocytic Leukemia 1 Research Articles

Long non-coding RNA DLEU1 promotes malignancy of breast cancer by acting as an indispensable coactivator for HIF-1α-induced transcription of CKAP2

Earlier studies have suggested deleted in lymphocytic leukemia 1 (DLEU1), a long non-coding RNA, is a prognostic biomarker for breast cancer. Here we explored the malignant behaviors and underlying mechanisms regulated by DLEU1 in breast cancer. We demonstrated that up-regulation of DLEU1 was detected in breast cancer tissues and cells, particularly in tumors of higher malignancy. DLEU1 knockdown inhibited the growth and the motility of breast cancer cells. Mechanistically, DLEU1 interacted with HIF-1α to collectively activate the transcription of CKAP2. By activating ERK and STAT3 signaling, CKAP2 essentially mediated the pro-tumor activities of DLEU1. In vivo, depletion of DLEU1 inhibited xenograft growth and metastasis of breast cancer cells. Therefore, DLEU1, by acting as a coactivator for HIF-1α, up-regulates CKAP2 expression and promotes malignancy of breast cancer. Targeting DLEU1, HIF-1α, or CKAP2 may thus benefit breast cancer treatment.

Survival‑related DLEU1 is associated with HPV infection status and serves as a biomarker in HPV‑infected cervical cancer.

Human papillomavirus (HPV) is the most common risk factor for the occurrence of cervical cancer (CC). In recent years, the important roles of long non-coding RNAs (lncRNAs) in CC have emerged, but studies on the relationship between lncRNAs and HPV-positive (HPV+) CC remain scarce. The present study aimed to investigate whether lncRNA deleted in lymphocytic leukemia 1 (DLEU1) is associated with HPV infection and explore the clinical significance of DLEU1 in HPV+ patients with CC. DLEU1 expression was detected by reverse transcription-quantitative PCR. The ability of DLEU1 to screen patients with CC from controls and differentiate individuals with different HPV infection status was evaluated by receiver operating characteristic analysis. The association of DLEU1 with the survival prognosis of patients with CC was assessed by Kaplan-Meier survival analysis and Cox regression analysis. The RNA Interactome Database was used to predict molecules interacting with DLEU1. The results indicated that DLEU1 expression was significantly upregulated in CC tissues and cell lines, particularly in those that were HPV+. In addition, DLEU1 had a high diagnostic value in discriminating patients with CC and differentiating between HPV+ and HPV- patients with CC, and had a certain ability to screen HPV+ controls. DLEU1 was correlated with HPV infection in CC patients. Furthermore, DLEU1 was indicated to be associated with survival prognosis in both total patients with CC and HPV+ patients with CC, and independently predict the prognosis of patients with CC. Most of the molecules interacting with DLEU1 were microRNAs. In conclusion, abnormal DLEU1 expression is associated with HPV infection and may serve as a diagnostic and prognostic biomarker for HPV+ patients with CC.

Overexpression of lncRNA DLEU1 in Gastric Cancer Tissues Compared to Adjacent Non-Tumor Tissues.

Gastric cancer (GC) is caused by environmental factors and genetic changes of protein-coding- and non-coding sequences, which entail short non-coding RNAs (microRNAs) and long non-coding RNAs (lncRNAs). DLEU1 (deleted in lymphocytic leukemia 1), as an effective lncRNA located on chromosome 14.3q 13, modulates the nuclear factor-kB (NF-kB) signaling pathway. This gene usually plays an oncogenic role in the tumorigenesis of multiple types of cancer. The present study examined the expression level of DLEU1 and its association with clinical-pathological characteristics in GC. Total RNA of 100 specimens was extracted by TRIzol reagent. After cDNA synthesis, qRT-PCR analysis was performed to measure the expression level of the DLEU1 gene and the obtained data were analyzed by SPSS 16.0. The relative expression level of DLEU1 significantly increased in tumor specimens compared to the normal tumor margin specimens. The biomarker index of lncRNA DLEU1 was 0.7 in tumor tissues. The observed high expression level of DLEU1 was pertinent to the pathological progressive TNM stage, lymph node metastasis, differentiation degree, patient's age and lifestyle, and Helicobacter pylori infection in GC patients. The obtained findings suggested that DLEU1 acts as an oncogene in GC and might be a new target for gene therapy of GC.

DLEU1 promotes oral squamous cell carcinoma progression by activating interferon-stimulated genes

Long noncoding RNAs (lncRNAs) are deeply involved in cancer development. We previously reported that DLEU1 (deleted in lymphocytic leukemia 1) is one of the lncRNAs overexpressed in oral squamous cell carcinoma (OSCC) cells, where it exhibits oncogenic activity. In the present study, we further clarified the molecular function of DLEU1 in the pathogenesis of OSCC. Chromatin immunoprecipitation-sequencing (ChIP-seq) analysis revealed that DLEU1 knockdown induced significant changes in the levels of histone H3 lysine 4 trimethylation (H3K4me3) and H3K27 acetylation (H3K27ac) in OSCC cells. Notably, DLEU1 knockdown suppressed levels of H3K4me3/ H3K27ac and expression of a number of interferon-stimulated genes (ISGs), including IFIT1, IFI6 and OAS1, while ectopic DLEU1 expression activated these genes. Western blot analysis and reporter assays suggested that DLEU1 upregulates ISGs through activation of JAK-STAT signaling in OSCC cells. Moreover, IFITM1, one of the ISGs induced by DLUE1, was frequently overexpressed in primary OSCC tumors, and its knockdown inhibited OSCC cell proliferation, migration and invasion. These findings suggest that DLEU1 exerts its oncogenic effects, at least in part, through activation of a series ISGs in OSCC cells.

Knockdown of lncRNA DLEU1 inhibits the tumorigenesis of oral squamous cell carcinoma via regulation of miR‑149‑5p/CDK6 axis.

Oral squamous cell carcinoma (OSCC) is a frequent malignant tumor worldwide. Long non-coding RNAs (lncRNAs) are known to play key roles in different types of cancer, including OSCC. It was previously reported that lncRNA deleted in lymphocytic leukemia 1 (DLEU1) is notably upregulated in OSCC; however, the role of DLEU1 in OSCC remains unclear. Gene and protein expression levels in OSCC cells were detected by reverse transcription-quantitative PCR and western blotting, respectively, in the present study. A Transwell assay was performed to measure cell migration and invasion. Flow cytometry was used to detect cell apoptosis, and the dual-luciferase reporter assay was applied to confirm the interaction between DLEU1, microRNA (miR)-149-5p and CDK6 in OSCC cells. DLEU1 expression was negatively associated with the survival rate of patients with OSCC. In addition, silencing of DLEU1 notably inhibited the proliferation of OSCC cells by inducing apoptosis. Meanwhile, DLEU1 directly bound to miR-149-5p, and CDK6 was found to be the direct target of miR-149-5p. Furthermore, DLEU1 knockdown-induced inhibition of OSCC cell proliferation was significantly reversed by the miR-149-5p antagomir. Knockdown of lncRNA DLEU1 reversed the proliferation of OSCC cells via regulation of the miR-149-5p/CDK6 axis. Thus, DLEU1 may serve as a novel target for treating OSCC.

Deleted in lymphocytic leukemia 1 promoted proliferation and apoptosis of nephroblastoma cells through regulating miR-513a-5p and RANBP2 pathway

Objective: To study the regulatory effects and mechanisms of deleted in lymphocytic leukemia 1 (DLEU1), microRNA-513a-5p (miR-513a-5p), and RAN binding protein 2 (RANBP2) in nephroblastoma. Methods: The GHINK-1 cells were transfected with pcDNA (pcDNA group), pcDNA-DLEU1 (pcDNA-DLEU1 group), miR-NC (miR-NC group), miR-513a-5p mimics (miR-513a-5p group), pcDNA-RANBP2 (pcDNA-RANBP2 group), pcDNA-DLEU1 and miR-NC (pcDNA-DLEU1+ miR-NC group), pcDNA-DLEU1 and miR-513a-5p mimics (pcDNA-DLEU1+ miR-513a-5p group), miR-513a-5p mimics and pcDNA (miR-513a-5p+ pcDNA group), miR-513a-5p mimics and pcDNA-RANBP2 (miR-513a-5p + pcDNA-RANBP2 group). Real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) was used to detect the expressions of DLEU1, miR-513a-5p, RANBP2 in nephroblastoma tissues, normal adjacent tissues, normal kidney cell HK2, and hemangioblastoma cell GHINK-1. Western blot was used to detect the expressions of proliferating cell nuclear antigen (PCNA), B cell lymphoma/leukemia-2 (Bcl-2) and Bcl-2 related X (Bax). Cell counting kit 8 (CCK-8) was used to detect the cell survival rate. Flow cytometry was used to detect the apoptosis rate. Dual luciferase report test was used to detect the luciferase activity of cells. Results: The expression levels of DLEU1, miR-513a-5p and RANBP2 in adjacent tissues were 1.02±0.08, 1.01±0.06, 1.00±0.05, respectively, significantly lower than 5.16±0.24, 0.23±0.02, 1.67±0.09 in nephroblasts tumor tissues (P<0.05). Their expression levels in HK2 cells were 1.00±0.06, 1.00±0.08, 1.02±0.09, respectively, significantly lower than 3.15±0.21, 0.18±0.01, 1.54±0.10 in GHINK-1 cells (P<0.05). Overexpression of DLEU1 significantly reduced the apoptosis rate (7.35±0.41 vs 12.35±1.12, P<0.05). Overexpression of RANBP2 significantly reduced the apoptosis rate (8.89±0.48 vs 12.64±1.12, P<0.05). Compared with the miR-NC group (1.01±0.06, 0.99±0.06), the luciferase activity of DLEU1-WT (0.43±0.04) and RANBP2-WT (0.61±0.07) in miR-513a-5p group were significantly reduced (P<0.05). Compared with anti-miR-NC group (0.99±0.07, 0.98±0.05), the luciferase activity of DLEU1-WT (1.34±0.11) and RANBP2-WT (1.39 ±0.13) in anti-miR-513a-5p group was significantly increased (P<0.05). Simultaneous overexpression of pcDNA-DLEU1 and miR-513a-5p in GHINK-1 cells significantly reduced the apoptosis rate (11.34±1.03 vs 8.51±0.69, P<0.05). Simultaneous overexpression of miR-513a-5p and RANBP2 in GHINK-1 cells significantly reduced the apoptosis rate (9.96±0.72 vs 15.94±1.00, P<0.05). Conclusions: The long-chain non-coding RNA (lncRNA) DLEU1 can promote the proliferation and inhibit the apoptosis of nephroblastoma cells. The mechanism is related to the targeted regulation of miR-513a-5p and RANBP2 function, which will provide theoretical support for the nephroblastoma treatment.

Long non-coding RNA DLEUI promotes papillary thyroid carcinoma progression by sponging miR-421 and increasing ROCK1 expression.

We investigated the role of long non-coding RNA DLEU1 (deleted in lymphocytic leukemia 1) in the progression of papillary thyroid carcinoma (PTC). DLEU1 levels were higher in PTC cell lines (BHP5-16, TPC-1,8505C, and SW1736) and patient tissues (n=54) than in a human thyroid follicular epithelial cell line (Nthy-ori3-1) or adjacent normal thyroid tissues. High DLEU1 expression correlated positively with lymph node metastasis and advanced clinical stages in PTC patients. Bioinformatics, dual luciferase reporter, and RNA pulldown assays confirmed that DLEU1 directly binds to miR-421. Moreover, bioinformatics and dual luciferase reporter assays showed that miR-421 directly binds to the 3’untranslated region of the rho-related coiled-coil kinase 1 (ROCK1) in TPC-1 cells. PTC patient tissues and cell lines showed high ROCK1 mRNA and protein levels as well as low miR-421 levels. CCK-8, flow cytometry, wound healing, and Transwell invasion assays demonstrated that DLEU1 silencing decreases TPC-1 cell proliferation, survival and progression, but they can be rescued by miR-421 knockdown or ROCK1 overexpression. DLEU1 knockdown in TPC-1 cells decreased in vivo xenograft tumor size and weight compared to controls in nude mice. These findings demonstrate that DLEU1 promotes PTC progression by sponging miR-421 and increasing ROCK1 expression.

Exosomal-lncRNA DLEU1 Accelerates the Proliferation, Migration, and Invasion of Endometrial Carcinoma Cells by Regulating microRNA-E2F3.

PurposeLong non-coding RNAs (lncRNAs) may act as oncogenes in several cancers, including endometrial carcinoma (EC). The purpose of the current study is to investigate the regulatory mechanism of exosomal-lncRNA deleted in lymphocytic leukemia1 (DLEU1) on EC.MethodsThe expression levels of lncRNA DLEU1, microRNA-381-3p and E2F Transcription Factor 3 (E2F3) in EC tissues or cells were detected using quantitative reverse transcription–polymerase chain reaction (qRT-PCR). We then analysed the proliferation, migration, and invasion of EC cells by performing the MTT assay, wound healing assay, and transwell invasion assay, respectively. Identification of exosomes was detected using Western blot assay. The uptake of exosomes was detected by a confocal microscope. The effects of exosomes on EC cells were investigated by construction of cell co-culture system. The interactions among DLEU1, miR-381-3p and E2F3 were confirmed using the dual-luciferase reporter (DLR) assay.ResultsLncRNA DLEU1 expression was highly up-regulated in EC tissues and cells. Knockdown of DLEU1 inhibited the proliferation, migration, and invasion of EC cells. Exosomes could be uptaken by the ambient EC cells. MiR-381-3p was a target of DLEU1 and was negatively modulated by DLEU1. Overexpression of miR-381-3p suppressed the proliferation, migration, and invasion of EC cells. Additionally, E2F3 was the target gene of miR-381-3p and was negatively modulated by miR-381-3p. Upregulation of miR-381-3p and down-regulation of E2F3 reversed the promoting effect of exosomal DLEU1 on EC cells.ConclusionExosomal DLEU1 accelerates the development of EC by regulating the miR-381-3p/E2F3 axis, thus DLEU1 may act as a possible therapeutic target for treating EC.

Upregulation of Serum lncRNA DLEU1 Predicts Progression of Premalignant Endometrial Lesion and Unfavorable Clinical Outcome of Endometrial Cancer.

Objective:Long non-coding RNAs (lncRNAs) play a critical role in tumorigenesis. Upregulation of lncRNA deleted in lymphocytic leukemia 1 (DLEU1) has been reported in endometrial cancer (EC) tissues. This prospective study aimed to determine the potential clinical significance of serum lncRNA DLEU1 in EC.Methods:The serum lncRNA DLEU1 level was detected in EC patients, patients with endometrial hyperplasia and healthy controls by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Then its clinical value in EC was further evaluated.Results:Our results demonstrated that serum lncRNA DLEU1 levels were significantly increased in patients with EC, and serum lncRNA DLEU1 showed good performance for discriminating EC patients from patients with endometrial hyperplasia and healthy controls. In addition, EC patients with advanced clinicopathological features had higher circulating lncRNA DLEU1 level than those with favorable clinical characteristics. Moreover, EC patients in the high serum lncRNA DLEU1 group suffered worse overall survival and disease-free survival than those in the low serum lncRNA DLEU1 group. Furthermore, multivariate cox regression analysis displayed that the serum lncRNA DLEU1 served as an independent prognostic factor for EC.Conclusions:Collectively, our study suggests that serum lncRNA DLEU1 is a novel and promising biomarker for prognostic estimation of EC.

SP1-DLEU1-miR-4429 feedback loop promotes cell proliferative and anti-apoptotic abilities in human glioblastoma.

Mounting studies have revealed that long non-coding RNA (lncRNA) deleted in lymphocytic leukemia 1 (DLEU1) positively regulated the initiation and development of various human malignant tumors. Nevertheless, the function and mechanism of DLEU1 in human glioblastoma multiforme (GBM) remain elusive and ill-defined. The current study was designed to highlight the functional role and disclose the underlying molecular mechanism by which DLEU1 regulated GBM development. We found that DLEU1 was up-regulated in GBM and DLEU1 knockdown significantly inhibited GBM cell proliferation and induced apoptosis. As predicted by bioinformatics analysis and validated in mechanistic assays, SP1 could bind to the promoter region of DLEU1 to activate DLEU1 transcription. Additionally, miR-4429 was verified as a target gene of DLEU1 and negatively modulated by DLEU1. More importantly, miR-4429 overexpression repressed the mRNA and protein levels of SP1 via binding to the 3′UTR of SP1. Overexpression of SP1 or miR-4429 inhibitor could partly abolish the effect of DLEU1 knockdown on cell viability and apoptosis in GBM. Accordingly, our experimental data revealed that SP1–DLEU1–miR-4429 formed a feedback loop to promote GBM development, providing a new evidence for the role of DLEU1 in GBM.

LncRNA DLEU1/microRNA-300/RAB22A axis regulates migration and invasion of breast cancer cells.

To explore the possible role of deleted in lymphocytic leukemia 1 (DLEU1) in regulating the metastasis of breast cancer and its underlying mechanism. The expression levels of DLEU1 in 60 cases of breast cancer tissues and adjacent normal tissues were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Survival analysis and receiver operating characteristic (ROC) curves were introduced to analyze the correlation between DLEU1 expression and the clinical features of enrolled breast cancer patients. After altering expressions of DLEU1, RAB22A or microRNA-300 by plasmid transfection, the abilities of breast cancer cells to migrate and invade were evaluated by transwell assay. Western blot was conducted to detect protein level changes of epithelial-mesenchymal transition (EMT)-related genes regulated by DLEU1, RAB22A or microRNA-300. Dual-luciferase reporter gene assay was performed to detect the binding relation between microRNA-300 with DLEU1 and RAB22A. DLEU1 expression remains higher in breast cancer tissues than in normal adjacent tissues, and has a certain diagnostic value. The overall survival of breast cancer patients was negatively correlated with DLEU1 expression. Overexpression of DLEU1 or RAB22A, or microRNA-300 knockdown could enhance the migratory and invasive capacities, as well as increase EMT ofBT549 cells. On the contrary, knockdown of DLEU1 or RAB22A, or microRNA-300 overexpression in MCF-7 cells obtained the opposite trends of cellular behaviors. Dual-luciferase reporter gene assay confirmed that DLEU1 and RAB22A could bind to microRNA-300. Further verification showed that RAB22A expression was positively regulated by DLEU1, but negatively regulated by microRNA-300. Finally, we found that DLEU1 overexpression could reverse the inhibitory effects of microRNA-300 on proliferation, migration, and EMT of breast cancer cells. DLEU1 is highly expressed in breast cancer, which promotes migration, invasion, and EMT of breast cancer cells by targeting microRNA-300 to mediate RAB22A.

Knockdown of long noncoding RNA DLEU1 suppresses the progression of renal cell carcinoma by downregulating the Akt pathway.

Increasing evidence has indicated that long noncoding RNAs (lncRNAs) are involved in the tumorigenesis and progression of various types of cancer. The lncRNA deleted in lymphocytic leukemia 1 (DLEU1) has been reported to be dysregulated in cancer cells and thus associated with tumor development; however, the role of DLEU1 in renal cell carcinoma (RCC) remains unclear. In the present study, DLEU1 was knocked down using small interfering RNA in the RCC cell lines KETR3 and 786-O to determine the role of DLEU1. Cell Counting Kit-8, colony formation, Transwell and flow cytometry assays were performed to assess the effects of DLEU1 on cell proliferation, migration, invasion and apoptosis in KETR3 and 786-O cells. The protein expression levels of factors associated with apoptosis and epithelial-mesenchymal transition (EMT) were examined by western blot. The results demonstrated that silencing DLEU1 decreased the growth capacity, migration and invasion of KETR3 and 786-O cells. Additionally, loss of DLEU1 was observed to stimulate the mitochondrial pathway of cell apoptosis via regulation of the expression of Bcl-2/Bax, cleaved caspase-3 and cleaved caspase-9 in KETR3 and 786-O cells. Furthermore, DLEU1 knockdown significantly inhibited the protein kinase B (Akt) pathway by downregulating the expression of phosphorylated-Akt, cyclin D1 and P70S6 kinase. In addition, depletion of DLEU1 was observed to impair the process of EMT in RCC cells via the upregulation of E-cadherin, and downregulation of N-cadherin and vimentin. Collectively, these results indicated a pro-oncogenic role of DLEU1 in the progression and development of RCC via modulation of the Akt pathway and EMT phenotype.

Long noncoding RNA DLEU1 aggravates glioma progression via the miR-421/MEF2D axis.

BackgroundLong noncoding RNA (lncRNA) deleted in lymphocytic leukemia 1 (DLEU1) was reported to be involved in the development and progression of multiple cancers. However, the accurate expression pattern, biological function and potential molecular mechanism of DLEU1 in glioma are not yet known. The present study investigated the role of DLEU in the development and progression of glioma, as well as the potential mechanism played by DLEU1 in glioma.Materials and methodsThe levels of DLEUI in glioma tissues and cell lines were examined using quantitative real-time PCR. The potential effects of DLEU1 on the proliferation, mobility, invasion and apoptosis of glioma cells were evaluated using corresponding in vitro experiments. The association between DLEU1 and microRNA (miR)-421 was also determined using luciferase reporter activity and RNA immunoprecipitation (RIP) assays.ResultsThe results revealed that DLEU1 was significantly upregulated in glioma tissues and cell lines. Increased DLEU1 was positively associated with the high-grade carcinoma (III–IV). Functional studies revealed that knockdown of DLEU1 expression by siRNA led to decreased proliferation, migration and invasion and increased apoptosis in human glioma cells. Furthermore, luciferase reporter activity and RIP assays confirmed that DLEUI could act as a competing endogenous RNA (ceRNA) for miR-421 that functioned as a tumor suppressor in glioma. Moreover, inhibition miR-421 partially restored the effect of DLEU1 knockdown on the glioma cells. DLEU1 could regulate myocyte enhancer factor 2D (MEF2D) expression, a known target of miR-421 in glioma cells.ConclusionTaken together, these findings suggested that DLEU1 regulated MEF2D expression to promote glioma progression by sponging miR-421 and that DLEU1 might be a potential therapeutic target for glioma.

Long non‑coding RNA DLEU1 promotes cell proliferation of glioblastoma multiforme.

Glioblastoma multiforme (GBM) is the most common malignant tumor with high morbidity and mortality. This study investigated the role of long non‑coding RNAs (lncRNAs) in glioblastomagenesis progression. Using the GSE2223 and GSE59612 datasets, and RNA sequencing data of GBM from The Cancer Genome Atlas, differentially expressed (DE) genes including DE messenger RNAs (DEmRNAs) and DElncRNAs between GBM and normal controls were identified. Based on the competing endogenous RNA hypothesis, DElncRNA‑micro RNA (miRNA)‑DEmRNA interactions were obtained by target gene prediction. Gene Ontology (GO) and Kyoto Encyclopedia of Gene and Genomes pathway analysis of DEmRNAs in the DElncRNA‑miRNA‑DEmRNA network was performed. Expression and function analyses of DElncRNAs were performed by reverse transcription‑polymerase chain reaction (RT‑PCR) and an established viability assay, respectively. In total, 712 DE genes were identified. Significant upregulation of lncRNA deleted in lymphocytic leukemia 1 (DLEU1) was revealed in GBM and a number of other types of cancer. DLEU1 interacted with 315 miRNAs and 105 DEmRNAs. The DEmRNAs were mainly enriched in tumorigenesis‑associated GO terms (angiogenesis, positive regulation of cell proliferation, positive regulation of fibroblast apoptotic processes and regulation of neutrophil migration) and pathways (Hippo signaling pathway, cancer pathways, and Wnt signaling pathway). Correlation analysis revealed that mRNA TNF receptor associated factor 4 (TRAF4) was associated with DLEU1 expression. RT‑PCR demonstrated that the expression levels of DLEU1 and TRAF4 were increased in GBM tissues. Small interfering RNA demonstrated that silencing DLEU1 downregulated TRAF4. The viability of GBM cells was significantly decreased following RNA interference with DLEU1 and TRAF4 production. The results demonstrate that DLEU1 and TRAF4 is highly expressed in GBM tissues and promotes proliferation of GBM cells. It may act as a competing endogenous RNA and influence tumorigenesis of GBM.

Long noncoding RNA DLEU1 aggravates pancreatic ductal adenocarcinoma carcinogenesis via the miR-381/CXCR4 axis.

Recent evidence has highlighted that long noncoding RNAs (lncRNA) are associated with many diseases, particularly cancer. However, current understanding of the lncRNA deleted in lymphocytic leukemia 1 (DLEU1) in pancreatic ductal adenocarcinoma (PDAC) remains limited. Our studies indicated that the DLEU1 expression level was upregulated in PDAC tissue samples compared with adjacent normal tissue. Moreover, the aberrant overexpression of DLEU1 indicated poor prognosis of patients with PDAC. Loss-of-function experiments revealed that DLEU1 knockdown inhibited the proliferation, migration, and invasion of PDAC cells in vitro and decreased tumor growth in vivo. Bioinformatics analysis predicted that miR-381 potentially targeted the DLEU1 3'-untranslated region (UTR), suggesting an interaction between miR-381 and DLEU1. Furthermore, miR-381 also targeted the chemokine receptor-4 (CXCR4) messenger RNA 3'-UTR, which was validated by luciferase reporter assay. Taken together, our study demonstrated the oncogenic role of DLEU1 in clinical PDAC specimens and cellular experiments, showing the potential involvement of DLEU1/miR-381/CXCR4 pathway. These results provide novel insight into PDAC tumorigenesis.

Screening for long noncoding RNAs associated with oral squamous cell carcinoma reveals the potentially oncogenic actions of DLEU1

Recent studies have shown that long noncoding RNAs (lncRNAs) have pivotal roles in human malignancies, although their significance in oral squamous cell carcinoma (OSCC) is not fully understood. In the present study, we identified lncRNAs functionally associated with OSCC. By analyzing RNA-seq datasets obtained from primary head and neck squamous cell carcinoma (HNSCC), we identified 15 lncRNAs aberrantly expressed in cancer tissues. We then validated their expression in 18 OSCC cell lines using qRT-PCR and identified 6 lncRNAs frequently overexpressed in OSCC. Among those, we found that knocking down DLEU1 (deleted in lymphocytic leukemia 1) strongly suppressed OSCC cell proliferation. DLEU1 knockdown also suppressed migration, invasion, and xenograft formation by OSCC cells, which is suggestive of its oncogenic functionality. Microarray analysis revealed that DLEU1 knockdown significantly affects expression of a number of cancer-related genes in OSCC cells, including HAS3, CD44, and TP63, suggesting that DLEU1 regulates HA-CD44 signaling. Expression of DLEU1 was elevated in 71% of primary OSCC tissues, and high DLEU1 expression was associated with shorter overall survival of HNSCC patients. These data suggest that elevated DLEU1 expression contributes to OSCC development, and that DLEU1 may be a useful therapeutic target in OSCC.

Genome-wide association meta-analysis of circulating odd-numbered chain saturated fatty acids: Results from the CHARGE Consortium.

BackgroundOdd-numbered chain saturated fatty acids (OCSFA) have been associated with potential health benefits. Although some OCSFA (e.g., C15:0 and C17:0) are found in meats and dairy products, sources and metabolism of C19:0 and C23:0 are relatively unknown, and the influence of non-dietary determinants, including genetic factors, on circulating levels of OCSFA is not established.ObjectiveTo elucidate the biological processes that influence circulating levels of OCSFA by investigating associations between genetic variation and OCSFA.DesignWe performed a meta-analysis of genome-wide association studies (GWAS) of plasma phospholipid/erythrocyte levels of C15:0, C17:0, C19:0, and C23:0 among 11,494 individuals of European descent. We also investigated relationships between specific single nucleotide polymorphisms (SNPs) in the lactase (LCT) gene, associated with adult-onset lactase intolerance, with circulating levels of dairy-derived OCSFA, and evaluated associations of candidate sphingolipid genes with C23:0 levels.ResultsWe found no genome-wide significant evidence that common genetic variation is associated with circulating levels of C15:0 or C23:0. In two cohorts with available data, we identified one intronic SNP (rs13361131) in myosin X gene (MYO10) associated with C17:0 level (P = 1.37×10−8), and two intronic SNP (rs12874278 and rs17363566) in deleted in lymphocytic leukemia 1 (DLEU1) region associated with C19:0 level (P = 7.07×10−9). In contrast, when using a candidate-gene approach, we found evidence that three SNPs in LCT (rs11884924, rs16832067, and rs3816088) are associated with circulating C17:0 level (adjusted P = 4×10−2). In addition, nine SNPs in the ceramide synthase 4 (CERS4) region were associated with circulating C23:0 levels (adjusted P<5×10−2).ConclusionsOur findings suggest that circulating levels of OCSFA may be predominantly influenced by non-genetic factors. SNPs associated with C17:0 level in the LCT gene may reflect genetic influence in dairy consumption or in metabolism of dairy foods. SNPs associated with C23:0 may reflect a role of genetic factors in the synthesis of sphingomyelin.

The effects of DLEU1 gene expression in Burkitt lymphoma (BL): potential mechanism of chemoimmunotherapy resistance in BL.

Following a multivariant analysis we demonstrated that children and adolescents with Burkitt lymphoma (BL) and a 13q14.3 deletion have a significant decrease in event free survival (EFS) despite identical short intensive multi-agent chemotherapy. However, how this deletion in the 13q14.3 region is associated with a significant decrease in EFS in children and adolescents with BL is largely unknown. The gene Deleted in Lymphocytic Leukemia 1 (DLEU1) is located in the region of 13q14.3. Here, we report that DLEU1 expression is implicated in the regulation of BL programmed cell death, cell proliferation, and expression of apoptotic genes in transcription activator-like effector nuclease (TALEN)s-induced DLEU1 knockdown and DLEU1 overexpressing BL cell lines. Furthermore, NSG mice xenografted with DLEU1 knockdown BL cells had significantly shortened survival (p < 0.05 and p < 0.005), whereas those xenografted with DLEU1 overexpressing BL cells had significantly improved survival (p < 0.05 and p < 0.0001), following treatment with rituximab and/or cyclophosphamide. These data suggest that DLEU1 may in part function as a tumor suppressor gene and confer chemoimmunotherapy resistance in children and adolescents with BL.

Abstract 3838: Upregulation of DLEU1 significantly prolongs survival in a rituximab-treated DLEU1 knockout human Burkitt lymphoma (BL) xenograft NSG mouse model: DLEU1 may act as a tumor suppressor gene in pediatric BL

Abstract BACKGROUND: Burkitt lymphoma (BL) is the most common histological subtype of non-Hodgkin lymphoma (NHL) in children and adolescents (Cairo et al., Blood 2007; Miles/Cairo., BJHaem 2012). We identified that pediatric BL patients with chromosome 13q deletion, particularly 13q14.3, had significantly poorer outcome and inferior overall survival despite aggressive short, intensive multi-agent chemotherapy (Poirel/Cairo et al., Leuk 2009; Nelson/Cairo/Sanger et al., BJH 2009). Deleted in lymphocytic leukemia 1 (DLEU1) is a BL classifier gene in the 13q14.3 region (Dave et al., NEJM 2006) and interacts with C-MYC, TUBB2C and UBR1 (Stelzl et al., Cell 2005). We have previously reported a regulated DLEU1 expression significantly associated with changes in BL proliferation in vitro (Lee/Cairo et al., AACR 2015). We hypothesize that DLEU1 may have function as a tumor suppressor gene; however, functions and mechanisms underlying DLEU1 expression in the BL are poorly understood. OBJECTIVES: We hypothesize that DLEU1 may act as a tumor suppressor gene in BL and therefore examined whether up-regulation of DLEU1 results in changes in survival following targeted immunotherapy. METHODS: DLEU1 stably overexpressing Raji BL cells (Lee/Cairo et al., ASH 2013) were transfected with a firefly luciferase expression plasmid, kindly provided by Laurence Cooper MD, PhD. Four- to six- week-old female NSG (NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ) mice from The Jackson Lab. Tumor burden and tumor progression were monitored by bioluminescence imaging system. Mice were treated with either rituximab (30 mg/kg) or cyclophosphamide (25 mg/kg) by intraperitoneal injection at 7 day intervals. Survival rates were analyzed by the Kaplan-Meier method using the Prism Version 6.0 software. RESULTS: We observed that DLEU1 stably overexpressing Raji BL cells xenografted (GFP-DLEU1) mice had significantly extended survival compared to GFP control mice following treatment rituximab (59 vs 51 days, p&amp;lt;0.05, n = 8), cyclophosphamide (50.5 vs 37.5 days, p&amp;lt;0.0001, n = 12) and in combination treatment (60.5 vs 53 days, p&amp;lt;0.05, n = 12) whereas there were no significant differences in survival between WT and DLEU1-KO mice with PBS treatment. We observed that there were no significant differences of luciferase intensity in between GFP and GFP-DLEU1 mice following rituximab, cyclophosphamide or in combination treatment. CONCLUSIONS: We demonstrated that the upregulation of DLEU1 expression significantly improved the survival in DLEU1 overexpressing BL cells xenografted NSG mice following rituximab, cyclophosphamide and in combination treatment. Therefore, the up-regulation of DLEU1 expression in BL may in part result in sensitizing to chemoimmunotherapy induced survival and may result in a consideration of potential therapeutic strategies Citation Format: Sanghoon Lee, Changhong Yin, Tishi Shah, Janet Ayello, Erin Morris, Carmella van de Ven, Mitchell S. Cairo. Upregulation of DLEU1 significantly prolongs survival in a rituximab-treated DLEU1 knockout human Burkitt lymphoma (BL) xenograft NSG mouse model: DLEU1 may act as a tumor suppressor gene in pediatric BL. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3838.

Downregulation of DLEU1 Significantly Shortened Survival in a Rituximab-Treated DLEU1 Knockout Human Burkitt Lymphoma (BL) Xenograft NSG Mouse Model: DLEU1 May Act As a Tumor Suppressor Gene in Pediatric BL

BACKGROUND: Burkitt lymphoma (BL) is the most common histological subtype of non-Hodgkin lymphoma (NHL) in children and adolescents (Cairo et al., Blood, 2007; Miles/Cairo, BJH, 2012). We have previously identified secondary chromosomal aberrations in 70% of pediatric BL patients (PBL) with a C-MYC gene rearrangement (Poirel/Cairo et al., Leukemia, 2009). Specifically, we identified significantly inferior event free survival (EFS) and overall survival in children and adolescents with a specific loss of the 13q14.3 locus (Poirel/Cairo et al., Leukemia, 2009; Nelson/Cairo/Sanger et al., Br. J. Haematol., 2009). In a multivariate analysis controlling for stage, lactate dehydrogenase levels, country of treatment, and group classification, children with BL who had a 13q deletion had significantly poorer EFS compared to the remainder of patients treated with the same French-American-British (FAB) chemotherapy regimen (Poirel/Cairo et al., Leukemia, 2009). Deleted in lymphocytic leukemia 1 (DLEU1) is a BL classifier gene in the 13q14.3 region (Dave et al., NEJM, 2006) and interacts with C-MYC, Tubulin beta-2C chain (TUBB2C), E3 ubiquitin-protein ligase (UBR1), cellular tumor antigen p53, and Ras association (RalGDS/AF-6) domain family member 1 (RASSF1) (Stelzl et al., Cell, 2005). The sequence-specific Transcription Activator-Like Effector Nucleases (TALENs) have been developed for targeted genome editing in in vitro and in vivo experiments with high efficiency as a new therapeutic tool (Sander et al., Nat. Biotechnol., 2011). We have previously reported a down-regulated DLEU1 mRNA expression significantly associated with an increase in BL proliferation in vitro (Lee/Cairo et al., AACR, 2015). We hypothesize that DLEU1 may have function as a tumor suppressor gene; however, the role of DLEU1 regulating programmed cell death in BL are poorly understood.OBJECTIVES: We hypothesize that DLEU1 may act as a tumor suppressor gene in BL and whether down-regulation of DLEU1 expression results in changes in BL survival following targeted immunotherapy.METHODS: TALENs induced DLEU1 knockout Raji cells were previously generated (Lee/Cairo et al., ASH, 2013) and DLEU1 knockout cells were stably transfected with a firefly luciferase expression plasmid (ffluc-zeo), kindly provided by Laurence Cooper MD, PhD. Four- to six- week-old female NSG (NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ) mice from The Jackson Laboratory were irradiated (2.5 Gy), and then mice were subcutaneously injected with 1x106 ffluc-zeo tumor cells. Tumor burden and tumor progression were monitored by bioluminescence imaging system using the Xenogen IVIS-200 (Caliper Life Sciences). Mice were treated with either PBS, IgG isotype control, rituximab (30 mg/kg) or cyclophosphamide (25 mg/kg) and in combination by intraperitoneal (i.p) injection at 7 day intervals. Survival rates were analyzed by the Kaplan-Meier method and differences evaluated by log-rank test using the Prism Version 6.0 software.RESULTS: There were significant increases of luciferase signal intensity in DLEU1 knockout mice (DLEU1-KO) compared to that in wild type (WT) mice on day 31 of rituximab (p<0.05), cyclophosphamide (p<0.05) or rituximab and cyclophosphamide (p<0.01) combined treatment. Consistent with these initial findings in tumor growth, we found that rituximab-treated DLEU1-KO mice (n=12 per group) had a significantly shortened survival time with a median of 42 days compared to that of WT mice (n=12 per group) (52 days, p<0.005) (Figure 1A). For the rituximab and cyclophosphamide combination treated group, WT mice (n=12 per group) had a significantly extended survival time compared to the DLEU1-KO group (55.5 days vs 48 days, p<0.05) (Figure 1B). There were no significant differences in survival between WT and DLEU1-KO mice with PBS and IgG isotope treatment.CONCLUSIONS: The down-regulation of DLEU1 expression significantly decreased the survival rate in DLEU1-KO xenografted NSG mice following rituximab and in combination with cyclophosphamide treatment. Therefore, the down-regulation of DLEU1 expression in BL may in part result in immunotherapy resistance and may result in a consideration of alternative therapeutic strategies. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.