DDX11-AS1 as potential therapy targets for human hepatocellular carcinoma

Identification and functional analysis of five hub lncRNAs associated with oncogenesis of Hepatocellular Carcinoma

Liver cancer stands as one of the most pervasive and aggressive malignant neoplasms on a global scale, with hepatocellular carcinoma (HCC) accounting for over 90% of primary liver cancer cases. It has been documented that long non-coding RNA (lncRNA) plays a significant role in various pathological contexts and serves as a pivotal determinant in numerous malignancies, including HCC. Leveraging mRNA sequencing data and lncRNA expression profiles from 346 HCC samples and 50 pairs of adjacent normal samples sourced from the TCGA database, a comprehensive bioinformatics analysis was conducted. The dataset was randomly partitioned into a training subset and a validation subset. This rigorous analysis aimed to pinpoint the lncRNAs intricately linked to the oncogenesis of HCC, unveiling distinct expression patterns of these lncRNAs between normal liver and HCC samples across different stages. Moreover, the construction of a lncRNA-mRNA co-expression network led to the identification of five central lncRNA hubs (AC091057, AC099850, AC012073, DDX11-AS1, and AL035461). Subsequently, these five lncRNAs were validated using the independent validation set. In summary, this investigation successfully discerned five lncRNAs closely associated with the oncogenesis of HCC, thereby shedding light on their potential utility as diagnostic or therapeutic targets for this formidable disease.

Nanostructure-assisted drought tolerance in olive trees (Olea europaea L.): the role of Fe2O3-graphitic carbon

Olive trees are known as one of the most iconic crops in the world. Considering the increasing water deficit worldwide, implementing some profitable and empirical strategies can be inevitable upon exposure to drought stress. Therefore, the present study aimed at clarifying the beneficial role of exogenously foliar application of Fe2O3 modified carbon nitride nanostructures (control, FeSO4, C3N4 and Fe2O3/g-C3N4) to "Shengeh" olive cultivars grown at different watering levels (100, 75, and 50% ET) in two experimental years (2022 and 2023) and the pomological attributes, physiological and biochemical changes happening in the treated leaves and fruits were discussed. The results indicated that drought stress caused a significant decline in pomological attributes in this experiment, and treatments could remarkably make up for this damage. Overall, Fe2O3/g-C3N4 outperformed as compared FeSO4 and C3N4 alone, which were also efficacious in conferring tolerance to the water deficit stress. Conversely, severe drought stressed-olive fruits showed higher oil content percent in the fresh matter and water use efficiency (WUE) in oil by 30% and 52.5%, respectively, as an average of results of two years, and after Fe2O3/g-C3N4, these features in olive plants subjected to severe drought improved by an average of 35% over two years. Ca2+ and K+ in olive plants under severe drought stress declined by 50% and 83% in 2022 and 46% and 24% in 2023, while Na+ increased in the plants exposed to 50%ET stress by 48% and 57% in two successive experimental years respectively. The application of Fe2O3/g-C3N4 remarkably improved the contents of Ca2+ and K+ by 101.5% and 369%, respectively, as an average of two years. Conversely, this beneficial treatment led to a significant decline in Na+ levels by 30% in 2022 and 2% in 2023 under stressful conditions. Moreover, it decreased the 'osmolytes' content, caused a smaller decline in chlorophyll levels, and resulted in higher relative water content occurring in the treated olive leaves. The reduction of oxidative markers was a result of the increased enzymatic activity after the use of Fe2O3/g-C3N4. Therefore, this treatment is a promising strategy to achieve improved resistance in olive plants in the future.

LncRNAs-associated to genomic instability: A barrier to cancer therapy effectiveness

Although a large part of the genome is transcribed, only 1.9% has a protein-coding potential; most of the transcripts are non-coding RNAs such as snRNAs, tRNAs, and rRNAs that participate in mRNA processing and translation. In addition, there are small RNAs with a regulatory role, such as siRNAs, miRNAs, and piRNAs. Finally, the long non-coding RNAs (lncRNAs) are transcripts of more than 200 bp that can positively and negatively regulate gene expression (both in cis and trans), serve as a scaffold for protein recruitment, and control nuclear architecture, among other functions. An essential process regulated by lncRNAs is genome stability. LncRNAs regulate genes associated with DNA repair and chromosome segregation; they are also directly involved in the maintenance of telomeres and have recently been associated with the activity of the centromeres. In cancer, many alterations in lncRNAs have been found to promote genomic instability, which is a hallmark of cancer and is associated with resistance to chemotherapy. In this review, we analyze the most recent findings of lncRNA alterations in cancer, their relevance in genomic instability, and their impact on the resistance of tumor cells to anticancer therapy.

Cuproptosis-related lncRNA predict prognosis and immune response of lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) accounts for 50% of lung cancers, with high mortality and poor prognosis. Long non-coding RNA (lncRNA) plays a vital role in the progression of tumors. Cuproptosis is a newly discovered form of cell death that is highly investigated. Therefore, in the present study, we aimed to investigate the role of cuproptosis-related lncRNA signature in clinical prognosis prediction and immunotherapy and the relationship with drug sensitivity.

MATERIAL AND METHODS

Genomic and clinical data were obtained from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, and cuproptosis-related genes were obtained from cuproptosis-related studies. The prognostic signature was constructed by co-expression analysis and Cox regression analysis. Patients were divided into high and low risk groups, and then, a further series of model validations were carried out to assess the prognostic value of the signature. Subsequently, lncRNAs were analyzed for gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes Enrichment (KEGG), immune-related functions, and tumor mutation burden (TMB). Finally, we used tumor immune dysfunction and exclusion (TIDE) algorithms on immune escape and immunotherapy of cuproptosis-related lncRNAs, thereby identifying its sensitivity toward potential drugs for LUAD.

RESULTS

A total of 16 cuproptosis-related lncRNAs were obtained, and a prognostic signature was developed. We found that high-risk patients had worse overall survival (OS) and progression-free survival (PFS) and higher mortality. Independent prognostic analyses, ROC, C-index, and nomogram showed that the cuproptosis-related lncRNAs can accurately predict the prognosis of patients. The nomogram and heatmap showed a distinct distribution of the high- and low-risk cuproptosis-related lncRNAs. Enrichment analysis showed that the biological functions of lncRNAs are associated with tumor development. We also found that immune-related functions, such as antiviral activity, were suppressed in high-risk patients who had mutations in oncogenes. OS was poorer in patients with high TMB. TIDE algorithms showed that high-risk patients have a greater potential for immune escape and less effective immunotherapy.

CONCLUSION

To conclude, the 16 cuproptosis-related lncRNAs can accurately predict the prognosis of patients with LUAD and may provide new insights into clinical applications and immunotherapy.

Unveiling a Ghost Proteome in the Glioblastoma Non-Coding RNAs

Glioblastoma is the most common brain cancer in adults. Nevertheless, the median survival time is 15 months, if treated with at least a near total resection and followed by radiotherapy in association with temozolomide. In glioblastoma (GBM), variations of non-coding ribonucleic acid (ncRNA) expression have been demonstrated in tumor processes, especially in the regulation of major signaling pathways. Moreover, many ncRNAs present in their sequences an Open Reading Frame (ORF) allowing their translations into proteins, so-called alternative proteins (AltProt) and constituting the “ghost proteome.” This neglected world in GBM has been shown to be implicated in protein–protein interaction (PPI) with reference proteins (RefProt) reflecting involvement in signaling pathways linked to cellular mobility and transfer RNA regulation. More recently, clinical studies have revealed that AltProt is also involved in the patient’s survival and bad prognosis. We thus propose to review the ncRNAs involved in GBM and highlight their function in the disease.

LncRNA DDX11-AS1 accelerates hepatocellular carcinoma progression via the miR-195-5p/MACC1 pathway

INTRODUCTION AND AIM

Long non-coding RNA (lncRNA) has been shown to be a vital regulator of cancer progression, including hepatocellular carcinoma (HCC). However, the role of DEAD/H box protein 11 antisense RNA 1 (DDX11-AS1) in HCC remains to be further studied.

MATERIAL AND METHODS

The expression levels of DDX11-AS1, miR-195-5p and metastasis-associated in colon cancer-1 (MACC1) were determined by quantitative real-time PCR (qRT-PCR). Cell counting kit-8 (CCK-8), transwell and apoptosis determination assays were used to evaluate cell proliferation, migration, invasion and apoptosis, respectively. Mice xenograft models were constructed to verify the effect of DDX11-AS1 on HCC tumor growth in vivo. Furthermore, lactate production, glucose consumption, ATP level and glucose uptake were detected to assess cell glucose metabolism. The interactions among DDX11-AS1, miR-195-5p and MACC1 were verified by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Moreover, western blot (WB) analysis was performed to evaluate the protein levels.

RESULTS

DDX11-AS1 was upregulated in HCC tissues and cells, and its silencing could inhibit HCC cell proliferation, migration, invasion and glucose metabolism, and promote apoptosis in vitro. Also, DDX11-AS1 knockdown reduced HCC tumor growth in vivo. Besides, DDX11-AS1 could interact with miR-195-5p, and miR-195-5p inhibitor reversed the inhibitory effect of silenced DDX11-AS1 on HCC cell progression. In addition, MACC1 was a target of miR-195-5p, and its overexpression reversed the suppression effect of miR-195-5p on HCC cell progression.

CONCLUSION

Our data revealed that DDX11-AS1 could act as an oncogenic regulator in HCC, providing a potential therapeutic target for HCC treatment.

Landscape analysis of lncRNAs shows that DDX11-AS1 promotes cell-cycle progression in liver cancer through the PARP1/p53 axis

Although long non-coding RNAs (lncRNAs) play important roles in tumorigenesis, the underlying mechanisms are unclear. Transcriptomic analysis of 33 hepatocellular carcinoma (HCC) samples revealed that the most enriched pathway for differentially expressed genes was related to the cell cycle process, where DDX11-AS1 is the most significant lncRNA. Upregulation of DDX11-AS1 expression through demethylation was significantly associated with a poor prognosis. Further mechanistic studies revealed that DDX11-AS1 promoted the growth of HCC by interacting with PARP1 through attenuating its binding to p53, leading to downregulated expression of p53 for inhibiting the transcription of downstream genes such as p21. Knockdown of DDX11-AS1 expression in xenograft mice using anti-DDX11-AS1 oligonucleotide suppressed liver tumor proliferation. These findings indicate that DDX11-AS1 plays a role in the development of liver cancer by affecting the cell cycle.

Long non-coding RNA DDX11-AS1 promotes esophageal carcinoma cell proliferation and migration through regulating the miR-514b-3p/RBX1 axis

Esophageal carcinoma (ESCA) is one of the most aggressive malignancies with extremely high morbidity and mortality. At present, limited advancement in ESCA treatment has achieved. Therefore, it is urgent to explore the pathogenesis and progression mechanism of ESCA to provide the basis for the formulation of novel therapeutic strategies. Previous studies have found that long non-coding RNA (lncRNA) DDX11-AS1 expression enhances the paclitaxel resistance of ESCA cells. However, the mechanisms underlying the drug resistance conferred by lncRNA DDX11-AS1 in ESCA remains to be elucidated. Our research aims to clarify the role and mechanism of lncRNA DDX11-AS1 in regulating the progression of ESCA. We found that the expression of lncRNA DDX11-AS1 in ESCA tissues and cell lines was significantly upregulated. Subsequently, silencing lncRNA DDX11-AS1 significantly inhibited the proliferation, migration and invasion of ESCA cells, and induced the level of cell apoptosis. In terms of mechanism, our data showed that miR-514b-3p/RING box protein 1 (RBX1) axis played a crucial role in the oncogenic function of lncRNA DDX11-AS1. LncRNA DDX11-AS1 expression impaired the inhibitory function of miR-514b-3p on RBX1 through sponging effect. Taken together, our data support the notion that lncRNA DDX11-AS1 promotes the progression of ESCA through miR-514b-3p/RBX1 axis. Our research uncovers the novel regulatory role of lncRNA DDX11-AS1 in ESCA and lays a theoretical basis for developing novel treatment strategy of ESCA.

Functional roles of non-coding RNAs regulated by thyroid hormones in liver cancer

Recent reports have shown the important role of the non-coding part of human genome RNA (ncRNA) in cancer formation and progression. Among several kinds of ncRNAs, microRNAs (miRNA) play a pivotal role in cancer biology. Accumulating researches have been focused on the importance of non-coding genes in various diseases. In addition to miRNAs, long non-coding RNAs (lncRNAs) have also been extensively documented. Recently, the study of human liver cancer has gradually shifted to these non-coding RNAs that were originally considered "junk". Notably, dysregulated ncRNAs maybe influence on cell proliferation, angiogenesis, anti-apoptosis, and metastasis. Thyroid hormones play critical roles in human development and abnormalities in thyroid hormone levels are associated with various diseases, such as liver cancer. Thyroid hormone receptors (TR) act as ligand-activated nuclear transcription factors to affect multiple functions through the gene-level regulation in the cells and several studies have revealed that thyroid hormone associated with ncRNAs expression. TR actions are complex and tissue- and time-specific, aberrant expression of the various TR isoforms have different effects and are associated with different types of tumor or stages of development. In this review, we discuss various aspects of the research on the thyroid hormones modulated ncRNAs to affect the functions of human liver cells.

Silenced lncRNA DDX11-AS1 or up-regulated microRNA-34a-3p inhibits malignant phenotypes of hepatocellular carcinoma cells via suppression of TRAF5

Background

Studies have discussed long noncoding RNA DDX11-AS1 (DDX11-AS1)-mediated downstream mechanism in hepatocellular carcinoma (HCC). The goal of this study was to investigate the regulatory mechanism of DDX11-AS1-mediated microRNA-34a-3p (miR-34a-3p)/tumor necrosis factor receptor-associated factor 5 (TRAF5) axis on HCC cells.

Methods

DDX11-AS1, miR-34a-3p and TRAF5 expression levels in HCC were detected. The correlation of DDX11-AS1, miR-34a-3p and TRAF5 in HCC patients was analyzed by Pearson test. HCC cells were transfected with corresponding plasmid/oligonucleotide, and cell proliferation, migration, invasion, apoptosis and tumor formation ability were detected. Bioinformatics software, dual luciferase report experiment and RNA-pull down experiment analysis were applied to verify the targeting relationship between DDX11-AS1, miR-34a-3p and TRAF5.

Results

Elevated DDX11-AS1 and TRAF5 and reduced miR-34a-3p exhibited in HCC. Silenced DDX11-AS1 or up-regulated miR-34a-3p inhibited the proliferation, migration, invasion, promoted apoptosis of HCC cells and repressed the tumor growth in nude mice. In addition, DDX11-AS1 bound to miR-34a-3p to target TRAF5. Silencing TRAF5 or elevating miR-34a-3p expression mitigated up-regulated DDX11-AS1-mediated promotion of tumor growth.

Conclusion

Silenced DDX11-AS1 or up-regulated miR-34a-3p inhibits HCC cell growth via elevation of TRAF5, which could be of great benefit to find early diagnostic markers for HCC patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-01847-6.

The Genome Stability Maintenance DNA Helicase DDX11 and Its Role in Cancer

DDX11/ChlR1 is a super-family two iron–sulfur cluster containing DNA helicase with roles in DNA replication and sister chromatid cohesion establishment, and general chromosome architecture. Bi-allelic mutations of the DDX11 gene cause a rare hereditary disease, named Warsaw breakage syndrome, characterized by a complex spectrum of clinical manifestations (pre- and post-natal growth defects, microcephaly, intellectual disability, heart anomalies and sister chromatid cohesion loss at cellular level) in accordance with the multifaceted, not yet fully understood, physiological functions of this DNA helicase. In the last few years, a possible role of DDX11 in the onset and progression of many cancers is emerging. Herein we summarize the results of recent studies, carried out either in tumoral cell lines or in xenograft cancer mouse models, suggesting that DDX11 may have an oncogenic role. The potential of DDX11 DNA helicase as a pharmacological target for novel anti-cancer therapeutic interventions, as inferred from these latest developments, is also discussed.

Identification of an 11-lncRNA signature with high performance for predicting the prognosis of hepatocellular carcinoma using bioinformatics analysis

Hepatocellular carcinoma (HCC) is a common primary liver cancer with a high incidence and mortality. This study was conducted to identify a long non-coding RNA (lncRNA) signature that may serve as a predictor for HCC prognosis.RNA-seq data were extracted from The Cancer Genome Atlas database. Differentially expressed genes, lncRNAs, and miRNAs were identified in HCC (n = 374) and control samples (n = 50) and used to screen prognosis-associated lncRNA signatures. The association of the lncRNA signature with HCC prognosis was analyzed and a competitive endogenous RNA regulatory network involving the lncRNA signature was constructed.A total of 199 mRNAs, 1092 lncRNAs, and 251 miRNAs were differentially expressed between HCC and control samples. Among these lncRNAs, 11 prognosis-associated lncRNAs were used to construct a lncRNA signature. Cox regression analysis showed that patients with higher risk scores of the lncRNA signature were at risk of poor prognosis. Four lncRNAs (including LINC01517, DDX11-AS1, LINC01136, and RP11-20J15.2) and 7 miRNAs (including miR-195, miR-199b, miR-326, miR-424, and let-7c) in the ceRNA network interacted with the upregulated gene E2F2, which was associated with the overall prognosis of patients with HCC.The 11-lncRNA signature might be useful for predicting the prognosis of patients with HCC.

Long non-coding RNA DDX11-AS1 facilitates gastric cancer progression by regulating miR-873-5p/SPC18 axis

Gastric cancer (GC) is a malignant tumour with high lethality. Accruing evidence elucidates the critical adjusting role of long non-coding RNA (lncRNAs) in human cancers. DDX11 antisense RNA 1 (DDX11-AS1) was previously found to be involved in GC pathogenesis. However, the precise molecular mechanisms of DDX11-AS1 need to be further investigated. In this study, we found that DDX11-AS1 expression was up-regulated in GC tumour tissues and cells. Increased DDX11-AS1 expression was associated with advanced TNM stage and lymph node metastasis. Functionally, knockdown of DDX11-AS1 repressed cell proliferation and clone formation, while induced cell cycle arrest and apoptosis. As expected, DDX11-AS1 overexpression displayed the opposite effect. Mechanically, DDX11-AS1 enhanced SPC18 expression through acting as a ceRNA for miR-873-5p. Furthermore, the inhibitory effect of DDX11-AS1 silencing on malignant biological behaviour of GC cells was attenuated by either miR-873-5p inhibitor or SEC11A up-regulation. Moreover, suppression of DDX11-AS1 also decreased GC tumorigenesis in vivo. In conclusion, DDX11-AS1 may serve as an oncogene in GC progression by sponging miR-873-5p and promoting SPC18 expression, providing a new insight into the mechanisms of DDX11-AS1 and elucidating a promising therapy target in GC.

Identification of Diagnostic Biomarkers and Subtypes of Liver Hepatocellular Carcinoma by Multi-Omics Data Analysis

As liver hepatocellular carcinoma (LIHC) has high morbidity and mortality rates, improving the clinical diagnosis and treatment of LIHC is an important issue. The advent of the era of precision medicine provides us with new opportunities to cure cancers, including the accumulation of multi-omics data of cancers. Here, we proposed an integration method that involved the Fisher ratio, Spearman correlation coefficient, classified information index, and an ensemble of decision trees (DTs) for biomarker identification based on an unbalanced dataset of LIHC. Then, we obtained 34 differentially expressed genes (DEGs). The ability of the 34 DEGs to discriminate tumor samples from normal samples was evaluated by classification, and a high area under the curve (AUC) was achieved in our studied dataset and in two external validation datasets (AUC = 0.997, 0.973, and 0.949, respectively). Additionally, we also found three subtypes of LIHC, and revealed different biological mechanisms behind the three subtypes. Mutation enrichment analysis showed that subtype 3 had many enriched mutations, including tumor protein p53 (TP53) mutations. Overall, our study suggested that the 34 DEGs could serve as diagnostic biomarkers, and the three subtypes could help with precise treatment for LIHC.

LncRNA DDX11-AS1: a novel oncogene in human cancer

Long noncoding RNA (lncRNA) is a newly identified type of noncoding RNA with a length of more than 200 nucleotides. The latest research shows that lncRNAs play important roles in the occurrence and development of human tumours by acting both as carcinogenic genes and as tumour suppressor genes. LncRNAs plays a role in various biological processes, such as cell growth, apoptosis, migration and invasion. The newly discovered lncRNA DDX11-AS1 is abnormally highly expressed in various malignant tumours, such as hepatocellular carcinoma, colorectal cancer, osteosarcoma, bladder cancer, NSCLC and gastric cancer. DDX11-AS1 mainly regulates the expression of related genes through direct or indirect ways to perform its functions in carcinogenicity. These results indicate that DDX11-AS1 may be a marker or therapeutic target of tumours. This review summarizes the biological function and mechanism of DDX11-AS1 in the process of tumour development.

LncRNA DDX11-AS1 Promotes Bladder Cancer Occurrence Via Protecting LAMB3 from Downregulation by Sponging miR-2355-5p

Background: As a subtype of human genitourinary system cancer, the morbidity of bladder cancer (BC) continues to rise. Because of the high potentiality of cell metastasis, the 5-year survival rate of BC is relatively low. Long noncoding RNAs (lncRNAs) have been verified by a large body of literature to engage in the tumorigenesis of a few cancers. DDX11-AS1 has been elucidated as a malignancy promoter in several cancers; therefore, its mysterious role in BC attracted our interest as being well worth investigating. Aim of the Study: The primary consideration of this article was to clarify the part that DDX11-AS1 plays in the progression of BC. Methods: The expression of DDX11-AS1 in BC was revealed by quantitative real-time polymerase chain reaction. The biological functions of DDX11-AS1 in BC were evaluated through CCK-8 (Cell Counting Kit-8), EDU, TUNEL (TdT-mediated dUTP nick-end labeling), flow cytometry analysis, and Western Blot assays. Luciferase or RNA immunoprecipitation assay was used to investigate the interaction between miR-2355-5p and DDX11-AS1 (or LAMB3). Results: DDX11-AS1 manifested remarkably high level in BC and promoted the malignancy of BC. Moreover, miR-2355-5p was validated to be able to bind with DDX11-AS1 and inhibit cell proliferation in BC. Furthermore, our data suggested that LAMB3 expression was evidently upregulated in BC cells and inversely modulated by miR-2355-5p. Besides, LAMB3 may bind with miR-2355-5p. Ultimately, rescue assays indicated that the restrained development of BC in sh-DDX11-AS1#1-transfected cells could be restored by enforced expression of LAMB3. Conclusion: DDX11-AS1 facilitates the tumorigenesis of BC by the miR-2355-5p/LAMB3 axis.

DDX11-AS1exacerbates bladder cancer progression by enhancing CDK6 expression via suppressing miR-499b-5p

PURPOSE

We investigated DDX11-AS1 effects on bladder cancer (BLCA) progression to identify a new potential therapeutic target for BLCA.

METHODS

BLCA cases (n = 108) were enrolled. SW780 and J82 cells were transfected. Cell counting kit-8 (CCK-8) assay, wound healing assay and transwell migration assay was conducted. Cell cycle and apoptosis was detected by flow cytometry. Luciferase reporter assay was performed. DDX11-AS1, miR-499b-5p and CDK6 mRNA expression in tissues/cells was determined by quantitative real-time polymerase chain reaction (qRT-PCR). In vivo experiment was performed using nude mice. CDK6 and Ki67 proteins expression in cells and xenograft tumors were researched by Western blot and immunohistochemistry.

RESULTS

Overexpressed DDX11-AS1 in BLCA was associated with poor outcome of patients. Compared with siCtrl group, SW780 and J82 cells of siDDX11-AS1 group had lower OD450 value (P < 0.01), less cells in S phase, more apoptosis cells (P < 0.05), higher relative wound width (P < 0.05) and less invasive cell number (P < 0.01). DDX11-AS1 promoted CDK6 expression via inhibiting miR-499b-5p. Compared with oe-DDX11-AS1 group, SW780 cells of oe-DDX11-AS1 + miR-499b-5p mimic group and oe-DDX11-AS1 + siCDK6 group had lower OD450 value (P < 0.01), less cells in S phrase, more apoptosis cells (P < 0.01), higher relative wound width (P < 0.05) and less invasive cell numbers (P < 0.01). DDX11-AS1 knockdown inhibited SW780 cells growth in vivo and suppressed CDK6 and Ki67 expression in xenograft tumors.

CONCLUSION

DDX11-AS1 exacerbates BLCA progression by enhancing CDK6 expression via suppressing miR-499b-5p.

Long noncoding RNA DDX11-AS1 epigenetically represses LATS2 by interacting with EZH2 and DNMT1 in hepatocellular carcinoma

Long noncoding RNAs (lncRNAs), a group of transcripts without protein coding potential, have been reported to play critical roles in progression of hepatocellular carcinoma (HCC). However, the biological role of DDX11-AS1 in HCC is not clear. In this study, we found that DDX11-AS1 expression was dramatically higher in HCC tissues and cell lines. Higher DDX11-AS1 expression predicted poor overall survival of patients. Functionally, the proliferation, cell cycle progression, migration, and invasion of HCC cells were inhibited by DDX11-AS1 silencing, while promoted by ectopic expression of DDX11-AS1. RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP) assays validated that DDX11-AS1 suppressed LATS2 expression by interacting with EZH2 and DNMT1 in HCC cells. Knockdown of DDX11-AS1 increased the mRNA and protein levels of LATS2. Overexpression of LATS2 abolished the promotive effect of DDX11-AS1 on cell growth and invasion. Besides, DDX11-AS1 promoted tumor formation in vivo. The mRNA levels of LATS2 were markedly decreased in tumor tissues and negatively correlated with DDX11-AS1 expression. Taken together, our data indicated that DDX11-AS1 may be a novel oncogene in hepatocarcinogenesis by repressing LATS2, providing a potential therapeutic target for HCC treatment.

The resistance of esophageal cancer cells to paclitaxel can be reduced by the knockdown of long noncoding RNA DDX11-AS1 through TAF1/TOP2A inhibition

Esophageal cancer (EC) is one of the most common malignancies in the world. The currently used chemotherapeutic drug for the treatment of EC is paclitaxel (PTX), the efficacy of which is affected by the development of drug resistance. The present study aims to define the role of the long noncoding RNA (lncRNA) DDX11-AS1 in the progression of EC with the involvement of PTX-resistant EC cells. First, EC and adjacent normal tissue samples were collected from 82 patients with EC, after which the expression levels of DDX11-AS1, TOP2A and TAF1 were determined. The results showed that DDX11-AS1, TOP2A and TAF1 were highly expressed in EC tissues, and there was a positive correlation between the expression levels of DDX11-AS1 and TOP2A. A PTX-resistant EC cell line was constructed. Next, we evaluated the effects of DDX11-AS1 and TOP2A on the resistance of EC cells to PTX, and the regulatory relationships between DDX11-AS1, TOP2A and TAF1 were investigated. DDX11-AS1 could promote TOP2A transcription via TAF1, and the knockdown of TOP2A or DDX11-AS1 could increase the sensitivity of EC cells to PTX. The effect of DDX11-AS1 on the growth of PTX-inhibited tumors was confirmed using a tumor formation assay in nude mice. It was verified that knocking down DDX11-AS1 reduced the expression level of TOP2A and inhibited tumor growth. In conclusion, our findings suggest that DDX11-AS1 knockdown results in reduced resistance of EC cells to PTX by inhibiting TOP2A transcription via TAF1. Therefore, DDX11-AS1 knockdown could be a promising therapeutic strategy for EC.

Integrative Analysis of Dysregulated lncRNA-Associated ceRNA Network Reveals Functional lncRNAs in Gastric Cancer

Mounting evidence suggests that long noncoding RNAs (lncRNAs) play important roles in the regulation of gene expression by acting as competing endogenous RNA (ceRNA). However, the regulatory mechanisms of lncRNA as ceRNA in gastric cancer (GC) are not fully understood. Here, we first constructed a dysregulated lncRNA-associated ceRNA network by integrating analysis of gene expression profiles of lncRNAs, microRNAs (miRNAs), and messenger RNAs (mRNAs). Then, we determined three lncRNAs (RP5-1120P11, DLEU2, and DDX11-AS1) as hub lncRNAs, in which associated ceRNA subnetworks were involved in cell cycle-related processes and cancer-related pathways. Furthermore, we confirmed that the two lncRNAs (DLEU2 and DDX11-AS1) were significantly upregulated in GC tissues, promote GC cell proliferation, and negatively regulate miRNA expression, respectively. The hub lncRNAs (DLEU2 and DDX11-AS1) could have oncogenic functions, and act as potential ceRNAs to sponge miRNA. Our findings not only provide novel insights on ceRNA regulation in GC, but can also provide opportunities for the functional characterization of lncRNAs in future studies.