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Background/purpose: Accumulating evidence has suggested that treatment failure of cancer therapy can be attributed to cancer stem cells (CSCs). Among numerous regulators of cancer stemness, non-coding RNAs (ncRNAs) have gained significant attention recently. In this study, we examined the role of gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) in oral CSCs (OCSCs). Materials and methods: RNA Sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the expression of GAPLINC. Flow cytometry and sphere-forming assay were exploited to isolate OCSCs. Measurement of aldehyde dehydrogenase 1 (ALDH1) activity, CD44 expressing cells, and various phenotypic assays, such as self-renewal, migration, invasion, and colony-forming abilities, were conducted in CSCs of two types of oral cancer cells (SAS and GNM) following the knockdown of GAPLINC. A luciferase reporter was also carried out to validate the direct interaction between GAPLINC and microRNA (miR)-331-3p. Results: Our results showed that GAPLINC was overexpressed in OCSCs from patient-derived and oral cancer cell lines. We demonstrated that silencing of GAPLINC in OCSCs downregulated various CSC hallmarks, such as ALDH1 activity, percentage of CD44-expressing cells, self-renewal capacity, and colony-forming ability. Moreover, our results revealed that the effect of GAPLINC on cancer stemness was mediated by direct repression of miR-331-3p. Conclusion: These data have potential clinical implications in that we unraveled the aberrant upregulation of GAPLINC and demonstrated that suppression of GAPLINC may reduce cancer stemness via sequestering miR-331-3p.

Accumulating evidence has suggested that treatment failure of cancer therapy can be attributed to cancer stem cells (CSCs). Among numerous regulators of cancer stemness, non-coding RNAs (ncRNAs) have gained significant attention recently. In this study, we examined the role of gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) in oral CSCs (OCSCs). RNA Sequencing and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the expression of GAPLINC. Flow cytometry and sphere-forming assay were exploited to isolate OCSCs. Measurement of aldehyde dehydrogenase 1 (ALDH1) activity, CD44 expressing cells, and various phenotypic assays, such as self-renewal, migration, invasion, and colony-forming abilities, were conducted in CSCs of two types of oral cancer cells (SAS and GNM) following the knockdown of GAPLINC. A luciferase reporter was also carried out to validate the direct interaction between GAPLINC and microRNA (miR)-331-3p. Our results showed that GAPLINC was overexpressed in OCSCs from patient-derived and oral cancer cell lines. We demonstrated that silencing of GAPLINC in OCSCs downregulated various CSC hallmarks, such as ALDH1 activity, percentage of CD44-expressing cells, self-renewal capacity, and colony-forming ability. Moreover, our results revealed that the effect of GAPLINC on cancer stemness was mediated by direct repression of miR-331-3p. These data have potential clinical implications in that we unraveled the aberrant upregulation of GAPLINC and demonstrated that suppression of GAPLINC may reduce cancer stemness via sequestering miR-331-3p. [ABSTRACT FROM AUTHOR]

Introduction: In this study, we investigated the role of the long non-coding RNA GAPLINC in atherosclerosis under oxidized low-density lipoprotein (ox-LDL) treatment. Material and methods: We utilized ox-LDL exposed human aortic endothelial cells as an in-vitro model. The expression level of GAPLINC was quantified by qPCR in different times and concentrations of ox-LDL treatment conditions. Cell apoptosis rate and cell cycle profiles were assessed by flow cytometry and TUNEL assay. The target association was confirmed using a luciferase reporter assay and Western blot. Results: We found that GAPLINC expression was induced by ox-LDL treatment, but cell proliferation ability was significantly inhibited. We further confirmed that overexpressing of lncRNA GAPLINC in ox-LDL-exposed HAECs decreased cell proliferation by increasing cell apoptosis and arresting cell cycle in G2/M and S phase. Importantly, the detailed mechanistic analysis elucidated that LncRNA GAPLINC acts as a decoy to sequester miR-183-5p to prevent it from binding to target PDCD4. MiR-183-5p targets GAPLINC, and PDCD4 is a downstream target of miR-183-5p, and the cellular effects of this direct interaction were confirmed by a rescue assay experiment. Conclusions: The present study demonstrates that upregulation of lncRNA GAPLINC represses the binding of miR-183-5p to the PDCD4 promoter region and then promotes PDCD4 expression, thereby inducing cell apoptosis and suppressing endothelial cell proliferation. [ABSTRACT FROM AUTHOR]

Recent studies have identified thousands of long noncoding RNAs (lncRNAs) in mammalian genomes that regulate gene expression in different biological processes. Although lncRNAs have been identified in a variety of immune cells and implicated in immune response, the biological function and mechanism of the majority remain unexplored, especially in sepsis. Here, we identify a role for a lncRNA-gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC)-previously characterized for its role in cancer, now in the context of innate immunity, macrophages, and LPS-induced endotoxic shock. Transcriptome analysis of macrophages from humans and mice reveals that GAPLINC is a conserved lncRNA that is highly expressed following macrophage differentiation. Upon inflammatory activation, GAPLINC is rapidly down-regulated. Macrophages depleted of GAPLINC display enhanced expression of inflammatory genes at baseline, while overexpression of GAPLINC suppresses this response. Consistent with GAPLINC-depleted cells, Gaplinc knockout mice display enhanced basal levels of inflammatory genes and show resistance to LPS-induced endotoxic shock. Mechanistically, survival is linked to increased levels of nuclear NF-κB in Gaplinc knockout mice that drives basal expression of target genes typically only activated following inflammatory stimulation. We show that this activation of immune response genes prior to LPS challenge leads to decreased blood clot formation, which protects Gaplinc knockout mice from multiorgan failure and death. Together, our results identify a previously unknown function for GAPLINC as a negative regulator of inflammation and uncover a key role for this lncRNA in modulating endotoxic shock.

BackgroundLong noncoding RNAs (lncRNAs) are closely related to the occurrence and development of cancer. Gastric adenocarcinoma-associated, positive CD44 regulator, long intergenic noncoding RNA (GAPLINC) is a recently identified lncRNA that can actively participate in the tumorigenesis of various cancers. Here, we investigated the functional roles and mechanism of GAPLINC in renal cell carcinoma (RCC) development.MethodsDifferentially expressed lncRNAs between RCC tissues and normal kidney tissues were detected by using a microarray technique. RNA sequencing was applied to explore the mRNA expression profile changes after GAPLINC silencing. After gain- and loss-of-function approaches were implemented, the effect of GAPLINC on RCC in vitro and in vivo was assessed by cell proliferation and migration assays. Moreover, rescue experiments and luciferase reporter assays were used to study the interactions between GAPLINC, miR-135b-5p and CSF1.ResultsGAPLINC was significantly upregulated in RCC tissues and cell lines and was associated with a poor prognosis in RCC patients. Knockdown of GAPLINC repressed RCC growth in vitro and in vivo, while overexpression of GAPLINC exhibited the opposite effect. Mechanistically, we found that GAPLINC upregulates oncogene CSF1 expression by acting as a sponge of miR-135b-5p.ConclusionTaken together, our results suggest that GAPLINC is a novel prognostic marker and molecular therapeutic target for RCC.

Background: Long noncoding RNAs (lncRNAs) are closely related to the occurrence and development of cancer. Gastric adenocarcinoma-associated, positive CD44 regulator, long intergenic noncoding RNA (GAPLINC) is a recently identified lncRNA that can actively participate in the tumorigenesis of various cancers. Here, we investigated the functional roles and mechanism of GAPLINC in renal cell carcinoma (RCC) development. Methods: Differentially expressed lncRNAs between RCC tissues and normal kidney tissues were detected by using a microarray technique. RNA sequencing was applied to explore the mRNA expression profile changes after GAPLINC silencing. After gain- and loss-of-function approaches were implemented, the effect of GAPLINC on RCC in vitro and in vivo was assessed by cell proliferation and migration assays. Moreover, rescue experiments and luciferase reporter assays were used to study the interactions between GAPLINC, miR-135b-5p and CSF1. Results: GAPLINC was significantly upregulated in RCC tissues and cell lines and was associated with a poor prognosis in RCC patients. Knockdown of GAPLINC repressed RCC growth in vitro and in vivo , while overexpression of GAPLINC exhibited the opposite effect. Mechanistically, we found that GAPLINC upregulates oncogene CSF1 expression by acting as a sponge of miR-135b-5p. Conclusion: Taken together, our results suggest that GAPLINC is a novel prognostic marker and molecular therapeutic target for RCC. [ABSTRACT FROM AUTHOR]

Background: The long noncoding RNA (lncRNA) GAPLINC, or gastric adenocarcinoma predictive long intergenic ncRNA, plays a carcinogenic role in a variety of different tumor types. There is limited information regarding the biological function of GAPLINC in the development of esophageal squamous cell carcinoma (ESCC). Methods: Surgical tissue samples of 40 patients undergoing ESCC radical surgery were collected, including ESCC tissues and corresponding adjacent normal tissues. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of lncRNA GAPLINC in the human ESCC cell line (TE11). The function role of LncRNA GAPLINC was detected after specific siRNA interference and overexpression in the TE11 cell line. The effects of LncRNA GAPLINC on ESCC cell proliferation, migration and invasion abilities were investigated by flow cytometry, using the Cell Counting Kit-8 (CCK-8), and by Transwell migration assays, respectively. Results: The expression of lncRNA GAPLINC in ESCC tissues was significantly higher than that in corresponding adjacent normal tissues (P< 0.05) and correlated with the degree of tumor differentiation (P< 0.05). Compared with human esophageal normal epithelial cell lines, the expression of LncRNA GAPLINC was significantly higher in the human ESCC cell line (P< 0.05). CCK-8 assays showed that LncRNA GAPLINC overexpression increased the growth rate of cells (P< 0.05). Transwell experiments showed that LncRNA GAPLINC overexpression increased the ability of cell migration and invasion compared to control cells (P< 0.05). Annexin V assay revealed that LncRNA GAPLINC silencing increased early stage apoptosis (P< 0. 05). Conclusion: Our results suggest that LncRNA GAPLINC may be used as a biomarker for the diagnosis and monitoring of ESCC, and may play an oncogenic role in ESCC. [ABSTRACT FROM AUTHOR]

In this study, we investigated the role of a long non‐coding RNA GAPLINC in angiogenesis using human umbilical vein endothelial cells (HUVEC). We found that hypoxia and hypoxia‐inducible factor 1α (HIF‐1α) increased the expression of GAPLINC in HUVEC cells. Moreover, GAPLINC overexpression down‐regulated miR‐211 and up‐regulated Bcl2 protein expression. Further rescue experiments confirmed that hypoxia directly increased GAPLINC expression. GAPLINC overexpression also increased cell migration and vessel formation which promoted angiogenesis, and these changes were attributed to the increased expression of vascular endothelial growth factor receptors (VEGFR) and delta‐like canonical notch ligand 4 (DLL4) receptors. Finally, we demonstrated that GAPLINC promotes vessel formation and migration by regulating MAPK and NF‐kB signalling pathways. Taken together, these findings comprehensively demonstrate that overexpression of GAPLINC increases HUVEC cells angiogenesis under hypoxia condition suggesting that GAPLINC can be a potential target for critical limb ischaemia (CLI) treatment. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Recent evidence shows that gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) acts as a critical role in the proliferation and metastasis in several tumors. We aimed to explore the expression pattern, function, and potential mechanism of GAPLINC in glioblastoma multiforme (GBM). PATIENTS AND METHODS: The expression levels of GAPLINC and its clinical significance were determined by analyzing TCGA datasets. RT-PCR was performed to detect the levels of GAPLINC and miR-331-3p. CCK-8, colony formation, EdU assays, wound healing assay and transwell invasion assay were performed to analyze the effect of GAPLINC on GBM behaviors. MiRNAs that may interact with GAPLINC were predicted using StarBase and RegRNA 2.0. A luciferase reporter assay was used to detect the targeting effect of GAPLINC on miR-331-3p. RESULTS: We found that GAPLINC expression was significantly up-regulated in both GBM tissues and cell lines. The overexpression of GAPLINC was associated with shorter overall survival and disease-free survival. Functional assays indicated that GAPLINC silencing suppressed GBM cells proliferation, migration, and invasion, and promoted apoptosis. In the mechanism, we found that GAPLINC acted as a competing endogenous RNA to sponge miR-331-3p and knockdown of GAPLINC promoted the expression of miR-331-3p. CONCLUSIONS: Our findings suggested that GAPLINC served as an oncogenic lncRNA in GBM through negative modulation of miR-331-3p, providing a novel treatment targeting for GBM. [ABSTRACT FROM AUTHOR]

Background: Dysregulated long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) play key roles in the development of human cancers. LncRNA GAPLINC has been reported to be increased in gastric cancer (GC) tissues.Methods: Real-time PCR assays were used to measure expressions of GAPLINC, miR-378, and MAPK1 mRNA. Western blot assays were employed to examine MAPK1 protein expression. Cell proliferation and cell cycle were measured by CCK-8 and propidium iodide-detection assays, respectively. The interaction between GAPLINC and miR-378 was confirmed by site-directed mutagenesis and luciferase assays. Luciferase assays were also used to study whether GAPLINC was able to act as a molecular sponge of miR-378 to modulate MAPK1 expression.Results: The lncRNA GAPLINC expression was upregulated and positively correlated with MAPK1 expression in gastric cancer tissues and cells. Additionally, lncRNA GAPLINC promoted the expression of MAPK1 and the enhancement of GC cell proliferation and cell cycle progression by LncRNA GAPLINC was dependent on MAPK1 in vitro and in vivo. Consequently, we found that miR-378 expression was inversely correlated with GAPLINC expression in GC tissues and cells. miR-378 could directly bind to GAPLINC and decreased GAPLINC expression, thus reducing MAPK1 expression. Furthermore, overexpression of miR-378 inhibited MAPK1 expression, cell proliferation, and cell cycle progression of gastric cancer cells, while these effects were abrogated by upregulating lncRNA GAPLINC expression.Conclusion: Taken together, lncRNA GAPLINC promotes gastric cancer cell proliferation by acting as a molecular sponge of miR-378 to modulate MAPK1 expression. [ABSTRACT FROM AUTHOR]

Hypoxia-inducible factor (HIF) activates the transcription of genes involved in cancer progression. Recently, HIF was reported to regulate the transcription of non-coding RNAs. Here, we show that the transcription of a long non-coding RNA (lncRNA), Gastric Adenocarcinoma Associated, Positive CD44 Regulator, Long Intergenic Non-Coding RNA (GAPLINC), is directly activated by HIF-1α in gastric cancer (GC). GAPLINC was overexpressed in GC tissues and promoted tumor migration and invasive behavior. GAPLINC overexpression was associated with poor prognosis in GC patients. Luciferase reporter assays and chromatin immunoprecipitation assays confirmed that HIF-1α binds to the promoter region of GAPLINC and activates its transcription. GAPLINC knockdown inhibited hypoxia-induced tumor proliferation in vivo. Taken together, our results identified a novel role for HIF transcriptional pathways in GC tumorigenesis mediated by the regulation of the lncRNA GAPLINC, and suggest GAPLINC as a novel therapeutic target for reversing chemoradioresistance and prolonging survival.

The prognosis of CCA is extremely poor, making it one of the most lethal cancers. Therefore, there is a need to elucidate the pathogenic mechanisms of CCA. In this study, we aimed at identifying lncRNA-related prognostic signatures for CCA through bioinformatics analysis and further validated their functions in CCA tumorigenesis and progression. The RNA-seq data of CCA were downloaded from public databases. Differentially expressed lncRNAs (DElncRNAs) were screened. Then, candidate OS- and DFS-related DElncRNAs were selected through Kaplan–Meier survival analysis. Furthermore, LASSO regression was performed to establish the OS and DFS signatures, respectively. Multivariate COX models and nomograms for overall survival (OS) and disease-free survival (DFS) were established based on OS/DFS signature and clinical data. Hub lncRNAs were identified and enrichment analyses were performed to explore their potential functions. Finally, in vitro and in vivo models were used to validate the effects of the hub lncRNAs in CCA tumorigenesis and progression. A total of 925 DElncRNAs were selected, of which six candidate OS-related lncRNAs and 15 candidate DFS-related lncRNAs were identified. The OS and DFS signatures were then established using four lncRNAs, respectively. We found that the OS signature and vascular invasion were independent risk factors for the OS of CCA, while the DFS signature, vascular invasion, and CA19–9 were independent risk factors for the DFS of CCA. Then, nomograms were established to achieve personalized CCA recurrence and death prediction. Furthermore, our study uncovered that MIR4435-2HG and GAPLINC might play crucial roles in CCA progression and be selected as hub lncRNAs. GO and KEGG enrichment analyses revealed that the two hub lncRNAs were closely related to CCA tumorigenesis. Finally, we demonstrated that MIR4435-2HG and GAPLINC can stimulate CCA proliferation and migration in vitro and in vivo. The established OS and DFS signatures are independent risk factors for OS and DFS of CCA patients, respectively. MIR4435-2HG and GAPLINC were identified as hub lncRNAs. In vitro and in vivo models revealed that MIR4435-2HG and GAPLINC can prompt CCA progression, which might be novel prognostic biomarkers and therapeutic targets for CCA. • The established OS and DFS signatures are independent risk factors for OS and DFS of CCA patients, respectively. • MIR4435-2HG and GAPLINC were identified as hub lncRNAs. • In vitro and in vivo models revealed that MIR4435-2HG and GAPLINC can prompt CCA progression, which might be novel prognostic biomarkers and therapeutic targets for CCA. [ABSTRACT FROM AUTHOR]

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC), a newly identified lincRNA, was reported to be aberrantly expressed in several kinds of cancers and played an important role in tumor progression. This study was performed to systematically estimate the prognostic role of GAPLINC expression in cancer patients. Several electronic databases, including PubMed, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wan Fang databases were searched for potential literature (updated to September 3, 2018). The pooled hazard ratios (HRs), odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with a fixed effects model using Stata12.0 software. The pooled results indicated that elevated GAPLINC was significantly related to shorter overall survival (OS) (HR = 1.66, 95%CI: 1.40–1.93, p < 0.001), which was further validated using The Cancer Genome Atlas (TCGA) dataset. Furthermore, high GAPLINC expression was correlated with higher tumor grade (OR = 1.91, 95%CI: 1.35–2.70, p < 0.001), positive lymph node metastasis (OR = 2.80, 95%CI: 1.69–4.64, p < 0.001), deeper infiltration depth (OR = 2.44, 95%CI: 1.43–4.17, p = 0.001) and advanced clinical stage (OR = 3.54, 95%CI: 2.13–5.88, p < 0.001). Our results suggest that elevated GAPLINC was associated with poor clinical outcomes and might serve as a promising prognostic biomarker in cancer survivors. [ABSTRACT FROM AUTHOR]