Long non-coding RNA FEZF1-AS1 facilitates cell proliferation and migration in colorectal carcinoma

Prognostic Value of Long Noncoding RNAs in Patients with Gastrointestinal Cancer: A Systematic Review and Meta-Analysis

Gastrointestinal cancers (GICs) are a huge threat to human health, which mainly include esophageal, gastric, and colorectal cancers. The purpose of this study was to clarify the prognostic value of long noncoding RNAs (lncRNAs) in GICs. A total of 111 articles were included, and 13103 patients (3123 with esophageal cancer, 4972 with gastric cancer, and 5008 with colorectal cancer) were enrolled in this study. The pooled hazard ratio (HR) values and corresponding 95% confidence interval (95% CI) of overall survival (OS) related to different lncRNA expressions in esophageal, gastric, colorectal, and gastrointestinal cancer patients were 1.92 (1.70–2.16), 1.96 (1.77–2.16), 2.10 (1.87–2.36), and 2.00 (1.87–2.13), respectively. We have identified 74 lncRNAs which were associated closely with poor prognosis of GIC patients, including 58 significantly upregulated lncRNA expression and 16 significantly downregulated lncRNA expression. In addition, 47 of the included studies revealed relative mechanisms and 12 of them investigated the correlation between lncRNAs and microRNAs. Taken together, this meta-analysis supports that specific lncRNAs are significantly related to the prognosis of GIC patients and may serve as novel markers for predicting the prognosis of GIC patients. Furthermore, lncRNAs may have a promising contribution to lncRNA-based targeted therapy and clinical decision-making in the future.

Long Noncoding RNA FEZF1-AS1 Promotes Proliferation and Inhibits Apoptosis in Ovarian Cancer by Activation of JAK-STAT3 Pathway

BACKGROUND Long noncoding RNAs (lncRNAs) have been acknowledged as important regulators in human cancers, including ovarian cancer. Several reports identified lncRNA FEZF1-AS1 as an oncogene in gastric cancer, colorectal carcinoma, and non-small cell lung cancer (NSCLC). However, the function of FEZF1-AS1 in ovarian cancer remains largely unknown. This study was aimed to investigate the role of FEZF1-AS1 in ovarian cancer. MATERIAL AND METHODS FEZF1-AS1 expression levels in pairs of ovarian cancer tissues and adjacent normal tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Kaplan-Meier curve analysis was used to determine the correlation between FEZF1-AS1 expression and prognosis in ovarian cancer patients. The effects of FEZF1-AS1 knockdown on ovarian cancer cell proliferation, cell-cycle, and apoptosis were analyzed by Cell Counting Kit-8 (CCK8) and Fluorescence activated Cell Sorting (FACS) assays. Western blot was utilized to assess the effect of FEZF1-AS1 on the activation of JAK-STAT3 pathway. RESULTS FEZF1-AS1 was overexpressed in ovarian cancer tissues compared to adjacent normal tissues. Consistently, FEZF1-AS1 expression was also upregulated in ovarian cancer cell lines compared with normal cell line. Furthermore, higher expression of FEZF1-AS1 in ovarian cancer patients contributed to poorer prognosis. FEZF1-AS1 knockdown significantly suppressed the proliferation and promoted apoptosis in ovarian cancer cells. In mechanism, FEZF1-AS1 regulated activation of JAK-STAT3 signaling pathway by modulating STAT3 phosphorylation. Knockdown of FEZF1-AS1 significantly impaired the phosphorylation of STAT3. CONCLUSIONS Our study demonstrated that FEZF1-AS1 exerted an oncogenic role in ovarian cancer via modulating JAK-STAT3 pathway.

lncRNA FEZF1‑AS1 contributes to cell proliferation, migration and invasion by sponging miR‑4443 in hepatocellular carcinoma

As one of the most common and aggressive cancer types, hepatocellular carcinoma (HCC) leads to a large number of fatalities every year. However, the pathogenesis of HCC remains largely unknown. In the present study, it was identified that FEZF1-AS1 was significantly upregulated in HCC cell lines and tissues, as determined by reverse transcription-quantitative polymerase chain reaction. Additionally, it was observed that higher expression of FEZF1-AS1 in patients with HCC indicated poorer prognosis. Furthermore, it was identified that knockdown of FEZF1-AS1 markedly inhibited the proliferation, colony formation, migration and invasion of Hep3B and Huh7 cells, as determined by Cell Counting Kit-8, colony formation and Transwell assays. In terms of mechanism, it was observed that FEZF1-AS1 acted as a sponge for microRNA (miR)-4443. The results of a luciferase reporter assay revealed that overexpression of miR-4443 significantly inhibited the luciferase activity in Hep3B and Huh7 cells. Additionally, miR-4443 overexpression markedly inhibited the expression of FEZF1-AS1, and vice versa. It was additionally identified that miR-4443 was downregulated in HCC tissues. There was an inverse correlation between the expression of miR-4443 and FEZF1-AS1 in HCC tissues. Furthermore, through functional experiments, it was identified that knockdown of FEZF1-AS1 significantly inhibited the proliferation, migration and invasion of HCC cells, whereas inhibition of miR-4443 reversed these effects. Collectively, the present results demonstrated that FEZF1-AS1 acts as an oncogene by acting as a sponge for miR-4443.

Role of lncRNA and EZH2 Interaction/Regulatory Network in Lung Cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts and longer than 200 nucleotides. LncRNAs have been demonstrated to modulate gene expression at transcriptional, post-transcriptional, as well as epigenetic levels in lung cancer. Interestingly, compelling studies have revealed that lncRNAs participated in the EZH2 oncogenic regulatory network. EZH2 plays an important role in the initiation, progression and metastasis of cancer. On one hand, lncRNAs can directly bind to EZH2, recruit EZH2 to the promoter region of genes and repress their expression. On the other hand, lncRNAs can also serve as EZH2 effectors or regulators. In this review, we summarized the types of lncRNA-EZH2 interaction and regulatory network identified till date and discussed their influence on lung cancer. Better understanding regarding the interaction and regulatory network will provide new insights on lncRNA- or EZH2-based therapeutic development in lung cancer.

Long Noncoding RNA FEZF1-AS1 Promotes Osteosarcoma Progression by Regulating the miR-4443/NUPR1 Axis

Long noncoding RNA (lncRNA) FEZF1-AS1 was demonstrated to facilitate cell proliferation and migration in some cancers. However, the functions of FEZF1-AS1 and its molecular mechanism in osteosarcoma remain to be elucidated. In our study, we found that the expression of FEZF1-AS1 was upregulated in osteosarcoma samples and cell lines compared with normal tissues or cells. Besides, we showed that the expression levels of FEZF1-AS1 in osteosarcoma patients were positively correlated with tumor metastasis and TNM stage. Additionally, FEZF1-AS1 knockdown inhibited cell proliferation, migration, and invasion in U2OS and MG63 cells, while upregulation had the opposite effects in vitro. Moreover, FEZF1-AS1 depletion inhibited tumor growth and metastasis in vivo. We found that FEZF1-AS1 sponged miR-4443 to promote NUPR1 expression in U2OS and MG63 cells. Furthermore, knockdown of miR-4443 abrogated FEZF1-AS1 silencing-induced inhibition of cell proliferation, migration, and invasion in osteosarcoma. Finally, we found that restoration of NUPR1 rescued the proliferation, migration, and invasion abilities of FEZF1-AS1-depleted U2OS and MG63 cells. Our study indicated that FEZF1-AS1 could promote osteosarcoma progression by sponging miR-4443 to promote NUPR1 expression. The FEZF1-AS1/miR-4443/NUPR1 axis may act as a novel therapeutic strategy for osteosarcoma treatment.

FEZF1 is an Independent Predictive Factor for Recurrence and Promotes Cell Proliferation and Migration in Cervical Cancer

The Fez family zinc finger protein 1 (FEZF1), a critical transcription factor in nervous system development, has been implicated in cancer progression recently. However, its clinical significance remains unknown. By analyzing gene expression data of eight most common cancer types from The Cancer Genome Atlas (TCGA), we found that FEZF1 prominently associated with the recurrence-free survival of cervical cancer patients (P<0.001) and was an independent diagnostic factor for cervical cancer recurrence (P=0.002). Moreover, FEZF1 expression was significantly higher in the tumor samples from cervical cancer patients with relapse in TCGA(P=0.015). By RNA interference, we knocked down FEZF1 and found that cell proliferation, growth and migration were significantly decreased in C33A and SiHa cells. Meanwhile, FEZF1 knockdown also attenuated the growth of C33A cells in nude mice. In contrast, expression of FEZF1 promoted cell proliferation, growth and migration in HeLa cells. Using chromatin immunoprecipitation (ChIP) assay, we revealed that FEZF1 could bind to multiple key genes in the Wnt signaling pathway in HeLa cells. Furthermore, analysis of the levels of β-catenin protein, the core component of the Wnt pathway, and downstream effector genes of the pathway showed that FEZF1 could activate the Wnt pathway. Together, these results suggest that FEZF1 promotes cell proliferation and migration possibly by acting as a transcriptional activator of the Wnt signaling pathway in cervical cancer, and also provide a valuable molecular predictive marker for cervical cancer recurrence.

LncRNA-FEZF1-AS1 Promotes Tumor Proliferation and Metastasis in Colorectal Cancer by Regulating PKM2 Signaling

Purpose: Long non-coding RNAs (lncRNAs) play key roles in human cancers. Here, FEZF1-AS1, a highly overexpressed lncRNA in colorectal cancer, was identified by lncRNA microarrays. We aimed to explore the roles and possible molecular mechanisms of FEZF1-AS1 in colorectal cancer.Experimental Design: LncRNA expression in colorectal cancer tissues was measured by lncRNA microarray and qRT-PCR. The functional roles of FEZF1-AS1 in colorectal cancer were demonstrated by a series of in vitro and in vivo experiments. RNA pull-down, RNA immunoprecipitation and luciferase analyses were used to demonstrate the potential mechanisms of FEZF1-AS1.Results: We identified a series of differentially expressed lncRNAs in colorectal cancer using lncRNA microarrays, and revealed that FEZF1-AS1 is one of the most overexpressed. Further validation in two expanded colorectal cancer cohorts confirmed the upregulation of FEZF1-AS1 in colorectal cancer, and revealed that increased FEZF1-AS1 expression is associated with poor survival. Functional assays revealed that FEZF1-AS1 promotes colorectal cancer cell proliferation and metastasis. Mechanistically, FEZF1-AS1 could bind and increase the stability of the pyruvate kinase 2 (PKM2) protein, resulting in increased cytoplasmic and nuclear PKM2 levels. Increased cytoplasmic PKM2 promoted pyruvate kinase activity and lactate production (aerobic glycolysis), whereas FEZF1-AS1-induced nuclear PKM2 upregulation further activated STAT3 signaling. In addition, PKM2 was upregulated in colorectal cancer tissues and correlated with FEZF1-AS1 expression and patient survival.Conclusions: Together, these data provide mechanistic insights into the regulation of FEZF1-AS1 on both STAT3 signaling and glycolysis by binding PKM2 and increasing its stability. Clin Cancer Res; 24(19); 4808-19. ©2018 AACR.

Long noncoding RNA kcna3 inhibits the progression of colorectal carcinoma through down-regulating YAP1 expression

Long non-coding RNAs (lncRNAs) regulate diverse cellular processes, and their anomalous expression exert an essential role in the progression of many kinds of cancers, including colorectal carcinoma (CRC). The objective of this study was to investigate the role of lncRNA kcna3 and its underlying mechanism in CRC progression. The expression of lncRNA kcna3 in human CRC tissues and the adjacent non-tumor tissues was evaluated by RT-PCR. The correlations between lncRNA kcna3 expression levels and the overall survival (OS), as well as the clinicopathological features of CRC patients were analyzed. Gain-of-function and loss-of-function experiments were used to evaluate the effects of lncRNA kcna3 on the proliferation, apoptosis, migration, invasion and tumorigenesis of colon cancer SW620 cells. We found that lncRNA kcna3 was lowly expressed in CRC tissues, and its low expression was closely associated with patients' higher TNM grade and the higher occurrence rate of lymphatic metastasis and distant metastasis, as well as shorter OS. Enhanced expression of lncRNA kcna3 inhibited SW620 cells' proliferation, migration and invasion, and induced cell apoptosis in vitro, and repressed CRC tumor growth in vivo. Whereas knockdown of lncRNA kcna3 showed the opposite results. Mechanistically, up-regulation of lncRNA kcna3 decreased YAP1 protein expression and accelerated its degradation. The effects of lncRNA kcna3 overexpression on cell growth and tumorigenesis inhibition and apoptosis promotion were weakened when the expression of YAP1 was up-regulated. In conclusion, this study revealed that lncRNA kcna3 exerts a tumor-inhibit role in CRC progression through down-regulating YAP1 expression, indicating that lncRNA kcna3/YAP1 might be served as a new prognostic biomarker and therapeutic target for CRC.

MicroRNAs, long noncoding RNAs, and circular RNAs: potential tumor biomarkers and targets for colorectal cancer

Noncoding RNAs (ncRNAs) can be divided into microRNAs (miRNAs), long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), pRNAs, and tRNAs. Traditionally, miRNAs exert their biological function mainly through the inhibition of translation via the induction of target RNA transcript degradation. lncRNAs and circRNAs were once considered to have no potential to code proteins. Here, we will review the current knowledge on ncRNAs in relation to their origins, characteristics, and functions. We will also review how ncRNAs work as competitive endogenous RNA, gene transcription and expression regulators, and RNA-binding protein sponges in colorectal cancer (CRC). Notably, except for the abovementioned mechanisms, recent advances revealed that lncRNAs can also act as the precursor of miRNAs, and a small portion of lncRNAs and circRNAs was verified to have the potential to code proteins, providing new evidence for the significance of ncRNAs in CRC tumorigenesis and development.

Long non-coding RNA FEZF1-AS1 promotes cell invasion and epithelial-mesenchymal transition through JAK2/STAT3 signaling pathway in human hepatocellular carcinoma

Long non-coding RNAs (lncRNAs) have emerged as key regulators in the development of hepatocellular carcinoma (HCC). In the present study, we explored the expression profile and biological role of lncRNA FEZF1-AS1 in HCC. We observed remarkable upregulation of FEZF1-AS1 in HCC tissues and cell lines, and high FEZF1-AS1 expression was correlated with aggressive phenotypes and poor prognosis of HCC patients. Furthermore, we found that FEZF1-AS1 knockdown markedly inhibited the proliferation of HCC cells by inducing cell cycle arrest. In addition, FEZF1-AS1 knockdown suppressed HCC tumor growth in vivo. Moreover, FEZF1-AS1 knockdown inhibited the migration and invasion of HCC cells through suppression of JAK2/STAT3 signaling-mediated epithelial-mesenchymal transition (EMT). In conclusion, the present study for the first time demonstrated that FEZF1-AS1 serves as an oncogenic lncRNA in human HCC and implicated FEZF1-AS1 as a valuable therapeutic target for HCC treatment.

Roles of long noncoding RNAs in colorectal cancer metastasis

Colorectal cancer (CRC) is the 3^rd most common malignancies worldwide. Metastasis is responsible for more than 90% CRC patients' death. Long noncoding RNAs (lncRNAs) are an important class of transcribed RNA molecules greater than 200 nucleotides in length. With the development of whole genome sequencing technologies, they have been gained more attention. Accumulating evidences suggest that abnormal expression of lncRNAs in diverse diseases are involved in various biological functions such as proliferation, apoptosis, metastasis and differentiation by acting as epigenetic, splicing, transcriptional or post-transcriptional regulators. Aberrant expression of lncRNAs has also been found in CRC. Besides, recent studies have indicated that lncRNAs play important roles in tumourigenesis and cancer metastasis. They participate in the process of metastasis by activing or inhibiting the metastatic pathways. However, their functions on the development of cancer metastasis are poorly understood. In this review, we highlight the findings of roles for lncRNAs in CRC metastasis and review the metastatic pathways of lncRNAs leading to cancer metastasis in CRC, including escape of apoptosis, epithelial-mesenchymal transition (EMT), angiogenesis and invasion, migration and proliferation. Furthermore, we also discuss the potential clinical application of lncRNAs in CRC as diagnostic markers and therapeutic targets.

Long non-coding RNA-CTD-2108O9.1 represses breast cancer metastasis by influencing leukemia inhibitory factor receptor

Breast cancer (BC) is an aggressive malignant disease in women worldwide with a high tendency to metastasize. However, important biomarkers for BC metastasis remain largely undefined. In the present study, we identified that long non-coding RNA-CTD-2108O9.1 is downregulated in BC tissues and cells and acts as a metastatic inhibitor of BC. Mechanistic investigation determined that lncRNA-CTD-2108O9.1 represses metastasis by targeting leukemia inhibitory factor receptor (LIFR), which is designated as a metastasis suppressor in BC. Our study characterizes a significant tumor suppressor active in BC metastasis repression through the known metastasis inhibitor LIFR.

Identification of aberrantly expressed long non-coding RNAs in stomach adenocarcinoma

Aim

Stomach adenocarcinoma (STAD) is a common malignancy worldwide. This study aimed to identify the aberrantly expressed long non-coding RNAs (lncRNAs) in STAD.

Results

Total of 74 DElncRNAs and 449 DEmRNAs were identified in STAD compared with paired non-tumor tissues. The DElncRNA/DEmRNA co-expression network was constructed, which covered 519 nodes and 2993 edges. The qRT-PCR validation results of DElncRNAs were consistent with our bioinformatics analysis based on RNA-sequencing. The DEmRNAs co-expressed with DElncRNAs were significantly enriched in gastric acid secretion, complement and coagulation cascades, pancreatic secretion, cytokine-cytokine receptor interaction and Jak-STAT signaling pathway. The expression levels of the nine candidate DElncRNAs in TCGA database were compatible with our RNA-sequencing. FEZF1-AS1, HOTAIR and LINC01234 had the potential diagnosis value for STAD.

Materials and Methods

The lncRNA and mRNA expression profile of 3 STAD tissues and 3 matched adjacent non-tumor tissues was obtained through high-throughput RNA-sequencing. Differentially expressed lncRNAs/mRNAs (DElncRNAs/DEmRNAs) were identified in STAD. DElncRNA/DEmRNA co-expression network construction, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were conducted to predict the biological functions of DElncRNAs. Quantitative real-time polymerase chain reaction (qRT-PCR) was subjected to validate the expression levels of DEmRNAs and DElncRNAs. Moreover, the expression of DElncRNAs was validated through The Cancer Genome Atlas (TCGA) database. The diagnosis value of candidate DElncRNAs was accessed by receiver operating characteristic (ROC) analysis.

Conclusions

Our work might provide useful information for exploring the tumorigenesis mechanism of STAD and pave the road for identification of diagnostic biomarkers in STAD.

Epigenetic regulation of long non-coding RNAs in gastric cancer

Gastric cancer is one of the most common cancers and is the second leading cause of cancer mortality worldwide. Therefore, it is urgent to explore new molecular biomarkers for early diagnosis, early treatment and prognosis for gastric cancer patients. Recently, increasing evidence has shown that epigenetic changes, such as aberrant DNA methylation, histone modifications, and noncoding RNAs (ncRNAs) expression, play substantial roles in the development and progression of malignancies. Among these changes, long non-coding RNAs (lncRNAs), a novel class of ncRNAs, are emerging as highly versatile actors in a variety of cellular processes by regulating gene expression at the epigenetic level as well as at the transcriptional and post-transcriptional levels. Hundreds of lncRNAs become dysregulated in the various pathological processes of gastric cancer, and multiple lncRNAs have been reported to function as tumor-suppressors or oncogenes, although the underlying mechanisms are still under investigation. Here, we provide an overview of the epigenetic regulation of chromatin and the molecular functions of lncRNAs; we focus on lncRNA-mediated epigenetic regulation of cancer-related gene expression in gastric cancer, as well as discuss the clinical implications of lncRNAs on epigenetic-related cancer treatments, which may contribute helpful approaches for the development of new potential strategies for future diagnosis and therapeutic intervention in human cancers.

Pseudogene PHBP1 promotes esophageal squamous cell carcinoma proliferation by increasing its cognate gene PHB expression

Natural antisense transcripts (NATs) as one of the most diverse classes of long noncoding RNAs (lncRNAs), have been demonstrated involved in fundamental biological processes in human. Here, we reported that human prohibitin gene pseudogene 1 (PHBP1) was upregulated in ESCC, and increased PHBP1 expression in ESCC was associated with clinical advanced stage. Functional experiments showed that PHBP1 knockdown inhibited ESCC cells proliferation, colony formation and xenograft tumor growth in vitro and in vivo by causing cell-cycle arrest at the G1-G0 phase. Mechanisms analysis revealed that PHBP1 transcript as an antisense transcript of PHB is partially complementary to PHB mRNA and formed an RNA-RNA hybrid with PHB, consequently inducing an increase of PHB expression at both the mRNA and protein levels. Furthermore, PHBP1 expression is strongly correlated with PHB expression in ESCC tissues. Collectively, this study elucidates an important role of PHBP1 in promoting ESCC partly via increasing PHB expression.

lncRNA FEZF1-AS1 Is Associated With Prognosis in Lung Adenocarcinoma and Promotes Cell Proliferation, Migration, and Invasion

Long noncoding RNAs (lncRNAs) have been reported to play important roles in tumorigenesis. In the present study, we demonstrated that lncRNA forebrain embryonic zinc finger protein 1 (FEZF1) antisense RNA1 (FEZF1-AS1) is markedly upregulated in human lung adenocarcinoma (LAD) tissues and cell lines and is associated with poor prognosis. Loss of function revealed that deletion of FEZF1-AS1 expression significantly inhibited the LAD cell proliferation, invasion, and migration. Further studies revealed that downregulation of FEZF1-AS1 reduced mRNA and protein expression of its sense-cognate gene FEZF1 in LAD cells, and vice versa. Correlation analysis indicated that there was a positive correlation between FEZF1-AS1 and FEZF1 expression in LAD tissues. Additionally, rescue assay confirmed that the function of FEZF1-AS1 in LAD was mediated by FEZF1. Our findings suggested that dysregulation of FEZF1-AS1 contributed to the progression of LAD, which might be a potential target for LAD therapy.

Upregulated NNT-AS1, a long noncoding RNA, contributes to proliferation and migration of colorectal cancer cells in vitro and in vivo

The expression patterns of the long non-coding RNA Nicotinamide Nucleotide Transhydrogenase-antisense RNA1 (NNT-AS1) have not been investigated in the context of cancer. In this study, we aim to investigate the NNT-AS1 expression level in colorectal cancer (CRC) patients and its potential roles in tumor biology. We measured the expression of NNT-AS1 in 70 paired tumor tissues and adjacent normal tissues. NNT-AS1 was expressed higher in tumor tissues than that in adjacent noncancer tissues, and higher expression of NNT-AS1 was significantly correlated with lymph node metastasis (Yes vs. No, P=0.004), TNM stage (I/II vs. III/IV, P=0.004), vessel invasion (Yes vs. No, P=0.002) and differentiation (well and moderate vs. poor, P=0.008). Multivariate analyses revealed that NNT-AS1 expression was an independent predictor of overall survival (P=0.0174) and progression free survival (P=0.0132) for CRC. Knockdown of NNT-AS1 using small interfering RNA (siRNA) significantly impaired CRC cell proliferation, migration and invasion in vitro and silencing NNT-AS1 also suppressed tumor growth and metastasis in nude mice. The western blot experiments revealed that silencing NNT-AS1 inhibited epithelial-mesenchymal transition (EMT) and inactivated MAPK/Erk signaling pathway in CRC cell lines. In conclusion, our studies implied that NNT-AS1 may involve in the development and progression of CRC via its regulation of cell proliferation, migration, and invasion by NNT-AS1-mediated activating of MAPK/Erk signaling pathway and EMT. NNT-AS1 may be a useful diagnostic and prognostic biomarker and a potential therapeutic target in CRC patients.

Downregulation of the long non-coding RNA XLOC_010588 inhibits the invasion and migration of colorectal cancer

Long non-coding RNAs (lncRNAs) have emerged as major players in many biological and pathological processes; however, investigation into the function of lncRNAs in the development and progression of cancer is in its infancy. Therefore, clarification of the mechanism by which cancer-related lncRNAs function is of critical importance in research on tumorigenesis. It has been demonstrated that the lncRNA XLOC_010588 is expressed at a low level in cervical cancer, and that this has significant impact on the proliferation of cervical cancer cells. However, the expression pattern and functional roles of XLOC_010588 in colorectal cancer (CRC) remain unclear. In the present study, it was demonstrated that the expression of XLOC_010588 was significantly higher in CRC tissues when compared with that in adjacent normal tissues, and that XLOC_010588 was closely associated with metastasis and poor prognosis, thus indicating that XLOC_010588 may function as an oncogene. Additionally, downregulation of XLOC_010588 expression markedly inhibited the invasion and migration of CRC cells. Furthermore, it was demonstrated that XLOC_010588 may regulate the progression of CRC via the epithelial-mesenchymal transition (EMT) pathway. Notably, downregulation of XLOC_010588 inhibited the invasion and migration of CRC cells by regulating genes associated with EMT. Our findings revealed that XLOC_010588 may be considered as a novel potential diagnostic biomarker in CRC.

FEZF1-AS1/miR-107/ZNF312B axis facilitates progression and Warburg effect in pancreatic ductal adenocarcinoma

Long non-coding RNAs (lncRNAs) play a pivotal role in pathological processes. However, little information has been published regarding the underlying functions and mechanisms of lncRNAs in pancreatic ductal adenocarcinoma (PDAC). A novel lncRNA FEZF1-AS1 and its sense-cognate gene ZNF312B were found to be highly expressed in human PDAC tissues and cell lines, which is associated with disease progression and predicts clinical outcome in PDAC patients. Of note, bioinformatics analysis, luciferase assays and RNA immunoprecipitation assays indicated that FEZF1-AS1 may act as an endogenous sponge by competing for miR-107, thereby modulating the derepression of ZNF312B. Downregulation of FEZF1-AS1 or ZNF312B significantly inhibited proliferation, colony formation, migration, and invasion of PDAC cells in vitro, whereas the miR-107 inhibitor abrogated the effect of dow-regulation of FEZF1-AS1 or ZNF312B in reducing oncogenic capacities of PDAC cells. In addition, FEZF1-AS1/miR-107/ZNF312B axis-induced promotion of PDAC cells proliferation appeared to be mediated by modulation of the apoptosis and the G1-S checkpoint. Furthermore, downregulation of FEZF1-AS1 repressed tumor growth in mouse xenograft models. In particular, our results highlight the contribution of FEZF1-AS1/miR-107/ZNF312B axis to Warburg effect maintenance of PDAC cells. Collectively, our findings demonstrate that the FEZF1-AS1/miR-107/ZNF312B axis regulatory network might provide a potential new therapeutic strategy for PDAC.

Long non-coding RNA RAB11B-AS1 prevents osteosarcoma development and progression via its natural antisense transcript RAB11B

Long non-coding RNAs (lncRNAs) have been shown to exert essential roles in development and progression of tumors. Here we discovered a novel lncRNA, RAB11B antisense RNA (RAB11B-AS1), which is markedly down-regulated in human osteosarcoma (OS) and associated with OS metastasis and poor prognosis. We find that reduction of RAB11B-AS1 significantly facilitates proliferation, migration and invasiveness and prevents apoptosis of OS cells and results in lower sensitivity to cisplatin in these cells. In contrast, up-regulation of RAB11B-AS1 suppresses the aggressive behaviors of OS cells. Mechanistically, down-regulation of RAB11B-AS1 elevates its sense-cognate gene RAB11B expression at both mRNA and protein levels. RAB11B-AS1 expression correlates negatively with RAB11B expression in OS tissues. Luciferase reporter assay illuminated that RAB11B-AS1 regulates RAB11B expression through antisense pairing. Most importantly, all the effects of RAB11B-AS1 were abrogated by RAB11B down-regulation. Thus our findings revealed that lnc-RAB11B-AS1 prevents osteosarcoma development and progression via inhibiting RAB11B expression, indicating lnc-RAB11B-AS1 as a potential therapeutic target for osteosarcoma.

LincRNA FEZF1-AS1 contributes to the proliferation of LAD cells by silencing p57 expression

LincRNA FEZF1-AS1 has been identified to exert oncogenic functions in various biological processes of tumorigenesis. However, the function of FEZF1-AS1 in lung adenocarcinoma still remains unclear. Our findings revealed that FEZF1-AS1 was increased in lung adenocarcinoma tissues and cell lines and high level of FEZF1-AS1 was associated with poor prognosis of lung adenocarcinoma. Functional experiments and mechanistic investigations demonstrated that knockdown of FEZF1-AS1 significantly repressed proliferation through influencing the distribution of cell cycle. Besides, we also uncovered that FEZF1-AS1 could suppress p57 expression through recruiting EZH2 and LSD1 to the promoter of p57, thus influenced the cell cycle and proliferation. Collectively, our results suggested that FEZF1-AS1 was involved in the progression of lung adenocarcinoma and might be as a potential therapy target for human lung adenocarcinoma.

Long non-coding RNA LINC00959 predicts colorectal cancer patient prognosis and inhibits tumor progression

Long non-coding RNAs (lncRNAs) are increasingly implicated in tumorigenesis and cancer progression. This study focused on the relationship between the lncRNA LINC00959 and colorectal cancer (CRC). We found that LINC00959 expression was lower in CRC tissues than normal colorectal mucosae. High LINC00959 expression was negatively associated with TNM stage, distant metastasis, and lymphatic metastasis, and correlated with a better prognosis in 87 CRC cases. In vitro, LINC00959 knockdown enhanced colon cancer cell proliferation, invasion, and migration; upregulated N-cadherin and vimentin; and downregulated E-cadherin and Caspase-3. LINC00959 overexpression produced the opposite effects. These data suggest that LINC00959 inhibits tumor cell invasion and migration by suppressing epithelial-mesenchymal transition and promotes apoptosis through Caspase-3. LINC00959 may be a tumor suppressor and useful prognostic biomarker in CRC.

LncRNA FEZF1-AS1 enhances epithelial-mesenchymal transition (EMT) through suppressing E-cadherin and regulating WNT pathway in non-small cell lung cancer (NSCLC)

OBJECTIVE

Recent discoveries verify that long non-coding RNAs (lncRNAs) are important functional regulators involved in non-small cell lung cancer (NSCLC) progression. However, long non-coding RNA FEZF1-AS1 was not been investigated in NSCLC so for.

METHODS

We applied the quantitative real time polymerase chain reaction (qRT-PCR) assays to detect the expression of lncRNA FEZF1-AS1 in NSCLC tissues and adjacent normal tissues. Cell proliferation and invasion capacities were evaluated by MTT, colony formation, and cell invasion assays. Chromatin immunoprecipitation (ChIP) and RNA immunoprecipitation (RIP) methods demonstrated the association between lncRNA FEZF1-AS1 expression and E-cadherin. The relative protein expression levels were analyzed by western blot analysis.

RESULTS

LncRNA FEZF1-AS1 was significantly up-regulated in NSCLC tissues compared with adjacent normal tissues. Higher lncRNA FEZF1-AS1 expression levels associated with lymph node metastasis, poor differentiation grade and advanced TNM stage. In vitro, we revealed that down-regulation of lncRNA FEZF1-AS1 inhibited cell proliferation and cell invasion capacities in NSCLC. Moreover, down-regulation of lncRNA FEZF1-AS1 suppressed cell epithelial-mesenchymal transition (EMT) process by increasing the expression of E-cadherin and ZO-1, whereas, decreasing the expression of Slug, Twist and Vimentin in NSCLC cells. Furthermore, we demonstrated lncRNA FEZF1-AS1 could epigenetically repress the expression of E-cadherin via binding with LSD1 and EZH2 in NSCLC cells. We also revealed that knockdown of lncRNA FEZF1-AS1 suppressed Wnt/β-catenin signaling in NSCLC.

CONCLUSION

These results demonstrated that lncRNA FEZF1-AS1 could function as a tumor promoting regulator in NSCLC, which may provide a target of treatment in NSCLC.

MIER3 suppresses colorectal cancer progression by down-regulating Sp1, inhibiting epithelial-mesenchymal transition

Mesoderm induction early response 1, family member 3 (MIER3) has recently been identified as a potential cancer susceptibility gene. However, the expression pattern and the role of MIER3 in the progression of colorectal cancer (CRC) have not yet been well characterized. Here, we reported that MIER3 was significantly reduced in human primary colorectal cancer and was associated with CRC metastasis and poor prognosis. Moreover, the up-regulation of MIER3 expression significantly inhibited CRC cell proliferation, migration and invasion in vitro and repressed tumor growth and metastasis in vivo. In contrast, down-regulation of MIER3 could promote the aggressive behaviors of CRC cells. Furthermore, our study showed that MIER3 inhibited cell proliferation and invasion partially via reduction of Sp1 and subsequent suppression of epithelial-mesenchymal transition (EMT). In conclusion, our data suggested that MIER3 plays a potential tumor suppressor role in CRC progression and may be a potentially valuable clinical prognostic marker of this disease.

LncRNAs: the bridge linking RNA and colorectal cancer

Long noncoding RNAs (lncRNAs) are transcribed by genomic regions (exceeding 200 nucleotides in length) that do not encode proteins. While the exquisite regulation of lncRNA transcription can provide signals of malignant transformation, lncRNAs control pleiotropic cancer phenotypes through interactions with other cellular molecules including DNA, protein, and RNA. Recent studies have demonstrated that dysregulation of lncRNAs is influential in proliferation, angiogenesis, metastasis, invasion, apoptosis, stemness, and genome instability in colorectal cancer (CRC), with consequent clinical implications. In this review, we explicate the roles of different lncRNAs in CRC, and the potential implications for their clinical application.

Knockdown of lncRNA HNF1A-AS1 inhibits oncogenic phenotypes in colorectal carcinoma

Long non-coding RNAs (lncRNAs) have been demonstrated to serve important roles in the development and progression of cancer. Recently HNF1A antisense RNA 1 (HNF1A‑AS1), a lncRNA, has been reported as exhibiting a potential oncogenic role in the development of many types of cancer. However, the expression and the role of HNF1A‑AS1 in colorectal carcinoma (CRC) remains unclear. In the present study, the role of HNF1A‑AS1 in CRC was examined for the first time and its correlation with CRC cell biological behaviors was analyzed. The results demonstrated that HNF1A‑AS1 was distinctly upregulated in CRC tissues and associated with CRC metastasis to the lymph nodes. Reverse transcription‑quantitative polymerase chain reaction revealed that HNF1A‑AS1 was also upregulated in CRC cell lines and localized in the nucleus. In addition, knockdown of HNF1A‑AS1 expression notably inhibited CRC cell proliferation, migration, invasion and colony formation, and suppressed S‑phase entry in vitro. Taken together, these results suggested that HNF1A‑AS1 might serve as a promising prognostic marker for CRC tumorigenesis and progression.

The prognostic value of abnormally expressed lncRNAs in colorectal cancer: A meta-analysis

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent cancer type and the third leading cause of cancer-related deaths worldwide, it is urgently needed to discover a new marker for the progress of CRC. Many long noncoding RNAs (lncRNAs) have been reported to be abnormally expressed in CRC, and may be feasible as effective biomarkers and prognostic factors. The aim of this study was to identify the prognostic value of various lncRNAs in CRC.

METHODS

Pubmed, Web of Science, Embase and Cochrane Library were searched for potentially related studies. A total of 34 eligible studies including 30 on overall survival (OS), 7 on disease-free survival (DFS), 1 on relapse-free survival (RFS), 2 on disease-specific survival (DSS) and 29 on clinicopathological features were qualified from the databases.

RESULTS

The results showed that the expression levels of lncRNAs were significantly associated with poor OS (hazard ratio (HR) = 2.08, 95% confidence interval (CI) = 1.68-2.57, P<0.001, I2 = 70%), DFS (HR = 1.79, 95% CI = 1.54-2.08, P<0.001, I2 = 6%) and DSS (HR = 0.11, 95% CI = 0.02-0.54, P = 0.007, I2 = 14%). Subgroup analysis further showed that lncRNA transcription level was significantly associated with tumor differentiation (odds ratio (OR) = 0.51, 95% CI = 0.34-0.77, P = 0.001), lymph node metastasis (OR = 1.63, 95% CI = 1.23-2.17, P = 0.0007), distant metastasis (OR = 2.06, 95% CI = 1.29-3.30, P = 0.002), TNM stage (OR = 0.44, 95% CI = 0.32-0.62, P<0.001), tumor invasion depth (OR = 0.48, 95% CI = 0.39-0.60, P<0.001).

CONCLUSIONS

The meta-analysis demonstrated that abnormal lncRNA transcription level may serve as a promising indicator for prognostic of patients with CRC.

Intersecting transcriptomic profiling technologies and long non-coding RNA function in lung adenocarcinoma: discovery, mechanisms, and therapeutic applications

Previously thought of as junk transcripts and pseudogene remnants, long non-coding RNAs (lncRNAs) have come into their own over the last decade as an essential component of cellular activity, regulating a plethora of functions within multicellular organisms. lncRNAs are now known to participate in development, cellular homeostasis, immunological processes, and the development of disease. With the advent of next generation sequencing technology, hundreds of thousands of lncRNAs have been identified. However, movement beyond mere discovery to the understanding of molecular processes has been stymied by the complicated genomic structure, tissue-restricted expression, and diverse regulatory roles lncRNAs play. In this review, we will focus on lncRNAs involved in lung cancer, the most common cause of cancer-related death in the United States and worldwide. We will summarize their various methods of discovery, provide consensus rankings of deregulated lncRNAs in lung cancer, and describe in detail the limited functional analysis that has been undertaken so far.

Long noncoding RNA CRNDE stabilized by hnRNPUL2 accelerates cell proliferation and migration in colorectal carcinoma via activating Ras/MAPK signaling pathways

Recent studies have furthered our understanding of the function of long noncoding RNAs (lncRNAs) in numerous biological processes, including cancer. This study investigated the expression of a novel lncRNA, colorectal neoplasia differentially expressed (CRNDE), in colorectal carcinoma (CRC) tissues and cells by real-time RT-PCR and in situ hybridization, and its biological function using a series of in vitro and in vivo experiments to determine its potential as a prognostic marker and therapeutic target. CRNDE was found to be upregulated in primary CRC tissues and cells (P<0.05), and the upregulation of CRNDE expression is a powerful predictor of advanced TNM stage (P<0.05) and poor prognosis for CRC patients (P=0.002). The promoting effects of CRNDE on the cell proliferation, cell cycling and metastasis of CRC cells were confirmed both in vitro and in vivo by gain-of-function and loss-of-function experiments. Mechanistically, it was demonstrated that CRNDE could form a functional complex with heterogeneous nuclear ribonucleoprotein U-like 2 protein (hnRNPUL2) and direct the transport of hnRNPUL2 between the nucleus and cytoplasm. hnRNPUL2 that was accumulated in the cytoplasm could interact with CRNDE both physically and functionally, increasing the stability of CRNDE RNA. Moreover, gene expression profile data showed that CRNDE depletion in cells downregulated a series of genes involved in the Ras/mitogen-activated protein kinase signaling pathways. Collectively, these findings provide novel insights into the function and mechanism of lncRNA CRNDE in the pathogenesis of CRC and highlight its potential as a therapeutic target for CRC intervention.

Noncoding RNAs in the development, diagnosis, and prognosis of colorectal cancer

More than 90% of the human genome is actively transcribed, but less than 2% of the total genome encodes protein-coding RNA, and thus, noncoding RNA (ncRNA) is a major component of the human transcriptome. Recently, ncRNA was demonstrated to play important roles in multiple biological processes by directly or indirectly interfering with gene expression, and the dysregulation of ncRNA is associated with a variety of diseases, including cancer. In this review, we summarize the function and mechanism of miRNA, long intergenic ncRNA, and some other types of ncRNAs, such as small nucleolar RNA, circular ncRNA, pseudogene RNA, and even protein-coding mRNA, in the progression of colorectal cancer (CRC). We also presented their clinical application in the diagnosis and prognosis of CRC. The summary of the current state of ncRNA in CRC will contribute to our understanding of the complex processes of CRC initiation and development and will help in the discovery of novel biomarkers and therapeutic targets for CRC diagnosis and treatment.

Prognostic and clinicopathological significance of long noncoding RNA H19 overexpression in human solid tumors: evidence from a meta-analysis

BACKGROUND

Many studies have reported that the expression level of lncRNA H19 was increased in various tumors. LncRNA H19 may play a significant role in cancer occurrence and development. An increased level of H19 was also associated with poor clinical outcomes of cancer patients.

RESULTS

12 eligible studies were screened, with a total of 1437 cancer patients. From the results of meta-analysis, as for prognosis, the patients with high expression of lncRNA H19 were shorter in OS (HR=1.08, 95% CI: 1.05-1.12). Statistical significance was also showed in subgroup meta-analysis stratified by the cancer type, analysis type and sample size. In addition, the patients detected with high H19 expression may be poorer in DFS (HR=1.27; 95% CI = 0.97-1.56). As for clinicopathology, it showed that increased H19 was related to poor histological grades (OR=2.31, 95% CI: 1.12-4.75), positive lymph node metastasis (OR=2.29, 95 % CI: 1.21-4.34) and advanced clinical stage (OR=4.83, 95% CI: 3.16-7.39).

MATERIALS AND METHODS

Eligible studies were collected by retrieving keywords in PubMed, Web of Science, Embase, CNKI and Wanfang database, from 1966 to April 23, 2016. This quantitative meta-analysis was performed with Stata SE12.0 and RevMan5.3 software. It aimed to explore the association between H19 expression level and prognosis and clinicopathology.

CONCLUSIONS

LncRNA-H19 may be a novel molecular marker for predicting solid tumors. It can also be a predictive factor of clinicopathological features in various cancers. Further studies are needed to verify the clinical utility of H19 in human cancers.

Mining, Validation, and Clinical Significance of Colorectal Cancer (CRC)-Associated lncRNAs

Background

Colorectal cancer (CRC) is one of the deadliest tumours, but its pathogenesis remains unclear. The involvement of differentially expressed long non-coding RNAs (lncRNAs) in CRC tumorigenesis makes them suitable tumour biomarkers.

Methods/Findings

Here, we screened 150 cases of CRC and 85 cases of paracancerous tissues in the GEO database for differentially expressed lncRNAs. The levels of lncRNA candidates in 84 CRC and paracancerous tissue samples were validated by qRT-PCR and their clinical significance was analyzed. We identified 15 lncRNAs with differential expression in CRC tumours; among them, AK098081 was significantly up-regulated, whereas AK025209, BC040303, BC037331, AK026659, and CR749831 were down-regulated in CRC. In a receiver operating characteristic curve analysis, the area under the curve for the six lncRNAs was 0.914. High expression of AK098081 and low expression of BC040303, CR749831, and BC037331 indicated poor CRC differentiation. CRC patients with lymph node metastasis had lower expression of BC037331. In addition, the group with high AK098081 expression presented significantly lower overall survival and disease-free survival rates than the low-expression group, confirming AK098081 as an independent risk factor for CRC patients.

Conclusion/Significance

In conclusion, we have identified multiple CRC-associated lncRNAs from microarray expression profiles that can serve as novel biomarkers for the diagnosis and prognosis of CRC.

Increased long noncoding RNA SNHG20 predicts poor prognosis in colorectal cancer

Background

Long noncoding RNAs (lncRNAs) have been suggested to be involved in the development and progression of malignancies. However, the investigation of small nucleolar RNA host gene 20 (SNHG20) on cancer progression remains unknown. The present study aims to explore the clinical significance of SNHG20 and its potential molecular mechanism in colorectal cancer (CRC).

Methods

Quantitative real-time PCR (qRT-PCR) was used to measure the SNHG20 expression in a total of 107 CRC tissues and CRC cell lines. Loss of function approach was employed to explore the biological roles of SNHG20 in vitro. Its potential molecular mechanism was further verified by western blotting and qRT-PCR.

Results

The results suggested that SNHG20 expression was significantly upregulated in CRC tissues compared to corresponding normal tissues from 107 CRC patients. High expression of SNHG20 was remarkably associated with advanced TNM stage in patients with CRC. Multivariate analyses unraveled that SNHG20 expression was an independent prognostic factor for overall survival in CRC patients. Further functional assays revealed that knockdown of SNHG20 suppressed cell proliferation, invasion and migration, and cell cycle progression in CRC cells. Moreover, SNHG20 regulated cell growth through modulation of a series of cell cycle-associated genes.

Conclusions

Our findings suggest that dysregulation of SNHG20 participates in CRC progression and may serve as a potential therapeutic target in CRC patients.

Long noncoding RNA XIST acts as an oncogene in non-small cell lung cancer by epigenetically repressing KLF2 expression

Recently, long noncoding RNAs (lncRNAs) have been identified as critical regulators in numerous types of cancers, including non-small cell lung cancer (NSCLC). X inactivate-specific transcript (XIST) has been found to be up-regulated and acts as an oncogene in gastric cancer and hepatocellular carcinoma, but little is known about its expression pattern, biological function and underlying mechanism in NSCLC. Here, we identified XIST as an oncogenic lncRNA by driving tumorigenesis in NSCLC. We found that XIST is over-expressed in NSCLC, and its increased level is associated with shorter survival and poorer prognosis. Knockdown of XIST impaired NSCLC cells proliferation, migration and invasion in vitro, and repressed the tumorigenicity of NSCLC cells in vivo. Mechanistically, RNA immune-precipitation (RIP) and RNA pull-down experiment demonstrated that XIST could simultaneously interact with EZH2 to suppress transcription of its potential target KLF2. Additionally, rescue experiments revealed that XIST's oncogenic functions were partly depending on silencing KLF2 expression. Collectively, our findings expound how XIST over-expression endows an oncogenic function in NSCLC.

Long noncoding RNA HULC promotes colorectal carcinoma progression through epigenetically repressing NKD2 expression

Recently, long noncoding RNAs (lncRNAs) have been emerged as crucial regulators of human diseases and prognostic markers in numerous of cancers, including colorectal carcinoma (CRC). Here, we identified an oncogenetic lncRNA HULC, which may promote colorectal tumorigenesis. HULC has been found to be up-regulated and acts as oncogene in gastric cancer and hepatocellular carcinoma, but its expression pattern, biological function and underlying mechanism in CRC is still undetermined. Here, we reported that HULC expression is also over-expressed in CRC, and its increased level is associated with poor prognosis and shorter survival. Knockdown of HULC impaired CRC cells proliferation, migration and invasion, and facilitated cell apoptosis in vitro, and inhibited tumorigenicity of CRC cells in vivo. Mechanistically, RNA immunoprecipitation (RIP) and RNA pull-down experiment demonstrated that HULC could simultaneously interact with EZH2 to repress underlying targets NKD2 transcription. In addition, rescue experiments determined that HULC oncogenic function is partly dependent on repressing NKD2. Taken together, our findings expound how HULC over-expression endows an oncogenic function in CRC.

Long Non-Coding RNAs As Potential Novel Prognostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is the fourth most common cause of death worldwide. Surgery is usually the first line of treatment for patients with CRC but many tumors with similar histopathological features show significantly different clinical outcomes. The discovery of robust prognostic biomarkers in patients with CRC is imperative to achieve more effective treatment strategies and improve patient's care. Recent progress in next generation sequencing methods and transcriptome analysis has revealed that a much larger part of the genome is transcribed into RNA than previously assumed. Collectively referred to as non-coding RNAs (ncRNAs), some of these RNA molecules such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) have been shown to be altered and to play critical roles in tumor biology. This discovery leads to exciting possibilities for personalized cancer diagnosis, and therapy. Many lncRNAs are tissue and cancer-type specific and have already revealed to be useful as prognostic markers. In this review, we focus on recent findings concerning aberrant expression of lncRNAs in CRC tumors and emphasize their prognostic potential in CRC. Further studies focused on the mechanisms of action of lncRNAs will contribute to the development of novel biomarkers for diagnosis and disease progression.