Overexpression of the long non-coding RNA, linc-UBC1, is associated with poor prognosis and facilitates cell proliferation, migration, and invasion in colorectal cancer

The prognostic significance of LncRNA BLACAT1 overexpression in various tumors: a meta-analysis

Objective

Recent studies have revealed increasing evidence that the long non-coding RNA bladder cancer associated transcript 1 (LncRNA BLACAT1) plays an essential role in the emergence of different malignancies. This meta-analysis aimed to evaluate the prognostic significance of LncRNA BLACAT1 in various cancers.

Methods

Six electronic databases (PubMed, Embase, Medline, Web of Science, China National Knowledge Infrastructure (CNKI), and the Chinese WanFang database) were comprehensively searched for relevant studies. The analysis of overall survival (OS) and clinicopathological characteristics was conducted.

Results

Nineteen studies with 1,559 patients were eventually eligible to be included in this meta-analysis. High expression level of LncRNA BLACAT1 was identified to be linked with shorter OS (HR: 2.02, 95% CI: 1.66-2.46, p < 0.001) and PFS (HR: 2.424, 95% CI: 1.827-3.020, p < 0.001) in cancer patients as opposed to low expression levels. Subgroup analysis showed that analysis model (multivariate or univariate), cut-off value (mean or median), sample size (more or fewer than 100), and cancer type had little effect on OS in multiple tumors. Moreover, high LncRNA BLACAT1 expression was associated with positive lymph node metastasis (HR: 2.29, 95% CI: 1.66-3.16, p < 0.00001), advanced clinical stage (HR: 2.29, 95% CI: 1.65-3.19, p < 0.00001) and worse differentiation status (HR: 0.58, 95% CI: 0.37-0.92, p = 0.02), compared to low LncRNA BLACAT1 expression.

Conclusion

The findings highlight that high LncRNA BLACAT1 expression might be detrimental and induce a worse prognosis for cancer patients.

Urinary BLACAT1 as a non-invasive biomarker for bladder cancer

BACKGROUND

Bladder cancer (BC) is recorded as the fifth most common cancer worldwide with high morbidity and mortality. The most urgent problem in BCs is the high recurrence rate as two-thirds of non-muscle-invasive bladder cancer (NMIBC) will develop into muscle-invasive bladder cancer (MIBC), which retains a feature of rapid progress and metastasis. In addition, only a limited number of biomarkers are available for diagnosing BC compared to other cancers. Hence, finding sensitive and specific biomarkers for predicting the diagnosis and prognosis of patients with BC is critically needed. Therefore, this study aimed to determine the expression and clinical significance of urinary lncRNA BLACAT1 as a non-invasively diagnostic and prognostic biomarker to detect and differentiate BCs stages.

METHODS AND RESULTS

The expression levels of urinary BLACAT1 were detected by qRT-PCR assay in seventy (70) BC patients with different TNM grades (T0-T3) and twelve (12) healthy subjects as control. BLACAT1 was downregulated in superficial stages (T0 = 0.09 ± 0.02 and T1 = 0.5 ± 0.1) compared to healthy control. Furthermore, in the invasive stages, its levels started to elevate in the T2 stage (1.2 ± 0. 2), and higher levels were detected in the T3 stage with a mean value of (5.2 ± 0.6). This elevation was positively correlated with disease progression. Therefore, BLACAT1 can differentiate between metastatic and non-metastatic stages of BCs. Furthermore, its predictive values are not like to be influenced by schistosomal infection.

CONCLUSIONS

Upregulation of BLACAT1 in invasive stages predicted an unfavorable prognosis for patients with BCs, as it contributes to the migration and metastasis of BCs. Therefore, we can conclude that urinary BLACAT1 may be considered a non-invasive promising metastatic biomarker for BCs.

Sodium Selenite Regulates the Proliferation and Apoptosis of Gastric Cancer Cells by Suppressing the Expression of LncRNA HOXB-AS1

Gastric carcinoma has a high incidence, accounting for approximately 6% of all cancers worldwide. The in vivo antitumor effect of sodium selenite on gastric carcinoma has been demonstrated. This study therefore aimed to further explore its targets in gastric cancer in vitro and elucidate its mechanism of action. The effects of inorganic sodium selenite (Na2SeO3) on apoptosis, proliferation, and invasion of gastric cancer cells were investigated, and the interaction between Na2SeO3 and expression of long noncoding RNA homeobox B cluster antisense RNA 1 (HOXB-AS1) was investigated to elucidate the specific mechanism of action of selenium on gastric cancer cell proliferation through regulation of HOXB-AS1. Na2SeO3 downregulated the expression of HOXB-AS1 in the human gastric cancer (HGC) cell lines, HGC-27, NCI-N87, and KATO III cells, while inhibiting their proliferation and invasion and inducing apoptosis. The upregulation of HOXB-AS1 produced the opposite results. Na2SeO3 was used to stimulate HGC-27 cells, which caused HOXB-AS1 overexpression. The cell counting kit-8 (CCK-8) assay revealed a decrease in cell proliferation, while western blotting, flow cytometry, and transwell migration assays showed the expression of apoptosis-related (Bad, Bcl-2, and cleaved-caspase-3) and invasion-related (MMP2, E-cadherin, and N-cadherin) proteins, indicating increased apoptosis and decreased invasion. We therefore conclude that Na2SeO3 inhibits the malignant progression of gastric cancer by downregulating the expression of HOXB-AS1 and thus could be used as a potential drug for its treatment.

LINC00511 knockdown suppresses glioma cell malignant progression through miR-15a-5p/AEBP1 axis

BACKGROUND

A strong relationship between long intergenic non-protein coding RNA 511 (LINC00511) and glioma has been previously reported but the mechanism of LINC00511 in glioma is yet to be determined. This study examined the mechanism of LINC00511 in glioma.

METHODS

The expression of LINC00511 in glioma was determined by bioinformatics analysis and real-time quantitative PCR (RT-qPCR) analysis. The target relationship between genes was predicted by starBase, TargetScan, and was verified by dual-luciferase. Subsequently, siRNA targeting LINC00511 (siLINC00511) and miR-15a-5p mimic were transfected into glioma cells to examine the effect on biological characteristics using cell counting kit-8, clone formation, flow cytometry, wound-healing, and transwell. MiR-15a-5p inhibitor and AEBP1 were used for in vitro rescue experiments, and tumorigenesis assay and immunohistochemical assays were performed for in vivo experiments. Epithelial-mesenchymal transition (EMT) and p65 phosphorylation were examined by Western blot.

RESULTS

LINC00511 was predicted and verified to be up-regulated in glioma. SiLINC00511 suppressed cell viability, proliferation, migration and invasion, accelerated apoptosis of glioma cells. Mechanically, siLINC00511 promoted E-cadherin expression but suppressed N-cadherin and Snail expressions. MiR-15a-5p bound to LINC00511, and miR-15a-5p inhibitor partially reversed the effect and regulation of siLINC00511 on glioma cells. AEBP1, a target gene of miR-15a-5p, could activate p65 phosphorylation to promote EMT protein expression and partially reverse the inhibitory effect of miR-15a-5p mimic on the malignant phenotype of glioma cells. SiLINC00511 inhibited tumor growth, down-regulated miR-15a-5p expression and up-regulated AEBP1 and Ki67 expressions in vivo.

CONCLUSION

LINC00511 knockdown inhibits glioma cell progression via miR-15a-5p/AEBP1 axis.

The Emerging Landscape of Long Non-Coding RNAs in Colorectal Cancer Metastasis

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers, with extremely high rates of morbidity and mortality. The main cause of death in CRC is distant metastasis; it affects patient prognosis and survival and is one of the key challenges in the treatment of CRC. Long non-coding RNAs (lncRNAs) are a group of non-coding RNA molecules with more than 200 nucleotides. Abnormal lncRNA expression is closely related to the occurrence and progression of several diseases, including cancer. Recent studies have shown that numerous lncRNAs play pivotal roles in the CRC metastasis, and reversing the expression of these lncRNAs through artificial means can reduce the malignant phenotype of metastatic CRC to some extent. This review summarizes the major mechanisms of lncRNAs in CRC metastasis and proposes lncRNAs as potential therapeutic targets for CRC and molecular markers for early diagnosis.

A systematic review and meta-analysis of long noncoding RNA linc-UBC1 expression and prognosis and clinicopathological phenotypes in human cancers

According to previous studies, linc-UBC1 is abnormally expressed in various human tumours. Nonetheless, the clinical significance and mechanism of linc-UBC1 in cancer remains unclear. In our present analysis, we wanted to explore the specific role of linc-UBC1 in malignant tumours by integrating all of the relevant literature and subsequently elucidating the relationship between linc-UBC1 expression level and clinical characteristics of cancers. An elaborate database search of PubMed, Embase, Wanfang Data, Web of Science, Ovid, Medline, Cochrane Library and PMC was carried out up to 8 August 2019. We further applied the pooled odds ratio (OR) and hazard ratio (HR) to evaluate OS. After filtering by strict criteria, 11 studies containing 1017 cases were included in this analysis. Our results implied that high expression of linc-UBC1 was obviously related to poor OS in cancer (HR =1.735, 95% 1.348-2.235, p < .001 random effects model). Analogously, the data revealed that high expression of linc-UBC1 was highly correlated with lymph node metastasis (OR = 2.912, 95% CI: 2.056-4.125, p < .001 fix effects model) and high tumour stage (OR = 2.678, 95% CI: 1.859-3.857, p < .001 fix effects model). In summary, linc-UBC1 overexpression is associated with poor OS and advanced tumour stage and could be used as a novel prognostic biomarker in various cancers.

Lung Carcinoma Cells Secrete Exosomal MALAT1 to Inhibit Dendritic Cell Phagocytosis, Inflammatory Response, Costimulatory Molecule Expression and Promote Dendritic Cell Autophagy via AKT/mTOR Pathway

Objective

To investigate the potential mechanism underlying the effect of lung carcinoma cell-derived exosomes on dendritic cell function.

Materials and Methods

C57BL/6 (B6) mice were randomly divided into five groups: control, dendritic cell (DC), DC-NC, DC-siMALAT1, and siMALAT1. Tumor cell proliferation was measured by Ki-67 staining. LLC cells were divided into control, NC, and si-MALAT1 groups, and exosomes secreted by each group were labeled as PEX, PEXN, and PEX-si, respectively. Exosomes and autophagic vacuoles were observed by transmission electron microscopy. MALAT1 expression in LLC, A549, and Beas-2b cells was examined by RT-PCR. The expression of IFN-γ, IL-12, IL-10, and TGF-β was observed by Elisa assay. Flow cytometry was used to observe the phagocytic function of DCs, costimulatory molecule expression, and T cell proliferation and differentiation. The protein expression of p-AKT, AKT, p-mTOR, mTOR, ALIX, TSG101, and CD63 was detected by Western blot.

Results

Compared with Beas-2b cells, MALAT1 expression was significantly increased in both LLC and A549 cells and in their secreted exosomes, and LLC cells showed the highest expression of MALAT1 (P < 0.05). Tumor cell proliferation and tumor volume were significantly decreased in the siMALAT1 and DC-siMALAT1 groups compared to those in the control group. DC phagocytosis, inflammatory response, costimulatory molecule expression, and T cell proliferation in the siMALAT1 and PEX-si groups were significantly enhanced (P < 0.05), while DC autophagy and T cell differentiation were reduced (P < 0.05). The levels of p-AKT, AKT, p-mTOR, and mTOR in the PEX and PEXN groups were increased compared with those in the control group, while those in the siMALAT1 and PEX-si groups were significantly decreased (P < 0.05).

Conclusion

Inhibition of MALAT1 expression in LLC-derived exosomes promoted DC function and T cell proliferation and suppressed DC autophagy and T cell differentiation, suggesting that MALAT1 inhibition may be a potential strategy for the clinical treatment of lung cancer.

Target Enrichment Enables the Discovery of lncRNAs with Somatic Mutations or Altered Expression in Paraffin-Embedded Colorectal Cancer Samples

Simple Summary

Alterations in long noncoding RNAs and their mutations have been increasingly recognized in tumorogenesis and cancer progression awakening especial interest as potential novel cancer biomarkers and therapeutic targets. The use of adjuvant chemotherapy in stage II colorectal cancer patients is challenging, and new biomarkers are required to identify patients with high probability of relapse. We focused on translational potential of non-coding RNAs in colorectal cancer. In this study, we aim to validate a new tool which couples target enrichment and RNAseq for transcriptomics studies of lncRNAs in formalin-fixed paraffin embedded (FFPE) tissue samples. Our results show that this new approach efficiently detects lncRNAs and differences in their expression between healthy and tumor FFPE tissues, as well as somatic mutations in expressed lncRNAs, identifying novel lncRNAs as potential candidates for colorectal cancer. This new approach could represent a promising avenue that would reduce costs and enable more efficient translational research.

Abstract

Long non-coding RNAs (lncRNAs) play important roles in cancer and are potential new biomarkers or targets for therapy. However, given the low and tissue-specific expression of lncRNAs, linking these molecules to particular cancer types and processes through transcriptional profiling is challenging. Formalin-fixed, paraffin-embedded (FFPE) tissues are abundant resources for research but are prone to nucleic acid degradation, thereby complicating the study of lncRNAs. Here, we designed and validated a probe-based enrichment strategy to efficiently profile lncRNA expression in FFPE samples, and we applied it for the detection of lncRNAs associated with colorectal cancer (CRC). Our approach efficiently enriched targeted lncRNAs from FFPE samples, while preserving their relative abundance, and enabled the detection of tumor-specific mutations. We identified 379 lncRNAs differentially expressed between CRC tumors and matched healthy tissues and found tumor-specific lncRNA variants. Our results show that numerous lncRNAs are differentially expressed and/or accumulate variants in CRC tumors, thereby suggesting a role in CRC progression. More generally, our approach unlocks the study of lncRNAs in FFPE samples, thus enabling the retrospective use of abundant, well documented material available in hospital biobanks.

Long Non-Coding RNA BLACAT1 in Human Cancers

Long non-coding RNAs (lncRNAs) are a cluster of RNAs with more than 200 nucleotides in length, which lack protein-coding capacity. They are important regulators of numerous cellular processes, including gene transcription, translation, and posttranslational modification, especially in tumor initiation and progression. Aberrant expression of lncRNA bladder cancer-associated transcript 1 (BLACAT1) has been reported in various human cancers and was usually associated with unfavorable prognosis. Previous studies have revealed that dysregulation of BLACAT1 could promote the proliferation and metastasis of cancer cells. In this review, we summarize the present understanding of the functions and underlying mechanisms of BLACAT1 in the occurrence and development of various human cancers and discuss the roles of this lncRNA in cancers, including its promising application as a prognostic biomarker or a novel therapeutic target for malignancies.

A prognostic five long-noncoding RNA signature for patients with rectal cancer

This study aimed to identify prognostic long noncoding RNAs (lncRNAs) signature for predicting the prognosis of patients with rectal cancer. LncRNA-sequencing data and clinicopathological data of patients with rectal cancer were retrieved from The Cancer Genome Atlas database. Univariate and multivariate Cox proportional hazards regression analysis, the least absolute shrinkage, and selection operator analysis and the Kaplan-Meier curve method were employed to identify prognostic lncRNAs and construct multi-lncRNA signature. Finally, five lncRNAs (AC079789.1, AC106900.2, AL121987.1, AP004609.1, and LINC02163) were identified to construct a five-lncRNA signature. According to the five-lncRNA signature, patients with rectal cancer were divided into a high-risk group and low-risk group. Patients with rectal cancer had significantly poorer overall survival in the high-risk group than in the low-risk group. We used a time-dependent receiver operating characteristic curve to assess the power of the five-lncRNA signature by calculating the area under the curve (AUC). The AUCs for predicting 3-year survival and 5-year survival were 0.742 and 0.935, respectively, which indicated a good performance of the five-lncRNA signature. The five-lncRNA signature was independently associated with the prognosis of patients with rectal cancer through using univariate and multivariate Cox regression analysis. The biological function of the five lncRNAs was enriched in some cancer-related biological processes and pathways by performing functional enrichment analysis of their correlated protein-coding genes. In conclusion, we developed a five-lncRNA signature as a potential indicator for rectal cancer.

The Construction and Comprehensive Prognostic Analysis of the LncRNA-Associated Competitive Endogenous RNAs Network in Colorectal Cancer

Competing endogenous RNAs (ceRNAs) are a newly proposed RNA interaction mechanism that has been associated with the tumorigenesis, metastasis, diagnosis, and predicting survival of various cancers. In this study, we constructed a ceRNA network in colorectal cancer (CRC). Then, we sought to develop and validate a composite clinicopathologic–genomic nomogram using The Cancer Genome Atlas (TCGA) database. To construct the ceRNA network in CRC, we analyzed the mRNAseq, miRNAseq data, and clinical information from TCGA database. LncRNA, miRNA, and mRNA signatures were identified to construct risk score as independent indicators of the prognostic value in CRC patients. A composite clinicopathologic–genomic nomogram was developed to predict the overall survival (OS). One hundred sixty-one CRC-specific lncRNAs, 97 miRNAs, and 161 mRNAs were identified to construct the ceRNA network. Multivariate Cox proportional hazards regression analysis indicated that nine-lncRNA signatures, eight-miRNA signatures, and five-mRNA signatures showed a significant prognostic value for CRC. Furthermore, a clinicopathologic–genomic nomogram was constructed in the primary cohort, which performed well in both the primary and validation sets. This study presents a nomogram that incorporates the CRC-specific ceRNA expression profile, clinical features, and pathological factors, which demonstrate its excellent differentiation and risk stratification in predicting OS in CRC patients.

Biological and clinical relevance of metastasis-associated long noncoding RNAs in esophageal squamous cell carcinoma: A systematic review

Esophageal squamous cell carcinoma (ESCC) is a foremost cancer-related death worldwide owing to rapid metastasis and poor prognosis. Metastasis, as the most important reason for death, is biologically a multifaceted process involving a range of cell signaling pathways. Long noncoding RNAs (lncRNAs), as transcriptional regulators, can regulate numerous genomic processes and cellular processes such as cell proliferation, migration, and invasion. LncRNAs have also been shown to involve in/regulate the cancer metastasis-related signaling pathways. Hence, they have increasingly been brought to international attention in molecular oncology research. A number of researchers have attempted to reveal the biological and clinical relevance of lncRNAs in ESCC tumourigenesis and metastasis. The aberrant expression of these molecules in ESCC has regularly been reported to involve in various cellular processes and clinical features, including diagnosis, prognosis, and therapeutic responses. Here, we especially consider the pathways in which lncRNAs act as metastasis-mediated effectors, mainly by interacting with epithelial-mesenchymal transition-associated factors. We review the biological roles of lncRNAs through involving in ESCC metastasis as well as the clinical significance of the metastasis-related lncRNAs in cancer diagnosis and prognosis.

LncRNAs as potential diagnostic and prognostic biomarkers in gastric cancer: A novel approach to personalized medicine

Gastric cancer is the third leading cause of cancer death with 5-year survival rate of about 30-35%. Since early detection is associated with decreased mortality, identification of novel biomarkers for early diagnosis and proper management of patients with the best response to therapy is urgently needed. Long noncoding RNAs (lncRNAs) due to their high specificity, easy accessibility in a noninvasive manner, as well as their aberrant expression under different pathological and physiological conditions, have received a great attention as potential diagnostic, prognostic, or predictive biomarkers. They may also serve as targets for treating gastric cancer. In this review, we highlighted the role of lncRNAs as tumor suppressors or oncogenes that make them potential biomarkers for the diagnosis and prognosis of gastric cancer. Relatively, lncRNAs such as H19, HOTAIR, UCA1, PVT1, tissue differentiation-inducing nonprotein coding, and LINC00152 could be potential diagnostic and prognostic markers in patients with gastric cancer. Also, the impact of lncRNAs such as ecCEBPA, MLK7-AS1, TUG1, HOXA11-AS, GAPLINC, LEIGC, multidrug resistance-related and upregulated lncRNA, PVT1 on gastric cancer epigenetic and drug resistance as well as their potential as therapeutic targets for personalized medicine was discussed.

Diagnostic and prognostic potential of tissue and circulating long non-coding RNAs in colorectal tumors

Long non-coding RNAs (lncRNAs) are members of the non-protein coding RNA family longer than 200 nucleotides. They participate in the regulation of gene and protein expression influencing apoptosis, cell proliferation and immune responses, thereby playing a critical role in the development and progression of various cancers, including colorectal cancer (CRC). As CRC is one of the most frequently diagnosed malignancies worldwide with high mortality, its screening and early detection are crucial, so the identification of disease-specific biomarkers is necessary. LncRNAs are promising candidates as they are involved in carcinogenesis, and certain lncRNAs (e.g., CCAT1, CRNDE, CRCAL1-4) show altered expression in adenomas, making them potential early diagnostic markers. In addition to being useful as tissue-specific markers, analysis of circulating lncRNAs (e.g., CCAT1, CCAT2, BLACAT1, CRNDE, NEAT1, UCA1) in peripheral blood offers the possibility to establish minimally invasive, liquid biopsy-based diagnostic tests. This review article aims to describe the origin, structure, and functions of lncRNAs and to discuss their contribution to CRC development. Moreover, our purpose is to summarise lncRNAs showing altered expression levels during tumor formation in both colon tissue and plasma/serum samples and to demonstrate their clinical implications as diagnostic or prognostic biomarkers for CRC.

LINC00957 Acted as Prognostic Marker Was Associated With Fluorouracil Resistance in Human Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent digestive tumors in China. Recent studies indicate that long intergenic non-coding RNAs (lincRNAs) play a crucial role in predicting survival for CRC patients. However, the novel lincRNA, LINC00957, is largely unclear in CRC. The purpose of the current study was to determine LINC00957 expression, assess its the clinical significance and explore the potential mechanism in CRC. The qRT-PCR was used to quantify the expression levels of LINC00957 in tissues and cell lines. Our research revealed that LINC00957 was significantly higher expression in CRC. In addition, the LINC00957 expression was associated with TNM stage and chemotherapy outcome, but age, gender, tumor size, histological grade, primary tumor location. CRC patients with high LINC00957 expression level showed poor overall survival (P = 0.002). Multivariate survival analysis indicated that LINC00957 was a prognostic factor for CRC patients (P = 0.010). Mechanically, inhibition of LINC00957 expression reversed 5-FU resistance by down-regulating P-gP. In summary, our study indicated that this novel lncRNA expression signature might be a useful biomarker of the prognosis and therapeutic target for CRC patients.

LncRNA BLACAT1 May Serve as a Prognostic Predictor in Cancer: Evidence from a Meta-Analysis

Background

As a newly discovered lncRNA, bladder cancer-associated transcript 1 (BLACAT1) has been reported to correlate with poor clinical outcomes in several different cancers. This study aimed to evaluate its generalized predictive value for cancer prognosis.

Materials and Methods

We thoroughly searched PubMed, Embase, and Web of Science databases for eligible studies published until November 11, 2018, in which the relationship between BLACAT1 expression and cancer prognosis was explored. The analyses were performed using Review Manager Version 5.3 and Stata SE 12.0. The primary endpoints included overall survival (OS), pathological characteristics (TNM stage and tumor grade), lymph node metastasis (LNM), and distant metastasis.

Results

Ten studies containing 861 patients with 7 different cancerous diseases were eventually included. The results demonstrated that patients with high lncRNA BLACAT1 expression had a significantly shorter OS (HR: 1.82, 95% CI: 1.44-2.30, p < 0.00001) than patients with low lncRNA BLACAT1 expression. Moreover, elevated BLACAT1 expression was significantly associated with advanced TNM stage (OR: 2.29, 95% CI: 1.15-4.56, p = 0.005), high tumor grade (OR: 1.67, 95% CI: 1.11-2.53, p = 0.01), and lymph node metastasis (OR: 2.53, 95% CI: 1.80-3.57, p < 0.00001). Meanwhile, the expression of BLACAT1 had no significant association with age (p = 0.92), gender (p = 0.55), and smoking (p = 0.62).

Conclusion

High expression of lncRNA BLACAT1 may predict a poor prognosis in OS, TNM stage, tumor grade, and LNM. Its predictive roles were not significantly affected by age, gender, or smoking. Therefore, lncRNA BLACAT1 may serve as a promising predictor in cancer prognosis.

BLACAT1 predicts poor prognosis and serves as oncogenic lncRNA in small-cell lung cancer

Bladder cancer-associated transcript 1 (BLACAT1) is a novel identified long noncoding RNA (lncRNA) in bladder cancer, and has been suggested to function as an oncogenic lncRNA in several types of human cancer. However, its involvement in the progression of small-cell lung cancer (SCLC) remained unknown. The aim of our study was to investigate the clinical value and biological function in SCLC. In our results, BLACAT1 expression was increased in SCLC tissues and cell lines compared with paired adjacent normal tissues and bronchial epithelial cell lines, respectively. In addition, BLACAT1 high-expression was obviously associated with advanced clinical stage, large tumor size, more lymph node metastasis, present distant metastasis, and poor prognosis. Furthermore, multivariate analysis indicated that high-expression of BLACAT1 acted as an independent poor prognostic factor for overall survival in SCLC cases. The loss-of-function studies suggested that of BLACAT1 suppressed SCLC cell proliferation, migration, and invasion, and induced G0/G1 phase arrest. In conclusion, BLACAT1 is associated with the malignant status and prognosis in patients with SCLC, and functions as an oncogenic lncRNA in regulating cell proliferation and motility, suggesting BLACAT1 may act as a potential target for SCLC prevention and treatment.

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 non‑coding RNA 00152 functions as a competing endogenous RNA to regulate NRP1 expression by sponging with miRNA‑206 in colorectal cancer

Colorectal cancer (CRC) is the third most common type of cancer; however, the molecular mechanisms underlying colorectal tumor metastasis and growth remain elusive. Recently, accumulating evidence has indicated that long non‑coding RNAs (lncRNAs) play a critical role in CRC progression and metastasis; however, the biological role and clinical significance of lncRNA 00152 (lnc00152) in CRC remains largely unknown. Thus, in this study, lnc00152 expression was measured in 80 human CRC tissue samples, 40 non‑cancerous tissue samples, and 3 CRC cell lines (SW480, SW620 and LoVo) using RT‑qPCR. We examined the effects of lnc00152 on CRC cells following transfection with lnc00152 overexpression plasmid or respective siRNA in vitro and in vivo. Luciferase assays revealed the mechanism driving competitive endogenous RNA (ceRNA). We identified that lnc00152 was aberrantly overexpressed in colorectal tumors and cancer cells and that lnc00152 was modulated by miRNA‑206. lnc00152 overexpression enhanced the proliferative and invasive ability of CRC cells in vitro, promoted tumor growth in vivo, and was associated with the shorter overall survival of patients with CRC. In addition, lnc00152 overexpression promoted epithelial-mesenchymal transition (EMT) and increased neuropilin‑1 (NRP1) expression in the CRC cells. By contrast, lnc00152 silencing exerted a counteractive effect. Collectively, these findings demonstrate the critical role of lnc00152 in tumor growth and progression in CRC, and identify a novel therapeutic target associated with CRC development and progression.

Comprehensive analysis of a long noncoding RNA-associated competing endogenous RNA network in colorectal cancer

Purpose

This study was aimed to develop a lncRNA-associated competing endogenous RNA (ceRNA) network to provide further understanding of the ceRNA regulatory mechanism and pathogenesis in colorectal cancer (CRC).

Patients and methods

Expression profiles of mRNAs, lncRNAs, and miRNAs, and clinical information for CRC patients were obtained from The Cancer Genome Atlas. The differentially expressed mRNAs, lncRNAs, and miRNAs (referred to as “DEmRNAs”, “DElncRNAs”, and “DEmiRNAs”, respectively) were screened out between 539 CRC samples and 11 normal samples. The interactions between DElncRNAs and DEmiRNAs were predicted by miRcode. The DEmRNAs targeted by the DEmiRNAs were retrieved according to TargetScan, miRTar-Base, and miRDB. The lncRNA–miRNA–mRNA ceRNA network was constructed based on the DEmiRNA–DElncRNA and DEmiRNA–DEmRNA interactions. Functional enrichment analysis revealed the biological processes and pathways of DEmRNAs involved in the development of CRC. Key lncRNAs were further analyzed for their associations with overall survival and clinical features of CRC patients.

Results

A total of 1,767 DEmRNAs, 608 DElncRNAs, and 283 DEmiRNAs were identified as CRC-specific RNAs. Three hundred eighty-two DEmiRNA–DElncRNA interactions and 68 DEmiRNA–DEmRNA interactions were recognized according to the relevant databases. The lncRNA–miRNA–mRNA ceRNA network was constructed using 25 DEmiRNAs, 52 DEmRNAs, and 64 DElncRNAs. Two DElncRNAs, five DEmiRNAs, and six DEmRNAs were demonstrated to be related to the prognosis of CRC patients. Four DElncRNAs were found to be associated with clinical features. Twenty-eight Gene Ontology terms and 10 Kyoto Encyclopedia of Genes and Genomes pathways were found to be significantly enriched by the DEmRNAs in the ceRNA network.

Conclusion

Our results showed cancer-specific mRNA, lncRNA, and miRNA expression patterns and enabled us to construct an lncRNA-associated ceRNA network that provided new insights into the molecular mechanisms of CRC. Key RNA transcripts related to the overall survival and clinical features were also found with promising potential as biomarkers for diagnosis, survival prediction, and classification of CRC.

Novel long noncoding RNA GACAT3 promotes colorectal cancer cell proliferation, invasion, and migration through miR-149

Aim

To explore the expression and clinical significance of long noncoding RNA (lncRNA) gastric cancer-associated transcript 3 (GACAT3) in human colorectal cancer (CRC).

Methods

Expression of GACAT3 in CRC tissues and cell lines was measured using quantitative real-time PCR. CCK-8 and colony formation assays were used to assess the effect of GACAT3 on CRC cell line proliferation. Transwell invasion and migration assays were performed to detect the effect of GACAT3 on CRC cell line invasion and migration. Bioinformatics prediction, luciferase reporter assay, and pull-down assay were used to determine if miR-149 was a target of GACAT3. In addition, we also conducted colony formation assays and invasion assays to verify that GACAT3 promotes tumor progression through miR-149. Finally, in vivo tumorigenesis studies were used to demonstrate subcutaneous tumor growth.

Results

In the present study, we found that GACAT3 was highly expressed in CRC tissues and cell lines. Si-GACAT3 significantly decreased cell proliferation, motility, and invasiveness both in vitro and in vivo. We confirmed that downregulated GACAT3 significantly increased the expression of miR-149, and miR-149 binds to GACAT3 in a sequence-specific manner using luciferase reporter assays and pull-down assay. Further functional experiments indicated that GACAT3 could directly upregulate SP1 and STAT3 expressions by functioning as a competing endogenous RNA for miR-149, and consequentially, promoting CRC cell proliferation and invasion in vitro.

Conclusion

This study demonstrated that GACAT3 promotes tumor progression through competitive binding to miR-149 and suggests a promising new strategy for anti-CRC therapy.

Aberrant Expression of the Long Non-coding RNA GHRLOS and Its Prognostic Significance in Patients with Colorectal Cancer

Long non-coding RNAs (lncRNAs), which have emerged as important regulatory RNA molecules that have been implicated in carcinogenesis and cancer progression, may also serve as novel potential biomarkers for cancer diagnosis and prognosis. Our previous analysis has identified the lncRNA GHRLOS, the ghrelin antisense strand non-coding RNA gene, as one of the hub genes in the co-expression network of differentially expressed lncRNAs/mRNAs in colorectal cancer (CRC). Here, we further evaluate the expression of GHRLOS in CRC and explore its clinical significance. The expression of GHRLOS in 366 pairs of CRC and adjacent non-cancerous tissues was detected by quantitative RT-PCR assays. The results showed that the expression level of GHRLOS was significantly lower in CRC tissues than in matched non-cancerous tissues (P < 0.001). Decreased GHRLOS expression was observed in 54.4% (199/366) of cases, and was significantly correlated with the occurrence of lymph node metastasis (P = 0.033) and distant metastasis (P = 0.005). A Kaplan-Meier analysis demonstrated that decreased GHRLOS expression contributed to poor disease-free survival (log-rank test, P < 0.001) and overall survival (log-rank test, P < 0.001). Moreover, a multivariate Cox regression analysis revealed the decreased expression of GHRLOS as an independent prognostic marker of poor outcomes [disease-free survival: hazard ratio (HR) = 2.02, 95% confidence interval (CI) = 1.42-3.88; overall survival: HR = 1.96, 95% CI = 1.34-2.86] in CRC patients. In conclusion, our data suggest that the lncRNA GHRLOS might serve as a candidate biomarker of tumor metastasis and a prognostic indicator in CRC.