CCAT1: an oncogenic long noncoding RNA in human cancers

Long Noncoding RNA GAPLINC Promotes Cells Migration and Invasion in Colorectal Cancer Cell by Regulating miR-34a/c-MET Signal Pathway

BACKGROUND

Gastric adenocarcinoma predictive long intergenic noncoding RNA (GAPLINC) has been detected in colorectal cancer (CRC) cells and reportedly performs many functions related to tumor proliferation and metastasis. Aim The present study aimed to comprehensively explore the biological functions of GAPLINC and their underlying mechanism in CRC cell.

METHODS

The human cancer LncRNA PCR array was used to detect the differentially expressed long noncoding RNAs in human CRC samples. Real-time PCR, dual-luciferase assay, RNA pull-down assay, Transwell assay, and western blot analysis were performed to explore the molecular mechanism underlying GAPLINC functions related to migration and invasion of a human CRC cell line (HCT116).

RESULTS

Compared to the non-cancerous tissues, GAPLINC expression was obviously increased in CRC tissues. In HCT116, silencing of GAPLINC weakened cell migration and invasion, while overexpression of GAPLINC significantly promoted cell migration and invasion. Through dual-luciferase, RNA pull-down, and Transwell assays, we verified that miR-34a was the downstream molecule of GAPLINC and that miR-34a negatively regulated the migration and invasion of HCT116 cell. Furthermore, we found that GAPLINC positively regulated the miR-34a target gene c-MET in CRC tissues.

CONCLUSIONS

Our findings revealed that GAPLINC was up-regulated in CRC tissues and was involved in the migration and invasion of CRC cells by regulating miR-34a/c-MET signaling pathway.

Role of lncRNAs in the cancer development and progression and their regulation by various phytochemicals

Long non coding RNAs (lncRNAs) are involved in modulating the expression of other non-coding RNAs (ncRNA), such as microRNAs, or target proteins through the epigenetic, transcriptional, or post-transcriptional regulations. Genomic mutations in cancer reside inside regions that do not code for proteins and these regions are often transcribed into long non coding RNAs (lncRNAs). Emerging evidences have revealed an intense involvement of lncRNAs in the cancer development and progression. Recently, emerging evidences have depicted that the phytochemicals interact with lncRNAs to modulate their activities. Such findings are highly important for the identification of therapeutic strategies against diseases that are particularly associated with an aberrant lncRNA signaling. This review aims at deciphering the role of lncRNAs in the cancer development and progression, and their regulation by various phytochemicals.

Prognostic role of the long non-coding RNA, SPRY4 Intronic Transcript 1, in patients with cancer: a meta-analysis

Recent studies have emphasized the important role of long non-coding RNAs (lncRNAs) in cancer development. The present study performed a meta-analysis to investigate whether lncRNA, SPRY4 Intronic Transcript 1(SPRY4-IT1) can be served as a potential biomarker for prognosis in human cancers. The eligible studies were collected by searching multiple online databases (Pubmed, EMBASE, CNKI, Web of Science and Google Scholar) and meta-analysis was performed to explore the association between the expression levels of SPRY4-IT1 and overall survival (OS), disease-free survival (DFS) and clinicopathological parameters. A total of 1329 patients from 13 studies were included for meta-analysis. The meta-analysis results showed that high expression level of SPRY4-IT1 was significantly associated with shorter OS in cancer patients (HR = 3.20, 95% CI: 2.59-3.90, P<0.001) except in the patients with non-small cell lung cancer (NSCLC). Increased SPRY4-IT1 expression level was correlated with shorter DFS in patients with gastric cancer and ovarian cancer. SPRY4-IT1 expression level was not correlated with the clinicopathological parameters including age (P = 0.37), gender (P = 0.87), tumor size (P = 0.47) and invasion depth (P = 0.52), and increased SPRY4-IT1 expression level was significantly associated with distant metastasis (odds ratio (OR) = 1.96, 95% CI: 1.24-3.08, P = 0.004), lymph node metastasis (OR = 3.96, 95% CI: 1.48-5.54, P<0.001), advanced tumor/node/metastasis stage (OR = 3.72, 95% CI = 2.91-4.76, P<0.001) and poor tumor differentiation (OR = 1.86, 95% CI = 1.35-2.58, P<0.001) in cancer patients except in patients with NSCLC. In summary, the meta-analysis results suggested that increased expression level of SPRY4-IT1 was positively associated with unfavorable prognosis and advanced features of cancers in cancer patients but not in patients with NSCLC.

Long non-coding RNA CCAT1 promotes multiple myeloma progression by acting as a molecular sponge of miR-181a-5p to modulate HOXA1 expression

Multiple myeloma (MM) is the second most common hematological cancer all over the world. Long non-coding RNA (lncRNA) colon cancer associated transcript-1 (CCAT1) has been reported to play important roles in the development and progression of multiple human malignancies. However, little is known about its functional role and molecular mechanism in MM. The aim of this study was to investigate the clinical and biological significance of CCAT1 in MM. Our data showed that the relative expression levels of CCAT1 were significantly upregulated in MM tissues and cell lines compared with healthy donors and normal plasma cells (nPCs). High expression of CCAT1 was correlated shorter overall survival of MM patients. CCAT1 knockdown significantly inhibited cell proliferation, induced cell cycle arrest at G0/G1 phase and promoted cell apoptosis in vitro, and suppressed tumor growth in vivo. MiR-181a-5p was a direct target of CCAT1, and repression of miR-181a-5p could rescue the inhibition of CCAT1 knockdown on MM progression. In addition, CCAT1 positively regulated HOXA1 expression through sponging miR-181a-5p in MM cells.taken together, lncRNA CCAT1 exerted an oncogenic role in MM by acting as a ceRNA of miR-181a-5p. These results suggest that CCAT1 may serve as a novel diagnostic marker and therapeutic target for MM.

Long Non-Coding RNA Cancer Susceptibility Candidate 2a (CASC2a) Is a Marker of Early Recurrence After Radical Cystectomy in Patients with Urothelial Carcinoma of the Bladder

BACKGROUND The aim of this study was to investigate the expression of long non-coding RNAs (lncRNA) cancer susceptibility candidate 2a (CASC2a) in patients with urothelial carcinoma of the bladder (UCB) and its predictive value in the recurrence of UCB after radical cystectomy (RC). MATERIAL AND METHODS Tumor and paired adjacent normal tissues were obtained from 112 patients with UCB who underwent RC in our hospital from March 2010 to March 2012. The expression of CASC2a was evaluated by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and fluorescence in situ hybridization (FISH). RESULTS CASC2a was down-regulated in UCB tissues, and was highly negatively correlated with the pT, pN, tumor size, and lymphovascular invasion (LVI). The sensitivities of CASC2a for diagnosing UCB and its recurrence after RC were 89.30% and 81.55%, respectively, and the specificities were 71.43% and 58.21%, respectively. Patients with a high expression of CASC2a had a higher 5-year recurrence-free survival rate than those with low expression of CASC2a. Kaplan-Meier survival analysis demonstrated that the pT, pN, tumor grade, tumor size, concomitant carcinoma in situ (CIS), LVI, soft tissue surgical margin (STSM), and CASC2a expression were related to the recurrence in patients undergoing RC for UCB. Cox proportional hazard model analysis showed that CASC2 expression, pT4, lymph node metastasis, and CIS were independent risk factors. CONCLUSIONS CASC2a was down-regulated in patients with UCB, and was associated with the risk of recurrence among patients undergoing RC, indicating that lncRNAs could act as predictive biomarkers and potential therapeutic targets in bladder cancer, including CASC2a.

Long noncoding RNA BLACAT1 promotes cell proliferation and invasion in human cervical cancer

Cervical cancer is one of the leading causes of mortality in females worldwide. Predisposition to distant metastasis has reduced the prognosis of this malignancy, thus the identification of a novel agent for metastatic cervical cancer is required. Long noncoding RNAs (LncRNAs) have been reported to serve significant roles in human tumorigenesis. The present study aimed to investigate the effects of a newly discovered LncRNA bladder cancer associated transcript 1 (non-protein coding) (BLACAT1) on cell proliferation and metastasis in cervical cancer. A total of 100 patients with cervical cancer were included, and tumor tissues as well as the adjacent non-cancerous counterparts were collected for reverse transcription-quantitative polymerase chain reaction analysis. It was demonstrated that BLACAT1 was highly expressed in human cervical cancer tissues and cell lines. The knockdown of BLACAT1 with specific short hairpin RNA reduced colony formation rates in ME180 and C33A cells. Cell cycle and cell proliferation assays revealed that depletion of BLACAT1 in ME180, and C33A cells arrested the cell cycle at the G0/G1 phase and inhibited cell proliferation. Transwell assays demonstrated that the knockdown of BLACAT1 inhibited cell migration and invasion in ME180, and C33A cells. Moreover, wound-healing assays supported the aformentioned observations. Western blot analysis showed that the knockdown of BLACAT1 in ME180 and C33A cells decreased the protein levels of cyclin B1, cell division cycle 25C, and N-cadherin, while increasing the protein level of E-cadherin. These findings indicated the oncogenic potential of BLACAT1 in cervical cancer, which may provide novel insights for the clinical diagnosis and treatment of cervical cancer.

Long noncoding RNA Lnc‑EGFR promotes cell proliferation and inhibits cell apoptosis via regulating the expression of EGFR in human tongue cancer

Tongue cancer remains a difficult disease to overcome. Long noncoding RNAs (LncRNAs) have been shown to serve significant roles in the diagnosis and treatment of tongue cancer. Herein, the present study aimed to investigate the role of a newly‑discovered Lnc, Lnc‑EGFR in tongue cancer. The results showed that the transcript level of Lnc‑EGFR was upregulated in patients with tongue cancer and in cultured tongue cancer cell lines. Consistently, expression of EGFR was also elevated selectively in cancerous tissues and malignant cell lines. Knockdown of Lnc‑EGFR inhibited the clonogenic ability and cell viability of human tongue cancer cell lines UM1 and CAL‑27, as evidenced by colony formation assays, and cell proliferation assays. Furthermore, depletion of Lnc‑EGFR in UM1 and CAL‑27 cells increased cell apoptosis by upregulating the activities of caspase‑3, and caspase‑9, but not caspase‑8. Lnc‑EGFR knockdown‑mediated inhibition of clonogenic ability and cell viability was rescued by overexpression of EGFR by adding EGFR recombinant protein into both cell lines. Likewise, Lnc‑EGFR knockdown‑induced cell apoptosis was reversed by co‑treatment with recombinant EGFR protein in UM1 and CAL‑27 cells. All of these results suggested the oncogenic potential of Lnc‑EGFR, which was achieved by positive regulation of EGFR in human tongue cancer.

LncRNA-CCAT1 Promotes Migration, Invasion, and EMT in Intrahepatic Cholangiocarcinoma Through Suppressing miR-152

BACKGROUND

Increasing evidence has suggested that lncRNA CCAT1 is upregulated and functions as a potential tumor promoter in many cancers. However, the potential biological roles and regulatory mechanisms of CCAT1 in intrahepatic cholangiocarcinoma (ICC) remain unclear.

METHODS

We used real-time PCR to measure CCAT1 expression in ICC tissues and the adjacent normal tissues. The statistical analyses were applied to evaluate the prognostic value and associations of CCAT1 expression with clinical parameters. The CCAT1 was silenced with siRNA in ICC cells. The migration and invasion of ICC cells were detected with Transwell assay. The expressions of epithelial-mesenchymal transition (EMT)-related proteins were evaluated to discover whether the process of EMT was involved.

RESULTS

We found that CCAT1 expression was elevated in ICC tissues compared to the adjacent normal tissues. We also found that high CCAT1 expression is closely correlated with tumor progression in ICC patients. Furthermore, our results show that knockdown of CCAT1 significantly suppressed the migration and invasion of ICC cells. Additionally, CCAT1 silencing remarkably reverses the EMT phenotype of ICC cells. Moreover, bioinformatics analysis and luciferase reporter assay revealed that CCAT1 directly bound to the miR-152, which has been reported to serve as a tumor suppressor in variety cancers. Further investigation demonstrated that CCAT1 led to the metastasis and EMT activation of ICC cells through inhibiting miR-152.

CONCLUSIONS

Our results suggested that CCAT1 functions as an oncogenic lncRNA in ICC, which could serve as a potential diagnostic and therapeutic target for ICC patients.

Long non-coding RNAs: a rising biotarget in colorectal cancer

Colorectal cancer (CRC) is a common gastrointestinal cancer, with a high incidence and high mortality. Long non-coding RNAs (lncRNAs) are involved in the development, invasion and metastasis, early diagnosis, prognosis, the chemoresistance and radioresistance of CRC through interference with mRNA activity, directly combining with proteins to regulate their activity or alter their localization, influencing downstream gene expression by inhibiting RNA polymerase and regulating gene expression as competing endogenous RNAs. Recent progress in next generation sequencing and transcriptome analysis has revealed that tissue and cancer-type specific lncRNAs could be useful prognostic markers. Here, the CRC-associated lncRNAs from recent studies until October 2016 are reviewed and multiple studies that have confirmed CRC-associated lncRNAs are summarized. This review may be helpful in understanding the overall relationships between the lncRNAs involved in CRC.

LncRNA BCAR4 promotes colon cancer progression via activating Wnt/β-catenin signaling

BCAR4 (Breast Cancer Anti-Estrogen Resistance 4) is a long noncoding RNA that was identified as an oncogene in breast cancer. In our research, we found that the expression level of BCAR4 was upregulated in colon cancer tissues compared to paired normal tissues. What's more, higher BCAR4 expression was correlated with lower survival rate in patients with colon cancer. Mechanistically, we showed that BCAR4 activated Wnt/β-catenin signaling in colon cancer by protecting β-catenin from degradation. We also showed that BCAR4 overexpression promoted cell proliferation and migration in colon cancer. However, silencing BCAR4 inhibited cell growth and promoted apoptosis. Besides, BCAR4 knockdown decreased tumor growth in vivo. These findings indicate that BCAR4 facilitated colon cancer progression by enhancing cell proliferation and inhibiting apoptosis via BCAR4/β-catenin axis. BCAR4 may be a useful new target for treatment of patients with colon cancer.

The clinical value of lncRNA NEAT1 in digestive system malignancies: A comprehensive investigation based on 57 microarray and RNA-seq datasets

This comprehensive investigation was performed to evaluate the expression level and potential clinical value of NEAT1 in digestive system malignancies. A total of 57 lncRNA datasets of microarray or RNA-seq and 5 publications were included. The pooled standard mean deviation (SMD) indicated that NEAT1 was down-regulated in esophageal carcinoma (ESCA, SMD = -0.35, 95% CI: -0.5~-0.20, P < 0.0001) and hepatocellular carcinoma (HCC, SMD = -0.47, 95% CI: -0.60~-0.34, P < 0.0001), while in pancreatic cancer (PC), NEAT1 was up-regulated (SMD = 0.45, 95% CI: 0.2~0.71, P = 0.001). However, NEAT1 expression in gastric cancer (GC), colorectal cancer (CRC), biliary tract cancer (BTC) and gallbladder carcinoma (GBC) showed no significant difference between cancer and control groups. The pooled area under the curve values for ESCA, GC, CRC, PC and HCC were 0.60, 0.89, 0.81, 0.77 and 0.69, respectively. Furthermore, our result demonstrated that a high expression of NEAT1 predicted an unfavorable prognosis in patients with digestive system malignancies (HR: 1.50, 95% CI: 1.28-1.76, P < 0.0001). Our study suggests that NEAT1 may play different roles in the initiation and progression of digestive system cancers and could be a potential diagnostic and prognostic biomarker in patients with digestive system carcinomas. Further and stricter studies with a larger number of cases are necessary to strengthen our conclusions.

LncRNA ZFAS1 promotes cell migration and invasion of fibroblast-like synoviocytes by suppression of miR-27a in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic and chronic inflammatory disease. Synoviocyte migration and invasion were found to be essential to the pathology of RA. Upregulation of long noncoding RNA ZFAS1 has been observed in cancers and promotes cell migration and invasion. To date, the functions and mechanisms of ZFAS1 in RA have not been revealed. In this study, we analyzed expression pattern of ZFAS1 in RA patients and found that ZFAS1 expression was increased in synovial tissue and fibroblast-like synoviocytes (FLS) from RA patients (RA-FLS) compared with that in healthy donors. Functional assays showed that silence of ZFAS1 suppressed RA-FLS migration and invasion, while overexpression of ZFAS1 showed the opposite effect. Further investigation demonstrated that ZFAS1 directly interacted with miR-27a and decreased miR-27a expression. ZFAS1 promotes RA-FLS migration and invasion in an miR-27a-dependent manner. Taken together, the present study provides the first evidence that ZFAS1 promotes cell migration and invasion through miR-27a in RA-FLS, suggesting that ZFAS1 may be an effective therapeutic target for RA patients.

Long Noncoding RNA and Cancer: A New Paradigm

In addition to mutations or aberrant expression in the protein-coding genes, mutations and misregulation of noncoding RNAs, in particular long noncoding RNAs (lncRNA), appear to play major roles in cancer. Genome-wide association studies of tumor samples have identified a large number of lncRNAs associated with various types of cancer. Alterations in lncRNA expression and their mutations promote tumorigenesis and metastasis. LncRNAs may exhibit tumor-suppressive and -promoting (oncogenic) functions. Because of their genome-wide expression patterns in a variety of tissues and their tissue-specific expression characteristics, lncRNAs hold strong promise as novel biomarkers and therapeutic targets for cancer. In this article, we have reviewed the emerging functions and association of lncRNAs in different types of cancer and discussed their potential implications in cancer diagnosis and therapy. Cancer Res; 77(15); 3965-81. ©2017 AACR.

Prognostic value of long non-coding RNA CCAT1 expression in patients with cancer: A meta-analysis

Background

LncRNA CCAT1 is significantly overexpressed in various types of cancers, suggesting that it might be associated with prognosis and clinicopathological features in patients with cancer.

Methods

A comprehensive search was performed in Pubmed, Web of Science, OVID and CNKI databases. We also retrieved articles from other sources, such as retrieving from the reference lists of relevant articles. Eligible studies were included based on defined exclusion and inclusion criteria to perform a meta-analysis. STATA 14.0 was used to estimate pooled hazard ratios (HRs) with 95% confidence interval (95% CI), the heterogeneity among studies and publication bias to judge the prognostic value.

Results

A total of 1587 patients from 11 eligible studies were included in the meta-analysis. The results showed that high expression level of CCAT1 was significantly associated with shorter overall survival in cancer patients (HR 2.335, 95% CI:1.551–3.517); in the subgroup analysis, region (China or UK), sample size (more or less than 100), type of cancer (digestive or non-digestive disease) and paper quality (score more or less than 7) did not alter the association between CCAT1 expression and cancer prognosis but preoperative treatment did. And CCAT1 expression was an independent prognostic marker for overall survival in patients with cancer (pooled HR 2.195, 95%CI:1.316–3.664) using Cox multivariate analyses. The clinicopathological parameters analysis further showed that increased expression level of CCAT1 was correlated with tumor size, lymph node metastasis, TNM stage, distant metastasis, microvascular invasion and capsular formation in relevant cancers.

Conclusions

The meta-analysis results from present study suggested that increased expression level of CCAT1 was associated with poor prognosis and can serve as an independent biomarker. And the expression level of CCAT1 was associated with clinicopathological features in relevant cancers.

Long non-coding RNA CCAT1/miR-148a axis promotes osteosarcoma proliferation and migration through regulating PIK3IP1

Osteosarcoma is the most frequent type of malignant primary bone tumor. Although many efforts have been made, the survival rate of osteosarcoma still remains unsatisfied. Long non-coding RNAs (lncRNAs) have been demonstrated to be associated with many diseases including tumors, and involved in the regulation of a wide array of pathophysiological processes. Colon-cancer-associated transcript-1 (CCAT1) was first identified in colon cancer and has subsequently been reported to perform many functions in tumor progression. The present study aimed to comprehensively explore the biological functions of CCAT1 and its underlying mechanism in osteosarcoma cells. Our findings revealed that CCAT1 was upregulated in osteosarcoma tissues and cells, and was involved in the proliferation and migration of osteosarcoma via regulating miR-148a/phosphatidyl inositol 3-kinase interacting protein 1 (PIK3IP1) signal pathway.

The lncRNA CCAT1 Upregulates Proliferation and Invasion in Melanoma Cells via Suppressing miR-33a

It is increasingly evident that various long noncoding RNAs (lncRNAs) participate in the tumorigenesis of multiple tumors, including melanoma. lncRNAs have been validated as oncogenic factors in various tumors; however, the potential regulatory mechanism of CCAT1 in melanoma is still unclear. The purpose of this study was to investigate the regulation of CCAT1 on melanoma genesis. The expression of CCAT1 in melanoma tissue and cell lines was measured using qRT-PCR. Interference oligonucleotide or mimic sequences were applied to up- or downregulate RNA expression. CCK-8 and colony formation assays were performed to detect the proliferation capability. Transwell assay was used to assess the migration and invasion capacities. Bioinformatics analysis was performed to predict the target miRNAs of CCAT1. Expression of CCAT1 was significantly upregulated in melanoma tissue and cell lines. CCAT1 knockdown observably suppressed the proliferation, migration, and invasion abilities. Bioinformatics analysis predicted that miR-33a acted as a target of CCAT1, which was confirmed by dual-luciferase reporter assay. CCAT1 knockdown reversed the tumor-promoting ability of the miR-33a inhibitor. CCAT1 acts as an oncogenic factor in the genesis of melanoma and exerts tumor-promoting roles via sponging miR-33a, providing a novel insight for competing endogenous RNA (ceRNA) in the tumorigenesis of melanoma.

LncRNA CCAT1 modulates the sensitivity of paclitaxel in nasopharynx cancers cells via miR-181a/CPEB2 axis

Recent studies reported that long non-coding RNA (lncRNA) might play critical roles in regulating chemo-resistant of multiple types of cancer. This study aimed to investigate whether long non-coding RNA CCAT1 was involved in Paclitaxel resistance in nasopharyngeal carcinoma (NPC). qRT-PCR was used for testing the expression of CCAT1, miR-181a and CPEB2 in tumor tissues and NPC cancers. NPC cells were transfected with siRNAs to suppress the mRNA level of CCAT1 in NPC cells. MTT assays and flow cytometry analysis were used to assess the sensitivity of paclitaxel in NPC cells. Luciferase reporter assays were used to examine the interaction of CCAT1 or CPEB2 to miR-181a. Our findings revealed that the upregulated CCAT1 results in significantly enhancing paclitaxel resistance in nasopharyngeal cancer cells. Bioinformatics analysis and luciferase reporter assay indicated that the upregulated CCAT1 sponges miR-181a in NPC cells. Furthermore, RNA immuno-precipitation assays showed that miR-181a could directly bind to CCAT1 mRNA in NPC cells. We restored miR-181a in NPC cells, and found restoration of miR-181a re-sensitized the NPC cells to paclitaxel in vitro. In addition, our results also showed that miR-181a was a modulator of paclitaxel sensitivity due to its regulative effect on cell apoptosis via targeting CPEB2 in NPC cells. Taken together, lncRNA CCAT1 regulates the sensitivity of paclitaxel in NPC cells via miR-181a/CPEB2 axis.

oncoNcRNA: A Web Portal for Exploring the Non-Coding RNAs with Oncogenic Potentials in Human Cancers

Non-coding RNAs (ncRNAs) have been shown to contribute to tumorigenesis and progression. However, the functions of the majority of ncRNAs remain unclear. Through integrating published large-scale somatic copy number alterations (SCNAs) data from various human cancer types, we have developed oncoNcRNA, a user-friendly web portal to explore ncRNAs with oncogenic potential in human cancers. The portal characterizes the SCNAs of over 58,000 long non-coding RNAs (lncRNAs), 34,000 piwi-interacting RNAs (piRNAs), 2700 microRNAs (miRNAs), 600 transfer RNAs (tRNAs) and 400 small nucleolar RNAs (snoRNAs) in 64 human cancer types. It enables researchers to rapidly and intuitively analyze the oncogenic potential of ncRNAs of interest. Indeed, we have discovered a large number of ncRNAs which are frequently amplified or deleted within and across tumor types. Moreover, we built a web-based tool, Correlations, to explore the relationships between gene expression and copy number from ~10,000 tumor samples in 36 cancer types identified by The Cancer Genome Atlas (TCGA). oncoNcRNA is a valuable tool for investigating the function and clinical relevance of ncRNAs in human cancers. oncoNcRNA is freely available at http://rna.sysu.edu.cn/onconcrna/.