Colon Cancer-associated Transcript Research Articles

Downregulation of lncRNA CCAT1 enhances 5-fluorouracil sensitivity in human colon cancer cells

BackgroundThe purpose of this study was to determine the aberrant expression of the long noncoding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) in 5-fluorouracil-resistant colonic neoplasm cells and to elucidate its effects on the 5-fluorouracil sensitivity of human colonic neoplasm cells. The aberrant expression of lncRNAs in normal tissues and colonic neoplasm tissues was detected by microarray assay. qRT-PCR analysis was performed to assess CCAT1 expression levels in colonic neoplasm cell lines and corresponding normal tissues. After constructing the 5-FU-resistant cell lines and validating the resistance by measuring the IC50 value, the CCAT1 expression levels in parental and artificially resistant cell lines were determined by qRT-PCR. Transfection was used to modulate the expression of CCAT1. Cell proliferation and apoptosis were then detected by CCK-8 and flow cytometry, respectively.ResultsCCAT1 in colon cancer tissues was higher than that in noncancer tissues, and the levels of CCAT1 in HCT 116, SW1417, HT-29, and KM12 cell lines were higher than those in the human normal colon epithelial NCM460 cell line. Moreover, the expression levels of CCAT1 were high in HCT 116/5-FU and HT-29/5-FU cell lines, whose apoptosis rates induced by 5-FU were lower than those in corresponding parental cells. The results of qRT-PCR and CCK-8 assay showed that enhancement of lncRNA CCAT1 expression levels in HCT 116 and HT-29 cell lines increased their IC50 of 5-FU and decreased their apoptosis rates. Meanwhile, siRNA-CCAT1 effectively inhibited the expression of CCAT1 and enhanced the 5-FU-sensitivity of HCT 116/5-FU and HT-29/5-FU, in which apoptosis rates were increased at the same time.ConclusionsDownregulation of CCAT1 effectively reversed the resistance of HCT 116/5-FU and HT-29/5-FU cells to 5-FU chemotherapeutic, opening a new avenue in colon cancer therapy.

The lncRNA CCAT2 rs6983267 G allele is associated with decreased susceptibility to recurrent miscarriage.

Genetics might play various roles in susceptibility to recurrent miscarriage, and previous studies suggest that some gene polymorphisms might be associated with abortion and breast cancer onset. Colon cancer-associated transcript 2 (CCAT2) is a novel long noncoding RNA (lncRNA) transcript that might be correlated with susceptibility to multiple cancers, including breast cancer. However, whether lncRNA CCAT2 polymorphisms are related to susceptibility to recurrent miscarriage is unclear. We genotyped two lncRNA CCAT2 polymorphisms (rs6983267 and rs3843549) in 248patients with recurrent miscarriage and 392 controls through a TaqMan real-time polymerase chain reaction assay, and the strength of each association was evaluated via 95% confidence intervals (CIs) and odds ratios (ORs). Our results showed that the rs6983267 G allele in lncRNA CCAT2 was associated with decreased susceptibility to recurrent miscarriage (TG vs. TT: adjusted OR = 0.603; 95% CI = 0.420-0.866; p = 0.0062; GG/TG vs. TT: adjusted OR = 0.620; 95% CI = 0.441-0.873; p = 0.0061). The combined analysis of the two protective polymorphisms (rs3843549 AA and rs6983267 TG/GG) revealed that individuals with two unfavorable alleles exhibited a lower risk of recurrent miscarriage than those with no or only one unfavorable allele (adjusted OR = 0.531; 95% CI = 0.382-0.739). Moreover, the decreased risk associated with the two protective alleles was most obvious in women aged less than 35 years (OR = 0.551; 95% CI = 0.378-0.8803; p = 0.0019) and in women with two to three miscarriages (adjusted OR = 0.466; 95% CI = 0.318-0.683; p < 0.0001). In conclusion, our study indicates that the rs6983267G allele might contribute to a decreased risk of recurrent miscarriage in the South Chinese population.

LncRNA CCAT1 negatively regulates miR‑181a‑5p to promote endometrial carcinoma cell proliferation and migration

Long non-coding RNAs (lncRNAs) are identified as vital modulators in a number of biological processes, including tumorigenesis. However, the role of lncRNAs in endometrial carcinoma (EC) remains unknown. In the current study, the expression patterns, biological roles and functional mechanism of the lncRNA colon cancer associated transcript 1 (CCAT1) was examined in EC. The expression level of CCAT1 was significantly upregulated in EC tissue samples compared with matched adjacent healthy tissue samples from patients with endometrial cancer. Similarly, CCAT1 was significantly upregulated in several EC cell lines (KLE, Ishiwaka and HEC-1-A), compared with the normal human endometrial stromal cell line T-HESC. Cell counting kit-8 and Transwell migration assays demonstrated that CCAT1 knockdown significantly decreased EC cell proliferation and migration. In addition, CCAT1 was confirmed as a target gene of miR-181a-5p in EC. Overexpression of miR-181a-5p significantly decreased CCAT1 expression in EC cells, whilst knockdown of CCAT1 significantly increased miR-181a-5p expression in EC cells. Furthermore, miR-181a-5p expression was significantly downregulated in EC tissue samples compared with matched adjacent healthy tissue samples from patients with endometrial cancer. Similarly, miR-181a-5p expression was significantly downregulated in several EC cell lines (KLE, Ishiwaka and HEC-1-A), compared with normal human endometrial stromal cell line T-HESC. In addition, rescue experiments demonstrated that inhibition of miR-181a-5p significantly reversed the effect of CCAT1 knockdown on EC cell proliferation and migration. The results suggest that CCAT1 promotes EC progression by acting as a molecular sponge of miR-181a-5p.

Circulating long non-coding RNA colon cancer-associated transcript 2 protected by exosome as a potential biomarker for colorectal cancer

BackgroundColon cancer-associated transcript 2 (CCAT2) plays a crucial role in several cancers. However, the clinical significance of circulating CCAT2 expression in colorectal cancer (CRC) has not previously been elucidated. In this study, we aimed to elucidate the potential role of CCAT2 and its clinical significance of circulating expression level in CRC. MethodsWe detected the expression of CCAT2 in 75 pairs of tumorous and adjacent non-tumorous tissues derived from CRC patients by quantitative real-time polymerase chain reaction. The serum levels of CCAT2 expression were detected in an independent cohort of healthy controls and CRC patients. We analyzed the relationship between CCAT2 levels in serum and clinicopathological features of CRC patients. We also compared CCAT2 levels in paired pre-operative and post-operative serum samples. Furthermore, the existence of serum CCAT2 in exosomes was investigated. ResultsThe levels of CCAT2 expression were significantly over-expressed in tumor tissues (p < 0.05) compared to adjacent non-tumorous tissues. Higher CCAT2 expression was associated with advanced CRC patients. Moreover, the serum levels of CCAT2 expression were significantly over-expressed in CRC patients (p < 0.05) compared to those in healthy subjects. In addition, the CCAT2 levels were significantly decreased in post-operative samples than those in pre-operative ones (P = 0.01). We also found that CCAT2 expression was up-regulated in CRC exosomes (P < 0.001) and no significant differences of CCAT2 levels were found between in serum and in exosomes. ConclusionsOur data indicate that circulating CCAT2 which might protected by exosomes can serve as a novel potential predictor in CRC.

Upregulated LncRNA-CCAT1 promotes hepatocellular carcinoma progression by functioning as miR-30c-2-3p sponge.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death over the world. It is well studied that long noncoding RNA colon cancer-associated transcript-1 (CCAT1) played important roles in variety of cancers promoting cell proliferation and metastasis by acting as a competing endogenous RNA (ceRNA) of microRNAs. However, whether CCAT1 could regulate HCC by serving as a ceRNA of microRNA remains to be revealed. In this study, we demonstrated that CCAT1 was highly expressed in HCC tissues and remarkably associated with metastasis. With a bioinformatics prediction and functional assay validation, we found a binding site of miR-30c-2-3p on CCAT1, which was important for CCAT1 to promote cell proliferation. Interestingly, we further revealed a novel recognition site for miR-30c-2-3p on the 3'UTR of CCNE1 by mutative method, luciferase assay, and cell viability confirmation. In general, CCAT1 regulate the expression of CCNE1 by acting as a ceRNA to sponge miR-30c-2-3p in regulating the cell proliferation of HCC. These results suggest that CCAT1 may be a new therapy target for HCC in the future. SIGNIFICANCE OF THE STUDY: Our findings may broaden the understanding of the role of CCAT1 in tumorigenesis and may provide a new therapy target for HCC.

RETRACTED: Ginsenoside Rg3 inhibits cell growth, migration and invasion in Caco-2 cells by downregulation of lncRNA CCAT1

Colorectal cancer (CRC) is a troublesome disease with high morbidity and mortality. Ginsenoside Rg3 possesses anti-cancer properties. Colon Cancer Associated Transcript 1 (CCAT1) participates in the genesis, development, invasion and metastasis of colorectal cancer. In our study, we explored the effects of Rg3 on CRC cell line Caco-2 by regulating CCAT1. CRC tissue was obtained from hospital and Caco-2 cells were purchased. Caco-2 cells were treated with Rg3 and/or transfected with pc- CCAT1 or pcDNA3.1. The group without Rg3 treatment was treated as control. Cell viability, cell apoptosis, cell migration and invasion were detected by Cell Counting Kit-8 assay, flow cytometry and Transwell chamber migration/invasion assay, respectively. The expression of CyclinD1, apoptosis related proteins (p53, Bcl-2, Bax, pro-/Cleaved-Caspase-3), migration and invasion related proteins (MMP-9 and vimentin), and phosphatidylinositol 3'-kinase (PI3K)/protein kinase B (AKT) related proteins (p/t-PI3K, p/t-AKT) were examined by western blot. The expression of CCAT1 was measured by quantitative real time RCR (qRT-PCR). Rg3 significantly decreased cell viability, migration and invasion, and promoted apoptosis. Meanwhile, the expression of Cyclin D1, matrix metalloproteinase (MMP)-9 and vimentin was downregulated. The expression of apoptosis-related proteins p53, Bax, and Cleaved-Caspase-3 were upregulated while Bcl-2 was downregulated by the treatment of Rg3 compared with control. Furthermore, CCAT1 was upregulated in CRC tissue and Rg3 negatively regulated CCAT1 expression. Transfection with pc-CCAT1 led to the opposite results as compared with transfection with pcDNA3.1 in Rg3 treated cells. In addition, Rg3 decreased the phosphorylation of PI3K and AKT. Ginsenoside Rg3 inhibits migration and invasion, and promotes apoptosis of Caco-2 cells by suppression expression of LncRNA CCAT1.

CCAT1 lncRNA Promotes Inflammatory Bowel Disease Malignancy by Destroying Intestinal Barrier via Downregulating miR-185-3p.

The long noncoding RNA (lncRNA) colon cancer-associated transcript-1 (CCAT1) has been reported to play a vital role in the development of cancer. Although the link between inflammation and cancer initiation is well established, whether CCAT1 is involved in inflammation and promotes inflammatory bowel disease (IBD) malignancy remains undetermined. We aimed to investigate the expression of CCAT1 in IBD and the effect of CCAT1 overexpression on intestinal epithelial barrier function. The relationship between CCAT1 and the inflammation-related pathway was analyzed in both colorectal cancer (CRC) and IBD patients. Gene expression was detected by real-time polymerase chain reaction and Western blot. Transepithelial electrical resistance (TEER) and FD-4 flux measurement were used to test the effect of CCAT1 and miR-185-3p on intestinal epithelial barrier function. Luciferase assay was performed to validate the target site of miR-185-3p on 3'-UTR of MLCK mRNA. Gene set enrichment analysis revealed that several inflammation-related genes were enriched in the CCAT1 high-expressed group of CRC patients. The relationship between CCAT1 and inflammation activation in IBD patients was further confirmed. CCAT1 expression positively correlated with MLCK, which acts as a protein kinase to phosphorylate myosin light chain and induces tight junction protein distribution, whereas it was negatively correlated with miR-185-3p in IBD tissues. We also determined that CCAT1 overexpression increased Caco-2 monolayer permeability and upregulated MLCK. Furthermore, CCAT1-induced MLCK overexpression and IBD disease progression were significantly attenuated by miR-185-3p. The CCAT1/miR-185-3p/MLCK signaling pathway is strongly activated to destroy barrier function and promotes the pathogenesis of IBD.

Baicalein restrains proliferation, migration, and invasion of human malignant melanoma cells by down-regulating colon cancer associated transcript-1.

Baicalein (BAI) is an acknowledged flavonoids compound, which is regarded as a useful therapeutic pharmaceutical for numerous cancers. However, its involvement in melanoma is largely unknown. This study aimed to examine the anti-melanoma function of BAI and unraveled the regulatory mechanism involved. A375 and SK-MEL-28 were treated with BAI for 24 h. Then, CCK-8 assay, flow cytometry, and transwell assay were carried out to investigate cell growth, migration, and invasion. RT-qPCR was applied to detect the expression of colon cancer associated transcript-1 (CCAT1) in melanoma tissues and cells. The functions of CCAT1 in melanoma cells were also evaluated. Western blot was utilized to appraise Wnt/β-catenin or MEK/ERK pathways. BAI restrained cell proliferation and stimulated cell apoptotic capability of melanoma by suppressing cleaved-caspase-3 and cleaved-PARP. Cell migratory and invasive abilities were restrained by BAI via inhibiting MMP-2 and vimentin. CCAT1 was over-expressed in melanoma tissues and down-regulated by BAI in melanoma cells. Overexpressed CCAT1 reversed the BAI-induced anti-growth, anti-migratory, and anti-invasive effects. Furthermore, BAI inhibited Wnt/β-catenin and MEK/ERK pathways-axis via regulating CCAT1. Our study indicated that BAI blocked Wnt/β-catenin and MEK/ERK pathways via regulating CCAT1, thereby inhibiting melanoma cell proliferation, migration, and invasion.

Non-Coding RNAs in Breast Cancer: Intracellular and Intercellular Communication.

Non-coding RNAs (ncRNAs) are regulators of intracellular and intercellular signaling in breast cancer. ncRNAs modulate intracellular signaling to control diverse cellular processes, including levels and activity of estrogen receptor α (ERα), proliferation, invasion, migration, apoptosis, and stemness. In addition, ncRNAs can be packaged into exosomes to provide intercellular communication by the transmission of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) to cells locally or systemically. This review provides an overview of the biogenesis and roles of ncRNAs: small nucleolar RNA (snRNA), circular RNAs (circRNAs), PIWI-interacting RNAs (piRNAs), miRNAs, and lncRNAs in breast cancer. Since more is known about the miRNAs and lncRNAs that are expressed in breast tumors, their established targets as oncogenic drivers and tumor suppressors will be reviewed. The focus is on miRNAs and lncRNAs identified in breast tumors, since a number of ncRNAs identified in breast cancer cells are not dysregulated in breast tumors. The identity and putative function of selected lncRNAs increased: nuclear paraspeckle assembly transcript 1 (NEAT1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), steroid receptor RNA activator 1 (SRA1), colon cancer associated transcript 2 (CCAT2), colorectal neoplasia differentially expressed (CRNDE), myocardial infarction associated transcript (MIAT), and long intergenic non-protein coding RNA, Regulator of Reprogramming (LINC-ROR); and decreased levels of maternally-expressed 3 (MEG3) in breast tumors have been observed as well. miRNAs and lncRNAs are considered targets of therapeutic intervention in breast cancer, but further work is needed to bring the promise of regulating their activities to clinical use.

Pivotal prognostic and diagnostic role of the long non‑coding RNA colon cancer‑associated transcript 1 expression in human cancer (Review).

Long non-coding RNAs (lncRNAs) have been classically defined as regulatory RNA members >200 nucleotides in length, without detectable open-reading frames to encode proteins. Previous studies have demonstrated that lncRNAs serve critical roles in multiple cancer types. Colon cancer-associated transcript 1 (CCAT1), a novel cancer-associated lncRNA, is significantly overexpressed in a number of malignancies. Functionally, as an oncogenic lncRNA, CCAT1 is involved in proliferation, migration, cell cycle progression, apoptosis, chemoresistance and other biological processes of cancer cells through complex regulation mechanisms in the cytoplasm or nucleus. In clinical applications, CCAT1 is additionally positively associated with histological differentiation, tumour node metastasis stage, vascular invasion, overall survival and recurrence-free survival, which demonstrates its important role as a diagnostic and prognostic marker in cancer. The present review summarises the current research progress of the oncogenic potential and clinical uses of CCAT1 in various human cancer types.

CX-3543 Promotes Cell Apoptosis through Downregulation of CCAT1 in Colon Cancer Cells.

Aim Colon cancer-associated transcript-1 (CCAT1), located in the vicinity of transcription factor c-Myc, was first identified in colon cancer. A small-molecule compound CX3543 (Quarfloxin) selectively targeting Myc G-quadruplexes has entered phase II clinical trials for neuroendocrine carcinomas. The aim of the study was to explore the relationship between CX3543, CCAT1, and cell apoptosis in colon cancer cells. Methods Semiquantitative PCR was used to detect the relative expression of CCAT1 in colon cancer (CC) tissues and HT29 cell lines. Real-time PCR (RT-PCR) was also used to investigate the expression of CCAT1 and c-Myc after HT29 cells being treated by CX3543 for 24 h. Cell apoptosis assay and cell proliferation assay were conducted in HT29 cells after being treated by CX3543. Results The results showed that the expression of CCAT1 was remarkably increased in CC tissues and HT29 cells compared to controls. CX3543 treatment reduced the expression of c-Myc and CCAT1 and promoted cell apoptosis and inhibited cell proliferation. After the expression of CCAT1 was inhibited by sh-CCAT1 transfection, the cell apoptosis rate was higher than that of control group. After the cells were treated by CCAT1 overexpression plasmid transfection and CX3543, the cell apoptosis rate was lower than that of control group. In vivo results showed that CX3543 inhibited the xenograft tumor growth of rats through downregulation of CCAT1. Conclusion Our study demonstrated that CX3543 could inhibit the progression of colon cancer by downregulating CCAT1 expression and might be a potential drug for the treatment of colon cancer.

Long non-coding RNA-CCAT2 promotes the occurrence of non-small cell lung cancer by regulating the Wnt/β-catenin signaling pathway.

The present study aimed to investigate the biological function of colon cancer-associated transcript 2 (CCAT2) in the occurrence and progression of non-small cell lung carcinoma (NSCLC) and its potential use in the early diagnosis and molecular-targeted therapy of NSCLC. The tumor tissues, para-carcinoma tissues and associated clinical data of 36 patients with NSCLC were collected in order to detect the expression of CCAT2 and assess the impact of factors including histopathological type, Tumor-Node-Metastasis stage and lymph node metastasis on CCAT2 expression. The lung cancer NCI-H1975 cell line was transfected with a small interfering RNA (siRNA) plasmid to determine the effect of si-CCAT2 on NSCLC proliferation, invasion and metastasis. The effect of si-CCAT2 on the expression of nuclear and cytoplasmic β-catenin protein in the lung cancer NCI-H1975 cell line was detected using western blot analysis. The expression levels of CCAT2 in the tumor tissues of patients with NSCLC were significantly higher than those in the normal para-carcinoma tissues (t=8.580, P<0.01). Subsequent to CCAT2 silencing, the proliferation and invasive abilities of NCI-H1975 cells were significantly decreased compared with control cells (P<0.05). In the si-CCAT2 group, the level of nuclear and cytoplasmic β-catenin proteins was decreased, and the activity of the Wnt signaling pathway was significantly inhibited compared with the control cells (P<0.01), and a synergistic effect was exerted with the Wnt signaling inhibitor FH535. CCAT2 may therefore promote the occurrence of NSCLC by regulating the Wnt/β-catenin signaling pathway.

Identification of long non-coding RNA CCAT1 as an oncogene in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a common type of cancer worldwide. Long non-coding RNAs (lncRNAs) have been demonstrated to be associated with the development of multiple types of human cancer. The present study aimed to identify the potential role of lncRNA colon cancer associated transcript 1 (CCAT1) in NPC. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression levels of CCAT1 in NPC tissues and cell lines. The function of CCAT1 in the proliferation, migration, invasion and apoptosis of NPC cells was detected by MTT, cell scratch, Transwell, flow cytometry and caspase-3 ELISA assays, respectively. The results indicated that the expression levels of CCAT1 were significantly upregulated in NPC tissues compared with normal nasopharyngeal epithelial tissues. CCAT1 expression was also higher in SUNE-1 and C666-1 cells compared with NP69 cells. Furthermore, the knockdown of CCAT1 was indicated to inhibit growth, migration and invasion, and induce apoptosis in NPC cells. In conclusion, the present study is, to the best of our knowledge, the first to provide new findings that support an oncogenic role of CCAT1 in NPC. Further research is required to define the potential molecular mechanism of CCAT1 in the development of NPC.

Overexpression of the long noncoding RNA CCAT1 promotes metastasis via epithelial-to-mesenchymal transition in lung adenocarcinoma.

The long noncoding RNA (lncRNA) colon cancer-associated transcript 1 (CCAT1) has been identified as an oncogene in multiple types of human malignancy, and the aberrant expression of CCAT1 has been associated with the tumorigenesis and progression of cancer. However, the underlying mechanism of how CCAT1 affects malignant behaviors in lung adenocarcinoma cells remains unknown. In the current study, the expression of CCAT1 was identified to be increased in lung adenocarcinoma tissues (n=96) by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and its expression level was associated with epidermal growth factor receptor (EGFR) expression (P=0.011), lymphatic metastasis (P=0.003) and tumor node metastasis (TNM) stage (P=0.003). In vitro, by using Transwell assays, the overexpression of CCAT1 was demonstrated to promote the migration and invasion of H358 lung adenocarcinoma cells; while downregulation of CCAT1 expression inhibited H1650 cell migration and invasion. Furthermore, western blot analysis indicated that aberrant CCAT1 expression may induce epithelial-to-mesenchymal transition (EMT) by regulating the expression levels of EMT markers (E-cadherin, N-cadherin and vimentin). In conclusion, these results indicate that CCAT1 is able to promote the metastasis of lung adenocarcinoma cells by inducing EMT.

Long non-coding RNA CCAT1 as a diagnostic and prognostic molecular marker in various cancers: a meta-analysis.

PurposeLong non-coding RNA colon cancer-associated transcript-1 (CCAT1) is newly found to be related with diagnoses and prognosis of cancer. This meta-analysis was performed to investigate the relationship between CCAT1 expression and clinical parameters, including survival condition, lymph node metastasis and tumor node metastasis grade.Materials and MethodsThe primary literatures were collected through initial search criteria from electronic databases, including PubMed, OVID Evidence-based medicine Reviews and others (up to May 12, 2017). Eligible studies were identified and selected by the inclusion and exclusion criteria. Data was extracted and computed into Hazard ratio (HR) for the assessment of overall survival, subgroup analyses were prespecified based on the digestive tract cancer or others. Analysis of different CCAT1 expression related with lymph node metastasis or tumor node metastasis grade was conducted. Risk of bias was assessed by the Newcastle-Ottawa Scale.Results9 studies were included. This meta-analysis showed that high CCAT1 expression level was related to poor overall survival, the pooled HR was 2.42 (95% confidence interval, CI: 1.86-3.16; P < 0.001; fix- effects model), similarly in the cancer type subgroups: digestive tract cancer (HR, 2.42; 95% CI, 1.79–3.29; P < 0.001; fix- effects model) and others (HR, 2.42; 95% CI, 1.42–4.13; P = 0.001; fix- effects model). The analysis showed that high CCAT1 was strongly related to positive lymph node metastasis (Odds ratio, OR: 3.24; 95% CI, 2.04-5.16; P < 0.001; fix- effects model), high tumor node metastasis stage (OR, 3.87; 95% CI, 2.53–5.92; P < 0.001; fix- effects model).ConclusionsIn conclusion, this meta-analysis revealed that CCAT1 had potential as a diagnostic and prognostic biomarker in various cancers.

LncRNA CCAT2 enhances cell proliferation via GSK3β/β-catenin signaling pathway in human osteosarcoma.

Osteosarcoma(OS) is a kind of malignant bone tumor. The aim of the manuscript is to investigate the clinical significance and the functional effects of long non-coding (lncRNA) coloncancer-associated transcript 2 (CCAT2) in osteosarcoma. Expression of CCAT2 was detected by quantitative Real-time PCR (qRT-PCR) in 50 cases of osteosarcoma tissue samples and adjacent normal bone tissues. Kaplan-Meier survival analysis and log-rank test were used to assess the association between CCAT2 expression and prognosis of OS patients. Cell Counting Kit 8 and cell colony formation assays were performed to evaluate cell proliferation. The protein expression of PCNA, p-GSK3β, GSK3β, and β-catenin were analyzed using Western blot analysis. We demonstrated that lncRNA CCAT2 expression was significantly upregulated in OS tissues compared to adjacent normal bone tissues. Higher lncRNA CCAT2 expression positively associated with larger tumor size, advanced tumor stage and poor overall survival (OS) rate of patients. In vitro, knockdown of lncRNA CCAT2 suppressed cell proliferation and colony formation ability. In contrast, overexpression of lncRNA CCAT2 showed promoting cell proliferation effects in OS. Also, we found that knockdown of lncRNA CCAT2 inhibited GSK3β/β-catenin signaling by reducing p-GSK3β and β-catenin expression, but increasing GSK3β expression. Our results showed that CCAT2 is a crucial oncogene in OS and may be a potential therapeutic target of OS.

Tudor-staphylococcal nuclease regulates the expression and biological function of alkylglycerone phosphate synthase via nuclear factor-κB and microRNA-127 in human glioma U87MG cells.

Glioma is one of the malignant tumor types detrimental to human health; therefore, it is important to find novel targets and therapeutics for this tumor. The downregulated expression of Tudor-staphylococcal nuclease (SN) and alkylglycerone phosphate synthase (AGPS) can decrease cancer malignancy, and the overexpression of them can the increase viability and migration potential of various tumor cell types; however, the role of AGPS in the proliferation and migration of glioma, and the association of Tudor-SN and AGPS in human glioma is not clear. In the present study, it was determined that AGPS silencing suppressed the proliferation and migration potential of glioma U87MG cells, and suppressed the expression of the circular RNAs circ-ubiquitin-associated protein 2, circ-zinc finger protein 292 and circ-homeodomain-interacting protein kinase 3, and the long non-coding RNAs H19 imprinted maternally expressed transcript (non-protein coding), colon cancer-associated transcript 1 (non-protein coding) and hepatocellular carcinoma upregulated long non-coding RNA. Furthermore, Tudor-SN silencing suppressed the expression of AGPS; however, nuclear factor (NF)-κB and microRNA (miR)-127 retrieval experiments partially reduced the expression of AGPS. Additionally, it was determined that Tudor-SN silencing suppressed the activity of the mechanistic target of rapamycin (mTOR) signaling pathway, and NF-κB and miR-127 retrieval experiments partially reduced the activity of mTOR. Therefore, it was considered that NF-κB and miR-127 may be the mediators of Tudor-SN-regulated AGPS via the mTOR signaling pathway. These results improve on our knowledge of the mechanisms underlying Tudor-SN and AGPS in human glioma.

Long Noncoding RNA CCAT2 Knockdown Suppresses Tumorous Progression by Sponging miR-424 in Epithelial Ovarian Cancer.

Epithelial ovarian cancer (EOC) is the one of most common gynecological malignant tumors with high mortality. A series of long noncoding RNAs (lncRNAs) have been validated to play a vital role in EOC tumorigenesis. Colon cancer-associated transcript 2 (CCAT2) has been verified as an oncogenic lncRNA in multiple tumors; however, the role of CCAT2 in EOC genesis is still unclear. The purpose of the present study was to probe the function of CCAT2 on EOC. Preliminary experiments found that CCAT2 expression was significantly upregulated in EOC tissues and cell lines compared to noncancerous tissue and cells. CCAT2 knockdown induced by interfering oligonucleotides could inhibit proliferation and promote apoptosis and induce cell cycle arrest at the G0/G1 phase. Bioinformatics analysis predicted that miR-424 targeted CCAT2, which was confirmed by luciferase reporter assay. Moreover, the miR-424 inhibitor rescued the tumorigenesis inhibition induced by CCAT2 knockdown. In summary, our findings illustrate that CCAT2 acts as competing endogenous RNA (ceRNA) or sponge via negatively targeting miR-424, providing a novel diagnostic marker and therapeutic target for EOC.

LncRNA CCAT2 promoted osteosarcoma cell proliferation and invasion.

Long non‐coding RNA (lncRNA) plays important roles in tumour progression. Accumulating studies demonstrated that lncRNA colon cancer‐associated transcript 2 (CCAT2) acted as an oncogene in many tumours. However, the role of CCAT2 in the development of osteosarcoma has not been elucidated. In our study, we indicated that CCAT2 expression was up‐regulated in osteosarcoma tissues and cell lines (SOSP‐9607, MG‐63, U2OS and SAOS‐2). In addition, osteosarcoma cases with higher CCAT2 expression had a poorer disease‐free survival and shorter the overall survival time compared to those with lower expression. Overexpression of CCAT2 promoted osteosarcoma cell proliferation, invasion and cell cycle. Furthermore, ectopic expression of CCAT2 increased the expression of mesenchymal markers N‐cadherin, vimentin and snail and reduced the expression of N‐cadherin marker E‐cadherin. CCAT2 overexpression promoted the LATS2 and c‐Myc expression in osteosarcoma cell. These data indicated that CCAT2 served as an oncogene in osteosarcoma and promoted osteosarcoma cell proliferation, cell cycle and invasion.

Upregulation of long non‑coding RNA CCAT2 indicates a poor prognosis and promotes proliferation and metastasis in intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (IHCC) is an aggressive cancer with a poor survival rate and is the second most common type of primary cancer of the hepatobiliary system. At present, the molecular mechanisms of IHCC initiation and progression remain unclear. Recent evidence has indicated that long non‑coding RNAs (lncRNAs) serve a crucial role in cancer development; however, the functional role of lncRNAs in IHCC has not been investigated in detail. In the present study, a marked overexpression of lncRNA colon cancer‑associated transcript2 (CCAT2) was observed in IHCC cell lines and clinical specimens. Statistical analysis of IHCC clinicopathological characteristics and CCAT2 expression data revealed that high CCAT2 expression levels correlated with microvascular invasion, differentiation grade, tumor (T), lymph node (N), metastasis (M) and overall TNM stages of IHCC (P<0.05). Kaplan‑Meier analysis demonstrated that CCAT2 upregulation was associated with poor overall survival and progression‑free survival in IHCC. Furthermore, high CCAT2 expression was identified as an independent risk factor of IHCC poor prognosis in both univariate and multivariate Cox regression analyses. The role of CCAT2 in promoting IHCC cell proliferation, motility and invasion was further confirmed with invitro assays. Therefore, CCAT2 may promote IHCC progression and metastasis, and may be a promising prognostic biomarker and therapeutic target in IHCC.