CircEVI5 acts as a miR-4793-3p sponge to suppress the proliferation of gastric cancer.
Ontology highlight
ABSTRACT:
SUBMITTER: Yan M
PROVIDER: S-EPMC8342614 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Prostate cancer (PCa) refers to one of the most common tumors in male's genitourinary system. Emerging research has confirmed that circRNAs play an important role in the occurrence and development of tumors. However, the correlation between circular RNA circITGA7 and PCa still remains unclear. Here, the role of circITGA7 in PCa was explored and the underlying mechanism was investigated as well. The circRNA expression profiles in PCa and the paracancerous tissues were established by high-throughput sequencing. The expression levels of circITGA7 in PCa tissues and cells were detected by qRT-PCR. Cell Counting Kit-8, colony formation, EdU, and flow cytometry assays were used to detect the effects of circITGA7 on PCa cell proliferation. To further explore the underlying mechanisms, bioinformatics analysis on downstream target genes was carried out. RNA immunoprecipitation and dual-luciferase reporter assays were used to verify the direct relationship between miR-370-3p and circITGA7 or P21CIP1. The present results demonstrated that circITGA7 was downregulated in PCa tissues and cells. Gain- or loss-of-function assays showed that circITGA7 inhibited the proliferation of PCa cells in vivo and in vitro. Mechanically, circITGA7 served as a sponge for miR-370-3p, and miR-370-3p could target P21CIP1 in PCa cells. The inhibition of cell proliferation induced by circITGA7 could be reversed by transfecting miR-370-3p mimic. Collectively, our data indicated that circITGA7 played an important role in inhibiting tumor proliferation in PCa and might be a potential therapeutic target.
| S-EPMC8741341 | biostudies-literature
Project description:BACKGROUND:As a novel type of noncoding RNAs, covalently closed circular RNAs (circRNAs) are ubiquitously expressed in eukaryotes. Emerging studies have related dysregulation of circRNAs to tumorigenesis. However, the biogenesis, regulation, function and mechanism of circRNAs in gastric cancer (GC) remain largely unclear. METHODS:The expression profile of circRNAs in 6 pairs of GC tissues and adjacent non-tumor tissues was analyzed by RNA-sequencing. Quantitative real-time PCR was used to determine the expression level of circCCDC9 in GC tissues and cell lines. Then, functional experiments in vitro and in vivo were employed to explore the effects of circCCDC9 on tumor growth and metastasis in GC. Mechanistically, dual luciferase reporter, fluorescence in situ hybridization (FISH), RNA immunoprecipitation (RIP) and RNA pull-down assays were performed to confirm that circCCDC9 directly sponged miR-6792-3p and alleviated suppression on target CAV1 expression. RESULTS:Evidently down-regulated expression of circCCDC9 was observed in both GC tissues and cell lines. Expression of circCCDC9 was negatively correlated with tumor size, lymph node invasion, advanced clinical stage and overall survival in GC patients. Functionally, overexpression of circCCDC9 significantly inhibited the proliferation, migration and invasion of GC cell lines in vitro and tumor growth and metastasis in vivo, whereas miR-6792-3p mimics counteracted these effects. Mechanistic analysis demonstrated that circCCDC9 acted as a "ceRNA" of miR-6792-3p to relieve the repressive effect of miR-6792-3p on its target CAV1, then suppressed the tumorigenesis of GC. CONCLUSIONS:CircCCDC9 functions as a tumor suppressor in inhibiting the progression of GC through miR-6792-3p/CAV1 axis, which has provided an exploitable biomarker and therapeutic target for patients with GC.
| S-EPMC7210689 | biostudies-literature
Project description:BACKGROUND:Circular RNAs (circRNAs) have recently emerged as a new family of noncoding RNAs that are involved in the causation and progression of various cancers. However, the roles of circRNAs in the tumorigenesis of gastric cancer (GC) are still largely unknown. METHODS:The expression profiles of circRNAs in GC were identified in open GEO database and were evaluated at the mRNA level in clinical GC samples compared with paired non-tumorous tissues. Kaplan-Meier survival curve was used to analyze the correlation of circRNA and patients' prognosis. Subsequently, the circular structures of candidate circRNAs were validated by Sanger sequencing, divergent primer PCR, and RNase R treatments. Gain- and loss-of-function analyses were performed to evaluate the functional significance of it in GC initiation and progression. Dual-luciferase reporter and RNA pull-down assays were used to identify the microRNA (miRNA) sponge mechanism of circRNAs. RESULTS:The expression of circRHOBTB3 was lower in GC tissues and cell lines. Downregulation of circRHOBTB3 was significantly correlated with poor differentiation and unfavorable prognosis in patients with GC. Overexpression of circRHOBTB3 in GC cells led to decreased proliferation and induced G1/S arrest in vitro, accompanied with inhibited xenograft tumor growth in vivo, while the opposite effects were achieved in circRHOBTB3-silenced cells. Furthermore, we demonstrated that circRHOBTB3 acts as a sponge for miR-654-3p and verified that p21 is a novel target of miR-654-3p. CONCLUSION:Taken together, this study revealed that circRHOBTB3 might function as competing endogenous RNA (ceRNA) for miR-654-3p, which could contribute to growth inhibition of GC through activating p21 signaling pathway. Our data suggested that circRHOBTB3 would serve as a novel promising diagnosis marker and therapeutic target for GC.
| S-EPMC6956561 | biostudies-literature
Project description:BackgroundAs a novel class of non-coding RNAs, circular RNAs (circRNAs) are key regulators of the development and progression of different cancers. However, little is known about the function and biological mechanism of circLMTK2, also named hsa_circ_0001725, in gastric cancer (GC) tumourigenesis.MethodscircLMTK2 was identified in ten paired cancer specimens and adjacent normal tissues by RNA sequencing and genome-wide bioinformatic analysis and verified by quantitative real-time PCR (qRT-PCR). Knockdown or exogenous expression of circLMTK2 combined with in vitro and in vivo assays were performed to prove the functional significance of circLMTK2. The molecular mechanism of circLMTK2 was demonstrated by searching the CircNet database and confirmed by RNA in vivo precipitation assays, western blotting, luciferase assays and rescue experiments.ResultscircLMTK2 was frequently upregulated in GC tissues, and high circLMTK2 expression was associated with poor prognosis, lymph node metastasis and poor TNM stage in GC patients. Functionally, circLMTK2 overexpression promoted GC cell proliferation and tumourigenicity in vitro and in vivo. Furthermore, ectopic circLMTK2 expression enhanced GC cell migration and invasion in vitro and tumour metastasis in vivo. In addition, we demonstrated that circLMTK2 could sponge miR-150-5p, thus indirectly regulating the c-Myc expression and contributing to GC tumourigenesis.ConclusionOur findings demonstrate that circLMTK2 functions as a tumour promoter in GC through the miR-150-5p/c-Myc axis and could thus be a prognostic predictor and therapeutic target for GC.
| S-EPMC6854648 | biostudies-literature
Project description:MicroRNA (miRNA) sponges containing miRNA complementary binding sites constitute a potentially useful strategy for miRNA-inhibition therapeutics in cancer patients. Recently, naturally occurring circular RNAs (circRNAs) have been revealed to function as efficient microRNA sponges. We hypothesized that synthetic circRNA sponges targeting oncomiRs could be constructed and used to achieve potentially therapeutic microRNA loss of function. In this study, linear RNA molecules containing five miR-21 binding sites were transcribed in vitro. After dephosphorylation by calf intestinal phosphatase and phosphorylation by T4 polynucleotide kinase, circRNA sponges were circularized using 5’-3’ end ligation by T4 RNA ligase 1. Synthetic circular sponge stability was assayed in the presence of RNase R or fetal bovine serum. Luciferase reporter and cell proliferation assays were performed to assess competitive inhibition of miR-21 activity by circRNA sponges in NCI-N87 gastric cancer cells. Tandem Mass Tag (TMT) labeling proteomics analysis and Western blotting were performed to delineate effects of circRNA sponges on miR-21 downstream targeted proteins. Our experiments revealed that artificial circRNA sponges can be synthesized using enzymatic ligation. These synthetic circRNA sponges are more resistant than their linear RNA counterparts to nuclease degradation in vitro. They effectively suppress the activity of miR-21 on its downstream protein targets, including the important cancer protein DAXX. Finally, they also inhibit gastric cancer cell proliferation. Our results suggest that synthetic circRNA sponges represent a rapid, effective, convenient strategy to achieve loss of miRNA function in vitro, with potential future therapeutic application in vivo.
2018-10-22 | PXD008584 | Pride
Project description:MicroRNA (miR) sponges containing miR binding sequences constitute a potentially powerful molecular therapeutic strategy. Recently, naturally occurring circular RNAs (circRNAs) were shown to function as efficient miR sponges in cancer cells. We hypothesized that synthetic circRNA sponges could achieve therapeutic loss-of-function targeted against specific miRs. Linear RNA molecules containing miR-21 binding sites were transcribed in vitro; after dephosphorylation and phosphorylation, circularization was achieved using 5'-3' end-ligation by T4 RNA ligase 1. circRNA stability was assessed using RNase R and fetal bovine serum. Competitive inhibition of miR-21 activity by a synthetic circRNA sponge was assessed using luciferase reporter, cell proliferation, and cell apoptosis assays in three gastric cancer cell lines. circRNA effects on downstream proteins were also delineated by Tandem Mass Tag (TMT) labeling (data available via ProteomeXchange identifier PRIDE: PXD008584), followed by western blotting. We conclude that artificial circRNA sponges resistant to nuclease digestion can be synthesized using simple enzymatic ligation steps. These sponges inhibit cancer cell proliferation and suppress the activity of miR-21 on downstream protein targets, including the cancer protein DAXX. In summary, synthetic circRNA sponges represent a simple, effective, convenient strategy for achieving targeted loss of miR function in vitro, with potential future therapeutic application in human patients.
| S-EPMC6197335 | biostudies-literature
Project description:BackgroundMany studies have confirmed that circular (circRNA) is involved in the development of gastric cancer (GC). However, the role of circFLNA in the progression of GC remains unclear.MethodsQuantitative real-time PCR (qRT-PCR) was used to measure the relative expression of circFLNA, microRNA (miR)-646 and 6-phosphofructo-2-kinase/fructose-2, 6-biphosphatase 2 (PFKFB2). Cell counting kit 8 (CCK8) assay, transwell assay and flow cytometry were performed to determine the proliferation, migration, invasion and apoptosis of cells, respectively. GC tumor xenograft models were built to confirm the function of circFLNA silencing on GC tumor growth in vivo. Furthermore, the lactate production, glucose consumption, ATP level and glucose uptake were detected to assess the glycolysis of cells. Then, the interaction between miR-646 and circFLNA or PFKFB2 was confirmed using dual-luciferase reporter assay. RNA immunoprecipitation (RIP) assay was used to verify the interaction between miR-646 and circFLNA further. In addition, Western blot (WB) analysis was employed to detect the relative protein expression of PFKFB2.ResultsOur results found that circFLNA was upregulated in GC tissues and cells. Silencing of circFLNA could suppress the proliferation, migration, invasion, glycolysis, and enhance the apoptosis of GC cells. Also, circFLNA knockdown reduced GC tumor volume and weight in vivo. Further experiments revealed that circFLNA could sponge miR-646, and miR-646 could target PFKFB2. The rescue experiments indicated that miR-646 inhibitor could reverse the suppressive effect of circFLNA silencing on GC progression, and PFKFB2 overexpression also could invert the inhibition effect of miR-646 on GC progression.ConclusionOur data concluded that circFLNA played a pro-cancer role in GC, which suggested that circFLNA might be a potential biomarker for GC treatment.
| S-EPMC7490063 | biostudies-literature
Project description:Circular RNAs (circRNAs) are a new class of RNA involved in multiple human malignancies. However, limited information exists regarding the involvement of circRNAs in gastric carcinoma (GC). Therefore, we sought to identify novel circRNAs, their functions and mechanisms in gastric carcinogenesis. We analyzed next-generation RNA sequencing data from GC tissues and cell lines, identifying 75,201 candidate circRNAs. Among these, we focused on one novel circRNA, circNF1 , which was upregulated in GC tissues and cell lines. Loss- and gain-of-function studies demonstrated that circNF1 significantly promotes cell proliferation. Furthermore, luciferase reporter assays showed that circNF1 binds to miR-16, thereby derepressing its downstream target mRNAs, MAP7 and AKT3. Targeted silencing or overexpression of circNF1 had no effect on levels of its linear RNA counterpart, NF1. Taken together, these results suggest that circNF1 acts as a novel oncogenic circRNA in GC by functioning as a miR-16 sponge.
| S-EPMC6545167 | biostudies-literature
Project description:The aim of the present study was to identify the differentially expressed microRNAs (miRs) in cervical carcinoma (CC) tissues and cells and to explore the function of miR‑302c‑3p and miR‑520a‑3p in the proliferation of CC cells. Potential dysregulated miRNAs in CC tissues and tumour‑adjacent tissues were detected. Reverse transcription‑quantitative PCR (RT‑qPCR) was performed to determine the expression of miR‑302c‑3p, miR‑520a‑3p and CXCL8 in CC tissues and cell lines. The target genes of the miRNAs were predicted using miRTarBase and verified by luciferase reporter assays. RT‑qPCR and western blotting were performed to measure the expression of C‑X‑C motif ligand (CXCL)8 after transfection. The effect on proliferation was verified by Cell Counting Kit assay and ethynyl‑2‑deoxyuridine staining. Flow cytometry was utilised to assess the effect on apoptosis. In the present study, miR‑302c‑3p and miR‑520a‑3p were markedly downregulated in CC cell lines compared to the normal cervical cell line H8. Functionally, overexpression of miR‑302c‑3p and/or miR‑520a‑3p inhibited proliferation and promoted the apoptosis of CC cell lines in vitro, while the knockdown of miR‑302c‑3p and/or miR‑520a‑3p had the opposite effect. Furthermore, miR‑302c‑3p and miR‑520a‑3p could both bind to CXCL8. Inhibition of CXCL8 in combination with miR‑302c‑3p and/or miR‑520a‑3p overexpression exerted proliferation‑suppressive and apoptosis‑stimulating effects on CC cells, whereas restoring CXCL8 attenuated the miR‑302c‑3p‑ and miR‑520a‑3p‑induced anti‑proliferative and pro‑apoptotic effects. miR‑302c‑3p and miR‑520a‑3p suppress the proliferation of CC cells by downregulating the expression of CXCL8, which may provide a novel target for the treatment of CC.
| S-EPMC7974325 | biostudies-literature
Project description:BackgroundCircular RNAs (circRNAs) are a novel class of noncoding RNAs that regulate gene expression at the transcriptional or posttranscriptional level. According to recent studies, circRNAs are involved in the pathogenesis of cancer, but the roles of circRNAs in lung adenocarcinoma are largely unknown.MethodsIn this study, we identified a novel upregulated circRNA, hsa_circ_0000326, in human lung adenocarcinoma tissues using microarray analysis and qRT-PCR. We then explored the biological role of hsa_circ_0000326 using gain- and loss-of-function assays in adenocarcinoma cells. Bioinformatics databases were used to screen for potential target miRNAs and the luciferase reporter assays and RNA-FISH further validated the interaction. Downstream protein was detected by western blot. Finally, we established xenografts in nude mice to assess the function of hsa_circ_0000326 in vivo.ResultsWe found that high expression of hsa_circ_0000326 was correlated with tumor size, regional lymph node status and differentiation in human lung adenocarcinoma. Additionally, we conducted gain- and loss-of-function assays and found that hsa_circ_0000326 acted as a positive regulator of cell proliferation and migration and a negative regulator of apoptosis. Mechanistic studies showed that hsa_circ_0000326 acted as a miR-338-3p sponge and altered the function of miR-338-3p, which in turn upregulated the expression of the downstream target RAB14 and affected the proliferation, migration and apoptosis of lung adenocarcinoma cells.ConclusionsCollectively, our study results reveal crucial roles for hsa_circ_0000326 in the proliferation, migration and apoptosis of lung adenocarcinoma cells and suggest that hsa_circ_0000326 may represent a potential therapeutic target in patients with lung adenocarcinoma.
| S-EPMC7132982 | biostudies-literature