Knockdown Of circRNA Research Articles

CircRNA_100290 promotes GC cell proliferation and invasion via the miR-29b-3p/ITGA11 axis and is regulated by EIF4A3

BackgroundCircular RNAs (circRNAs) have been reported to be important regulators of the development and progression of various carcinomas. However, the role of circRNA_100290 in gastric cancer (GC) is still unclear. This study aimed to investigate the role of circRNA_100290 in GC invasion and metastasis and the possible underlying mechanism.MethodsThe expression of circRNA_100290 in GC cells and tissues was examined using quantitative real-time polymerase chain reaction (qRT-PCR). The role of circRNA_100290 in cell proliferation, migration, and invasion was evaluated in the AGS and HGC-27 cell lines in vitro. Bioinformatics tools, dual-luciferase reporter assays, Western blot assays and qRT-PCR were used to explore the pathways downstream of circRNA_100290. The mechanism underlying the regulation of circRNA_100290 expression was explored using RNA immunoprecipitation, qRT-PCR, and Western blot assays.ResultsThe expression of circRNA_100290 was significantly upregulated in GC cells and 102 GC tissues, and high circRNA_100290 expression in GC was closely related to Borrmann’s type, lymph node metastasis and tumour-node-metastasis stage. In vitro, knockdown of circRNA_100290 in AGS and HGC-27 cells significantly inhibited cell proliferation, migration, and invasion. Mechanistically, a dual-luciferase reporter assay confirmed the direct interaction between circRNA_100290 and miR-29b-3p, which targets ITGA11, an oncogene that is closely related to epithelial–mesenchymal transition (EMT). In addition, EIF4A3, an RNA-binding protein (RBP), could inhibit the formation of circRNA_100290 by binding to the flanking sites of circRNA_100290. Low EIF4A3 expression in GC was related to a poor prognosis.ConclusionsElevated circRNA_100290 expression in GC promotes cell proliferation, invasion and EMT via the miR-29b-3p/ITGA11 axis and might be regulated by EIF4A3. CircRNA_100290 might be a promising biomarker and target for GC therapy.Graphical abstract

Role of the epithelial-mesenchymal transition-related circular RNA, circ-10720, in non-small-cell lung cancer.

BackgroundCircular RNAs (circRNAs) are non-coding RNAs with a circular structure that have recently emerged as important regulators of tumorogenesis. Recently, several circRNAS, including circ-10720 have been related to epithelial-mesenchymal transition (EMT) process. In the present study, we have analyzed the role of circ-10720 in non-small-cell lung cancer (NSCLC) and studied its prognostic relevance in resected stage I–IIIa NSCLC patients.MethodsCirc-10720 expression was analyzed using a custom TaqMan assay in four NSCLC cell lines (HCC44, A549, H23 and H1299) and in the normal immortalized lung cell line BEAS2B. Silencing of circ-10720 was performed using two custom siRNAs which were transfected using lipofectamine 2000. Protein levels were evaluated by Western blot and immunofluorescence. Wound healing and invasion assays were performed to evaluate the impact the circRNA on cell motility. Apoptosis was analyzed by evaluation of Caspase 3–7 activity and proliferation by MTS assay. Moreover, the expression levels of the circRNA were studied in 119 resected NSCLC patients. The expression in tumor tissue was correlated with the main clinicopathological characteristics and with time to relapse (TTR).ResultsCirc-10720 was overexpressed in HCC44 and A549 and underexpressed in H23 and H1299 NSCLC cell lines in comparison to BEAS2B normal immortalized lung cell line. CircRNA knockdown in the two circ-10720 overexpressing cell lines was associated with a decrease of Vimentin (VIM) and an increase of E-cadherin (CDH1) protein levels, loss of mesenchymal phenotype, and a significant reduction of migration and invasion capacity. After silencing circ-10720, the apoptosis rate increased and the proliferation was significantly reduced. Furthermore, circ-10720 was upregulated in tumor vs. normal tissue from 119 resected NSCLC patients. In the group of patients not receiving adjuvant treatment, those with high levels of circ-10720 had a shorter TTR than those with low levels and emerged as an independent prognostic value in the multivariate analysis. In tumor tissue, circ-10720 levels positively correlated with the EMT gene Twist1 levels.ConclusionsCirc-10720 regulates EMT, apoptosis and proliferation and acts as a biomarker of relapse in NSCLC.

CircRNA_103801 accelerates proliferation of osteosarcoma cells by sponging miR-338-3p and regulating HIF-1/Rap1/PI3K-Akt pathway.

This study aimed to investigate the roles of hsa_circRNA_103801 in the progression of osteosarcoma (OS) cells. Quantitative reverse transcription-polymerase chain reaction (RT-qPCR) was used to detect the expression level of circRNA_103801 in OS cells. Cell count kit-8 and Transwell migration and invasion assays were employed to detect the proliferation, migration, and invasion abilities of OS cells. The effects of circRNA_103801 on the apoptosis of OS cells were identified by flow cytometry. The binding relationship between circRNA_103801 and miR-338-3p was verified by bioinformatics analysis. MiR-338-3p level in OS cell lines was detected by RT-qPCR. Additionally, Western blotting was utilized to detect the expression levels of HIF-1, Rap1, PI3K, and Akt in OS cells. The results showed that the expression level of circRNA_103801 was significantly up-regulated in OS patients' tissues. Inhibiting the expression level of circRNA_103801 could attenuate the proliferation, migration, and invasion abilities of OS cells. In addition, the down-regulated expression level of circRNA_103801 could induce cell apoptosis. The results of the luciferase reporter assay suggested that circRNA_103801 could be combined with miR-338-3p, and the RT-qPCR revealed that the miR-338-3p level in OS cells after knockdown of circRNA_103801 was elevated compared with the control group. The results of Western blotting suggested that the expression levels of HIF-1, Rap1, PI3K, and Akt were elevated in OS cells. In conclusion, the circRNA_103801-miR-3388-3p-HIF-1/Rap1/PI3K-Akt pathway could be a therapeutic target of OS.

Optimized RNA-targeting CRISPR/Cas13d technology outperforms shRNA in identifying functional circRNAs

Short hairpin RNAs (shRNAs) are used to deplete circRNAs by targeting back-splicing junction (BSJ) sites. However, frequent discrepancies exist between shRNA-mediated circRNA knockdown and the corresponding biological effect, querying their robustness. By leveraging CRISPR/Cas13d tool and optimizing the strategy for designing single-guide RNAs against circRNA BSJ sites, we markedly enhance specificity of circRNA silencing. This specificity is validated in parallel screenings by shRNA and CRISPR/Cas13d libraries. Using a CRISPR/Cas13d screening library targeting > 2500 human hepatocellular carcinoma-related circRNAs, we subsequently identify a subset of sorafenib-resistant circRNAs. Thus, CRISPR/Cas13d represents an effective approach for high-throughput study of functional circRNAs.

CircRNA circ_102049 Implicates in Pancreatic Ductal Adenocarcinoma Progression through Activating CD80 by Targeting miR-455-3p.

Emerging evidence has shown that circular RNAs (circRNAs) and DNA methylation play important roles in the causation and progression of cancers. However, the roles of circRNAs and abnormal methylation genes in the tumorigenesis of pancreatic ductal adenocarcinoma (PDAC) are still largely unknown. Expression profiles of circRNA, gene methylation, and mRNA were downloaded from the GEO database, and differentially expressed genes were obtained via GEO2R, and a ceRNA network was constructed based on circRNA-miRNA pairs and miRNA-mRNA pairs. Inflammation-associated genes were collected from the GeneCards database. Then, functional enrichment analysis and protein-protein interaction (PPI) networks of inflammation-associated methylated expressed genes were investigated using Metascape and STRING databases, respectively, and visualized in Cytoscape. Hub genes of PPI networks were identified using the NetworkAnalyzer plugin. Also, we analyzed the methylation, protein expression levels, and prognostic value of hub genes in PDAC patients through the UALCAN, Human Protein Atlas (HPA), and Kaplan-Meier plotter databases, respectively. The circRNA_102049/miR-455-3p/CD80 axis was identified by the ceRNA network and hub genes. In vitro and in vivo experiments were performed to evaluate the functions of circRNA_102049. The regulatory mechanisms of circRNA_102049 and miR-455-3p were explored by RT-PCR, western blot, and dual-luciferase assays. In the present study, twelve hub genes (STAT1, CCND1, KRAS, CD80, ICAM1, ESR1, RAF1, RPS6KA2, KDM6B, TNRC6A, FOSB, and DNM1) were determined from the PPI networks. Additionally, the circRNA_102049 was upregulated in PDAC cell lines. Functionally, the knockdown of circRNA_102049 by siRNAs inhibited cell growth, inflammatory factors, and migratory and invasive potential and promoted cell apoptosis. Mechanistically, circRNA_102049 functioned as a sponge of miR-455-3p and partially reversed the effect of miR-455-3p and consequently upregulated CD80 expression. Our findings showed that circRNA_102049 and methylated hub genes play an important role in the proliferation, apoptosis, migration, invasion, and inflammatory response of PDAC, which might be selected as a promising prognostic marker and therapeutic target for PDAC.

CircRNA_100920 enhanced oncolytic adenovirus therapy in colon cancer by suppressing IFN-γ expression

Colon cancer (CRC) is one of the leading causes of tumor lethality in the world. CRC is mostly diagnosed at advanced stages of disease, and chemotherapy is one of the major options in treating the advanced CRC patients. However, the development of multi-drug resistance has become the obstacle to an effective control of CRC clinically. Thus, it is essentially significant for scientists and medical doctors to explore new strategies for CRC therapy. CircRNA_100920 expression was upregulated in CRC tissues and cells. Knockdown of circRNA_100920 inhibited cell proliferation in CRC cells. Clinically, circRNA_100920 was associated with survival rate, metastasis, TNM stage and tumor size. Notably, circRNA_100920 could become a potential biomarker by the receiver operating characteristic curve analysis. In addition, circRNA_100920 enhanced oncolytic adenovirus therapy in colon cancer by suppressing IFN-γ expression. CircRNA_100920, as a biomarker, may participate in the diagnosis, treatment, and prognosis of CRC.

Experimental Strategies for Studying the Function of Plant CircRNAs.

Circular RNAs (circRNAs) represent a novel group of noncoding RNA whose functions are little known in plants. Genetic manipulation is necessary for studying the biological function of specific circRNA. Here, we describe strategies to study the function of plant circRNAs including artificial microRNA-mediated circRNA knockdown, gain-of-function study, full-length circRNA identification, and circRNA-protein interaction. These methods can be applied to functional characterization of circRNAs in plants and would be promising to facilitate the research on plant circRNAs.

CircRNA_010383 Acts as a Sponge for miR-135a and its Downregulated Expression Contributes to Renal Fibrosis in Diabetic Nephropathy.

Diabetic nephropathy (DN), a vascular complication of diabetes mellitus, is the leading cause of death in diabetic patients. The contribution of aberrantly expressed circRNAs to diabetic nephropathy in vivo is poorly understood. Integrated comparative circRNA microarray profiling was used to examine the expression of circRNAs in diabetic kidney of db/db mice. We found that circRNA_010383 expression was markedly downregulated in diabetic kidneys, mesangial cells and tubular epithelial cells cultured in high-glucose conditions. circRNA_010383 colocalized with microRNA-135a (miR-135a) and inhibited miR-135a function by directly binding to miR-135a. In vitro, the knockdown of circRNA_010383 promoted the accumulation of extracellular matrix (ECM) proteins and downregulated the expression of transient receptor potential cation channel, subfamily C, member (TRPC1), which is a target protein of miR-135a. Furthermore, circRNA_010383 overexpression effectively inhibited the high-glucose-induced accumulation of ECM and increased TRPC1 levels in vitro More importantly, the kidney-target of circRNA_010383 overexpression inhibited proteinuria and renal fibrosis in db/db mice. Mechanistically, we identified that a loss of circRNA_010383 promoted proteinuria and renal fibrosis in DN by acting as a sponge for miRNA-135a. This study reveals that circRNA_010383 may be a novel therapeutic target for DN in the future.

CircRNA_010383 Acts as a Sponge for miR-135a, and Its Downregulated Expression Contributes to Renal Fibrosis in Diabetic Nephropathy.

Diabetic nephropathy (DN), a vascular complication of diabetes, is the leading cause of death in patients with diabetes. The contribution of aberrantly expressed circular RNAs (circRNAs) to DN in vivo is poorly understood. Integrated comparative circRNA microarray profiling was used to examine the expression of circRNAs in diabetic kidney of db/db mice. We found that circRNA_010383 expression was markedly downregulated in diabetic kidneys, mesangial cells, and tubular epithelial cells cultured in high-glucose conditions. circRNA_010383 colocalized with miRNA-135a (miR-135a) and inhibited miR-135a function by directly binding to miR-135a. In vitro, the knockdown of circRNA_010383 promoted the accumulation of extracellular matrix (ECM) proteins and downregulated the expression of transient receptor potential cation channel, subfamily C, member 1 (TRPC1), which is a target protein of miR-135a. Furthermore, circRNA_010383 overexpression effectively inhibited the high-glucose-induced accumulation of ECM and increased TRPC1 levels in vitro. More importantly, the kidney target of circRNA_010383 overexpression inhibited proteinuria and renal fibrosis in db/db mice. Mechanistically, we identified that a loss of circRNA_010383 promoted proteinuria and renal fibrosis in DN by acting as a sponge for miR-135a. This study reveals that circRNA_010383 may be a novel therapeutic target for DN in the future.

Circular RNA circ_PVT1 induces epithelial-mesenchymal transition to promote metastasis of cervical cancer.

Cervical cancer is one of the most common gynecological malignant tumors. At present, it has been confirmed that the occurrence and development of cervical cancer is related to human papillomavirus infection. As a new regulatory molecule and research hotspot, circRNA is abnormally expressed in tumors and other diseases, and is expected to become a new biomarker for diagnosis and prediction of tumor occurrence and development. In this research, bioinformatics analysis and RT-PCR analysis showed that hsa_circ_0009143 (circRNA_PVT1) was up-regulated in cervical cancer. Knockdown of circRNA_PVT1 inhibits the migration and invasion of cervical cancer cells and would prevent pulmonary metastasis. Overexpression of circRNA_PVT1 induced migration and invasion of cervical cancer cells, which would result in the promotion of pulmonary metastasis. Finally, we found that circRNA_PVT1 can induce EMT of cervical cancer cells via targeting miR-1286 by exosome pathway, which can be a novel mechanism of cervical cancer progression.

CircRNA_09505 aggravates inflammation and joint damage in collagen-induced arthritis mice via miR-6089/AKT1/NF-\u03baB axis

A number of circular RNAs (circRNAs) have been implicated in rheumatoid arthritis (RA) pathogenesis; however, little is known about their function and hidden molecular mechanism in immune and inflammation regulation. We investigated the role and the underlying mechanism of circRNA_09505 in RA in this study. Real-time PCR and fluorescence in situ hybridization (FISH) are adopted to estimate the quantitative expression and localization of circRNA_09505 in macrophages. The altering effect of circRNA_09505 on inflammation is investigated in vitro and in vivo by use of macrophage cell models and collagen-induced arthritis (CIA) mice. Luciferase reporter assay and RNA-binding protein immunoprecipitation (RIP) are used to confirm the circRNA_09505/miR-6089 ceRNA network predicted by bioinformatics analysis. Compared with controls, the expression of circRNA_09505 is upregulated in peripheral blood mononuclear cells (PBMCs) from patients with RA. The proliferation and cell cycle are significantly promoted when circRNA_09505 is upregulated in macrophages, whereas knockdown of circRNA_09505 inhibits macrophage proliferation and cell- cycle progression. Besides, circRNA_09505 can act as a miRNA sponge for miR-6089 in macrophages, and promote the production of TNF-α, IL-6, and IL-12 through ceRNA mechanism. Moreover, AKT1 is a direct target of miR-6089. CircRNA_09505 can promote AKT1 expression by acting as a miR-6089 sponge via IκBα/NF-κB signaling pathway in macrophages. Most interestingly, knockdown of circRNA_09505 significantly alleviates arthritis and inflammation in vivo in CIA mice. These data support the hypothesis that circRNA_09505 can function as a miR-6089 sponge and regulate inflammation via miR-6089/AKT1/NF-κB axis in CIA mice.

Hsa_circRNA_100146 Acts as a Sponge of miR-149-5p in Promoting Bladder Cancer Progression via Regulating RNF2.

BackgroundMounting evidence has demonstrated that circular RNAs (circRNAs) play indispensable roles in the progression of bladder cancer. Public database mining showed that hsa_circRNA_100146 (circRNA_100146) was highly expressed in bladder cancer. This study aimed to characterize the biological role of circRNA_100146 and clarify the underlying mechanism in bladder cancer.MethodsWe evaluated the relationship between circRNA_100146 expression and clinicopathological features. Furthermore, gain- and loss-of-function studies were conducted in bladder cancer cells via transfection with gene-carrying plasmids (over-expression) or specific short hairpin RNAs (knockdown). Moreover, computational algorithms and dual-luciferase reporter assays were performed to explore the possible mechanisms of action. Additionally, in vivo xenograft experiments were performed to further analyze the effect of circRNA_100146 on tumor growth.ResultsOur data showed that circRNA_100146 expression was increased in bladder cancer tissues and cell lines, and that high expression of circRNA_100146 was correlated with poor patient prognosis. Upregulation of circRNA_100146 promoted cell proliferation, migration, and invasion, and inhibited cell apoptosis, whereas knockdown of circRNA_100146 displayed opposite effects on bladder cancer cells. Notably, circRNA_100146 could combine with miR-149-5p and promote ring finger protein 2 (RNF2) expression, thereby facilitating the progression of bladder cancer. Furthermore, overexpression of RNF2 reversed the effects of circRNA_100146 knockdown on the biological behaviors of bladder cancer cells. The in vivo experiments revealed that downregulation of circRNA_100146 dramatically delayed tumor growth.ConclusionOur findings indicate that circRNA_100146 functions as a sponge of miR-149-5p in promoting bladder cancer progression by regulating RNF2 expression and that circRNA_100146 may serve as a novel biomarker in human bladder cancer.

CircRNA_104889 promotes lung adenocarcinoma cell invasion via sponging miR4458

BackgroundLung adenocarcinoma is metastatic cancer with a high mortality rate. Circular RNAs (circRNAs) are a type of noncoding RNA and play a vital role in cancer progression. However, the expression and function of circRNAs in lung adenocarcinoma are still mostly unknown.MethodsIn this study, we screened the differential expression of circRNAs in human bronchial epithelial cells (HBE) and A549 human lung adenocarcinoma cell line (A549) by human circRNA microarray and RT-qPCR. The role of overexpressed circRNA_104889 in A549 cell proliferation, apoptosis, migration, and invasion was studied extensively. Intracellular localization of circRNA_104889 was visualized by FISH assay. MiRNA sponging, ERK1/2 signaling, and caspase-3 expression were analyzed in siRNA-mediated circRNA_104889 knockdowned A549 cells.ResultsCircRNA microarray showed overexpression of circRNA_104889 (> 13-fold) in A459 cells compared to HBE. This finding was further corroborated by the RT-qPCR result. CircRNA_104889 was mainly localized in the cytoplasm of A549 cells. The knockdown of circRNA_104889 in A549 cells by si-RNA mediated RNA interference did not affect cell proliferation and apoptosis but significantly inhibited cell migration and invasion in vitro. Furthermore, knockdown of circRNA_104889 led to an increase of miR4458 expression. Overexpression of miR4458 inhibited A549 cell migration. Both the knockdown of circRNA_104889 and overexpression of miR4458 inhibited the caspase-3 expression and ERK1/2 phosphorylation in A549 cells.ConclusionsCircRNA_104889 promotes lung adenocarcinoma cell migration and invasion by sponging miR4458 and targeting ERK1/2 signaling and caspase-3 expression.

Effects of circRNA_103993 on the proliferation and apoptosis of NSCLC cells through miR-1271/ERG signaling pathway.

Non-small cell lung cancer (NSCLC) accounts for more than 80% of lung cancer. CircRNA is a new type of non-coding RNA. CircRNA was found to be deeply involved in the regulation of NSCLC cells. However, the principle of CircRNA regulating NSCLC cells needs to be further explored. The relative mRNA expression levels of CircRNA_103993, miR-1271 and ERG were detected by quantificational real-time polymerase chain reaction (qRT-PCR) in NSCLC cells and human bronchial epithelial cell line HBE. Cell proliferation was detected by the Cell Counting Kit (CCK8) when NSCLC cells were transfected with si-CircRNA_103993, si-NC, miR-1271 mimics, miR-NC, LV-ERG, respectively. The apoptotic rate of NSCLC cells was measured by apoptotic assay and flow Cytometry. The relative mRNA and protein expression levels of PCNA and caspase-3 were detected by Western blot and qRT-PCR. CircRNA_103993 and ERG were significantly up-regulated while miR-1271 was significantly down-regulated in NSCLC cells. Knockdown of CircRNA_103993 and high expression of miR-1271 significantly inhibited NSCLC cell proliferation and promoted apoptosis. The double luciferin report showed that CircRNA_103993 served as a sponge of miR-1271 and miR-1271 could directly target ERG in NSCLC cells. More importantly, low expression of CircRNA_103993 increased the expression level of miR-1271, and high expression of miR-1271 decreased the expression level of ERG. Further experiments showed that miR-1271 inhibitors reversed the effect of si-CircRNA_103993 on proliferation and apoptosis of NSCLC cells. However, miR-1271 mimics significantly promoted the effects of si-CircRNA_103993 on the proliferation and apoptosis. Moreover, LV-ERG reversed the effect of miR-1271 mimics on proliferation and apoptosis of NSCLC cells. However, si-ERG significantly promoted the effects of miR-1271 mimics on the proliferation and apoptosis. CircRNA_103993 was highly expressed in NSCLC cells. CircRNA_103993 regulated proliferation and apoptosis of NSCLC cells by acting as a sponge of miR-1271. The CircRNA_103993 /miR-1271/ ERG axis had an important effect on the proliferation and apoptosis of NSCLC cells. Therefore, CircRNA_103993 may be a target for treating lung cancer.

CircRNA_002178 promotes the proliferation and migration of oral squamous cell carcinoma cells by activating the Akt/mTOR pathway.

We aimed to investigate the biological effects of circRNA_002178 in oral squamous cell carcinoma (OSCC) tissues and to analyze its potential mechanism. CircRNA_002178 expression in 50 pairs of OSCC tissues and adjacent ones was studied by quantitative polymerase chain reaction (qPCR) analysis, and the correlations of circRNA_002178 with clinicopathological indicators, as wells as prognosis of OSCC patients were analyzed. qPCR was used to verify circRNA_002178 expression in OSCC cell lines. Subsequently, circRNA_002178 knockdown models were constructed using lentivirus in OSCC cell lines, and the impacts of circRNA_002178 on the function of OSCC cells were assessed by cell counting kit-8 (CCK-8) test, plate cloning experiment, transwell assay and nude mouse tumor formation experiments. Finally, rescue experiments in vitro were used to explore the potential mechanism of circRNA_002178 activating Akt/mTOR pathway. Our data showed that circRNA_002178 expression in OSCC tissue specimens was remarkably higher than that in adjacent ones. In comparison to patients in low circRNA_002178 expression group, patients in high expression group showed higher incidences of advanced pathological stage and distant metastasis, and a lower overall survival rate. Cell functional experiments revealed that knockdown of circRNA_002178 markedly attenuated the proliferation and migration ability of OSCC cells compared to the sh-NC group, and the consistent results were observed in the nude mouse experiment. In addition, Western blot suggested that the expression of key proteins in Akt/mTOR signaling pathway was remarkably reduced after downregulation of circRNA_002178 in OSCC cells. Meanwhile, Akt activator SC79 reversed the inhibitory effect of circRNA_002178 on the metastasis and proliferation of OSCC cells. CircRNA_002178, over-expressed in OSCC tissues and cell lines, may promote the malignant progression of OSCC through activating the Akt/mTOR signaling pathway.

CircRNA_MYLK promotes malignant progression of ovarian cancer through regulating microRNA-652.

The purpose of this study was to investigate circRNA_MYLK level in ovarian cancer (OC), and to further investigate whether it could promote the malignant progression of OC via regulating microRNA-652. quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) was performed to examine circRNA_MYLK level in 46 tumor tissue specimens and paracancerous normal ones collected from OC patients, and the interplay between circRNA_MYLK expression and clinical indicators of OC and patient prognosis was analyzed. Meanwhile, qPCR was also used to further verify circRNA_MYLK level in OC cell lines. In addition, circRNA_MYLK knockdown model was constructed using lentivirus in OC cell lines including A2780 and CAOV3, and the impacts of circRNA_MYLK on the biological functions of OC cells was evaluated using Cell Counting Kit-8 (CCK-8) and cloning experiments. Finally, Luciferase reporting assay and recovery experiment were performed to investigate the regulatory interplay between circRNA_MYLK and microRNA-652. qPCR results indicated that circRNA_MYLK level in OC patients was remarkably higher than that in adjacent ones, and the difference was statistically significant. Compared with patients with low expression of circRNA_MYLK, patients with high expression of circRNA_MYLK had a higher pathological staging and a lower overall survival rate. Compared with the control group (sh-NC), the OC cell proliferation ability was remarkably attenuated in the circRNA_MYLK knockdown group (sh-circRNA). In addition, qPCR verification revealed that the expression levels of microRNA-652 and circRNA_MYLK were negatively correlated in OC tissues. At the same time, bioinformatics analysis and Luciferase reporter gene assay results confirmed that circRNA_MYLK can be targeted by microRNA-652. Finally, it was found that simultaneous knockdown of circRNA_MYKK and microRNA-652 could reverse the enhanced OC cell proliferative capacity induced by downregulation of circRNA_MYLK alone. CircRNA_MYLK may promote the malignant progression of OC via regulating microRNA-652, and its expression was remarkably associated with pathological staging and poor prognosis in patients with OC.

CircRNA_0084043 contributes to the progression of diabetic retinopathy via sponging miR-140-3p and inducing TGFA gene expression in retinal pigment epithelial cells

Diabetic retinopathy (DR) is a frequent complication of diabetes and it can lead to visual impairment and blindness. However, the mechanism of their regulation remains little known. circRNAs can function as crucial competing endogenous RNA, which can sponge corresponding miRNAs and affect mRNA expression in various diseases, including DR. In our current research, we observed that circRNA_0084043 was elevated in high glucose (HG)-incubated ARPE-19 cells. Then, we focused on whether and how circRNA_0084043 participated in retinal vascular dysfunction under conditions diabetes. Apoptosis, inflammation and oxidative stress are hallmark of DR progression. This work was aimed to investigate the signaling mechanisms of circRNA_0084043 in these pathogenesis of DR. We discovered loss of circRNA_0084043 significantly increased cell survival and repressed HG-triggered apoptosis. In addition, knockdown of circRNA_0084043 remarkably reduced oxidative stress as evidenced by the down-regulated malondialdehyde (MDA) content, enhanced activities of Super Oxide Dismutase (SOD) and Glutathione peroxidase (GSH-PX). Addition, silence of circRNA_0084043 effectively restrained HG-stimulated inflammation as proved by repressing inflammatory cytokines Tumor Necrosis Factor α (TNF-α), Interleukin 6 (IL-6) and Cox-2 in ARPE-19 cells. Subsequently, we successfully predicted that miR-140-3p was a downstream target of circRNA_0084043, which could be negatively regulated by circRNA_0084043. Mechanistically, loss of miR-140-3p abrogated the beneficial effects of circRNA_0084043 siRNA on ARPE-19 cells. Transforming Growth Factor alpha (TGFA) can exhibit a role in multiple diseases. Taken these together, these data demonstrated that loss of circRNA_0084043 depressed HG-induced damage via sponging miR-140-3p and regulating TGFA.

CircRNA_0058063 functions as a ceRNA in bladder cancer progression via targeting miR-486-3p/FOXP4 axis.

Emerging evidence has uncovered critical regulatory roles of circular RNAs (circRNAs) function as dynamic scaffolding molecules in tumorigenesis and progression. However, the aberrant expression and clinical significance of hsa_circ_0058063 (circRNA_0058063) in bladder cancer (BC) remain poorly understood. circRNA expression was analyzed via a microarray in cancerous tissue and non-carcinoma tissues. Luciferase reporter assays and RNA immunoprecipitation (RIP) were both conducted to uncover the function of circRNA_0058063 in BC. circRNA_0058063 was overexpressed in BC tissues compared with adjacent normal tissues. Knockdown of circRNA_0058063 dramatically decreased cell proliferation and invasion, and promoted apoptosis in 5637 and BIU-87 cell lines. Furthermore, mechanistic investigations showed that circRNA_0058063 and FOXP4 could directly bind to miR-486-3p, demonstrating that circRNA_0058063 regulated FOXP4 expression by competitively binding to miR-486-3p. Taken together, circRNA_0058063 functions by sponging miR-486-3p in BC progression, which could act as a new biomarker and further developed to be a therapeutic target in BC.

CircRNA_103762 promotes multidrug resistance in NSCLC by targeting DNA damage inducible transcript 3 (CHOP).

BackgroundCircRNAs have been found to play crucial roles in multiple tumor including non‐small cell lung cancer (NSCLC). Here, we researched the correlation between circRNA_103762 and chemotherapy resistance.MethodsRT‐PCR assay was performed to detect circRNA_103762 and DNA damage inducible transcript 3 (CHOP) expression. CCK8 assay was performed to examine cell proliferation and IC50 of different drug. Migration and invasion assay was used to detect cell migration and invasion.ResultsIn our study, circRNA_103762 expression was upregulated in NSCLC tissues and cell. Knockdown of circRNA_103762 can inhibited cell proliferation, migration and invasion in NSCLC. In addition, downregulation of circRNA_103762 promoted CHOP expression and inhibited multidrug resistance (MDR) in NSCLC.ConclusionTogether, we demonstrated that circRNA_103762 is upregulated in NSCLC and functions as an oncogene in NSCLC, and circRNA_103762 enhanced MDR by inhibited CHOP expression in NSCLC cells. These results will help us understand the MDR of NSCLC, providing better effective therapy strategies for patients.

Circular RNA Profiling Reveals That circRNA_104433 Regulates Cell Growth by Targeting miR-497-5p in Gastric Cancer.

BackgroundThe role and mechanism of hsa_circRNA_104433 in gastric cancer (GC) are further elucidated.Materials and methodsCircRNA_104433 was selected by circRNA microarrays and GEO database. qRT-PCR was used to analyze the expression of circRNA_104433 in GC. The role of circRNA_104433 in GC cells was evaluated based on cell cycle progression, cell proliferation, cell apoptosis, and tumor xenograft experiment assay. To explore the mechanisms of circRNA_104433 in GC TCGA database, STRING version, qRT-PCR and luciferase assay were performed. Furthermore, the prognostic value of CDC25A in GC was determined based on the GEO database.ResultsThe level of circRNA_104433 showed upregulation in GC tissues, and the expression of it showed a positive correlation with the degree of differentiation and the size of the tumor. Knockdown of circRNA_104433 inhibited cell cycle transition, and cell proliferation, while promoted cell apoptosis in GC. CircRNA_104433 directly binds to miR-497-5p, which directly regulates CDC25A. The median survival period of GC patients with high expression levels of CDC25A was 21.3 months, which was shorter than those with low group expression of CDC25A (35.9 months). The cell cycle proteins CDK1, CDK2, CCNB1, PKMYT1, CDC20, CHEK1 and CDC25A were coexpressed with CDC25A.ConclusionThese findings suggested that knockdown of circRNA_104433 expression suppressed tumor development in GC.