ceRNA Mechanism Research Articles

Circ_0003747 promotes thyroid cancer progression by sponging miR-338-3p to upregulate PLCD3 expression

ABSTRACT The circular RNAs (circRNAs) involved in competitive endogenous RNA (ceRNA) mechanism are critical modulators affecting pathogenesis of thyroid carcinoma (TC). The study’s goal was to investigate the effects of circ 0003747 on the biological progression of papillary thyroid cancer (PTC). Normal thyroid cells Nthy-ori3–1 and TC derived cell lines were used in our study. Sanger sequencing and RNase R treatment were utilized for validating the circular structure of circ_0003747. In our work, circ_0003747 was found to be highly expressed in TC cells. Circ_0003747 knockdown reduced TC cell viability, proliferation, migration, and invasion while increasing cell apoptosis. Circ_0003747 targeted and negatively regulated miR-338-3p expression. Besides, miR-338-3p interacted with PLCD3 to repress its expression. Overexpression of miR-338-3p inhibited TC cell progression, and PLCD3 reversed these effects. Furthermore, PLCD3 overexpression reversed the effects of circ_0003747 knockdown on TC cells. Additionally, the knockdown of circ_0003747 remarkably suppressed tumour size and growth, restrained PLCD3 expression and promoted miR-338-3p expression in nude mice. In conclusion, circ_0003747 facilitated the biological progression of TC by modulating the miR-338-3p/PLCD3 axis, and it may be a new target for TC treatment. Abbreviations: TC: Thyroid carcinoma; PTC: Papillary thyroid carcinoma; CircRNAs: Circular RNAs; MiRNA: MicroRNA; EMT: Epithelial-mesenchymal transition; HCC: Hepatocellular carcinoma; PLCD3: Phospholipase C Delta 3; CeRNA: Competitive endogenous RNA

CircRNAs in osteoarthritis: research status and prospect.

Osteoarthritis (OA) is the most common joint disease globally, and its progression is irreversible. The mechanism of osteoarthritis is not fully understood. Research on the molecular biological mechanism of OA is deepening, among which epigenetics, especially noncoding RNA, is an emerging hotspot. CircRNA is a unique circular noncoding RNA not degraded by RNase R, so it is a possible clinical target and biomarker. Many studies have found that circRNAs play an essential role in the progression of OA, including extracellular matrix metabolism, autophagy, apoptosis, the proliferation of chondrocytes, inflammation, oxidative stress, cartilage development, and chondrogenic differentiation. Differential expression of circRNAs was also observed in the synovium and subchondral bone in the OA joint. In terms of mechanism, existing studies have mainly found that circRNA adsorbs miRNA through the ceRNA mechanism, and a few studies have found that circRNA can serve as a scaffold for protein reactions. In terms of clinical transformation, circRNAs are considered promising biomarkers, but no large cohort has tested their diagnostic value. Meanwhile, some studies have used circRNAs loaded in extracellular vesicles for OA precision medicine. However, there are still many problems to be solved in the research, such as the role of circRNA in different OA stages or OA subtypes, the construction of animal models of circRNA knockout, and more research on the mechanism of circRNA. In general, circRNAs have a regulatory role in OA and have particular clinical potential, but further studies are needed in the future.

Long non-coding RNA crnde promotes deep vein thrombosis by sequestering miR-181a-5p away from thrombogenic Pcyox1l

BackgroundDeep vein thrombosis (DVT) is an interplay of genetic and acquired risk factors, where functional interactions in lncRNA-miRNA-mRNA ceRNA networks contribute to disease pathogenesis. Based on the high-throughput transcriptome sequencing prediction, we have assessed the contribution of lncRNA Crnde/miR-181a-5p/Pcyox1l axis to thrombus formation.MethodsDVT was modeled in mice by inferior vena cava stenosis, and inferior vena cava tissues were harvested for high-throughput transcriptome sequencing to screen differentially expressed lncRNAs and mRNAs. The key miRNA binding to Crnde and Pcyox1l was obtained through searching the RNAInter and mirWalk databases. The binding affinity between Crnde, miR-181a-5p, and Pcyox1l was examined by FISH, dual luciferase reporter gene, RNA pull-down, and RIP assays. Functional experiments were conducted in DVT mouse models to assess thrombus formation and inflammatory injury in inferior vena cava.ResultsIt was noted that Crnde and Pcyox1l were upregulated in the blood of DVT mice. Crnde competitively bound to miR-181a-5p and inhibited miR-181a-5p expression, and Pcyox1l was the downstream target gene of miR-181a-5p. Silencing of Crnde or restoration of miR-181a-5p reduced inflammatory injury in the inferior vena cava, thus curtailing thrombus formation in mice. Ectopic expression of Pcyox1l counterweighed the inhibitory effect of Crnde silencing.ConclusionsTherefore, Crnde sequesters miR-181a-5p to release Pcyox1l expression via ceRNA mechanism, thus aggravating thrombus formation in DVT.

The 2210408F21Rik/miR-1968–5p/Hras axis regulates synapse-related proteins in a mouse model of depressive-like behaviors through a ceRNA mechanism

Abnormal expression of long non-coding RNAs (lncRNAs) has been correlated with depressive disorders, but limited data are available on the lncRNA-microRNA (miRNA/miR)-messenger RNA (mRNA) competitive endogenous RNA (ceRNA) mechanism in depression. Herein, we address this issue based on transcriptome sequencing and in vitro experiments. Mouse hippocampus tissues were obtained from chronic unpredictable mild stress (CUMS)-induced mice to screen out differentially expressed mRNAs and lncRNAs based on the transcriptome sequencing. Next, the depression-related differentially expressed genes (DEGs) were obtained, followed by Gene Ontology (GO) and Kyoto Encylopedia of Genes and Genomes (KEGG) enrichment analysis. A total of 1018 differentially expressed mRNAs, 239 differentially expressed lncRNAs, and 58 DEGs related to depression were acquired. The miRNAs targeting Harvey rat sarcoma virus oncogene (Hras) and miRNAs sponged by Hras-related lncRNA were intersected to identify the ceRNA regulatory network. In addition, the synapse-related genes related to depression were acquired by bioinformatics analysis. Hras was identified as the core gene related to depression, mainly related to neuronal excitation. We also found that 2210408F21Rik competitively bound to miR-1968–5p that targeted Hras. The effects of 2210408F21Rik/miR-1968–5p/Hras axis on neuronal excitation were verified in primary hippocampal neurons. The experimental data indicated that the downregulation of 2210408F21Rik increased the level of miR-1968–5p to diminish Hras expression, thereby affecting neuronal excitation in CUMS mice. In conclusion, the 2210408F21Rik/miR-1968–5p/Hras ceRNA network can potentially affect the expression of synapsia-related proteins and is a promising target for preventing and treating depression.

Genome-wide analysis of circular RNA-mediated ceRNA regulation in porcine skeletal muscle development

BackgroundAs a diverse and abundant class of endogenous RNAs, circular RNAs (circRNAs) participate in various biological processes including cell proliferation and apoptosis. Nevertheless, few researchers have investigated the role of circRNAs in muscle development in cultivated pigs.ResultsIn this study, we used RNA-seq to construct circRNA expression profiles in skeletal muscle of Jinfen White pigs at the age of 1, 90, and 180 days. Among the 16,990 identified circRNAs, 584 circRNAs were differentially expressed. Moreover, the enrichment analysis of DE circRNA host genes showed that they were mainly involved in muscle contraction, muscle organ development and muscle system processes, as well as AMPK and cAMP-related signal pathways. We also constructed a circRNA–miRNA–mRNA co-expression network to find key circRNAs which many involved in the regulation of porcine skeletal muscle development through the competitive endogenous RNA (ceRNA) mechanism. It is noteworthy that circ_0018595/miR-1343/PGM1 axis may play a regulatory role in the development of porcine skeletal muscle.ConclusionsThis study identified the circRNAs and present the circRNA expression profile in the development of pigs, revealed that DE circRNA host genes participate in different cell fates and enriched the porcine ceRNA network. Thus, this work will become a valuable resource for further in-depth study of the regulatory mechanism of circRNA in the development of porcine skeletal muscle.

Analysis and verification of the circRNA regulatory network RNO_CIRCpedia_ 4214/RNO-miR-667-5p/Msr1 axis as a potential ceRNA promoting macrophage M2-like polarization in spinal cord injury

BackgroundCircRNAs are involved in the pathogenesis of several central nervous system diseases. However, their functions and mechanisms in spinal cord injury (SCI) are still unclear. Therefore, the purpose of this study was to evaluate circRNA and mRNA expression profiles in the pathological setting of SCI and to predict the potential function of circRNA through bioinformatics.MethodsA microarray-based approach was used for the simultaneous measurement of circRNAs and mRNAs, together with qPCR, fluorescence in situ hybridization, western immunoblotting, and dual-luciferase reporter assays to investigate the associated regulatory mechanisms in a rat SCI model.ResultsSCI was found to be associated with the differential expression of 414 and 5337 circRNAs and mRNAs, respectively. Pathway enrichment analyses were used to predict the primary function of these circRNAs and mRNAs. GSEA analysis showed that differentially expressed mRNAs were primarily associated with inflammatory immune response activity. Further screening of these inflammation-associated genes was used to construct and analyze a competing endogenous RNA network. RNO_CIRCpedia_4214 was knocked down in vitro, resulting in reduced expression of Msr1, while the expression of RNO-miR-667-5p and Arg1 was increased. Dual-luciferase assays demonstrated that RNO_CIRCpedia_4214 bound to RNO-miR-667-5p. The RNO_CIRCpedia_4214/RNO-miR-667-5p/Msr1 axis may be a potential ceRNA that promotes macrophage M2-like polarization in SCI.ConclusionOverall, these results highlighted the critical role that circRNAs may play in the pathophysiology of SCI and the discovery of a potential ceRNA mechanism based on novel circRNAs that regulates macrophage polarization, providing new targets for the treatment of SCI.

CircPVT1 promotes ER‐positive breast tumorigenesis and drug resistance by targeting ESR1 and MAVS

The molecular mechanisms underlying estrogen receptor (ER)‐positive breast carcinogenesis and endocrine therapy resistance remain incompletely understood. Here, we report that circPVT1, a circular RNA generated from the lncRNA PVT1, is highly expressed in ERα‐positive breast cancer cell lines and tumor samples and is functionally important in promoting ERα‐positive breast tumorigenesis and endocrine therapy resistance. CircPVT1 acts as a competing endogenous RNA (ceRNA) to sponge miR‐181a‐2‐3p, promoting the expression of ESR1 and downstream ERα‐target genes and breast cancer cell growth. Furthermore, circPVT1 directly interacts with MAVS protein to disrupt the RIGI–MAVS complex formation, inhibiting type I interferon (IFN) signaling pathway and anti‐tumor immunity. Anti‐sense oligonucleotide (ASO)‐targeting circPVT1 inhibits ERα‐positive breast cancer cell and tumor growth, re‐sensitizing tamoxifen‐resistant ERα‐positive breast cancer cells to tamoxifen treatment. Taken together, our data demonstrated that circPVT1 can work through both ceRNA and protein scaffolding mechanisms to promote cancer. Thus, circPVT1 may serve as a diagnostic biomarker and therapeutic target for ERα‐positive breast cancer in the clinic.

LncRNA PVT1 delays skin photoaging by sequestering miR-551b-3p to release AQP3 expression via ceRNA mechanism.

Understanding human skin photoaging requires in-depth knowledge of the molecular and functional mechanisms. Human dermal fibroblasts (HDFs) gradually lose their ability to produce collagen and renew intercellular matrix with aging. Therefore, our study aims to reveal the mechanistic actions of a novel ceRNA network in the skin photoaging by regulating HDF activities. Photoaging-related genes were obtained in silico, followed by GO and KEGG enrichment analyses. Differentially expressed lncRNAs and miRNAs were screened from the GEO database to construct the ceRNA co-expression network. In skin photoaging samples, PVT1 and AQP3 were poorly expressed, while miR-551b-3p was highly expressed. The relationships among the lncRNA, miRNA and mRNA were explored through the ENCORI database and dual luciferase reporter assay. Mechanistically, PVT1 could sequester miR-551b-3p to upregulate the expression of AQP3, which further inactivated the ERK/p38 MAPK signaling pathway. HDFs were selected to construct an in vitro cell skin photoaging model, where the senescence, cell cycle distribution and viability of young and senescent HDFs were detected by SA-β-gal staining, flow cytometry and CCK-8 assay. In vitro cell experiments confirmed that overexpression of PVT1 or AQP3 enhanced viability of young and senescent HDFs and inhibited HDF senescence, while miR-551b-3p upregulation counteracted the effect of PVT1. In conclusion, PVT1-driven suppression of miR-551b-3p induces AQP3 expression to inactivate the ERK/p38 MAPK signaling pathway, thereby inhibiting HDF senescence and ultimately delaying the skin photoaging.

Hsa_circ_0017842 acts as a competing endogenous RNA to enhance the malignancy of gastric cancer.

Circular RNAs (circRNAs) have been shown to act as competing endogenous RNAs (ceRNAs) participating in the progression of gastric cancer (GC). Our study aimed to investigate whether hsa_circ_0017842 can affect the malignancy of GC in a ceRNA manner. Gene expression microarrays from GEO DataSets database, quantitative real-time polymerase chain reaction (qPCR) and western blotting were used to identify the expression levels of hsa_circ_0017842, miR-1294, and secreted protein, acidic and rich in cysteine (SPARC) in GC. The function of hsa_circ_0017842/miR-1294/SPARC axis in GC cells was confirmed using gainand loss-of-function assays. In addition, luciferase and RNA pulldown assays were performed to demonstrate the ceRNA mechanism of hsa_circ_0017842 involving miR-1294 and SPARC. The upregulation of hsa_circ_0017842 and SPARC, and downregulation of miR-1294 were observed in GC. Upregulating hsa_circ_0017842 in GC cells led to an increase in their proliferation, migration and invasion, and hsa_circ_0017842 knockdown showed the opposite effects on GC cells. Moreover, hsa_circ_0017842 was shown to be a sponge for miR-1294, thereby regulating SPARC expression. Due to the targeting relationship among hsa_circ_0017842, miR-1294 and SPARC, SPARC knockdown could relieve the effect of hsa_circ_0017842 overexpression on GC cells. Overall, this study confirmed that hsa_circ_0017842 acted as a ceRNA to promote the malignancy of GC cells through regulating the miR-1294/SPARC axis. Our findings might help better elucidate the molecular mechanism of GC tumorigenesis, and as a result improve the overall survival of GC patients.

Screening of core genes and prediction of ceRNA regulation mechanism of circRNAs in nasopharyngeal carcinoma by bioinformatics analysis.

Background: Nasopharyngeal carcinoma (NPC) represents a highly aggressive malignant tumor. Competing endogenous RNAs (ceRNA) regulation is a common regulatory mechanism in tumors. The ceRNA network links the functions between mRNAs and ncRNAs, thus playing an important regulatory role in diseases. This study screened the potential key genes in NPC and predicted regulatory mechanisms using bioinformatics analysis. Methods: The merged microarray data of three NPC-related mRNA expression microarrays from the Gene Expression Omnibus (GEO) database and the expression data of tumor samples or normal samples from the nasopharynx and tonsil in The Cancer Genome Atlas (TCGA) database were both subjected to differential analysis and Weighted Gene Co-expression Network Analysis (WGCNA). The results from two different databases were intersected with WGCNA results to obtain potential regulatory genes in NPC, followed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses. The hub-gene in candidate genes was discerned through Protein-Protein Interaction (PPI) analysis and its upstream regulatory mechanism was predicted by miRwalk and circbank databases. Results: Totally 68 upregulated genes and 96 downregulated genes in NPC were screened through GEO and TCGA. According to WGCNA, the NPC-related modules were screened from GEO and TCGA analysis results, and the genes in the modules were obtained. After the results of differential analysis and WGCNA were intersected, 74 differentially expressed candidate genes associated with NPC were discerned. Finally, fibronectin 1 (FN1) was identified as a hub-gene in NPC. Prediction of upstream regulatory mechanisms of FN1 suggested that FN1 may be regulated by ceRNA mechanisms involving multiple circRNAs, thereby influencing NPC progression through ceRNA regulation. Conclusion: FN1 is identified as a key regulator in NPC development and is likely to be regulated by numerous circRNA-mediated ceRNA mechanisms.

Six immune-related promising biomarkers may promote hepatocellular carcinoma prognosis: a bioinformatics analysis and experimental validation

BackgroundAbnormal miRNA and mRNA expression and dysregulated immune microenvironment have been found to frequently induce the progression of hepatocellular carcinoma (HCC) in recent reports. In particular, the immune-related competing endogenous RNAs (ceRNA) mechanism plays a crucial role in HCC progression. However, the underlying mechanisms remain unclear.MethodsDifferentially expressed immune-related genes were obtained from the Immport, GEO, and TCGA databases. The mRNA and protein expression levels in HCC tissues and adjacent normal tissues were confirmed, and we further investigated the methylation levels of these biomarkers to explore their function. Then, the TIMER and TISCH databases were used to assess the relationship between immune infiltration and hub genes. Survival analysis and univariate and multivariate Cox models were used to evaluate the association between hub genes and HCC diagnosis. Hub gene expression was experimentally validated in six HCC cell lines and 15 HCC samples using qRT-PCR and immunohistochemistry. The hub genes were uploaded to DSigDB for drug prediction enrichment analysis.ResultsWe identified that patients with abnormal miRNAs (hsa-miR-125b-5p and hsa-miR-21-5p) and their targeted genes (NTF3, PSMD14, CD320, and SORT1) had a worse prognosis. Methylation analysis of miRNA-targeted genes suggested that alteration of methylation levels is also a factor in the induction of tumorigenesis. We also found that the development of HCC progression caused by miRNA-mRNA interactions may be closely correlated with the infiltration of immunocytes. Moreover, the GSEA, GO, and KEGG analysis suggested that several common immune-related biological processes and pathways were related to miRNA-targeted genes. The results of qRT-PCR, immunohistochemistry, and western blotting were consistent with our bioinformatics results, suggesting that abnormal miRNAs and their targeted genes may affect HCC progression.ConclusionsBriefly, our study systematically describes the mechanisms of miRNA-mRNA interactions in HCC and predicts promising biomarkers that are associated with immune filtration for HCC progression.

LncRNA MIR17HG Suppresses Breast Cancer Proliferation and Migration as ceRNA to Target FAM135A by Sponging miR-454-3p

Breast cancer is one of the most common malignant tumors in women, and causes a large number of cancer-related deaths. The main cause of death of breast cancer patients is tumor recurrence and metastasis. Recent studies show that lncRNA (Long non-coding RNA) plays an important role in breast cancer. However, the overall biological activity and clinical consequences of the lncRNA MIR17HG in breast cancer remain unclear. Thus, we investigate how the MIR17HG/miR-454-3p network impacts breast cancer cell proliferation and migration. Given the TCGA and Oncomine databases, the researchers evaluated variations in MIR17HG expression for the survival rates of breast cancer patients. The influence of MIR17HG on cell proliferation, migration, cell cycle, and the mRNA expression level of miR-454-3p and FAM135A (family with sequence similarity 135 member A) is identified. Luciferase assay was used to detect the regulatory effect of miR-454-3p on the 3′UTR region of FAM135A, and rescue experiments demonstrated that MIR17HG can up-regulate FAM135A expression by competitively binding miR-454-3p. The effect of FAM135A on the cloning and invasion of MCF-7 cells was detected. MIR17HG expression is reduced in breast cancer tissues, and patients with greater levels of MIR17HG expression have a better prognosis. MIR17HG overexpression caused G2/M arrest in breast cancer cells according to a flow cytometry assay. FAM135A knockdown enhances breast cancer cell proliferation and clone creation, as well as two-dimensional and three-dimensional migratory capacities. Patients with high FAM135A expression in their breast cancer had a better prognosis. These novel findings indicate that MIR17HG may be a potential target for breast cancer. Our findings demonstrated that MIR17HG might suppress breast cancer cell proliferation and migration by sponge miR-454-3p through ceRNA(competing endogenous RNAs) mechanism, indicating that targeting MIR17HG may be a feasible therapeutic candidate for breast cancer.Graphical

Construction and validation of an angiogenesis-related lncRNA prognostic model in lung adenocarcinoma.

Background: There is increasing evidence that long non-coding RNAs (lncRNAs) can be used as potential prognostic factors for cancer. This study aimed to develop a prognostic model for lung adenocarcinoma (LUAD) using angiogenesis-related long non-coding RNAs (lncRNAs) as potential prognostic factors. Methods: Transcriptome data from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) were analyzed to identify aberrantly expressed angiogenesis-related lncRNAs in LUAD. A prognostic signature was constructed using differential expression analysis, overlap analysis, Pearson correlation analysis, and Cox regression analysis. The model's validity was assessed using K-M and ROC curves, and independent external validation was performed in the GSE30219 dataset. Prognostic lncRNA-microRNA (miRNA)-messenger RNA (mRNA) competing endogenous RNA (ceRNA) networks were identified. Immune cell infiltration and mutational characteristics were also analyzed. The expression of four human angiogenesis-associated lncRNAs was quantified using quantitative real-time PCR (qRT-PCR) gene arrays. Results: A total of 26 aberrantly expressed angiogenesis-related lncRNAs in LUAD were identified, and a Cox risk model based on LINC00857, RBPMS-AS1, SYNPR-AS1, and LINC00460 was constructed, which may be an independent prognostic predictor for LUAD. The low-risk group had a significant better prognosis and was associated with a higher abundance of resting immune cells and a lower expression of immune checkpoint molecules. Moreover, 105 ceRNA mechanisms were predicted based on the four prognostic lncRNAs. qRT-PCR results showed that LINC00857, SYNPR-AS1, and LINC00460 were significantly highly expressed in tumor tissues, while RBPMS-AS1 was highly expressed in paracancerous tissues. Conclusion: The four angiogenesis-related lncRNAs identified in this study could serve as a promising prognostic biomarker for LUAD patients.

The landscape of m1A modification and its posttranscriptional regulatory functions in primary neurons.

Cerebral ischaemia‒reperfusion injury (IRI), during which neurons undergo oxygen-glucose deprivation/reoxygenation (OGD/R), is a notable pathological process in many neurological diseases. N1-methyladenosine (m1A) is an RNA modification that can affect gene expression and RNA stability. The m1A landscape and potential functions of m1A modification in neurons remain poorly understood. We explored RNA (mRNA, lncRNA, and circRNA) m1A modification in normal and OGD/R-treated mouse neurons and the effect of m1A on diverse RNAs. We investigated the m1A landscape in primary neurons, identified m1A-modified RNAs, and found that OGD/R increased the number of m1A RNAs. m1A modification might also affect the regulatory mechanisms of noncoding RNAs, e.g., lncRNA-RNA binding proteins (RBPs) interactions and circRNA translation. We showed that m1A modification mediates the circRNA/lncRNA‒miRNA-mRNA competing endogenous RNA (ceRNA) mechanism and that 3' untranslated region (3'UTR) modification of mRNAs can hinder miRNA-mRNA binding. Three modification patterns were identified, and genes with different patterns had intrinsic mechanisms with potential m1A-regulatory specificity. Systematic analysis of the m1A landscape in normal and OGD/R neurons lays a critical foundation for understanding RNA modification and provides new perspectives and a theoretical basis for treating and developing drugs for OGD/R pathology-related diseases.

Identification of a novel circRNA–miRNA–mRNA regulatory axis in hepatocellular carcinoma based on bioinformatics analysis

In recent years, circular RNAs (circRNAs) have been found to play an essential regulatory role in hepatocellular carcinoma (HCC) through various mechanisms, particularly the endogenous competitive RNA (ceRNA) mechanism. Therefore, it is significant to explore the circRNAs in hepatoma. In this study, we constructed the ceRNA and survival network using Cytoscape. We also used R, Perl software, and multiple online databases and platforms, including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), to perform overall survival, immune cell infiltration, immune checkpoints, pathway activity, and anticancer drug sensitivity analysis of the genes. Finally, the receiver operator characteristic curve (ROC) analysis was performed to identify the diagnosis value of the genes. KEGG analysis revealed the T cell receptor signaling pathway as the main enrichment pathway. A total of 29 genes related to survival and prognosis were screened out. The findings suggest that ZNF544, WDR76, ACTG1, RASSF3, E2F3, ASRGL1, and POGK are associated with multilevel immune cell infiltration. Additionally, immune checkpoint analysis screened out the ACTG1, E2F3, RASSF3, and WDR76. It was also revealed that the WDR76, E2F3, ASRGL1, and POGK mainly activated the cell cycle and DNA damage response (DDR) pathway. The results suggest that the sensitivity toward trametinib, refametinib (RDEA119), and selumetinib correlates to the expression of WDR76. ROC analysis showed that the area under the curve (AUC) of all genes in the regulatory axis was greater than 0.7. The identified hsa_circ_0000417/hsa_circ_0002688/hsa_circ_0001387--hsa-miR-199a-5p--WDR76 regulatory axis may provide new insights into the progression, clinical diagnosis, and treatment of HCC.

DNA hypomethylation and upregulated LINC00518 acts as a promoter and biomarker in head and neck squamous cell carcinoma.

Background: LINC00518 acts as an oncogene in several cancers, but its function in head and neck squamous cell carcinoma (HNSCC) remains unclear. Materials & methods: The expression and methylation status of LINC00518 were analyzed by reviewing public databases. The ceRNA network and the relationship with tumor immunity of LINC00518 were analyzed using online tools and in vitro studies. Results: Upregulated LINC00518 was associated with poor clinicopathological characteristics of HNSCC. Silencing LINC00518 significantly inhibited the migration of HNSCC cells. LINC00518 might positively regulate HMGA2 via the ceRNA mechanism. Additionally, LINC00518 was negatively correlated with various immune cells and immunotherapy markers. Moreover, the upregulation of LINC00518 in HNSCC may be due to DNA hypomethylation. Conclusion: LINC00518 may be a potential biomarker and therapeutic target for HNSCC.

Proangiogenic role of circRNA-007371 in liver fibrosis.

Circular RNAs (circRNAs) are crucially involved in cancers as competing endogenous RNA (ceRNA) or microRNA (miRNA) sponges. However, the function and mechanism of circRNAs in liver fibrosis remain unknown and are the focus of this study. Murine fibrotic models were induced by thioacetamide (TAA) or carbon tetrachloride (CCl4 ). Increased angiogenesis is accompanied by liver fibrosis in TAA- and CCl4 -induced murine fibrotic livers. circRNA microarray and argonaute 2 (AGO2)-RNA immunoprecipitation (RIP) sequencing (AGO2-RIP sequencing) were performed in murine livers to screen for functional circRNAs. Compared to control livers, 86 differentially expressed circRNAs were obtained in TAA-induced murine fibrotic livers using circRNA microarray. In addition, 551 circRNAs were explored by AGO2-RIP sequencing of murine fibrotic livers. The circRNA-007371 was then selected and verified for back-spliced junction, resistance to RNase R, and loop formation. In vitro, murine hemangioendothelioma endothelial (EOMA) cells were transfected with circRNA-007371 overexpressing plasmid or empty plasmid. circRNA-007371 overexpression promoted tube formation, migration, and cell proliferation of EOMA cells. RNA sequencing and miRNA sequencing were then performed to explore the mechanism of the proangiogenic effects of circRNA-007371. circRNA-007371 promotes liver fibrosis via miRNA sponges or ceRNA mechanisms. Stag1, the parent gene of circRNA-007371, may play a significant role in proangiogenic progression. In conclusion, circRNA-007371 enhances angiogenesis via a miRNA sponge mechanism in liver fibrosis. The antiangiogenic effect of circRNA-007371 inhibition may provide a new strategy for treating patients with liver cirrhosis.

Circular RNA suppression of vascular smooth muscle apoptosis through the miR-545-3p/CKAP4 axis during abdominal aortic aneurysm formation.

Abdominal aortic aneurysms (AAA) are an important cause of cardiovascular deaths. The loss of vascular smooth muscle cells (VSMCs) has been reported to be related to the pathology of AAA. This study focused on investigating the function of circ_0002168 in VSMC apoptosis. Levels of genes and proteins were measured by quantitative real-time-polymerase chain reaction (qRT-PCR) and Western blot. The growth of VSMCs was determined by using cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry and the evaluation of caspase-3 activity analysis, reactive oxygen species (ROS) production as well as lactate dehydrogenase (LDH) activity. The binding between miR-545-3p and circ_0002168 or Cytoskeleton-associated protein 4 (CKAP4) was confirmed by bioinformatics analysis, dual-luciferase reporter, RNA immunoprecipitation, and pull-down assays. Circ_0002168 decreased in the aortic tissues of patients with AAA. Functionally, ectopic overexpression of circ_0002168 dramatically induced proliferation and suppressed apoptosis in VSMCs. Mechanistically, circ_0002168 sequestered miR-545-3p to release CKAP4 expression via the ceRNA mechanism, indicating the circ_0002168/miR-545-3p/CKAP4 feedback loop in VSMCs. Increased miR-545-3p and a decreased CKAP4 expression were observed in patients with AAA. Rescue experiments showed that miR-545-3p reversed the protective effects of circ_0002168 on VSMC proliferation. Moreover, inhibition of miR-545-3p could restrain the apoptosis of VSMCs, which was abolished by CKAP4 silencing. Circ_0002168 has a protective effect on VSMC proliferation by regulating the miR-545-3p/CKAP4 axis, adding further understanding of the pathogenesis of AAA and a potential therapeutic approach in AAA management.

Competing Endogenous RNA Regulatory Networks of hsa_circ_0126672 in Pathophysiology of Coronary Heart Disease.

Coronary heart disease (CHD) is a global health concern, and its molecular origin is not fully elucidated. Dysregulation of ncRNAs has been linked to many metabolic and infectious diseases. This study aimed to explore the role of circRNAs in the pathogenesis of CHD and predicted a candidate circRNA that could be targeted for therapeutic approaches to the disease. circRNAs associated with CHD were identified and CHD gene expression profiles were obtained, and analyzed with GEO2R. In addition, differentially expressed miRNA target genes (miR-DEGs) were identified and subjected to functional enrichment analysis. Networks of circRNA/miRNA/mRNA and the miRNA/affected pathways were constructed. Furthermore, a miRNA/mRNA homology study was performed. We identified that hsa_circ_0126672 was strongly associated with the CHD pathology by competing for endogenous RNA (ceRNA) mechanisms. hsa_circ_0126672 characteristically sponges miR-145-5p, miR-186-5p, miR-548c-3p, miR-7-5p, miR-495-3p, miR-203a-3p, and miR-21. Up-regulation of has_circ_0126672 affected various CHD-related cellular functions, such as atherosclerosis, JAK/STAT, and Apelin signaling pathways. Our results also revealed a perfect and stable interaction for the hybrid of miR-145-5p with NOS1 and RPS6KB1. Finally, miR-145-5p had the highest degree of interaction with the validated small molecules. Henchashsa_circ_0126672 and target miRNAs, notably miR-145-5p, could be good candidates for the diagnosis and therapeutic approaches to CHD.

Hsa_circ_0046430 promotes the progression of colorectal cancer by targeting miR-6785-5p/SRCIN1 axis as a ceRNA.

The correlation among circular RNAs (circRNAs), microRNAs, and messenger RNAs have gained increasing attention in recent years. However, the mechanism of such discoveries in colorectal cancer (CRC) is not yet elucidated. The present study aimed to clarify whether the novel circRNAs regulate the prognosis-related genes through the competing endogenous RNAs (ceRNA). An analysis of the Weighted Gene Co-Expression Network Analysis was conducted to screen a module-trait circRNAs, and other big data mining technologies were used to predict the related microRNAs and the downstream genes. Prognosis-related gene model was built using the Cox regression analysis for the 138 messenger RNAs associated with hsa circ 0046430. The qRT-PCR was adopted to verify ceRNA network. Immunohistochemistry verified the correlation between SRCIN1 and patient prognosis. In summary, these results demonstrated that hsa_circ_0046430 is a tumor-related circRNA based on the clinical characteristics module of Weighted Gene Co-Expression Network Analysis. The prognostic risk score signature model analysis indicated that CRC risk was independently related to the risk score and SRCIN1 was independently associated with overall survival. Therefore, the hsa_circ_0046430/miR-6785-5p/SRCIN1 axis was constructed. Hsa_circ_0046430/miR-6785-5p/SRCIN1 axis relative expression level was determined by qRT-PCR. Immunohistochemical staining further validated that SCRIN1 was significantly higher in cancer than in adjacent normal tissues. Our study identified and primarily validated the hsa_circ_0046430/miR-6785-5p/SRCIN1 regulatory axis impacted on CRC prognosis, suggesting novel biomarkers and therapeutic targets for CRC patients. Further in-depth studies are essential to confirm the underlying ceRNA mechanism.