Effects of silencing hsa_circ_0015326 on proliferation, migration, invasion, and apoptosis of epithelial ovarian cancer cells.

Although the treatment of ovarian cancer has made great progress, there are still many patients who are not timely detected and given targeted therapy due to unknown pathogenesis. Recent studies have found that hsa_circ_0015326 is upregulated in ovarian cancer and is involved in the proliferation, invasion, and migration of ovarian cancer cells. However, whether hsa_circ_0015326 can be used as a new target of ovarian cancer needs further investigation. Therefore, the effect of hsa_circ_0015326 on epithelial ovarian cancer was investigated in this study. At first, si-hsa_circ_0015326 lentivirus was transfected into epithelial ovarian cancer cells. Then real-time fluorescence quantitative PCR (qRT-PCR) was used to detect hsa_circ_0015326 level. The proliferation of ovarian cancer cells was detected by CCK-8 assay. The horizontal and vertical migration abilities of the cells were detected by wound-healing assay and Transwell assay, respectively. Transwell assay was also used to determine the invasion rate. As for the apoptosis rate, it was assessed by flow cytometry. As a result, the expression level of hsa_circ_0015326 in A2780 and SKOV3 was found to be higher than that in IOSE-80. However, after transfecting si-hsa_circ_0015326 and si-NC into the cells, the proliferation, migration, and invasion abilities of A2780 and SKOV3 cells in the si-hsa_circ_0015326 group were significantly reduced in comparison to those in the si-NC and mock groups, while their apoptosis rates were elevated. Collectively, silencing hsa_circ_0015326 bears the capability of inhibiting the proliferation, migration, and invasion of ovarian cancer cells while increasing apoptosis rate. It can be concluded that hsa_circ_0015326 promotes the malignant biological activities of epithelial ovarian cancer cells.

Mex-3 RNA binding family member A (MEX3A)/circMPP6 complex promotes colorectal cancer progression by inhibiting autophagy.

RNA-binding proteins (RBPs)-RNA networks have contributed to cancer development. Circular RNAs (circRNAs) are considered as protein recruiters; nevertheless, the patterns of circRNA-protein interactions in colorectal cancer (CRC) are still lacking. Processing bodies (PBs) formed through liquid-liquid phase separation (LLPS) are membrane-less organelles (MLOs) consisting of RBPs and RNA. Previous evidence suggests a connection between PBs dynamics and cancer progression. Despite the increasingly acknowledged crucial role of RBPs and RNA in the accumulation and maintenance of MLOs, there remains a lack of specific research on the interactions between PBs-related RBPs and circRNAs in CRC. Herein, we identify that MEX-3 RNA binding family member A (MEX3A), frequently upregulated in CRC tissues, predicts poorer patient survival. Elevated MEX3A accelerates malignance and inhibits autophagy of CRC cells. Importantly, MEX3A undergoes intrinsically disordered regions (IDRs)-dependent LLPS in the cytoplasm. Specifically, circMPP6 acts as a scaffold to facilitate the interaction between MEX3A and PBs proteins. The MEX3A/circMPP6 complex modulates PBs dynamic and promotes UPF-mediated phosphodiesterase 5A (PDE5A) mRNA degradation, consequently leading to the aggressive properties of CRC cells. Clinically, CRC patients exhibiting high MEX3A expression and low PDE5A expression have the poorest overall survival. Our findings reveal a collaboration between MEX3A and circMPP6 in the regulation of mRNA decay through triggering the PBs aggregation, which provides prognostic markers and/or therapeutic targets for CRC.

Utility of oligonucleotide in upregulating circular RNA production in a cellular model.

Circular RNAs (circRNAs), are a covalently closed, single-stranded RNA without 5'- and 3'-termini, commonly stem from the exons of precursor mRNAs (pre-mRNAs). They have recently garnered interest, with studies uncovering their pivotal roles in regulating various aspects of cell functions and disease progressions. A notable feature of circRNA lies in the mechanism of its biogenesis involving a specialized form of splicing: back-splicing. A splicing process that relies on interactions between introns flanking the circularizing exon to bring the up and downstream splice sites in proximity through the formation of a prerequisite hairpin structure, allowing the spliceosomes to join the two splice sites together to produce a circular RNA molecule. Based on this mechanism, we explored the feasibility of facilitating the formation of such a prerequisite hairpin structure by utilizing a newly designed oligonucleotide, CircuLarIzation Promoting OligoNucleotide (CLIP-ON), to promote the production of circRNA in cells. CLIP-ON was designed to hybridize with and physically bridge two distal sequences in the flanking introns of the circularizing exons. The feasibility of CLIP-ON was confirmed in HeLa cells using a model pre-mRNA, demonstrating the applicability of CLIP-ON as a trans-acting modulator to upregulate the production of circRNAs in a cellular environment.

Magnetic Graphene Oxide Nanocomposites Boosts Craniomaxillofacial Bone Regeneration by Modulating circAars/miR-128-3p/SMAD5 Signaling Axis.

Background: The ability of nanomaterials to induce osteogenic differentiation is limited, which seriously imped the repair of craniomaxillofacial bone defect. Magnetic graphene oxide (MGO) nanocomposites with the excellent physicochemical properties have great potential in bone tissue engineering. In this study, we aim to explore the craniomaxillofacial bone defect repairment effect of MGO nanocomposites and its underlying mechanism. Methods: The biocompatibility of MGO nanocomposites was verified by CCK8, live/dead staining and cytoskeleton staining. The function of MGO nanocomposites induced osteogenic differentiation of BMSCs was investigated by ALP activity detection, mineralized nodules staining, detection of osteogenic genes and proteins, and immune-histochemical staining. BMSCs with or without MGO osteogenic differentiation induction were collected and subjected to high-throughput circular ribonucleic acids (circRNAs) sequencing, and then crucial circRNA circAars was screened and identified. Bioinformatics analysis, Dual-luciferase reporter assay, RNA binding protein immunoprecipitation (RIP), fluorescence in situ hybridization (FISH) and osteogenic-related examinations were used to further explore the ability of circAars to participate in MGO nanocomposites regulation of osteogenic differentiation of BMSCs and its potential mechanism. Furthermore, critical-sized calvarial defects were constructed and were performed to verify the osteogenic differentiation induction effects and its potential mechanism induced by MGO nanocomposites. Results: We verify the good biocompatibility and osteogenic differentiation improvement effects of BMSCs mediated by MGO nanocomposites. Furthermore, a new circRNA-circAars, we find and identify, is obviously upregulated in BMSCs mediated by MGO nanocomposites. Silencing circAars could significantly decrease the osteogenic ability of MGO nanocomposites. The underlying mechanism involved circAars sponging miR-128-3p to regulate the expression of SMAD5, which played an important role in the repair craniomaxillofacial bone defects mediated by MGO nanocomposites. Conclusion: We found that MGO nanocomposites regulated osteogenic differentiation of BMSCs via the circAars/miR-128-3p/SMAD5 pathway, which provided a feasible and effective strategy for the treatment of craniomaxillofacial bone defects.

CircSNX6 promotes proliferation, metastasis, and angiogenesis in hepatocellular carcinoma via miR-383-5p/VEGFA signaling pathway.

The role of circular RNA (circRNAs) in hepatocellular carcinoma (HCC) has been extensively studied. Previous research has highlighted the regulatory role of circSNX6 in HCC cells and tissues. However, the precise mechanism underlying HCC progression still requires comprehensive investigation. The study initially utilized quantitative reverse transcription-polymerase chain reaction (qRT-PCR) to assess circSNX6 expression levels in HCC cell lines and tissues. Subsequently, the stability of circRNA was evaluated through Ribonuclease R and actinomycin D treatment assays. The impact of circSNX6 knockdown on proliferation, migration, invasion, and angiogenesis abilities was determined using various assays including colony formation, Transwell culture system, tube formation assay, and cell counting kit (CCK)-8 assays. Additionally, RNA immunoprecipitation chip and dual-luciferase reporter assays were employed to investigate the interactions between circSNX6 and miR-383-5p. Finally, an HCC xenograft tumor model in mice was established to assess the in vivo expression of circSNX6 and its functional role in HCC. Our findings revealed an elevated circSNX6 expression in HCC tissues, which was correlated with poor patient prognosis. Knockdown of circSNX6 suppressed HCC cell growth, invasion, metastasis, and angiogenesis. The downregulation of miR-383-5p, a target of circSNX6, significantly attenuated the tumor-suppressive effects induced by circSNX6 knockdown. Moreover, circSNX6 was found to modulate VEGFA expression by targeting miR-383-5p. The inhibition of HCC cell proliferation by miR-383-5p could be partially reversed by overexpressing VEGFA. Silencing circSNX6 also suppressed tumor formation and the metastasis of HCC cells in a mouse model. In summary, our findings suggest that circSNX6 promotes cell proliferation, metastasis, and angiogenesis in HCC by regulating the miR-383-5p/VEGFA pathway.

Role of Hsa_circ_0000880 in the Regulation of High Glucose-Induced Apoptosis of Retinal Microvascular Endothelial Cells.

Purpose: Circular RNAs (circRNAs) have been verified to participate in multiple biological processes and disease progression. Yet, the role of circRNAs in the pathogenesis of diabetic retinopathy (DR) is still poorly understood and deserves further study. This study aimed to investigate the role of circRNAs in the regulation of high glucose (HG)-induced apoptosis of retinal microvascular endothelial cells (RMECs). Methods: Epiretinal membranes from patients with DR and nondiabetic patients with idiopathic macular epiretinal membrane were collected for this study. The circRNA microarrays were performed using high-throughput sequencing. Hierarchical clustering, functional enrichment, and network regulation analyses were used to analyze the data generated by high-throughput sequencing. Next, RMECs were subjected to HG (25 mM) conditions to induce RMECs apoptosis in vitro. A series of experiments, such as Transwell, the Scratch wound, and tube formation, were conducted to explore the regulatory effect of circRNA on RMECs. Fluorescence in situ hybridization (FISH), immunofluorescence staining, and Western blot were used to study the mechanism underlying circRNA-mediated regulation. Results: A total of 53 differentially expressed circRNAs were found in patients with DR. Among these, hsa_circ_0000880 was significantly upregulated in both the diabetic epiretinal membranes and in an in vitro DR model of HG-treated RMECs. Hsa_circ_0000880 knockout facilitated RMECs vitality and decreased the paracellular permeability of RMECs under hyperglycemia. More importantly, silencing of hsa_circ_0000880 significantly inhibited HG-induced ROS production and RMECs apoptosis. Hsa_circ_0000880 acted as an endogenous sponge for eukaryotic initiation factor 4A-III (EIF4A3). Knockout of hsa_circ_0000880 reversed HG-induced decrease in EIF4A3 protein level. Conclusions: Our findings suggest that hsa_circ_0000880 is a novel circRNA can induce RMECs apoptosis in response to HG conditions by sponging EIF4A3, offering an innovative treatment approach against DR. Translational Relevance: The circRNAs participate in the dysregulation of microvascular endothelial function induced by HG conditions, indicating a promising therapeutic target for DR.

Circular RNA-GRIN2B Suppresses Neuropathic Pain by Targeting the NF-κB/SLICK Pathway.

The role of circular RNAs (circRNAs) in neuropathic pain is linked to the fundamental physiological mechanisms involved. However, the exact function of circRNAs in the context of neuropathic pain is still not fully understood. The functional impact of circGRIN2B on the excitability of dorsal root ganglion (DRG) neurons was investigated using siRNA or overexpression technology in conjunction with fluorescence in situ hybridization and whole-cell patch-clamp technology. The therapeutic efficacy of circGRIN2B in treating neuropathic pain was confirmed by assessing the pain threshold in a chronic constrictive injury (CCI) model. The interaction between circGRIN2B and NF-κB was examined through RNA pulldown, RIP, and mass spectrometry assays. CircGRIN2B knockdown significantly affected the action potential discharge frequency and the sodium-dependent potassium current flux (SLICK) in DRG neurons. Furthermore, knockdown of circGRIN2B dramatically reduced the SLICK channel protein and mRNA expression in vivo and in vitro. Our research confirmed the interaction between circGRIN2B and NF-κB. These findings demonstrated that circGRIN2B promotes the transcription of the SLICK gene by binding to NF-κB. In CCI rat models, the overexpression of circGRIN2B has been shown to hinder the progression of neuropathic pain, particularly by reducing mechanical and thermal hyperalgesia. Additionally, this upregulation significantly diminished the levels of the inflammatory cytokines IL-1ß, IL-6, and TNF-α in the DRG. Upon reviewing these findings, it was determined that circGRIN2B may mitigate the onset of neuropathic pain by modulating the NF-κB/SLICK pathway.

Comprehensive analysis of circRNA expression profiles in postmenopausal women differing in bone mineral density.

Postmenopausal osteoporosis (PMOP) seriously endangers the bone health of older women. Although there are currently indicators to diagnose PMOP, early diagnostic biomarkers are lacking. Circular ribonucleic acid (circRNA) has a stable structure, regulates gene expression, participates in the pathological process of disease, and has the potential to become a biomarker. The purpose of this study was to investigate circRNAs that could be used to predict patients with early PMOP. Ribonucleic acid (RNA) sequencing was performed on peripheral blood leukocytes from 15 female patients to identify differential circRNAs between different groups. Using bioinformatics analysis, enrichment analysis was performed to discover relevant functions and pathways. CircRNA-micro ribonucleic acid (miRNA) interaction analysis and messenger ribonucleic acid (mRNA) prediction and network construction help us to understand the relationship between circRNA, miRNA, and mRNA. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate the gene expression of candidate circRNAs. We screened out 2 co-expressed differential circRNAs, namely hsa_circ_0060849 and hsa_circ_0001394. By analyzing the regulatory network, a total of 54 miRNAs and 57 osteoporosis-related mRNAs were identified, which, as potential downstream target genes of hsa_circ_0060849 and hsa_circ_0001394, may play a key role in the occurrence and development of PMOP. The occurrence and development of PMOP is regulated by circRNAs, and hsa_circ_0060849 and hsa_circ_0001394 can be used as new diagnostic markers and therapeutic targets for early PMOP.

N6-methyladenosine-modified circSLCO1B3 promotes intrahepatic cholangiocarcinoma progression via regulating HOXC8 and PD-L1.

BACKGROUND: Refractoriness to surgical resection and chemotherapy makes intrahepatic cholangiocarcinoma (ICC) a fatal cancer of the digestive system with high mortality and poor prognosis. Important function invests circRNAs with tremendous potential in biomarkers and therapeutic targets. Nevertheless, it is still unknown how circRNAs contribute to the evolution of ICC. METHODS: CircRNAs in paired ICC and adjacent tissues were screened by circRNAs sequencing. To explore the impact of circRNAs on ICC development, experiments involving gain and loss of function were conducted. Various experimental techniques, including quantitative real-time PCR (qPCR), western blotting, RNA immunoprecipitation (RIP), luciferase reporter assays, RNA pull-down, chromatin immunoprecipitation (ChIP), ubiquitination assays and so on were employed to identify the molecular regulatory role of circRNAs. RESULTS: Herein, we reported a new circRNA, which originates from exon 9 to exon 15 of the SLCO1B3 gene (named circSLCO1B3), orchestrated ICC progression by promoting tumor proliferation, metastasis and immune evasion. We found that the circSLCO1B3 gene was highly overexpressed in ICC tissues and related to lymphatic metastasis, tumor sizes, and tumor differentiation. Mechanically, circSLCO1B3 not only promoted ICC proliferation and metastasis via miR-502-5p/HOXC8/SMAD3 axis, but also eradicated anti-tumor immunity via suppressing ubiquitin-proteasome-dependent degradation of PD-L1 by E3 ubiquitin ligase SPOP. We further found that methyltransferase like 3 (METTL3) mediated the m6A methylation of circSLCO1B3 and stabilizes its expression. Our findings indicate that circSLCO1B3 is a potential prognostic marker and therapeutic target in ICC patients. CONCLUSIONS: Taken together, m6A-modified circSLCO1B3 was correlated with poor prognosis in ICC and promoted ICC progression not only by enhancing proliferation and metastasis via potentiating HOXC8 expression, but also by inducing immune evasion via antagonizing PD-L1 degradation. These results suggest that circSLCO1B3 is a potential prognostic marker and therapeutic target for ICC.

Statins improve cardiac endothelial function to prevent heart failure with preserved ejection fraction through upregulating circRNA-RBCK1.

Heart failure with preserved ejection fraction (HFpEF) is associated with endothelial dysfunction. We have previously reported that statins prevent endothelial dysfunction through inhibition of microRNA-133a (miR-133a). This study is to investigate the effects and the underlying mechanisms of statins on HFpEF. Here, we show that statins upregulate the expression of a circular RNA (circRNA-RBCK1) which is co-transcripted with the ring-B-box-coiled-coil protein interacting with protein kinase C-1 (RBCK1) gene. Simultaneously, statins increase activator protein 2 alpha (AP-2α) transcriptional activity and the interaction between circRNA-RBCK1 and miR-133a. Furthermore, AP-2α directly interacts with RBCK1 gene promoter in endothelial cells. In vivo, lovastatin improves diastolic function in male mice under HFpEF, which is abolished by loss function of endothelial AP-2α or circRNA-RBCK1. This study suggests that statins upregulate the AP-2α/circRNA-RBCK1 signaling to suppress miR-133a in cardiac endothelial cells and prevent diastolic dysfunction in HFpEF.

Construction and analysis of competitive endogenous RNA networks and prognostic models associated with ovarian cancer based on the exoRBase database.

OBJECTIVE: To construct a competitive endogenous RNA (ceRNA) regulatory network in blood exosomes of patients with ovarian cancer (OC) using bioinformatics and explore its pathogenesis. METHODS: The exoRbase2.0 database was used to download blood exosome gene sequencing data from patients OC and normal controls and the expression profiles of exosomal mRNA, long non-coding RNA (lncRNA), and circular RNA (circRNA) were detected independently using R language for differential expression analysis. TargetScan and miRanda databases were combined for the prediction and differential expression of mRNA-binding microRNAs (miRNA). The miRcode and starBase databases were used to predict miRNAs that bind to differentially expressed lncRNAs and circRNAs repectively. The relevant mRNA, circRNA, lncRNA and their corresponding miRNA prediction data were imported into Cytoscape software for visualization of the ceRNA network. The R language and KEGG Orthology-based Annotation System (KOBAS) were used to execute and illustrate the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Hub genes were identified using The CytoHubba plugin. RESULTS: Thirty-one differentially expressed mRNAs, 17 differentially expressed lncRNAs, and 24 differentially expressed circRNAs were screened. Cytoscape software was used to construct the ceRNA network with nine mRNA nodes, two lncRNA nodes, eight circRNA nodes, and 51 miRNA nodes. Both GO and KEGG were focused on the Spliceosome pathway, indicating that spliceosomes are closely linked with the development of OC, while heterogenous nuclear ribonucleoprotein K and RNA binding motif protein X-linked genes were the top 10 score Hub genes screened by Cytoscape software, including two lncRNAs, four mRNAs, and four circRNAs. In patients with OC, the expression of eukaryotic translation initiation factor 4 gamma 2 (EIF4G2), SERPINE 1 mRNA binding protein 1 (SERBP1), ribosomal protein L15 (RPL15) and human leukocyte antigen complex P5 (HCP5) was significantly higher whereas that of testis expressed transcript, Y-linked 15 and DEAD-box helicase 3 Y-linked genes was lower compared to normal controls Immunocorrelation scores revealed that SERBP1 was significantly and negatively correlated with endothelial cells and CD4+ T cells and positively correlated with natural killer (NK) cells and macrophages, respectively; RPL15 was significantly positively correlated with macrophages and endothelial cells and negatively correlated with CD8+ T cells and uncharacterized cells, respectively. EIF4G2 was significantly and negatively correlated with endothelial cells and CD4+ T cells, and positively correlated with uncharacterized cells, respectively. Based on the survival data and the significant correlation characteristics derived from the multifactorial Cox analysis (P < 0.05), the survival prediction curves demonstrated that the prognostic factors associated with 3-year survival in patients with OC were The prognostic factors associated with survival were Macrophage, RPL15. CONCLUSION: This study successfully constructs a ceRNA regulatory network in blood exosomes of OV patients, which provides the specific targets for diagnosis and treatment of OC.

CircBCL2L13 attenuates cardiomyocyte oxidative stress and apoptosis in cardiac ischemia‒reperfusion injury via miR-1246/PEG3 signaling.

Ischemia‒reperfusion (I/R) is a common complication in the clinical treatment of acute myocardial infarction (MI), in which cardiomyocytes play a pivotal role in the recovery of cardiac function after reperfusion injury. The expression of numerous circular ribonucleic acids (circRNAs) is disrupted in I/R-induced cardiac damage, but the potential role of circRNAs in I/R damage has not been fully elucidated. The purpose of the present study was to clarify the biological action and molecular mechanism of circRNA 002166 (also termed circCL2L13) in postmyocardial I/R. Oxygen-glucose deprivation/reoxygenation (OGD/R) in an in vivo model was performed to simulate I/R damage. real-time polymerase chain reaction analysis was also conducted to evaluate the relationships of the SOD1, SOD2, NRF2, HO1 and GPX4 indicators with oxidative stress injury. TUNEL immunofluorescence was used to evaluate the degree of cardiomyocyte apoptosis in the different treatment groups. The circBCL2L13 level was markedly upregulated in myocardial tissues from a mouse I/R model. Overexpression of circBCL2L13 markedly attenuated the expression of oxidative stress-related genes and apoptosis in OGD/R-induced cardiomyocytes. A mechanistic study revealed that circBCL2L13 functions as a ceRNA for miR-1246 and modulates paternally expressed gene 3 (PEG3). Eventually, circBCL2L13 was proven to regulate PEG3 by targeting miR-1246, thereby protecting against OGD/R-induced cardiomyocyte oxidative damage and apoptosis. In conclusion, our study confirmed that the circBCL2L13/miR-1246/PEG3 axis suppressed the progression of OGD/R injury in cardiomyocytes, which might lead to new therapeutic strategies for cardiac I/R injury.

Circular RNAs: Biogenesis, Functions, and Role in Myocardial Hypertrophy.

Circular RNAs (circRNAs) are a large class of endogenous single-stranded covalently closed RNA molecules. High-throughput RNA sequencing and bioinformatic algorithms have identified thousands of eukaryotic circRNAs characterized by high stability and tissue-specific expression pattern. Recent studies have shown that circRNAs play an important role in the regulation of physiological processes in the norm and in various diseases, including cardiovascular disorders. The review presents current concepts of circRNA biogenesis, structural features, and biological functions, describes the methods of circRNA analysis, and summarizes the results of studies on the role of circRNAs in the pathogenesis of hypertrophic cardiomyopathy, the most common inherited heart disease.

CircNRD1 elevates THAP domain containing 11 through sequestering microRNA-421 to inhibit gastric cancer growth and tumorigenesis.

We explored the role and mechanism of circular RNAcircNRD1 in gastric cancer (GC) progression, aiming to identify new bio-markers for the treatment and prognosis of GC patients. The RNA expression was examined by reverse transcription-quantitative polymerase chain reaction. Cell proliferation, migration and invasion were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay, scratch assay and transwell assay. Western blot assay was conducted for protein expression measurement. Dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assays were conducted to verify the interaction between microRNA-421 (miR-421) and circNRD1 or THAP domain containing 11 (THAP11). Xenograft tumor model was established to perform in vivo experiments. CircNRD1 was notably downregulated in GC tissues and cell lines. Additionally, decreased circNRD1 level was closely associated with advanced tumor stage and dismal prognosis in GC patients. CircNRD1 overexpression suppressed the proliferation and metastasis of GC cells. CircNRD1 acted as a molecular sponge for miR-421 in GC cells, and the antitumor impacts of circNRD1 overexpression in GC cells could be alleviated by miR-421 overexpression. miR-421 directly targeted THAP11, and circNRD1 could up-regulate THAP11 expression in GC cells through sponging miR-421. THAP11 knockdown reversed circNRD1 overexpression-induced tumor suppressing effects in GC cells. CircNRD1 overexpression significantly blocked tumor growth in vivo. CircNRD1 suppressed the proliferation and metastasis of GC cells in vitro and blocked tumor growth in vivo via modulating miR-421/THAP11 axis.

CircGPC3 promotes hepatocellular carcinoma progression and metastasis by sponging miR-578 and regulating RAB7A/PSME3 expression.

CircRNAs are a class of highly stable noncoding RNAs that play an important role in the progression of many diseases, especially cancer. In this study, high-throughput sequencing was used to screen for abnormally expressed circRNAs, and we found that circGPC3 was overexpressed in HCC tissues. However, the underlying mechanism of circGPC3 in the development and metastasis of hepatocellular carcinoma (HCC) remains unknown. In our study, we found that circGPC3 was significantly upregulated in HCC tissues and cells and that its overexpression was positively correlated with overall survival, TNM stage and lymph node metastasis. In vivo and in vitro experiments showed that circGPC3 knockdown repressed HCC cell migration, invasion and proliferation and promoted apoptosis. Mechanistically, circGPC3 promoted HCC proliferation and metastasis through the miR-578/RAB7A/PSME3 axis. Our results demonstrate that circGPC3 contributes to the progression of HCC and provides an intervention target for HCC.

Mining key circRNA-associated-ceRNA networks for milk fat metabolism in cows with varying milk fat percentages.

BACKGROUND: Cow milk fat is an essential indicator for evaluating and measuring milk quality and cow performance. Growing research has identified the molecular functions of circular RNAs (circRNAs) necessary for mammary gland development and lactation in mammals. METHOD: The present study analyzed circRNA expression profiling data in mammary epithelial cells (MECs) from cows with highly variable milk fat percentage (MFP) using differential expression analysis and weighted gene co-expression network analysis (WGCNA). RESULTS: A total of 309 differentially expressed circRNAs (DE-circRNAs) were identified in the high and low MFP groups. WGCNA analysis revealed that the pink module was significantly associated with MFP (r = - 0.85, P = 0.007). Parental genes of circRNAs in this module were enriched mainly in lipid metabolism-related signaling pathways, such as focal adhesion, ECM-receptor interaction, adherens junction and AMPK. Finally, six DE-circRNAs were screened from the pink module: circ_0010571, circ_0007797, circ_0002746, circ_0003052, circ_0004319, and circ_0012840. Among them, circ_0002746, circ_0003052, circ_0004319, and circ_0012840 had circular structures and were highly expressed in mammary tissues. Subcellular localization revealed that these four DE-circRNAs may play a regulatory role in the mammary glands of dairy cows, mainly as competitive endogenous RNAs (ceRNAs). Seven hub target genes (GNB1, GNG2, PLCB1, PLCG1, ATP6V0C, NDUFS4, and PIGH) were obtained by constructing the regulatory network of their ceRNAs and then analyzed by CytoHubba and MCODE plugins in Cytoscape. Functional enrichment analysis revealed that these genes are crucial and most probable ceRNA regulators in milk fat metabolism. CONCLUSIONS: Our study identified several vital circRNAs and ceRNAs affecting milk fat synthesis, providing new research ideas and a theoretical basis for cow lactation, milk quality, and breed improvement.

CircROR1 upregulates CCNE1 expression to promote melanoma invasion and metastasis by recruiting KAT2A.

Circular RNAs (circRNAs) play important roles in cancer occurrence and progression. To explore and elucidate the clinical significance of specific circular RNA in melanoma and its potential molecular mechanism. CircROR1 expression in melanoma cells and tissues was confirmed by qRT-PCR and ISH. qRT-PCR and Western blotting were performed to measure the levels of CCNE1, KAT2A, MMP9 and TIMP2. MTT, Transwell and wound healing assays were performed to evaluate cell proliferation, invasion and metastasis. A xenograft mouse model was established to further verify the CircROR1/CCNE1 axis in vivo. RNA pull-down and RIP assays were performed to detect the direct interaction KAT2A and CircROR1. A ChIP assay was used to investigate the enrichment of H3K9ac acetylation in the CCNE1 promoter. CircROR1 was significantly upregulated in metastatic melanoma cells and tissues, promoting proliferation, invasion and metastasis in vitro and tumour growth in vivo. CircROR1 overexpression increased CCNE1 and MMP9 protein expression and decreased TIMP2 protein expression. Functional rescue assays demonstrated that CircROR1 played a role in promoting malignant progression through CCNE1. CircROR1 specifically bound to the KAT2A protein without affecting its expression. CircROR1 overexpression increased the level of H3K9ac modification in the CCNE1 promoter region by recruiting KAT2A, thus upregulating CCNE1 expression. CircROR1 upregulates CCNE1 expression through KAT2A-mediated histone acetylation. Our research confirms the critical role of CircROR1 in melanoma invasion and metastasis, and CircROR1 could serve as a potential therapeutic target for melanoma treatment.

Role of exosomal circular RNAs as microRNA sponges and potential targeting for suppressing hepatocellular carcinoma growth and progression.

In this editorial, we comment on the article by Lyu et al published in the recent issue of the World Journal of Gastroenterology (2023; 2219-2840). Hepatocellular carcinoma (HCC) is a frequently encountered and highly aggressive primary liver cancer, which remains the third-commonest cause of cancer-related death despite the current therapeutic modalities. There is urgency in developing novel therapeutic approaches, such as by manipulating extracellular vesicles, which constitute a highly heterogeneous nanoparticle population that contains various cargoes. These cargoes have a pivotal role in cell-to-cell communication and can modify the functional level of the recipient cells via their uptake by other recipient cells. Exosomal non-coding RNAs have particular evolving significance in HCC, such as circular RNAs, which have been found differentially expressed in normal hepatic and HCC tissues. The aberrations in their expression levels have a key role in the HCC development and progression and the overall prognosis. In this editorial, we will shed light on the emerging role of exosomal circular RNAs in HCC development and progression, focusing on the oncogenic or potentially tumor suppressive effect of mesenchymal stem cells-derived exosomal non-coding RNAs.

circRNA_8521 promotes Senecavirus A infection by sponging miRNA-324 to regulate LC3A.

Senecavirus A (SVA) causes outbreaks of vesicular disease in pigs, which imposes a considerable economic burden on the pork industry. As current SVA prevention measures are ineffective, new strategies for controlling SVA are urgently needed. Circular (circ)RNA is a newly characterized class of widely expressed, endogenous regulatory RNAs, which have been implicated in viral infection; however, whether circRNAs regulate SVA infection remains unknown. To investigate the influence of circRNAs on SVA infection in porcine kidney 15 (PK-15) cells, RNA sequencing technology was used to analyze the circRNA expression profiles of SVA-infected and uninfected PK-15 cells, the interactions between circRNAs, miRNAs, and mRNAs potentially implicated in SVA infection were predicted using bioinformatics tools. The prediction accuracy was verified using quantitative real-time (qRT)-PCR, Western blotting, as well as dual-luciferase reporter and RNA pull-down assays. The results showed that 67 circRNAs were differentially expressed as a result of SVA infection. We found that circ_8521 was significantly upregulated in SVA-infected PK-15 cells and promoted SVA infection. circ_8521 interacted with miR-324. miR-324 bound to LC3A mRNA which inhibited the expression of LC3A. Knockdown of LC3A inhibited SVA infection. However, circ_8521 promoted the expression of LC3A by binding to miR-324, thereby promoting SVA infection. We demonstrated that circ_8521 functioned as an endogenous miR-324 sponge to sequester miR-324, which promoted LC3A expression and ultimately SVA infection.