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Circular RNAs (circRNAs) are non‑coding RNAs that are found in the cytoplasm or stored in the exosomes, where they are not affected by RNA exonucleases. CircRNAs are widely expressed in mammalian tissues and cells. A number of studies have suggested that circRNAs are associated with the physiology and pathology of cardiovascular diseases (CVDs). Therefore, circRNAs have been considered as effector molecules and biomarkers in the cardiovascular system. The present review article summarizes the biological origin and roles of circRNAs as well as the available databases and research methods for their identification. Furthermore, it describes their regulatory mechanisms in cardiovascular physiology and pathology, including the regulation of atherosclerosis, immunity, cell proliferation, apoptosis and autophagy. In addition, the current review discusses the unresolved problems in circRNA research and the application of circRNAs in the treatment of CVDs. Finally, the CVD‑associated circRNAs are also reviewed.

Vascular smooth muscle cell (VSMC) proliferation is the pathological base of vascular remodelling diseases. Circular RNAs (circRNAs) are important regulators involved in various biological processes. However, the function of circRNAs in VSMC proliferation regulation remains largely unknown. This study was conducted to identify the key differentially expressed circRNAs (DEcircRNAs) and predict their functions in human aortic smooth muscle cell (HASMC) proliferation. To achieve this, DEcircRNAs between proliferative and quiescent HASMCs were detected using a microarray, followed by quantitative real-time RT-PCR validation. A DEcircRNA-miRNA-DEmRNA network was constructed, and functional annotation was performed using Gene Ontology (GO) and KEGG pathway analysis. The function of hsa_circ_0002579 in HASMC proliferation was analysed by Western blot. The functional annotation of the DEcircRNA-miRNA-DEmRNA network indicated that the four DEcircRNAs might play roles in the TGF-β receptor signalling pathway, Ras signalling pathway, AMPK signalling pathway and Wnt signalling pathway. Twenty-seven DEcircRNAs with coding potential were screened. Hsa_circ_0002579 might be a pro-proliferation factor of HASMC. Overall, our study identified the key DEcircRNAs between proliferative and quiescent HASMCs, which might provide new important clues for exploring the functions of circRNAs in vascular remodelling diseases., (© 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Ltd.)

Background: 5-fluorouracil (5-FU) is a widely used drug for cancer treatment, but its effect and underlying mechanisms on osteosarcoma (OS) cells remain unclear., Methods: U2OS and MG63 cells were treated with 0, 50, 100, and 500 μM 5-FU. MTS and flow cytometry were used to examine the effect of 5-FU on cell viability and apoptosis, respectively. Circular RNA (circRNA) expression was detected using RNA sequencing and quantitative real-time PCR (qPCR). Differentially expressed circRNAs were further subjected to the Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analysis to predict their functions. A circRNA-miRNA-mRNA interaction network was generated to analyze the regulatory networks of 5-FU-induced differentially expressed circRNAs. Western blotting (WB) was used to verify the protein in the downstream of circRNAs., Results: 5-FU inhibited the cell viability of the MG63 cells in a concentration-dependent manner. The most significant effect was observed in the cells treated with 500 μM 5-FU. Apoptosis was also increased in the MG63 cells after 500 μM 5-FU treatment for 3 days. RNA sequencing results showed that 183 differentially expressed circRNAs (172 upregulated and 11 downregulated) in 5-FU-treated cells. KEGG and GO analysis showed that the differentially expressed circRNAs were primarily enriched in proliferation-, apoptosis-, and metabolism-related functions. qPCR was used to verify the most upregulated and downregulated circRNAs. The circRNA-miRNA-mRNA interaction network showed that these 8 circRNAs had a sizable regulatory network that links a series of genes involved in tumor suppression., Conclusion: 5-FU treatment resulted in the differentially expressed circRNAs that were proliferation- and apoptosis-associated and were involved in the 5-FU-induced inhibition of tumor proliferation in OS cells.

Circular RNAs (circRNAs) play critical roles in the occurrence of human diseases, including cancer. However, the detailed functions of circRNAs in melanoma have not been fully elucidated. In the present study, a circRNA microarray was performed to analyze the variability of circRNAs in the low-metastatic melanoma WM35 cell line and in the high-metastatic melanoma WM451 cell line in comparison to control human melanocytes. The results revealed that five circRNAs were upregulated and four circRNAs were downregulated in both the WM35 and WM451 cells. qRT-PCR revealed an upregulated expression of circ0000082 and circ0016418 and a downregulation of circ0023988, circ0008157 and circ0030388 in the cells which was consistent with the results of the microarray assay. Functional tests revealed that knockdown of circ0023988, circ0008157 or circ0030388 significantly promoted the proliferation and invasion of the WM35 cells. Following the silencing of circ0000082 or circ0016418 in WM451 cells, the proliferation and invasion of the WM451 cells were inhibited. Bioinformatic analysis predicted that the circ0000082-, circ0023988- and circ0008157-circRNA-miRNA-mRNA network may participate in the occurrence, development, invasion and metastasis of malignant tumors. The present study revealed several differentially expressed circRNAs, indicating that the newly identified circRNAs may provide new therapeutic targets for melanoma.

Background: Papillary thyroid cancer (PTC) is the most common thyroid tumor (TC). However, there is still a lack of effective indicators for PTC detection and prognosis. We intended to find a novel tumor marker for the progression of PTC., Methods: The expression of circRNAs was measured by quantitative real-time polymerase chain reaction (qRT-PCR). SiRNA transfection was used to knockdown the expression of hsa&#95;circ&#95;0010023 in K1 cells. Cell proliferation was evaluated using cell counting and CCK8. Cell apoptosis was analyzed using flow cytometry. Hsa&#95;circ&#95;0010023 downstream pathways were predicted with bio-informatics analysis. The miR-1250-5p and MAPK1 were measured by qRT-PCR. The interaction between miR-1250-5p and hsa&#95;circ&#95;0010023 was vertified by dual-luciferase reporter assay., Results: Among the four circRNAs screened, only hsa&#95;circ&#95;0010023 and hsa&#95;circ&#95;0128482 were highly expressed in PTC (P < 0.05). The expression of hsa&#95;circ&#95;0010023 was significantly correlated with lymph node metastasis and extrathyroid infiltration (P < 0.05). Compared with the control group, the cell proliferation of the si-circ-0010023 group was significantly inhibited (P < 0.05). Knockdown of hsa&#95;circ&#95;0010023 promotes apoptosis of K1 cells (P < 0.001). The expression of hsa&#95;circ&#95;0010023 was negatively correlated with miR-1250-5p and positively correlated with MAPK1. MiR-1250-5p overexpression significantly reduced the luciferase activity of wild type plasmid (hsa&#95;circ&#95;0010023 WT), but not that of mutant type plasmid (hsa&#95;circ&#95;0010023 MUT)., Conclusion: The expression level of hsa&#95;circ&#95;0010023 was positive related to the progression of PTC, and hsa&#95;circ&#95;0010023 may promote PTC through sponging miR-1250-5p. Hsa&#95;circ&#95;0010023 may be a potential bio-marker for the diagnosis of PTC., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Glioma, a formidable form of brain cancer, poses significant challenges in terms of treatment and prognosis. Circular RNA nucleoporin 98 (circNUP98) has emerged as a potential regulator in various cancers, yet its role in glioma remains unclear. Here, we elucidate the functional role of circNUP98 in glioma cell proliferation, invasion, and migration, shedding light on its therapeutic implications. Glioma cells were subjected to si-NUP98 transfection, followed by assessments of cell viability, proliferation, invasion, and migration. Subcellular localization of circNUP98 was determined, and its downstream targets were identified. We delineated the binding relationships between circNUP98 and microRNA (miR)-520f-3p, as well as between miR-520f-3p and ETS transcription factor ELK4 (ELK4). The expression levels of circNUP98/miR-520f-3p/ELK4 were quantified. Our findings demonstrated that circNUP98 was upregulated in glioma cells, and its inhibition significantly attenuated glioma cell proliferation, invasion, and migration. Mechanistically, circNUP98 functioned as a sponge for miR-520f-3p, thereby relieving the inhibitory effect of miR-520f-3p on ELK4. Moreover, inhibition of miR-520f-3p or overexpression of ELK4 partially rescued the suppressive effect of circNUP98 knockdown on glioma cell behaviors. In summary, our study unveils that circNUP98 promotes glioma cell progression via the miR-520f-3p/ELK4 axis, offering novel insights into the therapeutic targeting of circNUP98 in glioma treatment., (© 2024 International Society for Developmental Neuroscience.)

Aberrant expression of circular RNAs (circRNAs) is frequently linked to colorectal cancer (CRC). Here, we identified circZFR as a promising biomarker for CRC diagnosis and prognosis. CircZFR was upregulated in CRC tissues and serum exosomes and its level was linked to cancer incidence, advanced-stages, and metastasis. In both in vitro and in vivo settings, circZFR promoted the growth and spread while suppressing apoptosis of CRC. Exosomes with circZFR overexpression promoted the proliferation and migration of cocultured CRC cells. Mechanistically, epithelial splicing regulatory protein 1 (ESRP1) in CRC cells may enhance the production of circZFR. BCL2-associated transcription factor 1 (BCLAF1) bound to circZFR, which prevented its ubiquitinated degradation. Additionally, circZFR sponged miR-3127-5p to boost rhotekin 2 (RTKN2) expression. Our TCP1-CD-QDs nanocarrier was able to carry and deliver circZFR siRNA (si-circZFR) to the vasculature of CRC tissues and cells, which inhibited the growth of tumors in patient-derived xenograft (PDX) models. Taken together, our results show that circZFR is an oncogenic circRNA, which promotes the development and spread of CRC in a BCLAF1 and miR-3127-5p-dependent manner. CircZFR is a possible serum biopsy marker for the diagnosis and a desirable target for further treatment of CRC., (© 2024. Science China Press.)

Background: Within the subtypes of breast cancer pathologies, triple-negative breast cancer (TNBC) exhibits the highest degree of malignancy and unfavorable outcome, which has great significance in exploring the molecular mechanisms underlying TNBC. This study especially investigated the expression and function of hsa&#95;circ&#95;0003528 in TNBC., Methods: The expression changes of hsa&#95;circ&#95;0003528 were identified from the GEO database (GSE101123) and validated by RT-qPCR. The clinical significance of hsa&#95;circ&#95;0003528 was evaluated using χ 2 tests and Kaplan-Meier curve analysis. Bioinformatic analysis and dual-luciferase reporter assay were used to identify the potential downstream miRNA of hsa&#95;circ&#95;0003528. The cellular experiments were conducted to evaluate the impact of hsa&#95;circ&#95;0003528 or/and miR-215 on TNBC cells., Results: The hsa&#95;circ&#95;0003528 was selected from the circRNA profile in breast cancer obtained from the GSE101123 dataset. hsa&#95;circ&#95;0003528 expression levels were increased in breast cancer tissues, especially in TNBC tissues. The elevated expression of hsa&#95;circ&#95;0003528 was negatively associated with TNBC patients' overall survival. Silencing of hsa&#95;circ&#95;0003528 hindered the proliferative potential, migration abilities, and invasive capacities of TNBC cells, while downregulation of miR-215 partially diminished the effects of si-hsa&#95;circ&#95;0003528 on TNBC cells., Conclusion: hsa&#95;circ&#95;0003528 is upregulated in TNBC and can facilitate aggressive cellular behaviors by regulating miR-215 expression, hinting at its potential as a biomarker and therapeutic target in the treatment of TNBC., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Circular RNA (circRNA) is covalently closed, single-stranded RNA produced by back-splicing. A few circRNAs have been implicated as functional; however, we lack understanding of pathways that are regulated by circRNAs. Here we generated a pooled short-hairpin RNA library targeting the back-splice junction of 3,354 human circRNAs that are expressed at different levels (ranging from low to high) in humans. We used this library for loss-of-function proliferation screens in a panel of 18 cancer cell lines from four tissue types harbouring mutations leading to constitutive activity of defined pathways. Both context-specific and non-specific circRNAs were identified. Some circRNAs were found to directly regulate their precursor, whereas some have a function unrelated to their precursor. We validated these observations with a secondary screen and uncovered a role for circRERE(4-10) and circHUWE1(22,23), two cell-essential circRNAs, circSMAD2(2-6), a WNT pathway regulator, and circMTO1(2,RI,3), a regulator of MAPK signalling. Our work sheds light on pathways regulated by circRNAs and provides a catalogue of circRNAs with a measurable function., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Ovarian cancer (OC) is among the most common and deadly solid malignancies in women. Despite many advances in OC research, the incidence of OC continues to rise, and its pathogenesis remains largely unknown. Herein, we elucidated the function of hsa&#95;circ&#95;0061179 in OC. The levels of hsa&#95;circ&#95;0061179, miR-143-3p, TIMELESS, and DNA damage repair-related proteins in OC or normal ovarian tissues and cells were measured using real-time quantitative polymerase chain reaction and immunoblotting. The biological effects of hsa&#95;circ&#95;0061179 and miR-143-3p on proliferation, clone formation, DNA damage, and apoptosis of OC cells were detected by the cell counting kit-8 assay, 5-methylethyl-2'-deoxyuridine, flow cytometry, the comet assay, and immunofluorescence staining combined with the confocal microscopy. The interaction among hsa&#95;circ&#95;0061179, miR-143-3p, and TIMELESS was validated by the luciferase reporter assay. Mice tumor xenograft models were used to evaluate the influence of hsa&#95;circ&#95;0061179 on OC growth in vivo. We found that human OC biospecimens expressed higher levels of hsa&#95;circ&#95;0061179 and lower levels of miR-143-3p. Hsa&#95;circ&#95;0061179 was found to bind with miR-143-3p, which directly targets TIMELESS. Hsa&#95;circ&#95;0061179 knockdown or miR-143-3p overexpression suppressed the proliferation and clone formation of OC cells and increased DNA damage and apoptosis of OC cells via the miR-143-3p/TIMELESS axis. Furthermore, we demonstrated that METTL3 could direct the formation of has&#95;circ&#95;0061179 through a specific m6A modification site. YTHDC1 facilitated the cytoplasmic transfer of has&#95;circ&#95;0061179 by directly binding to the modified m6A site. Our findings suggest that hsa&#95;circ&#95;0061179 acts as the sponge of miR-143-3p to activate TIMELESS signaling and inhibits DNA damage and apoptosis in OC cells., (© 2024 The Authors. Molecular Carcinogenesis published by Wiley Periodicals LLC.)

The association of circular RNAs (circRNAs) with non-small cell lung cancer (NSCLC) has been recognized extensively. In view of this, our study particularly surveyed the underlying mechanism of circ-ATAD1 in the disease. First, an analysis of the clinical expression of circ-ATPase family AAA domain containing 1 (ATAD1) was performed, followed by further evaluation of the relationship between circ-ATAD1 expression and prognosis. Then, A549 cells were treated with single transfection or combined transfection with the plasmid vectors that interfere with circ-ATAD1 or miR-191-5p. circ-ATAD1 and miR-191-5p levels were detected by reverse transcription quantitative polymerase chain reaction to verify the transfection success. Then, cell proliferation was checked by cell count kit-8 and clonal formation test. Cell apoptosis was analyzed by flow cytometry. Cell migration and invasion were examined by wound healing assay and Transwell. Finally, the targeting of miR-191-5p to circ-ATAD1 or Forkhead Box K1 (FOXK1) was verified by bioinformation website starBase analysis and dual-luciferase reporter assay. circ-ATAD1 was expressed abundantly in tumor tissues of NSCLC patients and had a predictive value in poor prognosis. circ-ATAD1 underexpression or miR-191-5p overexpression could obstruct A549 cells to behave aggressively, while circ-ATAD1 upregulation or miR-191-5p depletion resulted in the promotion of aggressiveness of A549 cells. Interestingly, circ-ATAD1 could decoy miR-191-5p. miR-191-5p negatively regulated FOXK1 expression, and downregulating miR-191-5p or upregulating FOXK1 rescued circ-ATAD1 downregulation-mediated influences on NSCLC cells. circ-ATAD1 accelerates NSCLC progression by absorbing miR-191-5p to upregulate FOXK1 expression., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Muscle development is a multistep process regulated by diverse gene networks, and circRNAs are considered novel regulators mediating myogenesis. Here, we systematically analyzed the role and underlying regulatory mechanisms of circRBBP7 in myoblast proliferation and differentiation. Results showed that circRBBP7 has a typical circular structure and encodes a 13 -kDa protein. By performing circRBBP7 overexpression and RNA interference, we found that the function of circRBBP7 was positively correlated with the proliferation and differentiation of myoblasts. Using RNA sequencing, we identified 1633 and 532 differentially expressed genes (DEGs) during myoblast proliferation or differentiation, respectively. The DEGs were found mainly enriched in cell cycle- and skeletal muscle development-related pathways, such as the MDM2/p53 and PI3K-Akt signaling pathways. Further co-IP and IF co-localization analysis revealed that VEGFR-1 is a target of circRBBP7 in myoblasts. qRT-PCR and WB analysis further confirmed the positive correlation between VEGFR-1 and circRBBP7. Moreover, we found that in vivo transfection of circRBBP7 into injured muscle tissues significantly promoted the regeneration and repair of myofibers in mice. Therefore, we speculate that circRBBP7 may affect the activity of MDM2 by targeting VEGFR-1, altering the expression of muscle development-related genes by mediating p53 degradation, and ultimately promoting myoblast development and muscle regeneration. This study provides essential evidence that circRBBP7 can serve as a potential target for myogenesis regulation and a reference for the application of circRBBP7 in cattle genetic breeding and muscle injury treatment., (© 2024 Federation of American Societies for Experimental Biology.)

To investigate the potential role and molecular mechanism of circ&#95;0005015 in GBM progression. Circ&#95;0005015, microRNA-382-5p (miR-382-5p), and BTB domain and CNC homolog 1 (BACH1) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation was determined by MTT, colony formation, and EdU assays. Cell apoptosis was analyzed using flow cytometry. Cell migration and invasion were assessed using wound healing and transwell assays. Glucose accumulation and lactate levels were examined by the corresponding kit. RNA pull-down and dual-luciferase reporter assays were performed to confirm the interaction between miR-382-5p and circ&#95;0005015 or BACH1. Protein levels of MMP9, PCNA, and BACH1 were examined using western blot assay. Role of circ&#95;0005015 on tumor growth in vivo was analyzed using a xenograft tumor model. Circ&#95;0005015 content was up-regulated in GBM patients and cells, its knockdown restrained GBM cell proliferation, migration, invasion, glycolysis, and triggered apoptosis. Mechanistically, we found that circ&#95;0005015 could directly interact with miR-382-5p and serve as a miRNA sponge to regulate BACH1 expression. In addition, circ&#95;0005015 knockdown might repress tumor growth in vivo. Circ&#95;0005015 boosted GBM progression via binding to miR-382-5p to up-regulate BACH1, which may offer new effective targets for GBM treatment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Psoriasis is a chronic inflammation-associated skin disorder, and interleukin-22 (IL-22) is involved in psoriasis pathogenesis by boosting the proliferation and migration of keratinocytes. Mounting evidence has shown that circRNAs might play an important role in several aspects of psoriasis. This study is designed to explore the role and mechanism of circ&#95;0056856 in regulating the phenotypes of IL-22-induced keratinocytes (HaCaT cells)., Methods: Circ&#95;0056856, microRNA-197-3p (miR-197-3p), Cyclin-dependent kinase 1 (CDK1), and Wilms tumor 1-associated protein (WTAP) levels were detected using real-time quantitative polymerase chain reaction (RT-qPCR). Cell viability, proliferation, migration, and invasion were analyzed using 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Wound scratch, and Transwell assays. After being predicted by Circinteractome or TargetScan, binding between miR-197-3p and circ&#95;0056856 or CDK1 was verified by a dual-luciferase reporter assay. CDK1 and WTAP protein levels were determined using Western blot. Interaction between WTAP and circ&#95;0056856 was assessed using methylated RNA immunoprecipitation (MeRIP) assay., Results: Increased circ&#95;0056856, CDK1, and WTAP were observed in psoriasis patients and IL-22-treated HaCaT cells. Moreover, circ&#95;0056856 knockdown might repress IL-22-induced HaCaT cell proliferation, migration, and invasion in vitro. In mechanism, circ&#95;0056856 might function as a sponge of miR-197-3p to modulate CDK1 expression, and WTAP improved circ&#95;0056856 expression via m6A methylation., Conclusion: WTAP-guided m6A modified circ&#95;0056856 facilitates IL-22-stimulated HaCaT cell damage through the miR-197-3p/CDK1 axis, which could provide novel insights into psoriasis treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Circβ-catenin, our first reported circRNA, has been reported to mediate tumorigenesis in various cancers. However, its biological functions and underlying mechanisms in colorectal cancer (CRC) remain unknown., Methods: The qRT-PCR examination was used to detect the expression of circβ-catenin, miR-197-3p, and CTNND1 in cells and human tissues. Western blot was conducted to detect the protein expression levels. The biological function of circβ-catenin was verified by MTT, colony formation, wound healing, and transwell assays. The in vivo effects of circβ-catenin were verified by nude mice xenograft and metastasis models. The regulatory network of circβ-catenin/miR-197-3p/CTNND1 was confirmed via dual-luciferase reporter and RIP assays., Results: In the present study, circβ-catenin was found to promote CRC cell proliferation and metastasis in vitro and in vivo. Mechanistically, circβ-catenin served as miRNA decoy to directly bind to miR-197-3p, then antagonized the repression of the target gene CTNND1, and eventually promoted the malignant phenotype of CRC. More interestingly, the inverted repeated Alu pairs termed AluJb1/2 and AluY facilitated the biogenesis of circβ-catenin, which could be partially reversed by EIF4A3 binding to Alu element AluJb2., Conclusions: Our findings illustrated a novel mechanism of circβ-catenin in modulating CRC tumorigenesis and metastasis, which provides a potential therapeutic target for CRC patients., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

The aim of the present research is to explore the biological function and mechanism of circ&#95;0082319 in HCC progression. Circ&#95;0082319, microRNA-505-3p (miR-505-3p), protein tyrosine kinase 2 (PTK2), and human antigen R (HuR, also known as ELAVL1) level were detected by real-time quantitative polymerase chain reaction. Cell viability, proliferation, apoptosis, invasion, and angiogenesis were measured using (4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays. Protein levels of c-Myc, MMP2, PTK2, and HuR were examined using western blot. The glycolysis levels were assessed using specific kits. Binding between miR-505-3p and circ&#95;0082319 or PTK2 was predicted by Starbase and verified by a dual-luciferase reporter and RNA immunoprecipitation assays. The biological role of circ&#95;0082319 on HCC tumor growth was examined using xenograft tumor model in vivo. Circ&#95;0082319, PTK2, and HuR were highly expressed, and miR-505-3p was reduced in HCC samples and cell lines. Moreover, the knockdown of circ&#95;0082319 might repress HCC cell proliferation, invasion, angiogenesis, and induce apoptosis in vitro. In mechanism, circ&#95;0082319 served as a sponge of miR-505-3p to regulate PTK2 expression. HuR expedited circ&#95;0082319 expression in HCC cells. HuR-mediated circ&#95;0082319 might accelerate HCC cell proliferation, invasion, angiogenesis, and suppress apoptosis by the miR-505-3p/PTK2 axis, hinting at a promising therapeutic target for HCC treatment., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Circular RNA (circRNA) is a type of non-coding RNA generated from back-splicing the reactions of linear RNA. It plays an important role in various cellular and biological processes. However, there are few studies about the regulatory effect of circRNAs on cashmere fiber traits in cashmere goats. In this study, the expression profiles of circRNAs in skin tissue were compared between Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats, with a significant difference in cashmere fiber yield, cashmere fiber diameter, and cashmere fiber color, using RNA-seq. A total of 11,613 circRNAs were expressed in the caprine skin tissue, and their type, chromosomal distribution, and length distribution were characterized. A total of 115 up-regulated circRNAs and 146 down-regulated circRNAs in LC goats were screened compared to ZB goats. The authenticity of 10 differentially expressed circRNAs was validated by detecting their expression levels and the head-to-tail splice junction using RT-PCR and DNA sequencing, respectively. The parent genes of differentially expressed circRNA were mainly enriched in some Gene Ontology (GO) terms and pathways related to cashmere fiber traits, such as the canonical Wnt signaling pathway, which is involved in the regulation of cell promotion, stem cell proliferation, Wnt signaling pathway regulation, epithelial morphogenesis, MAPK signaling pathway, and cell adhesion molecules pathway. Eight differentially expressed circRNAs were further selected to construct a circRNA-miRNA network, and some miRNAs that were previously reported as related to fiber traits were found in the network. This study provides a deep understanding of the roles of circRNAs in the regulation of cashmere fiber traits in cashmere goats and the involvement of differential splicing in phenotypic expression according to breed and region. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) have been confirmed to be an important modulator and therapeutic target of cervical cancer (CC). The aim of this study is to explore the role and mechanism of circ&#95;0081723 in CC progression. Circ&#95;0081723, microRNA-545-3p (miR-545-3p), and CREB3 regulatory factor (CREBRF) levels were detected using quantitative real-time PCR (qRT-PCR) assay. CREBRF, ki-67, Bcl-2 related X protein (Bax), and E-cadherin expression levels were determined using western blot (WB) and immunohistochemistry (IHC) assays. Cell proliferation was assessed using Cell Counting Kit-8 (CCK-8), cell colony formation, and 5-ethynyl-2'-deoxyuridine (EdU) assays. Flow cytometry was used to measure cell apoptosis.  Cell migration and invasion were examined using Transwell assay. Interaction between miR-545-3p and circ&#95;0081723 or CREBRF was verified using dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assays. The biological role of circ&#95;0081723 on CC growth was examined using the xenograft tumor model in vivo. Circ&#95;0081723 and CREBRF were increased, and miR-545-3p was decreased in CC tissues and cells. Circ&#95;0081723 silencing suppressed CC cell growth and motility whereas boosted CC cell apoptosis. Besides, circ&#95;0081723 acted as a molecular sponge for miR-545-3p, and circ&#95;0081723 knockdown-induced effects were largely reversed by miR-545-3p downregulation in CC cells. Moreover, miR-545-3p repressed CC progression by targeting CREBRF.  Circ&#95;0081723 absence blocked xenograft tumor growth in vivo. Circ&#95;0081723 stimulated CC cell malignant behaviors by regulating the miR-545-3p/CREBRF pathway, providing a possible circRNA-targeted therapy for CC., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Circular RNAs (circRNAs) have been found to be abnormally expressed in many cancers, including colorectal cancer (CRC). Circ&#95;0053277 has been found to mediate CRC malignant processes and may be a key regulator for CRC progression. Therefore, its role and potential molecular mechanism in CRC process deserve further investigation. Quantitative real-time PCR was used to detect the expression levels of circ&#95;0053277, microRNA-520 h (miR-520 h) and hexokinase 1 (HK1). Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine assay, flow cytometry, wound healing assay, transwell assay, and tube formation assay were used to detect CRC cell proliferation, apoptosis, migration, invasion, and angiogenesis. The protein levels of apoptosis-related markers and HK1 were detected by western blot. The relationship between circ&#95;0053277 and miR-520 h or miR-520 h and HK1 in CRC cells was verified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay. Cell glycolysis was assessed by detecting glucose uptake and lactate production. The effect of silenced circ&#95;0053277 on CRC tumor growth was evaluated by xenograft model in vivo. Our study found that circ&#95;0053277 expression was elevated in CRC tissues and cells. Moreover, circ&#95;0053277 knockdown suppressed CRC cell proliferation, angiogenesis, migration and invasion, while promoting apoptosis. In terms of mechanism, circ&#95;0053277 sponged miR-520 h, and HK1 was the target of miR-520 h. Meanwhile, miR-520 h inhibitor reversed the inhibitory effect of circ&#95;0053277 silencing on CRC cell progression, and HK1 overexpression also overturned the suppressive effect of miR-520 h on CRC cell growth, angiogenesis and metastasis. Moreover, circ&#95;0053277 knockdown inhibited the glycolysis of CRC cells by regulating miR-520 h/HK1 pathway. In addition, knockdown of circ&#95;0053277 reduced CRC tumor growth in vivo. Circ&#95;0053277 promoted CRC cell growth, angiogenesis, metastasis and glycolysis by miR-520 h/HK1 pathway, confirming that circ&#95;0053277 might be a potential clinical target for CRC treatment., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Methyltransferase like 3 (METTL3) has been reported to promote tumorigenesis of multiple myeloma (MM), however, the molecular mechanism still needs further research. The N6-methyladenosine (m6A) level in tissues or cells was measured by m6A kit and dot blot assay. The mRNA and protein expression were detected by quantitative real-time PCR (RT-qPCR) and Western blot, respectively. The cell counting kit-8 and colony formation assay were used to detect the cell proliferation. Coimmunoprecipitation (Co-IP) experiment verified the binding of two proteins. The luciferase reporter experiment demonstrated the targeted binding of miR-182-5p and CaMKII inhibitor 1 (CAMK2N1). More importantly, tumor growth was measured in xenograft mice. Our data showed that the expression of METTL3 was significantly increased in MM patients' samples and MM cells. METTL3 overexpression promoted MM cells proliferation, and METTL3 knockdown inhibited MM cells proliferation. Mechanically, METTL3-dependent m6A participated in DiGeorge syndrome critical region 8 (DGCR8)-mediated maturation of pri-miR-182. Upregulation of miR-182-5p further enhanced the promoting proliferation effect of METTL3 overexpression on MM cells. Moreover, the luciferase reporter gene experiment proved that miR-182-5p targetedly regulated CAMK2N1 expression. Xenograft tumor in nude mice further verified that METTL3 promoted MM tumor growth through miR-182/CAMK2N1 signal axis. In summary, the METTL3/miR-182-5p/CAMK2N1 axis plays an important role in MM tumorigenesis, which may provide a new target for MM therapy., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Circular RNAs (circRNAs) play an important role in the progression of atherosclerosis (AS). This study aimed to explore the exact role and mechanism of circ&#95;0002984 in oxidized low-density lipoprotein (ox-LDL)-mediated human vascular smooth muscle cells (HVSMCs). The model of smooth muscle cell phenotype switching was constructed by treating HVSMCs with ox-LDL. The levels of circ&#95;0002984, let-7a-5p, and kruppel-like factor 5 (KLF5) were measured by quantitative real-time PCR or western blot assay. Cell proliferation, migration, and apoptosis were detected by Cell Counting Kit-8 (CCK-8), EdU staining, wound healing assay, transwell assay, and flow cytometry. The expression of cleaved-caspase-3 and KLF5 was examined by western blot. The relationship between let-7a-5p and circ&#95;0002984 or KLF5 was verified by dual-luciferase reporter assay or RIP assay. The results showed that circ&#95;0002984 and KLF5 were up-regulated, while let-7a-5p was down-regulated in AS patients and ox-LDL-disposed HVSMCs. Silence of circ&#95;0002984 suppressed proliferation and migration, and promoted apoptosis in ox-LDL-stimulated HVSMCs. Moreover, circ&#95;0002984 sponged let-7a-5p to regulate the proliferation, migration, and apoptosis in ox-LDL-resulted HVSMCs. In addition, KLF5 was a target of let-7a-5p and its overexpression reversed the effect of let-7a-5p on the proliferation, migration, and apoptosis in ox-LDL-treated HVSMCs. Also, circ&#95;0002984 positively regulated KLF5 expression by absorbing let-7a-5p. The promotion effect of circ&#95;0002984 on the proliferation and migration of ox-LDL-treated HVSMCs was reversed by KLF5 silencing. Taken together, depletion of circ&#95;0002984 inhibited the proliferation and migration of ox-LDL-stimulated HVSMCs, which might be achieved by modulating the let-7a-5p/KLF5 axis., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Papillary thyroid cancer (PTC) is the most prevalent histological type of differentiated thyroid malignancy. Circular RNAs (circRNAs) have been implicated in the pathogenesis and progression of various cancers. circTIAM1 (hsa&#95;circ&#95;0061406) is a novel circRNA with aberrant expression in PTC. However, its functional roles in PTC progression remain to be investigated., Methods: The expression levels of circTIAM1 in the PTC and the matched para-cancerous tissues were detected by quantitative real-time reverse-transcription PCR (qRT-PCR). The subcellular localization of circTIAM1 was examined by fluorescence in-situ hybridization (FISH). Kaplan-Meier plot was used to analyze the association of clinicopathological features with circTIAM1 expression. Bioinformatics databases were utilized to predict the target miRNAs of circTIAM1 and the downstream target mRNAs. RNA pull-down, RIP assay, and dual-luciferase reporter assay were used to confirm the interactions. Functional experiments, such as CCK-8, EDU staining, and apoptosis assays, as well as in vivo xenograft model were employed to explore the impacts of circTIAM1, miR-338-3p, and LIM/SH3 protein 1 (LASP1) on the malignant phenotype of the PTC cells., Results: CircTIAM1 was highly expressed in PTC cells. Moreover, circTIAM1 silencing suppressed the proliferation and invasion of PTC cells in vitro and impaired tumorigenesis in vivo . Furthermore, miR-338-3p was verified as a miRNA target of circTIAM1. LASP1 was also identified as a downstream target of miR-338-3p. The anti-tumorigenic effect of miR-338-3p overexpression and the pro-tumorigenic effect of LASP1 was further explored by functional assays, which demonstrated that circTIAM1 modulated the PTC progression through targeting miR-338-3p/LASP1 axis., Conclusion: The overexpression of circTIAM1 is associated with the malignant progression of PTC. A high level of circTIAM1 promotes the malignancy of PTC cells via the miR-338-3p/LASP1 axis., Competing Interests: The authors declare that they have no conflict of interest., (© 2024 The Authors.)

Circular RNAs are emerging players in human cancers, including esophageal squamous cell carcinoma (ESCC). Herein, we assessed the expression level of circ&#95;0023990 and explored the molecular mechanisms of circ&#95;0023990 in ESCC. circ&#95;0023990, miR-6884-5p, and PAK1 expressions in ESCC tissues and cells were detected by quantitative real-time polymerase chain reaction and western blot. ESCC cells were transfected with different constructs to alter the expression of circ&#95;0023990, miR-6884-5p, and PAK1. The effect of circ&#95;0023990 on the proliferation, invasion, and glycolysis of ESCC cells was observed. The interaction between circ&#95;0023990 and miR-6884-5p and between miR-6884-5p and PAK1 were explored. A mouse model of ESCC was established to study the in vivo effect of circ&#95;0023990 knockdown on tumor formation.The expression levels of circ&#95;0023990 was upregulated in ESCC tissues and cells. Inhibiting circ&#95;0023990 suppressed the proliferation, invasion, and glycolysis of ESCC cells. circ&#95;0023990 might target miR-6884-5p and consequently modulate the expression and activity of PAK1. Knockdown of circ&#95;0023990 led to significantly reduced tumor volume and weight in mice with ESCC.These findings overall suggest an oncogenic role of circ&#95;0023990 in ESCC. Future research is warranted to confirm the expression pattern and clinical significance of circ&#95;0023990 in ESCC., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Non-small-cell lung cancer (NSCLC) stands as a prevalent subtype of lung cancer, with circular RNAs emerging as key players in cancer development. This study elucidates the role of circRNA-CPA4 in NSCLC. Elevated circRNA-CPA4 expression in NSCLC lines was confirmed through qRT-PCR. Silencing circRNA-CPA4 with shRNA revealed, through CCK-8, colony formation, and flow cytometry assays, a notable constraint on proliferation and promotion of apoptosis in NSCLC cells. Subcellular localization analysis, RNA immunoprecipitation, and expression level assessments were employed to decipher the intricate interplay among miR-1183, circRNA-CPA4, and PDPK1. Results demonstrated heightened circRNA-CPA4 levels in NSCLC, and its knockdown curtailed NSCLC growth in vivo. Acting as a molecular sponge for miR-1183, circRNA-CPA4 regulated PDPK1 expression. Conversely, inhibiting miR-1183 counteracted the impact of circRNA-CPA4 silencing, reinstating NSCLC cell proliferation, and impeding apoptosis. Overall, this study unveils a novel mechanism: circRNA-CPA4 promotes PDPK1 expression by sequestering miR-1183, fostering NSCLC cell proliferation, and hindering apoptosis., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Circular RNAs (circRNAs) play a crucial regulatory role in malignant tumor metastasis. This study focused on the role of bone metastasis-related circRBMS3 in breast cancer. Two circRNA microarray datasets were obtained from the GEO database and overlapped bone metastasis-related circRNAs in breast cancer. CircRBMS3 expression was validated in bone metastasis tissues by RT-qPCR. Cellular CCK-8 assay and Transwell assays were performed to measure the effect of circRBMS3 in breast cancer cells. Bioinformatic analyses were performed to identify the binding miRNAs of circRBMS3 and downstream mRNAs. Online database STRING and Cytoscape software were used to analyze PPI interaction and conduct the ceRNA network. GEO database analysis showed that circRBMS3 was one of the upregulated circRNAs among all the metastatic cells. CircRBMS3 was increased in bone metastasis breast cancer tissues compared to non-bone metastasis tissues and associated with poor 3-year overall survival. CircRBMS3 knockdown repressed breast cancer cell proliferation, migration, and invasion, as well as bone resorption gene and osteoclast phenotype gene expression. CircRBMS3 was found to bind withmiR-654-3p. Subsequently, downstream mRNAs were predicted, and the circRBMS3 miR-654-3p-mRNA network was established. In conclusion, circRBMS3 expression was upregulated in bone metastasis breast cancer and might be a potential prognostic marker for patients. Silencing circRBMS3 restrained breast cancer cell proliferation, migration, and invasion, as well as associated with bone metastasis. The circRBMS3-miR-654-3p-mRNAs network elucidated potential mechanisms underlying bone metastasis in breast cancer., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

BC (breast cancer) is the leading cause of cancer death in women. Exosome component 2 (EXOSC2), an RNA exosome component, is elevated in BC tissues and may relate to BC carcinogenesis. In this work, the high EXOSC2 expression was correlated with TNM (Tumor Node Metastasis) stage. Moreover, overexpression of EXOSC2 enhanced tumorigenic capacity of BC cells via facilitating cell proliferation and cell cycle progression, increasing migration and angiogenesis, as well as exacerbating xenograft formation in vivo. Whereas, EXOSC2 knockdown showed anti-cancer effects, including inhibition of cell proliferation and angiogenesis. Mechanistically, EXOSC2 activated the wnt/β-catenin pathway, which was also abolished by EXOSC2 knockdown. In addition, there were m6A methylation modification sites in the mRNA of EXOSC2. WTAP (Wilms tumor 1-associated protein) bound to EXOSC2 mRNA and increased its m6A methylation, resulting in extending the half-life of EXOSC2 mRNA. Luciferase data also confirmed that WTAP enhanced EXOSC2 mRNA stability through binding with the 3'-UTR containing m6A sites. Furthermore, WTAP silencing exhibited cancer-inhibiting effects on cell viability, cell cycle progression and tube formation, which was effectively reversed by EXOSC2 overexpression. In conclusion, our results demonstrate that EXOSC2 promotes the malignant behaviors of BC cells via activating the wnt/β-catenin pathway. In addition, EXOSC2 mediates the function of WTAP which contributes to the m6A modification of EXOSC2. Totally, this study suggested that EXOSC2 mediated the pro-tumor role of WTAP via activating the wnt/β-catenin signal., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The involvement of circular RNAs (circRNAs) in laryngeal squamous cell carcinoma (LSCC) carcinogenesis has gradually been proposed. Herein, we aimed to explore the function and mechanism of circPRRC2C in LSCC. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used for detecting the content of genes and proteins. In vitro experiments were conducted using 5-ethynyl-2'-deoxyuridine, colony formation, flow cytometry, and transwell assays. The binding between miR-136-5p and circPRRC2C or Homeobox D11 (HOXD11) was confirmed by using the dual-luciferase reporter assay. The murine xenograft model was established for in vivo analysis. The commercial kit was used for exosome separation. CircPRRC2C is a stable circRNA, and was highly expressed in LSCC tissues and cell lines. Functionally, circPRRC2C deficiency impaired LSCC cell proliferation, migration and invasion but induced cell apoptosis in vitro and impeded tumor growth in vivo, however, circPRRC2C overexpression showed the exact opposite effects. Mechanistically, circPRRC2C directly targeted miR-136-5p, which showed inhibitory effects on the growth and mobility of LSCC cells. Meanwhile, miR-136-5p directly targeted HOXD11, and circPRRC2C/miR-136-5p/HOXD11 formed a feedback loop in LSCC cells. Further rescue assays exhibited that circPRRC2C exerted its effects by miR-136-5p/HOXD11 axis. In addition, circPRRC2C was stably packaged into exosomes and showed potential diagnostic value for LSCC. CircPRRC2C acted as an oncogene to promote LSCC cell oncogenic phenotypes via miR-136-5p/HOXD11 axis, besides, circPRRC2C was stably packaged into exosomes, indicating the potential application of circPRRC2C-targeting agents in the treatment in LSCC., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Recent statistics show that breast cancer is among the most frequent cancers in clinical practice. It is also the second-leading cause of cancer-related deaths among women worldwide. CircRNAs are a new class of endogenous regulatory RNA molecules whose 5’ end and 3’ end are connected together to form a covalently closed single-stranded loop by back-splicing. CircRNAs present the advantages of disease-specific expression and excellent expression stability, and they can modulate gene expression at posttranscriptional and transcriptional levels. CircRNAs are abnormally expressed in multiple cancers, such as breast cancer, and drive the initiation and progression of cancer. In this review, we describe current knowledge about the functions of circRNAs and generalize their roles in various aspects of breast cancer, including cell proliferation, cell cycle, apoptosis, invasion and metastasis, autophagy, angiogenesis, drug resistance, and tumor immunity, and their prognostic and diagnostic value. This may add to a better understanding of the functions and roles of circRNAs in breast cancer, which may become new diagnostic and predictive biomarkers of breast cancer.

Circular RNAs (circRNAs) are demonstrated to be involved in psoriasis progression. CircRNAs can act as RNA-binding protein (RBP) sponges. Here, we investigated the action of circAKR1B10 in psoriasis, and explored the potential proteins interacted with circAKR1B10. Levels of genes and proteins were assayed by qRT-PCR and western blotting analyses. Keratinocytes in functional groups were treated with interleukin (IL)-22. Functional analysis were conducted using MTT, 5-ethynyl-2'-deoxyuridine (EdU), and transwell assays, respectively. Interaction analysis among circAKR1B10, Eukaryotic initiation factor 4 A-III (EIF4A3) and Aurora Kinase A (AURKA) was conducted using bioinformatics analysis, RNA pull-down assay, and RNA immunoprecipitation (RIP) assay. CircAKR1B10 was highly expressed in psoriasis patients and IL-22-induced keratinocytes. Functionally, knockdown of circAKR1B10 abolished IL-22-induced proliferation, migration and invasion in keratinocytes. AURKA expression was also higher in psoriasis patients and IL-22-induced keratinocytes, and was negatively correlated with circAKR1B10 expression. Moreover, AURKA silencing reduced the proliferative, migratory and invasive abilities of IL-22-induced keratinocytes. Mechanistically, circAKR1B10 interacted with EIF4A3 protein to stabilize and regulate AURKA expression. CircAKR1B10 contributes to IL-22-induced proliferation, migration and invasion in keratinocytes via up-regulating AURKA expression through interacting with EIF4A3 protein., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Exosomes from cancer cells function as carriers to spread or transport specific microRNAs (miRNAs) to distant sites to exert their effects, but the mechanism of exosomal miRNA action in esophageal squamous cell carcinoma (ESCC) has not been fully explained. Therefore, in this study, we were interested in the impact of exosomal miR-196a-5p in ESCC progression. We found that miR-196a-5p was expressed enriched in clinical tissues, ESCC cells, and exosomes. Functionally, depletion of miR-196a-5p impeded ESCC cell growth, migration, and invasion, whereas overexpression of miR-196a-5p produced the opposite results. Moreover, enhancement of exosomal miR-196a-5p in recipient ESCC cells triggered more intense proliferation and migration. Mechanistically, we identified integral membrane protein 2B (ITM2B) as a direct target of miR-196a-5p. Silencing of ITM2B partially counteracted the inhibitory effect of miR-196a-5p inhibitors on the malignant phenotype of ESCC. Furthermore, in vivo, lower miR-196a-5p levels triggered by the introduction of antagomiR-196a-5p resulted in the generation of smaller volume and weight xenograft tumors. Thus, our results demonstrated novel mechanisms of exosomal and intracellular miR-196a-5p-mediated ESCC growth and migration and identify the interaction of miR-196a-5p with ITM2B. These works might provide new targets and basis for the development of clinical treatment options for ESCC., (© 2024 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Purpose: Circular RNAs (circRNAs) are increasingly recognized for their important roles in various cancers, including papillary thyroid cancer (PTC). The specific mechanisms by which the circLIF receptor subunit alpha (circLIFR, hsa&#95;circ&#95;0072309) influences PTC progression remain largely unknown., Methods: In our study, CircLIFR, miR-429, and TIMP2 levels were assessed using reverse transcription-quantitative PCR. The roles of circLIFR and miR-429 in PTC cells were determined using Cell Counting Kit-8, colony formation, wound healing, and Transwell assays. Western blotting was utilized to examine the levels of TIMP2. The direct interaction between circLIFR, TIMP2, and miR-429 was confirmed using dual-luciferase reporter, RNA immunoprecipitation, and fluorescence in situ hybridization assays., Results: In PTC tissues and cells, a decrease in circLIFR and TIMP2 levels, accompanied by an increase in miR-429 levels, was observed. Overexpression of circLIFR or downregulation of miR-429 effectively suppressed the proliferation and migration of PTC cells. Conversely, the knockdown of circLIFR or overexpression of miR-429 had the opposite effect. Furthermore, circLIFR overexpression suppressed tumor growth in vivo. Mechanistically, circLIFR modulated TIMP2 expression by serving as a sponge for miR-429. Rescue experiments indicated that the antitumor effect of circLIFR could be reversed by miR-429., Conclusion: This study confirmed circLIFR as a novel tumor suppressor delayed PTC progression through the miR-429/TIMP2 axis. These findings suggested that circLIFR held promise as a potential therapeutic target for PTC., (© 2024. The Author(s).)

Current study aims to investigate the biological function of circular RNA (circRNA, circ&#95;0000337) in cervical cancer (CC). Bioinformatic analyses were used to predict targets for circ&#95;0000337 and miR-155-5p, and analyze the gene expression differences between cervical squamous cell carcinoma and endocervical adenocarcinoma (CESC) tissues and normal tissues. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were applied to assess mRNA and protein expressions of circ&#95;0000337, microRNA-155-5p (miR-155-5p) and member RAS oncogene family (RAB3B), respectively. Following the establishment of gain/loss-of-function models, CCK-8 was performed to evaluate cell proliferation. Bioinformatics analysis, dual-luciferase reporter assay and RNA immunoprecipitation (RIP) were used to identify the interaction in circ&#95;0000337, miR-155-5p, and RAB3B. Circ&#95;0000337 and RAB3B were upregulated, while miR-155-5p was downregulated in CC tissues and cell lines. circ&#95;0000337 overexpression promoted cell proliferation, circ&#95;0000337 knock down inhibited cell proliferation by sponging miR-155-5p. RAB3B was a target of miR-155-5p which was positively regulated by circ&#95;0000337. In the collected CC tissues, there was a negative correlation between miR-155-5p and circ&#95;0000337 or RAB3B, and a positive correlation between circ&#95;0000337 and RAB3B. miR-155-5p was positively, while RAB3B was negatively correlated with OS in patients with CC, and they were negatively correlated. In conclusion, circ&#95;0000337 upregulates RAB3B by sponging miR-155-5p to promote CC cell proliferation., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Bisphenol A (BPA) is an endocrine disruptor with reproductive toxicity. Further, 1,25-dihydroxyvitamin D3 (VD 3 ) plays an important role in male reproduction by binding vitamin D receptor (VDR) and mediating the pleiotropic biological actions that include spermatogenesis. However, whether VD 3 /VDR regulates the effect of BPA on Leydig cells (LCs) injury remains unknown. This study aimed to explore the effects of VD on BPA-induced cytotoxicity in mouse LCs. Hereby, LCs treated with BPA, VD 3 , or both were subjected to the assays of cell apoptosis, proliferation, autophagy, and levels of target proteins. This study unveiled that cell viability was dose-dependently reduced after exposure to BPA. BPA treatment significantly inhibited LC proliferation, induced apoptosis, and also downregulated VDR expression. By jointly analyzing transcriptome data and Comparative Toxicogenomics Database (CTD) data, autophagy signaling pathways related to testicular development and male reproduction were screened out. Therefore, the autophagy phenomenon of cells was further detected. The results showed that BPA treatment could activate cell autophagy, Vdr -/- inhibits cell autophagy, and active VD 3 does not have a significant effect on the autophagy of normal LCs. After VD 3 and BPA were used in combination, the autophagy of cells was further enhanced, and VD 3 could alleviate BPA-induced damage of LCs. In conclusion, this study found that supplementing VD 3 could eliminate the inhibition of BPA on VDR expression, further enhance LCs autophagy effect, and alleviate the inhibition of LCs proliferation and induction of apoptosis by BPA, playing a protective role in cells. The research results will provide valuable strategies to alleviate BPA-induced reproductive toxicity., (© 2024 Institute of Food Technologists.)

Circular RNAs (circRNAs) participate in development of malignancies through its active role as a "miRNA sponge." Their roles in type 1 diabetes mellitus (T1DM) pathogenesis are elusive. Here, the important role of circRNAs in T1DM was explored. circRNA profiling was performed for isolated CD4+ T cells from blood of T1DM and healthy volunteers. There were 257 differentially expressed circRNAs. Only three upregulated DEcircRNAs (hsa_circ_0000324, hsa_circ_0001853, and hsa_circ_0068797) were consistent with the GEO database. Through KEGG analyses, it was found that the three DEcircRNAs were associated with 11 miRNAs and 8 immune-related target genes (mRNA). Further analysis found that four miRNAs, two circRNAs, and four mRNAs were associated with nine circRNA-miRNA-mRNA networks. This confirmed the requirements of sponge mechanisms. The qRT-PCR analysis revealed that circRNA000324/miRNA675-5p/MAPK14 and circRNA000324/miRNA-675-5p/SYK may be potential mechanisms in regulation of differentiation and proliferation of CD4+ T cell in patients with T1DM. Therefore, targeting circRNA to regulate cellular immune responses by regulating CD4+ T cell differentiation may be a new strategy for the treatment of T1DM. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are single-stranded, covalently closed noncoding RNAs without 3′ and 5′ ends. Evidence demonstrated that circRNAs are abundant, stable and able to show cell/tissue-specific expression, which structure features show potential for noninvasive molecular biomarkers of tumors. CircRNAs express differentially and play an important role in many kinds of neoplasms by miRNA sponges, interaction with RNA binding proteins, modulating the stability of mRNAs, regulating gene transcription and translation proteins. There are no specific biomarkers for early warning and potential therapeutic targets currently. Many studies have demonstrated differential expression of circRNAs function vitally on singnal pathway and gene expression in the initiation and development of cervical cancer. CircRNAs involve in circRNA-miRNA-target gene axis mainly through miRNA sponges to promote cervical cancer cell proliferation, invasion and metastasis, and associate with tumor size, clinical stage, metastatic lymph nodes and poor prognosis. [ABSTRACT FROM AUTHOR]

Prostate cancer (PCa) ranks as the second most prevalent cancer among males globally. However, the exact mechanisms underlying its progression remain inadequately elucidated. The present study sought to investigate the role and underlying molecular mechanism of hsa&#95;circ&#95;0001671 (circ&#95;0001671) in the pathogenic behavior of PCa cells. Guided by the ceRNA theory, miR-27b-3p was employed to identify circRNAs that could potentially regulate Bloom Syndrome Protein (BLM). A series of experimental approaches including bioinformatics, luciferase assays, Fluorescent In Situ Hybridization (FISH), RNA-pulldown, and RNA Immunoprecipitation (RIP) were utilized to validate the miRNA sponge function of circ&#95;0001671. Divergent primer PCR, RNase R treatments, and Sanger sequencing were conducted for the identification of circ&#95;0001671. Quantitative RT-PCR and Western blot analyses were performed to validate gene expression levels. Both in vitro and in vivo experiments were conducted to assess the functional role of circ&#95;0001671 in PCa cells.It was observed that the expression levels of circ&#95;0001671 and BLM were significantly elevated in PCa tissues and cell lines, whereas miR-27b-3p showed decreased expression. Circ&#95;0001671 was found to promote cellular proliferation, migration, and invasion, while inhibiting apoptosis. In vivo assays confirmed that circ&#95;0001671 facilitated tumor growth. Further mechanistic studies revealed that circ&#95;0001671 acted as a competing endogenous RNA (ceRNA) for BLM by sponging miR-27b-3p. The oncogenic role of circ&#95;0001671 in PCa was shown to be modulated through the miR-27b-3p/BLM axis. In conclusion, circ&#95;0001671 exerts an oncogenic effect in prostate cancer through the regulation of BLM by sponging miR-27b-3p, thus suggesting a novel molecular target for the treatment of PCa., (© 2024. The Author(s).)

• Differentially expressed circRNAs (DECs) are screen from circRNA microarray. • CircRNA regulated network (CMMC) was constructed using the algorithm (RWR). • CircFRMD4, circPIGB and circ NUP214 are potential novel biomarkers for MG. • CircFRMD4 sponging miR-145-5p regulate Jurkat cells proliferation. • CircFRMD4 participate in the development of MG via circFRMD4/miR145-5p axis. Recent studies have revealed that circRNA can serve as ceRNA to participate in multiple autoimmune diseases. Our study aims to explore the key circRNA as ceRNA and biomarker for MG. Methods: We used circRNA microarray to explore differentially expressed circRNAs (DECs) from MG and compare with control. Then, we predicted the target miRNA associated with DECs and screened miRNAs by the algorithm of random walk with restart (RWR). Next, we constructed the circRNA-miRNA-mRNA ceRNA regulated network (CMMC) to identify the hub objects. Following, we detected the expression of hub-circRNAs by RT-PCR. We verify has_circ_0004183 (circFRMD4) sponging miR-145-5p regulate cells proliferation using luciferase assay and CCK-8. Results: We found that the expression level of circFRMD4 and has_circ_0035381 (circPIGB) were upregulated and has_circ_0089153(circ NUP214) had the lowest expression level in MG. Finally, we proved circFRMD4 sponging miR-145-5p regulate Jurkat cells proliferation. CircFRMD4 take part in the genesis and development of MG via circFRMD4/miR145-5p axis. Conclusions: We found that circFRMD4, circPIGB and circNUP214 can be considered as valuable potential novel biomarkers for AchR + MG. CircFRMD4 participate in the development of AchR + MG via targeting binding with miR-145-5p. [ABSTRACT FROM AUTHOR]

Background: Pulpitis often are characterized as sustained inflammation and impaired pulp self-repair. Circular RNAs (circRNAs) have been reported to be involved in the development of inflammation, but their influence in pulpitis is still unidentified, which was examined in our research. Methods: In this study, TNF-α (20 ng/mL) was used to treat DPSCs, then MTS identified cell proliferation. The circRNAs profile in DPSCs with or without TNF-α treatment was evaluated using RNA sequencing and subsequently by bioinformatics analysis. After that, the circular structure was assessed using agarose gel electrophoresis, followed by Sanger sequencing. And the circRNAs expression was ratified using quantitative real-time polymerase chain reaction in cell and tissues samples. Additionally, the plausible mechanism of circRNAs was envisaged, and the circRNA-miRNA-mRNA linkage was plotted using Cytoscape. Results: The treatment of TNF-α inhibited cell proliferation capabilities in DPSCs, which also made 1195 circRNA expressions undergo significant alterations. Among these changes, 11 circRNAs associated with inflammation were chosen for circular structure verification, and only seven circRNAs (hsa_circ_0001658, hsa_circ_0001978, hsa_circ_0003910, hsa_circ_0004314, hsa_circ_0004417, hsa_circ_0035915, and hsa_circ_0002545) had circular structure. Additionally, five circRNAs expressions (hsa_circ_0001978, hsa_circ_0003910, hsa_circ_0004314, hsa_circ_0004417, and hsa_circ_0035915) had significantly altered between with or without TNF-α treated DPSCs. Furthermore, hsa_circ_0001978 and hsa_circ_0004417 were increased in patients suffering from pulpitis. Furthermore, their ceRNA linkage and Kyoto Encyclopedia of Genes and Genomes analysis suggested that these two circRNAs may participate in the inflammation development of pulpitis via mitogen-activated protein kinase and the Wnt signaling pathway. Conclusion: This study revealed that the circRNAs profile was altered in TNF-α treated DPSCs. Also, hsa_circ_0001978 and hsa_circ_0004417 may be involved in the inflammation progress of pulpitis. These outcomes provided the latest information for additional research on pulpitis. [ABSTRACT FROM AUTHOR]

Introduction: Colorectal cancer (CRC) is the second most common and fatal cancer in China. circRNAs are different expressed between tumor and non-tumor tissues, and they are proved to be correlated with tumorigenesis and cancer progression., Objective: We aimed to explore the biological and molecular function of hsa&#95;circ&#95;0005939 in CRC., Methods: We collected and compared ten CRC tissues and four noncancerous tissues and performed circRNA sequencing. We investigated the hsa&#95;circ&#95;0005939 expression in fresh tissues from CRC and adjacent tissues by qPCR. Meanwhile, functional roles of hsa&#95;circ&#95;0005939 in CRC cells were explored by CCK-8, colony formation, wounding healing, cell apoptosis and western blot assays. RNA-FISH was used to confirm the cellular distribution of hsa&#95;circ&#95;0005939. Bioinformatic prediction and luciferase reporter assay were used to determine the mechanisms of hsa&#95;circ&#95;0005939., Results: Our results indicated that hsa&#95;circ&#95;0005939 was up-regulated in CRC tissues and cells. Up-regulation of hsa&#95;circ&#95;0005939 was associated with the occurrence and the number of lymph node metastasis of CRC. Hsa&#95;circ&#95;0005939 down-regulation inhibited cell proliferation, increased cell apoptosis and caused G2 phase arrest of CRC cells. Mechanistically, luciferase assay revealed that hsa&#95;circ&#95;0005939 acts as a molecular sponge for miR-4693-3p and then enhanced Ubiquitin Like With PHD And Ring Finger Domains 1 binding protein 1 like (UHRF1BP1L) expression., Conclusion: Our findings indicated an oncogenic role of hsa&#95;circ&#95;0005939 in CRC, and it enhanced malignant phenotypes of CRC cells through miR-4693-3p/UHRF1BP1L axis. Our study may offer promising biomarkers and therapeutic targets for CRC., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background. Slow transit constipation (STC) is characterized by persistent, infrequent, or incomplete defecation. Systematic analyses of mRNA, lncRNA, and circRNA expression profiling in STC provide insights to understand the molecular mechanisms of STC pathogenesis. The present study is aimed at observing the interaction of mRNAs, lncRNAs, and circRNAs by RNA sequencing in vivo of STC. Methods. A rat model of STC was induced by loperamide. The expression profiles of both mRNAs and miRNAs were performed by RNA sequencing. Enrichment analyses of anomalous expressed mRNAs, lncRNAs, and circRNAs were performed in order to identify the related biological functions and pathologic pathways through the Gene Ontology (GO) database and Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Results. In total, 26435 mRNAs, 5703 lncRNAs, and 7708 circRNAs differentially expressed were identified between the two groups. The analyses of GO and KEGG show that (1) upregulated genes were enriched in a positive regulation of GTPase activity, cell migration, and protein binding and lipid binding and (2) GO annotations revealed that most trans-target mRNAs are involved in the regulation process of immune signal together with the proliferation and differentiation of immune cells. Additionally, the protein-protein interaction (PPI) network of differentially expressed (DE) mRNAs was constructed. Interestingly, all of the core lncRNAs and their coexpression mRNAs in this network are downregulated. Moreover, downregulated circRNAs have a set of target mRNAs related to immunoreaction, which was consistent with the overall tendency. Conclusion. Our investigation enriches the STC transcriptome database and provides a preliminary exploration of novel candidate genes and avenues expression profiles in vivo. The dysregulation of mRNAs, lncRNAs, and circRNAs might contribute to the pathological processes during STC. [ABSTRACT FROM AUTHOR]

In recent years, an increasing number of circular RNAs (circRNAs) have been discovered in hepatocellular carcinoma (HCC). However, the functions of most circRNAs require further investigation. Here, we found that circBACH1 was significantly upregulated in HCC tissues and that high circBACH1 levels were closely associated with poor prognosis. In addition, circBACH1 could promote HCC growth by accelerating cell cycle progression in vitro and in vivo. We next investigated the cellular and molecular mechanisms and discovered that circBACH1 inhibited p27 translation, which influenced cell cycle progression. Moreover, we revealed that circBACH1 could combine directly with HuR using RNA immunoprecipitation assays, pull-down assays, and electrophoretic mobility shift assays. The combination of these molecules facilitated HuR translocation from the nucleus to the cytoplasm according to the fluorescence in situ hybridization and immunofluorescence results. Finally, silencing HuR abrogated circBACH1's inhibition of p27 translation and abolished the circBACH1-induced effect on HCC proliferation. In sum, circBACH1 plays a significant role as an oncogene through the circBACH1/HuR/p27 axis in HCC development., (© 2020 Wiley Periodicals, Inc.)

Abstract: The accumulation of vascular smooth muscle cells (VSMCs) is considered to play important roles in atherosclerosis (AS) development and progression. Circ&#95;0002984 was found to be increased in oxidized low-density lipoprotein (ox-LDL) human VSMCs (HVSMCs). However, the function and mechanism of circ&#95;0002984 in VSMC dysfunction remain unknown. In this study, the expression of circ&#95;0002984, microRNA (miR)-379-5p, and fibroblast growth factor receptor substrate 2 (FRS2) was detected using quantitative real-time polymerase chain reaction and western blot. Cell proliferation, cell cycle, migration, and invasion were detected using Cell Counting Kit-8, flow cytometry, and transwell assays. The binding interaction between miR-379-5p and circ&#95;0002984 or FRS2 was confirmed by the dual-luciferase reporter assay. Collectively, this study found that circ&#95;0002984 was elevated in platelet-derived growth factor type bb (PDGF-bb)-induced HVSMCs. Circ&#95;0002984 knockdown abrogated PDGF-bb-induced proliferation, migration, and invasion in HVSMCs. Mechanistically, circ&#95;0002984 was confirmed to target miR-379-5p, and miR-379-5p upregulation reversed the protective effects of circ&#95;0002984 knockdown on PDGF-bb-induced HVSMCs. Besides, when FRS2 was a target of miR-379-5p, miR-379-5p restoration abolished PDGF-bb-evoked HVSMC dysfunction, which was attenuated by the overexpression of FRS2. Moreover, circ&#95;0002984 could regulate FRS2 expression through sponging miR-379-5p in HVSMCs. Collectively, these results demonstrated that circ&#95;0002984 promoted PDGF-bb-induced VSMC proliferation, migration, and invasion through the regulation of miR-379-5p/FRS2 axis, suggesting a new insight into the pathogenesis of AS and the potential application of circ&#95;0002984 in AS treatment., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

In view of the highly increased prevalence of papillary thyroid carcinoma (PTC) year by year, it is of great importance to explore new molecular targets for anticancer strategies. Emerging evidence indicates that circular RNAs (circRNAs), characterized by a closed-loop structure and high stability, play important roles in tumorigenesis and development of human cancer by regulating multiple complex biological processes, such as cellular proliferation, metastasis, and metabolism. A comprehensive understanding of the roles of circRNAs will facilitate the development of promising future therapeutic strategies for treating cancers, including PTC. In this paper, we review the profile of circRNA in PTC, its regulatory roles, and the pathological mechanism as well as their related clinical significance. In addition, challenges of this specific field are discussed. [ABSTRACT FROM AUTHOR]