Circular RNAs in laryngeal cancer.

Laryngeal cancer remains a significant global health concern, with poor prognosis for advanced-stage disease highlighting the need for novel diagnostic, prognostic, and therapeutic approaches. Circular RNAs (circRNAs), a class of covalently closed non-coding RNAs, have emerged as important regulators of gene expression and cellular processes in various cancers, including laryngeal cancer. This review summarizes the current understanding of circRNAs in laryngeal cancer, covering their biogenesis, regulatory mechanisms, and potential clinical applications. We explore the diverse functions of circRNAs, including their roles as miRNA sponges, protein interactors, and direct mRNA regulators, and their influence on key cellular processes such as proliferation, invasion, and metastasis. The review highlights promising circRNAs as diagnostic and prognostic biomarkers, as well as potential therapeutic targets. We also outline current strategies for circRNA modulation, including suppression techniques like RNA interference and CRISPR/Cas systems, and overexpression methods using vectors and synthetic circRNAs.

Hsa_circ_0079929 in lung adenocarcinoma and its biological implications in lung adenocarcinoma progression.

BACKGROUND: This report investigated the expression, prognostic and biological implications of hsa_circ_0079929 in lung adenocarcinoma, which was based on clinical and experimental data. METHODS: Patients with lung adenocarcinoma were screened and their clinical data and tissues (including cancerous tissues and adjacent normal tissues) were collected. The total RNA in tissues and cell lines was analyzed to obtained hsa_circ_0079929 level. The clinical significance was examined using the Chi-square test, Multi-variate Cox proportional hazards regression, and Kaplan-Meier curve. Cell malignant features were evaluated from three aspects (proliferation, migration, and invasion), detected by CCK-8 and Transwell methods. RESULTS: Hsa_circ_0079929 raised in expression level in lung adenocarcinoma. This upregulation of hsa_circ_0079929 was correlated with adverse clinical parameters and poor outcome in terms of overall survival, resulting in an independent prognostic purpose molecular for overall survival. Overexpression of hsa_circ_0079929 could contribute to cell proliferation/migration/invasion, whereas its knockdown could inhibit these malignant features. Hsa_circ_0079929 was a molecular decoy for miR-1184 in lung adenocarcinoma cells. CONCLUSIONS: Hsa_circ_0079929 could promote the malignant features of lung adenocarcinoma cells and may aid the follow up and therapeutic target discovery of lung adenocarcinoma.

[hsa_circ_0001776 targeting miR-1265 regulates the development of lung squamous cell carcinoma and clinical significance].

Objective: To further explore the role and mechanism of hsa_circ_0001776 and mir-1265 in lung squamous carcinoma by verifying the expression level of hsa_circ_0001776 in plasma, tissues, and cells of lung squamous carcinoma. Methods: Plasma was collected from patients with lung squamous carcinoma treated at Tangshan People's Hospital and healthy individuals from 2020 to 2022. Lung squamous carcinoma tissue microarrays purchased from Shanghai Xinchao Biotechnology Company in 2022. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa_circ_0001776 in lung squamous carcinoma plasma, tissues, and cells, and fluorescence in situ hybridization was used to verify the expression of hsa_circ_0001776 in lung squamous carcinoma. The localization of hsa_circ_0001776 in NCI-H1703 was verified by fluorescence in situ hybridization. The lung squamous carcinoma cells NCI-H1703 and NCI-H226 were cultured in vitro and divided into the circ-negative control (NC) group, hsa_circ_0001776 overexpression group, miR-NC group, miR-1265 mimic group, hsa_circ_0001776+miR-NC group, and hsa_circ_0001776+miR-1265 mimic group.The cell proliferation, motility and apoptosis were detected by the cell counting kit-8 (CCK-8) method, clone formation, Transwell invasion and migration, and scratch assay, and flow cytometry, respectively. The downstream of hsa_circ_0001776 was predicted by circular RNA interactome website, and the interaction between hsa_circ_0001776, miR-1265 was further determined by dual luciferase reporter gene assay, and nude mice subcutaneous tumorigenesis assay detected the growth of transplanted tumors. Results: Fluorescence in situ hybridization results showed that the fluorescence intensity of hsa_circ_0001776 in lung squamous carcinoma tissues was lower than that in paracancerous tissues, and the fluorescence intensity of miR-1265 in lung squamous carcinoma tissues was higher than that in paracancerous tissues (both P＜0.05). The expression level of hsa_circ_0001776 in the plasma of lung squamous carcinoma patients was lower than that in the plasma of healthy people, and the expression level of miR-1265 was higher than that in the plasma of healthy people (both P＜0.05). The expression levels of hsa_circ_0001776 in lung squamous carcinoma cells NCI-H1703, NCI-H226 and SK-MES-1 were lower than that in bronchial epithelial cells BEAS-2B (all P＜0.05), and the relative expression levels of miR-1265 in NCI-H1703 and NCI-H226 were higher than that in human bronchial epithelial cells BEAS -2B (all P＜0.05). The expression of hsa_circ_0001776 was correlated with age, lymph node metastasis, clinical stage, and tumor stage in patients with lung squamous carcinoma (all P＜0.05). Fluorescence in situ hybridization results showed that hsa_circ_0001776 was mainly expressed in the cytoplasm. The results of dual-luciferase reporter assay showed complementary binding of miR-1265 to hsa_circ_0001776. The absorbance values of the hsa_circ_0001776 overexpression group in NCI-H1703 and NCI-H226 cells were lower than that of the circ-NC group (P＜0.05). The number of cell clones in the hsa_circ_0001776 overexpressed group was (52±3) and (53±4), the number of migrating cells was (476±17) and (113±7), the number of invading cells was (100±2) and (184±2), and the cell migration rate was (25.00±4.36)% and (36.02±5.55)%, which were lower than those of the circ-NC group [(104±4) and (106±2), (783±29) and (517±16), (657±45) and (473±9), (48.95±8.69)% and (48.70±1.57)%, all P＜0.05]. The apoptosis rates in the overexpression hsa_circ_0001776 group were (24.77±2.303)% and (19.67±1.16)%, respectively, both higher than those in the circ-NC group [(11.83±1.15)% and (9.50±0.66)%, respectively, both P＜0.05]. MiR-1265 mimic group had a higher apoptotic rate in the NCI-H1703 and NCI-H226 than those of the miR-NC groups (P＜0.05). miR-1265 mimic group had (56±13) and (51±8) cell clones, (556±13) and (405±6) migrating cells, (486±6) and (359±7) invading cells, cell migration rates of (68.56±5.51)%, (81.74±8.04)%, were higher than those of miR-NC group [(31±4) and (21±8), (154±19) and (186±5), (227±6) and (176±7), (25.83±4.26)% and (53.12±4.14) %, all P＜0.05]. The apoptotic rates in the miR-1265 mimic group were (11.83±2.55)% and (17.50±1.05)%, respectively, which were lower than those in the miR-NC group [(32.67±4.44)% and (39.90±2.88)%, respectively, both P<0.05]. The absorbance values of NCI-H1703 and NCI-H226 in the overexpression of hsa_circ_0001776+miR-1265 mimic group were higher than those of the overexpression of hsa_circ_0001776+miR-NC group (P<0.05). The overexpression of hsa_circ_0001776+miR-1265 mimic group had (128±15) and (133±8) cell clones, (623±10) and (310±7) migrating cells, (643±16) and (420±7) invading cells, (66.39±4.46)% cell migration rate and (68.60±3.53)%, were higher than those of the hsa_circ_0001776+miR-NC group [(86±7) and (80±16), (380±11) and (115±5), (152±7) and (94±4), respectively, (31.41±5.91)% and (30.94±0.67)%, all P＜0.05]. The apoptotic rates in the overexpression of hsa_circ_0001776+miR-1265 mimic group were (19.27±0.15)% and (11.53±0.75)%, respectively, both lower than those in the overexpression of hsa_circ_0001776+miR-NC group [(27.77±1.29)% and (18.43±0.71)%, both P＜0.05]. The results of the subcutaneous tumorigenesis assay in nude mice showed that the volume of tumors in the overexpression of hsa_circ_0001776 group was lower than that in the circ-NC group (P＜0.05). Conclusion: hsa_circ_0001776 is downregulated in lung squamous cell carcinoma, and hsa_circ_0001776 can inhibit the development of lung squamous cell carcinoma by targeting miR-1265.

Circ_0025373 inhibits carbon black nanoparticles-induced malignant transformation of human bronchial epithelial cells by affecting DNA damage through binding to MSH2.

Carbon black nanoparticles (CBNPs) have been demonstrated to induce DNA damage in epithelial cells. However, the potential of the damage to initiate carcinogenesis and the underlying mechanism remain poorly understood. Therefore, we constructed an in vitro model of malignant transformation of human bronchial epithelial cells (16HBE-T) by treating 40 µg/mL CBNPs for 120 passages. We observed tumor-like transformation and sustained DNA damage. Using transcriptome sequencing and RIP-seq, we identified the overexpression of the critical DNA mismatch repair genes MutS homolog 2 (MSH2) and its related circular RNA, circ_0025373, in the 16HBE-T cells. Mechanistically, circ_0025373 was found to inhibit DNA damage by binding to MSH2, thereby modifying its expression and influencing its nuclear and cytoplasmic distribution, which lead to inhibition of CBNP-induced malignant transformation of human bronchial epithelial cells. Our findings provide novel evidence on the carcinogenicity of CBNPs, and offer biological insights into the potential epigenetic regulation and potential therapeutic targets for lung carcinogenesis.

[Research Progress of Circular RNA CircHIPK3 in Non-small Cell Lung Cancer].

Lung cancer ranks among the most prevalent and deadliest malignancies worldwide. Despite significant strides in targeted therapies and immunotherapy for lung cancer, curing the disease remains a highly prioritized issue. Circular RNAs (circRNAs), recently discovered RNA molecules characterized by covalently closed loop structures, possess features such as structural stability, sequence conservation, and disease-specific expression. Cutting-edge medical research has linked circRNA dysregulation to the progression of various cancers. Among these, circular RNA HIPK3 (circHIPK3), an oncogenic gene primarily derived from the second exon of the HIPK3 gene, has emerged as a focal point of investigation. Increasing evidences suggest that circHIPK3 is involved in the development of non-small cell lung cancer (NSCLC) and other malignancies. Aberrant expression of circHIPK3 is closely associated with the disease mechanisms, diagnosis, treatment, and prognosis of NSCLC. This review discusses the latest research advancements on circHIPK3 in NSCLC, aiming to promote precise diagnosis and treatment of lung cancer.
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Whole transcriptome landscape in HAPE under the stress of environment at high altitudes: new insights into the mechanisms of hypobaric hypoxia tolerance.

Background: High altitude pulmonary edema (HAPE) is an idiopathic, noncardiogenic form of pulmonary edema that occurs at high altitudes. It is characterized by a severe clinical course and carries a significant mortality risk. Despite its clinical relevance, the molecular mechanisms underlying HAPE are not well understood. Methods: We conducted whole-transcriptome RNA sequencing on blood samples from 6 pairs of HAPE patients and healthy controls to identify differentially expressed (DE) mRNAs, miRNAs, circRNAs, lncRNAs, along with alternative splicing (AS) events, gene fusions, and novel transcripts. To explore the regulatory dynamics, we constructed ceRNA networks and analyzed immune cell infiltration patterns, further annotating the biological functions of these transcripts. For empirical validation, we selected five circRNAs from the ceRNA network and conducted RT-qPCR on 50 paired samples. Additionally, we assessed the correlations between circRNA expression levels and clinical data to evaluate their diagnostic potential. Results: We observed 2,023 differentially expressed mRNAs (DEmRNAs), 84 DEmiRNAs, 200 DEcircRNAs, and 3,573 DElncRNAs. A total of 139 'A3SS' events, 103 'A5SS' events, 545 'MXE' events, 14 'RI' events, and 1,482 'SE' events were identified in the AS events analysis between the two groups. Two ceRNA networks were constructed. T cells, follicular helper, and Macrophages M1 cells exhibited the strongest positive correlation (R=0.82), while naive B cells and memory B cells demonstrated the strongest negative correlation (R=-0.62). In total, the expression of three circRNAs was significantly different in a larger cohort. Hsa_circ_0058497, hsa_circ_0081006, and hsa_circ_0083220 demonstrated consistent with the RNA sequencing results. These three circRNAs strongly correlate with clinical indicators and exhibit potential as diagnostic biomarkers. Finally, we verified five genes (CXCR4, HSD17B2, ANGPTL4, TIMP3, N4BP3) that were differentially expressed in endothelial cells under normoxia and hypoxia through bioinformatics and RT-qPCR analyses. Conclusion: This study elucidates the differential expression of coding and non-coding RNAs (ncRNAs) in HAPE, identifies new transcripts and genes, and enhances our understanding of the transcriptional characteristics of HAPE. Moreover, it highlights the potential role of circRNAs in advancing the diagnosis and treatment of HAPE.

CircSEC24B activates autophagy and induces chemoresistance of colorectal cancer via OTUB1-mediated deubiquitination of SRPX2.

Circular RNAs (circRNAs) are a type of regulatory RNA that feature covalently closed single-stranded loops. Evidence suggested that circRNAs play important roles in the progression and development of various cancers. However, the impact of circRNA on autophagy-mediated progression of colorectal cancer (CRC) remains unclear. The objective of this project was to investigate the influence of circSEC24B on autophagy and its underlying mechanisms in CRC. To validate the presence and circular structure of circSEC24B in CRC cells and tissues, PCR and Sanger sequencing techniques were employed. Drug resistance and invasive phenotype of CRC cells were evaluated using CCK8, transwell, and Edu assays. Gain- and loss-of-function experiments were conducted to assess the effects of circSEC24B and its protein partner on the growth, invasion, and metastasis of CRC cells in vitro and in vivo. Interactions between circSEC24B, OTUB1, and SRPX2 were analyzed through immunofluorescence, RNA-pulldown, and RIP assays. Mass spectrometry analysis was used to identify potential binding proteins of circRNA in CRC cells. Vectors were constructed to investigate the specific structural domain of the deubiquitinating enzyme OTUB1 that binds to circSEC24B. Results showed that circSEC24B expression was increased in CRC tissues and cell lines, and it enhanced CRC cell proliferation and autophagy levels. Mechanistically, circSEC24B promoted CRC cell proliferation by regulating the protein stability of SRPX2. Specifically, circSEC24B acted as a scaffold, facilitating the binding of OTUB1 to SRPX2 and thereby enhancing its protein stability. Additionally, evidence suggested that OTUB1 regulated SRPX2 expression through an acetylation-dependent mechanism. In conclusion, this study demonstrated that circSEC24B activated autophagy and induced chemoresistance in CRC by promoting the deubiquitination of SRPX2, mediated by the deubiquitinating enzyme OTUB1.

Circular RNA circRNA_100349 functions as a miR-218-5p sponge for suppressing the cell proliferation of gastric cancer via regulation of IGF2 expression.

BACKGROUND: Circular RNAs (circRNAs) hold critical importance due to their notable function in developing Gastric Cancer (GC), which is a malignancy with the third most frequent occurrence worldwide. The aim of this study was to see if circRNA_0044516 would control GC cell proliferation and establish more effective therapeutic strategies. METHODS: In GC tissues or cells, quantitative Real­Time Polymerase Chain Reaction (qRT-PCR) was employed for the detection of the expression of circRNA_100349, Insulin-like Growth Factor II (IGF2), and miR-218-5p. CCK-8 assays were employed to gauge the proliferation of cells. A luciferase reporter was employed to establish the relationship of circRNA_100349 or IGF2 with miR-218-5p. RESULTS: CircRNA_100349 was observed to undergo upregulation in GC cell lines along with tissues. GC cell proliferation was prevented by downregulating circRNA_100349. MiR-149 was targeted by CircRNA_100349, and its downregulation increased the amount of miR-218-5p in GC cells. Simultaneously silencing circRNA_100349 decreased IGF2 expression via miR-218-5p, and thus suppressed GC cell proliferation. Furthermore, in nude mice, circRNA_100349 knockdown prevented the tumor development of GC cells. CONCLUSIONS: The findings furnished evidence of the critical involvement of circRNA_100349 in GC and that its downregulation impedes GC cell proliferation via the miR-218-5p/IGF2 axis.

Helicobacter pylori induce circ_0046854 to regulate microRNA-511-3p/CSF1 axis and enhance the resistance of gastric cancer to cisplatin.

Helicobacter pylori (HP) is considered a major risk factor for gastric cancer (GC) and during this process, cytotoxin­associated gene A (CagA) plays in essence. The study mainly focused on the molecular mechanism of circular RNA 0046854 (circ_0046854) in HP-induced GC. Clinically, 56 cases of GC and normal tissues were collected, and the GC tissues were divided into HP-negative GC tissues (HP-) and 33 HP-positive GC tissues (HP+). Tissue expression of circ_0046854, microRNA (miR)-511-3p and colony-stimulating factor 1 (CSF1) was tested. BGC-823/Cisplatin (DDP) resistant strain was induced and cell growth and DDP resistance were detected after HP infection. In vivo experiments were performed using a mouse xenograft model. The relationship between circ_0046854, miR-511-3p and CSF1 was confirmed. GC tissues especially HP+ cancer tissues expressed high circ_0046854 and CSF1 and low miR-511-3p. HP-induced circ_0046854 expression in GC cells through CagA. Inhibition of circ_0046854 or miR-511-3p elevation inhibited the growth and DDP resistance in GC cells. Circ_0046854 acted as a sponge for miR-511-3p, which targeted CSF1. Restoring CSF1 could abolish the inhibitory effect of miR-511-3p overexpression on CagA+ HP-induced GC progression in vitro. Circ_0046854 silencing repressed tumor growth and aggrandized the inhibiting effects of DDP on tumorigenesis in vivo. Circ_0046854/miR-511-3p/CSF1 axis may be involved in the development of HP-induced GC, thus providing new ideas for studying the mechanism of HP-related gastric diseases.

CircRNA_001373 promotes liver fibrosis by regulating autophagy activation in hepatic stellate cells via the miR-142a-5p/Becn1 axis.

The purpose of this study was to investigate the regulatory role and underlying mechanisms of circRNA_001373 in the hepatic stellate cell (HSC) activation. Quantitative real-time polymerase chain reaction was used to detect the expression of circRNA_001373, miR-142a-5p and Becn1. The viability of JS-1 cells was measured by Cell Counting Kit-8. The targeting relationship between miR-142a-5p and CircRNA_001373, as well as between miR-142a-5p and Becn1 was predicted using CircInteractome and TargetScan databases, respectively, and validated by dual-luciferase reporter assay. Western blot was utilized to determine the expression levels of proteins related to autophagy and the activation if HSCs in JS-1 cells. After activation by platelet-derived growth factor-BB, an increase was observed in the expression of collagen I and α-smooth muscle actin proteins. The expression of CircRNA_001373 was up-regulated in the activated HSCs. Knockdown of CircRNA_001373 significantly inhibited cell viability and activation of JS-1 cells, as well as autophagy in the activated HSCs. CircRNA_001373 could sponge miR-142a-5p in the activated HSCs, which in turn elevated the Becn1 expression. Concurrent knockdown of both CircRNA_001373 and miR-142a-5p reversed the inhibitory effects of the knockdown of CircRNA_001373 alone on cell viability and autophagy in activated JS-1 cells. CircRNA_ 001373 promotes cell viability and autophagy as well as the activation of JS-1 cells by regulating the miR-142a-5p/Becn1 axis.

Dual role of exosomal circCMTM3 derived from GSCs in impeding degradation and promoting phosphorylation of STAT5A to facilitate vasculogenic mimicry formation in glioblastoma.

Background: Glioblastoma (GBM) is characterized by abundant neovascularization as an essential hallmark. Vasculogenic mimicry (VM) is a predominant pattern of GBM neovascularization. However, the biological functions of circRNAs prompting VM formation in GBM remains unclarified. Methods: The circular RNA circCMTM3 was identified through high-throughput sequencing and bioinformatics analysis. The expression of circCMTM3 in exosomes in glioma tissues and cells was verified via RT-qPCR and FISH. In vitro and in vivo assays, such as EdU, MTS, Transwell, and tube formation assays were performed to investigate functional roles of circCMTM3. Meanwhile, in situ tumorigenesis assay were implemented to explore the influences of circCMTM3 on the GBM progression. Additionally, RNA pull-down, RIP, ChIP, and dual-luciferase reporter gene assays were executed to confirm the underlying regulation mechanism of circCMTM3. Results: CircCMTM3, as a novel circular RNA, was packaged into exosomes derived from glioblastoma stem cells (GSCs), which facilitates the phenotypic transition of differentiated glioma cells (DGCs) to VM. Mechanistically, exosomal circCMTM3 is internalized by DGCs and disrupt the ubiquitination degradation of STAT5A and STAT5B by E3 ubiquitin ligase CNOT4. Additionally, through molecular scaffold function of circCMTM3, STAT5A is activated and triggers transcriptional regulation of target genes including the pro-vasculogenic factor CHI3L2 and the RNA-binding protein SRSF1. Subsequently, circCMTM3/STAT5A/SRSF1 positive feedback loop sustainably enhances VM formation and accelerates tumor progression in GBM. Conclusion: Exosomal circCMTM3 possessing growth factor-mimetic property activates the JAK2/STAT5A pathway via non-canonical manner, and promotes VM formation in GBM. The molecular communications between GSCs and DGCs offers a therapeutic strategy for targeting the neovascularization of GBM.

Exploring the influence of non-coding RNAs on NF-κB signaling pathway regulation in ulcerative colitis.

The gastrointestinal tract is chronically inflamed in ulcerative colitis (UC), which has a complicated etiology involving immunological, environmental, and genetic factors. The inflammatory response that is typical of UC is significantly regulated via the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway. Latest research has displayed that NF-κB signaling is controlled by three main types of non-coding RNAs (ncRNAs): circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and microRNAs (miRNAs). These ncRNAs can change the expression of key genes within the NF-κB pathway by acting as molecular sponges, transcriptional regulators, and epigenetic modifiers. This review synthesizes current knowledge on the functions by which ncRNAs modulate NF-κB signaling in UC, discusses their potential as biomarkers for disease prognosis and diagnosis, and explores their therapeutic potential. Understanding the intricate interactions between ncRNAs and NF-κB signaling may provide novel insights into UC pathogenesis and targeted therapeutic strategies.

Circular RNA HMGCS1 sponges MIR4521 to aggravate type 2 diabetes-induced vascular endothelial dysfunction.

Noncoding RNA plays a pivotal role as novel regulators of endothelial cell function. Type 2 diabetes, acknowledged as a primary contributor to cardiovascular diseases, plays a vital role in vascular endothelial cell dysfunction due to induced abnormalities of glucolipid metabolism and oxidative stress. In this study, aberrant expression levels of circHMGCS1 and MIR4521 were observed in diabetes-induced human umbilical vein endothelial cell dysfunction. Persistent inhibition of MIR4521 accelerated development and exacerbated vascular endothelial dysfunction in diabetic mice. Mechanistically, circHMGCS1 upregulated arginase 1 by sponging MIR4521, leading to decrease in vascular nitric oxide secretion and inhibition of endothelial nitric oxide synthase activity, and an increase in the expression of adhesion molecules and generation of cellular reactive oxygen species, reduced vasodilation and accelerated the impairment of vascular endothelial function. Collectively, these findings illuminate the physiological role and interacting mechanisms of circHMGCS1 and MIR4521 in diabetes-induced cardiovascular diseases, suggesting that modulating the expression of circHMGCS1 and MIR4521 could serve as a potential strategy to prevent diabetes-associated cardiovascular diseases. Furthermore, our findings provide a novel technical avenue for unraveling ncRNAs regulatory roles of ncRNAs in diabetes and its associated complications.

Circ_0005397 inhibits ferroptosis of pancreatic cancer cells by up-regulating PCBP2 through KAT6A/H3K9Ac.

Pancreatic cancer is a highly aggressive and lethal carcinoma. Circular RNAs (circRNAs) serve key regulatory functions in pancreatic cancer. Ferroptosis was induced by erastin treatment and analyzed by examining malondialdehyde (MDA), iron, Fe2+ and glutathione (GSH). C11-BODIPY 581/591 was used to stain cells for analyzing lipid peroxidation. RNA immunoprecipitation, pull-down and chromatin immunoprecipitation assays were applied to evaluate intermolecular interaction. Mice received subcutaneous injection of pancreatic cancer cells as a model of subcutaneous tumor for in vivo tests. Circ_0005397 was abundantly expressed in pancreatic cancer, and its upregulation was associated with low survival of patients with pancreatic cancer. Circ_0005397 expression was induced by EIF4A3. PCBP2 was highly expressed in pancreatic cancer, and circ_0005397 and PCBP2 were positively correlated in patients with pancreatic cancer. Circ_0005397 knockdown sensitized pancreatic carcinoma cells to ferroptosis via downregulating PCBP2. Circ_0005397 promoted PCBP2 transcription via facilitating the binding of KAT6A and H3K9ac to PCBP2 promoter. Silencing of circ_0005397 reduced tumor growth by enhancing erastin-induced ferroptosis in vivo. EIF4A3-induced circ_0005397 inhibited erastin-induced ferroptosis in pancreatic cancer by promoting PCBP2 expression through KAT6A and H3K9ac.

Abnormal expression of circ_0013958 in patients with acute myocardial infarction (AMI) and its influence on prognosis.

OBJECTIVE: The purpose of this study was to investigate the diagnostic value of circ_0013958 in acute myocardial infarction (AMI) patients and its influence on the prognosis of AMI patients. METHODS: The GSE160717 dataset was downloaded from the NCBI database and differentially expressed genes were analyzed between the control group and the AMI group. The up-regulated genes included circ_0013958. The expression of circ_0013958 in both groups was further verified by RT-qPCR. The Receiver Operating Characteristic curve was used to evaluate the diagnostic value of circ_0013958 in AMI. Pearson correlation analysis was used to examine the correlation between circ_0013958 levles and biochemical indicators. Binary logistic regression was used to analyze the risk factors affecting the occurrence of AMI. Prognostic analysis was performed using COX regression analysis and the Kaplan-Meier Curve. RESULTS: Compared to the control group, the level of circ_0013958 in AMI patients increased. Circ_0013958 can effectively distinguish AMI patients from non-AMI patients. Circ_0013958 levels were positively correlated with cTnI, LDH, CRP and TC levels. The elevated level of circ_0013958 was an independent risk factor for the occurrence of AMI. Higher circ_0013958 levels were also associated with the occurrence of major adverse cardiac events (MACEs) in AMI patients. Additionally, elevated circ_0013958 levels reduced the survival probability of AMI patients. CONCLUSION: Circ_0013958 levels were up-regulated in AMI patients. It can be used as a diagnosis biomarker for AMI. The level of circ_0013958 was correlated with the disease severity and was an independent risk factor for the occurrence of AMI. Elevated circ_0013958 levels were associated with poor prognosis in AMI patients.

Circular RNA_0003489 reflects unfavorable treatment response and shortened survival in newly diagnosed multiple myeloma patients who receive bortezomib-based induction therapy.

OBJECTIVES: Circular RNA_0003489 (Circ_0003489) promotes multiple myeloma (MM) progression and bortezomib resistance in MM cells, while its potential as a biomarker in newly diagnosed MM (NDMM) patients is unclear. Thus, this study aimed to investigate the association of circ_0003489 expression with treatment response and survival in NDMM patients who received bortezomib-based induction therapy. METHODS: Bone marrow (BM) specimens from 85 NDMM patients at diagnosis or before treatment and from 15 donor controls during BM examination were retrieved in this retrospective study. Circ_0003489 derived from BM plasma cells was detected by reverse transcription-quantitative polymerase chain reaction and cut by quartile and median for further analysis. RESULTS: Circ_0003489 expression was increased in NDMM patients versus donor controls (P < 0.001). Circ_0003489 quartile was positively correlated with BM plasma cells (P = 0.040), international staging system (ISS) stage (P = 0.007), the revision of ISS stage (P = 0.003), beta-2-microglobulin (P = 0.011), and lactate dehydrogenase (P = 0.042) in NDMM patients. Increased circ_0003489 quartile was linked with a lower possibility of achieving complete response (P = 0.020) and partial response or better (P = 0.041) in NDMM patients. Elevated circ_0003489 expression cut by quartile (P = 0.020) and cut by median (P = 0.006) were linked with decreased progression-free survival (PFS) in NDMM patients. Increased circ_0003489 expression cut by median was associated with shortened overall survival (OS) in NDMM patients (P = 0.038). Meanwhile, higher circ_0003489 quartile independently forecasted poorer PFS (hazard ratio = 1.342, P = 0.045), but not OS in NDMM patients. CONCLUSION: Circ_0003489 expression is increased and reflects unfavorable treatment response and survival in NDMM patients who receive bortezomib-based induction therapy.

Biogenesis of circRBM33 mediated by N6-methyladenosine and its function in abdominal aortic aneurysm.

This study aimed to explore whether m6A modification affects the biogenesis of circRBM33, which is involved in the progression of abdominal aortic aneurysm (AAA). For in vitro experiments, vascular smooth muscle cells (VSMCs) were treated with Ang II. MeRIP‒PCR was used to assess m6A modification of circRBM33. Gene expression was measured using RT‒qPCR and Western blotting. For in vivo experiments, a mouse model of AAA was established via Ang II infusion. HE, Sirius Red and TUNEL staining was performed to evaluate pathological changes and cell apoptosis in aortic vessels. The results showed that the m6A level of circRBM33 was abnormally increased in Ang II-induced VSMCs. In addition, METTL3 positively regulated circRBM33 expression. YTHDC1 deficiency decreased circRBM33 expression but had no effect on RBM33 mRNA expression. Notably, neither METTL3 nor YTHDC1 influenced the stability of circRBM33 or RBM33 mRNA. The interaction between circRBM33 and METTL3/YTHDC1 was verified by RIP analysis. Moreover, the Ang II-induced increase in circRBM33 expression was reversed by cycloleucine (an inhibitor of m6A methylation). Importantly, the m6A modification and expression of circRBM33 in the circRBM33-m6A-mut2-expressing VSMCs were not altered by METTL3 silencing. Mechanistically, METTL3/YTHDC1 modulates the biogenesis of circRBM33 in an m6A-dependent manner. In addition, circRBM33 knockdown alleviated AAA by reducing ECM degradation in the Ang II-infused mice. In conclusion, this study demonstrated that METTL3/YTHDC1-mediated m6A modification modulates the biogenesis of circRBM33 from exons of the RBM33 gene. Moreover, knockdown of circRBM33 alleviated AAA by reducing ECM degradation, which may provide a novel therapeutic strategy for treating AAA.

Postoperative Organ Dysfunction Risk Stratification Using Extracellular Vesicle-Derived circRNAs in Pediatric Congenital Heart Surgery.

Breakthroughs in surgical and medical techniques have significantly improved outcomes for children with congenital heart disease (CHD), but research continues to address the ongoing challenge of organ dysfunction after surgery, particularly in neonates and infants. Our study explored circular RNAs (circRNAs) within plasma-derived extracellular vesicles (EVs) in neonates and infants undergoing CHD surgery. Post-surgery EV circRNAs showed dramatic expression changes between organ dysfunction (OD) and control groups. Tissue injury-related pathways were consistent across pre- and post-surgery in OD. The top two significant predicted tissue sources of these circRNAs originated from the respiratory system, aligning with the fact that all patients in the OD arm experienced respiratory dysfunction. Five of these circRNAs, namely circ-CELSR1, circ-PLXNA1, circ-OBSL1, circ-DAB2IP, and circ-KANK1, significantly correlated with PELOD (Pediatric Logistic Organ Dysfunction) score and demonstrated high performance (AUC = 0.95), supporting the potential of circRNAs as prognostic markers. These findings pave the way for EV circRNAs as promising tools for managing post-surgical organ dysfunction and potentially guiding therapeutic strategies in children with CHD.

A systematic analysis of circRNAs in subnuclear compartments.

CircRNAs are an important class of RNAs with diverse cellular functions in human physiology and disease. A thorough knowledge of circRNAs including their biogenesis and subcellular distribution is important to understand their roles in a wide variety of processes. However, the analysis of circRNAs from total RNA sequencing data remains challenging. Therefore, we developed Calcifer, a versatile workflow for circRNA annotation. Using Calcifer, we analysed APEX-Seq data to compare circRNA occurrence between whole cells, nucleus and subnuclear compartments. We generally find that circRNAs show higher abundance in whole cells compared to nuclear samples, consistent with their accumulation in the cytoplasm. The notable exception is the single-exon circRNA circCANX(9), which is unexpectedly enriched in the nucleus. In addition, we observe that circFIRRE prevails over the linear lncRNA FIRRE in both the cytoplasm and the nucleus. Zooming in on the subnuclear compartments, we show that circRNAs are strongly depleted from nuclear speckles, indicating that excess splicing factors in this compartment counteract back-splicing. Our results thereby provide valuable insights into the subnuclear distribution of circRNAs. Regarding circRNA function, we surprisingly find that the majority of all detected circRNAs possess complete open reading frames with potential for cap-independent translation. Overall, we show that Calcifer is an easy-to-use, versatile and sustainable workflow for the annotation of circRNAs which expands the repertoire of circRNA tools and allows to gain new insights into circRNA distribution and function.

CircBIRC6 affects prostate cancer progression by regulating miR-574-5p and DNAJB1.

BACKGROUND: Prostate cancer (PCa) is among the three main types of cancer. Although prostate-specific antigen (PSA) is routinely tested, it has disadvantages, such as poor prognostic ability. Therefore, finding more PCa markers and therapeutic targets remains a subject of study. CircRNAs have been found to have regulatory roles in various diseases, such as diabetes, Central Nervous System (CNS) neuropathy, etc. where their application in cancer is even more valuable. Therefore, this paper aims to search for differentially expressed circRNAs in PCa and find downstream targeting pathways related to autophagy. METHOD: By detecting the expression of circRNA in the samples, hsa_circ_0119816 was finally identified as the research target. The properties of circRNA were verified by RNase R, actinomycin D, and fluorescence in situ hybridization (FISH). The downstream target miRNAs and target proteins were predicted by an online database, and the targeting relationship was verified using dual luciferase and RNA Immunoprecipitation. The effects of circRNAs and their downstream signalling pathways on prostate cancer cell proliferation, migration, EMT and autophagy were examined by CCK-8, Transwell, immunofluorescence and Western blotting. RESULTS: CircBIRC6 is highly expressed in prostate cancer samples. Knockdown of its expression inhibits cell proliferation, invasion, EMT and autophagy and promotes apoptosis. CircBIRC6/miRNA-574-5p/DNAJB1 is a molecular axis that regulates prostate cancer cells.