Circular RNA circCDK13 suppresses cell proliferation, migration and invasion by modulating the JAK/STAT and PI3K/AKT pathways in liver cancer

hsa_circ_0000285 sponging miR-582-3p promotes neuroblastoma progression by regulating the Wnt/β-catenin signaling pathway

Circular RNA has been reported to play a key role in neuroblastoma (NB); however, the role of circ_0000285 in NB remains unclear. The aim of this study was to elucidate the role of circ_0000285 in NB. We studied the expression patterns of miR-582-3p and circ_0000285 in NB tissues and cells using real-time quantitative polymerase chain reaction. The expression of proteins associated with apoptosis (Bax and Bcl-2) and the proteins associated with Wnt/β-catenin (Wnt, p-Gsk-3β, Gsk-3β, β-catenin, and C-myc) were quantified by western blotting. In vivo animal models were prepared for the functional verification of circ_0000285 on tumor growth. The potential binding of circ_0000285 to miR-582-3p was ascertained using dual-luciferase reporter and RNA-binding protein immunoprecipitation experiments. Noticeable upregulation of circ_0000285 expression was observed in NB tumor samples and cell lines. In vivo and in vitro experiments indicated that the absence of circ_0000285 repressed NB cell proliferation and migration, provoked apoptosis, and impaired the activity of Wnt/β-catenin signaling. miR-582-3p is targeted by circ_0000285 and is poorly expressed in NB cells. The additional repression of miR-582-3p in NB cells after circ_0000285 silencing largely recovered circ_0000285 silencing-suppressed NB cell proliferation and migration and enhanced apoptosis. The absence of miR-582-3p restored Wnt/β-catenin signaling activity impaired by the knockdown of circ_0000285. circ_0000285 functions as an miR-582-3p sponge to strengthen Wnt/β-catenin signaling activity, thus exacerbating NB development.

Circular RNAs in hepatocellular carcinoma: biogenesis, function, and pathology

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death worldwide. Both genetic and environmental factors through a multitude of underlying molecular mechanisms participate in the pathogenesis of HCC. Recently, numerous studies have shown that circular RNAs (circRNAs), an emerging class of non-coding RNAs characterized by the presence of covalent bonds linking 3' and 5' ends, play an important role in the initiation and progression of cancers, including HCC. In this review, we outline the current status of the field of circRNAs, with an emphasis on the functions and mechanisms of circRNAs in HCC and its microenvironment. We also summarize and discuss recent advances of circRNAs as biomarkers and therapeutic targets. These efforts are anticipated to throw new insights into future perspectives about circRNAs in basic, translational and clinical research, eventually advancing the diagnosis, prevention and treatment of HCC.

Janus Kinase-Signal Transducer and Activator of Transcription Inhibitors for the Treatment and Management of Cancer

According to the World Health Organization (WHO), cancer is the second-highest cause of mortality worldwide, killing nearly 9.6 million people annually. Despite the advances in diagnosis and treatment during the last couple of decades, it remains a serious concern due to the limitations of currently available cancer management strategies. Therefore, alternative strategies are highly required to overcome these glitches. In addition, many etiological factors such as environmental and genetic factors initiate the activation of the Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) pathway. This aberrant activation of the JAK-STAT pathway has been reported in various disease states, including inflammatory conditions, hematologic malignancies, and cancer. For instance, many patients with myeloproliferative neoplasms carry the acquired gain-of-function JAK2 V617F somatic mutation. This knowledge has dramatically improved our understanding of pathogenesis and has facilitated the development of therapeutics capable of suppressing the constitutive activation of the JAK-STAT pathway. Our aim is not to be expansive but to highlight emerging ideas towards preventive therapy in a modern view of JAK-STAT inhibitors. A series of agents with different specificities against different members of the JAK family of proteins is currently undergoing evaluation in clinical trials. Here we give a summary of how JAK-STAT inhibitors function and a detailed review of current clinical drugs for managing cancer as a new therapeutic approach.

Circular RNA as a Novel Biomarker and Therapeutic Target for HCC

Circular RNA (circRNA) is a kind of endogenous non-coding RNA (ncRNA), which is produced by the reverse splicing of precursor mRNA (pre mRNA). It is widely expressed in a variety of biological cells. Due to the special formation mode, circRNA does not have a 5′ terminal cap and 3′ poly (A) tail structure. Compared with linear RNA, circRNA is more stable to exonuclease and ribonuclease. In addition, circRNA is structurally conserved, has a stable sequence and is tissue-specific. With the development of high-throughput sequencing and bioinformatics technology, more and more circRNAs have been found. CircRNA plays an important pathophysiological role in the occurrence and development of alcoholic liver injury (ALI), hepatic fibrosis (HF), hepatocellular carcinoma (HCC), and other liver diseases. Our group has been committed to the research of liver disease diagnosis and treatment targets. We review the function and mechanism of circRNA in ALI, HF and HCC, expecting to provide new ideas for the diagnosis, treatment, and prognosis of liver diseases.

hMSCs-derived exosome circCDK13 inhibits liver fibrosis by regulating the expression of MFGE8 through miR-17-5p/KAT2B

OBJECTIVE

To investigate the effects of human bone marrow mesenchymal stem cells (hMSCs)-derived exosome circCDK13 on liver fibrosis and its mechanism.

METHODS

Exosomes derived from hMSCs were extracted and identified by flow cytometry and osteogenic and adipogenic induction, and the expressions of marker proteins on the surface of exosomes were detected by western blot. Cell proliferation was measured by CCK8 assay, the expression of active markers of HSCs by immunofluorescence, and the expressions of fibrosis-related factors by western blot. A mouse model of liver fibrosis was established by intraperitoneal injection of thioacetamide (TAA). Fibrosis was detected by HE staining, Masson staining, and Sirius red staining. Western blot was utilized to test the expressions of PI3K/AKT and NF-κB pathway related proteins, dual-luciferase reporter assay and RIP assay to validate the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B, and ChIP to validate the effect of KAT2B on H3 acetylation and MFGE8 transcription.

RESULTS

hMSCs-derived exosomes inhibited liver fibrosis mainly through circCDK13. Dual-luciferase reporter assay and RIP assay demonstrated the binding between circCDK13 and miR-17-5p as well as between miR-17-5p and KAT2B. Further experimental results indicated that circCDK13 mediated liver fibrosis by regulating the miR-17-5p/KAT2B axis, and KAT2B promoted MFGE8 transcription by H3 acetylation. Exo-circCDK13 inhibited PI3K/AKT and NF-κB signaling pathways activation through regulating the miR-17-5p/KAT2B axis.

CONCLUSION

hMSCs-derived exosome circCDK13 inhibited liver fibrosis by regulating the expression of MFGE8 through miR-17-5p/KAT2B axis.

Valsartan Regulates PI3K/AKT Pathways through lncRNA GASL1 to Improve Isoproterenol-Induced Heart Failure

Objective

This study is aimed at determining the expression and function of the GASL1 and PI3K/AKT pathways in isoproterenol- (ISO-) induced heart failure (HF). To determine the moderating effect of valsartan (VAL) on the progression of ISO-induced HF and to elucidate the related mechanism.

Materials and Methods

First, in in vivo experiment, we examined the effect of VAL on cardiac function in rats with ISO-induced HF. Similarly, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to detect the effect of VAL on ISO-treated rat primary cardiomyocytes. Then, si-GASL1-transfected primary cardiomyocytes were constructed and Ad-si-GASL1 was injected through rat tail vein to achieve the effect of lowering GASL1 expression, so as to investigate the role of GASL1 in VAL's treatment of ISO-induced HF.

Results

In ISO-induced HF rat models, the GASL1 decreased while PI3K and p-AKT expressions were abnormally elevated and cardiac function deteriorated, and VAL was able to reverse these changes. In primary cardiomyocytes, ISO induces apoptosis of cardiomyocytes, and expression of GASL1 decreased while PI3K and p-AKT were abnormally elevated, which can be reversed by VAL. The transfection of primary cardiomyocytes with si-GASL1 confirmed that GASL1 affected the expression of PI3K, p-AKT, and the apoptosis of primary cardiomyocytes. Rat myocardium injected with Ad-si-GASL1 was found to aggravate the cardiac function improved by VAL.

Conclusions

This study was the first to confirm that VAL improves ISO-induced HF by regulating the PI3K/AKT pathway through GASL1. And this study demonstrated a significant correlation between HF, VAL, GASL1, and the PI3K/AKT pathway.

Crosstalk between circRNAs and the PI3K/AKT signaling pathway in cancer progression

Circular RNAs (circRNAs), covalently closed noncoding RNAs, are widely expressed in eukaryotes and viruses. They can function by regulating target gene expression, linear RNA transcription and protein generation. The phosphoinositide 3-kinase (PI3K)/AKT signaling pathway plays key roles in many biological and cellular processes, such as cell proliferation, growth, invasion, migration, and angiogenesis. It also plays a pivotal role in cancer progression. Emerging data suggest that the circRNA/PI3K/AKT axis modulates the expression of cancer-associated genes and thus regulates tumor progression. Aberrant regulation of the expression of circRNAs in the circRNA/PI3K/AKT axis is significantly associated with clinicopathological characteristics and plays an important role in the regulation of biological functions. In this review, we summarized the expression and biological functions of PI3K-AKT-related circRNAs in vitro and in vivo and assessed their associations with clinicopathological characteristics. We also further discussed the important role of circRNAs in the diagnosis, prognostication, and treatment of cancers.

Circular RNA expression profiles in human bronchial epithelial cells treated with beryllium sulfate

Circular RNAs (circRNAs), is a novel type of endogenous non-coding RNAs (ncRNAs) participated in the pathogenesis of many diseases. Beryllium is one of the carcinogenesis elements. However, the mechanism and function of circRNAs in human bronchial epithelial cells (16HBE) induced by beryllium sulfate (BeSO₄) was rarely reported. Therefore, the high-throughput RNA sequencing analysis was performed to detect the circRNA profiles between control groups and BeSO₄-induced groups. Furthermore, circRNA-miRNA-mRNA network, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and PPI network analysis were used for bioinformatics analysis. CircRNA sequencing analysis revealed that 36 circRNAs were up-regulated and 35 circRNAs were down-regulated in the BeSO₄-exposed groups. The selected circRNAs were verified by real-time fluorescent quantitative PCR (qRT-PCR). Hsa_circ_0004214 and hsa_circ_0003586 were validated to be up-regulated, hsa_circ_0047958, hsa_circ_0001944, and hsa_circ_0008982 were down-regulated. The circRNA-miRNA-mRNA network annotated the key signaling pathway including cellular senescence, TNF signaling pathway, NF-kappa B signaling pathway, HIF-1 signaling pathway, and Hippo signaling pathway. The PPI network indicated the most circRNAs might participate in the BeSO₄ toxicity by acting as a sponge for the miR-663b through JAK-STAT signaling pathway. In summary, our study suggests that circRNAs may play roles in the mechanism of beryllium toxicity.

Determination of Genetic and Epigenetic Modifications-Related Prognostic Biomarkers of Breast Cancer: Genome High-Throughput Data Analysis

The high heterogeneity of breast cancer (BRCA) makes it more challenging to interpret the genetic variation mechanisms involved in BRCA pathogenesis and prognosis. Areas with high DNA methylation (such as CpG islands) were accompanied by copy number variation (CNV), and these genomic variations affected the level of DNA methylation. In this study, we characterized intertumor heterogeneity and analyzed the effects of CNV on DNA methylation and gene expression. In addition, we performed a Genetic Set Enrichment Analysis (GSEA) to identify key pathways for changes between patients with low and high expression of genes. Our analysis found two key genes, namely, HPDL and SOX17. The protein expressed by HPDL is 4-hydroxyphenylpyruvate dioxygenase-like protein, which has dioxygenase activity. SOX17 is a transcription factor that can inhibit Wnt signaling, promote the degradation of activated CTNNB1, and participate in cell proliferation. Our analysis found that the CNV of HPDL and SOX17 is not only related to the patient's prognosis, but also related to gene methylation and expression levels affecting the patient's survival time. Among them, the high-methylation, low-expression HPDL and SOX17 showed poor prognosis. And the addition of two copies of SOX17 is associated with a lower survival rate, while a decrease in the copy number of HPDL also suggests a poor prognosis. This study provided an effective bioinformatics basis for further exploration of molecular mechanisms related to BRCA and assessment of patient prognosis, but the development of biomarkers for diagnosis and treatment still requires further clinical data validation.

Circular RNAs regulate cancer-related signaling pathways and serve as potential diagnostic biomarkers for human cancers

Circular RNAs (circRNAs) are RNAs that have an important role in various pathological processes, including cancer. After the usage of high-throughput RNA sequencing, many circRNAs were found to be differentially expressed in various cancer cell lines and regulate cell signaling pathways by modulating particular gene expressions. Understanding their role in these pathways and what cancers they are found in can set the stage for identifying diagnostic and prognostic biomarkers and therapeutic targets of cancer. This paper will discuss which circRNAs are found in different cancers and what mechanisms they use to upregulate or downregulate certain cellular components.

The Roles of circRNAs in Liver Cancer Immunity

Circular RNAs (circRNAs) are stable covalently closed non-coding RNAs (ncRNAs). Many studies indicate that circRNAs are involved in the pathological and physiological processes of liver cancer. However, the functions of circRNAs in liver cancer immunity are less known. In this review, we summarized the functions of circRNAs in liver cancer, including proliferative, metastasis and apoptosis, liver cancer stemness, cell cycle, immune evasion, glycolysis, angiogenesis, drug resistance/sensitizer, and senescence. Immune escape is considered to be one of the hallmarks of cancer development, and circRNA participates in the immune escape of liver cancer cells by regulating natural killer (NK) cell function. CircRNAs may provide new ideas for immunotherapy in liver cancer.

Functions of Circular RNAs in Regulating Adipogenesis of Mesenchymal Stem Cells

The mesenchymal stem cells (MSCs) are known as highly plastic stem cells and can differentiate into specialized tissues such as adipose tissue, osseous tissue, muscle tissue, and nervous tissue. The differentiation of mesenchymal stem cells is very important in regenerative medicine. Their differentiation process is regulated by signaling pathways of epigenetic, transcriptional, and posttranscriptional levels. Circular RNA (circRNA), a class of noncoding RNAs generated from protein-coding genes, plays a pivotal regulatory role in many biological processes. Accumulated studies have demonstrated that several circRNAs participate in the cell differentiation process of mesenchymal stem cells in vitro and in vivo. In the current review, characteristics and functions of circRNAs in stem cell differentiation will be discussed. The mechanism and key role of circRNAs in regulating mesenchymal stem cell differentiation, especially adipogenesis, will be reviewed and discussed. Understanding the roles of these circRNAs will present us with a more comprehensive signal path network of modulating stem cell differentiation and help us discover potential biomarkers and therapeutic targets in clinic.

Circular RNA 0001073 Attenuates Malignant Biological Behaviours in Breast Cancer Cell and Is Delivered by Nanoparticles to Inhibit Mice Tumour Growth

Background

Circular RNAs (circRNAs) are a special class of noncoding RNAs that are involved in gene regulation and compete with mRNA for miRNA binding sites. The roles of circRNAs in cancer, especially breast cancer (BC), are poorly understood.

Materials and Methods

The expression levels of circRNA 0001073 (circ-1073) in BC cells (BCCs) and tissues and peritumoural tissues were detected by real-time quantitative reverse transcription-polymerase chain reaction. Kaplan–Meier analysis and receiver operating characteristic curves were used to evaluate relapse-free survival (RFS) and the diagnostic value of circ-1073 for BC, respectively. The biological functions of circ-1073 were determined by cell counting kit-8 assays, colony formation assays, flow cytometry, wound-healing assays, transwell assays, and xenograft model studies. RNA immunoprecipitation assays were conducted to identify the connection between circ-1073 and human antigen R (HuR).

Results

Low circ-1073 expression was discovered in BCCs and BC tissues compared with normal mammary epithelial cells and peritumoural tissues, respectively. Circ-1073 downregulation was significantly associated with an unfavourable prognosis, including a shorter RFS, in BC patients. Circ-1073 is a valuable diagnostic biomarker for BC. Circ-1073 overexpression significantly inhibited BCC proliferation and induced apoptosis by increasing Cleaved Caspase-3/9 levels. Moreover, circ-1073 upregulation significantly suppressed cell mobility and epithelial–mesenchymal transition. Notably, xenograft tumour growth was inhibited by the intratumoural injection of nanoparticles containing the circ-1073 plasmid or by circ-1073 overexpression, and this inhibition was accompanied by HuR upregulation.

Conclusion

Circ-1073 functions as a tumour suppressor in BC, suggesting its potential as a novel therapeutic target in BC.

Small Nucleolar RNA Host Gene 1 (SNHG1) and Chromosome 2 Open Reading Frame 48 (C2orf48) as Potential Prognostic Signatures for Liver Cancer by Constructing Regulatory Networks

Background

Liver cancer is a common malignant tumor with poor prognosis. The present study sought to identify potential signatures that can predict the prognosis of patients with liver cancer.

Material/Methods

The RNA sequencing (RNA-seq) and clinical information of liver cancer patients were obtained from the Cancer Genome Atlas (TCGA) database. Differentially expressed long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and messenger RNAs (mRNAs) were identified between liver cancer and adjacent normal tissues. After predicting lncRNA–miRNA and miRNA–mRNA pairs using online databases, the competing endogenous RNA (ceRNA) networks were constructed. Furthermore, the prognostic value of these differentially expressed genes was evaluated using univariate and multivariate Cox regression analyses.

Results

After constructing the ceRNA network, 2 lncRNAs small nucleolar RNA host gene 1 (SNHG1) and chromosome 2 open reading frame 48 (C2orf48) with the most nodes were identified. Correlation analysis revealed that SNHG1 was correlated with miR-195 and C2orf48 was correlated with miR-195 and miR-93. High expression of SNHG1, C2orf48, and miR-93 can contribute to poorer clinical outcomes compared to low expression. Furthermore, low miR-195 expression was correlated with shorter survival time than was high expression. SNHG1 and C2orf48 were closely associated with histology grade. Univariate and multivariate Cox regression analyses confirmed that SNHG1 and C2orf48 are risk factors for liver cancer.

Conclusions

Our findings revealed that SNHG1 and C2orf48 possess potential prognostic value and should be considered as possible biomarkers for predicting clinical outcomes for patients with liver cancer.

Advances on circRNAs Contribute to Carcinogenesis and Progression in Papillary Thyroid Carcinoma

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.

hsa_circRNA_100873 upregulation is associated with increased lymphatic metastasis of esophageal squamous cell carcinoma

Circular RNAs (circRNAs) are a type of endogenous non-coding RNA with multiple binding sites that specifically bind to microRNAs (miRNAs) and serve an important role in cellular regulatory networks. Patients exhibit varying levels of lymphatic metastasis in a clinical setting. The present study investigated the association between circRNAs and lymphatic metastasis in esophageal squamous cell carcinoma (ESCC). The tissue samples were divided into three groups, including early tumor stage associated with advanced nodal stage (T1 group), advanced tumor stage associated with early nodal stage (T2 group) and healthy esophageal epithelial tissues as the control group (C group). Gene chip analysis identified circRNAs, and those with possible regulatory functions were validated by reverse transcription-quantitative polymerase chain reaction analysis (RT-qPCR). circRNAs containing miRNA response element (MRE) sequences were obtained, and circRNA/miRNA prediction software was used to predict miRNAs that may interact with circRNA. A total of 12,275 circRNAs were detected, including 861 with statistically significant differences. A comparison between the T1 and C groups identified 152 upregulated circRNAs and 431 downregulated ones, while a comparison between the T2 and C groups identified 187 upregulated and 481 downregulated circRNAs. A T1/T2 group comparison revealed that four circRNAs were upregulated and seven were downregulated (fold change >1.5; P<0.05). The RT-qPCR data and gene chip analysis consistently identified hsa_circRNA_100873 as differentially expressed among the examined groups. A total of five potential MREs and complementary sequences were selected for hsa_circRNA_100873. The results of the present study indicated that multiple differentially expressed circRNAs are involved in the pathogenesis of ESCC, and that upregulation of hsa_circRNA_100873 may be associated with increased lymphatic metastases in ESCC.

Molecular mechanisms of circular RNAs, transforming growth factor-β, and long noncoding RNAs in hepatocellular carcinoma

At the heart of hepatocellular carcinoma (HCC) lies disruption of signaling pathways at the level of molecules, genes, and cells. Non‐coding RNAs (ncRNAs) have been implicated in the disease progression of HCC. For instance, dysregulated expression of circular RNAs (circRNAs) has been observed in patients with HCC. As such, these RNAs are potential therapeutic targets and diagnostic markers for HCC. Long non‐coding RNAs (lncRNAs), a type of ncRNA, have also been recognized to participate in the initiation and progression of HCC. Transforming growth factor‐beta (TGF‐β) is another element which is now recognized to play crucial roles in HCC. It has been implicated in many biological processes such as survival, immune surveillance, and cell proliferation. In HCC, TGF‐β promotes disease progression by two mechanisms: an intrinsic signaling pathway and the extrinsic pathway. Through these pathways, it modulates various microenvironment factors such as inflammatory mediators and fibroblasts. An interesting yet‐to‐be resolved concept is whether the HCC‐promoting role of TGF‐β pathways is limited to a subset of HCC patients or it is involved in the whole process of HCC development. This review summarizes recent advancements to highlight the roles of circRNAs, lncRNAs, and TGF‐β in HCC.

A circular RNA hsa_circ_0079929 inhibits tumor growth in hepatocellular carcinoma

Purpose

Most recently, circular RNAs (circRNAs) were considered playing regulatory roles in tumor initiation and development. The specific function of circRNAs in hepatocellular carcinoma (HCC) remains unknown. This study was designed to detect specific roles of a circRNA hsa_circ_0079299 in HCC.

Methods

The expression of hsa_circ_0079299 in HCC and tumor cell lines was detected using quantitative PCR (qPCR). Cell proliferation, migration, cell cycle and apoptosis after overexpression of the circRNA were measured using cell counting kit-8 (CCK8) assay, colony formation, 5-ethynyl-2′-deoxyuridine (EdU) assay, wound healing assay, transwell culture system and flow cytometry. Western blotting assay detected the protein expression of PI3K/AKT/mTOR signaling pathway and cyclin B1 (CCNB1). Overexpression of the circRNA in vivo was measured by nude mice tumorigenesis.

Results

The expression of hsa_circ_0079299 was lower in HCC tissues. Overexpression of hsa_circ_0079299 suppressed tumor growth in vitro and in vivo, retarded cell cycle progression while had no effect on cell migration and apoptosis. The inhibitory effect of hsa_circ_0079299 was partly mediated by PI3K/AKT/mTOR signaling pathway.

Conclusion

Our study shows that tumor suppressive role of hsa_circ_0079299 in HCC provides new recognition of circRNAs in cancers.

Circular RNAs: Characteristics, Function and Clinical Significance in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. HCC patients are commonly diagnosed at an advanced stage, for which highly effective therapies are limited. Moreover, the five-year survival rate of HCC patients remains poor due to high frequency of tumor metastasis and recurrence. These challenges give rise to the emergent need to discover promising biomarkers for HCC diagnosis and identify novel targets for HCC therapy. Circular RNAs (circRNAs), a class of long-overlook non-coding RNA, have been revealed as multi-functional RNAs in recent years. Growing evidence indicates that circRNA expression alterations have a broad impact in biological characteristics of HCC. Most of these circRNAs regulate HCC progression by acting as miRNA sponges, suggesting that circRNAs may function as promising diagnostic biomarkers and ideal therapeutic targets for HCC. In this review, we summarize the current progress in studying the functional role of circRNAs in HCC pathogenesis and present their potential values as diagnostic biomarkers and therapeutic targets. In-depth investigations on the function and mechanism of circRNAs in HCC will enrich our knowledge of HCC pathogenesis and contribute to the development of effective diagnostic biomarkers and therapeutic targets for HCC.