hsa_circ_0091570 acts as a ceRNA to suppress hepatocellular cancer progression by sponging hsa-miR-1307

Isthmin-1 and spexin as promising novel biomarker candidates for invasive ductal breast carcinoma

INTRODUCTION

Breast cancer is one of the most common malignant tumors and a leading cause of cancer-related death in women. Research is focusing on biomarkers linked to breast cancer, particularly two novel proteins: isthmin-1 (ISM-1) and spexin (SPX), which require further investigation.

MATERIAL AND METHODS

The study involved 20 healthy controls and 60 patients with invasive ductal carcinoma, categorized into three groups: Grade I (n=20), Grade II (n=20), and Grade III (n=20). Levels of ISM-1 and SPX in tissue were analyzed using immunohistochemistry alongside the clinicopathologic data of patients.

RESULTS

There were no statistically significant differences in age, menopausal status, ER, PR, and Cerb-B2 values across grades (p>0.05). Tumor diameters showed a significant increase in Grade I compared to Grade II (p<0.05), while no significant difference was noted between Grade II and Grade III, although diameters were larger in Grade III compared to Grade I (p<0.05). Notably, ISM-1 immunoreactivity decreased, and SPX immunoreactivity increased significantly across all grades compared to normal tissue (p<0.05), with no significant differences between tumor grades for these markers (p>0.05).

CONCLUSIONS

This study presents new findings on ISM-1 and SPX expression in invasive ductal breast carcinoma. The decrease in ISM-1 and increase in SPX suggest a need for further research into the relationship between adipokines and tumor development in breast cancer.

BCAR3 and BCAR3-related competing endogenous RNA expression in hepatocellular carcinoma and their prognostic value

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignant tumor that has a high incidence and mortality worldwide. Despite extensive studies, the detailed molecular mechanism of HCC development remains unclear. Studies have shown that the occurrence and development of HCC are closely related to abnormal gene expression. BCAR3 has been shown to be overexpressed in a variety of malignant tumors. However, the role of BCAR3 in HCC remains unclear.

AIM

To investigate the expression of BCAR3 and BCAR3-related competing endogenous RNAs (ceRNAs) in HCC and their clinical significance, in order to provide new ideas for the diagnosis and treatment of HCC.

METHODS

The data of HCC were obtained from the Cancer Genome Atlas database and The Genotype Tissue Expression, including transcriptome data and clinical information. Multiple common databases, including UALCAN, Timer 2.0, cBioPortal, LinkedOmics, starBase, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes, were used to analyse the expression of BCAR3, prognostic value, genetic alteration, co-expressed genes, differentially expressed genes, BCAR3 gene-related ceRNAs and functional enrichment analysis in HCC patients. Kaplan-Meier analysis, univariate and multivariate Cox regression analysis were used to analyze survival prognosis and the Spearman test was used to measure correlations between BCAR3 and immune functions. And R language package was used to analyze the correlation between BCAR3 and immune invasion of HCC.

RESULTS

Our study indicated that BCAR3 was differentially expressed in various tumor tissues. The over-expression of BCAR3 gene was an unfavorable prognostic indicator for HCC patients, and associated with unfavorable cytogenetic risk and gene mutations. Moreover, most immune cells were positively correlated with BCAR3 (P < 0.05). According to the results of functional enrichment analysis, BCAR3 was involved in the positive regulation of epidermal growth factor receptor signaling pathway and ERBB signaling pathway, and was related to DNA replication and GTPase regulator activity. Finally, our study found that based on RAB30-DT and miR-19b-3p pathways, targeting BCAR3 might promote the occurrence and development of HCC.

CONCLUSION

Collectively, this study indicated that the BCAR3 gene was involved in the occurrence and development of HCC, and it might be a new biomarker and therapeutic target for HCC, but the specific mechanism remains to be further verified.

CircGNAO1 strengthens its host gene GNAO1 expression for suppression of hepatocarcinogenesis

Background

Hepatocellular carcinoma (HCC) is one of the most prevalent primary liver carcinoma. Guanine nucleotide-binding protein, α-activating activity polypeptide O (GNAO1) was reported to be under-expressed in HCC tissues. This study aimed to investigate the GNAO1-derived circular RNA (circRNA) and its molecular mechanisms in HCC.

Methods

Real-time quantitative polymerase chain reaction (RT-qPCR) and Western blot were applied to examine RNA and protein levels. Functional experiments were performed to study HCC cell proliferation, cell cycle and cellular senescence. The interactions among circGNAO1, GNAO1 and DNA methyltransferase 1 (DNMT1) were examined by mechanism assays. The methylation level was analyzed by bisulfite sequencing PCR (BSP).

Results

CircGNAO1 is down-regulated and positively associated with GNAO1 in HCC tissues. Overexpression of circGNAO1 inhibits cell proliferation, induces cell cycle arrest and facilitates cell senescence in HCC cells. CircGNAO1 facilitates the progression of HCC via modulating GNAO1. Mechanistically, circGNAO1 enhances the transcription of GNAO1 by sequestering DNMT1, thereby up-regulating GNAO1 expression in HCC cells.

Conclusions

CircGNAO1 up-regulates its host gene GNAO1 expression for suppression of hepatocarcinogenesis.

Construction of a ceRNA network and screening of potential biomarkers and molecular targets in male smokers with chronic obstructive pulmonary disease

Background

Circular RNAs (circRNAs) play an important role in the occurrence and development of diseases. However, the role of circRNAs in male smokers with chronic obstructive pulmonary disease (COPD) remains unclear.

Methods

Stable COPD patients and healthy controls were recruited. Peripheral blood mononuclear cells (PBMCs) were extracted. After high-throughput RNA sequencing (RNA-Seq) of PBMCs, a bioinformatics method was used to analyse differentially expressed (DE) circRNAs (DEcircRNAs) and mRNAs (DEmRNAs).

Results

Total of 114 DEcircRNAs and 58 DEmRNAs were identified. Functional enrichment analysis showed that processes related to COPD include the regulation of interleukin (IL)-18, IL-5 and the NLRP3 inflammasome; differentiation of T helper type 1 (Th1), Th2, and Th17 cells, and the AMPK, Wnt, JAK-STAT, and PI3K-Akt signalling pathways. In the protein-protein interaction (PPI) network, the core genes were MYO16, MYL4, SCN4A, NRCAM, HMCN1, MYOM2, and IQSEC3. Small-molecule prediction results revealed potential drugs for the COPD treatment. Additionally, the circRNA-miRNA-mRNA competitive endogenous RNA (ceRNA) regulatory network was constructed.

Conclusion

This study identified a set of dysregulated circRNAs and mRNAs and revealed potentially important genes, pathways, new small-molecule drugs and ceRNA regulatory networks in male smokers with COPD. These circRNAs might be prospective biomarkers or potential molecular targets of the ceRNA mechanism for COPD.

Molecular Mechanisms in Tumorigenesis of Hepatocellular Carcinoma and in Target Treatments-An Overview

Hepatocellular carcinoma is the most common primary malignancy of the liver, with hepatocellular differentiation. It is ranked sixth among the most common cancers worldwide and is the third leading cause of cancer-related deaths. The most important etiological factors discussed here are viral infection (HBV, HCV), exposure to aflatoxin B1, metabolic syndrome, and obesity (as an independent factor). Directly or indirectly, they induce chromosomal aberrations, mutations, and epigenetic changes in specific genes involved in intracellular signaling pathways, responsible for synthesis of growth factors, cell proliferation, differentiation, survival, the metastasis process (including the epithelial-mesenchymal transition and the expression of adhesion molecules), and angiogenesis. All these disrupted molecular mechanisms contribute to hepatocarcinogenesis. Furthermore, equally important is the interaction between tumor cells and the components of the tumor microenvironment: inflammatory cells and macrophages-predominantly with a pro-tumoral role-hepatic stellate cells, tumor-associated fibroblasts, cancer stem cells, extracellular vesicles, and the extracellular matrix. In this paper, we reviewed the molecular biology of hepatocellular carcinoma and the intricate mechanisms involved in hepatocarcinogenesis, and we highlighted how certain signaling pathways can be pharmacologically influenced at various levels with specific molecules. Additionally, we mentioned several examples of recent clinical trials and briefly described the current treatment protocol according to the NCCN guidelines.

Targeting non-coding RNAs and N6-methyladenosine modification in hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common form of primary liver cancers, accounts for a significant portion of cancer-related death globally. However, the molecular mechanisms driving the onset and progression of HCC are still not fully understood. Emerging evidence has indicated that non-protein-coding regions of genomes could give rise to transcripts, termed non-coding RNA (ncRNA), forming novel functional driving force for aberrant cellular activity. Over the past decades, overwhelming evidence has denoted involvement of a complex array of molecular function of ncRNAs at different stages of HCC tumorigenesis and progression. In this context, several pre-clinical studies have highlighted the potentials of ncRNAs as novel therapeutic modalities in the management of human HCC. Moreover, N6-methyladenosine (m6A) modification, the most prevalent form of internal mRNA modifications in mammalian cells, is essential for the governance of biological processes within cells. Dysregulation of m6A in ncRNAs has been implicated in human carcinogenesis, including HCC. In this review, we will discuss dysregulation of several hallmark ncRNAs (miRNAs, lncRNAs, and circRNAs) in HCC and address the latest advances for their involvement in the onset and progression of HCC. We also focus on dysregulation of m6A modification and various m6A regulators in the etiology of HCC. In the end, we discussed the contemporary preclinical and clinical application of ncRNA-based and m6A-targeted therapies in HCC.

CircRNA circRREB1 promotes tumorigenesis and progression of breast cancer by activating Erk1/2 signaling through interacting with GNB4

Current investigations have illuminated the essential roles played by circular RNAs (circRNAs) in driving breast cancer (BC) tumorigenesis. However, the functional implications and molecular underpinnings of most circRNAs in BC are not well characterized. Here, Circular RNA (circRNA) expression profiles were analyzed in four surgically resected BC cases along with adjacent non-cancerous tissues applying RNA microarray analysis. The levels and prognostic implications of circRREB1 in BC were subjected to quantitative real-time PCR (qRT-PCR) and in situ hybridization (ISH). Experimental manipulation of circRREB1 levels in both in vivo and in vitro settings further delineated its role in BC cell growth, invasion, and metastasis. The mechanical verification of circRREB1's interaction with GNB4 was established through RNA pull-down, mass spectrometry, Western blot analysis, RNA immunoprecipitation assays (RIP), fluorescence ISH (FISH), and rescue experiments. We found that circRREB1 exhibited significant upregulation in BC tissues and cells, implicating its association with an unfavorable prognosis in BC patients. CircRREB1 knockdown elicited anti-proliferative, anti-migratory, anti-invasive, and pro-apoptotic effects in BC cells, whereas its upregulation exerted opposing influences. Follow-up mechanistic examinations suggested that circRREB1 might interact with GNB4 directly, inducing the activation of Erk1/2 signaling and driving BC progression. Our findings collectively indicate that the interplay of circRREB1 with GNB4 promotes Erk1/2 signaling, thereby fostering BC progression, and positioning circRREB1 as a candidate therapeutic target for intervention in BC.

Involvement of CircRNAs in regulating The "New Generation of Cancer Hallmarks": A Special Depiction on Hepatocellular Carcinoma

The concept of 'Hallmarks of Cancer' is an approach of reducing the enormous complexity of cancer to a set of guiding principles. As the underlying mechanism of cancer are portrayed, we find that we gain insight and additional aspects of the disease arise. The understanding of the tumor microenvironment (TME) brought a new dimension and led to the discovery of novel hallmarks such as senescent cells, non-mutational epigenetic reprogramming, polymorphic microbiomes and unlocked phenotypic plasticity. Circular RNAs (circRNAs) are single-stranded, covalently closed RNA molecules that are ubiquitous across all species. Recent studies on the circRNAs have highlighted their crucial function in regulating the formation of human malignancies through a range of biological processes. The primary goal of this review is to clarify the role of circRNAs in the most common form of liver cancer, hepatocellular carcinoma (HCC). This review also addressed the topic of how circRNAs affect HCC hallmarks, including the new generation hallmarks. Finally, the enormous applications that these rapidly expanding ncRNA molecules serve in the functional and molecular development of effective HCC diagnostic biomarkers and therapeutic targets.

Aspongopus chinensis Dallas induces pro-apoptotic and cell cycle arresting effects in hepatocellular carcinoma cells by modulating miRNA and mRNA expression

Aspongopus chinensis Dallas is a traditional Chinese medicinal insect with several anticancer properties can inhibit cancer cell growth, by inhibiting cell division, autophagy and cell cycle. However, the precise therapeutics effects and mechanisms of this insect on liver cancer are still unknown. This study examined the inhibitory influence of A. chinensis on the proliferation of hepatocellular carcinoma (HCC) cells and explore the underlying mechanism using high-throughput sequencing. The results showed that A. chinensis substantially reduced the viability of Hep G2 cells. A total of 33 miRNAs were found to be upregulated, while 43 miRNAs were downregulated. Additionally, 754 mRNAs were upregulated and 863 mRNAs were downregulated. Significant enrichment of differentially expressed genes was observed in signaling pathways related to tumor cell growth, cell cycle regulation, and apoptosis. Differentially expressed miRNAs exhibited a targeting relationship with various target genes, including ARC, HSPA6, C11orf86, and others. Hence, cell cycle and apoptosis were identified by flow cytometry. These findings indicate that A. chinensis impeded cell cycle advancement, halted the cell cycle in the G0/G1 and S stages, and stimulated apoptosis. Finally, mouse experiments confirmed that A. chinensis significantly inhibits tumor growth in vivo. Therefore, our findings indicate that A. chinensis has a notable suppressive impact on the proliferation of HCC cells. The potential mechanism of action could involve the regulation of mRNA expression via miRNA, ultimately leading to cell cycle arrest and apoptosis. The results offer a scientific foundation for the advancement and application of A. chinensis in the management of HCC.

N6-methyladenosine-modified circ_104797 sustains cisplatin resistance in bladder cancer through acting as RNA sponges

BACKGROUND

Bladder cancer (BCa) ranks among the predominant malignancies affecting the urinary system. Cisplatin (CDDP) remains a cornerstone therapeutic agent for BCa management. Recent insights suggest pivotal roles of circular RNA (circRNA) and N6-methyladenosine (m6A) in modulating CDDP resistance in BCa, emphasizing the importance of elucidating these pathways to optimize cisplatin-based treatments.

METHODS

Comprehensive bioinformatics assessments were undertaken to discern circ_104797 expression patterns, its specific interaction domains, and m6A motifs. These findings were subsequently corroborated through experimental validations. To ascertain the functional implications of circ_104797 in BCa metastasis, in vivo assays employing CRISPR/dCas13b-ALKBH5 were conducted. Techniques, such as RNA immunoprecipitation, biotin pull-down, RNA pull-down, luciferase reporter assays, and western blotting, were employed to delineate the underlying molecular intricacies.

RESULTS

Our investigations revealed an elevated expression of circ_104797 in CDDP-resistant BCa cells, underscoring its pivotal role in sustaining cisplatin resistance. Remarkably, demethylation of circ_104797 markedly augmented the potency of cisplatin-mediated apoptosis. The amplification of circ_104797 in CDDP-resistant cells was attributed to enhanced RNA stability, stemming from an augmented m6A level at a distinct adenosine within circ_104797. Delving deeper, we discerned that circ_104797 functioned as a microRNA reservoir, specifically sequestering miR-103a and miR-660-3p, thereby potentiating cisplatin resistance.

CONCLUSIONS

Our findings unveil a previously uncharted mechanism underpinning cisplatin resistance and advocate the potential therapeutic targeting of circ_104797 in cisplatin-administered patients with BCa, offering a promising avenue for advanced BCa management.

Recent research progress of circular RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is an extremely heterogeneous malignant tumor with a high morbidity and mortality. Circular RNAs (circRNAs) are noncoding RNAs with high stability, organ/tissue/cell-specific expression and are conserved across species. Accumulating evidence suggested that circRNAs play crucial roles as microRNA sponges, protein sponges, scaffolds, recruiters and could even polypeptide encoders. Many studies have since revealed that circRNAs were aberrantly expressed in HCC and acted as crucial modulators of HCC carcinogenesis and progression. Furthermore, circRNAs have also been identified as potential diagnostic and prognostic biomarkers for HCC. In this review, we thoroughly outline and evaluate the function of circRNAs in HCC development, with an emphasis on the specific molecular pathways by which they participated in the formation and progression of HCC, and we address their potential for serving as clinical biomarkers in HCC.

Isthmin: A multifunctional secretion protein

Isthmin is a polypeptide secreted by adipocytes that was first detected in Xenopus gastrula embryos. Recent studies have focused on the biological functions of isthmin in growth and development, angiogenesis, and metabolism. Distinct spatiotemporal expression of isthmin-1 (ISM-1) was observed during growth and development. ISM-1 plays an important role in the occurrence and development of cancer by regulating cell proliferation, migration, angiogenesis, and immune microenvironments. Moreover, ISM-1, as a newly identified insulin-like adipokine, increases adipocyte glucose uptake and inhibits hepatic lipid synthesis. However, the biological function of ISM-1 remains largely unknown. In this review, we highlight the structure and physiological functions of isthmin and explore its application potential, contributing to a better understanding of its function and providing prevention and treatment strategies for various diseases.

Hsa_circ_0084912 Drives the Progression of Cervical Cancer Via Regulating miR-429/SOX2 Pathway

We focus on hsa_circ_0084912's role in Cervical cancer (CC) and its molecular pathways. In order to determine the expression of Hsa_circ_0084912, miR-429, and SOX2 in CC tissues and cells, Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) were utilized. Cell counting kit 8 (CCK-8), colony formation and Transwell assays were respectively to analyze CC cell proliferation viability, clone formation ability and migration. RNA immunoprecipitation (RIP) assay and dual-luciferase assay were used to assure the targeting correlation among hsa_circ_0084912/SOX2 and miR-429. By using a xenograft tumor model, the hsa_circ_0084912 impact on CC cell proliferation in vivo was confirmed. Hsa_circ_0084912 and SOX2 expressions were aggrandized, however, miR-429 expression was descended in CC tissues and cells. Silencing hsa_circ_0084912 inhibited cell proliferation, colony formation and migration in vitro of CC, meanwhile reducing growth of tumor in vivo. MiR-429 might be sponged by Hsa_circ_0084912 to control SOX2 expression. Hsa_circ_0084912 knockdown impact on the malignant phenotypes of CC cells was restored by miR-429 inhibitor. Moreover, SOX2 silencing eliminated the promotive effects of miR-429 inhibitors on CC cell malignancies. By raising SOX2 expression by targeting miR-429, hsa_circ_0084912 accelerated the development of CC, offering fresh proof that it is a viable target for CC treatment.

Circ_0102231 inactivates the PI3K/AKT signaling pathway by regulating the miR-635/NOVA2 pathway to promote the progression of non-small cell lung cancer

BACKGROUND

Circular RNAs (circRNAs) are involved in the malignant development of tumors. However, the mechanism of circ_0102231 in non-small cell lung cancer (NSCLC) has rarely been discussed and reported.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of circ_0102231, miR-635 and NOVA alternative splicing regulator 2 (NOVA2) in NSCLC tissues and cells. Western blot was applied to detect the protein expression. Cell proliferation was monitored by cell counting kit-8 (CCK8) and 5-ethynyl-2'-deoxyuridine (EdU) experiments. The angiogenesis ability of cells was tested by angiogenesis assay. Flow cytometry was used to analyze cell apoptosis. The relationship between circ_0102231 and NOVA2 or miR-635 was analyzed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. An in vivo transplanted tumor model was established to confirm the effect of circ_0102231 on tumor formation.

RESULTS

Circ_0102231 was abnormally upregulated in NSCLC tissues and correlated with clinical stage. Silencing of circ_0102231 inhibited cell proliferation and angiogenesis but significantly promoted the apoptosis of NSCLC cells. There were target binding sites between circ_0102231 and miR-635, miR-635 and NOVA2. Importantly, circ_0102231 acted as a sponge for miR-635, increased the expression of NOVA2, and activated the PI3K/AKT signaling pathway. Finally, silencing of circ_0102231 also had obvious antitumor effects in vivo.

CONCLUSION

Circ_0102231 increased the expression of NOVA2 by interacting with miR-635 to promote the malignant progression of NSCLC.

Advances in research of biological functions of Isthmin-1

Isthmin-1 (ISM1) was initially thought to be a brain secretory factor, but with the development of technical means of research and the refinement of animal models, numerous studies have shown that this molecule is expressed in multiple tissues, suggesting that it may have multiple biological functions. As a factor that regulates growth and development, ISM1 is expressed in different animals with spatial and temporal variability and can coordinate the normal development of multiple organs. Recent studies have found that under the dependence of a non-insulin pathway, ISM1 can lower blood glucose, inhibit insulin-regulated lipid synthesis, promote protein synthesis, and affect the body's glucolipid and protein metabolism. In addition, ISM1 plays an important role in cancer development by promoting apoptosis and anti-angiogenesis, and by regulating multiple inflammatory pathways to influence the body's immune response. The purpose of this paper is to summarize relevant research results from recent years and to describe the key features of the biological functions of ISM1. We aimed to provide a theoretical basis for the study of ISM1 related diseases, and potential therapeutic strategies. The main biological functions of ISM1. Current studies on the biological functions of ISM1 focus on growth and development, metabolism, and anticancer treatment. During embryonic development, ISM1 is dynamically expressed in the zebrafish, African clawed frog, chick, mouse, and human, is associated with craniofacial malformations, abnormal heart localization, and hematopoietic dysfunction. ISM1 plays an important role in regulating glucose metabolism, lipid metabolism, and protein metabolism in the body. ISM1 affects cancer development by regulating cellular autophagy, angiogenesis, and the immune microenvironment.

Circular RNA circ_0000119 promotes cervical cancer cell growth and migration via miR-433-3p/PAK2 axis

The purpose of this study was to investigate the role of circ_0000119 on CC progression and its molecular mechanism. The expression levels of circ_0000119, miR-433-3p, and p21-activated kinase 2 (PAK2) in CC tissues and cell lines were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed using 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di-phenytetrazoliumromide (MTT) assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay and colony formation assay. Cell cycle and apoptosis were assessed by flow cytometry. Cell migration and invasive ability were examined by Transwell assays. Downstream binding targets of circ_0000119 were predicted by online bioinformatics tools and confirmed by dual luciferase reporter gene assay, RNA immunoprecipitation (RIP) assay, and RNA pull-down assay. The role of circ_0000119/miR-433-3p/PAK2 axis in regulating the CC process was explored by rescue experiments. A xenograft model was constructed to further determine the effect of circ_0000119 on CC tumor growth in vivo. Immunohistochemistry (IHC) assay was conducted for Ki67 expression. Circ_0000119 was aberrantly upregulated in CC tissues and cell lines. Knockdown of circ_0000119 inhibited CC cell proliferation, cell cycle progress, migration, invasion, and promoted apoptosis of CC cells. MiR-433-3p was a binding target of circ_0000119, and PAK2 was a downstream gene of miR-433-3p. MiR-433-3p inhibition reversed the inhibitory effect of silencing circ_0000119 on CC progression. In addition, PAK2 overexpression reversed the effect of miR-433-3p on CC progression. PAK2 expression was regulated by circ_0000119 and miR-433-3p. Moreover, circ_0000119 knockdown reduced tumor growth of CC in vivo. Circ_0000119 was upregulated in CC, and circ_0000119 knockdown suppressed CC malignant development through the miR-433-3p/PAK2 axis.

CircRNA hsa_circ_0000043 acts as a miR-4492 sponge to promote lung cancer progression via BDNF and STAT3 expression regulation in anti-benzo[a]pyrene-trans-7,8-dihydrodiol-9,10-epoxide-transformed 16HBE cells

Increasing evidence shows that circular RNA (circRNA) plays an important role in the progression of lung cancer. In this study, we found that has_circ_0000043 was highly expressed in 16HBE-T human bronchial epithelial cells that were malignantly transformed by benzo[a]pyrene-trans-7,8-diol-9,10-epoxide via circRNA microarray. We verified that hsa_circ_0000043 was also significantly overexpressed in lung cancer cell lines and tissues. Moreover, hsa_circ_0000043 overexpression was positively correlated with poor clinicopathological parameters, such as tumor-node metastasis stage, distant metastasis, lymph-node metastasis, and overall survival. In vitro assays revealed that hsa_circ_0000043 inhibition suppressed 16HBE-T cell proliferation, migration, and invasion. Furthermore, hsa_circ_0000043 inhibition suppressed tumor growth in a mouse xenograft model. We discovered that hsa_circ_0000043 binds with miR-4492, acting as a miR-4492 sponge. Decreased miR-4492 expression was also associated with poor clinicopathological parameters. Thus, hsa_circ_0000043 was shown to contribute to the proliferation, malignant transformation ability, migration, and invasion of 16HBE-T cells via miR-4492 sponging and BDNF and STAT3 involvement.

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.

Serum Isthmin-1 Was Increased in Type 2 Diabetic Patients but Not in Diabetic Sensorimotor Peripheral Neuropathy

Purpose

This study aimed to investigate the relationship between serum isthmin-1 (ISM1) and type 2 diabetes mellitus (T2DM), and the alteration of serum ISM1 level in both diabetic sensorimotor peripheral neuropathy (DSPN) and diabetic adults with obesity.

Patients and Methods

We recruited 180 participants (120 T2DM and 60 controls) in the cross-sectional study. First, we compared the serum ISM1 concentration in diabetic patients and non-diabetic controls. Secondly, according to DSPN, patients were divided into DSPN and non-DSPN groups. Last, patients were categorized as lean T2DM (15 males, 15 females), overweight T2DM (35 males, 19 females), and obese T2DM groups (23 males, 13 females) according to gender and body mass index (BMI). All participants were collected with clinical characteristics and biochemical profiles. Serum ISM1 was detected in all subjects by ELISA.

Results

Higher serum ISM1 [7.78 ng/mL (IQR: 6.33-9.06) vs 5.22 (3.86-6.04), P <0.001] was observed in diabetic patients compared to non-diabetic controls. Binary logistic regression analysis showed that serum ISM1 was a risk factor for type 2 diabetes after adjustment (OR=4.218, 95% CI: 1.843-9.653, P=0.001). Compared to the non-DSPN group, serum ISM1 level was not changed significantly in patients who suffered from DSPN. Diabetic females with obesity had lower level of serum ISM1 (7.10±1.29 ng/mL) when compared to the lean T2DM (8.42±1.36 ng/mL, P <0.05) and the overweight T2DM (8.33±1.27 ng/mL, P <0.05). However, serum ISM1 was not changed significantly in male groups or all patients together.

Conclusion

Serum ISM1 was a risk factor for type 2 diabetes, and it was associated with diabetic adults with obesity while there was sexual dimorphism. However, serum ISM1 levels were not correlated with DSPN.

Circular RNA hsa_circ_0000519 contributes to angiogenesis and tumor progression in hepatocellular carcinoma through the miR-1296/E2F7 axis

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy. Uncontrolled angiogenesis plays a critical role in hepatocellular tumor growth and metastasis. In this study, we aimed to investigate the effects of circular RNA hsa_circ_0000519 and the potential involvement of microRNA (miR)-1296 and E2F transcription factor 7 (E2F7) in HCC development. Hsa_circ_0000519 was highly expressed in HCC cells and hepatocellular tumor tissues, and correlated with poor prognosis of HCC patients. Knockdown of hsa_circ_0000519 significantly reduced HCC cell viability, suppressed cell proliferation, and induced cell cycle arrest in G0/G1. Downregulation of hsa_circ_0000519 also inhibited formation of capillary-like endothelial structures in vitro and impeded microvessel formation in mice bearing HCC tumors. The migration and invasive capacities of HCC cells were markedly reduced by hsa_circ_0000519 knockdown. Hsa_circ_0000519 possessed a binding site for microRNA (miR)-1296. Upregulation of hsa_circ_0000519 significantly decreased the miR-1296 expression in both HCC cells and mouse xenografts. Furthermore, E2F7 was a target of miR-1296. Hsa_circ_0000519 positively regulated E2F7 via acting as a miR-1296 sponge. Upregulation of E2F7 abolished the inhibitory effects of hsa_circ_0000519 knockdown on HCC cell proliferation and angiogenesis. In conclusion, hsa_circ_0000519 promoted tumor progression and angiogenesis in HCC through the miR-1296/E2F7 axis. These data suggest the potential clinical application of hsa_circ_0000519 in HCC treatment.

Isthmin-A Multifaceted Protein Family

Isthmin (ISM) is a secreted protein family with two members, namely ISM1 and ISM2, both containing a TSR1 domain followed by an AMOP domain. Its broad expression pattern suggests diverse functions in developmental and physiological processes. Over the past few years, multiple studies have focused on the functional analysis of the ISM protein family in several events, including angiogenesis, metabolism, organ homeostasis, immunity, craniofacial development, and cancer. Even though ISM was identified two decades ago, we are still short of understanding the roles of the ISM protein family in embryonic development and other pathological processes. To address the role of ISM, functional studies have begun but unresolved issues remain. To elucidate the regulatory mechanism of ISM, it is crucial to determine its interactions with other ligands and receptors that lead to the activation of downstream signalling pathways. This review provides a perspective on the gene organization and evolution of the ISM family, their links with developmental and physiological functions, and key questions for the future.

Multifunctional Carbon-Dot-Photosensitizer Nanoassemblies for Inhibiting Amyloid Aggregates, Suppressing Microbial Infection, and Overcoming the Blood-Brain Barrier

Amyloid aggregation, microbial infection, and the blood-brain barrier (BBB) are considered critical obstructions for the treatment of Alzheimer's disease (AD). At present, existing treatment strategies are rarely able to overcome these critical factors. Herein, we propose an innovative treatment strategy and design multifunctional nanoassemblies (yCDs-Ce6) from coassembling photosensitizers (chlorine e6) and yellow fluorescent carbon dots, which endow yCDs-Ce6 with the functions for photodynamic and photothermal therapy (PDT and PTT). Compared with reported inhibitors, yCDs-Ce6 can suppress amyloid aggregation for 7 days, disaggregate aggregates, reduce amyloid aggregation-induced cytotoxicity, and prevent microbial growth by PDT and PTT. Moreover, yCDs-Ce6 can specifically target amyloid aggregates and visually label amyloid aggregates. yCDs-Ce6 can also cross the BBB upon near-infrared light irradiation and clear amyloid deposition in APP/PS1 mice by PDT and PTT. Meanwhile, yCDs-Ce6 did not cause significant negative effects on normal cells or tissues. Based on the methods of PPT and PTT treatment, the research deeply explores the effect of the novel nanoassemblies on two hypotheses of AD, opening a novel therapeutic paradigm for research amyloid-related diseases.

Hsa_circ_0040809 and hsa_circ_0000467 promote colorectal cancer cells progression and construction of a circRNA-miRNA-mRNA network

Objective: Circular RNAs (circRNAs) have been demonstrated to be closely involved in colorectal cancer (CRC) pathogenesis and metastasis. More potential biomarkers are needed to be searched for colorectal cancer (CRC) diagnosis and treatment. The objective of this study is to seek differentially expressed circRNAs (DEcircRNAs), test their roles in CRC and construct a potential competing endogenous RNA (ceRNA) network.

Methods: CircRNA microarrays were obtained from Gene Expression Omnibus, and differential expression was analyzed by R software. The relative expressions of DEcircRNAs were confirmed in CRC tissues and cell lines by qRT-PCR. MTs and Transwell experiments were performed for detecting the roles of circRNAs on CRC cell proliferation and migration, respectively. Targeted miRNAs of circRNAs and targeted mRNAs of miRNAs were predicted and screened by bioinformatics methods. A ceRNA network of DEcircRNAs was constructed by Cytoscape. To further verify the potential ceRNA network, the expressions of miRNAs and mRNAs in knockdown of DEcircRNAs CRC cells were detected by qRT-PCR.

Results: Two DEcircRNAs (hsa_circ_0040809 and hsa_circ_0000467) were identified and validated in CRC tissues and cell lines. The results of MTs and Transwell experiments showed that hsa_circ_0040809 and hsa_circ_0000467 promoted CRC proliferation and migration. Bioinformatics analysis screened 3 miRNAs (miR-326, miR-330-5p, and miR-330-3p) and 2 mRNAs (FADS1 and RUNX1), and a ceRNA network was constructed. In knockdown of hsa_circ_0040809 HCT-116 cells, the expression of miR-330-3p was significantly upregulated, while RUNX1 was significantly downregulated. In knockdown of hsa_circ_0000467 HCT-116 cells, the expressions of miR-326 and miR-330-3p were upregulated, while FADS1was downregulated.

Conclusion: We found that hsa_circ_0040809 and hsa_circ_0000467 were upregulated in CRC tissues and cell lines, and promoted CRC cell progression. A circRNA-miRNA-mRNA network based on hsa_circ_0040809 and hsa_circ_0000467 was constructed.

MALAT1-miRNAs network regulate thymidylate synthase and affect 5FU-based chemotherapy

Background

The active metabolite of 5-Fluorouracil (5FU), used in the treatment of several types of cancer, acts by inhibiting the thymidylate synthase encoded by the TYMS gene, which catalyzes the rate-limiting step in DNA replication. The major failure of 5FU-based cancer therapy is the development of drug resistance. High levels of TYMS-encoded protein in cancerous tissues are predictive of poor response to 5FU treatment. Expression of TYMS is regulated by various mechanisms, including involving non-coding RNAs, both miRNAs and long non-coding RNAs (lncRNAs).

Aim

To delineate the miRNAs and lncRNAs network regulating the level of TYMS-encoded protein.

Main body

Several miRNAs targeting TYMS mRNA have been identified in colon cancers, the levels of which can be regulated to varying degrees by lncRNAs. Due to their regulation by the MALAT1 lncRNA, these miRNAs can be divided into three groups: (1) miR-197-3p, miR-203a-3p, miR-375-3p which are downregulated by MALAT1 as confirmed experimentally and the levels of these miRNAs are actually reduced in colon and gastric cancers; (2) miR-140-3p, miR-330-3p that could potentially interact with MALAT1, but not yet supported by experimental results; (3) miR-192-5p, miR-215-5p whose seed sequences do not recognize complementary response elements within MALAT1. Considering the putative MALAT1-miRNAs interaction network, attention is drawn to the potential positive feedback loop causing increased expression of MALAT1 in colon cancer and hepatocellular carcinoma, where YAP1 acts as a transcriptional co-factor which, by binding to the TCF4 transcription factor/ β-catenin complex, may increase the activation of the MALAT1 gene whereas the MALAT1 lncRNA can inhibit miR-375-3p which in turn targets YAP1 mRNA.

Conclusion

The network of non-coding RNAs may reduce the sensitivity of cancer cells to 5FU treatment by upregulating the level of thymidylate synthase.

A brief overview about the adipokine: Isthmin-1

Isthmin-1 is a secreted protein with multiple capability; however, it truly attracts our attention since the definition as an adipokine in 2021, which exerts indispensable roles in various pathophysiological processes through the endocrine or autocrine manners. In this review, we summarize recent knowledge of isthmin-1, including its distribution, structure, receptor and potential function.

Engineered exosome-mediated delivery of circDIDO1 inhibits gastric cancer progression via regulation of MiR-1307-3p/SOCS2 Axis

Background

Our previous study has identified a novel circRNA (circDIDO1) that is down-regulated in gastric cancer (GC) and significantly inhibits GC progression. The purpose of this study is to identify the molecular mechanism for circDIDO1 and to evaluate the therapeutic effect of circDIDO1 in GC.

Methods

By combining bioinformatic analysis with RNA sequencing data, we predicted the potential target of circDIDO1 and further validated the regulatory mechanisms for its tumor suppressor function in GC. RIP assay, luciferase reporter assay and in vitro cell function assays were performed to analyze circDIDO1-regulated downstream target genes. For the therapeutic study, circDIDO1-loaded, RGD-modified exosomes (RGD-Exo-circDIDO1) were constructed and its anti-tumor efficacy and biological safety were evaluated in vitro and in vivo.

Results

CircDIDO1 inhibited GC progression by regulating the expression of the signal transducer inhibitor SOSC2 through sponging miR-1307-3p. Overexpression of circDIDO1 or SOSC2 antagonized the oncogenic role of miR-1307-3p. RGD-Exo-circDIDO1 could efficiently deliver circDIDO1 to increase SOCS2 expression in GC cells. Compared with PBS and RGD-Exo-vector treatment, RGD-Exo-circDIDO1 treatment significantly inhibited the proliferation, migration and invasion of GC cells while promoted cell apoptosis. The therapeutic efficacy of RGD-Exo-circDIDO1 was further confirmed in a mouse xenograft tumor model. In addition, major tissues including the heart, liver, spleen, lungs and kidneys showed no obvious histopathological abnormalities or lesions in the RGD-Exo-circDIDO1 treated group.

Conclusion

Our findings revealed that circDIDO1 suppressed the progression of GC via modulating the miR-1307-3p/SOSC2 axis. Systemic administration of RGD modified, circDIDO1 loaded exosomes repressed the tumorigenicity and aggressiveness of GC both in vitro and in vivo, suggesting that RGD-Exo-circDIDO1 could be used as a feasible nanomedicine for GC therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03527-z.

Noncoding RNA-mediated macrophage and cancer cell crosstalk in hepatocellular carcinoma

The tumor microenvironment (TME) is a well-recognized system that plays an essential role in tumor initiation, development, and progression. Intense intercellular communication between tumor cells and other cells (especially macrophages) occurs in the TME and is mediated by cell-to-cell contact and/or soluble messengers. Emerging evidence indicates that noncoding RNAs (ncRNAs) are critical regulators of the relationship between cells within the TME. In this review, we provide an update on the regulation of ncRNAs (primarily micro RNAs [miRNAs], long ncRNAs [lncRNAs], and circular RNAs [circRNAs]) in the crosstalk between macrophages and tumor cells in hepatocellular carcinoma (HCC). These ncRNAs are derived from macrophages or tumor cells and act as oncogenes or tumor suppressors, contributing to tumor progression not only by regulating the physiological and pathological processes of tumor cells but also by controlling macrophage infiltration, activation, polarization, and function. Herein, we also explore the options available for clinical therapeutic strategies targeting crosstalk-related ncRNAs to treat HCC. A better understanding of the relationship between macrophages and tumor cells mediated by ncRNAs will uncover new diagnostic biomarkers and pharmacological targets in cancer.

Circ_0085315 promotes cell proliferation, invasion, and migration in colon cancer through miR-1200/MAP3K1 signaling pathway

Colon cancer (CC) is a common malignant tumor of the digestive tract. Circular RNAs (circRNAs) play important roles in the progression of CC. This study aimed to explore the role and mechanism of circRNA_0085315 in CC. In this study, we used qRT-PCR and Western blot assays to analyze the expressions of circRNA, miRNA, and mRNA as well as the expression of the related proteins. Luciferase reporter, RNA pull-down, and qRT-PCR assays were used to prove the relationship among circRNA, miRNA, and mRNA. CCK-8, colony formation, and transwell assays were used to perform the analysis of cell proliferation, migration, and invasion. Our results showed that the higher circRNA_0085315 expression led to the poorer prognosis of CC patients. The function of circRNA_0085315 as a ceRNA in competing with MAP3K1 mRNA to sponge miR-1200. CircRNA_0085315 sponged miR-1200 to promote cell proliferation, migration, and invasion and affected the expression of Ki67, MMP2, E-cadherin, and N-cadherin, but not circRNA_0085315-mut without the binding site of miR-1200. MAP3K1-overexpression or miR-1200 mimics prevented the suppression on the enhanced cell proliferation, migration, and invasion caused by circRNA_0085315-overexpression. circRNA_0085315 increased the phosphorylation levels of JNK, p38, and ERK1/2 by stimulating MAP3K1 up-regulation caused by miR-1200 inhibition. In conclusion, circRNA_0085315 serves as a ceRNA and promotes CC progression through the activation of the MAPK signaling pathway mediated via the miR-1200/MAP3K1 axis, suggesting that circRNA_0085315 may be a promising diagnostic and therapeutic target for CC.

Circular GOLPH3 RNA exerts oncogenic effects in vitro by regulating the miRNA-1299/LIF axis in oral squamous cell carcinoma

Circular RNAs, which are a novel subclass of noncoding RNAs, are reported to be involved in various biological processes. Aberrant expression of circular RNAs may promote cancer progression. The function of circular GOLPH3 RNA (circGOLPH3) in oral squamous cell carcinoma (OSCC) is unclear. In this study, the circGOLPH3 levels in OSCC cell lines were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Gain-of-function and loss-of-function experiments were performed to evaluate the roles of circGOLPH3 in OSCC. Cell counting kit 8, migration, and invasion assays were performed to determine the functions of circGOLPH3. The mechanism of circGOLPH3 in OSCC was investigated using qRT-PCR, western blotting, luciferase activity, and RNA pull-down analyses. Furthermore, the function of circGOLPH3 in vivo was evaluated. circGOLPH3 derived from GOLPH3 was mainly localized to the cytoplasm and exhibited high stability. The expression of circGOLPH3 was upregulated in OSCC cells. circGOLPH3 promoted the growth of OSCC in vitro and in vivo. Additionally, circGOLPH3 upregulated OSCC cell migration and invasion. Mechanistically, circGOLPH3 functioned as a microRNA sponge and downregulated miR-1299 expression. miR-1299 downregulated the expression of LIF by targeting its 3’-untranslated region. Inhibition of the circGOLPH3/miR-1299/LIF axis suppressed the growth, migration, and invasion of OSCC cells. These findings indicate that the circGOLPH3/miR-1299/LIF axis promotes OSCC cell growth, migration, and invasion and that this axis is a potential therapeutic target for OSCC.

Regulation of Pyroptosis by ncRNA: A Novel Research Direction

Pyroptosis is a novel form of programmed cell death (PCD), which is characterized by DNA fragmentation, chromatin condensation, cell swelling and leakage of cell contents. The process of pyroptosis is performed by certain inflammasome and executor gasdermin family member. Previous researches have manifested that pyroptosis is closely related to human diseases (such as inflammatory diseases) and malignant tumors, while the regulation mechanism of pyroptosis is not yet clear. Non-coding RNA (ncRNA) such as microRNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA) have been widely identified in the genome of eukaryotes and played a paramount role in the development of cell function and fate after transcription. Accumulating evidences support the importance of ncRNA biology in the hallmarks of pyroptosis. However, the associations between ncRNA and pyroptosis are rarely reviewed. In this review, we are trying to summarize the regulation and function of ncRNA in cell pyroptosis, which provides a new research direction and ideas for the study of pyroptosis in different diseases.

Identification of lncRNA/circRNA-miRNA-mRNA ceRNA Network as Biomarkers for Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) accounts for the majority of liver cancer, with the incidence and mortality rates increasing every year. Despite the improvement of clinical management, substantial challenges remain due to its high recurrence rates and short survival period. This study aimed to identify potential diagnostic and prognostic biomarkers in HCC through bioinformatic analysis.

Methods: Datasets from GEO and TCGA databases were used for the bioinformatic analysis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were carried out by WebGestalt website and clusterProfiler package of R. The STRING database and Cytoscape software were used to establish the protein-protein interaction (PPI) network. The GEPIA website was used to perform expression analyses of the genes. The miRDB, miRWalk, and TargetScan were employed to predict miRNAs and the expression levels of the predicted miRNAs were explored via OncomiR database. LncRNAs were predicted in the StarBase and LncBase while circRNA prediction was performed by the circBank. ROC curve analysis and Kaplan-Meier (KM) survival analysis were performed to evaluate the diagnostic and prognostic value of the gene expression, respectively.

Results: A total of 327 upregulated and 422 downregulated overlapping DEGs were identified between HCC tissues and noncancerous liver tissues. The PPI network was constructed with 89 nodes and 178 edges and eight hub genes were selected to predict upstream miRNAs and ceRNAs. A lncRNA/circRNA-miRNA-mRNA network was successfully constructed based on the ceRNA hypothesis, including five lncRNAs (DLGAP1-AS1, GAS5, LINC00665, TYMSOS, and ZFAS1), six circRNAs (hsa_circ_0003209, hsa_circ_0008128, hsa_circ_0020396, hsa_circ_0030051, hsa_circ_0034049, and hsa_circ_0082333), eight miRNAs (hsa-miR-150-5p, hsa-miR-19b-3p, hsa-miR-23b-3p, hsa-miR-26a-5p, hsa-miR-651-5p, hsa-miR-10a-5p, hsa-miR-214-5p and hsa-miR-486-5p), and five mRNAs (CDC6, GINS1, MCM4, MCM6, and MCM7). The ceRNA network can promote HCC progression via cell cycle, DNA replication, and other pathways. Clinical diagnostic and survival analyses demonstrated that the ZFAS1/hsa-miR-150-5p/GINS1 ceRNA regulatory axis had a high diagnostic and prognostic value.

Conclusion: These results revealed that cell cycle and DNA replication pathway could be potential pathways to participate in HCC development. The ceRNA network is expected to provide potential biomarkers and therapeutic targets for HCC management, especially the ZFAS1/hsa-miR-150-5p/GINS1 regulatory axis.

Circ_0036412 affects the proliferation and cell cycle of hepatocellular carcinoma via hedgehog signaling pathway

Background

Hepatocellular carcinoma (HCC), as the most common type of liver cancer, is characterized by high recurrence and metastasis. Circular RNA (circRNA) circ_0036412 was selected for studying the underlying mechanisms of HCC.

Methods

Quantitative real time-polymerase chain reaction (qRT-PCR) and western blot analyzed gene and protein expression. Functional experiments evaluated HCC cell proliferation, apoptosis and cell cycle in vitro. In vivo experiments detected HCC carcinogenesis in vivo. Fluorescence in situ hybridization (FISH) assays evaluated the subcellular distribution. Luciferase reporter, Chromatin immunoprecipitation (ChIP), DNA pulldown, RNA-binding protein immunoprecipitation (RIP), and RNA pulldown assays detected the underlying mechanisms.

Results

Circ_0036412 is overexpressed in HCC cells and features circular structure. PRDM1 activates circ_0036412 transcription to regulate the proliferation and cell cycle of HCC cells in vitro. Circ_0036412 modulates Hedgehog pathway. GLI2 propels HCC growth in vivo. Circ_0036412 up-regulates GLI2 expression by competitively binding to miR-579-3p, thus promoting the proliferation and inhibiting cell cycle arrest of HCC cells. Circ_0036412 stabilizes GLI2 expression by recruiting ELAVL1. Circ_0036412 propels the proliferation and inhibits cell cycle arrest of HCC cells in vitro through Hedgehog pathway.

Conclusions

Circ_0036412 affects the proliferation and cell cycle of HCC via Hedgehog signaling pathway. It offers an insight into the targeted therapies of HCC.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03305-x.

Identification of potentially functional circular RNAs hsa_circ_0070934 and hsa_circ_0004315 as prognostic factors of hepatocellular carcinoma by integrated bioinformatics analysis

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers worldwide, which has a high mortality rate and poor treatment outcomes with yet unknown molecular basis. It seems that gene expression plays a pivotal role in the pathogenesis of the disease. Circular RNAs (circRNAs) can interact with microRNAs (miRNAs) to regulate gene expression in various malignancies by acting as competitive endogenous RNAs (ceRNAs). However, the potential pathogenesis roles of the ceRNA network among circRNA/miRNA/mRNA in HCC are unclear. In this study, first, the HCC circRNA expression data were obtained from three Gene Expression Omnibus microarray datasets (GSE164803, GSE94508, GSE97332), and the differentially expressed circRNAs (DECs) were identified using R limma package. Also, the liver hepatocellular carcinoma (LIHC) miRNA and mRNA sequence data were retrieved from TCGA and differentially expressed miRNAs (DEMIs) and mRNAs (DEGs) were determined using the R DESeq2 package. Second, CSCD website was used to uncover the binding sites of miRNAs on DECs. The DECs' potential target miRNAs were revealed by conducting an intersection between predicted miRNAs from CSCD and downregulated DEMIs. Third, candidate genes were uncovered by intersecting targeted genes predicted by miRWalk and targetscan online tools with upregulated DEGs. The ceRNA network was then built using the Cytoscape software. The functional enrichment and the overall survival time of these potential targeted genes were analyzed, and a PPI network was constructed in the STRING database. Network visualization was performed by Cytoscape, and ten hub genes were detected using the CytoHubba plugin tool. Four DECs (hsa_circ_0000520, hsa_circ_0008616, hsa_circ_0070934, hsa_circ_0004315) were obtained and six miRNAs (hsa-miR-542-5p, hsa-miR-326, hsa-miR-511-5p, hsa-miR-195-5p, hsa-miR-214-3p, and hsa-miR-424-5p) which are regulated by the above DECs were identified. Then 543 overlapped genes regulated by six miRNAs mentioned above were predicted. Functional enrichment analysis showed that these genes are mostly associated with regulatory pathways in cancer. Ten hub genes (TTK, AURKB, KIF20A, KIF23, CEP55, CDC6, DTL, NCAPG, CENPF, PLK4) have been screened from the PPI network of the 204 survival-related genes. KIF20A, NCAPG, TTK, PLK4, and CDC6 were selected for the highest significance p-values. At the end, a circRNA-miRNA-mRNA regulatory axis was established for five final selected hub genes. This study implies the potential pathogenesis of the obtained network and proposes that the two DECs (has_circ_0070934 and has_circ_0004315) may be important prognostic markers for HCC.

Circ_0058063 contributes to cisplatin-resistance of bladder cancer cells by upregulating B2M through acting as RNA sponges for miR-335-5p

Bladder cancer (BC) is one of the most common malignant tumors of the urinary system, and cisplatin (CDDP) is a critical chemical drug for the treatment of BC. However, CDDP-resistance seriously limits the therapeutic efficacy of this drug for clinical utilization. Thus, identification of pivotal molecule targets that regulate CDDP-resistance in BC become urgent and necessary. In this study, we firstly identified a novel BC-associated circular RNA circ_0058063 that participates in the regulation of CDDP-resistance in BC. Specifically, circ_0058063 was significantly overexpressed in CDDP-resistant tissue and cells, in contrast with the corresponding CDDP-sensitive counterparts. Further loss-of-function experiments validated that downregulation of circ_0058063 suppressed cell proliferation and tumor growth, whereas induced cell apoptosis in the CDDP-resistant BC cells in vitro and in vivo. In addition, we disclosed that circ_0058063 acts as a sponge for miR-335-5p to positively regulate B2M expression, and further rescuing experiments verified that the enhancing effects of sh-circ_0058063 on CDDP-sensitivity in the CDDP-resistant BC cells were abrogated by silencing miR-335-5p. Taken together, our results demonstrated that circ_0058063 contributed to CDDP resistance of bladder cancer cells via sponging miR-335-5p, and B2M might be the downstream effector gene. This study firstly evidenced that targeting circ_0058063 might be an effective strategy to improve CDDP-sensitivity in BC.

Autophagy-associated circRNA circATG7 facilitates autophagy and promotes pancreatic cancer progression

Dysregulation of autophagy and circular RNAs (circRNAs) are involved in the pancreatic cancer (PC) progression. However, the regulatory network between circRNAs, autophagy, and PC progression remains unknown. Herein, we demonstrated that autophagy-associated circRNA circ-autophagy related 7 (circATG7) was elevated in PC tissues compared to adjacent tissues, and in PC cells treated with EBSS and hypoxia. circATG7 expression was positively associated with tumor diameter and lymph node invasion in patients with PC. circATG7 overexpression promoted PC cell proliferation, mobility, and autophagy in vitro, while circATG7 knockdown induced the opposite effects. ATG7 inhibition attenuated the effects of circATG7 on the biological functions of PC cells. CircATG7 is located in the cell cytoplasm and nucleus. Cytoplasmic circATG7 sponged miR-766-5p and decreased its expression, and increased the expression of ATG7, a target gene of miR-766-5p. Nuclear circATG7 acted as a scaffold to increase the interaction between the human antigen R protein and ATG7 mRNA and enhanced ATG mRNA stability. Furthermore, we demonstrated that circATG7 regulates PC cell proliferation and metastasis in vivo via ATG7-dependent autophagy. In conclusion, our results demonstrated that circATG7 accelerates PC progression via miR-766-5p/ATG7 and that HUR/ATG7 depends on autophagic flux. Thus, circATG7 may be a potential therapeutic target for PC.

Emerging roles of circular RNAs in liver cancer

Hepatocellular carcinoma and cholangiocarcinoma are the most common primary liver tumours, whose incidence and associated mortality have increased over recent decades. Liver cancer is often diagnosed late when curative treatments are no longer an option. Characterising new molecular determinants of liver carcinogenesis is crucial for the development of innovative treatments and clinically relevant biomarkers. Recently, circular RNAs (circRNAs) emerged as promising regulatory molecules involved in cancer onset and progression. Mechanistically, circRNAs are mainly known for their ability to sponge and regulate the activity of microRNAs and RNA-binding proteins, although other functions are emerging (e.g. transcriptional and post-transcriptional regulation, protein scaffolding). In liver cancer, circRNAs have been shown to regulate tumour cell proliferation, migration, invasion and cell death resistance. Their roles in regulating angiogenesis, genome instability, immune surveillance and metabolic switching are emerging. Importantly, circRNAs are detected in body fluids. Due to their circular structure, circRNAs are often more stable than mRNAs or miRNAs and could therefore serve as promising biomarkers - quantifiable with high specificity and sensitivity through minimally invasive methods. This review focuses on the role and the clinical relevance of circRNAs in liver cancer, including the development of innovative biomarkers and therapeutic strategies.

Construction and Comprehensive Analysis of a circRNA-miRNA-mRNA Regulatory Network to Reveal the Pathogenesis of Hepatocellular Carcinoma

Background: Circular RNAs (circRNAs) have been demonstrated to be closely related to the carcinogenesis of human cancer in recent years. However, the molecular mechanism of circRNAs in the pathogenesis of hepatocellular carcinoma (HCC) has not been fully elucidated. We aimed to identify critical circRNAs and explore their potential regulatory network in HCC.

Methods: The robust rank aggregation (RRA) algorithm and weighted gene co-expression network analysis (WGCNA) were conducted to unearth the differentially expressed circRNAs (DEcircRNAs) in HCC. The expression levels of DEcircRNAs were validated by quantitative real-time polymerase chain reaction (qRT-PCR). A circRNA-miRNA-mRNA regulatory network was constructed by computational biology, and protein-protein interaction (PPI) network, functional enrichment analysis, survival analysis, and infiltrating immune cells analysis were performed to uncover the potential regulatory mechanisms of the network.

Results: A total of 22 DEcircRNAs were screened out from four microarray datasets (GSE94508, GSE97332, GSE155949, and GSE164803) utilizing the RRA algorithm. Meanwhile, an HCC-related module containing 404 circRNAs was identified by WGCNA analysis. After intersection, only four circRNAs were recognized in both algorithms. Following qRT-PCR validation, three circRNAs (hsa_circRNA_091581, hsa_circRNA_066568, and hsa_circRNA_105031) were chosen for further analysis. As a result, a circRNA-miRNA-mRNA network containing three circRNAs, 17 miRNAs, and 222 mRNAs was established. Seven core genes (ESR1, BUB1, PRC1, LOX, CCT5, YWHAZ, and DDX39B) were determined from the PPI network of 222 mRNAs, and a circRNA-miRNA-hubgene network was also constructed. Functional enrichment analysis suggested that these seven hub genes were closely correlated with several cancer related pathways. Survival analysis revealed that the expression levels of the seven core genes were significantly associated with the prognosis of HCC patients. In addition, we also found that these seven hub genes were remarkably related to the infiltrating levels of immune cells.

Conclusion: Our research identified three pivotal HCC-related circRNAs and provided novel insights into the underlying mechanisms of the circRNA-miRNA-mRNA regulatory network in HCC.

Circ_0002623 promotes bladder cancer progression by regulating the miR-1276/SMAD2 axis

Circular RNAs (circRNAs) are key regulatory factors in the development of multiple cancers. This study is targeted at exploring the effect of circ_0002623 on bladder cancer (BCa) progression and its mechanism. Circ_0002623 was screened out by analyzing the expression profile of circRNAs in BCa tissues. Circ_0002623, miR-1276 and SMAD2 mRNA expression levels in clinical sample tissues and cell lines were detected through quantitative real-time polymerase chain reaction (qRT-PCR). After circ_0002623 was overexpressed or silenced in BCa cells, the cell proliferation, migration and cell cycle were evaluated by CCK-8, BrdU, Transwell assay and flow cytometry. Tumor xenograft model was used to validate the biological function of circ_0002623 in vivo. Bioinformatics analysis and dual-luciferase reporter gene assay were conducted for analyzing and confirming, respectively, the targeted relationship between circ_0002623 and miR-1276, as well as between miR-1276 and SMAD2. The regulatory effects of circ_0002623 and miR-1276 on the expression levels of TGF-β, WNT1 and SMAD2 in BCa cells were detected by Western blot. We reported that, in BCa tissues and cell lines, circ_0002623 was up-regulated, whereas miR-1276 was down-regulated. Circ_0002623 positively regulated BCa cell proliferation, migration and cell cycle progression. Additionally, circ_0002623 could competitively bind with miR-1276 to increase the expression of SMAD2, the target gene of miR-1276. Furthermore, circ_0002623 could regulate the expression of TGF-β and WNT1 via modulating miR-1276 and SMAD2. This study helps to better understand the molecular mechanism underlying BCa progression.

Exosomal hsa_circ_0004658 derived from RBPJ overexpressed-macrophages inhibits hepatocellular carcinoma progression via miR-499b-5p/JAM3

Macrophage-derived exosomes (Mφ-Exo) have multidimensional involvement in tumor initiation, progression, and metastasis, but their regulation in hepatocellular carcinoma (HCC) is not fully understood. RBPJ has been implicated in macrophage activation and plasticity. In this study we assess the role of exosomes derived from RBPJ-overexpressed macrophages (RBPJ^+/+ Mφ-Exo) in HCC. The circular RNA (circRNA) profiles in RBPJ^+/+ Mφ-Exo and THP-1-like macrophages (WT Mφ)-Exo was evaluated using circRNA microarray. CCK-8, Transwell, and flow cytometry analyses were used to evaluate the function of Mφ-Exo-circRNA on HCC cells. Luciferase reporter assays, RNA immunoprecipitation, and Pearson’s correlation analysis were used to confirm interactions. A nude mouse xenograft model was used to further analyze the functional significance of Mφ-Exo-cirRNA in vivo. Our results shown that hsa_circ_0004658 is upregulated in RBPJ^+/+ Mφ-Exo compared to WT Mφ-Exo. RBPJ^+/+ Mφ-Exo and hsa_circ_0004658 inhibits proliferation and promotes apoptosis in HCC cells, whereas hsa_circ_0004658 knockdown stimulated cell proliferation and migration but restrained apoptosis in vitro and promotes tumor growth in vivo. The effects of RBPJ^+/+ Mφ-Exo on HCC cells can be reversed by the hsa_circ_0004658 knockdown. Mechanistic investigations revealed that hsa_circ_0004658 acts as a ceRNA of miR-499b-5p, resulting in the de-repression of JAM3. These results indicate that exosome circRNAs secreted from RBPJ^+/+ Mφ inhibits tumor progression through the hsa_circ_0004658/miR-499b-5p/JAM3 pathway and hsa_circ_0004658 may be a diagnostic biomarker and potential target for HCC therapy.

Identification of Isthmin1 in the small annual fish, Nothobranchius guentheri, as a novel biomarker of aging and its potential rejuvenation activity

Isthmin 1 (Ism1) has been shown to play roles in multiple biological processes including morphogenesis, hematopoiesis, antiviral immune response and suppression of tumor growth. However, it remains unknown if it plays any role in aging process. Here we showed for the first time that Ism1 was a new age-related biomarker, which decreased with age in fish, mice and humans. Interestingly, Ism1 was also useful to measure the "rejuvenated" age of fish Nothobranchius guentheri reversed by salidroside treatment and temperature reduction, providing additional evidence that Ism1 was an aging biomarker. In addition, we clearly showed that dietary intake of recombinant Ism1 had little effects on the body length and weight of aging N. guentheri, but it retarded the onset of age-related biomarkers and prolonged both the maximum and median lifespan of the fish. We also showed that Ism1 exerted its rejuvenation activity via the enhancement of antioxidant system. Collectively, our results indicate that Ism1 is not only is a novel biomarker of aging but also a potential rejuvenation factor capable of reversing aging of N. guentheri.

Circ_0000212 affects proliferation, migration, invasion, apoptosis, and paclitaxel sensitivity of liver cancer cells by targeting miR-139-5p

BACKGROUND

Circ_0000212 is a newly discovered non-coding RNA whose high expression promotes the progression of colorectal cancer. However, the expression patterns and roles of circ_0000212 in liver cancer remain unknown.

AIM

To investigate the effect of circ_0000212 targeting miR-139-5p on cell proliferation, migration, invasion, apoptosis, and paclitaxel sensitivity in liver cancer.

METHODS

RT-qPCR was applied to detect the expression of circ_0000212 and miR-139-5p in liver cancer tissues and adjacent tissues. Pearson correlation analysis was performed to determine the relationship between circ_0000212 and miR-139-5p expression in liver cancer tissues. Dual luciferase reporter assay was used to verify the targeting relationship between circ_0000212 and miR-139-5p. Liver cancer HCC9204 cells were divided into a control group, circ_0000212 interference group, circ_0000212 interference + miR-139-5p inhibitor group, paclitaxel group, paclitaxel + circ_0000212 interference group, and paclitaxel + circ_0000212 interference + miR-139-5p inhibitor group. The rate of inhibited HCC9204 cells was detected using CCK-8 method; the number of clones formed by HCC9204 cells was calculated using colony formation assay; the apoptotic rate of HCC9204 cells was evaluated by flow cytometry; and the migration and invasion of HCC9204 cells were detected by Transwell assay.

RESULTS

Compared with adjacent tissue, the expression level of circ_0000212 in liver cancer tissue was significantly increased (P < 0.05), while the expression level of miR-139-5p was significantly decreased (P < 0.05). There was a negative correlation between the expression of circ_0000212 and miR-139-5p in liver cancer tissues. Circ_0000212 directly interacted with miR-139-5p. Compared with the control group, circ_0000212 expression in HCC9204 cells in the paclitaxel group was significantly reduced (P < 0.05), while miR-139-5p expression was significantly increased (P < 0.05). Compared with the control group, the numbers of clones formed and migrating and invading HCC9204 cells in the interference circ_0000212 group and paclitaxel group were significantly reduced (P < 0.05), and the inhibition rate and apoptosis rate were significantly increased (P < 0.05). Compared with the circ_0000212 interference group, the numbers of clone formed and migrating and invading HCC9204 cells in the interference circ_0000212+miR-139-5p inhibitor group were significantly increased (P < 0.05), and the inhibition rate and apoptosis rate were significantly reduced (P < 0.05). Compared with the paclitaxel group, the numbers of clones formed and migrating and invading HCC9204 cells in the paclitaxel + circ_0000212 interference group were significantly reduced (P < 0.05), and the inhibition rate and apoptosis rate were significantly increased (P < 0.05). Compared with the paclitaxel + circ_0000212 interference group, the numbers of clones formed and migrating and invading HCC9204 cells in the paclitaxel + circ_0000212 interference + miR-139-5p inhibitor group were significantly increased (P < 0.05), and the inhibition rate and apoptosis rate were significantly reduced (P < 0.05).

CONCLUSION

Interfering with circ_0000212 can inhibit cell proliferation, migration, and invasion, induce cell apoptosis, and increase its sensitivity to paclitaxel in liver cancer cells by targeting and up-regulating miR-139-5p.

Graph convolutional network approach to discovering disease-related circRNA-miRNA-mRNA axes

Non-coding RNAs are gaining prominence in biology and medicine, as they play major roles in cellular homeostasis among which the circRNA-miRNA-mRNA axes are involved in a series of disease-related pathways, such as apoptosis, cell invasion and metastasis. Recently, many computational methods have been developed for the prediction of the relationship between ncRNAs and diseases, which can alleviate the time-consuming and labor-intensive exploration involved with biological experiments. However, these methods handle ncRNAs separately, ignoring the impact of the interactions among ncRNAs on the diseases. In this paper we present a novel approach to discovering disease-related circRNA-miRNA-mRNA axes from the disease-RNA information network. Our method, using graph convolutional network, learns the characteristic representation of each biological entity by propagating and aggregating local neighbor information based on the global structure of the network. The approach is evaluated using the real-world datasets and the results show that it outperforms other state-of-the-art baselines on most of the metrics.

The Mechanism and Clinical Significance of Circular RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors worldwide. In view of the lack of early obvious clinical symptoms and related early diagnostic biomarkers with high specificity and sensitivity, most HCC patients are already at the advanced stages at the time of diagnosis, and most of them are accompanied by distant metastasis. Furthermore, the unsatisfactory effect of the follow-up palliative care contributes to the poor overall survival of HCC patients. Therefore, it is urgent to identify effective early diagnosis and prognostic biomarkers and to explore novel therapeutic approaches to improve the prognosis of HCC patients. Circular RNA (CircRNA), a class of plentiful, stable, and highly conserved ncRNA subgroup with the covalent closed loop, is dysregulated in HCC. Increasingly, emerging evidence have confirmed that dysregulated circRNAs can regulate gene expression at the transcriptional or post-transcriptional level, mediating various malignant biological behaviors of HCC cells, including proliferation, invasion, metastasis, immune escape, stemness, and drug resistance, etc.; meanwhile, they are regarded as potential biomarkers for early diagnosis and prognostic evaluation of HCC. This article reviews the research progress of circRNAs in HCC, expounding the potential molecular mechanisms of dysregulated circRNAs in the carcinogenesis and development of HCC, and discusses those application prospects in the diagnosis and prognosis of HCC.

[Correlation of peritumoral circWDR25 expression with the prognosis of patients with hepatocellular carcinoma after curative resection]

OBJECTIVE

To study the association between the expression of peritumoral circWDR25 (hsa-circRNA-0004310) secreted by hepatic stellate cells (HSCs) and the prognosis of the patients with hepatocellular carcinoma (HCC) after curative resection.

METHODS

HSCs cell line LX-2 was co-cultured separately with 3 liver cancer cell lines (Hep3B, SMMC-7721, and HCCLM3) in Transwell chambers to obtain tumor cell-activated HSCs. The supernatants of HSC cultures were collected to isolate the exosomes, from which total RNA was extracted to detect circRNA expression profile. We also collected specimens of paracancerous liver tissues from 288 HCC patients undergoing radical resection in our department from January, 2014 to October, 2015, and the expression levels of circWDR25 and α-SMA were detected with in situ hybridization. Log-rank test and Cox regression analysis were used for univariate and multivariate analysis of the factors affecting the patients' prognosis, respectively.

RESULTS

Gene expression profiling revealed that the expression of circWDR25 was the most obviously up-regulated in the exosomes isolated from tumor-activated LX-2 cells. The expression of peritumoral circWDR25 was positively correlated with HSCs adjacent to the cancer loci (r=0.156, P=0.008). Multivariate analysis showed that a preoperative AST level >36 g/L, multiple tumors, a tumor diameter >5 cm, HSC>70, and circWDR25>190 were independent risk factors affecting the overall survival of HCC patients after radical resection; a preoperative AST level >36 g/L, multiple tumors, a tumor diameter >5 cm, presence of tumor thrombus, HSC>70, and circWDR25>190 were all independent risk factors for tumor-free survival in patients with liver cancer.

CONCLUSION

Peritumoral circWDR25 and HSCs are factors affecting the prognosis of HCC patients after radical hepatectomy, and their high expression in the adjacent tissues is closely related to a poor prognosis of the patients.

Circular RNAs: characteristics, biogenesis, mechanisms and functions in liver cancer

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies globally. Despite aggressive and multimodal treatment regimens, the overall survival of HCC patients remains poor. MAIN: Circular RNAs (circRNAs) are noncoding RNAs (ncRNAs) with covalently closed structures and tissue- or organ-specific expression patterns in eukaryotes. They are highly stable and have important biological functions, including acting as microRNA sponges, protein scaffolds, transcription regulators, translation templates and interacting with RNA-binding protein. Recent advances have indicated that circRNAs present abnormal expression in HCC tissues and that their dysregulation contributes to HCC initiation and progression. Furthermore, researchers have revealed that some circRNAs might serve as diagnostic biomarkers or drug targets in clinical settings. In this review, we systematically evaluate the characteristics, biogenesis, mechanisms and functions of circRNAs in HCC and further discuss the current shortcomings and potential directions of prospective studies on liver cancer-related circRNAs.

CONCLUSION

CircRNAs are a novel class of ncRNAs that play a significant role in HCC initiation and progression, but their internal mechanisms and clinical applications need further investigation.

Effect of ISM1 on the Immune Microenvironment and Epithelial-Mesenchymal Transition in Colorectal Cancer

Background: An increasing number of studies have shown that Isthmin 1 (ISM1), a secreted protein, is important in tumorigenesis and invasion, including in colorectal cancer (CRC). However, the mechanisms are still unclear. This study aims to explore the function and prognosis capacity of ISM1 in CRC.

Methods: We investigated the expression of ISM1 in 18 CRC tissues vs. adjacent normal tissues from GSE50760, 473 CRC tissues vs. 41 normal tissues from The Cancer Genome Atlas (TCGA), and across gastrointestinal cancer types. Differences were further confirmed in CRC tissues via quantitative real-time polymerase chain reaction (qRT-PCR). Then, we analyzed correlations between clinicopathologic features and ISM1 expression, including prognostic prediction value, using the Kaplan–Meier method and multivariate Cox regression. Gene set enrichment analysis (GSEA) was performed to identify ISM1-related pathways. In vitro experiments were performed to verify the role of ISM1 in epithelial-mesenchymal transition (EMT) and CRC progression.

Results: Multiple datasets showed that ISM1 is upregulated in CRC tissues, which was validated. Patients with higher ISM1 expression had shorter overall survival (OS), and ISM1 expression served as an independent prognostic factor. Enrichment analysis showed that ISM1 upregulation was positively correlated with cancer-related pathways, such as EMT, hypoxia, and the Notch and KRAS signaling pathways. We were exclusively interested in the connection between ISM1 and EMT because 71% of genes in this pathway were significantly positively co-expressed with ISM1, which may account for why patients with higher ISM1 expression are prone to regional lymph node involvement and progression to advanced stages. In addition, we found that ISM1 was positively correlated with multiple immunosuppressive pathways such as IL2/STAT5, TNF-α/NF-κB, and TGF-β, and immune checkpoints, including PD-L1, PD-1, CTLA-4, and LAG3, which may account for upregulation of ISM1 in immunotherapy-resistant patients. Notably, through in vitro experiments, we found that ISM1 promoted EMT and colon cancer cell migration and proliferation.

Conclusion: ISM1 is critical for CRC development and progression, which enhances our understanding of the low response rate of CRC to immunotherapy via immunosuppressive signaling pathways.

Identification of RNA binding protein interacting with circular RNA and hub candidate network for hepatocellular carcinoma

The interaction between RNA binding protein (RBP) and circular RNA (circRNA) is important for the regulation of tumor progression. This study aimed to identify the RBP-circRNA network in hepatocellular carcinoma (HCC). 22 differentially expressed (DE) circRNAs in HCC were screened out from Gene Expression Omnibus (GEO) database and their binding RBPs were predicted by Circular RNA Interactome. Among them, 17 DERBPs, which were commonly dysregulated in HCC from The Clinical Proteomic Tumor Analysis Consortium (CPTAC), The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) projects, were utilized to construct the RBP-circRNA network. Through survival analysis, we found TARDBP was the only prognostic RBP for HCC in CPTAC, TCGA and ICGC projects. High expression of TARDBP was correlated with high grade, advanced stage and low macrophage infiltration of HCC. Additionally, gene set enrichment analysis showed that dysregulated TARDBP might be involved in some pathways related to the HCC pathogenesis. Therefore, a hub RBP-circRNA network was generated based on TARDBP. RNA immunoprecipitation and RNA pull-down confirmed that hsa_circ_0004913 binds to TARDBP. These findings indicated certain RBP-circRNA regulatory network potentially involved in the pathogenesis of HCC, which provides novel insights into the mechanism study and biomarker identification for HCC.