hsa_circ_0000092 promotes hepatocellular carcinoma progression through up-regulating HN1 expression by binding to microRNA-338-3p

HN1 is a novel dedifferentiation factor involved in regulating the cell cycle and microtubules in SH-SY5Y neuroblastoma cells

Hematological and neurological expressed 1 (HN1), encoding a small protein, has been recently explored in different cancers owing to its higher expression in tumor samples as compared to adjacent normal. It was discovered and subsequently named because of its higher expression in hematological and neurological tissues in developing mice. Following discovery, it was considered a neuronal regeneration or dedifferentiation-related gene. However, since then, it has not been characterized in neuroblastoma or differentiated neurons. SH-SY5Y cell line presents a unique model of neuroblastoma often utilized in neurobiology research. In this study, first, we employed bioinformatics analysis along with in vitro evaluation using normal and retinoic acid (RA)-differentiated SH-SY5Y cells to determine the responses of HN1 and its function. The analysis revealed that HN1 expression is higher in neuroblastoma and lower in differentiated neurons and Parkinson's disease as compared to appropriate controls. Since HN1 coexpression network in neuroblastoma is found to be enriched in cell-cycle-related pathways, we have shown that HN1 expression increases in S-phase and remains lower in the rest of the cell cycle phases. Moreover, HN1 expression is also correlated with the microtubule stability in SH-SY5Y cells, which was investigated with nocodazole and taxol treatments. HN1 overexpression increased the ratio of S-type cells (undifferentiated), indicating that it acts as a dedifferentiating factor in neuroblastoma cells. Moreover, cell cycle dynamics also changed upon HN1 overexpression with alternating effects on SH-SY5Y and RA-differentiated (N-type) cells. Therefore, HN1 is a potential cell cycle regulatory element in the development of neuroblastoma or dedifferentiation of neurons, which requires further studies to decipher its mechanistic role.

Whole-Transcriptome Analysis Reveals Potential CeRNA Regulatory Mechanism in Takifugu rubripes against Cryptocaryon irritans Infection

Cryptocaryon irritans (C. irritans) is a proto-ciliate parasite that infects marine fishes, including the cultured species Takifugu rubripes (T. rubripes), causing disease and potential mortality. In host organisms, infection by parasites triggers an immune response that is modulated by regulatory elements including proteins and non-coding RNAs. In this study, the whole transcriptome RNA sequencing of T. rubripes gill tissue before and after infection with C. irritans was performed to reveal the competitive endogenous RNA (ceRNA) regulatory network. Histomorphology revealed gill segment swelling and parasitic invasion in the infected group. The analysis identified 18 differentially expressed miRNAs (DEMs), 214 lncRNAs (DELs), 2501 genes (DEGs), and 7 circRNAs (DECs) in the infected group. Gene Ontology (GO) enrichment analysis revealed that these genes were notably enriched in the Wnt signaling pathway and mTOR signaling pathway. The co-expression networks (lncRNA/circRNA-miRNA-mRNA) were constructed based on correlation analysis of the differentially expressed RNAs. Further analysis suggested that the LOC105418663-circ_0000361-fru-miR-204a-fzd3a ceRNA axis was potentially involved in the regulation of immune responses against C. irritans infection. Finally, the expression levels of DEG, DEL, and DEM were validated. This study reveals the regulatory mechanism of a candidate ceRNA network, providing insights into the potential mechanism of T. rubripes' infection with C. irritans.

Hsa_circ_0000092 up-regulates IL24 by SMC1A to induce macrophages M2 polarization

Introduction

Hepatocellular carcinoma (HCC) as the malignant cancers with high morbidity. The EMT of HCC has closely linked to the metastasis and recurrence. Moreover, tumor-associated macrophages (TAMs) can interact with HCC cells in the immune microenvironment; the M2 polarization of TAMs enhance the HCC cells EMT. The mechanism between HCC cells and TAMs is still unclear and our study was aimed to uncover it.

Methods

We performed RT-qPCR and western to detach the RNA and protein expression. The relationship among has_circ_0000092, U2AF2, SMC1A and IL24 were revealed through mechanism experiments. Rescue assays were implemented to determine how circ_0000092 modulates M2 polarization of TAMs.

Results

As detected by RT-qPCR, has_circ_0000092 was with high expression in HCC cells and could recruit U2AF2 to promote transcription of SMC1A. Moreover, circ_0000092 could control macrophage M2 polarization via promoting IL24 expression in HCC cells.

Conclusion

To conclude, hsa_circ_0000092 can up-regulates IL24 by SMC1A to induce macrophages M2 polarization.

Exploring non-coding RNA mechanisms in hepatocellular carcinoma: implications for therapy and prognosis

Hepatocellular carcinoma (HCC) is a significant contributor to cancer-related deaths in the world. The development and progression of HCC are closely correlated with the abnormal regulation of non-coding RNAs (ncRNAs), such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). Important biological pathways in cancer biology, such as cell proliferation, death, and metastasis, are impacted by these ncRNAs, which modulate gene expression. The abnormal expression of non-coding RNAs in HCC raises the possibility that they could be applied as new biomarkers for diagnosis, prognosis, and treatment targets. Furthermore, by controlling the expression of cancer-related genes, miRNAs can function as either tumor suppressors or oncogenes. On the other hand, lncRNAs play a role in the advancement of cancer by interacting with other molecules within the cell, which, in turn, affects processes such as chromatin remodeling, transcription, and post-transcriptional processes. The importance of ncRNA-driven regulatory systems in HCC is being highlighted by current research, which sheds light on tumor behavior and therapy response. This research highlights the great potential of ncRNAs to improve patient outcomes in this difficult disease landscape by augmenting the present methods of HCC care through the use of precision medicine approaches.

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.

Circ_0091579 Knockdown Inhibited HCC Proliferation and Glutamine Metabolism Through miR-1270/YAP1 Axis

A growing number of studies have indicated that circRNAs play an important role in the progression of malignant tumors, including hepatocellular carcinoma (HCC). In this study, we designed to explore the abnormal expression of hsa_circ_0091579 (circ_0091579) and its role in the pathogenesis of HCC. In this study, the mRNA levels of circ_0091579, miR-1270, and Yes-associated protein (YAP1) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R and Actinomycin D were used to test the stability of circ_0091579. Cell Counting Kit-8 (CCK-8) was used to measure cell viability. Tubule formation assay was used to determine the effect of HCC cells on the number of tubes. Cell apoptosis was detected by flow cytometry. Western blot was used for the protein levels. Transwell and wound healing tests were used to measure the abilities of invasion and migration. The effect of circ_0091579 knockdown on tumor growth was verified in vivo by xenograft tumor assay and Immunohistochemistry (IHC) analysis. Dual-luciferase reporter or RIP assay was used to detect the relationship between miR-1270 and circ_0091579 or YAP1. Glutamine metabolism was determined by ELISA and western blot assays. In the present study, we found that circ_0091579 was upregulated in HCC tissues and cells. Inhibited circ_0091579 expression significantly suppressed proliferation and promoted apoptosis of HCC cells. Moreover, circ_0091579 knockdown inhibited tumor growth in vivo. Bioinformatic prediction and luciferase assay showed that circ_0091579 acted as a molecular sponge for miR-1270 and YAP1 was a target gene of miR-1270. MiR-1270 silencing could reverse the inhibitory effect of circ_0091579 knockdown on HCC progression, and YAP1 overexpression also could reverse the suppressive effect of circ_0091579 silencing on HCC progression. Meanwhile, miR-1270 inhibitor could invert the negative regulation effect of circ_0091579 silencing on YAP1 expression. Circ_0091579 promoted HCC progression by regulating the miR-1270/YAP1 axis, and our study might offer novel biomarkers and therapeutic targets for HCC.

Emerging Role of Circular RNAs in Hepatocellular Carcinoma Immunotherapy

Hepatocellular carcinoma (HCC) is a highly fatal malignancy with limited therapeutic options and high recurrence rates. Recently, immunotherapeutic agents such as immune checkpoint inhibitors (ICIs) have emerged as a new paradigm shift in oncology. ICIs, such as programmed cell death protein 1 (PD-1) inhibitors, have provided a new source of hope for patients with advanced HCC. Yet, the eligibility criteria of HCC patients for ICIs are still a missing piece in the puzzle. Circular RNAs (circRNAs) have recently emerged as a new class of non-coding RNAs that play a fundamental role in cancer pathogenesis. Structurally, circRNAs are resistant to exonucleolytic degradation and have a longer half-life than their linear counterparts. Functionally, circRNAs possess the capability to influence various facets of the tumor microenvironment, especially at the HCC tumor-immune synapse. Notably, circRNAs have been observed to control the expression of immune checkpoint molecules within tumor cells, potentially impeding the therapeutic effectiveness of ICIs. Therefore, this renders them potential cancer-immune biomarkers for diagnosis, prognosis, and therapeutic regimen determinants. In this review, the authors shed light on the structure and functional roles of circRNAs and, most importantly, highlight the promising roles of circRNAs in HCC immunomodulation and their potential as promising biomarkers and immunotherapeutic regimen determinants.

Targeting Non-Coding RNAs for the Development of Novel Hepatocellular Carcinoma Therapeutic Approaches

Hepatocellular carcinoma (HCC) remains a global health challenge, representing the third leading cause of cancer deaths worldwide. Although therapeutic advances have been made in the few last years, the prognosis remains poor. Thus, there is a dire need to develop novel therapeutic strategies. In this regard, two approaches can be considered: (1) the identification of tumor-targeted delivery systems and (2) the targeting of molecule(s) whose aberrant expression is confined to tumor cells. In this work, we focused on the second approach. Among the different kinds of possible target molecules, we discuss the potential therapeutic value of targeting non-coding RNAs (ncRNAs), which include micro interfering RNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules represent the most significant RNA transcripts in cells and can regulate many HCC features, including proliferation, apoptosis, invasion and metastasis. In the first part of the review, the main characteristics of HCC and ncRNAs are described. The involvement of ncRNAs in HCC is then presented over five sections: (a) miRNAs, (b) lncRNAs, (c) circRNAs, (d) ncRNAs and drug resistance and (e) ncRNAs and liver fibrosis. Overall, this work provides the reader with the most recent state-of-the-art approaches in this field, highlighting key trends and opportunities for more advanced and efficacious HCC treatments.

Review of novel functions and implications of circular RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequent malignancies, with high incidence and mortality. As the majority of HCC patients are diagnosed at an advanced stage and die of recurrence and metastasis, its pathology and new biomarkers are needed. Circular RNAs (circRNAs) are a large subclass of long non-coding RNAs (lncRNAs) with covalently closed loop structures and abundant, conserved, stable, tissue-specific expression in mammalian cells. CircRNAs exert multiple functions in HCC initiation, growth and progression, serving as promising biomarkers for diagnosis, prognosis and therapeutic targets for this disease. This review briefly describes the biogenesis and biological functions of circRNAs and elucidates the roles of circRNAs in the development and progression of HCC, especially regarding epithelial-mesenchymal transition (EMT), drug resistance and interactions with epigenetic modifications. In addition, this review highlights the implications of circRNAs as potential biomarkers and therapeutic targets for HCC. We hope to provide novel insight into the roles of circRNAs in HCC.

Circ-BICC1 Knockdown Alleviates Lipopolysaccharide (LPS)-Induced WI-38 Cell Injury Through miR-338-3p/MYD88 Axis

Circular RNAs (circRNAs) play important roles in human diseases, including infantile pneumonia. In this article, we aimed to investigate the functions of circ-BICC1 in lipopolysaccharide (LPS)-induced injury of WI-38 cells. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed for the levels of circ-BICC1, BICC1, microRNA-338-3p (miR-338-3p), and myeloid differentiation primary response 88 (MYD88). Cell Counting Kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, and flow cytometry analysis were conducted to evaluate cell viability, proliferation, and apoptosis, respectively. Enzyme-linked immunosorbent assay (ELISA) kits were used for the concentrations of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). The levels of oxidative stress markers were detected with commercial kits. Dual-luciferase reporter assay was adopted to analyze the interaction between circ-BICC1 and miR-338-3p, as well as MYD88 and miR-338-3p. Western blot assay was employed for the protein level of MYD88. Circ-BICC1 level was increased in pneumonia patients' blood samples and LPS-treated WI-38 cells. LPS treatment suppressed WI-38 cell viability and promoted cell apoptosis, inflammation, and oxidative stress. Circ-BICC1 knockdown reversed the effect of LPS-induced WI-38 cell injury. For mechanism analysis, circ-BICC1 could function as the sponge for miR-338-3p and miR-338-3p inhibition reversed the effect of circ-BICC1 knockdown on LPS-induced WI-38 cell injury. MYD88 was identified as the target of miR-338-3p. MiR-338-3p overexpression relieved LPS-induced injury of WI-38 cells, while the impact was abolished by elevating MYD88. Circ-BICC1 silencing remitted LPS-triggered WI-38 cell damage by adsorbing miR-338-3p and regulating MYD88.

Recent insights into the roles of circular RNAs in human brain development and neurologic diseases

Circular RNAs (circRNAs) are a novel class of non-coding RNAs. They are single-stranded RNA transcripts characterized with a closed loop structure making them resistant to degrading enzymes. Recently, circRNAs have been suggested with regulatory roles in gene expression involved in controlling various biological processes. Notably, they have demonstrated abundance, dynamic expression, back-splicing events, and spatiotemporally regulation in the human brain. Accordingly, they are expected to be involved in brain functions and related diseases. Studies in animals and human brain have revealed differential expression of circRNAs in brain compartments. Interestingly, contributing roles of circRNAs in the regulation of central nervous system (CNS) development have been demonstrated in a number of studies. It has been proposed that circRNAs play role in substantial neurological functions like neurotransmitter-associated tasks, neural cells maturation, and functions of synapses. Furthermore, 3 main pathways have been identified in association with circRNAs's host genes including axon guidance, Wnt signaling, and transforming growth factor beta (TGF-β) signaling pathways, which are known to be involved in substantial functions like migration and differentiation of neurons and specification of axons, and thus play role in brain development. In this review, we have an overview to the biogenesis, biological functions of circRNAs, and particularly their roles in human brain development and the pathogenesis of neurodegenerative diseases including Alzheimer's diseases, multiple sclerosis, Parkinson's disease and brain tumors.

Recent progress in molecular mechanisms of postoperative recurrence and metastasis of hepatocellular carcinoma

Hepatectomy is currently considered the most effective option for treating patients with early and intermediate hepatocellular carcinoma (HCC). Unfortunately, the postoperative prognosis of patients with HCC remains unsatisfactory, predominantly because of high postoperative metastasis and recurrence rates. Therefore, research on the molecular mechanisms of postoperative HCC metastasis and recurrence will help develop effective intervention measures to prevent or delay HCC metastasis and recurrence and to improve the long-term survival of HCC patients. Herein, we review the latest research progress on the molecular mechanisms underlying postoperative HCC metastasis and recurrence to lay a foundation for improving the understanding of HCC metastasis and recurrence and for developing more precise prevention and intervention strategies.

Circ_0049472 regulates the damage of Aβ-induced SK-N-SH and CHP-212 cells by mediating the miR-107/KIF1B axis

Alzheimer's disease (AD) is a neurodegenerative disease that seriously affects the life and health of the elderly. Studies have found that circular RNAs (circRNAs) are associated with human diseases, including AD. Hsa_circ_0049472 has been uncovered to be overexpressed in AD, but the role of circ_0049472 remains unclear. AD patients were recruited to collect cerebrospinal fluid (CSF) and serum samples. Amyloid beta (Aβ)-induced SK-N-SH and CHP-212 cells were used as the AD cell models in vitro. Quantitative real-time PCR (qRT-PCR) was used to assess the expression of circ_0049472, microRNA-107 (miR-107) and kinesin family member 1B (KIF1B). Cell counting kit-8 assay tested the cell viability, and flow cytometry measured cell apoptosis. The levels of proliferating cell nuclear antigen (PCNA), BCL2 Associated X (Bax) and kinesin family member 1B (KIF1B) protein were examined by western blot. In addition, the relative inflammatory cytokines (TNF-α, IL-6 and IL-1β) were detected by enzyme-linked immunosorbent assay (ELISA). The malondialdehyde (MDA) level and superoxide dismutase (SOD) activity were measured by relative kits. Dual-luciferase reporter assays and RNA pull-down assay verified the relationship between miR-107 and circ_0049472 or KIF1B. Circ_0049472 and KIF1B were overexpressed in AD patient-derived cerebrospinal fluid (CSF) and serum samples, as well as Aβ-induced SK-N-SH and CHP-212 cells. Silencing circ_0049472 promoted cell proliferation, and inhibited cell apoptosis in Aβ-induced SK-N-SH and CHP-212 cells. MiR-107 was a target of circ_0049472. MiR-107 silencing abolished the cell viability and apoptosis affected by down-regulation of circ_0049472 in Aβ-induced SK-N-SH and CHP-212 cells. Besides, miR-107 targeted KIF1B, and overexpressed KIF1B reverted miR-107 elevation-mediated effects on cell apoptosis, inflammation, and oxidative stress of Aβ-induced SK-N-SH and CHP-212 cells. Circ_0049472 modulated KIF1B by serving as a miR-107 decoy, thereby mediating Aβ-induced neurotoxicity, suggesting that circ_0049472 may be involved in AD pathogenesis.

Circ_0005918 Sponges miR-622 to Aggravate Intervertebral Disc Degeneration

Intervertebral discdegeneration (IDD) is the most common cause of lower back pain, but the exact molecular mechanism of IDD is still unknown. Recently, studies have shown that circular RNAs (circRNAs) regulate diverse biological procedures such as cell metastasis, growth, metabolism, migration, apoptosis, and invasion. We demonstrated that IL-1β and TNF-α induced circ_0005918 expression in the NP cell, and circ_0005918 was overexpressed in the IDD group compared with the control group. Moreover, the upregulated expression of circ_0005918 was associated with disc degeneration degree. The elevated expression of circ_0005918 promoted cell growth and ECM degradation, and it induced secretion of inflammatory cytokines including IL-1β, IL-6, and TNF-α. Moreover, we found that circ_0005918 sponged miR-622 in the NP cell. In addition, the exposure to IL-1β and TNF-α suppressed the expression of miR-622, which was downregulated in the IDD group compared with the control group. Furthermore, the downregulated expression of miR-622 was associated with disc degeneration degree. The expression level of miR-622 was negatively associated with circ_0005918 expression in the IDD group. In conclusion, circ_0005918 regulated cell growth, ECM degradation, and secretion of inflammatory cytokines by regulating miR-622 expression. These data suggested that circ_0005918 played important roles in the development of IDD via sponging miR-622.

Circular RNAs in hepatocellular carcinoma: Recent advances

Circular RNAs (circRNAs) have covalently closed loop structures at both ends, exhibiting characteristics dissimilar to those of linear RNAs. Emerging evidence suggests that aberrantly expressed circRNAs play crucial roles in hepatocellular carcinoma (HCC) by affecting the proliferation, apoptosis and invasive capacity of HCC cells. Certain circRNAs may be used as biomarkers to diagnose and predict the prognosis of HCC. Therefore, circRNAs are expected to become novel biomarkers and therapeutic targets for HCC. Herein, we briefly review the characteristics and biological functions of circRNAs, focusing on their roles in HCC to provide new insights for the early diagnosis and targeted therapy of HCC.

A Panel of E2F Target Gene Signature Predicting the Prognosis of Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the most malignant tumors, and the therapeutic effects of traditional treatments are poor. It is urgent to explore and identify new biomarkers and therapeutic targets to develop novel treatments which are individualized and effective. Three hallmarks, including E2F targets, G2M checkpoint and DNA repair, were collected by GSEA analysis. The panel of E2F-related gene signature consisted of five genes: HN1, KIF4A, CDCA3, CDCA8 and SSRP1. They had various mutation rates ranging from 0.8 to 5% in hepatocellular carcinoma, and patients with gene mutation had poorer prognosis. Among these genes, HN1 has the greatest mutation rate, and SSRP1 has the greatest impact on the model with a B (COX) value of 0.8842. Patients with higher expression of these genes had poorer prognosis. Kaplan-Meier curves in stratified survival analysis confirmed that patients with high risk scores had poor prognosis (p < 0.05). The results of univariate and multivariate COX survival analysis showed that risk score was closely related to the overall survival of patients with hepatocellular carcinoma. For clinical validation, we found that all the genes in the model were upregulated in hepatocellular carcinoma tissues compared to normal liver tissues, which was consistent with the previous results we obtained. Our study demonstrated that a panel of E2F target genes signature including five genes could predict the prognosis of hepatocellular carcinoma. This panel gene signature can facilitate the development of individualized and effective treatment for hepatocellular carcinoma.

High Expression of RRM1 Mediated by ncRNAs Correlates with Poor Prognosis and Tumor Immune Infiltration of Hepatocellular Carcinoma

Introduction

Hepatocellular carcinoma (HCC) is one of several tumors with poor prognosis and causes a significant social burden. A growing number of studies have shown that RRM1 plays a crucial role in the development and progression of multiple human cancers. However, the specific role and mechanism of RRM1 have not been fully defined in HCC.

Methods

TCGA and GTEx data were used for the first time to conduct a pan-cancer analysis of RRM1 expression and prognosis, and identified RRM1 as a possible potential oncogene in HCC. At the same time, a combination of analyses (including expression analysis, correlation analysis or survival analysis) identified non-coding RNAs (ncRNAs) that contribute to RRM1 overexpression.

Results

MIR4435-2HG/miR-22-3p and SNHG6/miR-101-3p were identified as the most promising RRM1 upstream ncRNA-related pathways in HCC. In addition, RRM1 levels were significantly and positively correlated with tumor immune cell infiltration, immune cell biomarker or immune checkpoint expression.

Conclusion

These results suggest that high expression of RRM1 mediated by ncRNAs is associated with poor prognosis and tumor immune infiltration in HCC.

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.

Circular RNA Circ_0000098 Elevates ALX4 Expression via Adsorbing miR-1204 to Inhibit the Progression of Hepatocellular Carcinoma

Background

Circular RNAs (CircRNAs) feature prominently in the progression of various cancers. However, the biological functions of many circRNAs in hepatocellular carcinoma (HCC) are far from fully clarified. This work is performed to decipher the function of circ_0000098 (circSLC30A7) in modulating the progression of HCC and its molecular mechanism.

Methods

Microarray data (GSE97332) were available from the Gene Expression Omnibus (GEO) database, and circRNA differentially expressed in HCC tissues was screened out by GEO2R tool. Circ_0000098, microRNA-1204 (miR-1204), and aristaless-like homeobox-4 (ALX4) mRNA expressions were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell counting kit-8 (CCK-8), scratch wound healing, and Transwell assays were adopted to determine proliferation, migration, and invasion of HCC cells. ALX4 protein, E-cadherin, N-cadherin, and Vimentin expressions were evaluated by Western blot. In addition, the targeting relationship between miR-1204 and circ_0000098 or ALX4 was studied with dual-luciferase reporter assay and RIP assay.

Results

Circ_0000098 expression level was markedly declined in HCC tissues and cells, and its underexpression was associated with larger tumor size of HCC patients. Knocking down circ_0000098 observably promoted the multiplication, migration, invasion, and epithelial-mesenchymal transition (EMT) of Huh7 and SMMC-7721 cells. Additionally, circ_0000098 was mainly distributed in the cytoplasm of HCC cells, and up-regulated ALX4 expression through competitively decoying miR-1204.

Conclusion

Circ_0000098, as a competitive endogenous RNA (ceRNA) of miR-1204, upregulates ALX4 expression and suppresses the growth, migration, invasion, and EMT of HCC cells.

CircRNA has_circ_0001806 promotes hepatocellular carcinoma progression via the miR-193a-5p/MMP16 pathway

Reportedly, circular RNAs (circRNAs) are crucial regulators in cancer progression. Nonetheless, the molecular mechanism of circRNAs in hepatocellular carcinoma (HCC) has not been fully clarified. Gene expression omnibus (GEO) database was employed to screen out the differentially expressed circRNAs in HCC. qRT-PCR and western blot were executed to detect circ_0001806 expression, miR-193a-5p expression, and MMP16 mRNA and protein expressions in HCC. The effect of circ_0001806 on HCC was analyzed by the CCK-8 method and Transwell experiment. RIP assay, pull-down experiment, and dual-luciferase reporter gene experiment were applied to validate the targeting relationships among circ_0001806, miR-193a-5p, and MMP16. Circ_0001806 was up-modulated in HCC tissues and cell lines. Knockdown of circ_0001806 impeded the multiplication, migration, and invasion of HCC cells. Circ_0001806 could up-regulate MMP16 expression through repressing miR-193a-5p, thereby facilitating the malignant biological behaviors of HCC. Circ_0001806 promoted HCC progression by regulating miR-193a-5p/MMP16 axis.

Long non-coding RNAs and circular RNAs in tumor angiogenesis: From mechanisms to clinical significance

Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) execute a wide array of functions in physiological and pathological processes, including tumor progression. Angiogenesis, an elaborate multistep process driving new blood vessel formation, accelerates cancer progression by supplying nutrients and energy. Dysregulated lncRNAs and circRNAs can reportedly impact cancer progression by influencing angiogenesis. However, the expanding landscape of lncRNAs and circRNAs in tumor progression-dependent angiogenesis remains largely unknown. This review summarizes the major functions of angiogenic lncRNAs (Angio-LncRs) and angiogenic circRNAs (termed Angio-CircRs) and their cancer mechanisms. Moreover, we highlight the commonalities of lncRNAs and circRNAs in epigenetic, transcriptional, and post-transcriptional regulation as well as illustrate how Angio-LncRs and Angio-CircRs induce cancer onset and progression. We also discuss their potential clinical applications in diagnosis, prognosis, and anti-angiogenic therapies.

The functional roles, cross-talk and clinical implications of m6A modification and circRNA in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related deaths worldwide. HCC has high rates of death and recurrence, as well as very low survival rates. N6-methyladenosine (m6A) is the most abundant modification in eukaryotic RNAs, and circRNAs are a class of circular noncoding RNAs that are generated by back-splicing and they modulate multiple functions in a variety of cellular processes. Although the carcinogenesis of HCC is complex, emerging evidence has indicated that m6A modification and circRNA play vital roles in HCC development and progression. However, the underlying mechanisms governing HCC, their cross-talk, and clinical implications have not been fully elucidated. Therefore, in this paper, we elucidated the biological functions and molecular mechanisms of m6A modification in the carcinogenesis of HCC by illustrating three different regulatory factors ("writer", "eraser", and "reader") of the m6A modification process. Additionally, we dissected the functional roles of circRNAs in various malignant behaviors of HCC, thereby contributing to HCC initiation, progression and relapse. Furthermore, we demonstrated the cross-talk and interplay between m6A modification and circRNA by revealing the effects of the collaboration of circRNA and m6A modification on HCC progression. Finally, we proposed the clinical potential and implications of m6A modifiers and circRNAs as diagnostic biomarkers and therapeutic targets for HCC diagnosis, treatment and prognosis evaluation.

Angiogenesis-related non-coding RNAs and gastrointestinal cancer

Gastrointestinal (GI) cancers are among the main reasons for cancer death globally. The deadliest types of GI cancer include colon, stomach, and liver cancers. Multiple lines of evidence have shown that angiogenesis has a key role in the growth and metastasis of all GI tumors. Abnormal angiogenesis also has a critical role in many non-malignant diseases. Therefore, angiogenesis is considered to be an important target for improved cancer treatment. Despite much research, the mechanisms governing angiogenesis are not completely understood. Recently, it has been shown that angiogenesis-related non-coding RNAs (ncRNAs) could affect the development of angiogenesis in cancer cells and tumors. The broad family of ncRNAs, which include long non-coding RNAs, microRNAs, and circular RNAs, are related to the development, promotion, and metastasis of GI cancers, especially in angiogenesis. This review discusses the role of ncRNAs in mediating angiogenesis in various types of GI cancers and looks forward to the introduction of mimetics and antagonists as possible therapeutic agents.

Circular RNAs in Hepatocellular Carcinoma: Emerging Functions to Clinical Significances

Hepatocellular carcinoma (HCC) is the most common primary cancer of the liver and carries high morbidity and mortality. Diagnosing HCC at an early stage is challenging. Therefore, finding new, highly sensitive and specific diagnostic biomarkers for the diagnosis and prognosis of HCC patients is extremely important. Circular RNAs (circRNAs) are a class of non-coding RNAs with covalently closed loop structures. They are characterized by remarkable stability, long half-life, abundance and evolutionary conservation. Recent studies have shown that many circRNAs are expressed aberrantly in HCC tissues and have important regulatory roles during the development and progression of HCC. Hence, circRNAs are promising biomarkers for the diagnosis and prognosis of HCC. This review: (i) summarizes the biogenesis, categories, and functions of circRNAs; (ii) focuses on current progress of dysregulated expression of circRNAs in HCC with regard to regulation of the tumor hallmarks, “stemness” of cancer cells, and immunotherapy; (iii) highlights circRNAs as potential biomarkers and therapeutic targets for HCC; and (iv) discusses some of the challenges, questions and future perspectives of circRNAs research in HCC.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

Molecular interactions of miR-338 during tumor progression and metastasis

Background

Cancer, as one of the main causes of human deaths, is currently a significant global health challenge. Since the majority of cancer-related deaths are associated with late diagnosis, it is necessary to develop minimally invasive early detection markers to manage and reduce mortality rates. MicroRNAs (miRNAs), as highly conserved non-coding RNAs, target the specific mRNAs which are involved in regulation of various fundamental cellular processes such as cell proliferation, death, and signaling pathways. MiRNAs can also be regulated by long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). They are highly stable in body fluids and have tumor-specific expression profiles, which suggest their suitability as efficient non-invasive diagnostic and prognostic tumor markers. Aberrant expression of miR-338 has been widely reported in different cancers. It regulates cell proliferation, migration, angiogenesis, and apoptosis in tumor cells.

Main body

In the present review, we have summarized all miR-338 interactions with other non-coding RNAs (ncRNAs) and associated signaling pathways to clarify the role of miR-338 during tumor progression.

Conclusions

It was concluded that miR-338 mainly functions as a tumor suppressor in different cancers. There were also significant associations between miR-338 and other ncRNAs in tumor cells. Moreover, miR-338 has a pivotal role during tumor progression using the regulation of WNT, MAPK, and PI3K/AKT signaling pathways. This review highlights miR-338 as a pivotal ncRNA in biology of tumor cells.

Exosomal Non-Coding RNAs: Regulatory and Therapeutic Target of Hepatocellular Carcinoma

Exosomes are small extracellular vesicles secreted by most somatic cells, which can carry a variety of biologically active substances to participate in intercellular communication and regulate the pathophysiological process of recipient cells. Recent studies have confirmed that non-coding RNAs (ncRNAs) carried by tumor cell/non-tumor cell-derived exosomes have the function of regulating the cancerous derivation of target cells and remodeling the tumor microenvironment (TME). In addition, due to the unique low immunogenicity and high stability, exosomes can be used as natural vehicles for the delivery of therapeutic ncRNAs in vivo. This article aims to review the potential regulatory mechanism and the therapeutic value of exosomal ncRNAs in hepatocellular carcinoma (HCC), in order to provide promising targets for early diagnosis and precise therapy of HCC.

Biological roles and potential clinical values of circular RNAs in gastrointestinal malignancies

Circular RNAs (circRNAs), a class of endogenous RNA molecules, are produced by alternative splicing of precursor RNA and are covalently linked at the 5' and 3' ends. Recent studies have revealed that dysregulated circRNAs are closely related to the occurrence and progression of gastrointestinal malignancies. Accumulating evidence indicates that circRNAs, including circPVT1, circLARP4, circ-SFMBT2, cir-ITCH, circRNA_100782, circ_100395, circ-DONSON, hsa_circ_0001368, circNRIP1, circFAT1(e2), circCCDC66, circSMARCA5, circ-ZNF652, and circ_0030235 play important roles in the proliferation, differentiation, invasion, and metastasis of cancer cells through a variety of mechanisms, such as acting as microRNA sponges, interacting with RNA-binding proteins, regulating gene transcription and alternative splicing, and being translated into proteins. With the characteristics of high abundance, high stability, extensive functions, and certain tissue-, time- and disease-specific expressions, circRNAs are expected to provide novel perspectives for the diagnoses and treatments of gastrointestinal malignancies.

hsa_circ_0001018 promotes papillary thyroid cancer by facilitating cell survival, invasion, G1/S cell cycle progression, and repressing cell apoptosis via crosstalk with miR-338-3p and SOX4

We identified a novel interactome, circ_0001018/miR-338-3p/SOX4, in papillary thyroid cancer (PTC), and we intended to confirm the regulatory relationship between the three and to study the effects of the three in PTC. The bioinformatics method was used to screen out the circular RNA and mRNA of interest. A cellular fractionation assay and fluorescence in situ hybridization (FISH) assay were conducted to prove that circ_0001018 and CCT4 (the host gene of circ_0001018) mRNA primarily localized in the cytoplasm of PTC cell lines. By qRT-PCR analysis, the expression of circ_0001018 and SOX4 mRNA was found upregulated while the expression of miR-338-3p was found downregulated in PTC tissues and cells. circ_0001018 silence significantly inhibited the tumor growth in xenografted nude mice. A series of cytological experiments such as a Cell Counting Kit-8 (CCK-8) assay, a 5-ethynyl-2′-deoxyuridine (EdU) assay, cell cycle profiling, wound healing, a transwell assay, and cell apoptosis were conducted and showed that circ_0001018 and SOX4 promoted cell proliferation, migration, and invasion, inhibited cell apoptosis, and reduced the cell cycle arrest at the G₁ phase in PTC cells. Compared with circ_0001018 and SOX4, miR-338-3p held the opposite function. The regulatory relationship between circ_0001018 and miR-338-3p, and between miR-338-3p and SOX4 mRNA, was validated using a luciferase reporter gene assay and/or RNA immunoprecipitation (RIP assay). Our findings showed that circ_0001018 acted as the tumor promoter via sponging miR-338-3p to elevate SOX4 expression level in PTC. Importantly, this novel circ_0001018/miR-338-3p/SOX4 axis has the potential to be considered as a therapy target for PTC.

Circular RNAs Sparkle in the Diagnosis and Theranostics of Hepatocellular Carcinoma

Exonic circular RNAs (circRNAs) are a novel subgroup of non-coding RNAs, which are generated by a back-splicing mechanism of the exons or introns. Unlike the linear RNA, circRNA forms a covalently closed loop, and it normally appears more abundant than the linear products of its host gene. Due to the relatively high specificity and stability of circular RNAs in tissues and body fluid, circular RNAs have attracted widely scientific interest for its potential application in cancer diagnosis and as a guide for preclinical therapy, especially for hard-to-treat cancers with high heterogeneity, such as hepatocellular carcinoma (HCC). Thus, we summarize the updated knowledge of circular RNAs, including the mechanism of the generation of endogenous circular RNAs and their regulatory, diagnostic, and therapeutic roles in HCC.

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.

Recent Update on the Role of Circular RNAs in Hepatocellular Carcinoma

After being overlooked for decades, circular RNAs (circRNAs) have recently generated considerable interest. circRNAs play a role in a variety of normal and pathological biological processes, including hepatocarcinogenesis. Many circRNAs contribute to hepatocarcinogenesis through sponging of microRNAs (miRs) and disruption of cellular signaling pathways that play a part in control of cell proliferation, metastasis and apoptosis. In most cases, overexpressed circRNAs sequester miRs to cause de-repressed translation of mRNAs that encode oncogenic proteins. Conversely, low expression of circRNAs has also been described in hepatocellular carcinoma (HCC) and is associated with inhibited production of tumor suppressor proteins. Other functions of circRNAs that contribute to hepatocarcinogenesis include translation of truncated proteins and acting as adapters to regulate influence of transcription factors on target gene expression. circRNAs also affect hepatocyte transformation indirectly. For example, the molecules regulate immune surveillance of cancerous cells and influence the liver fibrosis that commonly precedes HCC. Marked over- or under-expression of circRNA expression in HCC, with correlating plasma concentrations, has diagnostic utility and assays of these RNAs are being developed as biomarkers of HCC. Although knowledge in the field has recently surged, the myriad of described effects suggests that not all may be vital to hepatocarcinogenesis. Nevertheless, investigation of the role of circRNAs is providing valuable insights that are likely to contribute to improved management of a serious and highly aggressive cancer.

Hsa_circ_0006916 Knockdown Represses the Development of Hepatocellular Carcinoma via Modulating miR-599/SRSF2 Axis

Background

The aberrantly expressed circular RNAs (circRNAs) are implicated in the progression of hepatocellular carcinoma (HCC). CircRNA hsa_circ_0006916 (circ_0006916) is dysregulated in HCC, but the function and mechanism of this circRNA in HCC development remain uncertain.

Methods

Thirty paired HCC and normal tissues were collected. circ_0006916, microRNA (miR)-599 and serine/arginine rich splicing factor 2 (SRSF2) abundances were examined via quantitative reverse transcription polymerase chain reaction or Western blot. Cell viability, colony ability, migration, invasion, cell cycle and apoptosis were tested via cell counting kit-8, colony formation, wound healing analysis, transwell analysis, and flow cytometry. The interaction between miR-599 and circ_0006916 or SRSF2 was analyzed via dual-luciferase reporter and RNA immunoprecipitation analyses. The function of circ_0006916 on cell growth in vivo was analyzed via xenograft model.

Results

circ_0006916 expression was increased in HCC tissues and cell lines. circ_0006916 knockdown reduced cell viability, colony formation, migration and invasion and caused cell cycle arrest and apoptosis. miR-599 was targeted via circ_0006916, and miR-599 knockdown reversed the influence of circ_0006916 silence on HCC progression. SRSF2 was targeted via miR-599, and miR-599 overexpression suppressed cell viability, colony formation, migration and invasion and promoted cell cycle arrest and apoptosis via decreasing SRSF2. circ_0006916 could regulate SRSF2 expression via miR-599. circ_0006916 knockdown decreased HCC cell growth in the xenograft model.

Conclusion

circ_0006916 knockdown represses the progression of HCC via regulating miR-599 and SRSF2.

Circular RNAs in gastrointestinal cancer: Current knowledge, biomarkers and targeted therapy (Review)

Circular RNAs (circRNAs) are a type of endogenous non‑coding RNAs that are connected at the 3' and 5' ends by exon or intron cyclization, which forms a covalently closed loop. They are stable, well conserved, exhibit specific expression in mammalian cells and can function as microRNA (miRNA or miR) sponges to regulate the target genes of miRNAs, which influences biological processes. Such as tumor proliferation, invasion, metastasis, apoptosis and tumor stage. circRNAs represent promising candidates for clinical diagnosis and treatment. In the present review, the biogenesis, classification and functions of circRNAs in tumors are briefly summarized and discussed. In addition, the participation of circRNAs in signal transduction pathways regulating gastrointestinal cancer cellular functions is highlighted.

The Hsa_circ_0091579/miR-940/TACR1 Axis Regulates the Development of Hepatocellular Carcinoma

Purpose

Circular RNAs (circRNAs) play important roles in hepatocellular carcinoma (HCC) development. The circRNA hsa_circ_0091579 (circ_0091579) is dysregulated in HCC, while the mechanism of circ_0091579 in HCC development is largely unknown.

Patients and Methods

Thirty paired cancer and adjacent normal tissues were harvested from HCC patients. SNU-387 and Huh7 cells were cultured in this study. circ_0091579, microRNA-940 (miR-940) and tachykinin-1 receptor (TACR1) abundances were measured via quantitative reverse transcription-polymerase chain reaction or Western blot. Cell viability, migration, invasion, colony ability, cell cycle distribution and apoptosis were assessed via 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide, transwell assay, colony formation assay and flow cytometry. The interaction among circ_0091579, miR-940 and TACR1 was tested via dual-luciferase reporter analysis. The anti-HCC role of circ_0091579 knockdown in vivo was investigated using xenograft model.

Results

circ_0091579 expression was enhanced in HCC tissue samples and cells. circ_0091579 silence inhibited cell viability, migration, invasion and colony formation, induced cell cycle arrest at G0/G1 phase, and promoted apoptosis in HCC cells. miR-940 was targeted via circ_0091579 and miR-940 knockdown reversed the suppressive effect of circ_0091579 silence on HCC development. miR-940 targeted TACR1 to repress HCC development. circ_0091579 could regulate TACR1 expression by mediating miR-940. Down-regulation of circ_0091579 decreased xenograft tumor growth.

Conclusion

Knockdown of circ_0091579 repressed HCC development by mediating miR-940/TACR1 axis, indicating a new pathogenesis of HCC.

Knockdown of circ_HIPK3 inhibits tumorigenesis of hepatocellular carcinoma via the miR-582-3p/DLX2 axis

Hepatocellular carcinoma (HCC) is the most common type in the sub-classification of liver cancer. Circular RNAs (circRNAs) play a fundamental role in tumor occurrence and progression. This research aimed to investigate the role and molecular basis of circRNA homeodomain-interacting protein kinase 3 (circ_HIPK3) in HCC. Circ_HIPK3 and DLX2 levels were enhanced, and miR-582-3p level was reduced in HCC tissues and cells. Silencing of circ_HIPK3 impeded proliferation, migration and invasion and expedited apoptosis in HCC cells. Furthermore, circ_HIPK3 modulated HCC progression via sponging miR-582-3p, and miR-582-3p suppressed HCC progression via targeting DLX2. Moreover, circ_HIPK3 knockdown inhibited tumor growth in vivo. Circ_HIPK3 facilitated HCC progression by mediating miR-582-3p/DLX2 pathway, suggesting a new potential biomarker for HCC treatment.

Circular RNA circ_HN1 facilitates gastric cancer progression through modulation of the miR-302b-3p/ROCK2 axis

Gastric cancer (GC) is a malignant tumor with high morbidity and mortality in the world. Circular RNA hsa_circHN1_005 (circ_HN1), also termed as hsa_circ_0045602, is reported as an oncogene in GC. However, the molecular mechanism of circ_HN1 in GC development has not been fully explored. Here, we surveyed the regulatory mechanism of circ_HN1 in GC progression. The levels of circ_HN1, miR-302b-3p, and rho-associated coiled-coil containing protein kinase 2 (ROCK2) mRNA were measured by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation, apoptosis, colony formation, cell cycle progresion, migration, and invasion were determined by using cell counting, flow cytometry, colony formation, or transwell assays. Protein levels were detected with Western blotting. The relationship between circ_HN1 or ROCK2 and miR-302b-3p was verified via dual luciferase reporter or RNA immunoprecipitation (RIP) assays. The role of circ_HN1 in vivo was confirmed by xenograft assay. We observed that circ_HN1 and ROCK2 were upregulated while miR-302b-3p was downregulated in GC tissues and cells. Circ_HN1 silencing slowed tumor growth in vivo and impeded cell proliferation migration, invasion, and facilitated cell apoptosis in GC cells in vitro. Circ_HN1 sponged miR-302b-3p to regulate ROCK2 expression. MiR-302b-3p inhibitor reversed circ_HN1 silencing-mediated influence on the malignant behaviors of GC cells. Furthermore, ROCK2 overexpression restored miR-302b-3p mimic-mediated impacts on cell malignant behaviors in GC cells. In conclusion, circ_HN1 exerted an oncogenic role in GC through upregulating ROCK2 via sponging miR-302b-3p, offering evidence that circ_HN1 is a potential target for GC therapy.

Upregulated hsa_circ_0005785 Facilitates Cell Growth and Metastasis of Hepatocellular Carcinoma Through the miR-578/APRIL Axis

Although accumulating documents have expounded the pivotal position of circular RNAs (circRNAs) in hepatocarcinogenesis and progression, the overwhelming majority of their functions and molecular mechanisms in hepatocellular carcinoma (HCC) are elusive. Herein, we explored the functions and potential mechanisms of hsa_circ_0005785 in HCC, which was aberrantly overexpressed in HCC and related to HCC patients' TNM stage and overall survival. Moreover, hsa_circ_0005785 depletion could repress proliferation and metastasis of the HCC cell in vitro, lead to cell apoptosis and cell-cycle arrest, and restrain HCC cell growth in vivo. Furthermore, mechanism analyses discovered that hsa_circ_0005785 adsorbed miR-578 by playing a miRNA sponge role, which resulted in the derepression of a proliferation-inducing ligand (APRIL) expression, miR-578's mRNA target. Besides, hsa_circ_0005785 reversed the suppressive influence of miR-578 on HCC and accelerated tumor malignant progression through the miR-578/APRIL axis. Taken together, our current study revealed an oncogenic role of hsa_circ_0005785 in the tumorigenesis of HCC. Moreover, targeting to the hsa_circ_0005785/miR-578/APRIL regulatory pathway might be a promising diagnostic and therapeutic strategy for HCC clinical practice.

Circular RNA 103862 Promotes Proliferation and Invasion of Laryngeal Squamous Cell Carcinoma Cells Through the miR-493-5p/GOLM1 Axis

Accumulating evidence suggests that circular RNAs (circRNAs) may be a key contributor to oncogenesis. Yet, the function of circRNAs in laryngeal squamous cell carcinoma (LSCC) is still not clear. In this study, we examined the function of circRNA_103862 in LSCC progression by analyzing the tissue specimens collected from a patient with LSCC by using different LSCC cell models in vitro and an LSCC xenograft model in nude mice. We found that circRNA_103862 was frequently upregulated in the tissues of LSCC and was correlated with metastasis and prognosis of LSCC patients. Furthermore, circRNA_103862 downregulation could reduce proliferation, migration, and invasion ability of LSCC cells. In terms of mechanism exploration, miR-493-5p was sponged by circRNA_103862. Rescue experiments also showed that circRNA_103862 could achieve a carcinogenic effect by regulating miR-493-5p. Moreover, a luciferase reporter analysis showed that Golgi membrane protein 1 (GOLM1) is a downstream effector of miR-493-5p. In conclusion, our data suggested that circRNA_103862 promotes the proliferation of LSCC through targeting the miR-493-5p/GOLM1 axis, and it might serve as a potential prognosis marker and therapy target for LSCC.

Circular RNA is a popular molecule in tumors of the digestive system (Review)

Most tumors of the digestive system, including esophageal, gastric, liver and colorectal cancer, are malignant tumors that are associated with rates of high morbidity and mortality. The lack of effective methods for early diagnosis is an important cause of poor prognosis for these malignancies. Circular RNAs (circRNAs) belong to a family of endogenous, covalently closed non‑coding RNAs that are characterized as having no 5' cap structures or 3' poly‑A tails. Shortly following discovery, circRNAs were considered to be a product of mis‑splicing and have no significant biological function. However, in recent years, accumulating evidence is demonstrating that they serve key roles in tumorigenesis and have the potential to serve as diagnostic markers. The present article summarizes the biogenesis and function of circRNAs and reviews their role in seven common types of tumor of the digestive system whilst exploring their potential as tumor markers and the significant roles they can serve in the digestive system, in addition to providing a referencing point for future studies of digestive system malignancies.

circRNA hsa_circ_104566 Sponged miR-338-3p to Promote Hepatocellular Carcinoma Progression

Circular RNAs (circRNAs) could sponge micro-RNAs (miRNAs) to regulate tumor progression of hepatocellular carcinoma (HCC). Hsa_circ_104566 contributes to papillary thyroid carcinoma progression. However, the tumorigenic mechanism of hsa_circ_104566 on HCC remains enigmatic. The role of hsa_circ_104566 on HCC was therefore evaluated in this study. First, the high expression of hsa_circ_104566 was found in HCC tissues, which was significantly associated with poor prognosis in HCC patients. Second, Hsa_circ_104566 promoted HCC progression by decreasing apoptosis and E-cadherin, while increasing cell viability, proliferation, migration, invasion, and N-cadherin. On the other hand, HCC progression was suppressed by knockdown of hsa_circ_104566. Hsa_circ_104566 could target miR-338-3p, and its expression was negatively correlated with miR-338-3p in HCC patients. Moreover, miR-338-3p suppressed protein expression of Forkhead box protein 1 (FOXP1) and had a negative correlation with FOXP1 in HCC patients. Functional assay further indicated that the promotion of HCC progression by hsa_circ_104566 was reversed by miR-338-3p, and miR-338-3p inhibitor could counteract the effect of hsa_circ_104566 knockdown on the suppression of HCC progression. In vivo assay indicated that hsa_circ_104566 knockdown suppressed HCC tumor growth and metastasis. In conclusion, hsa_circ_104566 sponged miR-338-3p to promote HCC progression, providing a potential therapeutic target for cancer intervention.