Construct a circRNA/miRNA/mRNA regulatory network to explore potential pathogenesis and therapy options of clear cell renal cell carcinoma

Circ-IP6K2 suppresses tumor progression by modulating the miR-1292-5p/CAMK2N1 signal in clear cell renal cell carcinoma

Renal cell carcinoma (RCC) is a malignant tumor originating from the epithelial cells of the renal tubules. The clear cell RCC subtype is closely linked to a poor prognosis due to its rapid progression. Circular RNA (circRNA) is a novel class of regulatory RNA molecules that play a role in the development of ccRCC, although their functions have not been fully elucidated. In this study, we identified a significant downregulation of circ-IP6K2 in ccRCC tissues based on data from the GSE100186 dataset. The decreased expression of circ-IP6K2 correlated with the progression of TNM stage and histological grade, and was also associated with decreased overall survival rates in ccRCC patients. Moreover, our findings revealed that circ-IP6K2 expression suppressed proliferation, migration, and invasion capabilities in vitro, and inhibited xenograft growth in vivo. Mechanistically, circ-IP6K2 acted as a sponge for miR-1292-5p in ccRCC cells, which in turn targeted the 3'UTR of CAMK2N1, leading to a decrease in its expression. CAMK2N1 was identified as a tumor suppressor that negatively regulated the β-catenin/c-Myc oncogenic signaling pathway. Additionally, we confirmed a positive correlation between the expression of circ-IP6K2 and CAMK2N1 in ccRCC. Circ-IP6K2 functions to impede the progression of ccRCC by modulating the miR-1292-5p/CAMK2N1 axis. These findings shed new light on the molecular mechanisms driving ccRCC progression and suggest potential therapeutic targets for the treatment of ccRCC.

CircPRELID2 functions as a promoter of renal cell carcinoma through the miR-22-3p/ETV1 cascade

BACKGROUND

Emerging evidence has indicated that a number of circular RNAs (circRNAs) participate in renal cell carcinoma (RCC) carcinogenesis. Nevertheless, the activity and molecular process of circPRELID2 (hsa_circ_0006528) in RCC progression remain unknown.

METHODS

CircPRELID2, miR-22-3p and ETS variant 1 (ETV1) levels were gauged by qRT-PCR. Effect of the circPRELID2/miR-22-3p/ETV1 axis was evaluated by detecting cell growth, motility, and invasion. Immunoblotting assessed related protein levels. The relationships of circPRELID2/miR-22-3p and miR-22-3p/ETV1 were confirmed by RNA immunoprecipitation (RIP), luciferase reporter or RNA pull-down assay.

RESULTS

CircPRELID2 was up-regulated in RCC. CircPRELID2 silencing suppressed RCC cell growth, motility and invasion. Moreover, circPRELID2 silencing weakened M2-type macrophage polarization in THP1-induced macrophage cells. CircPRELID2 sequestered miR-22-3p, and circPRELID2 increased ETV1 expression through miR-22-3p. Moreover, the inhibitory impact of circPRELID2 silencing on RCC cell malignant behaviors was mediated by the miR-22-3p/ETV1 axis. Furthermore, circPRELID2 knockdown in vivo hampered growth of xenograft tumors.

CONCLUSION

Our study demonstrates that circPRELID2 silencing can mitigate RCC malignant development through the circPRELID2/miR-22-3p/ETV1 axis, highlighting new therapeutic targets for RCC treatment.

Cirscan: a shiny application to identify differentially active sponge mechanisms and visualize circRNA-miRNA-mRNA networks

BACKGROUND

Non-coding RNAs represent a large part of the human transcriptome and have been shown to play an important role in disease such as cancer. However, their biological functions are still incompletely understood. Among non-coding RNAs, circular RNAs (circRNAs) have recently been identified for their microRNA (miRNA) sponge function which allows them to modulate the expression of miRNA target genes by taking on the role of competitive endogenous RNAs (ce-circRNAs). Today, most computational tools are not adapted to the search for ce-circRNAs or have not been developed for the search for ce-circRNAs from user's transcriptomic data.

RESULTS

In this study, we present Cirscan (CIRcular RNA Sponge CANdidates), an interactive Shiny application that automatically infers circRNA-miRNA-mRNA networks from human multi-level transcript expression data from two biological conditions (e.g. tumor versus normal conditions in the case of cancer study) in order to identify on a large scale, potential sponge mechanisms active in a specific condition. Cirscan ranks each circRNA-miRNA-mRNA subnetwork according to a sponge score that integrates multiple criteria based on interaction reliability and expression level. Finally, the top ranked sponge mechanisms can be visualized as networks and an enrichment analysis is performed to help its biological interpretation. We showed on two real case studies that Cirscan is capable of retrieving sponge mechanisms previously described, as well as identifying potential novel circRNA sponge candidates.

CONCLUSIONS

Cirscan can be considered as a companion tool for biologists, facilitating their ability to prioritize sponge mechanisms for experimental validations and identifying potential therapeutic targets. Cirscan is implemented in R, released under the license GPL-3 and accessible on GitLab ( https://gitlab.com/geobioinfo/cirscan_Rshiny ). The scripts used in this paper are also provided on Gitlab ( https://gitlab.com/geobioinfo/cirscan_paper ).

Analysis of Potential Circular RNAs in Regulating Imatinib Resistance of Gastrointestinal Stromal Tumor

INTRODUCTION

Recent studies have found that circular RNA is an abundant RNA species that belongs to part of the competing endogenous RNA network (ceRNA), which was proven to play an important role in the development, diagnosis and progress of diseases. However, the function of circRNAs in imatinib resistance in Gastrointestinal stromal tumor (GIST) are poorly understood so for. The present study aimed to screen and predict the potential circRNAs in imatinib resistance of GIST using microarray analysis.

METHODS

We determined the expression of circular RNAs in paired normal gastric tissues (N), primary GIST (gastrointestinal stromal tumor) tissues (YC) and imatinib mesylate secondary resistance GIST tissues (C) with microarray and predicted 8677 dysregulated circular RNAs.

RESULTS

Compared with the YC group, we identified 15 circRNAs that were up-regulated and 8 circRNAs that were down-regulated in the C group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that these host linear transcripts that differentially express circular RNAs are involved in many key biological pathways, predicting the potential tumor-genesis and drug resistance mechanismrelated to HIF-1 pathway, later we draw the cirRNA-miRNA-mRNA network involved in the HIF-1 pathway and found several dysregulated circRNAs and the relationship between circRNA-miRNAs-mRNA, such as circRNA_06551, circRNA_14668, circRNA_04497, circRNA_08683, circRNA_09923(Green, down-regulation) and circRNA_23636, circRNA_15734 (Red, up-regulation).

CONCLUSION

Taken together, we identified a panel of dysregulated circRNAs that may be potential biomarkers even therapy relevant to the GIST, especially imatinib secondary resistance GIST.

The Mechanism of Oxymatrine Targeting miR-27a-3p/PPAR-γ Signaling Pathway through m6A Modification to Regulate the Influence on Hemangioma Stem Cells on Propranolol Resistance

OBJECTIVE

The proliferation and migration of hemangioma stem cells (HemSCs) induced apoptosis and adipose differentiation as well as increased the sensitivity of HemSCs to propranolol (PPNL). MiR-27a-3p negatively controlled the peroxisome-proliferator-activated receptor γ (PPAR-γ) level, counteracting the effect of PPAR-γ on HemSC progression and PPNL resistance. OMT accelerated HemSC progression and adipocyte differentiation via modulating the miR-27a-3p/PPAR-γ axis, inhibiting HemSC resistance to PPNL. In tumor-forming experiments, OMT exhibited a dose-dependent inhibitory effect on the volume of IH PPNL-resistant tumors, which was partially dependent on the regulation of m6A methylation transfer enzyme METTL3 and the miR-27a-3p/PPAR-γ axis, thereby inducing apoptosis.

CONCLUSIONS

We conclude that OMT regulates IH and influences PPNL resistance via targeting the miR-27a-3p/PPAR-γ signaling pathway through m6A modification.

MicroRNAs as Potential Regulators of GSK-3β in Renal Cell Carcinoma

The prognosis of patients with advanced renal cell carcinoma (RCC) has improved with newer therapies, including molecular-targeted therapies and immuno-oncology agents. Despite these therapeutic advances, many patients with metastatic disease remain uncured. Inhibition of glycogen synthase kinase-3β (GSK-3β) is a promising new therapeutic strategy for RCC; however, the precise regulatory mechanism has not yet been fully elucidated. MicroRNAs (miRNAs) act as post-translational regulators of target genes, and we investigated the potential regulation of miRNAs on GSK-3β in RCC. We selected nine candidate miRNAs from three databases that could potentially regulate GSK-3β. Among these, hsa-miR-4465 (miR-4465) was downregulated in RCC cell lines and renal cancer tissues. Furthermore, luciferase assays revealed that miR-4465 directly interacted with the 3' untranslated region of GSK-3β, and Western blot analysis showed that overexpression of miR-4465 significantly decreased GSK-3β protein expression. Functional assays showed that miR-4465 overexpression significantly suppressed cell invasion of A498 and Caki-1 cells; however, cell proliferation and migration were suppressed only in Caki-1 and A498 cells, respectively, with no effect on cell cycle and apoptosis. In conclusion, miR-4465 regulates GSK-3β expression but does not consistently affect RCC cell function as a single molecule. Further comprehensive investigation of regulatory networks is required in this field.

Hsa_circ_0057105 modulates a balance of epithelial-mesenchymal transition and ferroptosis vulnerability in renal cell carcinoma

BACKGROUND

The incidence of renal cell carcinoma (RCC) has increased in recent years. Metastatic RCC is common and remains a major cause of mortality. A regulatory role for circular RNAs (circRNAs) in the occurrence and progression of RCC has been identified, but their function, molecular mechanisms, and potential clinical applications remain poorly understood.

METHODS

High-throughput RNA sequencing was used to explore the differential expression of circRNAs and their related pathways in RCC patients. Transwell and CCK-8 assays were used to assess the function of hsa_circ_0057105 in RCC cells. The clinical relevance of hsa_circ_0057105 was evaluated in a cohort of RCC patients. The hsa_circ_0057105 regulatory axis was defined using RNA pull-down, luciferase reporter assays, and fluorescence in situ hybridization assays, and the in vivo effect of hsa_circ_0057105 was validated using animal experiments.

RESULTS

Single-sample gene set enrichment analysis and correlation analysis of RNA-seq data showed that hsa_circ_0057105 was potentially oncogenic and may serve to regulate epithelial-mesenchymal transition (EMT) activation in RCC. Hsa_circ_0057105 expression was associated with advanced TNM stages and was an independent prognostic factor for poor RCC patient survival. Phenotypic studies show that hsa_circ_0057105 can enhance the migration and invasion abilities of RCC cells. Further, hsa_circ_0057105 was shown to inhibit the expression of miR-577, a miRNA that regulated the expression of both COL1A1, which induced EMT activation, and VDAC2, which modulated ferroptosis sensitivity. The dual regulatory roles of hsa_circ_0057105 on EMT and ferroptosis sensitivity were verified using rescue experiments. Animal studies confirmed that hsa_circ_0057105 increased the metastatic ability and ferroptosis sensitivity of RCC cells in vivo.

CONCLUSIONS

In RCC, hsa_circ_0057105 regulates COL1A1 and VDAC2 expression through its sponge effect on miR-577, acting like a 'double-edged sword'. These findings provide new insight into the relationship between EMT and ferroptosis in RCC and provide potential biomarkers for RCC surveillance and treatment.

Circ_TNFRSF21 promotes cSCC metastasis and M2 macrophage polarization via miR-214-3p/CHI3L1

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is a highly invasive disease with the potential to metastasize and cause fatality. Therefore, it is crucial to understand the mechanism behind cSCC in order to devise effective strategies to combat this disease.

OBJECTIVE

We investigated the function of circ_TNFRSF21/miR-214-3p/CHI3L1 axis in cSCC.

METHODS

The features of circ_TNFRSF21 was characterized using Sanger sequencing, and RNase R/actinomycin D treatment. Genes and M1/M2 markers levels were assessed by qRT-PCR and IHC. The proliferation, migration, and invasion of cells were evaluated by CCK-8, colony formation, EdU incorporation, and transwell assays. Tumor growth and metastasis in vivo were evaluated by nude mouse xenograft model. Interactions of circ_TNFRSF21/miR-214-3p and miR-214-3p/CHI3L1 were validated by RNA immunoprecipitation and dual luciferase assay.

RESULTS

Circ_TNFRSF21 and CHI3L1 expression were elevated in both human cSCC tissues and cells, whereas miR-214-3p was reduced. Circ_TNFRSF21 silencing or miR-214-3p overexpression suppressed cSCC cell proliferation, migration, invasion, and M2 macrophage polarization. Circ_TNFRSF21 functioned as a sponge for miR-214-3p while miR-214-3p directly targeted CHI3L1. Knockdown of miR-214-3p reversed the effects of circ_TNFRSF21 knockdown on cSCC development, while CHI3L1 upregulation reversed the effects of miR-214-3p overexpression. Furthermore, knockdown of circ_TNFRSF21 inhibited cSCC tumor growth and metastasis in vivo.

CONCLUSION

Circ_TNFRSF21 plays a significant role in cSCC progression by enhancing cell proliferation, migration, invasion, and M2 macrophage polarization through inhibiting miR-214-3p and subsequent disinhibition of CHI3L1. These findings deepen our understanding of the molecular mechanism of cSCC and propose the circ_TNFRSF21/miR-214-3p/CHI3L1 axis as promising diagnosis markers or therapeutic targets for cSCC.

Targeting a novel circITCH/miR-421/BTG1 axis is effective to suppress the malignant phenotypes in hepatocellular carcinoma (HCC) cells

Circular RNA-based competing endogenous RNA (ceRNA) networks contribute to the initiation and development of various types of cancer, including hepatocellular carcinoma (HCC). Although a novel circular RNA itchy E3 ubiquitin protein ligase (circITCH) is identified as a tumor suppressor in HCC, its detailed molecular mechanisms have not been fully delineated. The present study was designed to resolve this issue, and we firstly verified that circITCH suppressed the malignant phenotypes in HCC cells by regulating a novel miR-421/B-cell translocation gene 1 (BTG1) axis. Specifically, through performing the Real-Time qPCR analysis, we noticed that circITCH expression in HCC tumor tissues or cell lines were significantly lower than that in adjacent normal tissues or normal hepatocytes, and the expression levels of circITCH were negatively correlated with tumor size and TNM stage in HCC patients. Next, our functional experiments confirmed that overexpression of circITCH induced cell cycle arrest and apoptosis, and reduced cell viability and colony forming ability in Hep3B and Huh7 cells. Mechanically, bioinformatics analysis, RNA immunoprecipitation and luciferase reporter assay demonstrated that circITCH served as RNA sponges for miR-421 to elevate BTG1 levels in HCC cells. The rescuing experiments verified that upregulation of miR-421 promoted cell viability and colony formation, and reduced apoptosis, which were abrogated by overexpression of circITCH or BTG1. In conclusion, this study identified a novel circITCH/miR-421/BTG1 axis that restrained the development of HCC, and our findings provided novel biomarkers for the treatment of this disease.

A novel circular RNA circNLRP3 alleviated ricin toxin-induced TNF-α production through sponging miR-221-5p

Acting as microRNA (miRNA) sponges, circular RNAs (circRNAs) have been discovered to be critical modulators of inflammatory processes. Ricin Toxin (RT) is highly toxic to mammalian cells and low doses of RT can induce acute inflammation. However, current researches on the underlying mechanism and function of circRNA/miRNA network in RT-induced inflammation are limited. Previously, we found miR-221-5p was aberrant and associated with the inflammation of RT induction. In this study, based on the circRNA high-throughput sequencing (circRNA-seq), we obtained a novel circRNA termed circNLRP3 and revealed that circNLRP3 can sponge miR-221-5p, release its target mRNA A20, and further suppress NF-κB signaling pathway to alleviated RT-induced TNF-α production. Our findings elucidated a possible mechanistic link between the circNLRP3/miR-221-5p/A20 axis and RT-induced inflammatory response, which may broaden our understanding of RT poisoning.

Expression analysis of hsa_circ_0020397, hsa_circ_0005986, hsa_circ_0003028, and hsa_circ_0006990 in renal cell carcinoma

Renal cell carcinoma (RCC) is a prevalent heterogeneous kidney cancer. So far, different genes have been reported for RCC development. However, its particular molecular mechanism remains unclear. Circular RNAs (circRNAs), a class of non-coding RNAs, are involved in numerous biological processes in different malignancies such as RCC. This study aims to assess the expression and underlying mechanism of four circRNAs (hsa_circ_0020397, hsa_circ_0005986, hsa_circ_0003028, hsa_circ_0006990) with possible new roles in RCC. In the experimental step, we investigated the expression of these four circRNAs in our RCC samples using quantitative real-time polymerase chain reaction. In the bioinformatics step, the differential expressed mRNAs (DEmRNAs), and miRNAs (DEmiRNAs) were obtained from the GEO datasets using the GEO2R tool. A protein-protein interaction network was constructed using the STRING database, and hub genes were identified by Cytoscape. Molecular pathways associated with hub genes were detected using KEGG pathway enrichment analysis. Then, we utilized the ToppGene database to detect the relationships between DEmiRNAs and hub genes. Furthermore, interactions between circRNAs and DEmiRNAs were predicted by the StarBase and circinteractome databases. Finally, a circRNA-DEmiRNA-hub gene triple network was constructed. Our results revealed that the expression of hsa_circ_0020397, hsa_circ_0005986, and hsa_circ_0006990 was downregulated in RCC tissues. Moreover, these circRNAs had a significantly lower expression in patients with a history of kidney disease. Furthermore, hsa_circ_0003028 and hsa_circ_0006990 showed higher expression in the tumor of participants with Lymphovascular/perineural invasion and oncocytoma type, respectively. Based on bioinformatic results, 15 circRNA-DEmiRNA-hub gene ceRNA regulatory axes were predicted, which included three hub genes, five miRNAs, and four selected circRNAs. In conclusion, the current work is the first to emphasize the expression of the hsa_circ_0020397, hsa_circ_0005986, hsa_circ_0003028, and hsa_circ_0006990 in RCC patients presents a novel perspective on the molecular processes underlying the pathogenic mechanisms of RCC.

CircRNA3616 knockdown attenuates inflammation and apoptosis in spinal cord injury by inhibiting TLR4/NF-κB activity via sponging miR-137

PURPOSE

The present work focused on exploring the role of circRNA3616 in neuronal inflammation and apoptosis in spinal cord injury (SCI).

METHODS

The SCI mouse model and circRNA3616 knockdown SCI mouse model were established. This work focused on assessing the mouse locomotor function using Basso Mouse Scale (BMS) and BMS subscore. Hematoxylin-eosin (HE) staining and Tunel staining were conducted, while myeloperoxidase (MPO) activity was also detected on spinal cord tissues. We also knocked down circRNA3616 expression in NSC-34 cells. Meanwhile, the SCI cell model was established by oxygen glucose deprivation (OGD) in NSC-34 cells. Moreover, we conducted dual-luciferase reporter gene assay. Flow cytometry (FCM) was conducted to detect SCI cell apoptosis, whereas cell counting kit-8 (CCK-8) assay was performed to analyze cell viability. This study also implemented enzyme-linked immunosorbent assay to detect inflammatory factors in spinal cord tissues, serum, and cells.

RESULTS

CircRNA3616 knockdown reduced the damage, inflammatory response, apoptosis, and MPO activity in SCI mouse serum and spinal cord tissues. CircRNA3616 knockdown increased BMS and BMS subscore of SCI mice. CircRNA3616 up-regulated TLR4 expression by sponging miR-137. CircRNA3616 knockdown inhibited the TLR4, p-IkBα, p-p65/p65 protein expression, while promoting IkBα protein expression within SCI mouse spinal cord. TLR4 reversed circRNA3616 knockdown-induced inhibition on NF-κB pathway activity in SCI cells. CircRNA3616 knockdown attenuated neuronal cell inflammation and apoptosis via TLR4/NF-κB pathway after SCI.

CONCLUSION

CircRNA3616 silencing attenuates inflammation and apoptosis in SCI by inhibiting TLR4/NF-κB activity via sponging miR-137. CircRNA3616 is the possible anti-SCI therapeutic target.

Circ_0101692 knockdown retards the development of clear cell renal cell carcinoma through miR-384/FN1 pathway

PURPOSE

Circular RNA_0101692 (circ_0101692) is overexpressed in clear cell renal cell carcinoma (ccRCC) by microarray analyses. However, its function and action mechanism in ccRCC tumorigenesis is still elusive.

METHODS

Western blotting and qRT-PCR were executed to assess the circ_0101692, miR-384 and FN1 expression in ccRCC cells and tissues. Target relationships among them were determined via dual luciferase reporter and/or RNA immunoprecipitation assays. Cell proliferation was evaluated by CCK-8 assay. Caspase-3 activity assay was utilized to analyze cell apoptosis. To find out whether ccRCC cells might migrate, a transwell assay was performed. To assess the effects of circ_0101692 on tumor development in vivo, a mouse xenograft model was used.

RESULTS

High expression of circ_0101692 and FN1, and decreased miR-384 were determined in ccRCC. Cell growth, migration and viability were decreased whereas cell apoptosis was stimulated when circ_0101692 was knockdown. miR-384 inhibitor transfection attenuated the inhibiting impacts of circ_0101692 silencing on ccRCC cell progression. FN1 deletion further inverted the cancer-promoting effect of miR-384 downregulation on cell viability and migration. In addition, circ_0101692 could sponge miR-384 to relieve the inhibition of miR-384 on FN1 in ccRCC.

CONCLUSIONS

Circ_0101692 targeted miR-384/FN1 axis to facilitate cell proliferation, migration and repress apoptosis, thereby accelerating the development of ccRCC. This points out that circ_0101692/miR-384/FN1 axis might be a prospective target implemented for the future treatment of ccRCC.

The Role of miRNAs, circRNAs and Their Interactions in Development and Progression of Hepatocellular Carcinoma: An Insilico Approach

Hepatocellular carcinoma (HCC) is a type of malignant tumor. miRNAs are noncoding RNAs and their differential expression patterns are observed in HCC-induced by alcoholism, HBV and HCV infections. By acting as a competing endogenous RNA (ceRNA), circRNA regulates the miRNA function, indirectly controlling the gene expression and leading to HCC progression. In the present study, data mining was performed to screen out all miRNAs and circRNA involved in alcohol, HBV or HCV-induced HCC with statistically significant (≤0.05%) expression levels reported in various studies. Further, the interaction of miRNAs and circRNA was also investigated to explore their role in HCC due to various causative agents. Together, these study data provide a deeper understanding of the circRNA-miRNA regulatory mechanisms in HCC. These screened circRNA, miRNA and their interactions can be used as prognostic biomarkers or therapeutic targets for the treatment of HCC.

circRNA DENND1B inhibits tumorigenicity of clear cell renal cell carcinoma via miR-122-5p/TIMP2 axis

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cancers. However, circ_DENND1B has not been studied yet. GSE100186 dataset was used for the level analysis of circ_DENND1B. The quantitative real-time PCR was used to verify the expression of circ_DENND1B, microRNA-122-5p (miR-122-5p) and tissue inhibitor of metalloproteinases-2 (TIMP2) in ccRCC tissues and cells. Cell proliferation, migration, invasion and apoptosis were detected by colony formation assay, thymidine analog 5-ethynyl-2'-deoxyuridine assay, 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide, transwell and flow cytometry. The binding of miR-122-5p to circ_DENND1B/TIMP2 was investigated by dual-luciferase reporter assay. Finally, the role of circ_DENND1B in ccRCC was detected by tumorigenesis experiment in mice. circ_DENND1B was downregulated in ccRCC and circ_DENND1B overexpression suppressed the malignant behaviors of ccRCC cells. circ_DENND1B acted as a sponge of miR-122-5p. miR-122-5p upregulation reversed the effects of circ_DENND1B on cell proliferation, migration, invasion and apoptosis. TIMP2 was a target of miR-122-5p. Overexpression of circ_DENND1B regulated TIMP2 level by inhibiting miR-122-5p expression in ccRCC cells. circ_DENND1B overexpression inhibited the tumor growth of ccRCC in vivo. circ_DENND1B inhibited ccRCC cell progression by promoting TIMP2 expression by sponging miR-122-5p, suggesting that circ_DENND1B might be an effective therapeutic target for ccRCC.

Potential Value of Visfatin, Omentin-1, Nesfatin-1 and Apelin in Renal Cell Carcinoma (RCC): A Systematic Review and Meta-Analysis

Renal cell carcinoma (RCC) is the most lethal genitourinary malignancy. Obesity is a risk factor for RCC development. The role of adipokines in the relationship between obesity and RCC requires confirmatory evidence in the form of a systematic review and meta-analysis, specifically for visfatin, omentin-1, nesfatin-1 and apelin. A search of databases up to July 2022 (PubMed, Web of Science and Scopus) for studies reporting the association of these selected adipokines with RCC was conducted. A total of 13 studies fulfilled the selection criteria. Only visfatin (p < 0.05) and nesfatin-1 (p < 0.05) had a significant association with RCC. Meanwhile, apelin and omentin-1 showed no association with RCC. The meta-analysis results of nesfatin-1 showed no association with early-stage (OR = 0.09, 95% CI = −0.12−0.29, p = 0.41), late-stage (OR = 0.36, 95% CI = 0.07−1.89, p = 0.23) and low-grade (OR = 1.75, 95% CI = 0.37−8.27, p = 0.48) RCC. However, nesfatin-1 showed an association with a high grade of the disease (OR = 0.29, 95% CI = 0.13−0.61, p = 0.001) and poorer overall survival (OS) (HR = 3.86, 95% CI = 2.18−6.85; p < 0.01). Apelin showed no association with the risk of RCC development (mean difference = 21.15, 95% CI = −23.69−65.99, p = 0.36) and OS (HR = 1.04, 95% Cl = 0.45−2.41; p = 0.92). Although the number of studies evaluated was limited, analysis from this systematic review and meta-analysis indicate that visfatin and nesfatin-1 were elevated. In summary, these adipokines may play a role in the development and progression of RCC and hence may have potential diagnostic and prognostic capabilities for RCC.

Bioinformatics analysis of immune-related prognostic genes and immunotherapy in renal clear cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is an immunogenic tumor, and investigating the immunorelated genes is essential. To investigate the immunoprognostic genes of ccRCC, we analyzed the data assimilated from a public database (The Cancer Genome Atlas (TCGA) database and the gene expression omnibus (GEO) database) using bioinformatics. Then, an immunoprognosis model was constructed to identify four hub genes with moderate predictive values for the prognosis of ccRCC patients. These four genes were associated with the prognosis of ccRCC patients based on Oncomine and Gena Expression Profiling Interactive Analysis (GEPIA) databases. The correlation analysis between the immune infiltrate, immune checkpoints, and immunotherapy and this immunoprognosis model showed that immune infiltration could predict the immunotherapy effects. We also conducted a quantitative real-time polymerase chain reaction analysis and found that the expressions of three hub genes were associated with tumor progression (P<0.1). In conclusion, four genes that may serve as potential biomarkers in ccRCC were identified with respect to prognosis.

Exosome-delivered circSATB2 targets the miR-330-5p/PEAK1 axis to regulate proliferation, migration and invasion of lung cancer cells

Exosomes can carry various kinds of RNAs to mediate intercellular communication. Circular RNA (circRNA) special AT-rich sequence-binding protein 2 (circSATB2) was identified as an oncogene in lung cancer. This study was performed to explore the association of circSATB2 with exosomes and the regulatory mechanism of circSATB2. Exosomes could transmit circSATB2 into lung cancer cells. Exosomes enhanced cell proliferation, invasion, and migration by carrying circSATB2. Exosomal circSATB2 abrogated the inhibitory effect of short hairpin (sh)-circSATB2 on lung cancer progression. Moreover, circSATB2 promoted tumor growth in vivo via exosomes. CircSATB2 interacted with microRNA-330-5p (miR-330-5p) and miR-330-5p targeted pseudopodium enriched atypical kinase 1 (PEAK1). In addition, circSATB2 affected the PEAK1 level via sponging miR-330-5p in lung cancer cells. All results suggested that exosomal transfer of circSATB2 contributed to the malignant development of lung cancer by acting as a sponge of miR-330-5p to upregulate PEAK1.

Circ_0039569 contributes to the paclitaxel resistance of endometrial cancer via targeting miR-1271-5p/PHF6 pathway

Circular RNA (circRNA) has been confirmed to be involved in the chemoresistance process of cancers. However, whether circ_0039569 mediates the chemoresistance of endometrial cancer (EC) remains unclear. Quantitative real-time PCR was performed to analyze circ_0039569, microRNA (miR)-1271-5p and PHD finger protein 6 (PHF6) expression. Cell counting kit-8 assay was used to assess the paclitaxel (PTX) resistance of cells. Cell proliferation, apoptosis and invasion were determined using EdU assay, colony formation assay, flow cytometry and transwell assay. Protein expression was examined by western blot analysis. RNA interaction was verified by dual-luciferase reporter assay and RNA pull-down assay. Xenograft tumor models were constructed to explore the effect of circ_0039569 knockdown on the PTX sensitivity of EC tumors. Circ_0039569 was upregulated in PTX-resistant EC tissues and cells. Knockdown of circ_0039569 enhanced the PTX sensitivity of EC cells by inhibiting cell growth and invasion. MiR-1271-5p could be sponged by circ_0039569, and its inhibitor abolished the regulation of circ_0039569 knockdown on the PTX sensitivity of EC cells. PHF6 was targeted by miR-1271-5p, and its overexpression eliminated the promotion effect of miR-1271-5p on the PTX sensitivity of EC cells. Also, interference of circ_0036569 enhanced the PTX sensitivity of EC tumors by regulating the miR-1271-5p/PHF6 pathway. Collectively, circ_0039569 might contribute to the PTX resistance of EC through the regulation of the miR-1271-5p/PHF6 axis.

A circular RNA derived from GLIS3 accelerates the proliferation of glioblastoma cells through competitively binding with miR-449c-5p to upregulate CAPG and GLIS3

Background

Glioblastoma (GBM) is an aggressive and malignant brain tumor with extremely poor prognosis. Despite advances in treatment, the pathogenesis of GBM remains elusive. Mounting studies have revealed the critical role of circular RNAs (circRNAs) in the development and progression of human cancers including GBM, but the comprehension of their functions is still insufficient. In this study, we investigated the expression profile of a circRNA derived from GLIS family zinc finger 3 (GLIS3) in GBM and normal astrocytes. CircGLIS3 expression was detected through quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Functional experiments were performed to analyze the influence of circGLIS3 on GBM cell proliferation and apoptosis. In addition, mechanism assays were to uncover the potential regulatory mechanism of circGLIS3.

Results

CircGLIS3 was up-regulated in GBM cells and knockdown of circGLIS3 significantly hampered proliferation and promoted apoptosis of GBM cells. Furthermore, circGLIS3 positively regulated CAPG and GLIS3 by sponging miR-449c-5p to affect GBM cell proliferation and apoptosis.

Conclusions

In summary, our study identified that circGLIS3 could promote proliferation and inhibit apoptosis of GBM cells via targeting miR-449c-5p/GLIS3/CAPG axis in vitro. This study could offer a novel molecular perspective for further investigation into mechanisms essential to GBM progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-022-00736-6.

Circular RNA hsa_circ_0002360 Promotes Proliferation and Invasion and Inhibits Oxidative Stress in Gastric Cancer by Sponging miR-629-3p and Regulating the PDLIM4 Expression

Many studies have found that circRNA hsa_0002360 (circ0002360) plays an important role in cancer onset and progression. However, its role in gastric cancer (GC) remains uncertain. Circ0002360 was found to be upregulated in GC cells using QRT-PCR. Furthermore, miR-629-3p, a target miRNA of circ0002360, was the most suppressed miRNA following circ0002360 overexpression. RNA immunoprecipitation (RIP), dual-luciferase reporter analyses, clone formation, transwell, DCFH-DA, and ELISA assays demonstrated that circ0002360-targeted miR-629-3p promotes cell proliferation and migration while inhibiting oxidative stress. GC-related mRNA microarrays from the GEO and TCGA databases, including GSE103236, GSE79973, GSE33429, GSE22804, GSE84437, and TCGA-STAD datasets, were used to find hub biomarkers between normal and gastric cancer samples. WGCNA and uni-Cox analysis were used to identify 27 survival-related risk genes, which were then used to build a risk model for prognosis prediction. Following that, all patients from the GSE84437 and TCGA-STAD datasets with 27 survival-related genes and enough data on survival status and time were randomly assigned to train (n = 433) and test (n = 375) cohorts. Furthermore, ROC and Kaplan-Meier (KM) analyses were used to validate the risk model for both cohorts. randomForest analysis indicated that PDLIM4 was the target gene of miR-629-3p, whose level was increased by circ0002360 but reversed by miR-629-3p mimics. Finally, this study confirmed that circ0002360 sponged miR-629-3p and then upregulated PDLIM4 expression. As a result, circ0002360 may be a useful marker for predicting GC prognosis and an anti-GC treatment target.

The clinical significance, immune infiltration, and tumor mutational burden of angiogenesis-associated lncRNAs in kidney renal clear cell carcinoma

Background

Poor prognosis of kidney renal clear cell carcinoma (KIRC) is often related to angiogenesis. The lncRNAs that regulate angiogenesis could also affect the prognosis of KIRC. It is meaningful for us to use lncRNAs related to angiogenesis to construct a generic, individualized prognostic signature for patients with KIRC.

Methods

We identified eight angiogenesis-associated genes (AAGs) by differential expression analysis and univariate Cox regression from The Cancer Genome Atlas dataset, including 537 KIRC samples and 72 normal samples. In total, 23 prognostic lncRNAs were screened out after Pearson correlation analysis and univariate Cox regression analysis. Then, we performed least absolute shrinkage and selection operator (LASSO) regression and multivariate Cox regression to establish a four-AAG-related lncRNA prognostic signature.

Results

The risk score was calculated for each KIRC patients by using a four-AAG-related lncRNA prognostic signature. We divided the KIRC patients into high- and low-risk groups by the median of the risk score. It was confirmed that the AAG-related lncRNA prognostic signature has good prognostic value for KIRC patients by time-dependent receiver operating characteristic and Kaplan–Meier survival analysis. We identified 3,399 differentially expressed genes between the high- and low-risk groups and performed their functional enrichment analyses. The AAG-related lncRNA prognostic signature was an independent prognostic predictor for KIRC patients and was used to perform a combined nomogram. We reevaluated them in terms of survival, clinic characteristics, tumor-infiltrating immune cells and tumor mutation burden.

Conclusion

Our research indicates that the AAG-related lncRNA prognostic signature is a promising and potential independent prognostic indicator for KIRC patients. Then, it could offer new insights into the prognosis assessment and potential treatment strategies of KIRC patients.

Construction of a circular RNA-based competing endogenous RNA network to screen biomarkers related to intervertebral disc degeneration

Background

Intervertebral disc degeneration (IDD) is a leading cause of disability with limited treatment strategies. A better understanding of the mechanism of IDD might enable less invasive and more targeted treatments. This study aimed to identify the circular RNA (circRNA)–microRNA (miRNA)–messenger RNA (mRNA) competing endogenous RNA (ceRNA) regulatory mechanisms in IDD.

Methods 

The GSE67567 microarray dataset was downloaded from the Gene Expression Omnibus database. After data preprocessing, differentially expressed circRNAs, miRNAs and mRNAs between IDD and controls were identified. A ceRNA network was constructed on the basis of the interaction between circRNAs and miRNAs, and miRNAs and mRNAs. Pathway enrichment analysis was performed on the mRNAs in the ceRNA network. Then, with ‘intervertebral disc degeneration’ as keywords, IDD-related Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were searched for in the Comparative Toxicogenomics Database.

Results

A total of 105 differentially expressed circRNAs, 84 miRNAs and 967 mRNAs were identified. After analysis, 86 circRNA–miRNA, and 126 miRNA–mRNA regulatory relationship pairs were obtained to construct a ceRNA network. The mRNAs were enriched in six KEGG signalling pathways, and four were associated with IDD: the hsa04350: TGF-beta signalling pathway, hsa04068: FoxO signalling pathway, hsa05142: Chagas disease (American trypanosomiasis) and hsa04380: Osteoclast differentiation. An IDD-related ceRNA network was constructed involving four circRNAs, three miRNAs and 11 mRNAs. Auxiliary validation showed that the expression levels of miR-185-5p, miR-486-5p, ACVR1B, FOXO1, SMAD2 and TGFB1 were consistent in different databases.

Conclusions

Our study identified some circRNA–miRNA–mRNA interaction axes potentially associated with the progression of IDD, viz.: circRNA_100086–miR-509-3p–MAPK1, circRNA_000200–miR-185-5p–TGFB1, circRNA_104308–miR-185-5p–TGFB1, circRNA_400090–miR-486-5p–FOXO1 and circRNA_400090–miR-486-5p–SMAD2.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05579-0.

1. An IDD-related ceRNA network involving four circRNAs, three miRNAs and 11 mRNAs was constructed.

2. The expression levels of miR-185-5p, miR-486-5p, FOXO1, SMAD2 and TGFB1 were consistent in different databases.

3. Our study identified IDD-related circRNA–miRNA–mRNA interaction axes, including circRNA_100086–miR-509-3p–MAPK1.

Use of Circular RNAs in Diagnosis, Prognosis and Therapeutics of Renal Cell Carcinoma

Renal cell carcinoma is the most common type of kidney cancer, representing 90% of kidney cancer diagnoses, and the deadliest urological cancer. While the incidence and mortality rates by renal cell carcinoma are higher in men compared to women, in both sexes the clinical characteristics are the same, and usually unspecific, thereby hindering and delaying the diagnostic process and increasing the metastatic potential. Regarding treatment, surgical resection remains the main therapeutic strategy. However, even after radical nephrectomy, metastasis may still occur in some patients, with most metastatic renal cell carcinomas being resistant to chemotherapy and radiotherapy. Therefore, the identification of new biomarkers to help clinicians in the early detection, and treatment of renal cell carcinoma is essential. In this review, we describe circRNAs related to renal cell carcinoma processes reported to date and propose the use of some in therapeutic strategies for renal cell carcinoma treatment.

Circ_0037866 Contributes to the Tumorigenesis of Renal Cell Carcinoma by Sequestering miR-384 to Elevate Chromobox 5 Expression

BACKGROUND

Circular RNAs (circRNAs) were demonstrated to have roles in the carcinogenesis of renal cell carcinoma (RCC). Hence, this work aimed to determine the functions and molecular mechanism of circ_0037866 in regulating the progression of RCC.

METHODS

Quantitative real-time polymerase chain reaction and Western blotting were used to detect the levels of genes and proteins. In vitro assays, including colony formation, 5-ethynyl-2'-deoxyuridine, flow cytometry, transwell assays, and in vivo tumor formation, were conducted to investigate the effects of circ_0037866 on RCC tumorigenesis. Dual-luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation assay were used to confirm the interaction between miR-384 and circ_0037866 or Chromobox 5 (CBX5).

RESULTS

Circ_0037866 is a stable circRNA and was found to be increased in RCC tissues and cells. Functionally, circ_0037866 silencing suppressed RCC cell survival, invasion, and migration in vitro, and impeded RCC cell tumorigenesis in the subcutaneous xenograft model. Mechanistically, circ_0037866 could function as a sponge for miR-384 to elevate the expression of its target CBX5. Furthermore, a series of rescue experiments showed that miR-384 inhibition reversed the anticancer effects of circ_0037866 knockdown on RCC cells; besides that, miR-384 restoration suppressed RCC cell growth and mobility, which were attenuated by CBX5 overexpression.

CONCLUSION

Circ_0037866 knockdown restrains the tumorigenesis of RCC by miR-384/CBX5, revealing a promising molecular target for RCC therapy.

A ceRNA Network Composed of Survival-Related lncRNAs, miRNAs, and mRNAs in Clear Cell Renal Carcinoma

Clear cell renal carcinoma (ccRCC) is one of the most common renal carcinomas worldwide, which has worse prognosis compared with other subtypes of tumors. We propose a potential RNA regulatory mechanism associated with ccRCC progression. Accordingly, we screened out clinical factors and the expression of RNAs and miRNAs of ccRCC from the TCGA database. 9 lncRNAs (FGF12-AS2, WT1-AS, TRIM36-IT1, AC009093.1, LINC00443, TCL6, COL18A1-AS1, AC110619.1, HOTTIP), 2 miRNAs (mir-155 and mir-21), and 3 mRNAs (COL4A4, ERMP1, PRELID2) were selected from differential expression RNAs and built predictive survival models. The survival models performed very well in predicting prognosis and were found to be highly correlated with tumor stage. In addition, the survival-related lncRNA-miRNA-mRNA (ceRNA) network was constructed by 18 RNAs including 12 mRNAs, 2 miRNAs, and 4 lncRNAs. It is found that the “ECM-receptor interaction,” “Pathways in cancer,” and “Chemokine signaling pathway” as the main pathways in KEGG pathway analysis. Overall, we established predictive survival model and ceRNA network based on multivariate Cox regression analysis. It may open a new approach and potential biomarkers for clinical prognosis and treatment of ccRCC patients.

Circular RNAs as emerging players in cervical cancer tumorigenesis; A review to roles and biomarker potentials

Cervical cancer is the most lethal gynecological cancer among women worldwide. Most of the patients are diagnosed at the advanced stages due to late diagnosis and lack of accessible and valuable approaches for early detection of the disease. Circular RNAs (circRNAs) are a distinguishable class of non-coding RNAs with characteristic loop structures. Although their function has not been completely elucidated; however, recent evidence has suggested regulatory functions for circRNAs on gene expression controlling various biological functions like cell growth and apoptosis, development, embryogenesis, and pathogenesis of human diseases particularly cancers. Studies show the role of dysregulated circRNAs in biological processes including cell proliferation, migration, invasion, apoptosis, angiogenesis, and chemoresistance contributing to affect tumorigenesis in ovarian cancer cells, animal, and clinical studies. These effects can be defined as consistent with several tumorigenesis characteristics, which are defined as "hallmarks of cancer". Additionally, dysregulated circRNAs exhibit prognostic, and diagnostic potentials both in the prediction of prognosis in ovarian cancer patients, and also their discrimination from healthy individuals. Furthermore, targeting circRNAs has shown positive results in the suppression of malignant features of cancer cells, and also in overcoming chemoresistance. In this review, I have gathered the majority of studies evaluating the role of circRNAs in the development, and progression of cervical cancer, and also have discussed prognostic, diagnostic, and therapeutic potentials of circRNAs for clinical applications in cervical cancer patients.

Circ_RPPH1 regulates glioma cell malignancy by binding to miR-627-5p/miR-663a to induce SDC1 expression

BACKGROUND

Recent studies revealed the key role of circular RNA (circRNA) in glioma progression. However, the effect of circ_0000520, also named as circRNA ribonuclease P RNA component H1 (circ_RPPH1), in glioma development was unknown. The study aimed to reveal the role of circ_RPPH1 in glioma cell malignancy.

METHODS

Human astrocytes (NHA) and glioma cell lines (A172 and U251) were employed in this study. Quantitative real-time polymerase chain reaction and western blot were used to check the expression of circ_RPPH1, microRNA-627-5p (miR-627-5p), miR-663a and syndecan 1 (SDC1). Immunohistochemistry assay was conducted to assess the protein expression of nuclear proliferation marker ki67 and matrix metalloprotein 9 (MMP9). Cell viability was assessed by 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell proliferation and apoptosis were investigated by flow cytometry analysis, 5-Ethynyl-29-deoxyuridine, or cell colony formation assay. Cell migration and invasion were evaluated by transwell assays. The interaction between miRNAs (miR-627-5p and miR-663a) and circ_RPPH1 or SDC1 was identified by a dual-luciferase reporter assay. A mouse model assay was performed to reveal the impact of circ_RPPH1 knockdown on glioma cell malignancy in vivo by analyzing neoplasm volume and weight.

RESULTS

Circ_RPPH1 and SDC1 expression were significantly increased, whereas miR-627-5p and miR-663a expression were decreased in glioma tissues and cells in comparison with healthy brain tissues or human astrocytes. Circ_RPPH1 depletion led to the decreased cell proliferation, migration and invasion, and the increased cell apoptosis. Additionally, circ_RPPH1 bound to miR-627-5p/miR-663a and mediated glioma cell processes by interacting with them. SDC1 overexpression attenuated miR-627-5p/miR-663a-mediated actions. Moreover, circ_RPPH1 regulated SDC1 expression through interaction with miR-627-5p and/or miR-663a. Furthermore, circ_RPPH1 knockdown inhibited glioma cell malignancy in vivo, accompanied by the decreases of ki67 and MMP9 expression.

CONCLUSION

Circ_RPPH1 knockdown inhibited glioma tumorigenesis by downregulating SDC1 by binding to miR-627-5p/miR-663a, showing that circ_RPPH1 might be an effective therapeutic target for glioma.

Evaluation of Diagnostic and Prognostic Value of hsa_circ_0084927 and Analysis of Associated ceRNA Network in Colorectal Cancer

Object

This study aims to analyze the differentially expressed circRNA in colon adenocarcinoma (COAD) and evaluate its diagnostic and prognostic value. Analyze associated circRNA-miRNA-mRNA network in COAD.

Methods and Materials

Real-time quantitative PCR (RT-PCR) was used to verify differentially expressed circRNA in COAD tissues and cells; Receiver operator characteristic (ROC) and Cox regression analysis were used to evaluating its diagnostic and prognostic value; Meanwhile we conducted CCK-8, invasion, and migration experiments in cell lines to explore the function of circRNA. In addition, a competitive endogenous RNA (ceRNA) network was established using bioinformatics methods to explore its prognostic value and potential functional mechanisms.

Results

Our study found that hsa_circ_0084927 is highly expressed in COAD tissues and cell lines. Plasma hsa_circ_0084927 can be used as a diagnostic marker for COAD patients; hsa_circ_0084927 can promote the proliferation, migration and invasion of COAD cells. In addition, we effectively constructed a ceRNA: network has_circ_0084927/miR-106b-5p/VEGFA. The ceRNA network indicates that hsa_circ_0084927 may affect the prognosis of COAD through the regulation of cell cycle, apoptosis and other pathways.

Conclusion

Our research results indicate that hsa_circ_0084927 has a cancer-promoting effect and may be used as a circulating tumor marker for COAD prognosis. In addition, this study proposes a new ceRNA network to provide new insights for the targeted therapy of COAD.

An Integrative Analysis Framework for Identifying the Prognostic Markers from Multidimensional RNA Data of Clear Cell Renal Cell Carcinoma

The altered regulatory status of long noncoding RNA (lncRNA), miRNA, and mRNA and their interactions play critical roles in tumor proliferation, metastasis, and progression, which ultimately influence cancer prognosis. However, there are limited studies of comprehensive identification of prognostic biomarkers from combined data sets of the three RNA types in the highly metastatic clear cell renal cell carcinoma (ccRCC). The current study employed an integrative analysis framework of functional genomics approaches and machine learning methods to the lncRNA, miRNA, and mRNA data and identified 16 RNAs (3 lncRNAs, 6 miRNAs, and 7 mRNAs) of prognostic value, with 9 of them novel. A 16 RNA-based score was established for prognosis prediction of ccRCC with significance (P < 0.0001). The area under the curve for the score model was 0.868 to 0.870 in the training cohort and 0.714 to 0.778 in the validation cohort. Construction of the lncRNA-miRNA-mRNA interaction network showed that the downstream mRNAs and upstream lncRNAs in the network initiated from the miRNA or lncRNA markers exhibit significant enrichment in functional classifications associated with cancer metastasis, proliferation, progression, or prognosis. The functional analysis provided clear support for the role of the RNA biomarkers in predicting cancer prognosis. This study provides promising biomarkers for predicting prognosis of ccRCC using multidimensional RNA data, and these findings are expected to facilitate potential clinical applications of the biomarkers.

hsa_circ_0119412 overexpression promotes cervical cancer progression by targeting miR-217 to upregulate anterior gradient 2

BACKGROUND

Mounting evidence summarizes that circRNA is closely implicated in the development of numerous cancers. Our study aimed to investigate the role of circ_0119412 whose function was not explored in cervical cancer.

METHODS

RT-qPCR analysis was utilized for the expression analysis of circ_0119412, miR-217, and anterior gradient 2 (AGR2). CCK-8 assay, transwell assay, and MTT assay were employed to assess cell proliferation, migration, and adhesion, respectively. Animal study was performed to check the role of circ_0119412 in vivo. Bioinformatics analysis was applied to predict the downstream targets of circ_0119412. RIP assay was utilized to examine miRNAs potentially bound by circ_0119412. The interplays between miR-217 and circ_0119412 or AGR2 were validated by dual-luciferase reporter assay.

RESULTS

circ_0119412 expression was highly enhanced in cervical tumor tissues and cancer cells. circ_0119412 overexpression aggravated cervical cancer cell proliferation, migration, and adhesion, and its overexpression was also conducive to tumor formation and growth in animal models. AGR2 was upregulated in cervical cancer by the public bioinformatics data. circ_0119412 bound to miR-217, and miR-217 bound to AGR 3'UTR. The promoting effects of circ_0119412 overexpression on cancer cell malignant phenotypes were reversed by miR-217 enrichment. In addition, increased expression of miR-217 suppressed AGR2 expression, thus weakening the functional effects of AGR2.

CONCLUSION

circ_0119412 functioned as an oncogenic driver to promote the malignant development of cervical cancer by targeting the miR-217/AGR2 pathway.

Identification of potential circular RNA biomarkers in lung adenocarcinoma: A bioinformatics analysis and retrospective clinical study

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-associated mortality. Lung adenocarcinoma (LAC) is the most prevalent pathological subtype of NSCLC and accounts for ~40% of all lung cancer mortalities. There remains an urgent demand for the identification of novel biomarkers for the diagnosis and development of therapeutic strategies for LAC. In the present study, the profiles of the differentially-expressed circular RNAs (circRNAs) in LAC tissues compared with those in their corresponding non-cancerous tissues were obtained after analyzing the circRNA microarray dataset GSE101586. The expression pattern of the indicated circRNAs in the LAC tissues were subsequently verified using reverse transcription-quantitative PCR (RT-qPCR). The potential prognostic significance of these circRNAs in patients with LAC were then analyzed in a retrospective clinical study. A circRNA-microRNA (miR or miRNA)-mRNA regulatory network in LAC was established by using Cytoscape. In addition, a protein-protein interaction (PPI) network was plotted using the Search Tool for the Retrieval of Interacting Genes/Proteins and visualized through Cytoscape. The prognostic value of the hub genes found was then analyzed based on the Gene Expression Profiling Interactive Analysis database. In total, four differentially-expressed circRNAs were obtained from the GSE101586 microarray dataset, three of which (hsa_circ_0006220, hsa_circ_0072088 and hsa_circ_0001666) were confirmed by RT-qPCR to be highly expressed in LAC tissues. This retrospective clinical study revealed that higher expression levels of these three circRNAs were associated with poorer prognoses in patients with LAC. In addition, siRNA-mediated knockdown of these circRNAs was found to inhibit cell proliferation, migration and invasion in LAC cells. Following analysis of the molecular mechanism underlying these circRNAs, eight miRNAs, namely miR-520f, miR-1261, miR-1270, miR-620, miR-188-3p, miR-516b, miR-940 and miR-661, were identified with potential binding sites for these three circRNAs. Subsequently, 232 overlapped genes from the 795 upregulated genes in the LAC samples from The Cancer Genome Atlas database and 7,829 predicted target genes of the list of eight aforementioned miRNAs were obtained. A circRNA-miRNA-mRNA network was then constructed. A PPI network was established, with six hub genes, namely kinesin family member (KIF) 2C, KIF18B, maternal embryonic leucine zipper kinase, baculoviral IAP repeat-containing 5, polo-like kinase 1 and cytoskeleton-associated protein 2-like, determined from this network. Higher expression levels of each of these hub genes were found to be associated with poorer prognoses of patients with LAC. To conclude, data from the present study suggested that circRNAs hsa_circ_0006220, hsa_circ_0072088 and hsa_circ_0001666 have the potential to be viable biomarkers and therapeutic targets for LAC.

Identification of Hypoxia-Immune-Related Gene Signatures and Construction of a Prognostic Model in Kidney Renal Clear Cell Carcinoma

Introduction: Kidney renal clear cell carcinoma (KIRC), a kind of malignant disease, is a severe threat to public health. Tracking the information of tumor progression and conducting a related dynamic prognosis model are necessary for KIRC. It is crucial to identify hypoxia-immune-related genes and construct a prognostic model due to immune interaction and the influence of hypoxia in the prognosis of patients with KIRC. Methods: The hypoxia and immune status of KIRC patients were identified by utilizing t-SNE and ImmuCellAI for gene expression data. COX and Lasso regression were used to identify some hypoxia-immune-related signature genes and further construct a prognostic risk model based on these genes. Internal and external validations were also conducted to construct a prognostic model. Finally, some potentially effective drugs were screened by the CMap dataset. Results: We found that high-hypoxia and low-immune status tend to induce poor overall survival (OS). Six genes, including PLAUR, UCN, PABPC1L, SLC16A12, NFE2L3, and KCNAB1, were identified and involved in our hypoxia-immune-related prognostic risk model. Internal verification showed that the area under the curve (AUC) for the constructed models for 1-, 3-, 4-, and 5-year OS were 0.768, 0.754, 0.775, and 0.792, respectively. For the external verification, the AUC for 1-, 3-, 4-, and 5-year OS were 0.768, 0.739, 0.763, and 0.643 respectively. Furthermore, the decision curve analysis findings demonstrated excellent clinical effectiveness. Finally, we found that four drugs (including vorinostat, fludroxycortide, oxolinic acid, and flutamide) might be effective and efficient in alleviating or reversing the status of severe hypoxia and poor infiltration of immune cells. Conclusion: Our constructed prognostic model, based on hypoxia-immune-related genes, has excellent effectiveness and clinical application value. Moreover, some small-molecule drugs are screened to alleviate severe hypoxia and poor infiltration of immune cells.

Circ_0025033 deficiency suppresses paclitaxel resistance and malignant development of paclitaxel-resistant ovarian cancer cells by modulating the miR-532-3p/FOXM1 network

BACKGROUND

Ovarian cancer (OC) is the main cause of cancer-related death in women, and drug resistance is a leading cause of treatment failure. Recently, the involvement of circular RNAs (circRNAs) in cancer progression has become an area of increased investigation. The objective of this study is to uncover the function and regulatory mechanism of circ_0025033 in paclitaxel (PTX)-resistant OC cells.

METHODS

The expression of circ_0025033, FOXM1 and miR-532-3p was investigated using quantitative real-time polymerase chain reaction (qRT-PCR), and the protein expression of FOXM1 was quantified by western blot. Cell biological functions, including cell viability, migration/invasion and apoptosis, were explored using 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays, transwell assays and flow cytometry assays. The interaction between miR-532-3p and circ_0025033 or FOXM1 predicted by bioinformatics analysis was validated by pull-down assay and dual-luciferase reporter assay. Exosomes were isolated to determine the further function of circ_0025033.

RESULT

Circ_0025033 and FOXM1 were highly expressed, while miR-532-3p was poorly expressed in OC tissues and cells, and the expression pattern was greater in PTX-resistant OC cells. Circ_0025033 knockdown lessened PTX resistance, suppressed migration/invasion and promoted apoptosis of PTX-resistant cells. With respect to mechanism, circ_0025033 upregulated the expression of FOXM1 by targeting miR-532-3p, and circ_0025033 knockdown blocked the malignant activities of PTX-resistant OC cells by enriching miR-532-3p and suppressing FOXM1. Exosomes derived from PTX-resistant cells with circ_0025033 knockdown also could repress the malignant actions of PTX-resistant OC cells.

CONCLUSION

Circ_0025033 downregulation impaired PTX resistance and malignant activities of PTX-resistant OC cells by regulating the miR-532-3p/FOXM1 network.

New Tricks with Old Dogs: Computational Identification and Experimental Validation of New miRNA–mRNA Regulation in hiPSC-CMs

Cardiovascular disease is still the leading cause of morbidity and mortality worldwide. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have become a valuable widespread in vitro model to study cardiac disease. Herein, we employ the hiPSC-CM model to identify novel miRNA–mRNA interaction partners during cardiac differentiation and β-adrenergic stress. Whole transcriptome and small RNA sequencing data were combined to identify novel miRNA–mRNA interactions. Briefly, mRNA and miRNA expression profiles were integrated with miRNA target predictions to identify significant statistical dependencies between a miRNA and its candidate target set. We show by experimental validation that our approach discriminates true from false miRNA target predictions. Thereby, we identified several differentially expressed miRNAs and focused on the two top candidates: miR-99a-5p in the context of cardiac differentiation and miR-212-3p in the context of β-adrenergic stress. We validated some target mRNA candidates by 3′UTR luciferase assays as well as in transfection experiments in the hiPSC-CM model system. Our data show that iPSC-derived cardiomyocytes and computational modeling can be used to uncover new valid miRNA–mRNA interactions beyond current knowledge.

Exosomal circ_PTPRA inhibits tumorigenesis and promotes radiosensitivity in colorectal cancer by enriching the level of SMAD4 via competitively binding to miR-671-5p

Accumulating evidence supports that exosomal RNAs are crucial in tumor microenvironment and may be used as diagnostic biomarkers for cancers. This study aimed to determine the role of exosomal circular RNA_protein tyrosine phosphatase receptor type A (circ_PTPRA) in colorectal cancer (CRC). The morphology of exosomes was identified by transmission electron microscopy (TEM), and several exosome-specific proteins were quantified by western blot. The expression of circ_PTPRA, miR-671-5p and SMAD family member 4 (SMAD4) was detected using quantitative polymerase chain reaction (qPCR). Cell cycle was assessed using flow cytometry assay. Cell proliferation was assessed by MTT assay. Radiosensitivity was observed according to colony growth and cell apoptosis rate by colony formation assay and flow cytometry assay. The protein levels of proliferation- and apoptosis-related markers and SMAD4 were measured by western blot. The predicted relationship between miR-671-5p and circ_PTPRA or SMAD4 was verified by dual-luciferase reporter assay. Animal study was performed to investigate the role of exosomal circ_PTPRA in vivo. Circ_PTPRA expression was declined in serumal exosomes from CRC patients and CRC cell lines. Exosomal circ_PTPRA induced CRC cell cycle arrest and inhibited cell proliferation. Besides, exosomal circ_PTPRA promoted radiosensitivity of CRC cells, leading to inhibitory colony formation and increased apoptotic rate. In mechanism, circ_PTPRA functioned as a competing endogenous RNA (ceRNA) to increasing SMAD4 level by binding to miR-671-5p. Rescue experiments concluded that circ_PTPRA inhibited CRC growth and radioresistance by decreasing miR-671-5p expression, and miR-671-5p inhibition also inhibited CRC growth and radioresistance by enriching SMAD4 expression. Moreover, exosomal circ_PTPRA blocked tumor growth in vivo. Exosomal circ_PTPRA enhanced CRC cell radiosensitivity and inhibited CRC malignant development partially by regulating the miR-671-5p/SMAD4 pathway, hinting that exosomal circ_PTPRA might be used as a potential predicted and therapeutic target for CRC.

Circular RNA-associated ceRNA network involved in HIF-1 signalling in triple-negative breast cancer: circ_0047303 as a potential key regulator

The aggressive and highly metastatic nature of triple‐negative breast cancer (TNBC) causes patients to suffer from the poor outcome. HIF‐1 signalling pathway is a prominent pathway that contributes to angiogenesis and metastasis progression in tumours. On the contrary, the undeniable importance of circular RNAs (circRNAs) as multifunctional non‐coding RNAs (ncRNAs) has been identified in breast cancer. These ncRNAs owing to their high stability and specificity have been becoming a hotspot in cancer researches. circRNAs act as competing endogenous RNAs (ceRNAs) and compete with mRNAs for shared miRNAs, thus modulate gene expression. Since the most dysregulated biological functions in TNBC are associated with cellular invasion, understanding the molecular pathogenesis of these processes is a crucial step towards the development of new treatment approaches. The purpose of this study is to undermine the circRNA‐associated ceRNA network involved in HIF‐1 signalling in TNBC using an integrative bioinformatics approach. In the next step, the novel circ_0047303‐mediated ceRNA regulatory axes have been extracted and validated across TNBC samples. We show that circ_0047303 has the highest degree in the circRNA‐associated ceRNA network and shows a significant up‐expression in TNBC. Moreover, our results suggest that circ_0047303 could mediate the upregulation of key angiogenesis‐related genes, including HIF‐1, EIF4E2 and VEGFA in TNBC through sponging the tumour‐suppressive miRNAs. The circ_0047303 could be a promising molecular biomarker and/or therapeutic target for TNBC.

Construction of circRNA-based ceRNA network and its prognosis-associated subnet of clear cell renal cell carcinoma

Circular RNAs (circRNAs) are novel biomarkers of various cancers. CircRNAs can sponge miRNAs and regulate target mRNAs, which was called competing endogenous RNAs (ceRNA). This study was designed to identify circRNAs related to patients with clear cell renal cell carcinoma (ccRCC) and the first to select three independent Gene Expression Omnibus microarrays covering circRNAs, miRNAs, and mRNAs for multiple analyses. The data of clinical cases applied in our study were obtained from The Cancer Genome Atlas. We successfully conducted a circRNA/miRNA/mRNA ceRNA network related to ccRCC patients via R software and Cytoscape including 8 circRNAs, 6 miRNAs, and 49 mRNAs. The prognosis‐associated subnet covered 8 circRNAs, 6 miRNAs, and 22 mRNAs. Quantitative real‐time PCR was applied to measure our prediction in three renal cell lines and 23 pairs of tissues. Small interfering RNA targeting the back‐splice region of hsa_circ_0001167 was further implied to confirm the regulation. Ultimately, hsa_circ_0001167/hsa‐miR‐595/CCDC8 regulatory axis was identified in this study, which may serve as prognostic indicators. Lower levels of hsa_circ_0001167 and CCDC8 were potentially correlated with worse patient survival.

Differentially expressed miRNAs in bone after methotrexate treatment

Previous studies have shown that administration of antimetabolite methotrexate (MTX) caused a reduced trabecular bone volume and increased marrow adiposity (bone/fat switch), for which the underlying molecular mechanisms and recovery potential are unclear. Altered expression of microRNAs (miRNAs) has been shown to be associated with dysregulation of osteogenic and/or adipogenic differentiation by disrupting target gene expression. First, the current study confirmed the bone/fat switch following MTX treatment in precursor cell culture models in vitro. Then, using a rat intensive 5-once daily MTX treatment model, this study aimed to identify miRNAs associated with bone damage and recovery (in a time course over Days 3, 6, 9, and 14 after the first MTX treatment). RNA isolated from bone samples of treated and control rats were subjected to miRNA array and reverse transcription-polymerase chain reaction validation, which identified five upregulated miRNA candidates, namely, miR-155-5p, miR-154-5p, miR-344g, miR-6215, and miR-6315. Target genes of these miRNAs were predicted using TargetScan and miRDB. Then, the protein-protein network was established via STRING database, after which the miRNA-key messenger RNA (mRNA) network was constructed by Cytoscape. Functional annotation and pathway enrichment analyses for miR-6315 were performed by DAVID database. We found that TGF-β signaling was the most significantly enriched pathway and subsequent dual-luciferase assays suggested that Smad2 was the direct target of miR-6315. Our current study showed that miR-6315 might be a vital regulator involved in bone and marrow fat formation. Also, this study constructed a comprehensive miRNA-mRNA regulatory network, which may contribute to the pathogenesis/prognosis of MTX-associated bone loss and bone marrow adiposity.

Identification of Potential Genomic Alterations and the circRNA-miRNA-mRNA Regulatory Network in Primary and Recurrent Synovial Sarcomas

Introduction: Synovial sarcoma (SS) is one of the most invasive soft tissue sarcomas, prone to recurrence and metastasis, and the efficacy of surgical treatment and chemotherapy for SS remains poor. Therefore, the diagnosis and treatment of SS remain a significant challenge. This study aimed to analyze the mutated genes of primary SS (PSS) and recurrent SS (RSS), discover whether these sarcomas exhibit some potential mutated genes, and then predict associated microRNAs (miRNA) and circular RNAs (circRNA) by analyzing the mutated genes. We focused on the regulation mechanism of the circRNA-miRNA-mutated hub gene in PSS and RSS.

Methods: We performed a comprehensive genomic analysis of four pairs of formalin-fixed paraffin-embedded samples of PSS and RSS, using Illumina human exon microarrays. The gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) function, and pathway enrichment of the mutated genes were analyzed, and the protein-protein interaction (PPI) network was forecast using String software 11.0. The hub genes were then obtained using the Molecular Complex Detection (MCODE) plug-in for Cytoscape 3.7.2 and were used to analyze overall survival (OS) using the Gene Expression Profiling Interactive Analysis (GEPIA) database. The corresponding miRNAs were obtained from the miRDB 5.0 and TargetScan 7.2 databases. The corresponding circRNAs of the hub genes were found through the miRNAs from these databases: Circbank, CircInteractome, and StarBase v2.0. Thereafter we set up a competing endogenous RNA (ceRNA) network with circRNA-miRNA and miRNA-messenger RNA (mRNA) pairs.

Results: Using the chi-squared test, 391 mutated genes were screened using a significance level of p-values < 0.01 from the four pairs of PSS and RSS samples. A GO pathway analysis of 391 mutated genes demonstrated that differential expression mRNAs (DEmRNAs) might be bound up with the “positive regulation of neurogenesis,” “cell growth,” “axon part,” “cell−substrate junction,” or “protein phosphatase binding” of SS. The PPI network was constructed using 391 mutated genes, and 53 hub genes were identified (p < 0.05). Eight variant hub genes were discovered to be statistically significant using the OS analysis (p < 0.05). The circRNA-miRNA-mRNA (ceRNA) network was constructed, and it identified two circRNAs (hsa_circ_0070557 and hsa_circ_0070558), 10 miRNAs (hsa-let-7a-3p, hsa-let-7b-3p, hsa-let-7f-1-3p, hsa-let-7f-2-3p, hsa-mir-1244, hsa-mir-1197, hsa-mir-124-3p, hsa-mir-1249-5p, hsa-mir-1253, and hsa-mir-1271-5p) and five hub genes (CENPE, ENPP3, GPR18, MDC1, and PLOD2).

Conclusion: This study screened novel biological markers and investigated the differentiated circRNA-miRNA-mutated hub gene axis, which may play a pivotal role in the nosogenesis of PSS and RSS. Some circRNAs may be deemed new diagnostic or therapeutic targets that could be conducive to the future clinical treatment of SS.

CircRNA_0026344 via exosomal miR-21 regulation of Smad7 is involved in aberrant cross-talk of epithelium-fibroblasts during cigarette smoke-induced pulmonary fibrosis

For smoking-induced pulmonary fibrosis (PF), a serious disease endangering human health, there is no effective clinical treatment. Aberrant epithelium-fibroblast cross-talk is involved in formation of the excessive extracellular matrix (ECM) that contributes to PF. Circular RNAs have been associated with various pulmonary diseases. However, the mechanisms of circRNAs in PF are not clear. Herein, our goals were to investigate the involvement of circRNA_0026344 in the aberrant epithelium-fibroblast cross-talk induced by cigarette smoke (CS) and to define its mechanism. Chronic exposure (16 weeks) of BALB/c mice to 500 mg/m3 CS induced lung injury and fibrosis in lung tissues. From HBE cells, circRNA_0026344 was selected by microarray analysis and verified as that with the most severe down-regulation caused by cigarette smoke extract (CSE). The regulatory relationship between circRNA_0026344 and miR-21 was assessed by use of bioinformatics, RNA pull-down assays, and qRT-PCR. We found that miR-21 binding sites were present in circRNA_0026344 and, in HBE cells, it could act as a sponge for miR-21. When pcDNA3.0-circRNA_0026344, a high expression plasmid of circRNA_0026344, was transfected into HBE cells, the CSE-induced up-regulation of miR-21 levels was reversed. In MRC-5 cells, HBE-secreted exosomal miR-21 decreased levels of Smad7 and activated the TGF-β1/Smad3 pathway. By using the Targetscan database, the presence of species-conserved miR-21 binding sites in the Smad7 3'UTR region were predicted. We verified, by use of a luciferase reporter gene, that miR-21 bound to the 3'UTR region of Smad7 mRNA to inhibit its transcription. In conclusion, the results reveal that, in CS-induced pulmonary fibrosis, circRNA_0026344, via exosomal miR-21 regulation of Smad7, is involved in aberrant cross-talk of epithelium-fibroblasts. These results will be useful for the discovery of early biomarkers and for providing therapeutic targets for smoking-induced pulmonary fibrosis.

Construction of a circRNA-Related Prognostic Risk Score Model for Predicting the Immune Landscape of Lung Adenocarcinoma

The purpose of this study was to construct a circular RNA (circRNA)-related competing endogenous RNA (ceRNA) regulatory network and risk score model for lung adenocarcinoma (LUAD). The relationship of the risk score to immune landscape and sensitivity to chemotherapy and targeted therapy of LUAD was assessed. We downloaded mRNA and miRNA expression data, along with clinical information, from The Cancer Genome Atlas (TCGA) program, and circRNA expression data from the Gene Expression Omnibus (GEO) database and identified differently expressed circRNA (DEcircRNA), miRNA (DEmiRNA), and mRNA (DEmRNA) using R software. We then constructed the circRNA-related network using bioinformatics method. The risk score model was established by LASSO Cox regression analysis based on 10 hub genes. In addition, the risk score model was an independent predictor for overall survival (OS) in both the TCGA and CPTAC datasets. Patients in the high-risk group had shorter OS and disease-free survival (DFS) than those in the low-risk group and were more sensitive to chemotherapy and targeted therapy. The types of tumor-infiltrating immune cells were different in the high- and low-risk groups. Our data revealed that the circRNA-related risk score model is closely associated with the level of immune cell infiltration in the tumor and the effects of adjuvant treatment. This network may be useful in designing personalized treatments for LUAD patients.

Hsa_circ_0008234 facilitates proliferation of cutaneous squamous cell carcinoma through targeting miR-127-5p to regulate ADCY7

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin malignant tumor with 25-50% of 5-year survival. There exist urgent needs for the identification of novel biomarkers for the diagnostic and therapeutic strategies of cSCC. The differentially expressed circRNAs in cSCC tissues and non-lesional skin tissues were obtained through analyzing the circular RNAs (circRNAs) microarray dataset GSE74758. The expression pattern of the indicated circRNAs in cSCC tissues was confirmed by qRT-PCR. FISH analysis was used to detect the location of hsa_circ_0008234 in cells. RIP experiment was used to detect the interaction between hsa_circ_0008234 and miR-127-5p. CCK-8 analysis and colony formation assay were used to detect the proliferation of cSCC cells. qRT-PCR and western blot were adopted to detect the expression of ACDY7. Three differential expressed circRNAs were obtained from the microarray data (GSE74758), and hsa_circ_0008234 was confirmed to be highly expressed in cSCC tissues by qRT-PCR. Hsa_circ_0008234 was mainly located in cytoplasm and stable in cSCC cells. RIP experiment revealed that hsa_circ_0008234 directly interacts with miR-127-5p in cSCC cells. Hsa_circ_0008234 increased the cell viability and colony formation of cSCC cells through acting as the sponge of miR-127-5p. MiR-127-5p inhibited the expression of ADCY7 in cSCC cells through binding the 3'UTR of ADCY7. Hsa_circ_0008234 was positively associated with ADCY7 expression in cSCC tissues. Hsa_circ_0008234 facilitates the proliferation of cSCC through targeting miR-127-5p to regulate ADCY7 expression and has the potential to be a novel therapeutic target for cSCC.

Circular RNA circNEURL4 inhibits cell proliferation and invasion of papillary thyroid carcinoma by sponging miR-1278 and regulating LATS1 expression

Circular RNAs (circRNA) are found to be closely associated with cancers as their possibility as "sponges" to miRNAs, thus liberating the downstream target mRNA. However, deep research is still needed to study the function of circRNA in papillary thyroid carcinoma (PTC). Here, we sought to explore new circRNA which could play an important role in the development of PTC. We filtered candidate circRNAs based on microarray data from public database and verified the result using qRT-PCR. We performed CCK8 assay, colony formation assay, apoptosis assay, transwell assays, and xenograft experiments to explore the function of selected circRNA on PTC. We predicted the miRNA targets of the circRNA and the target gene of miRNA through bioinformatic analysis and validated the target by mutant experiments. And by the use of overexpression experiments, knockdown experiments, and the functional assays mentioned above, we figured out the pathway behind the selected circRNA. Based on our data, we found that circNEURL4 was significantly decreased in the PTC samples and lower expression of circNEURL4 was closely associated with a poor prognosis of patients with PTC. Then, we proved that circNEURL4 could inhibit cell proliferation and invasion of PTC in vivo and in vitro. Furthermore, we demonstrated that circNEURL4 may binding to miR-1278 and thus indirectly improving the expression of LATS1. Our findings revealed that circNEURL4 may probably serve as a diagnostic marker to predict PTC patients' prognosis and a possible therapeutic target to PTC via miR-1278/LATS1 axis.

circ0101675 promotes malignant process via sponging miR-1278 and upregulating WNT3A/5A in non-small cell lung cancer

Circular RNAs (circRNAs) is one type of non-coding RNAs (ncRNAs) which have many roles in biological processes, as well as modulation intracellular gene expression modulation. Nonethless, the roles along with expression status of the most circRNAs in NSCLC (non-small cell lung cancer) remain unknown. Herein, we conducted a high-throughput microarray sequencing to identify abnormal expressed circRNAs. Circ0101675 was found upregulated in NSCLC cell lines and tissues. We carried out colony formation, transwell, CCK-8, and animal assays to investigate the functions of circ0101675. Silence of circ0101675 inhibited the migration and proliferation of NSCLC. To elucidate the mechanism, RNA immunoprecipitation assays along with luciferase enzyme reporter assays were further employed to explore the cross-talk between circ0101675 and other molecules. We discovered that circ0101675 facilitates the malignant process of growth and migration via sponging miR-1278 and upregulating WNT3A/5A expression. In conclusion, we revelaed the vital role of circ0101675-miR-1278-WNT3A/5A signaling in NSCLC progression via the competing endogenous RNAs mechanism. Therefore, circ0101675 can be used as a new and useful biomarker for monitoring and treating NSCLC.

CircRNA circ_0092314 Induces Epithelial-Mesenchymal Transition of Pancreatic Cancer Cells via Elevating the Expression of S100P by Sponging miR-671

Background

Circular RNAs (circRNAs) is a novel class of non-coding RNAs that regulate gene expression during cancer progression. Circ_0092314 is a newly discovered circRNA that was upregulated in pancreatic cancer (PAAD) tissues. However, the detailed functions and underlying mechanisms of circ_0092314 in PAAD cells remain unclear.

Methods

We first determined the expression of circ_0092314 in PAAD and normal tissues and further investigated the functional roles of circ_0092314 in regulating epithelial-mesenchymal transition (EMT) of PAAD cells. We also assessed the regulatory action of circ_0092314 on the microRNA-671 (miR-671) and its target S100P.

Results

Circ_0092314 was markedly upregulated in PAAD tissues and cells, and its overexpression was closely correlated with worse prognosis of PAAD patients. Functionally, circ_0092314 promotes proliferation, invasion and EMT in vitro and tumor growth in vivo. Mechanistically, we demonstrated that circ_0092314 directly binds to miR-671 and relieve its suppression of the downstream target S100P, which induces EMT and activates the AKT signaling pathway. The tumor-promoting effects caused by overexpression of circ_0092314 could be revered by re-expression of miR-671 in PAAD cells.

Conclusions

Overall, our study demonstrates that circ_0092314 exerts critical roles in promoting the EMT features of PAAD cells, and provides insight into how elevated expression of circ_0092314 might influence PAAD progression.

The effect of microRNA-330 replacement on inhibition of growth and migration in renal cancer cells

This study was conducted to scrutinize microRNA-330 (miR-330) role in growth, migration, and the expression of metastatic genes in renal cell carcinoma (RCC) in vitro. Following transfection of the cells with miR-330 mimic, cell proliferation using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell migration by wound healing assay, and apoptosis by flow cytometry were evaluated. Quantitative real-time PCR was conducted to assess expression levels of matrix metalloproteinase 2 (MMP2), MMP9, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS), Kirsten rat sarcoma virus (K-Ras), cellular Myc (c-Myc), and C-X-C chemokine receptor type 4 (CXCR-4) as metastatic genes in the progression of RCC. Results showed that miR-330 was downregulated in the Caki-1 cells compared with HK-2 cells (p < 0.001). Upregulation of miR-330 obstructed in vitro expansion and migration, while it intensified apoptosis rate in the Caki-1 cells. Moreover, it was found that miR-330 transfection negatively modulated the expression of MMP2, MMP9, ADAMTS, K-Ras, c-Myc, and CXCR-4 in the Caki-1 cells. Our findings revealed that overexpression of miR-330 might provide an auxiliary treatment approach for overcoming invasion, progression, and metastasis in patients with RCC by enhancing cell apoptosis.

Circ_0035483 Functions as a Tumor Promoter in Renal Cell Carcinoma via the miR-31-5p-Mediated HMGA1 Upregulation

Background

Renal cell carcinoma (RCC) that originates from the proximal renal tubules is the most common cancer of the human kidney. Increasing circRNA/miRNA/mRNA networks have been found in RCC regulation. This study will explore the regulatory relation of circular RNA (circRNA) circ_0035483, microRNA-31-5p (miR-31-5p) and high mobility group A1 (HMGA1).

Methods

The levels of circ_0035483, miR-31-5p and HMGA1 were measured by real-time polymerase chain reaction (qRT-PCR) or Western blot. Cell proliferation was determined using Cell Counting Kit-8 (CCK-8) and colony formation assays. Cell migration and invasion were assessed by transwell assay. HMGA1 and epithelial–mesenchymal transition (EMT)-related protein levels were quantified using Western blot. Glycolytic metabolism was evaluated by glucose consumption and lactate production. The interaction between targets was confirmed via dual-luciferase reporter, RNA immunoprecipitation (RIP) and RNA pull-down assays. In vivo experiment was performed through the establishment of xenograft models in mice.

Results

Circ_0035483 expression was upregulated in RCC tissues and cells. The inhibitory effects on RCC cell proliferation, migration, invasion, EMT and glycolysis were induced after circ_0035483 was downregulated. MiR-31-5p was identified as a target of circ_0035483 and miR-31-5p upregulation was related to the function of circ_0035483 knockdown in RCC cells. Additionally, miR-31-5p targeted HMGA1 and inhibited the malignant behaviors of RCC cells by negatively regulating HMGA1. Moreover, HMGA1 expression was regulated by circ_0035483 via targeting miR-31-5p. Circ_0035483 also affected tumor growth in vivo by relying on the miR-31-5p/HMGA1 axis.

Conclusion

These findings clarified that the tumor-promoting function of circ_0035483 in RCC was partly achieved by regulating the miR-31-5p/HMGA1 axis.

Circular RNA circ-CCAC1 Facilitates Adrenocortical Carcinoma Cell Proliferation, Migration, and Invasion through Regulating the miR-514a-5p/C22orf46 Axis

Adrenocortical carcinoma (ACC) is a rare but clinically aggressive endocrine malignancy. Circular RNAs (circRNAs) were found to play key roles in tumorigenesis. In the current study, we aimed to investigate the functions and mechanisms of a novel circRNA, circ-CCAC1, in ACC cells. circ-CCAC1 expression levels in ACC tissue specimens and cell lines were evaluated by RT-qPCR. Kaplan-Meier analysis was applied to explore the relationship between circ-CCAC1 and patients' prognosis. Cell counting kit-8 (CCK-8), colony formation, acridine orange/ethidium bromide (AO/EB) double fluorescence staining, and Transwell assays were performed to evaluate the functions of circ-CCAC1 in ACC cells. Bioinformatics analysis and a dual-luciferase reporter assay were utilized to explore the mechanisms of circ-CCAC1. As a result, circ-CCAC1 was overexpressed in ACC tissue samples and cell lines and correlated with poor prognosis. Gain- and loss-of-function tests demonstrated that circ-CCAC1 acted as an oncogene in ACC. What is more, circ-CCAC1 enhanced C22orf46 expression by sponging miR-514a-5p in ACC cells. A rescue assay illustrated that circ-CCAC1 facilitated ACC progression through miR-514a-5p/C22orf46 signaling. To sum up, we identified a novel circRNA, circ-CCAC1, which may be used as a potential therapeutic target for ACC.