Hsa_circ_0084927 Regulates Cervical Cancer Advancement via Regulation of the miR-634/TPD52 Axis

Circular RNA circEZH2 Promotes Lung Adenocarcinoma Progression by Regulating microRNA-495-3p/Tumor Protein D52 Axis and Activating Nuclear Factor-Kappa B Pathway

Background

It has been increasingly recognized that circular RNAs (circRNAs) act as a pivotal factor in the onset and progression of human malignancies. Yet, the specific activities and mechanistic roles of these RNAs in the context of lung adenocarcinoma (LUAD) are not fully understood.

Methods

Microarray analysis identified a novel LUAD-associated circular RNA, termed hsa_circ_0006357 (also referred to as circEZH2). Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was utilized for the analysis of circEZH2 expression in tissues and cell lines. The characteristics of circEZH2 were verified by RNase R treatment and fluorescence in situ hybridization (FISH) assays. The functions of circEZH2 were detected by Cell Counting Kit-8 (CCK-8), colony formation, wound healing, and Transwell assays. The molecular mechanism of circEZH2 was clarified through bioinformatics analysis as well as RNA pulldown, dual-luciferase reporter, RT-qPCR, and immunoblotting assays. The role of circEZH2 in vivo was investigated using a xenograft model.

Results

This investigation revealed that circEZH2 expression was elevated in LUAD cell lines and tumor samples. This elevation was associated with enhanced cell proliferation, migratory capacity, epithelial-mesenchymal transition (EMT), and invasion in vitro. Conversely, silencing of circEZH2 in vivo resulted in a notable decrease in LUAD tumorigenesis, whereas its overexpression led to the opposite effects. Mechanistically, circEZH2 appeared to act as a sponge for miR-495-3p, facilitating the upregulation of tumor protein D52 (TPD52) and triggering the nuclear factor kappa B (NF-κB) signaling pathway, thus contributing to the progression of LUAD.

Conclusion

These findings indicate that circEZH2 may function as a competitive endogenous RNA (ceRNA), driving the progression of LUAD by manipulating the miR-495-3p/TPD52 axis and activating the NF-κB pathway.

Hsa_circ_0000069 Accelerates Cervical Cancer Progression by Sponging miR-1270 to Facilitate CPEB4 Expression

The critical importance of circular RNAs (circRNAs) in human cancers, including cervical cancer (CC), has been discovered in recent years. However, the function and mechanism of hsa_circ_0000069 (circ_0000069) in CC have been fully understood. The expression levels of circ_0000069, microRNAs (miR-1270, miR-1276 and miR-620) and cytoplasmic polyadenylation element binding protein 4 (CPEB4) mRNA were detected by quantitative real time polymerase chain reaction (qRT-PCR). Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, transwell and tube formation assays were used to clarify the effects of circ_0000069 on the functional behaviors of CC cells. The binding relationships among miR-1270, circ_0000069 and CPEB4 were detected by dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. A xenograft tumor model was established to explore the effect of circ_0000069 on tumor growth in vivo. Circ_0000069 was upregulated in CC clinical samples and cell lines, and its expression was associated with the clinical stage of CC patients. Circ_0000069 knockdown significantly decreased cell proliferation, invasion, migration, and tube formation and increased cell apoptosis in vitro. Moreover, miR-1270 was a direct target of circ_0000069, and CPEB4 was the downstream target of miR-1270. Knockdown of miR-1270 reversed the inhibitory effect of circ_0000069 knockdown on CC progression, and CPEB4 overexpression overturned the effect of miR-1270 on CC progression. In xenograft experiments, the oncogenic effect of circ_0000069 on tumor growth was verified. Altogether, circ_0000069 adsorbed miR-1270 to upregulate CPEB4 expression, thereby promoting the malignant phenotypes of CC cells. Circ_0000069 might be a potential target for treatment of CC.

Circular RNAs in Cell Cycle Regulation of Cancers

Cancer has been one of the most problematic health issues globally. Typically, all cancers share a common characteristic or cancer hallmark, such as sustaining cell proliferation, evading growth suppressors, and enabling replicative immortality. Indeed, cell cycle regulation in cancer is often found to be dysregulated, leading to an increase in aggressiveness. These dysregulations are partly due to the aberrant cellular signaling pathway. In recent years, circular RNAs (circRNAs) have been widely studied and classified as one of the regulators in various cancers. Numerous studies have reported that circRNAs antagonize or promote cancer progression through the modulation of cell cycle regulators or their associated signaling pathways, directly or indirectly. Mostly, circRNAs are known to act as microRNA (miRNA) sponges. However, they also hold additional mechanisms for regulating cellular activity, including protein binding, RNA-binding protein (RBP) recruitment, and protein translation. This review will discuss the current knowledge of how circRNAs regulate cell cycle-related proteins through the abovementioned mechanisms in different cancers.

Long noncoding RNA FTX promotes epithelial-mesenchymal transition of epithelial ovarian cancer through modulating miR-7515/TPD52 and activating Met/Akt/mTOR

Overexpressed long noncoding RNA FTX is associated with low survival rate of epithelial ovarian cancer (EOC) patients, and enhances tumor infiltration. Thus, we aim to illuminate the undefined underlying mechanisms. Real-time quantitative polymerase chain reaction was applied to detect the expressions of FTX, miR-7515, miR-342-3p, miR-940, miR-150-5p, miR-205-5p and tumor protein D52 (TPD52). Cell counting kit-8 and transwell assays were utilized to explore the cell viability, migration or invasion of EOC cells. Western blot was conducted to measure the expressions of E-cadherin, N-cadherin, Met, phosphorylated (p)-Met, Akt, p-Akt, mTOR and p-mTOR. LncBase and TargetScan predicted the binding of miR-7515 with FTX, and the binding of TPD52 with miR-7515, respectively. The two bindings were further validated by dual luciferase reporter assay. As a result, FTX sponged miR-7515 and miR-7515 targeted to TPD52. FTX was overexpressed in four EOC cell lines. Overexpressed FTX enhanced the cell viability, migration or invasion of EOC cells, elevated N-cadherin and TPD52 expressions, phosphorylated Met/Akt/mTOR, and inhibited E-cadherin expression. All these influences were subsequently reversed by miR-7515 mimic. Collectively, FTX regulates miR-7515/TPD52 to facilitate the migration, invasion or epithelial-mesenchymal transition of EOC through activating Met/Akt/mTOR signaling pathway.

Hsa_circ_0001658 accelerates the progression of colorectal cancer through miR-590-5p/METTL3 regulatory axis

BACKGROUND

As reported, multiple circular RNAs (circRNAs) interfere with colorectal cancer (CRC) progression. Here, circRNA_0001658 (circ_0001658) is focused on studying how it works in CRC.

AIM

Clarify the expression pattern, biological function, and underlying mechanism of circ_0001658 of CRC tumorigenesis.

METHODS

In CRC-related chip data retrieved using the database named Gene Expression Omnibus, different expressions of circRNAs between CRC and normal tissue samples were identified. Quantitative Real-time PCR and Western blot ensured the analysis on circ_0001658, microRNA-590-5P (miR-590-5p), and methyltransferase-like 3 (METTL3) mRNA expressions in tissues and cells. Cell counting kit-8 and flow cytometry were used to detect cell proliferation, apoptosis and migration. The targeting relations between circ_0001658, miR-590-5p, and METTL3 mRNA 3'-untranslated region were under the verification of bioinformatics prediction and dual luciferase-based reporter gene assays. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were employed on the downstream targets of miR-590-5p using the Database for Annotation, Visualization and Integrated Discovery database.

RESULTS

Circ_0001658 and METTL3 mRNA was elevated in CRC tissues and cells, whereas miR-590-5p was decreased. Circ_0001658 overexpression promoted the proliferation of HT29 cells, inhibited apoptosis, and accelerated the cell cycle. In SW480 cells, knocking down circ_0001658 had the opposite effect. Circ_0001658 could specifically bind to miR-590-5p and negatively modulate its expressions; METTL3 is a miR-590-5p target that can be positively regulated by circ 0001658. Circ 0001658 was inversely associated with miR-590-5p expression while positively with METTL3 expressions.

CONCLUSION

Circ_0001658 regulates the miR-590-5p/METTL 3-axis to increase CRC cell growth and decrease apoptosis.

Circ_0060551 promotes the migration and invasion of cervical cancer by Up-regulating TPD52

PROBLEM

Cervical cancer has been recognized as the second most common cancer in women worldwide. Previous studies have reported that some circular RNAs (circRNAs) can influence the progression of cervical cancer. However, more researches are still required to unveil the underlying mechanism of how circRNAs regulate the progression of such cancer. We aimed at unveiling the mechanism of how circ_0060551 effected the progression of cervical cancer.

METHOD OF STUDY

RT-qPCR and western blot assays were used to detect the expression and protein levels. Mechanism experiments were conducted to investigate the relationship among circ_0060551, TPD52, miR-520a-5p and ELAVL1. Rescue assays were mainly carried out to verify how circ_0060551 influenced the migration and invasion of cervical cancer cells.

RESULTS

According to the results, circ_0060551 was up-regulated in cervical cancer cells and could promote the migration and invasion of cells via TPD52. In addition, circ_0060551 could up-regulate TPD52 expression through a ceRNA model to target miR-520a-5p. Moreover, circ_0060551 could stabilize the mRNA expression of TPD52 via recruiting ELAVL1.

CONCLUSION

Our study proved that circ_0060551 could promote the migration and invasion of cervical cancer cells. This article is protected by copyright. All rights reserved.

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.

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.

CircRNA_0084927 promotes colorectal cancer progression by regulating miRNA-20b-3p/glutathione S-transferase mu 5 axis

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer and the second most common cause of cancer-related death worldwide. The 5-year survival rate of patients with early-stage CRC could reach 90%, but it is very low in patients with advanced-stage CRC. Recent studies have shown that circular RNAs play important roles in regulating the migration and invasion of CRC cells.

AIM

To elucidate the role of circRNA_0084927 (circ_0084927) in the migration and invasion of CRC cells and its underlying mechanism.

METHODS

Clinical tissue samples and cells were collected, and the expression of circ_0084927 was detected by quantitative polymerase chain reaction (qPCR). The diagnostic performance of circ_0084927 was assessed by receiver operating characteristic curve analysis. The role of circ_0084927 in CRC cell proliferation, migration, and invasion was determined using cell counting kit-8 assay, wound healing assay, and transwell assay, respectively. The regulatory relationship among circ_0084927, miRNA-20b-3p (miR-20b-3p), and glutathione S-transferase mu 5 (GSTM5) was identified using databases, luciferase reporter assay, qPCR, and Western blot analysis. AKT-mTOR signaling was also verified after circ_0084927 knockdown or miR-20b-3p mimic treatment.

RESULTS

The expression of circ_0084927 was significantly increased in CRC tissues and cells, and it was higher in advanced-stage CRC compared with early-stage CRC. The area under the curve (AUC) of circ_0084927 was 0.806 [95% confidence interval (CI): 0.683-0.896]. In addition, the AUC was 0.874 (95%CI: 0.738-0.956) in patients with advanced-stage CRC and 0.713 (95%CI: 0.555-0.840) in those with early-stage CRC. Knockdown of circ_0084927 inhibited the migration and invasion of HCT116 cells. Moreover, circ_0084927 was found to act as a sponge of miR-20b-3p. MiR-20b-3p activation reduced the circ_0084927 level, whereas miR-20b-3p inhibition increased the circ_0084927 level. But the effect was not found after circ_0084927 mutation. In addition, miR-20b-3p expression in CRC patients was also reduced and negatively correlated with circ_0084927 expression. The function of circ_0084927 in HCT116 cells with circ_0084927 knockdown was rescued by miR-20b-3p. Moreover, GSTM5 expression was significantly decreased after overexpressing miR-20b-3p or inhibiting circ_0084927, but its expression was rescued when circ_0084927 and miR-20b-3p were both inhibited. Finally, AKT-mTOR signaling was markedly regulated by circ_0084927 and miR-20b-3p.

CONCLUSION

The expression of circ_0084927 is significantly increased in CRC and higher in advanced-stage CRC than in early-stage CRC. Moreover, circ_0084927 potentially regulates CRC cell migration and invasion via the miR-20b-3p/GSTM5/ AKT/mTOR pathway.

Knockdown of circRNA_0007534 suppresses the tumorigenesis of cervical cancer via miR-206/GREM1 axis

BACKGROUND

Increasing evidence manifested that circular RNAs (circRNAs) acted as crucial regulators in human cancers by targeting the miRNA/mRNA axis, including cervical cancer (CC). Circ_0007534 was reported to promote CC cell proliferation and invasion by the miR-498/BMI-1 axis. The aim of this study was to explore a novel miRNA/mRNA network underlying circ_0007534 in CC regulation.

METHODS

The quantitative real-time polymerase chain reaction (qRT-PCR) was implemented to examine the levels of circ_0007534, miR-206 and Gremlin1 (GREM1). Cell viability was determined using MTT assay. BrdU and colony formation assays were performed for analyzing cell proliferation. Cell apoptosis was assessed by flow cytometry. The protein levels of GREM1 and apoptotic markers (Bcl-2, Bax, C-Caspase3) were measured via western blot. Cell invasion was detected by transwell assay. The target relationship was analyzed by dual-luciferase reporter assay. The impact of circ_0007534 on CC growth in vivo was ascertained by xenograft assay.

RESULTS

Circ_0007534 expression was aberrantly increased in CC tissues and cells. Functionally, knockdown of circ_0007534 reduced CC cell growth and invasion but motivated apoptosis. In the mechanism, circ_0007534 targeted miR-206 and its regulatory function was associated with sponging miR-206. Moreover, circ_0007534 was found to regulate GREM1 level by targeting miR-206. The inhibitory effect of si-circ_0007534 on the malignant progression of CC was reversed after GREM1 was overexpressed. Furthermore, circ_0007534 inhibition also reduced tumor growth of CC in vivo partially by regulating miR-206/GREM1 axis.

CONCLUSION

These results suggested that knockdown of circ_0007534 promoted the level of miR-206 to induce the expression downregulation of GREM1, consequently inhibiting the progression of CC.