Potential Significance of Circular RNA in Human Placental Tissue for Patients with Preeclampsia

Aims: This study aimed to identify the different expression of circular RNAs (circRNAs) in the placental tissues of pregnant women with preeclampsia (PE) and to provide a new avenue of research regarding the pathological mechanisms of PE. Methods: In this study, we collected 40 placental tissues from PE patients and 35 placental tissues from gestational age-matched patients who gave premature birth. Arraystar circRNA Microarray Technology (KANGCHEN, Shanghai, China) was used to analyze the differential expression of circRNAs. According to the basic content of circRNAs in the two groups and their fold changes and due to the practicability of the designed divergent primers of each candidate circRNA, we selected three up-regulated circRNAs, hsa_circRNA_100782, hsa_circRNA_102682 and hsa_circRNA_104820, to validate the data. Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) was utilized to estimate the Ct values in both groups. We further evaluated the differences with a paired t-test and a receiver operating characteristic (ROC) curve. Results: Many circRNAs were found to be differentially expressed in PE placental tissues versus their controls; of these, 143 circRNAs were up-regulated and 158 were down-regulated. The expression levels of hsa_circRNA_100782 (p < 0.05), hsa_circRNA_102682 (p < 0.05), and hsa_circRNA_104820 (p < 0.0001) were validated as significantly up-regulated in the experimental group compared with the controls. Finally, we performed a literature comparison to forecast the possible mechanisms of circRNA function during PE. Conclusion: circRNA expression significantly differed in placental PE tissues compared with controls. According to the circRNA microarray results and the existing papers, circRNAs may contribute to the pathogenesis of PE by acting as miRNA sponges; this possibility requires additional investigation in future studies.

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The effective function of circular RNA in colorectal cancer

Cancer Cell International ◽

10.1186/s12935-021-02196-0 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Mandana Ameli-Mojarad ◽

Melika Ameli-Mojarad ◽

Mahrooyeh Hadizadeh ◽

Chris Young ◽

Hosna Babini ◽

...

Keyword(s):

Colorectal Cancer ◽

Molecular Mechanisms ◽

Rna Binding ◽

Rna Binding Proteins ◽

Circular Rna ◽

Circular Rnas ◽

Colorectal Tumorigenesis ◽

Non Coding Rnas ◽

Mirna Sponges ◽

Mechanisms Of Development

AbstractColorectal cancer (CRC) is the 3rd most common type of cancer worldwide. Late detection plays role in one-third of annual mortality due to CRC. Therefore, it is essential to find a precise and optimal diagnostic and prognostic biomarker for the identification and treatment of colorectal tumorigenesis. Covalently closed, circular RNAs (circRNAs) are a class of non-coding RNAs, which can have the same function as microRNA (miRNA) sponges, as regulators of splicing and transcription, and as interactors with RNA-binding proteins (RBPs). Therefore, circRNAs have been investigated as specific targets for diagnostic and prognostic detection of CRC. These non-coding RNAs are also linked to metastasis, proliferation, differentiation, migration, angiogenesis, apoptosis, and drug resistance, illustrating the importance of understanding their involvement in the molecular mechanisms of development and progression of CRC. In this review, we present a detailed summary of recent findings relating to the dysregulation of circRNAs and their potential role in CRC.

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The Regulatory Functions of Circular RNAs in Digestive System Cancers

Cancers ◽

10.3390/cancers12030770 ◽

2020 ◽

Vol 12 (3) ◽

pp. 770 ◽

Cited By ~ 4

Author(s):

Xiao Yuan ◽

Ya Yuan ◽

Zhi He ◽

Diyan Li ◽

Bo Zeng ◽

...

Keyword(s):

Digestive System ◽

Rna Binding ◽

Rna Binding Proteins ◽

Circular Rna ◽

Research Progress ◽

Circular Rnas ◽

Biological Functions ◽

Ribonucleic Acids ◽

Mirna Sponges ◽

And Biological Markers

Circular ribonucleic acids (circRNAs), which are a type of covalently closed circular RNA, are receiving increasing attention. An increasing amount of evidence suggests that circRNAs are involved in the biogenesis and development of multiple diseases such as digestive system cancers. Dysregulated circRNAs have been found to act as oncogenes or tumour suppressors in digestive system cancers. Moreover, circRNAs are related to ageing and a wide variety of processes in tumour cells, such as cell apoptosis, invasion, migration, and proliferation. Moreover, circRNAs can perform a remarkable multitude of biological functions, such as regulating splicing or transcription, binding RNA-binding proteins to enable function, acting as microRNA (miRNA) sponges, and undergoing translated into proteins. However, in digestive system cancers, circRNAs function mainly as miRNA sponges. Herein, we summarise the latest research progress on biological functions of circRNAs in digestive system cancers. This review serves as a synopsis of potential therapeutic targets and biological markers for digestive system cancer.

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Identification of differentially expressed circular RNAs in human colorectal cancer

Tumor Biology ◽

10.1177/1010428317694546 ◽

2017 ◽

Vol 39 (3) ◽

pp. 101042831769454 ◽

Cited By ~ 31

Author(s):

Peili Zhang ◽

Zhigui Zuo ◽

Wenjing Shang ◽

Aihua Wu ◽

Ruichun Bi ◽

...

Keyword(s):

Colorectal Cancer ◽

Receiver Operating Characteristic ◽

Operating Characteristic ◽

Circular Rna ◽

Expression Level ◽

Circular Rnas ◽

Human Colorectal Cancer ◽

Expression Levels ◽

Normal Tissues ◽

Node Metastasis

Circular RNA, a class of non-coding RNA, is a new group of RNAs and is related to tumorigenesis. Circular RNAs are suggested to be ideal candidate biomarkers with potential diagnostic and therapeutic implications. However, little is known about their expression in human colorectal cancer. In our study, differentially expressed circular RNAs were detected using circular RNA array in paired tumor and adjacent non-tumorous tissues from six colorectal cancer patients. Expression levels of selected circular RNAs (hsa_circRNA_103809 and hsa_circRNA_104700) were measured by real-time polymerase chain reaction in 170 paired colorectal cancer samples for validation. Statistical analyses were conducted to investigate the association between hsa_circRNA_103809 and hsa_circRNA_104700 expression levels and respective patient clinicopathological features. Receiver operating characteristic curve was constructed to evaluate the diagnostic values. Our results indicated that there were 125 downregulated and 76 upregulated circular RNAs in colorectal cancer tissues compared with normal tissues. We also first demonstrated that the expression levels of hsa_circRNA_103809 ( p < 0.0001) and hsa_circRNA_104700 ( p = 0.0003) were significantly lower in colorectal cancer than in normal tissues. The expression level of hsa_circRNA_103809 was significantly correlated with lymph node metastasis ( p = 0.021) and tumor-node-metastasis stage ( p = 0.011), and the expression level of hsa_circRNA_104700 was significantly correlated with distal metastasis ( p = 0.036). The area under receiver operating characteristic curves of hsa_circRNA_103809 and hsa_circRNA_104700 were 0.699 ( p < 0.0001) and 0.616 ( p < 0.0001), respectively. In conclusion, these results suggest that hsa_circRNA_103809 and hsa_circRNA_104700 may be potentially involved in the development of colorectal cancer and serve as potential biomarkers for the diagnosis of colorectal cancer.

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Circular RNAs in Cardiovascular Disease: An Overview

BioMed Research International ◽

10.1155/2017/5135781 ◽

2017 ◽

Vol 2017 ◽

pp. 1-9 ◽

Cited By ~ 66

Author(s):

Ximin Fan ◽

Xinyu Weng ◽

Yifan Zhao ◽

Wei Chen ◽

Tianyi Gan ◽

...

Keyword(s):

Gene Expression ◽

Cardiovascular Disease ◽

Cardiovascular Diseases ◽

Noncoding Rna ◽

Essential Role ◽

Closed Loop ◽

Regulation Of Gene Expression ◽

Circular Rna ◽

Circular Rnas ◽

Mirna Sponges

Circular RNA (circRNA), a novel type of endogenous noncoding RNA (ncRNA), has become a research hotspot in recent years. CircRNAs are abundant and stably exist in creatures, and they are found with covalently closed loop structures in which they are quite different from linear RNAs. Nowadays, an increasing number of scientists have demonstrated that circRNAs may have played an essential role in the regulation of gene expression, especially acting as miRNA sponges, and have described the potential mechanisms of several circRNAs in diseases, hinting at their clinical therapeutic values. In this review, the authors summarized the current understandings of the biogenesis and properties of circRNAs and their functions and role as biomarkers in cardiovascular diseases.

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Circular RNA MCTP2 inhibits cisplatin resistance in gastric cancer by miR-99a-5p-mediated induction of MTMR3 expression

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-020-01758-w ◽

2020 ◽

Vol 39 (1) ◽

Author(s):

Guangli Sun ◽

Zheng Li ◽

Zhongyuan He ◽

Weizhi Wang ◽

Sen Wang ◽

...

Keyword(s):

Gastric Cancer ◽

Xenograft Model ◽

Circular Rna ◽

Luciferase Reporter ◽

Circular Rnas ◽

Mouse Xenograft Model ◽

Mirna Sponges ◽

High Level

Abstract Background Cisplatin (CDDP) is the first-line chemotherapy for gastric cancer (GC). The poor prognosis of GC patients is partially due to the development of CDDP resistance. Circular RNAs (circRNAs) are a subclass of noncoding RNAs that function as microRNA (miRNA) sponges. The role of circRNAs in CDDP resistance in GC has not been evaluated. Methods RNA sequencing was used to identify the differentially expressed circRNAs between CDDP-resistant and CDDP-sensitive GC cells. qRT-PCR was used to detect the expression of circMCTP2 in GC tissues. The effects of circMCTP2 on CDDP resistance were investigated in vitro and in vivo. Pull-down assays and luciferase reporter assays were performed to confirm the interactions among circMCTP2, miR-99a-5p, and myotubularin-related protein 3 (MTMR3). The protein expression levels of MTMR3 were detected by western blotting. Autophagy was evaluated by confocal microscopy and transmission electron microscopy (TEM). Results CircMCTP2 was downregulated in CDDP-resistant GC cells and tissues compared to CDDP-sensitive GC cells and tissues. A high level of circMCTP2 was found to be a favorable factor for the prognosis of patients with GC. CircMCTP2 inhibited proliferation while promoting apoptosis of CDDP-resistant GC cells in response to CDDP treatment. CircMCTP2 was also found to reduce autophagy in CDDP-resistant GC cells. MiR-99a-5p was verified to be sponged by circMCTP2. Inhibition of miR-99a-5p could sensitize GC cells to CDDP. MTMR3 was confirmed to be a direct target of miR-99a-5p. Knockdown of MTMR3 reversed the effects of circMCTP2 on the proliferation, apoptosis and autophagy of CDDP-resistant GC cells. CircMCTP2 was also confirmed to inhibit CDDP resistance in vivo in a nude mouse xenograft model. Conclusions CircMCTP2 sensitizes GC to CDDP through the upregulation of MTMR3 by sponging miR-99a-5p. Overexpression of CircMCTP2 could be a new therapeutic strategy for counteracting CDDP resistance in GC.

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Downregulated Expression of hsa_circ_0005556 in Gastric Cancer and Its Clinical Significance

Disease Markers ◽

10.1155/2019/2624586 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Liangwei Yang ◽

Yu Yu ◽

Xiuchong Yu ◽

Jiaming Zhou ◽

Zhiping Zhang ◽

...

Keyword(s):

Gastric Cancer ◽

Roc Curve ◽

Noncoding Rna ◽

Operating Characteristic ◽

Diagnostic Value ◽

Circular Rnas ◽

Normal Tissues ◽

Potential Biomarker ◽

Polymerase Chain

Background. Gastric cancer (GC) has a poor prognosis due to the lack of ideal tumor markers. Circular RNAs (circRNAs) are a novel type of noncoding RNA related to the occurrence of GC. Among our research, we investigated the role of hsa_circ_0005556 in GC. Materials and Methods. The expression of hsa_circ_0005556 of 100 paired GC tissues and adjacent normal tissues was detected using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). A receiver operating characteristic (ROC) curve was established to evaluate the diagnostic value of hsa_circ_0005556. The correlation between the expression of hsa_circ_0005556 and corresponding clinicopathological characteristic was explored. Results. hsa_circ_0005556 was significantly downregulated in GC tissues contrasted with adjacent normal tissues (n=100, p<0.001). The areas under the ROC curve (AUC) of hsa_circ_0005556 were up to 0.773, while 64% sensitivity and 82% specificity, respectively. Moreover, its expression levels were significantly associated with differentiation (p=0.001), TNM stage (p=0.013), and lymphatic metastasis (p=0.039). GC patients of high hsa_circ_0005556 levels had a longer overall survival (OS) than those of the low group (p=0.047). Conclusion. hsa_circ_0005556 is a potential biomarker for GC, which may guide judgment of the indication of endoscopic treatment for early gastric cancer (EGC).

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Simple method for extracting RNA from cultured cells and tissue with guanidine salts

Clinical Chemistry ◽

10.1093/clinchem/39.7.1408 ◽

1993 ◽

Vol 39 (7) ◽

pp. 1408-1411 ◽

Cited By ~ 20

Author(s):

R Zolfaghari ◽

X Chen ◽

E A Fisher

Keyword(s):

Cultured Cells ◽

Guanidine Hydrochloride ◽

Placental Tissue ◽

Animal Origin ◽

Clinical Samples ◽

Simple Method ◽

Simple Protocol ◽

Human Placental Tissue ◽

Polymerase Chain

Abstract We have developed a simple protocol for isolating RNA from both cell culture and tissue from human and animal sources, using guanidine thiocyanate and guanidine hydrochloride, but no organic solvents. The protocol reproducibly yielded 15 to 25 micrograms of high-quality RNA per 10(6) cells of human and animal origin and 1 to 1.1 mg of RNA per gram of human placental tissue. The RNA so obtained was ribonuclease-free and not contaminated by DNA. It was suitable for reverse transcription-polymerase chain reaction, Northern blot analysis, and in vitro expression of proteins. Thus, the molecular assessment of both research and clinical samples can be readily and reliably initiated by the application of this protocol.

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Circular RNA Expression Profile of Pancreatic Ductal Adenocarcinoma Revealed by Microarray

Cellular Physiology and Biochemistry ◽

10.1159/000453186 ◽

2016 ◽

Vol 40 (6) ◽

pp. 1334-1344 ◽

Cited By ~ 57

Author(s):

Haimin Li ◽

Xiaokun Hao ◽

Huimin Wang ◽

Zhengcai Liu ◽

Yong He ◽

...

Keyword(s):

Pancreatic Ductal Adenocarcinoma ◽

Expression Profile ◽

Mammalian Cells ◽

Noncoding Rna ◽

Circular Rna ◽

Pathological Process ◽

Ductal Adenocarcinoma ◽

Circular Rnas ◽

Normal Tissues ◽

Polymerase Chain

Background/Aims: Circular RNAs (circRNAs) are a special novel type of a stable, diverse and conserved noncoding RNA in mammalian cells. Particularly in cancer, circRNAs have been reported to be widely involved in the physiological/pathological process of life. However, it is unclear whether circRNAs are specifically involved in pancreatic ductal adenocarcinoma (PDAC). Methods: We investigated the expression profile of circRNAs in six PDAC cancer samples and paired adjacent normal tissues using microarray. A high-throughput circRNA microarray was used to identify dysregulated circular RNAs in six PDAC patients. Bioinformatic analyses were applied to study these differentially expressed circRNAs. Furthermore, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was performed to confirm these results. Results: We revealed and confirmed that a number of circRNAs were dysregulated, which suggests a potential role in pancreatic cancer. Conclusions: this study demonstrates that clusters of circRNAs are aberrantly expressed in PDAC compared with normal samples and provides new potential targets for the future treatment of PDAC and novel insights into PDAC biology.

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A 3-circular RNA signature as a noninvasive biomarker for diagnosis of colorectal cancer

Cancer Cell International ◽

10.1186/s12935-019-0995-7 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 9

Author(s):

Dao-xiong Ye ◽

Si-si Wang ◽

Ying Huang ◽

Pan Chi

Keyword(s):

Colorectal Cancer ◽

Roc Curves ◽

Circular Rna ◽

Diagnostic Value ◽

Differentially Expressed ◽

Circular Rnas ◽

Qrt Pcr ◽

Noninvasive Biomarker ◽

Proliferation And Metastasis ◽

Polymerase Chain

Abstract Background Circular RNAs (circRNAs), a novel type of noncoding RNAs, play critical roles in the initiation and progression of cancer. Emerging studies also shows that circRNAs may function as potential markers for cancer diagnosis and treatment. However, the diagnostic value of circRNAs in colorectal cancer (CRC) remains need to be unearthed. Methods CircRNA microarray was performed to detect the differentially expressed circRNAs in eight plasma samples, including four colorectal cancer (CRC) and four normal samples. Besides, the results of microarray were validated by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, ROC curve evaluation was performed to calculate the diagnostic value of significantly dysregulated circRNAs. In order to predict the potential mechanism of the significant circRNAs, circRNA–miRNA–mRNA network was constructed based on the TargetScan, miRTarBase and MIRDB database, as well as CircInteractome online software. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to further predict the function of meaningful circRNAs. Results Totally three differentially expressed circRNAs were identified in CRC plasma compared to normal plasma by circRNA microarray analysis, and the results was validated by qRT-PCR. Hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445 were identified and ROC curves analysis was used to calculate the single and joint diagnostic value. Furthermore, GO and KEGG analyses revealed that functions were mainly cancer-related, which indicated that the circRNAs were meaningfully associated with CRC cell proliferation and metastasis. Conclusion In conclusion, we have identified three circRNAs that are dysregulated in CRC plasma, including hsa_circ_0082182, hsa_circ_0000370 and hsa_circ_0035445. ROC curves showed that these circRNAs might have diagnostic value for colorectal cancer. Furthermore, bioinformatics analysis indicated that the above-mentioned circRNAs might be involved in the development of CRC.

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FUCHS - Towards full circular RNA characterization using RNAseq

10.7287/peerj.preprints.2418 ◽

2016 ◽

Author(s):

Franziska Metge ◽

Lisa F Czaja-Hasse ◽

Richard Reinhardt ◽

Chistoph Dieterich

Keyword(s):

Splice Site ◽

Developmental Stages ◽

Computational Prediction ◽

Break Point ◽

Circular Rna ◽

Circular Rnas ◽

Functional Studies ◽

Long Reads ◽

Mirna Sponges ◽

Rna Maturation

Circular RNAs (circRNAs) belong to a recently re-discovered species of RNA that emerge during RNA maturation through a process called back-splicing. A downstream 5’ splice site is linked to an upstream 3’ splice site to form a circular transcript instead of a canonical linear transcript. Recent advances in next-generation sequencing (NGS) have brought circRNAs back into the focus of many scientists. Since then, several studies reported that circRNAs are differentially expressed across tissue types and developmental stages, implying that they are actively regulated and not merely a by-product of splicing. Though functional studies have shown that some circRNAs could act as miRNA-sponges, the function of most circRNAs remains unknown. To expand our understanding of possible roles of circular RNAs, we propose a new pipeline that could fully characterizes candidate circRNA structure from RNAseq data – FUCHS: FUll CHaracterization of circular RNA using RNA- Sequencing. Currently, most computational prediction pipelines use back-spliced reads to identify circular RNAs. FUCHS extends this concept by considering all RNA-seq information from long reads (typically > 150 bp) to learn more about the exon coverage, the number of double break point fragments, the different circular isoforms arising from one host-gene, and the alternatively spliced exons within the same circRNA boundaries. This new knowledge will enable the user to carry out differential-motif enrichment and miRNA-seed analysis to determine potential regulators during circRNA biogenesis. FUCHS is an easy-to-use Python based pipeline that contributes a new aspect to the circRNA research. The pipeline is available as git repository: https://github.com/dieterich-lab/FUCHS

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