Letter to the Editor: Issues of Circular RNAs as MicroRNA Sponges

Hepatology ◽  
2020 ◽  
Vol 72 (1) ◽  
pp. 365-365
Author(s):  
Yezhao Wang
Keyword(s):  
Circular Rnas ◽  
Letter To The Editor ◽  
Microrna Sponges

scholarly journals Advances in the Identification of Circular RNAs and Research Into circRNAs in Human Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Shihu Jiao ◽  
Song Wu ◽  
Shan Huang ◽  
Mingyang Liu ◽  
Bo Gao
Keyword(s):  
Neurological Disorders ◽  
Closed Loop ◽  
Significant Proportion ◽  
Human Diseases ◽  
Circular Rnas ◽  
The Status ◽  
Research Questions ◽  
Non Coding Rnas ◽  
Microrna Sponges

Circular RNAs (circRNAs) are a class of endogenous non-coding RNAs (ncRNAs) with a closed-loop structure that are mainly produced by variable processing of precursor mRNAs (pre-mRNAs). They are widely present in all eukaryotes and are very stable. Currently, circRNA studies have become a hotspot in RNA research. It has been reported that circRNAs constitute a significant proportion of transcript expression, and some are significantly more abundantly expressed than other transcripts. CircRNAs have regulatory roles in gene expression and critical biological functions in the development of organisms, such as acting as microRNA sponges or as endogenous RNAs and biomarkers. As such, they may have useful functions in the diagnosis and treatment of diseases. CircRNAs have been found to play an important role in the development of several diseases, including atherosclerosis, neurological disorders, diabetes, and cancer. In this paper, we review the status of circRNA research, describe circRNA-related databases and the identification of circRNAs, discuss the role of circRNAs in human diseases such as colon cancer, atherosclerosis, and gastric cancer, and identify remaining research questions related to circRNAs.

Circular RNAs as microRNA sponges: evidence and controversies

2021 ◽  
Author(s):  
Morten T. Jarlstad Olesen ◽  
Lasse S. Kristensen
Keyword(s):  
Gene Regulation ◽  
Target Genes ◽  
Research Field ◽  
Circular Rnas ◽  
Transcriptional Level ◽  
Additional Layer ◽  
Complex Process ◽  
Non Coding Rnas ◽  
New Research ◽  
Microrna Sponges

Abstract Gene expression in eukaryotic cells is a complex process encompassing several layers of regulation at the transcriptional and post-transcriptional levels. At the post-transcriptional level, microRNAs (miRs) are key regulatory molecules that function by binding directly to mRNAs. This generally leads to less efficient translation of the target mRNAs. More recently, an additional layer of gene regulation has been discovered, as other molecules, including circular RNAs (circRNAs), may bind to miRs and thereby function as sponges or decoys resulting in increased expression of the corresponding miR target genes. The circRNAs constitute a large class of mainly non-coding RNAs, which have been extensively studied in recent years, in particular in the cancer research field where many circRNAs have been proposed to function as miR sponges. Here, we briefly describe miR-mediated gene regulation and the extra layer of regulation that is imposed by the circRNAs. We describe techniques and methodologies that are commonly used to investigate potential miR sponging properties of circRNAs and discuss major pitfalls and controversies within this relatively new research field.

scholarly journals CircRNAs as potent biomarkers in ovarian cancer: a systematic scoping review

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Zahra Foruzandeh ◽  
Fatemeh Zeinali-Sehrig ◽  
Kazem Nejati ◽  
Dara Rahmanpour ◽  
Fariba Pashazadeh ◽  
...  
Keyword(s):  
Gene Expression ◽  
Ovarian Cancer ◽  
Chemotherapy Resistance ◽  
Developed Countries ◽  
Diagnostic Tools ◽  
Circular Rnas ◽  
Regulate Gene Expression ◽  
Microrna Sponges ◽  
Insight Into ◽  
Regulate Gene

AbstractMore powerful prognostic and diagnostic tools are urgently needed for identifying and treating ovarian cancer (OC), which is the most fatal malignancy in women in developed countries. Circular RNAs (circRNAs) are conservative and stable looped molecules that can regulate gene expression by competing with other endogenous microRNA sponges. This discovery provided new insight into novel methods for regulating genes that are involved in many disorders and cancers. This review focuses on the dysregulated expression of circRNAs as well as their diagnostic and prognostic values in OC. We found that studies have identified twenty-one downregulated circRNAs and fifty-seven upregulated ones. The results of these studies confirm that circRNAs might be potent biomarkers with diagnostic, prognostic and therapeutic target value for OC. We also consider the connection between circRNAs and OC cell proliferation, apoptosis, metastasis, and chemotherapy resistance and sensitivity.

scholarly journals circSLC30A7 Inhibits Hepatocellular Carcinoma Cell Proliferation via the miR-767-5p/FBXW7/NOTCH1 Axis

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xiaotian Yu ◽  
Yun Zhang ◽  
Chao Jiang ◽  
Feng Zhan ◽  
Zhenwei Shen ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Lines ◽  
Carcinoma Cell ◽  
Noncoding Rnas ◽  
Human Tumor ◽  
Circular Rnas ◽  
Biological Functions ◽  
Research Fields ◽  
Tumor Research ◽  
Microrna Sponges

Circular RNAs, noncoding RNAs, have attracted much attention in various human tumor research fields. They regulate the development of various human cancers via microRNA sponges. This study aimed to assess the molecular mechanism of circSLC30A7 in hepatocellular carcinoma (HCC). In our study, we identified that circSLC30A7 was significantly downregulated in HCC cell lines and tissues. Furthermore, gain and loss function experiments were conducted to elucidate the biological functions of circSLC30A7 in HCC cell lines. Mechanistically, circSLC30A7 sponged miR-767-5p, inhibiting the expression of its downstream protein, FBXW7. In summary, this study revealed that circSLC30A7 is an essential tumor suppressor that inhibits HCC tumorigenesis through the miR-767-5p/FBXW7/NOTCH1 axis. Taken together, circSLC30A7 reduces HCC malignancy and can be a biomarker for HCC management.

scholarly journals Circular RNAs as potential biomarkers and therapeutics for cardiovascular disease

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6831 ◽  
Author(s):  
Weitie Wang ◽  
Yong Wang ◽  
Hulin Piao ◽  
Bo Li ◽  
Maoxun Huang ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rnas ◽  
Covalent Bonds ◽  
Rna Molecules ◽  
Evolutionarily Conserved ◽  
Artery Disease ◽  
Covalently Linked ◽  
The Impact ◽  
Microrna Sponges

Circular RNAs (circRNAs) are genetic regulators that were earlier considered as “junk”. In contrast to linear RNAs, they have covalently linked ends with no polyadenylated tails. CircRNAs can act as RNA-binding proteins, sequestering agents, transcriptional regulators, as well as microRNA sponges. In addition, it is reported that some selected circRNAs are transformed into functional proteins. These RNA molecules always circularize through covalent bonds, and their presence has been demonstrated across species. They are usually abundant and stable as well as evolutionarily conserved in tissues (liver, lung, stomach), saliva, exosomes, and blood. Therefore, they have been proposed as the “next big thing” in molecular biomarkers for several diseases, particularly in cancer. Recently, circRNAs have been investigated in cardiovascular diseases (CVD) and reported to play important roles in heart failure, coronary artery disease, and myocardial infarction. Here, we review the recent literature and discuss the impact and the diagnostic and prognostic values of circRNAs in CVD.

Circular RNAs; powerful microRNA sponges to overcome Diabetic nephropathy

2021 ◽  
pp. 153618
Author(s):  
Alireza Mafi ◽  
Negar Yadegar ◽  
Marziyeh Salami ◽  
Raziyeh Salami ◽  
Omid Vakili ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Circular Rnas ◽  
Microrna Sponges

scholarly journals Exploring the regulatory roles of circular RNAs in Alzheimer’s disease

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Yuan Zhang ◽  
Yanfang Zhao ◽  
Ying Liu ◽  
Man Wang ◽  
Wanpeng Yu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neurological Disorders ◽  
Noncoding Rna ◽  
Epigenetic Modification ◽  
Research Progress ◽  
Circular Rnas ◽  
Protein Coding ◽  
Protein Coding Genes ◽  
Microrna Sponges

Abstract Circular RNAs (circRNAs) are a type of covalently closed, single-stranded circular noncoding RNA that can affect the expression of many protein-coding genes. Growing evidence has shown that circRNAs play critical roles in Alzheimer’s disease (AD) and may have therapeutic potentials for this disease. CircRNAs play regulatory roles in neural functions and neurological disorders through diverse mechanisms, including acting as microRNA sponges or interacting with proteins to regulate selective splicing or transcription, as well as through epigenetic modification. In this review, we discuss the biogenesis and functions of circRNAs and the research progress on circRNAs in AD to advance the understanding of how circRNAs contribute to this neurological disorder.

scholarly journals Circular RNAs: An emerging type of RNA in cancer

2017 ◽  
Vol 30 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Li-Dan Hou ◽  
Jing Zhang
Keyword(s):  
Rna Splicing ◽  
Protein Complexes ◽  
Predictive Biomarkers ◽  
Circular Rnas ◽  
Splice Donor ◽  
Associated Proteins ◽  
Non Coding Rnas ◽  
Rna Protein Complexes ◽  
Microrna Sponges ◽  
New Strategies

Circular RNAs (circRNAs), a novel type of widespread and diverse endogenous non-coding RNAs (ncRNAs), which are different from the linear RNAs, form a covalently closed continuous loop without 5’ or 3’ polarities. The majority of circRNAs are abundant, conserved and stable across different species, and exhibit tissue/developmental-stage-specific characteristics. They are generated primarily through a type of alternative RNA splicing called “back-splicing,” in which a downstream splice donor is joined to an upstream splice acceptor through splice skipping or direct splice. Recent studies have discovered circRNAs function as microRNA sponges, binding with RNA-associated proteins to form RNA–protein complexes and then regulating gene transcription and translation into polypeptides. Emerging evidence indicates that circRNAs play important roles in the regulation of the development and progression of multiple cancers by serving as potential diagnostic and predictive biomarkers involved in tumor growth and invasion and providing new strategies for cancer diagnosis and targeted therapy. In this review, we briefly delineate the diversity and characteristics of circRNAs and discuss the highlights of the biogenesis of circRNAs and their potential functions in tumor.

scholarly journals The Roles of CircRNAs in Bladder Cancer: Biomarkers, Tumorigenesis Drivers, and Therapeutic Targets

2021 ◽  
Vol 9 ◽  
Author(s):  
Fajuan Cheng ◽  
Bin Zheng ◽  
Shubin Si ◽  
Jianwei Wang ◽  
Guiting Zhao ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Circular Rnas ◽  
Therapeutic Approaches ◽  
Mesenchymal Transition ◽  
Diagnosis And Prognosis ◽  
Migratory Capacity ◽  
Non Coding Rnas ◽  
Endothelial Mesenchymal Transition ◽  
Microrna Sponges ◽  
Resistance To Chemotherapy

Bladder cancer (BCa) is the most prevalent malignancy of the urinary system. Circular RNAs (circRNAs), a novel subtype of non-coding RNAs, play a crucial role in physiological and developmental processes. CircRNAs mainly function as regulators of splicing process and transcription, microRNA sponges, and protein brackets. Recent advances in understanding the pathogenesis of BCa have led to the identification of an abundance of dysregulated circRNAs associated with BCa. These aberrantly expressed circRNAs eventually lead to abnormalities in biological, genetic, and epigenetic information. In this review, we introduce the potential of circRNAs as biomarkers for BCa diagnosis and prognosis. Notably, diverse mechanisms have been proposed for circRNAs driving carcinogenesis, including increasing cell proliferation, promoting invasive and migratory capacity, enhancing endothelial–mesenchymal transition, sustaining stemness, and enabling resistance to chemotherapy. Importantly, a full understanding of circRNA mechanisms is needed to mine promising therapeutic approaches for targeting BCa. In this paper, we present the latest advances in circRNAs and systemically summarize the characteristics and mechanisms of circRNAs in BCa, providing potential perspectives for BCa treatment.

scholarly journals Circular RNAs: A New Piece in the Colorectal Cancer Puzzle

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2464 ◽  
Author(s):  
Pinelopi I. Artemaki ◽  
Andreas Scorilas ◽  
Christos K. Kontos
Keyword(s):  
Colorectal Cancer ◽  
Colorectal Carcinogenesis ◽  
Circular Rnas ◽  
Aberrant Splicing ◽  
Aberrant Expression ◽  
Transcription Regulators ◽  
Molecular Base ◽  
By Products ◽  
Microrna Sponges

Colorectal cancer (CRC) is the third most fatal type of malignancy, worldwide. Despite the advances accomplished in the elucidation of its molecular base and the existing CRC biomarkers introduced in the clinical practice, additional research is required. Circular RNAs (circRNAs) constitute a new RNA type, formed by back-splicing of primary transcripts. They have been discovered during the 1970s but were characterized as by-products of aberrant splicing. However, the modern high-throughput approaches uncovered their widespread expression; therefore, several questions were raised regarding their potential biological roles. During the last years, great progress has been achieved in the elucidation of their functions: circRNAs can act as microRNA sponges, transcription regulators, and interfere with splicing, as well. Furthermore, they are heavily involved in various human pathological states, including cancer, and could serve as diagnostic and prognostic biomarkers in several diseases. Particularly in CRC, aberrant expression of circRNAs has been observed. More specifically, these molecules either inhibit or promote colorectal carcinogenesis by regulating different molecules and signaling pathways. The present review discusses the characteristics and functions of circRNA, prior to analyzing the multifaceted role of these molecules in CRC and their potential value as biomarkers and therapeutic targets.

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