scholarly journals Comprehensive Characterization of Androgen-Responsive circRNAs in Prostate Cancer

Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1096
Author(s):  
Zhe Kong ◽  
Yali Lu ◽  
Xuechao Wan ◽  
Jun Luo ◽  
Dujian Li ◽  
...  

The androgen receptor (AR) signaling pathway plays an important role in the initiation and progression of prostate cancer. Circular RNAs (circRNAs), the novel noncoding RNAs without 5′ to 3′ polarity or 3′ poly (A), play an important role in multiple diseases. However, the potential roles of androgen-responsive circRNAs in prostate cancer remain unclear. In this study, we identified 3237 androgen-responsive circRNAs and 1954 androgen-responsive mRNAs after dihydrotestosterone (DHT) stimulation using microarray. Among them, the expression of 1296 androgen-responsive circRNAs was consistent with that of their parent genes, and we thought AR might regulate the expression of these circRNAs at the transcriptional level. In addition, 1941 circRNAs expression was not consistent with their parent genes, and we speculated that AR may regulate the expression of those circRNAs at the posttranscriptional level through affecting alternative splicing. Analyzing the androgen-responsive circRNAs regulated at the posttranscriptional level, we identified two key RNA binding proteins (RBPs), WTAP and TNRC6, using the circInteractome database, which may play important role in the biogenesis of androgen-responsive circRNAs. Furthermore, we explored the potential biological functions and predicted the molecular mechanisms of two dysregulated circRNAs (circNFIA and circZNF561) in prostate cancer. In this study, we revealed that circNFIA was upregulated in prostate cancer tissues and plasma samples from patients with prostate cancer; circNFIA may play an oncogenic role in prostate cancer. In contrast, circZNF561 was downregulated and may act as a tumor suppressor in prostate cancer. Our results suggest that androgen-responsive circRNAs might regulate the progression of prostate cancer and could be novel diagnostic biomarkers.

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Fei Long ◽  
Zhi Lin ◽  
Liang Li ◽  
Min Ma ◽  
Zhixing Lu ◽  
...  

AbstractColorectal cancer (CRC) is a common hereditary tumor that is often fatal. Its pathogenesis involves multiple genes, including circular RNAs (circRNAs). Notably, circRNAs constitute a new class of noncoding RNAs (ncRNAs) with a covalently closed loop structure and have been characterized as stable, conserved molecules that are abundantly expressed in tissue/development-specific patterns in eukaryotes. Based on accumulating evidence, circRNAs are aberrantly expressed in CRC tissues, cells, exosomes, and blood from patients with CRC. Moreover, numerous circRNAs have been identified as either oncogenes or tumor suppressors that mediate tumorigenesis, metastasis and chemoradiation resistance in CRC. Although the regulatory mechanisms of circRNA biogenesis and functions remain fairly elusive, interesting results have been obtained in studies investigating CRC. In particular, the expression of circRNAs in CRC is comprehensively modulated by multiple factors, such as splicing factors, transcription factors, specific enzymes and cis-acting elements. More importantly, circRNAs exert pivotal effects on CRC through various mechanisms, including acting as miRNA sponges or decoys, interacting with RNA binding proteins, and even translating functional peptides. Finally, circRNAs may serve as promising diagnostic and prognostic biomarkers and potential therapeutic targets in the clinical practice of CRC. In this review, we discuss the dysregulation, functions and clinical significance of circRNAs in CRC and further discuss the molecular mechanisms by which circRNAs exert their functions and how their expression is regulated. Based on this review, we hope to reveal the functions of circRNAs in the initiation and progression of cancer and highlight the future perspectives on strategies targeting circRNAs in cancer research.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Mandana Ameli-Mojarad ◽  
Melika Ameli-Mojarad ◽  
Mahrooyeh Hadizadeh ◽  
Chris Young ◽  
Hosna Babini ◽  
...  

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.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
S Greco ◽  
A Made' ◽  
M Longo ◽  
R Tikhomirov ◽  
S Castelvecchio ◽  
...  

Abstract Background Circular RNAs (circRNAs) are an emerging class of noncoding RNAs stemming from the splicing and circularization of pre-mRNAs exons. CircRNAs can regulate transcription and splicing, sequester microRNAs acting as “sponge” and inducing the respective targets, and bind to RNA binding proteins. Recently, they have been found deregulated in dilated cardiomyopathies (DCM), one of the cardiovascular diseases with the worst rate of morbidity and mortality, and whose molecular mechanisms are only partially known. Purpose Therein, we will evaluate in ischemic DCM patients the modulation of 17 circRNAs, 14 out of them obtained from literature data on DCM ischemic or not, while the other 3 were circRNAs not characterized in the heart previously. The study aims to identify circRNAs candidates for further functional characterization in DCM. In addition, as differential expression (DE) analysis is not easily performed for circRNAs in RNA-seq datasets, the validated circRNAs will be used to set up the most specific and sensitive bioinformatics pipeline for circRNA-DE analysis. Methods We designed divergent and convergent specific primers for 17 circRNAs and their host gene, respectively, and their amplification efficiency was measured by RT-qPCR. Transcripts expression was measured in left ventricle biopsies of 12 patients affected by non end-stage ischemic HF and of 12 matched controls. Results We identified cPVT1, cANKRD17, cBPTF as DE, and validated the modulation of 5 out of the 14 DCM-related circRNAs (cHIPK3, cALPK2, cPCMTD1, cNEBL, cSLC8A1), while cPDRM5, cTTN1 showed opposite modulation, which may be due to the specific disease condition. All of them were modulated differently from the respective host gene. CircRNA/miRNA interactions were predicted using Starbase 3.0. Next, mRNAs-targets of the identified miRNAs were predicted by mirDIP 4.1 and intersected with gene expression datasets of the same patients, previously obtained by microarray analysis. We found that cBPTF and cANKRD17 might sponge 12 and 2 miRNAs, respectively. Enrichment analysis of the relevant targets identified several important pathways implicated in DCM, such as MAPK, FoxO, EGFR, VEGF and Insulin/IGF pathways. In addition, deep RNA-Seq analysis that is currently ongoing and the validated circRNAs will be used to optimize the bioinformatics pipeline for circRNA DE analysis. Conclusions We identified a subset of circRNAs deregulated in ischemic HF potentially implicated in HF pathogenesis.


Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5113
Author(s):  
Agnieszka Rybak-Wolf ◽  
Mireya Plass

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder that heavily burdens healthcare systems worldwide. There is a significant requirement to understand the still unknown molecular mechanisms underlying AD. Current evidence shows that two of the major features of AD are transcriptome dysregulation and altered function of RNA binding proteins (RBPs), both of which lead to changes in the expression of different RNA species, including microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and messenger RNAs (mRNAs). In this review, we will conduct a comprehensive overview of how RNA dynamics are altered in AD and how this leads to the differential expression of both short and long RNA species. We will describe how RBP expression and function are altered in AD and how this impacts the expression of different RNA species. Furthermore, we will also show how changes in the abundance of specific RNA species are linked to the pathology of AD.


2019 ◽  
Vol 20 (16) ◽  
pp. 3926 ◽  
Author(s):  
Xing Zhao ◽  
Yujie Cai ◽  
Jianzhen Xu

CircRNAs are a class of noncoding RNA species with a circular configuration that is formed by either typical spliceosome-mediated or lariat-type splicing. The expression of circRNAs is usually abnormal in many cancers. Several circRNAs have been demonstrated to play important roles in carcinogenesis. In this review, we will first provide an introduction of circRNAs biogenesis, especially the regulation of circRNA by RNA-binding proteins, then we will focus on the recent findings of circRNA molecular mechanisms and functions in cancer development. Finally, some open questions are also discussed.


Author(s):  
Shiyu Mao ◽  
Wentao Zhang ◽  
Fuhan Yang ◽  
Yadong Guo ◽  
Hong Wang ◽  
...  

Abstract Background Circular RNAs (circRNAs) have been shown to play vital biological functions in various tumors, including prostate cancer (PCa). However, the roles of circRNAs in the metastasis of PCa remain unclear. In the present study, differentially expressed circRNAs associated with PCa metastasis were screened using high-throughput RNA sequencing, from which hsa_circ_0004296 was identified. Methods Quantitative real-time PCR (qRT-PCR) was used to detect the expression of circ_0004296 in PCa tissues and adjacent normal tissues as well as in blood and urine. Gain and loss of function experiments were performed to investigate the function of circ_0004296 in PCa. Bioinformatics analyses, RNA pull-down assay, and mass spectrometry were conducted to identify RNA-binding proteins. RNA immunoprecipitation and RNA and protein nuclear-cytoplasmic fractionation were performed to investigate the underlying mechanism. A xenograft mouse model was used to analyze the effect of circ_0004296 on PCa growth and metastasis in vivo. Results The expression of circ_0004296 was decreased in PCa tissues, blood, and urine, which was negatively associated with metastasis. Furthermore, gain and loss of function experiments in vitro and in vivo showed that circ_0004296 inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition of PCa cells. Mechanistically, circ_0004296 regulated host gene ETS1 expression at the post-transcriptional level. EIF4A3 was identified and confirmed as the downstream binding protein of circ_0004296. EIF4A3 expression was significantly upregulated in PCa tissues and associated with PCa metastasis. Silencing EIF4A3 suppressed PCa cell proliferation, migration, invasion, and EMT. Conclusions Circ_0004296 overexpression efficiently inhibited ETS1 mRNA nuclear export by promoting EIF4A3 retention in the nucleus, leading to the downregulation of ETS1 expression and suppression of PCa metastasis; thus, circ_0004296 might be a potential biomarker and therapeutic target for patients with PCa.


Cancers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1472 ◽  
Author(s):  
Peixin Dong ◽  
Daozhi Xu ◽  
Ying Xiong ◽  
Junming Yue ◽  
Kei Ihira ◽  
...  

Circular RNAs (circRNAs) are covalently closed, endogenous non-coding RNAs and certain circRNAs are linked to human tumors. Owing to their circular form, circRNAs are protected from degradation by exonucleases, and therefore, they are more stable than linear RNAs. Many circRNAs have been shown to sponge microRNAs, interact with RNA-binding proteins, regulate gene transcription, and be translated into proteins. Mounting evidence suggests that circRNAs are dysregulated in cancer tissues and can mediate various signaling pathways, thus affecting tumorigenesis, metastasis, and remodeling of the tumor microenvironment. First, we review the characteristics, biogenesis, and biological functions of circRNAs, and describe various mechanistic models of circRNAs. Then, we provide a systematic overview of the functional roles of circRNAs in gynecological cancers. Finally, we describe the potential future applications of circRNAs as biomarkers for prognostic stratification and as therapeutic targets in gynecological cancers. Although the function of most circRNAs remains elusive, some individual circRNAs have biologically relevant functions in cervical cancer, ovarian cancer, and endometrial cancer. Certain circRNAs have the potential to serve as biomarkers and therapeutic targets in gynecological cancers.


2019 ◽  
Vol 20 (24) ◽  
pp. 6249 ◽  
Author(s):  
Marta Correia de Sousa ◽  
Monika Gjorgjieva ◽  
Dobrochna Dolicka ◽  
Cyril Sobolewski ◽  
Michelangelo Foti

MicroRNAs (miRNAs) are small non-coding RNAs with the capability of modulating gene expression at the post-transcriptional level either by inhibiting messenger RNA (mRNA) translation or by promoting mRNA degradation. The outcome of a myriad of physiological processes and pathologies, including cancer, cardiovascular and metabolic diseases, relies highly on miRNAs. However, deciphering the precise roles of specific miRNAs in these pathophysiological contexts is challenging due to the high levels of complexity of their actions. Indeed, regulation of mRNA expression by miRNAs is frequently cell/organ specific; highly dependent on the stress and metabolic status of the organism; and often poorly correlated with miRNA expression levels. Such biological features of miRNAs suggest that various regulatory mechanisms control not only their expression, but also their activity and/or bioavailability. Several mechanisms have been described to modulate miRNA action, including genetic polymorphisms, methylation of miRNA promoters, asymmetric miRNA strand selection, interactions with RNA-binding proteins (RBPs) or other coding/non-coding RNAs. Moreover, nucleotide modifications (A-to-I or C-to-U) within the miRNA sequences at different stages of their maturation are also critical for their functionality. This regulatory mechanism called “RNA editing” involves specific enzymes of the adenosine/cytidine deaminase family, which trigger single nucleotide changes in primary miRNAs. These nucleotide modifications greatly influence a miRNA’s stability, maturation and activity by changing its specificity towards target mRNAs. Understanding how editing events impact miRNA’s ability to regulate stress responses in cells and organs, or the development of specific pathologies, e.g., metabolic diseases or cancer, should not only deepen our knowledge of molecular mechanisms underlying complex diseases, but can also facilitate the design of new therapeutic approaches based on miRNA targeting. Herein, we will discuss the current knowledge on miRNA editing and how this mechanism regulates miRNA biogenesis and activity.


2021 ◽  
Vol 22 (13) ◽  
pp. 6765
Author(s):  
Izabela Suster ◽  
Yue Feng

MicroRNAs (miRNAs) are small, non-coding RNAs that function as endogenous gene silencers. Soon after the discovery of miRNAs, a subset of brain-enriched and brain-specific miRNAs were identified and significant advancements were made in delineating miRNA function in brain development. However, understanding the molecular mechanisms that regulate miRNA biogenesis in normal and diseased brains has become a prevailing challenge. Besides transcriptional regulation of miRNA host genes, miRNA processing intermediates are subjected to multifaceted regulation by canonical miRNA processing enzymes, RNA binding proteins (RBPs) and epitranscriptomic modifications. Further still, miRNA activity can be regulated by the sponging activity of other non-coding RNA classes, namely circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs). Differential abundance of these factors in neuronal and glial lineages partly underlies the spatiotemporal expression and function of lineage-specific miRNAs. Here, we review the continuously evolving understanding of the regulation of neuronal and glial miRNA biogenesis at the transcriptional and posttranscriptional levels and the cooperativity of miRNA species in targeting key mRNAs to drive lineage-specific development. In addition, we review dysregulation of neuronal and glial miRNAs and the detrimental impacts which contribute to developmental brain disorders.


2021 ◽  
Author(s):  
Jing-yue Zhang ◽  
Yu Du ◽  
Li-ping Gong ◽  
Yi-ting Shao ◽  
Li-jie Pan ◽  
...  

Abstract Background: Emerging studies have showed that circular RNAs (circRNAs) are important regulators for tumorigenesis by modulating malignant behaviors of tumor cells. However, the functions of EBV-encoded circRNAs in EBV-associated gastric carcinoma (EBVaGC) remain poorly understood. Methods: The expression of ebv-circRPMS1 in EBVaGC tissues, xenografts and cell lines were analyzed by BaseScope, qRT-PCR and in situ hybridization (ISH). The effects of ebv-circRPMS1 on gastric carcinoma (GC) cell proliferation, apoptosis, migration and invasion were measured by CCK8, EdU, immunofluorescence (IF), FACS and Transwell assays. qRT-PCR, Western blotting, ChIP, RNA fluorescence in situ hybridization (RNA-FISH), luciferase reporter assays, mass spectrum, RNA immunoprecipitation (RIP), and pulldown assays were used to investigate the molecular mechanisms. Xenograft mouse model was also used to analyze the effect of ebv-circRPMS1 on GC growth and metastasis in vivo.Results: We demonstrated that ebv-circRPMS1 promoted the proliferation, migration, invasion and anti-apoptosis of EBVaGC cells. Mechanistically, ebv-circRPMS1 recruited the Sam68 complex to the promoter of METTL3 and enhanced its transcription. Moreover, overexpression of METTL3 induced transcriptional activation of downstream genes (such as SNAI1, ZMYM1 and SOCS2) via m6A modifications on their mRNAs, which were associated with tumor progression. Besides, RNA binding proteins (RBPs) such as QKI, DHX9 and ILF3, might involve in ebv-circRPMS1 biogenesis. In clinical EBVaGC samples, ebv-circRPMS1 was associated with distant metastasis and poor prognosis. Conclusion: These findings indicated that ebv-circRPMS1 contributed to EBVaGC progression through recruiting the Sam68 complex to activate METTL3 expression and its downstream targets. Ebv-circRPMS1, Sam68 and METTL3 may serve as therapeutic targets for EBVaGC.


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