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Ashley CN, Broni E, Miller WA. ADAR Family Proteins: A Structural Review. Curr Issues Mol Biol 2024; 46:3919-3945. [PMID: 38785511 PMCID: PMC11120146 DOI: 10.3390/cimb46050243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
This review aims to highlight the structures of ADAR proteins that have been crucial in the discernment of their functions and are relevant to future therapeutic development. ADAR proteins can correct or diversify genetic information, underscoring their pivotal contribution to protein diversity and the sophistication of neuronal networks. ADAR proteins have numerous functions in RNA editing independent roles and through the mechanisms of A-I RNA editing that continue to be revealed. Provided is a detailed examination of the ADAR family members-ADAR1, ADAR2, and ADAR3-each characterized by distinct isoforms that offer both structural diversity and functional variability, significantly affecting RNA editing mechanisms and exhibiting tissue-specific regulatory patterns, highlighting their shared features, such as double-stranded RNA binding domains (dsRBD) and a catalytic deaminase domain (CDD). Moreover, it explores ADARs' extensive roles in immunity, RNA interference, and disease modulation, demonstrating their ambivalent nature in both the advancement and inhibition of diseases. Through this comprehensive analysis, the review seeks to underline the potential of targeting ADAR proteins in therapeutic strategies, urging continued investigation into their biological mechanisms and health implications.
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Affiliation(s)
- Carolyn N. Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA; (C.N.A.); (E.B.)
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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Broni E, Ashley C, Velazquez M, Khan S, Striegel A, Sakyi PO, Peracha S, Bebla K, Sodhi M, Kwofie SK, Ademokunwa A, Miller WA. In Silico Discovery of Potential Inhibitors Targeting the RNA Binding Loop of ADAR2 and 5-HT2CR from Traditional Chinese Natural Compounds. Int J Mol Sci 2023; 24:12612. [PMID: 37628792 PMCID: PMC10454645 DOI: 10.3390/ijms241612612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/02/2023] [Accepted: 08/06/2023] [Indexed: 08/27/2023] Open
Abstract
Adenosine deaminase acting on RNA 2 (ADAR2) is an important enzyme involved in RNA editing processes, particularly in the conversion of adenosine to inosine in RNA molecules. Dysregulation of ADAR2 activity has been implicated in various diseases, including neurological disorders (including schizophrenia), inflammatory disorders, viral infections, and cancers. Therefore, targeting ADAR2 with small molecules presents a promising therapeutic strategy for modulating RNA editing and potentially treating associated pathologies. However, there are limited compounds that effectively inhibit ADAR2 reactions. This study therefore employed computational approaches to virtually screen natural compounds from the traditional Chinese medicine (TCM) library. The shortlisted compounds demonstrated a stronger binding affinity to the ADAR2 (<-9.5 kcal/mol) than the known inhibitor, 8-azanebularine (-6.8 kcal/mol). The topmost compounds were also observed to possess high binding affinity towards 5-HT2CR with binding energies ranging from -7.8 to -12.9 kcal/mol. Further subjecting the top ADAR2-ligand complexes to molecular dynamics simulations and molecular mechanics Poisson-Boltzmann surface area (MM/PBSA) calculations revealed that five potential hit compounds comprising ZINC000014637370, ZINC000085593577, ZINC000042890265, ZINC000039183320, and ZINC000101100339 had favorable binding free energies of -174.911, -137.369, -117.236, -67.023, and -64.913 kJ/mol, respectively, with the human ADAR2 protein. Residues Lys350, Cys377, Glu396, Cys451, Arg455, Ser486, Gln488, and Arg510 were also predicted to be crucial in ligand recognition and binding. This finding will provide valuable insights into the molecular interactions between ADAR2 and small molecules, aiding in the design of future ADAR2 inhibitors with potential therapeutic applications. The potential lead compounds were also profiled to have insignificant toxicities. A structural similarity search via DrugBank revealed that ZINC000039183320 and ZINC000014637370 were similar to naringin and naringenin, which are known adenosine deaminase (ADA) inhibitors. These potential novel ADAR2 inhibitors identified herein may be beneficial in treating several neurological disorders, cancers, viral infections, and inflammatory disorders caused by ADAR2 after experimental validation.
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Affiliation(s)
- Emmanuel Broni
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Carolyn Ashley
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Miriam Velazquez
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Sufia Khan
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Biology, Loyola University Chicago, Chicago, IL 60660, USA
| | - Andrew Striegel
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Chemical and Biochemistry, College of Science, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Patrick O. Sakyi
- Department of Chemistry, School of Physical and Mathematical Sciences, College of Basic and Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 56, Ghana
- Department of Chemical Sciences, School of Sciences, University of Energy and Natural Resources, Sunyani P.O. Box 214, Ghana
| | - Saqib Peracha
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Kristeen Bebla
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Monsheel Sodhi
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
| | - Samuel K. Kwofie
- Department of Biomedical Engineering, School of Engineering Sciences, College of Basic & Applied Sciences, University of Ghana, Legon, Accra P.O. Box LG 77, Ghana
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra P.O. Box LG 54, Ghana
| | - Adesanya Ademokunwa
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Cognitive and Behavioral Neuroscience, Loyola University Chicago, Chicago, IL 60660, USA
| | - Whelton A. Miller
- Department of Medicine, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
- Department of Molecular Pharmacology & Neuroscience, Loyola University Medical Center, Loyola University Chicago, Maywood, IL 60153, USA
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Hajji K, Sedmík J, Cherian A, Amoruso D, Keegan LP, O'Connell MA. ADAR2 enzymes: efficient site-specific RNA editors with gene therapy aspirations. RNA (NEW YORK, N.Y.) 2022; 28:1281-1297. [PMID: 35863867 PMCID: PMC9479739 DOI: 10.1261/rna.079266.122] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The adenosine deaminase acting on RNA (ADAR) enzymes are essential for neuronal function and innate immune control. ADAR1 RNA editing prevents aberrant activation of antiviral dsRNA sensors through editing of long, double-stranded RNAs (dsRNAs). In this review, we focus on the ADAR2 proteins involved in the efficient, highly site-specific RNA editing to recode open reading frames first discovered in the GRIA2 transcript encoding the key GLUA2 subunit of AMPA receptors; ADAR1 proteins also edit many of these sites. We summarize the history of ADAR2 protein research and give an up-to-date review of ADAR2 structural studies, human ADARBI (ADAR2) mutants causing severe infant seizures, and mouse disease models. Structural studies on ADARs and their RNA substrates facilitate current efforts to develop ADAR RNA editing gene therapy to edit disease-causing single nucleotide polymorphisms (SNPs). Artificial ADAR guide RNAs are being developed to retarget ADAR RNA editing to new target transcripts in order to correct SNP mutations in them at the RNA level. Site-specific RNA editing has been expanded to recode hundreds of sites in CNS transcripts in Drosophila and cephalopods. In Drosophila and C. elegans, ADAR RNA editing also suppresses responses to self dsRNA.
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Affiliation(s)
- Khadija Hajji
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | - Jiří Sedmík
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | - Anna Cherian
- CEITEC Masaryk University, Brno 62500, Czech Republic
| | | | - Liam P Keegan
- CEITEC Masaryk University, Brno 62500, Czech Republic
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Liu J, Hong S, Yang J, Zhang X, Wang Y, Wang H, Peng J, Hong L. Targeting purine metabolism in ovarian cancer. J Ovarian Res 2022; 15:93. [PMID: 35964092 PMCID: PMC9375293 DOI: 10.1186/s13048-022-01022-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 07/17/2022] [Indexed: 11/10/2022] Open
Abstract
Purine, an abundant substrate in organisms, is a critical raw material for cell proliferation and an important factor for immune regulation. The purine de novo pathway and salvage pathway are tightly regulated by multiple enzymes, and dysfunction in these enzymes leads to excessive cell proliferation and immune imbalance that result in tumor progression. Maintaining the homeostasis of purine pools is an effective way to control cell growth and tumor evolution, and exploiting purine metabolism to suppress tumors suggests interesting directions for future research. In this review, we describe the process of purine metabolism and summarize the role and potential therapeutic effects of the major purine-metabolizing enzymes in ovarian cancer, including CD39, CD73, adenosine deaminase, adenylate kinase, hypoxanthine guanine phosphoribosyltransferase, inosine monophosphate dehydrogenase, purine nucleoside phosphorylase, dihydrofolate reductase and 5,10-methylenetetrahydrofolate reductase. Purinergic signaling is also described. We then provide an overview of the application of purine antimetabolites, comprising 6-thioguanine, 6-mercaptopurine, methotrexate, fludarabine and clopidogrel. Finally, we discuss the current challenges and future opportunities for targeting purine metabolism in the treatment-relevant cellular mechanisms of ovarian cancer.
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Affiliation(s)
- Jingchun Liu
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Shasha Hong
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiang Yang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Xiaoyi Zhang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ying Wang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Haoyu Wang
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Jiaxin Peng
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Li Hong
- Department of Obstetrics and Gynecology, Renmin Hospital of Wuhan University, Wuhan, China.
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Raghava Kurup R, Oakes EK, Manning AC, Mukherjee P, Vadlamani P, Hundley HA. RNA binding by ADAR3 inhibits adenosine-to-inosine editing and promotes expression of immune response protein MAVS. J Biol Chem 2022; 298:102267. [PMID: 35850307 PMCID: PMC9418441 DOI: 10.1016/j.jbc.2022.102267] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 12/13/2022] Open
Abstract
Members of the ADAR family of double-stranded RNA–binding proteins regulate one of the most abundant RNA modifications in humans, the deamination of adenosine to inosine. Several transcriptome-wide studies have been carried out to identify RNA targets of the active deaminases ADAR1 and ADAR2. However, our understanding of ADAR3, the brain-specific deaminase-deficient ADAR family member, is limited to a few transcripts. In this study, we identified over 3300 transcripts bound by ADAR3 and observed that binding of ADAR3 correlated with reduced editing of over 400 sites in the glioblastoma transcriptome. We further investigated the impact of ADAR3 on gene regulation of the transcript that encodes MAVS, an essential protein in the innate immune response pathway. We observed reduced editing in the MAVS 3′ UTR in cells expressing increased ADAR3 or reduced ADAR1 suggesting ADAR3 acts as a negative regulator of ADAR1-mediated editing. While neither ADAR1 knockdown or ADAR3 overexpression affected MAVS mRNA expression, we demonstrate increased ADAR3 expression resulted in upregulation of MAVS protein expression. In addition, we created a novel genetic mutant of ADAR3 that exhibited enhanced RNA binding and MAVS upregulation compared with wildtype ADAR3. Interestingly, this ADAR3 mutant no longer repressed RNA editing, suggesting ADAR3 has a unique regulatory role beyond altering editing levels. Altogether, this study provides the first global view of ADAR3-bound RNAs in glioblastoma cells and identifies both a role for ADAR3 in repressing ADAR1-mediated editing and an RNA-binding dependent function of ADAR3 in regulating MAVS expression.
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Affiliation(s)
| | - Eimile K Oakes
- Department of Biology, Indiana University, Bloomington IN 47405, USA
| | - Aidan C Manning
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Priyanka Mukherjee
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Pranathi Vadlamani
- Medical Sciences Program, Indiana University School of Medicine-Bloomington, Bloomington IN 47405, USA
| | - Heather A Hundley
- Department of Biology, Indiana University, Bloomington IN 47405, USA.
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Ju X, Wang S, Yan P, Zhu C, Hu X, Dong J, Tan Z. Rapid Eye Movement Sleep Deprivation Combined With Fluoxetine Protects Against Depression-Induced Damage and Apoptosis in Rat Hippocampi via A1 Adenosine Receptor. Front Psychiatry 2021; 12:599399. [PMID: 34335318 PMCID: PMC8322534 DOI: 10.3389/fpsyt.2021.599399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 05/26/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Rapid eye movement sleep deprivation (REMSD) and fluoxetine affect depression, yet the detailed molecular mechanisms were not clear. Methods: Rat depression chronic unpredictable stress was constructed, and the body weight of rats was measured. The efficacy of REMSD and fluoxetine on the pleasure experience, exploration, and cognition of rats with depression was determined by the Sucrose preference test, the open field test, and Morris water task, respectively. The effects of REMSD and fluoxetine on depression-induced damage and apoptosis in rat hippocampi were detected using hematoxylin-eosin staining and terminal transferase-mediated biotin 2'-deoxyuridine, 5'-triphosphate nick end labeling. A1 adenosine receptor content was measured by immunohistochemistry. Relative expressions of the A1 adenosine receptor, proteins related to apoptosis (B Bcl-2-associated X protein; B-cell lymphoma 2), phosphoinositide 3-kinase, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific two were quantified by quantitative real-time polymerase chain reaction and Western blot as needed. Results: Depression decreased rat weight. REMSD combined with fluoxetine increased body weight, prompted rat behavior, alleviated depression-induced damage, attenuated apoptosis, and promoted A1 adenosine receptor level in rat hippocampi. Furthermore, the combined therapy upregulated expressions of A1 adenosine receptor, B-cell lymphoma 2, and phosphoinositide 3-kinase but downregulated those of B-cell lymphoma 2-associated X protein, P38 mitogen-activated protein kinase, cFos, and adenosine deaminase RNA specific 2 in the hippocampi of rats with depression. Conclusion:REMSD combined with fluoxetine protected rats against depression-induced damage and apoptosis in the hippocampus via the A1 adenosine receptor, providing a possible treatment strategy for depression.
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Affiliation(s)
- Xuan Ju
- Psychiatric Department, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Shengdong Wang
- Molecular Biology Laboratory, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Pan Yan
- Molecular Biology Laboratory, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Chunyan Zhu
- Psychiatric Department, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Xiwen Hu
- Psychiatric Department, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Jiezheng Dong
- Psychiatric Department, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhonglin Tan
- Psychiatric Department, Hangzhou Seventh People's Hospital, Mental Health Center of Zhejiang University School of Medicine, Hangzhou, China
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Abstract
RNA editing is a post-transcriptional process increasing transcript diversity, thereby regulating different biological processes. We recently observed that mutations resulting from RNA editing due to hydrolytic deamination of adenosine increase during the development of mesothelioma, a rare cancer linked to chronic exposure to asbestos. This review gathers information from the published literature and public data mining to explore several aspects of RNA editing and their possible implications for cancer growth and therapy. We address possible links between RNA editing and particular types of mesothelioma genetic and epigenetic alterations and discuss the relevance of an edited substrate in the context of current chemotherapy or immunotherapy.
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Affiliation(s)
- Ananya Hariharan
- Laboratory of Molecular Oncology, Department of Thoracic Surgery, Lungen- und Thoraxonkologie Zentrum, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Suna Sun
- Laboratory of Molecular Oncology, Department of Thoracic Surgery, Lungen- und Thoraxonkologie Zentrum, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Martin Wipplinger
- Laboratory of Molecular Oncology, Department of Thoracic Surgery, Lungen- und Thoraxonkologie Zentrum, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
| | - Emanuela Felley-Bosco
- Laboratory of Molecular Oncology, Department of Thoracic Surgery, Lungen- und Thoraxonkologie Zentrum, University Hospital Zurich, Sternwartstrasse 14, 8091 Zurich, Switzerland
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Liao Y, Jung SH, Kim T. A-to-I RNA editing as a tuner of noncoding RNAs in cancer. Cancer Lett 2020; 494:88-93. [PMID: 32822814 DOI: 10.1016/j.canlet.2020.08.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/11/2020] [Accepted: 08/07/2020] [Indexed: 12/26/2022]
Abstract
Recent advancement in RNA technology and computation biology shows the abundance and impact of RNA editing at the genome-wide level. Of RNA editing events, Adenosine-to-inosine (A-to-I) RNA editing is one of the most frequent types of RNA editing catalyzed by ADAR proteins. Indeed, A-to-I RNA editing occurs at the various coding and noncoding regions, triggering abnormal signaling pathways involved in cancer pathogenesis. Noncoding RNAs such as microRNA and long noncoding RNA have emerged as key regulators of pathways in cancer. The RNA editing including A-to-I editing is enriched in noncoding regions because of the abundance of noncoding RNAs accounting for 99% of total transcripts in the human genome. The effects of A-to-I editing in coding genes have been investigated and reported. However, those in noncoding RNAs have been less known in spite of the high frequency of editing events in noncoding regions. In this review, we will briefly discuss current findings and potential directions of A-to-I RNA editing research of noncoding RNAs and cancer. We will also introduce the concept of A-to-I editing, ADAR proteins, RNA editing technologies and databases.
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Affiliation(s)
- Yuanfan Liao
- Department of Anatomy, Histology and Developmental Biology, Base for International Science and Technology Cooperation, Carson Cancer Stem Cell Vaccines R&D Center, International Cancer Center, Shenzhen University, Health Science Center, Shenzhen, 518055, China
| | - Seung Ho Jung
- Applied Neuroscience, Warfighter Interface Division, 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson AFB, Dayton, OH, 45433, USA; ORISE, Oak Ridge, TN, 37830, USA.
| | - Taewan Kim
- Department of Anatomy, Histology and Developmental Biology, Base for International Science and Technology Cooperation, Carson Cancer Stem Cell Vaccines R&D Center, International Cancer Center, Shenzhen University, Health Science Center, Shenzhen, 518055, China; The Ohio State University Comprehensive Cancer Center, Columbus, OH, 43210, USA.
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Behroozi J, Shahbazi S, Bakhtiarizadeh MR, Mahmoodzadeh H. ADAR expression and copy number variation in patients with advanced gastric cancer. BMC Gastroenterol 2020; 20:152. [PMID: 32410589 PMCID: PMC7227226 DOI: 10.1186/s12876-020-01299-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 05/07/2020] [Indexed: 12/16/2022] Open
Abstract
Background Gastric cancer (GC) is a world health problem and it is the third leading cause of cancer deaths worldwide. The current practice for prognosis assessment in GC is based on radiological and pathological criteria and they may not result in an accurate prognosis. The aim of this study is to evaluate expression and copy number variation of the ADAR gene in advanced GC and clarify its correlation with survival and histopathological characteristics. Methods Forty two patients with stage III and IV GC were included in this study. ADAR gene expression and copy number variation were measured by real-time PCR and Quantitative multiplex fluorescent-PCR, respectively. Survival analysis performed based on the Kaplan–Meier method and Mantel–Cox test. Results ADAR mRNA was significantly overexpressed in the tumor tissues when compared to the adjacent normal tissues (p < 0.01). Also, ADAR expression level in stage IV was higher than stage III. 40% of patients showed amplification in ADAR gene and there was a positive correlation between ADAR copy number and expression. Increased ADAR expression was clearly correlated with poorer survival outcomes and Mantel–Cox test showed statistically significant differences between low and high expression groups (p < 0.0001). ADAR overexpression and amplification were significantly associated with metastasis, size and stage of tumor. Conclusions Together, our data indicate that amplification leads to over expression of ADAR and it could be used as a prognostic biomarker for disease progression, especially for the metastatic process in GC.
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Affiliation(s)
- Javad Behroozi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - Shirin Shahbazi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
| | | | - Habibollah Mahmoodzadeh
- Department of Surgical Oncology, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
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Piazzi M, Bavelloni A, Gallo A, Blalock WL. AKT-Dependent Phosphorylation of ADAR1p110 and ADAR2 Represents a New and Important Link Between Cell Signaling and RNA Editing. DNA Cell Biol 2020; 39:343-348. [PMID: 31999481 DOI: 10.1089/dna.2020.5351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
RNA editing is a process by which nascent RNA transcripts are covalently modified, thus enhancing the complexity of the transcriptome. The most common modifications are deaminations of adenosine to inosine at sites of complex RNA secondary structure, a process that is carried out by the adenosine deaminase acting on double-strand RNA (ADAR) family of RNA editases. Although much has been learned about the ADAR family members since their discovery, very little information on their post-transcriptional regulation has been reported. Similar to most proteins, the ADAR family members are post-translationally modified at multiple sites. We recently reported that members of the AKT kinase family directly phosphorylate ADAR1p110 and ADAR2 on a conserved threonine within the catalytic domain of the protein. Phosphorylation was observed to differentially inhibit the enzymatic activity of the ADAR proteins toward known RNA substrates. The direct downstream involvement of the AKT kinases in multiple major signaling pathways associated with cell survival, growth, glucose metabolism (insulin signaling), and differentiation is well established; thus, the AKT kinases represent a link between ADAR-dependent A-to-I editing and major signal transduction pathways that are necessary for cell maintenance and development.
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Affiliation(s)
- Manuela Piazzi
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza," Consiglio Nazionale delle Ricerca (IGM-CNR) Bologna, Italy.,IRCCS, Istituto Ortopedico Rizzoli, Bologna Italy
| | - Alberto Bavelloni
- Laboratory of Experimental Oncology, IRCCS, Istituto Ortopedico Rizzoli, Bologna, Italy
| | - Angela Gallo
- RNA Editing Laboratory, Dipartimento di Oncoematologia, IRCCS, Ospedale Pediatrica Bambino Gesù, Rome, Italy
| | - William L Blalock
- Istituto di Genetica Molecolare "Luigi Luca Cavalli-Sforza," Consiglio Nazionale delle Ricerca (IGM-CNR) Bologna, Italy.,IRCCS, Istituto Ortopedico Rizzoli, Bologna Italy
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