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Rehwinkel J, Mehdipour P. ADAR1: from basic mechanisms to inhibitors. Trends Cell Biol 2024:S0962-8924(24)00120-X. [PMID: 39030076 DOI: 10.1016/j.tcb.2024.06.006] [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: 02/13/2024] [Revised: 06/17/2024] [Accepted: 06/20/2024] [Indexed: 07/21/2024]
Abstract
Adenosine deaminase acting on RNA 1 (ADAR1) converts adenosine to inosine in double-stranded RNA (dsRNA) molecules, a process known as A-to-I editing. ADAR1 deficiency in humans and mice results in profound inflammatory diseases characterised by the spontaneous induction of innate immunity. In cells lacking ADAR1, unedited RNAs activate RNA sensors. These include melanoma differentiation-associated gene 5 (MDA5) that induces the expression of cytokines, particularly type I interferons (IFNs), protein kinase R (PKR), oligoadenylate synthase (OAS), and Z-DNA/RNA binding protein 1 (ZBP1). Immunogenic RNAs 'defused' by ADAR1 may include transcripts from repetitive elements and other long duplex RNAs. Here, we review these recent fundamental discoveries and discuss implications for human diseases. Some tumours depend on ADAR1 to escape immune surveillance, opening the possibility of unleashing anticancer therapies with ADAR1 inhibitors.
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Affiliation(s)
- Jan Rehwinkel
- Medical Research Council Translational Immune Discovery Unit, Medical Research Council Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DS, UK.
| | - Parinaz Mehdipour
- Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ, UK.
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Seo Y, Rhim J, Kim JH. RNA-binding proteins and exoribonucleases modulating miRNA in cancer: the enemy within. Exp Mol Med 2024; 56:1080-1106. [PMID: 38689093 PMCID: PMC11148060 DOI: 10.1038/s12276-024-01224-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 02/20/2024] [Accepted: 02/25/2024] [Indexed: 05/02/2024] Open
Abstract
Recent progress in the investigation of microRNA (miRNA) biogenesis and the miRNA processing machinery has revealed previously unknown roles of posttranscriptional regulation in gene expression. The molecular mechanistic interplay between miRNAs and their regulatory factors, RNA-binding proteins (RBPs) and exoribonucleases, has been revealed to play a critical role in tumorigenesis. Moreover, recent studies have shown that the proliferation of hepatocellular carcinoma (HCC)-causing hepatitis C virus (HCV) is also characterized by close crosstalk of a multitude of host RBPs and exoribonucleases with miR-122 and its RNA genome, suggesting the importance of the mechanistic interplay among these factors during the proliferation of HCV. This review primarily aims to comprehensively describe the well-established roles and discuss the recently discovered understanding of miRNA regulators, RBPs and exoribonucleases, in relation to various cancers and the proliferation of a representative cancer-causing RNA virus, HCV. These have also opened the door to the emerging potential for treating cancers as well as HCV infection by targeting miRNAs or their respective cellular modulators.
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Affiliation(s)
- Yoona Seo
- Cancer Molecular Biology Branch, Research Institute, National Cancer Center, Goyang, 10408, Korea
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, 10408, Korea
| | - Jiho Rhim
- Cancer Molecular Biology Branch, Research Institute, National Cancer Center, Goyang, 10408, Korea
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, 10408, Korea
| | - Jong Heon Kim
- Cancer Molecular Biology Branch, Research Institute, National Cancer Center, Goyang, 10408, Korea.
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, 10408, Korea.
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Hosseini A, Lindholm HT, Chen R, Mehdipour P, Marhon SA, Ishak CA, Moore PC, Classon M, Di Gioacchino A, Greenbaum B, De Carvalho DD. Retroelement decay by the exonuclease XRN1 is a viral mimicry dependency in cancer. Cell Rep 2024; 43:113684. [PMID: 38261511 DOI: 10.1016/j.celrep.2024.113684] [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: 07/06/2023] [Revised: 10/31/2023] [Accepted: 01/03/2024] [Indexed: 01/25/2024] Open
Abstract
Viral mimicry describes the immune response induced by endogenous stimuli such as double-stranded RNA (dsRNA) from endogenous retroelements. Activation of viral mimicry has the potential to kill cancer cells or augment anti-tumor immune responses. Here, we systematically identify mechanisms of viral mimicry adaptation associated with cancer cell dependencies. Among the top hits is the RNA decay protein XRN1 as an essential gene for the survival of a subset of cancer cell lines. XRN1 dependency is mediated by mitochondrial antiviral signaling protein and protein kinase R activation and is associated with higher levels of cytosolic dsRNA, higher levels of a subset of Alus capable of forming dsRNA, and higher interferon-stimulated gene expression, indicating that cells die due to induction of viral mimicry. Furthermore, dsRNA-inducing drugs such as 5-aza-2'-deoxycytidine and palbociclib can generate a synthetic dependency on XRN1 in cells initially resistant to XRN1 knockout. These results indicate that XRN1 is a promising target for future cancer therapeutics.
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Affiliation(s)
- Amir Hosseini
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Håvard T Lindholm
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Pathology, Oslo University Hospital-Rikshospitalet, 0372 Oslo, Norway
| | - Raymond Chen
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Parinaz Mehdipour
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Ludwig Institute for Cancer Research, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7DQ, UK
| | - Sajid A Marhon
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Charles A Ishak
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Paul C Moore
- Pfizer Centers for Therapeutic Innovation, South San Francisco, CA 94080, USA
| | - Marie Classon
- Pfizer Centers for Therapeutic Innovation, South San Francisco, CA 94080, USA
| | - Andrea Di Gioacchino
- Laboratoire de Physique de l'Ecole Normale Supérieure, PSL & CNRS UMR8063, Sorbonne Université, Université de Paris, Paris, France
| | - Benjamin Greenbaum
- Physiology, Biophysics & Systems Biology, Weill Cornell Medicine, Weill Cornell Medical College, New York, NY 10065, USA; Computational Oncology, Department of Epidemiology and Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Daniel D De Carvalho
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada.
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