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Draper J, Philipp J, Neeb Z, Thomas R, Katzman S, Salama S, Haussler D, Sanford JR. Isoform-specific translational control is evolutionarily conserved in primates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.21.537863. [PMID: 37131629 PMCID: PMC10153275 DOI: 10.1101/2023.04.21.537863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Alternative splicing (AS) alters messenger RNA (mRNA) coding capacity, localization, stability, and translation. Here we use comparative transcriptomics to identify cis- acting elements coupling AS to translational control (AS-TC). We sequenced total cytosolic and polyribosome-associated mRNA from human, chimpanzee, and orangutan induced pluripotent stem cells (iPSCs), revealing thousands of transcripts with splicing differences between subcellular fractions. We found both conserved and species-specific polyribosome association patterns for orthologous splicing events. Intriguingly, alternative exons with similar polyribosome profiles between species have stronger sequence conservation than exons with lineage-specific ribosome association. These data suggest that sequence variation underlies differences in the polyribosome association. Accordingly, single nucleotide substitutions in luciferase reporters designed to model exons with divergent polyribosome profiles are sufficient to regulate translational efficiency. We used position specific weight matrices to interpret exons with species-specific polyribosome association profiles, finding that polymorphic sites frequently alter recognition motifs for trans- acting RNA binding proteins. Together, our results show that AS can regulate translation by remodeling the cis- regulatory landscape of mRNA isoforms.
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2
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Harries LW. Dysregulated RNA processing and metabolism: a new hallmark of ageing and provocation for cellular senescence. FEBS J 2023; 290:1221-1234. [PMID: 35460337 DOI: 10.1111/febs.16462] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/28/2022] [Accepted: 04/21/2022] [Indexed: 12/23/2022]
Abstract
The human genome is capable of producing hundreds of thousands of different proteins and non-coding RNAs from <20 000 genes, in a co-ordinated and regulated fashion. This is achieved by a collection of phenomena known as mRNA processing and metabolism, and encompasses events in the life cycle of an RNA from synthesis to degradation. These factors are critical determinants of cellular adaptability and plasticity, which allows the cell to adjust its transcriptomic output in response to its internal and external environment. Evidence is building that dysfunctional RNA processing and metabolism may be a key contributor to the development of cellular senescence. Senescent cells by definition have exited cell cycle, but have gained functional features such as the secretion of the senescence-associated secretory phenotype (SASP), a known driver of chronic disease and perhaps even ageing itself. In this review, I will outline the impact of dysregulated mRNA processing and metabolism on senescence and ageing at the level of genes, cells and systems, and describe the mechanisms by which progressive deterioration in these processes may impact senescence and organismal ageing. Finally, I will present the evidence implicating this important process as a new hallmark of ageing, which could be harnessed in the future to develop new senotherapeutic interventions for chronic disease.
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3
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Lo A, McSharry M, Berger AH. Oncogenic KRAS alters splicing factor phosphorylation and alternative splicing in lung cancer. BMC Cancer 2022; 22:1315. [PMID: 36522653 PMCID: PMC9756471 DOI: 10.1186/s12885-022-10311-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 11/10/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Alternative RNA splicing is widely dysregulated in cancers including lung adenocarcinoma, where aberrant splicing events are frequently caused by somatic splice site mutations or somatic mutations of splicing factor genes. However, the majority of mis-splicing in cancers is unexplained by these known mechanisms. We hypothesize that the aberrant Ras signaling characteristic of lung cancers plays a role in promoting the alternative splicing observed in tumors. METHODS We recently performed transcriptome and proteome profiling of human lung epithelial cells ectopically expressing oncogenic KRAS and another cancer-associated Ras GTPase, RIT1. Unbiased analysis of phosphoproteome data identified altered splicing factor phosphorylation in KRAS-mutant cells, so we performed differential alternative splicing analysis using rMATS to identify significantly altered isoforms in lung epithelial cells. To determine whether these isoforms were uniquely regulated by KRAS, we performed a large-scale splicing screen in which we generated over 300 unique RNA sequencing profiles of isogenic A549 lung adenocarcinoma cells ectopically expressing 75 different wild-type or variant alleles across 28 genes implicated in lung cancer. RESULTS Mass spectrometry data showed widespread downregulation of splicing factor phosphorylation in lung epithelial cells expressing mutant KRAS compared to cells expressing wild-type KRAS. We observed alternative splicing in the same cells, with 2196 and 2416 skipped exon events in KRASG12V and KRASQ61H cells, respectively, 997 of which were shared (p < 0.001 by hypergeometric test). In the high-throughput splicing screen, mutant KRAS induced the greatest number of differential alternative splicing events, second only to the RNA binding protein RBM45 and its variant RBM45M126I. We identified ten high confidence cassette exon events across multiple KRAS variants and cell lines. These included differential splicing of the Myc Associated Zinc Finger (MAZ). As MAZ regulates expression of KRAS, this splice variant may be a mechanism for the cell to modulate wild-type KRAS levels in the presence of oncogenic KRAS. CONCLUSION Proteomic and transcriptomic profiling of lung epithelial cells uncovered splicing factor phosphorylation and mRNA splicing events regulated by oncogenic KRAS. These data suggest that in addition to widespread transcriptional changes, the Ras signaling pathway can promote post-transcriptional splicing changes that may contribute to oncogenic processes.
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Affiliation(s)
- April Lo
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Maria McSharry
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Alice H Berger
- Human Biology Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
- Department of Genome Sciences, University of Washington, Seattle, WA, USA.
- Herbold Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
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4
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Aubol BE, Adams JA. SRPK1 regulates RNA binding in a pre-spliceosomal complex using a catalytic bypass mechanism. FEBS J 2022; 289:7428-7445. [PMID: 35730996 DOI: 10.1111/febs.16560] [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: 02/15/2022] [Revised: 05/10/2022] [Accepted: 06/21/2022] [Indexed: 01/14/2023]
Abstract
Serine-arginine protein kinase 1 (SRPK1) phosphorylates serine-arginine (SR) proteins in the cytoplasm, directing them to the nucleus for splicing function. SRPK1 has also been detected in the nucleus but its function here is still not fully understood. We now demonstrate that nuclear SRPK1 can regulate U1-70K, a protein component of the uridine-rich 1 small nuclear ribonucleoprotein (U1 snRNP) that binds SR proteins and facilitates 5' splice-site selection in precursor mRNA. We found that SRPK1 uses a large, disordered domain to bind U1-70K, regulating the interaction of an exonic splicing enhancer (ESE) to the associated SR protein. Surprisingly, the catalytic activity of SRPK1 is not required for this phenomenon. Instead, SRPK1 associates directly with the N-terminus of U1-70K and alters the regulatory function of the distal C-terminus, modifying interactions between the U1-70K:SR protein complex and the ESE. Disruption of SRPK1 binding to this complex affects the alternative splicing of genes modulated by the C-terminus of U1-70K. Such findings suggest that, in addition to operating as a traditional serine-modifying catalyst, SRPK1 can also bypass this intrinsic activity to regulate RNA contacts in an early pre-spliceosomal complex.
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Affiliation(s)
- Brandon E Aubol
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA
| | - Joseph A Adams
- Department of Pharmacology, University of California San Diego, La Jolla, CA, USA
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5
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De Silva NIU, Fargason T, Zhang Z, Wang T, Zhang J. Inter-domain Flexibility of Human Ser/Arg-Rich Splicing Factor 1 Allows Variable Spacer Length in Cognate RNA’s Bipartite Motifs. Biochemistry 2022; 61:2922-2932. [DOI: 10.1021/acs.biochem.2c00565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Naiduwadura Ivon Upekala De Silva
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Talia Fargason
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Zihan Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Ting Wang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Jun Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
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6
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Shilo A, Pegoraro G, Misteli T. HiFENS: high-throughput FISH detection of endogenous pre-mRNA splicing isoforms. Nucleic Acids Res 2022; 50:e130. [PMID: 36243969 PMCID: PMC9825148 DOI: 10.1093/nar/gkac869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 09/01/2022] [Accepted: 09/27/2022] [Indexed: 01/29/2023] Open
Abstract
Splicing factors play an essential role in regulation of alternative pre-mRNA splicing. While much progress has been made in delineating the mechanisms of the splicing machinery, the identity of signal transduction pathways and upstream factors that regulate splicing factor activity is largely unknown. A major challenge in the discovery of upstream regulatory factors of pre-mRNA splicing is the scarcity of functional genomics screening methods to monitor splicing outcomes of endogenous genes. Here, we have developed HiFENS (high throughput FISH detection of endogenous splicing isoforms), a high-throughput imaging assay based on hybridization chain reaction (HCR) and used HiFENS to screen for cellular factors that regulate alternative splicing of endogenous genes. We demonstrate optimized detection with high specificity of endogenous splicing isoforms and multiplexing of probes for accurate detection of splicing outcomes with single cell resolution. As proof-of-principle, we perform an RNAi screen of 702 human kinases and identify potential candidate upstream splicing regulators of the FGFR2 gene. HiFENS should be a useful tool for the unbiased delineation of cellular pathways involved in alternative splicing regulation.
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Affiliation(s)
- Asaf Shilo
- Cell Biology of Genomes, Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Gianluca Pegoraro
- High-Throughput Imaging Facility (HiTIF), Center for Cancer Research (CCR), National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Tom Misteli
- To whom correspondence should be addressed. Tel: +1 240 670 6669; Fax: +1 240 670 6670;
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7
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Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the coronavirus disease 2019 (COVID-19) pandemic. Of particular interest for this topic are the signaling cascades that regulate cell survival and death, two opposite cell programs whose control is hijacked by viral infections. The AKT and the Unfolded Protein Response (UPR) pathways, which maintain cell homeostasis by regulating these two programs, have been shown to be deregulated during SARS-CoVs infection as well as in the development of cancer, one of the most important comorbidities in relation to COVID-19. Recent evidence revealed two way crosstalk mechanisms between the AKT and the UPR pathways, suggesting that they might constitute a unified homeostatic control system. Here, we review the role of the AKT and UPR pathways and their interaction in relation to SARS-CoV-2 infection as well as in tumor onset and progression. Feedback regulation between AKT and UPR pathways emerges as a master control mechanism of cell decision making in terms of survival or death and therefore represents a key potential target for developing treatments for both viral infection and cancer. In particular, drug repositioning, the investigation of existing drugs for new therapeutic purposes, could significantly reduce time and costs compared to de novo drug discovery.
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8
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Sun M, Jin Y, Zhang Y, Gregorich ZR, Ren J, Ge Y, Guo W. SR Protein Kinases Regulate the Splicing of Cardiomyopathy-Relevant Genes via Phosphorylation of the RSRSP Stretch in RBM20. Genes (Basel) 2022; 13:1526. [PMID: 36140694 PMCID: PMC9498672 DOI: 10.3390/genes13091526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/22/2022] [Accepted: 08/23/2022] [Indexed: 11/16/2022] Open
Abstract
(1) Background: RNA binding motif 20 (RBM20) regulates mRNA splicing specifically in muscle tissues. Missense mutations in the arginine/serine (RS) domain of RBM20 lead to abnormal gene splicing and have been linked to severe dilated cardiomyopathy (DCM) in human patients and animal models. Interestingly, many of the reported DCM-linked missense mutations in RBM20 are in a highly conserved RSRSP stretch within the RS domain. Recently, it was found that the two Ser residues within this stretch are constitutively phosphorylated, yet the identity of the kinase(s) responsible for phosphorylating these residues, as well as the function of RSRSP phosphorylation, remains unknown. (2) Methods: The ability of three known SR protein kinases (SRPK1, CLK1, and AKT2) to phosphorylate the RBM20 RSRSP stretch and regulate target gene splicing was evaluated by using both in vitro and in vivo approaches. (3) Results: We found that all three kinases phosphorylated S638 and S640 in the RSRSP stretch and regulated RBM20 target gene splicing. While SRPK1 and CLK1 were both capable of directly phosphorylating the RS domain in RBM20, whether AKT2-mediated control of the RS domain phosphorylation is direct or indirect could not be determined. (4) Conclusions: Our results indicate that SR protein kinases regulate the splicing of a cardiomyopathy-relevant gene by modulating phosphorylation of the RSRSP stretch in RBM20. These findings suggest that SR protein kinases may be potential targets for the treatment of RBM20 cardiomyopathy.
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Affiliation(s)
- Mingming Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY 82071, USA
| | - Yutong Jin
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Yanghai Zhang
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Zachery R Gregorich
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jun Ren
- Department of Cardiology, Shanghai Institute of Cardiovascular Diseases, Zhongshan Hospital Fudan University, Shanghai 200032, China
| | - Ying Ge
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Cell and Regenerative Biology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706, USA
- Human Proteomics Program, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Wei Guo
- Department of Animal and Dairy Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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9
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Dinesh NEH, Campeau PM, Reinhardt DP. Fibronectin isoforms in skeletal development and associated disorders. Am J Physiol Cell Physiol 2022; 323:C536-C549. [PMID: 35759430 DOI: 10.1152/ajpcell.00226.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The extracellular matrix is an intricate and essential network of proteins and non-proteinaceous components that provide a conducive microenvironment for cells to regulate cell function, differentiation, and survival. Fibronectin is one key component in the extracellular matrix that participates in determining cell fate and function crucial for normal vertebrate development. Fibronectin undergoes time dependent expression patterns during stem cell differentiation, providing a unique stem cell niche. Mutations in fibronectin have been recently identified to cause a rare form of skeletal dysplasia with scoliosis and abnormal growth plates. Even though fibronectin has been extensively analyzed in developmental processes, the functional role and importance of this protein and its various isoforms in skeletal development remains less understood. This review attempts to provide a concise and critical overview of the role of fibronectin isoforms in cartilage and bone physiology and associated pathologies. This will facilitate a better understanding of the possible mechanisms through which fibronectin exerts its regulatory role on cellular differentiation during skeletal development. The review discusses the consequences of mutations in fibronectin leading to corner fracture type spondylometaphyseal dysplasia and presents a new outlook towards matrix-mediated molecular pathways in relation to therapeutic and clinical relevance.
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Affiliation(s)
- Neha E H Dinesh
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada
| | | | - Dieter P Reinhardt
- Faculty of Medicine and Health Sciences, McGill University, Montreal, Canada.,Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, Canada
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10
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Ladewig E, Michelini F, Jhaveri K, Castel P, Carmona J, Fairchild L, Zuniga AG, Arruabarrena-Aristorena A, Cocco E, Blawski R, Kittane S, Zhang Y, Sallaku M, Baldino L, Hristidis V, Chandarlapaty S, Abdel-Wahab O, Leslie C, Scaltriti M, Toska E. The oncogenic PI3K-induced transcriptomic landscape reveals key functions in splicing and gene expression regulation. Cancer Res 2022; 82:2269-2280. [PMID: 35442400 DOI: 10.1158/0008-5472.can-22-0446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/25/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022]
Abstract
The PI3K pathway regulates proliferation, survival, and metabolism and is frequently activated across human cancers. A comprehensive elucidation of how this signaling pathway controls transcriptional and co-transcriptional processes could provide new insights into the key functions of PI3K signaling in cancer. Here, we undertook a transcriptomic approach to investigate genome-wide gene expression and transcription factor (TF) activity changes, as well as splicing and isoform usage dynamics, downstream of PI3K. These analyses uncovered widespread alternatively spliced (AS) isoforms linked to proliferation, metabolism, and splicing in PIK3CA mutant cells, which were reversed by inhibition of PI3Kα. Analysis of paired tumor biopsies from PIK3CA-mutated breast cancer patients undergoing treatment with PI3Kα inhibitors identified widespread splicing alterations that affect specific isoforms in common with the preclinical models, and these alterations, namely PTK2/FRNK and AFMID isoforms, were validated as functional drivers of cancer cell growth or migration. Mechanistically, isoform-specific splicing factors mediated PI3K-dependent RNA splicing. Treatment with splicing inhibitors rendered breast cancer cells more sensitive to the PI3Kα inhibitor alpelisib, resulting in greater growth inhibition than alpelisib alone. This study provides the first comprehensive analysis of widespread splicing alterations driven by oncogenic PI3K in breast cancer. The atlas of PI3K-mediated splicing programs establishes a key role for the PI3K pathway in regulating splicing, opening new avenues for exploiting PI3K signaling as a therapeutic vulnerability in breast cancer.
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Affiliation(s)
- Erik Ladewig
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | - Komal Jhaveri
- Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, NY, United States
| | - Pau Castel
- NYU Langone, New York, NY, United States
| | - Javier Carmona
- Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Lauren Fairchild
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Adler G Zuniga
- Johns Hopkins University School of Medicine, United States
| | | | | | - Ryan Blawski
- Johns Hopkins University School of Medicine, United States
| | - Srushti Kittane
- Johns Hopkins University Bloomberg School of Public Health, Baltimore, United States
| | - Yuhan Zhang
- Johns Hopkins University, Baltimore, United States
| | | | - Laura Baldino
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | | | - Omar Abdel-Wahab
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | - Christina Leslie
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | - Eneda Toska
- Johns Hopkins University, Baltimore, United States
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11
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Translational Regulation by hnRNP H/F Is Essential for the Proliferation and Survival of Glioblastoma. Cancers (Basel) 2022; 14:cancers14051283. [PMID: 35267591 PMCID: PMC8909726 DOI: 10.3390/cancers14051283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 02/21/2022] [Indexed: 02/05/2023] Open
Abstract
Deregulation of mRNA translation is a widespread characteristic of glioblastoma (GBM), aggressive malignant brain tumors that are resistant to conventional therapies. RNA-binding proteins (RBPs) play a critical role in translational regulation, yet the mechanisms and impact of these regulations on cancer development, progression and response to therapy remain to be fully understood. Here, we showed that hnRNP H/F RBPs are potent regulators of translation through several mechanisms that converge to modulate the expression and/or the activity of translation initiation factors. Among these, hnRNP H/F regulate the phosphorylation of eIF4E and its translational targets by controlling RNA splicing of the A-Raf kinase mRNA, which in turn modulates the MEK-ERK/MAPK signaling pathway. The underlying mechanism involves RNA G-quadruplex (RG4s), RNA structures whose modulation phenocopies hnRNP H/F translation regulation in GBM cells. Our results highlighted that hnRNP H/F are essential for key functional pathways regulating proliferation and survival of GBM, highlighting its targeting as a promising strategy for improving therapeutic outcomes.
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12
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Peng Q, Zhou Y, Oyang L, Wu N, Tang Y, Su M, Luo X, Wang Y, Sheng X, Ma J, Liao Q. Impacts and mechanisms of alternative mRNA splicing in cancer metabolism, immune response, and therapeutics. Mol Ther 2022; 30:1018-1035. [PMID: 34793975 PMCID: PMC8899522 DOI: 10.1016/j.ymthe.2021.11.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/29/2021] [Accepted: 11/11/2021] [Indexed: 02/08/2023] Open
Abstract
Alternative pre-mRNA splicing (AS) provides the potential to produce diversity at RNA and protein levels. Disruptions in the regulation of pre-mRNA splicing can lead to diseases. With the development of transcriptome and genome sequencing technology, increasing diseases have been identified to be associated with abnormal splicing of mRNAs. In tumors, abnormal alternative splicing frequently plays critical roles in cancer pathogenesis and may be considered as new biomarkers and therapeutic targets for cancer intervention. Metabolic abnormalities and immune disorders are important hallmarks of cancer. AS produces multiple different isoforms and diversifies protein expression, which is utilized by the immune and metabolic reprogramming systems to expand gene functions. The abnormal splicing events contributed to tumor progression, partially due to effects on immune response and metabolic reprogramming. Herein, we reviewed the vital role of alternative splicing in regulating cancer metabolism and immune response. We discussed how alternative splicing regulates metabolic reprogramming of cancer cells and antitumor immune response, and the possible strategies to targeting alternative splicing pathways or splicing-regulated metabolic pathway in the context of anticancer immunotherapy. Further, we highlighted the challenges and discuss the perspectives for RNA-based strategies for the treatment of cancer with abnormally alternative splicing isoforms.
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Affiliation(s)
- Qiu Peng
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China,Cancer Research Institute and School of Basic Medical Science, Central South University, Changsha, China
| | - Yujuan Zhou
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China,Hunan Key Laboratory of Translational Radiation Oncology, 283 Tongzipo Road, Changsha 410013, Hunan, China
| | - Linda Oyang
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Nayiyuan Wu
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Yanyan Tang
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Min Su
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Xia Luo
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Ying Wang
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Xiaowu Sheng
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China
| | - Jian Ma
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China; Cancer Research Institute and School of Basic Medical Science, Central South University, Changsha, China.
| | - Qianjin Liao
- Hunan Key Laboratory of Cancer Metabolism, Hunan Cancer Hospital and the Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, 410013 Hunan, China; Hunan Key Laboratory of Translational Radiation Oncology, 283 Tongzipo Road, Changsha 410013, Hunan, China.
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13
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Abuhashem A, Garg V, Hadjantonakis AK. RNA polymerase II pausing in development: orchestrating transcription. Open Biol 2022; 12:210220. [PMID: 34982944 PMCID: PMC8727152 DOI: 10.1098/rsob.210220] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The coordinated regulation of transcriptional networks underpins cellular identity and developmental progression. RNA polymerase II promoter-proximal pausing (Pol II pausing) is a prevalent mechanism by which cells can control and synchronize transcription. Pol II pausing regulates the productive elongation step of transcription at key genes downstream of a variety of signalling pathways, such as FGF and Nodal. Recent advances in our understanding of the Pol II pausing machinery and its role in transcription call for an assessment of these findings within the context of development. In this review, we discuss our current understanding of the molecular basis of Pol II pausing and its function during organismal development. By critically assessing the tools used to study this process we conclude that combining recently developed genomics approaches with refined perturbation systems has the potential to expand our understanding of Pol II pausing mechanistically and functionally in the context of development and beyond.
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Affiliation(s)
- Abderhman Abuhashem
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Weill Cornell/Rockefeller/Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY 10021, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
| | - Vidur Garg
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Anna-Katerina Hadjantonakis
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA,Biochemistry, Cell and Molecular Biology Graduate Program, Weill Cornell Medical College, New York, NY 10021, USA
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14
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Xiong J, Chen Y, Wang W, Sun J. Biological function and molecular mechanism of SRSF3 in cancer and beyond. Oncol Lett 2021; 23:21. [PMID: 34858525 PMCID: PMC8617561 DOI: 10.3892/ol.2021.13139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/07/2021] [Indexed: 12/15/2022] Open
Abstract
Serine/arginine-rich splicing factor 3 (SRSF3; also known as SRp20), an important member of the family of SRSFs, is abnormally expressed in tumors, resulting in aberrant splicing of hub genes, such as CD44, HER2, MDM4, Rac family small GTPase 1 and tumor protein p53. Under normal conditions, the splicing and expression of SRSF3 are strictly regulated. However, the splicing, expression and phosphorylation of SRSF3 are abnormal in tumors. SRSF3 plays important roles in the occurrence and development of tumors, including the promotion of tumorigenesis, cellular proliferation, the cell cycle and metastasis, as well as inhibition of cell senescence, apoptosis and autophagy. SRSF3-knockdown significantly inhibits the proliferation and metastatic characteristics of tumor cells. Therefore, SRSF3 may be suggested as a novel anti-tumor target. The other biological functions of SRSF3 and its regulatory mechanisms are also summarized in the current review.
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Affiliation(s)
- Jian Xiong
- Institute of Medical Biotechnology, Suzhou Vocational Health College, Suzhou, Jiangsu 215009, P.R. China
| | - Yinshuang Chen
- Center for Drug Metabolism and Pharmacokinetics, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Weipeng Wang
- Center for Drug Metabolism and Pharmacokinetics, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215123, P.R. China
| | - Jing Sun
- Institute of Medical Biotechnology, Suzhou Vocational Health College, Suzhou, Jiangsu 215009, P.R. China
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15
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Naro C, Bielli P, Sette C. Oncogenic dysregulation of pre-mRNA processing by protein kinases: challenges and therapeutic opportunities. FEBS J 2021; 288:6250-6272. [PMID: 34092037 PMCID: PMC8596628 DOI: 10.1111/febs.16057] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/13/2021] [Accepted: 06/04/2021] [Indexed: 12/12/2022]
Abstract
Alternative splicing and polyadenylation represent two major steps in pre-mRNA-processing, which ensure proper gene expression and diversification of human transcriptomes. Deregulation of these processes contributes to oncogenic programmes involved in the onset, progression and evolution of human cancers, which often result in the acquisition of resistance to existing therapies. On the other hand, cancer cells frequently increase their transcriptional rate and develop a transcriptional addiction, which imposes a high stress on the pre-mRNA-processing machinery and establishes a therapeutically exploitable vulnerability. A prominent role in fine-tuning pre-mRNA-processing mechanisms is played by three main families of protein kinases: serine arginine protein kinase (SRPK), CDC-like kinase (CLK) and cyclin-dependent kinase (CDK). These kinases phosphorylate the RNA polymerase, splicing factors and regulatory proteins involved in cleavage and polyadenylation of the nascent transcripts. The activity of SRPKs, CLKs and CDKs can be altered in cancer cells, and their inhibition was shown to exert anticancer effects. In this review, we describe key findings that have been reported on these topics and discuss challenges and opportunities of developing therapeutic approaches targeting splicing factor kinases.
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Affiliation(s)
- Chiara Naro
- Department of NeuroscienceSection of Human AnatomyCatholic University of the Sacred HeartRomeItaly
- Fondazione Policlinico Universitario A. GemelliIRCCSRomeItaly
| | - Pamela Bielli
- Department of Biomedicine and PreventionUniversity of Rome Tor VergataItaly
- Fondazione Santa LuciaIRCCSRomeItaly
| | - Claudio Sette
- Department of NeuroscienceSection of Human AnatomyCatholic University of the Sacred HeartRomeItaly
- Fondazione Santa LuciaIRCCSRomeItaly
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16
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Ruta V, Pagliarini V, Sette C. Coordination of RNA Processing Regulation by Signal Transduction Pathways. Biomolecules 2021; 11:biom11101475. [PMID: 34680108 PMCID: PMC8533259 DOI: 10.3390/biom11101475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 02/06/2023] Open
Abstract
Signal transduction pathways transmit the information received from external and internal cues and generate a response that allows the cell to adapt to changes in the surrounding environment. Signaling pathways trigger rapid responses by changing the activity or localization of existing molecules, as well as long-term responses that require the activation of gene expression programs. All steps involved in the regulation of gene expression, from transcription to processing and utilization of new transcripts, are modulated by multiple signal transduction pathways. This review provides a broad overview of the post-translational regulation of factors involved in RNA processing events by signal transduction pathways, with particular focus on the regulation of pre-mRNA splicing, cleavage and polyadenylation. The effects of several post-translational modifications (i.e., sumoylation, ubiquitination, methylation, acetylation and phosphorylation) on the expression, subcellular localization, stability and affinity for RNA and protein partners of many RNA-binding proteins are highlighted. Moreover, examples of how some of the most common signal transduction pathways can modulate biological processes through changes in RNA processing regulation are illustrated. Lastly, we discuss challenges and opportunities of therapeutic approaches that correct RNA processing defects and target signaling molecules.
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Affiliation(s)
- Veronica Ruta
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Laboratory of Neuroembryology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
- Correspondence:
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17
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Hensel JA, Heineman BD, Kimble AL, Jellison ER, Reese B, Murphy PA. Identification of splice regulators of fibronectin-EIIIA and EIIIB by direct measurement of exon usage in a flow-cytometry based CRISPR screen. Sci Rep 2021; 11:19835. [PMID: 34615942 PMCID: PMC8494765 DOI: 10.1038/s41598-021-99079-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/14/2021] [Indexed: 12/26/2022] Open
Abstract
The extracellular matrix protein fibronectin (FN) is alternatively spliced in a variety of inflammatory conditions, resulting in increased inclusion of alternative exons EIIIA and EIIIB. Inclusion of these exons affects fibril formation, fibrosis, and inflammation. To define upstream regulators of alternative splicing in FN, we have developed an in vitro flow-cytometry based assay, using RNA-binding probes to determine alternative exon inclusion level in aortic endothelial cells. This approach allows us to detect exon inclusion in the primary transcripts themselves, rather than in surrogate splicing reporters. We validated this assay in cells with and without FN-EIIIA and -EIIIB expression. In a small-scale CRISPR KO screen of candidate regulatory splice factors, we successfully detected known regulators of EIIIA and EIIIB splicing, and detected several novel regulators. Finally, we show the potential in this approach to broadly interrogate upstream signaling pathways in aortic endothelial cells with a genome-wide CRISPR-KO screen, implicating the TNFalpha and RIG-I-like signaling pathways and genes involved in the regulation of fibrotic responses. Thus, we provide a novel means to screen the regulation of splicing of endogenous transcripts, and predict novel pathways in the regulation of FN-EIIIA inclusion.
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Affiliation(s)
| | | | - Amy L Kimble
- Center for Vascular Biology, UCONN Health, Farmington, CT, USA
| | | | - Bo Reese
- Institute for Systems Genomics - Center for Genome Innovation, UCONN, Storrs, CT, USA
| | - Patrick A Murphy
- Center for Vascular Biology, UCONN Health, Farmington, CT, USA. .,Center for Vascular Biology & Calhoun Cardiology Center, University of Connecticut Medical School, 263 Farmington Avenue, Farmingon, CT, 06030, USA.
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18
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Dennison BJC, Larson ED, Fu R, Mo J, Fantauzzo KA. Srsf3 mediates alternative RNA splicing downstream of PDGFRα signaling in the facial mesenchyme. Development 2021; 148:269256. [PMID: 34184034 DOI: 10.1242/dev.199448] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 06/10/2021] [Indexed: 12/13/2022]
Abstract
Signaling through the platelet-derived growth factor receptor alpha (PDGFRα) is crucial for mammalian craniofacial development, although the mechanisms by which the activity of downstream intracellular effectors is regulated to mediate gene expression changes have not been defined. We find that the RNA-binding protein Srsf3 is phosphorylated at Akt consensus sites downstream of PI3K-mediated PDGFRα signaling in mouse palatal mesenchyme cells, leading to its nuclear translocation. We further demonstrate that ablation of Srsf3 in the mouse neural crest lineage leads to facial clefting due to defective cranial neural crest cell proliferation and survival. Finally, we show that Srsf3 regulates the alternative RNA splicing of transcripts encoding protein kinases in the mouse facial process mesenchyme to regulate PDGFRα-dependent intracellular signaling. Collectively, our findings reveal that alternative RNA splicing is an important mechanism of gene expression regulation downstream of PI3K/Akt-mediated PDGFRα signaling in the facial mesenchyme and identify Srsf3 as a critical regulator of craniofacial development.
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Affiliation(s)
- Brenna J C Dennison
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Eric D Larson
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Rui Fu
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Julia Mo
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Katherine A Fantauzzo
- Department of Craniofacial Biology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA.,RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
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19
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Yang H, Beutler B, Zhang D. Emerging roles of spliceosome in cancer and immunity. Protein Cell 2021; 13:559-579. [PMID: 34196950 PMCID: PMC9232692 DOI: 10.1007/s13238-021-00856-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/08/2021] [Indexed: 12/19/2022] Open
Abstract
Precursor messenger RNA (pre-mRNA) splicing is catalyzed by an intricate ribonucleoprotein complex called the spliceosome. Although the spliceosome is considered to be general cell “housekeeping” machinery, mutations in core components of the spliceosome frequently correlate with cell- or tissue-specific phenotypes and diseases. In this review, we expound the links between spliceosome mutations, aberrant splicing, and human cancers. Remarkably, spliceosome-targeted therapies (STTs) have become efficient anti-cancer strategies for cancer patients with splicing defects. We also highlight the links between spliceosome and immune signaling. Recent studies have shown that some spliceosome gene mutations can result in immune dysregulation and notable phenotypes due to mis-splicing of immune-related genes. Furthermore, several core spliceosome components harbor splicing-independent immune functions within the cell, expanding the functional repertoire of these diverse proteins.
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Affiliation(s)
- Hui Yang
- Department of Neurosurgery, Huashan Hospital, Shanghai Key laboratory of Brain Function Restoration and Neural Regeneration, MOE Frontiers Center for Brain Science, Institute for Translational Brain Research, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Bruce Beutler
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Duanwu Zhang
- Children's Hospital of Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism, Ministry of Science and Technology, Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, China.
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20
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Li Q, Zeng C, Liu H, Yung KWY, Chen C, Xie Q, Zhang Y, Wan SWC, Mak BSW, Xia J, Xiong S, Ngo JCK. Protein-Protein Interaction Inhibitor of SRPKs Alters the Splicing Isoforms of VEGF and Inhibits Angiogenesis. iScience 2021; 24:102423. [PMID: 33997701 PMCID: PMC8102418 DOI: 10.1016/j.isci.2021.102423] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 03/13/2021] [Accepted: 04/09/2021] [Indexed: 12/14/2022] Open
Abstract
Serine-arginine (SR) protein kinases (SRPKs) regulate the functions of the SR-rich splicing factors by phosphorylating multiple serines within their C-terminal arginine-serine-rich domains. Dysregulation of these phosphorylation events has been implicated in many diseases, suggesting SRPKs are potential therapeutic targets. In particular, aberrant SRPK1 expression alters the balances of proangiogenic (VEGF165) and antiangiogenic (VEGF165b) splicing isoforms of the key angiogenesis factor, vascular endothelial growth factor (VEGF), through the phosphorylation of prototypic SR protein SRSF1. Here, we report a protein-protein interaction (PPI) inhibitor of SRPKs, docking blocker of SRPK1 (DBS1), that specifically blocks a conserved substrate docking groove unique to SRPKs. DBS1 is a cell-permeable inhibitor that effectively inhibits the binding and phosphorylation of SRSF1 and subsequently switches VEGF splicing from the proangiogenic to the antiangiogenic isoform. Our findings thus provide a new direction for the development of SRPK inhibitors through targeting a unique PPI site to combat angiogenic diseases.
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Affiliation(s)
- Qingyun Li
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Hong Kong Branch of National Engineering Research Center of Genetic Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Chuyue Zeng
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Haizhen Liu
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Kristen Wing Yu Yung
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Chun Chen
- Department of Cellular Biology, Jinan University, Guangzhou, China
| | - Qiuling Xie
- Department of Cellular Biology, Jinan University, Guangzhou, China
| | - Yu Zhang
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Stephanie Winn Chee Wan
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Bertha Sze Wing Mak
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Jiang Xia
- Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Sheng Xiong
- Department of Cellular Biology, Jinan University, Guangzhou, China
- Hong Kong Branch of National Engineering Research Center of Genetic Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
| | - Jacky Chi Ki Ngo
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Hong Kong Branch of National Engineering Research Center of Genetic Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
- Center for Soybean Research of the State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China
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21
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Abstract
PURPOSE OF REVIEW This review aims to give an update on recent findings related to the cardiac splicing factor RNA-binding motif protein 20 (RBM20) and RBM20 cardiomyopathy, a form of dilated cardiomyopathy caused by mutations in RBM20. RECENT FINDINGS While most research on RBM20 splicing targets has focused on titin (TTN), multiple studies over the last years have shown that other splicing targets of RBM20 including Ca2+/calmodulin-dependent kinase IIδ (CAMK2D) might be critically involved in the development of RBM20 cardiomyopathy. In this regard, loss of RBM20 causes an abnormal intracellular calcium handling, which may relate to the arrhythmogenic presentation of RBM20 cardiomyopathy. In addition, RBM20 presents clinically in a highly gender-specific manner, with male patients suffering from an earlier disease onset and a more severe disease progression. Further research on RBM20, and treatment of RBM20 cardiomyopathy, will need to consider both the multitude and relative contribution of the different splicing targets and related pathways, as well as gender differences.
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22
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SRSF1 inhibits autophagy through regulating Bcl-x splicing and interacting with PIK3C3 in lung cancer. Signal Transduct Target Ther 2021; 6:108. [PMID: 33664238 PMCID: PMC7933324 DOI: 10.1038/s41392-021-00495-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 12/10/2020] [Accepted: 01/18/2021] [Indexed: 12/26/2022] Open
Abstract
Alternative splicing is a critical process to generate protein diversity. However, whether and how alternative splicing regulates autophagy remains largely elusive. Here we systematically identify the splicing factor SRSF1 as an autophagy suppressor. Specifically, SRSF1 inhibits autophagosome formation by reducing the accumulation of LC3-II and numbers of autophagosomes in different cell lines. Mechanistically, SRSF1 promotes the splicing of the long isoform of Bcl-x that interacts with Beclin1, thereby dissociating the Beclin1-PIK3C3 complex. In addition, SRSF1 also directly interacts with PIK3C3 to disrupt the interaction between Beclin1 and PIK3C3. Consequently, the decrease of SRSF1 stabilizes the Beclin1 and PIK3C3 complex and activates autophagy. Interestingly, SRSF1 can be degraded by starvation- and oxidative stresses-induced autophagy through interacting with LC3-II, whereas reduced SRSF1 further promotes autophagy. This positive feedback is critical to inhibiting Gefitinib-resistant cancer cell progression both in vitro and in vivo. Consistently, the expression level of SRSF1 is inversely correlated to LC3 level in clinical cancer samples. Our study not only provides mechanistic insights of alternative splicing in autophagy regulation but also discovers a new regulatory role of SRSF1 in tumorigenesis, thereby offering a novel avenue for potential cancer therapeutics.
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23
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Hekman RM, Hume AJ, Goel RK, Abo KM, Huang J, Blum BC, Werder RB, Suder EL, Paul I, Phanse S, Youssef A, Alysandratos KD, Padhorny D, Ojha S, Mora-Martin A, Kretov D, Ash PEA, Verma M, Zhao J, Patten JJ, Villacorta-Martin C, Bolzan D, Perea-Resa C, Bullitt E, Hinds A, Tilston-Lunel A, Varelas X, Farhangmehr S, Braunschweig U, Kwan JH, McComb M, Basu A, Saeed M, Perissi V, Burks EJ, Layne MD, Connor JH, Davey R, Cheng JX, Wolozin BL, Blencowe BJ, Wuchty S, Lyons SM, Kozakov D, Cifuentes D, Blower M, Kotton DN, Wilson AA, Mühlberger E, Emili A. Actionable Cytopathogenic Host Responses of Human Alveolar Type 2 Cells to SARS-CoV-2. Mol Cell 2020; 80:1104-1122.e9. [PMID: 33259812 PMCID: PMC7674017 DOI: 10.1016/j.molcel.2020.11.028] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/16/2020] [Accepted: 11/11/2020] [Indexed: 12/11/2022]
Abstract
Human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causative pathogen of the COVID-19 pandemic, exerts a massive health and socioeconomic crisis. The virus infects alveolar epithelial type 2 cells (AT2s), leading to lung injury and impaired gas exchange, but the mechanisms driving infection and pathology are unclear. We performed a quantitative phosphoproteomic survey of induced pluripotent stem cell-derived AT2s (iAT2s) infected with SARS-CoV-2 at air-liquid interface (ALI). Time course analysis revealed rapid remodeling of diverse host systems, including signaling, RNA processing, translation, metabolism, nuclear integrity, protein trafficking, and cytoskeletal-microtubule organization, leading to cell cycle arrest, genotoxic stress, and innate immunity. Comparison to analogous data from transformed cell lines revealed respiratory-specific processes hijacked by SARS-CoV-2, highlighting potential novel therapeutic avenues that were validated by a high hit rate in a targeted small molecule screen in our iAT2 ALI system.
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Affiliation(s)
- Ryan M Hekman
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Adam J Hume
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Raghuveera Kumar Goel
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Kristine M Abo
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Jessie Huang
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Benjamin C Blum
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Rhiannon B Werder
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Ellen L Suder
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Indranil Paul
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Sadhna Phanse
- Center for Network Systems Biology, Boston University, Boston, MA, USA
| | - Ahmed Youssef
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; Bioinformatics Program, Boston University, Boston, MA, USA
| | - Konstantinos D Alysandratos
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Dzmitry Padhorny
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, USA
| | - Sandeep Ojha
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | | | - Dmitry Kretov
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Peter E A Ash
- Department of Pharmacology, Boston University School of Medicine, Boston, MA, USA
| | - Mamta Verma
- Department of Pharmacology, Boston University School of Medicine, Boston, MA, USA
| | - Jian Zhao
- Department of Electrical and Computer Engineering, Boston University, Boston, MA, USA
| | - J J Patten
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Carlos Villacorta-Martin
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA
| | - Dante Bolzan
- Department of Computer Science, University of Miami, Miami, FL, USA
| | - Carlos Perea-Resa
- Department of Molecular Biology, Harvard Medical School, Boston, MA, USA
| | - Esther Bullitt
- Department of Physiology and Biophysics, Boston University, Boston, MA, USA
| | - Anne Hinds
- The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Andrew Tilston-Lunel
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Xaralabos Varelas
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Shaghayegh Farhangmehr
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | | | - Julian H Kwan
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Mark McComb
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; Center for Biomedical Mass Spectrometry, Boston University School of Medicine, Boston, MA, USA
| | - Avik Basu
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Mohsan Saeed
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Valentina Perissi
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Eric J Burks
- Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Matthew D Layne
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - John H Connor
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Robert Davey
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA
| | - Ji-Xin Cheng
- Department of Biomedical Engineering, Boston University, Boston, MA, USA
| | - Benjamin L Wolozin
- Department of Pharmacology, Boston University School of Medicine, Boston, MA, USA
| | - Benjamin J Blencowe
- Donnelly Centre, University of Toronto, Toronto, ON, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Stefan Wuchty
- Department of Computer Science, University of Miami, Miami, FL, USA; Department of Biology, University of Miami, Miami, FL, USA; Miami Institute of Data Science and Computing, Miami, FL, USA
| | - Shawn M Lyons
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Dima Kozakov
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA; Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, NY, USA
| | - Daniel Cifuentes
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA
| | - Michael Blower
- Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; Department of Molecular Biology, Harvard Medical School, Boston, MA, USA
| | - Darrell N Kotton
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
| | - Andrew A Wilson
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA, USA; The Pulmonary Center, Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
| | - Elke Mühlberger
- Department of Microbiology, Boston University School of Medicine, Boston, MA, USA; National Emerging Infectious Diseases Laboratories, Boston University, Boston, MA, USA.
| | - Andrew Emili
- Center for Network Systems Biology, Boston University, Boston, MA, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA, USA; Department of Biology, Boston University, Boston, MA, USA.
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24
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Bessa C, Matos P, Jordan P, Gonçalves V. Alternative Splicing: Expanding the Landscape of Cancer Biomarkers and Therapeutics. Int J Mol Sci 2020; 21:ijms21239032. [PMID: 33261131 PMCID: PMC7729450 DOI: 10.3390/ijms21239032] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 11/24/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023] Open
Abstract
Alternative splicing (AS) is a critical post-transcriptional regulatory mechanism used by more than 95% of transcribed human genes and responsible for structural transcript variation and proteome diversity. In the past decade, genome-wide transcriptome sequencing has revealed that AS is tightly regulated in a tissue- and developmental stage-specific manner, and also frequently dysregulated in multiple human cancer types. It is currently recognized that splicing defects, including genetic alterations in the spliced gene, altered expression of both core components or regulators of the precursor messenger RNA (pre-mRNA) splicing machinery, or both, are major drivers of tumorigenesis. Hence, in this review we provide an overview of our current understanding of splicing alterations in cancer, and emphasize the need to further explore the cancer-specific splicing programs in order to obtain new insights in oncology. Furthermore, we also discuss the recent advances in the identification of dysregulated splicing signatures on a genome-wide scale and their potential use as biomarkers. Finally, we highlight the therapeutic opportunities arising from dysregulated splicing and summarize the current approaches to therapeutically target AS in cancer.
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Affiliation(s)
- Cláudia Bessa
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, 1649-016 Lisbon, Portugal; (C.B.); (P.M.)
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
| | - Paulo Matos
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, 1649-016 Lisbon, Portugal; (C.B.); (P.M.)
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
| | - Peter Jordan
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, 1649-016 Lisbon, Portugal; (C.B.); (P.M.)
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
- Correspondence: (P.J.); (V.G.); Tel.: +351-217-519-380 (P.J.)
| | - Vânia Gonçalves
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, 1649-016 Lisbon, Portugal; (C.B.); (P.M.)
- BioISI—Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
- Correspondence: (P.J.); (V.G.); Tel.: +351-217-519-380 (P.J.)
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Gonçalves V, Henriques AFA, Matos P, Jordan P. Ibuprofen disrupts a WNK1/GSK3β/SRPK1 protein complex required for expression of tumor-related splicing variant RAC1B in colorectal cells. Oncotarget 2020; 11:4421-4437. [PMID: 33315986 PMCID: PMC7720772 DOI: 10.18632/oncotarget.27816] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
A major risk factor promoting tumor development is chronic inflammation and the use of nonsteroidal anti-inflammatory drugs (NSAID), including ibuprofen, can decrease the risk of developing various types of cancer, including colorectal cancer (CRC). Although the molecular mechanism behind the antitumor properties of NSAIDs has been largely attributed to inhibition of cyclooxygenases (COXs), several studies have shown that the chemopreventive properties of ibuprofen also involve multiple COX-independent effects. One example is its ability to inhibit the alternative splicing event generating RAC1B, which is overexpressed in a specific subset of BRAF-mutated colorectal tumors and sustains cell survival. Here we describe the mechanism by which ibuprofen prevents RAC1B alternative splicing in a BRAF mutant CRC cell line: it leads to decreased translocation of SRPK1 and SRSF1 to the nucleus and is regulated by a WNK1/GSK3β/SRPK1 protein kinase complex. Surprisingly, we demonstrate that ibuprofen does not inhibit the activity of any of the involved kinases but rather promotes disassembly of this regulatory complex, exposing GSK3β serine 9 to inhibitory phosphorylation, namely by AKT, which results in nuclear exclusion of SRPK1 and SRSF1 hypophosphorylation. The data shed new light on the biochemical mechanisms behind ibuprofen’s action on alternative spliced RAC1B and may support its use in personalized approaches to CRC therapy or chemoprevention regimens.
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Affiliation(s)
- Vânia Gonçalves
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, Lisbon, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal.,These authors contributed equally to this work
| | - Andreia F A Henriques
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, Lisbon, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal.,These authors contributed equally to this work
| | - Paulo Matos
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, Lisbon, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
| | - Peter Jordan
- Department of Human Genetics, National Health Institute Dr. Ricardo Jorge, Lisbon, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, Faculty of Sciences, University of Lisbon, Lisbon, Portugal
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Cherry S, Lynch KW. Alternative splicing and cancer: insights, opportunities, and challenges from an expanding view of the transcriptome. Genes Dev 2020; 34:1005-1016. [PMID: 32747477 PMCID: PMC7397854 DOI: 10.1101/gad.338962.120] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Over the past decade there has been increased awareness of the potential role of alternative splicing in the etiology of cancer. In particular, advances in RNA-Sequencing technology and analysis has led to a wave of discoveries in the last few years regarding the causes and functional relevance of alternative splicing in cancer. Here we discuss the current understanding of the connections between splicing and cancer, with a focus on the most recent findings. We also discuss remaining questions and challenges that must be addressed in order to use our knowledge of splicing to guide the diagnosis and treatment of cancer.
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Affiliation(s)
- Sara Cherry
- Department of Pathology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Kristen W Lynch
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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27
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Ozay EI, Shanthalingam S, Torres JA, Osborne BA, Tew GN, Minter LM. Protein Kinase C Theta Modulates PCMT1 through hnRNPL to Regulate FOXP3 Stability in Regulatory T Cells. Mol Ther 2020; 28:2220-2236. [PMID: 32592691 DOI: 10.1016/j.ymthe.2020.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/21/2020] [Accepted: 06/10/2020] [Indexed: 10/24/2022] Open
Abstract
T cell receptor signaling, together with cytokine-induced signals, can differentially regulate RNA processing to influence T helper versus regulatory T cell fate. Protein kinase C family members have been shown to function in alternative splicing and RNA processing in various cell types. T cell-specific protein kinase C theta, a molecular regulator of T cell receptor downstream signaling, has been shown to phosphorylate splicing factors and affect post-transcriptional control of T cell gene expression. In this study, we explored how using a synthetic cell-penetrating peptide mimic for intracellular anti-protein kinase C theta delivery fine-tunes differentiation of induced regulatory T cells through its differential effects on RNA processing. We identified protein kinase C theta signaling as a critical modulator of two key RNA regulatory factors, heterogeneous nuclear ribonucleoprotein L (hnRNPL) and protein-l-isoaspartate O-methyltransferase-1 (PCMT1), and loss of protein kinase C theta function initiated a "switch" in post-transcriptional organization in induced regulatory T cells. More interestingly, we discovered that protein-l-isoaspartate O- methyltransferase-1 acts as an instability factor in induced regulatory T cells, by methylating the forkhead box P3 (FOXP3) promoter. Targeting protein-l-isoaspartate O-methyltransferase-1 using a cell-penetrating antibody revealed an efficient means of modulating RNA processing to confer a stable regulatory T cell phenotype.
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Affiliation(s)
- E Ilker Ozay
- Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Sudarvili Shanthalingam
- Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Joe A Torres
- Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Barbara A Osborne
- Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Gregory N Tew
- Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Polymer Science and Engineering, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Lisa M Minter
- Graduate Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA 01003, USA; Department of Veterinary and Animal Sciences, University of Massachusetts Amherst, Amherst, MA 01003, USA.
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28
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Wang G, Sheng W, Tang J, Li X, Zhou J, Dong M. Cooperation of SRPK2, Numb and p53 in the malignant biology and chemosensitivity of colorectal cancer. Biosci Rep 2020; 40:BSR20191488. [PMID: 31898732 PMCID: PMC6970084 DOI: 10.1042/bsr20191488] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 12/29/2019] [Accepted: 12/31/2019] [Indexed: 01/24/2023] Open
Abstract
Serine-arginine protein kinase 2 (SRPK2) is aberrantly expressed in human malignancies including colorectal cancer (CRC). However, little is known about the molecular mechanisms, and the role of SRPK2 in chemosensitivity remains unexplored in CRC. We recently showed that SRPK2 promotes pancreatic cancer progression by down-regulating Numb and p53. Therefore, we investigated the cooperation between SRPK2, Numb and p53 in the cell migration, invasion and chemosensitivity of CRC in vitro. Here, we showed that SRPK2 expression was higher in CRC tumors than in nontumor tissues. SRPK2 expression was positively associated with clinicopathological characteristics of CRC patients, including tumor differentiation, T stage, N stage and UICC stage. Additionally, SRPK2 had no association with mutant p53 (mtp53) in SW480 and SW620 cells, but negatively regulated Numb and wild-type p53 (wtp53) in response to 5-fluorouracil or cisplatin treatment in HCT116 cells. Moreover, SRPK2, Numb and p53 coimmunoprecipitated into a triple complex with or without the treatment of 5-fluorouracil in HCT116 cells, and p53 knockdown reversed the up-regulation of wtp53 induced by SRPK2 silencing with chemical agent treatment. Furthermore, overexpression of SRPK2 increased cell migration and invasion and decreased chemosensitivity to 5-fluorouracil or cisplatin in HCT116 cells. Conversely, SRPK2 silencing decreased cell migration and invasion and increased chemosensitivity to 5-fluorouracil or cisplatin, yet these effects could be reversed by p53 knockdown under chemical agent treatment. These results thus reveal a novel role of SRPK2-Numb-p53 signaling in the progression of CRC and demonstrate that SRPK2 is a potential therapeutic target for CRC clinical therapy.
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Affiliation(s)
- Guosen Wang
- Department of General Surgery, The First Affliated Hospital, Nanchang University, Nanchang 330006, Jiangxi, China
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Weiwei Sheng
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Jingtong Tang
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Xin Li
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Jianping Zhou
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
| | - Ming Dong
- Department of Gastrointestinal Surgery, The First Hospital, China Medical University, Shenyang 110001, Liaoning, China
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29
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Bhadra M, Howell P, Dutta S, Heintz C, Mair WB. Alternative splicing in aging and longevity. Hum Genet 2019; 139:357-369. [PMID: 31834493 DOI: 10.1007/s00439-019-02094-6] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 11/24/2019] [Indexed: 12/13/2022]
Abstract
Alternative pre-mRNA splicing increases the complexity of the proteome that can be generated from the available genomic coding sequences. Dysregulation of the splicing process has been implicated in a vast repertoire of diseases. However, splicing has recently been linked to both the aging process itself and pro-longevity interventions. This review focuses on recent research towards defining RNA splicing as a new hallmark of aging. We highlight dysfunctional alternative splicing events that contribute to the aging phenotype across multiple species, along with recent efforts toward deciphering mechanistic roles for RNA splicing in the regulation of aging and longevity. Further, we discuss recent research demonstrating a direct requirement for specific splicing factors in pro-longevity interventions, and specifically how nutrient signaling pathways interface to splicing factor regulation and downstream splicing targets. Finally, we review the emerging potential of using splicing profiles as a predictor of biological age and life expectancy. Understanding the role of RNA splicing components and downstream targets altered in aging may provide opportunities to develop therapeutics and ultimately extend healthy lifespan in humans.
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Affiliation(s)
- Malini Bhadra
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Porsha Howell
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Sneha Dutta
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Caroline Heintz
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - William B Mair
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
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Rahm M, Merl-Pham J, Adamski J, Hauck SM. Time-resolved phosphoproteomic analysis elucidates hepatic 11,12-Epoxyeicosatrienoic acid signaling pathways. Prostaglandins Other Lipid Mediat 2019; 146:106387. [PMID: 31669255 DOI: 10.1016/j.prostaglandins.2019.106387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 09/24/2019] [Accepted: 10/16/2019] [Indexed: 01/20/2023]
Abstract
Epoxyeicosatrienoic acids (EETs) are potent lipid mediators with well-established effects in vascular tissues. Recent studies indicated an emerging role of these eicosanoids in metabolic diseases and the EET signaling pathway was shown to be involved in hepatic insulin sensitivity. However, compared to vascular tissues, there is only limited knowledge about the underlying signaling pathways in the liver. Therefore, we employed an LC-MS/MS-based time-resolved phosphoproteomics approach to characterize 11,12-EET-mediated signaling events in the liver cell line Hepa 1-6. 11,12-EET treatment resulted in the time-dependent regulation of phosphopeptides involved in processes as yet unknown to be affected by EETs, including RNA processing, splicing and translation regulation. Pathway analysis combined with western blot-based validation revealed enhanced AKT/mTOR/p70S6K signaling as demonstrated by increased acute phosphorylation of AKT (Ser473) and p70S6K (Thr389). In addition, 11,12-EET treatment led to differential regulation of phosphopeptides including important mediators of the DNA damage response and we observed a prolonged induction of the etoposide-induced DNA damage marker γH2AX in response to 11,12-EET. In summary, our findings extend current knowledge of 11,12-EET signaling events and emphasize the importance of the AKT/mTOR/p70S6K pathway in hepatic 11,12-EET signaling. Based on the results presented in this study, we furthermore propose a novel role of EET signaling in the regulation of the DNA damage response.
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Affiliation(s)
- Marco Rahm
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstädter Landstraße 1, D-85764, Neuherberg, Germany
| | - Juliane Merl-Pham
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstädter Landstraße 1, D-85764, Neuherberg, Germany
| | - Jerzy Adamski
- Research Unit Molecular Endocrinology and Metabolism, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstädter Landstraße 1, D-85764, Neuherberg, Germany; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, Ingolstädter Landstraße 1, D-85764, Neuherberg, Germany.
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31
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Desterke C, Gassama-Diagne A. Protein-protein interaction analysis highlights the role of septins in membrane enclosed lumen and mRNA processing. Adv Biol Regul 2019; 73:100635. [PMID: 31420262 DOI: 10.1016/j.jbior.2019.100635] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/01/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
Septins are a family of GTP-binding proteins that assemble into non-polar filaments which can be recruited to negatively charged membranes and serve as a scaffold to recruit cytosolic proteins and cytoskeletal elements such as microtubules and actin so that they can perform their important biological functions. Human septins consist of four groups, each with 13 members, and filaments formation usually involve members from each group in specific positions. However, little is known about the molecular mechanisms that drive the binding of septins to membranes and its importance to their biological functions. Here we have built a protein-protein interaction (PPI) network around human septins and highlighted the connections with 170 partners. Functional enrichment by inference of the network of septins and their partners revealed their participation in functions consistent with some of the roles described for septins, including cell cycle, cell division and cell shape, but we also identified septin partners in these functions that had not previously been described. Interestingly, we identified important and multiple connections between septins and mRNA processing and their export from the nucleus. Analysis of the enrichment of gene ontology cellular components highlighted some important interactions between molecules involved in the spliceosome with septin 2 and septin 7 in particular. RNA splicing regulates gene expression, and through it, cell fate, development and physiology. Mutations in components of the in the splicing machinery is linked to several diseases including cancer, thus taken together, the different analyses presented here open new perspectives to elucidate the pathobiological role of septins.
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Affiliation(s)
| | - Ama Gassama-Diagne
- INSERM, Unité 1193, Villejuif, F-94800, France; Université Paris-Sud, UMR-S 1193, Villejuif, F-94800, France.
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32
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More than a messenger: Alternative splicing as a therapeutic target. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194395. [PMID: 31271898 DOI: 10.1016/j.bbagrm.2019.06.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/18/2019] [Accepted: 06/19/2019] [Indexed: 12/30/2022]
Abstract
Alternative splicing of pre-mRNA is an essential post- and co-transcriptional mechanism of gene expression regulation that produces multiple mature mRNA transcripts from a single gene. Genetic mutations that affect splicing underlie numerous devastating diseases. The complexity of splicing regulation allows for multiple therapeutic approaches to correct disease-associated mis-splicing events. In this review, we first highlight recent findings from therapeutic strategies that have used splice switching antisense oligonucleotides and small molecules that bind directly to RNA. Second, we summarize different genetic and chemical approaches to target components of the spliceosome to correct splicing defects in pathological conditions. Finally, we present an overview of compounds that target kinases and accessory pathways that intersect with the splicing machinery. Advancements in the understanding of disease-specific defects caused by mis-regulation of alternative splicing will certainly increase the development of therapeutic options for the clinic. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Song Q, Yi F, Zhang Y, Jun Li DK, Wei Y, Yu H, Zhang Y. CRKL regulates alternative splicing of cancer-related genes in cervical cancer samples and HeLa cell. BMC Cancer 2019; 19:499. [PMID: 31133010 PMCID: PMC6537309 DOI: 10.1186/s12885-019-5671-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 05/02/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aberrant spliced isoforms are specifically associated with cancer progression and metastasis. The cytoplasmic adaptor CRKL (v-crk avian sarcoma virus CT10 oncogene homolog-like) is a CRK like proto-oncogene, which encodes a SH2 and SH3 (src homology) domain-containing adaptor protein. CRKL is tightly linked to leukemia via its binding partners BCR-ABL and TEL-ABL, upregulated in multiple types of human cancers, and induce cancer cell proliferation and invasion. However, it remains unclear whether signaling adaptors such as CRKL could regulate alternative splicing. METHODS We analyzed the expression level of CRKL in 305 cervical cancer tissue samples available in TCGA database, and then selected two groups of cancer samples with CRKL differentially expressed to analyzed potential CRKL-regulated alternative splicing events (ASEs). CRKL was knocked down by shRNA to further study CRKL-regulated alternative splicing and the activity of SR protein kinases in HeLa cells using RNA-Seq and Western blot techniques. We validated 43 CRKL-regulated ASEs detected by RNA-seq in HeLa cells, using RT-qPCR analysis of HeLa cell samples and using RNA-seq data of the two group of clinical cervical samples. RESULTS The expression of CRKL was mostly up-regulated in stage I cervical cancer samples. Knock-down of CRKL led to a reduced cell proliferation. CRKL-regulated alternative splicing of a large number of genes were enriched in cancer-related functional pathways, among which DNA repair and G2/M mitotic cell cycle, GnRH signaling were shared among the top 10 enriched GO terms and KEGG pathways by results from clinical samples and HeLa cell model. We showed that CRKL-regulated ASEs revealed by computational analysis using ABLas software in HeLa cell were highly validated by RT-qPCR, and also validated by cervical cancer clinical samples. CONCLUSIONS This is the first report of CRKL-regulation of the alternative splicing of a number of genes critical in tumorigenesis and cancer progression, which is consistent with CRKL reported role as a signaling adaptor and a kinase. Our results underline that the signaling adaptor CRKL might integrate the external and intrinsic cellular signals and coordinate the dynamic activation of cellular signaling pathways including alternative splicing regulation.
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Affiliation(s)
- Qingling Song
- Department of Oncology and Radiotherapy, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, Hubei Province, China
| | - Fengtao Yi
- Department of Oncology and Radiotherapy, Wuhan General Hospital of Guangzhou Military Command, Wuhan, 430070, Hubei Province, China.
| | - Yuhong Zhang
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China.,Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China
| | - Daniel K Jun Li
- Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China.,Department of Biology and Biotechnology, School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, 430070, Hubei, China
| | - Yaxun Wei
- Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China
| | - Han Yu
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China
| | - Yi Zhang
- Laboratory of Human Health and Genome Regulation, Wuhan, 430075, Hubei, China. .,Center for Genome Analysis, ABLife Inc, Wuhan, 430075, Hubei, China.
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Krasnov GS, Kudryavtseva AV, Snezhkina AV, Lakunina VA, Beniaminov AD, Melnikova NV, Dmitriev AA. Pan-Cancer Analysis of TCGA Data Revealed Promising Reference Genes for qPCR Normalization. Front Genet 2019; 10:97. [PMID: 30881377 PMCID: PMC6406071 DOI: 10.3389/fgene.2019.00097] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 01/29/2019] [Indexed: 11/20/2022] Open
Abstract
Quantitative PCR (qPCR) remains the most widely used technique for gene expression evaluation. Obtaining reliable data using this method requires reference genes (RGs) with stable mRNA level under experimental conditions. This issue is especially crucial in cancer studies because each tumor has a unique molecular portrait. The Cancer Genome Atlas (TCGA) project provides RNA-Seq data for thousands of samples corresponding to dozens of cancers and presents the basis for assessment of the suitability of genes as reference ones for qPCR data normalization. Using TCGA RNA-Seq data and previously developed CrossHub tool, we evaluated mRNA level of 32 traditionally used RGs in 12 cancer types, including those of lung, breast, prostate, kidney, and colon. We developed an 11-component scoring system for the assessment of gene expression stability. Among the 32 genes, PUM1 was one of the most stably expressed in the majority of examined cancers, whereas GAPDH, which is widely used as a RG, showed significant mRNA level alterations in more than a half of cases. For each of 12 cancer types, we suggested a pair of genes that are the most suitable for use as reference ones. These genes are characterized by high expression stability and absence of correlation between their mRNA levels. Next, the scoring system was expanded with several features of a gene: mutation rate, number of transcript isoforms and pseudogenes, participation in cancer-related processes on the basis of Gene Ontology, and mentions in PubMed-indexed articles. All the genes covered by RNA-Seq data in TCGA were analyzed using the expanded scoring system that allowed us to reveal novel promising RGs for each examined cancer type and identify several "universal" pan-cancer RG candidates, including SF3A1, CIAO1, and SFRS4. The choice of RGs is the basis for precise gene expression evaluation by qPCR. Here, we suggested optimal pairs of traditionally used RGs for 12 cancer types and identified novel promising RGs that demonstrate high expression stability and other features of reliable and convenient RGs (high expression level, low mutation rate, non-involvement in cancer-related processes, single transcript isoform, and absence of pseudogenes).
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Affiliation(s)
- George S. Krasnov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | | | | | | | | | | | - Alexey A. Dmitriev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
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35
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Latorre E, Ostler EL, Faragher RGA, Harries LW. FOXO1 and ETV6 genes may represent novel regulators of splicing factor expression in cellular senescence. FASEB J 2019; 33:1086-1097. [PMID: 30088951 DOI: 10.1096/fj.201801154r] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2023]
Abstract
Cellular plasticity is a key facet of cellular homeostasis requiring correct temporal and spatial patterns of alternative splicing. Splicing factors, which orchestrate this process, demonstrate age-related dysregulation of expression; they are emerging as potential influences on aging and longevity. The upstream drivers of these alterations are still unclear but may involve aberrant cellular signaling. We compared the phosphorylation status of proteins in multiple signaling pathways in early and late passage human primary fibroblasts. We then assessed the impact of chemical inhibition or targeted knockdown of direct downstream targets of the ERK and AKT pathways on splicing factor expression, cellular senescence, and proliferation kinetics in senescent primary human fibroblasts. Components of the ERK and AKT signaling pathways demonstrated altered activation during cellular aging. Inhibition of AKT and ERK pathways led to up-regulation of splicing factor expression, reduction in senescent cell load, and partial reversal of multiple cellular senescence phenotypes in a dose-dependent manner. Furthermore, targeted knockdown of the genes encoding the downstream targets FOXO1 or ETV6 was sufficient to mimic these observations. Our results suggest that age-associated dysregulation of splicing factor expression and cellular senescence may derive in part from altered activity of ERK and AKT signaling and may act in part through the ETV6 and FOXO1 transcription factors. Targeting the activity of downstream effectors of ERK and AKT may therefore represent promising targets for future therapeutic intervention.-Latorre, E., Ostler, E. L., Faragher, R. G. A., Harries, L. W. FOXO1 and ETV6 genes may represent novel regulators of splicing factor expression in cellular senescence.
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Affiliation(s)
- Eva Latorre
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Devon, United Kingdom; and
| | - Elizabeth L Ostler
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Richard G A Faragher
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, United Kingdom
| | - Lorna W Harries
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, University of Exeter, Devon, United Kingdom; and
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36
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View from an mRNP: The Roles of SR Proteins in Assembly, Maturation and Turnover. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:83-112. [PMID: 31811631 DOI: 10.1007/978-3-030-31434-7_3] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Serine- and arginine-rich proteins (SR proteins) are a family of multitasking RNA-binding proteins (RBPs) that are key determinants of messenger ribonucleoprotein (mRNP) formation, identity and fate. Apart from their essential functions in pre-mRNA splicing, SR proteins display additional pre- and post-splicing activities and connect nuclear and cytoplasmic gene expression machineries. Through changes in their post-translational modifications (PTMs) and their subcellular localization, they provide functional specificity and adjustability to mRNPs. Transcriptome-wide UV crosslinking and immunoprecipitation (CLIP-Seq) studies revealed that individual SR proteins are present in distinct mRNPs and act in specific pairs to regulate different gene expression programmes. Adopting an mRNP-centric viewpoint, we discuss the roles of SR proteins in the assembly, maturation, quality control and turnover of mRNPs and describe the mechanisms by which they integrate external signals, coordinate their multiple tasks and couple subsequent mRNA processing steps.
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37
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Black AJ, Schilder RJ, Kimball SR. Palmitate- and C6 ceramide-induced Tnnt3 pre-mRNA alternative splicing occurs in a PP2A dependent manner. Nutr Metab (Lond) 2018; 15:87. [PMID: 30564278 PMCID: PMC6296074 DOI: 10.1186/s12986-018-0326-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/10/2018] [Indexed: 12/24/2022] Open
Abstract
Background In a previous study, we showed that consumption of diets enriched in saturated fatty acids causes changes in alternative splicing of pre-mRNAs encoding a number of proteins in rat skeletal muscle, including the one encoding skeletal muscle Troponin T (Tnnt3). However, whether saturated fatty acids act directly on muscle cells to modulate alternative pre-mRNA splicing was not assessed. Moreover, the signaling pathway through which saturated fatty acids act to promote changes in alternative splicing is unknown. Therefore, the objective of the present study was to characterize the signaling pathway through which saturated fatty acids act to modulate Tnnt3 alternative splicing. Methods The effects of treatment of L6 myotubes with saturated (palmitate), mono- (oleate), or polyunsaturated (linoleate) fatty acids on alternative splicing of pre-mRNA was assessed using Tnnt3 as a marker gene. Results Palmitate treatment caused a two-fold change (p < 0.05) in L6 myotube Tnnt3 alternative splicing whereas treatment with either oleate or linoleate had minimal effects compared to control myotubes. Treatment with a downstream metabolite of palmitate, ceramide, had effects similar to palmitate on Tnnt3 alternative splicing and inhibition of de novo ceramide biosynthesis blocked the palmitate-induced alternative splicing changes. The effects of palmitate and ceramide on Tnnt3 alternative splicing were accompanied by a 40–50% reduction in phosphorylation of Akt on S473. However, inhibition of de novo ceramide biosynthesis did not prevent palmitate-induced Akt dephosphorylation, suggesting that palmitate may act in an Akt-independent manner to modulate Tnnt3 alternative splicing. Instead, pre-treatment with okadaic acid at concentrations that selectively inhibit protein phosphatase 2A (PP2A) blocked both palmitate- and ceramide-induced changes in Tnnt3 alternative splicing, suggesting that palmitate and ceramide act through PP2A to modulate Tnnt3 alternative splicing. Conclusions Overall, the data show that fatty acid saturation level and ceramides are important factors modulating alternative pre-mRNA splicing through activation of PP2A. Electronic supplementary material The online version of this article (10.1186/s12986-018-0326-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Adam J Black
- 1Department of Cellular and Molecular Physiology, Penn State College of Medicine, H166, 500 University Drive, Hershey, PA 17033 USA.,Present Address: Department of Cell Biology and Physiology, 6330 Medical Biomolecular Research Building, 111 Mason Farm Rd, Chapel Hill, NC 27599 USA
| | - Rudolf J Schilder
- 3Department of Entomology and Biology, Penn State University, University Park, PA USA
| | - Scot R Kimball
- 1Department of Cellular and Molecular Physiology, Penn State College of Medicine, H166, 500 University Drive, Hershey, PA 17033 USA
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38
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Xu L, Zhang H, Mei M, Du C, Huang X, Li J, Wang Y, Bao S, Zheng H. Phosphorylation of serine/arginine-rich splicing factor 1 at tyrosine 19 promotes cell proliferation in pediatric acute lymphoblastic leukemia. Cancer Sci 2018; 109:3805-3815. [PMID: 30320932 PMCID: PMC6272096 DOI: 10.1111/cas.13834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 09/21/2018] [Accepted: 10/04/2018] [Indexed: 12/21/2022] Open
Abstract
Serine/arginine‐rich splicing factor 1 (SRSF1) has been linked to various human cancers including pediatric acute lymphoblastic leukemia (ALL). Our previous study has shown that SRSF1 potentially contributes to leukemogenesis; however, its underlying mechanism remains unclear. In this study, leukemic cells were isolated from pediatric ALL bone marrow samples, followed by immunoprecipitation assays and mass spectrometry analysis specific to SRSF1. Subcellular localization of the SRSF1 protein and its mutants were analyzed by immunofluorescence staining. Cell growth, colony formation, cell apoptosis, and the cell cycle were investigated using stable leukemic cell lines generated with lentivirus‐mediated overexpressed WT or mutant plasmids. Cytotoxicity of the Tie2 kinase inhibitor was also evaluated. Our results showed the phosphorylation of SRSF1 at tyrosine 19 (Tyr‐19) was identified in newly diagnosed ALL samples, but not in complete remission or normal control samples. Compared to the SRSF1 WT cells, the missense mutants of the Tyr‐19 phosphorylation affected the subcellular localization of SRSF1. In addition, the Tyr‐19 phosphorylation of SRSF1 also led to increased cell proliferation and enhanced colony‐forming properties by promoting the cell cycle. Remarkably, we further identified the kinase Tie2 as a potential therapeutic target in leukemia cells. In conclusion, we identify for the first time that the phosphorylation state of SRSF1 is linked to different phases in pediatric ALL. The Tyr‐19 phosphorylation of SRSF1 disrupts its subcellular localization and promotes proliferation in leukemia cells by driving cell‐cycle progression. Inhibitors targeting Tie2 kinase that could catalyze Tyr‐19 phosphorylation of SRSF1 offer a promising therapeutic target for treatment of pediatric ALL.
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Affiliation(s)
- Liting Xu
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Han Zhang
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Mei Mei
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Chaohao Du
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Xiahe Huang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Jing Li
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
| | - Yingchun Wang
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Shilai Bao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Huyong Zheng
- Beijing Key Laboratory of Pediatric Hematology Oncology, National Key Discipline of Pediatrics, Ministry of Education, Key Laboratory of Major Diseases in Children, Ministry of Education, Hematology Oncology Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing, China
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39
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Liu X, Klein PS. Glycogen synthase kinase-3 and alternative splicing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1501. [PMID: 30118183 DOI: 10.1002/wrna.1501] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/03/2018] [Accepted: 07/09/2018] [Indexed: 12/16/2022]
Abstract
Glycogen synthase kinase-3 (GSK-3) is a highly conserved negative regulator of receptor tyrosine kinase, cytokine, and Wnt signaling pathways. Stimulation of these pathways inhibits GSK-3 to modulate diverse downstream effectors that include transcription factors, nutrient sensors, glycogen synthesis, mitochondrial function, circadian rhythm, and cell fate. GSK-3 also regulates alternative splicing in response to T-cell receptor activation, and recent phosphoproteomic studies have revealed that multiple splicing factors and regulators of RNA biosynthesis are phosphorylated in a GSK-3-dependent manner. Furthermore, inhibition of GSK-3 alters the splicing of hundreds of mRNAs, indicating a broad role for GSK-3 in the regulation of RNA processing. GSK-3-regulated phosphoproteins include SF3B1, SRSF2, PSF, RBM8A, nucleophosmin 1 (NPM1), and PHF6, many of which are mutated in leukemia and myelodysplasia. As GSK-3 is inhibited by pathways that are pathologically activated in leukemia and loss of Gsk3 in hematopoietic cells causes a severe myelodysplastic neoplasm in mice, these findings strongly implicate GSK-3 as a critical regulator of mRNA processing in normal and malignant hematopoiesis. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing RNA in Disease and Development > RNA in Disease RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Xiaolei Liu
- Division of Hematology-Oncology, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Peter S Klein
- Division of Hematology-Oncology, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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40
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Urbanski L, Leclair N, Anczuków O. Alternative-splicing defects in cancer: Splicing regulators and their downstream targets, guiding the way to novel cancer therapeutics. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1476. [PMID: 29693319 PMCID: PMC6002934 DOI: 10.1002/wrna.1476] [Citation(s) in RCA: 205] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/14/2022]
Abstract
Defects in alternative splicing are frequently found in human tumors and result either from mutations in splicing-regulatory elements of specific cancer genes or from changes in the regulatory splicing machinery. RNA splicing regulators have emerged as a new class of oncoproteins and tumor suppressors, and contribute to disease progression by modulating RNA isoforms involved in the hallmark cancer pathways. Thus, dysregulation of alternative RNA splicing is fundamental to cancer and provides a potentially rich source of novel therapeutic targets. Here, we review the alterations in splicing regulatory factors detected in human tumors, as well as the resulting alternatively spliced isoforms that impact cancer hallmarks, and discuss how they contribute to disease pathogenesis. RNA splicing is a highly regulated process and, as such, the regulators are themselves tightly regulated. Differential transcriptional and posttranscriptional regulation of splicing factors modulates their levels and activities in tumor cells. Furthermore, the composition of the tumor microenvironment can also influence which isoforms are expressed in a given cell type and impact drug responses. Finally, we summarize current efforts in targeting alternative splicing, including global splicing inhibition using small molecules blocking the spliceosome or splicing-factor-modifying enzymes, as well as splice-switching RNA-based therapeutics to modulate cancer-specific splicing isoforms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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41
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Antonopoulou E, Ladomery M. Targeting Splicing in Prostate Cancer. Int J Mol Sci 2018; 19:ijms19051287. [PMID: 29693622 PMCID: PMC5983716 DOI: 10.3390/ijms19051287] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/18/2018] [Accepted: 04/23/2018] [Indexed: 12/22/2022] Open
Abstract
Over 95% of human genes are alternatively spliced, expressing splice isoforms that often exhibit antagonistic functions. We describe genes whose alternative splicing has been linked to prostate cancer; namely VEGFA, KLF6, BCL2L2, ERG, and AR. We discuss opportunities to develop novel therapies that target specific splice isoforms, or that target the machinery of splicing. Therapeutic approaches include the development of small molecule inhibitors of splice factor kinases, splice isoform specific siRNAs, and splice switching oligonucleotides.
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Affiliation(s)
- Effrosyni Antonopoulou
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK.
| | - Michael Ladomery
- Faculty of Health and Applied Sciences, University of the West of England, Coldharbour Lane, Bristol BS16 1QY, UK.
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42
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Galan-Davila AK, Ryu J, Dong K, Xiao Y, Dai Z, Zhang D, Li Z, Dick AM, Liu KD, Kamat A, Lu M, Dong Q, Liu F, Dong LQ. Alternative splicing variant of the scaffold protein APPL1 suppresses hepatic adiponectin signaling and function. J Biol Chem 2018; 293:6064-6074. [PMID: 29483192 DOI: 10.1074/jbc.ra118.002162] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/09/2018] [Indexed: 11/06/2022] Open
Abstract
Adiponectin is an adipocyte-derived hormone with antidiabetic activities that include increasing the sensitivity of cells to insulin. Adaptor protein containing pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif (APPL1) stimulates adiponectin signaling and promotes adiponectin's insulin-sensitizing effects by binding to two adiponectin receptors, AdipoR1 and AdipoR2, and the insulin receptor. In this study, we report an alternative splicing variant of APPL1 (APPL1sv) that is highly expressed in mouse liver, pancreas, and spleen tissues. The expression levels of APPL1sv in liver tissues were enhanced in a mouse model of obesity and diabetic dyslipidemia (i.e. db/db mice) and reduced in calorie-restricted mice compared with ad libitum-fed mice. APPL1sv overexpression or suppression inhibited or enhanced, respectively, adiponectin-stimulated phosphorylation of AMP protein kinase (AMPK) in mouse hepatocytes. We also found that APPL1sv binds to AdipoR1 and AdipoR2 under basal conditions and that adiponectin treatment reduces this binding. Overexpression of APPL1sv blocked adiponectin-induced interactions of APPL1 with the adiponectin receptors. Moreover, adenovirus-mediated and short hairpin RNA-based suppression of APPL1sv greatly reduced high fat diet-induced insulin resistance and hepatic glucose production in mice. Our study identifies a key suppressor of hepatic adiponectin signaling and insulin sensitivity, a finding that may shed light on identifying effective therapeutic targets for treating insulin resistance and type 2 diabetes.
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Affiliation(s)
- Amanda K Galan-Davila
- From the Departments of Cell Systems and Anatomy.,the Department of Clinical and Applied Science Education, University of the Incarnate Word School of Osteopathic Medicine, San Antonio, Texas 78253
| | - Jiyoon Ryu
- From the Departments of Cell Systems and Anatomy
| | - Kun Dong
- From the Departments of Cell Systems and Anatomy
| | - Yang Xiao
- From the Departments of Cell Systems and Anatomy
| | - Zhe Dai
- From the Departments of Cell Systems and Anatomy
| | - Deling Zhang
- From the Departments of Cell Systems and Anatomy
| | - Zhi Li
- From the Departments of Cell Systems and Anatomy
| | | | - Kevin D Liu
- From the Departments of Cell Systems and Anatomy
| | - Amrita Kamat
- Medicine and.,The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900.,the Geriatric Research Education and Clinical Center (GRECC), South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Min Lu
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093.,the Merck Research Laboratory, Diabetes Early Discovery, Boston, Massachusetts 02115-5727
| | - Qunfeng Dong
- the Center for Biomedical Informatics, Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153, and
| | - Feng Liu
- The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900.,Pharmacology, and
| | - Lily Q Dong
- From the Departments of Cell Systems and Anatomy, .,The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900
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43
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Signaling Pathways Driving Aberrant Splicing in Cancer Cells. Genes (Basel) 2017; 9:genes9010009. [PMID: 29286307 PMCID: PMC5793162 DOI: 10.3390/genes9010009] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/07/2017] [Accepted: 12/18/2017] [Indexed: 12/17/2022] Open
Abstract
Aberrant profiles of pre-mRNA splicing are frequently observed in cancer. At the molecular level, an altered profile results from a complex interplay between chromatin modifications, the transcriptional elongation rate of RNA polymerase, and effective binding of the spliceosome to the generated transcripts. Key players in this interplay are regulatory splicing factors (SFs) that bind to gene-specific splice-regulatory sequence elements. Although mutations in genes of some SFs were described, a major driver of aberrant splicing profiles is oncogenic signal transduction pathways. Signaling can affect either the transcriptional expression levels of SFs or the post-translational modification of SF proteins, and both modulate the ratio of nuclear versus cytoplasmic SFs in a given cell. Here, we will review currently known mechanisms by which cancer cell signaling, including the mitogen-activated protein kinases (MAPK), phosphatidylinositol 3 (PI3)-kinase pathway (PI3K) and wingless (Wnt) pathways but also signals from the tumor microenvironment, modulate the activity or subcellular localization of the Ser/Arg rich (SR) proteins and heterogeneous nuclear ribonucleoproteins (hnRNPs) families of SFs.
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44
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Passacantilli I, Frisone P, De Paola E, Fidaleo M, Paronetto MP. hnRNPM guides an alternative splicing program in response to inhibition of the PI3K/AKT/mTOR pathway in Ewing sarcoma cells. Nucleic Acids Res 2017; 45:12270-12284. [PMID: 29036465 PMCID: PMC5716164 DOI: 10.1093/nar/gkx831] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 09/12/2017] [Indexed: 01/10/2023] Open
Abstract
Ewing sarcomas (ES) are biologically aggressive tumors of bone and soft tissues for which no cure is currently available. Most ES patients do not respond to chemotherapeutic treatments or acquire resistance. Since the PI3K/AKT/mTOR axis is often deregulated in ES, its inhibition offers therapeutic perspective for these aggressive tumors. Herein, by using splicing sensitive arrays, we have uncovered an extensive splicing program activated upon inhibition of the PI3K/AKT/mTOR signaling pathway by BEZ235. Bioinformatics analyses identified hnRNPM as a key factor in this response. HnRNPM motifs were significantly enriched in introns flanking the regulated exons and proximity of binding represented a key determinant for hnRNPM-dependent splicing regulation. Knockdown of hnRNPM expression abolished a subset of BEZ235-induced splicing changes that contained hnRNPM binding sites, enhanced BEZ235 cytotoxicity and limited the clonogenicity of ES cells. Importantly, hnRNPM up-regulation correlates with poor outcome in sarcoma patients. These findings uncover an hnRNPM-dependent alternative splicing program set in motion by inhibition of the mTOR/AKT/PI3K pathway in ES cells that limits therapeutic efficacy of pharmacologic inhibitors, suggesting that combined inhibition of the PI3K/AKT/mTOR pathway and hnRNPM activity may represent a novel approach for ES treatment.
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Affiliation(s)
- Ilaria Passacantilli
- Laboratory of Cellular and Molecular Neurobiology, Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Paola Frisone
- Laboratory of Cellular and Molecular Neurobiology, Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Elisa De Paola
- Laboratory of Cellular and Molecular Neurobiology, Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy.,University of Rome 'Foro Italico', Piazza Lauro de Bosis 6, 00135 Rome, Italy
| | - Marco Fidaleo
- Laboratory of Cellular and Molecular Neurobiology, Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy
| | - Maria Paola Paronetto
- Laboratory of Cellular and Molecular Neurobiology, Fondazione Santa Lucia, Via del Fosso di Fiorano, 64, 00143 Rome, Italy.,University of Rome 'Foro Italico', Piazza Lauro de Bosis 6, 00135 Rome, Italy
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45
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Jyotsana N, Heuser M. Exploiting differential RNA splicing patterns: a potential new group of therapeutic targets in cancer. Expert Opin Ther Targets 2017; 22:107-121. [PMID: 29235382 DOI: 10.1080/14728222.2018.1417390] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
INTRODUCTION Mutations in genes associated with splicing have been found in hematologic malignancies, but also in solid cancers. Aberrant cancer specific RNA splicing either results from mutations or misexpression of the spliceosome genes directly, or from mutations in splice sites of oncogenes or tumor suppressors. Areas covered: In this review, we present molecular targets of aberrant splicing in various malignancies, information on existing and emerging therapeutics against such targets, and strategies for future drug development. Expert opinion: Alternative splicing is an important mechanism that controls gene expression, and hence pharmacologic and genetic control of aberrant alternative RNA splicing has been proposed as a potential therapy in cancer. To identify and validate aberrant RNA splicing patterns as therapeutic targets we need to (1) characterize the most common genetic aberrations of the spliceosome and of splice sites, (2) understand the dysregulated downstream pathways and (3) exploit in-vivo disease models of aberrant splicing. Antisense oligonucleotides show promising activity, but will benefit from improved delivery tools. Inhibitors of mutated splicing factors require improved specificity, as alternative and aberrant splicing are often intertwined like two sides of the same coin. In summary, targeting aberrant splicing is an early but emerging field in cancer treatment.
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Affiliation(s)
- Nidhi Jyotsana
- a Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation , Hannover Medical School , Hannover , Germany
| | - Michael Heuser
- a Department of Hematology, Hemostasis, Oncology and Stem Cell Transplantation , Hannover Medical School , Hannover , Germany
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46
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Pozzi B, Bragado L, Will CL, Mammi P, Risso G, Urlaub H, Lührmann R, Srebrow A. SUMO conjugation to spliceosomal proteins is required for efficient pre-mRNA splicing. Nucleic Acids Res 2017; 45:6729-6745. [PMID: 28379520 PMCID: PMC5499870 DOI: 10.1093/nar/gkx213] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 03/24/2017] [Indexed: 12/26/2022] Open
Abstract
Pre-mRNA splicing is catalyzed by the spliceosome, a multi-megadalton ribonucleoprotein machine. Previous work from our laboratory revealed the splicing factor SRSF1 as a regulator of the SUMO pathway, leading us to explore a connection between this pathway and the splicing machinery. We show here that addition of a recombinant SUMO-protease decreases the efficiency of pre-mRNA splicing in vitro. By mass spectrometry analysis of anti-SUMO immunoprecipitated proteins obtained from purified splicing complexes formed along the splicing reaction, we identified spliceosome-associated SUMO substrates. After corroborating SUMOylation of Prp3 in cultured cells, we defined Lys 289 and Lys 559 as bona fide SUMO attachment sites within this spliceosomal protein. We further demonstrated that a Prp3 SUMOylation-deficient mutant while still capable of interacting with U4/U6 snRNP components, is unable to co-precipitate U2 and U5 snRNA and the spliceosomal proteins U2-SF3a120 and U5-Snu114. This SUMOylation-deficient mutant fails to restore the splicing of different pre-mRNAs to the levels achieved by the wild type protein, when transfected into Prp3-depleted cultured cells. This mutant also shows a diminished recruitment to active spliceosomes, compared to the wild type protein. These findings indicate that SUMO conjugation plays a role during the splicing process and suggest the involvement of Prp3 SUMOylation in U4/U6•U5 tri-snRNP formation and/or recruitment.
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Affiliation(s)
- Berta Pozzi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Laureano Bragado
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Cindy L Will
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Pablo Mammi
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Guillermo Risso
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, MPI for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany.,Bioanalytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen, Robert-Koch-Straße 40, D-37075 Göttingen, Germany
| | - Reinhard Lührmann
- Department of Cellular Biochemistry, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Göttingen, Germany
| | - Anabella Srebrow
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Fisiología, Biología Molecular y Celular, Buenos Aires, Argentina.,CONICET-Universidad de Buenos Aires, Instituto de Fisiología, Biología Molecular y Neurociencias (IFIBYNE), Buenos Aires, Argentina
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47
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Kajitani N, Glahder J, Wu C, Yu H, Nilsson K, Schwartz S. hnRNP L controls HPV16 RNA polyadenylation and splicing in an Akt kinase-dependent manner. Nucleic Acids Res 2017; 45:9654-9678. [PMID: 28934469 PMCID: PMC5766200 DOI: 10.1093/nar/gkx606] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 07/04/2017] [Indexed: 11/14/2022] Open
Abstract
Inhibition of the Akt kinase activates HPV16 late gene expression by reducing HPV16 early polyadenylation and by activating HPV16 late L1 mRNA splicing. We identified ‘hot spots’ for RNA binding proteins at the early polyA signal and at splice sites on HPV16 late mRNAs. We observed that hnRNP L was associated with sequences at all HPV16 late splice sites and at the early polyA signal. Akt kinase inhibition resulted in hnRNP L dephosphorylation and reduced association of hnRNP L with HPV16 mRNAs. This was accompanied by an increased binding of U2AF65 and Sam68 to HPV16 mRNAs. Furthermore, siRNA knock-down of hnRNP L or Akt induced HPV16 gene expression. Treatment of HPV16 immortalized keratinocytes with Akt kinase inhibitor reduced hnRNP L binding to HPV16 mRNAs and induced HPV16 L1 mRNA production. Finally, deletion of the hnRNP L binding sites in HPV16 subgenomic expression plasmids resulted in activation of HPV16 late gene expression. In conclusion, the Akt kinase inhibits HPV16 late gene expression at the level of RNA processing by controlling the RNA-binding protein hnRNP L. We speculate that Akt kinase activity upholds an intracellular milieu that favours HPV16 early gene expression and suppresses HPV16 late gene expression.
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Affiliation(s)
- Naoko Kajitani
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Jacob Glahder
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Chengjun Wu
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Haoran Yu
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Kersti Nilsson
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
| | - Stefan Schwartz
- Department of Laboratory Medicine, Lund University, BMC-B13, 223 62 Lund, Sweden
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Lee CC, Chang WH, Chang YS, Liu TY, Chen YC, Wu YC, Chang JG. 4β-Hydroxywithanolide E Modulates Alternative Splicing of Apoptotic Genes in Human Hepatocellular Carcinoma Huh-7 Cells. Sci Rep 2017; 7:7290. [PMID: 28779122 PMCID: PMC5544667 DOI: 10.1038/s41598-017-07472-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/27/2017] [Indexed: 01/31/2023] Open
Abstract
Alternative splicing is a mechanism for increasing protein diversity from a limited number of genes. Studies have demonstrated that aberrant regulation in the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4β-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana and investigated its biological effect in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of various apoptotic genes, including HIPK3, SMAC/DIABLO, and SURVIVIN. We also discovered that the levels of SRSF1 phospho-isoform were decreased and the levels of H3K36me3 were increased in 4bHWE treatment. Knockdown experiments revealed that the splicing site selection of SMAC/DIABLO could be mediated by changes in the level of H3K36me3 in 4bHWE-treated cells. Furthermore, we extended our study to apoptosis-associated molecules, and detected increased levels of poly ADP-ribose polymerase cleavage and the active form of CASPASE-3 in 4bHWE-induced apoptosis. In vivo experiments indicated that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease in tumor size. This study is the first to demonstrate that 4bHWE affects alternative splicing by modulating splicing factors and histone modifications, and provides a novel view of the antitumor mechanism of 4bHWE.
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Affiliation(s)
- Chien-Chin Lee
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan
| | - Wen-Hsin Chang
- Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Ya-Sian Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan.,Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan.,Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Ting-Yuan Liu
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yu-Chia Chen
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Yang-Chang Wu
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Research Center for Natural Products and Drug Development, Kaohsiung Medical University, Kaohsiung, Taiwan. .,Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung, Taiwan.
| | - Jan-Gowth Chang
- Epigenome Research Center, China Medical University Hospital, Taichung, Taiwan. .,Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan. .,Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan. .,Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan.
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49
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Insulin regulates titin pre-mRNA splicing through the PI3K-Akt-mTOR kinase axis in a RBM20-dependent manner. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2363-2371. [PMID: 28676430 DOI: 10.1016/j.bbadis.2017.06.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 06/25/2017] [Accepted: 06/29/2017] [Indexed: 12/13/2022]
Abstract
Titin, a giant sarcomeric protein, is largely responsible for the diastolic properties of the heart. It has two major isoforms, N2B and N2BA due to pre-mRNA splicing regulated mainly by a splicing factor RNA binding motif 20 (RBM20). Mis-splicing of titin pre-mRNA in response to external stimuli may lead to altered ratio of N2B to N2BA, and thus, impaired cardiac contractile function. However, little is known about titin alternative splicing in response to external stimuli. Here, we reported the detailed mechanisms of titin alternative splicing in response to insulin. Insulin treatment in cultured neonatal rat cardiomyocytes (NRCMs) activated the PI3K-Akt-mTOR kinase axis, leading to increased N2B expression in the presence of RBM20, but not in NRCMs in the absence of RBM20. By inhibiting this kinase axis with inhibitors, decreased N2B isoform was observed in NRCMs and also in diabetic rat model treated with streptozotocin, but not in NRCMs and diabetic rats in the absence of RBM20. In addition to the alteration of titin isoform ratios in response to insulin, we found that RBM20 expression was increased in NRCMs with insulin treatment, suggesting that RBM20 levels were also regulated by insulin-induced kinase axis. Further, knockdown of p70S6K1 with siRNA reduced both RBM20 and N2B levels, while knockdown of 4E-BP1 elevated expression levels of RBM20 and N2B. These findings reveal a major signal transduction pathway for insulin-induced titin alternative splicing, and place RBM20 in a central position in the pathway, which is consistent with the reputed role of RBM20 in titin alternative splicing. Findings from this study shed light on gene therapeutic strategies at the molecular level by correction of pre-mRNA mis-splicing.
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Czubaty A, Piekiełko-Witkowska A. Protein kinases that phosphorylate splicing factors: Roles in cancer development, progression and possible therapeutic options. Int J Biochem Cell Biol 2017; 91:102-115. [PMID: 28552434 DOI: 10.1016/j.biocel.2017.05.024] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/16/2017] [Accepted: 05/18/2017] [Indexed: 11/30/2022]
Abstract
Disturbed alternative splicing is a common feature of human tumors. Splicing factors that control alternative splicing are phosphorylated by multiple kinases, including these that specifically add phosphoryl groups to serine-arginine rich proteins (e.g. SR-protein kinases, cdc2-like kinases, topoisomerase 1), and protein kinases that govern key cellular signaling pathways (i.e. AKT). Phosphorylation of splicing factors regulates their subcellular localization and interactions with target transcripts and protein partners, and thus significantly contributes the final result of splicing reactions. In this review we aim to summarize the current knowledge on the role of splicing kinases in cancer. Published studies and recently released data of The Cancer Genome Atlas demonstrate that expressions and activities of splicing kinases are commonly disturbed in cancers. Aberrant functioning of splicing kinases results in changed alternative splicing of tumor suppressors (e.g. p53) and regulators of cell signaling (e.g. MAPKs), apoptosis (e.g. MCL), and angiogenesis (VEGF). Splicing kinases act in complicated regulatory networks in which they mutually affect each other's activity to provide tight control of cellular signaling. Dysregulation of these regulatory networks contributes to oncogenic transformation, uncontrolled proliferation, enhanced migration and invasion. Furthermore, the activities of splicing kinases significantly contribute to cellular responses to genotoxic stress. In conclusion, published data provide strong evidence that splicing kinases emerge as important regulators of key processes governing malignant transformation, progression, and response to therapeutic treatments, suggesting their potential as clinically relevant targets.
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Affiliation(s)
- Alicja Czubaty
- Department of Molecular Biology, Faculty of Biology, University of Warsaw, ul. Miecznikowa 1, 02-096 Warsaw, Poland
| | - Agnieszka Piekiełko-Witkowska
- Department of Biochemistry and Molecular Biology, Centre of Postgraduate Medical Education, ul. Marymoncka 99/103, 01-813 Warsaw, Poland.
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