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Bouton L, Ecoutin A, Malard F, Campagne S. Small molecules modulating RNA splicing: a review of targets and future perspectives. RSC Med Chem 2024; 15:1109-1126. [PMID: 38665842 PMCID: PMC11042171 DOI: 10.1039/d3md00685a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/03/2024] [Indexed: 04/28/2024] Open
Abstract
In eukaryotic cells, RNA splicing is crucial for gene expression. Dysregulation of this process can result in incorrect mRNA processing, leading to aberrant gene expression patterns. Such abnormalities are implicated in many inherited diseases and cancers. Historically, antisense oligonucleotides, which bind to specific RNA targets, have been used to correct these splicing abnormalities. Despite their high specificity of action, these oligonucleotides have drawbacks, such as lack of oral bioavailability and the need for chemical modifications to enhance cellular uptake and stability. As a result, recent efforts focused on the development of small organic molecules that can correct abnormal RNA splicing event under disease conditions. This review discusses known and potential targets of these molecules, including RNA structures, trans-acting splicing factors, and the spliceosome - the macromolecular complex responsible for RNA splicing. We also rely on recent advances to discuss therapeutic applications of RNA-targeting small molecules in splicing correction. Overall, this review presents an update on strategies for RNA splicing modulation, emphasizing the therapeutic promise of small molecules.
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Affiliation(s)
- Léa Bouton
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux 146 rue Léo Saignat 33076 Bordeaux Cedex France
- Institut Européen de Chimie et de Biologie F-33600 Pessac France
| | - Agathe Ecoutin
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux 146 rue Léo Saignat 33076 Bordeaux Cedex France
- Institut Européen de Chimie et de Biologie F-33600 Pessac France
| | - Florian Malard
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux 146 rue Léo Saignat 33076 Bordeaux Cedex France
- Institut Européen de Chimie et de Biologie F-33600 Pessac France
| | - Sébastien Campagne
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux 146 rue Léo Saignat 33076 Bordeaux Cedex France
- Institut Européen de Chimie et de Biologie F-33600 Pessac France
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Beusch I, Rao B, Studer MK, Luhovska T, Šukytė V, Lei S, Oses-Prieto J, SeGraves E, Burlingame A, Jonas S, Madhani HD. Targeted high-throughput mutagenesis of the human spliceosome reveals its in vivo operating principles. Mol Cell 2023; 83:2578-2594.e9. [PMID: 37402368 PMCID: PMC10484158 DOI: 10.1016/j.molcel.2023.06.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 03/15/2023] [Accepted: 06/02/2023] [Indexed: 07/06/2023]
Abstract
The spliceosome is a staggeringly complex machine, comprising, in humans, 5 snRNAs and >150 proteins. We scaled haploid CRISPR-Cas9 base editing to target the entire human spliceosome and investigated the mutants using the U2 snRNP/SF3b inhibitor, pladienolide B. Hypersensitive substitutions define functional sites in the U1/U2-containing A complex but also in components that act as late as the second chemical step after SF3b is dissociated. Viable resistance substitutions map not only to the pladienolide B-binding site but also to the G-patch domain of SUGP1, which lacks orthologs in yeast. We used these mutants and biochemical approaches to identify the spliceosomal disassemblase DHX15/hPrp43 as the ATPase ligand for SUGP1. These and other data support a model in which SUGP1 promotes splicing fidelity by triggering early spliceosome disassembly in response to kinetic blocks. Our approach provides a template for the analysis of essential cellular machines in humans.
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Affiliation(s)
- Irene Beusch
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Beiduo Rao
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Michael K Studer
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Tetiana Luhovska
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Viktorija Šukytė
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Susan Lei
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, USA
| | - Em SeGraves
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, USA
| | - Stefanie Jonas
- Institute of Molecular Biology and Biophysics, Department of Biology, ETH Zurich, Zurich, Switzerland
| | - Hiten D Madhani
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, USA.
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Chan WC, Trieger KA, La Clair JJ, Jamieson CHM, Burkart MD. Stereochemical Control of Splice Modulation in FD-895 Analogues. J Med Chem 2023; 66:6577-6590. [PMID: 37155693 PMCID: PMC10586521 DOI: 10.1021/acs.jmedchem.2c01893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Highly functionalized skeletons of macrolide natural products gain access to rare spatial arrangements of atoms, where changes in stereochemistry can have a profound impact on the structure and function. Spliceosome modulators present a unique consensus motif, with the majority targeting a key interface within the SF3B spliceosome complex. Our recent preparative-scale synthetic campaign of 17S-FD-895 provided unique access to stereochemical analogues of this complex macrolide. Here, we report on the preparation and systematic activity evaluation of multiple FD-895 analogues. These studies examine the effects of modifications at specific stereocenters within the molecule and highlight future directions for medicinal chemical optimization of spliceosome modulators.
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Affiliation(s)
- Warren C Chan
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - Kelsey A Trieger
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - James J La Clair
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
| | - Catriona H M Jamieson
- The Division of Regenerative Medicine, Moores Cancer Center, and Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, California 92093, United States
| | - Michael D Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0358, United States
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Rozza R, Janoš P, Spinello A, Magistrato A. Role of computational and structural biology in the development of small-molecule modulators of the spliceosome. Expert Opin Drug Discov 2022; 17:1095-1109. [PMID: 35983696 DOI: 10.1080/17460441.2022.2114452] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
INTRODUCTION RNA splicing is a pivotal step of eukaryotic gene expression during which the introns are excised from the precursor (pre-)RNA and the exons are joined together to form mature RNA products (i.e a protein-coding mRNA or long non-coding (lnc)RNAs). The spliceosome, a complex ribonucleoprotein machine, performs pre-RNA splicing with extreme precision. Deregulated splicing is linked to cancer, genetic, and neurodegenerative diseases. Hence, the discovery of small-molecules targeting core spliceosome components represents an appealing therapeutic opportunity. AREA COVERED Several atomic-level structures of the spliceosome and distinct splicing-modulators bound to its protein/RNA components have been solved. Here, we review recent advances in the discovery of small-molecule splicing-modulators, discuss opportunities and challenges for their therapeutic applicability, and showcase how structural data and/or all-atom simulations can illuminate key facets of their mechanism, thus contributing to future drug-discovery campaigns. EXPERT OPINION This review highlights the potential of modulating pre-RNA splicing with small-molecules, and anticipates how the synergy of computer and wet-lab experiments will enrich our understanding of splicing regulation/deregulation mechanisms. This information will aid future structure-based drug-discovery efforts aimed to expand the currently limited portfolio of selective splicing-modulators.
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Affiliation(s)
- Riccardo Rozza
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
| | - Pavel Janoš
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
| | - Angelo Spinello
- Department of Biological, Chemical and Pharmaceutical Sciences, University of Palermo, Palermo, Italy
| | - Alessandra Magistrato
- National Research Council of Italy, Institute of Materials-foundry (CNR-IOM) C/o SISSA, Trieste, Italy
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Ye Z, Bing A, Zhao S, Yi S, Zhan X. Comprehensive analysis of spliceosome genes and their mutants across 27 cancer types in 9070 patients: clinically relevant outcomes in the context of 3P medicine. EPMA J 2022; 13:335-350. [DOI: 10.1007/s13167-022-00279-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 04/25/2022] [Indexed: 12/19/2022]
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Sellin M, Mack R, Rhodes MC, Zhang L, Berg S, Joshi K, Liu S, Wei W, S. J. PB, Larsen P, Taylor RE, Zhang J. Molecular mechanisms by which splice modulator GEX1A inhibits leukaemia development and progression. Br J Cancer 2022; 127:223-236. [PMID: 35422078 PMCID: PMC9296642 DOI: 10.1038/s41416-022-01796-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 02/18/2022] [Accepted: 03/17/2022] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION Splice modulators have been assessed clinically in treating haematologic malignancies exhibiting splice factor mutations and acute myeloid leukaemia. However, the mechanisms by which such modulators repress leukaemia remain to be elucidated. OBJECTIVES The primary goal of this assessment was to assess the molecular mechanism by which the natural splice modulator GEX1A kills leukaemic cells in vitro and within in vivo mouse models. METHODS Using human leukaemic cell lines, we assessed the overall sensitivity these cells have to GEX1A via EC50 analysis. We subsequently analysed its effects using in vivo xenograft mouse models and examined whether cell sensitivities were correlated to genetic characteristics or protein expression levels. We also utilised RT-PCR and RNAseq analyses to determine splice change and RNA expression level differences between sensitive and resistant leukaemic cell lines. RESULTS We found that, in vitro, GEX1A induced an MCL-1 isoform shift to pro-apoptotic MCL-1S in all leukaemic cell types, though sensitivity to GEX1A-induced apoptosis was negatively associated with BCL-xL expression. In BCL-2-expressing leukaemic cells, GEX1A induced BCL-2-dependent apoptosis by converting pro-survival BCL-2 into a cell killer. Thus, GEX1A + selective BCL-xL inhibition induced synergism in killing leukaemic cells, while GEX1A + BCL-2 inhibition showed antagonism in BCL-2-expressing leukaemic cells. In addition, GEX1A sensitised FLT3-ITD+ leukaemic cells to apoptosis by inducing aberrant splicing and repressing the expression of FLT3-ITD. Consistently, in in vivo xenografts, GEX1A killed the bulk of leukaemic cells via apoptosis when combined with BCL-xL inhibition. Furthermore, GEX1A repressed leukaemia development by targeting leukaemia stem cells through inhibiting FASTK mitochondrial isoform expression across sensitive and non-sensitive leukaemia types. CONCLUSION Our study suggests that GEX1A is a potent anti-leukaemic agent in combination with BCL-xL inhibitors, which targets leukaemic blasts and leukaemia stem cells through distinct mechanisms.
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Spinello A, Borišek J, Malcovati L, Magistrato A. Investigating the Molecular Mechanism of H3B-8800: A Splicing Modulator Inducing Preferential Lethality in Spliceosome-Mutant Cancers. Int J Mol Sci 2021; 22:ijms222011222. [PMID: 34681880 PMCID: PMC8540225 DOI: 10.3390/ijms222011222] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/12/2021] [Accepted: 10/14/2021] [Indexed: 11/16/2022] Open
Abstract
The SF3B1 protein, part of the SF3b complex, recognizes the intron branch point sequence of precursor messenger RNA (pre-mRNA), thus contributing to splicing fidelity. SF3B1 is frequently mutated in cancer and is the target of distinct families of splicing modulators (SMs). Among these, H3B-8800 is of particular interest, as it induces preferential lethality in cancer cells bearing the frequent and highly pathogenic K700E SF3B1 mutation. Despite the potential of H3B-8800 to treat myeloid leukemia and other cancer types hallmarked by SF3B1 mutations, the molecular mechanism underlying its preferential lethality towards spliceosome-mutant cancer cells remains elusive. Here, microsecond-long all-atom simulations addressed the binding/dissociation mechanism of H3B-8800 to wild type and K700E SF3B1-containing SF3b (K700ESB3b) complexes at the atomic level, unlocking that the K700E mutation little affects the thermodynamics and kinetic traits of H3B-8800 binding. This supports the hypothesis that the selectivity of H3B-8800 towards mutant cancer cells is unrelated to its preferential targeting of K700ESB3b. Nevertheless, this set of simulations discloses that the K700E mutation and H3B-8800 binding affect the overall SF3b internal motion, which in turn may influence the way SF3b interacts with other spliceosome components. Finally, we unveil the existence of a putative druggable SF3b pocket in the vicinity of K700E that could be harnessed in future rational drug-discovery efforts to specifically target mutant SF3b.
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Affiliation(s)
- Angelo Spinello
- National Research Council of Italy, Institute of Materials Foundry (CNR-IOM) c/o SISSA, Via Bonomea 265, 34136 Trieste, Italy;
| | - Jure Borišek
- National Institute of Chemistry, Theory Department, Hajdrihova 19, 1000 Ljubljana, Slovenia;
| | - Luca Malcovati
- Department of Hematology, IRCCS S. Matteo Hospital Foundation, 27100 Pavia, Italy;
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Alessandra Magistrato
- National Research Council of Italy, Institute of Materials Foundry (CNR-IOM) c/o SISSA, Via Bonomea 265, 34136 Trieste, Italy;
- Correspondence:
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