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Sciarrillo R, Wojtuszkiewicz A, Assaraf YG, Jansen G, Kaspers GJL, Giovannetti E, Cloos J. The role of alternative splicing in cancer: From oncogenesis to drug resistance. Drug Resist Updat 2020; 53:100728. [PMID: 33070093 DOI: 10.1016/j.drup.2020.100728] [Citation(s) in RCA: 110] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/17/2020] [Accepted: 09/21/2020] [Indexed: 12/15/2022]
Abstract
Alternative splicing is a tightly regulated process whereby non-coding sequences of pre-mRNA are removed and protein-coding segments are assembled in diverse combinations, ultimately giving rise to proteins with distinct or even opposing functions. In the past decade, whole genome/transcriptome sequencing studies revealed the high complexity of splicing regulation, which occurs co-transcriptionally and is influenced by chromatin status and mRNA modifications. Consequently, splicing profiles of both healthy and malignant cells display high diversity and alternative splicing was shown to be widely deregulated in multiple cancer types. In particular, mutations in pre-mRNA regulatory sequences, splicing regulators and chromatin modifiers, as well as differential expression of splicing factors are important contributors to cancer pathogenesis. It has become clear that these aberrations contribute to many facets of cancer, including oncogenic transformation, cancer progression, response to anticancer drug treatment as well as resistance to therapy. In this respect, alternative splicing was shown to perturb the expression a broad spectrum of relevant genes involved in drug uptake/metabolism (i.e. SLC29A1, dCK, FPGS, and TP), activation of nuclear receptor pathways (i.e. GR, AR), regulation of apoptosis (i.e. MCL1, BCL-X, and FAS) and modulation of response to immunotherapy (CD19). Furthermore, aberrant splicing constitutes an important source of novel cancer biomarkers and the spliceosome machinery represents an attractive target for a novel and rapidly expanding class of therapeutic agents. Small molecule inhibitors targeting SF3B1 or splice factor kinases were highly cytotoxic against a wide range of cancer models, including drug-resistant cells. Importantly, these effects are enhanced in specific cancer subsets, such as splicing factor-mutated and c-MYC-driven tumors. Furthermore, pre-clinical studies report synergistic effects of spliceosome modulators in combination with conventional antitumor agents. These strategies based on the use of low dose splicing modulators could shift the therapeutic window towards decreased toxicity in healthy tissues. Here we provide an extensive overview of the latest findings in the field of regulation of splicing in cancer, including molecular mechanisms by which cancer cells harness alternative splicing to drive oncogenesis and evade anticancer drug treatment as well as splicing-based vulnerabilities that can provide novel treatment opportunities. Furthermore, we discuss current challenges arising from genome-wide detection and prediction methods of aberrant splicing, as well as unravelling functional relevance of the plethora of cancer-related splicing alterations.
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Affiliation(s)
- Rocco Sciarrillo
- Department of Hematology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands; Department of Pediatric Oncology, Emma's Children's Hospital, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands; Department of Medical Oncology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Anna Wojtuszkiewicz
- Department of Hematology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Yehuda G Assaraf
- The Fred Wyszkowski Cancer Research Laboratory, Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Gerrit Jansen
- Amsterdam Immunology and Rheumatology Center, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Gertjan J L Kaspers
- Department of Pediatric Oncology, Emma's Children's Hospital, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands; Princess Máxima Center for Pediatric Oncology, Utrecht, Netherlands
| | - Elisa Giovannetti
- Department of Medical Oncology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands; Fondazione Pisana per la Scienza, Pisa, Italy
| | - Jacqueline Cloos
- Department of Hematology, Amsterdam UMC, VU University Medical Center, Cancer Center Amsterdam, Amsterdam, Netherlands.
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52
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Petasny M, Bentata M, Pawellek A, Baker M, Kay G, Salton M. Splicing to Keep Cycling: The Importance of Pre-mRNA Splicing during the Cell Cycle. Trends Genet 2020; 37:266-278. [PMID: 32950269 DOI: 10.1016/j.tig.2020.08.013] [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: 06/22/2020] [Revised: 08/09/2020] [Accepted: 08/18/2020] [Indexed: 12/16/2022]
Abstract
Pre-mRNA splicing is a fundamental process in mammalian gene expression, and alternative splicing plays an extensive role in generating protein diversity. Because the majority of genes undergo pre-mRNA splicing, most cellular processes depend on proper spliceosome function. We focus on the cell cycle and describe its dependence on pre-mRNA splicing and accurate alternative splicing. We outline the key cell-cycle factors and their known alternative splicing isoforms. We discuss different levels of pre-mRNA splicing regulation such as post-translational modifications and changes in the expression of splicing factors. We describe the effect of chromatin dynamics on pre-mRNA splicing during the cell cycle. In addition, we focus on spliceosome component SF3B1, which is mutated in many types of cancer, and describe the link between SF3B1 and its inhibitors and the cell cycle.
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Affiliation(s)
- Mayra Petasny
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mercedes Bentata
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Andrea Pawellek
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mai Baker
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gillian Kay
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, Institute for Medical Research Israel-Canada, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 91120, Israel.
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53
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Fergany AAM, Tatarskiy VV. RNA Splicing: Basic Aspects Underlie Antitumor Targeting. Recent Pat Anticancer Drug Discov 2020; 15:293-305. [PMID: 32900350 DOI: 10.2174/1574892815666200908122402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND RNA splicing, a fundamental step in gene expression, is aimed at intron removal and ordering of exons to form the protein's reading frame. OBJECTIVE This review is focused on the role of RNA splicing in cancer biology; the splicing abnormalities that lead to tumor progression emerge as targets for therapeutic intervention. METHODS We discuss the role of aberrant mRNA splicing in carcinogenesis and drug response. RESULTS AND CONCLUSION Pharmacological modulation of RNA splicing sets the stage for treatment approaches in situations where mRNA splicing is a clinically meaningful mechanism of the disease.
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Affiliation(s)
- Alzahraa A M Fergany
- Department of Occupational and Environmental Health, Graduate School of Pharmaceutical Science, Tokyo University of Science, Chiba, Japan
| | - Victor V Tatarskiy
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russian Federation
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54
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Esteve-Bruna D, Carrasco-López C, Blanco-Touriñán N, Iserte J, Calleja-Cabrera J, Perea-Resa C, Úrbez C, Carrasco P, Yanovsky MJ, Blázquez MA, Salinas J, Alabadí D. Prefoldins contribute to maintaining the levels of the spliceosome LSM2-8 complex through Hsp90 in Arabidopsis. Nucleic Acids Res 2020; 48:6280-6293. [PMID: 32396196 PMCID: PMC7293050 DOI: 10.1093/nar/gkaa354] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 02/06/2023] Open
Abstract
Although originally identified as the components of the complex aiding the cytosolic chaperonin CCT in the folding of actins and tubulins in the cytosol, prefoldins (PFDs) are emerging as novel regulators influencing gene expression in the nucleus. Work conducted mainly in yeast and animals showed that PFDs act as transcriptional regulators and participate in the nuclear proteostasis. To investigate new functions of PFDs, we performed a co-expression analysis in Arabidopsis thaliana. Results revealed co-expression between PFD and the Sm-like (LSM) genes, which encode the LSM2–8 spliceosome core complex, in this model organism. Here, we show that PFDs interact with and are required to maintain adequate levels of the LSM2–8 complex. Our data indicate that levels of the LSM8 protein, which defines and confers the functional specificity of the complex, are reduced in pfd mutants and in response to the Hsp90 inhibitor geldanamycin. We provide biochemical evidence showing that LSM8 is a client of Hsp90 and that PFD4 mediates the interaction between both proteins. Consistent with our results and with the role of the LSM2–8 complex in splicing through the stabilization of the U6 snRNA, pfd mutants showed reduced levels of this snRNA and altered pre-mRNA splicing patterns.
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Affiliation(s)
- David Esteve-Bruna
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
| | - Cristian Carrasco-López
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas "Margarita Salas" (CSIC), 28040 Madrid, Spain
| | - Noel Blanco-Touriñán
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
| | - Javier Iserte
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, CONICET, C1405BWAE Buenos Aires, Argentina
| | - Julián Calleja-Cabrera
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
| | - Carlos Perea-Resa
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas "Margarita Salas" (CSIC), 28040 Madrid, Spain
| | - Cristina Úrbez
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
| | - Pedro Carrasco
- Departament de Bioquímica i Biologia Molecular, Universitat de València, 46100 Burjassot, Spain
| | - Marcelo J Yanovsky
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, CONICET, C1405BWAE Buenos Aires, Argentina
| | - Miguel A Blázquez
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
| | - Julio Salinas
- Departamento de Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas "Margarita Salas" (CSIC), 28040 Madrid, Spain
| | - David Alabadí
- Instituto de Biología Molecular y Celular de Plantas (CSIC-Universidad Politécnica de Valencia), 46022 Valencia, Spain
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55
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Baindara P, Mandal SM. Bacteria and bacterial anticancer agents as a promising alternative for cancer therapeutics. Biochimie 2020; 177:164-189. [PMID: 32827604 DOI: 10.1016/j.biochi.2020.07.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/04/2020] [Accepted: 07/31/2020] [Indexed: 12/20/2022]
Abstract
Cancer is the leading cause of deaths worldwide, though significant advances have occurred in its diagnosis and treatment. The development of resistance against chemotherapeutic agents, their side effects, and non-specific toxicity urge to screen for the novel anticancer agent. Hence, the development of novel anticancer agents with a new mechanism of action has become a major scientific challenge. Bacteria and bacterially produced bioactive compounds have recently emerged as a promising alternative for cancer therapeutics. Bacterial anticancer agents such as antibiotics, bacteriocins, non-ribosomal peptides, polyketides, toxins, etc. These are adopted different mechanisms of actions such as apoptosis, necrosis, reduced angiogenesis, inhibition of translation and splicing, and obstructing essential signaling pathways to kill cancer cells. Also, live tumor-targeting bacteria provided a unique therapeutic alternative for cancer treatment. This review summarizes the anticancer properties and mechanism of actions of the anticancer agents of bacterial origin and antitumor bacteria along with their possible future applications in cancer therapeutics.
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Affiliation(s)
- Piyush Baindara
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, 65212, USA.
| | - Santi M Mandal
- Central Research Facility, Indian Institute of Technology Kharagpur, Kharagpur, 721302, WB, India.
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56
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Shi Y, Bray W, Smith AJ, Zhou W, Calaoagan J, Lagisetti C, Sambucetti L, Crews P, Lokey RS, Webb TR. An exon skipping screen identifies antitumor drugs that are potent modulators of pre-mRNA splicing, suggesting new therapeutic applications. PLoS One 2020; 15:e0233672. [PMID: 32469945 PMCID: PMC7259758 DOI: 10.1371/journal.pone.0233672] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 05/11/2020] [Indexed: 02/07/2023] Open
Abstract
Agents that modulate pre-mRNA splicing are of interest in multiple therapeutic areas, including cancer. We report our recent screening results with the application of a cell-based Triple Exon Skipping Luciferase Reporter (TESLR) using a library that is composed of FDA approved drugs, clinical compounds, and mechanistically characterized tool compounds. Confirmatory assays showed that three clinical antitumor therapeutic candidates (milciclib, PF-3758309 and PF-562271) are potent splicing modulators and that these drugs are, in fact, nanomolar inhibitors of multiple kinases involved in the regulation the spliceosome. We also report the identification of new SF3B1 antagonists (sudemycinol C and E) and show that these antagonists can be used to develop a displacement assay for SF3B1 small molecule ligands. These results further support the broad potential for the development of agents that target the spliceosome for the treatment of cancer and other diseases, as well as new avenues for the discovery of new chemotherapeutic agents for a range of diseases.
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Affiliation(s)
- Yihui Shi
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
| | - Walter Bray
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, United States of America
| | - Alexander J. Smith
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, United States of America
| | - Wei Zhou
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
| | - Joy Calaoagan
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
| | - Chandraiah Lagisetti
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
| | - Lidia Sambucetti
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
| | - Phillip Crews
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, United States of America
| | - R. Scott Lokey
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, United States of America
| | - Thomas R. Webb
- Bioscience Division, SRI International, Menlo Park, CA, United States of America
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, United States of America
- * E-mail:
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57
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Sebbag-Sznajder N, Brody Y, Hochberg-Laufer H, Shav-Tal Y, Sperling J, Sperling R. Dynamic Supraspliceosomes Are Assembled on Different Transcripts Regardless of Their Intron Number and Splicing State. Front Genet 2020; 11:409. [PMID: 32499811 PMCID: PMC7243799 DOI: 10.3389/fgene.2020.00409] [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: 09/16/2019] [Accepted: 03/31/2020] [Indexed: 11/13/2022] Open
Abstract
Splicing and alternative splicing of pre-mRNA are key sources in the formation of diversity in the human proteome. These processes have a central role in the regulation of the gene expression pathway. Yet, how spliceosomes are assembled on a multi-intronic pre-mRNA is at present not well understood. To study the spliceosomes assembled in vivo on transcripts with variable number of introns, we examined a series of three related transcripts derived from the β-globin gene, where two transcript types contained increasing number of introns, while one had only an exon. Each transcript had multiple MS2 sequence repeats that can be bound by the MS2 coat protein. Using our protocol for isolation of endogenous spliceosomes under native conditions from cell nuclei, we show that all three transcripts are found in supraspliceosomes – 21 MDa dynamic complexes, sedimenting at 200S in glycerol gradients, and composed of four native spliceosomes connected by the transcript. Affinity purification of complexes assembled on the transcript with most introns (termed E6), using the MS2 tag, confirmed the assembly of E6 in supraspliceosomes with components such as Sm proteins and PSF. Furthermore, splicing inhibition by spliceostatin A did not inhibit the assembly of supraspliceosomes on the E6 transcript, yet increased the percentage of E6 pre-mRNA supraspliceosomes. These findings were corroborated in intact cells, using RNA FISH to detect the MS2-tagged E6 mRNA, together with GFP-tagged splicing factors, showing the assembly of splicing factors SRSF2, U1-70K, and PRP8 onto the E6 transcripts under normal conditions and also when splicing was inhibited. This study shows that different transcripts with different number of introns, or lacking an intron, are assembled in supraspliceosomes even when splicing is inhibited. This assembly starts at the site of transcription and can continue during the life of the transcript in the nucleoplasm. This study further confirms the dynamic and universal nature of supraspliceosomes that package RNA polymerase II transcribed pre-mRNAs into complexes composed of four native spliceosomes connected by the transcript, independent of their length, number of introns, or splicing state.
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Affiliation(s)
| | - Yehuda Brody
- The Mina and Everard Goodman Faculty of Life Sciences and The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
| | - Hodaya Hochberg-Laufer
- The Mina and Everard Goodman Faculty of Life Sciences and The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
| | - Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences and The Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan, Israel
| | - Joseph Sperling
- Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot, Israel
| | - Ruth Sperling
- Department of Genetics, The Hebrew University of Jerusalem, Jerusalem, Israel
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58
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Eymin B. Targeting the spliceosome machinery: A new therapeutic axis in cancer? Biochem Pharmacol 2020; 189:114039. [PMID: 32417188 DOI: 10.1016/j.bcp.2020.114039] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/12/2020] [Indexed: 02/06/2023]
Abstract
Pre-mRNA splicing is the removal of introns and ligation of exons to form mature mRNAs, and it provides a critical mechanism by which eukaryotic cells can regulate their gene expression. Strikingly, more than 90% of protein-encoding transcripts are alternatively spliced, through exon inclusion/skipping, differential use of 5' or 3' alternative splice sites, intron retention or selection of an alternative promoter, thereby drastically increasing protein diversity. Splicing is altered in various pathological conditions, including cancers. In the last decade, high-throughput transcriptomic analyses have identified thousands of splice variants in cancers, which can distinguish between tumoral and normal tissues as well as identify tumor types, subtypes and clinical stages. These abnormal or aberrantly expressed splice variants, found in all cancer hallmarks, can result from mutations in splice sites, deregulated expression or even somatic mutations of components of the spliceosome machinery. Therefore, and based on these recent observations, a new anti-cancer strategy of targeting the spliceosome machinery with small molecules has emerged; however, the potential for these therapies is still a matter of great debate. Notably, more preclinical studies are needed to clarify which splicing patterns are mainly affected by these compounds, which cancer patients could be the most eligible for these treatments and whether using these spliceosome inhibitors alone or in combination with chemotherapies or targeted therapies would provide better therapeutic benefits. In this commentary, I will discuss all of these aspects.
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Affiliation(s)
- Beatrice Eymin
- INSERM U1209, CNRS UMR5309, Institute For Advanced Biosciences, 38000 Grenoble, France; Université Grenoble Alpes, 38000 Grenoble, France.
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59
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Tavanez JP, Caetano R, Branco C, Brito IM, Miragaia-Pereira A, Vassilevskaia T, Quina AS, Cunha C. Hepatitis delta virus interacts with splicing factor SF3B155 and alters pre-mRNA splicing of cell cycle control genes. FEBS J 2020; 287:3719-3732. [PMID: 32352217 DOI: 10.1111/febs.15352] [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: 09/23/2019] [Revised: 12/14/2019] [Accepted: 04/28/2020] [Indexed: 11/28/2022]
Abstract
Hepatitis delta virus (HDV) is the agent responsible for the most severe form of human viral hepatitis. The HDV genome consists of a single-stranded circular RNA molecule that encodes for one single protein, the delta antigen. Given its simplicity, HDV must make use of several host cellular proteins to accomplish its life cycle processes, including transcription, replication, post-transcriptional, and post-translational modifications. Consequently, identification of the interactions established between HDV components and host proteins assumes a pivotal interest in the search of novel therapeutic targets. Here, we used the yeast three-hybrid system to screen a human liver cDNA library to identify host proteins that interact with the HDV genomic RNA. One of the identified proteins corresponded to the splicing factor SF3B155, a component of the U2snRNP complex that is essential for the early recognition of 3' splice sites in the pre-mRNAs of human genes. We show that the interaction between the HDV genomic RNA and SF3B155 occurs in vivo and that the expression of HDV promotes changes in splicing of human genes whose alternative splicing is SF3B155-dependent. We further show that expression of HDV triggers alterations in several constitutive and alternative splicing events in the tumor suppressor RBM5 transcript, with consequent reduction of its protein levels. This is the first description that HDV expression promotes changes in the splicing of human genes, and we suggest that the HDV-induced alternative splicing changes, through SF3B155 sequester, may contribute for the early progression to hepatocellular carcinoma characteristic of HDV-infected patients.
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Affiliation(s)
- João Paulo Tavanez
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Rafael Caetano
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Cristina Branco
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Inês Margarida Brito
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Ana Miragaia-Pereira
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Tatiana Vassilevskaia
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
| | - Ana Sofia Quina
- CESAM - Centre for Environmental and Marine Studies, Universidade de Aveiro, Portugal.,Faculdade de Ciências da Universidade de Lisboa, Portugal
| | - Celso Cunha
- Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade NOVA de Lisboa (UNL), Portugal
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60
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Prieto C, Kharas MG. RNA Regulators in Leukemia and Lymphoma. Cold Spring Harb Perspect Med 2020; 10:cshperspect.a034967. [PMID: 31615866 DOI: 10.1101/cshperspect.a034967] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Posttranscriptional regulation of mRNA is a powerful and tightly controlled process in which cells command the integrity, diversity, and abundance of their protein products. RNA-binding proteins (RBPs) are the principal players that control many intermediary steps of posttranscriptional regulation. Recent advances in this field have discovered the importance of RBPs in hematological diseases. Herein we will review a number of RBPs that have been determined to play critical functions in leukemia and lymphoma. Furthermore, we will discuss the potential therapeutic strategies that are currently being studied to specifically target RBPs in these diseases.
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Affiliation(s)
- Camila Prieto
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
| | - Michael G Kharas
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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61
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Kaur H, Groubert B, Paulson JC, McMillan S, Hoskins AA. Impact of cancer-associated mutations in Hsh155/SF3b1 HEAT repeats 9-12 on pre-mRNA splicing in Saccharomyces cerevisiae. PLoS One 2020; 15:e0229315. [PMID: 32320410 PMCID: PMC7176370 DOI: 10.1371/journal.pone.0229315] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 03/20/2020] [Indexed: 11/22/2022] Open
Abstract
Mutations in the splicing machinery have been implicated in a number of human diseases. Most notably, the U2 small nuclear ribonucleoprotein (snRNP) component SF3b1 has been found to be frequently mutated in blood cancers such as myelodysplastic syndromes (MDS). SF3b1 is a highly conserved HEAT repeat (HR)-containing protein and most of these blood cancer mutations cluster in a hot spot located in HR4-8. Recently, a second mutational hotspot has been identified in SF3b1 located in HR9-12 and is associated with acute myeloid leukemias, bladder urothelial carcinomas, and uterine corpus endometrial carcinomas. The consequences of these mutations on SF3b1 functions during splicing have not yet been tested. We incorporated the corresponding mutations into the yeast homolog of SF3b1 and tested their impact on splicing. We find that all of these HR9-12 mutations can support splicing in yeast, and this suggests that none of them are loss of function alleles in humans. The Hsh155V502F mutation alters splicing of several pre-mRNA reporters containing weak branch sites as well as a genetic interaction with Prp2 and physical interactions with Prp5 and Prp3. The ability of a single allele of Hsh155 to perturb interactions with multiple factors functioning at different stages of the splicing reaction suggests that some SF3b1-mutant disease phenotypes may have a complex origin on the spliceosome.
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Affiliation(s)
- Harpreet Kaur
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Brent Groubert
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Joshua C. Paulson
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Sarah McMillan
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Aaron A. Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Integrated Program in Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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62
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Roles and mechanisms of alternative splicing in cancer - implications for care. Nat Rev Clin Oncol 2020; 17:457-474. [PMID: 32303702 DOI: 10.1038/s41571-020-0350-x] [Citation(s) in RCA: 360] [Impact Index Per Article: 90.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2020] [Indexed: 12/14/2022]
Abstract
Removal of introns from messenger RNA precursors (pre-mRNA splicing) is an essential step for the expression of most eukaryotic genes. Alternative splicing enables the regulated generation of multiple mRNA and protein products from a single gene. Cancer cells have general as well as cancer type-specific and subtype-specific alterations in the splicing process that can have prognostic value and contribute to every hallmark of cancer progression, including cancer immune responses. These splicing alterations are often linked to the occurrence of cancer driver mutations in genes encoding either core components or regulators of the splicing machinery. Of therapeutic relevance, the transcriptomic landscape of cancer cells makes them particularly vulnerable to pharmacological inhibition of splicing. Small-molecule splicing modulators are currently in clinical trials and, in addition to splice site-switching antisense oligonucleotides, offer the promise of novel and personalized approaches to cancer treatment.
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63
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Fujita KI, Ishizuka T, Mitsukawa M, Kurata M, Masuda S. Regulating Divergent Transcriptomes through mRNA Splicing and Its Modulation Using Various Small Compounds. Int J Mol Sci 2020; 21:ijms21062026. [PMID: 32188117 PMCID: PMC7139312 DOI: 10.3390/ijms21062026] [Citation(s) in RCA: 5] [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: 02/14/2020] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 12/14/2022] Open
Abstract
Human transcriptomes are more divergent than genes and contribute to the sophistication of life. This divergence is derived from various isoforms arising from alternative splicing. In addition, alternative splicing regulated by spliceosomal factors and RNA structures, such as the RNA G-quadruplex, is important not only for isoform diversity but also for regulating gene expression. Therefore, abnormal splicing leads to serious diseases such as cancer and neurodegenerative disorders. In the first part of this review, we describe the regulation of divergent transcriptomes using alternative mRNA splicing. In the second part, we present the relationship between the disruption of splicing and diseases. Recently, various compounds with splicing inhibitor activity were established. These splicing inhibitors are recognized as a biological tool to investigate the molecular mechanism of splicing and as a potential therapeutic agent for cancer treatment. Food-derived compounds with similar functions were found and are expected to exhibit anticancer effects. In the final part, we describe the compounds that modulate the messenger RNA (mRNA) splicing process and their availability for basic research and future clinical potential.
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64
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Bressin RK, Osman S, Pohorilets I, Basu U, Koide K. Total Synthesis of Meayamycin B. J Org Chem 2020; 85:4637-4647. [DOI: 10.1021/acs.joc.9b03370] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- Robert K. Bressin
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Sami Osman
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Ivanna Pohorilets
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Upamanyu Basu
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Kazunori Koide
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, United States
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65
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Human Cancer-Associated Mutations of SF3B1 Lead to a Splicing Modification of Its Own RNA. Cancers (Basel) 2020; 12:cancers12030652. [PMID: 32168916 PMCID: PMC7139785 DOI: 10.3390/cancers12030652] [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: 02/11/2020] [Revised: 03/02/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023] Open
Abstract
Deregulation of pre-mRNA splicing is observed in many cancers and hematological malignancies. Genes encoding splicing factors are frequently mutated in myelodysplastic syndromes, in which SF3B1 mutations are the most frequent. SF3B1 is an essential component of the U2 small nuclear ribonucleoprotein particle that interacts with branch point sequences close to the 3’ splice site during pre-mRNA splicing. SF3B1 mutations mostly lead to substitutions at restricted sites in the highly conserved HEAT domain, causing a modification of its function. We found that SF3B1 was aberrantly spliced in various neoplasms carrying an SF3B1 mutation, by exploring publicly available RNA sequencing raw data. We aimed to characterize this novel SF3B1 transcript, which is expected to encode a protein with an insertion of eight amino acids in the H3 repeat of the HEAT domain. We investigated the splicing proficiency of this SF3B1 protein isoform, in association with the most frequent mutation (K700E), through functional complementation assays in two myeloid cell lines stably expressing distinct SF3B1 variants. The yeast Schizosaccharomyces pombe was also used as an alternative model. Insertion of these eight amino acids in wild-type or mutant SF3B1 (K700E) abolished SF3B1 essential function, highlighting the crucial role of the H3 repeat in the splicing function of SF3B1.
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66
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Sun C. The SF3b complex: splicing and beyond. Cell Mol Life Sci 2020; 77:3583-3595. [PMID: 32140746 PMCID: PMC7452928 DOI: 10.1007/s00018-020-03493-z] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/13/2020] [Accepted: 02/20/2020] [Indexed: 12/17/2022]
Abstract
The SF3b complex is an intrinsic component of the functional U2 small nuclear ribonucleoprotein (snRNP). As U2 snRNP enters nuclear pre-mRNA splicing, SF3b plays key roles in recognizing the branch point sequence (BPS) and facilitating spliceosome assembly and activation. Since the discovery of SF3b, substantial progress has been made in elucidating its molecular mechanism during splicing. In addition, numerous recent studies indicate that SF3b and its components are engaged in various molecular and cellular events that are beyond the canonical role in splicing. This review summarizes the current knowledge on the SF3b complex and highlights its multiple roles in splicing and beyond.
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Affiliation(s)
- Chengfu Sun
- Non-coding RNA and Drug Discovery Key Laboratory of Sichuan Province, Chengdu Medical College, Chengdu, 610500, China.
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67
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Dong X, Chen R. Understanding aberrant RNA splicing to facilitate cancer diagnosis and therapy. Oncogene 2019; 39:2231-2242. [PMID: 31819165 DOI: 10.1038/s41388-019-1138-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/22/2019] [Accepted: 11/27/2019] [Indexed: 12/31/2022]
Abstract
Almost all genes in normal cells undergo alternative RNA splicing to generate a greater extent of diversification of gene products for normal cellular functions. RNA splicing is tightly regulated and closely interplays with genetic and epigenetic machinery. While DNA polymorphism and somatic mutations modulate alternative splicing patterns, RNA splicing also controls genomic stability, chromatin organization, and transcriptome. Tumor cells, in turn, often take advantage of aberrant RNA splicing to develop, grow and progress into therapy-resistant tumors. Understanding alternative RNA splicing in tumor cells would, therefore, provide us opportunities to gain further insights into tumor biology, identify diagnostic or prognosis biomarkers, as well as to design effective therapeutic means to control tumor progression. Here, we provide an overview of RNA splicing mechanisms and use prostate cancer as an example to review recent advancements in our understanding of RNA splicing in cancer progression and therapy resistance. We also discuss emerging diagnostic and therapeutic potentials of RNA splicing events or RNA splicing factors.
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Affiliation(s)
- Xuesen Dong
- Department of Urologic Sciences, Faculty of Medicine, The University of British Columbia, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada. .,The Vancouver Prostate Centre, Vancouver General Hospital, 2660 Oak Street, Vancouver, BC, V6H 3Z6, Canada.
| | - Ruiqi Chen
- Faculty of Medicine, University of Toronto, 27 King's College Circle 8, Toronto, ON, M5S 1A1, Canada
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68
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Taylor J, Lee SC. Mutations in spliceosome genes and therapeutic opportunities in myeloid malignancies. Genes Chromosomes Cancer 2019; 58:889-902. [PMID: 31334570 PMCID: PMC6852509 DOI: 10.1002/gcc.22784] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of RNA splicing more than 40 years ago, our comprehension of the molecular events orchestrating constitutive and alternative splicing has greatly improved. Dysregulation of pre-mRNA splicing has been observed in many human diseases including neurodegenerative diseases and cancer. The recent identification of frequent somatic mutations in core components of the spliceosome in myeloid malignancies and functional analysis using model systems has advanced our knowledge of how splicing alterations contribute to disease pathogenesis. In this review, we summarize our current understanding on the mechanisms of how mutant splicing factors impact splicing and the resulting functional and pathophysiological consequences. We also review recent advances to develop novel therapeutic approaches targeting splicing catalysis and splicing regulatory proteins, and discuss emerging technologies using oligonucleotide-based therapies to modulate pathogenically spliced isoforms.
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Affiliation(s)
- Justin Taylor
- Human Oncology and Pathogenesis ProgramMemorial Sloan Kettering Cancer CenterNew YorkNew York
- Leukemia Service, Department of MedicineMemorial Sloan Kettering Cancer CenterNew YorkNew York
| | - Stanley C. Lee
- Human Oncology and Pathogenesis ProgramMemorial Sloan Kettering Cancer CenterNew YorkNew York
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69
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van der Feltz C, Hoskins AA. Structural and functional modularity of the U2 snRNP in pre-mRNA splicing. Crit Rev Biochem Mol Biol 2019; 54:443-465. [PMID: 31744343 DOI: 10.1080/10409238.2019.1691497] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The U2 small nuclear ribonucleoprotein (snRNP) is an essential component of the spliceosome, the cellular machine responsible for removing introns from precursor mRNAs (pre-mRNAs) in all eukaryotes. U2 is an extraordinarily dynamic splicing factor and the most frequently mutated in cancers. Cryo-electron microscopy (cryo-EM) has transformed our structural and functional understanding of the role of U2 in splicing. In this review, we synthesize these and other data with respect to a view of U2 as an assembly of interconnected functional modules. These modules are organized by the U2 small nuclear RNA (snRNA) for roles in spliceosome assembly, intron substrate recognition, and protein scaffolding. We describe new discoveries regarding the structure of U2 components and how the snRNP undergoes numerous conformational and compositional changes during splicing. We specifically highlight large scale movements of U2 modules as the spliceosome creates and rearranges its active site. U2 serves as a compelling example for how cellular machines can exploit the modular organization and structural plasticity of an RNP.
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Affiliation(s)
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
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70
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Affiliation(s)
- Barla Thirupathi
- Department of Chemical ScienceIndian Institute of Science Education and Research BerhampurTransit Campus, Govt. ITI Building, NH 59 Engineering School Road, Ganjam Berhampur 760 010, Odisha India
| | - Mahesh Kumar Zilla
- Department of Chemical ScienceIndian Institute of Science Education and Research BerhampurTransit Campus, Govt. ITI Building, NH 59 Engineering School Road, Ganjam Berhampur 760 010, Odisha India
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71
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Desterro J, Bak-Gordon P, Carmo-Fonseca M. Targeting mRNA processing as an anticancer strategy. Nat Rev Drug Discov 2019; 19:112-129. [PMID: 31554928 DOI: 10.1038/s41573-019-0042-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2019] [Indexed: 12/19/2022]
Abstract
Discoveries in the past decade have highlighted the potential of mRNA as a therapeutic target for cancer. Specifically, RNA sequencing revealed that, in addition to gene mutations, alterations in mRNA can contribute to the initiation and progression of cancer. Indeed, precursor mRNA processing, which includes the removal of introns by splicing and the formation of 3' ends by cleavage and polyadenylation, is frequently altered in tumours. These alterations result in numerous cancer-specific mRNAs that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumour-suppressor genes. Abnormally spliced and polyadenylated mRNAs are also associated with resistance to cancer treatment and, unexpectedly, certain cancers are highly sensitive to the pharmacological inhibition of splicing. This Review summarizes recent progress in our understanding of how splicing and polyadenylation are altered in cancer and highlights how this knowledge has been translated for drug discovery, resulting in the production of small molecules and oligonucleotides that modulate the spliceosome and are in clinical trials for the treatment of cancer.
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Affiliation(s)
- Joana Desterro
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto Português de Oncologia de Lisboa, Serviço de Hematologia, Lisboa, Portugal
| | - Pedro Bak-Gordon
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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72
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Chen H, Bian Z, Ravichandran V, Li R, Sun Y, Huo L, Fu J, Bian X, Xia L, Tu Q, Zhang Y. Biosynthesis of polyketides by trans-AT polyketide synthases in Burkholderiales. Crit Rev Microbiol 2019; 45:162-181. [PMID: 31218924 DOI: 10.1080/1040841x.2018.1514365] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Widely used as drugs and agrochemicals, polyketides are a family of bioactive natural products, with diverse structures and functions. Polyketides are produced by megaenzymes termed as polyketide synthases (PKSs). PKS biosynthetic pathways are divided into the cis-AT PKSs and trans-AT PKSs; a division based mainly on the absence of an acyltransferase (AT) domain in the trans-AT PKS modules. In trans-AT biosynthesis, the AT activity is contributed via one or several independent proteins, and there are few other characteristics that distinguish trans-AT PKSs from cis-AT PKSs, especially in the formation of the β-branch. The trans-AT PKSs constitute a major PKS pathway, and many are found in Burkholderia species, which are prevalent in the environment and prolific sources of polyketides. This review summarizes studies from 1973 to 2017 on the biosynthesis of natural products by trans-AT PKSs from Burkholderia species.
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Affiliation(s)
- Hanna Chen
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China.,b State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory of Microbial Molecular Biology, College of Life Science , Hunan Normal University , Changsha , People's Republic of China
| | - Zhilong Bian
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Vinothkannan Ravichandran
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Ruijuan Li
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Yi Sun
- c Institute of Chinese Materia Medica , China Academy of Chinese Medical Sciences , Beijing , People's Republic of China
| | - Liujie Huo
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Jun Fu
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Xiaoying Bian
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Liqiu Xia
- b State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory of Microbial Molecular Biology, College of Life Science , Hunan Normal University , Changsha , People's Republic of China
| | - Qiang Tu
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China
| | - Youming Zhang
- a Shandong University-Helmholtz Institute of Biotechnology, State Key Laboratory of Microbial Technology, School of Life Sciences , Shandong University , Qingdao , People's Republic of China.,b State Key Laboratory of Developmental Biology of Freshwater Fish, Hunan Provincial Key Laboratory of Microbial Molecular Biology, College of Life Science , Hunan Normal University , Changsha , People's Republic of China
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73
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Coltri PP, Dos Santos MGP, da Silva GHG. Splicing and cancer: Challenges and opportunities. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 10:e1527. [PMID: 30773852 DOI: 10.1002/wrna.1527] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/14/2018] [Accepted: 01/17/2019] [Indexed: 12/11/2022]
Abstract
Cancer arises from alterations in several metabolic processes affecting proliferation, growth, replication and death of cells. A fundamental challenge in the study of cancer biology is to uncover molecular mechanisms that lead to malignant cellular transformation. Recent genomic analyses revealed that many molecular alterations observed in cancers come from modifications in the splicing process, including mutations in pre-mRNA regulatory sequences, mutations in spliceosome components, and altered ratio of specific splicing regulators. While alterations in splice site preferences might generate alternative isoforms enabling different biological functions, these might also be responsible for nonfunctional isoforms that can eventually cause dysregulation in cellular processes. Molecular characteristics of regulatory sequences and proteins might also be important prognostic tools revealing a cancer-specific splicing pattern and linking splicing control to cancer development. The connection between cancer biology and splicing regulation is of primary importance to understand the mechanisms leading to disease and also to improve development of therapeutic approaches. Splicing modulation is being explored in new anti-cancer therapies and further investigation of targeted splicing factors is critical for the success of these strategies. This article is categorized under: RNA Processing > Splicing Mechanisms RNA-Based Catalysis > RNA Catalysis in Splicing and Translation RNA Processing > Splicing Regulation/Alternative Splicing RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Patricia P Coltri
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Maria G P Dos Santos
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
| | - Guilherme H G da Silva
- Department of Cell and Developmental Biology, Institute for Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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74
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Loerch S, Leach JR, Horner SW, Maji D, Jenkins JL, Pulvino MJ, Kielkopf CL. The pre-mRNA splicing and transcription factor Tat-SF1 is a functional partner of the spliceosome SF3b1 subunit via a U2AF homology motif interface. J Biol Chem 2018; 294:2892-2902. [PMID: 30567737 DOI: 10.1074/jbc.ra118.006764] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/10/2018] [Indexed: 01/09/2023] Open
Abstract
The transcription elongation and pre-mRNA splicing factor Tat-SF1 associates with the U2 small nuclear ribonucleoprotein (snRNP) of the spliceosome. However, the direct binding partner and underlying interactions mediating the Tat-SF1-U2 snRNP association remain unknown. Here, we identified SF3b1 as a Tat-SF1-interacting subunit of the U2 snRNP. Our 1.1 Å resolution crystal structure revealed that Tat-SF1 contains a U2AF homology motif (UHM) protein-protein interaction module. We demonstrated that Tat-SF1 preferentially and directly binds the SF3b1 subunit compared with other U2AF ligand motif (ULM)-containing splicing factors, and further established that SF3b1 association depends on the integrity of the Tat-SF1 UHM. We next compared the Tat-SF1-binding affinities for each of the five known SF3b1 ULMs and then determined the structures of representative high- and low-affinity SF3b1 ULM complexes with the Tat-SF1 UHM at 1.9 Å and 2.1 Å resolutions, respectively. These structures revealed a canonical UHM-ULM interface, comprising a Tat-SF1 binding pocket for a ULM tryptophan (SF3b1 Trp338) and electrostatic interactions with a basic ULM tail. Importantly, we found that SF3b1 regulates Tat-SF1 levels and that these two factors influence expression of overlapping representative transcripts, consistent with a functional partnership of Tat-SF1 and SF3b1. Altogether, these results define a new molecular interface of the Tat-SF1-U2 snRNP complex for gene regulation.
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Affiliation(s)
- Sarah Loerch
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Justin R Leach
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Steven W Horner
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Debanjana Maji
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Jermaine L Jenkins
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Mary J Pulvino
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
| | - Clara L Kielkopf
- From the Center for RNA Biology, Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642
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75
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Di C, Syafrizayanti, Zhang Q, Chen Y, Wang Y, Zhang X, Liu Y, Sun C, Zhang H, Hoheisel JD. Function, clinical application, and strategies of Pre-mRNA splicing in cancer. Cell Death Differ 2018; 26:1181-1194. [PMID: 30464224 PMCID: PMC6748147 DOI: 10.1038/s41418-018-0231-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/09/2018] [Accepted: 10/23/2018] [Indexed: 12/22/2022] Open
Abstract
Pre-mRNA splicing is a fundamental process that plays a considerable role in generating protein diversity. Pre-mRNA splicing is also the key to the pathology of numerous diseases, especially cancers. In this review, we discuss how aberrant splicing isoforms precisely regulate three basic functional aspects in cancer: proliferation, metastasis and apoptosis. Importantly, clinical function of aberrant splicing isoforms is also discussed, in particular concerning drug resistance and radiosensitivity. Furthermore, this review discusses emerging strategies how to modulate pathologic aberrant splicing isoforms, which are attractive, novel therapeutic agents in cancer. Last we outline current and future directions of isoforms diagnostic methodologies reported so far in cancer. Thus, it is highlighting significance of aberrant splicing isoforms as markers for cancer and as targets for cancer therapy.
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Affiliation(s)
- Cuixia Di
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Syafrizayanti
- Division of Functional Genome Analysis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120, Heidelberg, Germany.,Department of Chemistry, Faculty of Mathematics and Natural Sciences, Andalas University, Kampus Limau Manis, Padang, Indonesia
| | - Qianjing Zhang
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yuhong Chen
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yupei Wang
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xuetian Zhang
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yang Liu
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China
| | - Chao Sun
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China.,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China
| | - Hong Zhang
- Department of Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, China. .,Key Laboratory of Heavy Ion Radiation Biology and Medicine of Chinese Academy of Sciences, 730000, Lanzhou, China.
| | - Jörg D Hoheisel
- Division of Functional Genome Analysis, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 580, 69120, Heidelberg, Germany.
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76
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Pianigiani G, Licastro D, Fortugno P, Castiglia D, Petrovic I, Pagani F. Microprocessor-dependent processing of splice site overlapping microRNA exons does not result in changes in alternative splicing. RNA (NEW YORK, N.Y.) 2018; 24:1158-1171. [PMID: 29895677 PMCID: PMC6097652 DOI: 10.1261/rna.063438.117] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 06/08/2018] [Indexed: 05/20/2023]
Abstract
MicroRNAs are found throughout the genome and are processed by the microprocessor complex (MPC) from longer precursors. Some precursor miRNAs overlap intron:exon junctions. These splice site overlapping microRNAs (SO-miRNAs) are mostly located in coding genes. It has been intimated, in the rarer examples of SO-miRNAs in noncoding RNAs, that the competition between the spliceosome and the MPC modulates alternative splicing. However, the effect of this overlap on coding transcripts is unknown. Unexpectedly, we show that neither Drosha silencing nor SF3b1 silencing changed the inclusion ratio of SO-miRNA exons. Two SO-miRNAs, located in genes that code for basal membrane proteins, are known to inhibit proliferation in primary keratinocytes. These SO-miRNAs were up-regulated during differentiation and the host mRNAs were down-regulated, but again there was no change in inclusion ratio of the SO-miRNA exons. Interestingly, Drosha silencing increased nascent RNA density, on chromatin, downstream from SO-miRNA exons. Overall our data suggest a novel mechanism for regulating gene expression in which MPC-dependent cleavage of SO-miRNA exons could cause premature transcriptional termination of coding genes rather than affecting alternative splicing.
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Affiliation(s)
- Giulia Pianigiani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Danilo Licastro
- CBM S.c.r.l., Area Science Park, Basovizza, 34149 Trieste, Italy
| | - Paola Fortugno
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata (IDI)-IRCCS, 00167 Rome, Italy
| | - Daniele Castiglia
- Laboratory of Molecular and Cell Biology, Istituto Dermopatico dell'Immacolata (IDI)-IRCCS, 00167 Rome, Italy
| | - Ivana Petrovic
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Franco Pagani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
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77
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Alvelos MI, Juan-Mateu J, Colli ML, Turatsinze JV, Eizirik DL. When one becomes many-Alternative splicing in β-cell function and failure. Diabetes Obes Metab 2018; 20 Suppl 2:77-87. [PMID: 30230174 PMCID: PMC6148369 DOI: 10.1111/dom.13388] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 05/22/2018] [Accepted: 05/30/2018] [Indexed: 12/20/2022]
Abstract
Pancreatic β-cell dysfunction and death are determinant events in type 1 diabetes (T1D), but the molecular mechanisms behind β-cell fate remain poorly understood. Alternative splicing is a post-transcriptional mechanism by which a single gene generates different mRNA and protein isoforms, expanding the transcriptome complexity and enhancing protein diversity. Neuron-specific and certain serine/arginine-rich RNA binding proteins (RBP) are enriched in β-cells, playing crucial roles in the regulation of insulin secretion and β-cell survival. Moreover, alternative exon networks, regulated by inflammation or diabetes susceptibility genes, control key pathways and processes for the correct function and survival of β-cells. The challenge ahead of us is to understand the precise role of alternative splicing regulators and splice variants on β-cell function, dysfunction and death and develop tools to modulate it.
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Affiliation(s)
- Maria Inês Alvelos
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Jonàs Juan-Mateu
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Maikel Luis Colli
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Jean-Valéry Turatsinze
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
| | - Décio L. Eizirik
- ULB Center for Diabetes Research and Welbio, Medical Faculty, Université Libre de Bruxelles (ULB), Route de Lennik, 808 – CP618, B-1070 Brussels, Belgium
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78
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Carrocci TJ, Paulson JC, Hoskins AA. Functional analysis of Hsh155/SF3b1 interactions with the U2 snRNA/branch site duplex. RNA (NEW YORK, N.Y.) 2018; 24:1028-1040. [PMID: 29752352 PMCID: PMC6049509 DOI: 10.1261/rna.065664.118] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/10/2018] [Indexed: 05/25/2023]
Abstract
SF3b1 is an essential component of the U2 snRNP implicated in branch site (BS) recognition and found to be frequently mutated in several human cancers. While recent structures of yeast and human SF3b1 have revealed its molecular architecture, the importance of specific RNA:protein contacts and conformational changes remains largely uncharacterized. Here, we performed mutational analysis of yeast SF3b1, guided by recent structures of the spliceosome. We find that conserved amino acids contacting the U2 snRNA backbone of the U2/BS duplex are nonessential, and that yeast can tolerate truncation of the HEAT repeats containing these amino acids. The pocket housing the branchpoint adenosine (BP-A) is also amenable to mutation despite strong conservation. However, mutations that support viability can still lead to defects in splicing pre-mRNAs with nonconsensus BS substitutions found at -3, -2, -1, and +1 positions relative to the BP-A or at the branchpoint position. Through the generation of yeast and human chimeric proteins, we further defined the functionally conserved regions of Hsh155 as well as identify changes in BS usage resulting from inclusion of human SF3b1 HEAT repeats. Moreover, these chimeric proteins confer a sensitivity to small molecule inhibition by pladienolide B to yeast splicing. Together, these data reveal the importance of individual contacts of Hsh155/SF3b1 to the U2/BS duplex and define their contribution to BS usage by the spliceosome.
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Affiliation(s)
- Tucker J Carrocci
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Joshua C Paulson
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Aaron A Hoskins
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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79
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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: 221] [Impact Index Per Article: 36.8] [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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80
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Finci LI, Zhang X, Huang X, Zhou Q, Tsai J, Teng T, Agrawal A, Chan B, Irwin S, Karr C, Cook A, Zhu P, Reynolds D, Smith PG, Fekkes P, Buonamici S, Larsen NA. The cryo-EM structure of the SF3b spliceosome complex bound to a splicing modulator reveals a pre-mRNA substrate competitive mechanism of action. Genes Dev 2018; 32:309-320. [PMID: 29491137 PMCID: PMC5859971 DOI: 10.1101/gad.311043.117] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/07/2018] [Indexed: 12/16/2022]
Abstract
In this study, Finci et. al. present the cryo-EM structure of the SF3b subcomplex (SF3B1, SF3B3, PHF5A, and SF3B5), part of the U2 snRNP, bound to E7107 at 3.95 A. The structure suggests a model in which splicing modulators interfere with branch point adenosine recognition and supports a substrate competitive mechanism of action. Somatic mutations in spliceosome proteins lead to dysregulated RNA splicing and are observed in a variety of cancers. These genetic aberrations may offer a potential intervention point for targeted therapeutics. SF3B1, part of the U2 small nuclear RNP (snRNP), is targeted by splicing modulators, including E7107, the first to enter clinical trials, and, more recently, H3B-8800. Modulating splicing represents a first-in-class opportunity in drug discovery, and elucidating the structural basis for the mode of action opens up new possibilities for structure-based drug design. Here, we present the cryogenic electron microscopy (cryo-EM) structure of the SF3b subcomplex (SF3B1, SF3B3, PHF5A, and SF3B5) bound to E7107 at 3.95 Å. This structure shows that E7107 binds in the branch point adenosine-binding pocket, forming close contacts with key residues that confer resistance upon mutation: SF3B1R1074H and PHF5AY36C. The structure suggests a model in which splicing modulators interfere with branch point adenosine recognition and supports a substrate competitive mechanism of action (MOA). Using several related chemical probes, we validate the pose of the compound and support their substrate competitive MOA by comparing their activity against both strong and weak pre-mRNA substrates. Finally, we present functional data and structure–activity relationship (SAR) on the PHF5AR38C mutation that sensitizes cells to some chemical probes but not others. Developing small molecule splicing modulators represents a promising therapeutic approach for a variety of diseases, and this work provides a significant step in enabling structure-based drug design for these elaborate natural products. Importantly, this work also demonstrates that the utilization of cryo-EM in drug discovery is coming of age.
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Affiliation(s)
- Lorenzo I Finci
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaofeng Zhang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xiuliang Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Qiang Zhou
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jennifer Tsai
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Teng Teng
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Anant Agrawal
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Betty Chan
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Sean Irwin
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Craig Karr
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Andrew Cook
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Ping Zhu
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | | | - Peter G Smith
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
| | - Peter Fekkes
- H3 Biomedicine, Inc., Cambridge, Massachusetts 02139, USA
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81
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Schneider-Poetsch T, Yoshida M. Along the Central Dogma-Controlling Gene Expression with Small Molecules. Annu Rev Biochem 2018; 87:391-420. [PMID: 29727582 DOI: 10.1146/annurev-biochem-060614-033923] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The central dogma of molecular biology, that DNA is transcribed into RNA and RNA translated into protein, was coined in the early days of modern biology. Back in the 1950s and 1960s, bacterial genetics first opened the way toward understanding life as the genetically encoded interaction of macromolecules. As molecular biology progressed and our knowledge of gene control deepened, it became increasingly clear that expression relied on many more levels of regulation. In the process of dissecting mechanisms of gene expression, specific small-molecule inhibitors played an important role and became valuable tools of investigation. Small molecules offer significant advantages over genetic tools, as they allow inhibiting a process at any desired time point, whereas mutating or altering the gene of an important regulator would likely result in a dead organism. With the advent of modern sequencing technology, it has become possible to monitor global cellular effects of small-molecule treatment and thereby overcome the limitations of classical biochemistry, which usually looks at a biological system in isolation. This review focuses on several molecules, especially natural products, that have played an important role in dissecting gene expression and have opened up new fields of investigation as well as clinical venues for disease treatment.
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Affiliation(s)
- Tilman Schneider-Poetsch
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan;
| | - Minoru Yoshida
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Saitama 351-0198, Japan; .,Department of Biotechnology, University of Tokyo, Tokyo 113-8657, Japan
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82
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Seiler M, Yoshimi A, Darman R, Chan B, Keaney G, Thomas M, Agrawal AA, Caleb B, Csibi A, Sean E, Fekkes P, Karr C, Klimek V, Lai G, Lee L, Kumar P, Lee SCW, Liu X, Mackenzie C, Meeske C, Mizui Y, Padron E, Park E, Pazolli E, Peng S, Prajapati S, Taylor J, Teng T, Wang J, Warmuth M, Yao H, Yu L, Zhu P, Abdel-Wahab O, Smith PG, Buonamici S. H3B-8800, an orally available small-molecule splicing modulator, induces lethality in spliceosome-mutant cancers. Nat Med 2018; 24:497-504. [PMID: 29457796 PMCID: PMC6730556 DOI: 10.1038/nm.4493] [Citation(s) in RCA: 345] [Impact Index Per Article: 57.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 01/10/2018] [Indexed: 12/19/2022]
Abstract
Genomic analyses of cancer have identified recurrent point mutations in the RNA splicing factor-encoding genes SF3B1, U2AF1, and SRSF2 that confer an alteration of function. Cancer cells bearing these mutations are preferentially dependent on wild-type (WT) spliceosome function, but clinically relevant means to therapeutically target the spliceosome do not currently exist. Here we describe an orally available modulator of the SF3b complex, H3B-8800, which potently and preferentially kills spliceosome-mutant epithelial and hematologic tumor cells. These killing effects of H3B-8800 are due to its direct interaction with the SF3b complex, as evidenced by loss of H3B-8800 activity in drug-resistant cells bearing mutations in genes encoding SF3b components. Although H3B-8800 modulates WT and mutant spliceosome activity, the preferential killing of spliceosome-mutant cells is due to retention of short, GC-rich introns, which are enriched for genes encoding spliceosome components. These data demonstrate the therapeutic potential of splicing modulation in spliceosome-mutant cancers.
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Affiliation(s)
| | - Akihide Yoshimi
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | | | - Betty Chan
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Gregg Keaney
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | | | | | | | | | | | - Peter Fekkes
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Craig Karr
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Virginia Klimek
- Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | | | - Linda Lee
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Pavan Kumar
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Stanley Chun-Wei Lee
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Xiang Liu
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | | | - Carol Meeske
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | | | - Eric Padron
- Department of Hematologic Malignancies and Immunology Program, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida, USA
| | - Eunice Park
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | | | | | | | - Justin Taylor
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teng Teng
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - John Wang
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | | | - Huilan Yao
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Lihua Yu
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Ping Zhu
- H3 Biomedicine Inc., Cambridge, Massachusetts, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
- Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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83
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Targeting the spliceosome for cutaneous squamous cell carcinoma therapy: a role for c-MYC and wild-type p53 in determining the degree of tumour selectivity. Oncotarget 2018; 9:23029-23046. [PMID: 29796170 PMCID: PMC5955416 DOI: 10.18632/oncotarget.25196] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/04/2018] [Indexed: 12/25/2022] Open
Abstract
We show that suppression of the spliceosome has potential for the treatment of cutaneous squamous cell carcinoma (cSCC). The small-molecule inhibitors of the spliceosome at the most advanced stage of development target the splicing factor SF3B1/SF3b155. The majority of cSCC cell lines are more sensitive than normal skin cells to death induced by the SF3B1 inhibitor pladienolide B. Knockdown of SF3B1 and a range of other splicing factors with diverse roles in the spliceosome can also selectively kill cSCC cells. We demonstrate that endogenous c-MYC participates in conferring sensitivity to spliceosome inhibition. c-MYC expression is elevated in cSCC lines and its knockdown reduces alterations in mRNA splicing and attenuates cell death caused by interference with the spliceosome. In addition, this study provides further support for a key role of the p53 pathway in the response to spliceosome disruption. SF3B1 inhibition causes wild-type p53 upregulation associated with altered mRNA splicing and reduced protein expression of both principal p53 negative regulators MDMX/MDM4 and MDM2. We observed that wild-type p53 can promote pladienolide B-induced death in tumour cells. However, p53 is commonly inactivated by mutation in cSCCs and p53 participates in killing normal skin cells at high concentrations of pladienolide B. This may limit the therapeutic window of SF3B1 inhibitors for cSCC. We provide evidence that, while suppression of SF3B1 has promise for treating cSCCs with mutant p53, inhibitors which target the spliceosome through SF3B1-independent mechanisms could have greater cSCC selectivity as a consequence of reduced p53 upregulation in normal cells.
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84
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Cretu C, Agrawal AA, Cook A, Will CL, Fekkes P, Smith PG, Lührmann R, Larsen N, Buonamici S, Pena V. Structural Basis of Splicing Modulation by Antitumor Macrolide Compounds. Mol Cell 2018; 70:265-273.e8. [DOI: 10.1016/j.molcel.2018.03.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 02/07/2018] [Accepted: 03/07/2018] [Indexed: 12/22/2022]
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85
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Alternative Splicing as a Target for Cancer Treatment. Int J Mol Sci 2018; 19:ijms19020545. [PMID: 29439487 PMCID: PMC5855767 DOI: 10.3390/ijms19020545] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 01/29/2018] [Accepted: 01/29/2018] [Indexed: 02/06/2023] Open
Abstract
Alternative splicing is a key mechanism determinant for gene expression in metazoan. During alternative splicing, non-coding sequences are removed to generate different mature messenger RNAs due to a combination of sequence elements and cellular factors that contribute to splicing regulation. A different combination of splicing sites, exonic or intronic sequences, mutually exclusive exons or retained introns could be selected during alternative splicing to generate different mature mRNAs that could in turn produce distinct protein products. Alternative splicing is the main source of protein diversity responsible for 90% of human gene expression, and it has recently become a hallmark for cancer with a full potential as a prognostic and therapeutic tool. Currently, more than 15,000 alternative splicing events have been associated to different aspects of cancer biology, including cell proliferation and invasion, apoptosis resistance and susceptibility to different chemotherapeutic drugs. Here, we present well established and newly discovered splicing events that occur in different cancer-related genes, their modification by several approaches and the current status of key tools developed to target alternative splicing with diagnostic and therapeutic purposes.
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86
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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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87
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Molecular basis of differential 3' splice site sensitivity to anti-tumor drugs targeting U2 snRNP. Nat Commun 2017; 8:2100. [PMID: 29235465 PMCID: PMC5727392 DOI: 10.1038/s41467-017-02007-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/30/2017] [Indexed: 01/21/2023] Open
Abstract
Several splicing-modulating compounds, including Sudemycins and Spliceostatin A, display anti-tumor properties. Combining transcriptome, bioinformatic and mutagenesis analyses, we delineate sequence determinants of the differential sensitivity of 3′ splice sites to these drugs. Sequences 5′ from the branch point (BP) region strongly influence drug sensitivity, with additional functional BPs reducing, and BP-like sequences allowing, drug responses. Drug-induced retained introns are typically shorter, displaying higher GC content and weaker polypyrimidine-tracts and BPs. Drug-induced exon skipping preferentially affects shorter alternatively spliced regions with weaker BPs. Remarkably, structurally similar drugs display both common and differential effects on splicing regulation, SSA generally displaying stronger effects on intron retention, and Sudemycins more acute effects on exon skipping. Collectively, our results illustrate how splicing modulation is exquisitely sensitive to the sequence context of 3′ splice sites and to small structural differences between drugs. Several families of natural compounds target core components of the pre-mRNA splicing machinery and display anti-tumor activity. Here the authors show that particular sequence features can be linked to drug response, and that drugs with very similar chemical structures display substantially different effects on splicing regulation.
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88
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Agrawal AA, Yu L, Smith PG, Buonamici S. Targeting splicing abnormalities in cancer. Curr Opin Genet Dev 2017; 48:67-74. [PMID: 29136527 DOI: 10.1016/j.gde.2017.10.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/19/2017] [Accepted: 10/13/2017] [Indexed: 01/11/2023]
Abstract
Recently splicing has been recognized as a key pathway in cancer. Although aberrant splicing has been shown to be a consequence of mutations or the abnormal expression of splicing factors (trans-effect changes) or mutations in the splicing sequences (cis-effect mutations), the connections between aberrant splicing and cancer initiation or progression are still not well understood. Here we review the mutational landscape of splicing factors in cancer and associated splicing consequences, along with the most important examples of the therapeutic approaches targeting the spliceosome currently being investigated in oncology.
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Affiliation(s)
| | - Lihua Yu
- H3 Biomedicine, Inc., Cambridge, MA, USA
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89
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Kielkopf CL. Insights from structures of cancer-relevant pre-mRNA splicing factors. Curr Opin Genet Dev 2017; 48:57-66. [PMID: 29128695 DOI: 10.1016/j.gde.2017.10.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 10/10/2017] [Accepted: 10/13/2017] [Indexed: 12/21/2022]
Abstract
Pre-mRNA splicing factors recognize consensus signals within preliminary transcripts, and as cogs of the spliceosome machine, orchestrate the excision and rejoining of pre-mRNA regions for gene expression. Large-scale sequencing has demonstrated that mutations in key genes encoding pre-mRNA splicing factors are common among myeloid neoplasms and also occur in a variety of other cancers. This revelation offers new therapeutic opportunities to target pre-mRNA splicing vulnerabilities in hematologic and other malignancies. The mutated residues typically alter 3' splice site choice for a subset of transcripts. In this review, we highlight mechanistic insights from recent 3D structures that reveal the affected residues poised for pre-mRNA recognition.
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Affiliation(s)
- Clara L Kielkopf
- Center for RNA Biology and Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
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90
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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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91
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Moriel-Carretero M, Ovejero S, Gérus-Durand M, Vryzas D, Constantinou A. Fanconi anemia FANCD2 and FANCI proteins regulate the nuclear dynamics of splicing factors. J Cell Biol 2017; 216:4007-4026. [PMID: 29030393 PMCID: PMC5716273 DOI: 10.1083/jcb.201702136] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 08/02/2017] [Accepted: 08/25/2017] [Indexed: 01/20/2023] Open
Abstract
Moriel-Carretero et al. show that the Fanconi anemia proteins FANCI and FANCD2 associate with the splicing factor SF3B1 and that DNA replication stress induces the FANCI-dependent release of SF3B1 from nuclear speckles. FANCI and FANCD2 prevent accumulation of postcatalytic intron lariats, suggesting that they help coordinate DNA replication and transcription. Proteins disabled in the cancer-prone disorder Fanconi anemia (FA) ensure the maintenance of chromosomal stability during DNA replication. FA proteins regulate replication dynamics, coordinate replication-coupled repair of interstrand DNA cross-links, and mitigate conflicts between replication and transcription. Here we show that FANCI and FANCD2 associate with splicing factor 3B1 (SF3B1), a key spliceosomal protein of the U2 small nuclear ribonucleoprotein (U2 snRNP). FANCI is in close proximity to SF3B1 in the nucleoplasm of interphase and mitotic cells. Furthermore, we find that DNA replication stress induces the release of SF3B1 from nuclear speckles in a manner that depends on FANCI and on the activity of the checkpoint kinase ATR. In chromatin, both FANCD2 and FANCI associate with SF3B1, prevent accumulation of postcatalytic intron lariats, and contribute to the timely eviction of splicing factors. We propose that FANCD2 and FANCI contribute to the organization of functional domains in chromatin, ensuring the coordination of DNA replication and cotranscriptional processes.
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Affiliation(s)
- María Moriel-Carretero
- Institute of Human Genetics, Centre National de la Recherche Scientifique UMR 9002, Université de Montpellier, Montpellier, France
| | - Sara Ovejero
- Institute of Human Genetics, Centre National de la Recherche Scientifique UMR 9002, Université de Montpellier, Montpellier, France
| | - Marie Gérus-Durand
- Institute of Human Genetics, Centre National de la Recherche Scientifique UMR 9002, Université de Montpellier, Montpellier, France
| | - Dimos Vryzas
- Institute of Human Genetics, Centre National de la Recherche Scientifique UMR 9002, Université de Montpellier, Montpellier, France
| | - Angelos Constantinou
- Institute of Human Genetics, Centre National de la Recherche Scientifique UMR 9002, Université de Montpellier, Montpellier, France
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92
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Lambert CA, Garbacki N, Colige AC. Chemotherapy induces alternative transcription and splicing: Facts and hopes for cancer treatment. Int J Biochem Cell Biol 2017; 91:84-97. [DOI: 10.1016/j.biocel.2017.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Revised: 04/04/2017] [Accepted: 04/15/2017] [Indexed: 01/14/2023]
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93
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León B, Kashyap MK, Chan WC, Krug KA, Castro JE, La Clair JJ, Burkart MD. A Challenging Pie to Splice: Drugging the Spliceosome. Angew Chem Int Ed Engl 2017; 56:12052-12063. [PMID: 28371109 PMCID: PMC6311392 DOI: 10.1002/anie.201701065] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Indexed: 02/05/2023]
Abstract
Since its discovery in 1977, the study of alternative RNA splicing has revealed a plethora of mechanisms that had never before been documented in nature. Understanding these transitions and their outcome at the level of the cell and organism has become one of the great frontiers of modern chemical biology. Until 2007, this field remained in the hands of RNA biologists. However, the recent identification of natural product and synthetic modulators of RNA splicing has opened new access to this field, allowing for the first time a chemical-based interrogation of RNA splicing processes. Simultaneously, we have begun to understand the vital importance of splicing in disease, which offers a new platform for molecular discovery and therapy. As with many natural systems, gaining clear mechanistic detail at the molecular level is key towards understanding the operation of any biological machine. This minireview presents recent lessons learned in this emerging field of RNA splicing chemistry and chemical biology.
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Affiliation(s)
- Brian León
- Department of Chemistry and Biochemistry, University of California, San Diego 9500, Gilman Drive, La Jolla CA, 92093-0358 (USA) ,
| | - Manoj K. Kashyap
- Moores Cancer Center and Department of Medicine, University of California, San Diego, La Jolla CA, 92093-0820 (USA)
| | - Warren C. Chan
- Department of Chemistry and Biochemistry, University of California, San Diego 9500, Gilman Drive, La Jolla CA, 92093-0358 (USA) ,
| | - Kelsey A. Krug
- Department of Chemistry and Biochemistry, University of California, San Diego 9500, Gilman Drive, La Jolla CA, 92093-0358 (USA) ,
| | - Januario E. Castro
- Moores Cancer Center and Department of Medicine, University of California, San Diego, La Jolla CA, 92093-0820 (USA)
| | - James J. La Clair
- Department of Chemistry and Biochemistry, University of California, San Diego 9500, Gilman Drive, La Jolla CA, 92093-0358 (USA) ,
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego 9500, Gilman Drive, La Jolla CA, 92093-0358 (USA) ,
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94
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León B, Kashyap MK, Chan WC, Krug KA, Castro JE, La Clair JJ, Burkart MD. Das Spliceosom als Angriffspunkt für Pharmaka. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201701065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Brian León
- Department of Chemistry and Biochemistry; University of California, San Diego; 9500 Gilman Drive La Jolla CA 92093-0358 USA
| | - Manoj K. Kashyap
- Moores Cancer Center and Department of Medicine; University of California, San Diego; La Jolla CA 92093-0820 USA
| | - Warren C. Chan
- Department of Chemistry and Biochemistry; University of California, San Diego; 9500 Gilman Drive La Jolla CA 92093-0358 USA
| | - Kelsey A. Krug
- Department of Chemistry and Biochemistry; University of California, San Diego; 9500 Gilman Drive La Jolla CA 92093-0358 USA
| | - Januario E. Castro
- Moores Cancer Center and Department of Medicine; University of California, San Diego; La Jolla CA 92093-0820 USA
| | - James J. La Clair
- Department of Chemistry and Biochemistry; University of California, San Diego; 9500 Gilman Drive La Jolla CA 92093-0358 USA
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry; University of California, San Diego; 9500 Gilman Drive La Jolla CA 92093-0358 USA
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95
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Targeting Splicing in the Treatment of Myelodysplastic Syndromes and Other Myeloid Neoplasms. Curr Hematol Malig Rep 2017; 11:408-415. [PMID: 27492253 DOI: 10.1007/s11899-016-0344-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Genome sequencing of primary cells from patients with myelodysplastic syndromes (MDS) led to the identification of recurrent heterozygous mutations in gene encoding components of the spliceosome, the cellular machinery which processes pre-messenger RNA (mRNA) to mature mRNA during gene transcription. Splicing mutations are mutually exclusive with one another and collectively represent the most common mutation class in MDS, occurring in approximately 60 % of patients overall and more than 80 % of those with ring sideroblasts. Evidence from animal models suggests that homozygous splicing mutations are lethal, and that in heterozygously mutated models, any further disruption of splicing triggers apoptosis and cell death. MDS cells with spliceosome mutations are thus uniquely vulnerable to therapies targeting splicing, which may be tolerated by healthy cells. The spliceosome is emerging as a novel therapeutic target in MDS and related myeloid neoplasms, with the first clinical trial of a splicing modulator opening in 2016.
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96
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Armstrong RN, Steeples V, Singh S, Sanchi A, Boultwood J, Pellagatti A. Splicing factor mutations in the myelodysplastic syndromes: target genes and therapeutic approaches. Adv Biol Regul 2017; 67:13-29. [PMID: 28986033 DOI: 10.1016/j.jbior.2017.09.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 09/19/2017] [Accepted: 09/21/2017] [Indexed: 10/25/2022]
Abstract
Mutations in splicing factor genes (SF3B1, SRSF2, U2AF1 and ZRSR2) are frequently found in patients with myelodysplastic syndromes (MDS), suggesting that aberrant spliceosome function plays a key role in the pathogenesis of MDS. Splicing factor mutations have been shown to result in aberrant splicing of many downstream target genes. Recent functional studies have begun to characterize the splicing dysfunction in MDS, identifying some key aberrantly spliced genes that are implicated in disease pathophysiology. These findings have led to the development of therapeutic strategies using splicing-modulating agents and rapid progress is being made in this field. Splicing inhibitors are promising agents that exploit the preferential sensitivity of splicing factor-mutant cells to these compounds. Here, we review the known target genes associated with splicing factor mutations in MDS, and discuss the potential of splicing-modulating therapies for these disorders.
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Affiliation(s)
- Richard N Armstrong
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK
| | - Violetta Steeples
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK
| | - Shalini Singh
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK
| | - Andrea Sanchi
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK
| | - Jacqueline Boultwood
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK.
| | - Andrea Pellagatti
- Bloodwise Molecular Haematology Unit, Nuffield Division of Clinical Laboratory Sciences, Radcliffe Department of Medicine, University of Oxford, and Oxford BRC Haematology Theme, Oxford, UK.
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97
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Lee SCW, Abdel-Wahab O. Therapeutic targeting of splicing in cancer. Nat Med 2017; 22:976-86. [PMID: 27603132 DOI: 10.1038/nm.4165] [Citation(s) in RCA: 385] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 07/13/2016] [Indexed: 02/07/2023]
Abstract
Recent studies have highlighted that splicing patterns are frequently altered in cancer and that mutations in genes encoding spliceosomal proteins, as well as mutations affecting the splicing of key cancer-associated genes, are enriched in cancer. In parallel, there is also accumulating evidence that several molecular subtypes of cancer are highly dependent on splicing function for cell survival. These findings have resulted in a growing interest in targeting splicing catalysis, splicing regulatory proteins, and/or specific key altered splicing events in the treatment of cancer. Here we present strategies that exist and that are in development to target altered dependency on the spliceosome, as well as aberrant splicing, in cancer. These include drugs to target global splicing in cancer subtypes that are preferentially dependent on wild-type splicing for survival, methods to alter post-translational modifications of splicing-regulating proteins, and strategies to modulate pathologic splicing events and protein-RNA interactions in cancer.
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Affiliation(s)
- Stanley Chun-Wei Lee
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center (MSKCC), New York, New York, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center (MSKCC), New York, New York, USA.,Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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98
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Pham D, Koide K. Discoveries, target identifications, and biological applications of natural products that inhibit splicing factor 3B subunit 1. Nat Prod Rep 2017; 33:637-47. [PMID: 26812544 DOI: 10.1039/c5np00110b] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Covering: 1992 to 2015The natural products FR901464, pladienolide, and herboxidiene were discovered as activators of reporter gene systems. Unexpectedly, these compounds target neither transcription nor translation; rather, they target splicing factor 3B subunit 1 of the spliceosome, causing changes in splicing patterns. All of them showed anticancer activity in a low nanomolar range. Since their discovery, these molecules have been used in a variety of biological applications.
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Affiliation(s)
- Dianne Pham
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, USA.
| | - Kazunori Koide
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260, USA.
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99
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Splicing modulators act at the branch point adenosine binding pocket defined by the PHF5A-SF3b complex. Nat Commun 2017; 8:15522. [PMID: 28541300 PMCID: PMC5458519 DOI: 10.1038/ncomms15522] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 04/05/2017] [Indexed: 01/28/2023] Open
Abstract
Pladienolide, herboxidiene and spliceostatin have been identified as splicing modulators that target SF3B1 in the SF3b subcomplex. Here we report that PHF5A, another component of this subcomplex, is also targeted by these compounds. Mutations in PHF5A-Y36, SF3B1-K1071, SF3B1-R1074 and SF3B1-V1078 confer resistance to these modulators, suggesting a common interaction site. RNA-seq analysis reveals that PHF5A-Y36C has minimal effect on basal splicing but inhibits the global action of splicing modulators. Moreover, PHF5A-Y36C alters splicing modulator-induced intron-retention/exon-skipping profile, which correlates with the differential GC content between adjacent introns and exons. We determine the crystal structure of human PHF5A demonstrating that Y36 is located on a highly conserved surface. Analysis of the cryo-EM spliceosome Bact complex shows that the resistance mutations cluster in a pocket surrounding the branch point adenosine, suggesting a competitive mode of action. Collectively, we propose that PHF5A–SF3B1 forms a central node for binding to these splicing modulators. A number of natural occurring small-molecule splicing modulators are known. Here, the authors combine chemogenomic, structural and biochemical methods and show that these compounds also target the spliceosome-associated protein PHF5A and propose a potential modulator binding site in the PHF5A–SF3B1 complex.
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100
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Kim Guisbert KS, Guisbert E. SF3B1 is a stress-sensitive splicing factor that regulates both HSF1 concentration and activity. PLoS One 2017; 12:e0176382. [PMID: 28445500 PMCID: PMC5406028 DOI: 10.1371/journal.pone.0176382] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 04/10/2017] [Indexed: 12/20/2022] Open
Abstract
The heat shock response (HSR) is a well-conserved, cytoprotective stress response that activates the HSF1 transcription factor. During severe stress, cells inhibit mRNA splicing which also serves a cytoprotective function via inhibition of gene expression. Despite their functional interconnectedness, there have not been any previous reports of crosstalk between these two pathways. In a genetic screen, we identified SF3B1, a core component of the U2 snRNP subunit of the spliceosome, as a regulator of the heat shock response in Caenorhabditis elegans. Here, we show that this regulatory connection is conserved in cultured human cells and that there are at least two distinct pathways by which SF3B1 can regulate the HSR. First, inhibition of SF3B1 with moderate levels of Pladienolide B, a previously established small molecule inhibitor of SF3B1, affects the transcriptional activation of HSF1, the transcription factor that mediates the HSR. However, both higher levels of Pladienolide B and SF3B1 siRNA knockdown also change the concentration of HSF1, a form of HSR regulation that has not been previously documented during normal physiology but is observed in some forms of cancer. Intriguingly, mutations in SF3B1 have also been associated with several distinct types of cancer. Finally, we show that regulation of alternative splicing by SF3B1 is sensitive to temperature, providing a new mechanism by which temperature stress can remodel the transcriptome.
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Affiliation(s)
- Karen S. Kim Guisbert
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States of America
| | - Eric Guisbert
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL, United States of America
- * E-mail:
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