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Mangalaparthi KK, Patel K, Khan AA, Nair B, Kumar RV, Prasad TSK, Sidransky D, Chatterjee A, Pandey A, Gowda H. Molecular Characterization of Esophageal Squamous Cell Carcinoma Using Quantitative Proteomics. Cancers (Basel) 2023; 15:3302. [PMID: 37444412 DOI: 10.3390/cancers15133302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 04/26/2023] [Accepted: 05/03/2023] [Indexed: 07/15/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is a heterogeneous cancer associated with a poor prognosis in advanced stages. In India, it is the sixth most common cause of cancer-related mortality. In this study, we employed high-resolution mass spectrometry-based quantitative proteomics to characterize the differential protein expression pattern associated with ESCC. We identified several differentially expressed proteins including PDPN, TOP2A, POSTN and MMP2 that were overexpressed in ESCC. In addition, we identified downregulation of esophagus tissue-enriched proteins such as SLURP1, PADI1, CSTA, small proline-rich proteins such as SPRR3, SPRR2A, SPRR1A, KRT4, and KRT13, involved in squamous cell differentiation. We identified several overexpressed proteins mapped to the 3q24-29 chromosomal region, aligning with CNV alterations in this region reported in several published studies. Among these, we identified overexpression of SOX2, TP63, IGF2BP2 and RNF13 that are encoded by genes in the 3q26 region. Functional enrichment analysis revealed proteins involved in cell cycle pathways, DNA replication, spliceosome, and DNA repair pathways. We identified the overexpression of multiple proteins that play a major role in alleviating ER stress, including SYVN1 and SEL1L. The SYVN1/SEL1L complex is an essential part of the ER quality control machinery clearing misfolded proteins from the ER. SYVN1 is an E3 ubiquitin ligase that ubiquitinates ER-resident proteins. Interestingly, there are also other non-canonical substrates of SYVN1 which are known to play a crucial role in tumor progression. Thus, SYVN1 could be a potential therapeutic target in ESCC.
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Affiliation(s)
- Kiran K Mangalaparthi
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Krishna Patel
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
| | - Aafaque Ahmad Khan
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
| | - Bipin Nair
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
| | - Rekha V Kumar
- Department of Pathology, Kidwai Memorial Institute of Oncology, Bangalore 560066, India
| | - Thottethodi Subrahmanya Keshav Prasad
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Mangalore 575018, India
| | - David Sidransky
- Department of Oncology, The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Department of Otolaryngology and Head & Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Aditi Chatterjee
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
- Manipal Academy of Higher Education, Manipal 576104, India
| | - Akhilesh Pandey
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
- Manipal Academy of Higher Education, Manipal 576104, India
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences, Hosur Road, Bangalore 560029, India
| | - Harsha Gowda
- Institute of Bioinformatics, International Technology Park, Bangalore 560066, India
- Amrita School of Biotechnology, Amrita Vishwa Vidyapeetham, Kollam 691001, India
- Manipal Academy of Higher Education, Manipal 576104, India
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2
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Liu Q, Fang L, Wu C. Alternative Splicing and Isoforms: From Mechanisms to Diseases. Genes (Basel) 2022; 13:genes13030401. [PMID: 35327956 PMCID: PMC8951537 DOI: 10.3390/genes13030401] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing of pre-mRNA is a key mechanism for increasing the complexity of proteins in humans, causing a diversity of expression of transcriptomes and proteomes in a tissue-specific manner. Alternative splicing is regulated by a variety of splicing factors. However, the changes and errors of splicing regulation caused by splicing factors are strongly related to many diseases, something which represents one of this study’s main interests. Further understanding of alternative splicing regulation mediated by cellular factors is also a prospective choice to develop specific drugs for targeting the dynamic RNA splicing process. In this review, we firstly concluded the basic principle of alternative splicing. Afterwards, we showed how splicing isoforms affect physiological activities through specific disease examples. Finally, the available treatment methods relative to adjusting splicing activities have been summarized.
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Wu J, Lu G, Wang X. MDM4 alternative splicing and implication in MDM4 targeted cancer therapies. Am J Cancer Res 2021; 11:5864-5880. [PMID: 35018230 PMCID: PMC8727814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 10/31/2021] [Indexed: 06/14/2023] Open
Abstract
The oncogenic MDM4, initially named MDMX, has been identified as a p53-interacting protein and a key upstream negative regulator of the tumor suppressor p53. Accumulating evidence indicates that MDM4 plays critical roles in the initiation and progression of multiple human cancers. MDM4 is frequently amplified and upregulated in human cancers, contributing to overgrowth and apoptosis inhibition by blocking the expression of downstream target genes of p53 pathway. Disruptors for MDM4-p53 interaction have been shown to restore the anti-tumor activity of p53 in cancer cells. MDM4 possesses multiple splicing isoforms whose expressions are driven by the presence of oncogenes in cancer cells. Some of the MDM4 splicing isoforms lack p53 binding domain and may exhibit p53-independent oncogenic functions. These features render MDM4 to be an attractive therapeutic target for cancer therapy. In the present review, we primarily focus on the detailed molecular structure of MDM4 splicing isoforms, candidate regulators for initiating MDM4 splicing, deregulation of MDM4 isoforms in cancer and potential therapy strategies by targeting splicing isoforms of MDM4.
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Affiliation(s)
- Jin Wu
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer CenterBuffalo, NY, USA
| | - Guanting Lu
- Department of Pathology, Key Laboratory of Tumor Molecular Research, People’s Hospital of Deyang City173 Tai Shan North Road, Deyang 618000, Sichuan, P. R. China
| | - Xinjiang Wang
- Department of Pharmacology and Therapeutics, Roswell Park Comprehensive Cancer CenterBuffalo, NY, USA
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4
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Xu X, Yin S, Ren Y, Hu C, Zhang A, Lin Y. Proteomics analysis reveals the correlation of programmed ROS-autophagy loop and dysregulated G1/S checkpoint with imatinib resistance in chronic myeloid leukemia cells. Proteomics 2021; 22:e2100094. [PMID: 34564948 DOI: 10.1002/pmic.202100094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/23/2021] [Accepted: 09/01/2021] [Indexed: 11/07/2022]
Abstract
Although tyrosine kinase inhibitors (TKIs), including imatinib, have greatly improved clinical treatment of patients with chronic myeloid leukemia (CML), drug resistance remains a major obstacle. Studies on the mechanisms underlying imatinib resistance and other alternative drugs are urgently needed. Liquid chromatography tandem mass spectrometry was applied to investigate the differences in proteomics and phosphoproteomics between K562 and K562/G (imatinib resistant K562). Multiple bioinformatics analyses were performed to unveil the differential signal pathways. CCK-8 was used to detect cell proliferation. Flow cytometry was performed to analyze reactive oxygen species (ROS), cell cycle, and cell apoptosis. Western blotting and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) were used to observe the changes of ROS and autophagy associated with imatinib resistance in CML. Our results indicated that ROS-autophagy formed one negative feedback loop and was associated with imatinib resistance. Additionally, the limited-rate enzymes of serine synthesis pathway were escalated in K562/G, which could contribute to the increased cyclin-dependent kinases and cell proliferation index. According to phosphoproteomics data, K562/G cells exhibited abnormal phosphorylation of splicing signals. These results revealed that it could be one useful strategy to correct metabolism shift and oxidative stress, or moderately regulate autophagy. Future research should focus on the discovery of potential targets in ROS-autophagy loop.
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Affiliation(s)
- Xiucai Xu
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Shihong Yin
- Department of Clinical Laboratory, The Fourth Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Yingli Ren
- Department of Clinical Laboratory, The Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China
| | - Chaojie Hu
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Aimei Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, People's Republic of China
| | - Ya Lin
- Wannan Medical College, Wuhu, Anhui, People's Republic of China
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5
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Supadmanaba IGP, Mantini G, Randazzo O, Capula M, Muller IB, Cascioferro S, Diana P, Peters GJ, Giovannetti E. Interrelationship between miRNA and splicing factors in pancreatic ductal adenocarcinoma. Epigenetics 2021; 17:381-404. [PMID: 34057028 PMCID: PMC8993068 DOI: 10.1080/15592294.2021.1916697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers because of diagnosis at late stage and inherent/acquired chemoresistance. Recent advances in genomic profiling and biology of this disease have not yet been translated to a relevant improvement in terms of disease management and patient’s survival. However, new possibilities for treatment may emerge from studies on key epigenetic factors. Deregulation of microRNA (miRNA) dependent gene expression and mRNA splicing are epigenetic processes that modulate the protein repertoire at the transcriptional level. These processes affect all aspects of PDAC pathogenesis and have great potential to unravel new therapeutic targets and/or biomarkers. Remarkably, several studies showed that they actually interact with each other in influencing PDAC progression. Some splicing factors directly interact with specific miRNAs and either facilitate or inhibit their expression, such as Rbfox2, which cleaves the well-known oncogenic miRNA miR-21. Conversely, miR-15a-5p and miR-25-3p significantly downregulate the splicing factor hnRNPA1 which acts also as a tumour suppressor gene and is involved in processing of miR-18a, which in turn, is a negative regulator of KRAS expression. Therefore, this review describes the interaction between splicing and miRNA, as well as bioinformatic tools to explore the effect of splicing modulation towards miRNA profiles, in order to exploit this interplay for the development of innovative treatments. Targeting aberrant splicing and deregulated miRNA, alone or in combination, may hopefully provide novel therapeutic approaches to fight the complex biology and the common treatment recalcitrance of PDAC.
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Affiliation(s)
- I Gede Putu Supadmanaba
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands.,Biochemistry Department, Faculty of Medicine, Universitas Udayana, Denpasar, Bali, Indonesia
| | - Giulia Mantini
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands.,Cancer Pharmacology Lab, AIRC Start up Unit, Fondazione Pisana per La Scienza, Pisa, Italy
| | - Ornella Randazzo
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands.,Dipartimento Di Scienze E Tecnologie Biologiche Chimiche E Farmaceutiche (STEBICEF), Università Degli Studi Di Palermo, Palermo, Italy
| | - Mjriam Capula
- Cancer Pharmacology Lab, AIRC Start up Unit, Fondazione Pisana per La Scienza, Pisa, Italy.,Institute of Life Sciences, Sant'Anna School of Advanced Studies, Pisa, Italy
| | - Ittai B Muller
- Department of Clinical Chemistry, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands
| | - Stella Cascioferro
- Dipartimento Di Scienze E Tecnologie Biologiche Chimiche E Farmaceutiche (STEBICEF), Università Degli Studi Di Palermo, Palermo, Italy
| | - Patrizia Diana
- Dipartimento Di Scienze E Tecnologie Biologiche Chimiche E Farmaceutiche (STEBICEF), Università Degli Studi Di Palermo, Palermo, Italy
| | - Godefridus J Peters
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands.,Department of Biochemistry, Medical University of Gdansk, Poland
| | - Elisa Giovannetti
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUMC), Amsterdam, The Netherlands.,Cancer Pharmacology Lab, AIRC Start up Unit, Fondazione Pisana per La Scienza, Pisa, Italy
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6
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Schneider-Poetsch T, Chhipi-Shrestha JK, Yoshida M. Splicing modulators: on the way from nature to clinic. J Antibiot (Tokyo) 2021; 74:603-616. [PMID: 34345042 PMCID: PMC8472923 DOI: 10.1038/s41429-021-00450-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 02/06/2023]
Abstract
Over the course of more than two decades, natural products isolated from various microorganisms and plants have built the foundation for chemical biology research into the mechanism of pre-mRNA splicing. Hand in hand with advances in scientific methodology small molecule splicing modulators have become powerful tools for investigating, not just the splicing mechanism, but also the cellular effect of altered mRNA processing. Based on thorough structure-activity studies, synthetic analogues have moved on from scientific tool compounds to experimental drugs. With current advances in drug discovery methodology and new means of attacking targets previously thought undruggable, we can expect further advances in both research and therapeutics based on small molecule splicing modulators.
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Affiliation(s)
- Tilman Schneider-Poetsch
- grid.509461.fChemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama Japan
| | | | - Minoru Yoshida
- grid.509461.fChemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, Wako, Saitama Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Biotechnology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo Japan ,grid.26999.3d0000 0001 2151 536XCollaborative Research Institute for Innovative Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo Japan
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7
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López-Cánovas JL, Del Rio-Moreno M, García-Fernandez H, Jiménez-Vacas JM, Moreno-Montilla MT, Sánchez-Frias ME, Amado V, L-López F, Fondevila MF, Ciria R, Gómez-Luque I, Briceño J, Nogueiras R, de la Mata M, Castaño JP, Rodriguez-Perálvarez M, Luque RM, Gahete MD. Splicing factor SF3B1 is overexpressed and implicated in the aggressiveness and survival of hepatocellular carcinoma. Cancer Lett 2021; 496:72-83. [PMID: 33038489 DOI: 10.1016/j.canlet.2020.10.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 12/19/2022]
Abstract
Splicing alterations represent an actionable cancer hallmark. Splicing factor 3B subunit 1 (SF3B1) is a crucial splicing factor that can be targeted pharmacologically (e.g. pladienolide-B). Here, we show that SF3B1 is overexpressed (RNA/protein) in hepatocellular carcinoma (HCC) in two retrospective (n = 154 and n = 172 samples) and in five in silico cohorts (n > 900 samples, including TCGA) and that its expression is associated with tumor aggressiveness, oncogenic splicing variants expression (KLF6-SV1, BCL-XL) and decreased overall survival. In vitro, SF3B1 silencing reduced cell viability, proliferation and migration and its pharmacological blockade with pladienolide-B inhibited proliferation, migration, and formation of tumorspheres and colonies in liver cancer cell lines (HepG2, Hep3B, SNU-387), whereas its effects on normal-like hepatocyte-derived THLE-2 proliferation were negligible. Pladienolide-B also reduced the in vivo growth and the expression of tumor-markers in Hep3B-induced xenograft tumors. Moreover, SF3B1 silencing and/or blockade markedly modulated the activation of key signaling pathways (PDK1, GSK3b, ERK, JNK, AMPK) and the expression of cancer-associated genes (CDK4, CD24) and oncogenic SVs (KLF6-SV1). Therefore, the genetic and/or pharmacological inhibition of SF3B1 may represent a promising novel therapeutic strategy worth to be explored through randomized controlled trials.
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Affiliation(s)
- Juan L López-Cánovas
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Mercedes Del Rio-Moreno
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Helena García-Fernandez
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Juan M Jiménez-Vacas
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - M Trinidad Moreno-Montilla
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Marina E Sánchez-Frias
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain
| | - Víctor Amado
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Hepatology and Liver Transplantation, Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Hepatic and Digestive Diseases (CIBERehd), Córdoba, 14004, Spain
| | - Fernando L-López
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Marcos F Fondevila
- CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain; Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain
| | - Rubén Ciria
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Unit of Hepatobiliary Surgery and Liver Transplantation, Reina Sofía University Hospital, Cordoba, 14004, Spain
| | - Irene Gómez-Luque
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Unit of Hepatobiliary Surgery and Liver Transplantation, Reina Sofía University Hospital, Cordoba, 14004, Spain
| | - Javier Briceño
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Unit of Hepatobiliary Surgery and Liver Transplantation, Reina Sofía University Hospital, Cordoba, 14004, Spain
| | - Rubén Nogueiras
- CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain; Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain
| | - Manuel de la Mata
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Hepatology and Liver Transplantation, Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Hepatic and Digestive Diseases (CIBERehd), Córdoba, 14004, Spain
| | - Justo P Castaño
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Manuel Rodriguez-Perálvarez
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Hepatology and Liver Transplantation, Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Hepatic and Digestive Diseases (CIBERehd), Córdoba, 14004, Spain
| | - Raúl M Luque
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain
| | - Manuel D Gahete
- Maimónides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, 14004, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, 14004, Spain; Reina Sofía University Hospital, Córdoba, 14004, Spain; CIBER Pathophysiology of Obesity and Nutrition (CIBERobn), Córdoba, 14004, Spain.
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8
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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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9
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McHugh A, Fernandes K, Chinner N, Ibrahim AFM, Garg AK, Boag G, Hepburn LA, Proby CM, Leigh IM, Saville MK. The Identification of Potential Therapeutic Targets for Cutaneous Squamous Cell Carcinoma. J Invest Dermatol 2019; 140:1154-1165.e5. [PMID: 31705877 PMCID: PMC7254059 DOI: 10.1016/j.jid.2019.09.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 08/27/2019] [Accepted: 09/23/2019] [Indexed: 02/06/2023]
Abstract
We performed a small interfering RNA screen to identify targets for cutaneous squamous cell carcinoma (cSCC) therapy in the ubiquitin/ubiquitin-like system. We provide evidence for selective anti-cSCC activity of knockdown of the E3 ubiquitin ligase MARCH4, the ATPase p97/VCP, the deubiquitinating enzyme USP8, the cullin-RING ligase (CRL) 4 substrate receptor CDT2/DTL, and components of the anaphase-promoting complex/cyclosome (APC/C). Specifically attenuating CRL4CDT2 by CDT2 knockdown can be more potent in killing cSCC cells than targeting CRLs or CRL4s in general by RBX1 or DDB1 depletion. Suppression of the APC/C or forced APC/C activation by targeting its repressor EMI1 are both potential therapeutic approaches. We observed that cSCC cells can be selectively killed by small-molecule inhibitors of USP8 (DUBs-IN-3/compound 22c) and the NEDD8 E1 activating enzyme/CRLs (MLN4924/pevonedistat). A substantial proportion of cSCC cell lines are very highly MLN4924-sensitive. Pathways that respond to defects in proteostasis are involved in the anti-cSCC activity of p97 suppression. Targeting USP8 can reduce the expression of growth factor receptors that participate in cSCC development. EMI1 and CDT2 depletion can selectively cause DNA re-replication and DNA damage in cSCC cells.
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Affiliation(s)
- Angela McHugh
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Kenneth Fernandes
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Nerime Chinner
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Adel F M Ibrahim
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Amit K Garg
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Garry Boag
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Lydia A Hepburn
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Charlotte M Proby
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom; Division of Molecular and Clinical Medicine, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Irene M Leigh
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom; Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Mark K Saville
- Division of Cancer Research, School of Medicine, University of Dundee, Dundee, United Kingdom.
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10
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Jiménez-Vacas JM, Herrero-Aguayo V, Gómez-Gómez E, León-González AJ, Sáez-Martínez P, Alors-Pérez E, Fuentes-Fayos AC, Martínez-López A, Sánchez-Sánchez R, González-Serrano T, López-Ruiz DJ, Requena-Tapia MJ, Castaño JP, Gahete MD, Luque RM. Spliceosome component SF3B1 as novel prognostic biomarker and therapeutic target for prostate cancer. Transl Res 2019; 212:89-103. [PMID: 31344348 DOI: 10.1016/j.trsl.2019.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 06/19/2019] [Accepted: 07/05/2019] [Indexed: 12/27/2022]
Abstract
Prostate cancer (PCa) is one of the most common cancers types among men. Development and progression of PCa is associated with aberrant expression of oncogenic splicing-variants (eg, AR-v7), suggesting that dysregulation of the splicing process might represent a potential actionable target for PCa. Expression levels (mRNA and protein) of SF3B1, one of the main components of the splicing machinery, were analyzed in different cohorts of PCa patients (clinically localized [n = 84], highly aggressive PCa [n = 42], and TCGA dataset [n = 497]). Functional and mechanistic assays were performed in response to pladienolide-B in nontumor and tumor-derived prostate cells. Our results revealed that SF3B1 was overexpressed in PCa tissues and its levels were associated with clinically relevant PCa-aggressive features (eg, metastasis/AR-v7 expression). Moreover, inhibition of SF3B1 activity by pladienolide-B reduced functional parameters of aggressiveness (proliferation/migration/tumorspheres-formation/apoptosis) in PCa cell lines, irrespective of AR-v7 expression, and reduced viability of primary PCa cells. Antitumor actions of pladienolide-B involved: (1) inhibition of PI3K/AKT and JNK signaling pathways, (2) modulation of tumor markers and splicing variants (AR-v7/In1-ghrelin), and (3) regulation of key components of mRNA homeostasis-associated machineries (spliceosome/SURF/EJC). Altogether, our results demonstrated that SF3B1 is overexpressed and associated with malignant features in PCa, and its inhibition reduces PCa aggressiveness, suggesting that SF3B1 could represent a novel prognostic biomarker and a therapeutic target in PCa.
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Affiliation(s)
- Juan M Jiménez-Vacas
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Vicente Herrero-Aguayo
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Enrique Gómez-Gómez
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS/IMIBIC, Córdoba, Spain
| | - Antonio J León-González
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Prudencio Sáez-Martínez
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Emilia Alors-Pérez
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Antonio C Fuentes-Fayos
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Ana Martínez-López
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - Rafael Sánchez-Sánchez
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - Teresa González-Serrano
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - Daniel J López-Ruiz
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Radiology Service, HURS/IMIBIC
| | - María J Requena-Tapia
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS/IMIBIC, Córdoba, Spain
| | - Justo P Castaño
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Manuel D Gahete
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain
| | - Raúl M Luque
- Maimonides Institute for Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology, and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición, (CIBERobn), Córdoba, Spain.
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11
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Hassan S, Purdie KJ, Wang J, Harwood CA, Proby CM, Pourreyron C, Mladkova N, Nagano A, Dhayade S, Athineos D, Caley M, Mannella V, Blyth K, Inman GJ, Leigh IM. A Unique Panel of Patient-Derived Cutaneous Squamous Cell Carcinoma Cell Lines Provides a Preclinical Pathway for Therapeutic Testing. Int J Mol Sci 2019; 20:E3428. [PMID: 31336867 PMCID: PMC6678499 DOI: 10.3390/ijms20143428] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 06/28/2019] [Accepted: 07/04/2019] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Cutaneous squamous cell carcinoma (cSCC) incidence continues to rise with increasing morbidity and mortality, with limited treatment options for advanced disease. Future improvements in targeted therapy will rely on advances in genomic/transcriptomic understanding and the use of model systems for basic research. We describe here the panel of 16 primary and metastatic cSCC cell lines developed and characterised over the past three decades in our laboratory in order to provide such a resource for future preclinical research and drug screening. METHODS Primary keratinocytes were isolated from cSCC tumours and metastases, and cell lines were established. These were characterised using short tandem repeat (STR) profiling and genotyped by whole exome sequencing. Multiple in vitro assays were performed to document their morphology, growth characteristics, migration and invasion characteristics, and in vivo xenograft growth. RESULTS STR profiles of the cSCC lines allow the confirmation of their unique identity. Phylogenetic trees derived from exome sequence analysis of the matched primary and metastatic lines provide insight into the genetic basis of disease progression. The results of in vivo and in vitro analyses allow researchers to select suitable cell lines for specific experimentation. CONCLUSIONS There are few well-characterised cSCC lines available for widespread preclinical experimentation and drug screening. The described cSCC cell line panel provides a critical tool for in vitro and in vivo experimentation.
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Affiliation(s)
- Sakinah Hassan
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Karin J Purdie
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Jun Wang
- Barts Cancer Institute, QMUL, London EC1M 6BQ, UK
| | - Catherine A Harwood
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Charlotte M Proby
- Division of Cancer, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK
| | - Celine Pourreyron
- Division of Cancer, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK
| | - Nikol Mladkova
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Ai Nagano
- Barts Cancer Institute, QMUL, London EC1M 6BQ, UK
| | - Sandeep Dhayade
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - Dimitris Athineos
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - Matthew Caley
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Viviana Mannella
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK
| | - Karen Blyth
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
| | - Gareth J Inman
- Cancer Research UK Beatson Institute, Garscube Estate, Switchback Rd, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1GH, UK
| | - Irene M Leigh
- Blizard Institute, Barts and the London School of Medicine and Dentistry, QMUL, London E1 2AT, UK.
- Division of Cancer, Ninewells Hospital and Medical School, University of Dundee, Dundee DD1 9SY, UK.
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12
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Apoptosis induction and cell cycle arrest of pladienolide B in erythroleukemia cell lines. Invest New Drugs 2019; 38:369-377. [DOI: 10.1007/s10637-019-00796-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 05/22/2019] [Indexed: 12/21/2022]
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13
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de Fraipont F, Gazzeri S, Cho WC, Eymin B. Circular RNAs and RNA Splice Variants as Biomarkers for Prognosis and Therapeutic Response in the Liquid Biopsies of Lung Cancer Patients. Front Genet 2019; 10:390. [PMID: 31134126 PMCID: PMC6514155 DOI: 10.3389/fgene.2019.00390] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/10/2019] [Indexed: 01/08/2023] Open
Abstract
Lung cancer, including non-small cell lung carcinoma (NSCLC), is the most frequently diagnosed cancer. It is also the leading cause of cancer-related mortality worldwide because of its late diagnosis and its resistance to therapies. Therefore, the identification of biomarkers for early diagnosis, prognosis, and monitoring of therapeutic response is urgently needed. Liquid biopsies, especially blood, are considered as promising tools to detect and quantify circulating cancer biomarkers. Cell-free circulating tumor DNA has been extensively studied. Recently, the possibility to detect and quantify RNAs in tumor biopsies, notably circulating cell-free RNAs, has gained great attention. RNA alternative splicing contributes to the proteome diversity through the biogenesis of several mRNA splice variants from the same pre-mRNA. Circular RNA (circRNA) is a new class of RNAs resulting from pre-mRNA back splicing. Owing to the development of high-throughput transcriptomic analyses, numerous RNA splice variants and, more recently, circRNAs have been identified and found to be differentially expressed in tumor patients compared to healthy controls. The contribution of some of these RNA splice variants and circRNAs to tumor progression, dissemination, or drug response has been clearly demonstrated in preclinical models. In this review, we discuss the potential of circRNAs and mRNA splice variants as candidate biomarkers for the prognosis and the therapeutic response of NSCLC in liquid biopsies.
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Affiliation(s)
- Florence de Fraipont
- INSERM U1209, CNRS UMR5309, Institute for Advanced Biosciences, University Grenoble Alpes, Grenoble, France.,Grenoble Hospital, La Tronche, France
| | - Sylvie Gazzeri
- INSERM U1209, CNRS UMR5309, Institute for Advanced Biosciences, University Grenoble Alpes, Grenoble, France
| | - William C Cho
- Department of Clinical Oncology, Queen Elizabeth Hospital, Kowloon, Hong Kong
| | - Beatrice Eymin
- INSERM U1209, CNRS UMR5309, Institute for Advanced Biosciences, University Grenoble Alpes, Grenoble, France
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14
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DeNicola AB, Tang Y. Therapeutic approaches to treat human spliceosomal diseases. Curr Opin Biotechnol 2019; 60:72-81. [PMID: 30772756 DOI: 10.1016/j.copbio.2019.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/02/2019] [Indexed: 02/06/2023]
Abstract
Mutated RNA splicing machinery drives many human diseases and is a promising therapeutic target for engineering and small molecule therapy. In the case of mutations in individual genes that cause them to be incorrectly spliced, engineered splicing factors can be introduced to correct splicing of these aberrant transcripts and reduce the effects of the disease phenotype. Mutations that occur in certain splicing factor genes themselves have been implicated in many cancers, particularly myelodysplastic syndromes. Small molecules that target splicing factors have been developed as therapies to preferentially induce apoptosis in these cancer cells. Specifically, drugs targeting the splicing factor SF3B1 have led to recent clinical trials. Here, we review the role of alternative splicing in disease, approaches to rescue incorrect splicing using engineered splicing factors, and small molecule splicing inhibitors developed to treat hematological cancers.
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Affiliation(s)
- Anthony B DeNicola
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, United States.
| | - Yi Tang
- Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095, United States
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15
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Annalora AJ, Jozic M, Marcus CB, Iversen PL. Alternative splicing of the vitamin D receptor modulates target gene expression and promotes ligand-independent functions. Toxicol Appl Pharmacol 2018; 364:55-67. [PMID: 30552932 DOI: 10.1016/j.taap.2018.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/04/2018] [Accepted: 12/10/2018] [Indexed: 02/07/2023]
Abstract
Alternative splicing modulates gene function by creating splice variants with alternate functions or non-coding RNA activity. Naturally occurring variants of nuclear receptor (NR) genes with dominant negative or gain-of-function phenotypes have been documented, but their cellular roles, regulation, and responsiveness to environmental stress or disease remain unevaluated. Informed by observations that class I androgen and estrogen receptor variants display ligand-independent signaling in human cancer tissues, we questioned whether the function of class II NRs, like the vitamin D receptor (VDR), would also respond to alternative splicing regulation. Artificial VDR constructs lacking exon 3 (Dex3-VDR), encoding part of the DNA binding domain (DBD), and exon 8 (Dex8-VDR), encoding part of the ligand binding domain (LBD), were transiently transfected into DU-145 cells and stably-integrated into Caco-2 cells to study their effect on gene expression and cell viability. Changes in VDR promoter signaling were monitored by the expression of target genes (e.g. CYP24A1, CYP3A4 and CYP3A5). Ligand-independent VDR signaling was observed in variants lacking exon 8, and a significant loss of gene suppressor function was documented for variants lacking exon 3. The gain-of-function behavior of the Dex8-VDR variant was recapitulated in vitro using antisense oligonucleotides (ASO) that induce the skipping of exon 8 in wild-type VDR. ASO targeting the splice acceptor site of exon 8 significantly stimulated ligand-independent VDR reporter activity and the induction of CYP24A1 above controls. These results demonstrate how alternative splicing can re-program NR gene function, highlighting novel mechanisms of toxicity and new opportunities for the use of splice-switching oligonucleotides (SSO) in precision medicine.
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Affiliation(s)
- Andrew J Annalora
- Department of Environmental and Molecular Toxicology, Oregon State University, 1007 Agriculture & Life Sciences Building, Corvallis, OR 97331; USA.
| | - Marija Jozic
- Department of Environmental and Molecular Toxicology, Oregon State University, 1007 Agriculture & Life Sciences Building, Corvallis, OR 97331; USA
| | - Craig B Marcus
- Department of Environmental and Molecular Toxicology, Oregon State University, 1007 Agriculture & Life Sciences Building, Corvallis, OR 97331; USA
| | - Patrick L Iversen
- Department of Environmental and Molecular Toxicology, Oregon State University, 1007 Agriculture & Life Sciences Building, Corvallis, OR 97331; USA; LS Pharma, 884 Park St., Lebanon, OR 97355; USA
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