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Wang CX, Liu F, Wang Y. RBM5 suppresses proliferation, metastasis and glycolysis of colorectal cancer cells via stabilizing phosphatase and tensin homolog mRNA. World J Gastrointest Oncol 2024; 16:3241-3255. [PMID: 39072172 PMCID: PMC11271791 DOI: 10.4251/wjgo.v16.i7.3241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 05/07/2024] [Accepted: 05/24/2024] [Indexed: 07/12/2024] Open
Abstract
BACKGROUND RNA binding motif 5 (RBM5) has emerged as crucial regulators in many cancers. AIM To explore more functional and mechanistic exploration of RBM5 since the lack of research on RBM5 in colorectal cancer (CRC) dictates that is essential. METHODS Through Gene Expression Profiling Interactive Analysis, we analyzed RBM5 expression in colon adenocarcinoma and rectum adenocarcinoma tissues. For detecting the mRNA expression of RBM5, quantitative real time-polymerase chain reaction was performed. Protein expression levels of RBM5, hexokinase 2, lactate dehydrogenase A, phosphatase and tensin homolog (PTEN), phosphoinositide 3-kinase (PI3K), phosphorylated-protein kinase B (p-AKT), and AKT were determined via Western blot. Functionally, cell counting kit-8 and 5-ethynyl-2'-deoxyuridine (EDU) assay were performed to evaluate proliferation of CRC cells. Invasiveness and migration of CRC cells were evaluated through conducting transwell assays. Glucose consumption, lactate production and adenosine-triphosphate (ATP) production were measured through a glucose assay kit, a lactate assay kit and an ATP production assay kit, respectively. Besides, RNA immunoprecipitation assay, half-life RT-PCR and dual-luciferase reporter assay were applied to detect interaction between RBM5 and PTEN. To establish a xenotypic tumor mice, CRC cells were subcutaneously injected into the right flank of each mouse. Protein expression of RBM5, Ki67, and PTEN in tumor tissues was examined using immunohistochemistry staining. Haematoxylin and eosin staining was used to evaluate tumor liver metastasis in mice. RESULTS We discovered down-regulation of RBM5 expression in CRC tissues and cells. RBM5 overexpression repressed proliferation, migration and invasion of CRC cells. Meantime, RBM5 impaired glycolysis in CRC cells, presenting as decreased glucose consumption, decreased lactate production and decreased ATP production. Besides, RBM5 bound to PTEN mRNA to stabilize its expression. PTEN expression was positively regulated by RBM5 in CRC cells. The protein levels of PI3K and p-AKT were significantly decreased after RBM5 overexpression. The suppressive influences of RBM5 on glycolysis, proliferation and metastasis of CRC cells were partially counteracted by PTEN knockdown. RBM5 suppressed tumor growth and liver metastasis in vivo. CONCLUSION This investigation provided new evidence that RBM5 was involved in CRC by binding to PTEN, expanding the importance of RBM5 in the treatment of CRC.
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Affiliation(s)
- Chu-Xiang Wang
- Department of Anorectal Surgery, The Affiliated Hospital of Dalian Medical University, Dalian 116000, Liaoning Province, China
| | - Feng Liu
- Department of Scientific Research, Beijing Fresta Technologies Co, Ltd., Beijing 100176, China
| | - Yi Wang
- Department of VIP Medical Services, National Cancer Center, National Clinical Research Center for Cancer, Cancer Hospital Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China
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2
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Zhou X, Cao Y, Li R, Di X, Wang Y, Wang K. PEI, a new transfection method, augments the inhibitory effect of RBM5 on prostate cancer. Biochem Biophys Res Commun 2024; 704:149703. [PMID: 38402723 DOI: 10.1016/j.bbrc.2024.149703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Accepted: 02/20/2024] [Indexed: 02/27/2024]
Abstract
PEI is a cationic polymer, serving as a non-viral transfection carrier grounded in nanotechnology that enhances transfection efficiency via the proton sponge effect. RBM5 is an RNA-binding protein that can inhibit tumor development. This study involved the transfection of RBM5 in prostate cancer cells with PEI, Lipo2000, and their combination. Transwell and wound healing assays were used to observe invasion and migration of prostate cancer cells and flow cytometry was used to observe the apoptosis. Detect the expression of invasion and migration-related protein MMP9 through western blotting experiment. An activity detection kit was used to detect the activity of apoptotic protein caspase-3. We found that there was no significant difference in transfection efficiency when PEI and Lipo2000 were used alone but it significantly improved when they are combined. RBM5 reduced invasion, migration, and proliferation of prostate cancer and enhanced apoptosis. MMP9 expression was reduced, and the activity of caspase-3 was increased. PEI transfection could improve the inhibition of RBM5 on tumors more than Lipo2000. The inhibitory effect is more obvious when the two are used together. RBM5 transfected with PEI can amplify its inhibitory effect on prostate cancer, and this effect is more evident when combined with Lipo2000.
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Affiliation(s)
- Xijia Zhou
- Department of Respiratory and Critical Care Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Yingshu Cao
- Department of Respiratory and Critical Care Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Ranwei Li
- Department of Urinary Surgery, The Second Hospital of Jilin University, Changchun, China
| | - Xin Di
- Department of Respiratory and Critical Care Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Yanqiao Wang
- Department of Respiratory and Critical Care Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Ke Wang
- Department of Respiratory and Critical Care Medicine, The Second Hospital of Jilin University, Changchun, China.
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3
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Soni K, Jagtap PKA, Martínez-Lumbreras S, Bonnal S, Geerlof A, Stehle R, Simon B, Valcárcel J, Sattler M. Structural basis for specific RNA recognition by the alternative splicing factor RBM5. Nat Commun 2023; 14:4233. [PMID: 37454201 PMCID: PMC10349855 DOI: 10.1038/s41467-023-39961-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 07/05/2023] [Indexed: 07/18/2023] Open
Abstract
The RNA-binding motif protein RBM5 belongs to a family of multi-domain RNA binding proteins that regulate alternative splicing of genes important for apoptosis and cell proliferation and have been implicated in cancer. RBM5 harbors structural modules for RNA recognition, such as RRM domains and a Zn finger, and protein-protein interactions such as an OCRE domain. Here, we characterize binding of the RBM5 RRM1-ZnF1-RRM2 domains to cis-regulatory RNA elements. A structure of the RRM1-ZnF1 region in complex with RNA shows how the tandem domains cooperate to sandwich target RNA and specifically recognize a GG dinucleotide in a non-canonical fashion. While the RRM1-ZnF1 domains act as a single structural module, RRM2 is connected by a flexible linker and tumbles independently. However, all three domains participate in RNA binding and adopt a closed architecture upon RNA binding. Our data highlight how cooperativity and conformational modularity of multiple RNA binding domains enable the recognition of distinct RNA motifs, thereby contributing to the regulation of alternative splicing. Remarkably, we observe surprising differences in coupling of the RNA binding domains between the closely related homologs RBM5 and RBM10.
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Affiliation(s)
- Komal Soni
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Pravin Kumar Ankush Jagtap
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Santiago Martínez-Lumbreras
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Sophie Bonnal
- Centre de Regulació Genòmica, Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Barcelona, Spain
| | - Arie Geerlof
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Ralf Stehle
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Lichtenbergstrasse 4, 85748, Garching, Germany
| | - Bernd Simon
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117, Heidelberg, Germany
| | - Juan Valcárcel
- Centre de Regulació Genòmica, Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Michael Sattler
- Helmholtz Munich, Molecular Targets and Therapeutics Center, Institute of Structural Biology, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
- Technical University of Munich, TUM School of Natural Sciences, Department of Bioscience, Bavarian NMR Center, Lichtenbergstrasse 4, 85748, Garching, Germany.
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4
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Montero-Hidalgo AJ, Pérez-Gómez JM, Martínez-Fuentes AJ, Gómez-Gómez E, Gahete MD, Jiménez-Vacas JM, Luque RM. Alternative splicing in bladder cancer: potential strategies for cancer diagnosis, prognosis, and treatment. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1760. [PMID: 36063028 DOI: 10.1002/wrna.1760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 07/25/2022] [Accepted: 08/05/2022] [Indexed: 05/13/2023]
Abstract
Bladder cancer is the most common malignancy of the urinary tract worldwide. The therapeutic options to tackle this disease comprise surgery, intravesical or systemic chemotherapy, and immunotherapy. Unfortunately, a wide number of patients ultimately become resistant to these treatments and develop aggressive metastatic disease, presenting a poor prognosis. Therefore, the identification of novel therapeutic approaches to tackle this devastating pathology is urgently needed. However, a significant limitation is that the progression and drug response of bladder cancer is strongly associated with its intrinsic molecular heterogeneity. In this sense, RNA splicing is recently gaining importance as a critical hallmark of cancer since can have a significant clinical value. In fact, a profound dysregulation of the splicing process has been reported in bladder cancer, especially in the expression of certain key splicing variants and circular RNAs with a potential clinical value as diagnostic/prognostic biomarkers or therapeutic targets in this pathology. Indeed, some authors have already evidenced a profound antitumor effect by targeting some splicing factors (e.g., PTBP1), mRNA splicing variants (e.g., PKM2, HYAL4-v1), and circular RNAs (e.g., circITCH, circMYLK), which illustrates new possibilities to significantly improve the management of this pathology. This review represents the first detailed overview of the splicing process and its alterations in bladder cancer, and highlights opportunities for the development of novel diagnostic/prognostic biomarkers and their clinical potential for the treatment of this devastating cancer type. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Antonio J Montero-Hidalgo
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
| | - Jesús M Pérez-Gómez
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
| | - Antonio J Martínez-Fuentes
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
| | - Enrique Gómez-Gómez
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- Urology Service, HURS/IMIBIC, Cordoba, 14004, Spain
| | - Manuel D Gahete
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
| | - Juan M Jiménez-Vacas
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
| | - Raúl M Luque
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Cordoba, 14004, Spain
- Department of Cell Biology, Physiology and Immunology, University of Cordoba, Cordoba, 14004, Spain
- Reina Sofia University Hospital (HURS), Cordoba, 14004, Spain
- CIBER Physiopathology of Obesity and Nutrition (CIBERobn), Cordoba, 14004, Spain
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5
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Hong Y, Kim I, Moon H, Lee J, Lertpatipanpong P, Ryu CH, Jung YS, Seok J, Kim Y, Ryu J, Baek SJ. Novel thrombospondin-1 transcript exhibits distinctive expression and activity in thyroid tumorigenesis. Oncogene 2023:10.1038/s41388-023-02692-9. [PMID: 37055552 DOI: 10.1038/s41388-023-02692-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 03/29/2023] [Accepted: 03/31/2023] [Indexed: 04/15/2023]
Abstract
Thrombospondin 1 (TSP1) is known for its cell-specific functions in cancer progression, such as proliferation and migration. It contains 22 exons that may potentially produce several different transcripts. Here, we identified TSP1V as a novel TSP1-splicing variant produced by intron retention (IR) in human thyroid cancer cells and tissues. We observed that TSP1V functionally inhibited tumorigenesis contrary to TSP1 wild-type, as identified in vivo and in vitro. These activities of TSP1V are caused by inhibiting phospho-Smad and phospho-focal adhesion kinase. Reverse transcription polymerase chain reaction and minigene experiments revealed that some phytochemicals/non-steroidal anti-inflammatory drugs enhanced IR. We further found that RNA-binding motif protein 5 (RBM5) suppressed IR induced by sulindac sulfide treatment. Additionally, sulindac sulfide reduced phospho-RBM5 levels in a time-dependent manner. Furthermore, trans-chalcone demethylated TSP1V, thereby preventing methyl-CpG-binding protein 2 binding to TSP1V gene. In addition, TSP1V levels were significantly lower in patients with differentiated thyroid carcinoma than in those with benign thyroid nodule, indicating its potential application as a diagnostic biomarker in tumor progression.
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Affiliation(s)
- Yukyung Hong
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Ilju Kim
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Hyunjin Moon
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Jaehak Lee
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Pattawika Lertpatipanpong
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea
| | - Chang Hwan Ryu
- Department of Otolaryngology-Head and Neck Surgery, Center for Thyroid Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea
| | - Yuh-Seog Jung
- Department of Otolaryngology-Head and Neck Surgery, Center for Thyroid Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea
| | - Jungirl Seok
- Department of Otolaryngology-Head and Neck Surgery, Center for Thyroid Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea
| | - Yonghwan Kim
- Department of Biological Sciences, Research Institute of Women's Health and Digital Humanity Center, Sookmyung Women's University, Seoul, 04310, Korea
| | - Junsun Ryu
- Department of Otolaryngology-Head and Neck Surgery, Center for Thyroid Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Korea.
| | - Seung Joon Baek
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, Korea.
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6
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Abstract
Dysregulated RNA splicing is a molecular feature that characterizes almost all tumour types. Cancer-associated splicing alterations arise from both recurrent mutations and altered expression of trans-acting factors governing splicing catalysis and regulation. Cancer-associated splicing dysregulation can promote tumorigenesis via diverse mechanisms, contributing to increased cell proliferation, decreased apoptosis, enhanced migration and metastatic potential, resistance to chemotherapy and evasion of immune surveillance. Recent studies have identified specific cancer-associated isoforms that play critical roles in cancer cell transformation and growth and demonstrated the therapeutic benefits of correcting or otherwise antagonizing such cancer-associated mRNA isoforms. Clinical-grade small molecules that modulate or inhibit RNA splicing have similarly been developed as promising anticancer therapeutics. Here, we review splicing alterations characteristic of cancer cell transcriptomes, dysregulated splicing's contributions to tumour initiation and progression, and existing and emerging approaches for targeting splicing for cancer therapy. Finally, we discuss the outstanding questions and challenges that must be addressed to translate these findings into the clinic.
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Affiliation(s)
- Robert K Bradley
- Computational Biology Program, Public Health Sciences Division and Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA.
| | - Olga Anczuków
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, USA.
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT, USA.
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7
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Xu XC, He S, Zhou YQ, Liu CJ, Liu SQ, Peng W, Liu YX, Wei PP, Bei JX, Luo CL. RNA-binding motif protein RBM47 promotes tumorigenesis in nasopharyngeal carcinoma through multiple pathways. J Genet Genomics 2021; 48:595-605. [PMID: 34274258 DOI: 10.1016/j.jgg.2021.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 12/13/2022]
Abstract
RNA binding motif proteins (RBMs) have been widely implicated in the tumorigenesis of multiple human cancers but scarcely studied in nasopharyngeal carcinoma (NPC). Here, we compare the mRNA levels of 29 RBMs between 87 NPC and 10 control samples. We find that RBM47 is frequently upregulated in NPC specimens, and its high expression is associated with the poor prognosis of patients with NPC. Biological experiments show that RBM47 plays an oncogenic role in NPC cells. Mechanically, RBM47 binds to the promoter and regulates the transcription of BCAT1, and its overexpression partially rescues the inhibitory effects of RBM47-knockdown on NPC cells. Moreover, transcriptome analysis reveals that RBM47 regulates alternative splicing of pre-mRNA, including those cancer-related, to a large extent in NPC cells. Furthermore, RBM47 binds to hnRNPM and cooperatively regulates multiple splicing events in NPC cells. In addition, we find that knockdown of hnRNPM inhibits proliferation and migration of NPC cells. Our study, taken together, shows that RBM47 promotes the progression of NPC through multiple pathways, acting as a transcriptional factor and a modulator of alternative splicing in cooperation with hnRNPM. Our study also highlights that RBM47 and hnRNPM could be prognostic factors and potential therapeutic targets for NPC.
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Affiliation(s)
- Xiao-Chen Xu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Shuai He
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Ya-Qing Zhou
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Chu-Jun Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Shu-Qiang Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Wan Peng
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Yu-Xiang Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Pan-Pan Wei
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Jin-Xin Bei
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China; Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou 510060, PR China; Department of Medical Oncology, National Cancer Centre of Singapore, Singapore 169610, Singapore
| | - Chun-Ling Luo
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China.
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8
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Cao Y, Di X, Zhang Q, Li R, Wang K. RBM10 Regulates Tumor Apoptosis, Proliferation, and Metastasis. Front Oncol 2021; 11:603932. [PMID: 33718153 PMCID: PMC7943715 DOI: 10.3389/fonc.2021.603932] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 01/12/2021] [Indexed: 12/15/2022] Open
Abstract
The RNA-binding motif protein 10 (RBM10) is involved in alternative splicing and modifies mRNA post-transcriptionally. RBM10 is abnormally expressed in the lung, breast, and colorectal cancer, female genital tumors, osteosarcoma, and other malignant tumors. It can inhibit proliferation, promote apoptosis, and inhibit invasion and metastasis. RBM10 has long been considered a tumor suppressor because it promotes apoptosis through the regulation of the MDM2-p53 negative feedback loop, Bcl-2, Bax, and other apoptotic proteins and inhibits proliferation through the Notch signaling and rap1a/Akt/CREB pathways. However, it has been recently demonstrated that RBM10 can also promote cancer. Given these different views, it is necessary to summarize the research progress of RBM10 in various fields to reasonably analyze the underlying molecular mechanisms, and provide new ideas and directions for the clinical research of RBM10 in various cancer types. In this review, we provide a new perspective on the reasons for these opposing effects on cancer biology, molecular mechanisms, research progress, and clinical value of RBM10.
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Affiliation(s)
- Yingshu Cao
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Xin Di
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Qinghua Zhang
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
| | - Ranwei Li
- Department of Urinary Surgery, The Second Hospital of Jilin University, Changchun, China
| | - Ke Wang
- Department of Respiratory Medicine, The Second Hospital of Jilin University, Changchun, China
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Bentata M, Morgenstern G, Nevo Y, Kay G, Granit Mizrahi A, Temper M, Maimon O, Monas L, Basheer R, Ben-Hur A, Peretz T, Salton M. Splicing Factor Transcript Abundance in Saliva as a Diagnostic Tool for Breast Cancer. Genes (Basel) 2020; 11:genes11080880. [PMID: 32756364 PMCID: PMC7463790 DOI: 10.3390/genes11080880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/27/2020] [Accepted: 07/30/2020] [Indexed: 11/16/2022] Open
Abstract
Breast cancer is the second leading cause of death in women above 60 years in the US. Screening mammography is recommended for women above 50 years; however, 22% of breast cancer cases are diagnosed in women below this age. We set out to develop a test based on the detection of cell-free RNA from saliva. To this end, we sequenced RNA from a pool of ten women. The 1254 transcripts identified were enriched for genes with an annotation of alternative pre-mRNA splicing. Pre-mRNA splicing is a tightly regulated process and its misregulation in cancer cells promotes the formation of cancer-driving isoforms. For these reasons, we chose to focus on splicing factors as biomarkers for the early detection of breast cancer. We found that the level of the splicing factors is unique to each woman and consistent in the same woman at different time points. Next, we extracted RNA from 36 healthy subjects and 31 breast cancer patients. Recording the mRNA level of seven splicing factors in these samples demonstrated that the combination of all these factors is different in the two groups (p value = 0.005). Our results demonstrate a differential abundance of splicing factor mRNA in the saliva of breast cancer patients.
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Affiliation(s)
- Mercedes Bentata
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (M.B.); (G.M.); (G.K.)
| | - Guy Morgenstern
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (M.B.); (G.M.); (G.K.)
| | - Yuval Nevo
- Info-CORE, Bioinformatics Unit of the I-CORE at the Hebrew University of Jerusalem and Hadassah Medical Center, Jerusalem 9112102, Israel;
| | - Gillian Kay
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (M.B.); (G.M.); (G.K.)
| | - Avital Granit Mizrahi
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Mark Temper
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Ofra Maimon
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Liza Monas
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Reham Basheer
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Asa Ben-Hur
- Department of Computer Science, Colorado State University, Fort Collins, CO 80523, USA;
| | - Tamar Peretz
- Sharett Institute of Oncology, Hadassah-Hebrew University Medical Center, Hebrew University Medical School, Jerusalem 9112102, Israel; (A.G.M.); (M.T.); (O.M.); (L.M.); (R.B.); (T.P.)
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; (M.B.); (G.M.); (G.K.)
- Correspondence:
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10
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Rahman MA, Nasrin F, Bhattacharjee S, Nandi S. Hallmarks of Splicing Defects in Cancer: Clinical Applications in the Era of Personalized Medicine. Cancers (Basel) 2020; 12:cancers12061381. [PMID: 32481522 PMCID: PMC7352608 DOI: 10.3390/cancers12061381] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/25/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing promotes proteome diversity by using limited number of genes, a key control point of gene expression. Splicing is carried out by large macromolecular machineries, called spliceosome, composed of small RNAs and proteins. Alternative splicing is regulated by splicing regulatory cis-elements in RNA and trans-acting splicing factors that are often tightly regulated in a tissue-specific and developmental stage-specific manner. The biogenesis of ribonucleoprotein (RNP) complexes is strictly regulated to ensure that correct complements of RNA and proteins are coordinated in the right cell at the right time to support physiological functions. Any perturbations that impair formation of functional spliceosomes by disrupting the cis-elements, or by compromising RNA-binding or function of trans-factors can be deleterious to cells and result in pathological consequences. The recent discovery of oncogenic mutations in splicing factors, and growing evidence of the perturbed splicing in multiple types of cancer, underscores RNA processing defects as a critical driver of oncogenesis. These findings have resulted in a growing interest in targeting RNA splicing as a therapeutic approach for cancer treatment. This review summarizes our current understanding of splicing alterations in cancer, recent therapeutic efforts targeting splicing defects in cancer, and future potentials to develop novel cancer therapies.
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11
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Conformational Dynamics from Ambiguous Zinc Coordination in the RanBP2-Type Zinc Finger of RBM5. J Mol Biol 2020; 432:4127-4138. [PMID: 32450081 DOI: 10.1016/j.jmb.2020.05.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/17/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
Abstract
The multi-domain RNA binding protein RBM5 is a molecular signature of metastasis. RBM5 regulates alternative splicing of apoptotic genes including the cell death receptor Fas and the initiator Caspase-2. The RBM5 RanBP2-type zinc finger (Zf1) is known to specifically recognize single-stranded RNAs with high affinity. Here, we study the structure and conformational dynamics of the Zf1 zinc finger of human RBM5 using NMR. We show that the presence of a non-canonical cysteine in Zf1 kinetically destabilizes the protein. Metal-exchange kinetics show that mutation of the cysteine establishes high-affinity coordination of the zinc. Our data indicate that selection of such a structurally destabilizing mutation during the course of evolution could present an opportunity for functional adaptation of the protein.
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12
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Zhang YP, Liu KL, Wang YX, Yang Z, Han ZW, Lu BS, Qi JC, Yin YW, Teng ZH, Chang XL, Li JD, Xin H, Li W. Down-regulated RBM5 inhibits bladder cancer cell apoptosis by initiating an miR-432-5p/β-catenin feedback loop. FASEB J 2019; 33:10973-10985. [PMID: 31318608 DOI: 10.1096/fj.201900537r] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RNA-binding motif protein 5 (RBM5) acts as a tumor suppressor in various human cancers and presents with several important characteristics, such as the potentiation of apoptosis, inhibition of the cell cycle, and alternative splicing of Fas and caspase-2 precursor mRNA. However, its role in bladder urothelial carcinoma (BUC) remains unknown. In this study, we found that RBM5 expression was significantly down-regulated in BUC tissues when compared with the adjacent nontumor tissues. The down-regulation of RBM5 activates β-catenin, which binds to the T-cell factor/lymphocyte enhancer factor element of the miR-432-5p promoter and elevates the expression of miR-432-5p in bladder cancer cells. The up-regulated miR-432-5p directly targets 3'-UTR and depresses RBM5 expression. Thus, RBM5-miR-432-5p-β-catenin forms a feedback loop in regulating bladder cancer cell apoptosis. Our findings provide evidence that the regulatory feedback loop among RBM5, miR-432-5p, and Wnt-β-catenin is responsible for the progress of bladder cancer cells.-Zhang, Y.-P., Liu, K.-L., Wang, Y.-X., Yang, Z., Han, Z.-W., Lu, B.-S., Qi, J.-C., Yin, Y.-W., Teng, Z.-H., Chang, X.-L., Li, J.-D., Xin, H., Li, W. Down-regulated RBM5 inhibits bladder cancer cell apoptosis by initiating an miR-432-5p/β-catenin feedback loop.
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Affiliation(s)
- Yan-Ping Zhang
- Department of Obstetrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China.,Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Kai-Long Liu
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Ya-Xuan Wang
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhan Yang
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhen-Wei Han
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Bao-Sai Lu
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jin-Chun Qi
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Yue-Wei Yin
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhi-Hai Teng
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xue-Liang Chang
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Jing-Dong Li
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Hong Xin
- Department of Obstetrics, The Second Hospital of Hebei Medical University, Shijiazhuang, China
| | - Wei Li
- Department of Urology, The Second Hospital of Hebei Medical University, Shijiazhuang, China
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13
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Duan B, Hu X, Fan M, Xiong X, Han L, Wang Z, Tong D, Liu L, Wang X, Li W, Yang J, Huang C. RNA-Binding Motif Protein 6 is a Candidate Serum Biomarker for Pancreatic Cancer. Proteomics Clin Appl 2019; 13:e1900048. [PMID: 31207145 DOI: 10.1002/prca.201900048] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 05/26/2019] [Indexed: 12/24/2022]
Abstract
PURPOSE Early diagnosis is crucial to improve outcomes for pancreatic cancer patients (PC). The present study is designed to identify differently expressed peptides involved in PC as potential biomarkers. EXPERIMENTAL DESIGN The serum proteome of 22 PC patients, 12 pancreatitis patients (PP), and 45 healthy controls (HC) are analyzed using magnetic bead-based weak cation exchange (MB-WCX) and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Next, a supervised neural network (SNN) algorithm model is established by ClinProTools and the candidate biomarker identified using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Finally, the candidate biomarker is validated in tissue samples. RESULTS The SNN algorithm model discriminates PC from HC with 92.97% sensitivity and 94.55% specificity. Seventy-six differentially expressed peptides are identified, seven of which are significantly different among PC, PP, and HC (p < 0.05). Only one peak (m/z: 1466.99) tends to be upregulated in samples from HC, PP, and PC, which is identified as region of RNA-binding motif protein 6 (RBM6). In subsequent tissue analysis, it is verified that RBM6 expression is significantly higher in PC tissues than paracancerous tissue. CONCLUSIONS AND CLINICAL RELEVANCE The results indicate that RBM6 might serve as a candidate diagnostic biomarker for PC. CLINICAL RELEVANCE Methods used in this study could generate serum peptidome profiles of PC, PP, and HC, and present an approach to identify potential biomarkers for diagnosis of this malignancy.
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Affiliation(s)
- Baojun Duan
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China.,Department of Medical Oncology of Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
| | - Xiaoyan Hu
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Meiyang Fan
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Xiaofan Xiong
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Lin Han
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Zheng Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Dongdong Tong
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Liying Liu
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Xiaofei Wang
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Wensheng Li
- Department of Pathology of Shaanxi Provincial People's Hospital, Xi'an, 710068, Shaanxi, China
| | - Juan Yang
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
| | - Chen Huang
- Key Laboratory of Environment and Disease-Related Gene, Ministry of Education/Department of Cell Biology and Genetics, School of Basic Medical Sciences, Xi'an Jiaotong University, Health Science Center, Xi'an, 710061, Shaanxi, China
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14
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Sun X, Jia M, Sun W, Feng L, Gu C, Wu T. Functional role of RBM10 in lung adenocarcinoma proliferation. Int J Oncol 2019; 54:467-478. [PMID: 30483773 PMCID: PMC6317669 DOI: 10.3892/ijo.2018.4643] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 10/23/2018] [Indexed: 12/20/2022] Open
Abstract
Lung cancer is one of the most common causes of morbidity and mortality among malignant tumors worldwide. The poor prognosis of patients with lung adenocarcinomas is primarily due to its strong ability to invade and metastasize. Recent research has indicated that RNA‑binding protein 10 (RBM10) is mutated in lung adenocarcinoma, and is closely associated with tumor proliferation and apoptosis; however, the precise role of RBM10 in lung adenocarcinoma remains unclear. Our preliminary experiments (unpublished data) revealed that RBM10 expression was upregulated in lung adenocarcinoma cell lines and tissues. In this study, we first detected the protein expression level of RBM10 in lung adenocarcinoma cells and tissues, and we then examined the effects of RBM10 overexpression and downregulation (via small interfering RNA) on the proliferation and apoptosis of stable lung adenocarcinoma cells, along with its possible mechanisms of action. We also used clinical samples of lung adenocarcinomas to verify our results. We found that RBM10 protein was overexpressed in lung adenocarcinoma cells and tissues, and it reduced p53 expression (as detected by immunofluorescence assay and western blot analysis) in A549 cells and inhibited apoptosis (as shown by flow cytometric assay). RBM10 also promoted cell growth and proliferation in vitro and increased cell migration in a cell wound scratch assay. Furthermore, we found that RBM10 activated key proliferative signaling pathways [such as the epidermal growth factor receptor (EGFR), mitogen‑activated protein kinase (MAPK) and phosphoinositide 3‑kinase (PI3K)‑AKT pathways] and inhibited apoptotic pathways. In addition, we demonstrated that a high expression of RBM10 protein in patient tissue samples was associated with a shorter overall survival time and a poor prognosis. On the whole, the findings of this study indicate that RBM10 may function as an oncogene in lung cancer, and may thus prove to be a novel therapeutic target for the prophylaxis and treatment of lung adenocarcinomas.
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Affiliation(s)
| | | | - Wei Sun
- Department of Respiratory Medicine
| | | | - Chundong Gu
- Department of Thoracic Surgery, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116011, P.R. China
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15
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Xu Y, Su Z, Li J, Wang Q, Meng G, Zhang Y, Yang W, Zhang J, Gao P. Role of RNA-binding protein 5 in the diagnosis and chemotherapeutic response of lung cancer. Oncol Lett 2018; 17:2013-2019. [PMID: 30675268 DOI: 10.3892/ol.2018.9818] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 10/04/2018] [Indexed: 01/16/2023] Open
Abstract
Lung cancer remains one of the leading causes of cancer-associated mortality in the world. Lung carcinogenesis is frequently associated with deletions or the loss of heterozygosity at the critical chromosomal region 3p21.3, where RNA-binding protein 5 (RBM5) is localized. RBM5 regulates cell growth, cell cycle progression and apoptosis in cell homeostasis. In the lungs, altered RBM5 protein expression leads to alterations in cell growth and apoptosis, with subsequent lung pathogenesis and varied responses to treatment in patients with lung cancer. Detection of RBM5 expression may be a tumor marker for diagnosis, prediction and treatment response in lung cancer, and may be developed as a potential therapeutic target for drug resistant lung cancer. This review discusses the most recent progress on the role of RBM5 in lung cancer.
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Affiliation(s)
- Yanling Xu
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China.,Department of Geriatrics and General Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Zhenzhong Su
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Junyao Li
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Qi Wang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Guangping Meng
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Yu Zhang
- Department of Geriatrics and General Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Wen Yang
- Department of Geriatrics and General Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Jie Zhang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Peng Gao
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
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16
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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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17
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Jamsai D, Watkins DN, O'Connor AE, Merriner DJ, Gursoy S, Bird AD, Kumar B, Miller A, Cole TJ, Jenkins BJ, O'Bryan MK. In vivo evidence that RBM5 is a tumour suppressor in the lung. Sci Rep 2017; 7:16323. [PMID: 29176597 PMCID: PMC5701194 DOI: 10.1038/s41598-017-15874-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 11/03/2017] [Indexed: 01/04/2023] Open
Abstract
Cigarette smoking is undoubtedly a risk factor for lung cancer. Moreover, smokers with genetic mutations on chromosome 3p21.3, a region frequently deleted in cancer and notably in lung cancer, have a dramatically higher risk of aggressive lung cancer. The RNA binding motif 5 (RBM5) is one of the component genes in the 3p21.3 tumour suppressor region. Studies using human cancer specimens and cell lines suggest a role for RBM5 as a tumour suppressor. Here we demonstrate, for the first time, an in vivo role for RBM5 as a tumour suppressor in the mouse lung. We generated Rbm5 loss-of-function mice and exposed them to a tobacco carcinogen NNK. Upon exposure to NNK, Rbm5 loss-of-function mice developed lung cancer at similar rates to wild type mice. As tumourigenesis progressed, however, reduced Rbm5 expression lead to significantly more aggressive lung cancer i.e. increased adenocarcinoma nodule numbers and tumour size. Our data provide in vivo evidence that reduced RBM5 function, as occurs in a large number of patients, coupled with exposure to tobacco carcinogens is a risk factor for an aggressive lung cancer phenotype. These data suggest that RBM5 loss-of-function likely underpins at least part of the pro-tumourigenic consequences of 3p21.3 deletion in humans.
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Affiliation(s)
- Duangporn Jamsai
- The School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia.,The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia
| | - D Neil Watkins
- Cancer Developmental Biology Group, The Garvan Institute of Medical Research, 384 Victoria St, Darlinghurst, Sydney, NSW 2010, Australia
| | - Anne E O'Connor
- The School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia.,The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia
| | - D Jo Merriner
- The School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia.,The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia
| | - Selen Gursoy
- The School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia.,The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia
| | - Anthony D Bird
- The Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia
| | - Beena Kumar
- Department of Anatomical Pathology, Monash Medical Centre, Monash Health, 246 Clayton Rd, Clayton, Victoria 3168, Australia
| | - Alistair Miller
- General and Respiratory Medicine, Monash Medical Centre, Monash Health, 246 Clayton Rd, Clayton, Victoria 3168, Australia
| | - Timothy J Cole
- The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.,The Department of Biochemistry and Molecular Biology, Monash University, 19 Innovation Walk, Clayton, Victoria 3800, Australia
| | - Brendan J Jenkins
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Monash University, 27-31 Wright St, Clayton, Victoria 3168, Australia
| | - Moira K O'Bryan
- The School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, Victoria, 3800, Australia. .,The Development and Stem Cells Program of Monash Biomedicine Discovery Institute, 19 Innovation Walk, Clayton, Victoria, 3800, Australia.
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18
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Sutherland LC, Thibault P, Durand M, Lapointe E, Knee JM, Beauvais A, Kalatskaya I, Hunt SC, Loiselle JJ, Roy JG, Tessier SJ, Ybazeta G, Stein L, Kothary R, Klinck R, Chabot B. Splicing arrays reveal novel RBM10 targets, including SMN2 pre-mRNA. BMC Mol Biol 2017; 18:19. [PMID: 28728573 PMCID: PMC5520337 DOI: 10.1186/s12867-017-0096-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 07/14/2017] [Indexed: 12/18/2022] Open
Abstract
Background RBM10 is an RNA binding protein involved in message stabilization and alternative splicing regulation. The objective of the research described herein was to identify novel targets of RBM10-regulated splicing. To accomplish this, we downregulated RBM10 in human cell lines, using small interfering RNAs, then monitored alternative splicing, using a reverse transcription-PCR screening platform. Results RBM10 knockdown (KD) provoked alterations in splicing events in 10–20% of the pre-mRNAs, most of which had not been previously identified as RBM10 targets. Hierarchical clustering of the genes affected by RBM10 KD revealed good conservation of alternative exon inclusion or exclusion across cell lines. Pathway annotation showed RAS signaling to be most affected by RBM10 KD. Of particular interest was the finding that splicing of SMN pre-mRNA, encoding the survival of motor neuron (SMN) protein, was influenced by RBM10 KD. Inhibition of RBM10 resulted in preferential expression of the full-length, exon 7 retaining, SMN transcript in four cancer cell lines and one normal skin fibroblast cell line. SMN protein is expressed from two genes, SMN1 and SMN2, but the SMN1 gene is homozygously disrupted in people with spinal muscular atrophy; as a consequence, all of the SMN that is expressed in people with this disease is from the SMN2 gene. Expression analyses using primary fibroblasts from control, carrier and spinal muscle atrophy donors demonstrated that RBM10 KD resulted in preferential expression of the full-length, exon 7 retaining, SMN2 transcript. At the protein level, upregulation of the full-length SMN2 was also observed. Re-expression of RBM10, in a stable RBM10 KD cancer cell line, correlated with a reversion of the KD effect, demonstrating specificity. Conclusion Our work has not only expanded the number of pre-mRNA targets for RBM10, but identified RBM10 as a novel regulator of SMN2 alternative inclusion. Electronic supplementary material The online version of this article (doi:10.1186/s12867-017-0096-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Leslie C Sutherland
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada. .,Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6, Canada. .,Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada.
| | - Philippe Thibault
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Mathieu Durand
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Elvy Lapointe
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Jose M Knee
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Ariane Beauvais
- Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Irina Kalatskaya
- Ontario Institute for Cancer Research, MaRS Centre, Toronto, ON, M5G 0A3, Canada
| | - Sarah C Hunt
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Julie J Loiselle
- Biomolecular Sciences Program, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Justin G Roy
- Department of Chemistry and Biochemistry, Laurentian University, Sudbury, ON, P3E 2C6, Canada
| | - Sarah J Tessier
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Gustavo Ybazeta
- Health Sciences North Research Institute, Sudbury, ON, P3E 5J1, Canada
| | - Lincoln Stein
- Ontario Institute for Cancer Research, MaRS Centre, Toronto, ON, M5G 0A3, Canada
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada.,Departments of Medicine and of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Roscoe Klinck
- RNomics Platform of Université de Sherbrooke, Sherbrooke, QC, Canada.,Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Benoit Chabot
- Département de Microbiologie et d'infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada
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19
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Guan G, Li R, Tang W, Liu T, Su Z, Wang Y, Tan J, Jiang S, Wang K. Expression of RNA-binding motif 10 is associated with advanced tumor stage and malignant behaviors of lung adenocarcinoma cancer cells. Tumour Biol 2017; 39:1010428317691740. [PMID: 28347232 DOI: 10.1177/1010428317691740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
This study assessed RNA-binding motif 10 expression in lung adenocarcinoma tissues and examined the role and mechanism of RNA-binding motif 10 in the regulation of lung adenocarcinoma malignancy. Lung adenocarcinoma and corresponding adjacent non-tumor lung tissues from 41 patients were subjected to reverse transcription-polymerase chain reaction and Western blot assessment to detect RNA-binding motif 10 expression. Recombinant lentivirus carrying RNA-binding motif 10 complementary DNA was used to infect lung adenocarcinoma cell lines, A549 and H1299 cells. Complementary DNA microarray was used to profile RNA-binding motif 10–regulated genes. Levels of RNA-binding motif 10 messenger RNA and protein were significantly lower in lung adenocarcinoma tissues than those in paired non-tumor tissues (p < 0.001). Reduced RNA-binding motif 10 expression was found to be associated with an advanced tumor stage. RNA-binding motif 10 overexpression inhibited viability and colony formation capacity of lung adenocarcinoma cell lines and induced cell-cycle arrest at G0/G1 phase in A549 cells and at S phase in H1299 cells. Complementary DNA microarray analysis identified 304 upregulated and 386 downregulated genes induced by RNA-binding motif 10 overexpression, which may be involved in cancer, focal adhesion, peroxisome proliferator-activated receptor–regulated gene pathway, cytokine–cytokine receptor interaction, mitogen-activated protein kinase signaling, complement and coagulation cascades, platelet amyloid precursor protein pathway, extracellular matrix-receptor interaction, and small cell lung cancer–related genes. Expression of FGF2, EGFR, WNT5A, NF-κB, and RAP1A was downregulated, whereas expression of AKT2, BIRC3, and JUN was upregulated. RNA-binding motif 10 messenger RNA and protein were reduced in lung adenocarcinoma tissues, and RNA-binding motif 10 overexpression inhibited lung adenocarcinoma cancer cell malignant behavior in vitro. Molecularly, RNA-binding motif 10 regulates many gene pathways involving in the tumor development or progression.
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Affiliation(s)
- Guofang Guan
- Department of Otolaryngology, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Ranwei Li
- Department of Urinary Surgery, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Wenfang Tang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Tiecheng Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Zhenzhong Su
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Yan Wang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Jingjin Tan
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Shan Jiang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
| | - Ke Wang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China
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20
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Mourão A, Bonnal S, Soni K, Warner L, Bordonné R, Valcárcel J, Sattler M. Structural basis for the recognition of spliceosomal SmN/B/B' proteins by the RBM5 OCRE domain in splicing regulation. eLife 2016; 5:14707. [PMID: 27894420 PMCID: PMC5127646 DOI: 10.7554/elife.14707] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 11/01/2016] [Indexed: 12/18/2022] Open
Abstract
The multi-domain splicing factor RBM5 regulates the balance between antagonistic isoforms of the apoptosis-control genes FAS/CD95, Caspase-2 and AID. An OCRE (OCtamer REpeat of aromatic residues) domain found in RBM5 is important for alternative splicing regulation and mediates interactions with components of the U4/U6.U5 tri-snRNP. We show that the RBM5 OCRE domain adopts a unique β–sheet fold. NMR and biochemical experiments demonstrate that the OCRE domain directly binds to the proline-rich C-terminal tail of the essential snRNP core proteins SmN/B/B’. The NMR structure of an OCRE-SmN peptide complex reveals a specific recognition of poly-proline helical motifs in SmN/B/B’. Mutation of conserved aromatic residues impairs binding to the Sm proteins in vitro and compromises RBM5-mediated alternative splicing regulation of FAS/CD95. Thus, RBM5 OCRE represents a poly-proline recognition domain that mediates critical interactions with the C-terminal tail of the spliceosomal SmN/B/B’ proteins in FAS/CD95 alternative splicing regulation. The information required to produce proteins is encoded within genes. In the first step of creating a protein, its gene is “transcribed” to form a pre-messenger RNA molecule (called pre-mRNA for short). Both the gene and the pre-mRNA contain regions called exons that code for protein, and regions called introns that do not. The pre-mRNA therefore undergoes a process called splicing to remove the introns and join the exons together into a final mRNA molecule that is “translated” to make the protein. Many pre-mRNAs can be spliced in several different ways to include different combinations of exons in the final mRNA molecule. This process of “alternative splicing” allows different versions of a protein to be produced from the same gene. Changes that alter the pattern of alternative splicing in a cell affect various cellular and developmental processes and have been linked to diseases such as cancer. The pre-mRNA transcribed from a gene called FAS can be alternatively spliced so that it either does or does not contain an exon that enables the protein to embed itself in the cell membrane. The protein produced from mRNA that includes this exon generates a cell response that leads to cell death. By contrast, protein produced from mRNA that lacks this exon is released from cells and promotes their survival. A splicing factor called RBM5 promotes the removal of this exon from FAS pre-mRNA. RBM5 binds to some of the proteins that make up the molecular machine that splices pre-mRNA molecules. Mourão, Bonnal, Soni, Warner et al. have now used a technique called nuclear magnetic resonance spectroscopy to solve the three-dimensional structure formed when RBM5 binds to one of these proteins, called SmN. Further experiments introduced specific mutations to the proteins to investigate their effects in human cells. This revealed that mutations that impaired the association between RBM5 and SmN compromised the activity of RBM5 to regulate the alternative splicing of FAS pre-mRNA molecules. Future research could examine how RBM5 associates with pre-mRNAs and other components of the splicing machinery, and investigate whether proteins that are closely related to RBM5 act in similar ways.
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Affiliation(s)
- André Mourão
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
| | - Sophie Bonnal
- Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Centre de Regulació Genòmica, Barcelona, Spain
| | - Komal Soni
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
| | - Lisa Warner
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Université de Montpellier, Montpellier, France
| | - Juan Valcárcel
- Barcelona Institute of Science and Technology and Universitat Pompeu Fabra, Centre de Regulació Genòmica, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich, Department Chemie, Technische Universität München, Garching, Germany
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Yoshimi A, Abdel-Wahab O. Molecular Pathways: Understanding and Targeting Mutant Spliceosomal Proteins. Clin Cancer Res 2016; 23:336-341. [PMID: 27836865 DOI: 10.1158/1078-0432.ccr-16-0131] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 10/09/2016] [Accepted: 10/11/2016] [Indexed: 02/06/2023]
Abstract
Splicing of precursor messenger RNA is a critical step in regulating gene expression, and major advances are being made in understanding the composition and structure of the enzymatic complex that performs splicing, which is termed the "spliceosome." In parallel, there has been increased appreciation for diverse mechanisms by which alterations in splicing contribute to cancer pathogenesis. Key among these include change-of-function mutations in genes encoding spliceosomal proteins. Such mutations are among the most common genetic alterations in myeloid and lymphoid leukemias, making efforts to therapeutically target cells bearing these mutations critical. To this end, recent studies have clarified that pharmacologic modulation of splicing may be preferentially lethal for cells bearing spliceosomal mutations and may also have a role in the therapy of MYC-driven cancers. This has culminated in the initiation of a clinical trial of a novel oral spliceosome modulatory compound targeting the SF3B complex, and several novel alternative approaches to target splicing are in development as reviewed here. There is now, therefore, a great need to understand the mechanistic basis of altered spliceosomal function in cancers and to study the effects of spliceosomal modulatory compounds in preclinical settings and in well-designed clinical trials. Clin Cancer Res; 23(2); 336-41. ©2016 AACR.
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Affiliation(s)
- Akihide Yoshimi
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, New York
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, New York, New York.
- Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
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22
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Abstract
Tumor-associated alterations in RNA splicing result either from mutations in splicing-regulatory elements or changes in components of the splicing machinery. This review summarizes our current understanding of the role of splicing-factor alterations in human cancers. We describe splicing-factor alterations detected in human tumors and the resulting changes in splicing, highlighting cell-type-specific similarities and differences. We review the mechanisms of splicing-factor regulation in normal and cancer cells. Finally, we summarize recent efforts to develop novel cancer therapies, based on targeting either the oncogenic splicing events or their upstream splicing regulators.
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Affiliation(s)
- Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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23
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Abstract
The recent genomic characterization of cancers has revealed recurrent somatic point mutations and copy number changes affecting genes encoding RNA splicing factors. Initial studies of these 'spliceosomal mutations' suggest that the proteins bearing these mutations exhibit altered splice site and/or exon recognition preferences relative to their wild-type counterparts, resulting in cancer-specific mis-splicing. Such changes in the splicing machinery may create novel vulnerabilities in cancer cells that can be therapeutically exploited using compounds that can influence the splicing process. Further studies to dissect the biochemical, genomic and biological effects of spliceosomal mutations are crucial for the development of cancer therapies targeted at these mutations.
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Affiliation(s)
- Heidi Dvinge
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Eunhee Kim
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
- Leukemia Service, Dept. of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Robert K. Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
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Overexpression of RBM5 induces autophagy in human lung adenocarcinoma cells. World J Surg Oncol 2016; 14:57. [PMID: 26923134 PMCID: PMC4770605 DOI: 10.1186/s12957-016-0815-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 02/17/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Dysfunctions in autophagy and apoptosis are closely interacted and play an important role in cancer development. RNA binding motif 5 (RBM5) is a tumor suppressor gene, which inhibits tumor cells' growth and enhances chemosensitivity through inducing apoptosis in our previous studies. In this study, we investigated the relationship between RBM5 overexpression and autophagy in human lung adenocarcinoma cells. METHODS Human lung adenocarcinoma cancer (A549) cells were cultured in vitro and were transiently transfected with a RBM5 expressing plasmid (GV287-RBM5) or plasmid with scrambled control sequence. RBM5 expression was determined by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot. Intracellular LC-3 I/II, Beclin-1, lysosome associated membrane protein-1 (LAMP1), Bcl-2, and NF-κB/p65 protein levels were detected by Western blot. Chemical staining with monodansylcadaverine (MDC) and acridine orange (AO) was applied to detect acidic vesicular organelles (AVOs). The ultrastructure changes were observed under transmission electron microscope (TEM). Then, transplanted tumor models of A549 cells on BALB/c nude mice were established and treated with the recombinant plasmids carried by attenuated Salmonella to induce RBM5 overexpression in tumor tissues. RBM5, LC-3, LAMP1, and Beclin1 expression was determined by immunohistochemistry staining in plasmids-treated A549 xenografts. RESULTS Our study demonstrated that overexpression of RBM5 caused an increase in the autophagy-related proteins including LC3-I, LC3-II, LC3-II/LC3-I ratio, Beclin1, and LAMP1 in A549 cells. A large number of autophagosomes with double-membrane structure and AVOs were detected in the cytoplasm of A549 cells transfected with GV287-RBM5 at 24 h. We observed that the protein level of NF-κB/P65 was increased and the protein level of Bcl-2 decreased by RBM5 overexpression. Furthermore, treatment with an autophagy inhibitor, 3-MA, enhanced RBM5-induced cell death and chemosensitivity in A549 cells. Furthermore, we successfully established the lung adenocarcinoma animal model using A549 cells. Overexpression of RBM5 enhanced the LC-3, LAMP1, and Beclin1 expression in the A549 xenografts. CONCLUSIONS Our findings showed for the first time that RBM5 overexpression induced autophagy in human lung adenocarcinoma cells, which might be driven by upregulation of Beclin1, NF-κB/P65, and downregulation of Bcl-2. RBM5-enhanced autophagy acts in a cytoprotective way and inhibition of autophagy may improve the anti-tumor efficacy of RBM5 in lung cancer.
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25
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Markus MA, Yang YHJ, Morris BJ. Transcriptome-wide targets of alternative splicing by RBM4 and possible role in cancer. Genomics 2016; 107:138-44. [PMID: 26898347 DOI: 10.1016/j.ygeno.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Revised: 01/22/2016] [Accepted: 02/16/2016] [Indexed: 10/25/2022]
Abstract
This study determined transcriptome-wide targets of the splicing factor RBM4 using Affymetrix GeneChip(®) Human Exon 1.0 ST Arrays and HeLa cells treated with RBM4-specific siRNA. This revealed 238 transcripts that were targeted for alternative splicing. Cross-linking and immunoprecipitation experiments identified 945 RBM4 targets in mouse HEK293 cells, 39% of which were ascribed to "alternative splicing" by in silico pathway analysis. Mouse embryonic stem cells transfected with Rbm4 siRNA hairpins exhibited reduced colony numbers and size consistent with involvement of RBM4 in cell proliferation. RBM4 cDNA probing of a cancer cDNA array involving 18 different tumor types from 13 different tissues and matching normal tissue found overexpression of RBM4 mRNA (p<0.01) in cervical, breast, lung, colon, ovarian and rectal cancers. Many RBM4 targets we identified have been implicated in these cancers. In conclusion, our findings reveal transcriptome-wide targets of RBM4 and point to potential cancer-related targets and mechanisms that may involve RBM4.
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Affiliation(s)
- M Andrea Markus
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia.
| | - Yee Hwa J Yang
- School of Mathematics and Statistics, The University of Sydney, Sydney, New South Wales, Australia.
| | - Brian J Morris
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia.
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Ozuemba B, Masilamani TJ, Loiselle JJ, Koenderink B, Vanderbeck KA, Knee J, Larivière C, Sutherland LC. Co- and post-transcriptional regulation of Rbm5 and Rbm10 in mouse cells as evidenced by tissue-specific, developmental and disease-associated variation of splice variant and protein expression levels. Gene 2016; 580:26-36. [PMID: 26784654 DOI: 10.1016/j.gene.2015.12.070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/31/2015] [Indexed: 01/09/2023]
Abstract
BACKGROUND Expression and function of the two RNA binding proteins and regulators of alternative splicing, RBM5 and RBM10, have largely been studied in human tissue and cell lines. The objective of the study described herein was to examine their expression in mouse tissue, in order to lay the framework for comprehensive functional studies using mouse models. METHODS All RNA variants of Rbm5 and Rbm10 were examined in a range of normal primary mouse tissues. RNA and protein were examined in differentiating C2C12 myoblasts and in denervated and dystonin-deficient mouse skeletal muscle. RESULTS All Rbm5 and Rbm10 variants examined were expressed in all mouse tissues and cell lines. In general, Rbm5 and Rbm10 RNA expression was higher in brain than in skin. RNA expression levels were more varied between cardiac and skeletal muscle, depending on the splice variant: for instance, Rbm10v1 RNA was higher in skeletal than cardiac muscle, whereas Rbm10v3 RNA was higher in cardiac than skeletal muscle. In mouse brain, cardiac and skeletal muscle, RNA encoding an approximately 17kDa potential paralogue of a small human RBM10 isoform was detected, and the protein observed in myoblasts and myotubes. Expression of Rbm5 and Rbm10 RNA remained constant during C2C12 myogenesis, but protein levels significantly decreased. In two muscle disease models, neither Rbm10 nor Rbm5 showed significant transcriptional changes, although significant specific alternative splicing changes of Rbm5 pre-mRNA were observed. Increased RBM10 protein levels were observed following denervation. CONCLUSIONS The varied co-transcriptional and post-transcriptional regulation aspects of Rbm5 and Rbm10 expression associated with mouse tissues, myogenesis and muscle disease states suggest that a mouse model would be an interesting and useful model in which to study comprehensive functional aspects of RBM5 and RBM10.
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Affiliation(s)
| | - Twinkle J Masilamani
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Julie J Loiselle
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Benjamin Koenderink
- AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5J1, Canada
| | - Kaitlin A Vanderbeck
- School of Human Kinetics, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Jose Knee
- AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5J1, Canada
| | - Céline Larivière
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada; School of Human Kinetics, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Leslie C Sutherland
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada; AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5J1, Canada; Division of Medical Sciences, Northern Ontario School of Medicine, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada; Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada; Department of Medicine, Division of Medical Oncology, University of Ottawa, Ottawa, ON, Canada.
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27
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Lv XJ, Du YW, Hao YQ, Su ZZ, Zhang L, Zhao LJ, Zhang J. RNA-binding motif protein 5 inhibits the proliferation of cigarette smoke-transformed BEAS-2B cells through cell cycle arrest and apoptosis. Oncol Rep 2016; 35:2315-27. [PMID: 26782095 DOI: 10.3892/or.2016.4551] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 12/11/2015] [Indexed: 11/06/2022] Open
Abstract
Cigarette smoking has been shown to be the most significant risk factor for lung cancer. Recent studies have also indicated that RNA-binding motif protein 5 (RBM5) can modulate apoptosis and suppress tumor growth. The present study focused on the role of RBM5 in the regulation of cigarette smoke extract (CSE)-induced transformation of bronchial epithelial cells into the cancerous phenotype and its mechanism of action. Herein, we exposed normal BEAS-2B cells for 8 days to varying concentrations of CSE or dimethylsulfoxide (DMSO), followed by a recovery period of 2 weeks. Next, the RBM5 protein was overexpressed in these transformed BEAS-2B cells though lentiviral infection. Later, the morphological changes, cell proliferation, cell cycle, apoptosis, invasion and migration were assessed. In addition, we analyzed the role of RBM5 in xenograft growth. The expression of RBM5 along with the genes related to cell cycle regulation, apoptosis and invasion were also examined. Finally, our results revealed that BEAS-2B cells exposed to 100 µg/ml CSE acquired phenotypic changes and formed tumors in nude mice, indicative of their cancerous transformation and had reduced RBM5 expression. Subsequent overexpression of RBM5 in these cells significantly inhibited their proliferation, induced G1/S arrest, triggered apoptosis and inhibited their invasion and migration, including xenograft growth. Thus, we established an in vitro model of CSE-induced cancerous transformation and concluded that RBM5 overexpression inhibited the growth of these transformed cells through cell cycle arrest and induction of apoptosis. Therefore, our study suggests the importance of RBM5 in the pathogenesis of smoking-related cancer.
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Affiliation(s)
- Xue-Jiao Lv
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Yan-Wei Du
- Department of Pathology, College of Basic Medicine, Changchun University of Chinese Medicine, Changchun, Jilin 130117, P.R. China
| | - Yu-Qiu Hao
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Zhen-Zhong Su
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Lin Zhang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
| | - Li-Jing Zhao
- Department of Pathophysiology, College of Basic Medicine, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Jie Zhang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, P.R. China
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28
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Loiselle JJ, Tessier SJ, Sutherland LC. Post-transcriptional regulation of Rbm5 expression in undifferentiated H9c2 myoblasts. In Vitro Cell Dev Biol Anim 2015; 52:327-336. [PMID: 26659391 PMCID: PMC4833810 DOI: 10.1007/s11626-015-9976-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/04/2015] [Indexed: 12/20/2022]
Abstract
We previously examined the expression of Rbm5 during myoblast differentiation and found significantly more protein in the early stages of skeletal myoblast differentiation than during the later stages. We decided to determine if this elevated level was necessary for differentiation. Our hypothesis was that if high levels of Rbm5 protein expression were necessary for the initiation of skeletal myoblast differentiation, then inhibition of expression would prevent differentiation. Our long-term objective is to inhibit Rbm5 expression and examine the effect on H9c2 differentiation. Towards this end, stable knockdown clones and transient knockdown populations were generated. Expression analyses in H9c2 myoblasts demonstrated significant Rbm5 messenger RNA (mRNA) inhibition but, surprisingly, no effect on RBM5 protein levels. Expression of the Rbm5 paralogue Rbm10 was examined in order to (a) ensure no off-target knockdown effect, and (b) investigate any possible compensatory effects. RBM10 protein levels were found to be elevated, in both the clonal and transiently transfected populations. These results suggest that myoblast RBM5 expression is regulated by a process that includes RNA sequestration and/or controlled translation, and that (a) RBM5 function is compensated for by RBM10, and/or (b) RBM5 regulates RBM10 expression. We have developed a model to describe our findings, and suggest further experiments for testing its validity. Since upregulation of Rbm10 might compensate for downregulated Rbm5, and consequently might mask any potential knockdown effect, it could lead to incorrect conclusions regarding the importance of Rbm5 for differentiation. It is therefore imperative to determine how both RBM5 and RBM10 protein expression is regulated.
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Affiliation(s)
- Julie J Loiselle
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada. .,AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5J1, Canada.
| | - Sarah J Tessier
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada
| | - Leslie C Sutherland
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.,AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5J1, Canada.,Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.,Division of Medical Sciences, Northern Ontario School of Medicine, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.,Department of Medicine, Division of Medical Oncology, University of Ottawa, Ottawa, ON, Canada
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Silipo M, Gautrey H, Tyson-Capper A. Deregulation of splicing factors and breast cancer development. J Mol Cell Biol 2015; 7:388-401. [PMID: 25948865 DOI: 10.1093/jmcb/mjv027] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/24/2015] [Indexed: 11/13/2022] Open
Abstract
It is well known that many genes implicated in the development and progression of breast cancer undergo aberrant alternative splicing events to produce proteins with pro-cancer properties. These changes in alternative splicing can arise from mutations or single-nucleotide polymorphisms (SNPs) within the DNA sequences of cancer-related genes, which can strongly affect the activity of splicing factors and influence the splice site choice. However, it is important to note that absence of mutations is not sufficient to prevent misleading choices in splice site selection. There is now increasing evidence to demonstrate that the expression profile of ten splicing factors (including SRs and hnRNPs) and eight RNA-binding proteins changes in breast cancer cells compared with normal cells. These modifications strongly influence the alternative splicing pattern of many cancer-related genes despite the absence of any detrimental mutations within their DNA sequences. Thus, a comprehensive assessment of the splicing factor status in breast cancer is important to provide insights into the mechanisms that lead to breast cancer development and metastasis. Whilst most studies focus on mutations that affect alternative splicing in cancer-related genes, this review focuses on splicing factors and RNA-binding proteins that are themselves deregulated in breast cancer and implicated in cancer-related alternative splicing events.
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Affiliation(s)
- Marco Silipo
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Hannah Gautrey
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Alison Tyson-Capper
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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30
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Tessier SJ, Loiselle JJ, McBain A, Pullen C, Koenderink BW, Roy JG, Sutherland LC. Insight into the role of alternative splicing within the RBM10v1 exon 10 tandem donor site. BMC Res Notes 2015; 8:46. [PMID: 25889998 PMCID: PMC4336493 DOI: 10.1186/s13104-015-0983-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 01/15/2015] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND RBM10 is an RNA binding protein involved in the regulation of transcription, alternative splicing and message stabilization. Mutations in RBM10, which maps to the X chromosome, are associated with TARP syndrome, lung and pancreatic cancers. Two predominant isoforms of RBM10 exist, RBM10v1 and RBM10v2. Both variants have alternate isoforms that differ by one valine residue, at amino acid 354 (RBM10v1) or 277 (RBM10v2). It was recently observed that a novel point mutation at amino acid 354 of RBM10v1, replacing valine with glutamic acid, correlated with preferential expression of an exon 11 inclusion variant of the proliferation regulatory protein NUMB, which is upregulated in lung cancer. FINDINGS We demonstrate, using the GLC20 male-derived small cell lung cancer cell line - confirmed to have only one X chromosome - that the two (+/-) valine isoforms of RBM10v1 and RBM10v2 result from alternative splicing. Protein modeling of the RNA Recognition Motif (RRM) within which the alteration occurs, shows that the presence of valine inhibits the formation of one of the two α-helices associated with RRM tertiary structure, whereas the absence of valine supports the α-helical configuration. We then show 2-fold elevated expression of the transcripts encoding the minus valine RBM10v1 isoform in GLC20 cells, compared to those encoding the plus valine isoform. This expression correlates with preferential expression of the lung cancer-associated NUMB exon 11 inclusion variant. CONCLUSIONS Our observations suggest that the ability of RBM10v1 to regulate alternative splicing depends, at least in part, on a structural alteration within the second RRM domain, which influences whether RBM10v1 functions to support or repress splicing. A model is presented.
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Affiliation(s)
- Sarah J Tessier
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
| | - Julie J Loiselle
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
| | - Anne McBain
- Genetics Lab, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5 J1, Canada.
| | - Celine Pullen
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
| | | | - Justin G Roy
- Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
| | - Leslie C Sutherland
- Department of Biology, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
- Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
- AMRIC, Health Sciences North, 41 Ramsey Lake Road, Sudbury, ON, P3E 5 J1, Canada.
- Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
- Division of Medical Sciences, Northern Ontario School of Medicine, Laurentian University, 935 Ramsey Lake Road, Sudbury, ON, P3E 2C6, Canada.
- Department of Medicine, Division of Medical Oncology, University of Ottawa, Ottawa, ON, Canada.
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Hong J, Yuan Y, Wang J, Liao Y, Zou R, Zhu C, Li B, Liang Y, Huang P, Wang Z, Lin W, Zeng Y, Dai JL, Chung RT. Expression of variant isoforms of the tyrosine kinase SYK determines the prognosis of hepatocellular carcinoma. Cancer Res 2014; 74:1845-56. [PMID: 24477596 DOI: 10.1158/0008-5472.can-13-2104] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The spleen tyrosine kinase (SYK) has been reported as a novel biomarker for human hepatocellular carcinoma, but the functional contributions of its two isoforms SYK(L) and SYK(S) are undefined. In this study, we investigated their biologic functions and possible prognostic values in hepatocellular carcinoma. SYK(L) was downregulated in 38% of human specimens of hepatocellular carcinoma examined, whereas SYK(S) was detectable in 40% of these specimens but not in normal liver tissue samples without cirrhosis. SYK(S) expression correlated with pathologic parameters characteristic of tumor metastasis, including multiple tumors (P = 0.003) and vascular invasion (P = 0.001). Further, SYK(S) was specifically associated with epithelial-mesenchymal transition (EMT) in hepatocellular carcinoma specimens. Functional studies showed that SYK(S) promoted tumor growth, suppressed apoptosis, and induced EMT through the extracellular signal-regulated kinase pathway, countering the opposite effects of SYK(L). Patients with SYK(L(+)/S(-)) tumors exhibited longer overall survival and time to recurrence than those with SYK(L(-)/S(-)) or SYK(L(+)/S(+)) tumors (P < 0.001). Taken together, our findings showed that SYK(S) enhances invasion, whereas SYK(L) inhibits metastasis in hepatocellular carcinoma. We suggest that SYK(L) downregulation or SYK(S) elevation are strong predictors of poor survival in patients with hepatocellular carcinoma, indicative of a need for aggressive therapeutic intervention.
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Affiliation(s)
- Jian Hong
- Authors' Affiliations: State Key Laboratory of Oncology in South China; Department of Hepatobiliary Oncology, Sun Yat-sen University Cancer Center; Department of Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China; Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts; and Division of Pharmacy, The University of Texas M.D. Anderson Cancer Center, Houston, Texas
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Zhang L, Zhang Q, Yang Y, Wu C. The RNA recognition motif domains of RBM5 are required for RNA binding and cancer cell proliferation inhibition. Biochem Biophys Res Commun 2014; 444:445-50. [PMID: 24486491 DOI: 10.1016/j.bbrc.2014.01.102] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 01/21/2014] [Indexed: 01/08/2023]
Abstract
RBM5 is a known putative tumor suppressor gene that has been shown to function in cell growth inhibition by modulating apoptosis. RBM5 also plays a critical role in alternative splicing as an RNA binding protein. However, it is still unclear which domains of RBM5 are required for RNA binding and related functional activities. We hypothesized the two putative RNA recognition motif (RRM) domains of RBM5 spanning from amino acids 98-178 and 231-315 are essential for RBM5-mediated cell growth inhibition, apoptosis regulation, and RNA binding. To investigate this hypothesis, we evaluated the activities of the wide-type and mutant RBM5 gene transfer in low-RBM5 expressing A549 cells. We found that, unlike wild-type RBM5 (RBM5-wt), a RBM5 mutant lacking the two RRM domains (RBM5-ΔRRM), is unable to bind RNA, has compromised caspase-2 alternative splicing activity, lacks cell proliferation inhibition and apoptosis induction function in A549 cells. These data provide direct evidence that the two RRM domains of RBM5 are required for RNA binding and the RNA binding activity of RBM5 contributes to its function on apoptosis induction and cell growth inhibition.
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Affiliation(s)
- Lei Zhang
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China
| | - Qing Zhang
- Jiangsu Key Laboratory of Biological Cancer Therapy, Xuzhou Medical College, Xuzhou 221002, PR China
| | - Yu Yang
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China
| | - Chuanfang Wu
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China.
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Bechara EG, Sebestyén E, Bernardis I, Eyras E, Valcárcel J. RBM5, 6, and 10 differentially regulate NUMB alternative splicing to control cancer cell proliferation. Mol Cell 2013; 52:720-33. [PMID: 24332178 DOI: 10.1016/j.molcel.2013.11.010] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 09/18/2013] [Accepted: 10/22/2013] [Indexed: 12/25/2022]
Abstract
RBM5, a regulator of alternative splicing of apoptotic genes, and its highly homologous RBM6 and RBM10 are RNA-binding proteins frequently deleted or mutated in lung cancer. We report that RBM5/6 and RBM10 antagonistically regulate the proliferative capacity of cancer cells and display distinct positional effects in alternative splicing regulation. We identify the Notch pathway regulator NUMB as a key target of these factors in the control of cell proliferation. NUMB alternative splicing, which is frequently altered in lung cancer, can regulate colony and xenograft tumor formation, and its modulation recapitulates or antagonizes the effects of RBM5, 6, and 10 in cell colony formation. RBM10 mutations identified in lung cancer cells disrupt NUMB splicing regulation to promote cell growth. Our results reveal a key genetic circuit in the control of cancer cell proliferation.
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Affiliation(s)
- Elias G Bechara
- Centre de Regulació Genòmica, Dr. Aiguader, 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Endre Sebestyén
- Universitat Pompeu Fabra, Dr. Aiguader, 88, 08003 Barcelona, Spain
| | | | - Eduardo Eyras
- Universitat Pompeu Fabra, Dr. Aiguader, 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Dr. Aiguader, 88, 08003 Barcelona, Spain
| | - Juan Valcárcel
- Centre de Regulació Genòmica, Dr. Aiguader, 88, 08003 Barcelona, Spain; Universitat Pompeu Fabra, Dr. Aiguader, 88, 08003 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Dr. Aiguader, 88, 08003 Barcelona, Spain.
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Xiao SJ, Wang LY, Kimura M, Kojima H, Kunimoto H, Nishiumi F, Yamamoto N, Nishio K, Fujimoto S, Kato T, Kitagawa S, Yamane H, Nakajima K, Inoue A. S1-1/RBM10: multiplicity and cooperativity of nuclear localisation domains. Biol Cell 2013; 105:162-74. [PMID: 23294349 DOI: 10.1111/boc.201200068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Accepted: 01/03/2013] [Indexed: 12/23/2022]
Abstract
BACKGROUND INFORMATION S1-1, also called RBM10, is an RNA-binding protein of 852 residues. An alteration of its activity causes TARP syndrome, a severe X-linked disorder with pre- or post-natal lethality in affected males. Its molecular function, although still largely unknown, has been suggested to be transcription and alternative splicing. In fact, S1-1 localises in the nucleus in tissue cells and cultured cells. RESULTS By deletion and substitution mutagenesis, a classical 17-amino-acid (aa) nuclear localisation sequence (NLS1) was identified at aa 743-759 in the C-terminal region of S1-1. NLS1 was bipartite, with its N-terminal basic cluster weakly contributing to the NLS activity. S1-1 contained two additional NLSs. One was in the aa 60-136 RNA recognition motif region (NLS2), and the other was a novel NLS motif sequence in the aa 481-540 octamer-repeat (OCRE) region (NLS3). The OCRE is a domain known to be critical in splicing regulation, as shown with RBM5, a close homologue of RBM10 [Bonnal et al. (2008) Mol. Cell 32, 81-95]. The NLS activities were verified by expressing each DNA sequence linked to EGFP or a FLAG tag. These multiple NLSs acted cooperatively, and S1-1 became completely cytoplasmic after the concomitant removal of all NLS domains. In some cell types, however, S1-1 was partly cytoplasmic, suggesting that cellular localisation of S1-1 is subjected to regulation. CONCLUSIONS The present results indicate that S1-1 contains multiple NLSs that act cooperatively. Among them, the OCRE is a hitherto unreported NLS. The nuclear localisation of S1-1 appears to be regulated under certain circumstances. We discuss these NLSs in relation to the biochemical processes they are involved in.
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Affiliation(s)
- Sheng-Jun Xiao
- Department of Immunology, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan
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Peng J, Valeshabad AK, Li Q, Wang Y. Differential expression of RBM5 and KRAS in pancreatic ductal adenocarcinoma and their association with clinicopathological features. Oncol Lett 2012; 5:1000-1004. [PMID: 23425895 PMCID: PMC3576315 DOI: 10.3892/ol.2012.1080] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 12/11/2012] [Indexed: 12/13/2022] Open
Abstract
RNA binding motif 5 (RBM5) is a tumor suppressor gene that regulates cell proliferation, differentiation and apoptosis through pre-mRNA splicing of related genes. This study aimed to detect RBM5 and KRAS expression in pancreatic ductal adenocarcinoma and their association with clinicopathological features. Detection of RBM5 and KRAS expression by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting was performed at mRNA and protein levels, respectively, in pancreatic cancer and non-tumor tissues. In addition, the association of RBM5 and KRAS expression with clinicopathological parameters and tumor recurrence was analyzed. The expression of RBM5 was significantly downregulated in pancreatic cancer tissues compared to peritumoral tissues at the mRNA and protein levels. Contrastingly, KRAS was significantly overexpressed in pancreatic cancerous tissues compared to peritumoral tissues. Analysis revealed that RBM5 expression was negatively correlated with KRAS expression in pancreatic cancer. Furthermore, reduced RBM5 expression has a close association with lymph node metastasis, distant metastasis, Union for International Cancer Control (UICC) stage and nerve and venous invasion, while overexpression of KRAS proteins was significantly correlated with tumor size, lymph node metastasis, UICC stage and nerve and venous invasion of pancreatic cancer. Significant RBM5 underexpression and KRAS overexpression were observed in pancreatic cancer compared to non-tumor tissues. There is a close association of differential RBM5 and KRAS with poor clinicopathological features, suggesting their potential roles in the progression and metastasis of pancreatic cancer.
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Affiliation(s)
- Jie Peng
- Department of Gastroenterology, Xiangya Hospital, Central South University, Changsha 410008, Hunan, P.R. China
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36
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Jin W, Niu Z, Xu D, Li X. RBM5 promotes exon 4 skipping of AID
pre-mRNA by competing with the binding of U2AF65 to the polypyrimidine tract. FEBS Lett 2012; 586:3852-7. [DOI: 10.1016/j.febslet.2012.09.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 08/13/2012] [Accepted: 09/12/2012] [Indexed: 10/27/2022]
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Song Z, Wu P, Ji P, Zhang J, Gong Q, Wu J, Shi Y. Solution Structure of the Second RRM Domain of RBM5 and Its Unusual Binding Characters for Different RNA Targets. Biochemistry 2012; 51:6667-78. [DOI: 10.1021/bi300539t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhenwei Song
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Peiwen Wu
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Peng Ji
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Jihui Wu
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
| | - Yunyu Shi
- Hefei National Laboratory for Physical Sciences at
Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, People’s
Republic of China
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Li P, Wang K, Zhang J, Zhao L, Liang H, Shao C, Sutherland LC. The 3p21.3 tumor suppressor RBM5 resensitizes cisplatin-resistant human non-small cell lung cancer cells to cisplatin. Cancer Epidemiol 2012; 36:481-9. [PMID: 22609235 DOI: 10.1016/j.canep.2012.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 04/06/2012] [Accepted: 04/18/2012] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Increasing RBM5 levels inhibit tumor cell growth and promote apoptosis. In this study, we investigated the role of RBM5 in the cisplatin resistance observed in human lung non-small cell lung cancer cells and evaluated the effect of RBM5 modulation on cell growth inhibition and apoptosis induced by cisplatin in the parental non-small cell lung cancer cells A549 and their cisplatin resistant counterparts, A549/DDP cells. METHODS RBM5 mRNA and protein expression in the A549 and A549/DDP cells was analyzed by semi-quantitative RT-PCR and western blot. The A549/DDP cells were then transfected with a pcDNA3-RBM5 plasmid, and an RBM5-specific siRNA was transfected into A549 cells, prior to treatment with cisplatin. Semi-quantitative RT-PCR and western blot analyses were performed to confirm the expression of RBM5 mRNA or protein, and knockdown of RBM5 mRNA or protein, respectively. MTT assays were used to evaluate chemosensitivity to cisplatin. Apoptosis was assessed by DAPI nuclear staining and flow cytometric analysis with an Annexin-V-FITC apoptosis kit. Cytosolic cytochrome c, cleaved caspase-3 and cleaved caspase-9 were detected by western blot. RESULTS The expression of RBM5 mRNA and protein was significantly reduced in the A549/DDP cells compared with the A549 cells. Exogenous expression of RBM5 by the pcDNA3-RBM5 resensitized the response of A549/DDP to cisplatin, resulting in a significant increase in tumor-suppressing activity induced by cisplatin. In contrast, downregulation of RBM5 with siRNA in the A549 cells inhibited cisplatin-induced apoptosis. We also found that the RBM5-enhanced chemosensitivity was associated with the release of cytochrome c into the cytosol, activation of caspase-9 and the downstream marker caspase-3. CONCLUSION Our results demonstrate that RBM5 may serve as a biomarker with the ability to predict a response to cisplatin. It may also act as a prognostic indicator in lung cancer patients. Our findings suggest that there may be clinical utility for ectopic RBM5 such as enhancing and resensitizing nonresponders to cisplatin.
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Affiliation(s)
- Ping Li
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China.
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Liang H, Zhang J, Shao C, Zhao L, Xu W, Sutherland LC, Wang K. Differential expression of RBM5, EGFR and KRAS mRNA and protein in non-small cell lung cancer tissues. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2012; 31:36. [PMID: 22537942 PMCID: PMC3403968 DOI: 10.1186/1756-9966-31-36] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 04/26/2012] [Indexed: 01/22/2023]
Abstract
Background RNA binding motif 5 (RBM5) is a tumor suppressor gene that modulates apoptosis through the regulation of alternative splicing of apoptosis-related genes. This study aimed to detect RBM5 expression in non-small cell lung cancer (NSCLC) and to associate RBM5 expression with clinicopathological data from NSCLC patients and EGFR and KRAS expression to better understand the potential role of RBM5 in NSCLC. Method Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting were performed to detect expression of mRNA and protein, respectively, of RBM5, EGFR and KRAS in 120 paired non-tumor and tumor samples of NSCLC. Results The data showed that expression of RBM5 mRNA and protein was significantly reduced in NSCLC compared to normal tissues, whereas expression of both EGFR and KRAS genes was increased in NSCLC compared to normal tissues. Furthermore, the reduced RBM5 protein expression correlated with smoking status, tumor stage and lymph node metastasis of NSCLC, while overexpression of EGFR and KRAS proteins correlated with tumor stage and lymph node metastasis of NSCLC. Overexpression of KRAS protein was more frequent in smokers with NSCLC. In addition, expression of RBM5 mRNA and protein was negatively correlated with expression of EGFR and KRAS mRNA and protein in NSCLC tissues. Conclusion This study suggests further evaluation of RBM5 expression is warranted for use of RBM5 as a biomarker for NSCLC patients.
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Affiliation(s)
- Hong Liang
- Department of Respiratory Medicine, Second Affiliated Hospital of Jilin University, Changchun, Jilin 130041, China
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S1-1 nuclear domains: characterization and dynamics as a function of transcriptional activity. Biol Cell 2012; 100:523-35. [DOI: 10.1042/bc20070142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Farina B, Fattorusso R, Pellecchia M. Targeting zinc finger domains with small molecules: solution structure and binding studies of the RanBP2-type zinc finger of RBM5. Chembiochem 2011; 12:2837-45. [PMID: 22162216 PMCID: PMC3408030 DOI: 10.1002/cbic.201100582] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Indexed: 12/11/2022]
Abstract
The RNA binding motif protein 5 (RBM5), also known as Luca15 or H37, is a component of prespliceosomal complexes that regulates the alternative splicing of several mRNAs, such as Fas and caspase-2. The RBM5 gene is located at the 2p21.3 chromosomal region, which is strongly associated with lung cancer and many other cancers. Both increased and decreased levels of RBM5 can play a role in tumor progression. In particular, downregulation of rbm5 is involved in lung cancer and other cancers upon Ras activation, and, also, represents a molecular signature associated with metastasis in various solid tumors. On the other hand, upregulation of RBM5 occurs in breast and ovarian cancer. Moreover, RBM5 was also found to be involved in the early stage of the HIV-1 viral cycle, representing a potential target for the treatment of the HIV-1 infection. While the molecular basis for RNA recognition and ubiquitin interaction has been structurally characterized, small molecules binding this zinc finger (ZF) domain that might contribute to characterizing their activity and to the development of potential therapeutic agents have not yet been reported. Using an NMR screening of a fragment library we identified several binders and the complex of the most promising one, compound 1, with the RBM5 ZF1 was structurally characterized in solution. Interestingly, the binding mechanism reveals that 1 occupies the RNA binding pocket and is therefore able to compete with the RNA to bind RBM5 RanBP2-type ZF domain, as indicated by NMR studies.
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Affiliation(s)
- Biancamaria Farina
- Dr, B, Farina, Prof, M, Pellecchia Infectious Diseases and Cancer Center Sanford-Burnham Medical Research Institute 10901 North Torrey Pines Rd., La Jolla, CA Fax: (858-795-5225)
| | - Roberto Fattorusso
- Prof, R, Fattorusso Dipartimento di Scienze Ambientali Seconda Università di Napoli Via Vivaldi 43, 81100, Caserta, Italy
| | - Maurizio Pellecchia
- Dr, B, Farina, Prof, M, Pellecchia Infectious Diseases and Cancer Center Sanford-Burnham Medical Research Institute 10901 North Torrey Pines Rd., La Jolla, CA Fax: (858-795-5225)
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David CJ, Manley JL. Alternative pre-mRNA splicing regulation in cancer: pathways and programs unhinged. Genes Dev 2011; 24:2343-64. [PMID: 21041405 DOI: 10.1101/gad.1973010] [Citation(s) in RCA: 621] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alternative splicing of mRNA precursors is a nearly ubiquitous and extremely flexible point of gene control in humans. It provides cells with the opportunity to create protein isoforms of differing, even opposing, functions from a single gene. Cancer cells often take advantage of this flexibility to produce proteins that promote growth and survival. Many of the isoforms produced in this manner are developmentally regulated and are preferentially re-expressed in tumors. Emerging insights into this process indicate that pathways that are frequently deregulated in cancer often play important roles in promoting aberrant splicing, which in turn contributes to all aspects of tumor biology.
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Affiliation(s)
- Charles J David
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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Identification and characterisation of a novel antisense non-coding RNA from the RBM5 gene locus. Gene 2009; 445:7-16. [PMID: 19559772 DOI: 10.1016/j.gene.2009.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 05/16/2009] [Accepted: 06/16/2009] [Indexed: 11/20/2022]
Abstract
Previous work from our lab identified a 326 base-pair (bp) cDNA, termed Je2, which mapped to the antisense strand of intron 6 of the putative tumour suppressor gene RBM5/LUCA-15/H37, and functioned as an apoptosis suppressor. The purpose of the work described herein was to determine if Je2 is part of a larger transcript, to clone that transcript and to examine its ability to modulate RBM5 expression. Northern blot analyses in conjunction with strand-specific reverse transcription and PCR revealed two novel transcripts, one antisense and one sense, that included Je2 as well as RBM5 intron 4 sequence. Using rapid amplification of cDNA ends (RACE), a novel 1.4 kb product including Je2 and intron 4 was cloned. In vitro transcription/translation did not result in the production of any protein product, from either strand. Genomic DNA analysis revealed the presence of a putative promoter region 5' to Je2, suggesting that the cloned 1.4 kb RACE product represents an antisense transcript that initiates within intron 6 and terminates within intron 4 of the RBM5 gene. This novel antisense, non-coding RNA was termed LUST, for LUCA-15-specific transcript. Ectopic overexpression of LUST coincided with elevated expression of the full-length RBM5+5+6 alternative RBM5 RNA splice variant, and reduced expression of the truncated, cytotoxic RBM5+5+6t/Clone 26 alternative RBM5 RNA splice variant. A model is proposed whereby LUST functions co-transcriptionally to mask a sense-strand regulatory sequence, common to both RBM5+5+6 and RBM5+5+6t/Clone 26 transcripts, that when unmasked results in premature termination of RBM5+5+6, thereby generating the cytotoxic truncated product, RBM5+5+6t/Clone 26. These results suggest that LUST is a novel, functional, non-coding RNA that plays a role in determining the apoptotic fate of a cell by regulating the expression of RBM5 splice variants.
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Up-regulation of the proapoptotic caspase 2 splicing isoform by a candidate tumor suppressor, RBM5. Proc Natl Acad Sci U S A 2008; 105:15708-13. [PMID: 18840686 DOI: 10.1073/pnas.0805569105] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Similar to many genes involved in programmed cell death (PCD), the caspase 2 (casp-2) gene generates both proapoptotic and antiapoptotic isoforms by alternative splicing. Using a yeast RNA-protein interaction assay, we identified RBM5 (also known as LUCA-15) as a protein that binds to casp-2 pre-mRNA. In both transfected cells and in vitro splicing assay, RBM5 enhances the formation of proapoptotic Casp-2L. RBM5 binds to a U/C-rich sequence immediately upstream of the previously identified In100 splicing repressor element. Our mutagenesis experiments demonstrate that RBM5 binding to this intronic sequence regulates the ratio of proapoptotic/antiapoptotic casp-2 splicing isoforms, suggesting that casp-2 splicing regulation by RBM5 may contribute to its tumor suppressor activity. Our work has uncovered a player in casp-2 alternative splicing regulation and revealed a link between the alternative splicing regulator and the candidate tumor suppressor gene. Together with previous studies, our work suggests that splicing control of cell death genes may be an important aspect in tumorigenesis. Enhancing the expression or activities of splicing regulators that promote the production of proapoptotic splicing isoforms might provide a therapeutic approach to cancer.
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Bonnal S, Martínez C, Förch P, Bachi A, Wilm M, Valcárcel J. RBM5/Luca-15/H37 Regulates Fas Alternative Splice Site Pairing after Exon Definition. Mol Cell 2008; 32:81-95. [DOI: 10.1016/j.molcel.2008.08.008] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 05/14/2008] [Accepted: 08/05/2008] [Indexed: 10/21/2022]
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Wang K, Ubriaco G, Sutherland LC. RBM6-RBM5 transcription-induced chimeras are differentially expressed in tumours. BMC Genomics 2007; 8:348. [PMID: 17908320 PMCID: PMC2174484 DOI: 10.1186/1471-2164-8-348] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Accepted: 10/01/2007] [Indexed: 11/29/2022] Open
Abstract
Background Transcription-induced chimerism, a mechanism involving the transcription and intergenic splicing of two consecutive genes, has recently been estimated to account for ~5% of the human transcriptome. Despite this prevalence, the regulation and function of these fused transcripts remains largely uncharacterised. Results We identified three novel transcription-induced chimeras resulting from the intergenic splicing of a single RNA transcript incorporating the two neighbouring 3p21.3 tumour suppressor locus genes, RBM6 and RBM5, which encode the RNA Binding Motif protein 6 and RNA Binding Motif protein 5, respectively. Each of the three novel chimeric transcripts lacked exons 3, 6, 20 and 21 of RBM6 and exon 1 of RBM5. Differences between the transcripts were associated with the presence or absence of exon 4, exon 5 and a 17 nucleotide (nt) sequence from intron 10 of RBM6. All three chimeric transcripts incorporated the canonical splice sites from both genes (excluding the 17 nt intron 10 insertion). Differential expression was observed in tumour tissue compared to non-tumour tissue, and amongst tumour types. In breast tumour tissue, chimeric expression was associated with elevated levels of RBM6 and RBM5 mRNA, and increased tumour size. No protein expression was detected by in vitro transcription/translation. Conclusion These results suggest that RBM6 mRNA experiences altered co-transcriptional gene regulation in certain cancers. The results also suggest that RBM6-RBM5 transcription-induced chimerism might be a process that is linked to the tumour-associated increased transcriptional activity of the RBM6 gene. It appears that none of the transcription-induced chimeras generates a protein product; however, the novel alternative splicing, which affects putative functional domains within exons 3, 6 and 11 of RBM6, does suggest that the generation of these chimeric transcripts has functional relevance. Finally, the association of chimeric expression with breast tumour size suggests that RBM6-RBM5 chimeric expression may be a potential tumour differentiation marker.
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Affiliation(s)
- Ke Wang
- Tumour Biology Group, Regional Cancer Program of the Sudbury Regional Hospital, Sudbury, Ontario, Canada
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, Jilin, China
| | - Gino Ubriaco
- Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| | - Leslie C Sutherland
- Tumour Biology Group, Regional Cancer Program of the Sudbury Regional Hospital, Sudbury, Ontario, Canada
- Northern Ontario School of Medicine, Sudbury, Ontario, Canada
- Biomolecular Sciences Program, Laurentian University, Sudbury, Ontario, Canada
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