1
|
Manet E, Polvèche H, Mure F, Mrozek-Gorska P, Roisné-Hamelin F, Hammerschmidt W, Auboeuf D, Gruffat H. Modulation of alternative splicing during early infection of human primary B lymphocytes with Epstein-Barr virus (EBV): a novel function for the viral EBNA-LP protein. Nucleic Acids Res 2021; 49:10657-10676. [PMID: 34530456 PMCID: PMC8501971 DOI: 10.1093/nar/gkab787] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 08/27/2021] [Accepted: 09/01/2021] [Indexed: 12/29/2022] Open
Abstract
Epstein-Barr virus (EBV) is a human herpesvirus associated with human cancers worldwide. Ex vivo, the virus efficiently infects resting human B lymphocytes and induces their continuous proliferation. This process is accompanied by a global reprogramming of cellular gene transcription. However, very little is known on the impact of EBV infection on the regulation of alternative splicing, a pivotal mechanism that plays an essential role in cell fate determination and is often deregulated in cancer. In this study, we have developed a systematic time-resolved analysis of cellular mRNA splice variant expression during EBV infection of resting B lymphocytes. Our results reveal that major modifications of alternative splice variant expression appear as early as day 1 post-infection and suggest that splicing regulation provides—besides transcription—an additional mechanism of gene expression regulation at the onset of B cell activation and proliferation. We also report a role for the viral proteins, EBNA2 and EBNA-LP, in the modulation of specific alternative splicing events and reveal a previously unknown function for EBNA-LP—together with the RBM4 splicing factor—in the alternative splicing regulation of two important modulators of cell proliferation and apoptosis respectively, NUMB and BCL-X.
Collapse
Affiliation(s)
- Evelyne Manet
- CIRI, Centre International de Recherche en Infectiologie, RNA Expression in Viruses and Eukaryotes Group, Univ Lyon, Université Claude Bernard Lyon I, INSERM U1111, CNRS UMR5308, ENS Lyon, Lyon F-69007, France
| | | | - Fabrice Mure
- CIRI, Centre International de Recherche en Infectiologie, RNA Expression in Viruses and Eukaryotes Group, Univ Lyon, Université Claude Bernard Lyon I, INSERM U1111, CNRS UMR5308, ENS Lyon, Lyon F-69007, France
| | - Paulina Mrozek-Gorska
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research, D-81377 Munich, Germany
| | - Florian Roisné-Hamelin
- CIRI, Centre International de Recherche en Infectiologie, RNA Expression in Viruses and Eukaryotes Group, Univ Lyon, Université Claude Bernard Lyon I, INSERM U1111, CNRS UMR5308, ENS Lyon, Lyon F-69007, France
| | - Wolfgang Hammerschmidt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research, D-81377 Munich, Germany
| | | | - Henri Gruffat
- CIRI, Centre International de Recherche en Infectiologie, RNA Expression in Viruses and Eukaryotes Group, Univ Lyon, Université Claude Bernard Lyon I, INSERM U1111, CNRS UMR5308, ENS Lyon, Lyon F-69007, France
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Sun Y, Bao Y, Han W, Song F, Shen X, Zhao J, Zuo J, Saffen D, Chen W, Wang Z, You X, Wang Y. Autoregulation of RBM10 and cross-regulation of RBM10/RBM5 via alternative splicing-coupled nonsense-mediated decay. Nucleic Acids Res 2017; 45:8524-8540. [PMID: 28586478 PMCID: PMC5737846 DOI: 10.1093/nar/gkx508] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 05/27/2017] [Indexed: 12/15/2022] Open
Abstract
Mutations in the spliceosomal RNA binding protein RBM10 cause TARP syndrome and are frequently observed in lung adenocarcinoma (LUAD). We have previously shown that RBM10 enhances exon skipping of its target genes, including its paralog RBM5. Here, we report that RBM10 negatively regulates its own mRNA and protein expression and that of RBM5 by promoting alternative splicing-coupled nonsense-mediated mRNA decay (AS-NMD). Through computational analysis and experimental validation, we identified RBM10-promoted skipping of exon 6 or 12 in RBM10 and exon 6 or 16 in RBM5 as the underlying AS-NMD events. Importantly, we showed that LUAD-associated mutations affecting splice sites of RBM10 exons 6 or 12 abolished exon inclusion and correlated with reduced expression of RBM10 RNA. Together, our investigations have revealed novel molecular mechanisms underlying RBM10 autoregulation and cross-regulation of RBM5, thereby providing insights concerning the functions of RBM10 under various physiological and pathological conditions. Our combined computational and experimental approach should be useful for elucidating the role of AS-NMD in auto- and cross-regulation by other splicing regulators.
Collapse
Affiliation(s)
- Yue Sun
- School of Life Sciences, Fudan University, Shanghai 200438, China.,Institutes of Brain Science, Fudan University, Shanghai 200032, China.,Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Yufang Bao
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Wenjian Han
- Key Lab of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Science, Shanghai 200031, China
| | - Fan Song
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Xianfeng Shen
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Jiawei Zhao
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Ji Zuo
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - David Saffen
- Institutes of Brain Science, Fudan University, Shanghai 200032, China.,Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.,State Key Laboratory for Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Wei Chen
- Department of Biology, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zefeng Wang
- Key Lab of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Science, Shanghai 200031, China
| | - Xintian You
- Zuse Institute Berlin, Takustrasse 7, Berlin 14195, Germany
| | - Yongbo Wang
- Department of Cellular and Genetic Medicine, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Mitochondria Biogenesis and Bioenergetics Gene Profiles in Isogenic Prostate Cells with Different Malignant Phenotypes. BIOMED RESEARCH INTERNATIONAL 2016; 2016:1785201. [PMID: 27478826 PMCID: PMC4958422 DOI: 10.1155/2016/1785201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 06/06/2016] [Indexed: 12/28/2022]
Abstract
Background. The most significant hallmarks of cancer are directly or indirectly linked to deregulated mitochondria. In this study, we sought to profile mitochondria associated genes in isogenic prostate cell lines with different tumorigenic phenotypes from the same patient. Results. Two isogenic human prostate cell lines RC77N/E (nonmalignant cells) and RC77T/E (malignant cells) were profiled for expression of mitochondrial biogenesis and energy metabolism genes by qRT-PCR using the Human Mitochondria and the Mitochondrial Energy Metabolism RT2 PCR arrays. Forty-seven genes were differentially regulated between the two cell lines. The interaction and regulatory networks of these genes were generated by Ingenuity Pathway Analysis. UCP2 was the most significantly upregulated gene in primary adenocarcinoma cells in the current study. The overexpression of UCP2 upon malignant transformation was further validated using human prostatectomy clinical specimens. Conclusions. This study demonstrates the overexpression of multiple genes that are involved in mitochondria biogenesis, bioenergetics, and modulation of apoptosis. These genes may play a role in malignant transformation and disease progression. The upregulation of some of these genes in clinical samples indicates that some of the differentially transcribed genes could be the potential targets for therapeutic interventions.
Collapse
|
7
|
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.
Collapse
|
8
|
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.
Collapse
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.
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Zhang J, Cui Z, Feng G, Bao G, Xu G, Sun Y, Wang L, Chen J, Jin H, Liu J, Yang L, Li W. RBM5 and p53 expression after rat spinal cord injury: implications for neuronal apoptosis. Int J Biochem Cell Biol 2015; 60:43-52. [PMID: 25578565 DOI: 10.1016/j.biocel.2014.12.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Revised: 12/02/2014] [Accepted: 12/28/2014] [Indexed: 12/14/2022]
Abstract
RBM5 (RNA-binding motif protein 5), a nuclear RNA binding protein, is known to trigger apoptosis and induce cell cycle arrest by regulating the activity of the tumor suppressor protein p53. However, its expression and function in spinal cord injury (SCI) are still unknown. To investigate whether RBM5 is involved in central nervous system injury and repair, we performed an acute SCI model in adult rats in this study. Our results showed RBM5 was unregulated significantly after SCI, which was accompanied with an increase in the levels of apoptotic proteins such as p53, Bax, and active caspase-3. Immunofluorescent labeling also showed that traumatic SCI induced RBM5 location changes and co-localization with active caspase-3 in neurons. To further probe the role of RBM5, a neuronal cell line PC12 was employed to establish an apoptotic model. Knockdown of RBM5 apparently decreased the level of p53 as well as active caspase-3, demonstrating its pro-apoptotic role in neurons by regulating expressions of p53 and caspase-3. Taken together, our findings indicate that RBM5 promotes neuronal apoptosis through modulating p53 signaling pathway following SCI.
Collapse
Affiliation(s)
- Jinlong Zhang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Zhiming Cui
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China.
| | - Guijuan Feng
- Department of Stomatology, Affiliated Hospital of Nantong University, Nantong, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Guofeng Bao
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Guanhua Xu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Yuyu Sun
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Lingling Wang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Jiajia Chen
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Huricha Jin
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Jian Liu
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Longfei Yang
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| | - Weidong Li
- Department of Spine Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, 226001 Nantong, Jiangsu, People's Republic of China
| |
Collapse
|
11
|
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: 246] [Impact Index Per Article: 22.4] [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.
Collapse
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.
| |
Collapse
|
12
|
O'Bryan MK, Clark BJ, McLaughlin EA, D'Sylva RJ, O'Donnell L, Wilce JA, Sutherland J, O'Connor AE, Whittle B, Goodnow CC, Ormandy CJ, Jamsai D. RBM5 is a male germ cell splicing factor and is required for spermatid differentiation and male fertility. PLoS Genet 2013; 9:e1003628. [PMID: 23935508 PMCID: PMC3723494 DOI: 10.1371/journal.pgen.1003628] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 05/30/2013] [Indexed: 12/30/2022] Open
Abstract
Alternative splicing of precursor messenger RNA (pre-mRNA) is common in mammalian cells and enables the production of multiple gene products from a single gene, thus increasing transcriptome and proteome diversity. Disturbance of splicing regulation is associated with many human diseases; however, key splicing factors that control tissue-specific alternative splicing remain largely undefined. In an unbiased genetic screen for essential male fertility genes in the mouse, we identified the RNA binding protein RBM5 (RNA binding motif 5) as an essential regulator of haploid male germ cell pre-mRNA splicing and fertility. Mice carrying a missense mutation (R263P) in the second RNA recognition motif (RRM) of RBM5 exhibited spermatid differentiation arrest, germ cell sloughing and apoptosis, which ultimately led to azoospermia (no sperm in the ejaculate) and male sterility. Molecular modelling suggested that the R263P mutation resulted in compromised mRNA binding. Within the adult mouse testis, RBM5 localises to somatic and germ cells including spermatogonia, spermatocytes and round spermatids. Through the use of RNA pull down coupled with microarrays, we identified 11 round spermatid-expressed mRNAs as putative RBM5 targets. Importantly, the R263P mutation affected pre-mRNA splicing and resulted in a shift in the isoform ratios, or the production of novel spliced transcripts, of most targets. Microarray analysis of isolated round spermatids suggests that altered splicing of RBM5 target pre-mRNAs affected expression of genes in several pathways, including those implicated in germ cell adhesion, spermatid head shaping, and acrosome and tail formation. In summary, our findings reveal a critical role for RBM5 as a pre-mRNA splicing regulator in round spermatids and male fertility. Our findings also suggest that the second RRM of RBM5 is pivotal for appropriate pre-mRNA splicing. The production of functional spermatozoa is an extraordinarily complex process that transforms a conventional round cell into the highly specialised sperm cell. These events require the coordinated activation of thousands of genes. It is likely that this complexity contributes to the large number of idiopathic infertility cases seen in humans. In an effort to improve the field's understanding of male fertility, we used a random mutagenesis screen to produce the Joey mouse line and to conclusively define RBM5 as an essential regulator of male fertility. The Joey line carries a mutation in the Rbm5 gene, which leads to a complete block of spermatid (haploid male germ cell) differentiation and ultimately a total loss of sperm production. Our results reveal a physiological role for RBM5 in the splicing of several spermatid-expressed mRNAs that are critical for the production of spermatozoa. This study is the first to show that RBM5, via its effects on mRNA splicing in the testis, is required for male fertility. These data improve our understanding of the regulatory networks of gene expression that control sperm production and as such may lead to the development of novel approaches to enhance or suppress fertility in men.
Collapse
Affiliation(s)
- Moira K. O'Bryan
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
- The ARC Centre of Excellence in Biotechnology & Development, Monash University, Melbourne, Australia
| | - Brett J. Clark
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
| | - Eileen A. McLaughlin
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
- Priority Research Centre in Chemical Biology, The University of Newcastle, Callaghan, Australia
| | - Rebecca J. D'Sylva
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
| | - Liza O'Donnell
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
- Prince Henry's Institute, Melbourne, Australia
| | - Jacqueline A. Wilce
- Department of Biochemistry & Molecular Biology, Monash University, Melbourne, Australia
| | - Jessie Sutherland
- Priority Research Centre in Chemical Biology, The University of Newcastle, Callaghan, Australia
| | - Anne E. O'Connor
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
- The ARC Centre of Excellence in Biotechnology & Development, Monash University, Melbourne, Australia
| | - Belinda Whittle
- Australian Phenomics Facility, The Australian National University, Canberra, Australia
| | | | | | - Duangporn Jamsai
- Department of Anatomy & Developmental Biology, Monash University, Melbourne, Australia
- The ARC Centre of Excellence in Biotechnology & Development, Monash University, Melbourne, Australia
- * E-mail:
| |
Collapse
|
13
|
Shao C, Yang B, Zhao L, Wang S, Zhang J, Wang K. Tumor suppressor gene RBM5 delivered by attenuated Salmonella inhibits lung adenocarcinoma through diverse apoptotic signaling pathways. World J Surg Oncol 2013; 11:123. [PMID: 23721095 PMCID: PMC3673837 DOI: 10.1186/1477-7819-11-123] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 05/16/2013] [Indexed: 12/31/2022] Open
Abstract
Background RBM5 (RNA-binding motif protein 5, also named H37/LUCA-15) gene from chromosome 3p21.3 has been demonstrated to be a tumor suppressor. Current researches in vitro confirm that RBM5 can suppress the growth of lung adenocarcinoma cells by inducing apoptosis. There is still no effective model in vivo, however, that thoroughly investigates the effect and molecular mechanism of RBM5 on lung adenocarcinoma. Method We established the transplanted tumor model on BALB/c nude mice using the A549 cell line. The mice were treated with the recombinant plasmids carried by attenuated Salmonella to induce the overexpression of RBM5 in tumor tissues. RBM5 overexpression was confirmed by immunohistochemistry staining. H&E staining was performed to observe the histological performance on plasmids-treated A549 xenografts. Apoptosis was assessed by TUNEL staining with a TUNEL detection kit. Apoptosis-regulated genes were detected by Western blot. Results We successful established the lung adenocarcinoma animal model in vivo. The growth of tumor xenografts was significantly retarded on the mice treated with pcDNA3.1-RBM5 carried by attenuated Salmonella compared to that on mice treated with pcDNA3.1. Overexpression of RBM5 enhanced the apoptosis in tumor xenografts. Furthermore, the expression of Bcl-2 protein was decreased significantly, while the expression of BAX, TNF-α, cleaved caspase-3, cleaved caspase-8, cleaved caspase-9 and cleaved PARP proteins was significantly increased in the pcDNA3.1-RBM5-treated mice as compared to that in the control mice. Conclusions In this study, we established a novel animal model to determine RBM5 function in vivo, and concluded that RBM5 inhibited tumor growth in mice by inducing apoptosis. The study suggests that although RBM5’s involvement in the death receptor-mediated apoptotic pathway is still to be investigated, RBM5-mediated growth suppression, at least in part, employs regulation of the mitochondrial apoptotic pathways.
Collapse
Affiliation(s)
- Chen Shao
- Department of Respiratory Medicine, Second Affiliated Hospital of Jilin University, 18 Ziqiang Street, Changchun, Jilin 130041, China
| | | | | | | | | | | |
Collapse
|
14
|
Zhao L, Li R, Shao C, Li P, Liu J, Wang K. 3p21.3 tumor suppressor gene RBM5 inhibits growth of human prostate cancer PC-3 cells through apoptosis. World J Surg Oncol 2012; 10:247. [PMID: 23158838 PMCID: PMC3544648 DOI: 10.1186/1477-7819-10-247] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 10/24/2012] [Indexed: 01/12/2023] Open
Abstract
Background Recent studies have indicated that the nuclear RNA-binding protein RBM5 has the ability to modulate apoptosis and suppress tumor growth. The aim of this study is to investigate the expression of RBM5 in human prostate cancer and its mechanism of tumor suppression. Methods The expression of RBM5 protein in cancerous prostatic tissues and normal tissues was examined by IHC. PC-3 cell line was used to determine the apoptotic function of RBM5 in vitro. PC-3 cells were transiently transfected with pcDNA3.1-RBM5. Cell viability was determined by MTT assay. Rhodamine 123 staining and Annexin V analysis were performed to observe the apoptotic activity of PC-3 cells overexpressing RBM5. Expression of apoptosis-related genes was assessed by western blot. Results The expression of RBM5 protein was significantly decreased in cancerous prostatic tissues compared to the normal tissues. PC-3 cells overexpressing RBM5 showed not only significant growth inhibition compared with the vector controls, but also dysfunction of mitochondrial membrane potential and increased apoptotic activity. To further define RBM5 function in apoptotic pathways, we investigated differential expression profiles of various BH3-only proteins including Bid, Bad, and Bim, and apoptosis regulatory proteins include P53, cleaved caspase9, and cleaved caspase3. We found that the expression of both BH3-only proteins and apoptosis regulatory proteins was increased in RBM5 transfected cells. Conclusion The expression of RBM5 protein was significantly decreased in cancerous prostatic tissues, which suggests that RBM5 plays an important role in the pathogenesis of prostate cancer. RBM5 may induce the apoptosis of prostate cancer PC-3 cells by modulating the mitochondrial apoptotic pathway, and thus RBM5 might be a promising target for gene therapy on prostate cancer.
Collapse
Affiliation(s)
- Lijing Zhao
- Department of Pathophysiology, Norman Bethune College of Medicine of Jilin University, Changchun, Jilin 130021, China
| | | | | | | | | | | |
Collapse
|
15
|
Munichandrababu T, Bhaskar BV, Ravi S, Bhuvaneswar C, Rajendra W. Structure based virtual screening of non-steroidal anti-inflammatory drugs (NSAIDs) against RNA-binding motif 6 (RBM6) involved in human lung cancer. Med Chem Res 2012. [DOI: 10.1007/s00044-012-0276-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
16
|
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]
|
17
|
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.
Collapse
Affiliation(s)
- Ping Li
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, Changchun, China.
| | | | | | | | | | | | | |
Collapse
|
18
|
A critical role for non-coding RNA GAS5 in growth arrest and rapamycin inhibition in human T-lymphocytes. Biochem Soc Trans 2011; 39:482-6. [PMID: 21428924 DOI: 10.1042/bst0390482] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Non-coding RNA GAS5 (growth arrest-specific transcript 5) is a 5'-TOP (5'-terminal oligopyrimidine tract) RNA, whose translation, and consequently also stability, is controlled by the mTOR (mammalian target of rapamycin) pathway. GAS5 was identified by functional expression cloning and is necessary and sufficient for normal growth arrest in both leukaemic and untransformed human T-lymphocytes. GAS5 is also required for the inhibitory effects of rapamycin and its analogues on T-cells. The striking functional effects of GAS5 may be mediated through the snoRNAs (small nucleolar RNAs) encoded in its introns and/or through the unusual folding of the mRNA itself, which sequesters, and therefore inhibits, the glucocorticoid receptor.
Collapse
|
19
|
Oh JJ, Taschereau EO, Koegel AK, Ginther CL, Rotow JK, Isfahani KZ, Slamon DJ. RBM5/H37 tumor suppressor, located at the lung cancer hot spot 3p21.3, alters expression of genes involved in metastasis. Lung Cancer 2010; 70:253-62. [PMID: 20338664 DOI: 10.1016/j.lungcan.2010.02.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 02/17/2010] [Accepted: 02/22/2010] [Indexed: 12/11/2022]
Abstract
The RBM5/H37 gene is located at the most 'sought-after' tumor suppressor locus in lung cancer, 3p21.3. This region of most frequent chromosomal deletion found at the earliest stage in lung cancer development houses 19 genes, many of which may act together as a 'tumor suppressor group', representing one of the most promising opportunities for development of new diagnostics/prognostics and therapeutics for lung cancer as well as for many other types of cancers. For the past decade, we have demonstrated tumor suppressor function of RBM5 in vitro and in vivo involving cell cycle arrest and apoptosis, as well as loss of RBM5 mRNA and protein expression in primary lung tumors. Here we report our latest data suggesting that RBM5 may regulate inhibition of metastasis in lung cancer. We performed cDNA microarray to identify global gene expression changes caused by RBM5 gene knockdown. In order to identify "consensus" pathways consistently deregulated by RBM5 loss irrespective of genetic background, the experiments were repeated in three different lung cancer cell lines of varying RBM5 expression levels, a normal lung epithelial cell line, and a normal breast epithelial cell line. Both Gene Set Enrichment Analysis (GSEA) and individual gene analysis identified consistent, statistically significant gene expression changes common to all five cell pairs examined. Genes involved in the functions of cell adhesion, migration and motility, known to be important in the metastatic process, were upregulated with RBM5-knockdown. These genes include Rac1, β-catenin, collagen, laminin and the overall gene set of the gene ontology group "proteinaceous extracellular matrix". Among these, we have focused on Rac1 and β-catenin which play essential roles in cell movement downstream of Wnt signaling. We have confirmed increased protein expression of β-catenin and increased protein activation of Rac1 with RBM5-knockdown. In addition, we found that RBM5 protein expression loss in primary lung tumors is correlated with increased lymph node metastasis in a small number of lung cancer patients. These data are corroborated by an independent report showing RBM5 as part of a 17-gene signature of metastasis in primary solid tumors. Taken together, the accumulated evidence suggests that RBM5 expression loss may increase the metastatic potential of tumors. Further study is warranted to evaluate the potential clinical utility of RBM5 in lung cancer diagnostics, prognostics and therapeutics.
Collapse
Affiliation(s)
- Juliana J Oh
- Division of Hematology/Oncology, University of California at Los Angeles School of Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | |
Collapse
|
20
|
Kobayashi T, Ishida J, Musashi M, Ota S, Yoshida T, Shimizu Y, Chuma M, Kawakami H, Asaka M, Tanaka J, Imamura M, Kobayashi M, Itoh H, Edamatsu H, Sutherland LC, Brachmann RK. p53 transactivation is involved in the antiproliferative activity of the putative tumor suppressor RBM5. Int J Cancer 2010; 128:304-18. [PMID: 20309933 DOI: 10.1002/ijc.25345] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Accepted: 03/09/2010] [Indexed: 12/12/2022]
Abstract
RBM5 (RNA-binding motif protein 5) is a nuclear RNA binding protein containing 2 RNA recognition motifs. The RBM5 gene is located at the tumor suppressor locus 3p21.3. Deletion of this locus is the most frequent genetic alteration in lung cancer, but is also found in other human cancers. RBM5 is known to induce apoptosis and cell cycle arrest but the molecular mechanisms of RBM5 function are poorly understood. Here, we show that RBM5 is important for the activity of the tumor suppressor protein p53. Overexpression of RBM5 enhanced p53-mediated inhibition of cell growth and colony formation. Expression of RBM5 augmented p53 transcriptional activity in reporter gene assays and resulted in increased mRNA and protein levels for endogenous p53 target genes. In contrast, shRNA-mediated knockdown of endogenous RBM5 led to decreased p53 transcriptional activity and reduced levels of mRNA and protein for endogenous p53 target genes. RBM5 affected protein, but not mRNA, levels of endogenous p53 after DNA damage suggest that RBM5 contributes to p53 activity through post-transcriptional mechanisms. Our results show that RBM5 contributes to p53 transcriptional activity after DNA damage and that growth suppression and apoptosis mediated by RBM5 are linked to activity of the tumor suppressor protein p53.
Collapse
|
21
|
|
22
|
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.
Collapse
|
23
|
Abstract
In a recent issue of Molecular Cell, Bonnal et al. (2008) demonstrate that the tumor suppressor gene RBM5 regulates alternative splicing of Fas pre-mRNA by interfering with splice-site pairing.
Collapse
Affiliation(s)
- Matthew V Kotlajich
- Department of Microbiology and Molecular Genetics, University of California, Irvine, Irvine, CA 92697-4025, USA
| | | |
Collapse
|
24
|
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.
Collapse
|
25
|
GAS5, a non-protein-coding RNA, controls apoptosis and is downregulated in breast cancer. Oncogene 2008; 28:195-208. [PMID: 18836484 DOI: 10.1038/onc.2008.373] [Citation(s) in RCA: 617] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Effective control of both cell survival and cell proliferation is critical to the prevention of oncogenesis and to successful cancer therapy. Using functional expression cloning, we have identified GAS5 (growth arrest-specific transcript 5) as critical to the control of mammalian apoptosis and cell population growth. GAS5 transcripts are subject to complex post-transcriptional processing and some, but not all, GAS5 transcripts sensitize mammalian cells to apoptosis inducers. We have found that, in some cell lines, GAS5 expression induces growth arrest and apoptosis independently of other stimuli. GAS5 transcript levels were significantly reduced in breast cancer samples relative to adjacent unaffected normal breast epithelial tissues. The GAS5 gene has no significant protein-coding potential but expression encodes small nucleolar RNAs (snoRNAs) in its introns. Taken together with the recent demonstration of tumor suppressor characteristics in the related snoRNA U50, our observations suggest that such snoRNAs form a novel family of genes controlling oncogenesis and sensitivity to therapy in cancer.
Collapse
|
26
|
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]
|
27
|
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.
Collapse
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
| |
Collapse
|
28
|
Oh JJ, Koegel AK, Phan DT, Razfar A, Slamon DJ. The two single nucleotide polymorphisms in the H37/RBM5 tumour suppressor gene at 3p21.3 correlated with different subtypes of non-small cell lung cancers. Lung Cancer 2007; 58:7-14. [PMID: 17606309 PMCID: PMC2071930 DOI: 10.1016/j.lungcan.2007.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 05/15/2007] [Accepted: 05/17/2007] [Indexed: 02/08/2023]
Abstract
Allele loss and genetic alteration in chromosome 3p, particularly in 3p21.3 region, are the most frequent and the earliest genomic abnormalities found in lung cancer. Multiple 3p21.3 genes exhibit various degrees of tumour suppression activity suggesting that 3p21.3 genes may function as an integrated tumour suppressor region through their diverse biological activities. We have previously demonstrated growth inhibitory effects and tumour suppression mechanism of the H37/RBM5 gene which is one of the 19 genes residing in the 370kb minimal overlap region at 3p21.3. In the current study, in an attempt to find, if any, mutations in the H37 coding region in lung cancer cells, we compared nucleotide sequences of the entire H37 gene in tumour versus adjacent normal tissues from 17 non-small cell lung cancer (NSCLC) patients. No mutations were detected; instead, we found the two silent single nucleotide polymorphisms (SNPs), C1138T and C2185T, within the coding region of the H37 gene. In addition, we found that specific allele types at these SNP positions are correlated with different histological subtypes of NSCLC; tumours containing heterozygous alleles (C+T) at these SNP positions are more likely to be associated with adenocarcinoma (AC), whereas, homozygous alleles (either C or T) are associated with squamous cell carcinoma (SCC) (p=0.0098). We postulate that, these two silent polymorphisms may be in linkage disequilibrium (LD) with a disease causative allele in the 3p21.3 tumour suppressor region which is packed with a large number of important genes affecting lung cancer development. In addition, because of prevalent loss of heterozygosity (LOH) detected at 3p21.3 which precedes lung cancer initiation, these SNPs may be developed into a marker screening for the high risk individuals.
Collapse
MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/pathology
- Adult
- Aged
- Alleles
- Biomarkers, Tumor
- Carcinoma, Non-Small-Cell Lung/classification
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/pathology
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/pathology
- Cell Cycle Proteins/genetics
- Chromosomes, Human, Pair 3
- DNA-Binding Proteins/genetics
- Female
- Gene Expression Regulation, Neoplastic
- Genes, Tumor Suppressor
- Humans
- Loss of Heterozygosity
- Lung Neoplasms/classification
- Lung Neoplasms/genetics
- Lung Neoplasms/pathology
- Male
- Middle Aged
- Polymorphism, Single Nucleotide
- RNA-Binding Proteins/genetics
- Tumor Suppressor Proteins/genetics
Collapse
Affiliation(s)
- Juliana J Oh
- Division of Hematology/Oncology, University of California at Los Angeles School of Medicine, 11-934 Factor Building, 10833 Le Conte Avenue, Los Angeles, CA 90095, USA.
| | | | | | | | | |
Collapse
|
29
|
Shu Y, Rintala-Maki ND, Wall VE, Wang K, Goard CA, Langdon CE, Sutherland LC. The apoptosis modulator and tumour suppressor protein RBM5 is a phosphoprotein. Cell Biochem Funct 2007; 25:643-53. [PMID: 16927403 DOI: 10.1002/cbf.1366] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
RBM5/LUCA-15/H37 is a nuclear SR-related RNA binding protein with the ability to modulate both apoptosis and the cell cycle, and retard tumour formation. How RBM5 functions to carry out these, potentially interrelated, biological activities is unknown. Since reversible phosphorylation has been shown to play an important role in the regulation of SR protein function, apoptosis and cell cycle control, in an attempt to elucidate the underlying mechanisms regulating RBM5 function, the phosphorylation status of RBM5 was investigated. Whole cell lysate from growing cell cultures was treated with the broad phosphatase spectrum of CIP, resulting in a decrease in the molecular mass of RBM5. A similar decrease in molecular mass, of a subset of RBM5 proteins, was observed during growth factor deprivation, in a manner consistent with partial dephosphorylation of RBM5. Molecular mass increased upon growth factor addition, demonstrating that this apoptosis-associated alteration in molecular mass was a reversible process. Immunoprecipitation and mutagenesis experiments strongly suggested that phosphotyrosines are not present in RBM5 under normal growth conditions, and that serine 69 is phosphorylated, but not by Akt kinase. Taken together, these results suggest that reversible phosphorylation of RBM5 is a mechanism capable of regulating RBM5 participation in modulating apoptosis, and perhaps tumour suppression.
Collapse
Affiliation(s)
- Yanjun Shu
- Tumour Biology Group, Regional Cancer Program of the Hôpital régional de Sudbury Regional Hospital, Sudbury, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
30
|
Rintala-Maki ND, Goard CA, Langdon CE, Wall VE, Traulsen KEA, Morin CD, Bonin M, Sutherland LC. Expression of RBM5-related factors in primary breast tissue. J Cell Biochem 2007; 100:1440-58. [PMID: 17131366 DOI: 10.1002/jcb.21134] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The aim of this study was to examine the expression of the RBM5 tumor suppressor, in relation to RBM6 and RBM10, to obtain a better understanding of the potential role played by these RBM5-related factors in the regulation of RBM5 tumor-suppressor activity. Paired non-tumor and tumor samples were obtained from 73 breast cancer patients. RNA and protein expression were examined by semi-quantitative reverse transcription-polymerase chain reaction and immunoblot, respectively. Data were analyzed using various statistical methods to test for correlations amongst the RBM5-related factors, and between the factors and various pathological parameters. Most notably, RBM5, RBM10v1, and HER2 protein expression levels were elevated in tumor tissue (P < 0.0001). RBM5 and RBM10v1 protein expression were significantly positively correlated (P < 0.001), as were RBM5 and HER2 protein expression (P < 0.01), in both non-tumor and tumor tissue, whereas RBM10v1 and HER2 protein expression were only marginally correlated, in non-tumor tissue (P < 0.05). Interestingly, RBM5 and RBM10v1 protein expression were both deregulated in relation to RNA expression in tumor tissue. RBM10v2 and RBM6 RNA were highly significantly positively correlated in relation to various factors relating to poor prognosis (P < 0.0001). To our knowledge, this study is the first to examine RBM5 expression at both the RNA and protein level in primary breast tumor tissue, and the first to examine expression of all RBM5-related factors in a comprehensive manner. The results provide a graphic illustration that RBM5-related factors are significantly differentially expressed in breast cancer, and suggest complex inter-related regulatory networks involving alternative splicing, oncogenic expression, and tissue-specific function.
Collapse
Affiliation(s)
- Nina D Rintala-Maki
- Tumour Biology Group, Regional Cancer Program, Hôpital Régional de Sudbury Regional Hospital, Sudbury, Ontario, Canada
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Maarabouni MM, Williams GT. The antiapoptotic RBM5/LUCA-15/H37 gene and its role in apoptosis and human cancer: research update. ScientificWorldJournal 2006; 6:1705-12. [PMID: 17195868 PMCID: PMC1825760 DOI: 10.1100/tsw.2006.268] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The candidate tumour-suppressor gene, LUCA-15/RBM5/H37, maps to the lung cancer tumour-suppressor locus 3p21.3. The LUCA-15 gene locus encodes at least four alternatively spliced transcripts that have been shown to function as regulators of apoptosis, a fact which may have major significance in tumour regulation. This review highlights recent evidence that further implicates the LUCA-15 locus in the control of apoptosis and cell proliferation, and focuses on the observations that confirm the tumour-suppressor activity of this gene.
Collapse
Affiliation(s)
- Mirna M Maarabouni
- Institute for Science and Technology in Medicine, Keele University, Keele, Staffs, ST5 5BG, UK.
| | | |
Collapse
|
32
|
Fischer M, Oberthuer A, Brors B, Kahlert Y, Skowron M, Voth H, Warnat P, Ernestus K, Hero B, Berthold F. Differential Expression of Neuronal Genes Defines Subtypes of Disseminated Neuroblastoma with Favorable and Unfavorable Outcome. Clin Cancer Res 2006; 12:5118-28. [PMID: 16951229 DOI: 10.1158/1078-0432.ccr-06-0985] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Identification of molecular characteristics of spontaneously regressing stage IVS and progressing stage IV neuroblastoma to improve discrimination of patients with metastatic disease following favorable and unfavorable clinical courses. EXPERIMENTAL DESIGN Serial analysis of gene expression profiles were generated from five stage IVS and three stage IV neuroblastoma. Differential expression of candidate genes was evaluated by real-time quantitative reverse transcription-PCR in 76 pretreatment tumor samples (stage IVS n=27 and stage IV n=49). Gene expression-based outcome prediction was determined by Prediction Analysis for Microarrays using 38 tumors as a training set and 38 tumors as a test set. RESULTS Comparison of serial analysis of gene expression profiles from stage IV and IVS neuroblastoma revealed approximately 500 differentially expressed transcripts. Genes related to neuronal differentiation were observed more frequently in stage IVS tumors as determined by associating transcripts to Gene Ontology annotations. Forty-one candidate genes were evaluated by quantitative reverse transcription-PCR and 18 were confirmed to be differentially expressed (P<or=0.001). Classification of patients according to expression patterns of these 18 genes using Prediction Analysis for Microarrays discriminated two subgroups with significantly differing event-free survival (96+/-6% versus 40+/-8% at 3 years; P<0.0001) and overall survival (100% versus 72+/-7% at 3 years; P=0.0003). This classifier was the only independent covariate marker in a multivariate analysis considering the variables stage, age, MYCN amplification, and gene signature. CONCLUSIONS Spontaneously regressing and progressing metastatic neuroblastoma differ by specific gene expression patterns, indicating distinct levels of neuronal differentiation and allowing for an improved risk estimation of children with disseminated disease.
Collapse
Affiliation(s)
- Matthias Fischer
- Department of Pediatric Oncology and Hematology and Center of Molecular Medicine Cologne, University Children's Hospital, Germany.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Mourtada-Maarabouni M, Keen J, Clark J, Cooper CS, Williams GT. Candidate tumor suppressor LUCA-15/RBM5/H37 modulates expression of apoptosis and cell cycle genes. Exp Cell Res 2006; 312:1745-52. [PMID: 16546166 DOI: 10.1016/j.yexcr.2006.02.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2005] [Revised: 02/06/2006] [Accepted: 02/08/2006] [Indexed: 11/16/2022]
Abstract
RBM5 (RNA-binding motif protein 5/LUCA-15/H37) is encoded at the lung cancer tumor suppressor locus 3p21.3 and itself has several important characteristics of a tumor suppressor, including both potentiation of apoptosis and inhibition of the cell cycle. Here, we report the effects of both upregulation and downregulation of LUCA-15/RBM5 on gene expression monitored using cDNA microarrays. Many of the genes modulated by LUCA-15/RBM5 are involved in the control of apoptosis, the cell cycle, or both. These effects were confirmed for the most significant genes using real-time RT-PCR and/or Western blotting. In particular, LUCA-15/RBM5 increased the expression of Stat5b and BMP5 and decreased the expression of AIB1 (Amplified In Breast Cancer 1), proto-oncogene Pim-1, caspase antagonist BIRC3 (cIAP-2, MIHC), and CDK2 (cyclin-dependent kinase 2). These effects on multiple genes controlling both apoptosis and proliferation are in line with the functional effects of LUCA-15/RBM5 and indicate that it plays a central role in regulating cell fate consistent with its tumor suppressor activity.
Collapse
|
34
|
Oh JJ, Razfar A, Delgado I, Reed RA, Malkina A, Boctor B, Slamon DJ. 3p21.3 Tumor Suppressor Gene H37/Luca15/RBM5 Inhibits Growth of Human Lung Cancer Cells through Cell Cycle Arrest and Apoptosis. Cancer Res 2006; 66:3419-27. [PMID: 16585163 DOI: 10.1158/0008-5472.can-05-1667] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Deletion at chromosome 3p21.3 is the earliest and the most frequently observed genetic alteration in lung cancer, suggesting that the region contains tumor suppressor gene(s) (TSG). Identification of those genes may lead to the development both of biomarkers to identify high-risk individuals and novel therapeutics. Previously, we cloned the H37/Luca15/RBM5 gene from 3p21.3 and showed its TSG characteristics. To investigate the physiologic function of H37 in the lung and its mechanism of tumor suppression, we have stably transfected H37 into A549 non-small cell lung cancer cells. A549/H37 cells show significant growth inhibition compared with the vector controls by in vitro and in vivo cell proliferation assays. Using this lung cancer cell model, we have found that the molecular mechanism of H37 tumor suppression involves both cell cycle (G(1)) arrest and apoptosis. To further define H37's function in cell cycle/apoptotic pathways, we investigated differential expression profiles of various cell cycle and apoptosis regulatory proteins using Western blot analysis. Both cyclin A and phophorylated RB levels were decreased in H37-transfected cells, whereas expression of Bax protein was increased. Mitochondrial regulation of apoptosis further downstream of Bax was investigated, showing change in the mitochondrial membrane potential, cytochrome c release into the cytosol, and enhanced caspase-9 and caspase-3 activities. We also report that H37 may mediate apoptosis in a p53-independent manner, and Bax knockdown by small interfering RNA suggests Bax plays a functional role downstream of H37. Lastly, we proposed a tumor suppression model of H37 as a post-transcriptional regulator for cell cycle/apoptotic-related proteins.
Collapse
Affiliation(s)
- Juliana J Oh
- Division of Hematology/Oncology, University of California at Los Angeles School of Medicine, 675 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | |
Collapse
|
35
|
Sutherland LC, Rintala-Maki ND, White RD, Morin CD. RNA binding motif (RBM) proteins: a novel family of apoptosis modulators? J Cell Biochem 2005; 94:5-24. [PMID: 15514923 DOI: 10.1002/jcb.20204] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
RBM5 is a known modulator of apoptosis, an RNA binding protein, and a putative tumor suppressor. Originally identified as LUCA-15, and subsequently as H37, it was designated "RBM" (for RNA Binding Motif) due to the presence of two RRM (RNA Recognition Motif) domains within the protein coding sequence. Recently, a number of proteins have been attributed with this same RBM designation, based on the presence of one or more RRM consensus sequences. One such protein, RBM3, was also recently found to have apoptotic modulatory capabilities. The high sequence homology at the amino acid level between RBM5, RBM6, and particularly, RBM10 suggests that they, too, may play an important role in regulating apoptosis. It is the intent of this article to ammalgamate the data on the ten originally identified RBM proteins in order to question the existence of a novel family of RNA binding apoptosis regulators.
Collapse
Affiliation(s)
- Leslie C Sutherland
- Tumour Biology Group, Northeastern Ontario Regional Cancer Centre, 41 Ramsey Lake Road, Sudbury, Ontario P3E 5J1, Canada.
| | | | | | | |
Collapse
|
36
|
Mourtada-Maarabouni M, Kirkham L, Farzaneh F, Williams GT. Functional expression cloning reveals a central role for the receptor for activated protein kinase C 1 (RACK1) in T cell apoptosis. J Leukoc Biol 2005; 78:503-14. [PMID: 15870214 DOI: 10.1189/jlb.0205070] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mammalian cDNA expression cloning was used to identify novel genes that regulate apoptosis. Using a functional screen, we identified a partial cDNA for the receptor for activated protein kinase C 1 (RACK1) through selection for resistance to phytohemagglutinin and gamma-irradiation. Expression of this partial cDNA in T cell lines using a mammalian expression vector produced an increase in RACK1 expression and resulted in resistance to dexamethasone- and ultraviolet-induced apoptosis. Down-regulation of RACK1 using RNA interference abolished the resistance of the transfected cells to apoptosis. Overexpression of full-length RACK1 also resulted in the suppression of apoptosis mediated by several apoptotic stimuli, and this effect was quantitatively consistent with the effects of the original cDNA isolated on endogenous RACK1 levels. Together, these findings suggest that RACK1 plays an important role in the intracellular signaling pathways that lead to apoptosis in T cells.
Collapse
|
37
|
Geigl JB, Langer S, Barwisch S, Pfleghaar K, Lederer G, Speicher MR. Analysis of gene expression patterns and chromosomal changes associated with aging. Cancer Res 2005; 64:8550-7. [PMID: 15574761 DOI: 10.1158/0008-5472.can-04-2151] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Age is the largest single risk factor for the development of cancer in mammals. Age-associated chromosomal changes, such as aneuploidy and telomere erosion, may be vitally involved in the initial steps of tumorigenesis. However, changes in gene expression specific for increased aneuploidy with age have not yet been characterized. Here, we address these questions by using a panel of fibroblast cell lines and lymphocyte cultures from young and old age groups. Oligonucleotide microarrays were used to characterize the expression of 14,500 genes. We measured telomere length and analyzed chromosome copy number changes and structural rearrangements by multicolor interphase fluorescence in situ hybridization and 7-fluorochrome multiplex fluorescence in situ hybridization, and we tried to show a relationship between gene expression patterns and chromosomal changes. These analyses revealed a number of genes involved in both the cell cycle and proliferation that are differently expressed in aged cells. More importantly, our data show an association between age-related aneuploidy and the gene expression level of genes involved in centromere and kinetochore function and in the microtubule and spindle assembly apparatus. To verify that some of these genes may also be involved in tumorigenesis, we compared the expression of these genes in chromosomally stable microsatellite instability and chromosomally unstable chromosomal instability colorectal tumor cell lines. Three genes (Notch2, H2AFY2, and CDC5L) showed similar expression differences between microsatellite instability and chromosomal instability cell lines as observed between the young and old cell cultures suggesting that they may play a role in tumorigenesis.
Collapse
Affiliation(s)
- Jochen B Geigl
- Institute of Human Genetics, Technical University, Munich, Germany
| | | | | | | | | | | |
Collapse
|
38
|
Callebaut I, Mornon JP. OCRE: a novel domain made of imperfect, aromatic-rich octamer repeats. Bioinformatics 2004; 21:699-702. [PMID: 15486042 DOI: 10.1093/bioinformatics/bti065] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
SUMMARY In this study, we describe a novel domain, OCRE, which is shared by the recently identified angiogenic factor VG5Q and a specific family of RNA-binding motif proteins. The OCRE domain is characterized by a 5-fold, imperfectly repeated octameric sequence, which includes a triplet of often-conserved aromatic amino acids predicted to form a beta-strand and in which the slightly modified fifth repeat might act as a repeat terminator. Although the function of this domain remains to be elucidated, the domain architecture of OCRE containing proteins and experimental data suggest a role in RNA metabolism and/or in signalling pathways activated by the tumor necrosis factor superfamily of cytokines.
Collapse
Affiliation(s)
- Isabelle Callebaut
- Département de Biologie Structurale, LMCP, CNRS UMR7590, Universités Paris 6 & Paris 7, Case 115, 4 place Jussieu, 75252 Paris Cedex 05, France. Isabelle.
| | | |
Collapse
|