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Zhu N, Zhao Y, Yan W, Wei L, Sang Q, Li J, Liu B, Yu B. Characterization of alternative splicing events and prognostic signatures in gastric cancer. Cancer Cell Int 2024; 24:167. [PMID: 38734676 PMCID: PMC11088037 DOI: 10.1186/s12935-024-03348-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 04/28/2024] [Indexed: 05/13/2024] Open
Abstract
BACKGROUND Accumulating evidences indicate that the specific alternative splicing (AS) events are linked to the occurrence and prognosis of gastric cancer (GC). Nevertheless, the impact of AS is still unclear and needed to further elucidation. METHODS The expression profile of GC and normal samples were downloaded from TCGA. AS events were achieved from SpliceSeq database. Cox regression together with LASSO analysis were employed to identify survival-associated AS events (SASEs) and calculate risk scores. PPI and pathway enrichment analysis were implemented to determine the function and pathways of these genes. Kaplan-Meier (K-M) analysis and Receiver Operating Characteristic Curves were used to evaluate the clinical significance of genes of SASEs. Q-PCR were applied to validate the hub genes on the survival prognosis in 47 GC samples. Drug sensitivity and immune cell infiltration analysis were conducted. RESULTS In total, 48 140 AS events in 10 610 genes from 361 GC and 31 normal samples were analyzed. Through univariate Cox regression, 855 SASEs in 763 genes were screened out. Further, these SASEs were analyzed by PPI and 17 hub genes were identified. Meanwhile, using Lasso and multivariate Cox regression analysis, 135 SASEs in 132 genes related to 7 AS forms were further screened and a GC prognostic model was constructed. K-M curves indicates that high-risk group has poorer prognosis. And the nomogram analysis on the basis of the multivariate Cox analysis was disclosed the interrelationships between 7 AS forms and clinical parameters in the model. Five key genes were then screened out by PPI analysis and Differential Expression Gene analysis based on TCGA and Combined-dataset, namely STAT3, RAD51B, SOCS2, POLE2 and TSR1. The expression levels of AS in STAT3, RAD51B, SOCS2, POLE2 and TSR1 were all significantly correlated with survival by qPCR verification. Nineteen drugs were sensitized to high-risk patients and eight immune cells showed significantly different infiltration between the STAD and normal groups. CONCLUSIONS In this research, the prognostic model constructed by SASEs can be applied to predict the prognosis of GC patients and the selected key genes are expected to become new biomarkers and therapeutical targets for GC treatment.
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Affiliation(s)
- Nan Zhu
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yupeng Zhao
- Gastroenterological Surgery, The affiliated Wuxi No. 2, People's Hospital of Nanjing Medical University, Wuxi, 200240, China
| | - Wenjing Yan
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Lan Wei
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qingqing Sang
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jianfang Li
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Bingya Liu
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Beiqin Yu
- Department of General Surgery, Shanghai Key Laboratory of Gastric Neoplasms, Shanghai Institute of Digestive Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Malki I, Liepina I, Kogelnik N, Watmuff H, Robinson S, Lightfoot A, Gonchar O, Bottrill A, Fry AM, Dominguez C. Cdk1-mediated threonine phosphorylation of Sam68 modulates its RNA binding, alternative splicing activity and cellular functions. Nucleic Acids Res 2022; 50:13045-13062. [PMID: 36537190 PMCID: PMC9825155 DOI: 10.1093/nar/gkac1181] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Sam68, also known as KHDRBS1, is a member of the STAR family of proteins that directly link signal transduction with post-transcriptional gene regulation. Sam68 controls the alternative splicing of many oncogenic proteins and its role is modulated by post-translational modifications, including serine/threonine phosphorylation, that differ at various stages of the cell cycle. However, the molecular basis and mechanisms of these modulations remain largely unknown. Here, we combined mass spectrometry, nuclear magnetic resonance spectroscopy and cell biology techniques to provide a comprehensive post-translational modification mapping of Sam68 at different stages of the cell cycle in HEK293 and HCT116 cells. We established that Sam68 is specifically phosphorylated at T33 and T317 by Cdk1, and demonstrated that these phosphorylation events reduce the binding of Sam68 to RNA, control its cellular localization and reduce its alternative splicing activity, leading to a reduction in the induction of apoptosis and an increase in the proliferation of HCT116 cells.
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Affiliation(s)
- Idir Malki
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Inara Liepina
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Nora Kogelnik
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Hollie Watmuff
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Sue Robinson
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Adam Lightfoot
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Oksana Gonchar
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Andrew Bottrill
- Proteomics RTP, School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK
| | - Andrew M Fry
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Cyril Dominguez
- The Leicester Institute of Structural and Chemical Biology and Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 7RH, UK
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DNA Damage Regulates the Functions of the RNA Binding Protein Sam68 through ATM-Dependent Phosphorylation. Cancers (Basel) 2022; 14:cancers14163847. [PMID: 36010841 PMCID: PMC9405969 DOI: 10.3390/cancers14163847] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/26/2022] [Accepted: 08/05/2022] [Indexed: 12/11/2022] Open
Abstract
Simple Summary Alterations of the complex network of interactions between the DNA damage response pathway and RNA metabolism have been described in several tumors, and increasing efforts are devoted to the elucidation of the molecular mechanisms involved in this network. Previous large-scale proteomic studies identified the RNA binding protein Sam68 as a putative target of the ATM kinase. Herein, we demonstrate that ATM phosphorylates Sam68 upon DNA damage induction, and this post-translational modification regulates both the signaling function of Sam68 in the initial phase of the DNA damage response and its RNA processing activity. Thus, our study uncovers anew crosstalk between ATM and Sam68, which may represent a paradigm for the functional interaction between the DDR pathway and RNA binding proteins, and a possible actionabletarget in human cancers. Abstract Cancer cells frequently exhibit dysregulation of the DNA damage response (DDR), genomic instability, and altered RNA metabolism. Recent genome-wide studies have strongly suggested an interaction between the pathways involved in the cellular response to DDR and in the regulation of RNA metabolism, but the molecular mechanism(s) involved in this crosstalk are largely unknown. Herein, we found that activation of the DDR kinase ATM promotes its interaction with Sam68, leading to phosphorylation of this multifunctional RNA binding protein (RBP) on three residues: threonine 61, serine 388 and serine 390. Moreover, we demonstrate that ATM-dependent phosphorylation of threonine 61 promotes the function of Sam68 in the DDR pathway and enhances its RNA processing activity. Importantly, ATM-mediated phosphorylation of Sam68 in prostate cancer cells modulates alternative polyadenylation of transcripts that are targets of Sam68, supporting the notion that the ATM–Sam68 axis exerts a multifaceted role in the response to DNA damage. Thus, our work validates Sam68 as an ATM kinase substrate and uncovers an unexpected bidirectional interplay between ATM and Sam68, which couples the DDR pathway to modulation of RNA metabolism in response to genotoxic stress.
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Naro C, Barbagallo F, Caggiano C, De Musso M, Panzeri V, Di Agostino S, Paronetto MP, Sette C. Functional Interaction Between the Oncogenic Kinase NEK2 and Sam68 Promotes a Splicing Program Involved in Migration and Invasion in Triple-Negative Breast Cancer. Front Oncol 2022; 12:880654. [PMID: 35530315 PMCID: PMC9068942 DOI: 10.3389/fonc.2022.880654] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 03/16/2022] [Indexed: 12/01/2022] Open
Abstract
Triple-negative breast cancer (TNBC) represents the most aggressive breast cancer subtype. Poor prognosis in TNBC is partly due to lack of efficacious targeted therapy and high propensity to metastasize. Dysregulation of alternative splicing has recently emerged as a trait of TNBC, suggesting that unveiling the molecular mechanisms underlying its regulation could uncover new druggable cancer vulnerabilities. The oncogenic kinase NEK2 is significantly upregulated in TNBC and contributes to shaping their unique splicing profile. Herein, we found that NEK2 interacts with the RNA binding protein Sam68 in TNBC cells and that NEK2-mediated phosphorylation of Sam68 enhances its splicing activity. Genome-wide transcriptome analyses identified the splicing targets of Sam68 in TNBC cells and revealed a common set of exons that are co-regulated by NEK2. Functional annotation of splicing-regulated genes highlighted cell migration and spreading as biological processes regulated by Sam68. Accordingly, Sam68 depletion reduces TNBC cell migration and invasion, and these effects are potentiated by the concomitant inhibition of NEK2 activity. Our findings indicate that Sam68 and NEK2 functionally cooperate in the regulation of a splicing program that sustains the pro-metastatic features of TNBC cells.
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Affiliation(s)
- Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, University of the Sacred Hearth, Rome, Italy.,Gemelli SCIENCE and TECHNOLOGY PARK (GSTeP)-Organoids Research Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy
| | - Federica Barbagallo
- Department of Experimental Medicine, University of Rome Sapienza, Rome, Italy
| | - Cinzia Caggiano
- Department of Neuroscience, Section of Human Anatomy, University of the Sacred Hearth, Rome, Italy.,Gemelli SCIENCE and TECHNOLOGY PARK (GSTeP)-Organoids Research Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy
| | - Monica De Musso
- Department of Neuroscience, Section of Human Anatomy, University of the Sacred Hearth, Rome, Italy
| | - Valentina Panzeri
- Department of Neuroscience, Section of Human Anatomy, University of the Sacred Hearth, Rome, Italy.,Gemelli SCIENCE and TECHNOLOGY PARK (GSTeP)-Organoids Research Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy
| | - Silvia Di Agostino
- Department of Health Sciences, "Magna Graecia" University of Catanzaro, Catanzaro, Italy
| | - Maria Paola Paronetto
- Department of Movement, Human and Health Sciences, University of Rome Foro Italico, Rome, Italy.,Laboratory of Molecular and Cellular Neurobiology, Fondazione Santa Lucia IRCCS, Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, University of the Sacred Hearth, Rome, Italy.,Gemelli SCIENCE and TECHNOLOGY PARK (GSTeP)-Organoids Research Core Facility, Fondazione Policlinico Agostino Gemelli IRCCS, Rome, Italy
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5
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Parulekar A, Choksi A, Taye N, Totakura KVS, Firmal P, Kundu GC, Chattopadhyay S. SMAR1 suppresses the cancer stem cell population via hTERT repression in colorectal cancer cells. Int J Biochem Cell Biol 2021; 141:106085. [PMID: 34551340 DOI: 10.1016/j.biocel.2021.106085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 09/09/2021] [Accepted: 09/16/2021] [Indexed: 11/25/2022]
Abstract
One of the hallmarks of a cancer cell is the ability for indefinite proliferation leading to the immortalization of the cell. Activation of several signaling pathways leads to the immortalization of cancer cells via the reactivation of enzyme telomerase (hTERT). hTERT is active in germ cells, stem cells and also cancer cells. An earlier report from our lab suggests that SMAR1, a tumor suppressor protein, is significantly downregulated in the higher grades of colorectal cancers. Our study identifies SMAR1 as a transcriptional repressor of hTERT. We find that SMAR1 interacts with HDAC1/mSin3a co-repressor complex at the hTERT promoter and brings about HDAC1-mediated transcriptional repression of the promoter. Most solid tumors including colorectal cancer reactivate hTERT expression as it confers several advantages to the cancer cells like increased proliferation and angiogenesis. One of these non-canonical functions of hTERT is inducing the pool of cancer stem cell population. We find that in the CD133HighCD44High cancer stem cells population, SMAR1 expression is highly diminished leading to elevated hTERT expression. We also find that knockdown of SMAR1 promotes total CD133+CD44+ population and impart enhanced sphere-forming ability to the colorectal cancer cells. SMAR1 also inhibits invasion and metastasis in colorectal cancer cell lines via repression of hTERT. Our study provides evidence that downregulation of SMAR1 causes activation of hTERT leading to an increase in the cancer stem cell phenotype in colorectal cancer cells.
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Affiliation(s)
| | | | | | | | | | - Gopal C Kundu
- National Centre for Cell Science, Pune, India; Kalinga Institute of Industrial Technology, Bhubaneswar, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, India; Birla Institute of Technology and Science, Goa, India.
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Firmal P, Shah VK, Pant R, Chattopadhyay S. RING finger protein TOPORS modulates the expression of tumor suppressor SMAR1 in colorectal cancer via the TLR4-TRIF pathway. Mol Oncol 2021; 16:1523-1540. [PMID: 34689394 PMCID: PMC8978522 DOI: 10.1002/1878-0261.13126] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
TOP1‐binding arginine/serine‐rich protein (TOPORS), a really interesting new gene finger protein, has the ability to bind to a palindromic consensus DNA sequence that enables it to function as a potential transcriptional regulator. However, its role in regulating the transcription of cancer‐associated genes is yet to be explored. As Toll‐like receptor 4 (TLR4) agonists are known to regress solid tumors, we observed that lipopolysaccharide (LPS) induces TOPORS via a TLR4‐TIR domain‐containing adapter‐inducing interferon‐β‐dependent pathway, which in turn modulates the transcription of tumor suppressor scaffold/matrix attachment region‐binding protein 1 (SMAR1, also known as BANP). ChIP analysis showed that TOPORS binds on the SMAR1 promoter and its occupancy increases upon LPS treatment. A previous study from our laboratory revealed that SMAR1 acts as a repressor of signal transducer and activator of transcription 3 (STAT3) transcription. Tumor growth, as well as tumor‐associated macrophage polarization, depends on the status of the STAT1:STAT3 ratio. LPS‐induced SMAR1 expression decreases STAT3 expression and also skews the macrophage polarization toward M1 phenotype. In contrast, LPS failed to polarize tumor‐associated macrophages to M1 phenotype in a SMAR1‐silenced condition, which shows the involvement of SMAR1 in dictating the fate of colorectal cancer progression. Identification of the molecular mechanism behind LPS‐mediated tumor regression would be crucial for designing cancer treatment strategies involving bacterial components.
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Affiliation(s)
- Priyanka Firmal
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007
| | - Vibhuti Kumar Shah
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007
| | - Richa Pant
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007
| | - Samit Chattopadhyay
- National Centre for Cell Science, S.P. Pune University Campus, Ganeshkhind, Pune, 411007.,Department of Biological Sciences, BITS Pilani, K. K. Birla Goa Campus, NH 17B, Zuarinagar, Goa, 403726.,Indian Institute of Chemical Biology, Raja S C Mullick Road, Jadavpur, Kolkata, 700032
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7
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Ruta V, Pagliarini V, Sette C. Coordination of RNA Processing Regulation by Signal Transduction Pathways. Biomolecules 2021; 11:biom11101475. [PMID: 34680108 PMCID: PMC8533259 DOI: 10.3390/biom11101475] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/01/2021] [Accepted: 10/05/2021] [Indexed: 02/06/2023] Open
Abstract
Signal transduction pathways transmit the information received from external and internal cues and generate a response that allows the cell to adapt to changes in the surrounding environment. Signaling pathways trigger rapid responses by changing the activity or localization of existing molecules, as well as long-term responses that require the activation of gene expression programs. All steps involved in the regulation of gene expression, from transcription to processing and utilization of new transcripts, are modulated by multiple signal transduction pathways. This review provides a broad overview of the post-translational regulation of factors involved in RNA processing events by signal transduction pathways, with particular focus on the regulation of pre-mRNA splicing, cleavage and polyadenylation. The effects of several post-translational modifications (i.e., sumoylation, ubiquitination, methylation, acetylation and phosphorylation) on the expression, subcellular localization, stability and affinity for RNA and protein partners of many RNA-binding proteins are highlighted. Moreover, examples of how some of the most common signal transduction pathways can modulate biological processes through changes in RNA processing regulation are illustrated. Lastly, we discuss challenges and opportunities of therapeutic approaches that correct RNA processing defects and target signaling molecules.
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Affiliation(s)
- Veronica Ruta
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Vittoria Pagliarini
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Organoids Facility, IRCCS Fondazione Policlinico Universitario Agostino Gemelli, 00168 Rome, Italy
| | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168 Rome, Italy; (V.R.); (V.P.)
- Laboratory of Neuroembryology, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
- Correspondence:
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8
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Pant R, Alam A, Choksi A, Shah VK, Firmal P, Chattopadhyay S. Chromatin remodeling protein SMAR1 regulates adipogenesis by modulating the expression of PPARγ. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159045. [PMID: 34450266 DOI: 10.1016/j.bbalip.2021.159045] [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: 02/19/2021] [Revised: 08/15/2021] [Accepted: 08/21/2021] [Indexed: 11/17/2022]
Abstract
Adipogenesis is described as the process of conversion of pre-adipocytes into differentiated lipid-laden adipocytes. Adipogenesis is known to be regulated by a myriad of transcription factors and co-regulators. However, there is a dearth of information regarding the mechanisms that regulate these transcription factors and hence control adipogenesis. PPARγ is the master transcriptional regulator of adipogenesis and its expression is essential for adipocyte differentiation. Herein, we identified that scaffold/matrix attachment region-binding protein 1 (SMAR1) negatively regulates adipogenesis. We observed that SMAR1 gets downregulated during adipocyte differentiation and knockdown of SMAR1 promotes lipid accumulation and adipocyte differentiation. Mechanistically, we have shown that SMAR1 suppresses PPARγ through recruitment of the HDAC1/mSin3a repressor complex to the PPARγ promoter. We further identified cell division cycle 20 (cdc20) mediated proteasomal degradation of SMAR1 during adipogenesis. Moreover, knockdown of cdc20 resulted in stabilization of SMAR1 and a reduction in adipocyte differentiation. Taken together, our observations suggest that SMAR1 functions as a negative regulator of adipogenesis by inhibiting PPARγ expression in differentiating adipocytes.
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Affiliation(s)
- Richa Pant
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India.
| | - Aftab Alam
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India; Roswell Park Comprehensive Cancer Center, Buffalo, NY 14203, United States of America
| | - Arpankumar Choksi
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Vibhuti Kumar Shah
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Priyanka Firmal
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, S P Pune University Campus, Ganeshkhind, Pune 411007, India; Department of Biological Sciences, BITS Pilani, K. K. Birla Goa Campus, NH 17B, Zuarinagar, Goa 403726, India; Indian Institute of Chemical Biology; 4, Raja S C Mullick Road, Jadavpur, Kolkata 700032, India.
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9
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Gomes ID, Ariyaratne UV, Pflum MKH. HDAC6 Substrate Discovery Using Proteomics-Based Substrate Trapping: HDAC6 Deacetylates PRMT5 to Influence Methyltransferase Activity. ACS Chem Biol 2021; 16:1435-1444. [PMID: 34314149 DOI: 10.1021/acschembio.1c00303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Histone deacetylase 6 (HDAC6) is upregulated in a variety of tumor cell lines and has been linked to many cellular processes, such as cell signaling, protein degradation, cell survival, and cell motility. HDAC6 is an enzyme that deacetylates the acetyllysine residues of protein substrates, and the discovery of HDAC6 substrates, including tubulin, has revealed many roles of HDAC6 in cell biology. Unfortunately, among the wide variety of acetylated proteins in the cell, only a few are verified as HDAC6 substrates, which limits the full characterization of HDAC6 cellular functions. Substrate trapping mutants were recently established as a tool to discover unanticipated substrates of histone deacetylase 1 (HDAC1). In this study, we applied the trapping approach to identify potential HDAC6 substrates. Among the high confidence protein hits after trapping, protein arginine methyl transferase 5 (PRMT5) was successfully validated as a novel HDAC6 substrate. PRMT5 acetylation enhanced its methyltransferase activity and symmetrical dimethylation of downstream substrates, revealing possible crosstalk between acetylation and methylation. Substrate trapping represents a powerful, systematic, and unbiased approach to discover substrates of HDAC6.
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Affiliation(s)
- Inosha D. Gomes
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Udana V. Ariyaratne
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Mary Kay H. Pflum
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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Liu H, Hu L, Yu G, Yang H, Cao Y, Wang S, Fan Z. LncRNA, PLXDC2-OT promoted the osteogenesis potentials of MSCs by inhibiting the deacetylation function of RBM6/SIRT7 complex and OSX specific isoform. Stem Cells 2021; 39:1049-1066. [PMID: 33684230 DOI: 10.1002/stem.3362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 02/10/2021] [Indexed: 11/10/2022]
Abstract
Bone regeneration and remodeling are complex physiological processes that are regulated by key transcription factors. Understanding the regulatory mechanism of key transcription factors on the osteogenic differentiation of mesenchymal stem cells (MSCs) is a key issue for successful bone regeneration and remodeling. In the present study, we investigated the regulatory mechanism of the histone deacetylase Sirtuin 7 (SIRT7) on the key transcription factor OSX and osteogenesis of MSCs. In this study, we found that SIRT7 knockdown increased ALP activity and in vitro mineralization and promoted the expression of the osteogenic differentiation markers DSPP, DMP1, BSP, OCN, and the key transcription factor OSX in MSCs. In addition, SIRT7 could associate with RNA binding motif protein 6 (RBM6) to form a protein complex. Moreover, RBM6 inhibited ALP activity, the expression of DSPP, DMP1, BSP, OCN, and OSX in MSCs, and the osteogenesis of MSCs in vivo. Then, the SIRT7/RBM6 protein complex was shown to downregulate the level of H3K18Ac in the OSX promoter by recruiting SIRT7 to the OSX promoter and inhibiting the expression of OSX isoforms 1 and 2. Furthermore, lncRNA PLXDC2-OT could associate with the SIRT7/RBM6 protein complex to diminish its binding and deacetylation function in the OSX promoter and its inhibitory function on OSX isoforms 1 and 2 and to promote the osteogenic potential of MSCs.
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Affiliation(s)
- Huina Liu
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
| | - Lei Hu
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
| | - Guoxia Yu
- Department of Stomatology, Beijing Children's Hospital, Capital Medical University, Beijing, People's Republic of China
| | - Haoqing Yang
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
| | - Yangyang Cao
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
| | - Songlin Wang
- Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
- Department of Biochemistry and Molecular Biology, Capital Medical University School of Basic Medical Sciences, Beijing, People's Republic of China
| | - Zhipeng Fan
- Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, People's Republic of China
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11
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Xu H, Liu T, Li W, Yao Q. SMAR1 attenuates the stemness of osteosarcoma cells via through suppressing ABCG2 transcriptional activity. ENVIRONMENTAL TOXICOLOGY 2021; 36:1090-1098. [PMID: 33543840 DOI: 10.1002/tox.23108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/16/2021] [Accepted: 01/24/2021] [Indexed: 06/12/2023]
Abstract
The promoting roles of the transcriptional regulator SMAR1 have been revealed in several tumors, such as colorectal and breast cancer, however, its roles in osteosarcoma (OS) progression are still confusing. Here, we find that SMAR1 expression is positively correlated with the overall survival of OS patients and negatively correlated with the expression of stemness markers by analyzing the online datasets. Through analyzing different Gene Expression Omnibus (GEO) datasets, SMAR1 is found to be lowly expressed in OS tissues relative to that in adjacent tissues. Functional experiments indicate that SMAR1 overexpression attenuates the stemness of OS cells, characterized as the decrease of stemness marker expression, sphere-formation ability and ALDH activity. Mechanistically, it is shown that SMAR1 increases the deacetylation level of the drug efflux pump ABCG2 via recruiting HDAC2 to the promoter of the gene coding ABCG2, and thus decreases ABCG2 transcriptional activity. Additionally, overexpression of ABCG2 rescues the inhibition of SMAR1 overexpression on the stemness of OS cells. Moreover, this SMAR1/ABCG2 axis positively regulates the chemotherapeutic sensitivity of OS cells. This work indicates that SMAR1 is a critical suppressor for OS progression through transcriptionally regulating ABCG2 expression.
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Affiliation(s)
- Hongyu Xu
- Department of Geriatric Medicine, Ningbo First Hospital, Ningbo, China
| | - Ting Liu
- Department of Geriatric Medicine, Ningbo First Hospital, Ningbo, China
| | - Wenjie Li
- Department of Geriatric Medicine, Ningbo First Hospital, Ningbo, China
| | - Qi Yao
- Department of Geriatric Medicine, Ningbo First Hospital, Ningbo, China
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12
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Choksi A, Parulekar A, Pant R, Shah VK, Nimma R, Firmal P, Singh S, Kundu GC, Shukla S, Chattopadhyay S. Tumor suppressor SMAR1 regulates PKM alternative splicing by HDAC6-mediated deacetylation of PTBP1. Cancer Metab 2021; 9:16. [PMID: 33863392 PMCID: PMC8052847 DOI: 10.1186/s40170-021-00252-x] [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: 01/18/2021] [Accepted: 03/30/2021] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Highly proliferating cancer cells exhibit the Warburg effect by regulation of PKM alternative splicing and promoting the expression of PKM2. Majority of the alternative splicing events are known to occur in the nuclear matrix where various MARBPs actively participate in the alternative splicing events. SMAR1, being a MARBP and an important tumor suppressor, is known to regulate the splicing of various cancer-associated genes. This study focuses on the regulation of PKM alternative splicing and inhibition of the Warburg effect by SMAR1. METHODS Immunohistochemistry was performed in breast cancer patient samples to establish the correlation between SMAR1 and PKM isoform expression. Further, expression of PKM isoforms upon modulation in SMAR1 expression in breast cancer cell lines was quantified by qRT-PCR and western blot. The acetylation status of PTBP1 was estimated by immunoprecipitation along with its enrichment on PKM pre-mRNA by CLIP in SMAR1 knockdown conditions. The role of SMAR1 in tumor metabolism and tumorigenesis was explored by in vitro enzymatic assays and functional assays upon SMAR1 knockdown. Besides, in vivo tumor formation by injecting adeno-SMAR1-transduced MDA-MB-231 cells in NOD/SCID mice was performed. RESULTS The expression profile of SMAR1 and PKM isoforms in breast cancer patients revealed that SMAR1 has an inverse correlation with PKM2 and a positive correlation with PKM1. Further quantitative PKM isoform expression upon modulation in SMAR1 expression also reflects that SMAR1 promotes the expression of PKM1 over tumorigenic isoform PKM2. SMAR1 deacetylates PTBP1 via recruitment of HDAC6 resulting in reduced enrichment of PTBP1 on PKM pre-mRNA. SMAR1 inhibits the Warburg effect, tumorigenic potential of cancer cells, and in vivo tumor generation in a PKM2-dependent manner. CONCLUSIONS SMAR1 regulates PKM alternative splicing by causing HDAC6-dependent deacetylation of PTBP1, resulting in reduced enrichment of PTBP1 on PKM pre-mRNA. Additionally, SMAR1 suppresses glucose utilization and lactate production via repression of PKM2 expression. This suggests that tumor suppressor SMAR1 inhibits tumor cell metabolism and tumorigenic properties of cancer cells via regulation of PKM alternative splicing.
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Affiliation(s)
| | | | - Richa Pant
- National Centre for Cell Science, Pune, 411007, India
| | | | | | | | - Smriti Singh
- Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Gopal C Kundu
- National Centre for Cell Science, Pune, 411007, India.,Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, 751024, India
| | - Sanjeev Shukla
- Indian Institute of Science Education and Research, Bhopal, 462066, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, 411007, India. .,Birla Institute of Technology and Science, Pilani - K K Birla Goa Campus, Goa, 403726, India.
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13
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Bhattacharya A, Mukherjee S, Khan P, Banerjee S, Dutta A, Banerjee N, Sengupta D, Basak U, Chakraborty S, Dutta A, Chattopadhyay S, Jana K, Sarkar DK, Chatterjee S, Das T. SMAR1 repression by pluripotency factors and consequent chemoresistance in breast cancer stem-like cells is reversed by aspirin. Sci Signal 2020; 13:13/654/eaay6077. [PMID: 33082288 DOI: 10.1126/scisignal.aay6077] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The high abundance of drug efflux pumps in cancer stem cells (CSCs) contributes to chemotherapy resistance. The transcriptional regulator SMAR1 suppresses CSC expansion in colorectal cancer, and increased abundance of SMAR1 is associated with better prognosis. Here, we found in breast tumors that the expression of SMAR1 was decreased in CSCs through the cooperative interaction of the pluripotency factors Oct4 and Sox2 with the histone deacetylase HDAC1. Overexpressing SMAR1 sensitized CSCs to chemotherapy through SMAR1-dependent recruitment of HDAC2 to the promoter of the gene encoding the drug efflux pump ABCG2. Treating cultured CSCs or 4T1 tumor-bearing mice with the nonsteroidal anti-inflammatory drug aspirin restored SMAR1 expression and ABCG2 repression and enhanced tumor sensitivity to doxorubicin. Our findings reveal transcriptional mechanisms regulating SMAR1 that also regulate cancer stemness and chemoresistance and suggest that, by restoring SMAR1 expression, aspirin might enhance chemotherapeutic efficacy in patients with stem-like tumors.
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Affiliation(s)
- Apoorva Bhattacharya
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Shravanti Mukherjee
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Poulami Khan
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Shruti Banerjee
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Apratim Dutta
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Nilanjan Banerjee
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Debomita Sengupta
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Udit Basak
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Sourio Chakraborty
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Abhishek Dutta
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Samit Chattopadhyay
- Department of Biological Sciences, BITS-Pilani, K K Birla Goa Campus, NH 17B, Zuarinagar, Goa-403 726, India
| | - Kuladip Jana
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Diptendra K Sarkar
- Department of Surgery, IPGMER and SSKM Hospital, Kolkata- 700 020, India
| | - Subhrangsu Chatterjee
- Department of Biophysics, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India
| | - Tanya Das
- Division of Molecular Medicine, Bose Institute, P-1/12 CIT Scheme VII M, Kolkata-700 054, India.
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14
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Kang D, Lee Y, Lee JS. RNA-Binding Proteins in Cancer: Functional and Therapeutic Perspectives. Cancers (Basel) 2020; 12:cancers12092699. [PMID: 32967226 PMCID: PMC7563379 DOI: 10.3390/cancers12092699] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Simple Summary RNA-binding proteins (RBPs) play central roles in regulating posttranscriptional expression of genes. Many of them are known to be deregulated in a wide variety of cancers. Dysregulated RBPs influence the expression levels of target RNAs related to cancer phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and EMT/invasion/metastasis. Thus, understanding the molecular functions of RBPs and their roles in cancer-related phenotypes can lead to improved therapeutic strategies. Abstract RNA-binding proteins (RBPs) crucially regulate gene expression through post-transcriptional regulation, such as by modulating microRNA (miRNA) processing and the alternative splicing, alternative polyadenylation, subcellular localization, stability, and translation of RNAs. More than 1500 RBPs have been identified to date, and many of them are known to be deregulated in cancer. Alterations in the expression and localization of RBPs can influence the expression levels of oncogenes, tumor-suppressor genes, and genome stability-related genes. RBP-mediated gene regulation can lead to diverse cancer-related cellular phenotypes, such as proliferation, apoptosis, angiogenesis, senescence, and epithelial-mesenchymal transition (EMT)/invasion/metastasis. This regulation can also be associated with cancer prognosis. Thus, RBPs can be potential targets for the development of therapeutics for the cancer treatment. In this review, we describe the molecular functions of RBPs, their roles in cancer-related cellular phenotypes, and various approaches that may be used to target RBPs for cancer treatment.
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Affiliation(s)
- Donghee Kang
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
| | - Yerim Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
| | - Jae-Seon Lee
- Medical Research Center, College of Medicine, Inha University, Incheon 22212, Korea; (D.K.); (Y.L.)
- Department of Molecular Medicine, College of Medicine, Inha University, Incheon 22212, Korea
- Program in Biomedical Science & Engineering, Inha University Graduate School, Incheon 22212, Korea
- Correspondence: ; Tel.: +82-32-860-9832
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15
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Qin H, Ni H, Liu Y, Yuan Y, Xi T, Li X, Zheng L. RNA-binding proteins in tumor progression. J Hematol Oncol 2020; 13:90. [PMID: 32653017 PMCID: PMC7353687 DOI: 10.1186/s13045-020-00927-w] [Citation(s) in RCA: 161] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/25/2020] [Indexed: 02/08/2023] Open
Abstract
RNA-binding protein (RBP) has a highly dynamic spatiotemporal regulation process and important biological functions. They are critical to maintain the transcriptome through post-transcriptionally controlling the processing and transportation of RNA, including regulating RNA splicing, polyadenylation, mRNA stability, mRNA localization, and translation. Alteration of each process will affect the RNA life cycle, produce abnormal protein phenotypes, and thus lead to the occurrence and development of tumors. Here, we summarize RBPs involved in tumor progression and the underlying molecular mechanisms whereby they are regulated and exert their effects. This analysis is an important step towards the comprehensive characterization of post-transcriptional gene regulation involved in tumor progression.
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Affiliation(s)
- Hai Qin
- School of Life Science and Technology, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, People's Republic of China
| | - Haiwei Ni
- School of Life Science and Technology, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, People's Republic of China
| | - Yichen Liu
- School of Life Science and Technology, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, People's Republic of China
| | - Yaqin Yuan
- Guizhou Medical Device Testing Center, Guiyang, 550004, Guizhou, People's Republic of China
| | - Tao Xi
- School of Life Science and Technology, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, People's Republic of China.
| | - Xiaoman Li
- Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, People's Republic of China.
| | - Lufeng Zheng
- School of Life Science and Technology, Jiangsu Key Laboratory of Carcinogenesis and Intervention, China Pharmaceutical University, 639 Longmian Road, Nanjing, 211198, People's Republic of China.
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16
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Roles of Splicing Factors in Hormone-Related Cancer Progression. Int J Mol Sci 2020; 21:ijms21051551. [PMID: 32106418 PMCID: PMC7084890 DOI: 10.3390/ijms21051551] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 02/20/2020] [Indexed: 12/19/2022] Open
Abstract
Splicing of mRNA precursor (pre-mRNA) is a mechanism to generate multiple mRNA isoforms from a single pre-mRNA, and it plays an essential role in a variety of biological phenomena and diseases such as cancers. Previous studies have demonstrated that cancer-specific splicing events are involved in various aspects of cancers such as proliferation, migration and response to hormones, suggesting that splicing-targeting therapy can be promising as a new strategy for cancer treatment. In this review, we focus on the splicing regulation by RNA-binding proteins including Drosophila behavior/human splicing (DBHS) family proteins, serine/arginine-rich (SR) proteins and heterogeneous nuclear ribonucleoproteins (hnRNPs) in hormone-related cancers, such as breast and prostate cancers.
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17
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HDAC6-an Emerging Target Against Chronic Myeloid Leukemia? Cancers (Basel) 2020; 12:cancers12020318. [PMID: 32013157 PMCID: PMC7072136 DOI: 10.3390/cancers12020318] [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: 01/06/2020] [Revised: 01/23/2020] [Accepted: 01/27/2020] [Indexed: 02/06/2023] Open
Abstract
Imatinib became the standard treatment for chronic myeloid leukemia (CML) about 20 years ago, which was a major breakthrough in stabilizing the pathology and improving the quality of life of patients. However, the emergence of resistance to imatinib and other tyrosine kinase inhibitors leads researchers to characterize new therapeutic targets. Several studies have highlighted the role of histone deacetylase 6 (HDAC6) in various pathologies, including cancer. This protein effectively intervenes in cellular activities by its primarily cytoplasmic localization. In this review, we will discuss the molecular characteristics of the HDAC6 protein, as well as its overexpression in CML leukemic stem cells, which make it a promising therapeutic target for the treatment of CML.
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18
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Nimeth BA, Riegler S, Kalyna M. Alternative Splicing and DNA Damage Response in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:91. [PMID: 32140165 PMCID: PMC7042379 DOI: 10.3389/fpls.2020.00091] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 01/21/2020] [Indexed: 05/06/2023]
Abstract
Plants are exposed to a variety of abiotic and biotic stresses that may result in DNA damage. Endogenous processes - such as DNA replication, DNA recombination, respiration, or photosynthesis - are also a threat to DNA integrity. It is therefore essential to understand the strategies plants have developed for DNA damage detection, signaling, and repair. Alternative splicing (AS) is a key post-transcriptional process with a role in regulation of gene expression. Recent studies demonstrate that the majority of intron-containing genes in plants are alternatively spliced, highlighting the importance of AS in plant development and stress response. Not only does AS ensure a versatile proteome and influence the abundance and availability of proteins greatly, it has also emerged as an important player in the DNA damage response (DDR) in animals. Despite extensive studies of DDR carried out in plants, its regulation at the level of AS has not been comprehensively addressed. Here, we provide some insights into the interplay between AS and DDR in plants.
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19
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Chen T, Zheng W, Chen J, Lin S, Zou Z, Li X, Tan Z. Systematic analysis of survival-associated alternative splicing signatures in clear cell renal cell carcinoma. J Cell Biochem 2019; 121:4074-4084. [PMID: 31886566 DOI: 10.1002/jcb.29590] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 12/09/2019] [Indexed: 12/29/2022]
Abstract
Alternative splicing (AS) constitutes a major reason for messenger RNA (mRNA) and protein diversity. Increasing studies have shown a link to splicing dysfunction associated with malignant neoplasia. Systematic analysis of AS events in kidney cancer remains poorly reported. Therefore, we generated AS profiles in 533 kidney renal clear cell carcinoma (KIRC) patients in The Cancer Genome Atlas (TCGA) database using RNA-seq data. Then, prognostic models were developed in a primary cohort (N = 351) and validated in a validation cohort (N = 182). In addition, splicing networks were built by integrating bioinformatics analyses. A total of 11 268 and 8083 AS variants were significantly associated with patient overall survival time in the primary and validation KIRC cohorts, respectively, including STAT1, DAZAP1, IDS, NUDT7, and KLHDC4. The AS events in the primary KIRC cohorts served as candidate AS events to screen the independent risk factors associated with survival in the primary cohort and to develop prognostic models. The area under the curve of the receiver-operator characteristic curve for prognostic prediction in the primary and validation KIRC cohorts was 0.84 and 0.82 at 2500 days of overall survival, respectively. In addition, splicing correlation networks revealed key splicing factors (SFs) in KIRC, such as HNRNPH1, HNRNPU, KHDBS1, KHDBS3, SRSF9, RBMX, SFQ, SRP54, HNRNPA0, and SRSF6. In this study, we analyzed the AS landscape in the TCGA KIRC cohort and detected predictors (prognostic) based on AS variants with high performance for risk stratification of the KIRC cohort and revealed key SFs in splicing networks, which could act as underlying mechanisms.
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Affiliation(s)
- Tao Chen
- Department of Anesthesiology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Wenzhong Zheng
- Department of Anesthesiology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
- Department of Urology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Jianbo Chen
- Department of Surgery, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Shouren Lin
- Department of Reproductive Medicine, Peking University Shenzhen Hospital, Shenzhen, China
| | - Zihao Zou
- Department of Urology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
| | - Xianxin Li
- Department of Surgery, Shenzhen Sun Yat-Sen Cardiovascular Hospital, Shenzhen, China
| | - Zhengling Tan
- Department of Anesthesiology, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, China
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20
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Trivedi J, Alam A, Joshi S, Kumar TP, Chippala V, Mainkar PS, Chandrasekhar S, Chattopadhyay S, Mitra D. A novel isothiocyanate derivative inhibits HIV-1 gene expression and replication by modulating the nuclear matrix associated protein SMAR1. Antiviral Res 2019; 173:104648. [PMID: 31706900 DOI: 10.1016/j.antiviral.2019.104648] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 10/24/2019] [Accepted: 11/04/2019] [Indexed: 12/30/2022]
Abstract
The essential role of SMAR1 in HIV-1 transcription and LTR driven gene expression suggests SMAR1 as an HIV dependency factor (HDF) and a potential anti-HIV therapeutic target. Here, we report for the first time, anti-HIV activity of 8 novel isothiocyanate (ITC) derivatives that differentially stabilise SMAR1. Out of 8 novel ITC derivatives, SCS-OCL-381 was observed to inhibit HIV-1 replication most significantly at the noncytotoxic concentration in reporter T-cell line, CEM-GFP. Further, the highly conserved anti-HIV activity of SCS-OCL-381 is a cell type, virus isolate and viral load independent phenomena and is approximately 3 fold more effective than the representative ITC, Sulforaphane (SFN). Further, SCS-OCL-381 does not hamper the activity of viral enzymes reverse transcriptase, integrase and protease. Mechanistically, SCS-OCL-381 stabilises SMAR1 which, otherwise undergoes proteasomal degradation upon HIV-1 infection in T-cells. This stabilisation results in the recruitment of repressor complex on HIV-1 LTR resulting in repression of LTR mediated transcription and gene expression. These inhibitory consequences were further confirmed by reporter based LTR activity assays in different cell lines. Taken together, these findings highlight the anti-HIV potential of novel ITC derivatives by the stabilisation of SMAR1 and strongly support further in vivo characterisation and potential translational applications of SCS-OCL-381.
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Affiliation(s)
- Jay Trivedi
- National Centre for Cell Science, Pune University Campus, Pune, India.
| | - Aftab Alam
- National Centre for Cell Science, Pune University Campus, Pune, India.
| | - Shruti Joshi
- National Centre for Cell Science, Pune University Campus, Pune, India.
| | | | | | - Prathama S Mainkar
- CSIR-Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India.
| | | | - Samit Chattopadhyay
- National Centre for Cell Science, Pune University Campus, Pune, India; CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India.
| | - Debashis Mitra
- National Centre for Cell Science, Pune University Campus, Pune, India; Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, India.
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21
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The exosome-mediated autocrine and paracrine actions of plasma gelsolin in ovarian cancer chemoresistance. Oncogene 2019; 39:1600-1616. [PMID: 31700155 PMCID: PMC7018662 DOI: 10.1038/s41388-019-1087-9] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 10/22/2019] [Accepted: 10/25/2019] [Indexed: 02/06/2023]
Abstract
Ovarian cancer (OVCA) is the most lethal gynecological cancer, due predominantly to late presentation, high recurrence rate and common chemoresistance development. The expression of the actin-associated protein cytosolic gelsolin (GSN) regulates the gynecological cancer cell fate resulting in dysregulation in chemosensitivity. In this study, we report that elevated expression of plasma gelsolin (pGSN), a secreted isoform of GSN and expressed from the same GSN gene, correlates with poorer overall survival and relapse-free survival in patients with OVCA. In addition, it is highly expressed and secreted in chemoresistant OVCA cells than its chemosensitive counterparts. pGSN, secreted and transported via exosomes (Ex-pGSN), upregulates HIF1α–mediated pGSN expression in chemoresistant OVCA cells in an autocrine manner as well as confers cisplatin resistance in otherwise chemosensitive OVCA cells. These findings support our hypothesis that exosomal pGSN promotes OVCA cell survival through both autocrine and paracrine mechanisms that transform chemosensitive cells to resistant counterparts. Specifically, pGSN transported via exosomes is a determinant of chemoresistance in OVCA.
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22
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Alam A, Taye N, Patel S, Thube M, Mullick J, Shah VK, Pant R, Roychowdhury T, Banerjee N, Chatterjee S, Bhattacharya R, Roy R, Mukhopadhyay A, Mogare D, Chattopadhyay S. SMAR1 favors immunosurveillance of cancer cells by modulating calnexin and MHC I expression. Neoplasia 2019; 21:945-962. [PMID: 31422285 PMCID: PMC6706529 DOI: 10.1016/j.neo.2019.07.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/17/2019] [Indexed: 01/17/2023] Open
Abstract
Down-regulation or loss of MHC class I expression is a major mechanism used by cancer cells to evade immunosurveillance and increase their oncogenic potential. MHC I mediated antigen presentation is a complex regulatory process, controlled by antigen processing machinery (APM) dictating immune response. Transcriptional regulation of the APM that can modulate gene expression profile and their correlation to MHC I mediated antigen presentation in cancer cells remain enigmatic. Here, we reveal that Scaffold/Matrix-Associated Region 1- binding protein (SMAR1), positively regulates MHC I surface expression by down-regulating calnexin, an important component of antigen processing machinery (APM) in cancer cells. SMAR1, a bonafide MAR binding protein acts as a transcriptional repressor of several oncogenes. It is down-regulated in higher grades of cancers either through proteasomal degradation or through loss of heterozygosity (LOH) at the Chr.16q24.3 locus where the human homolog of SMAR1 (BANP) has been mapped. It binds to a short MAR region of the calnexin promoter forming a repressor complex in association with GATA2 and HDAC1. A reverse correlation between SMAR1 and calnexin was thus observed in SMAR1-LOH cells and also in tissues from breast cancer patients. To further extrapolate our findings, influenza A (H1N1) virus infection assay was performed. Upon viral infection, the levels of SMAR1 significantly increased resulting in reduced calnexin expression and increased MHC I presentation. Taken together, our observations establish that increased expression of SMAR1 in cancers can positively regulate MHC I surface expression thereby leading to higher chances of tumor regression and elimination of cancer cells.
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Affiliation(s)
- Aftab Alam
- National Centre for Cell Science, Pune, Maharashtra, India
| | - Nandaraj Taye
- National Centre for Cell Science, Pune, Maharashtra, India
| | - Sonal Patel
- National Centre for Cell Science, Pune, Maharashtra, India
| | - Milind Thube
- ICMR-National Institute of Virology, Pune, Maharashtra, India
| | - Jayati Mullick
- ICMR-National Institute of Virology, Pune, Maharashtra, India
| | | | - Richa Pant
- National Centre for Cell Science, Pune, Maharashtra, India
| | | | | | | | | | - Rini Roy
- Netaji Subhas Chandra Bose Cancer Research Institute, Kolkata, India
| | | | - Devraj Mogare
- National Centre for Cell Science, Pune, Maharashtra, India
| | - Samit Chattopadhyay
- National Centre for Cell Science, Pune, Maharashtra, India; Indian Institute of Chemical Biology, Kolkata, India.
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Siam A, Baker M, Amit L, Regev G, Rabner A, Najar RA, Bentata M, Dahan S, Cohen K, Araten S, Nevo Y, Kay G, Mandel-Gutfreund Y, Salton M. Regulation of alternative splicing by p300-mediated acetylation of splicing factors. RNA (NEW YORK, N.Y.) 2019; 25:813-824. [PMID: 30988101 PMCID: PMC6573785 DOI: 10.1261/rna.069856.118] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 04/08/2019] [Indexed: 05/23/2023]
Abstract
Splicing of precursor mRNA (pre-mRNA) is an important regulatory step in gene expression. Recent evidence points to a regulatory role of chromatin-related proteins in alternative splicing regulation. Using an unbiased approach, we have identified the acetyltransferase p300 as a key chromatin-related regulator of alternative splicing. p300 promotes genome-wide exon inclusion in both a transcription-dependent and -independent manner. Using CD44 as a paradigm, we found that p300 regulates alternative splicing by modulating the binding of splicing factors to pre-mRNA. Using a tethering strategy, we found that binding of p300 to the CD44 promoter region promotes CD44v exon inclusion independently of RNAPII transcriptional elongation rate. Promoter-bound p300 regulates alternative splicing by acetylating splicing factors, leading to exclusion of hnRNP M from CD44 pre-mRNA and activation of Sam68. p300-mediated CD44 alternative splicing reduces cell motility and promotes epithelial features. Our findings reveal a chromatin-related mechanism of alternative splicing regulation and demonstrate its impact on cellular function.
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Affiliation(s)
- Ahmad Siam
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mai Baker
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Leah Amit
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Gal Regev
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Alona Rabner
- Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel
| | - Rauf Ahmad Najar
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Mercedes Bentata
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sara Dahan
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Klil Cohen
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Sarah Araten
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Yuval Nevo
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, 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 91120, Israel
| | | | - Maayan Salton
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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24
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Li YR, Peng RR, Gao WY, Liu P, Chen LJ, Zhang XL, Zhang NN, Wang Y, Du L, Zhu FY, Wang LL, Li CR, Zeng WT, Li JM, Hu F, Zhang D, Yang ZX. The ubiquitin ligase KBTBD8 regulates PKM1 levels via Erk1/2 and Aurora A to ensure oocyte quality. Aging (Albany NY) 2019; 11:1110-1128. [PMID: 30786262 PMCID: PMC6402520 DOI: 10.18632/aging.101802] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 01/24/2019] [Indexed: 12/14/2022]
Abstract
Tight control of energy metabolism is essential for normal cell function and organism survival. PKM (pyruvate kinase, muscle) isoforms 1 and 2 originate from alternative splicing of PKM pre-mRNA. They are key enzymes in oxidative phosphorylation and aerobic glycolysis, respectively, and are essential for ATP generation. The PKM1:PKM2 expression ratio changes with development and differentiation, and may also vary under metabolic stress and other conditions. Until now, there have been no reports about the function and regulation of PKM isozymes in oocytes. Here, we demonstrate that PKM1 or PKM2 depletion significantly disrupts ATP levels and mitochondrial integrity, and exacerbates free-radical generation and apoptosis in mouse oocytes. We also show that KBTBD8, a female fertility factor in the KBTBD ubiquitin ligase family, selectively regulates PKM1 levels through a signaling cascade that includes Erk1/2 and Aurora A kinases as intermediates. Finally, using RNA sequencing and protein network analysis, we identify several regulatory proteins that may be govern generation of mature PKM1 mRNA. These results suggest KBTBD8 affects PKM1 levels in oocytes via a KBTBD8→Erk1/2→Aurora A axis, and may also affect other essential processes involved in maintaining oocyte quality.
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Affiliation(s)
- Yan-Ru Li
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Equal contribution
| | - Rui-Rui Peng
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Equal contribution
| | - Wen-Yi Gao
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Equal contribution
| | - Peng Liu
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Reproductive Medical Center, Huzhou Maternity and Child Health Care Hospital, Huzhou 313000, Zhejiang, P.R. China
- Equal contribution
| | - Liang-Jian Chen
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Equal contribution
| | - Xiao-Lan Zhang
- Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, Jiangsu, P.R. China
- Equal contribution
| | - Na-Na Zhang
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Yang Wang
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Lei Du
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
- Department of Center for Medical Experiments, Third Xiang-Ya Hospital of Central South University, Changsha 410013, Hunan, P.R. China
| | - Feng-Yu Zhu
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Li-Li Wang
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Cong-Rong Li
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Wen-Tao Zeng
- Animal Core Facility, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Jian-Min Li
- Animal Core Facility, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Fan Hu
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Dong Zhang
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
| | - Zhi-Xia Yang
- State Key Lab of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, Jiangsu, P.R. China
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25
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Taye N, Alam A, Ghorai S, Chatterji DG, Parulekar A, Mogare D, Singh S, Sengupta P, Chatterjee S, Bhat MK, Santra MK, Salunkhe PB, Finston SK, Chattopadhyay S. SMAR1 inhibits Wnt/β-catenin signaling and prevents colorectal cancer progression. Oncotarget 2018; 9:21322-21336. [PMID: 29765542 PMCID: PMC5940383 DOI: 10.18632/oncotarget.25093] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 03/21/2018] [Indexed: 12/13/2022] Open
Abstract
Reduced expression of Scaffold/Matrix Attachment Region Binding Protein 1 (SMAR1) is associated with various cancers resulting in poor prognosis of the diseases. However, the precise underlying mechanism elucidating the loss of SMAR1 requires ongoing study. Here, we show that SMAR1 is highly downregulated during aberrant Wnt3a signaling due to proteasomal degradation and predicted poor prognosis of colorectal cancer. However, substitution mutation (Arginine and Lysine to Alanine) in the D-box elements of SMAR1 viz. "RCHL" and "RQRL" completely abrogated its proteasomal degradation despite Wnt3a activity. SMAR1 inhibited Wnt/β-catenin signaling by recruiting Histone deacetylase-5 to β-catenin promoter resulting in reduced cell migration and invasion. Consequently, reduced tumor sizes in in-vivo NOD-SCID mice were observed that strongly associated with suppression of β-catenin. However, loss of SMAR1 led to enriched H3K9 Acetylation in the β-catenin promoter that further increased Wnt/β-catenin signaling activities and enhanced colorectal cancer progression drastically. Using docking and isothermal titration calorimetric studies we show that small microbial peptides viz. AT-01C and AT-01D derived from Mycobacterium tuberculosis mask the D-box elements of SMAR1. These peptides stabilized SMAR1 expression that further inhibited metastatic SW480 colorectal cancer cell migration and invasion. Drastically reduced subcutaneous tumors were observed in in-vivo NOD-SCID mice upon administration of these peptides (25 mg/kg body weight) intraperitoneally. Taken together our structural studies, in-vitro and in-vivo results strongly suggest that the D-box elements of SMAR1 represent novel druggable targets, where the microbial peptides hold promise as novel colorectal cancer therapeutics.
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Affiliation(s)
- Nandaraj Taye
- National Centre for Cell Science, Pune 411 007, India
| | - Aftab Alam
- National Centre for Cell Science, Pune 411 007, India
| | | | | | | | - Devraj Mogare
- National Centre for Cell Science, Pune 411 007, India
| | | | - Pallabi Sengupta
- Department of Biophysics, Bose Institute, Kolkata 700 054, India
| | | | | | | | | | | | - Samit Chattopadhyay
- National Centre for Cell Science, Pune 411 007, India
- Indian Institute of Chemical Biology (CSIR), West Bengal, Kolkata 700 032, India
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26
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Nakka K, Ghigna C, Gabellini D, Dilworth FJ. Diversification of the muscle proteome through alternative splicing. Skelet Muscle 2018; 8:8. [PMID: 29510724 PMCID: PMC5840707 DOI: 10.1186/s13395-018-0152-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/15/2018] [Indexed: 12/16/2022] Open
Abstract
Background Skeletal muscles express a highly specialized proteome that allows the metabolism of energy sources to mediate myofiber contraction. This muscle-specific proteome is partially derived through the muscle-specific transcription of a subset of genes. Surprisingly, RNA sequencing technologies have also revealed a significant role for muscle-specific alternative splicing in generating protein isoforms that give specialized function to the muscle proteome. Main body In this review, we discuss the current knowledge with respect to the mechanisms that allow pre-mRNA transcripts to undergo muscle-specific alternative splicing while identifying some of the key trans-acting splicing factors essential to the process. The importance of specific splicing events to specialized muscle function is presented along with examples in which dysregulated splicing contributes to myopathies. Though there is now an appreciation that alternative splicing is a major contributor to proteome diversification, the emergence of improved “targeted” proteomic methodologies for detection of specific protein isoforms will soon allow us to better appreciate the extent to which alternative splicing modifies the activity of proteins (and their ability to interact with other proteins) in the skeletal muscle. In addition, we highlight a continued need to better explore the signaling pathways that contribute to the temporal control of trans-acting splicing factor activity to ensure specific protein isoforms are expressed in the proper cellular context. Conclusions An understanding of the signal-dependent and signal-independent events driving muscle-specific alternative splicing has the potential to provide us with novel therapeutic strategies to treat different myopathies. Electronic supplementary material The online version of this article (10.1186/s13395-018-0152-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kiran Nakka
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
| | - Claudia Ghigna
- Istituto di Genetica Molecolare-Consiglio Nazionale delle Ricerche (IGM-CNR), Pavia, Italy
| | - Davide Gabellini
- Unit of Gene Expression and Muscular Dystrophy, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, DIBIT2, 5A3-44, via Olgettina 58, 20132, Milan, Italy.
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada. .,Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, 501 Smyth Rd, Mailbox 511, Ottawa, ON, K1H 8L6, Canada.
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27
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Pereira B, Billaud M, Almeida R. RNA-Binding Proteins in Cancer: Old Players and New Actors. Trends Cancer 2017; 3:506-528. [PMID: 28718405 DOI: 10.1016/j.trecan.2017.05.003] [Citation(s) in RCA: 462] [Impact Index Per Article: 66.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/15/2022]
Abstract
RNA-binding proteins (RBPs) are key players in post-transcriptional events. The combination of versatility of their RNA-binding domains with structural flexibility enables RBPs to control the metabolism of a large array of transcripts. Perturbations in RBP-RNA networks activity have been causally associated with cancer development, but the rational framework describing these contributions remains fragmented. We review here the evidence that RBPs modulate multiple cancer traits, emphasize their functional diversity, and assess future trends in the study of RBPs in cancer.
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Affiliation(s)
- Bruno Pereira
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal.
| | - Marc Billaud
- Clinical and Experimental Model of Lymphomagenesis, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1052, Centre National de la Recherche Scientifique (CNRS) Unité 5286, Centre Léon Bérard, Université Claude Bernard Lyon 1, Centre de Recherche en Cancérologie de Lyon, Lyon, France
| | - Raquel Almeida
- i3S - Institute for Research and Innovation in Health, University of Porto, 4200-135 Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-465 Porto, Portugal; Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal; Biology Department, Faculty of Sciences of the University of Porto, 4169-007 Porto, Portugal
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28
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Cdc20 directs proteasome-mediated degradation of the tumor suppressor SMAR1 in higher grades of cancer through the anaphase promoting complex. Cell Death Dis 2017; 8:e2882. [PMID: 28617439 PMCID: PMC5520925 DOI: 10.1038/cddis.2017.270] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 04/25/2017] [Accepted: 05/09/2017] [Indexed: 12/24/2022]
Abstract
The Tumor suppressor SMAR1 (scaffold matrix attachment region binding protein 1) has a crucial role in maintaining genomic stability, cell cycle progression and apoptosis.Our previous finding showed that it is highly suppressed in higher grade of cancer. However, the underlying mechanism of this suppression was not well understood. In this study, we show that SMAR1 expression levels are controlled at the proteasomal level by five RING finger E3 ubiquitin ligases including, Cdc20, a substrate receptor of ubiquitin ligase APC/C complex. We found that Cdc20 binds and promotes proteasomal degradation of SMAR1 in a D-box motif dependent manner. Further, our results demonstrated that Cdc20 promotes proteasomal degradation of SMAR1 through K48-linked specific polyubiquitylation, and that short hairpin RNA mediated inactivation of Cdc20 leads to significant stabilization of SMAR1. These findings suggest that Cdc20 is responsible for maintaining the cellular levels of SMAR1. However, since Cdc20 fails to target SMAR1 upon exposure to genotoxic stresses, SMAR1 helps to maintain genomic stability under these conditions through its DNA damage repair activity. Interestingly, Cdc20-mediated degradation of SMAR1 promotes cell migration and invasion.The reciprocal relationship of the duo is evident in breast cancer cell lines as well as in patient samples, suggesting that Cdc20 functions as an important negative regulator of SMAR1 in higher grades of cancer. Our study reveals for the first time, the molecular mechanism associated with lower levels of expression of the important tumor suppressor SMAR1 in higher grades of breast cancer.
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29
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Zheng K, Jiang Y, He Z, Kitazato K, Wang Y. Cellular defence or viral assist: the dilemma of HDAC6. J Gen Virol 2017; 98:322-337. [PMID: 27959772 DOI: 10.1099/jgv.0.000679] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Histone deacetylase 6 (HDAC6) is a unique cytoplasmic deacetylase that regulates various important biological processes by preventing protein aggregation and deacetylating different non-histone substrates including tubulin, heat shock protein 90, cortactin, retinoic acid inducible gene I and β-catenin. Growing evidence has indicated a dual role for HDAC6 in viral infection and pathogenesis: HDAC6 may represent a host defence mechanism against viral infection by modulating microtubule acetylation, triggering antiviral immune response and stimulating protective autophagy, or it may be hijacked by the virus to enhance proinflammatory response. In this review, we will highlight current data illustrating the complexity and importance of HDAC6 in viral pathogenesis. We will summarize the structure and functional specificity of HDAC6, and its deacetylase- and ubiquitin-dependent activity in key cellular events in response to virus infection. We will also discuss how HDAC6 exerts its direct or indirect histone modification ability in viral lytic-latency switch.
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Affiliation(s)
- Kai Zheng
- Department of Pharmacy, School of Medicine, Shenzhen University, Shenzhen 518060, PR China.,College of Life Science and Technology, Guangzhou Jinan Biomedicine Research and Development Center, Jinan University, Guangzhou 510632, PR China
| | - Yingchun Jiang
- Department of Pharmacy, School of Medicine, Shenzhen University, Shenzhen 518060, PR China
| | - Zhendan He
- Department of Pharmacy, School of Medicine, Shenzhen University, Shenzhen 518060, PR China
| | - Kaio Kitazato
- Division of Molecular Pharmacology of Infectious Agents, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
| | - Yifei Wang
- College of Life Science and Technology, Guangzhou Jinan Biomedicine Research and Development Center, Jinan University, Guangzhou 510632, PR China
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30
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A saga of cancer epigenetics: linking epigenetics to alternative splicing. Biochem J 2017; 474:885-896. [PMID: 28270561 DOI: 10.1042/bcj20161047] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 12/29/2016] [Accepted: 01/05/2017] [Indexed: 12/14/2022]
Abstract
The discovery of an increasing number of alternative splicing events in the human genome highlighted that ∼94% of genes generate alternatively spliced transcripts that may produce different protein isoforms with diverse functions. It is now well known that several diseases are a direct and indirect consequence of aberrant splicing events in humans. In addition to the conventional mode of alternative splicing regulation by 'cis' RNA-binding sites and 'trans' RNA-binding proteins, recent literature provides enormous evidence for epigenetic regulation of alternative splicing. The epigenetic modifications may regulate alternative splicing by either influencing the transcription elongation rate of RNA polymerase II or by recruiting a specific splicing regulator via different chromatin adaptors. The epigenetic alterations and aberrant alternative splicing are known to be associated with various diseases individually, but this review discusses/highlights the latest literature on the role of epigenetic alterations in the regulation of alternative splicing and thereby cancer progression. This review also points out the need for further studies to understand the interplay between epigenetic modifications and aberrant alternative splicing in cancer progression.
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31
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Li Y, Sun N, Lu Z, Sun S, Huang J, Chen Z, He J. Prognostic alternative mRNA splicing signature in non-small cell lung cancer. Cancer Lett 2017; 393:40-51. [PMID: 28223168 DOI: 10.1016/j.canlet.2017.02.016] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/04/2017] [Accepted: 02/12/2017] [Indexed: 12/20/2022]
Abstract
Alternative splicing provides a major mechanism to generate protein diversity. Increasing evidence suggests a link of dysregulation of splicing associated with cancer. Genome-wide alternative splicing profiling in lung cancer remains largely unstudied. We generated alternative splicing profiles in 491 lung adenocarcinoma (LUAD) and 471 lung squamous cell carcinoma (LUSC) patients in TCGA using RNA-seq data, prognostic models and splicing networks were built by integrated bioinformatics analysis. A total of 3691 and 2403 alternative splicing events were significantly associated with patient survival in LUAD and LUSC, respectively, including EGFR, CD44, PIK3C3, RRAS2, MAPKAP1 and FGFR2. The area under the curve of the receiver-operator characteristic curve for prognostic predictor in NSCLC was 0.817 at 2000 days of overall survival which were also over 0.8 in LUAD and LUSC, separately. Interestingly, splicing correlation networks uncovered opposite roles of splicing factors in LUAD and LUSC. We created prognostic predictors based on alternative splicing events with high performances for risk stratification in NSCLC patients and uncovered interesting splicing networks in LUAD and LUSC which could be underlying mechanisms.
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MESH Headings
- Adenocarcinoma/genetics
- Adenocarcinoma/metabolism
- Adenocarcinoma/mortality
- Adenocarcinoma/pathology
- Adenocarcinoma of Lung
- Alternative Splicing
- Area Under Curve
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Carcinoma, Non-Small-Cell Lung/genetics
- Carcinoma, Non-Small-Cell Lung/metabolism
- Carcinoma, Non-Small-Cell Lung/mortality
- Carcinoma, Non-Small-Cell Lung/pathology
- Carcinoma, Squamous Cell/genetics
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/mortality
- Carcinoma, Squamous Cell/pathology
- Computational Biology
- Databases, Genetic
- Gene Expression Profiling/methods
- Gene Expression Regulation, Neoplastic
- Gene Regulatory Networks
- Genome-Wide Association Study
- Humans
- Kaplan-Meier Estimate
- Lung Neoplasms/genetics
- Lung Neoplasms/metabolism
- Lung Neoplasms/mortality
- Lung Neoplasms/pathology
- Prognosis
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- ROC Curve
- Signal Transduction
- Time Factors
- Transcriptome
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Affiliation(s)
- Yuan Li
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Nan Sun
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX, 77030, USA
| | - Zhiliang Lu
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Shouguo Sun
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Jianbing Huang
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Zhaoli Chen
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
| | - Jie He
- Department of Thoracic Surgery, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China.
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32
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Mirlekar B, Gautam D, Chattopadhyay S. Chromatin Remodeling Protein SMAR1 Is a Critical Regulator of T Helper Cell Differentiation and Inflammatory Diseases. Front Immunol 2017; 8:72. [PMID: 28232831 PMCID: PMC5298956 DOI: 10.3389/fimmu.2017.00072] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/17/2017] [Indexed: 12/28/2022] Open
Abstract
T cell differentiation from naïve T cells to specialized effector subsets of mature cells is determined by the iterative action of transcription factors. At each stage of specific T cell lineage differentiation, transcription factor interacts not only with nuclear proteins such as histone and histone modifiers but also with other factors that are bound to the chromatin and play a critical role in gene expression. In this review, we focus on one of such nuclear protein known as tumor suppressor and scaffold matrix attachment region-binding protein 1 (SMAR1) in CD4+ T cell differentiation. SMAR1 facilitates Th1 differentiation by negatively regulating T-bet expression via recruiting HDAC1–SMRT complex to its gene promoter. In contrast, regulatory T (Treg) cell functions are dependent on inhibition of Th17-specific genes mainly IL-17 and STAT3 by SMAR1. Here, we discussed a critical role of chromatin remodeling protein SMAR1 in maintaining a fine-tuned balance between effector CD4+ T cells and Treg cells by influencing the transcription factors during allergic and autoimmune inflammatory diseases.
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Affiliation(s)
- Bhalchandra Mirlekar
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune, India; Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA
| | - Dipendra Gautam
- Lineberger Comprehensive Cancer Center, University of North Carolina , Chapel Hill, NC , USA
| | - Samit Chattopadhyay
- Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Pune, India; Cancer Biology and Inflammatory Disorder Division, Indian Institute of Chemical Biology, Kolkata, India
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33
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Tanimoto A, Takeuchi S, Arai S, Fukuda K, Yamada T, Roca X, Ong ST, Yano S. Histone Deacetylase 3 Inhibition Overcomes BIM Deletion Polymorphism-Mediated Osimertinib Resistance in EGFR-Mutant Lung Cancer. Clin Cancer Res 2016; 23:3139-3149. [PMID: 27986747 DOI: 10.1158/1078-0432.ccr-16-2271] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Revised: 12/02/2016] [Accepted: 12/09/2016] [Indexed: 11/16/2022]
Abstract
Purpose: The BIM deletion polymorphism is associated with apoptosis resistance to EGFR tyrosine kinase inhibitors (EGFR-TKI), such as gefitinib and erlotinib, in non-small cell lung cancer (NSCLC) harboring EGFR mutations. Here, we investigated whether the BIM deletion polymorphism contributes to resistance against osimertinib, a third-generation EGFR-TKI. In addition, we determined the efficacy of a histone deacetylase (HDAC) inhibitor, vorinostat, against this form of resistance and elucidated the underlying mechanism.Experimental Design: We used EGFR-mutated NSCLC cell lines, which were either heterozygous or homozygous for the BIM deletion polymorphism, to evaluate the effect of osimertinib in vitro and in vivo Protein expression was examined by Western blotting. Alternative splicing of BIM mRNA was analyzed by RT-PCR.Results:EGFR-mutated NSCLC cell lines with the BIM deletion polymorphism exhibited apoptosis resistance to osimertinib in a polymorphism dosage-dependent manner, and this resistance was overcome by combined use with vorinostat. Experiments with homozygous BIM deletion-positive cells revealed that vorinostat affected the alternative splicing of BIM mRNA in the deletion allele, increased the expression of active BIM protein, and thereby induced apoptosis in osimertinib-treated cells. These effects were mediated predominantly by HDAC3 inhibition. In xenograft models, combined use of vorinostat with osimertinib could regress tumors in EGFR-mutated NSCLC cells homozygous for the BIM deletion polymorphism. Moreover, this combination could induce apoptosis even when tumor cells acquired EGFR-T790M mutations.Conclusions: These findings indicate the importance of developing HDAC3-selective inhibitors, and their combined use with osimertinib, for treating EGFR-mutated lung cancers carrying the BIM deletion polymorphism. Clin Cancer Res; 23(12); 3139-49. ©2016 AACR.
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Affiliation(s)
- Azusa Tanimoto
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Shinji Takeuchi
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Sachiko Arai
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Koji Fukuda
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Tadaaki Yamada
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan
| | - Xavier Roca
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - S Tiong Ong
- Cancer & Stem Cell Biology Signature Research Programme, Duke-NUS Medical School, Singapore.,Department of Medical Oncology, National Cancer Centre Singapore, Singapore.,Department of Haematology, Singapore General Hospital, Singapore.,Department of Medicine, Duke University Medical Center, Durham, North Carolina
| | - Seiji Yano
- Division of Medical Oncology, Cancer Research Institute, Kanazawa University, Kanazawa, Japan.
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Mathai J, Mittal SPK, Alam A, Ranade P, Mogare D, Patel S, Saxena S, Ghorai S, Kulkarni AP, Chattopadhyay S. SMAR1 binds to T(C/G) repeat and inhibits tumor progression by regulating miR-371-373 cluster. Sci Rep 2016; 6:33779. [PMID: 27671416 PMCID: PMC5037395 DOI: 10.1038/srep33779] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 08/18/2016] [Indexed: 12/19/2022] Open
Abstract
Chromatin architecture and dynamics are regulated by various histone and non-histone proteins. The matrix attachment region binding proteins (MARBPs) play a central role in chromatin organization and function through numerous regulatory proteins. In the present study, we demonstrate that nuclear matrix protein SMAR1 orchestrates global gene regulation as determined by massively parallel ChIP-sequencing. The study revealed that SMAR1 binds to T(C/G) repeat and targets genes involved in diverse biological pathways. We observe that SMAR1 binds and targets distinctly different genes based on the availability of p53. Our data suggest that SMAR1 binds and regulates one of the imperative microRNA clusters in cancer and metastasis, miR-371-373. It negatively regulates miR-371-373 transcription as confirmed by SMAR1 overexpression and knockdown studies. Further, deletion studies indicate that a ~200 bp region in the miR-371-373 promoter is necessary for SMAR1 binding and transcriptional repression. Recruitment of HDAC1/mSin3A complex by SMAR1, concomitant with alteration of histone marks results in downregulation of the miRNA cluster. The regulation of miR-371-373 by SMAR1 inhibits breast cancer tumorigenesis and metastasis as determined by in vivo experiments. Overall, our study highlights the binding of SMAR1 to T(C/G) repeat and its role in cancer through miR-371-373.
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Affiliation(s)
- Jinumary Mathai
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Smriti P K Mittal
- Department of Zoology, Savitribai Phule Pune University Campus, Pune 411007, India
| | - Aftab Alam
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Payal Ranade
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Devraj Mogare
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Sonal Patel
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Smita Saxena
- Bioinformatics Centre, Savitribai Phule Pune University Campus, Pune 411007, India
| | - Suvankar Ghorai
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
| | - Abhijeet P Kulkarni
- Bioinformatics Centre, Savitribai Phule Pune University Campus, Pune 411007, India
| | - Samit Chattopadhyay
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune-411007, India
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Alternative Splicing of Toll-Like Receptor 9 Transcript in Teleost Fish Grouper Is Regulated by NF-κB Signaling via Phosphorylation of the C-Terminal Domain of the RPB1 Subunit of RNA Polymerase II. PLoS One 2016; 11:e0163415. [PMID: 27658294 PMCID: PMC5033454 DOI: 10.1371/journal.pone.0163415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 08/25/2016] [Indexed: 11/19/2022] Open
Abstract
Similar to its mammalian counterparts, teleost Toll-like receptor 9 (TLR9) recognizes unmethylated CpG DNA presented in the genome of bacteria or DNA viruses and initiates signaling pathway(s) for immune responses. We have previously shown that the TLR9 pathway in grouper, an economically important teleost, can be debilitated by an inhibitory gTLR9B isoform, whose production is mediated by RNA alternative splicing. However, how does grouper TLR9 (gTLR9) signaling impinge on the RNA splicing machinery to produce gTlr9B is unknown. Here we show that the gTlr9 alternative splicing is regulated through ligand-induced phosphorylation of the C-terminal domain (CTD) of the largest subunit of RNA polymerase II (Pol II). We first observed that ligand-activated NF- κB pathway biased the production of the gTlr9B isoform. Because NF- κB is known to recruit p-TEFb kinase, which phosphorylates the Pol II CTD at Ser2 residues, we examined p-TEFb’s role in alternative splicing. We found that promoting p-TEFb kinase activity significantly favored the production of the gTlr9B isoform, whereas inhibiting p-TEFb yielded an opposite result. We further showed that p-TEFb-mediated production of the gTlr9B isoform down-regulates its own immune responses, suggesting a self-limiting mechanism. Taken together, our data indicate a feedback mechanism of the gTLR9 signaling pathway to regulate the alternative splicing machinery, which in turn produces an inhibitor to the pathway.
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Shrine N, Tobin MD, Schurmann C, Soler Artigas M, Hui J, Lehtimäki T, Raitakari OT, Pennell CE, Ang QW, Strachan DP, Homuth G, Gläser S, Felix SB, Evans DM, Henderson J, Granell R, Palmer LJ, Huffman J, Hayward C, Scotland G, Malarstig A, Musk B, James AL, Wain LV. Genome-wide association study of copy number variation with lung function identifies a novel signal of association near BANP for forced vital capacity. BMC Genet 2016; 17:116. [PMID: 27514831 PMCID: PMC4981989 DOI: 10.1186/s12863-016-0423-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genome-wide association studies of Single Nucleotide Polymorphisms (SNPs) have identified 55 SNPs associated with lung function. However, little is known about the effect of copy number variants (CNVs) on lung function, although CNVs represent a significant proportion of human genetic polymorphism. To assess the effect of CNVs on lung function quantitative traits, we measured copy number at 2788 previously characterised, common copy number variable regions in 6 independent cohorts (n = 24,237) using intensity data from SNP genotyping experiments. We developed a pipeline for genome-wide association analysis and meta-analysis of CNV genotypes measured across multiple studies using SNP genotype array intensity data from different platform technologies. We then undertook cohort-level genome-wide association studies of CNV with lung function in a subset of 4 cohorts (n < =12,403) with lung function measurements and meta-analysed the results. Follow-up was undertaken for CNVs which were well tagged by SNPs, in up to 146,871 individuals. RESULTS We generated robust copy number calls for 1962 out of 2788 (70 %) known CNV regions genome-wide, with 1103 measured with compatible class frequencies in at least 2 cohorts. We report a novel CNV association (discovery P = 0.0007) with Forced Vital Capacity (FVC) downstream of BANP on chromosome 16 that shows evidence of replication by a tag SNP in two independent studies (replication P = 0.004). In addition, we provide suggestive evidence (discovery P = 0.0002) for a role of complex copy number variation at a previously reported lung function locus, containing the rootletin gene CROCC, that is not tagged by SNPs. CONCLUSIONS We demonstrate how common CNV regions can be reliably and consistently called across cohorts, using an existing calling algorithm and rigorous quality control steps, using SNP genotyping array intensity data. Although many common biallelic CNV regions were well-tagged by common SNPs, we also identified associations with untagged mulitallelic CNV regions thereby illustrating the potential of our approach to identify some of the missing heritability of complex traits.
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Affiliation(s)
- Nick Shrine
- Department of Health Sciences, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Martin D. Tobin
- Department of Health Sciences, University of Leicester, University Road, Leicester, LE1 7RH UK
- National Institute for Health Research (NIHR) Leicester Respiratory Biomedical Research Unit, Glenfield Hospital, Leicester, LE3 9QP UK
| | - Claudia Schurmann
- Department of Functional Genomics, University Medicine Greifswald, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
- DZHK (German Center for Cardiovascular Research), partner site Greifswald, 17475 Greifswald, Germany
| | - María Soler Artigas
- Department of Health Sciences, University of Leicester, University Road, Leicester, LE1 7RH UK
| | - Jennie Hui
- Busselton Population Medical Research Institute, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Terho Lehtimäki
- Department of Clinical Chemistry, Fimlab Laboratories, University of Tampere and Tampere University Hospital, Tampere, 33521 Finland
| | - Olli T. Raitakari
- Department of Clinical Physiology, Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku University Hospital, Turku, 20521 Finland
| | - Craig E. Pennell
- School of Women’s and Infants’ Health, The University of Western Australia, Perth, Australia
| | - Qi Wei Ang
- School of Women’s and Infants’ Health, The University of Western Australia, Perth, Australia
| | - David P. Strachan
- Division of Population Health Sciences, St. George’s University of London, London, UK
| | - Georg Homuth
- Department of Functional Genomics, University Medicine Greifswald, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
| | - Sven Gläser
- Department of Internal Medicine B – Pulmonary Medicine, Weaning and Infectious Diseases and Scientific Division of Pneumology and Pneumological Epidemiology, University Medicine Greifswald, Greifswald, Germany
| | - Stephan B. Felix
- Department of Functional Genomics, University Medicine Greifswald, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
- Department of Internal Medicine B – Cardiology, University Medicine Greifswald, Greifswald, Germany
| | - David M. Evans
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- School of Social and Community Medicine, University of Bristol, Bristol, UK
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Queensland Australia
| | - John Henderson
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Raquel Granell
- School of Social and Community Medicine, University of Bristol, Bristol, UK
| | - Lyle J. Palmer
- School of Public Health, University of Adelaide, Adelaide, Australia
| | - Jennifer Huffman
- Institute of Genetics and Molecular Medicine, University of Edinburgh Western General Hospital, Crewe Road, Edinburgh, EH4 2XU UK
| | - Caroline Hayward
- Institute of Genetics and Molecular Medicine, University of Edinburgh Western General Hospital, Crewe Road, Edinburgh, EH4 2XU UK
| | - Generation Scotland
- Institute of Genetics and Molecular Medicine, University of Edinburgh Western General Hospital, Crewe Road, Edinburgh, EH4 2XU UK
| | | | - Bill Musk
- Busselton Population Medical Research Institute, Sir Charles Gairdner Hospital, Nedlands, Australia
- Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Alan L. James
- Busselton Population Medical Research Institute, Sir Charles Gairdner Hospital, Nedlands, Australia
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - UK BiLEVE
- Department of Health Sciences, University of Leicester, University Road, Leicester, LE1 7RH UK
- National Institute for Health Research (NIHR) Leicester Respiratory Biomedical Research Unit, Glenfield Hospital, Leicester, LE3 9QP UK
- Department of Functional Genomics, University Medicine Greifswald, Interfaculty Institute for Genetics and Functional Genomics, Greifswald, Germany
- DZHK (German Center for Cardiovascular Research), partner site Greifswald, 17475 Greifswald, Germany
- Busselton Population Medical Research Institute, Sir Charles Gairdner Hospital, Nedlands, Australia
- Department of Clinical Chemistry, Fimlab Laboratories, University of Tampere and Tampere University Hospital, Tampere, 33521 Finland
- Department of Clinical Physiology, Research Centre of Applied and Preventive Cardiovascular Medicine, University of Turku, Turku University Hospital, Turku, 20521 Finland
- School of Women’s and Infants’ Health, The University of Western Australia, Perth, Australia
- Division of Population Health Sciences, St. George’s University of London, London, UK
- Department of Internal Medicine B – Pulmonary Medicine, Weaning and Infectious Diseases and Scientific Division of Pneumology and Pneumological Epidemiology, University Medicine Greifswald, Greifswald, Germany
- Department of Internal Medicine B – Cardiology, University Medicine Greifswald, Greifswald, Germany
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- School of Social and Community Medicine, University of Bristol, Bristol, UK
- University of Queensland Diamantina Institute, Translational Research Institute, Brisbane, Queensland Australia
- School of Public Health, University of Adelaide, Adelaide, Australia
- Institute of Genetics and Molecular Medicine, University of Edinburgh Western General Hospital, Crewe Road, Edinburgh, EH4 2XU UK
- Pfizer Worldwide Research and Development, Sollentuna, Sweden
- Department of Respiratory Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia
- Department of Pulmonary Physiology and Sleep Medicine, Sir Charles Gairdner Hospital, Nedlands, Australia
| | - Louise V. Wain
- Department of Health Sciences, University of Leicester, University Road, Leicester, LE1 7RH UK
- National Institute for Health Research (NIHR) Leicester Respiratory Biomedical Research Unit, Glenfield Hospital, Leicester, LE3 9QP UK
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Rai DK, Lawrence P, Kloc A, Schafer E, Rieder E. Analysis of the interaction between host factor Sam68 and viral elements during foot-and-mouth disease virus infections. Virol J 2015; 12:224. [PMID: 26695943 PMCID: PMC4689063 DOI: 10.1186/s12985-015-0452-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 12/10/2015] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The nuclear protein Src-associated protein of 68 kDa in mitosis (Sam68) is known to bind RNA and be involved in cellular processes triggered in response to environmental stresses, including virus infection. Interestingly, Sam68 is a multi-functional protein implicated in the life cycle of retroviruses and picornaviruses and is also considered a marker of virus-induced stress granules (SGs). Recently, we demonstrated the partial redistribution of Sam68 to the cytoplasm in FMDV infected cells, its interaction with viral protease 3C(pro), and found a significant reduction in viral titers as consequence of Sam68-specific siRNA knockdowns. Despite of that, details of how it benefits FMDV remains to be elucidated. METHODS Sam68 cytoplasmic localization was examined by immunofluorescent microscopy, counterstaining with antibodies against Sam68, a viral capsid protein and markers of SGs. The relevance of RAAA motifs in the IRES was investigated using electromobility shift assays with Sam68 protein and parental and mutant FMDV RNAs. In addition, full genome WT and mutant or G-luc replicon RNAs were tested following transfection in mammalian cells. The impact of Sam68 depletion to virus protein and RNA synthesis was investigated in a cell-free system. Lastly, through co-immunoprecipitation, structural modeling, and subcellular fractionation, viral protein interactions with Sam68 were explored. RESULTS FMDV-induced cytoplasmic redistribution of Sam68 resulted in it temporarily co-localizing with SG marker: TIA-1. Mutations that disrupted FMDV IRES RAAA motifs, with putative affinity to Sam68 in domain 3 and 4 cause a reduction on the formation of ribonucleoprotein complexes with this protein and resulted in non-viable progeny viruses and replication-impaired replicons. Furthermore, depletion of Sam68 in cell-free extracts greatly diminished FMDV RNA replication, which was restored by addition of recombinant Sam68. The results here demonstrated that Sam68 specifically co-precipitates with both FMDV 3D(pol) and 3C(pro) consistent with early observations of FMDV 3C(pro)-induced cleavage of Sam68. CONCLUSION We have found that Sam68 is a specific binding partner for FMDV non-structural proteins 3C(pro) and 3D(pol) and showed that mutations at RAAA motifs in IRES domains 3 and 4 cause a decrease in Sam68 affinity to these RNA elements and rendered the mutant RNA non-viable. Interestingly, in FMDV infected cells re-localized Sam68 was transiently detected along with SG markers in the cytoplasm. These results support the importance of Sam68 as a host factor co-opted by FMDV during infection and demonstrate that Sam68 interact with both, FMDV RNA motifs in the IRES and viral non-structural proteins 3C(pro) and 3D(pol).
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Affiliation(s)
- Devendra K Rai
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Paul Lawrence
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Anna Kloc
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Elizabeth Schafer
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
| | - Elizabeth Rieder
- Foreign Animal Disease Research Unit, United States Department of Agriculture, Agricultural Research Service, Plum Island Animal Disease Center, USDA/ARS/NAA, P.O. Box 848, Greenport, NY, 11944, USA.
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Shkreta L, Chabot B. The RNA Splicing Response to DNA Damage. Biomolecules 2015; 5:2935-77. [PMID: 26529031 PMCID: PMC4693264 DOI: 10.3390/biom5042935] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 09/20/2015] [Accepted: 10/16/2015] [Indexed: 12/29/2022] Open
Abstract
The number of factors known to participate in the DNA damage response (DDR) has expanded considerably in recent years to include splicing and alternative splicing factors. While the binding of splicing proteins and ribonucleoprotein complexes to nascent transcripts prevents genomic instability by deterring the formation of RNA/DNA duplexes, splicing factors are also recruited to, or removed from, sites of DNA damage. The first steps of the DDR promote the post-translational modification of splicing factors to affect their localization and activity, while more downstream DDR events alter their expression. Although descriptions of molecular mechanisms remain limited, an emerging trend is that DNA damage disrupts the coupling of constitutive and alternative splicing with the transcription of genes involved in DNA repair, cell-cycle control and apoptosis. A better understanding of how changes in splice site selection are integrated into the DDR may provide new avenues to combat cancer and delay aging.
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Affiliation(s)
- Lulzim Shkreta
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
| | - Benoit Chabot
- Microbiologie et d'Infectiologie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada.
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