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Shin SY, Centenera MM, Hodgson JT, Nguyen EV, Butler LM, Daly RJ, Nguyen LK. A Boolean-based machine learning framework identifies predictive biomarkers of HSP90-targeted therapy response in prostate cancer. Front Mol Biosci 2023; 10:1094321. [PMID: 36743211 PMCID: PMC9892654 DOI: 10.3389/fmolb.2023.1094321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/06/2023] [Indexed: 01/20/2023] Open
Abstract
Precision medicine has emerged as an important paradigm in oncology, driven by the significant heterogeneity of individual patients' tumour. A key prerequisite for effective implementation of precision oncology is the development of companion biomarkers that can predict response to anti-cancer therapies and guide patient selection for clinical trials and/or treatment. However, reliable predictive biomarkers are currently lacking for many anti-cancer therapies, hampering their clinical application. Here, we developed a novel machine learning-based framework to derive predictive multi-gene biomarker panels and associated expression signatures that accurately predict cancer drug sensitivity. We demonstrated the power of the approach by applying it to identify response biomarker panels for an Hsp90-based therapy in prostate cancer, using proteomic data profiled from prostate cancer patient-derived explants. Our approach employs a rational feature section strategy to maximise model performance, and innovatively utilizes Boolean algebra methods to derive specific expression signatures of the marker proteins. Given suitable data for model training, the approach is also applicable to other cancer drug agents in different tumour settings.
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Affiliation(s)
- Sung-Young Shin
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia,Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia,*Correspondence: Sung-Young Shin, ; Lan K. Nguyen,
| | - Margaret M. Centenera
- South Australian Immunogenomics Cancer Institute and Freemasons Foundation Centre for Men’s Health, University of Adelaide, Adelaide, SA, Australia,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Joshua T. Hodgson
- South Australian Immunogenomics Cancer Institute and Freemasons Foundation Centre for Men’s Health, University of Adelaide, Adelaide, SA, Australia,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Elizabeth V. Nguyen
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia,Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Lisa M. Butler
- South Australian Immunogenomics Cancer Institute and Freemasons Foundation Centre for Men’s Health, University of Adelaide, Adelaide, SA, Australia,South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Roger J. Daly
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia,Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Lan K. Nguyen
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia,Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia,*Correspondence: Sung-Young Shin, ; Lan K. Nguyen,
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2
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Wang X, Chen D, Han G, Wang X, Liu X, Xu B, Liu W, Li H, Zhang M, Ma S, Han Y. Downregulation of RBM17 enhances cisplatin sensitivity and inhibits cell invasion in human hypopharyngeal cancer cells. Open Med (Wars) 2023; 18:20230669. [PMID: 36941989 PMCID: PMC10024346 DOI: 10.1515/med-2023-0669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 03/17/2023] Open
Abstract
Most of advanced hypopharyngeal squamous cell carcinoma (HSCC) are resistant to chemotherapy, and there is still lack of effective treatment for HSCC now. The present study aimed to investigate whether downregulation of RNA-binding motif protein 17 (RBM17) could enhance cisplatin sensitivity and inhibit cell invasion in HSCC and the underlying mechanism. We observed that RBM17 was upregulated in tumor tissues and associated with poor progression. Treatment of FaDu cells with cisplatin increased RBM17 expression in mRNA levels. Downregulation of RBM17 enhanced cisplatin-mediated inhibition of FaDu cells. In addition, downregulation of RBM17 effectively suppressed tumor cell migration and invasion through the reversion of epithelial-mesenchymal transition. Moreover, downregulation of RBM17 could significantly slow tumor growth in FaDu xenograft tumor model. Liquid chromatography-mass spectrometry/mass spectrometry detection and independent PRM analysis showed that 21 differentially expressed proteins were associated with the downregulation of RBM17. Taken together, our study implied that downregulation of RBM17 could serve as a novel approach to enhance cisplatin sensitivity in HSCC.
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Affiliation(s)
- Xiaolin Wang
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Deshang Chen
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Guoying Han
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Xiaomin Wang
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Xuebao Liu
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Binbin Xu
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Weiwei Liu
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Hui Li
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Mingjie Zhang
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Shiyin Ma
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, China
| | - Yuefeng Han
- Department Of Otolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, 287 Changhuai Road, Bengbu, Anhui 233000, China
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3
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Fu Y, Bai C, Wang S, Chen D, Zhang P, Wei H, Rong F, Zhang C, Chen S, Wang Z. AKT1 phosphorylates RBM17 to promote Sox2 transcription by modulating alternative splicing of FOXM1 to enhance cancer stem cell properties in colorectal cancer cells. FASEB J 2023; 37:e22707. [PMID: 36520054 DOI: 10.1096/fj.202201255r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 11/15/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022]
Abstract
Colorectal cancer (CRC) is one of the leading causes of cancer-related death worldwide. The existence of cancer stem cells (CSC) causes tumor relapses, metastasis, and resistance to conventional therapy. Alternative splicing has been shown to affect physiological and pathological processes. Accumulating evidence has confirmed that targeting alternative splicing could be an effective strategy to treat CRC. Currently, the role of alternative splicing in the regulation of CSC properties in CRC has not been elucidated. Here, we show that RBM17 displays oncogenic roles in CRC cells. RBM17 enhances cell proliferation and reduces chemotherapeutic-induced apoptosis in CRC cells. Besides, RBM17 increases CD133 positive and ALDEFLUOR positive populations and promotes sphere formation in CRC cells. In mechanism studies, we found that FOXM1 is critical for RBM17 enhanced CSC properties. Moreover, FOXM1 alternative splicing is essential for RBM17 enhanced CSC properties in CRC cells. Additionally, RBM17 enhances CSC characteristics by controlling FOXM1 expression to promote Sox2 expression. Furthermore, AKT1 works as an upstream kinase to control RBM17-mediated FOXM1 alternative splicing and enhancement of CSC properties in CRC cells. Our study reveals that AKT1-RBM17-FOXM1-Sox2 axis could be a potential target for modulating alternative splicing to reduce CSC properties in CRC cells.
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Affiliation(s)
- Yan Fu
- Department of General Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People's Republic of China.,Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, China.,Center for Evidence Based Medicine and Clinical Research, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Chen Bai
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Shengsheng Wang
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Denggang Chen
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Peng Zhang
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Hailang Wei
- Department of General Surgery, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Fan Rong
- Hubei Key Laboratory of Embryonic Stem Cell Research, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Chao Zhang
- Center for Evidence Based Medicine and Clinical Research, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Shaojuan Chen
- Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, China
| | - Zhenjun Wang
- Department of General Surgery, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, People's Republic of China
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4
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Liu L, Vujovic A, Deshpande NP, Sathe S, Anande G, Chen HTT, Xu J, Minden MD, Yeo GW, Unnikrishnan A, Hope KJ, Lu Y. The splicing factor RBM17 drives leukemic stem cell maintenance by evading nonsense-mediated decay of pro-leukemic factors. Nat Commun 2022; 13:3833. [PMID: 35781533 PMCID: PMC9250932 DOI: 10.1038/s41467-022-31155-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Accepted: 05/30/2022] [Indexed: 12/01/2022] Open
Abstract
Chemo-resistance in acute myeloid leukemia (AML) patients is driven by leukemic stem cells (LSCs) resulting in high rates of relapse and low overall survival. Here, we demonstrate that upregulation of the splicing factor, RBM17 preferentially marks and sustains LSCs and directly correlates with shorten patient survival. RBM17 knockdown in primary AML cells leads to myeloid differentiation and impaired colony formation and in vivo engraftment. Integrative multi-omics analyses show that RBM17 repression leads to inclusion of poison exons and production of nonsense-mediated decay (NMD)-sensitive transcripts for pro-leukemic factors and the translation initiation factor, EIF4A2. We show that EIF4A2 is enriched in LSCs and its inhibition impairs primary AML progenitor activity. Proteomic analysis of EIF4A2-depleted AML cells shows recapitulation of the RBM17 knockdown biological effects, including pronounced suppression of proteins involved in ribosome biogenesis. Overall, these results provide a rationale to target RBM17 and/or its downstream NMD-sensitive splicing substrates for AML treatment.
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Affiliation(s)
- Lina Liu
- Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Ana Vujovic
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Nandan P Deshpande
- Adult Cancer Program, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
- Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Shashank Sathe
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California at San Diego, San Diego, CA, USA
| | - Govardhan Anande
- Adult Cancer Program, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
- Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - He Tian Tony Chen
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Joshua Xu
- Department of Biochemistry and Biomedical Sciences, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Mark D Minden
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, Stem Cell Program and Institute for Genomic Medicine, University of California at San Diego, San Diego, CA, USA
| | - Ashwin Unnikrishnan
- Adult Cancer Program, Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW, Australia
- Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, Australia
| | - Kristin J Hope
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada.
| | - Yu Lu
- Department of Medicine, Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada.
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5
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Martín E, Vivori C, Rogalska M, Herrero-Vicente J, Valcárcel J. Alternative splicing regulation of cell-cycle genes by SPF45/SR140/CHERP complex controls cell proliferation. RNA (NEW YORK, N.Y.) 2021; 27:1557-1576. [PMID: 34544891 PMCID: PMC8594467 DOI: 10.1261/rna.078935.121] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 09/11/2021] [Indexed: 06/10/2023]
Abstract
The regulation of pre-mRNA processing has important consequences for cell division and the control of cancer cell proliferation, but the underlying molecular mechanisms remain poorly understood. We report that three splicing factors, SPF45, SR140, and CHERP, form a tight physical and functionally coherent complex that regulates a variety of alternative splicing events, frequently by repressing short exons flanked by suboptimal 3' splice sites. These comprise alternative exons embedded in genes with important functions in cell-cycle progression, including the G2/M key regulator FOXM1 and the spindle regulator SPDL1. Knockdown of either of the three factors leads to G2/M arrest and to enhanced apoptosis in HeLa cells. Promoting the changes in FOXM1 or SPDL1 splicing induced by SPF45/SR140/CHERP knockdown partially recapitulates the effects on cell growth, arguing that the complex orchestrates a program of alternative splicing necessary for efficient cell proliferation.
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Affiliation(s)
- Elena Martín
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
| | - Claudia Vivori
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
| | - Malgorzata Rogalska
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
| | - Jorge Herrero-Vicente
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
| | - Juan Valcárcel
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona 08003, Spain
- Universitat Pompeu Fabra (UPF), Barcelona 08003, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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6
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Fukumura K, Venables JP, Mayeda A. SPF45/RBM17-dependent splicing and multidrug resistance to cancer chemotherapy. Mol Cell Oncol 2021; 8:1996318. [PMID: 35419480 PMCID: PMC8997263 DOI: 10.1080/23723556.2021.1996318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/10/2021] [Accepted: 10/13/2021] [Indexed: 06/14/2023]
Abstract
The early splicing complex A occupies at least eighty nucleotides of intron, in which U2AF covers the polypyrimidine tract. SPF45 (RBM17) functionally substitutes for U2AF on a subset of short introns. Since SPF45 expression confers resistance to various anticancer drugs, SPF45-dependent splicing may play a critical role in multidrug resistance.
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Affiliation(s)
- Kazuhiro Fukumura
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Julian P. Venables
- Science Sense, 2 Rue St Vincent, Salèlles du Bosc, 34700 Le Bosc, France
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
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7
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Kochanek SJ, Close DA, Wang AX, Shun T, Empey PE, Eiseman JL, Johnston PA. Confirmation of Selected Synergistic Cancer Drug Combinations Identified in an HTS Campaign and Exploration of Drug Efflux Transporter Contributions to the Mode of Synergy. SLAS DISCOVERY 2019; 24:653-668. [PMID: 31039321 DOI: 10.1177/2472555219844566] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Systematic unbiased high-throughput screening (HTS) of drug combinations (DCs) in well-characterized tumor cell lines is a data-driven strategy to identify novel DCs with potential to be developed into effective therapies. Four DCs from a DC HTS campaign were selected for confirmation; only one appears in clinicaltrials.gov and limited preclinical in vitro data indicates that the drug pairs interact synergistically. Nineteen DC-tumor cell line sets were confirmed to interact synergistically in three pharmacological interaction models. We developed an imaging assay to quantify accumulation of the ABCG2 efflux transporter substrate Hoechst. Gefitinib and raloxifene enhanced Hoechst accumulation in ABCG2 (BCRP)-expressing cells, consistent with inhibition of ABCG2 efflux. Both drugs also inhibit ABCB1 efflux. Mitoxantrone, daunorubicin, and vinorelbine are substrates of one or more of the ABCG2, ABCB1, or ABCC1 efflux transporters expressed to varying extents in the selected cell lines. Interactions between ABC drug efflux transporter inhibitors and substrates may have contributed to the observed synergy; however, other mechanisms may be involved. Novel synergistic DCs identified by HTS were confirmed in vitro, and plausible mechanisms of action studied. Similar approaches may justify the testing of novel HTS-derived DCs in mouse xenograft human cancer models and support the clinical evaluation of effective in vivo DCs in patients.
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Affiliation(s)
- Stanton J Kochanek
- 1 Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA
| | - David A Close
- 1 Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA
| | - Allen Xinwei Wang
- 1 Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA
| | - Tongying Shun
- 2 University of Pittsburgh Drug Discovery Institute, Pittsburgh, PA, USA
| | - Philip E Empey
- 3 Department of Pharmacy and Therapeutics, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA
| | - Julie L Eiseman
- 4 University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA, USA.,5 Cancer Therapeutics Program, The University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA, USA.,6 Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Paul A Johnston
- 1 Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA, USA.,4 University of Pittsburgh Hillman Cancer Center, Pittsburgh, PA, USA
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8
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Zhou Z, Chen Y, Jin M, He J, Guli A, Yan C, Ding S. Comprehensive Analysis of Lysine Acetylome Reveals a Site-Specific Pattern in Rapamycin-Induced Autophagy. J Proteome Res 2019; 18:865-877. [PMID: 30592415 DOI: 10.1021/acs.jproteome.8b00533] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Protein acetylation reportedly acts as a key regulator of autophagy. However, up to now, the relationship between acetylome and autophagy has remained unclear. Here stable isotope labeling of amino acids in cell culture and high-throughput quantitative mass spectrometry were used to perform an acetylome analysis of rapamycin-induced autophagy in vitro. Our data revealed that 2135 sites were quantified on 1081 proteins. During autophagy, 421 sites were significantly regulated on 296 proteins, with 80.8% of sites downregulated and 19.2% upregulated. Motif enrichment analysis revealed five main motifs. Most of the downregulated sites conformed to the classical functional motif of p300/CBP [G-AcK]. Furthermore, acetylation targeted proteins involved mainly in ribosomes, spliceosomes, and AcCoA-related metabolic process. In-depth analysis indicated that most of the acetylation sites were in the critical domain, were functional sites, or could change their enzymatic activity by acetylation, highlighting the importance of site-specific acetylation patterns. Subsequently, we demonstrated that K1549 of p300 was also a functional site that could regulate the autophagic process in vitro. In conclusion, our data reveal a deacetylation-preponderant profile with autophagy. The specificity of the related motifs and the identification of site-specific acetylation patterns will assist searches for potential targets or subsequent mechanism-focused studies to elucidate site-specific protein networks in autophagy.
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Affiliation(s)
- Zhuo Zhou
- The National Education Base for Basic Medical Sciences , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
| | - Yu Chen
- The National Education Base for Basic Medical Sciences , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
| | - Mengqi Jin
- The National Education Base for Basic Medical Sciences , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
| | - Jianqin He
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital , Zhejiang University School of Medicine , 79 Qingchun Road , Hangzhou 310003 , Zhejiang Province , China
| | - Ayiding Guli
- The National Education Base for Basic Medical Sciences , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
| | - Chunlan Yan
- Department of Biophysics, Key Laboratory of Medical Neurobiology, Ministry of Health of China , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
| | - Shiping Ding
- The National Education Base for Basic Medical Sciences , Zhejiang University School of Medicine , 866 Yuhangtang Road , Hangzhou 310058 , Zhejiang Province , China
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9
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Lu J, Li Q, Cai L, Zhu Z, Guan J, Wang C, Xia J, Xia L, Wen M, Zheng W, Su Z, Wang C. RBM17 controls apoptosis and proliferation to promote Glioma progression. Biochem Biophys Res Commun 2018; 505:20-28. [PMID: 30227940 DOI: 10.1016/j.bbrc.2018.09.056] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Accepted: 09/09/2018] [Indexed: 01/13/2023]
Abstract
The splicing factor SPF45 (RBM17) is a well-known component of the spliceosome that is involved in alternative splicing. RBM17 is frequently overexpressed in many tumors and plays a crucial role in cancer progression and drug resistance. However, the role of RBM17 in the development of glioma has not been thoroughly elucidated to date. In the present study, we found that RBM17 was overexpressed in glioma and that a high level of expression of RBM17 was closely associated with a poor prognosis in glioma patients. We investigated the effect of RBM17 on apoptosis, cell growth and cell cycle indexes and the activation of apoptosis signaling by shRNA in human U87 and U251 glioma cells. The downregulated expression of RBM17 mRNA was accompanied by the induction of cell cycle arrest, and apoptosis, reduced cell proliferation in the two cell lines, and reduced cell survival, as measured by the increased activation of caspase-3, caspase-9, and PARP (poly ADP-ribose polymerase). Furthermore, in subcutaneous U87 cell xenograft tumors in nude mice, intradermal administration of an shRNA targeting RBM17 significantly downregulated RBM17 expression in vivo and was accompanied by the suppressed growth of glioma. To the best of our knowledge, our results are the first to confirm that RBM17 functions in promoting cell proliferation, affecting the cell cycle, and inducing apoptosis in human glioma cells both in vitro and in vivo. These results indicate that RBM17 may be a therapeutic target in the clinical management of glioma.
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Affiliation(s)
- Jianglong Lu
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Qun Li
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Lin Cai
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Zhangzhang Zhu
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Jiaqing Guan
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Chunyong Wang
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Jia Xia
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Lei Xia
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Min Wen
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Weiming Zheng
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China
| | - Zhipeng Su
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China.
| | - Chengde Wang
- Department of Neurosurgery, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China.
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10
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Han Y, Zhang M, Chen D, Li H, Wang X, Ma S. Downregulation of RNA binding motif protein 17 expression inhibits proliferation of hypopharyngeal carcinoma FaDu cells. Oncol Lett 2018; 15:5680-5684. [PMID: 29552202 PMCID: PMC5840662 DOI: 10.3892/ol.2018.8012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 12/12/2017] [Indexed: 12/13/2022] Open
Abstract
RNA binding motif protein 17 (RBM17) is a protein-coding gene. The protein encoded by RBM17 is involved in the regulation of alternative splicing and is overexpressed in cancer. The present study aimed to determine the effect of RBM17-knockdown in hypopharyngeal carcinoma FaDu cells using the lentivirus-mediated shRNA method. Cell proliferation was detected by an MTT assay. Flow cytometry analysis was used to determine cell cycle distribution and apoptosis. The results of the present study demonstrated that RBM17 expression was significantly decreased in FaDu cells infected with lentivirus-shRNA. Knockdown of RBM17 expression by shRNA significantly reduced cell proliferation, augmented cell apoptosis and arrested cells at the G2/M phase in FaDu cells. The results of the present study indicate that RBM17 serves a notable role in cell proliferation, cell cycle progression and apoptosis of hypopharyngeal carcinoma cells.
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Affiliation(s)
- Yuefeng Han
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
| | - Mingjie Zhang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
| | - Deshang Chen
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
| | - Hui Li
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
| | - Xiaomin Wang
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
| | - Shiyin Ma
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui 233000, P.R. China
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11
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Taketo K, Konno M, Asai A, Koseki J, Toratani M, Satoh T, Doki Y, Mori M, Ishii H, Ogawa K. The epitranscriptome m6A writer METTL3 promotes chemo- and radioresistance in pancreatic cancer cells. Int J Oncol 2017; 52:621-629. [PMID: 29345285 DOI: 10.3892/ijo.2017.4219] [Citation(s) in RCA: 180] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 10/16/2017] [Indexed: 11/06/2022] Open
Abstract
N6-methyladenosine (m6A) is the most abundant epitranscriptome modification in mammalian mRNA. Recent years have seen substantial progress in m6A epitranscriptomics, indicating its crucial roles in the initiation and progression of cancer through regulation of RNA stabilities, mRNA splicing, microRNA processing and mRNA translation. However, by what means m6A is dynamically regulated or written by enzymatic components represented by methyltransferase-like 3 (METTL3) and how m6A is significant for each of the numerous genes remain unclear. We focused on METTL3 in pancreatic cancer, the prognosis of which is not satisfactory despite the development of multidisciplinary therapies. We established METTL3-knockdown pancreatic cancer cell line using short hairpin RNA. Although morphologic and proliferative changes were unaffected, METTL3-depleted cells showed higher sensitivity to anticancer reagents such as gemcitabine, 5-fluorouracil, cisplatin and irradiation. Our data suggest that METTL3 is a potent target for enhancing therapeutic efficacy in patients with pancreatic cancer. In addition, we performed cDNA expression analysis followed by gene ontology and protein-protein interaction analysis using the Database for Annotation, Visualization, and Integrated Discovery and Search Tool for the Retrieval of Interacting Genes/Proteins databases, respectively. The results demonstrate that METTL3 was associated with mitogen-activated protein kinase cascades, ubiquitin-dependent process and RNA splicing and regulation of cellular process, suggesting functional roles and targets of METTL3.
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Affiliation(s)
- Kosuke Taketo
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masamitsu Konno
- Department of Medical Data Science, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Ayumu Asai
- Department of Medical Data Science, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Jun Koseki
- Department of Medical Data Science, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masayasu Toratani
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Taroh Satoh
- Department of Cancer Frontier Science, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Yuichiro Doki
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Masaki Mori
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Hideshi Ishii
- Department of Medical Data Science, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Kazuhiko Ogawa
- Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
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12
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Tan Q, Yalamanchili HK, Park J, De Maio A, Lu HC, Wan YW, White JJ, Bondar VV, Sayegh LS, Liu X, Gao Y, Sillitoe RV, Orr HT, Liu Z, Zoghbi HY. Extensive cryptic splicing upon loss of RBM17 and TDP43 in neurodegeneration models. Hum Mol Genet 2017; 25:5083-5093. [PMID: 28007900 DOI: 10.1093/hmg/ddw337] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 09/29/2016] [Indexed: 12/12/2022] Open
Abstract
Splicing regulation is an important step of post-transcriptional gene regulation. It is a highly dynamic process orchestrated by RNA-binding proteins (RBPs). RBP dysfunction and global splicing dysregulation have been implicated in many human diseases, but the in vivo functions of most RBPs and the splicing outcome upon their loss remain largely unexplored. Here we report that constitutive deletion of Rbm17, which encodes an RBP with a putative role in splicing, causes early embryonic lethality in mice and that its loss in Purkinje neurons leads to rapid degeneration. Transcriptome profiling of Rbm17-deficient and control neurons and subsequent splicing analyses using CrypSplice, a new computational method that we developed, revealed that more than half of RBM17-dependent splicing changes are cryptic. Importantly, RBM17 represses cryptic splicing of genes that likely contribute to motor coordination and cell survival. This finding prompted us to re-analyze published datasets from a recent report on TDP-43, an RBP implicated in amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), as it was demonstrated that TDP-43 represses cryptic exon splicing to promote cell survival. We uncovered a large number of TDP-43-dependent splicing defects that were not previously discovered, revealing that TDP-43 extensively regulates cryptic splicing. Moreover, we found a significant overlap in genes that undergo both RBM17- and TDP-43-dependent cryptic splicing repression, many of which are associated with survival. We propose that repression of cryptic splicing by RBPs is critical for neuronal health and survival. CrypSplice is available at www.liuzlab.org/CrypSplice.
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Affiliation(s)
- Qiumin Tan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Hari Krishna Yalamanchili
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Jeehye Park
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Antonia De Maio
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Program in Developmental Biology
| | - Hsiang-Chih Lu
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Program in Developmental Biology
| | - Ying-Wooi Wan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Joshua J White
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Neuroscience.,Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Vitaliy V Bondar
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Layal S Sayegh
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Xiuyun Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Yan Gao
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA
| | - Roy V Sillitoe
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Program in Developmental Biology.,Department of Neuroscience.,Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Harry T Orr
- Institute for Translational Neuroscience.,Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota 55455, USA
| | - Zhandong Liu
- Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Department of Pediatrics
| | - Huda Y Zoghbi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.,Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, Texas 77030, USA.,Program in Developmental Biology.,Department of Neuroscience.,Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas 77030, USA
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13
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Jagtap PKA, Garg D, Kapp TG, Will CL, Demmer O, Lührmann R, Kessler H, Sattler M. Rational Design of Cyclic Peptide Inhibitors of U2AF Homology Motif (UHM) Domains To Modulate Pre-mRNA Splicing. J Med Chem 2016; 59:10190-10197. [PMID: 27753493 DOI: 10.1021/acs.jmedchem.6b01118] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
U2AF homology motifs (UHMs) are atypical RNA recognition motif domains that mediate critical protein-protein interactions during the regulation of alternative pre-mRNA splicing and other processes. The recognition of UHM domains by UHM ligand motif (ULM) peptide sequences plays important roles during early steps of spliceosome assembly. Splicing factor 45 kDa (SPF45) is an alternative splicing factor implicated in breast and lung cancers, and splicing regulation of apoptosis-linked pre-mRNAs by SPF45 was shown to depend on interactions between its UHM domain and ULM motifs in constitutive splicing factors. We have developed cyclic peptide inhibitors that target UHM domains. By screening a focused library of linear and cyclic peptides and performing structure-activity relationship analysis, we designed cyclic peptides with 4-fold improved binding affinity for the SPF45 UHM domain compared to native ULM ligands and 270-fold selectivity to discriminate UHM domains from alternative and constitutive splicing factors. These inhibitors are useful tools to modulate and dissect mechanisms of alternative splicing regulation.
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Affiliation(s)
- Pravin Kumar Ankush Jagtap
- Institute of Structural Biology, Helmholtz Zentrum München , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.,Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Divita Garg
- Institute of Structural Biology, Helmholtz Zentrum München , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.,Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Tobias G Kapp
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany.,Institute for Advanced Study (IAS), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Cindy L Will
- Max Planck Institute for Biophysical Chemistry , Department of Cellular Biochemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Oliver Demmer
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany.,Institute for Advanced Study (IAS), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Reinhard Lührmann
- Max Planck Institute for Biophysical Chemistry , Department of Cellular Biochemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Horst Kessler
- Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany.,Institute for Advanced Study (IAS), Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München , Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.,Center for Integrated Protein Science Munich (CIPSM), Department Chemie, Technische Universität München , Lichtenbergstrasse 4, 85747 Garching, Germany
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14
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de Necochea-Campion R, Shouse GP, Zhou Q, Mirshahidi S, Chen CS. Aberrant splicing and drug resistance in AML. J Hematol Oncol 2016; 9:85. [PMID: 27613060 PMCID: PMC5018179 DOI: 10.1186/s13045-016-0315-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/02/2016] [Indexed: 02/08/2023] Open
Abstract
The advent of next-generation sequencing technologies has unveiled a new window into the heterogeneity of acute myeloid leukemia (AML). In particular, recurrent mutations in spliceosome machinery and genome-wide aberrant splicing events have been recognized as a prominent component of this disease. This review will focus on how these factors influence drug resistance through altered splicing of tumor suppressor and oncogenes and dysregulation of the apoptotic signaling network. A better understanding of these factors in disease progression is necessary to design appropriate therapeutic strategies recognizing specific alternatively spliced or mutated oncogenic targets.
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Affiliation(s)
- Rosalia de Necochea-Campion
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Geoffrey P Shouse
- Division of Hematology/Oncology, Loma Linda University School of Medicine, 11175 Campus Street, Chan Shun Pavilion 11015, Loma Linda, CA, 92354, USA
| | - Qi Zhou
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Saied Mirshahidi
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Chien-Shing Chen
- Biospecimen Laboratory, Loma Linda University Cancer Center, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA. .,Division of Hematology/Oncology, Loma Linda University School of Medicine, 11175 Campus Street, Chan Shun Pavilion 11015, Loma Linda, CA, 92354, USA.
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15
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Kim SY, Sim CK, Tang H, Han W, Zhang K, Xu F. Acetylome study in mouse adipocytes identifies targets of SIRT1 deacetylation in chromatin organization and RNA processing. Arch Biochem Biophys 2016; 598:1-10. [PMID: 27021582 DOI: 10.1016/j.abb.2016.03.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/29/2016] [Accepted: 03/24/2016] [Indexed: 01/24/2023]
Abstract
SIRT1 is a key protein deacetylase that regulates cellular metabolism through lysine deacetylation on both histones and non-histone proteins. Lysine acetylation is a wide-spread post-translational modification found on many regulatory proteins and it plays an essential role in cell signaling, transcription and metabolism. In mice, SIRT1 has known protective functions during high-fat diet but the acetylome regulated by SIRT1 in adipocytes is not completely understood. Here we conducted acetylome analyses in murine adipocytes treated with small-molecule modulators that inhibit or activate the deacetylase activity of SIRT1. We identified a total of 302 acetylated peptides from 78 proteins in this study. From the list of potential SIRT1 targets, we selected seven candidates and further verified that six of them can be deacetylated by SIRT1 in-vitro. Among them, half of the SIRT1 targets are involved in regulating chromatin structure and the other half is involved in RNA processing. Our results provide a resource for further SIRT1 target validation in fat cells and suggest a potential role of SIRT1 in the regulation of chromatin structure and RNA processing, which may possibly extend to other cell types as well.
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Affiliation(s)
- Sun-Yee Kim
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), 30 Medical Drive, Singapore 117609, Singapore
| | - Choon Kiat Sim
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), 30 Medical Drive, Singapore 117609, Singapore
| | - Hui Tang
- Department of Pharmacology and Toxicology, UTMB at Galveston, TX 77554, USA
| | - Weiping Han
- Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, Singapore 138667, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117596, Singapore; Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore
| | - Kangling Zhang
- Department of Pharmacology and Toxicology, UTMB at Galveston, TX 77554, USA.
| | - Feng Xu
- Singapore Institute for Clinical Sciences, Agency for Science, Technology and Research (A*STAR), 30 Medical Drive, Singapore 117609, Singapore; Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, 8 Medical Drive, Singapore 117596, Singapore; Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore.
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16
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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: 96] [Impact Index Per Article: 10.7] [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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17
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Splicing Regulation: A Molecular Device to Enhance Cancer Cell Adaptation. BIOMED RESEARCH INTERNATIONAL 2015; 2015:543067. [PMID: 26273627 PMCID: PMC4529921 DOI: 10.1155/2015/543067] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 03/23/2015] [Indexed: 01/23/2023]
Abstract
Alternative splicing (AS) represents a major resource for eukaryotic cells to expand the coding potential of their genomes and to finely regulate gene expression in response to both intra- and extracellular cues. Cancer cells exploit the flexible nature of the mechanisms controlling AS in order to increase the functional diversity of their proteome. By altering the balance of splice isoforms encoded by human genes or by promoting the expression of aberrant oncogenic splice variants, cancer cells enhance their ability to adapt to the adverse growth conditions of the tumoral microenvironment. Herein, we will review the most relevant cancer-related splicing events and the underlying regulatory mechanisms allowing tumour cells to rapidly adapt to the harsh conditions they may face during the occurrence and development of cancer.
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18
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Wojtuszkiewicz A, Assaraf YG, Maas MJP, Kaspers GJL, Jansen G, Cloos J. Pre-mRNA splicing in cancer: the relevance in oncogenesis, treatment and drug resistance. Expert Opin Drug Metab Toxicol 2014; 11:673-89. [PMID: 25495223 DOI: 10.1517/17425255.2015.993316] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Aberrant pre-mRNA splicing in cancer is emerging as an important determinant of oncogenesis, response to treatment and anticancer drug resistance. At the same time, the spliceosome has become a target for a novel class of pre-clinical chemotherapeutics with a potential future application in cancer treatment. Taken together, these findings offer novel opportunities for the enhancement of the efficacy of cancer therapy. AREAS COVERED This review presents a comprehensive overview of the molecular mechanisms involved in splicing and current developments regarding splicing aberrations in relation to several aspects of cancer formation and therapy. Identified mutations in the various components of the spliceosome and their implications for cancer prognosis are delineated. Moreover, the contribution of abnormal splicing patterns as well as deregulated splicing factors to chemoresistance is discussed, along with novel splicing-based therapeutic approaches. EXPERT OPINION Significant progress has been made in deciphering the role of splicing factors in cancer including carcinogenesis and drug resistance. Splicing-based prognostic tools as well as therapeutic options hold great potential towards improvements in cancer therapy. However, gaining more in-depth molecular insight into the consequences of mutations in various components of the splicing machinery as well as of cellular effects of spliceosome inhibition is a prerequisite to establish the role of splicing in tumor progression and treatment options, respectively.
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Affiliation(s)
- Anna Wojtuszkiewicz
- VU University Medical Center, Department of Pediatric Oncology/Hematology , Amsterdam , The Netherlands
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19
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Genovese F, Gualandi A, Taddia L, Marverti G, Pirondi S, Marraccini C, Perco P, Pelà M, Guerrini R, Amoroso MR, Esposito F, Martello A, Ponterini G, D’Arca D, Costi MP. Mass Spectrometric/Bioinformatic Identification of a Protein Subset That Characterizes the Cellular Activity of Anticancer Peptides. J Proteome Res 2014; 13:5250-61. [DOI: 10.1021/pr500510v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Filippo Genovese
- C.I.G.S., University of Modena and Reggio Emilia, Via
G. Campi 213/A, Modena 41125, Italy
| | - Alessandra Gualandi
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Laura Taddia
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Gaetano Marverti
- Department
of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 183, Modena 41125, Italy
| | - Silvia Pirondi
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Chiara Marraccini
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Paul Perco
- Emergentec biodevelopment GmbH, Gersthofer Straße 29-31, Wien 1180, Austria
| | - Michela Pelà
- Department
of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17-19, Ferrara 44100, Italy
| | - Remo Guerrini
- Department
of Chemical and Pharmaceutical Sciences, University of Ferrara, Via Fossato di Mortara 17-19, Ferrara 44100, Italy
| | - Maria Rosaria Amoroso
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Franca Esposito
- Department
of Molecular Medicine and Medical Biotechnology, University of Naples “Federico II”, Via S. Pansini 5, Napoli 80131, Italy
| | - Andrea Martello
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Glauco Ponterini
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
| | - Domenico D’Arca
- Department
of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Via Giuseppe Campi 183, Modena 41125, Italy
| | - Maria Paola Costi
- Department
of Life Sciences, University of Modena and Reggio Emilia, Via Giuseppe
Campi 183, Modena 41125, Italy
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20
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Liu Y, Conaway L, Rutherford Bethard J, Al-Ayoubi AM, Thompson Bradley A, Zheng H, Weed SA, Eblen ST. Phosphorylation of the alternative mRNA splicing factor 45 (SPF45) by Clk1 regulates its splice site utilization, cell migration and invasion. Nucleic Acids Res 2013; 41:4949-62. [PMID: 23519612 PMCID: PMC3643583 DOI: 10.1093/nar/gkt170] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alternative mRNA splicing is a mechanism to regulate protein isoform expression and is regulated by alternative splicing factors. The alternative splicing factor 45 (SPF45) is overexpressed in cancer, although few biological effects of SPF45 are known, and few splicing targets have been identified. We previously showed that Extracellular Regulated Kinase 2 (ERK2) phosphorylation of SPF45 regulates cell proliferation and adhesion to fibronectin. In this work, we show that Cdc2-like kinase 1 (Clk1) phosphorylates SPF45 on eight serine residues. Clk1 expression enhanced, whereas Clk1 inhibition reduced, SPF45-induced exon 6 exclusion from Fas mRNA. Mutational analysis of the Clk1 phosphorylation sites on SPF45 showed both positive and negative regulation of splicing, with a net effect of inhibiting SPF45-induced exon 6 exclusion, correlating with reduced Fas mRNA binding. However, Clk1 enhanced SPF45 protein expression, but not mRNA expression, whereas inhibition of Clk1 increased SPF45 degradation through a proteasome-dependent pathway. Overexpression of SPF45 or a phospho-mimetic mutant, but not a phospho-inhibitory mutant, stimulated ovarian cancer cell migration and invasion, correlating with increased fibronectin expression, ERK activation and enhanced splicing and phosphorylation of full-length cortactin. Our results demonstrate for the first time that SPF45 overexpression enhances cell migration and invasion, dependent on biochemical regulation by Clk1.
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Affiliation(s)
- Yuying Liu
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, 173 Ashley Ave, Charleston, SC 29425, USA
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21
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The role of hormonal factors and endocrine therapy in ovarian cancer. Contemp Oncol (Pozn) 2013; 17:14-9. [PMID: 23788955 PMCID: PMC3685340 DOI: 10.5114/wo.2013.33768] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Revised: 08/14/2011] [Accepted: 11/04/2011] [Indexed: 11/22/2022] Open
Abstract
The efficacy of the second-line chemotherapy commonly used in both relapsed ovarian cancer patients and those with primary treatment failure remains unsatisfactory. This therapy has a small effect on survival, whereas associated toxicity may diminish the patient's quality of life. Hormonal factors play a role in ovarian tumorigenesis, and inhibition of the stimulating effects of estrogens may exert a clinical benefit. The role of hormonal therapy as a palliative therapeutic alternative for ovarian cancer remains undetermined. This modality may result in long-term stabilization of disease in individual patients and less frequently in tumor remission. In this article the role of hormonal factors and recent literature of various forms of hormonal therapy for ovarian cancer are presented.
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22
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Abstract
For most of our 25,000 genes, the removal of introns by pre-messenger RNA (pre-mRNA) splicing represents an essential step toward the production of functional messenger RNAs (mRNAs). Alternative splicing of a single pre-mRNA results in the production of different mRNAs. Although complex organisms use alternative splicing to expand protein function and phenotypic diversity, patterns of alternative splicing are often altered in cancer cells. Alternative splicing contributes to tumorigenesis by producing splice isoforms that can stimulate cell proliferation and cell migration or induce resistance to apoptosis and anticancer agents. Cancer-specific changes in splicing profiles can occur through mutations that are affecting splice sites and splicing control elements, and also by alterations in the expression of proteins that control splicing decisions. Recent progress in global approaches that interrogate splicing diversity should help to obtain specific splicing signatures for cancer types. The development of innovative approaches for annotating and reprogramming splicing events will more fully establish the essential contribution of alternative splicing to the biology of cancer and will hopefully provide novel targets and anticancer strategies. Metazoan genes are usually made up of several exons interrupted by introns. The introns are removed from the pre-mRNA by RNA splicing. In conjunction with other maturation steps, such as capping and polyadenylation, the spliced mRNA is then transported to the cytoplasm to be translated into a functional protein. The basic mechanism of splicing requires accurate recognition of each extremity of each intron by the spliceosome. Introns are identified by the binding of U1 snRNP to the 5' splice site and the U2AF65/U2AF35 complex to the 3' splice site. Following these interactions, other proteins and snRNPs are recruited to generate the complete spliceosomal complex needed to excise the intron. While many introns are constitutively removed by the spliceosome, other splice junctions are not used systematically, generating the phenomenon of alternative splicing. Alternative splicing is therefore the process by which a single species of pre-mRNA can be matured to produce different mRNA molecules (Fig. 1). Depending on the number and types of alternative splicing events, a pre-mRNA can generate from two to several thousands different mRNAs leading to the production of a corresponding number of proteins. It is now believed that the expression of at least 70 % of human genes is subjected to alternative splicing, implying an enormous contribution to proteomic diversity, and by extension, to the development and the evolution of complex animals. Defects in splicing have been associated with human diseases (Caceres and Kornblihtt, Trends Genet 18(4):186-93, 2002, Cartegni et al., Nat Rev Genet 3(4):285-98, 2002, Pagani and Baralle, Nat Rev Genet 5(5):389-96, 2004), including cancer (Brinkman, Clin Biochem 37(7):584-94, 2004, Venables, Bioessays 28(4):378-86, 2006, Srebrow and Kornblihtt, J Cell Sci 119(Pt 13):2635-2641, 2006, Revil et al., Bull Cancer 93(9):909-919, 2006, Venables, Transworld Res Network, 2006, Pajares et al., Lancet Oncol 8(4):349-57, 2007, Skotheim and Nees, Int J Biochem Cell Biol 39:1432-1449, 2007). Numerous studies have now confirmed the existence of specific differences in the alternative splicing profiles between normal and cancer tissues. Although there are a few cases where specific mutations are the primary cause for these changes, global alterations in alternative splicing in cancer cells may be primarily derived from changes in the expression of RNA-binding proteins that control splice site selection. Overall, these cancer-specific differences in alternative splicing offer an immense potential to improve the diagnosis and the prognosis of cancer. This review will focus on the functional impact of cancer-associated alternative splicing variants, the molecular determinants that alter the splicing decisions in cancer cells, and future therapeutic strategies.
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Mitogen-activated protein kinase phosphorylation of splicing factor 45 (SPF45) regulates SPF45 alternative splicing site utilization, proliferation, and cell adhesion. Mol Cell Biol 2012; 32:2880-93. [PMID: 22615491 DOI: 10.1128/mcb.06327-11] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The regulation of alternative mRNA splicing factors by extracellular cues and signal transduction cascades is poorly understood. Using an engineered extracellular signal-regulated kinase 2 (ERK2) that can utilize ATP analogs, we have identified the alternative mRNA splicing factor 45 (SPF45), which is overexpressed in cancer, as a novel coimmunoprecipitating ERK2 substrate. ERK2 phosphorylated SPF45 on Thr71 and Ser222 in vitro and in cells in response to H-RasV12, B-RAF-V600E, and activated MEK1. Jun N-terminal kinase 1 (JNK1) and p38α also phosphorylated SPF45 in vitro and associated with SPF45 in cells. SPF45 was differentially phosphorylated in cells by all three mitogen-activated protein (MAP) kinases in response to phorbol myristate acid (PMA), H(2)O(2), UV, and anisomycin stimulation. ERK and p38 activation decreased SPF45-dependent exon 6 exclusion from fas mRNA in a minigene assay in cells. Stable overexpression of SPF45 in SKOV-3 cells dramatically inhibited cell proliferation in a phosphorylation-dependent manner through inhibition of ErbB2 expression. SPF45 overexpression also induced EDA inclusion into fibronectin transcripts and fibronectin expression in a phosphorylation-dependent and -independent manner, respectively, specifically affecting cellular adhesion to a fibronectin matrix. These data identify SPF45 as the first splicing factor regulated by multiple MAP kinase pathways and show effects of both SPF45 overexpression and phosphorylation.
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Eblen ST. Regulation of chemoresistance via alternative messenger RNA splicing. Biochem Pharmacol 2012; 83:1063-72. [PMID: 22248731 DOI: 10.1016/j.bcp.2011.12.041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/29/2011] [Accepted: 12/29/2011] [Indexed: 12/17/2022]
Abstract
The acquisition of resistance to chemotherapy is a significant problem in the treatment of cancer, greatly increasing patient morbidity and mortality. Tumors are often sensitive to chemotherapy upon initial treatment, but repeated treatments can select for those cells that were able to survive initial therapy and have acquired cellular mechanisms to enhance their resistance to subsequent chemotherapy treatment. Many cellular mechanisms of drug resistance have been identified, most of which result from changes in gene and protein expression. While changes at the transcriptional level have been duly noted, it is primarily the post-transcriptional processing of pre-mRNA into mature mRNA that regulates the composition of the proteome and it is the proteome that actually regulates the cell's response to chemotherapeutic insult, inducing cell survival or death. During pre-mRNA processing, intronic non-protein-coding sequences are removed and protein-coding exons are spliced to form a continuous template for protein translation. Alternative splicing involves the differential inclusion or exclusion of exonic sequences into the mature transcript, generating different mRNA templates for protein production. This regulatory mechanism enables the potential to produce many different protein isoforms from the same gene. In this review I will explain the mechanism of alternative pre-mRNA splicing and look at some specific examples of how splicing factors, splicing factor kinases and alternative splicing of specific pre-mRNAs from genes have been shown to contribute to acquisition of the drug resistant phenotype.
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Affiliation(s)
- Scott T Eblen
- Department of Cell and Molecular Pharmacology, Medical University of South Carolina, Charleston, 29425, USA.
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Horikoshi N, Morozumi Y, Takaku M, Takizawa Y, Kurumizaka H. Holliday junction-binding activity of human SPF45. Genes Cells 2010; 15:373-83. [PMID: 20236180 DOI: 10.1111/j.1365-2443.2010.01383.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
SPF45 is considered to be a bifunctional protein that functions in splicing and DNA repair. A previous genetic study reported that Drosophila SPF45 participates in the DNA-repair pathway with a RAD51-family protein, RAD201, suggesting that SPF45 may function in DNA repair by the homologous-recombination pathway. To study the function of SPF45 in homologous recombination, we purified human SPF45 and found that it preferentially binds to the Holliday junction, which is a key DNA intermediate in the homologous-recombination pathway. Deletion analyses revealed that the RNA recognition motif, which is located in the C-terminal region of human SPF45, is not involved in DNA binding. On the other hand, alanine-scanning mutagenesis identified the N-terminal lysine residues, which may be involved in Holliday junction binding by human SPF45. We also found that human SPF45 significantly binds to a RAD51 paralog, RAD51B, although it also binds to RAD51 and DMC1 with lower affinity. These biochemical results support the idea that human SPF45 functions in DNA repair by homologous recombination.
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Affiliation(s)
- Naoki Horikoshi
- Laboratory of Structural Biology, Graduate School of Advanced Science and Engineering, Waseda University, 2-2 Wakamatsu-cho, Shinjuku-ku, Tokyo 162-8480, Japan
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Aberrant splicing of folylpolyglutamate synthetase as a novel mechanism of antifolate resistance in leukemia. Blood 2009; 113:4362-9. [DOI: 10.1182/blood-2008-08-173799] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Folylpoly-γ-gluatamate synthetase (FPGS) catalyzes the polyglutamylation and thus intracellular retention of folates and antifolates (eg, methotrexate; MTX) through the addition of multiple glutamate equivalents to their γ-carboxyl residue. Since polyglutamylation of antifolates is crucial for their pharmacological activity in leukemia, loss of FPGS function results in decreased cellular levels of polyglutamylation-dependent antifolates and consequent drug resistance. Whereas resistance to pulse exposure to antifolates is frequently associated with loss of FPGS activity, the underlying molecular mechanism remains elusive. Here we explored the molecular basis of antifolate resistance in human MTX-resistant leukemia cell lines displaying marked loss of FPGS activity. We demonstrate that these MTX-resistant cells exhibit impaired splicing of FPGS mRNA based on intron retention and/or exon skipping, thereby resulting in loss of FPGS function due to premature translation termination. Furthermore, analysis of FPGS transcripts in blood or bone marrow specimens from patients with acute lymphoblastic leukemia revealed exon 12 skipping, both at diagnosis and at relapse, the latter of which occurs after high-dose MTX-containing chemotherapy. These results constitute the first demonstration of the loss of FPGS function via aberrant mRNA splicing, thereby resulting in loss of antifolate retention and drug resistance. The clinical ramifications of these novel findings are discussed.
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Passetti F, Ferreira CG, Costa FF. The impact of microRNAs and alternative splicing in pharmacogenomics. THE PHARMACOGENOMICS JOURNAL 2009; 9:1-13. [PMID: 19156160 DOI: 10.1038/tpj.2008.14] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- F Passetti
- Laboratory of Bioinformatics and Computational Biology, Division of Clinical and Translational Research, Research Coordination (CPQ), Instituto Nacional de Câncer, Rio de Janeiro, Brazil
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Shen Y, Tang H, Radosz M, Van Kirk E, Murdoch WJ. pH-responsive nanoparticles for cancer drug delivery. Methods Mol Biol 2008; 437:183-216. [PMID: 18369970 DOI: 10.1007/978-1-59745-210-6_10] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Solid tumors have an acidic extracellular environment and an altered pH gradient across their cell compartments. Nanoparticles responsive to the pH gradients are promising for cancer drug delivery. Such pH-responsive nanoparticles consist of a corona and a core, one or both of which respond to the external pH to change their soluble/insoluble or charge states. Nanoparticles whose coronas become positively charged or become soluble to make their targeting groups available for binding at the tumor extracellular pH have been developed for promoting cellular targeting and internalization. Nanoparticles whose cores become soluble or change their structures to release the carried drugs at the tumor extracellular pH or lysosomal pH have been developed for fast drug release into the extracellular fluid or cytosol. Such pH-responsive nanoparticles have therapeutic advantages over the conventional pH-insensitive counterparts.
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Affiliation(s)
- Youqing Shen
- Soft Materials Laboratory, Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, WY, USA
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Chaouki AS, Salz HK. Drosophila SPF45: a bifunctional protein with roles in both splicing and DNA repair. PLoS Genet 2007; 2:e178. [PMID: 17154718 PMCID: PMC1687153 DOI: 10.1371/journal.pgen.0020178] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 09/01/2006] [Indexed: 11/18/2022] Open
Abstract
The sequence of the SPF45 protein is significantly conserved, yet functional studies have identified it as a splicing factor in animal cells and as a DNA-repair protein in plants. Using a combined genetic and biochemical approach to investigate this apparent functional discrepancy, we unify and validate both of these studies by demonstrating that the Drosophila melanogaster protein is bifunctional, with independent functions in DNA repair and splicing. We find that SPF45 associates with the U2 snRNP and that mutations that remove the C-terminal end of the protein disrupt this interaction. Although animals carrying this mutation are viable, they are nevertheless compromised in their ability to regulate Sex-lethal splicing, demonstrating that Sex-lethal is an important physiological target of SPF45. Furthermore, these mutant animals exhibit phenotypes diagnostic of difficulties in recovering from exogenously induced DNA damage. The conclusion that SPF45 functions in the DNA-repair pathway is strengthened by finding both genetic and physical interactions between SPF45 and RAD201, a previously uncharacterized member of the RecA/Rad51 protein family. Together with our finding that the fly SPF45 protein increases the survival rate of mutagen-treated bacteria lacking the RecG helicase, these studies provide the tantalizing suggestion that SPF45 has an ancient and evolutionarily conserved role in DNA repair. Assigning function to a protein relies on information about similar proteins in different species, and is based on the view that conservation of sequence generally parallels conservation of function. In this article, Chaouki and Salz focus on SPF45, a protein that, at first glance, appears to break this rule. Although the sequence of SPF45 is highly conserved, in animals cells SPF45 functions as a splicing factor, but in plant cells it functions as a DNA repair protein. This functional discrepancy is resolved here through the demonstration that, in D. melanogaster, SPF45 is a bifunctional protein with independent functions in DNA repair and splicing. Support for this conclusion includes the observation that mutant animals lacking SPF45 function display defects in both splicing and DNA repair. In addition, the authors show that SPF45 associates with two distinct groups of proteins; those that participate in RNA splicing and those that participate in DNA repair. The finding that the D. melanogaster protein is bifunctional suggests that the human protein may also have more than one function. This has important clinical implications because elevated SPF45 levels have been correlated with resistance to chemotherapy.
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Affiliation(s)
- Ahmad Sami Chaouki
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Helen K Salz
- Department of Genetics, School of Medicine, Case Western Reserve University, Cleveland, Ohio, United States of America
- * To whom correspondence should be addressed. E-mail:
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Stewart DJ. Mechanisms of resistance to cisplatin and carboplatin. Crit Rev Oncol Hematol 2007; 63:12-31. [PMID: 17336087 DOI: 10.1016/j.critrevonc.2007.02.001] [Citation(s) in RCA: 455] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Revised: 01/25/2007] [Accepted: 02/02/2007] [Indexed: 02/08/2023] Open
Abstract
While cisplatin and carboplatin are active versus most common cancers, epithelial malignancies are incurable when metastatic. Even if an initial response occurs, acquired resistance due to mutations and epigenetic events limits efficacy. Resistance may be due to excess of a resistance factor, to saturation of factors required for tumor cell killing, or to mutation or alteration of a factor required for tumor cell killing. Platinum resistance could arise from decreased tumor blood flow, extracellular conditions, reduced platinum uptake, increased efflux, intracellular detoxification by glutathione, etc., decreased binding (e.g., due to high intracellular pH), DNA repair, decreased mismatch repair, defective apoptosis, antiapoptotic factors, effects of several signaling pathways, or presence of quiescent non-cycling cells. In lung cancer, flattening of dose-response curves at higher doses suggests that efficacy is limited by exhaustion of something required for cell killing, and several clinical observations suggest epigenetic events may play a major role in resistance.
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Affiliation(s)
- David J Stewart
- Section of Experimental Therapeutics, Department of Thoracic/Head & Neck Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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