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Zhang J, Xu X, Deng H, Liu L, Xiang Y, Feng J. Overcoming cancer drug-resistance calls for novel strategies targeting abnormal alternative splicing. Pharmacol Ther 2024; 261:108697. [PMID: 39025436 DOI: 10.1016/j.pharmthera.2024.108697] [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: 03/02/2024] [Revised: 05/12/2024] [Accepted: 07/15/2024] [Indexed: 07/20/2024]
Abstract
Abnormal gene alternative splicing (AS) events are strongly associated with cancer progression. Here, we summarize AS events that contribute to the development of drug resistance and classify them into three categories: alternative cis-splicing (ACS), alternative trans-splicing (ATS), and alternative back-splicing (ABS). The regulatory mechanisms underlying AS processes through cis-acting regulatory elements and trans-acting factors are comprehensively described, and the distinct functions of spliced variants, including linear spliced variants derived from ACS, chimeric spliced variants arising from ATS, and circRNAs generated through ABS, are discussed. The identification of dysregulated spliced variants, which contribute to drug resistance and hinder effective cancer treatment, suggests that abnormal AS processes may together serve as a precise regulatory mechanism enabling drug-resistant cancer cell survival or, alternatively, represent an evolutionary pathway for cancer cells to adapt to changes in the external environment. Moreover, this review summarizes recent advancements in treatment approaches targeting AS-associated drug resistance, focusing on cis-acting regulatory elements, trans-acting factors, and specific spliced variants. Collectively, gaining an in-depth understanding of the mechanisms underlying aberrant alternative splicing events and developing strategies to target this process hold great promise for overcoming cancer drug resistance.
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Affiliation(s)
- Ji Zhang
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Xinyu Xu
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Hongwei Deng
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Li Liu
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China
| | - Yuancai Xiang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southwest Medical University, Luzhou city, Sichuan 646000, China.
| | - Jianguo Feng
- Department of Anesthesiology, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Anesthesiology and Critical Care Medicine Key Laboratory of Luzhou, The Affiliated Hospital, Southwest Medical University, Luzhou, Sichuan Province 646000, China; Nucleic Acid Medicine of Luzhou Key Laboratory, Southwest Medical University, Luzhou, Sichuan Province 646000, China.
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2
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Choi S, Cho N, Kim EM, Kim KK. The role of alternative pre-mRNA splicing in cancer progression. Cancer Cell Int 2023; 23:249. [PMID: 37875914 PMCID: PMC10594706 DOI: 10.1186/s12935-023-03094-3] [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: 09/06/2023] [Accepted: 10/06/2023] [Indexed: 10/26/2023] Open
Abstract
Alternative pre-mRNA splicing is a critical mechanism that generates multiple mRNA from a single gene, thereby increasing the diversity of the proteome. Recent research has highlighted the significance of specific splicing isoforms in cellular processes, particularly in regulating cell numbers. In this review, we examine the current understanding of the role of alternative splicing in controlling cancer cell growth and discuss specific splicing factors and isoforms and their molecular mechanisms in cancer progression. These isoforms have been found to intricately control signaling pathways crucial for cell cycle progression, proliferation, and apoptosis. Furthermore, studies have elucidated the characteristics and functional importance of splicing factors that influence cell numbers. Abnormal expression of oncogenic splicing isoforms and splicing factors, as well as disruptions in splicing caused by genetic mutations, have been implicated in the development and progression of tumors. Collectively, these findings provide valuable insights into the complex interplay between alternative splicing and cell proliferation, thereby suggesting the potential of alternative splicing as a therapeutic target for cancer.
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Affiliation(s)
- Sunkyung Choi
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Namjoon Cho
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Eun-Mi Kim
- Department of Predictive Toxicology, Korea Institute of Toxicology, Daejeon, 34114, Republic of Korea.
| | - Kee K Kim
- Department of Biochemistry, College of Natural Sciences, Chungnam National University, Daejeon, 34134, Republic of Korea.
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3
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Vujovic A, de Rooij L, Chahi AK, Chen HT, Yee BA, Loganathan SK, Liu L, Chan DC, Tajik A, Tsao E, Moreira S, Joshi P, Xu J, Wong N, Balde Z, Jahangiri S, Zandi S, Aigner S, Dick JE, Minden MD, Schramek D, Yeo GW, Hope KJ. In Vivo Screening Unveils Pervasive RNA-Binding Protein Dependencies in Leukemic Stem Cells and Identifies ELAVL1 as a Therapeutic Target. Blood Cancer Discov 2023; 4:180-207. [PMID: 36763002 PMCID: PMC10150294 DOI: 10.1158/2643-3230.bcd-22-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 11/30/2022] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Acute myeloid leukemia (AML) is fueled by leukemic stem cells (LSC) whose determinants are challenging to discern from hematopoietic stem cells (HSC) or uncover by approaches focused on general cell properties. We have identified a set of RNA-binding proteins (RBP) selectively enriched in human AML LSCs. Using an in vivo two-step CRISPR-Cas9 screen to assay stem cell functionality, we found 32 RBPs essential for LSCs in MLL-AF9;NrasG12D AML. Loss-of-function approaches targeting key hit RBP ELAVL1 compromised LSC-driven in vivo leukemic reconstitution, and selectively depleted primitive malignant versus healthy cells. Integrative multiomics revealed differentiation, splicing, and mitochondrial metabolism as key features defining the leukemic ELAVL1-mRNA interactome with mitochondrial import protein, TOMM34, being a direct ELAVL1-stabilized target whose repression impairs AML propagation. Altogether, using a stem cell-adapted in vivo CRISPR screen, this work demonstrates pervasive reliance on RBPs as regulators of LSCs and highlights their potential as therapeutic targets in AML. SIGNIFICANCE LSC-targeted therapies remain a significant unmet need in AML. We developed a stem-cell-adapted in vivo CRISPR screen to identify key LSC drivers. We uncover widespread RNA-binding protein dependencies in LSCs, including ELAVL1, which we identify as a novel therapeutic vulnerability through its regulation of mitochondrial metabolism. This article is highlighted in the In This Issue feature, p. 171.
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Affiliation(s)
- Ana Vujovic
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Laura de Rooij
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Ava Keyvani Chahi
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - He Tian Chen
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Brian A. Yee
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California
| | - Sampath K. Loganathan
- Centre for Molecular and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Lina Liu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Derek C.H. Chan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Amanda Tajik
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Emily Tsao
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Steven Moreira
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Pratik Joshi
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Joshua Xu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Nicholas Wong
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Zaldy Balde
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Soheil Jahangiri
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
| | - Sasan Zandi
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Stefan Aigner
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California
| | - John E. Dick
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Mark D. Minden
- Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
- Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Daniel Schramek
- Centre for Molecular and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Gene W. Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California
| | - Kristin J. Hope
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Canada
- Princess Margaret Cancer Centre, University Health Network, Toronto, Canada
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Kumar K, Sinha SK, Maity U, Kirti PB, Kumar KRR. Insights into established and emerging roles of SR protein family in plants and animals. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1763. [PMID: 36131558 DOI: 10.1002/wrna.1763] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 08/11/2022] [Accepted: 08/22/2022] [Indexed: 05/13/2023]
Abstract
Splicing of pre-mRNA is an essential part of eukaryotic gene expression. Serine-/arginine-rich (SR) proteins are highly conserved RNA-binding proteins present in all metazoans and plants. SR proteins are involved in constitutive and alternative splicing, thereby regulating the transcriptome and proteome diversity in the organism. In addition to their role in splicing, SR proteins are also involved in mRNA export, nonsense-mediated mRNA decay, mRNA stability, and translation. Due to their pivotal roles in mRNA metabolism, SR proteins play essential roles in normal growth and development. Hence, any misregulation of this set of proteins causes developmental defects in both plants and animals. SR proteins from the animal kingdom are extensively studied for their canonical and noncanonical functions. Compared with the animal kingdom, plant genomes harbor more SR protein-encoding genes and greater diversity of SR proteins, which are probably evolved for plant-specific functions. Evidence from both plants and animals confirms the essential role of SR proteins as regulators of gene expression influencing cellular processes, developmental stages, and disease conditions. This article is categorized under: RNA Processing > Splicing Mechanisms RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- Kundan Kumar
- Department of Biotechnology, Indira Gandhi National Tribal University (IGNTU), Amarkantak, India
| | - Shubham Kumar Sinha
- Department of Biotechnology, Indira Gandhi National Tribal University (IGNTU), Amarkantak, India
| | - Upasana Maity
- Department of Biotechnology, Indira Gandhi National Tribal University (IGNTU), Amarkantak, India
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5
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Yu L, Majerciak V, Jia R, Zheng ZM. Revisiting and corrections to the annotated SRSF3 (SRp20) gene structure and RefSeq sequences from the human and mouse genomes. CELL INSIGHT 2023; 2:100089. [PMID: 37193066 PMCID: PMC10134197 DOI: 10.1016/j.cellin.2023.100089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/14/2023] [Accepted: 02/18/2023] [Indexed: 05/18/2023]
Abstract
SRSF3 (SRp20) is the smallest member of the serine/arginine (SR)-rich protein family. We found the annotated human SRSF3 and mouse Srsf3 RefSeq sequences are much larger than the detected SRSF3/Srsf3 RNA size by Northern blot. Mapping of RNA-seq reads from various human and mouse cell lines to the annotated SRSF3/Srsf3 gene illustrated only a partial coverage of its terminal exon 7. By 5' RACE and 3' RACE, we determined that SRSF3 gene spanning over 8422 bases and Srsf3 gene spanning over 9423 bases. SRSF3/Srsf3 gene has seven exons with exon 7 bearing two alternative polyadenylation signals (PAS). Through alternative PAS selection and exon 4 exclusion/inclusion by alternative RNA splicing, SRSF3/Srsf3 gene expresses four RNA isoforms. The major SRSF3 mRNA isoform with exon 4 exclusion by using a favorable distal PAS to encode a full-length protein is 1411 nt long (not annotated 4228 nt) and the same major mouse Srsf3 mRNA isoform is only 1295 nt (not annotated 2585 nt). The difference from the redefined RNA size of SRSF3/Srsf3 to the corresponding RefSeq sequence is at the 3' UTR region. Collectively, the redefined SRSF3/Srsf3 gene structure and expression will allow better understanding of SRSF3 functions and its regulations in health and diseases.
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Affiliation(s)
- Lulu Yu
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Vladimir Majerciak
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
| | - Rong Jia
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST), Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, HIV Dynamics and Replication Program, Center for Cancer Research, National Cancer Institute, Frederick, MD, 21702, USA
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6
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De Silva NIU, Fargason T, Zhang Z, Wang T, Zhang J. Inter-domain Flexibility of Human Ser/Arg-Rich Splicing Factor 1 Allows Variable Spacer Length in Cognate RNA’s Bipartite Motifs. Biochemistry 2022; 61:2922-2932. [DOI: 10.1021/acs.biochem.2c00565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Affiliation(s)
- Naiduwadura Ivon Upekala De Silva
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Talia Fargason
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Zihan Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Ting Wang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
| | - Jun Zhang
- Department of Chemistry, College of Arts and Sciences, University of Alabama at Birmingham, CH266, 901 14th Street South, Birmingham, Alabama35294-1240, United States
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7
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Splicing factor SRSF3 represses translation of p21 cip1/waf1 mRNA. Cell Death Dis 2022; 13:933. [PMID: 36344491 PMCID: PMC9640673 DOI: 10.1038/s41419-022-05371-x] [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: 06/15/2022] [Revised: 10/18/2022] [Accepted: 10/24/2022] [Indexed: 11/09/2022]
Abstract
Serine/arginine-rich splicing factor 3 (SRSF3) is an RNA binding protein that most often regulates gene expression at the splicing level. Although the role of SRSF3 in mRNA splicing in the nucleus is well known, its splicing-independent role outside of the nucleus is poorly understood. Here, we found that SRSF3 exerts a translational control of p21 mRNA. Depletion of SRSF3 induces cellular senescence and increases the expression of p21 independent of p53. Consistent with the expression patterns of SRSF3 and p21 mRNA in the TCGA database, SRSF3 knockdown increases the p21 mRNA level and its translation efficiency as well. SRSF3 physically associates with the 3'UTR region of p21 mRNA and the translational initiation factor, eIF4A1. Our study proposes a model in which SRSF3 regulates translation by interacting with eIF4A1 at the 3'UTR region of p21 mRNA. We also found that SRSF3 localizes to the cytoplasmic RNA granule along with eIF4A1, which may assist in translational repression therein. Thus, our results provide a new mode of regulation for p21 expression, a crucial regulator of the cell cycle and senescence, which occurs at the translational level and involves SRSF3.
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8
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Impact of alternative splicing on mechanisms of resistance to anticancer drugs. Biochem Pharmacol 2021; 193:114810. [PMID: 34673012 DOI: 10.1016/j.bcp.2021.114810] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/05/2021] [Accepted: 10/06/2021] [Indexed: 12/15/2022]
Abstract
A shared characteristic of many tumors is the lack of response to anticancer drugs. Multiple mechanisms of pharmacoresistance (MPRs) are involved in permitting cancer cells to overcome the effect of these agents. Pharmacoresistance can be primary (intrinsic) or secondary (acquired), i.e., triggered or enhanced in response to the treatment. Moreover, MPRs usually result in the lack of sensitivity to several agents, which accounts for diverse multidrug-resistant (MDR) phenotypes. MPRs are based on the dynamic expression of more than one hundred genes, constituting the so-called resistome. Alternative splicing (AS) during pre-mRNA maturation results in changes affecting proteins involved in the resistome. The resulting splicing variants (SVs) reduce the efficacy of anticancer drugs by lowering the intracellular levels of active agents, altering molecular targets, enhancing both DNA repair ability and defensive mechanism of tumors, inducing changes in the balance between pro-survival and pro-apoptosis signals, modifying interactions with the tumor microenvironment, and favoring malignant phenotypic transitions. Reasons accounting for cancer-associated aberrant splicing include mutations that create or disrupt splicing sites or splicing enhancers or silencers, abnormal expression of splicing factors, and impaired signaling pathways affecting the activity of the splicing machinery. Here we have reviewed the impact of AS on MPR in cancer cells.
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Serra M, Hattinger CM, Pasello M, Casotti C, Fantoni L, Riganti C, Manara MC. Impact of ABC Transporters in Osteosarcoma and Ewing's Sarcoma: Which Are Involved in Chemoresistance and Which Are Not? Cells 2021; 10:cells10092461. [PMID: 34572110 PMCID: PMC8467338 DOI: 10.3390/cells10092461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 12/16/2022] Open
Abstract
The ATP-binding cassette (ABC) transporter superfamily consists of several proteins with a wide repertoire of functions. Under physiological conditions, ABC transporters are involved in cellular trafficking of hormones, lipids, ions, xenobiotics, and several other molecules, including a broad spectrum of chemical substrates and chemotherapeutic drugs. In cancers, ABC transporters have been intensely studied over the past decades, mostly for their involvement in the multidrug resistance (MDR) phenotype. This review provides an overview of ABC transporters, both related and unrelated to MDR, which have been studied in osteosarcoma and Ewing's sarcoma. Since different backbone drugs used in first-line or rescue chemotherapy for these two rare bone sarcomas are substrates of ABC transporters, this review particularly focused on studies that have provided findings that have been either translated to clinical practice or have indicated new candidate therapeutic targets; however, findings obtained from ABC transporters that were not directly involved in drug resistance were also discussed, in order to provide a more complete overview of the biological impacts of these molecules in osteosarcoma and Ewing's sarcoma. Finally, therapeutic strategies and agents aimed to circumvent ABC-mediated chemoresistance were discussed to provide future perspectives about possible treatment improvements of these neoplasms.
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Affiliation(s)
- Massimo Serra
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
- Correspondence: ; Tel.: +39-051-6366762
| | - Claudia Maria Hattinger
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
| | - Michela Pasello
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
| | - Chiara Casotti
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
| | - Leonardo Fantoni
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
| | - Chiara Riganti
- Department of Oncology, University of Torino, Via Santena 5/bis, 10126 Torino, Italy;
| | - Maria Cristina Manara
- Laboratory of Experimental Oncology, IRCCS Istituto Ortopedico Rizzoli, Via di Barbiano 1/10, 40136 Bologna, Italy; (C.M.H.); (M.P.); (C.C.); (L.F.); (M.C.M.)
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10
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Wang H, Jiang Y. SRp20: A potential therapeutic target for human tumors. Pathol Res Pract 2021; 224:153444. [PMID: 34126370 DOI: 10.1016/j.prp.2021.153444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 04/11/2021] [Accepted: 04/11/2021] [Indexed: 12/12/2022]
Abstract
As an important member of SR protein family, SRp20 plays a crucial role in alternative splicing. It not only participates in cell cycle regulation, export of mRNA, cleaving of primary microRNAs, homologous recombination-mediated DNA repair, cellular senescence and apoptosis, but also gets involved in the integrity and pluripotency of genome. Alternative splicing maintains a strict balance in the body to ensure the normal physiological function of cells. Once the balance is broken, diseases, even tumors, will follow. Through the analysis of SRp20-related articles, we found that Alzheimer's disease, glaucoma, bipolar disorder and other diseases have a certain relationship with SRp20. More importantly, SRp20 is closely related to the occurrence, proliferation, invasion and metastasis of various tumors, as well as chemotherapy resistance. Some SRp20 inhibitors have shown significant anticancer efficacy, suggesting a potential therapeutic strategy for tumors.
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Affiliation(s)
- Han Wang
- Department of Pathology, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China
| | - Yanxia Jiang
- Department of Pathology, The Affiliated Hospital of Qingdao University, Qingdao, China.
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11
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Oh J, Pradella D, Shao C, Li H, Choi N, Ha J, Ruggiero S, Fu XD, Zheng X, Ghigna C, Shen H. Widespread Alternative Splicing Changes in Metastatic Breast Cancer Cells. Cells 2021; 10:cells10040858. [PMID: 33918758 PMCID: PMC8070448 DOI: 10.3390/cells10040858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/05/2021] [Accepted: 04/06/2021] [Indexed: 12/11/2022] Open
Abstract
Aberrant alternative splicing (AS) is a hallmark of cancer and a potential target for novel anti-cancer therapeutics. Breast cancer-associated AS events are known to be linked to disease progression, metastasis, and survival of breast cancer patients. To identify altered AS programs occurring in metastatic breast cancer, we perform a global analysis of AS events by using RNA-mediated oligonucleotide annealing, selection, and ligation coupled with next-generation sequencing (RASL-seq). We demonstrate that, relative to low-metastatic, high-metastatic breast cancer cells show different AS choices in genes related to cancer progression. Supporting a global reshape of cancer-related splicing profiles in metastatic breast cancer we found an enrichment of RNA-binding motifs recognized by several splicing regulators, which have aberrant expression levels or activity during breast cancer progression, including SRSF1. Among SRSF1-regulated targets we found DCUN1D5, a gene for which skipping of exon 4 in its pre-mRNA introduces a premature termination codon (PTC), thus generating an unstable transcript degraded by nonsense-mediated mRNA decay (NMD). Significantly, distinct breast cancer subtypes show different DCUN1D5 isoform ratios with metastatic breast cancer expressing the highest level of the NMD-insensitive DCUN1D5 mRNA, thus showing high DCUN1D5 expression levels, which are ultimately associated with poor overall and relapse-free survival in breast cancer patients. Collectively, our results reveal global AS features of metastatic breast tumors, which open new possibilities for the treatment of these aggressive tumor types.
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Affiliation(s)
- Jagyeong Oh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea; (J.O.); (N.C.); (J.H.); (X.Z.)
| | - Davide Pradella
- Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza”, National Research Council, Via Abbiategrasso 207, 27100 Pavia, Italy; (D.P.); (S.R.)
| | - Changwei Shao
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0021, USA; (C.S.); (H.L.); (X.-D.F.)
| | - Hairi Li
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0021, USA; (C.S.); (H.L.); (X.-D.F.)
| | - Namjeong Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea; (J.O.); (N.C.); (J.H.); (X.Z.)
| | - Jiyeon Ha
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea; (J.O.); (N.C.); (J.H.); (X.Z.)
| | - Sonia Ruggiero
- Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza”, National Research Council, Via Abbiategrasso 207, 27100 Pavia, Italy; (D.P.); (S.R.)
| | - Xiang-Dong Fu
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093-0021, USA; (C.S.); (H.L.); (X.-D.F.)
| | - Xuexiu Zheng
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea; (J.O.); (N.C.); (J.H.); (X.Z.)
| | - Claudia Ghigna
- Institute of Molecular Genetics “Luigi Luca Cavalli-Sforza”, National Research Council, Via Abbiategrasso 207, 27100 Pavia, Italy; (D.P.); (S.R.)
- Correspondence: (C.G.); (H.S.); Tel.: +39-0382-546324 (C.G.); +82-62-715-2507 (H.S.); Fax: +39-0382-422-286 (C.G.); +82-62-715-2484 (H.S.)
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Korea; (J.O.); (N.C.); (J.H.); (X.Z.)
- Correspondence: (C.G.); (H.S.); Tel.: +39-0382-546324 (C.G.); +82-62-715-2507 (H.S.); Fax: +39-0382-422-286 (C.G.); +82-62-715-2484 (H.S.)
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12
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Lin C, Yu B, Zhang M, Chen Y, Li L, Zhao D. Systematic Analyses of the Differentially Expressed Alternative Splicing Events in Gastric Cancer and Its Clinical Significance. Front Genet 2020; 11:522831. [PMID: 33281863 PMCID: PMC7705250 DOI: 10.3389/fgene.2020.522831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 09/10/2020] [Indexed: 12/29/2022] Open
Abstract
Accumulation of evidence has indicated a close relationship between alternative splicing (AS) and gastric cancer (GC), whereas systematic analyses of the differentially expressed AS events (DEAS) between GC and normal tissues are lacking. RNA-Seq data and the corresponding clinical information were downloaded from TCGA GC cohort. The percent spliced-in (PSI) value calculated in the GC tissues and normal tissues was employed to quantify the DEAS. Further, survival-associated DEAS and DEAS signatures were identified by univariate and multivariate cox regression analyses. To evaluate the association between DEAS and patients' clinical features, Kaplan-Meier analysis, receiver operator characteristic (ROC) curve, Cox proportional regression and nomograms incorporating the DEAS signatures were performed. DEAS and their splicing networks were finally analyzed by bioinformatics methods. In addition, we use the method of random grouping to divide the samples into the training group and the test group. The final results of the two groups are consistent. After strict filtering, a total of 44,935 AS events were identified, among which 11,141 DEAS were preliminarily screened from 5032 genes. A total of 454 DEAS was associated with OS, and 872 DEAS were associated with DFS. The final prognostic signatures were constructed from the survival-associated DEAS with an area under the receiver operating characteristic (ROC) curve (AUC) greater than 0.6. Only ES in ABI1 was simultaneously associated with OS and DFS. Finally, we identified the splicing correlation network between the prognostic splicing factors (SF) and DEAS in GC. Our study provided a systematic portrait of survival-associated DEAS in GC and uncovered splicing networks that are valuable in deciphering the underlying mechanisms of AS in GC.
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Affiliation(s)
- Changwei Lin
- School of Life Sciences, Central South University, Changsha, China.,Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Bowen Yu
- Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Mao Zhang
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yifei Chen
- Department of Otolaryngology-Head Neck Surgery, The Fourth Hospital of Changsha (The Changsha Affiliated Hospital of Hunan Normal University), Hunan Normal University, Changsha, China
| | - Liang Li
- Class 25 Grade 2016, The Five-Year Program in Clinical Medicine, School of Medicine, University of South China, Hengyang, China
| | - Deze Zhao
- Department of Thoracic Surgery, Xiangya Hospital, Central South University, Changsha, China
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13
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Pellarin I, Belletti B, Baldassarre G. RNA splicing alteration in the response to platinum chemotherapy in ovarian cancer: A possible biomarker and therapeutic target. Med Res Rev 2020; 41:586-615. [PMID: 33058230 DOI: 10.1002/med.21741] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/09/2020] [Accepted: 10/02/2020] [Indexed: 12/18/2022]
Abstract
Since its discovery, alternative splicing has been recognized as a powerful way for a cell to amplify the genetic information and for a living organism to adapt, evolve, and survive. We now know that a very high number of genes are regulated by alternative splicing and that alterations of splicing have been observed in different types of human diseases, including cancer. Here, we review the accumulating knowledge that links the regulation of alternative splicing to the response to chemotherapy, focusing our attention on ovarian cancer and platinum-based treatments. Moreover, we discuss how expanding information could be exploited to identify new possible biomarkers of platinum response, to better select patients, and/or to design new therapies able to overcome platinum resistance.
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Affiliation(s)
- Ilenia Pellarin
- Molecular Oncology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, National Cancer Institute, Aviano, Italy
| | - Barbara Belletti
- Molecular Oncology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, National Cancer Institute, Aviano, Italy
| | - Gustavo Baldassarre
- Molecular Oncology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, National Cancer Institute, Aviano, Italy
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14
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Zhou Z, Gong Q, Lin Z, Wang Y, Li M, Wang L, Ding H, Li P. Emerging Roles of SRSF3 as a Therapeutic Target for Cancer. Front Oncol 2020; 10:577636. [PMID: 33072610 PMCID: PMC7544984 DOI: 10.3389/fonc.2020.577636] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 08/28/2020] [Indexed: 12/14/2022] Open
Abstract
Ser/Arg-rich (SR) proteins are RNA-binding proteins known as constitutive and alternative splicing (AS) regulators that regulate multiple aspects of the gene expression program. Ser/Arg-rich splicing factor 3 (SRSF3) is the smallest member of the SR protein family, and its level is controlled by multiple factors and involves complex mechanisms in eukaryote cells, whereas the aberrant expression of SRSF3 is associated with many human diseases, including cancer. Here, we review state-of-the-art research on SRSF3 in terms of its function, expression, and misregulation in human cancers. We emphasize the negative consequences of the overexpression of the SRSF3 oncogene in cancers, the pathways underlying SRSF3-mediated transformation, and implications of potential anticancer drugs by downregulation of SRSF3 expression for cancer therapy. Cumulative research on SRSF3 provides critical insight into its essential part in maintaining cellular processes, offering potential new targets for anti-cancer therapy.
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Affiliation(s)
- Zhixia Zhou
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Qi Gong
- Departments of Pediatrics, Second Clinical Medical College of Qingdao University, Qingdao, China
| | - Zhijuan Lin
- Key Laboratory for Immunology in Universities of Shandong Province, School of Clinical Medicine, Weifang Medical University, Weifang, China
| | - Yin Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Mengkun Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lu Wang
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Hongfei Ding
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Peifeng Li
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
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15
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Fergany AAM, Tatarskiy VV. RNA Splicing: Basic Aspects Underlie Antitumor Targeting. Recent Pat Anticancer Drug Discov 2020; 15:293-305. [PMID: 32900350 DOI: 10.2174/1574892815666200908122402] [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: 03/31/2020] [Revised: 07/15/2020] [Accepted: 07/29/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND RNA splicing, a fundamental step in gene expression, is aimed at intron removal and ordering of exons to form the protein's reading frame. OBJECTIVE This review is focused on the role of RNA splicing in cancer biology; the splicing abnormalities that lead to tumor progression emerge as targets for therapeutic intervention. METHODS We discuss the role of aberrant mRNA splicing in carcinogenesis and drug response. RESULTS AND CONCLUSION Pharmacological modulation of RNA splicing sets the stage for treatment approaches in situations where mRNA splicing is a clinically meaningful mechanism of the disease.
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Affiliation(s)
- Alzahraa A M Fergany
- Department of Occupational and Environmental Health, Graduate School of Pharmaceutical Science, Tokyo University of Science, Chiba, Japan
| | - Victor V Tatarskiy
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, Russian Federation
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16
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More DA, Kumar A. SRSF3: Newly discovered functions and roles in human health and diseases. Eur J Cell Biol 2020; 99:151099. [PMID: 32800280 DOI: 10.1016/j.ejcb.2020.151099] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/15/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
The serine/arginine rich proteins (SR proteins) are members of a family of RNA binding proteins involved in regulating various features of RNA metabolism, including pre-mRNA constitutive and alternative splicing. In humans, a total of 12 SR splicing factors (SRSFs) namely SRSF1-SRSF12 have been reported. SRSF3, the smallest member of the SR family and the focus of this review, regulates critical steps in mRNA metabolism and has been shown to have mRNA-independent functions as well. Recent studies on SRSF3 have uncovered its role in a wide array of complex biological processes. We have also reviewed the involvement of SRSF3 in disease conditions like cancer, ageing, neurological and cardiac disorders. Finally, we have discussed in detail the autoregulation of SRSF3 and its implications in cancer and commented on the potential of SRSF3 as a therapeutic target, especially in the context of cancer.
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Affiliation(s)
- Dhanashree Anil More
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India
| | - Arun Kumar
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, 560012, India.
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17
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Shilpi A, Kandpal M, Ji Y, Seagle BL, Shahabi S, Davuluri RV. Platform-Independent Classification System to Predict Molecular Subtypes of High-Grade Serous Ovarian Carcinoma. JCO Clin Cancer Inform 2020; 3:1-9. [PMID: 31002564 PMCID: PMC6873993 DOI: 10.1200/cci.18.00096] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Molecular cancer subtyping is an important tool in predicting prognosis and developing novel precision medicine approaches. We developed a novel platform-independent gene expression-based classification system for molecular subtyping of patients with high-grade serous ovarian carcinoma (HGSOC). METHODS Unprocessed exon array (569 tumor and nine normal) and RNA sequencing (RNA-seq; 376 tumor) HGSOC data sets, with clinical annotations, were downloaded from the Genomic Data Commons portal. Sample clustering was performed by non-negative matrix factorization by using isoform-level expression estimates. The association between the subtypes and overall survival was evaluated by Cox proportional hazards regression model after adjusting for the covariates. A novel classification system was developed for HGSOC molecular subtyping. Robustness and generalizability of the gene signatures were validated using independent microarray and RNA-seq data sets. RESULTS Sample clustering recaptured the four known The Cancer Genome Atlas molecular subtypes but switched the subtype for 22% of the cases, which resulted in significant (P = .006) survival differences among the refined subgroups. After adjusting for covariate effects, the mesenchymal subgroup was found to be at an increased hazard for death compared with the immunoreactive subgroup. Both gene- and isoform-level signatures achieved more than 92% prediction accuracy when tested on independent samples profiled on the exon array platform. When the classifier was applied to RNA-seq data, the subtyping calls agreed with the predictions made from exon array data for 95% of the 279 samples profiled by both platforms. CONCLUSION Isoform-level expression analysis successfully stratifies patients with HGSOC into groups with differing prognosis and has led to the development of robust, platform-independent gene signatures for HGSOC molecular subtyping. The association of the refined The Cancer Genome Atlas HGSOC subtypes with overall survival, independent of covariates, enhances the clinical annotation of the HGSOC cohort.
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18
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Rahman MA, Nasrin F, Bhattacharjee S, Nandi S. Hallmarks of Splicing Defects in Cancer: Clinical Applications in the Era of Personalized Medicine. Cancers (Basel) 2020; 12:cancers12061381. [PMID: 32481522 PMCID: PMC7352608 DOI: 10.3390/cancers12061381] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/25/2020] [Accepted: 05/25/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing promotes proteome diversity by using limited number of genes, a key control point of gene expression. Splicing is carried out by large macromolecular machineries, called spliceosome, composed of small RNAs and proteins. Alternative splicing is regulated by splicing regulatory cis-elements in RNA and trans-acting splicing factors that are often tightly regulated in a tissue-specific and developmental stage-specific manner. The biogenesis of ribonucleoprotein (RNP) complexes is strictly regulated to ensure that correct complements of RNA and proteins are coordinated in the right cell at the right time to support physiological functions. Any perturbations that impair formation of functional spliceosomes by disrupting the cis-elements, or by compromising RNA-binding or function of trans-factors can be deleterious to cells and result in pathological consequences. The recent discovery of oncogenic mutations in splicing factors, and growing evidence of the perturbed splicing in multiple types of cancer, underscores RNA processing defects as a critical driver of oncogenesis. These findings have resulted in a growing interest in targeting RNA splicing as a therapeutic approach for cancer treatment. This review summarizes our current understanding of splicing alterations in cancer, recent therapeutic efforts targeting splicing defects in cancer, and future potentials to develop novel cancer therapies.
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19
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Zhou Y, Han C, Wang E, Lorch AH, Serafin V, Cho BK, Gutierrez Diaz BT, Calvo J, Fang C, Khodadadi-Jamayran A, Tabaglio T, Marier C, Kuchmiy A, Sun L, Yacu G, Filip SK, Jin Q, Takahashi YH, Amici DR, Rendleman EJ, Rawat R, Bresolin S, Paganin M, Zhang C, Li H, Kandela I, Politanska Y, Abdala-Valencia H, Mendillo ML, Zhu P, Palhais B, Van Vlierberghe P, Taghon T, Aifantis I, Goo YA, Guccione E, Heguy A, Tsirigos A, Wee KB, Mishra RK, Pflumio F, Accordi B, Basso G, Ntziachristos P. Posttranslational Regulation of the Exon Skipping Machinery Controls Aberrant Splicing in Leukemia. Cancer Discov 2020; 10:1388-1409. [PMID: 32444465 DOI: 10.1158/2159-8290.cd-19-1436] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 04/21/2020] [Accepted: 05/19/2020] [Indexed: 12/16/2022]
Abstract
Splicing alterations are common in diseases such as cancer, where mutations in splicing factor genes are frequently responsible for aberrant splicing. Here we present an alternative mechanism for splicing regulation in T-cell acute lymphoblastic leukemia (T-ALL) that involves posttranslational stabilization of the splicing machinery via deubiquitination. We demonstrate there are extensive exon skipping changes in disease, affecting proteasomal subunits, cell-cycle regulators, and the RNA machinery. We present that the serine/arginine-rich splicing factors (SRSF), controlling exon skipping, are critical for leukemia cell survival. The ubiquitin-specific peptidase 7 (USP7) regulates SRSF6 protein levels via active deubiquitination, and USP7 inhibition alters the exon skipping pattern and blocks T-ALL growth. The splicing inhibitor H3B-8800 affects splicing of proteasomal transcripts and proteasome activity and acts synergistically with proteasome inhibitors in inhibiting T-ALL growth. Our study provides the proof-of-principle for regulation of splicing factors via deubiquitination and suggests new therapeutic modalities in T-ALL. SIGNIFICANCE: Our study provides a new proof-of-principle for posttranslational regulation of splicing factors independently of mutations in aggressive T-cell leukemia. It further suggests a new drug combination of splicing and proteasomal inhibitors, a concept that might apply to other diseases with or without mutations affecting the splicing machinery.This article is highlighted in the In This Issue feature, p. 1241.
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Affiliation(s)
- Yalu Zhou
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Cuijuan Han
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Eric Wang
- Department of Pathology and Laura & Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, New York
| | - Adam H Lorch
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Valentina Serafin
- Oncohematology Laboratory, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Byoung-Kyu Cho
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois
| | - Blanca T Gutierrez Diaz
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Julien Calvo
- Team Niche and Cancer in hematopoiesis, CEA, Fontenay-aux-Roses, France.,Laboratory of Hematopoietic Stem Cells and Leukemia/Service Stem Cells and Radiation/iRCM/JACOB/DRF, CEA, Fontenay-aux-Roses, France
| | - Celestia Fang
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Alireza Khodadadi-Jamayran
- Applied Bioinformatics Laboratories, Office of Science and Research, New York University School of Medicine, New York, New York
| | - Tommaso Tabaglio
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Christian Marier
- Genome Technology Center, New York University School of Medicine, New York, New York
| | - Anna Kuchmiy
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium.,Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - Limin Sun
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - George Yacu
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Szymon K Filip
- Proteomics Center of Excellence, Northwestern University, Evanston, Illinois
| | - Qi Jin
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Yoh-Hei Takahashi
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - David R Amici
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Emily J Rendleman
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Radhika Rawat
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Medical Scientist Training Program, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Silvia Bresolin
- Oncohematology Laboratory, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Maddalena Paganin
- Oncohematology Laboratory, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Cheng Zhang
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Hu Li
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, Minnesota
| | - Irawati Kandela
- Center for Developmental Therapeutics, Northwestern University, Evanston, Illinois
| | - Yuliya Politanska
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Hiam Abdala-Valencia
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Marc L Mendillo
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Ping Zhu
- H3 Biomedicine, Inc., Cambridge, Massachusetts
| | - Bruno Palhais
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Pieter Van Vlierberghe
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium.,Department of Biomolecular Medicine, Ghent University, Ghent, Belgium
| | - Tom Taghon
- Cancer Research Institute Ghent (CRIG), Ghent, Belgium.,Department of Diagnostic Sciences, Ghent University, Ghent, Belgium.,Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium
| | - Iannis Aifantis
- Department of Pathology and Laura & Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, New York
| | - Young Ah Goo
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Proteomics Center of Excellence, Northwestern University, Evanston, Illinois
| | - Ernesto Guccione
- Department of Oncological Sciences and Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York.,Department of Pharmacological Sciences and Mount Sinai Center for Therapeutics Discovery, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Adriana Heguy
- Department of Pathology and Laura & Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, New York.,Genome Technology Center, New York University School of Medicine, New York, New York
| | - Aristotelis Tsirigos
- Department of Pathology and Laura & Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, New York.,Applied Bioinformatics Laboratories, Office of Science and Research, New York University School of Medicine, New York, New York
| | - Keng Boon Wee
- Applied Bioinformatics Laboratories, Office of Science and Research, New York University School of Medicine, New York, New York.,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Rama K Mishra
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois.,Center for Molecular Innovation and Drug Discovery, Northwestern University, Chicago, Illinois
| | - Francoise Pflumio
- Team Niche and Cancer in hematopoiesis, CEA, Fontenay-aux-Roses, France.,Laboratory of Hematopoietic Stem Cells and Leukemia/Service Stem Cells and Radiation/iRCM/JACOB/DRF, CEA, Fontenay-aux-Roses, France
| | - Benedetta Accordi
- Oncohematology Laboratory, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Giuseppe Basso
- Oncohematology Laboratory, Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Panagiotis Ntziachristos
- Department of Biochemistry and Molecular Genetics, Northwestern University, Chicago, Illinois. .,Simpson Querrey Institute for Epigenetics, Northwestern University Feinberg School of Medicine, Chicago, Illinois.,Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, Illinois
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20
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Sun T, Yang Q. Chemoresistance-associated alternative splicing signatures in serous ovarian cancer. Oncol Lett 2020; 20:420-430. [PMID: 32565967 DOI: 10.3892/ol.2020.11562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 02/21/2020] [Indexed: 12/17/2022] Open
Abstract
Primary platinum-based chemoresistance occurs in ~30% of patients with serous ovarian cancer. Chemoresistance is the main cause of disease recurrence, and accurate predictors to identify these patients with chemoresistance are required. Alternative splicing (AS) is a post-transcriptional modification process that is altered in cancer. A possible association between AS and chemoresistance is unclear and needs to be studied comprehensively in ovarian cancer. In the present study, RNA-sequencing data and clinical information for 320 patients with ovarian serous cystadenocarcinoma (OV) were downloaded from The Cancer Genome Atlas (TCGA) database. Splicing events were determined using the TCGA SpliceSeq tool. Seven types of AS events were identified. Univariate and multivariate logistic analyses were performed, and predictive models for OV chemoresistance were established, as well as a splicing network. A total of 22,036 AS events were identified in 7,404 genes, with 915 AS events detected in 677 genes that were significantly associated with chemoresistance in patients with OV. A receiver operating characteristic (ROC) curve was constructed for resistance predictive models composed of the most significant AS events. The area under the ROC curve was 0.931, indicating strong and efficient prediction of chemoresistance. Additionally, the high-risk score was associated with shorter overall survival. The splicing correlation network suggested a potential role of splicing factors in chemoresistance. In summary, the present study created a powerful predictor for primary platinum-based chemoresistance in patients with OV, identified splicing networks that could be involved in potential mechanisms of chemoresistance and provided potential targets to overcome chemoresistance.
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Affiliation(s)
- Tianshui Sun
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
| | - Qing Yang
- Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, P.R. China
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21
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Che Y, Fu L. Aberrant expression and regulatory network of splicing factor-SRSF3 in tumors. J Cancer 2020; 11:3502-3511. [PMID: 32284746 PMCID: PMC7150454 DOI: 10.7150/jca.42645] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/26/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing facilitates the splicing of precursor RNA into different isoforms. Alternatively spliced transcripts often exhibit antagonistic functions or differential temporal or spatial expression patterns. There is increasing evidence that alternative splicing, especially by the serine-arginine rich (SR) protein family, leads to abnormal expression patterns and is closely related to the development of cancer. SRSF3, also known as SRp20, is a splicing factor. Through alternative splicing, it plays important roles in regulating various biological functions, such as cell cycle, cell proliferation, migration and invasion, under pathological and physiological conditions. Deregulation of SRSF3 is an essential feature of cancers. SRSF3 is also considered a candidate therapeutic target. Therefore, the involvement of abnormal splicing in tumorigenesis and the regulation of splicing factors deserve further analysis and discussion. Here, we summarize the function of SRSF3-regulated alternative transcripts in cancer cell biology at different stages of tumor development and the regulation of SRSF3 in tumorigenesis.
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Affiliation(s)
- Yingying Che
- Institute of Chronic Disease, Qingdao Municipal Hospital, Qingdao University, Qingdao 266000, China
| | - Lin Fu
- Institute of Chronic Disease, Qingdao Municipal Hospital, Qingdao University, Qingdao 266000, China
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22
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Nobili S, Lapucci A, Landini I, Coronnello M, Roviello G, Mini E. Role of ATP-binding cassette transporters in cancer initiation and progression. Semin Cancer Biol 2020; 60:72-95. [PMID: 31412294 DOI: 10.1016/j.semcancer.2019.08.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/07/2019] [Accepted: 08/07/2019] [Indexed: 12/18/2022]
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23
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PTBP1-mediated regulation of AXL mRNA stability plays a role in lung tumorigenesis. Sci Rep 2019; 9:16922. [PMID: 31729427 PMCID: PMC6858377 DOI: 10.1038/s41598-019-53097-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 10/23/2019] [Indexed: 11/09/2022] Open
Abstract
AXL is expressed in many types of cancer and promotes cancer cell survival, metastasis and drug resistance. Here, we focus on identifying modulators that regulate AXL at the mRNA level. We have previously observed that the AXL promoter activity is inversely correlated with the AXL expression levels, suggesting that post-transcriptional mechanisms exist that down-regulate the expression of AXL mRNA. Here we show that the RNA binding protein PTBP1 (polypyrimidine tract-binding protein) directly targets the 5′-UTR of AXL mRNA in vitro and in vivo. Moreover, we also demonstrate that PTBP1, but not PTBP2, inhibits the expression of AXL mRNA and the RNA recognition motif 1 (RRM1) of PTBP1 is crucial for this interaction. To clarify how PTBP1 regulates AXL expression at the mRNA level, we found that, while the transcription rate of AXL was not significantly different, PTBP1 decreased the stability of AXL mRNA. In addition, over-expression of AXL may counteract the PTBP1-mediated apoptosis. Knock-down of PTBP1 expression could enhance tumor growth in animal models. Finally, PTBP1 was found to be negatively correlated with AXL expression in lung tumor tissues in Oncomine datasets and in tissue micro-array (TMA) analysis. In conclusion, we have identified a molecular mechanism of AXL expression regulation by PTBP1 through controlling the AXL mRNA stability. These findings may represent new thoughts alternative to current approaches that directly inhibit AXL signaling and may eventually help to develop novel therapeutics to avoid cancer metastasis and drug resistance.
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Li S, Shen L, Huang L, Lei S, Cai X, Breitzig M, Zhang B, Yang A, Ji W, Huang M, Zheng Q, Sun H, Wang F. PTBP1 enhances exon11a skipping in Mena pre-mRNA to promote migration and invasion in lung carcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:858-869. [PMID: 31075540 DOI: 10.1016/j.bbagrm.2019.04.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 04/16/2019] [Accepted: 04/18/2019] [Indexed: 12/13/2022]
Abstract
Alternative splicing (AS) events occur in the majority of human genes. AS in a single gene can give rise to different functions among multiple isoforms. Human ortholog of mammalian enabled (Mena) is a conserved regulator of actin dynamics that plays an important role in metastasis. Mena has been shown to have multiple splice variants in human tumor cells due to AS. However, the mechanism mediated Mena AS has not been elucidated. Here we showed that polypyrimidine tract-binding protein 1 (PTBP1) could modulate Mena AS. First, PTBP1 levels were elevated in metastatic lung cancer cells as well as during epithelial-mesenchymal transition (EMT) process. Then, knockdown of PTBP1 using shRNA inhibited migration and invasion of lung carcinoma cells and decreased the Mena exon11a skipping, whereas overexpression of PTBP1 had the opposite effects. The results of RNA pull-down assays and mutation analyses demonstrated that PTBP1 functionally targeted and physically interacted with polypyrimidine sequences on both upstream intron11 (TTTTCCCCTT) and downstream intron11a (TTTTTTTTTCTTT). In addition, the results of migration and invasion assays as well as detection of filopodia revealed that the effect of PTBP1 was reversed by knockdown of Mena but not Mena11a+. Overexpressed MenaΔ11a also rescued the PTBP1-induced migration and invasion. Taken together, our study provides a novel mechanism that PTBP1 modulates Mena exon11a skipping, and indicates that PTBP1 depends on the level of Mena11a- to promote lung cancer cells migration and invasion. The regulation of Mena AS may be a potential prognostic marker and a promising target for treatment of lung carcinoma.
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Affiliation(s)
- Shuaiguang Li
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Lianghua Shen
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Luyuan Huang
- Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Key Laboratory of Regenerative Biology, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Sijia Lei
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Xingdong Cai
- Department of Respiratory, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China
| | - Mason Breitzig
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, MDC 19, Tampa, FL 33612, USA
| | - Bin Zhang
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Annan Yang
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Wenzuo Ji
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Meiyan Huang
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Qing Zheng
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Hanxiao Sun
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China
| | - Feng Wang
- Institute of Genomic Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, China; Guangdong Provincial Key Laboratory of Pharmacodynamics Constituents of TCM and New Drugs Research, Jinan University, Guangzhou 510632, China; International Cooperative Laboratory of Traditional Chinese Medicine Modernization and Innovative Drug Development of Chinese Ministry of Education (MOE), College of pharmacy, Jinan University, Guangzhou 510632, China.
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25
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Wang BD, Lee NH. Aberrant RNA Splicing in Cancer and Drug Resistance. Cancers (Basel) 2018; 10:E458. [PMID: 30463359 PMCID: PMC6266310 DOI: 10.3390/cancers10110458] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 12/22/2022] Open
Abstract
More than 95% of the 20,000 to 25,000 transcribed human genes undergo alternative RNA splicing, which increases the diversity of the proteome. Isoforms derived from the same gene can have distinct and, in some cases, opposing functions. Accumulating evidence suggests that aberrant RNA splicing is a common and driving event in cancer development and progression. Moreover, aberrant splicing events conferring drug/therapy resistance in cancer is far more common than previously envisioned. In this review, aberrant splicing events in cancer-associated genes, namely BCL2L1, FAS, HRAS, CD44, Cyclin D1, CASP2, TMPRSS2-ERG, FGFR2, VEGF, AR and KLF6, will be discussed. Also highlighted are the functional consequences of aberrant splice variants (BCR-Abl35INS, BIM-γ, IK6, p61 BRAF V600E, CD19-∆2, AR-V7 and PIK3CD-S) in promoting resistance to cancer targeted therapy or immunotherapy. To overcome drug resistance, we discuss opportunities for developing novel strategies to specifically target the aberrant splice variants or splicing machinery that generates the splice variants. Therapeutic approaches include the development of splice variant-specific siRNAs, splice switching antisense oligonucleotides, and small molecule inhibitors targeting splicing factors, splicing factor kinases or the aberrant oncogenic protein isoforms.
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Affiliation(s)
- Bi-Dar Wang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Eastern Shore, Princess Anne, MD 21853, USA.
| | - Norman H Lee
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, GW Cancer Center, Washington, DC 20037, USA.
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26
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Li X, Han F, Liu W, Shi X. PTBP1 promotes tumorigenesis by regulating apoptosis and cell cycle in colon cancer. Bull Cancer 2018; 105:1193-1201. [PMID: 30309622 DOI: 10.1016/j.bulcan.2018.08.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 08/07/2018] [Accepted: 08/10/2018] [Indexed: 10/28/2022]
Abstract
Increased expression of polypyrimidine tract-binding protein 1 (PTBP1) has been observed in human ovarian tumors, glioblastomas, and breast cancer, but its biological roles in tumorigenesis is not fully clear. In the present research, we investigated the biological role of PTBP1 in colon cancer. We found that PTBP1 was overexpressed both in colon cancer cell lines and tissues. Tissue microarray analysis (TMA) indicated that low PTBP1 expression predicted a favorable overall survival for colon cancer patients. Using small interfering RNA technology, we found that down-regulation of PTBP1 significantly inhibited colon cancer cell growth/proliferation, and induced cell cycle arrest as well as apoptosis in vitro. Western blot analysis showed that siRNA PTBP1 could up-regulate the expression of cytoC, p53 and Bax as well as down-regulated p85, p-AKT, cyclinD1, CDK4 and Bcl2 compared to the control. Furthermore, Caspase-3 and PARP1 were activated when PTBP1 is knockdown. This study implies that PTBP1 plays an important role in tumorigenesis of colon cancer.
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Affiliation(s)
- Xiaona Li
- Xinxiang Second People's Hospital, Department of Pharmacy, Xinxiang, PR China
| | - Fei Han
- Army Medical University, College of Preventive Medicine, Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education of China, Institute of Toxicology, Chongqing, China
| | - Wenbin Liu
- Army Medical University, College of Preventive Medicine, Key Laboratory of Medical Protection for Electromagnetic Radiation, Ministry of Education of China, Institute of Toxicology, Chongqing, China
| | - Xiaoyan Shi
- Henan University, Institute of Chinese materia medica, Kaifeng, China.
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27
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Urbanski L, Leclair N, Anczuków O. Alternative-splicing defects in cancer: Splicing regulators and their downstream targets, guiding the way to novel cancer therapeutics. WILEY INTERDISCIPLINARY REVIEWS. RNA 2018; 9:e1476. [PMID: 29693319 PMCID: PMC6002934 DOI: 10.1002/wrna.1476] [Citation(s) in RCA: 229] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 02/27/2018] [Accepted: 03/01/2018] [Indexed: 12/14/2022]
Abstract
Defects in alternative splicing are frequently found in human tumors and result either from mutations in splicing-regulatory elements of specific cancer genes or from changes in the regulatory splicing machinery. RNA splicing regulators have emerged as a new class of oncoproteins and tumor suppressors, and contribute to disease progression by modulating RNA isoforms involved in the hallmark cancer pathways. Thus, dysregulation of alternative RNA splicing is fundamental to cancer and provides a potentially rich source of novel therapeutic targets. Here, we review the alterations in splicing regulatory factors detected in human tumors, as well as the resulting alternatively spliced isoforms that impact cancer hallmarks, and discuss how they contribute to disease pathogenesis. RNA splicing is a highly regulated process and, as such, the regulators are themselves tightly regulated. Differential transcriptional and posttranscriptional regulation of splicing factors modulates their levels and activities in tumor cells. Furthermore, the composition of the tumor microenvironment can also influence which isoforms are expressed in a given cell type and impact drug responses. Finally, we summarize current efforts in targeting alternative splicing, including global splicing inhibition using small molecules blocking the spliceosome or splicing-factor-modifying enzymes, as well as splice-switching RNA-based therapeutics to modulate cancer-specific splicing isoforms. This article is categorized under: RNA in Disease and Development > RNA in Disease RNA Processing > Splicing Regulation/Alternative Splicing.
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28
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El-Athman R, Fuhr L, Relógio A. A Systems-Level Analysis Reveals Circadian Regulation of Splicing in Colorectal Cancer. EBioMedicine 2018; 33:68-81. [PMID: 29936137 PMCID: PMC6085510 DOI: 10.1016/j.ebiom.2018.06.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/28/2018] [Accepted: 06/11/2018] [Indexed: 12/26/2022] Open
Abstract
Accumulating evidence points to a significant role of the circadian clock in the regulation of splicing in various organisms, including mammals. Both dysregulated circadian rhythms and aberrant pre-mRNA splicing are frequently implicated in human disease, in particular in cancer. To investigate the role of the circadian clock in the regulation of splicing in a cancer progression context at the systems-level, we conducted a genome-wide analysis and compared the rhythmic transcriptional profiles of colon carcinoma cell lines SW480 and SW620, derived from primary and metastatic sites of the same patient, respectively. We identified spliceosome components and splicing factors with cell-specific circadian expression patterns including SRSF1, HNRNPLL, ESRP1, and RBM 8A, as well as altered alternative splicing events and circadian alternative splicing patterns of output genes (e.g., VEGFA, NCAM1, FGFR2, CD44) in our cellular model. Our data reveals a remarkable interplay between the circadian clock and pre-mRNA splicing with putative consequences in tumor progression and metastasis.
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Affiliation(s)
- Rukeia El-Athman
- Institute for Theoretical Biology (ITB), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany; Medical Department of Hematology, Oncology, and Tumor Immunology, Molekulares Krebsforschungszentrum (MKFZ), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany
| | - Luise Fuhr
- Institute for Theoretical Biology (ITB), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany; Medical Department of Hematology, Oncology, and Tumor Immunology, Molekulares Krebsforschungszentrum (MKFZ), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany
| | - Angela Relógio
- Institute for Theoretical Biology (ITB), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany; Medical Department of Hematology, Oncology, and Tumor Immunology, Molekulares Krebsforschungszentrum (MKFZ), Charité - Universitätsmedizin Berlin, Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin Institute of Health, Germany.
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29
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Wang X, Li Y, Fan Y, Yu X, Mao X, Jin F. PTBP1 promotes the growth of breast cancer cells through the PTEN/Akt pathway and autophagy. J Cell Physiol 2018; 233:8930-8939. [PMID: 29856478 PMCID: PMC6175200 DOI: 10.1002/jcp.26823] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 04/30/2018] [Indexed: 12/22/2022]
Abstract
Invasion and migration is the hallmark of malignant tumors as well as the major cause for breast cancer death. The polypyrimidine tract binding, PTB, protein serves as an important model for understanding how RNA binding proteins affect proliferation and invasion and how changes in the expression of these proteins can control complex programs of tumorigenesis. We have investigated some roles of polypyrimidine tract binding protein 1 (PTBP1) in human breast cancer. We found that PTBP1 was upregulated in breast cancer tissues compared with normal tissues and the same result was confirmed in breast cancer cell lines. Knockdown of PTBP1 substantially inhibited tumor cell growth, migration, and invasion. These results suggest that PTBP1 is associated with breast tumorigenesis and appears to be required for tumor cell growth and maintenance of metastasis. We further analyzed the relationship between PTBP1 and clinicopathological parameters and found that PTBP1 was correlated with her‐2 expression, lymph node metastasis, and pathological stage. This will be a novel target for her‐2(+) breast cancer. PTBP1 exerts these effects, in part, by regulating the phosphatase and tensin homolog‐phosphatidylinositol‐4,5‐bisphosphate 3‐kinase/protein kinase B (PTEN‐PI3K/Akt) pathway and autophagy, and consequently alters cell growth and contributes to the invasion and metastasis.
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Affiliation(s)
- Xu Wang
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang City, Liaoning, China
| | - Yang Li
- Department of Cell Biology, Key Laboratory of Cell Biology, Ministry of Public Health, and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China
| | - Yan Fan
- Department of Pediatrics, The First Affiliated Hospital of China Medical University, Shenyang City, Liaoning, China
| | - Xinmiao Yu
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang City, Liaoning, China
| | - Xiaoyun Mao
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang City, Liaoning, China
| | - Feng Jin
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang City, Liaoning, China
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30
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Wang ZN, Liu D, Yin B, Ju WY, Qiu HZ, Xiao Y, Chen YJ, Peng XZ, Lu CM. High expression of PTBP1 promote invasion of colorectal cancer by alternative splicing of cortactin. Oncotarget 2018; 8:36185-36202. [PMID: 28404950 PMCID: PMC5482648 DOI: 10.18632/oncotarget.15873] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 01/23/2017] [Indexed: 12/22/2022] Open
Abstract
Polypyrimidine tract-binding protein 1 (PTBP1) involving in almost all steps of mRNA regulation including alternative splicing metabolism during tumorigenesis due to its RNA-binding activity. Initially, we found that high expressed PTBP1 and poor prognosis was interrelated in colorectal cancer (CRC) patients with stages II and III CRC, which widely different in prognosis and treatment, by immunohistochemistry. PTBP1 was also upregulated in colon cancer cell lines. In our study, knockdown of PTBP1 by siRNA transfection decreased cell proliferation and invasion in vitro. Denovirus shRNA knockdown of PTBP1 inhibited colorectal cancer growth in vivo. Furthermore, PTBP1 regulates alternative splicing of many target genes involving in tumorgenesis in colon cancer cells. We confirmed that the splicing of cortactin exon 11 which was only contained in cortactin isoform-a, as a PTBP1 target. Knockdown of PTBP1 decreased the expression of cortactin isoform-a by exclusion of exon 11. Also the mRNA levels of PTBP1 and cortactin isoform-a were cooperatively expressed in colorectal cancer tissues. Knocking down cortactin isoform-a significantly decreased cell migration and invasion in colorectal cancer cells. Overexpression of cortactin isoform-a could rescue PTBP1-knockdown effect of cell motility. In summary the study revealed that PTBP1 facilitates colorectal cancer migration and invasion activities by inclusion of cortactin exon 11.
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Affiliation(s)
- Zhi-Na Wang
- Department of Gastroenteology and Hepatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Dan Liu
- Department of Gastroenteology and Hepatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.,Department of Gastroenterology and Hepatology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Bin Yin
- National Laboratory of Meidical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Wen-Yi Ju
- National Laboratory of Meidical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Zhong Qiu
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yi Xiao
- Department of General Surgery, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuan-Jia Chen
- Department of Gastroenteology and Hepatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| | - Xiao-Zhong Peng
- National Laboratory of Meidical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Chong-Mei Lu
- Department of Gastroenteology and Hepatology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
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31
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Marques DS, Grativol J, Alves da Silva Peres R, da Rocha Matos A, Gimba ERP. Osteopontin-c isoform levels are associated with SR and hnRNP differential expression in ovarian cancer cell lines. Tumour Biol 2017; 39:1010428317725442. [PMID: 28936921 DOI: 10.1177/1010428317725442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Osteopontin-c splicing isoform activates ovarian cancer progression features. Imbalanced expression of splicing factors from serine/arginine -rich and heterogeneous ribonucleoproteins families has been correlated with the generation of oncogenic splicing isoforms. Our goal was to investigate whether there is any association between the transcriptional patterns of these splicing factors in ovarian cells and osteopontin-c expression levels. We also aimed to investigate the occurrence of these splicing factors binding sites inside osteopontin exon 4 and adjacent introns. To test associations between osteopontin-c and splicing factors expression patterns, we used an in vitro model in which OVCAR-3 cells overexpressing osteopontin-c (OVCAR-3/OPNc++) presented higher transcriptional levels of osteopontin-c than two other ovarian carcinoma cells (TOV-112D, SKOV-3) and ovarian non-tumoral cell lines (IOSE 364 and IOSE 385). The transcriptional levels of osteopontin-c, serine/arginine-rich, and hnRNP factors were evaluated using real-time polymerase chain reaction. Human Splice Finder software was used to search for putative splicing factor binding sites in osteopontin genomic regions. OVCAR-3/OPNc++ cells presented higher transcriptional levels of hnRNP than serine/arginine-rich when compared to TOV-112D, SKOV-3, and IOSE cells. TOV-112D and SKOV-3 cells also overexpressed hnRNP in relation to serine/arginine-rich transcripts. Putative binding sites for these splicing factors have been predicted on osteopontin exon 4 and their upstream and downstream intronic regions. Our data showed that higher osteopontin-c expression levels are associated with a predominance of hnRNP in relation to serine/arginine-rich transcripts and that osteopontin exon 4 and adjacent intronic sequences contain predicted binding sites for some of these tested splicing factors. In conclusion, differential expression of these splicing factors in ovarian cancer cells could be one of the putative mechanisms leading to aberrant splicing of the osteopontin primary transcript. Future work, aiming to control ovarian cancer progression by downregulating osteopontin-c levels, could include strategies that also regulate heterogeneous ribonucleoproteins and serine/arginine-rich expression levels in order to modulate osteopontin splicing.
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Affiliation(s)
- Durval Santos Marques
- 1 Programa de Pós Graduação em Ciências Biomédicas (Fisiologia e Farmacologia), Universidade Federal Fluminense, Rio de Janeiro, Brazil
| | - Jessica Grativol
- 2 Curso de Graduação em Enfermagem, Universidade Federal Fluminense, Rio de Janeiro, Brazil
| | | | - Aline da Rocha Matos
- 3 Laboratório de Vírus Respiratórios e do Sarampo, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil
| | - Etel Rodrigues Pereira Gimba
- 4 Departamento de Ciências da Natureza (RCN), Instituto de Humanidades e Saúde (IHS), Universidade Federal Fluminense, Rio de Janeiro, Brazil.,5 Coordenação de Pesquisa, Programa de Pós Graduação Stricto Sensu em Oncologia do INCa, Instituto Nacional de Câncer (INCa), Rio de Janeiro, Brazil
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32
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Sheng J, Zhao J, Xu Q, Wang L, Zhang W, Zhang Y. Bioinformatics analysis of SRSF1-controlled gene networks in colorectal cancer. Oncol Lett 2017; 14:5393-5399. [PMID: 29113173 PMCID: PMC5656040 DOI: 10.3892/ol.2017.6900] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/15/2017] [Indexed: 12/13/2022] Open
Abstract
Colorectal cancer is the third most common type of cancer and the fourth leading cause of cancer-associated mortality worldwide. Serine/arginine-rich splicing factor 1 (SRSF1) is a well-characterized oncogenic factor that promotes tumorigenesis by controlling a number of alternative splicing events. However, there is limited network analysis, from a global aspect, to study the effect of SRSF1 on colorectal cancer. In the present study, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of available gene regulation data from The Cancer Genome Atlas database revealed the enriched functions and signaling pathways of SRSF1. Subsequently, Oncomine analysis was performed, which demonstrated that SRSF1 was upregulated in a number of types of colon cancer. From overlapping the analysis of 2,678 SRSF1-related genes and 3,625 colorectal cancer genes in GeneCards, 468 genes were identified as SRSF1-related colorectal cancer genes. The GO results revealed that these overlapped genes were primarily enriched in metabolic processes, response to DNA damage, regulation of the cell cycle and a number of additional biological processes. KEGG pathway analysis revealed that SRSF1-related colorectal cancer genes were associated with the cell cycle, deregulated signaling pathways associated with cancer progression and colorectal cancer signaling pathways. In addition, the Search Tool for the Retrieval of Interacting Genes/Proteins database and Cytoscape analysis demonstrated that 468 SRSF1-related colorectal cancer genes exhibit potential interaction networks in which these genes were enriched in DNA metabolic processes, cell cycle regulation and regulation of apoptosis. The results of the present study suggested that SRSF1 exhibited an increased degree of interaction with key molecules, including NUF2 NDC80 kinetochore complex component, kinesin family member 2C, structural maintenance of chromosomes 3, ATM serine/threonine kinase, BRCA1 DNA repair associated, protein kinase DNA-activated catalytic polypeptide, heat shock protein 90 alpha family class A member 1, ras homolog family member A, and phosphatase and tensin homolog. Collectively, the bioinformatics analysis of the present study indicated that SRSF1 may have key functions in the progression and development of colorectal cancer.
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Affiliation(s)
- Junxiu Sheng
- Department of Oncology, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China.,Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Jinyao Zhao
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Qiuhong Xu
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Linlin Wang
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Wenjing Zhang
- Institute of Cancer Stem Cell, Cancer Center, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Yang Zhang
- Department of Oncology, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
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Kozlovski I, Siegfried Z, Amar-Schwartz A, Karni R. The role of RNA alternative splicing in regulating cancer metabolism. Hum Genet 2017; 136:1113-1127. [PMID: 28429085 DOI: 10.1007/s00439-017-1803-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
Abstract
Tumor cells alter their metabolism by a wide array of mechanisms to promote growth and proliferation. Dysregulated expression and/or somatic mutations of key components of the glycolytic pathway/TCA cycle as well as other metabolic pathways allow tumor cells to improve their ability to survive harsh conditions such as hypoxia and the presence of reactive oxygen species, as well as the ability to obtain nutrients to increase lipids, protein, and nucleic acids biogenesis. Approximately 95% of the human protein encoding genes undergo alternative splicing (AS), a regulated process of gene expression that greatly diversifies the proteome by creating multiple proteins from a single gene. In recent years, a growing body of evidence suggests that unbalanced AS, the formation of certain pro-tumorigenic isoforms and the reduction of anti-tumorigenic isoforms, is implicated in a variety of cancers. It is becoming increasingly clear that cancer-associated AS contributes to increased growth and proliferation, partially due to effects on metabolic reprogramming. Here, we summarize the known roles of AS in regulating cancer metabolism. We present evidence supporting the idea that AS, in many types of cancer, acts as a molecular switch that alters metabolism to drive tumorigenesis. We propose that the elucidation of misregulated AS and its downstream effects on cancer metabolism emphasizes the need for new therapeutic approaches aiming to modulate the splicing machinery to selectively target cancer cells.
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Affiliation(s)
- Itamar Kozlovski
- Department of Biochemistry and Molecular Biology, IMRIC, Hebrew University-Hadassah Medical School, Ein Karem, 91120, Jerusalem, Israel
| | - Zahava Siegfried
- Department of Biochemistry and Molecular Biology, IMRIC, Hebrew University-Hadassah Medical School, Ein Karem, 91120, Jerusalem, Israel
| | - Adi Amar-Schwartz
- Department of Biochemistry and Molecular Biology, IMRIC, Hebrew University-Hadassah Medical School, Ein Karem, 91120, Jerusalem, Israel
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology, IMRIC, Hebrew University-Hadassah Medical School, Ein Karem, 91120, Jerusalem, Israel.
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Abstract
Tumor-associated alterations in RNA splicing result either from mutations in splicing-regulatory elements or changes in components of the splicing machinery. This review summarizes our current understanding of the role of splicing-factor alterations in human cancers. We describe splicing-factor alterations detected in human tumors and the resulting changes in splicing, highlighting cell-type-specific similarities and differences. We review the mechanisms of splicing-factor regulation in normal and cancer cells. Finally, we summarize recent efforts to develop novel cancer therapies, based on targeting either the oncogenic splicing events or their upstream splicing regulators.
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Affiliation(s)
- Olga Anczuków
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Adrian R Krainer
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
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Gökirmak T, Campanale JP, Reitzel AM, Shipp LE, Moy GW, Hamdoun A. Functional diversification of sea urchin ABCC1 (MRP1) by alternative splicing. Am J Physiol Cell Physiol 2016; 310:C911-20. [PMID: 27053522 DOI: 10.1152/ajpcell.00029.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 04/01/2016] [Indexed: 11/22/2022]
Abstract
The multidrug resistance protein (MRP) family encodes a diverse repertoire of ATP-binding cassette (ABC) transporters with multiple roles in development, disease, and homeostasis. Understanding MRP evolution is central to unraveling their roles in these diverse processes. Sea urchins occupy an important phylogenetic position for understanding the evolution of vertebrate proteins and have been an important invertebrate model system for study of ABC transporters. We used phylogenetic analyses to examine the evolution of MRP transporters and functional approaches to identify functional forms of sea urchin MRP1 (also known as SpABCC1). SpABCC1, the only MRP homolog in sea urchins, is co-orthologous to human MRP1, MRP3, and MRP6 (ABCC1, ABCC3, and ABCC6) transporters. However, efflux assays revealed that alternative splicing of exon 22, a region critical for substrate interactions, could diversify functions of sea urchin MRP1. Phylogenetic comparisons also indicate that while MRP1, MRP3, and MRP6 transporters potentially arose from a single transporter in basal deuterostomes, alternative splicing appears to have been the major mode of functional diversification in invertebrates, while duplication may have served a more important role in vertebrates. These results provide a deeper understanding of the evolutionary origins of MRP transporters and the potential mechanisms used to diversify their functions in different groups of animals.
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Affiliation(s)
- Tufan Gökirmak
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California; and
| | - Joseph P Campanale
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California; and
| | - Adam M Reitzel
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, North Carolina
| | - Lauren E Shipp
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California; and
| | - Gary W Moy
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California; and
| | - Amro Hamdoun
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California; and
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Cai BL, Li Y, Shen LL, Zhao JL, Liu Y, Wu JZ, Liu YP, Yu B. Nuclear Multidrug Resistance-Related Protein 1 Is Highly Associated with Better Prognosis of Human Mucoepidermoid Carcinoma through the Suppression of Cell Proliferation, Migration and Invasion. PLoS One 2016; 11:e0148223. [PMID: 26829120 PMCID: PMC4734599 DOI: 10.1371/journal.pone.0148223] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Accepted: 01/14/2016] [Indexed: 11/18/2022] Open
Abstract
Objectives Multidrug resistance-related protein 1 (MRP1) overexpression is a well acknowledged predictor of poor response to chemotherapy, but MRP1 also correlated to better prognosis in some reports, especially for patients not pretreated with chemotherapy. In our previous study, we found nuclear translocation of MRP1 in mucoepidermoid carcinoma (MEC) for the first time. The purpose of this study was to further investigate the function of nuclear MRP1 in MEC. Materials and Methods Human MEC tissue samples of 125 patients were selected and stained using immunohistochemistry. The expression level of total MRP1/nuclear MRP1 of each sample was evaluated by expression index (EI) which was scored using both qualitative and quantitative analysis. The correlations between the clinicopathologic parameters and the EI of nuclear MRP1 were analyzed using Spearman’s rank correlation analysis, respectively. The effects of RNAi-mediated downregulation of nuclear MRP1 on MEC cells were assessed using flow cytometric analysis, MTT assay, plate colony formation assay, transwell invasion assay and monolayer wound healing assay. Results In this study, we found the EI of nuclear MRP1 was negatively correlated to the pathologic grading (r = -0.498, P<0.01) / clinical staging (r = -0.41, P<0.01) / tumor stage (r = -0.28, P = 0.02) / nodal stage (r = -0.29, P<0.01) of MEC patients. The RNAi-mediated downregulation of nuclear MRP1 further proved that the downregulation of nuclear MRP1 could increase the cell replication, growth speed, colony formation efficiency, migration and invasion ability of MEC cells. Conclusion Our results suggested that nuclear MRP1 is highly associated with better prognosis of human mucoepidermoid carcinoma and further study of its function mechanism would provide clues in developing new treatment modalities of MEC.
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Affiliation(s)
- Bo-Lei Cai
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
| | - Yan Li
- State Key Laboratory of Military Stomatology, Department of Prosthodontics, School of Stomatology, the Fourth Military Medical University, Xi'an 710032, People's Republic of China
| | - Liang-Liang Shen
- The State Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
| | - Jin-Long Zhao
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
| | - Yuan Liu
- State Key Laboratory of Military Stomatology, Department of Oral Histology and Pathology, School of Stomatology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
| | - Jun-Zheng Wu
- State Key Laboratory of Military Stomatology, Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Chang Le Xi Road, Xi’an 710032, People's Republic of China
| | - Yan-Pu Liu
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
- * E-mail: (BY); (YPL)
| | - Bo Yu
- State Key Laboratory of Military Stomatology, Department of Oral and Maxillofacial Surgery, School of Stomatology, the Fourth Military Medical University, Xi’an 710032, People's Republic of China
- * E-mail: (BY); (YPL)
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Ajiro M, Jia R, Yang Y, Zhu J, Zheng ZM. A genome landscape of SRSF3-regulated splicing events and gene expression in human osteosarcoma U2OS cells. Nucleic Acids Res 2015; 44:1854-70. [PMID: 26704980 PMCID: PMC4770227 DOI: 10.1093/nar/gkv1500] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
Alternative RNA splicing is an essential process to yield proteomic diversity in eukaryotic cells, and aberrant splicing is often associated with numerous human diseases and cancers. We recently described serine/arginine-rich splicing factor 3 (SRSF3 or SRp20) being a proto-oncogene. However, the SRSF3-regulated splicing events responsible for its oncogenic activities remain largely unknown. By global profiling of the SRSF3-regulated splicing events in human osteosarcoma U2OS cells, we found that SRSF3 regulates the expression of 60 genes including ERRFI1, ANXA1 and TGFB2, and 182 splicing events in 164 genes, including EP300, PUS3, CLINT1, PKP4, KIF23, CHK1, SMC2, CKLF, MAP4, MBNL1, MELK, DDX5, PABPC1, MAP4K4, Sp1 and SRSF1, which are primarily associated with cell proliferation or cell cycle. Two SRSF3-binding motifs, CCAGC(G)C and A(G)CAGCA, are enriched to the alternative exons. An SRSF3-binding site in the EP300 exon 14 is essential for exon 14 inclusion. We found that the expression of SRSF1 and SRSF3 are mutually dependent and coexpressed in normal and tumor tissues/cells. SRSF3 also significantly regulates the expression of at least 20 miRNAs, including a subset of oncogenic or tumor suppressive miRNAs. These data indicate that SRSF3 affects a global change of gene expression to maintain cell homeostasis.
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Affiliation(s)
- Masahiko Ajiro
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Rong Jia
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Yanqin Yang
- DNA Sequencing and Genomics Core, System Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jun Zhu
- DNA Sequencing and Genomics Core, System Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zhi-Ming Zheng
- Tumor Virus RNA Biology Section, Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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He X, Zhang P. Serine/arginine-rich splicing factor 3 (SRSF3) regulates homologous recombination-mediated DNA repair. Mol Cancer 2015; 14:158. [PMID: 26282282 PMCID: PMC4539922 DOI: 10.1186/s12943-015-0422-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 07/28/2015] [Indexed: 12/20/2022] Open
Abstract
Background Our previous work found that serine/arginine-rich splicing factor 3 (SRSF3) was overexpressed in human ovarian cancer and the overexpression of SRSF3 was required for ovarian cancer cell growth and survival. The mechanism underlying the role of SRSF3 in ovarian cancer remains to be addressed. Methods We conducted microarray analysis to profile the gene expression and splicing in SRSF3-knockdown cells and employed quantitative PCR and western blotting to validate the profiling results. We used chromatin immunoprecipitation to study transcription and the direct repeat green fluorescent protein reporter assay to study homologous recombination-mediated DNA repair (HRR). Results We identified 687 genes with altered expression and 807 genes with altered splicing in SRSF3-knockdown cells. Among expression-altered genes, those involved in HRR, including BRCA1, BRIP1 and RAD51, were enriched and were all downregulated. We demonstrated that the downregulation of BRCA1, BRIP1 and RAD51 expression was caused by decreased transcription and not due to increased nonsense-mediated mRNA decay. Further, we found that SRSF3 knockdown impaired HRR activity in the cell and increased the level of γ-H2AX, a biomarker for double-strand DNA breaks. Finally, we observed that SRSF3 knockdown changed splicing pattern of KMT2C, a H3K4-specific histone methyltransferase, and reduced the levels of mono- and trimethylated H3K4. Conclusion These results suggest that SRSF3 is a new regulator of HRR process, which possibly regulates the expression of HRR-related genes indirectly through an epigenetic pathway. This new function of SRSF3 not only explains why overexpression of SRSF3 is required for ovarian cancer cell growth and survival but also offers a new insight into the mechanism of the neoplastic transformation. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0422-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiaolong He
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago-Rockford Campus, 1601 Parkview Avenue, Room N308, Rockford, IL, 61107, USA. .,University of Illinois Cancer Center, University of Illinois at Chicago, Chicago, IL, USA.
| | - Pei Zhang
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago-Rockford Campus, 1601 Parkview Avenue, Room N308, Rockford, IL, 61107, USA.
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Endsley MP, Moyle-Heyrman G, Karthikeyan S, Lantvit DD, Davis DA, Wei JJ, Burdette JE. Spontaneous Transformation of Murine Oviductal Epithelial Cells: A Model System to Investigate the Onset of Fallopian-Derived Tumors. Front Oncol 2015; 5:154. [PMID: 26236688 PMCID: PMC4505108 DOI: 10.3389/fonc.2015.00154] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 06/29/2015] [Indexed: 12/20/2022] Open
Abstract
High-grade serous carcinoma (HGSC) is the most lethal ovarian cancer histotype. The fallopian tube secretory epithelial cells (FTSECs) are a proposed progenitor cell type. Genetically altered FTSECs form tumors in mice; however, a spontaneous HGSC model has not been described. Apart from a subpopulation of genetically predisposed women, most women develop ovarian cancer spontaneously, which is associated with aging and lifetime ovulations. A murine oviductal cell line (MOE(LOW)) was developed and continuously passaged in culture to mimic cellular aging (MOE(HIGH)). The MOE(HIGH) cellular model exhibited a loss of acetylated tubulin consistent with an outgrowth of secretory epithelial cells in culture. MOE(HIGH) cells proliferated significantly faster than MOE(LOW), and the MOE(HIGH) cells produced more 2D foci and 3D soft agar colonies as compared to MOE(LOW) MOE(HIGH) were xenografted into athymic female nude mice both in the subcutaneous and the intraperitoneal compartments. Only the subcutaneous grafts formed tumors that were negative for cytokeratin, but positive for oviductal markers, such as oviductal glycoprotein 1 and Pax8. These tumors were considered to be poorly differentiated carcinoma. The differential molecular profiles between MOE(HIGH) and MOE(LOW) were determined using RNA-Seq and confirmed by protein expression to uncover pathways important in transformation, like the p53 pathway, the FOXM1 pathway, WNT signaling, and splicing. MOE(HIGH) had enhanced protein expression of c-myc, Cyclin E, p53, and FOXM1 with reduced expression of p21. MOE(HIGH) were also less sensitive to cisplatin and DMBA, which induce lesions typically repaired by base-excision repair. A model of spontaneous tumorogenesis was generated starting with normal oviductal cells. Their transition to cancer involved alterations in pathways associated with high-grade serous cancer in humans.
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Affiliation(s)
- Michael P Endsley
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
| | - Georgette Moyle-Heyrman
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
| | - Subbulakshmi Karthikeyan
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
| | - Daniel D Lantvit
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
| | - David A Davis
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
| | - Jian-Jun Wei
- Department of Pathology, Northwestern University , Chicago, IL , USA
| | - Joanna E Burdette
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago , Chicago, IL , USA
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Chabot B. My road to alternative splicing control: from simple paths to loops and interconnections. Biochem Cell Biol 2015; 93:171-9. [PMID: 25759250 DOI: 10.1139/bcb-2014-0161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
With the functional importance of alternative splicing being validated in nearly every mammalian biological system and implicated in many human diseases, it is now crucial to identify the molecular programs that control the production of splice variants. In this article, I will survey how our knowledge of the basic principles of alternative splicing control evolved over the last 25 years. I will also describe how investigation of the splicing control of an apoptotic regulator led us to identify novel effectors and revealed the existence of converging pathways linking splicing decisions to DNA damage. Finally, I will review how our efforts at developing tools designed to monitor and redirect splicing helped assess the impact of misregulated splicing in cancer.
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Affiliation(s)
- Benoit Chabot
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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41
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Silipo M, Gautrey H, Tyson-Capper A. Deregulation of splicing factors and breast cancer development. J Mol Cell Biol 2015; 7:388-401. [PMID: 25948865 DOI: 10.1093/jmcb/mjv027] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/24/2015] [Indexed: 11/13/2022] Open
Abstract
It is well known that many genes implicated in the development and progression of breast cancer undergo aberrant alternative splicing events to produce proteins with pro-cancer properties. These changes in alternative splicing can arise from mutations or single-nucleotide polymorphisms (SNPs) within the DNA sequences of cancer-related genes, which can strongly affect the activity of splicing factors and influence the splice site choice. However, it is important to note that absence of mutations is not sufficient to prevent misleading choices in splice site selection. There is now increasing evidence to demonstrate that the expression profile of ten splicing factors (including SRs and hnRNPs) and eight RNA-binding proteins changes in breast cancer cells compared with normal cells. These modifications strongly influence the alternative splicing pattern of many cancer-related genes despite the absence of any detrimental mutations within their DNA sequences. Thus, a comprehensive assessment of the splicing factor status in breast cancer is important to provide insights into the mechanisms that lead to breast cancer development and metastasis. Whilst most studies focus on mutations that affect alternative splicing in cancer-related genes, this review focuses on splicing factors and RNA-binding proteins that are themselves deregulated in breast cancer and implicated in cancer-related alternative splicing events.
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Affiliation(s)
- Marco Silipo
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Hannah Gautrey
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Alison Tyson-Capper
- Institute of Cellular Medicine, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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McFarlane M, MacDonald AI, Stevenson A, Graham SV. Human Papillomavirus 16 Oncoprotein Expression Is Controlled by the Cellular Splicing Factor SRSF2 (SC35). J Virol 2015; 89:5276-87. [PMID: 25717103 PMCID: PMC4442513 DOI: 10.1128/jvi.03434-14] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 02/10/2015] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED High-risk human papillomaviruses (HR-HPV) cause anogenital cancers, including cervical cancer, and head and neck cancers. Human papillomavirus 16 (HPV16) is the most prevalent HR-HPV. HPV oncogenesis is driven by two viral oncoproteins, E6 and E7, which are expressed through alternative splicing of a polycistronic RNA to yield four major splice isoforms (E6 full length, E6*I, E6*II, E6*X). The production of multiple mRNA isoforms from a single gene is controlled by serine/arginine-rich splicing factors (SRSFs), and HPV16 infection induces overexpression of a subset of these, SRSFs 1, 2, and 3. In this study, we examined whether these proteins could control HPV16 oncoprotein expression. Small interfering RNA (siRNA) depletion experiments revealed that SRSF1 did not affect oncoprotein RNA levels. While SRSF3 knockdown caused some reduction in E6E7 expression, depletion of SRSF2 resulted in a significant loss of E6E7 RNAs, resulting in reduced levels of the E6-regulated p53 proteins and E7 oncoprotein itself. SRSF2 contributed to the tumor phenotype of HPV16-positive cervical cancer cells, as its depletion resulted in decreased cell proliferation, reduced colony formation, and increased apoptosis. SRSF2 did not affect transcription from the P97 promoter that controls viral oncoprotein expression. Rather, RNA decay experiments showed that SRSF2 is required to maintain stability of E6E7 mRNAs. These data show that SRSF2 is a key regulator of HPV16 oncoprotein expression and cervical tumor maintenance. IMPORTANCE Expression of the HPV16 oncoproteins E7 and E6 drives HPV-associated tumor formation. Although increased transcription may yield increased levels of E6E7 mRNAs, it is known that the RNAs can have increased stability upon integration into the host genome. SR splicing factors (SRSFs) control splicing but can also control other events in the RNA life cycle, including RNA stability. Previously, we demonstrated increased levels of SRSFs 1, 2, and 3 during cervical tumor progression. Now we show that SRSF2 is required for expression of E6E7 mRNAs in cervical tumor but not nontumor cells and may act by inhibiting their decay. SRSF2 depletion in W12 tumor cells resulted in increased apoptosis, decreased proliferation, and decreased colony formation, suggesting that SRSF2 has oncogenic functions in cervical tumor progression. SRSF function can be targeted by known drugs that inhibit SRSF phosphorylation, suggesting a possible new avenue in abrogating HPV oncoprotein activity.
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Affiliation(s)
- Melanie McFarlane
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Alasdair I MacDonald
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Andrew Stevenson
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Sheila V Graham
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
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Shilo A, Siegfried Z, Karni R. The role of splicing factors in deregulation of alternative splicing during oncogenesis and tumor progression. Mol Cell Oncol 2015; 2:e970955. [PMID: 27308389 PMCID: PMC4905244 DOI: 10.4161/23723548.2014.970955] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/13/2014] [Accepted: 09/15/2014] [Indexed: 04/18/2023]
Abstract
In past decades, cancer research has focused on genetic alterations that are detected in malignant tissues and contribute to the initiation and progression of cancer. These changes include mutations, copy number variations, and translocations. However, it is becoming increasingly clear that epigenetic changes, including alternative splicing, play a major role in cancer development and progression. There are relatively few studies on the contribution of alternative splicing and the splicing factors that regulate this process to cancer development and progression. Recently, multiple studies have revealed altered splicing patterns in cancers and several splicing factors were found to contribute to tumor development. Studies using high-throughput genomic analysis have identified mutations in components of the core splicing machinery and in splicing factors in several cancers. In this review, we will highlight new findings on the role of alternative splicing and its regulators in cancer initiation and progression, in addition to novel approaches to correct oncogenic splicing.
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Affiliation(s)
- Asaf Shilo
- Department of Biochemistry and Molecular Biology; Institute for Medical Research Israel-Canada; Hebrew University-Hadassah Medical School; Ein Karem, Jerusalem, Israel
| | - Zahava Siegfried
- Department of Biochemistry and Molecular Biology; Institute for Medical Research Israel-Canada; Hebrew University-Hadassah Medical School; Ein Karem, Jerusalem, Israel
| | - Rotem Karni
- Department of Biochemistry and Molecular Biology; Institute for Medical Research Israel-Canada; Hebrew University-Hadassah Medical School; Ein Karem, Jerusalem, Israel
- Correspondence to: Rotem Karni;
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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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He X, Arslan AD, Ho TT, Yuan C, Stampfer MR, Beck WT. Involvement of polypyrimidine tract-binding protein (PTBP1) in maintaining breast cancer cell growth and malignant properties. Oncogenesis 2014; 3:e84. [PMID: 24418892 PMCID: PMC3940912 DOI: 10.1038/oncsis.2013.47] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2013] [Revised: 11/13/2013] [Accepted: 11/14/2013] [Indexed: 12/12/2022] Open
Abstract
We have investigated some roles of splicing factor polypyrimidine tract-binding protein (PTBP1) in human breast cancer. We found that PTBP1 was upregulated in progressively transformed human mammary epithelial cells (HMECs), as well as in breast tumor cell lines compared with HMECs with finite growth potential and found that the level of PTBP1 correlated with the transformation state of HMECs. Knockdown of PTBP1 expression substantially inhibited tumor cell growth, colony formation in soft agar and in vitro invasiveness of breast cancer cell lines, a result similar to what we have reported in ovarian cancer. However, ectopic expression of PTBP1 (as a PTBP1-EGFP fusion protein) did not enhance the proliferation of immortalized HMEC. Rather, PTBP1 expression promoted anchorage-independent growth of an immortalized HMEC as assessed by increased colony formation in soft agar. In addition, we found that knockdown of PTBP1 expression led to upregulation of the expression of the M1 isoform of pyruvate kinase (PKM1) and increase of the ratio of PKM1 vs PKM2. PKM1 has been reported to promote oxidative phosphorylation and reduce tumorigenesis. Correspondingly, we observed increased oxygen consumption in PTBP1-knockdown breast cancer cells. Together, these results suggest that PTBP1 is associated with breast tumorigenesis and appears to be required for tumor cell growth and maintenance of transformed properties. PTBP1 exerts these effects, in part, by regulating the splicing of pyruvate kinase, and consequently alters glucose metabolism and contributes to the Warburg effect.
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Affiliation(s)
- X He
- 1] Department of Biopharmaceutical Sciences, College of Pharmacy-Rockford, University of Illinois at Chicago, Rockford, IL, USA [2] Cancer Center, University of Illinois, Chicago, IL, USA
| | - A D Arslan
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - T-T Ho
- Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
| | - C Yuan
- Department of Biopharmaceutical Sciences, College of Pharmacy-Rockford, University of Illinois at Chicago, Rockford, IL, USA
| | - M R Stampfer
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - W T Beck
- 1] Cancer Center, University of Illinois, Chicago, IL, USA [2] Department of Biopharmaceutical Sciences, College of Pharmacy, University of Illinois at Chicago, Chicago, IL, USA
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Kim J, Park RY, Chen JK, Kim J, Jeong S, Ohn T. Splicing factor SRSF3 represses the translation of programmed cell death 4 mRNA by associating with the 5'-UTR region. Cell Death Differ 2013; 21:481-90. [PMID: 24292556 DOI: 10.1038/cdd.2013.171] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 10/18/2013] [Accepted: 10/18/2013] [Indexed: 12/21/2022] Open
Abstract
Serine/arginine-rich splicing factor 3 (SRSF3), a member of the serine/arginine (SR)-rich family of proteins, regulates both alternative splicing of pre-mRNA and export of mature mRNA from the nucleus. Although its role in nuclear mRNA processing is well understood, the mechanism by which it alters the fate of cytoplasmic mRNA molecules remains elusive. Here, we provide evidence that SRSF3 not only regulates the alternative splicing pattern of programmed cell death 4 (PDCD4) mRNA, but also modulates its translational efficiency in the cytoplasm by lowering translation levels. We observed a marked increase in PDCD4 mRNA in translating polysome fractions upon silencing of SRSF3, and, conversely, ectopic overexpression of SRSF3 shifted PDCD4 mRNA into non-translating ribosomal fractions. In live cells, SRSF3 colocalized with PDCD4 mRNA in P-bodies (PBs), where translationally silenced mRNAs are deposited, and this localization was abrogated upon SRSF3 silencing. Furthermore, using two different reporter systems, we showed that SRSF3 interacts directly with PDCD4 mRNA and mediates translational repression by binding to the 5'-untranslated region (5'-UTR). In summary, our data suggest that the oncogenic potential of SRSF3 might be realized, in part, through the translational repression of PDCD4 mRNA.
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Affiliation(s)
- J Kim
- National Research Lab for RNA Cell Biology, Department of Molecular Biology, Dankook University, Yongin, Republic of Korea
| | - R Y Park
- Department of Cellular & Molecular Medicine, College of Medicine, Chosun University, Chosun, Republic of Korea
| | - J-K Chen
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, USA
| | - J Kim
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, USA
| | - S Jeong
- National Research Lab for RNA Cell Biology, Department of Molecular Biology, Dankook University, Yongin, Republic of Korea
| | - T Ohn
- Department of Cellular & Molecular Medicine, College of Medicine, Chosun University, Chosun, Republic of Korea
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Nuclear multidrug-resistance related protein 1 contributes to multidrug-resistance of mucoepidermoid carcinoma mainly via regulating multidrug-resistance protein 1: a human mucoepidermoid carcinoma cells model and Spearman's rank correlation analysis. PLoS One 2013; 8:e69611. [PMID: 24013781 PMCID: PMC3754958 DOI: 10.1371/journal.pone.0069611] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/11/2013] [Indexed: 12/28/2022] Open
Abstract
Background Multidrug resistance-related protein 1 (MRP1/ABCC1) and multidrug resistance protein 1 (MDR1/P-glycoprotein/ABCB1) are both membrane-bound drug transporters. In contrast to MDR1, MRP1 also transports glutathione (GSH) and drugs conjugated to GSH. Due to its extraordinary transport properties, MRP1/ABCC1 contributes to several physiological functions and pathophysiological incidents. We previously found that nuclear translocation of MRP1 contributes to multidrug-resistance (MDR) of mucoepidermoid carcinoma (MEC). The present study investigated how MRP1 contributes to MDR in the nuclei of MEC cells. Methods Western blot and RT-PCR was carried out to investigate the change of multidrug-resistance protein 1 (MDR1) in MC3/5FU cells after MRP1 was downregulated through RNA interference (RNAi). Immunohistochemistry (IHC) staining of 127 cases of MEC tissues was scored with the expression index (EI). The EI of MDR1 and MRP1 (or nuclear MRP1) was analyzed with Spearman's rank correlation analysis. Using multiple tumor tissue assays, the location of MRP1 in other tissues was checked by HIC. Luciferase reporter assays of MDR1 promoter was carried out to check the connection between MRP1 and MDR1 promoter. Results MRP1 downregulation led to a decreased MDR1 expression in MC3/5FU cells which was caused by decreased activity of MDR1 promoter. IHC study of 127 cases of MEC tissues demonstrated a strong positive correlation between nuclear MRP1 expression and MDR1 expression. Furthermore, IHC study of multiple tumor tissue array sections showed that although nuclear MRP1 widely existed in MEC tissues, it was not found in normal tissues or other tumor tissues. Conclusions Our findings indicate that nuclear MRP1 contributes to MDR mainly through regulating MDR1 expression in MEC. And the unique location of MRP1 made it an available target in identifying MEC from other tumors.
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Han S, Kim K, Thakkar N, Kim D, Lee W. Role of hypoxia inducible factor-1α in the regulation of the cancer-specific variant of organic anion transporting polypeptide 1B3 (OATP1B3), in colon and pancreatic cancer. Biochem Pharmacol 2013; 86:816-23. [PMID: 23924606 DOI: 10.1016/j.bcp.2013.07.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 07/21/2013] [Accepted: 07/23/2013] [Indexed: 01/29/2023]
Abstract
Organic anion transporting polypeptide 1B3 (OATP1B3) was initially considered to be a liver-specific transporter, mediating the uptake of a variety of endogenous and xenobiotic substances. Over the past decade, several investigations reported that OATP1B3 is also expressed across multiple types of cancers. Only recently, our laboratory and others demonstrated the identity of cancer-specific OATP1B3 variants (csOATP1B3) arising from the use of an alternative transcription initiation site, different from the wildtype (WT) OATP1B3 expressed in the normal liver. However, the mechanisms regulating the expression of csOATP1B3 remained unknown. In our current study, we investigated the role of hypoxia and the involvement of hypoxia inducible factor-1α (HIF-1α) in regulating the transcription of csOATP1B3. Our RT-PCR and immunoblotting results indicated that csOATP1B3, but not WT OATP1B3, can be induced in response to ambient or chemical hypoxia (upon exposure to 1% O₂ or cobalt chloride). Reporter assays with deletion and mutated constructs of the csOATP1B3 promoter revealed a functional hypoxia response element (HRE) located in the proximal upstream region. Constructs harboring the HRE displayed the upregulated reporter gene expression in response to hypoxia, but not when mutated. Electrophoretic mobility shift assays using a biotin-labeled csOATP1B3 promoter HRE probe indicated the binding of HIF-1α, which was blocked by an excess of unlabeled csOATP1B3 probe. Furthermore, siRNA-based knockdown of HIF-1α caused a substantial decrease in the expression level of csOATP1B3. Taken together, these findings demonstrate that the transcription of csOATP1B3 is actively engaged during hypoxia, through a commonly utilized pathway involving HIF-1α.
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Affiliation(s)
- Songhee Han
- Department of Biological Sciences, Konkuk University, Seoul 143-701, Republic of Korea
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Membrane expression of MRP-1, but not MRP-1 splicing or Pgp expression, predicts survival in patients with ESFT. Br J Cancer 2013; 109:195-206. [PMID: 23799853 PMCID: PMC3708562 DOI: 10.1038/bjc.2013.168] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 03/19/2013] [Accepted: 03/21/2013] [Indexed: 12/22/2022] Open
Abstract
Background: Primary Ewing's sarcoma family of tumours (ESFTs) may respond to chemotherapy, although many patients experience subsequent disease recurrence and relapse. The survival of ESFT cells following chemotherapy has been attributed to the development of resistant disease, possibly through the expression of ABC transporter proteins. Methods: MRP-1 and Pgp mRNA and protein expression in primary ESFTs was determined by quantitative reverse-transcriptase PCR (RT-qPCR) and immunohistochemistry, respectively, and alternative splicing of MRP-1 by RT-PCR. Results: We observed MRP-1 protein expression in 92% (43 out of 47) of primary ESFTs, and cell membrane MRP-1 was highly predictive of both overall survival (P<0.0001) and event-free survival (P<0.0001). Alternative splicing of MRP-1 was detected in primary ESFTs, although the pattern of splicing variants was not predictive of patient outcome, with the exception of loss of exon 9 in six patients, which predicted relapse (P=0.041). Pgp protein was detected in 6% (38 out of 44) of primary ESFTs and was not associated with patient survival. Conclusion: For the first time we have established that cell membrane expression of MRP-1 or loss of exon 9 is predictive of outcome but not the number of splicing events or expression of Pgp, and both may be valuable factors for the stratification of patients for more intensive therapy.
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Bhat-Nakshatri P, Song EK, Collins NR, Uversky VN, Dunker AK, O'Malley BW, Geistlinger TR, Carroll JS, Brown M, Nakshatri H. Interplay between estrogen receptor and AKT in estradiol-induced alternative splicing. BMC Med Genomics 2013; 6:21. [PMID: 23758675 PMCID: PMC3687557 DOI: 10.1186/1755-8794-6-21] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 06/03/2013] [Indexed: 02/07/2023] Open
Abstract
Background Alternative splicing is critical for generating complex proteomes in response to extracellular signals. Nuclear receptors including estrogen receptor alpha (ERα) and their ligands promote alternative splicing. The endogenous targets of ERα:estradiol (E2)-mediated alternative splicing and the influence of extracellular kinases that phosphorylate ERα on E2-induced splicing are unknown. Methods MCF-7 and its anti-estrogen derivatives were used for the majority of the assays. CD44 mini gene was used to measure the effect of E2 and AKT on alternative splicing. ExonHit array analysis was performed to identify E2 and AKT-regulated endogenous alternatively spliced apoptosis-related genes. Quantitative reverse transcription polymerase chain reaction was performed to verify alternative splicing. ERα binding to alternatively spliced genes was verified by chromatin immunoprecipitation assay. Bromodeoxyuridine incorporation-ELISA and Annexin V labeling assays were done to measure cell proliferation and apoptosis, respectively. Results We identified the targets of E2-induced alternative splicing and deconstructed some of the mechanisms surrounding E2-induced splicing by combining splice array with ERα cistrome and gene expression array. E2-induced alternatively spliced genes fall into at least two subgroups: coupled to E2-regulated transcription and ERα binding to the gene without an effect on rate of transcription. Further, AKT, which phosphorylates both ERα and splicing factors, influenced ERα:E2 dependent splicing in a gene-specific manner. Genes that are alternatively spliced include FAS/CD95, FGFR2, and AXIN-1. E2 increased the expression of FGFR2 C1 isoform but reduced C3 isoform at mRNA level. E2-induced alternative splicing of FAS and FGFR2 in MCF-7 cells correlated with resistance to FAS activation-induced apoptosis and response to keratinocyte growth factor (KGF), respectively. Resistance of MCF-7 breast cancer cells to the anti-estrogen tamoxifen was associated with ERα-dependent overexpression of FGFR2, whereas resistance to fulvestrant was associated with ERα-dependent isoform switching, which correlated with altered response to KGF. Conclusion E2 may partly alter cellular proteome through alternative splicing uncoupled to its effects on transcription initiation and aberration in E2-induced alternative splicing events may influence response to anti-estrogens.
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Affiliation(s)
- Poornima Bhat-Nakshatri
- Department of Surgery, Indiana University School of Medicine, 980 West Walnut Street, Indianapolis, IN 46202, USA
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