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Shi H, Li H, Yuan R, Guan W, Zhang X, Zhang S, Zhang W, Tong F, Li L, Song Z, Wang C, Yang S, Wang H. PCBP1 depletion promotes tumorigenesis through attenuation of p27 Kip1 mRNA stability and translation. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2018; 37:187. [PMID: 30086790 PMCID: PMC6081911 DOI: 10.1186/s13046-018-0840-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/10/2018] [Indexed: 11/10/2022]
Abstract
Background Poly C Binding Protein 1 (PCBP1) is an RNA-binding protein that binds and regulates translational activity of subsets of cellular mRNAs. Depletion of PCBP1 is implicated in various carcinomas, but the underlying mechanism in tumorigenesis remains elusive. Methods We performed a transcriptome-wide screen to identify novel bounding mRNA of PCBP1. The bind regions between PCBP1 with target mRNA were investigated by using point mutation and luciferase assay. Cell proliferation, cell cycle, tumorigenesis and cell apoptosis were also evaluated in ovary and colon cancer cell lines. The mechanism that PCBP1 affects p27 was analyzed by mRNA stability and ribosome profiling assays. We analyzed PCBP1 and p27 expression in ovary, colon and renal tumor samples and adjacent non-tumor tissues using RT-PCR, Western Blotting and immunohistochemistry. The prognostic significance of PCBP1 and p27 also analyzed using online databases. Results We identified cell cycle inhibitor p27Kip1 (p27) as a novel PCBP1-bound transcript. We then demonstrated that binding of PCBP1 to p27 3’UTR via its KH1 domain mainly stabilizes p27 mRNA, while enhances its translation to fuel p27 expression, prior to p27 protein degradation. The upregulated p27 consequently inhibits cell proliferation, cell cycle progression and tumorigenesis, whereas promotes cell apoptosis under paclitaxel treatment. Conversely, knockdown of PCBP1 in turn compromises p27 mRNA stability, leading to lower p27 level and tumorigenesis in vivo. Moreover, forced depletion of p27 counteracts the tumor suppressive ability of PCBP1 in the same PCBP1 over-expressing cells. Physiologically, we showed that decreases of both p27 mRNA and its protein expressions are well correlated to PCBP1 depletion in ovary, colon and renal tumor samples, independent of the p27 ubiquitin ligase Skp2 level. Correlation of PCBP1 with p27 is also found in the tamoxifen, doxorubincin and lapatinib resistant breast cancer cells of GEO database. Conclusion Our results thereby indicate that loss of PCBP1 expression firstly attenuates p27 expression at post-transcriptional level, and subsequently promotes carcinogenesis. PCBP1 could be used as a diagnostic marker to cancer patients. Electronic supplementary material The online version of this article (10.1186/s13046-018-0840-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongshun Shi
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Hui Li
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China.,Center for Stem Cell Biology and Tissue Engineering, Key laboratory of ministry of education, Sun Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Ronghua Yuan
- Department of General Surgery, The Second Affiliated Hospital of Nantong University, Nantong University, Nantong, 226001, China
| | - Wen Guan
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Xiaomei Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Shaoyang Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Wenliang Zhang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Fang Tong
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Li Li
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.,Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Zhihong Song
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China
| | - Changwei Wang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, 510530, China
| | - Shulan Yang
- Centre for Translational Medicine, the First Affiliated Hospital, SUN Yat-sen University, 58 Second Zhongshan Road, Guangzhou, 510080, China.
| | - Haihe Wang
- Department of Biochemistry, Zhongshan School of Medicine, SUN Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China. .,Center for Stem Cell Biology and Tissue Engineering, Key laboratory of ministry of education, Sun Yat-sen University, 74 Second Zhongshan Road, Guangzhou, 510080, China.
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Hunkele A, Sultan H, Ikalina FA, Liu AH, Nahar-Gohad P, Ko JL. Identification of gamma-synuclein as a new PCBP1-interacting protein. Neurol Res 2016; 38:1064-1078. [PMID: 26344801 DOI: 10.1179/1743132815y.0000000091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
OBJECTIVES PolyC binding protein 1 (PCBP1) is a transcriptional regulator of human mu-opioid receptor (hMOR) gene in the CNS and is also related to cancer/diseases. It possesses multi-roles that can be mediated by protein-protein interactions. To understand the mechanism controlling PCBP1 functions, PCBP1-interacting protein was investigated. METHODS Using PCBP1 as the bait, a human brain cDNA library was screened via two-hybrid system. DNA sequence of candidate protein was confirmed using NCBI/SNP databases. Candidate protein in various cell lines was examined by RT-PCR. Glutathione-S-transferase (GST) pull-down and co-immunoprecipitation were used to validate the physical interaction. Its effects on hMOR gene regulation were examined. RESULTS One clone was identified as gamma-synuclein110E, an SNP of gamma-synuclein110V. The interaction between PCBP1 and gamma-synuclein110E was confirmed by further validation and GST pull-down assay. Confocal analysis showed gamma-synuclein110E mainly expressing in the cytosol of human neuronal NMB cells. This interaction was confirmed by co-immunoprecipitation with NMB lysates, containing both proteins endogenously. Ectopic expression of gamma-synuclein110E or 110V did not alter hMOR mRNA level or promoter activity, suggesting no involvement of gamma-synuclein in modulating hMOR expression. Co-immunoprecipitation using gamma-synuclein110E or 110V overexpressed NMB cells with anti-PCBP1 antibody revealed a stronger intensity of co-immunoprecipitated gamma-synuclein band using gamma-synuclein110E-overexpressed cells as compared to that using gamma-synuclein110V-overexpressed cells. Synuclein110E was also identified in H292 (lung), HT29 (colon) and T47D (breast) cells, and this physical interaction was confirmed. CONCLUSION We report a newly identified PCBP1-interacting protein, gamma-synuclein110E, and provide some insight into its complex role as well as discuss potential roles of this interaction.
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Affiliation(s)
- Amanda Hunkele
- a Department of Biological Sciences ; Seton Hall University , USA
| | - Hamidah Sultan
- a Department of Biological Sciences ; Seton Hall University , USA
| | - Faith A Ikalina
- a Department of Biological Sciences ; Seton Hall University , USA
| | - Alexander H Liu
- a Department of Biological Sciences ; Seton Hall University , USA
| | | | - Jane L Ko
- a Department of Biological Sciences ; Seton Hall University , USA
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Napthine S, Treffers EE, Bell S, Goodfellow I, Fang Y, Firth AE, Snijder EJ, Brierley I. A novel role for poly(C) binding proteins in programmed ribosomal frameshifting. Nucleic Acids Res 2016; 44:5491-503. [PMID: 27257056 PMCID: PMC4937337 DOI: 10.1093/nar/gkw480] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/18/2016] [Indexed: 01/16/2023] Open
Abstract
Translational control through programmed ribosomal frameshifting (PRF) is exploited widely by viruses and increasingly documented in cellular genes. Frameshifting is induced by mRNA secondary structures that compromise ribosome fidelity during decoding of a heptanucleotide 'slippery' sequence. The nsp2 PRF signal of porcine reproductive and respiratory syndrome virus is distinctive in directing both -2 and -1 PRF and in its requirement for a trans-acting protein factor, the viral replicase subunit nsp1β. Here we show that the the trans-activation of frameshifting is carried out by a protein complex composed of nsp1β and a cellular poly(C) binding protein (PCBP). From the results of in vitro translation and electrophoretic mobility shift assays, we demonstrate that a PCBP/nsp1β complex binds to a C-rich sequence downstream of the slippery sequence and here mimics the activity of a structured mRNA stimulator of PRF. This is the first description of a role for a trans-acting cellular protein in PRF. The discovery broadens the repertoire of activities associated with poly(C) binding proteins and prototypes a new class of virus-host interactions.
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Affiliation(s)
- Sawsan Napthine
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Emmely E Treffers
- Department of Medical Microbiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Susanne Bell
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Ian Goodfellow
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Ying Fang
- College of Veterinary Medicine, Kansas State University, Manhattan, KS 66506-5705, USA
| | - Andrew E Firth
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
| | - Eric J Snijder
- Department of Medical Microbiology, Leiden University Medical Center, P.O. Box 9600, 2300 RC Leiden, The Netherlands
| | - Ian Brierley
- Department of Pathology, University of Cambridge, Cambridge, CB2 1QP, UK
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Transactivation of programmed ribosomal frameshifting by a viral protein. Proc Natl Acad Sci U S A 2014; 111:E2172-81. [PMID: 24825891 DOI: 10.1073/pnas.1321930111] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Programmed -1 ribosomal frameshifting (-1 PRF) is a widely used translational mechanism facilitating the expression of two polypeptides from a single mRNA. Commonly, the ribosome interacts with an mRNA secondary structure that promotes -1 frameshifting on a homopolymeric slippery sequence. Recently, we described an unusual -2 frameshifting (-2 PRF) signal directing efficient expression of a transframe protein [nonstructural protein 2TF (nsp2TF)] of porcine reproductive and respiratory syndrome virus (PRRSV) from an alternative reading frame overlapping the viral replicase gene. Unusually, this arterivirus PRF signal lacks an obvious stimulatory RNA secondary structure, but as confirmed here, can also direct the occurrence of -1 PRF, yielding a third, truncated nsp2 variant named "nsp2N." Remarkably, we now show that both -2 and -1 PRF are transactivated by a protein factor, specifically a PRRSV replicase subunit (nsp1β). Embedded in nsp1β's papain-like autoproteinase domain, we identified a highly conserved, putative RNA-binding motif that is critical for PRF transactivation. The minimal RNA sequence required for PRF was mapped within a 34-nt region that includes the slippery sequence and a downstream conserved CCCANCUCC motif. Interaction of nsp1β with the PRF signal was demonstrated in pull-down assays. These studies demonstrate for the first time, to our knowledge, that a protein can function as a transactivator of ribosomal frameshifting. The newly identified frameshifting determinants provide potential antiviral targets for arterivirus disease control and prevention. Moreover, protein-induced transactivation of frameshifting may be a widely used mechanism, potentially including previously undiscovered viral strategies to regulate viral gene expression and/or modulate host cell translation upon infection.
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Dong ZF, Tang LJ, Deng GF, Zeng T, Liu SJ, Wan RP, Liu T, Zhao QH, Yi YH, Liao WP, Long YS. Transcription of the human sodium channel SCN1A gene is repressed by a scaffolding protein RACK1. Mol Neurobiol 2014; 50:438-48. [PMID: 24436055 DOI: 10.1007/s12035-014-8633-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/02/2014] [Indexed: 11/29/2022]
Abstract
Voltage-gated sodium channel α subunit type I (Nav1.1, encoded by SCN1A gene) plays a critical role in the initiation of action potential in the central nervous system. Downregulated expression of SCN1A is believed to be associated with epilepsy. Here, we found that the SCN1A promoter (P1c), located at the 5' untranslated exon 1c, drove the reporter gene expression in human NT2 cells, and a region between nt +53 and +62 downstream of the P1c promoter repressed the promoter activity. Further analyses showed that a scaffolding protein RACK1 (receptor for activated C kinase 1) was involved in binding to this silencer. Knockdown of RACK1 expression in NT2 cells deprived the repressive role of the silencer on the P1c promoter and increased SCN1A transcription, suggesting the potential involvement of RACK1 in negatively regulating SCN1A transcription via interaction with the silencer. Furthermore, we demonstrated that the binding of the protein complex including RACK1 to the SCN1A promoter motif was decreased in neuron-like differentiation of the NT2 cells induced by retinoic acid and resulted in the upregulation of SCN1A transcription. Taken together, this study reports a novel role of RACK1 in regulating SCN1A expression that participates in retinoic acid-induced neuronal differentiation of NT2 cells.
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Affiliation(s)
- Zhao-Fei Dong
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, 250 Changgang East Road, Guangzhou, 510260, China
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Amanzada A, Malik IA, Blaschke M, Khan S, Rahman H, Ramadori G, Moriconi F. Identification of CD68(+) neutrophil granulocytes in in vitro model of acute inflammation and inflammatory bowel disease. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2013; 6:561-570. [PMID: 23573303 PMCID: PMC3606846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 01/05/2013] [Accepted: 02/26/2013] [Indexed: 06/02/2023]
Abstract
CD-68 is widely regarded as a selective marker for human monocytes and macrophages and is commonly used in human pathology studies. The purpose of this study was to investigate the expression of CD-68 in human peripheral blood mononuclear cells (PBMCs), neutrophil granulocytes (NGs) and in inflamed intestinal tissue samples for comparison. PBMCs and NGs were isolated from heparinized human blood samples. Intestinal biopsies were obtained during routine endoscopic procedures from patients with inflammatory bowel disease (IBD), e.g. ulcerative colitis and Crohn's disease. Gene and protein expression was analyzed by real-time RT-PCR, Western blot and immunohistochemistry. Both PBMCs and NGs preparations contained cells that were positive for CD-68 and either neutrophil elastase (NE), or myeloperoxidase (MPO). CD-68(+)/NE(-)/MPO(-) cells were regarded as monocytes. CD-68 mRNA expression was detected in PBMCs and NGs preparations. With Western blot and by performing immunoprecipitation of cell lysate, we could clearly detect CD-68 in NGs, U-937, THP-1, Hep-G2, Jurkat cells and PBMCs. Identification of inflammatory cells in acutely inflamed colonic mucosa obtained from patients with IBD revealed a strong accumulation of CD-68(+)/MPO(+) cells compared to normal colonic mucosa. The uptake of the marker by phagocytosis was excluded by performing a double staining with CD-163/NE and CD-163/MPO in PBMCs, NGs cultures and in inflamed colonic mucosa. These results identify CD-68(+) NGs in peripheral blood and inflamed colonic mucosa. CD-68 is not only a marker for the macrophages-monocytes but also for NGs.
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Affiliation(s)
- Ahmad Amanzada
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
| | - Ihtzaz Ahmed Malik
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
| | - Martina Blaschke
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
| | - Sajjad Khan
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
| | - Hazir Rahman
- Department of Clinical Chemistry, University Medical Center, Georg-August-University GöttingenGermany
| | - Giuliano Ramadori
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
| | - Federico Moriconi
- Division of Gastroenterology and Endocrinology, Department of Internal Medicine, University Medical Center, Georg-August-University GöttingenGermany
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