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Wan Makhtar WR, Browne G, Karountzos A, Stevens C, Alghamdi Y, Bottrill AR, Mistry S, Smith E, Bushel M, Pringle JH, Sayan AE, Tulchinsky E. Short stretches of rare codons regulate translation of the transcription factor ZEB2 in cancer cells. Oncogene 2017; 36:6640-6648. [PMID: 28783176 PMCID: PMC5681250 DOI: 10.1038/onc.2017.273] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/16/2017] [Accepted: 07/03/2017] [Indexed: 01/14/2023]
Abstract
Two proteins comprising the ZEB family of zinc finger transcription factors, ZEB1 and ZEB2, execute EMT programs in embryonic development and cancer. By studying regulation of their expression, we describe a novel mechanism that limits ZEB2 protein synthesis. A protein motif located at the border of the SMAD-binding domain of ZEB2 protein induces ribosomal pausing and compromises protein synthesis. The function of this protein motif is dependent on stretches of rare codons, Leu(UUA)-Gly(GGU)-Val(GUA). Incorporation of these triplets in the homologous region of ZEB1 does not affect protein translation. Our data suggest that rare codons have a regulatory role only if they are present within appropriate protein structures. We speculate that pools of transfer RNA available for protein translation impact on the configuration of epithelial mesenchymal transition pathways in tumor cells.
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Affiliation(s)
- W R Wan Makhtar
- Department of Cancer Studies, University of Leicester, Leicester, UK
- MRC Toxicology Unit, Leicester, UK
| | - G Browne
- Department of Cancer Studies, University of Leicester, Leicester, UK
| | - A Karountzos
- Department of Cancer Studies, University of Leicester, Leicester, UK
| | - C Stevens
- Department of Cancer Studies, University of Leicester, Leicester, UK
| | - Y Alghamdi
- Department of Cancer Studies, University of Leicester, Leicester, UK
| | - A R Bottrill
- Protein and Nucleic Acid Chemistry Laboratory (PNACL), University of Leicester, Leicester, UK
| | - S Mistry
- Protein and Nucleic Acid Chemistry Laboratory (PNACL), University of Leicester, Leicester, UK
| | - E Smith
- MRC Toxicology Unit, Leicester, UK
| | - M Bushel
- MRC Toxicology Unit, Leicester, UK
| | - J H Pringle
- Department of Cancer Studies, University of Leicester, Leicester, UK
| | - A E Sayan
- Cancer Sciences Division, University of Southampton, Southampton, UK
| | - E Tulchinsky
- Department of Cancer Studies, University of Leicester, Leicester, UK
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3
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Sayan AE, Sayan BS, Gogvadze V, Dinsdale D, Nyman U, Hansen TM, Zhivotovsky B, Cohen GM, Knight RA, Melino G. P73 and caspase-cleaved p73 fragments localize to mitochondria and augment TRAIL-induced apoptosis. Oncogene 2008; 27:4363-72. [PMID: 18362891 DOI: 10.1038/onc.2008.64] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The p73 protein, a member of the p53 family, has both developmental and tumorigenic functions. Here we show that p73 is cleaved by caspase-3 and -8 both in vitro and in vivo during apoptosis elicited by DNA-damaging drugs and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor ligation. TAp73 and some of its cleavage products are localized to mitochondria. siRNA-mediated downregulation of p73 expression induced a small but significant change in the susceptibility of HCT116 cells to TRAIL-induced apoptosis. A transcription-deficient mutant of TAp73 enhanced TRAIL-induced apoptosis suggesting that p73 protein has transcription-independent functions during death receptor-mediated apoptosis. Additionally, recombinant p73 protein induced cytochrome c release from isolated mitochondria providing evidence that nonnuclear p73 may have additional functions in the progression of apoptosis.
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Affiliation(s)
- A E Sayan
- MRC Toxicology Unit, University of Leicester, Leicester, UK
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4
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Barcaroli D, Dinsdale D, Neale MH, Bongiorno-Borbone L, Ranalli M, Munarriz E, Sayan AE, McWilliam JM, Smith TM, Fava E, Knight RA, Melino G, De Laurenzi V. FLASH is an essential component of Cajal bodies. Proc Natl Acad Sci U S A 2006; 103:14802-7. [PMID: 17003126 PMCID: PMC1578500 DOI: 10.1073/pnas.0604225103] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cajal bodies are small nuclear organelles with a number of nuclear functions. Here we show that FLICE-associated huge protein (FLASH), originally described as a component of the apoptosis signaling pathway, is mainly localized in Cajal bodies and is essential for their structure. Reduction in FLASH expression by short hairpin RNA results in disruption of the normal architecture of the Cajal body and relocalization of its components. Because the function of FLASH in the apoptosis receptor signaling pathway has been strongly questioned, we have now identified a clear function for this protein.
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Affiliation(s)
- D. Barcaroli
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
- Fondazione S. Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Centro Europeo di Ricerca sul Cervello, Via del Fosso di Fiorano 64/65, 00143 Rome, Italy
| | - D. Dinsdale
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - M. H. Neale
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - L. Bongiorno-Borbone
- Department of Experimental Medicine, University of Rome “Tor Vergata,” Via Montpellier 1, 00133 Rome, Italy; and
- Fondazione S. Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Centro Europeo di Ricerca sul Cervello, Via del Fosso di Fiorano 64/65, 00143 Rome, Italy
| | - M. Ranalli
- Department of Experimental Medicine, University of Rome “Tor Vergata,” Via Montpellier 1, 00133 Rome, Italy; and
| | - E. Munarriz
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - A. E. Sayan
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - J. M. McWilliam
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - T. M. Smith
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - E. Fava
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - R. A. Knight
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
| | - G. Melino
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
- Department of Experimental Medicine, University of Rome “Tor Vergata,” Via Montpellier 1, 00133 Rome, Italy; and
- Fondazione S. Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Centro Europeo di Ricerca sul Cervello, Via del Fosso di Fiorano 64/65, 00143 Rome, Italy
| | - V. De Laurenzi
- *Medical Research Council, Toxicology Unit, Leicester University, Hodgkin Building, Lancaster Road, P.O. Box 138, Leicester LE1 9HN, United Kingdom
- Department of Experimental Medicine, University of Rome “Tor Vergata,” Via Montpellier 1, 00133 Rome, Italy; and
- Fondazione S. Lucia, Istituto di Ricovero e Cura a Carattere Scientifico, Centro Europeo di Ricerca sul Cervello, Via del Fosso di Fiorano 64/65, 00143 Rome, Italy
- To whom correspondence should be addressed. E-mail:
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Müller M, Schilling T, Sayan AE, Kairat A, Lorenz K, Schulze-Bergkamen H, Oren M, Koch A, Tannapfel A, Stremmel W, Melino G, Krammer PH. TAp73/Delta Np73 influences apoptotic response, chemosensitivity and prognosis in hepatocellular carcinoma. Cell Death Differ 2005; 12:1564-77. [PMID: 16195739 DOI: 10.1038/sj.cdd.4401774] [Citation(s) in RCA: 143] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We investigated the mechanisms by which TAp73 beta and dominant-negative p73 (Delta Np73) regulate apoptosis. TAp73 beta transactivated the CD95 gene via the p53-binding site in the first intron. In addition, TAp73 beta induced expression of proapoptotic Bcl-2 family members and led to apoptosis via the mitochondrial pathway. Endogenous TAp73 was upregulated in response to DNA damage by chemotherapeutic drugs. On the contrary, DeltaNp73 conferred resistance to chemotherapy. Inhibition of CD95 gene transactivation was one mechanism by which DeltaNp73 functionally inactivated the tumor suppressor action of p53 and TAp73 beta. Concomitantly, DeltaNp73 inhibited apoptosis emanating from mitochondria. Thus, DeltaNp73 expression in tumors selects against both the death receptor and the mitochondrial apoptosis activity of TAp73 beta. The importance of these data is evidenced by our finding that upregulation of DeltaNp73 in hepatocellular carcinoma patients correlates with reduced survival. Our data indicate that Delta Np73 is an important gene in hepatocarcinogenesis and a relevant prognostic factor.
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Affiliation(s)
- M Müller
- Department of Internal Medicine IV, Hepatology and Gastroenterology, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.
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Ugur H, Sayan AE, Ozdamar SO, Kanpolat Y, Ozturk M. Expression of TAP73 and DeltaNP73 in malignant gliomas. Oncol Rep 2004; 11:1337-41. [PMID: 15138575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
The p73 gene is able to encode transcriptionaly active TAp73, as well as a dominant-negatively acting DeltaNp73 transcript isoforms. We studied differential expression of these forms in normal brain as well as glial tumors, by semiquantitative RT-PCR. The expression of p73 was low or undetectable in normal brain tissues. Most of the tumors and non-tumor brain tissues also lacked significant expression of p73 in patients with low-grade astrocytomas. In contrast, most high-grade glial tumors displayed strong up-regulation of TAp73, whereas only a few displayed DeltaNp73 expression. These aberrations may reflect the inactivation of retinoblastoma pathway in these tumors which result in the activation of E2F transcription factors, since TAp73 is a known target of E2F1 gene. The study of TAp73 expression in brain tumors may serve as a means to evaluate the retinoblastoma pathway-dependent tumor progression.
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Affiliation(s)
- Hasan Ugur
- Department of Molecular Biology and Genetics, Bilkent University, 06800 Ankara, Turkey
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Abstract
Apoptosis or programmed cell death plays a pivotal role in embryonic development and maintenance of homeostasis. It is also involved in the etiology of pathophysiological conditions such as cancer, neurodegenerative, autoimmune, infectious, and heart diseases. Consequently, the study of apoptosis is now at center of both basic and clinical research applications. Therefore, sensitive and simple apoptosis detection techniques are required. Here we describe a monoclonal antibody-defined novel antigen, namely NAPO (negative in apoptosis), which is specifically lost during apoptosis. The anti-NAPO antibody recognizes two nuclear polypeptides of 60 and 70 kD. The antigen is maintained in quiescent and senescent cells, as well as in different phases of the cell cycle, including mitosis. Thus, immunodetection of NAPO antigen provides a specific, sensitive, and easy method for differential identification of apoptotic and nonapoptotic cells.
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Affiliation(s)
- B S Sayan
- Department of Molecular Biology, Bilkent University, 06533 Ankara, Turkey
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Sayan AE, Sayan BS, Findikli N, Ozturk M. Acquired expression of transcriptionally active p73 in hepatocellular carcinoma cells. Oncogene 2001; 20:5111-7. [PMID: 11526499 DOI: 10.1038/sj.onc.1204669] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2001] [Revised: 05/08/2001] [Accepted: 05/24/2001] [Indexed: 12/17/2022]
Abstract
p53 and p73 proteins activate similar target genes and induce apoptosis and cell cycle arrest. However, p53, but not p73 is considered a tumour-suppressor gene. Unlike p53, p73 deficiency in mice does not lead to a cancer-prone phenotype, and p73 gene is not mutated in human cancers, including hepatocellular carcinoma. Here we report that normal liver cells express only DeltaN-p73 transcript forms giving rise to the synthesis of N-terminally truncated, transcriptionally inactive and dominant negative p73 proteins. In contrast, most hepatocellular carcinoma cells express TA-p73 transcript forms encoding full-length and transcriptionally active p73 proteins, in addition to DeltaN-p73. We also show that together with the acquired expression of TA-p73, the 'retinoblastoma pathway' is inactivated, and E2F1-target genes including cyclin E and p14(ARF) are activated in hepatocellular carcinoma. However, there was no full correlation between 'retinoblastoma pathway' inactivation and TA-p73 expression. Most TA-p73-expressing hepatocellular carcinoma cells have also lost p53 function either by lack of expression or missense mutations. The p73 gene, encoding only DeltaN-p73 protein, may function as a tumour promoter rather than a tumour suppressor in liver tissue. This may be one reason why p73 is not a mutation target in hepatocellular carcinoma.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Western
- COS Cells
- Carcinoma, Hepatocellular/genetics
- Carcinoma, Hepatocellular/metabolism
- DNA, Complementary/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Genes, Dominant
- Genes, Tumor Suppressor
- Humans
- Liver/metabolism
- Liver Neoplasms/genetics
- Liver Neoplasms/metabolism
- Mice
- Mice, Inbred BALB C
- Models, Genetic
- Molecular Sequence Data
- Mutation
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Phenotype
- Protein Isoforms
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription, Genetic
- Tumor Cells, Cultured
- Tumor Protein p73
- Tumor Suppressor Proteins
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Affiliation(s)
- A E Sayan
- Department of Molecular Biology and Genetics, Bilkent University, 06533, Ankara, Turkey
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