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Bhattacharjee S, Rehman I, Basu S, Nandy S, Richardson JM, Das BB. Interplay between symmetric arginine dimethylation and ubiquitylation regulates TDP1 proteostasis for the repair of topoisomerase I-DNA adducts. Cell Rep 2022; 39:110940. [PMID: 35705029 DOI: 10.1016/j.celrep.2022.110940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 04/05/2022] [Accepted: 05/20/2022] [Indexed: 11/03/2022] Open
Abstract
Tyrosyl-DNA phosphodiesterase (TDP1) hydrolyzes the phosphodiester bond between a DNA 3' end and a tyrosyl moiety and is implicated in the repair of trapped topoisomerase I (Top1)-DNA covalent complexes (Top1cc). Protein arginine methyltransferase 5 (PRMT5) catalyzes arginine methylation of TDP1 at the residues R361 and R586. Here, we establish mechanistic crosstalk between TDP1 arginine methylation and ubiquitylation, which is critical for TDP1 homeostasis and cellular responses to Top1 poisons. We show that R586 methylation promotes TDP1 ubiquitylation, which facilitates ubiquitin/proteasome-dependent TDP1 turnover by impeding the binding of UCHL3 (deubiquitylase enzyme) with TDP1. TDP1-R586 also promotes TDP1-XRCC1 binding and XRCC1 foci formation at Top1cc-damage sites. Intriguingly, R361 methylation enhances the 3'-phosphodiesterase activity of TDP1 in real-time fluorescence-based cleavage assays, and this was rationalized using structural modeling. Together, our findings establish arginine methylation as a co-regulator of TDP1 proteostasis and activity, which modulates the repair of trapped Top1cc.
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Affiliation(s)
- Sangheeta Bhattacharjee
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Ishita Rehman
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Saini Basu
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Souvik Nandy
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Julia M Richardson
- Institute of Quantitative Biology, Biochemistry, and Biotechnology, School of Biological Sciences, University of Edinburgh, The King's Buildings, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Benu Brata Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
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Bhattacharjee S, Rehman I, Nandy S, Das BB. Post-translational regulation of Tyrosyl-DNA phosphodiesterase (TDP1 and TDP2) for the repair of the trapped topoisomerase-DNA covalent complex. DNA Repair (Amst) 2022; 111:103277. [DOI: 10.1016/j.dnarep.2022.103277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/24/2021] [Accepted: 01/20/2022] [Indexed: 12/23/2022]
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Ghosh A, Bhattacharjee S, Chowdhuri SP, Mallick A, Rehman I, Basu S, Das BB. SCAN1-TDP1 trapping on mitochondrial DNA promotes mitochondrial dysfunction and mitophagy. Sci Adv 2019; 5:eaax9778. [PMID: 31723605 PMCID: PMC6834389 DOI: 10.1126/sciadv.aax9778] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 09/17/2019] [Indexed: 05/03/2023]
Abstract
A homozygous mutation of human tyrosyl-DNA phosphodiesterase 1 (TDP1) causes the neurodegenerative syndrome, spinocerebellar ataxia with axonal neuropathy (SCAN1). TDP1 hydrolyzes the phosphodiester bond between DNA 3'-end and a tyrosyl moiety within trapped topoisomerase I (Top1)-DNA covalent complexes (Top1cc). TDP1 is critical for mitochondrial DNA (mtDNA) repair; however, the role of mitochondria remains largely unknown for the etiology of SCAN1. We demonstrate that mitochondria in cells expressing SCAN1-TDP1 (TDP1H493R) are selectively trapped on mtDNA in the regulatory non-coding region and promoter sequences. Trapped TDP1H493R-mtDNA complexes were markedly increased in the presence of the Top1 poison (mito-SN38) when targeted selectively into mitochondria in nanoparticles. TDP1H493R-trapping accumulates mtDNA damage and triggers Drp1-mediated mitochondrial fission, which blocks mitobiogenesis. TDP1H493R prompts PTEN-induced kinase 1-dependent mitophagy to eliminate dysfunctional mitochondria. SCAN1-TDP1 in mitochondria creates a pathological state that allows neurons to turn on mitophagy to rescue fit mitochondria as a mechanism of survival.
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Affiliation(s)
- Arijit Ghosh
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sangheeta Bhattacharjee
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Srijita Paul Chowdhuri
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Abhik Mallick
- Department of Chemistry, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pashan, Pune, Maharashtra 411008, India
| | - Ishita Rehman
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sudipta Basu
- Discipline of Chemistry, Indian Institute of Technology (IIT) Gandhinagar, Palaj, Gandhinagar, Gujarat 382355, India
| | - Benu Brata Das
- Laboratory of Molecular Biology, School of Biological Sciences, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India
- Corresponding author.
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Rehman I, Basu SM, Das SK, Bhattacharjee S, Ghosh A, Pommier Y, Das BB. PRMT5-mediated arginine methylation of TDP1 for the repair of topoisomerase I covalent complexes. Nucleic Acids Res 2018; 46:5601-5617. [PMID: 29718323 PMCID: PMC6009676 DOI: 10.1093/nar/gky291] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [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: 06/22/2017] [Revised: 03/18/2018] [Accepted: 04/13/2018] [Indexed: 01/01/2023] Open
Abstract
Human tyrosyl-DNA phosphodiesterases (TDP) hydrolyze the phosphodiester bond between DNA and the catalytic tyrosine of Top1 to excise topoisomerase I cleavage complexes (Top1cc) that are trapped by camptothecin (CPT) and by genotoxic DNA alterations. Here we show that the protein arginine methyltransferase PRMT5 enhances the repair of Top1cc by direct binding to TDP1 and arginine dimethylation of TDP1 at residues R361 and R586. Top1-induced replication-mediated DNA damage induces TDP1 arginine methylation, enhancing its 3'- phosphodiesterase activity. TDP1 arginine methylation also increases XRCC1 association with TDP1 in response to CPT, and the recruitment of XRCC1 to Top1cc DNA damage foci. PRMT5 knockdown cells exhibit defective TDP1 activity with marked elevation in replication-coupled CPT-induced DNA damage and lethality. Finally, methylation of R361 and R586 stimulate TDP1 repair function and promote cell survival in response to CPT. Together, our findings provide evidence for the importance of PRMT5 for the post-translational regulation of TDP1 and repair of Top1cc.
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Affiliation(s)
- Ishita Rehman
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Suparna M Basu
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Subhendu K Das
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Sangheeta Bhattacharjee
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Arijit Ghosh
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
| | - Yves Pommier
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
| | - Benu Brata Das
- Laboratory of Molecular Biology, Department of Biological Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S.C. Mullick Road, Jadavpur, Kolkata 700032, India
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA
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Das SK, Ghosh A, Paul Chowdhuri S, Halder N, Rehman I, Sengupta S, Sahoo KC, Rath H, Das BB. Neutral Porphyrin Derivative Exerts Anticancer Activity by Targeting Cellular Topoisomerase I (Top1) and Promotes Apoptotic Cell Death without Stabilizing Top1-DNA Cleavage Complexes. J Med Chem 2018; 61:804-817. [PMID: 29290109 PMCID: PMC5808360 DOI: 10.1021/acs.jmedchem.7b01297] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
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Camptothecin (CPT) selectively traps
topoisomerase 1-DNA cleavable
complexes (Top1cc) to promote anticancer activity. Here, we report
the design and synthesis of a new class of neutral porphyrin derivative
5,10-bis(4-carboxyphenyl)-15, 20-bis(4-dimethylaminophenyl)porphyrin
(compound 8) as a potent catalytic inhibitor of human
Top1. In contrast to CPT, compound 8 reversibly binds
with the free enzyme and inhibits the formation of Top1cc and promotes
reversal of the preformed Top1cc with CPT. Compound 8 induced inhibition of Top1cc formation in live cells was substantiated
by fluorescence recovery after photobleaching (FRAP) assays. We established
that MCF7 cells treated with compound 8 trigger proteasome-mediated
Top1 degradation, accumulate higher levels of reactive oxygen species
(ROS), PARP1 cleavage, oxidative DNA fragmentation, and stimulate
apoptotic cell death without stabilizing apoptotic Top1-DNA cleavage
complexes. Finally, compound 8 shows anticancer activity
by targeting cellular Top1 and preventing the enzyme from directly
participating in the apoptotic process.
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Affiliation(s)
| | | | | | | | | | - Souvik Sengupta
- Division of Biological and Life Sciences, School of Arts and Sciences, Ahmedabad University , Central Campus, Navrangpura, Ahmedabad, Gujarat 380009, India
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Kumar S, Ahirwar R, Rehman I, Nahar P. Moderate reagent mixing on an orbital shaker reduces the incubation time of enzyme-linked immunosorbent assay. Anal Biochem 2017; 528:53-56. [DOI: 10.1016/j.ab.2017.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 02/10/2017] [Accepted: 04/13/2017] [Indexed: 11/25/2022]
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Maji S, Alam P, Kumar GS, Biswas S, Sarkar PK, Das B, Rehman I, Das BB, Jana NR, Laskar IR, Acharya S. Induced Aggregation of AIE-Active Mono-Cyclometalated Ir(III) Complex into Supramolecular Branched Wires for Light-Emitting Diodes. Small 2017; 13:1603780. [PMID: 28134490 DOI: 10.1002/smll.201603780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 12/21/2016] [Indexed: 06/06/2023]
Abstract
Aggregation-induced emission (AIE) is commonly observed in irregular bulk form. Herein, unique aggregation properties of an AIE-active complex into branched supramolecular wires are reported for the first time. Mono-cyclometalated Ir(III) complex shows in-plane J-aggregation at the air-water interface owing to the restriction of intramolecular vibration of bidentate phenylpyridinato and intramolecular rotations of monodentate triphenylphosphine ligands at air-water interface. As a consequence, a large enhancement of luminescence comparable to the solid state is obtained from the monolayers of supramolecular wires. This unique feature is utilized for the fabrication of light-emitting diodes with low threshold voltage using supramolecular wires as active layer. This study opens up the need of ordered assembly of AIE complexes to achieve optimal luminescence characteristics.
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Affiliation(s)
- Subrata Maji
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Parvej Alam
- Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, 333031, India
| | - Gundam Sandeep Kumar
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Sandip Biswas
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Piyush Kanti Sarkar
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Bidisa Das
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Ishita Rehman
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Benu Brata Das
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Nikhil Ranjan Jana
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
| | - Inamur Rahaman Laskar
- Department of Chemistry, Birla Institute of Technology and Science (BITS), Pilani, Rajasthan, 333031, India
| | - Somobrata Acharya
- Centre for Advanced Materials (CAM), Indian Association for the Cultivation of Science, Jadavpur, Kolkata, 700032, India
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Das SK, Rehman I, Ghosh A, Sengupta S, Majumdar P, Jana B, Das BB. Poly(ADP-ribose) polymers regulate DNA topoisomerase I (Top1) nuclear dynamics and camptothecin sensitivity in living cells. Nucleic Acids Res 2016; 44:8363-75. [PMID: 27466387 PMCID: PMC5041477 DOI: 10.1093/nar/gkw665] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 07/13/2016] [Indexed: 01/19/2023] Open
Abstract
Topoisomerase 1 (Top1) is essential for removing the DNA supercoiling generated during replication and transcription. Anticancer drugs like camptothecin (CPT) and its clinical derivatives exert their cytotoxicity by reversibly trapping Top1 in covalent complexes on the DNA (Top1cc). Poly(ADP-ribose) polymerase (PARP) catalyses the addition of ADP-ribose polymers (PAR) onto itself and Top1. PARP inhibitors enhance the cytotoxicity of CPT in the clinical trials. However, the molecular mechanism by which PARylation regulates Top1 nuclear dynamics is not fully understood. Using live-cell imaging of enhanced green fluorescence tagged-human Top1, we show that PARP inhibitors (Veliparib, ABT-888) delocalize Top1 from the nucleolus to the nucleoplasm, which is independent of Top1–PARP1 interaction. Using fluorescence recovery after photobleaching and subsequent fitting of the data employing kinetic modelling we demonstrate that ABT-888 markedly increase CPT-induced bound/immobile fraction of Top1 (Top1cc) across the nuclear genome, suggesting Top1-PARylation counteracts CPT-induced stabilization of Top1cc. We further show Trp205 and Asn722 of Top1 are critical for subnuclear dynamics. Top1 mutant (N722S) was restricted to the nucleolus in the presence of CPT due to its deficiency in the accumulation of CPT-induced Top1-PARylation and Top1cc formation. This work identifies ADP-ribose polymers as key determinant for regulating Top1 subnuclear dynamics.
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Affiliation(s)
- Subhendu K Das
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Ishita Rehman
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Arijit Ghosh
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Souvik Sengupta
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Papiya Majumdar
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Biman Jana
- Physical Chemistry Department, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
| | - Benu Brata Das
- Laboratory of Molecular Biology, Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A & B, Raja S. C. Mullick Road, Jadavpur, Kolkata-700032, India
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Das BB, Huang SYN, Murai J, Rehman I, Amé JC, Sengupta S, Das SK, Majumdar P, Zhang H, Biard D, Majumder HK, Schreiber V, Pommier Y. PARP1-TDP1 coupling for the repair of topoisomerase I-induced DNA damage. Nucleic Acids Res 2014; 42:4435-49. [PMID: 24493735 PMCID: PMC3985661 DOI: 10.1093/nar/gku088] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Poly(ADP-ribose) polymerases (PARP) attach poly(ADP-ribose) (PAR) chains to various proteins including themselves and chromatin. Topoisomerase I (Top1) regulates DNA supercoiling and is the target of camptothecin and indenoisoquinoline anticancer drugs, as it forms Top1 cleavage complexes (Top1cc) that are trapped by the drugs. Endogenous and carcinogenic DNA lesions can also trap Top1cc. Tyrosyl-DNA phosphodiesterase 1 (TDP1), a key repair enzyme for trapped Top1cc, hydrolyzes the phosphodiester bond between the DNA 3'-end and the Top1 tyrosyl moiety. Alternative repair pathways for Top1cc involve endonuclease cleavage. However, it is unknown what determines the choice between TDP1 and the endonuclease repair pathways. Here we show that PARP1 plays a critical role in this process. By generating TDP1 and PARP1 double-knockout lymphoma chicken DT40 cells, we demonstrate that TDP1 and PARP1 are epistatic for the repair of Top1cc. The N-terminal domain of TDP1 directly binds the C-terminal domain of PARP1, and TDP1 is PARylated by PARP1. PARylation stabilizes TDP1 together with SUMOylation of TDP1. TDP1 PARylation enhances its recruitment to DNA damage sites without interfering with TDP1 catalytic activity. TDP1-PARP1 complexes, in turn recruit X-ray repair cross-complementing protein 1 (XRCC1). This work identifies PARP1 as a key component driving the repair of trapped Top1cc by TDP1.
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Affiliation(s)
- Benu Brata Das
- Developmental Therapeutics Branch and Laboratory of Molecular Pharmacology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-4255, USA, Laboratory of Molecular Biology, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India, Biotechnology and Cell Signaling, UMR7242 CNRS, Université de Strasbourg, Laboratory of Excellence Medalis, ESBS, Blvd Sébastien Brant, CS 10413, 67412 Illkirch, France, CEA-DSV-iMETI-SEPIA, BP6, 92265 Fontenay-aux-Roses cedex, France and Laboratory of Molecular Parasitology, Indian Institute of Chemical Biology, Kolkata 700032, India
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Catto JWF, Yates DR, Rehman I, Azzouzi AR, Patterson J, Sibony M, Cussenot O, Hamdy FC. Behavior of urothelial carcinoma with respect to anatomical location. J Urol 2007; 177:1715-20. [PMID: 17437794 DOI: 10.1016/j.juro.2007.01.030] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2006] [Indexed: 10/23/2022]
Abstract
PURPOSE Urothelial carcinoma is a disease of the entire urothelium. Recent molecular insights suggest that the biology of some upper urinary tract and bladder urothelial carcinoma differ. These differences may affect tumor phenotype. Observational studies conflict as to the significance of anatomical location on the behavior of urothelial carcinoma. We compared the biological outcome in a large series of urothelial carcinoma with respect to anatomical location. MATERIALS AND METHODS We analyzed urothelial carcinoma in 425 patients treated at 4 centers according to stage and anatomical location, including the bladder in 275, the ureter in 67 and the renal pelvis in 79. Relapse surveillance was performed for a median of 46 months (range 2 to 216). A separate invasive bladder urothelial carcinoma population was also included to pathologically balance upper and lower tract urothelial carcinoma cases to allow behavioral comparisons. RESULTS As a whole, upper urinary tract urothelial carcinoma is more invasive and worse differentiated than bladder cancer (chi-square test p<0.0001 and 0.015, respectively). In pathologically matched cohorts recurrence to less aggressive disease, progression to more advanced disease and death occurred in 37%, 40% and 44% of patients with bladder urothelial carcinoma, and in 41%, 44% and 43% of those with upper urinary tract urothelial carcinoma, respectively. Multivariate analysis revealed that tumor stage and grade (Cox p=0.0001 and 0.012, respectively) but not location were associated with behavior. CONCLUSIONS Urothelial carcinoma behaves identically in the upper and lower urinary tracts when stage and grade are considered. The majority of tumors relapse within 5 years of excision. The current move to minimally invasive/nephron sparing techniques for urothelial carcinoma of the upper urinary tract appears safe. Care could be analogous to that for bladder urothelial carcinoma.
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Affiliation(s)
- J W F Catto
- Academic Urology Unit, University of Sheffield, Sheffield, United Kingdom.
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Leiblich A, Cross SS, Catto JWF, Phillips JT, Leung HY, Hamdy FC, Rehman I. Lactate dehydrogenase-B is silenced by promoter hypermethylation in human prostate cancer. Oncogene 2006; 25:2953-60. [PMID: 16547507 DOI: 10.1038/sj.onc.1209262] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In order to identify novel candidates associated with prostate cancer metastasis, we compared the proteomic profile of the poorly metastatic human prostate cancer cell line LNCaP, with its highly metastatic variant LNCaP-LN3, by two-dimensional gel electrophoresis. A major protein spot (pI of 5.9 and molecular weight of 37 kDa) was seen in LNCaP cells, but not in LNCaP-LN3 cells and was identified as lactate dehydrogenase-B (LDHB), by tandem mass spectrometry. Furthermore, enzyme kinetic assays and zymography showed a higher LDH enzyme activity in LNCaP cells compared with LNCaP-LN3. Bisulphite-modified DNA sequencing showed promoter hypermethylation in LNCaP-LN3 cells but not in LNCaP, Du145, PC3, CWR22 or BPH45 cells. Treatment of LNCaP-LN3 cells with 5'-azacytidine caused re-expression of LDHB transcripts. In tissues, LDHB promoter hypermethylation occurred at a higher frequency in prostate cancer, 14/ 31 (45%), compared to adjacent nonmalignant or benign tissue, 2/19 (11%) (P < 0.025). Immunohistochemistry showed a higher frequency of LDHB expression in benign or non-malignant tissues, 59/ 73 (81%), compared to cancer cases, 3/53 (6%) (P < 0.001). Absent LDHB expression was also seen in 7/7 (100%) cases of metastatic cancer in bone. Our data are the first to show loss of LDHB expression in prostate cancer, the mechanism of which appears to involve promoter hypermethylation.
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Affiliation(s)
- A Leiblich
- Academic Urology Unit, Division of Clinical Sciences South, University of Sheffield, UK
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Yates DR, Rehman I, Meuth M, Cross SS, Hamdy FC, Catto JWF. Methylational urinalysis: a prospective study of bladder cancer patients and age stratified benign controls. Oncogene 2006; 25:1984-8. [PMID: 16288222 DOI: 10.1038/sj.onc.1209209] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Tumour suppressor gene (TSG) methylation has been proposed as a diagnostic marker for urothelial cancer (UC). Here, we compare the frequency of urinary TSG methylation in young and elderly patients, with and without UC. Urine samples were obtained prospectively from 35 UC patients, 35 benign controls over the age of 70 years and 34 healthy volunteers under the age of 40 years. Methylation analysis was performed for eight gene promoters using quantitative methylation-specific PCR. Methylation was detected in urine DNA from all three patient groups. The highest frequencies were seen in UC patients. Significantly less methylation was present in control samples than UC cases for RASSF1a and APC (P < 0.034). The 'methylation index' and level of methylation was highest in the UC group and lowest in the young control group. A marker panel of RASSF1a, E-cad and APC generated a sensitivity of 69%, a specificity of 60% and a diagnostic accuracy of 86%. TSG methylation is detectable in urine DNA from patients with and without bladder cancer. The frequency and extent of methylation appears to increase with age and malignancy. The lack of tumour specificity suggests that further investigation is required before this test is introduced into clinical practice.
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Affiliation(s)
- D R Yates
- Institute for Cancer Studies, University of Sheffield, Royal Hallamshire Hospital, Sheffield, UK
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Dhawan D, Hamdy FC, Rehman I, Patterson J, Cross SS, Feeley KM, Stephenson Y, Meuth M, Catto JWF. Evidence for the early onset of aberrant promoter methylation in urothelial carcinoma. J Pathol 2006; 209:336-43. [PMID: 16639696 DOI: 10.1002/path.1991] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [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: 11/10/2022]
Abstract
There is evidence that carcinoma in situ (CIS) is the precursor of invasive urothelial carcinoma, a tumour characterized by frequent gene promoter methylation. The timing of altered DNA methylation is unknown in this pathway. Here we investigate gene methylation in 196 consecutive samples of normal urothelium, CIS, and tumours from 104 patients with both CIS and invasive urothelial carcinoma using quantitative methyl-sensitive polymerase chain reaction for six genes (p16, p14, E-cadherin, RARbeta2, RASSF1a, and GSTP1). Control normal urothelial samples from 15 patients with no history of urothelial carcinoma were also analysed. Immunohistochemistry established the expression of well-characterized CIS markers p53 and cytokeratin 20. Promoter methylation occurred frequently in both normal urothelium and CIS samples from patients with urothelial carcinoma, and increased with progression from normal to invasive urothelial carcinoma, at both specific loci (chi2 test: E-cadherin, p=0.0001; RASSF1a, p=0.003, RARbeta2, p=0.007, p16, p=0.024) and in general (methylation indices [t-test, p<0.0001]). Methylation was associated with cytokeratin 20 expression (t-test, p=0.004) and poor prognosis, and with increased progression to tumour death in patients whose CIS samples showed methylation, in comparison with those without methylation (log rank p<0.03). Promoter methylation occurs early in the urothelial carcinogenic pathway and appears to be a good biomarker of the invasive urothelial carcinoma phenotype.
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Affiliation(s)
- D Dhawan
- Academic Urology Unit, University of Sheffield, and Department of Urology, Royal Hallamshire Hospital, UK
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18
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Rehman I, Azzouzi AR, Catto JWF, Allen S, Cross SS, Feeley K, Meuth M, Hamdy FC. Proteomic analysis of voided urine after prostatic massage from patients with prostate cancer: a pilot study. Urology 2005; 64:1238-43. [PMID: 15596215 DOI: 10.1016/j.urology.2004.06.063] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2004] [Accepted: 06/24/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Serum prostate-specific antigen measurements are widely used for the early detection of prostate cancer but lack specificity, thus warranting the search for additional biomarkers. METHODS Two-dimensional gel electrophoresis followed by matrix-assisted laser desorption ionization-time of flight-mass spectroscopy (MALDI-TOF-MS) analysis was used to investigate the protein profiles of voided urine after prostatic massage from 6 patients with histologically confirmed prostate cancer and 6 age-matched patients with benign prostatic hyperplasia. RESULTS The median number of protein spots per gel was lower in the urine from the patients with cancer (median 143 spots, range 118 to 163) than in the urine from those with benign prostatic hyperplasia (median 154 spots, range 142 to 209), although the difference was not statistically significant. MALDI-TOF-MS analysis identified six commonly expressed proteins: alpha-enolase, isocitrate dehydrogenase, beta-2-microglobulin, alpha-1-microglobulin, complex-forming glycoprotein HC, and PRO2044. Of the five protein spots seen in a subset of patients with cancer, one was identified as calgranulin B/MRP-14. Immunohistochemical staining of prostatic tissue showed greater expression of calgranulin B/MRP-14 in 2 of 7 well-differentiated, 1 of 12 moderately differentiated, and 0 of 8 poorly differentiated tumors relative to adjacent benign tissue; expression of calgranulin A/MRP-8, a heterodermic binding partner of calgranulin B/MRP-14, was absent. CONCLUSIONS The role of urinary calgranulin B/MRP-14 as a potential novel marker for prostate cancer needs additional investigation.
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Affiliation(s)
- I Rehman
- Academic Urology Unit, Division of Clinical Sciences (South), University of Sheffield, Sheffield, United Kingdom
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Cross SS, Hamdy FC, Deloulme JC, Rehman I. Expression of S100 proteins in normal human tissues and common cancers using tissue microarrays: S100A6, S100A8, S100A9 and S100A11 are all overexpressed in common cancers. Histopathology 2005; 46:256-69. [PMID: 15720411 DOI: 10.1111/j.1365-2559.2005.02097.x] [Citation(s) in RCA: 199] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To survey the expression of members of the S100 family of calcium-binding proteins in normal human tissues and common cancers using tissue microarrays. S100A6, S100A8, S100A9 and S100A11 have all been suggested to have potential roles in carcinogenesis and tumour progression but their expression has not been described in a wide range of human tissues and tumours. METHODS AND RESULTS A custom-made tissue array, containing 291 tissue cores representing 28 tissue types and 21 tumour types, was used to produce sections that were immunostained for S100A2, S100A6, S100A8, S100A9, S100A11, calbindin 1, calbindin 2, S100B and parvalbumin. S100A6, S100A8 and S100A9 were expressed in 32%, 12% and 28% of breast cancers, respectively. There was a translocation of S100A11 expression from exclusively nuclear in normal tissues to cytoplasmic and nuclear in all common cancers. CONCLUSIONS S100A6, S100A8, S100A9 and S100A11 are all expressed in common cancers, especially breast cancer. In addition, S100A11 undergoes a nucleocytoplasmic translocation which may have a direct influence on the proliferation of the cancer cells.
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Affiliation(s)
- S S Cross
- Academic Unit of Pathology, Division of Genomic Medicine, School of Medicine and Biomedical Sciences, University of Sheffield, Sheffield, UK.
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20
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Rehman I, Cross SS, Azzouzi AR, Catto JWF, Deloulme JC, Larre S, Champigneuille J, Fromont G, Cussenot O, Hamdy FC. S100A6 (Calcyclin) is a prostate basal cell marker absent in prostate cancer and its precursors. Br J Cancer 2004; 91:739-44. [PMID: 15280928 PMCID: PMC2364790 DOI: 10.1038/sj.bjc.6602034] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
S100A6 (Calcyclin) is a calcium-binding protein that has been implicated in a variety of biological functions as well as tumorigenesis. The aim of our study was to investigate the involvement of S100A6 during prostate cancer development and progression. Using immunohistochemistry, the expression of S100A6 was examined in benign (n=66), premalignant (n=10), malignant (n=66) and metastatic prostate (n=5) tissues arranged in a tissue-microarray or whole sections as well as in prostate cancer cell lines. The S100A6 immunostaining pattern in tissues was compared with that of cytokeratin 5 (a basal cell marker) and 18 (a benign luminal cell marker). In all cases of benign epithelium, intense S100A6 expression was seen in the basal cell layer with absent staining in luminal cells. In all cases of prostatic adenocarcinoma (matched), metastatic lesions and 3/10 high-grade prostatic intraepithelial neoplasia lesions, an absence of S100A6 was seen. Western blotting and RT–PCR analysis of cell lines showed S100A6 expression to be absent in LNCaP, LNCaP-LN3 and LNCaP-Pro5 but present in Du145, PC3, PC-3M and PC-3M-LN4. LNCaP cells treated with 5-Azacytidine, caused re-expression of S100A6 mRNA. Sequencing of bisulphite modified DNA showed CpG methylation within the S100A6 promoter region and exon 1 of LNCaP, LNCaP-LN3 and LNCaP-Pro5 cell lines but not in Du145 cells. Our data suggest that loss of S100A6 protein expression is common in prostate cancer development and may occur at an early stage. The mechanism of loss of expression may involve hypermethylation of CpG sites. The finding of intense S100A6 expression in the basal cells of benign glands but loss of expression in cancer could be useful as a novel diagnostic marker for prostate cancer.
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Affiliation(s)
- I Rehman
- Academic Urology Unit, Division of Clinical Sciences South, University of Sheffield, Floor K, Royal Hallamshire Hospital, Glossop Road, Sheffield S10 2JF, UK.
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Phillips MJ, Darr JA, Luklinska ZB, Rehman I. Synthesis and characterization of nano-biomaterials with potential osteological applications. J Mater Sci Mater Med 2003; 14:875-882. [PMID: 15348525 DOI: 10.1023/a:1025682626383] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The manufacture of high-surface area, un-agglomerated nano-sized (1-100 nm) bioceramic particles are of interest for many applications including injectable/controlled setting bone cements, high strength porous/non-porous synthetic bone grafts, and the reinforcing phase in nano-composites that attempt to mimic the complex structure and superior mechanical properties of bone. In the present study, we report on the manufacture of nano-particle hydroxyapatite powders by several wet chemical methods, which incorporate a freeze-drying step. In particular, it was found that the emulsion-based syntheses yielded powders with high surface areas and small primary particle sizes. Freeze drying rather than oven drying of powders prepared by conventional wet chemical synthesis yielded a nano-sized powder with a comparatively higher surface area of 113 m(2)/g. All powders were calcined in air in a furnace at 900 degrees C to investigate the effects of synthesis method on phase purity and surface area. The materials were characterized by a range of analytical methods including Fourier-transform infrared spectroscopy employing the photo acoustic (PAS-FTIR) sampling technique, BET surface area analysis, X-ray powder diffraction (XRD), and the particles were examined using a transmission electron microscope (TEM).
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Affiliation(s)
- M J Phillips
- Interdisciplinary Research Centre in Biomedical Materials, Department of Materials, Queen Mary, University of London, Mile End Road, London, E1 4NS, UK
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22
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Kathirvel S, Chavan S, Arya VK, Rehman I, Babu V, Malhotra N, Bhukal I, Chari P. Anesthetic management of patients with Takayasu's arteritis: a case series and review. Anesth Analg 2001; 93:60-5. [PMID: 11429340 DOI: 10.1097/00000539-200107000-00014] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [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: 11/25/2022]
Abstract
UNLABELLED Takayasu's arteritis is a rare, chronic progressive panendarteritis involving the aorta and its main branches. Anesthesia for patients with Takayasu's arteritis is complicated by their severe uncontrolled hypertension, end-organ dysfunction resulting from hypertension, stenosis of major blood vessels affecting regional circulation, and difficulties encountered in monitoring arterial blood pressure. Takayasu's arteritis is an uncommon disease and previous descriptions of the anesthetic management of patients with this disease have been limited to isolated case reports in the anesthetic literature, mostly in women undergoing cesarean delivery. We present our experience in this series of eight patients for various emergency and elective surgical procedures and review their perioperative problems and management. IMPLICATIONS This case series describes the anesthetic problems and management of patients with pulseless disease.
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Affiliation(s)
- S Kathirvel
- Department of Anesthesiology and Critical Care, Postgraduate Institute of Medical Education and Research, Chandigarh-160012, India.
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23
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Murton NJ, French L, Toomes C, Joseph SS, Rehman I, Hopkins BL, Inglehearn CF, Churchill AJ. A high-density transcript map of the human dominant optic atrophy OPA1 gene locus and re-evaluation of evidence for a founder haplotype. Cytogenet Cell Genet 2001; 92:97-102. [PMID: 11306804 DOI: 10.1159/000056876] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dominant optic atrophy (DOA, gene OPA1) is the commonest form of inherited optic atrophy. Linkage studies have shown that a locus for this disease lies in a 1.4-cM region at chromosome 3q28-->q29 and have suggested a founder haplotype for as many as 95% of the linked families. To aid the identification of candidate genes for this disease, we have constructed a Bacterial Artificial Chromosome (BAC) contig covering approximately 3.3 Mb and encompassing the OPA1 critical region (flanking markers D3S3669 and D3S3562). This physical map corrects errors in the marker order reported in the literature, allowing the OPA1 critical region to be precisely defined. A reassessment of the founder effect in the light of the revised marker order suggests that it may not be as significant as had previously been suggested. A high-density transcript map was created by precisely mapping genes and expressed sequence tags (ESTs) from GeneMap'99, that have been loosely assigned to the region by radiation hybrid mapping. One known gene (KIAA0567 protein) and 15 ESTs were found to lie within the minimal disease region. Analysis of the sequence data already available from within the OPA1 critical region allowed the identification and mapping of a further 31 ESTs. The work presented in this study provides the basis for the characterisation of candidate genes and the ultimate identification of the gene mutated in DOA.
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Affiliation(s)
- N J Murton
- Molecular Medicine Unit, St. James's University Hospital, Leeds, UK
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24
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Gibson IR, Rehman I, Best SM, Bonfield W. Characterization of the transformation from calcium-deficient apatite to beta-tricalcium phosphate. J Mater Sci Mater Med 2000; 11:799-804. [PMID: 15348063 DOI: 10.1023/a:1008905613182] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The structural changes that occur during the transformation of a Ca-deficient apatite, prepared by a wet chemical method, to beta-TCp were investigated. X-ray diffraction (XRD) analysis of as-prepared samples and samples calcined at temperatures between 500 and 1100 degrees C showed that the transformation occurs over the temperature range 710-740 degrees C, under non-equilibrium conditions. The change in crystallite size with increasing calcination/sintering temperature was studied by XRD using the Scherrer formula. Fourier transform infra-red (FTIR) analysis indicated considerable structural change in samples above and below this temperature range. Changes were observed in the hydroxyl, carbonate and phosphate bands as the calcination temperature was increased from 500 to 1100 degrees C. Even once a single beta-TCP phase is obtained at 740 degrees C there remains a considerable amount of structural change at temperatures between 740 and 1100 degrees C. This effect was illustrated by an unusual change in the lattice parameters of the beta-TCP structure and significant changes in the phosphate bands of FTIR spectra as the calcination temperature was increased. The results obtained in this study show that the combined experimental techniques of XRD and FTIR are excellent complimentary methods for characterizing structural changes that occur during phase transformations.
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Affiliation(s)
- I R Gibson
- IRC in Biomedical Materials, Queen Mary and Westfield College, Mile End Road, London, E1 4NS, UK
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25
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Gibson IR, Rehman I, Best SM, Bonfield W. Characterization of the transformation from calcium-deficient apatite to beta-tricalcium phosphate. J Mater Sci Mater Med 2000; 11:533-539. [PMID: 15348382 DOI: 10.1023/a:1008961816208] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The structural changes that occur during the transformation of a Ca-deficient apatite, prepared by a wet chemical method, to beta-TCP were investigated. X-ray diffraction (XRD) analysis of as-prepared samples and samples calcined at temperatures between 500 and 1100 degrees C showed that the transformation occurs over the temperature range 710-740 degrees C, under non-equilibrium conditions. The change in crystallite size with increasing calcination/sintering temperature was studied by XRD using the Scherrer formula. Fourier transform infra-red (FTIR) analysis indicated considerable structural change in samples above and below this temperature range. Changes were observed in the hydroxyl, carbonate and phosphate bands as the calcination temperature was increased from 500 to 1100 degrees C. Even once a single beta-TCP phase is obtained at 740 degrees C there remains a considerable amount of structural change at temperatures between 740 and 1100 degrees C. This effect was illustrated by an unusual change in the lattice parameters of the beta-TCP structure and significant changes in the phosphate bands of the FTIR spectra as the calcination temperature was increased. The results obtained in this study show that the combined experimental techniques of XRD and FTIR are excellent complimentary methods for characterizing structural changes that occur during phase transformations.
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Affiliation(s)
- I R Gibson
- IRC in Biomedical Materials, Queen Mary and Westfield College, Mile End Road, London, E1 4NS, UK.
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26
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García F, Arias JL, Mayor B, Pou J, Rehman I, Knowles J, Best S, León B, Pérez-Amor M, Bonfield W. Effect of heat treatment on pulsed laser deposited amorphous calcium phosphate coatings. J Biomed Mater Res 2000; 43:69-76. [PMID: 9509346 DOI: 10.1002/(sici)1097-4636(199821)43:1<69::aid-jbm8>3.0.co;2-k] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Amorphous calcium phosphate coatings were produced by pulsed laser deposition from targets of nonstoichiometric hydroxyapatite (Ca/P = 1.70) at a low substrate temperature of 300 degrees C. They were heated in air at different temperatures: 300, 450, 525 and 650 degrees C. Chemical and structural analyses of these coatings were performed using X-ray diffraction (XRD), FTIR, and SEM, XRD analysis of the as-deposited and heated coatings revealed that their crystallinity improved as heat treatment temperature increased. The main phase was apatitic, with some beta-tricalcium phosphate in the coatings heated at 525 and 600 degrees C. In the apatitic phase there was some carbonate substitution for phosphate and hydroxyl ions at 450 degrees C and almost solely for phosphate at 525 and 600 degrees C as identified by FTIR. This was accompanied by a higher hydroxyl content at 525 and 600 degrees C. At 450 degrees C a texture on the coating surface was observable by SEM that was attributable to a calcium hydroxide and calcite formation by XRD. These phases almost disappeared at 600 degrees C, probably due to a transformation into calcium oxide.
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Affiliation(s)
- F García
- Departamento de Física Aplicada, Universidade de Vigo, Spain
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27
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Affiliation(s)
- N J Murton
- Molecular Medicine Unit, Clinical Sciences Building, St. James's University Hospital, Leeds, LS9 7TF, UK
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28
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Abstract
A nucleation and crystallization schedule was adapted to produce 40% crystalline Bioglass ceramic particulates. These particles were placed in a dynamic environment in a simulated physiologic solution (SBF-9) for time periods ranging from 10 min to 7 days. Fourier transform Raman spectroscopy (FT-Raman) and infrared spectroscopy (FTIR) were used to analyze the apatite layer formation on the particulates. FTIR determined that amorphous apatite formation took place within 2 h, with the appearance of crystalline apatite in 14 h. The vibrational frequencies obtained through FT-Raman were equivalent to those obtained using FTIR. These analyses showed that a fully crystallized apatite layer was present on the particulate after 3 days of exposure in SBF solution. These findings are consistent with those associated with amorphous Bioglass particles.
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Affiliation(s)
- I Rehman
- Interdisciplinary Research Centre in Biomedical Materials, Queen Mary & Westfield College, University of London, Mile End Road, London E1 4NS, United Kingdom.
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29
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Rehman I, Lowry DT, Adams C, Abdel-Fattah R, Holly A, Yuspa SH, Hennings H. Frequent codon 12 Ki-ras mutations in mouse skin tumors initiated by N-methyl-N'-nitro-N-nitrosoguanidine and promoted by mezerein. Mol Carcinog 2000; 27:298-307. [PMID: 10747294] [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: 02/16/2023]
Abstract
The skin tumor initiators N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 7,12-dimethylbenz[a]anthracene (DMBA) differ in effectiveness when tumor formation is promoted by 12-O-tetradecanoylphorbol-13-acetate (TPA). Even at high doses, MNNG is less effective, producing fewer benign and malignant tumors with a longer latent period. In DMBA-initiated skin, 10 wk of TPA promotion produced a maximal tumor response. With MNNG, 20 wk of TPA promotion was required, producing nearly four times as many papillomas as 10 wk of promotion. Promotion of MNNG-initiated skin with mezerein induced the appearance of very rapidly-growing papillomas within 5 wk, 3 wk earlier than the first TPA-promoted papillomas. Thus, MNNG may induce a novel mutation resulting in a population of initiated cells that respond especially well to mezerein. Since ras mutations are common in experimental tumors in many tissues, we determined the frequency of activating mutations in the Ha-ras, Ki-ras, and N-ras oncogenes. Activating Ha-ras mutations were present in essentially all DMBA-initiated tumors and about 70% of MNNG-initiated tumors. No N-ras mutations were found in tumors lacking other ras mutations. Surprisingly, 41% of the papillomas arising in the first 11 wk in MNNG-initiated, mezerein-promoted mice bore mutations in codon 12 of the Ki-ras oncogene. Activating Ki-ras mutations were also found in more than 60% of squamous cell carcinomas and 40% of keratoacanthomas. Although mutations in Ha-ras are frequently detected in mouse skin tumors, mutations in Ki-ras are rare. This is the first report of mutated Ki-ras in skin tumors from mice initiated by MNNG.
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Affiliation(s)
- I Rehman
- Laboratory of Cellular Carcinogenesis and Tumor Promotion, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892-4255, USA
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Abstract
p21WAF is a cyclin-dependent kinase inhibitor which is widely expressed in epidermal structures. Using a combination of double immunocytochemical staining and combined in situ hybridization, we show that there is a striking exclusivity between the expression of Ki67 and p21WAF in the hair matrix. Some cells that are Ki67-positive also express p53, but as they exit the cell cycle they assume p21WAF-positive/p53-negative status. By contrast, cells in the interfollicular epidermis of psoriatic lesions, in the sebaceous gland, and in the outer root sheath are p21WAF-positive/p53-positive but Ki67-negative. These results suggest that in some anatomical parts of the epidermis, p21WAF expression can accompany p53 expression, whereas in other parts, the expression of these markers is reciprocal, suggesting that other pathways may be controlling p21WAF expression. In order to define, functionally, the presence of p53-independent p21WAF expression in skin, we examined lesions of Bowen's disease in which both alleles of p53 were inactivated. p21WAF expression was still observed, confirming a role for p53-independent expression of p21WAF in human skin in vivo.
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Affiliation(s)
- Y Y Wu
- Department of Dermatology, Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK
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Abstract
Fourier transform infrared spectroscopy and thin-film X-ray diffraction (TF-XRD) techniques were used to analyze the inorganic carbonate apatite (CA) layer developed on a bioactive glass (45S5 type Bioglass) in an in vitro environment. The C-O and P-O vibrational modes appeared on the bioactive glass surface following immersion in the simulated body fluid solution. Initially, the C-O and P-O peaks increased with immersion time as crystallization of CA phase progressed. The TF-XRD confirmed that the deposited layer was apatite, crystallographically. Furthermore, evidence of preferred orientation in the 001 direction was seen, indicated by very strong 002 reflection. With time, the crystal growth became more random and the intensity of the 002 reflection decreased.
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Affiliation(s)
- I Rehman
- IRC in Biomedical Materials, Queen Mary and Westfield College, London, UK
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Abstract
Skin tumors induced in mice by initiation-promotion (2 microg DMBA-2 microg TPA) protocols were found to be under multigenic control. Eighty-one N2 mice from the cross (BALB/cAnPt x SENCARA/Pt)F1 x SENCARA/Pt that were either solidly resistant (no papillomas) or highly susceptible (> or = 7 papillomas/mouse) were subjected to a 'genome scan' using 89 microsatellite markers to check for associations with susceptible and resistant phenotypes. A locus on Chr 5 (Skts4) was found to control the susceptibility of SENCARA/Pt mice and the resistance of BALB/cAnPt mice to papilloma formation. In addition, higher than expected linkage scores were seen for the markers D9Mit271, D11Mit268 and D12Mit56. Further work is required to establish whether genes determining papilloma formation are located in these regions of the genome. In general, no evidence was seen for loss of heterozygosity in microsatellite markers on Chrs 5, 9 and 11 in 17 microdissected papillomas from (BALB/c x SENCARA)F1 hybrid mice.
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Affiliation(s)
- B A Mock
- Laboratory of Genetics, DBS, NCI, National Institutes of Health, Bethesda, MD 20892-4255, USA
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Takata M, Rehman I, Rees JL. A trichilemmal carcinoma arising from a proliferating trichilemmal cyst: the loss of the wild-type p53 is a critical event in malignant transformation. Hum Pathol 1998; 29:193-5. [PMID: 9490283 DOI: 10.1016/s0046-8177(98)90234-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The genetic events responsible for tumor progression may be defined by careful analysis of genetic changes in well-chosen tumors which contain distinct cell populations representing each stage of progression. Here we report a case of a trichilemmal carcinoma arising in the wall of a proliferating trichilemmal cyst (PTC). DNA was isolated from microdissected areas of the PTC and the carcinoma respectively, and PCR-based microsatellite loss of heterozygosity (LOH) analysis as well as p53 gene sequencing performed. A CGA to TGA nonsense mutation at codon 306 in exon 8 of the p53 gene was found in both samples. LOH analysis showed that the PTC retained chromosome arm 17p (where the p53 gene resides), whereas the carcinoma was associated with the loss of this allele. All the other loci examined were retained including 3p, 9q, 13q and 17q in both tumor parts. The results confirm a common clonal origin of the PTC and the trichilemmal carcinoma, and strongly suggest that the complete loss of the wild-type p53 is a critical event responsible for malignant transformation in this particular case.
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Affiliation(s)
- M Takata
- Department of Dermatology, Kanazawa University School of Medicine, Japan
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Huang J, Di Silvio L, Wang M, Rehman I, Ohtsuki C, Bonfield W. Evaluation of in vitro bioactivity and biocompatibility of Bioglass-reinforced polyethylene composite. J Mater Sci Mater Med 1997; 8:809-813. [PMID: 15348796 DOI: 10.1023/a:1018581100400] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The bioactivity and biocompatibility of Bioglass-reinforced high-density polyethylene composite (Bioglass/HDPE) have been evaluated in simulated body fluid (SBF) and by in vitro cell culture, respectively. The formation of a biologically active hydroxy-carbonate apatite (HCA) layer on the composite surface after immersion in SBF was demonstrated by thin-film X-ray diffraction, infrared spectroscopy and scanning electron microscopy, indicating the in vitro bioactivity of Bioglass/HDPE composites. The HCA layer was formed on the 40 vol% composite surface within 3 days immersion in SBF at a formation rate comparable to those on bioactive glass-ceramics, showing that in vitro bioactivity could be obtained in a composite. Furthermore, the composite was biocompatible to primary human osteoblast-like cells. In comparison with unfilled HDPE and tissue culture plastic control, a significant increase in cellular metabolic activity was found on the composite. Therefore, Bioglass/HDPE composites have a promising biological response as a potential implant material.
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Affiliation(s)
- J Huang
- IRC in Biomedical Materials, Queen Mary and Westfield College, Mile End Road, London E1 4NS, UK
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Sikkink SK, Rehman I, Rees JL. Deletion mapping of chromosome 3p and 13q and preliminary analysis of the FHIT gene in human nonmelanoma skin cancer. J Invest Dermatol 1997; 109:801-5. [PMID: 9406824 DOI: 10.1111/1523-1747.ep12340991] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [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: 02/05/2023]
Abstract
Loss of heterozygosity of chromosomes 3p and 13q occurs frequently in human cutaneous squamous cell neoplasms, suggesting the presence of one or more tumor suppressor genes on these chromosome arms that may be involved in the pathogenesis of this tumor type. To date there is no clear evidence in cutaneous tumors where these putative genes are located. In this study we have analyzed 20 squamous cell neoplasms that show allelic loss at chromosome 13q, and 22 squamous cell neoplasms that show allelic loss at chromosome 3p, in an attempt to define the smallest area of deletion. One commonly deleted region was identified on chromosome 13 that centred around 13q13, and two commonly deleted regions were identified on chromosome 3 that mapped to 3p24-pter and 3p12-p14.1. Our findings suggest the presence of at least one tumor suppressor gene on chromosome 13 and two tumor suppressor genes on chromosome 3p that may be involved in the progression of these neoplasms. Deletions within the Fragile Histidine Triad gene, located at 3p14.2, have been reported in several tumors, leading to the suggestion that this gene is involved in tumor development. To evaluate the role of the Fragile Histidine Triad gene in nonmelanoma skin cancer, we have used reverse transcriptase polymerase chain reaction analysis to screen for deletions in 16 tumors (five basal cell carcinomas, five squamous cell carcinomas, five actinic keratoses, and one case of Bowen's disease) and HaCaT and A431 cell lines. A normal transcript was found to be expressed in 14 of 16 tumors and both cell lines. This suggests that the Fragile Histidine Triad gene is not a common target for deletion in Bowen's disease and the cell lines HaCaT and A431.
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Affiliation(s)
- S K Sikkink
- Department of Dermatology, University of Newcastle upon Tyne, UK
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36
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Abstract
The Japanese have a much lower incidence of nonmelanoma skin cancers (NMSCs) than Caucasians, presumably due in part to their skin type conferring relative protection from ultraviolet light radiation (UVR). To examine the contribution of environmental or endogenous mutagens other than UVR, which are expected to be relatively more important to the overall burden of NMSCs in the Japanese, we directly sequenced exons 5-8 of the p53 tumour suppressor gene in 29 Japanese patients with Bowen's disease, an in situ squamous-cell carcinoma of the skin. We found 9 mutations, including two CC:GG to TT:AA tandem transitions (presumably related to UVR), 3 transversions and 4 frameshift mutations. The mutational spectrum seen in our study contrasts with that we previously found in Bowen's disease from a Caucasian population, in keeping with a different aetiology for Bowen's disease in the respective populations. The unexpectedly high prevalence of frameshift mutations suggests that environmental mutagens other than UVR that preferentially induce deletion or insertion mutations may play an important role in the tumorigenesis of Japanese Bowen's disease, and warrants further investigation.
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Affiliation(s)
- M Takata
- Department of Dermatology, University of Newcastle upon Tyne, UK.
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Jha LJ, Best SM, Knowles JC, Rehman I, Santos JD, Bonfield W. Preparation and characterization of fluoride-substituted apatites. J Mater Sci Mater Med 1997; 8:185-191. [PMID: 15348758 DOI: 10.1023/a:1018531505484] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Apatites were prepared with three different fluoride concentrations: 0.0 mM (pure hydroxyapatite) 2.5 mM and 5 mM. Reactions were performed in aqueous medium using a reaction between diammonium orthophosphate and calcium nitrate 4-hydrate and ammonium fluoride at temperatures of 3 degrees, 25 degrees, 60 degrees and 90 degrees C. The effects of reaction temperature and fluoride concentration on the crystal morphology, phase purity and crystallinity of the precipitates were observed, using transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and ion chromatography. Transmission electron micrographs revealed that the crystallites precipitated at 3 degrees C were spheroidal, but became increasingly acicular with increasing precipitation temperature. X-ray diffraction results indicated that all the materials produced were phase pure and that the crystallinity of apatites prepared at higher precipitation temperatures was higher than those prepared at lower precipitation temperatures. A significant difference in the a-axis dimension of fluoride-substituted apatites was observed, as compared to hydroxyapatite. FTIR spectroscopy revealed a hydroxyl band at 3568 cm-1, along with a broad peak of adsorbed water in the region of 3568 cm-1 to 2670 cm-1 in the hydroxyapatite and fluoride-substituted apatite powders. Hence by careful selection of the precipitation conditions and fluoride contents, the composition and morphology of fluoride-substituted apatite may be controlled and this has interesting implications for the development of these materials for biomedical implantation.
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Affiliation(s)
- L J Jha
- National Institute of Biomedical Engineering, Porto, Portugal
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Abstract
An understanding of the interfacial relationship between a bioceramic implant and the adjacent bone tissue is facilitated by precise characterization of the associated structures. The structure of different commercial synthetic hydroxyapatite powders and a novel carbonated apatite have been studied with photo-acoustic (PAS) Fourier transform infrared (FTIR) spectroscopy. The PAS technique is an ideal method for analysing biomaterials, as materials can be analysed without the need to reduce the particle size or to dilute with KBr. Spectra from carbonated apatite appear to be different from those of commercial hydroxyapatite powders, with the main difference lying in the carbonate and phosphate ratio. Commercial hydroxyapatite powders from different sources have also been analysed and compared.
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Affiliation(s)
- I Rehman
- IRC in Biomedical Materials, Queen Mary and Westfield College, University of London, Mile End Road London E1 4NS UK
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39
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Abstract
Organ transplant recipients receiving immunosuppression show a dramatically increased risk of non-melanoma skin cancer. The cause of this increase is not known. We report that the rate of loss of heterozygosity (at all the loci we examined) was significantly lower in tumours from immunosuppressed individuals than in tumours from immunocompetent subjects [20 out of 148 (14%) vs 157 out of 428 (37%); P< 0.0001]. These results suggest that tumours in immunosuppressed individuals have a different molecular pathogenesis.
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Affiliation(s)
- I Rehman
- Department of Dermatology, University of Newcastle upon Tyne, UK
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40
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Abstract
A method has been developed which enables an in situ analysis of the degree of polymerization of bone cement. The concentration of monomeric double bond is monitored continuously during the entire curing process and hence the method can be used for quantitative studies of polymerization kinetics. In this study, Fourier Transform Raman (FTR) spectroscopy was utilized to investigate the degree of polymerization of a novel bone cement in situ, and the results are compared with the thermal profile obtained for polymerization.
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Affiliation(s)
- I Rehman
- Queen Mary and Westfield College, University of London, UK
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41
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Rehman I, Takata M, Wu YY, Rees JL. Genetic change in actinic keratoses. Oncogene 1996; 12:2483-90. [PMID: 8700506] [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: 02/01/2023]
Abstract
Actinic keratoses (AKs) are small scaly red areas of skin characterised histologically by dysplasia, a minority of which are thought to be precursors of squamous cell carcinoma (SCC), and which show a high frequency of regression. Surprisingly, in view of their benign clinical course, they show a high frequency of loss of heterozygosity (LOH) with a median loss of four loci with almost 20% of lesions showing loss of eight or more alleles, as well as frequent p53 mutation. Loss was common on 3p (31%), 9p (39%), 9q (22%), 13q (52%), 17p (64%) and 17q (46%), and allele loss correlated with dysplasia. Topological disturbance of p21WAF1/CIP1 expression correlated with allele loss but was also seen together with increased wild-type p53 expression and an increase in the fraction of cycling cells in the absence of allele loss or p53 mutation, and is likely to represent an early change. P21WAF1/CIP1 expression appeared independent of p53 status. The frequency of LOH in AKs exceeded that of (invasive) SCCs suggesting that the relation between the accumulation of genetic change and behaviour for non-melanoma skin cancer is not straightforward.
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Affiliation(s)
- I Rehman
- Department of Dermatology, University of Newcastle upon Tyne, UK
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Waring AJ, Takata M, Rehman I, Rees JL. Loss of heterozygosity analysis of keratoacanthoma reveals multiple differences from cutaneous squamous cell carcinoma. Br J Cancer 1996; 73:649-53. [PMID: 8605102 PMCID: PMC2074334 DOI: 10.1038/bjc.1996.113] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Keratoacanthomas (KAs) resemble squamous cell carcinomas (SCCs) except that, unlike SCCs, after a period of rapid growth over a few months they involute completely. The basis of their regressing natural history is not known. We have examined keratoacanthomas and another benign cutaneous tumour, the basal cell papilloma (BCP), for loss of heterozygosity (LOH) at a number of loci that are frequently lost in SCCs and other skin tumours. The frequency of LOH for both KAs and BCPs was low, with only isolated losses identified at 9p, 9q and 10q in KAs [fractional allelic loss (FAL) was 1.3%], and at 9p and 17p in BCPs (FAL was 0.4%). This contrasts with previous work showing a FAL of 32% in SCC and 46% in actinic keratoses. The results show a clear difference between KA and SCC and do not support the hypothesis that KAs are SCCs that regress as a result of external (host) influences but rather suggest that KAs and SCCs are different de novo. LOH around the locus implicated in the multiple self-healing epitheliomata of Ferguson-Smith (9q22-q31) was shown in only 1 of 11 KAs.
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Affiliation(s)
- A J Waring
- Department of Dermatology, University of Newcastle upon Tyne, UK
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Healy E, Belgaid CE, Takata M, Vahlquist A, Rehman I, Rigby H, Rees JL. Allelotypes of primary cutaneous melanoma and benign melanocytic nevi. Cancer Res 1996; 56:589-93. [PMID: 8564976] [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: 01/31/2023]
Abstract
A multistep genetic model of tumorigenesis, based on genetic alterations in benign and primary malignant lesions, has been proposed for neoplasms such as colonic carcinoma. However, evidence for a similar genetic progression in melanoma has relied heavily on findings in cultured lesions or metastases. We have investigated every autosomal arm for loss of heterozygosity in 41 primary cutaneous melanomas and 32 benign melanocytic nevi, and have investigated several chromosome arms that show loss in melanoma in 27 Spitz nevi (a nevus with histological similarities to melanoma). Loss of heterozygosity in primary melanoma was identified most frequently on chromosomes 9p (46%) at loci near the p16INK4 gene, 10q (31%), 6q (31%), and 18q (22%); loss of these chromosome arms were related to the progression of the melanoma. Only two benign melanocytic nevi (both of which showed atypical features on histology) demonstrated genetic alterations, including p9 loss in one case. In addition, two Spitz nevi contained interstitial deletions on chromosome 9p. Our findings show that loss of heterozygosity of 9p is not confined to melanoma, but that other uncultured melanocytic lesions can also display loss of this chromosome arm, and that other genetic changes (e.g., loss of 10q, 6q, and 18q) may be important in conveying the malignant phenotype to melanoma.
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Affiliation(s)
- E Healy
- Department of Dermatology, University of Newcastle upon Tyne, United Kingdom
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Rehman I, Smith R, Hench LL, Bonfield W. Structural evaluation of human and sheep bone and comparison with synthetic hydroxyapatite by FT-Raman spectroscopy. J Biomed Mater Res 1995; 29:1287-94. [PMID: 8557731 DOI: 10.1002/jbm.820291016] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The composition of whole human and sheep cortical bone tissue, and of a synthetic hydroxyapatite (P120), were compared using Fourier transform Raman (FT-Raman) spectroscopy. Deproteination procedures to remove the bulk of the collagen present in bone tissue allowed isolation of the mineral phase. A comparison of the spectra obtained from both whole and deproteinated bone with those of synthetic hydroxyapatite showed direct correlation only in the region of 952 cm-1 (symmetric P-O mode). In contrast, human and sheep bone were very closely matched in both, the organic and inorganic structures. The results demonstrate that deproteination of bone is not a necessary precursor to obtain spectral information.
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Affiliation(s)
- I Rehman
- Interdisciplinary Research Centre in Biomedical Materials, Queen Mary and Westfield College, University of London, United Kingdom
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Abstract
Microsatellite instability secondary to replication errors (RER), characterized by length changes at repetitive loci scattered throughout the genome, is a recently recognized genetic mechanism important in the development of some human cancers. Although RER has been reported in sebaceous gland tumors from patients with the Muir-Torre syndrome, the frequency of RER in human non-melanoma and melanoma skin cancers is not known. In this study, we investigated the importance of RER in human skin carcinogenesis. RER was identified in three of four actinic keratoses from a patient belonging to a kindred with documented Muir-Torre syndrome, which indicates that defective DNA replication may contribute to skin cancer development in such patients. Examination of a series of tumors from patients without Muir-Torre, including 137 skin cancers (47 basal cell carcinomas, 49 squamous cell carcinomas, and 41 primary malignant melanomas), 19 actinic keratoses, and 20 cases of Bowen's disease, using 10 or more microsatellite markers, identified repeat-sequence instability in less than 5% of the tumors studied. In six of the eight tumors, the sole change was an alteration 2 base pairs in length at a single locus. One patient with a squamous cell carcinoma showed changes at multiple loci suggesting defective mismatch repair. Although the low frequency of RER found in this study of a large series of human skin tumors suggests that this phenomenon is uncommon in patients with skin cancer, the identification of RER at multiple loci in two patients suggests that error-prone replication may be important in skin cancer development in some individuals.
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Affiliation(s)
- A G Quinn
- Department of Dermatology, University of Newcastle upon Tyne, Royal Victoria Infirmary, United Kingdom
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Abstract
Difficulties in obtaining clinical samples from primary melanomas have meant that most genetic analyses of melanoma have concentrated on cell lines and metastases. Because the Breslow thickness of the primary tumour is the single best prognostic indicator, it is important to identify genetic abnormalities in primary melanomas and relate these changes to the thickness of the lesion. We have investigated 47 sporadic melanomas, of which 41 were primary lesions, for loss of heterozygosity (LOH) on several chromosomal arms, including areas where genes involved in familial melanoma and other relevant hereditary syndromes map, and where LOH has previously been reported in cell lines, or metastatic lesions. LOH was identified at 66 (18%) of 358 informative loci in primary melanomas, and there was a significant relationship between the overall frequency of LOH and Breslow thickness (P < 0.0005). Loss of chromosome arm 9p was most frequent, occurring in 15 (47%) of 32 informative primary tumours, and was observed in 3 of 11 informative lesions < or = 1.5 mm in depth. LOH on chromosome arms 3p, 6q, 10q, 11q, and 17p was also relatively frequent, with loss of 3p and 10q heterozygosity in lesions < or = 1.5 mm in depth, while LOH on 6q, 11q, and 17p was only detected in more invasive tumours. The results suggest that loss of these chromosome regions are important in sporadic cutaneous melanoma, and are consistent with chromosome arm 9p loss occurring before loss of other chromosome arms.
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Affiliation(s)
- E Healy
- Department of Dermatology, University of Newcastle upon Tyne, United Kingdom
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48
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Abstract
Actinic keratoses (AKs) are focal areas of dysplasia with low risk of progression to squamous cell cancer; many regress spontaneously. Using polymerase-chain-reaction microsatellite analysis, we found that loss of heterozygosity on several chromosome arms, including 17p, 17q, 9p, 9q, and 13q, was common in AKs. More than half the AKs examined showed loss of heterozygosity at four or more loci. The apparent genetic instability of these lesions contrasts with their benign clinical course.
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MESH Headings
- Alleles
- Carcinoma, Squamous Cell/etiology
- Carcinoma, Squamous Cell/genetics
- Chromosomes, Human, Pair 13
- Chromosomes, Human, Pair 17
- Chromosomes, Human, Pair 9
- DNA, Satellite/analysis
- Gene Deletion
- Genes, Tumor Suppressor
- Genes, p53
- Genetic Markers
- Heterozygote
- Humans
- Keratosis/genetics
- Polymerase Chain Reaction
- Precancerous Conditions/genetics
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Affiliation(s)
- I Rehman
- University Department of Dermatology, Royal Victoria Infirmary, Newcastle upon Tyne, UK
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Abstract
FT-Raman spectroscopy proves to be a powerful technique to study surface reactions on bioactive glasses and it eliminates the fluorescence of the organic phase of whole bone, thereby making it possible to compare the reaction layers formed on bioactive glasses with the mineral phase of bone. The spectrum of hydroxycarbonate apatite (HCA) developed on the bioactive glasses is closer to that of bone than synthetic hydroxyapatite (HA) and closely matches that of bone mineral obtained by deproteination of whole human femoral cortical bone.
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Affiliation(s)
- I Rehman
- Interdisciplinary Research Centre in Biomedical Materials, Queen Mary and Westfield College, University of London, UK
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Rehman I, Bell K. Audiovisual criteria in the teaching of the morphological sciences. J Biol Photogr Assoc 1973; 41:91-5. [PMID: 4126146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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