1
|
Molecular changes consistent with increased proliferation and invasion are common in rectal cancer. Clin Transl Oncol 2011; 13:753-9. [DOI: 10.1007/s12094-011-0728-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
2
|
Zhao X, Pan F, Yaseen M, Lu JR. Molecular biophysics underlying gene delivery. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/b903512p] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
3
|
Laurence JM, Allen RDM, McCaughan GW, Logan GJ, Alexander IE, Bishop GA, Sharland AF. Gene therapy in transplantation. Transplant Rev (Orlando) 2009; 23:159-70. [PMID: 19428235 DOI: 10.1016/j.trre.2009.04.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Gene therapy is an exciting and novel technology that offers the prospect of improving transplant outcomes beyond those achievable with current clinical protocols. This review explores both the candidate genes and ways in which they have been deployed to overcome both immune and non-immune barriers to transplantation success in experimental models. Finally, the major obstacles to implementing gene therapy in the clinic are considered.
Collapse
Affiliation(s)
- Jerome M Laurence
- Collaborative Transplantation Research Group, Bosch Insitute, Royal Prince Alfred Hospital and University of Sydney, NSW 2006, Australia
| | | | | | | | | | | | | |
Collapse
|
4
|
Quan J, Tan PH, MacDonald A, Friend PJ. Manipulation of indoleamine 2,3-dioxygenase (IDO) for clinical transplantation: promises and challenges. Expert Opin Biol Ther 2009; 8:1705-19. [PMID: 18847306 DOI: 10.1517/14712598.8.11.1705] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Since the discovery that indoleamine 2,3-dioxygenase (IDO) is a modulator for maintenance of fetomaternal immuno-privilege state, it has been implicated in tumour tolerance, autoimmune diseases and asthma. IDO is an IFN-gamma-inducible, intracellular enzyme that catalyzes the initial and rate-limiting step in the degradation of tryptophan. It has been suggested that IDO can regulate the immune system either through deprivation of tryptophan that is essential for T cell proliferation or via cytotoxic effects of kynurenine pathway metabolites on T cell survival. METHODS The sources of information used were obtained through Pubmed/Medline. RESULTS/CONCLUSION While IDO emerges as a regulator of immunity, its role in controlling allo-response is unfolding. IDO can control T cell responses to allo-antigens and induce generation of allo-specific regulatory T cells. Exploiting IDO as a modulator of transplant rejection, many groups have manipulated its activity to prolong allograft survival in transplantation models. Despite the initial promise, its application to clinical transplantation may be limited. We therefore examine the potentials and limitations associated with clinical translation of IDO into a therapeutic.
Collapse
Affiliation(s)
- Jianchao Quan
- Oxford University, John Radcliffe Hospital, Nuffield Department of Surgery, Headley Way, Oxford, OX3 9DU, UK
| | | | | | | |
Collapse
|
5
|
Lee JH, Ahn HH, Kim KS, Lee JY, Kim MS, Lee B, Khang G, Lee HB. Polyethyleneimine‐mediated gene delivery into rat pheochromocytoma PC‐12 cells. J Tissue Eng Regen Med 2008; 2:288-95. [DOI: 10.1002/term.94] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
6
|
Zhao X, Zhang Z, Pan F, Waigh TA, Lu JR. Plasmid DNA complexation with phosphorylcholine diblock copolymers and its effect on cell transfection. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:6881-6888. [PMID: 18500832 DOI: 10.1021/la800593q] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We examined a series of novel cationic MPC-based (2-methacryloyloxyethyl phosphorylcholine) copolymers as vectors for gene delivery, with emphasis on the assessment of the effects of the charge ratio (administered via pH variation) on the complex (polyplex) formation and the subsequent transfection efficiency. A combination of electrophoresis, dynamic light scattering, and small angle neutron scattering was used to characterize the structure and charge distribution of the polyplexes formed between the copolymer and the luciferase plasmid DNA. Polymers with larger hydrophobic side chains had lower p K a values and tended to aggregate more strongly. For a given copolymer, electrostatic interaction was the main driving force for the formation of the nanopolyplexes. When the cationic copolymers were in excess, the majority of the polyplexes formed was neutral, and only a small faction of them carried net positive charges. Polyplexes formed under excess copolymer protected the DNA from restriction enzyme digestion. As the copolymers were weak polyelectrolytes, the pH had a distinct effect on the structure and charge distribution of the polyplexes formed. Below the p K a, the copolymers were found to bind with the plasmid DNA in the form of unimers, while above the p K a, the copolymers self-aggregated and complexed with DNA in the form of micelles. It was subsequently found that unimer/DNA polyplexes were far more effective in the transfection of HEK293 cells than micellar DNA polyplexes. The results thus revealed that different hydrophobicities of the side chains in the copolymer series led to different nanostructuring and charge characteristics, which had a consequential effect on the transfection efficiency. This study provided useful insight into the molecular processes underlying polyplex formation and demonstrated a strong link between structural and physical properties of polyplexes and cell transfection efficiency.
Collapse
Affiliation(s)
- Xiubo Zhao
- Biological Physics Group, School of Physics and Astronomy, The University of Manchester, Schuster Building, Manchester M13 9PL, United Kingdom
| | | | | | | | | |
Collapse
|
7
|
Tan PH, Xue SA, Wei B, Holler A, Voss RH, George AJT. Changing viral tropism using immunoliposomes alters the stability of gene expression: implications for viral vector design. Mol Med 2007. [PMID: 17592557 DOI: 10.2119/2006-00052.tan] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many strategies for redirecting the tropism of murine Moloney leukemia virus (MMLV) have been described. Preformed virion-liposome complexes, termed virosomes, have been reported to be relatively stable. Virosomes mediate envelope-independent transduction that allows efficient superinfection of resistant cell lines; however, virosome-mediated transduction behaves in a non-target-specific manner. We developed a novel method using antibodies to direct MMLV to vascular endothelium. We have given the term immunovirosomes to the complexes formed between viruses, liposomes, and antibodies. These immunovirosomes improve the transduction efficiency of the viruses and alter their tropism. We have shown improved transduction when immunovirosomes were targeted at the endocytic receptors CD71 and CD62E/P and rather less good delivery when targeted at CD106. The enhancement of the transduction efficiency was transient, however, suggesting that rerouting the entry pathway of viruses alters the expression properties of the viruses.
Collapse
Affiliation(s)
- Peng H Tan
- Department of Immunology, Division of Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
| | | | | | | | | | | |
Collapse
|
8
|
Tan PH, Xue SA, Wei B, Holler A, Voss RH, George AJT. Changing viral tropism using immunoliposomes alters the stability of gene expression: implications for viral vector design. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2007; 13:216-26. [PMID: 17592557 PMCID: PMC1892767 DOI: 10.2119/2006–00052.tan] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 07/02/2006] [Accepted: 02/05/2007] [Indexed: 11/06/2022]
Abstract
Many strategies for redirecting the tropism of murine Moloney leukemia virus (MMLV) have been described. Preformed virion-liposome complexes, termed virosomes, have been reported to be relatively stable. Virosomes mediate envelope-independent transduction that allows efficient superinfection of resistant cell lines; however, virosome-mediated transduction behaves in a non-target-specific manner. We developed a novel method using antibodies to direct MMLV to vascular endothelium. We have given the term immunovirosomes to the complexes formed between viruses, liposomes, and antibodies. These immunovirosomes improve the transduction efficiency of the viruses and alter their tropism. We have shown improved transduction when immunovirosomes were targeted at the endocytic receptors CD71 and CD62E/P and rather less good delivery when targeted at CD106. The enhancement of the transduction efficiency was transient, however, suggesting that rerouting the entry pathway of viruses alters the expression properties of the viruses.
Collapse
Affiliation(s)
- Peng H Tan
- Department of Immunology, Division of Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK.
| | | | | | | | | | | |
Collapse
|
9
|
Theoharis S, Manunta M, Tan PH. Gene delivery to vascular endothelium using chemical vectors: implications for cardiovascular gene therapy. Expert Opin Biol Ther 2007; 7:627-43. [PMID: 17477801 DOI: 10.1517/14712598.7.5.627] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The vascular endothelium is an attractive target for gene therapy because of its accessibility and its importance in the pathophysiology of a wide range of cardiovascular conditions. In general, viral methods have been shown to be very effective at delivering genes to endothelium. The immunogenicity and pathogenicity associated with viral vectors have led increased efforts to seek alternative means of 'ferrying' therapeutic genes to endothelium or to decrease the short-comings of viral vectors. This paper reviews developments in non-viral technology. In addition, discussion also covers the mechanisms whereby existing chemical vectors deliver DNA to cells. Understanding the pathways of vector internalisation and intracellular traffic is important in developing strategies to improve vector technology. The authors propose that the chemical vector may represent a robust and versatile technology to 'ferry' therapeutic genes to vascular endothelium in order to modify the endothelial dysfunction associated with many cardiovascular diseases.
Collapse
Affiliation(s)
- Stefanos Theoharis
- Imperial College London, Department of Immunology, Division of Medicine, Hammersmith Hospital, Du Cane Road, London W12 ONN, UK
| | | | | |
Collapse
|
10
|
Tan PH, Tan PL, George AJT, Chan CLH. Gene therapy for transplantation with viral vectors – how much of the promise has been realised? Expert Opin Biol Ther 2006; 6:759-72. [PMID: 16856798 DOI: 10.1517/14712598.6.8.759] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Gene therapy holds promise in preventing the development of many diseases. One of the possible applications is the management of organ transplantation. Over the years, advances in vector development have allowed the clinical progression of this form of therapy to become more attainable. Viral vector technology has proved to be better than non-viral vectors at ferrying therapeutic genes to cells. However, many deficiencies in viral vectors hinder the full realisation of gene-based therapy in transplantation. Here, these deficiencies and their ramifications for the future of viral vector development are fully analysed. The authors propose that the slow progress of gene therapy in transplantation may be related to the deficiencies in viral vectors.
Collapse
Affiliation(s)
- Peng H Tan
- Oxford Transplant Centre, Oxford Radcliffe Hospitals NHS Trust, Oxford University, Churchill Hospital, Old Road, Oxford, OX3 7LJ, UK.
| | | | | | | |
Collapse
|
11
|
Beutelspacher SC, Tan PH, McClure MO, Larkin DFP, Lechler RI, George AJT. Expression of indoleamine 2,3-dioxygenase (IDO) by endothelial cells: implications for the control of alloresponses. Am J Transplant 2006; 6:1320-30. [PMID: 16686756 DOI: 10.1111/j.1600-6143.2006.01324.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Indoleamine 2,3-dioxygenase (IDO) is an important enzyme in the regulation of immune responses; cells that express IDO can suppress T-cell responses and promote tolerance. Because of the critical role of endothelial cells in graft rejection, we have investigated the role of IDO expression by vascular endothelial cells and its consequence on immunoregulation. We compared the expression of IDO by primary human umbilical vein endothelial cells (HUVECs), human saphenous vein endothelial cells (HSVECs) and arterially derived endothelial cells using reverse transcriptase PCR, Western blotting and assays for enzymatic activity. In HUVECs IDO is upregulated by incubation with cytokines or in mycoplasma-infected cells. On the other hand HSVECs and arterially derived endothelial cells express little IDO, which is poorly upregulated upon activation (except by mycoplasma). Inhibition of IDO activity improved the ability of HUVECs to stimulate allogeneic T-cell responses. If either HUVECs or HSVECs are transfected with the gene encoding IDO, then they are incapable of stimulating allogeneic T-cell responses and induce anergy in allospecific T cells (which can also act as regulatory cells). The variable expression of IDO in different endothelial cells is important not only in understanding the role of endothelial cells in the regulation of graft rejection, but also as a potential therapeutic strategy.
Collapse
Affiliation(s)
- S C Beutelspacher
- Department of Immunology, Division of Medicine, Faculty of Medicine, Imperial College London, Hammersmith Hospital, Du Cane Road, London, UK
| | | | | | | | | | | |
Collapse
|
12
|
Tan PH, Chan CLH, George AJT. Strategies to improve non-viral vectors – potential applications in clinical transplantation. Expert Opin Biol Ther 2006; 6:619-30. [PMID: 16706608 DOI: 10.1517/14712598.6.6.619] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Prevention of acute rejection has been well controlled with immunosuppressive drugs. However, the long-term control of rejection is less satisfactory and the side effects of chronic usage of these drugs are far from acceptable. Thus, more imaginative options for therapy need to be explored. Gene therapy has potential promise in preserving allografts, preventing rejection and inducing tolerance. Despite this initial promise in many animal models, the translation of gene therapy to the clinical arena has been slow. This may be related in part to the deficiencies in vector development. Existing viral vectors are efficient at transducing allografts, but they induce inflammatory and pathogenic effects. Although the alternative non-viral systems are relatively innocuous, they are less efficient at gene delivery. This review systematically analyses the limitations of non-viral vector technology and the strategies that have been developed to overcome these limitations. Future development of non-viral vectors may have potential application in clinical transplantation.
Collapse
Affiliation(s)
- P H Tan
- Department of Surgery, Oxford Radcliffe Hospitals NHS Trust, Horton Hospital, OX16 9AL, UK.
| | | | | |
Collapse
|