Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Viral vector”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources
PubMed2004

Endocrine aspects of cancer gene therapy.

The field of cancer gene therapy is in continuous expansion, and technology is quickly moving ahead as far as gene targeting and regulation of gene expression are concerned. This review focuses on the endocrine aspects of gene therapy, including the possibility to exploit hormone and hormone receptor functions for regulating therapeutic gene expression, the use of endocrine-specific genes as new therapeutic tools, the effects of viral vector delivery and transgene expression on the endocrine system, and the endocrine response to viral vector delivery. Present ethical concerns of gene therapy and the risk of germ cell transduction are also discussed, along with potential lines of innovation to improve cell and gene targeting.

Clinical Trials as Topic↗
PubMed1995

Gene transfer of wild-type p53 results in restoration of tumor-suppressor function in a medulloblastoma cell line.

The replacement of functional genes into cells that lack genes or have mutant genes is the basis of gene therapy. In cancer, where cells often have multiple genetic defects, the replacement of critical genes may suffice to suppress cell growth or induce cell death. The high frequency of mutations of the p53 tumor-suppressor gene in human cancers, including primary brain tumors, suggests that p53 plays a critical role in carcinogenesis and tumor progression. We report the successful transfer of the wild-type p53 gene using a defective herpes simplex viral vector into a human medulloblastoma cell line containing a mutant copy of p53. Upon gene transfer, we detected novel expression of wild-type p53 protein in the cells. In addition, the p53 protein was functionally active, since gene transfer resulted in increased levels of mdm2 proteins and induced cell cycle arrest of the majority of transduced cells. To our knowledge, this is the first report of the use of this vector system to carry wild-type p53. We conclude that defective herpes simplex viral vectors can transfer and express p53 in human primary brain tumor cells in vitro, restoring wild-type p53 tumor-suppressor functions.

Animals↗
PubMed2003

Prediction of size distribution of lipid-peptide-DNA vector particles using Monte Carlo simulation techniques.

Concerns with insertional mutagenesis for retrovirus and immunogenicity for adenovirus have motivated research into development of non-viral vectors that can safely deliver desired gene constructs to target cells in tissues and organs. Many non-viral vectors suffer from unacceptably poor in vivo cell transfection and low transgene expression. Evidence suggests that cell transfection is linked to particle size - vector particles below about 200 nm are considered desirable. Experimental measurements indicate, however, that vector particles are susceptible to significant aggregation under most conditions of pH and ionic strength, including physiological conditions, although there are currently no means of predicting the kinetics of aggregation. The present paper addresses this challenge by presenting a mathematical framework based on the Monte Carlo simulation techniques for modelling the dynamics of aggregation. The approach is used to simulate the evolution of particle-size distribution for an integrin-targeting lipid-peptide-DNA vector system in buffers of different pH and ionic strength. The simulations required two input parameters, including the initial-size distribution of the particles and a fitting parameter (alpha). Comparison of simulations with experimental data showed that alpha was closely related to the zeta potential of the particles in the buffer medium, making simulations fully predictive. The modelling approach may be used in other vector systems.

DNA↗
PubMed2005

Specific targets in tumor tissue for the delivery of therapeutic genes.

Gene therapy is part of a growing field in molecular medicine, which will gain importance in the treatment of human diseases. Until now, almost two thirds of all clinical trials performed in gene therapy are directed against Cancer As solid tumors exceeding a certain size rely on blood supply, the administration of particulate gene delivery vectors via the bloodstream is a promising concept. Tumor cells and the tumor vasculature both offer specific molecular targets, which can be utilized for the site directed delivery of therapeutic genes. Passive targeting of macromolecular drugs including gene delivery vectors to tumors can be achieved by the so called enhanced permeability and retention (EPR) effect. The specificity can be markedly enhanced when tumor targeting ligands are used. Viral vectors, which usually do not have a natural tropism for tumor tissue, were generated to carry tumor targeting molecules on their surface. Synthetic gene delivery vectors, based on cationic lipids or cationic polymers were biochemically modified to incorporate ligands specific for tumor cells or tumor vasculature. For systemic application, these delivery systems have to fulfill certain conditions. The delivery vector should not induce any immunogenic and inflammatory responses. Several studies were conducted to reduce the immunogenicity of viral vectors; surface modification of non-viral gene delivery systems reduced their non-specific interaction with blood components. On the genetic level, tumor specific promoters add additional layers of specificity restricting the transgene expression to the tumor tissue. This review will cover the systemic application of particulate gene transfer vectors targeted to tumors and will give an overview of therapeutic concepts for cancer gene therapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

A novel method for viral gene delivery in solid tumors.

Intratumoral infusion is the most commonly used method for viral gene delivery in clinical trials for cancer treatment. However, a potential problem in this approach is that viral vectors may disseminate from tumor to normal tissues during and after the infusion. To reduce the dissemination, we developed a novel method based on a biocompatible polymer, poloxamer 407, which could significantly increase the viscosity of virus suspension when the temperature was changed from 4 degrees C to 37 degrees C. With this method, we could significantly increase transgene expression in solid tumors and reduce virus dissemination by 2 orders of magnitude after intratumoral infusion of adenoviral vectors. The mechanism of reduction was likely to be that the viscous poloxamer solution blocked convection of viral vectors in the interstitial space and the lumen of microvessels in the vicinity of the infusion site. This method has a potential to be used in the clinic for enhancing efficacy and reducing toxicity in viral gene therapy.

Adenoviridae↗
PubMed2004

Recent advances in the pharmacology of neurological gene therapy.

The choice of vectors, transgenes, regulatory elements, delivery approaches and the capacity to transduce the appropriate target cell type all influence the effectiveness of gene therapy for neurological diseases. Furthermore, even if many strategies are sound and effective in experimental animals, issues relating to side effects of gene therapy, longevity of therapeutic transgene expression and diffusion throughout the brain can limit the clinical potential of gene therapy. During the past 12-18 months, there have been significant advances in the following areas: the capacity to target vectors to predetermined cells types; the development of gene therapy approaches for the treatment of dominant inherited and neurodegenerative diseases; the capacity to achieve systemic delivery of viral vectors to the brain; and the development of viral vectors to model neurological diseases.

Animals↗
PubMed1994

The new frontier: gene and oligonucleotide therapy.

Gene and oligonucleotide therapy are emerging as clinically viable therapeutic regimens for genetic, neoplastic, and infectious diseases. Approaches include insertion of human genes in viral vectors including recombinant retrovirus, adenovirus, adeno-associated virus, and herpes simplex virus-1, or recombinant bacterial plasmids. Viral vectors transfect cells directly; plasmid DNA is delivered with the help of cationic liposomes (lipofection), polylysine conjugates, gramicidin S, artificial viral envelopes or other such intracellular carriers. Major areas of interest include replacement of the cystic fibrosis transmembrane regulator gene and the alpha 1-antitrypsin gene; arrest of human immunodeficiency virus infection; and reversal of tumorigenicity and cancer immunization, among others. Oligonucleotide therapy is principally focusing on the same areas, although the approach is to halt DNA transcription or messenger RNA translation with code-blocking triple-helix-forming or "antisense" oligomers. Contributions from the pharmaceutical sciences are expected in pharmaceutical chemistry, drug delivery systems design, analytical chemistry, and biopharmaceutics.

Animals↗
PubMed2001

Novel baculovirus expression vectors that provide sialylation of recombinant glycoproteins in lepidopteran insect cells.

This report describes novel baculovirus vectors designed to express mammalian beta1,4-galactosyltransferase and alpha2,6-sialyltransferase genes at early times after infection. Sf9 cells infected with these viral vectors, unlike cells infected with a wild-type baculovirus, produced a sialylated viral glycoprotein during the late phase of infection. Thus, the two mammalian glycosyltransferases encoded by these viral vectors are necessary and sufficient for sialylation of a foreign glycoprotein in insect cells under the conditions used in this study. While some of the new baculovirus vectors described in this study produced less, one produced wild-type levels of infectious budded virus progeny.

Animals↗
PubMedDate not supplied

Non-viral, integrin-mediated gene transfer into fibroblasts from patients with lysosomal storage diseases.

BACKGROUND: Non-viral vectors consisting of Lipofectin/integrin-targeting peptide/DNA (LID) complexes have great potential for gene therapy, as they are safe, simple, and able to package large DNA molecules. In this study, these vectors were evaluated in vitro for the therapy of lysosomal storage disorders. METHODS: Non-viral vectors were designed to deliver therapeutic genes by integrin-mediated uptake into fibroblasts from patients with the lysosomal storage disorders fucosidosis and Fabry disease, which result from deficiencies of alpha-L-fucosidase and alpha-galactosidase A, respectively. The vectors consisted of a complex (LID) of Lipofectin and a peptide containing an integrin-targeting domain and a poly-lysine domain to which was bound plasmid DNA, containing alpha-L-fucosidase (LID-alpha-Fuc) or alpha-galactosidase A (LID-alpha-Gal). RESULTS: Patients' fibroblasts transfected with LID-alpha-Fuc and LID-alpha-Gal produced the corresponding enzyme at levels which were 10-40% of the total activity in cultures of normal fibroblasts. However, 95-98% of this activity was secreted. Transfection of endothelial cells, the main target cells in Fabry disease, with an LID-alpha-Gal produced a total alpha-galactosidase activity 65% higher than that in untransfected cultures after 6 days, 67% of the activity being secreted. Although transfection of fibroblasts with LID complexes also caused small changes in the distribution of endogenous lysosomal enzymes, it did not appear to affect the viability of the cells. CONCLUSIONS: The integrin-mediated transfer of genes encoding lysosomal enzymes into cells results in the secretion of large amounts of normal enzyme that could be taken up by other cells. This could be a useful strategy for enzyme-replacement therapy.

Cell Line↗
PubMed2004

Modular protein engineering for non-viral gene therapy.

Despite the recognized potential of viral vectors for gene therapy, growing biological concerns are prompting the exploration of safer, non-viral vectors to deliver therapeutic nucleic acids. In this context, recombinant proteins can be bioproduced on a large scale, without the need for further in vitro modifications, being free of known or suspected biohazards. For these vehicles to act as efficient gene-delivery devices, they must perform relevant functions that mimic those of viruses; namely, nucleic acid condensation, targeted cell attachment and internalization, endosomal escape and nuclear transfer. Modular engineering enables the construction of chimeric polypeptides in which selected domains, potentially from different origins, provide the required activities. An equilibrate combination and spatial distribution of such partner elements has generated promising prototypes, able to deliver expressible DNA to tissue culture but also to specific cell-types in whole organisms.

Animals↗
PubMed2004

Gene-based vaccines and immunotherapeutics.

DNA vaccines, comprised of plasmid DNA encoding proteins from pathogens, allergens, and tumors, are being evaluated as prophylactic vaccines and therapeutic treatments for infectious diseases, allergies, and cancer; plasmids encoding normal human proteins are likewise being tested as vaccines and treatments for autoimmune diseases. Examples of in vivo prophylaxis and immunotherapy, based on different types of immune responses (humoral and cellular), in a variety of disease models and under evaluation in early phase human clinical trials are presented. Viral vectors continue to show better levels of expression than those achieved by DNA plasmid vectors. We have focused our clinical efforts, at this time, on the use of recombinant viral vectors for both vaccine as well as cytokine gene transfer studies. We currently have four clinical programs in cancer immunotherapy. Two nonspecific immunotherapy programs are underway that apply adenoviral vectors for the transfer of cytokine genes into tumors in situ. An adenovirus-IFN gamma construct (TG1042) is currently being tested in phase II clinical trials in cutaneous lymphoma. A similar construct, adenovirus-IL2 (TG1024), also injected directly into solid tumors, is currently being tested in patients with solid tumors (about one-half of which are melanoma). Encouraging results are seen in both programs. Two cancer vaccine immunotherapy programs focus on two cancer-associated antigens: human papilloma virus E6 and E7 proteins and the epithelial cancer-associated antigen MUC1. Both are encoded by a highly attenuated vaccinia virus vector [modified vaccinia Ankara (MVA)] and both are coexpressed with IL-2. Encouraging results seen in both of these programs are described.

Antigens, Neoplasm↗
PubMed1999

Development of human papillomavirus plasmids capable of episomal replication in human cell lines.

Gene delivery into human cells has been facilitated by the development of viral vector systems. These vectors have shown great potential for the efficient delivery of therapeutic genes into human cells. A problem with many of the existing systems, however, is the integration of these vectors into the chromosome which affects the length of gene expression and may promote oncogenic transformation. In an effort to develop viral vectors that can replicate extrachromosomally in human cells, we have generated human papillomavirus (HPV) plasmids containing all the elements required for replication on a single DNA molecule. HPV plasmids containing the viral E1 and E2 genes (or the E1 gene alone) and an origin of replication were shown to replicate to significant levels in the transfected human cervical carcinoma C-33A cell line. Since approaches towards the possible gene therapy of cystic fibrosis (CF) are currently under intensive investigation, we have also tested short-term replication of HPV plasmids in the IB3 cell line derived from a CF patient. Our results demonstrate that HPV plasmids are capable of extrachromosomal replication in these cell lines and may potentially be important vectors for the delivery of therapeutic genes into human cells.

Cystic Fibrosis↗
PubMed1997

Retroviral mediated gene transfer of the Fanconi anemia complementation group C gene to hematopoietic progenitors of group C patients.

Fanconi Anemia (FA) is a rare genetic disorder characterized by progress pancytopenia, congenial abnormalities, and a predisposition to malignancy. Therapy is currently limited to allogeneic marrow transplantation; patients lacking a suitable donor usually die from aplasia or acute leukemia. Recently, mutation in a novel gene named FACC (Fanconi anemia C-complementing) has been identified as causing one type of FA. FACC mutations, which introduce splicing errors or stop codons, have been identified in approximately 15% of FA patients. We have recently been successful in functional complementation of four FA cell lines using retroviral vectors to transfer a copy of the normal FACC gene. We also analyzed the ability of our viral vectors to functionally correct hematopoietic progenitor cells from a patient bearing a splice donor mutation. As for the lymphoid cell lines, these CD34-enriched cells were extremely sensitive to MMC. After infection of these progenitor cells with viral vectors bearing normal FACC, the progenitors gave rise to increased numbers of colonies both in the absence and presence of up to 5nM MMC, whereas control cells were completely destroyed by 1nM MMC. In summary, we have demonstrated that: (1) retroviral vectors can be engineered to transfer a normal FACC gene to FA(C) lymphoid cell lines and primary hematopoietic cells; (2) introduction of a normal FACC gene into CD34+ progenitors markedly enhances their growth in the absence and presence of MMC. This study is designed to determine whether hematopoietic progenitors transduced with the normal FACC gene can be reinfused safely into FA(C) patients. CD34+ cells obtained from G-CSF mobilized peripheral blood will be transduced ex vivo over a 72-hour period in the presence of IL-3, IL-6, and Stem Cell Factor with the FACC retroviral vector. These transduced cells will be reinfused into FA(C) patients. Patients will be monitored for toxicities as well as evidence of successful gene transfer and expression. The procedure will be repeated up to a total of 4 times with each treatment 2-4 months apart. Theoretically, these rescued stem cells should have a selective growth advantage within the hypoplastic FA marrow environment in vivo.

Cell Cycle Proteins↗
PubMed2005

Targeting viral-mediated transduction to the lung airway epithelium with the anti-inflammatory cationic lipid dexamethasone-spermine.

We formulated adenovirus (AdV) vectors with cationic steroid liposomes containing dexamethasone-spermine (DS)/dioleoylphosphatidylethanolamine (DOPE) in an effort to overcome the lack of apically expressed AdV vector receptors on airway epithelial cells and to reduce the inflammation associated with AdV vector exposure. An AdV vector (1 to 2.5 x 10(11) genome copies) expressing human placental alkaline phosphatase or beta-galactosidase (LacZ) was delivered alone or complexed with DS/DOPE, DC-Chol/DOPE, or dexamethasone to C57Bl/6 mice via intranasal instillation. Formulation of the AdV vector with DS/DOPE and DC-Chol/DOPE resulted in transgene expression targeted only to the airway epithelial cells with minimal expression in alveolar cells, while AdV alone caused high alveolar transduction. The DS/DOPE and dexamethasone formulations greatly reduced cellular infiltrates compared to AdV vector alone, while formulation with DC-Chol/DOPE did not. IFN-gamma was significantly elevated at day 7 in mice receiving only the AdV vector compared to the AdV vector formulated with DS/DOPE, DC-Chol/DOPE, or dexamethasone. Lipid formulation of adeno-associated virus vector expressing LacZ also produced airway epithelial targeting, similar to the AdV vector. Viral vectors can be formulated with DS/DOPE to improve targeting to the airway epithelium in vivo and to attenuate vector-induced inflammation through the pharmacological activity of DS.

Alkaline Phosphatase↗
PubMed2006

A method to estimate the efficiency of gene expression from an integrated retroviral vector.

BACKGROUND: Proviral gene expression is a critical step in the retroviral life cycle and an important determinant in the efficiency of retrovirus based gene therapy vectors. There is as yet no method described that can assess the efficiency of proviral gene expression while vigorously excluding the contribution from unstable species such as passively transferred plasmid and LTR circles. Here, we present a method that can achieve this. RESULTS: Proviral gene expression was detected by the activity of the puromycin resistance gene encoded in the viral vector, and quantified by comparing the growth curve of the sample under puromycin selection to that of a series of calibration cultures. Reproducible estimates of the efficiency of proviral gene expression could be derived. We confirm that contamination from unstable species such as passively transferred plasmid used in viral vector production and unintegrated viral DNA can seriously confound estimates of the efficiency of transduction. This can be overcome using a PCR based on limiting dilution analysis. CONCLUSION: A simple, low cost method was developed that should be useful in studying the biology of retroviruses and for the development of expression systems for retrovirus based gene therapy.

Animals↗
PubMed1999

The nucleocapsid domain is responsible for the ability of spleen necrosis virus (SNV) Gag polyprotein to package both SNV and murine leukemia virus RNA.

Murine leukemia virus (MLV)-based vector RNA can be packaged and propagated by the proteins of spleen necrosis virus (SNV). We recently demonstrated that MLV proteins cannot support the replication of an SNV-based vector; RNA analysis revealed that MLV proteins cannot efficiently package SNV-based vector RNA. The domain in Gag responsible for the specificity of RNA packaging was identified using chimeric gag-pol expression constructs. A competitive packaging system was established by generating a cell line that expresses one viral vector RNA containing the MLV packaging signal (Psi) and another viral vector RNA containing the SNV packaging signal (E). The chimeric gag-pol expression constructs were introduced into the cells, and vector titers as well as the efficiency of RNA packaging were examined. Our data confirm that Gag is solely responsible for the selection of viral RNAs. Furthermore, the nucleocapsid (NC) domain in the SNV Gag is responsible for its ability to interact with both SNV E and MLV Psi. Replacement of the SNV NC with the MLV NC generated a chimeric Gag that could not package SNV RNA but retained its ability to package MLV RNA. A construct expressing SNV gag-MLV pol supported the replication of both MLV and SNV vectors, indicating that the gag and pol gene products from two different viruses can functionally cooperate to perform one cycle of retroviral replication. Viral titer data indicated that SNV cis-acting elements are not ideal substrates for MLV pol gene products since infectious viruses were generated at a lower efficiency. These results indicate that the nonreciprocal recognition between SNV and MLV extends beyond the Gag-RNA interaction and also includes interactions between Pol and other cis-acting elements.

Amino Acid Sequence↗
PubMed2002

Advances in the development of non-human viral DNA-vectors for gene delivery.

Within the last two decades, various vectors based on human viruses have been developed as gene transfer vehicles for gene therapy applications and vaccination. However, one yet unresolved problem connected to the use of viral vectors in humans is the pre-existing immunity to most of these vectors in the vast majority of the population which can result in impaired gene transfer efficiency and increased secondary toxicity. One approach to solve this problem is the development of recombinant viruses of non-human origin as vectors for gene transfer. The major rationale for using such vectors is the avoidance of vector neutralization by pre-existing antibodies directed against the virus on which the vector is based. Use of vectors based on non-human viruses may therefore allow the use of lower initial vector doses to achieve efficient gene transfer. Side-effects caused by interactions between vectors derived from human viruses with a primed immune system or with blood components could also be reduced. Furthermore, these vectors might show new cell type tropisms and could therefore infect tissue and organs that are not accessible to current viral vectors. This review outlines some of the problems inherent in the human origin of current viral vectors and describes features and progress with non-human adenovirus and baculovirus-derived vectors that may provide alternatives.

Adenoviridae↗
PubMed2005

Elicitation of neutralizing antibodies by intranasal administration of recombinant vesicular stomatitis virus expressing human immunodeficiency virus type 1 gp120.

Recombinant viral vectors are useful tools for AIDS vaccine development. However, expression of HIV-1 envelope genes using viral vectors has not been successful in the induction of potent neutralizing antibodies in vivo. We took advantage of the strong immunogenicity of vesicular stomatitis virus (VSV)-based vector and expressed HIV-1 HXB2 gp120 gene in the recombinant VSV. Our results showed that HIV-1 gp120 protein expressed by the recombinant VSV retained the native conformation of the protein to some degree and was recognized by two well-characterized broad anti-HIV-1 neutralizing monoclonal antibodies b12, 2G12. We further showed that only one time intranasal immunization with the recombinant VSV led to production of anti-HIV-1 anti-sera in mice. In addition, we found that the anti-sera had the ability to neutralize not only HXB2 envelope-pseudotyped HIV-1 viruses but also HIV-1 pseudotyped viruses with JRFL envelopes. These results suggest that HIV-1 gp120 expressed by the recombinant VSV, in combination with the route of intranasal administration, is an effective strategy to evaluate the immunogenicity of HIV-1 envelope protein and its variants in mice.

Administration, Intranasal↗