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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2006-10-3
pubmed:abstractText
Low levels of gene delivery in vivo using replication-defective retroviral vectors have severely limited their application for clinical protocols. To overcome this problem, we describe here a semi-replication-competent retrovirus (s-RCR) in which the gag-pol and envelope (VSV-G, vesicular stomatitis virus G protein) genes were split into two vectors. This system offers potential advantages over both replication-defective vectors, in terms of efficiency of in vivo spread through a tumor, and all-in-one replication-competent vectors in terms of the payload of therapeutic genes that can be carried. We achieved a viral titer of s-RCR viruses approximately 70-fold higher than VSV-G pseudotyped, replication-defective vectors. In addition, s-RCR vectors induced tumor killing by the cytotoxicity of VSV-G during viral spread. Inclusion of the herpes simplex virus thymidine kinase (HSVtk30) gene into vectors significantly improved tumor killing activity followed by ganciclovir (GCV) treatment in vitro under conditions of low-level viral replication. However, at high levels of viral spread, VSV-G-mediated cytotoxicity predominated. Xenografts of human fibrosarcoma HT1080 cells, preinfected by semi-replicative green fluorescent protein vectors (semi-GFP), were completely non-tumorigenic in nude mice. Implantation of cells preinfected by semi-replicative TK30 vectors (semi-TK30) mixed with parental HT1080 cells at a ratio of 1:1 efficiently prevented tumor growth in mice treated by GCV. Direct intratumoral injection of HT1080 tumors growing in nude mice, or B16 murine melanoma in immunocompetent mice, with semi-TK30 viruses significantly prolonged survival. Injection of autologous cells (B16) producing semi-TK30 vector into B16 tumors prolonged survival only in mice treated with GCV but not with phosphate-buffered saline (PBS). In contrast, when xenogeneic cells (293T) producing semi-TK30 vectors were injected into B16 tumors, an optimal survival advantage was obtained in mice treated with PBS rather than GCV. These data indicate that complex interactions exist between direct cytotoxicity of VSV-G and HSVtk expression when placed in the context of additional immune parameters, which combine to determine the efficacy of the therapy. Taken together, our data suggest that s-RCR vectors have some potential advantages for development to deliver genes into tumors for cancer treatment but that a combination of factors will impact on the decision as to whether the s-RCR strategy is worth developing to full clinical trials.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0969-7128
pubmed:author
pubmed:issnType
Print
pubmed:volume
13
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1457-70
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed-meshheading:16724095-Animals, pubmed-meshheading:16724095-Antiviral Agents, pubmed-meshheading:16724095-Cell Line, pubmed-meshheading:16724095-Flow Cytometry, pubmed-meshheading:16724095-Ganciclovir, pubmed-meshheading:16724095-Gene Therapy, pubmed-meshheading:16724095-Genes, Transgenic, Suicide, pubmed-meshheading:16724095-Green Fluorescent Proteins, pubmed-meshheading:16724095-Humans, pubmed-meshheading:16724095-Leukemia Virus, Murine, pubmed-meshheading:16724095-Melanoma, Experimental, pubmed-meshheading:16724095-Membrane Glycoproteins, pubmed-meshheading:16724095-Mice, pubmed-meshheading:16724095-Mice, Nude, pubmed-meshheading:16724095-Neoplasms, pubmed-meshheading:16724095-Neoplasms, Experimental, pubmed-meshheading:16724095-Oncolytic Virotherapy, pubmed-meshheading:16724095-Simplexvirus, pubmed-meshheading:16724095-Thymidine Kinase, pubmed-meshheading:16724095-Transduction, Genetic, pubmed-meshheading:16724095-Viral Envelope Proteins, pubmed-meshheading:16724095-Virus Replication
pubmed:year
2006
pubmed:articleTitle
VSV-G pseudotyped, MuLV-based, semi-replication-competent retrovirus for cancer treatment.
pubmed:affiliation
Molecular Medicine Program, Mayo Clinic, Rochester, MN 55902, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural