title: Adenovirus encoding HIV-1 Vpr activates caspase 9 and induces apoptotic cell death in both p53 positive and negative human tumor cell lines.
abstract: The targeted delivery of genes whose products arrest the cell cycle and/or induce apoptosis represent an important tool for the understanding and controlling forms of unregulated cell growth. The vpr gene product of HIV-1 has been reported to interfere with cell growth and induce apoptosis, but the mechanism of its action is not clearly understood. In order to study these important properties of Vpr, we created a recombinant adenovirus H5.010CMV-vpr (adCMV-vpr) as a tool to deliver the vpr gene to various cell lines to examine its biology. Vpr protein expression was confirmed by Western blot analysis in adCMV-vpr infected cells. We tested the effects of adCMV-vpr on cell growth of several tumor cell lines. Infection of both p53 positive and p53 deficient tumor cell lines with adCMV-vpr resulted in dramatic induction of cell death in short-term assays. We observed that apoptosis was induced through the mitochondrial pathway as we observed changes in the cytochrome c content accompanied by caspase 9 activation. As Bcl-2 is reported to interfere with apoptosis through the mitochondrial pathway, we examined the effect of adCMV-vpr in Bcl-2 over expressing cell lines. We observed that Bcl-2 overexpression does not inhibit adCMV-vpr induced apoptosis. The properties of adCMV-vpr inducing apoptosis through caspase 9 in a p53 pathway independent manner suggest that this is an important reagent. Such a vector may give insight into approaches designed to limit the growth of pathogenic human cells.
authors.affiliation: Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA 19104, USA.
authors.forename: Karuppiah
authors.initials: K
authors.lastname: Muthumani
authors.forename: Donghui
authors.initials: D
authors.lastname: Zhang
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Hwang
authors.forename: Sagar
authors.initials: S
authors.lastname: Kudchodkar
authors.forename: Nathanael S
authors.initials: NS
authors.lastname: Dayes
authors.forename: Brijal M
authors.initials: BM
authors.lastname: Desai
authors.forename: Afshan S
authors.initials: AS
authors.lastname: Malik
authors.forename: Joo-Sung
authors.initials: JS
authors.lastname: Yang
authors.forename: Michael A
authors.initials: MA
authors.lastname: Chattergoon
authors.forename: Henry C
authors.initials: HC
authors.lastname: Maguire
authors.forename: David B
authors.initials: DB
authors.lastname: Weiner
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D002453:Cell Cycle; D048429:Cell Size; D002470:Cell Survival; D004789:Enzyme Activation; D005434:Flow Cytometry; D017353:Gene Deletion; D015870:Gene Expression; D016336:Gene Products, vpr / Q000235:genetics / Q000378:metabolism*; D005822:Genetic Vectors / Q000235:genetics; D006367:HeLa Cells; D006801:Humans; D016133:Polymerase Chain Reaction; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014161:Transduction, Genetic; D019076:Transgenes / Q000235:genetics; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D016336:Gene Products, vpr; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; C506433:CASP9 protein, human; D053453:Caspase 9; D020169:Caspases