Combined antitumor effect of Ad-bFGF-siRNA and Ad-Vpr on the growth of xenograft glioma in nude mouse model.
ABSTRACT Basic fibroblast growth factor (bFGF) has been demonstrated to correlate with glioma grade and clinical outcome and has established its possible usefulness as a target for glioma therapy. Vpr has been described as an antitumor agent and displays a potent antitumor nature. Here, we try to investigate whether a combined treatment with bFGF-siRNA and Vpr gene would have a enhanced effectiveness on glioma in vitro and in vivo.After treatments with only Ad-bFGF-siRNA, only Ad-Vpr, and a combination of both, we assessed the changes in cell proliferation, cell cycle, and apoptosis in vitro by the methods of MTT, PI and FITC-AnnexinV double staining, respectively. In addition, we also evaluated the combined effect of bFGF-siRNA and Vpr gene therapy on glioma in vivo using xenograft glioma models in nude mice. Combined Ad-bFGF-siRNA and Ad-Vpr treatment was more better successful in inhibiting cell proliferation in comparison with treatments of either Ad-bFGF-siRNA or Ad-Vpr alone. Treatment of Ad-Vpr alone or a treatment of a combination of Ad-bFGF-siRNA and Ad-Vpr induced the G2/M cell cycle arrest and apoptosis; however, combined treatment was more effective than the Ad-Vpr treatment alone. Although each single treatment can slow the growth of xenograft glioma, the combined treatment with Ad-bFGF-siRNA and Ad-Vpr was better than either the Ad-bFGF-siRNA or Ad-Vpr treatment alone. Our results suggest that the combination therapy with bFGF-siRNA and Vpr gene can achieve a enhanced activity of anti-glioma, supporting the idea that the combination of these two antitumor agents could open new perspectives in glioma therapy.
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ABSTRACT: RNA interference (RNAi) is now an umbrella term referring to post-transcriptional gene silencing mediated by either degradation or translation arrest of target RNA. This process is initiated by double-stranded RNA with sequence homology driving specificity. The discovery that 21-23 nucleotide RNA duplexes (small-interfering RNAs, siRNAs) mediate RNAi in mammalian cells opened the door to the therapeutic use of siRNAs. While much work remains to optimize delivery and maintain specificity, the therapeutic advantages of siRNAs for treatment of viral infection, dominant disorders, cancer, and neurological disorders show great promise.Gene Therapy 02/2005; 12(1):5-11. · 4.32 Impact Factor
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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.Oncogene 08/2002; 21(30):4613-25. · 7.36 Impact Factor
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ABSTRACT: Viral protein R (Vpr) is a 14kD, 96 amino acid accessory protein of the HIV virion that has been demonstrated to have important functions in the viral replication cycle including, among others, the induction of cell cycle arrest and apoptosis in rapidly proliferating cells, which results in immune dysfunction in infected individuals. Several investigators have studied the potential use of the apoptosis inducing and cell cycle arrest effect of Vpr as an anti-tumor therapeutic. In vitro studies have indicated that Vpr is cytotoxic against a large number of different tumor cell types including a number that are p53 independent. Likewise, some in vivo tumor studies using different delivery platforms/methods have indicated an anti-cancer effect mediated by Vpr. Our group has used the aggressive and poorly immunogenic murine melanoma tumor line B16.F10 as a model to deliver, through in vivo electroporation, Vpr expressing plasmids to established tumors and have demonstrated that this treatment regimen can induce growth attenuation and tumor regression in a proportion of the treated mice and appears to be associated with the induction of intratumoral apoptosis. Overall, to date, the data from a number of research groups, including our own, have indicated that Vpr has biological activity against a number of tumors in both in vivo and in vitro models and, as such, may be a potential candidate for testing in human clinical trials. In this report, we summarize the evidence supporting this hypothesis.Current HIV research 04/2009; 7(2):144-52. · 1.98 Impact Factor