RESUMO
BACKGROUND: Artificial virus-like particles (AVPs) represent a novel type of liposomal vector resembling retroviral envelopes. AVPs are serum-resistant and non-toxic and can be endowed with a peptide ligand as a targeting device. The vitronectin receptor, alphavbeta3-integrin, is commonly upregulated on malignant melanoma cells. In the present study we investigated whether AVPs carrying cyclic peptides with an RGD integrin binding motif (RGD-AVPs) are suitable for the specific and efficient transduction of human melanoma cells. METHODS: Plasmid DNA was complexed with low molecular weight non-linear polyethyleneimine and packaged into anionic liposomes. Transduction efficiencies were determined after transient transfection of different cell lines in serum-free medium using green fluorescent protein or luciferase reporter genes. RESULTS: We demonstrated that RGD-AVPs transduced human melanoma cells with high efficiencies of > 60%. Efficient transduction was clearly dependent on the presence of the cyclic RGD ligand and was selective for melanoma cells. The specificity of the vector system could be further enhanced by using the melanocyte-specific tyrosinase promoter to drive transgene expression. CONCLUSION: Our findings suggest that the AVP technology is a useful approach for generating highly efficient and specific non-viral vectors for melanoma targeting, in particular in a setting of combined transductional and transcriptional targeting.
Assuntos
Terapia Genética/métodos , Receptores de Vitronectina/genética , Transcrição Gênica , Transdução Genética , Vírus , Sequência de Aminoácidos , Humanos , Lipossomos , Melanoma , Dados de Sequência Molecular , Peptídeos/síntese química , Peptídeos/química , Plasmídeos , Receptores de Vitronectina/uso terapêutico , Proteínas Recombinantes de Fusão/análise , Proteínas Recombinantes de Fusão/genética , Transfecção/métodos , Células Tumorais CultivadasRESUMO
Targeting the tumor vasculature by gene therapy is a potentially powerful approach, but suitable vectors have not yet been described. We have designed a new type of liposomal vector, based on the composition of anionic retroviral envelopes, that is serum-resistant and nontoxic. These artificial virus-like envelopes (AVEs) were endowed with a cyclic RGD-containing peptide as a targeting device for the a(v)beta3-integrin on tumor endothelial cells (ECs). The packaging of plasmid DNA complexed with low-molecular-weight, nonlinear polyethyleneimine into these AVEs yielded artificial virus-like particles (AVPs) that transduced ECs with efficiencies of up to 99%. In contrast, transduction of a variety of other cell types by these RGD-AVPs was comparably inefficient under the same experimental conditions. This EC selectivity was mediated, in part, but not exclusively, by the RGD ligand, as suggested by the reduced, but still relatively high, transduction efficiency seen with AVPs lacking RGD. The interaction of anionic lipids of the AVPs with ECs may therefore contribute to the observed selective and highly efficient transduction of this cell type. These findings suggest that the targeted AVE technology is a useful approach to create highly efficient nonviral vectors.
