Use of adeno-associated viral vector for delivery of small interfering RNA

Post-transcriptional gene silencing by small interfering RNAs (siRNAs) is rapidly becoming a powerful tool for genetic analysis of mammalian cells. Delivery of siRNA into mammalian cells is usually achieved via the transfection of double-stranded oligonucleotides or plasmids encoding RNA polymerase III promoter-driven small hairpin RNA. Recently, retroviral vectors have been used for siRNA delivery, which overcome the problem of poor transfection efficiency seen with the plasmid-based systems. However, retroviral vectors have several limitations, such as the need for active cell division for gene transduction, oncogenic potential, low titers and gene silencing. In this report, we have adapted a commercially available adenoassociated virus (AAV) vector for siRNA delivery into mammalian cells. We demonstrate the ability of this modified vector to deliver efficiently siRNA into HeLa S3 cells and downregulate p53 and caspase 8 expression. Our results suggest that AAV-based vectors are efficient vectors for the delivery of siRNA into mammalian cells. Based on the known ability of these vectors to infect both dividing and nondividing cells, their use as a therapeutic tool for the delivery of siRNA deserves further study.