Use of lentiviral vectors for delivery of small interfering RNA

Silencing of gene expression by small interfering RNAs (siRNAs) is rapidly becoming a powerful tool for genetic analysis of mammalian cells. Although in the original studies expression of siRNA in mammalian cells was achieved via the transfection of double stranded oligonucleotides, subsequent studies described the use of plasmids to achieve long-term and stable expression of siRNA. Recently, several groups have described the use of retroviral vectors for siRNA delivery. However, retroviral vectors require active cell division for gene transfer and also suffer from the problem of gene-silencing. In this report we have modified a commercially available self-inactivating lentiviral vector for the delivery of siRNA into mammalian cells. We demonstrate the ability of this modified vector to efficiently transfer siRNA into HeLa S3 cells and downregulate p53 expression. Our results suggest that lentiviruses are efficient vectors for delivery of siRNA into mammalian cells. Based on the known ability of these vectors to infect both dividing and non-dividing cells and achieve long-term multilineage gene expression, their use as a therapeutic tool for the delivery of siRNA deserves further study.