Design of a novel highly efficient peptide-based siRNA-delivery vector, PepFect6

While small interfering RNAs (siRNAs) have been rapidly appreciated to induce gene silencing, efficient vectors for primary cells and for systemic in vivo delivery are lacking. We here present a novel chemically modified cell-penetrating peptide named PepFect6 (PF6) for efficient delivery of siRNAs into various types of cells including e.g. lymphocyte suspension cells and primary embryonic stem cells. Stable PF6/siRNA nano- particles rapidly enter entire cell populations resulting in strong and persistent RNAi responses, without associated transcriptomic or proteomic changes. In contrast to the majority of chemical reagents, PF6-mediated delivery is independent of cell confluence and, in most cases, not significantly hampered by the presence of serum. Finally, strong RNAi responses are observed in two different in vivo models following systemic delivery of PF6/siRNA in mice. Taken together, PF6 is an efficient siRNA delivery vector with superior delivery properties as compared to other tested transfection reagents. PepFec6 is a cell penetrating peptide (CPP). We have used it for bringing cargo into cells. In this study we compare PepFec6 to Lipofectamine 2000. In the actual experiments here, we have compared gene expression in HeLa cells treated with SiRNA corresponding to the gene HPRT1 with either Lipofectamine 2000 or PepFect6 as the carrier into the cells. For our submitted manuscript, we are using two M/A plots based on the microarray results to demonstrate the gene expression with cells treated with Lipo-SiRNA compared to untreated controls and PepFect-SiRNA compared to untreated cells.