Peptide-assisted delivery of steric-blocking antisense oligomers.

TitlePeptide-assisted delivery of steric-blocking antisense oligomers.
Publication TypeJournal Article
Year of Publication2003
AuthorsMoulton HM, Moulton JD
JournalCurrent opinion in molecular therapeutics
Date Published2003 Apr
KeywordsCarrier Proteins, Down-Regulation, Drug Delivery Systems, Forecasting, Gene Products, tat, Molecular Probes, Oligonucleotide Array Sequence Analysis, Oligonucleotides, Antisense, Peptides, Up-Regulation

Cationic transport peptides conjugated to steric blocking antisense oligomers (oligos) increase oligo uptake in eukaryotic cell lines, bacteria and mice. Recent reports of arginine-rich transport peptide conjugates strongly suggest that the mechanism of uptake is primarily endocytotic and that previous assay techniques produced confounding artifacts that led to the old non-endocytotic, membrane-penetrating peptide model. The artifacts result from fixing cells for fluorescent microscopy and from using non-trypsinized cells for flow cytometry. Fixing cells redistributes the peptide or peptide-oligo conjugates associated with the outside of cell membranes and trapped in endosomes, giving apparent diffuse cytosolic and nuclear fluorescence. Cationic peptides bound to the outer surface of cells, if not removed, skew fluorescence data obtained by flow cytometry, leading to the earlier conclusions. Upregulation assays now provide a tool for comparing the efficacy of conjugates, measuring oligo uptake by quantitating antisense activity of conjugates. These assays, developed in cell culture and mouse models, are faster and have higher signal-to-noise ratios than downregulation assays. Thus, a convenient and effective method now exists to screen transport peptides.

Alternate JournalCurr. Opin. Mol. Ther.