title: Calcium ions effectively enhance the effect of antisense peptide nucleic acids conjugated to cationic tat and oligoarginine peptides.
abstract: Cell-penetrating peptides have been widely used to improve cellular delivery of a variety of proteins and antisense agents. However, recent studies indicate that such cationic peptides are predominantly entering cells via an endosomal pathway. We now show that the nuclear antisense effect in HeLa cells of a variety of peptide nucleic acid (PNA) peptide conjugates is significantly enhanced by addition of 6 mM Ca(2+) (as well as by the lysosomotrophic agent chloroquine). In particular, the antisense activities of Tat(48-60) and heptaarginine-conjugated PNAs were increased 44-fold and 8.5-fold, respectively. Evidence is presented that the mechanism involves endosomal release. The present results show that Ca(2+) can be used as an effective enhancer for in vitro cellular delivery of cationic peptide-conjugated PNA oligomers, and also emphasize the significance of the endosomal escape route for such peptides.
authors.affiliation: Department of Medical Biochemistry and Genetics, The Panum Institute, University of Copenhagen, Blegdamsvej 3c, 2200 Copenhagen N., Denmark.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Shiraishi
authors.forename: Stanislava
authors.initials: S
authors.lastname: Pankratova
authors.forename: Peter E
authors.initials: PE
authors.lastname: Nielsen
mesh_terms: D000818:Animals; D001120:Arginine; D001692:Biological Transport; D002118:Calcium / Q000494:pharmacology*; D002451:Cell Compartmentation; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D005786:Gene Expression Regulation; D015696:Gene Products, tat / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D009842:Oligopeptides; D020135:Peptide Nucleic Acids / Q000737:chemistry / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D015696:Gene Products, tat; D016376:Oligonucleotides, Antisense; D009842:Oligopeptides; D020135:Peptide Nucleic Acids; D001120:Arginine; D002118:Calcium