title: Cellular Antisense Activity of PNA-Oligo(bicycloguanidinium) Conjugates Forming Self-Assembled Nanoaggregates.
abstract: A series of peptide nucleic acid-oligo(bicycloguanidinium) (PNA-BGn ) conjugates were synthesized and characterized in terms of cellular antisense activity by using the pLuc750HeLa cell splice correction assay. PNA-BG4 conjugates exhibited low micromolar antisense activity, and their cellular activity required the presence of a hydrophobic silyl terminal protecting group on the oligo(BG) ligand and a minimum of four guanidinium units. Surprisingly, a nonlinear dose-response with an activity threshold around 3-4 μM, indicative of large cooperativity, was observed. Supported by light scattering and electron microscopy analyses, we propose that the activity, and thus cellular delivery, of these lipo-PNA-BG4 conjugates is dependent on self-assembled nanoaggregates. Finally, cellular activity was enhanced by the presence of serum. Therefore we conclude that the lipo-BG-PNA conjugates exhibit an unexpected mechanism for cell delivery and are of interest for further in vivo studies.
authors.affiliation: Institute of Chemical Research of Catalonia. nt Avgda. Països Catalans 16, 43007 Tarragona (Spain).|Present address: LIMES Institute, Chemical Biology and Medicinal Chemistry Unit c/o Kekulé Institute of Organic Chemistry and Biochemistry, Gerhard-Domagk-Strasse 1, 53121 Bonn (Germany).
authors.forename: Julián
authors.initials: J
authors.lastname: Valero
authors.affiliation: Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3c, 2200 Copenhagen N (Denmark).
authors.forename: Takehiko
authors.initials: T
authors.lastname: Shiraishi
authors.affiliation: Institute of Chemical Research of Catalonia. nt Avgda. Països Catalans 16, 43007 Tarragona (Spain).
authors.forename: Javier
authors.initials: J
authors.lastname: de Mendoza
authors.affiliation: Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Blegdamsvej 3c, 2200 Copenhagen N (Denmark). ptrn@sund.ku.dk.
authors.forename: Peter E
authors.initials: PE
authors.lastname: Nielsen
mesh_terms: D001483:Base Sequence; D001692:Biological Transport; D019791:Guanidine / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D053758:Nanoparticles / Q000737:chemistry*; D016376:Oligonucleotides, Antisense / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D020135:Peptide Nucleic Acids / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics
chemical_list: D016376:Oligonucleotides, Antisense; D020135:Peptide Nucleic Acids; D019791:Guanidine
keywords: PNA; antisense activity; nanoaggregates; oligo(bicycloguanidinium); self-assembly