title: Acid-labile pHPMA modification of four-arm oligoaminoamide pDNA polyplexes balances shielding and gene transfer activity in vitro and in vivo.
abstract: We report novel pH-reversibly surface-shielded polyplexes with enhanced gene transfer activity upon systemic administration. A four-arm-structured sequence-defined cationic oligomer KK[HK[(H-Sph-K)3HC]2]2 was designed and synthesized on solid-phase, containing additional lysine residues not only for improved pDNA polyplex stability, but also providing attachment points for subsequent polyplex functionalization with amine-reactive shielding polymers. Herein, the surface of polyplexes was shielded with hydrophilic polymers, monovalent PEG or monovalent and multivalent pHPMA, optionally attached to the polyplex via the acid-labile linker AzMMMan. Overall, surface modification with PEG or pHPMA resulted in a decrease in the zeta potential of polyplexes, consistent with the degree of surface shielding. At pH 6.0, only polyplexes modified via the acid-labile linkage showed an increase in zeta potential, consistent with a "deshielding" in acidic environment, expected as beneficial for endosomal escape. Shielding was more efficient for multivalent pHPMA (20kDa, 30kDa) as compared to monovalent pHPMA (10kDa, 20kDa, 30kDa) or PEG (5kDa). In vitro transfection studies revealed higher gene expression by the polyplexes with the acid-labile shield as compared to their irreversibly shielded counterparts. Intravenous administration of AzMMMan-pHPMA modified polyplexes in an in vivo tumor mouse model mediated enhanced gene expression in the subcutaneous tumor and reduced undesirable expression in the liver.
authors.affiliation: Pharmaceutical Biotechnology, Department of Pharmacy, Butenandtstraße 5-13, Building D, 81377 München, Germany.
authors.forename: Linda
authors.initials: L
authors.lastname: Beckert
authors.affiliation: Centre for Biomacromolecular and Bioanalogous Systems, Department of Biomedicinal Polymers, Institute of Macromolecular Chemistry Academy of Sciences CR, v.v.i., Heyrovskeho sq. 2, Prague, Czech Republic. Electronic address: kostka@imc.cas.cz.
authors.forename: Libor
authors.initials: L
authors.lastname: Kostka
authors.affiliation: Pharmaceutical Biotechnology, Department of Pharmacy, Butenandtstraße 5-13, Building D, 81377 München, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Kessel
authors.affiliation: Pharmaceutical Biotechnology, Department of Pharmacy, Butenandtstraße 5-13, Building D, 81377 München, Germany.
authors.forename: Ana
authors.initials: A
authors.lastname: Krhac Levacic
authors.affiliation: Centre for Biomacromolecular and Bioanalogous Systems, Department of Biomedicinal Polymers, Institute of Macromolecular Chemistry Academy of Sciences CR, v.v.i., Heyrovskeho sq. 2, Prague, Czech Republic.
authors.forename: Hana
authors.initials: H
authors.lastname: Kostkova
authors.affiliation: Centre for Biomacromolecular and Bioanalogous Systems, Department of Biomedicinal Polymers, Institute of Macromolecular Chemistry Academy of Sciences CR, v.v.i., Heyrovskeho sq. 2, Prague, Czech Republic.
authors.forename: Tomas
authors.initials: T
authors.lastname: Etrych
authors.affiliation: Pharmaceutical Biotechnology, Department of Pharmacy, Butenandtstraße 5-13, Building D, 81377 München, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lächelt
authors.affiliation: Pharmaceutical Biotechnology, Department of Pharmacy, Butenandtstraße 5-13, Building D, 81377 München, Germany. Electronic address: ernst.wagner@cup.uni-muenchen.de.
authors.forename: Ernst
authors.initials: E
authors.lastname: Wagner
mesh_terms: D000577:Amides / Q000737:chemistry*; D000818:Animals; D004247:DNA / Q000737:chemistry*; D018014:Gene Transfer Techniques; D066298:In Vitro Techniques; D008689:Methacrylates / Q000737:chemistry*; D051379:Mice
chemical_list: D000577:Amides; D008689:Methacrylates; D004247:DNA; C032802:hydroxypropyl methacrylate
keywords: AzMMMan; Non-viral gene delivery; PEG; Plasmid DNA; pH-sensitive shielding; pHPMA