title: Integrin alphaVbeta3 targeted gene delivery using RGD peptidomimetic conjugates with copolymers of PEGylated poly(ethylene imine).
abstract: This study describes the synthesis and characterization of five conjugates of poly(ethylene glycol) modified polyethylenimine (PEG-PEIs) coupled in two different synthesis routes to a nonpeptidic pentacyclic RDG-mimetic for integrin receptor-targeted gene delivery. Synthesis of this panel of different conjugates allowed for systematic analysis of structure-activity relationships. Conjugates were therefore characterized regarding molecular composition, DNA condensation, size, and zeta potential of self-assembled polyplexes. In vitro characterization included investigation of blood compatibility, binding affinity to receptor-positive and receptor-negative cells measured by flow cytometry, cellular uptake quantified by scintillation counting, and efficiency and specificity of transfection assayed by reporter gene expression. In a first synthetic approach, low molecular weight PEI (LMW-PEI) was PEGylated using a heterobifunctional PEG linker and coupling of the RGD-mimetic was achieved at the distal end of PEG chains. In a second synthesis route, the RGD-mimetic was directly coupled to AB-block-copolymers of PEI (25 kDa) and PEG (30 kDa). Interactions of RGD-PEG-LMW-PEI conjugates with DNA were strongly impaired, whereas PEG-PEI-RGD conjugates were more promising candidates due to their physicochemical properties and higher receptor specificity. The binding, uptake, and transfection efficiency in receptor-positive cells was strongly increased upon conjugation of the RGD-mimetic to AB-block-copolymers of PEG-PEI and depended on the degree of peptide substitution. The conjugates of PEG-PEI AB-block-copolymers with low ligand density of the RGD-mimetic appear to be promising candidates for in vivo cancer gene therapy.
authors.affiliation: Department of Pharmaceutics and Biopharmacy, Philipps-Universitat Marburg, Ketzerbach 63, 35032 Marburg, Germany.
authors.forename: Olivia M
authors.initials: OM
authors.lastname: Merkel
authors.forename: Oliver
authors.initials: O
authors.lastname: Germershaus
authors.forename: Carol K
authors.initials: CK
authors.lastname: Wada
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Tarcha
authors.forename: Thomas
authors.initials: T
authors.lastname: Merdan
authors.forename: Thomas
authors.initials: T
authors.lastname: Kissel
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D040761:Biomimetic Materials / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D045744:Cell Line, Tumor; D004247:DNA / Q000378:metabolism; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D008024:Ligands; D008301:Maleimides / Q000737:chemistry; D009842:Oligopeptides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D011094:Polyethyleneimine / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014162:Transfection
chemical_list: D001672:Biocompatible Materials; D039302:Integrin alphaVbeta3; D008024:Ligands; D008301:Maleimides; D009842:Oligopeptides; D011422:Propionates; D013438:Sulfhydryl Compounds; C043592:maleimide; D011092:Polyethylene Glycols; C047981:arginyl-glycyl-aspartic acid; D011094:Polyethyleneimine; D004247:DNA; C029658:propionic acid