title: In vitro characterization of two novel biodegradable vectors for the delivery of radiolabeled antisense oligonucleotides.
abstract: The development of antisense oligonucleotides suitable for tumor targeting applications is hindered by low stability and bioavailability of oligonucleotides in vivo and by the absence of efficient and safe vectors for oligonucleotide delivery. Stabilization in vivo has been achieved through chemical modification of oligonucleotides by various means, but effective approaches to enhance their intracellular delivery are lacking. This study reports on the characterization in vitro of a fully phosphorothioated 20-mer oligonucleotide, complementary to p21 mRNA, radiolabeled with fluorine-18 using a thiol reactive prosthetic group. The potential of two novel synthetic block copolymers containing grafted polyamines on their hydrophobic blocks for vector-assisted cell delivery was studied in vitro. Extensive cellular uptake studies were performed in human colon carcinoma cell lines with enhanced or deficient p21 expression to evaluate and compare the uptake mechanism of naked and vectorized radiolabeled formulations. Uptake studies with the two novel biodegradable vectors showed a moderate increase in cell uptake of the radiofluorinated antisense oligonucleotide. The two vectors show, however, promising advantages over conventional lipidic vectors regarding their biocompatibility and subcellular distribution.
authors.affiliation: Department of Nuclear Medicine, Innsbruck Medical University, Austria.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: von Guggenberg
authors.forename: Soraya
authors.initials: S
authors.lastname: Shahhosseini
authors.forename: Ingrid
authors.initials: I
authors.lastname: Koslowsky
authors.forename: Afsaneh
authors.initials: A
authors.lastname: Lavasanifar
authors.forename: David
authors.initials: D
authors.lastname: Murray
authors.forename: John
authors.initials: J
authors.lastname: Mercer
mesh_terms: D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis; D005029:Ethylenediamines / Q000737:chemistry; D005462:Fluorine Radioisotopes / Q000737:chemistry*; D005720:Gamma Rays; D015870:Gene Expression / Q000528:radiation effects; D018014:Gene Transfer Techniques; D045325:HCT116 Cells; D006801:Humans; D007553:Isotope Labeling; D007783:Lactones / Q000737:chemistry; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics; D010714:Phosphatidylethanolamines / Q000737:chemistry; D054735:Phosphorothioate Oligonucleotides / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D019275:Radiopharmaceuticals / Q000008:administration & dosage / Q000737:chemistry; D013096:Spermine / Q000737:chemistry
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D005029:Ethylenediamines; D005462:Fluorine Radioisotopes; D007783:Lactones; D016376:Oligonucleotides, Antisense; D010714:Phosphatidylethanolamines; D054735:Phosphorothioate Oligonucleotides; D011108:Polymers; D019275:Radiopharmaceuticals; C473831:poly(ethylene oxide)-b-poly(caprolactone); D013096:Spermine; D011092:Polyethylene Glycols; C020888:1,2-dielaidoylphosphatidylethanolamine; C034269:tetraethylenepentamine