title: Adenoviral vectors coated with PAMAM dendrimer conjugates allow CAR independent virus uptake and targeting to the EGF receptor.
abstract: Adenovirus type 5 (Ad) is an efficient gene vector with high gene transduction potential, but its efficiency depends on its native cell receptors coxsackie- and adenovirus receptor (CAR) for cell attachment and α(v)β(3/5) integrins for internalization. To enable transduction of CAR negative cancer cell lines, we have coated the negatively charged Ad by noncovalent charge interaction with cationic PAMAM (polyamidoamine) dendrimers. The specificity for tumor cell infection was increased by targeting the coated Ad to the epidermal growth factor receptor using the peptide ligand GE11, which was coupled to the PAMAM dendrimer via a 2 kDa PEG spacer. Particles were examined by measuring surface charge and size, the degree of coating was determined by transmission electron microscopy. The net positive charge of PAMAM coated Ad enhanced cellular binding and uptake leading to increased transduction efficiency, especially in low to medium CAR expressing cancer cell lines using enhanced green fluorescent protein or luciferase as transgene. While PAMAM coated Ad allowed for efficient internalization, coating with linear polyethylenimine induced excessive particle aggregation, elevated cellular toxicity and lowered transduction efficiency. PAMAM coating of Ad enabled successful transduction of cells in vitro even in the presence of neutralizing antibodies. Taken together, this study clearly proves noncovalent, charge-based coating of Ad vectors with ligand-equipped dendrimers as a viable strategy for efficient transduction of cells otherwise refractory to Ad infection.
authors.affiliation: Center for System Based Drug Research, Department of Pharmacy, LMU Munich, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Vetter
authors.forename: Kulpreet S
authors.initials: KS
authors.lastname: Virdi
authors.forename: Sigrid
authors.initials: S
authors.lastname: Espenlaub
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Rödl
authors.forename: Ernst
authors.initials: E
authors.lastname: Wagner
authors.forename: Per S
authors.initials: PS
authors.lastname: Holm
authors.forename: Christina
authors.initials: C
authors.lastname: Scheu
authors.forename: Florian
authors.initials: F
authors.lastname: Kreppel
authors.forename: Christine
authors.initials: C
authors.lastname: Spitzweg
authors.forename: Manfred
authors.initials: M
authors.lastname: Ogris
mesh_terms: D000256:Adenoviridae; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein / Q000235:genetics / Q000378:metabolism*; D050091:Dendrimers / Q000737:chemistry*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D005822:Genetic Vectors / Q000737:chemistry*; D006801:Humans; D046529:Microscopy, Electron, Transmission
chemical_list: D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D050091:Dendrimers; C104700:PAMAM Starburst; D066246:ErbB Receptors