title: Ephrin A2 receptor targeting does not increase adenoviral pancreatic cancer transduction in vivo.
abstract: OBJECTIVE
  To generate an adenoviral vector specifically targeting the EphA2 receptor (EphA2R) highly expressed on pancreatic cancer cells in vivo.
  
  
  METHODS
  YSA, a small peptide ligand that binds the EphA2R with high affinity, was inserted into the HI loop of the adenovirus serotype 5 fiber knob. To further increase the specificity of this vector, binding sites for native adenoviral receptors, the coxsackie and adenovirus receptor (CAR) and integrin, were ablated from the viral capsid. The ablated retargeted adenoviral vector was produced on 293T cells. Specific targeting of this novel adenoviral vector to pancreatic cancer was investigated on established human pancreatic cancer cell lines. Upon demonstrating specific in vitro targeting, in vivo targeting to subcutaneous growing human pancreatic cancer was tested by intravenous and intraperitoneal administration of the ablated adenoviral vector.
  
  
  RESULTS
  Ablation of native cellular binding sites reduced adenoviral transduction at least 100-fold. Insertion of the YSA peptide in the HI loop restored adenoviral transduction of EphA2R-expressing cells but not of cells lacking this receptor. YSA-mediated transduction was inhibited by addition of synthetic YSA peptide. The transduction specificity of the ablated retargeted vector towards human pancreatic cancer cells was enhanced almost 10-fold in vitro. In a subsequent in vivo study in a nude (nu/nu) mouse model however, no increased adenoviral targeting to subcutaneously growing human pancreas cancer nodules was seen upon injection into the tail vein, nor upon injection into the peritoneum.
  
  
  CONCLUSIONS
  Targeting the EphA2 receptor increases specificity of adenoviral transduction of human pancreatic cancer cells in vitro but fails to enhance pancreatic cancer transduction in vivo.
authors.affiliation: Liver Center AMC, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Michael A
authors.initials: MA
authors.lastname: van Geer
authors.forename: Conny T
authors.initials: CT
authors.lastname: Bakker
authors.forename: Naoya
authors.initials: N
authors.lastname: Koizumi
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Mizuguchi
authors.forename: John G
authors.initials: JG
authors.lastname: Wesseling
authors.forename: Ronald P J
authors.initials: RP
authors.lastname: Oude Elferink
authors.forename: Piter J
authors.initials: PJ
authors.lastname: Bosma
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D036104:Receptor, EphA2 / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic
chemical_list: D036104:Receptor, EphA2