title: Efficient and selective gene transfer into primary human brain tumors by using single-chain antibody-targeted adenoviral vectors with native tropism abolished.
abstract: The application of adenoviral vectors in cancer gene therapy is hampered by low receptor expression on tumor cells and high receptor expression on normal epithelial cells. Targeting adenoviral vectors toward tumor cells may improve cancer gene therapy procedures by providing augmented tumor transduction and decreased toxicity to normal tissues. Targeting requires both the complete abolition of native tropism and the addition of a new specific binding ligand onto the viral capsid. Here we accomplished this by using doubly ablated adenoviral vectors, lacking coxsackievirus-adenovirus receptor and alpha(v) integrin binding capacities, together with bispecific single-chain antibodies targeted toward human epidermal growth factor receptor (EGFR) or the epithelial cell adhesion molecule. These vectors efficiently and selectively targeted both alternative receptors on the surface of human cancer cells. Targeted doubly ablated adenoviral vectors were also very efficient and specific with primary human tumor specimens. With primary glioma cell cultures, EGFR targeting augmented the median gene transfer efficiency of doubly ablated adenoviral vectors 123-fold. Moreover, EGFR-targeted doubly ablated vectors were selective for human brain tumors versus the surrounding normal brain tissue. They transduced organotypic glioma and meningioma spheroids with efficiencies similar to those of native adenoviral vectors, while exhibiting greater-than-10-fold-reduced background levels on normal brain explants from the same patients. As a result, EGFR-targeted doubly ablated adenoviral vectors had a 5- to 38-fold-improved tumor-to-normal brain targeting index compared to native vectors. Hence, single-chain targeted doubly ablated adenoviral vectors are promising tools for cancer gene therapy. They should provide an improved therapeutic index with efficient tumor transduction and effective protection of normal tissue.
authors.affiliation: Division of Gene Therapy, Department of Medical Oncology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands. vw.van_beusechem.oncol@med.vu.nl
authors.forename: Victor W
authors.initials: VW
authors.lastname: van Beusechem
authors.forename: Jacques
authors.initials: J
authors.lastname: Grill
authors.forename: D C Jeroen
authors.initials: DC
authors.lastname: Mastenbroek
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wickham
authors.forename: Peter W
authors.initials: PW
authors.lastname: Roelvink
authors.forename: Hidde J
authors.initials: HJ
authors.lastname: Haisma
authors.forename: Martine L M
authors.initials: ML
authors.lastname: Lamfers
authors.forename: Clemens M F
authors.initials: CM
authors.lastname: Dirven
authors.forename: Herbert M
authors.initials: HM
authors.lastname: Pinedo
authors.forename: Winald R
authors.initials: WR
authors.lastname: Gerritsen
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D000818:Animals; D018033:Antibodies, Bispecific / Q000378:metabolism; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D066246:ErbB Receptors / Q000276:immunology / Q000378:metabolism; D018390:Gene Targeting; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics; D009154:Mutation; D051381:Rats; D011991:Receptors, Virus / Q000235:genetics; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D018033:Antibodies, Bispecific; C568771:CLMP protein, human; C568773:Clmp protein, rat; D062727:Coxsackie and Adenovirus Receptor-Like Membrane Protein; D008164:Luminescent Proteins; D011991:Receptors, Virus; D049452:Green Fluorescent Proteins; D066246:ErbB Receptors