title: The organotypic multicellular spheroid is a relevant three-dimensional model to study adenovirus replication and penetration in human tumors in vitro.
abstract: The use of adenoviruses for gene transfer and as oncolytic agents is currently receiving widespread attention. As specific constraints to adenovirus distribution and spread cannot be studied in cell cultures, there is a need for an in vitro three-dimensional (3D) model mimicking the in vivo biology of tumors. We studied the interactions between tumor and adenoviruses using multicellular spheroids grown from primary brain tumor material. Using beta-galactosidase and luciferase reporter genes expressed by replication-defective adenoviruses, we showed that infection was restricted to the first layer of cells. Using a replication-competent adenovirus expressing the luciferase gene, we showed that transgene expression in the spheroid was considerably enhanced and that viral spreading deep into the 3D structure took place. In addition, a tetrazolium salt-based metabolic assay could be used to compare the oncolytic activity of different concentrations of replication-competent adenoviruses. We can conclude that organotypic spheroids offer a versatile in vitro system for studying distribution, spread, and oncolysis by adenoviruses in a clinically relevant model.
authors.affiliation: Division of Gene Therapy, Department of Medical Oncology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jacques
authors.initials: J
authors.lastname: Grill
authors.forename: Martine L M
authors.initials: ML
authors.lastname: Lamfers
authors.forename: Victor W
authors.initials: VW
authors.lastname: van Beusechem
authors.forename: Clemens M
authors.initials: CM
authors.lastname: Dirven
authors.forename: D Shareen
authors.initials: DS
authors.lastname: Pherai
authors.forename: Mathijs
authors.initials: M
authors.lastname: Kater
authors.forename: Paul
authors.initials: P
authors.lastname: Van der Valk
authors.forename: Ronald
authors.initials: R
authors.lastname: Vogels
authors.forename: W Peter
authors.initials: WP
authors.lastname: Vandertop
authors.forename: Herbert M
authors.initials: HM
authors.lastname: Pinedo
authors.forename: David T
authors.initials: DT
authors.lastname: Curiel
authors.forename: Winald R
authors.initials: WR
authors.lastname: Gerritsen
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D001932:Brain Neoplasms / Q000378:metabolism; D002455:Cell Division; D006801:Humans; D007150:Immunohistochemistry; D008156:Luciferases / Q000235:genetics; D009369:Neoplasms / Q000473:pathology*; D018874:Spheroids, Cellular / Q000473:pathology*; D013778:Tetrazolium Salts / Q000494:pharmacology; D013997:Time Factors; D019076:Transgenes; D014407:Tumor Cells, Cultured
chemical_list: D013778:Tetrazolium Salts; D008156:Luciferases