title: Oncolytic virotherapy of meningiomas in vitro with replication-competent adenovirus.
abstract: OBJECTIVE
  To evaluate the efficacy of the conditionally replicating adenovirus (Ad) Ad.d24 for oncolysis of benign and malignant meningiomas.
  
  
  METHODS
  Primary meningioma cells and organotypic spheroids were cultured from tumor biopsies of 12 consecutive unselected patients. Four different Ads were constructed and tested on meningioma cells and spheroids: a replication-deficient Ad encoding the luciferase marker gene (Ad.Luc), a replication-competent Ad with complete E1 region (Ad.E1+), a replication-competent Ad encoding the luciferase gene in the E3 region (Ad.E1Luc), and a conditionally replicating Ad with an E1ACR2 deletion (Ad.d24). Replication of the latter is restricted to cells with a defective retinoblastoma pathway, whereas Ad.E1+ and Ad.E1Luc can replicate in all human cells like a wild-type Ad. Their oncolytic activity was compared in primary meningioma cells and spheroids by use of viability and outgrowth assays.
  
  
  RESULTS
  Adenoviral penetration into organotypic meningioma spheroids was detected with the replication-competent Ad.E1Luc, whereas infection with the replication-deficient Ad.Luc was limited to the outer layer of the spheroid. Replication of the Ads and oncolysis was demonstrated in primary cell cultures of meningioma cells at high dose, i.e., greater than 50 plaque-forming units per cell. At a lower dose of 5 plaque-forming units per cell, Ad.d24 kills meningioma cells more efficiently than Ad.E1+. Infection of organotypic meningioma spheroids with Ad.d24 resulted in decreased viability and suppression of outgrowth as compared with untreated control spheroids.
  
  
  CONCLUSIONS
  Infection of meningioma cells and spheroids with replication-competent Ads results in efficient oncolysis. The Ad modified to replicate selectively in retinoblast-mutant cells, Ad.d24, seemed to be an efficient oncolytic agent in benign, atypical, and malignant meningiomas.
authors.affiliation: Department of Medical Oncology, Division of Gene Therapy, Vrije Universiteit 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: Paul
authors.initials: P
authors.lastname: van der Valk
authors.forename: Anne
authors.initials: A
authors.lastname: Huisman
authors.forename: Peter
authors.initials: P
authors.lastname: Sminia
authors.forename: Ramon
authors.initials: R
authors.lastname: Alemany
authors.forename: David T
authors.initials: DT
authors.lastname: Curiel
authors.forename: W Peter
authors.initials: WP
authors.lastname: Vandertop
authors.forename: Winald R
authors.initials: WR
authors.lastname: Gerritsen
authors.forename: Clemens M F
authors.initials: CM
authors.lastname: Dirven
mesh_terms: D000256:Adenoviridae / Q000502:physiology; D000328:Adult; D000368:Aged; D002478:Cells, Cultured; D006801:Humans; D008579:Meningioma / Q000628:therapy*; D008875:Middle Aged; D050130:Oncolytic Virotherapy / Q000379:methods; D014779:Virus Replication