title: Expression of p53, or targeting towards EGFR, enhances the oncolytic potency of conditionally replicative adenovirus against neuroblastoma.
abstract: BACKGROUND
  Advanced stage and relapsing neuroblastoma (NB) has a poor prognosis with frequent treatment failures, warranting new treatment options and enhanced local tumor control. Treatment with conditionally replicative adenoviruses (CRAds) has shown effectiveness in various preclinical cancer models, but has not yet been evaluated for local control of NB. Here, we tested the efficacy of the CRAd AdDelta24 and of two AdDelta24 derivatives against NB. Derivative AdDelta24-425S11 infects cells deficient in coxsackie/adenovirus receptor (CAR) via the epidermal growth factor receptor (EGFR). Derivative AdDelta24-p53 expresses the tumor suppressor protein p53 to promote oncolysis.
  
  
  METHODS
  Expression of CAR and EGFR, and p53 pathway and DNA damage responses were analyzed in six NB cell lines and two xenografts derived from primary NB using immunohistochemistry, reporter gene transactivation, Western blot and fluorescence-activated cell sorting (FACS) analysis. Efficacy of AdDelta24, AdDelta24-425S11 and AdDelta24-p53 against NB was evaluated in vitro by cell viability analysis and in vivo by monitoring subcutaneous xenograft tumor growth in mice and by histological analysis of treated tumors.
  
  
  RESULTS
  Neuroblastoma cell lines were sensitive to oncolysis by AdDelta24, with a higher susceptibility of those with functional p53 and intact DNA damage responses. Compared to AdDelta24, AdDelta24-p53 exhibited enhanced oncolytic potency on all NB cell lines independent of their p53 status and AdDelta24-425S11 was more effective against CAR-low IGR-NB8 cells. Moreover, five daily intratumoral injections of 10(8) plaque-forming units (pfu) of AdDelta24-p53 or AdDelta24-425S11 into subcutaneous IGR-NB8 and IGR-N91 xenografts at an advanced tumor stage yielded significant tumor growth delays (TGD). In contrast, at this dose, AdDelta24 did not cause significant TGD of neuroblastoma xenografts. Injection of AdDelta24-p53 was associated with extensive cell lysis, apoptotic cell death, and fibrous fascicles in the tumors.
  
  
  CONCLUSIONS
  CRAds expressing p53 and targeted towards EGFR appear promising new agents for local control in the treatment of neuroblastoma.
authors.affiliation: Department of Pediatrics, Institut Gustave Roussy, 94805 Villejuif, France. geoerger@igr.fr
authors.forename: Birgit
authors.initials: B
authors.lastname: Geoerger
authors.forename: Victor W
authors.initials: VW
authors.lastname: van Beusechem
authors.forename: Paule
authors.initials: P
authors.lastname: Opolon
authors.forename: Jackie
authors.initials: J
authors.lastname: Morizet
authors.forename: Lysiane
authors.initials: L
authors.lastname: Laudani
authors.forename: Yann
authors.initials: Y
authors.lastname: Lecluse
authors.forename: Michel
authors.initials: M
authors.lastname: Barrois
authors.forename: Sander
authors.initials: S
authors.lastname: Idema
authors.forename: Jacques
authors.initials: J
authors.lastname: Grill
authors.forename: Winald R
authors.initials: WR
authors.lastname: Gerritsen
authors.forename: Gilles
authors.initials: G
authors.lastname: Vassal
mesh_terms: D000256:Adenoviridae / Q000502:physiology*; D000818:Animals; D017209:Apoptosis; D001932:Brain Neoplasms / Q000235:genetics / Q000628:therapy / Q000821:virology; D003588:Cytopathogenic Effect, Viral / Q000502:physiology; D004249:DNA Damage; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D018390:Gene Targeting; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000008:administration & dosage / Q000627:therapeutic use; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009447:Neuroblastoma / Q000628:therapy* / Q000821:virology; D011991:Receptors, Virus / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D014779:Virus Replication; D023041:Xenograft Model Antitumor Assays
chemical_list: D011991:Receptors, Virus; D016159:Tumor Suppressor Protein p53; C085301:adenovirus receptor; D066246:ErbB Receptors