In vitro screening of clinical drugs identifies sensitizers of oncolytic viral therapy in glioblastoma stem-like cells

Gene Ther. 2015 Dec;22(12):947-59. doi: 10.1038/gt.2015.72. Epub 2015 Jul 21.


Oncolytic viruses (OV) have broad potential as an adjuvant for the treatment of solid tumors. The present study addresses the feasibility of clinically applicable drugs to enhance the oncolytic potential of the OV Delta24-RGD in glioblastoma. In total, 446 drugs were screened for their viral sensitizing properties in glioblastoma stem-like cells (GSCs) in vitro. Validation was done for 10 drugs to determine synergy based on the Chou Talalay assay. Mechanistic studies were undertaken to assess viability, replication efficacy, viral infection enhancement and cell death pathway induction in a selected panel of drugs. Four viral sensitizers (fluphenazine, indirubin, lofepramine and ranolazine) were demonstrated to reproducibly synergize with Delta24-RGD in multiple assays. After validation, we underscored general applicability by testing candidate drugs in a broader context of a panel of different GSCs, various solid tumor models and multiple OVs. Overall, this study identified four viral sensitizers, which synergize with Delta24-RGD and two other strains of OVs. The viral sensitizers interact with infection, replication and cell death pathways to enhance efficacy of the OV.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain Neoplasms / drug therapy
  • Brain Neoplasms / therapy
  • Brain Neoplasms / virology
  • Cell Line, Tumor
  • Drug Evaluation, Preclinical
  • Fluphenazine / pharmacology
  • Glioblastoma / drug therapy
  • Glioblastoma / therapy*
  • Glioblastoma / virology
  • HCT116 Cells
  • Humans
  • Indoles / pharmacology
  • Neoplastic Stem Cells / drug effects*
  • Neoplastic Stem Cells / virology*
  • Oncolytic Virotherapy / methods*
  • Oncolytic Viruses / drug effects*
  • Oncolytic Viruses / physiology
  • Virus Replication / drug effects


  • Indoles
  • Fluphenazine
  • indirubin