Breaking tumor resistances by broad spectrum assessment of virotherapeutic resistance phenomena

Introduction: Measles vaccine virus (MeV) has proven its oncolytic potential in tumor models and early clinical trials, but primary and secondary resistances often emerge. In order to increase efficiency and to overcome resistance phenomena, a recombinant suicide gene armed MeV vaccine strain (MeV-SCD) was generated, converting the non-toxic prodrug 5-fluorocytosine (5-FC) into the cytotoxic compound 5-fluorouracil (5-FU). Because of its ability to diffuse freely, 5-FU can also kill neighbouring cells which are not infected primarily (“bystander effect”). Aim: We analyzed mechanisms of resistance to MeV-SCD and…