Gene therapy of chondrosarcoma using retrovirus vectors encoding the herpes simplex virus thymidine kinase gene

Human chondrosarcoma cells (HCS-TG) were transduced with the gene for a her pes simplex virus thymidine kinase (HSV-tk) or Escherichia coli beta-galact osidase (lacZ). We investigated the cytotoxicity of human chondrosarcoma be aring an HSV-tk gene after treatment with ganciclovir. Chondrosarcoma cells bearing an HSV-tk gene were more sensitive than non-transduced cells. Cocu lturing with chondrosarcoma cells bearing both an HSV-tk gene (HCS-TG-tk) a nd lacZ gene (HCS-TG-Z) in various ratios showed a bystander effect. Chondr osarcoma implanted in nude mice were injected with HCS-TG-tk cells. After 4 weeks, the growth of tumors was significantly prevented.