1. ¹Department of Radiation Oncology, Universitätsklinikum Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68135 Mannheim, Germany
2. ²German Cancer Research Center, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany
3. ³Department of Dermatology, Heinrich-Heine-University, Moorenstrae 5, D-40225, Duesseldorf, Germany
4. ⁴Department of Internal Medicine V, University of Heidelberg, Hospitalstrasse 3, D-69115 Heidelberg, Germany

Correspondence: Dr Stefan Fruehauf, Department of Internal Medicine V, University of Heidelberg, Hospitalstrae 3, Heidelberg D-69115, Germany. E-mail: stefan_fruehauf@med.uni-heidelberg.de

Received 1 October 2003.

Abstract

Soft-tissue sarcomas are mesenchymal tumors that respond poorly to systemic chemotherapy. Suicide gene therapy may be an alternative treatment strategy. Here we show a high susceptibility of human sarcoma cell lines for recombinant adeno-associated virus 2 (rAAV-2) suicide vectors: connective tissue sarcoma (HS-1), fibrosarcoma (HT-1080), Ewing sarcoma (RD-ES), Askin tumor (SK-N-MC), rhabdomyosarcoma (A-204) and soft-tissue sarcoma (WSKL-1). Several vectors containing the thymidine kinase (TK) gene under the control of either the cytomegalovirus promoter or the elongation-factor 1 alpha (EF1) promoter were cloned and tested. Higher expression levels of the transgene were observed in the sarcoma lines when using the EF1-suicide gene-containing vectors. A complete eradication of rAAV-2-EF1-TK/eGFP (TK/enhanced green fluorescent protein fusion gene)-transduced tumor cells was shown following exposure to ganciclovir (2.5 g/ml) in vitro, while at this dose level >90% of mock-transduced tumor cells survived. Xenotransplantation tumor models (intraperitoneal, subcutaneous) for the human sarcoma cell line HS-1 were established in nonobese diabetic/severe-combined immunodeficient mice. Mice transplanted with rAAV-2-EF1-TK/eGFP-transduced and ganciclovir-exposed tumor cells survived >5 months while in the nontransduced group all mice had died approximately 1 month after inoculation. These data hold promise for further development of rAAV-2-based suicide gene therapy of sarcomas.