Suicide gene therapy for human oral squamous cell carcinoma cell lines with adeno-associated virus vector

The purpose of this study was to test the possibility of gene transfer as a new therapy for oral cancer. Adeno-associated virus (AAV) has already been used in the fields of cystic fibrosis and Parkinson's disease as a potential vector for gene therapy because of its wide host range, high transduction efficiency, and lack of cytopathogenicity. Four human oral squamous cell carcinoma cell lines were transduced with an AAV vector containing the P-galactosidase gene (AAVlacZ) in vitro. Gene transduction efficiency was from 20 to 50% at a multiplicity of infection (MOI; for the purposes of this study the number of vector genomes per target cell) of 1 x 10(3), and nearly 100% of each cell line were transduced at an MOI of 1 x 10(4). Next, four cell lines were transduced with an AAV vector containing the herpes simplex virus thymidine kinase (HSVtk) gene, which sensitizes transduced cells to ganciclovir (GCV). Subsequent administration of GCV resulted in nearly 100% tumor cell killing at an MOI of 1 x 10(4) and from 70 to 80% tumor cell killing at an MOI of 1 x 10(3). These results suggest that AAV-mediated gene transfer of HSVtk and administration of GCV has potential as a new therapy for oral squamous cell carcinoma. (C) 2001 Elsevier Science Ltd. All rights reserved.