Toloza E M, Hunt K, Miller A R, McBride W, Lau R, Swisher S, Rhoades K, Arthur J, Choi J, Chen L, Chang P, Chen A, Glaspy J, Economou J S
Division of Surgical Oncology, University of California at Los Angeles School of Medicine 90024, USA.
Ann Surg Oncol. 1997 Jan;4(1):70-9. doi: 10.1007/BF02316813.
Most cytokine-based cancer gene therapy clinical trials have used labor-intensive, retrovirus-mediated strategies resulting in unpredictable gene expression. Recombinant AdV vectors were evaluated for easier, more reproducible gene transfer into 12 human melanoma, 2 murine fibrosarcomas, and 8 other tumor cell lines.
AdV vectors contained a reporter (Escherichia coli beta-galactosidase or firefly luciferase) or cytokine gene (human interleukin-2 [IL-2] or IL-7). Transduction efficiencies and expression levels were assessed by histochemical staining, flow cytometry, polymerase chain reaction, fluorometry, and enzyme-linked immunosorbent assay. Tumorigenicity was determined by subcutaneous injection of cells into syngeneic mice.
All cell lines studied were transduced with AdV. Most cell lines exhibited 100% transduction efficiencies (by flow cytometry) at multiplicities of infection (MOI) epsilon 10. Gene expression correlated linearly with MOI, but a cytopathic effect was observed at MOI > 100 with all vectors. Nanogram gene expression levels were routinely achieved. Irradiation (30 Gy) minimally affected expression levels. Tumorigenicity of AdV-IL-2-transduced fibrosarcoma cells in mice was inversely related to IL-2 production. A majority of mice that rejected their tumor challenge were immune to tumor rechallenge.
E1-deleted AdV vectors may prove useful in generating tumor vaccines ex vivo with high, transient cytokine expression levels.
