Transduction of murine and human tumors using recombinant adenovirus vectors.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
E1-deleted AdV vectors may prove useful in generating tumor vaccines ex vivo with high, transient cytokine expression levels.
Toloza
E M
EM
Division of Surgical Oncology, University of California at Los Angeles School of Medicine 90024, USA.
Hunt
K
K
Miller
A R
AR
McBride
W
W
Lau
R
R
Swisher
S
S
Rhoades
K
K
Arthur
J
J
Choi
J
J
Chen
L
L
Chang
P
P
Chen
A
A
Glaspy
J
J
Economou
J S
JS
D000256:Adenoviridae; D000818:Animals; D005354:Fibrosarcoma / Q000628:therapy; D015870:Gene Expression; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D006652:Histological Techniques; D006801:Humans; D007150:Immunohistochemistry; D007167:Immunotherapy / Q000379:methods; D007376:Interleukin-2 / Q000235:genetics* / Q000627:therapeutic use; D015851:Interleukin-7 / Q000235:genetics* / Q000627:therapeutic use; D008545:Melanoma / Q000628:therapy; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000628:therapy; D014407:Tumor Cells, Cultured
D007376:Interleukin-2; D015851:Interleukin-7