Adenoviral-mediated gene transfer into the canine brain in vivo.
OBJECTIVE
Glioblastoma multiforme (GBM) is a devastating brain tumor for which there is no cure. Adenoviral-mediated transfer of conditional cytotoxic (herpes simplex virus [HSV] 1-derived thymidine kinase [TK]) and immunostimulatory (Fms-like tyrosine kinase 3 ligand [Flt3L]) transgenes elicited immune-mediated long-term survival in a syngeneic intracranial GBM model in rodents. However, the lack of a large GBM animal model makes it difficult to predict the outcome of therapies in humans. Dogs develop spontaneous GBM that closely resemble the human disease; therefore, they constitute an excellent large animal model. We assayed the transduction efficiency of adenoviral vectors (Ads) encoding beta-galactosidase (betaGal), TK, and Flt3L in J3T dog GBM cells in vitro and in the dog brain in vivo.


METHODS
J3T cells were infected with Ads (30 plaque-forming units/cell; 72 h) encoding betaGal (Ad-betaGal), TK (Ad-TK), or Flt3L (Ad-Flt3L). We determined transgene expression by immunocytochemistry, betaGal activity, Flt3L enzyme-linked immunosorbent assay, and TK-induced cell death. Ads were also injected intracranially into the parietal cortex of healthy dogs. We determined cell-type specific transgene expression and immune cell infiltration.


RESULTS
Adenoviral-mediated gene transfer of HSV1-TK, Flt3L, and betaGal was detected in dog glioma cells in vitro (45% transduction efficiency) and in the dog brain in vivo (10-mm area transduced surrounding each injection site). T cells and macrophages/activated microglia infiltrated the injection sites. Importantly, no adverse clinical or neuropathological side effects were observed.


CONCLUSIONS
We demonstrate effective adenoviral-mediated gene transfer into the brain of dogs in vivo and support the use of these vectors to develop an efficacy trial for canine GBM as a prelude to human trials.
Candolfi
Marianela
M
Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.
Kroeger
Kurt M
KM
Pluhar
G Elizabeth
GE
Bergeron
Josee
J
Puntel
Mariana
M
Curtin
James F
JF
McNiel
Elizabeth A
EA
Freese
Andrew B
AB
Ohlfest
John R
JR
Moore
Peter
P
Lowenstein
Pedro R
PR
Castro
Maria G
MG
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D001921:Brain / Q000502:physiology*; D001932:Brain Neoplasms / Q000235:genetics; D004195:Disease Models, Animal; D004285:Dogs; D018014:Gene Transfer Techniques; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D014407:Tumor Cells, Cultured