Characterization of a canine glioma cell line as related to established experimental brain tumor models.

A large animal tumor model for anaplastic glioma has been recently developed using immunotolerant allogeneic Beagle dogs and an established canine glioma cell line, J3T. This model offers advantages in terms of tumor morphology and similarity to human anaplastic glioma. The present study was aimed at evaluating the biological characteristics of the J3T canine glioma cell line as related to experimental gene therapy studies. Furthermore, development and morphology of canine brain tumors in a xenogeneic immunodeficient SCID mouse model was investigated. It was demonstrated that cultured J3T cells can be efficiently infected by adenovirus (AV), herpes-simplex type I (HSV), or retrovirus (RV) vectors, as well as by non-virus vectors such as cationic liposome/DNA complexes. Thus, in terms of infectability and transfectability, J3T cells seem to be closer to human glioma than the 9L rodent gliosarcoma. Cytotoxicity of selection antibiotics such as G418, puromycin, and hygromycin on J3T cells essentially resemble cytotoxicity seen with other established glioma lines, for example, 9L, U87, or U343. RV-mediated HSV-TK/GCV gene therapy demonstrated comparable LD50 for TK-expressing and control (non-expressing) J3T and 9L cells treated with Ganciclovir. Further, it was proven that J3T cells are tumorigenic and may grow heterotopically and orthotopically in a xenogeneic immunodeficient host, the SCID mouse, although morphology and growth pattern of these xenogeneic tumors differ from the demonstrated invasive phenotype in the Beagle dog.