Gene therapy of rat 9L gliosarcoma tumors by transduction with selectable genes does not require drug selection.

Publication Type:

Journal Article


Proceedings of the National Academy of Sciences of the United States of America, Volume 91, Issue 17, p.8185-9 (1994)


1994, Animals, Cell Division, CYTOMEGALOVIRUS, Ganciclovir, Gene Therapy, Genetic Vectors, Gliosarcoma, Humans, Kanamycin Kinase, Kinetics, Male, Moloney murine leukemia virus, Phosphotransferases (Alcohol Group Acceptor), Plasmids, Rats, Rats, Inbred F344, Recombinant Fusion Proteins, Simplexvirus, Thymidine Kinase, Transduction, Genetic, Transfection, Tumor Cells, Cultured


9L rat glioma cells have been used as a model for brain tumor therapies. It has been reported that in vivo infection of 9L cells with a replication-defective retrovirus expressing the herpes simplex thymidine kinase gene resulted in decreased tumor formation following treatment with the antiviral drug ganciclovir. In the study reported here, rats were injected either intracerebrally or subcutaneously with 9L glioma cells expressing a chimeric hygromycin phosphotransferase-thymidine kinase fusion protein or with unmodified 9L cells. Tumor formation was decreased in the rats receiving modified cells, even in the absence of treatment with ganciclovir. Suppression of tumor growth was also observed with cells modified to express the intracellular selectable marker neomycin phosphotransferase. These results indicate that an intracellular selectable marker, in the absence of pharmacologic selection, can inhibit tumor growth of 9L cells. The demonstration that intracellular marker genes can negatively influence the survival of transplanted cells has important implications for in vivo studies that use genetically modified cells.