In vivo bystander effect in the intracranial model with rat glioma cells reflects the clonal difference of HSV-TK positive cells
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- Published online on: September 1, 1996 https://doi.org/10.3892/ijo.9.3.521
- Pages: 521-525
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Abstract
We have investigated clonal variations on the in vivo bystander effect of herpes simplex virus-thymidine kinase (HSV-TK)/ganciclovir (GCV) system, using an intracranial tumor model with 9L rat gliosarcoma cells. For this purpose, we established three 9L clones transduced with HSV-TK gene (9L-TK), each of which had similar TK activity but showed different tumor growth rate in vivo. The use of GCV in vitro confirmed previous reports that the bystander effect was manifest in a confluent culture condition, but not in a low cell density condition. In contrast, the therapeutic benefit of the in vivo bystander effect varied among each 9L-TK clone, and had a positive correlation with the in vivo growth rate of the clone. Thus, the bystander effect seems to reflect the growth rate of TK-positive cells, and these data raise a crucial point for applying the bystander effect to clinical trials.
