The inhibitory effects of interferon gamma on the growth of bladder cancer cells.

The inhibitory effect of interferon-gamma on the growth of three human bladder cancer cell lines, RT4, RT112 and MGH-U1, representing tumour grades 1, 2 and 3 respectively, was studied. The effects of 10, 100 and 1000 Uml.-1 of interferon-gamma on cell numbers and thymidine incorporation were measured at 24 hour intervals up to a maximum of seven days. Morphological appearances were also studied. Each line was susceptible to the growth inhibitory effects of interferon-gamma and this was both dose and time dependent. The effects of interferon-gamma, on the RT4 and RT112 cells were apparent from 24 hours, and were both cytostatic and cytotoxic in nature, whereas the effects on MGH-U1 cells were seen from 48 hours onwards and were only cytostatic. Cytological changes occurred in all three cell lines, being most pronounced in RT112. The growth of bladder cancer cells was inhibited by interferon-gamma, and in this study high grade tumour cells were least sensitive.