[Growth promoting effect of IL-6 on medulloblastoma cells in vitro]

Expression of IL-6 and IL-6 signal transducer genes (IL-6R and gp130) in human medulloblastoma cells were investigated by Northern blot analysis, RT/PCR and immunocytochemical staining. The results revealed that among 13 tumor cases and 3 established medulloblastoma cell lines, 95% of them were found to express full set of IL-6 signal transducer genes, IL-6R and gp 130, but none of them expressed IL-6. Incubation of medulloblastoma cells in vitro with recombinant IL-6 could apparently stimulate cell growth and enhance DNA synthesis. Our data thus for the first time demonstrate that though IL-6 is not expressed by medulloblastoma cells themselves, IL-6 can act on medulloblastoma cells through its signal transducers by a paracrine pathway. Since medulloblastomas are surrounded by gliosis and infiltrated by immune activated cells which are known to express IL-6, the influence of those IL-6 producing cells on the development and progression of medulloblastomas should be taken into account.