Interleukin-6 (IL-6) production and cell growth of cultured human ameningiomas:- Interactions with interleukin-1β (IL-1β) and interleukin-4 (IL-4) in vitro

We examined the production of interleukin (IL)-6 by human meningioma cells in vitro, and the effects of IL-1β and IL-4 on IL-6 production and meningioma cell growth. The histological classification of the tumours studied included transitional, syncytial, fibroblastic and atypical. All 10 meningiomas studied produced IL-6 (range 0.22-7.6ng/ml/10⁶ cells/24 h). Separate addition of IL-1β or IL-4 to cultures increased IL-6 production up to ten fold, and two to three fold, respectively. Growth studies with IL-6 indicated that this cytokine significantly increased terminal cell density at a concentration greater than 1 ng/ml in 60% of the meningioma cultures studied. IL-1β caused a significant decrease in the terminal cell density in 25% of the meningioma cultures studied whereas IL-4 had a tendency to significantly inhibit growth in 16.6% of the cultures. These data suggest that IL-6 production by meningiomas can be modified by other cytokines and secondly, that IL-6, IL-1β and IL-4 can modify growth in vitro and may act as autocrine factors in vivo. By further determining the cytokine profiles within meningiomas and their effects, a better understanding of meningioma growth characteristics may be obtained.