Interleukin-1 as an Autocrine Stimulator in the Growth of Human Ovarian Cancer Cells

The role of interleukin-1 (IL-1), a multifunctional cytokine which mediates important immune responses, was investigated in the growth of ovarian cancer cell lines in vitro. The messenger RNA for IL-1α and IL-1β was expressed in six and four ovarian cancer cell lines, respectively out of eight. Measurement of IL-1 in the eight cell lines by enzyme-linked immunosorbent assay revealed that two lines, MCAS and TYK-nu, secreted a high amount of IL-1α, but that none secreted IL-1βafter 72 hours of incubation. The growth of these cells was significantly stimulated by the addition of recombinant IL-1α(rIL-1α) in a concentration-dependent manner in a 96 hour culture. The maximum response was obtained with 10 ng/ml of IL-1αby counting the viable cell number using trypan blue. [3H]-thymidine incorporation by these cells was also stimulated by a 72 hour incubation with rIL-1α. The spontaneous growth of these cells was inhibited by the addition of anti-IL-1αantibody, anti-IL-1 receptor antibody or IL-1 receptor antagonist. These cells expressed two classes of IL-1-binding receptors on their surface as detected by [125I]-labeled rIL-1α. These results indicate that IL-1αis an autocrine growth stimulator for some ovarian cancer cells and suggest that IL-1αplays an important role in the progression of this disease.