EXPERIMENTAL STUDY Regulation of UT-OC-3 ovarian carcinoma cells by cytokines: inhibitory effects on cell proliferation and activation of transcription factors AP-1 and NF-kB

The present study was designed to investigate the growth regulatory effects of cytokines in UT-OC-3 ovarian cystadenocarcinoma cells in vitro. The effects of interleukin-6 (IL-6), interferons a (IFN-a) and g (IFN-g), granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor a (TNF-a), and transforming growth factor b1 (TGF-b1) were investigated by I-deoxyuridine (IUdR) incorporation assay. In order to understand better the molecular mechanisms of the observed effects, the activation of DNA-binding proteins was studied by electrophoretic mobility shift assay. In addition, cellular DNA was tested by fragmentation analysis to determine if the most growth inhibitory cytokines are able to induce programmed cell death (apoptosis). After 48 h in culture, TGF-b1, TNF-a, IFN-a and IL-6 showed a clear inhibitory effect on IUdR incorporation (P<0.005), and IFN-g and GM-CSF caused even more significant inhibition (P < 0.001). IFN-a and IFN-g were both growth inhibitory after 72 h in culture (P < 0.005). Similarly, GM-CSF induced a slight inhibition (P < 0.05), whereas TGF-b1 and TNF-a almost blocked DNA synthesis (P < 0.001) after 72 h. IL-6 had no statistically significant effect on cell proliferation after 72 h. Transcription factors AP-1 and NF-kB were both constitutively expressed in UT-OC-3 cells. The binding activity of AP-1 was found to be stimulated by the growth inhibitory cytokines, TGF-b1 and TNF-a, and the binding of NF-kB was stimulated by TNF-a. Apoptosis does not seem to be induced by any of these cytokines in the UT-OC-3 ovarian cancer cell model. European Journal of Endocrinology 142 393–401