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

Abstract

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 alpha (IFN-alpha) and gamma (IFN-gamma), granulocyte-macrophage colony-stimulating factor (GM-CSF), tumour necrosis factor alpha (TNF-alpha), and transforming growth factor beta1 (TGF-beta1) were investigated by (125)I-deoxyuridine ((125)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 48h in culture, TGF-beta1, TNF-alpha, IFN-alpha and IL-6 showed a clear inhibitory effect on (125)IUdR incorporation (P<0.005), and IFN-gamma and GM-CSF caused even more significant inhibition (P<0.001). IFN-alpha and IFN-gamma were both growth inhibitory after 72h in culture (P<0.005). Similarly, GM-CSF induced a slight inhibition (P<0.05), whereas TGF-beta1 and TNF-alpha almost blocked DNA synthesis (P<0.001) after 72h. IL-6 had no statistically significant effect on cell proliferation after 72h. Transcription factors AP-1 and NF-kappaB 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-beta1 and TNF-alpha, and the binding of NF-kappaB was stimulated by TNF-alpha. Apoptosis does not seem to be induced by any of these cytokines in the UT-OC-3 ovarian cancer cell model.