Zeit- und konzentrationsabhängige Modulation der VEGF-Genexpression und der VEGF-Proteinmenge durch TNF[alpha] IL-1[beta], IL-6, EGF und TGF-[beta]1 in Ovarialkarzinomzellinien

Angiogenesis is essential for tumorgenesis. VEGF (vascular endothelial growth factor) as a potent angiogenic factor is of great importance for the development, progression and metastastasis of ovarian carcinoma. So far the regulation of VEGF in the microenvironment of ovarian cancer cell lines has been little investigated. This study examines the time- and concentration- dependent influence of the cytokines and growth factors TNF-alpha, IL-1beta, IL-6, EGF and TGF- beta 1 in regards to the VEGF- expression of the ovarian cancer cell lines BG-1, HEY and SKOV-3 by northern- analysis and ELISA. The stimulation with cytokines and growth factors resulted in minimal or not detectable increase of VEGF- gene- transcription. The cell line BG-1 shows VEGF- mRNA- accumulation that was time- dependent after stimulation with TNF- alpha, time- and concentration- dependent after treatment with IL-1 beta. The raise of VEGF- mRNA- transcripts of the cell line HEY was time- dependent after stimulation with TGF-beta 1 and unspecific after treatment with TNF- alpha. An enhanced transcription of the VEGF- gene was seen time- dependently after treating the cell line SKOV-3 with TNF- alpha, time- and concentration- dependently after stimulation with IL-1 beta, IL-6 and TGF- beta 1. An increase of VEGF- protein- concentration was detected in the cell culture medium of BG-1, HEY and SKOV-3 after application of any of the cytokines. Regarding the cell line BG-1 TNF- alpha, IL-6 and TGF- beta 1 had a time- and concentration- dependent effect. The application of EGF had a time- dependent effect only and stimulation with IL-1 beta did not show clear tendencies. The stimulation of the cell line HEY with IL-1 beta, IL-6 and TGF- beta 1 resulted in a time- and concentration- dependent increase of the VEGF- protein- secretion. The incubation with TNF- alpha and EGF had time- dependent effects only. TNF- alpha, IL-1 beta, IL-6 and EGF induced a time- dependent rise of VEGF- protein- concentration in the cell- line SKOV. Application of TGF- beta 1 had an additional concentration- dependent effect. The results on mRNA- and protein- level appear to be independent. Possibly the cytokines and growth factors act stronger on post- transcriptional mechanisms of VEGF- expression than on VEGF- gene- transcription and should therefore be characterized as indirect angiogenic factors. Assumingly their control and regulation in the microenvironment of ovarian carcinoma can be suspected to be of essential importance in terms of angiogenesis especially regarding the development, progression and metastasis of tumours as well as treatment