Introduction: Phytoestrogens are a diverse group of nonsteroidal plant compounds that occur naturally in many plants. Because they possess a ring system similar to estrogens they are able to bind to estrogen receptors in humans. With this study we tested the effects of the phytoestrogens genistein and daidzein in cell proliferation and the production of progesterone and hCG in trophoblast tumour cells of the cell lines BeWo and Jeg3.
Materials and methods: The phytoestrogens genistein and daidzein were incubated in different concentrations with trophoblast tumour cells. Untreated cells were used as controls. At designated times, aliquots were removed and tested for progesterone and hCG. In addition we tested the effects of phytoestrogens on cell proliferation. Different concentrations of genistein and daidzein were cultivated with trophoblast tumour cells. After designated times, 1 microCi thymidin-(methyl-3H) was added. Methyl-3H thymidin incorporation was tested and compared to incorporation results of untreated cells.
Results: With this study we could show that the production of the steroid hormone progesterone and the protein hormone hCG is influenced by the phytoestrogens genistein and daidzein in trophoblast tumour cells of the cell lines BeWo and Jeg3. We found a correlation between the effects on the proliferation and the production of progesterone and hCG at high concentrations of genistein and daidzein in the cell lines tested. With low concentrations of genistein and daidzein we observed a stimulation of the production of hCG and a weak inhibition of proliferation in both cell lines BeWo and Jeg3.
Discussion: The results obtained with this study suggest that only high doses of phytoestrogens (> 1 mumol/ml) can reduce the proliferation of trophoblast tumour cells significantly. Low doses of phytoestrogens induced a higher hCG production in both cell lines tested. Although high hCG production did not lead to a higher proliferation rate of the tumour cells tested, hCG is able to induce neovascularisation in tumour cells. In summary, with this in vitro study we showed that high doses of phytoestrogens inhibit proliferation and progesterone production in trophoblast tumour cells. High doses of phytoestrogens could be useful candidates for special diet programs for prevention and surgery for patients with this type of disease. In addition we found a useful cell culture model for the testing of new types of phytoestrogens.