Correlation of Estrogen Sulfotransferase Activity and Proliferation in Normal and Carcinomatous Human Breast. A Hypothesis

Abstract

Background: Sulfotransferases are present in normal and cancerous human breast tissues. The purpose of this article is to present a hypothetical correlation of sulfotransferase activity with proliferation in breast cancer. Materials and Methods: Sulfotransferases were evaluated in breast cancer cells by determining the transformation of non-conjugated estrogens to the sulfates. Proliferation was evaluated by the action on cell growth or the size of a transplanted tumor. The effect was obtained using the progestins: nomegestrol acetate, promegestone, and medrogestone, as well as tibolone and its metabolites at concentrations of 5×10^-5 to 5×10^-9 M. Results: A possible correlation of sulfotransferase activity stimulation and cell growth inhibition provoked by the various progestins used, or by tibolone and its metabolites was shown. Conclusion: It is suggested that the antiproliferative effect of these compounds could be related to the decrease of bioactive estradiol by the formation of its biologically inactive sulfate as a consequence of the stimulatory effect by the various progestins or tibolone on sulfotransferase activity.