EFFECT OF DECAPEPTYL(R) (A GNRH ANALOG) AND OF TRANSFORMING GROWTH-FACTOR-ALPHA (TGF-ALPHA), IN THE PRESENCE OF HEPARIN, ON THE SULFATASE ACTIVITY OF HUMAN BREAST-CANCER CELLS

The effects of the polypeptide Decapeptyl(R) (a gonadotropin-releasing hormone (GnRH) agonist analogue) and of transforming growth factor-alpha (TGF-alpha), on estrone sulfate-sulfatase activities in the homogenates of various breast cancer cell lines were studied in the presence of heparin. In hormone-dependent MCF-7 breast cancer cells, Decapeptyl(R) can inhibit sulfatase activity, and this effect is significantly augmented in the presence of heparin. In the other hormone-dependent T-47D breast cancer cell line, the decrease of sulfatase activity was only significant when Decapeptyl(R) was associated with heparin. No significant effect on sulfatase activity elicited by heparin, Decapeptyl(R) or a mixture of both was found in the hormone-independent MDA-MB-231 breast cancer cells. TGF-alpha stimulates sulfatase activity in the MDA-MB-231 cells but has no effect in the MCF-7 cells; in contrast, TGF-alpha combined with heparin provokes a decrease of the sulfatase activity in both cell lines. It is concluded that the sulfatase activity in some types of breast cancer cell can be inhibited by heparin combined with the polypeptides Decapeptyl(R) or TGF-alpha.