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-al pha (TGF-alpha), on estrone sulfate-sulfatase activities in the homoge nates of various breast cancer cell lines were studied in the presence of heparin. In hormone-dependent MCF-7 breast cancer cells, Decapepty l(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 o nly significant when Decapeptyl(R) was associated with heparin. No sig nificant effect on sulfatase activity elicited by heparin, Decapeptyl( R) or a mixture of both was found in the hormone-independent MDA-MB-23 1 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, TG F-alpha combined with heparin provokes a decrease of the sulfatase act ivity in both cell lines. It is concluded that the sulfatase activity in some types of breast cancer cell can be inhibited by heparin combin ed with the polypeptides Decapeptyl(R) or TGF-alpha.