THE INHIBITORY EFFECT OF MEDROXYPROGESTERONE ACETATE ON STEROID SULFATASE IN HUMAN UTERINE ENDOMETRIAL CANCER-CELLS

The activity of estrone sulfatase (E(1)SF), which converts estrone sul fate to estrone, In uterine endometrial cancer tissue is remarkably hi gh compared with endometrial tissues, and this is assumed to contribut e to the growth of this tumor. Thus, in this study, in order to screen drugs for sulfatase inhibitor activity, the inhibitory effect of medr oxyprogesterone acetate (MPA; which is widely used for advanced or rec urrent endometrial cancer) on E(1)SF activity and steroid sulfatase (S TS) gene expression in endometrial cancer cells was examined and compa red with danazol (DZ). MPA and DZ were shown to inhibit E(1)SF activit y dose-dependently in the established endometrial cancer cell lines (I shikawa and HEC-59 strains). These drugs (10(-8) M) also inhibited the expression of STS mRNA, and this inhibition of STS gene expression is considered to partly explain their inhibitory actions against STS.