DIRECT GROWTH-INHIBITION OF HUMAN ENDOMETRIAL CANCER-CELLS BY THE GONADOTROPIN-RELEASING-HORMONE ANTAGONIST SB-75 - ROLE OF APOPTOSIS

OBJECTIVE: Our objective was to study the direct action of the gonadot ropin-releasing hormone antagonist SB-75 and the agonist buserelin on the proliferation of endometrial cancer cells. STUDY DESIGN: Two human endometrial cell lines that differ in histologic subtype and estrogen receptor content were treated with gonadotropin-releasing hormone ana log. We measured the number of viable cells, cell cycle parameters, an d apoptotic processes. RESULTS: Growth of the Ishikawa cells was inhib ited by SB-75 in a dose-dependent manner. 17 beta-Estradiol partially abolished the inhibitory effect of SB-75. The growth of the HEC-1A cel ls was not affected by the antagonist. Neither endometrial cancer cell line showed significant sensitivity to the agonist buserelin. Tenfold concentration of the gonadotropin-releasing hormone agonist did not a bolish the inhibitory effect of the antagonist on cell growth. The gro wth inhibition was not associated with any change in cell cycle parame ters but was associated with an induction of apoptosis. CONCLUSION: Th e gonadotropin-releasing hormone antagonist SB-75 directly inhibits th e growth of some human endometrial cancer cells and thus may be suitab le for the treatment of endometrial tumors.