Direct antiproliferative effect of triptorelin on human breast cancer cells

We investigated the effect of Triptorelin (Decapeptyl, DEC) alone or combined with Tamoxifen (TAM) or Medroxyprogesterone acetate (MPA) in human breast cancer cells. DEC did not affect the growth of estrogen-insensitive MDA-MB-231 cells, while it inhibited the estrogen-stimulated proliferation of MCF-7 and CG-5 cells. No amplification of growth inhibition induced by TAM or MPA was determined by DEC. Progesterone receptor levels of CG-5 cells were significantly enhanced by DEC in the presence of 17 beta-estradiol (E2) with respect to those in control and E2-treated cells.