Effect of triptorelin (Decapeptyl) combined with heparin on estradiol levels in MCF-7 mammary cancer cells after incubation with estrone sulfate.

The effects of triptorelin (Decapeptyl) and heparin, alone or in combination, on the intracellular concentration of estradiol (E2) after incubation of estrone sulfate (E1S) with the MCF-7 mammary cancer cells was investigated. Although heparin (10 mg/l culture medium) or Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) did not affect the levels of radioactive E2 after incubation with [3H]E1S, the combination of Decapeptyl and heparin significantly decreased the radioactive uptake and the intracellular concentrations of [3H]E2. In the absence of Decapeptyl and heparin incubations with E1S, the resulting E2 concentration (in nmol/kg DNA +/- SD) was 558 +/- 44; after heparin (10 mg/l) plus Decapeptyl (5 x 10(-7) or 5 x 10(-5) mol/l) the values were 389 +/- 55 and 165 +/- 18, respectively. It is concluded that Decapeptyl with heparin can decrease very significantly the conversion of E1S to E2 in MCF-7 cells, an observation that suggests new possibilities for the control of E2 in hormone-dependent breast cancer.