A novel study on the effect of acetylsalicylic acid on the binding capacity of estrogen receptors from MCF-7 cells.

The effect of acetylsalicylic acid (ASA, aspirin) was investigated on [3H]-estradiol-17 beta ([3H]-E2) binding to estrogen receptors (ER) from MCF-7 mammary tumour cells. No effect was observed using the monoclonal estrogen receptor-enzyme immunoassay (ER-EIA). In contrast to the ER-EIA, the radioreceptor assay (RRA) showed decreases of [3H]-E2 specific binding in the presence of increasing amounts of ASA. It is therefore concluded that these results demonstrate that ASA possibly affects the direct binding of E2 to region E of the ER of human breast cancer MCF-7 cells, but does not affect binding of monoclonal antibodies to regions D and F of the ER.