Response of MCF-7 human breast cancer cells to some binary mixtures of oestrogenic compounds in-vitro

The effects of simultaneous administration of some binary mixtures of seven natural and synthetic oestrogenic substances (17 beta -estradiol, estrone, bisphenol A, butylbenzyl phthalate, endosulfan, methoxychlor and pentachlo rophenol) on the cellular proliferation of human breast cancer MCF-7 cells in-vitro (a modified E-screen assay) have been measured. To assess the pres ence or absence of interactions of the two agents, the data were analysed o n the basis of a graphical method in which the types and extents of interac tions were described by response-surface diagrams. Of the nine combinations of the agents examined, synergistic interaction was evident for the combin ation of 17 beta -estradiol and bisphenol A, whereas the remaining eight co mbinations were weakly synergistic, additive and/or weakly antagonistic in the dose-range tested.