The PE represents the proliferation induced by the test substance in MCF-7 BUS cells.
The effects on the proliferation of MCF-7 BUS cells of E2 and nemorosone are shown in Table 1.
MCF-7 BUS cells were treated with benzophenone for 6 days, and cell growth was measured by the SRB method [ 27].
The growth of MCF-7 BUS cells was performed in order to ascertain the function of nemorosone as an estrogen agonists or as an estrogen antagonists.
The differences between estrogen-supplemented and nonsupplemented MCF7 BUS cells were due mostly to G0/G1 proliferative arrest mediated by charcoal dextran-stripped serum.
Of all the MCF7 stocks tested, MCF7 BUS cells showed the highest proliferative response to estradiol-17 beta: cell yields increased up to sixfold over those of nontreated cells in a 144-hr period.
In the absence of estrogen, MCF7 BUS cells stopped proliferating and accumulated in the G0/G1 phase of the cell cycle; estrogen receptors increased, progesterone receptors decreased, and small amounts of pS2 protein were secreted.
Subconfluent MCF-7 BUS cells were trypsinized and seeded in 24-well plates at an initial density of 2 × 10 cells per well in DMEM with 10% (v/v) FCS (1 mL/well).
In order to determine whether the nemorosone induced antiestrogenic activity, MCF-7 BUS cells were treated with a combination of E2 (10-8M) and the test compound at various concentrations, as shown in Figure 3.
The first step to evaluate the estrogenic activity of nemorosone by the E-screen assay was to construct the dose-proliferative response curve for E2 in MCF-7 BUS cells, and use it as a reference curve.
