Figure 3.

Measurement of inhibitory and antiproliferative activities of the novel C6-substituted androgens in purified aromatase and MCF-7a breast cancer cells. (a) SDS–PAGE analysis of a typical sample of purified human placental aromatase used for enzyme inhibition and complex crystallization experiments. (b) Enzyme inhibition activity of the novel inhibitors plotted as a function of concentration. Averaged data points and their standard deviations (SDs), resulting from quadruplicate measurements of three independent experiments, are shown for eight C6-substituted androgens (2–9) and three known inhibitors as controls. (c) Bar graphs representing E2-, ASD-, and TST-stimulated proliferation of MCF7a cells. The growth of MCF-7a cells is stimulated by 10 pM to 100 nM E2 and TST or by 1 nM to 100 nM ASD. The mean of three independent experiments and the SD are shown for each data point. (d) Inhibition of TST-induced proliferation of MCF-7a cells by the six most potent C6-substituted androgen inhibitors (4–9), as a function of concentration. The same symbol and color as (b) are used to designate each inhibitor. The data are normalized against the control cells treated with 1 nM TST alone. Each data point and the SD are the result of three independent experiments measured in triplicate.