抄録
MCF-7 human breast cancer cells possess both aromatase activity and estrogen receptors. In this study, we examined how transforming growth factor-α (TGF-α) and insulin-like growth factor-I (IGF-I) influenced cell proliferation through the action of aromatase in MCF-7 cells.
We discovered that TGF-α suppressed the aromatase activity in MCF-7 cells and that IGF-I enhanced the activity. Both TGF-α and IGF-I stimulated [3H] thymidine incorporation into these cells. Estradiol-17β (E2) or testosterone (T)-generally after being converted to estrogen by aromatase-stimulated both [3H] thymidine incorporation and IGF-I production in MCF-7 cells when compared to the untreated cells by E2 or T. However, IGF-I, like TGF-α, reduced the stimulation of [3H] thymidine incorporation by E2 or T when either was added to the cell culture, suggesting that IGF-I interferes with estrogen-dependent proliferation.
This result may also suggest the presence of an autoregulatory system between estrogen-dependent and estrogen-independent proliferation channels in MCF-7.
