Synergistic interaction of growth factors and albumin in regulating estradiol synthesis in breast cancer cells

Abstract Estradiol 17β-hydroxysteroid dehydrogenase acts to convert estrone to the biologically active estrogen, estradiol, in breast tumors and MCF-7 breast cancer cells in vitro. In this study we have examined the ability of albumin to influence the effect of growth factors (insulin-like growth factor-I (IGF-I), epidermal growth factor (EGF), transforming growth factor-α (TGFα) and cytokines (interleukin (IL)-1, IL-6) on estradiol 17β-hydroxysteroid dehydrogenase activity in MCF-7 cells. IGF-I (80 ng/ml) or albumin (30 μg/ml) stimulated estradiol 17β-hydroxysteroid dehydrogenase activity by 144% and 102% ( p 125 I-albumin and binding is increased by pretreatment of cells with IGF-I (80 ng/ml) for 48 h. It is concluded that the synergism that results from treating MCF-7 cells with albumin and IGF-I may result from increased albumin uptake and subsequent biological effect.