Secretion and dual regulation between epidermal growth factor and transforming growth factor-beta(1) in MDA-MB-231 cell line in 42-hour-long cultures

MDA-MB-231 is a breast cancer cell Line which possesses large quantities of epidermal growth factor (EGF) receptors and specific high-affinity transfo rming growth factor-beta(1) (TGF-beta(1)) receptors. We have established th at these cells secrete constitutively measurable levels of EGF and TGF-beta (1) in conditioned medium. The constitutive secretion of EGF decreased over time in culture (42 h), while the constitutive secretion of TGF-beta(1) re mained constant. TGF-beta(1) secretion in EGF-treated cells was lower than in controls (P < 0.0001), but EGF concentrations were not modified after TG F-beta(1) supplement. We postulate that in MDA-MB-231 cell Line there is a dual regulation between both growth factors. (C) 1999 Elsevier Science irel and Ltd. All rights reserved.