Alpha-fetoprotein receptors in a human breast cancer cell line.
Evidence is presented for the existence of specific receptors for alpha-fetoprotein on the surface of MCF-7 human breast cancer cells. At 4 degrees C, the binding of alpha-fetoprotein to these cells displayed a biphasic saturation curve. Scatchard analysis revealed the presence of at least two binding sites with dissociation constants of 4.5 X 10(-9) M (2,000 sites/cell) and 1.3 X 10(-8) M (135,000 sites/cell), respectively. Binding was inhibited by 85% in the presence of a 5,000-fold excess of unlabeled alpha-fetoprotein and by 50% with the same excess of serum albumin. Competition by other serum proteins was not significant. At 37 degrees C, alpha-fetoprotein was endocytosed and the uptake curve reached a plateau after 3-4 hours of incubation.
D001667:Binding, Competitive; D001943:Breast Neoplasms / Q000378:metabolism*; D002460:Cell Line; D005260:Female; D006801:Humans; D007700:Kinetics; D011956:Receptors, Cell Surface / Q000302:isolation & purification* / Q000378:metabolism; D018000:Receptors, Peptide; D000509:alpha-Fetoproteins / Q000378:metabolism*
D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; D000509:alpha-Fetoproteins; C042144:alpha-fetoprotein receptor, human