title: Purification and characterization of an alpha 1-antichymotrypsin-like 66 kDa protein from the human breast cancer cell line, MCF-7.
abstract: The synthesis of a 66 kDa protein immunoreactive with antibodies to human alpha 1-antichymotrypsin (alpha 1-ACT) is induced by estradiol (E2) in the human breast cancer cell line MCF-7. We have purified this alpha 1-ACT-like 66 kDa protein from medium conditioned by MCF-7 cells, performed a comparative physico-chemical characterization with serum alpha 1-ACT, and analysed its presumed positive regulatory effect on growth of MCF-7 cells. The 66 kDa protein is a functional antiproteinase which is antigenically identical to serum alpha 1-ACT. The 66 kDa protein does however deviate from serum alpha 1-ACT with respect to mol. wt. and pattern of microheterogeneity, the molecular mechanism for this is probably an incomplete glycoprotein processing in the MCF-7 cells. The results of our growth experiments suggest that the 66 kDa protein is a minor positive growth regulatory factor, which may contribute to breast carcinoma cell proliferation in a cooperative manner.
authors.affiliation: Department of Tumor Endocrinology, Fibiger Institute, Danish Cancer Society, Copenhagen.
authors.forename: I
authors.initials: I
authors.lastname: Laursen
authors.forename: A E
authors.initials: AE
authors.lastname: Lykkesfeldt
mesh_terms: D000906:Antibodies; D001943:Breast Neoplasms; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D016895:Culture Media, Serum-Free; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006133:Growth Substances / Q000302:isolation & purification*; D006801:Humans; D007123:Immunoelectrophoresis, Two-Dimensional; D007525:Isoelectric Focusing; D008970:Molecular Weight; D000514:alpha 1-Antichymotrypsin / Q000096:biosynthesis / Q000302:isolation & purification* / Q000494:pharmacology
chemical_list: D000906:Antibodies; D016895:Culture Media, Serum-Free; D006133:Growth Substances; D000514:alpha 1-Antichymotrypsin; D004958:Estradiol