title: Microphysiometry to evaluate real-time response of mammary epithelial cells to IGF-I.
abstract: The Cytosensor Microphysiometer, a biosensor developed by Molecular Devices, was used to assay rapid binding activity of IGF-I for bovine mammary epithelial cell lines. Insulin-like growth factor-I (IGF-I) is a potent mitogen for mammary epithelial cells and has been implicated in breast cancer cell proliferation, a leading cause of cancer death of women in the U.S. today. IGF-I acts by binding to cell surface receptors. We are interested in how autocrine secretion might alter the activity and regulation of IGF-I. Real-time changes in excretion of protons, which we assert results from IGF-I binding, are detected by the Cytosensor Microphysiometer and can be correlated with cellular activity. We present IGF-I dose-dependent responses as well as correlated binding data to detect cell surface receptor concentration and thymidine incorporation results to determine cell proliferation following IGF-I stimulation. We examine the effect of insulin-like binding protein-3 (IGFBP-3) both in the presence and absence of IGF-I. We believe comparison of autocrine and paracrine environments for IGF-I stimulation, and the components contributing to the binding of IGF-I to the cell membrane receptor may provide pertinent information for the development of intervention schemes to slow or interrupt IGF-I binding to tumor cells and therefore cancer growth.
authors.affiliation: Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Robinson
authors.forename: R M
authors.initials: RM
authors.lastname: Akers
authors.forename: K E
authors.initials: KE
authors.lastname: Forsten
mesh_terms: D000818:Animals; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006863:Hydrogen-Ion Concentration; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000187:drug effects / Q000378:metabolism* / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000378:metabolism* / Q000494:pharmacology*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008832:Microchemistry / Q000295:instrumentation / Q000379:methods*; D017526:Receptor, IGF Type 1 / Q000187:drug effects / Q000378:metabolism
chemical_list: D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1