Real-time detection of insulin-like growth factor-1 stimulation of the MAC-T bovine mammary epithelial cell line.
Binding of growth factors by cell-surface receptors is an essential means by which cells regulate normal tissue growth and differentiation. Exposure to growth factors is often transient, and our goal was to determine whether short-term exposure to insulin-like growth factor-1 (IGF-1) would lead to activation, assayed as cell proliferation, of mammary epithelial cells. The MAC-T cell line is an immortalized bovine mammary epithelial cell line, chosen as our model mammary cell line because of its known sensitivity to IGF-1. Using the Cytosensor Microphysiometer System, a biosensor capable of measuring extracellular acidification, we were able to measure activation of the cells owing to IGF-1 addition in real time and found that peak acidification occurred in only 14 min. We show that this rapid response to IGF-1 is dose dependent and specific for IGF-1. A significant increase in [3H]thymidine incorporation by cells after a similar short-term exposure to IGF-1 suggests that the measured increase in extracellular acidification following IGF-1 addition is physiologically relevant. This technology offers a new, novel, and rapid means for the study of IGF-1 activity, as well as the screening of IGF-1 inhibitors, in mammary epithelial cells.
Robinson
R M
RM
Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
Akers
R M
RM
Forsten
K E
KE
D000818:Animals; D002417:Cattle; D002452:Cell Count; D002455:Cell Division; D002461:Cell Line, Transformed; D004247:DNA / Q000096:biosynthesis; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000494:pharmacology*; D007700:Kinetics; D008321:Mammary Glands, Animal / Q000166:cytology* / Q000378:metabolism; D013936:Thymidine / Q000378:metabolism; D014316:Tritium
D007328:Insulin; D014316:Tritium; D007334:Insulin-Like Growth Factor I; D004247:DNA; D013936:Thymidine