REDUCTION OF THE CALCIUM REQUIREMENT OF NORMAL HUMAN EPITHELIAL-CELLS BY EGF

The influence of epidermal growth factor (EGF) on the Ca2+ requirement of normal (NP-2s) and neoplastic human epithelial (PC-3) cells was studied using a clonal growth assay. The interaction of Ca2+ and EGF was investigated by kinetic analysis of dose-response experiments in which the Ca2+ or EGF concentration necessary for half-maximal growth, Km were determined. The normal epithelial cells required 80 times more calcium than did the cancer cells. In the presence of EGF, the Ca2+ requirement of both cell types was virtually identical. EGF did not affect the growth rate of the cancer line. The interaction between Ca2+and EGF was found to be unidirectional since EGF reduced the KmCa2+ 120-fold, whereas Ca2+ had no effect on the EGF dose-response. © 1979.