CHARACTERIZATION AND PARTIAL-PURIFICATION OF HUMAN EPITHELIAL TRANSFORMING GROWTH-FACTOR

A polypeptide growth factor has been partially purified from medium conditioned by the human adrenocortical carcinoma cell line SW13. This factor, designated h‐TGFe, stimulates anchorage‐independent growth of the SW13 cells. Similar activity was observed in human milk, and in conditioned media from seven of 14 epithelial cell lines. The SW13‐derived activity is stable to low pH and 8M urea but labile to dithiothreitol and 2% sodium dodecyl sulfate. Human TGFe does not bind to heparin and fails to stimulate growth of endothelial cells in monolayer culture. The apparent molecular weight of h‐TGFe is 59k by size exclusion chromatography in the presence of 8M urea and the activity binds strongly to cation exchangers. The activity elutes at 15–30% acetonitrile from a C18 reversephase column and has been partially purified by using a four‐step chromatographic procedure. TGFe appears to be a novel growth factor produced by many epithelial cells and tissues. Copyright © 1990 Wiley‐Liss, Inc.