Production and utilization of growth factors related to fibroblast growth factor by embryonal carcinoma cells and their differentiated cells

Previous studies have established that embryonal carcinoma (EC) cells produce several different growth factors, but express few, if any, receptors for epidermal growth factor, platelet-derived growth factor, or transforming growth factor type-beta. In this study, the production and utilization of fibroblast growth factor (FGF) by EC cells and their differentiated cells were investigated. We have determined that EC cells produce a heat-labile, heparin-binding factor that competes with FGF for binding to membrane receptors and appears to be immunologically related to FGF. The same or a similar factor is produced by three different EC cell lines, including a multipotent human EC cell line. However, production of this factor is apparently reduced when each EC cell line differentiates. Unlike the parental EC cells, the differentiated cells respond to FGF by growth stimulation and the growth responses to FGF correlate with increased binding of FGF. Although the binding data indicate that both the EC cells and their differentiated cells exhibit high affinity receptors for FGF, the differentiated cells express these receptors at levels approximately 10-fold higher. These findings suggest that the FGF-related growth factor could influence the growth of EC cells or their differentiated cells.