Production of somatomedin-like activity by human adult tumor-derived, transformed, and normal cell cultures and by cultured rat hepatocytes: effects of culture conditions and of epidermal growth factor (urogastrone)

Abstract

We have measured the production of a basic-somatomedin-like activity (SLA) by a variety of human tumor-derived, transformed, and normal postnatal cell cultures; and we have compared the production of SLA by these cell types with the production of SLA by adult rat hepatocytes cultured in serum-free medium. Cells derived from a human epidermoid carcinoma (KB), a pancreatic carcinoma (Panc-1), a Simian virus 40 transformed adult human skin-derived cell line (SV₄₀ fibroblasts), and a normal adult human skin-derived fibroblast line released SLA when cultured in a serum-free growth medium. No SLA was recovered from the culture medium of human choriocarcinoma-derived cells (BeWo) or of a human lymphoblastoid cell line (IM-9). The production of SLA by rat hepatocytes cultured in serum-free medium appeared to exceed the production of SLA by the other cell cultures. In cultures of KB cells, SV₄₀ fibroblasts, and rat hepatocytes, the production of SLA depended on the frequency with which the growth medium was renewed; in general, the highest rates of SLA production were observed when the medium was renewed every 48–72 h. The presence of mouse epidermal growth factor (urogastrone) (EGF-URO) in the serum-free culture medium stimulated the production of SLA by KB cells and by rat hepatocytes, but did not increase SLA production by normal or by SV₄₀-transfonned human skin-derived fibroblasts. We conclude that tumor-derived cells are capable of producing somatomedin-like activity and that the production of SLA by such cells can be subject to controls (nutrient availability, EGF-URO stimulation) that regulate SLA production, either by normal adult tissues, like liver, or by a variety of normal embryonic tissues.