Enhancement of anchorage‐independent growth of a human adrenal carcinoma cell line by endogenously produced basic fibroblast growth factor

We have previously observed that a human adrenal carcinoma cell line (SW-13) produces autocrine growth factors that enhance the ability of these cells to clone in soft agar. We now show that a basic FGF-like protein is found in SW-13 lysates and stimulates SW-13 colony growth. Basic FGF (bFGF) was identified in SW-13 lysates by both its chromatographic behavior on heparin-Sepharose and its reactivity with an antibody specific for bFGF. Incubation of lysates with antibodies specific for bFGF abolished their ability to support anchorage-independent growth. Northern analysis demonstrated that the cells produced multiple bFGF mRNA transcripts. SW-13 cells also expressed bFGF cell-surface receptors. These data suggest that SW-13 cells produce and respond to a factor structurally and functionally related to bFGF. Such findings support recent evidence indicating that FGF secreted by human tumor cell lines plays a role in the maintenance of the transformed phenotype.