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A 17,500-dalton protein which stimulates plasminogen activator production in cultured bovine capillary endothelial cells has been purified from a SK-Hep-l human hepatoma cell lysate by using heparin affinity chromatography and fast protein-liquid ion exchange chromatography. The purified molecule stimulated plasminogen activator production in a dose-dependent manner between 0.01 and 1 ng/ml. It also stimulated collagenase synthesis, DNA synthesis, and motility in capillary endothelial cells in the same concentration range. This molecule was identified as a basic fibroblast growth factor-like molecule on the basis of its biological activity, its affinity for heparin-Sepharose, and its cross-reactivity with a polyclonal antibody raised against the human placental basic fibroblast growth factor.

We have previously purified from human placenta a basic fibroblast growth factor (FGF)-like molecule which stimulates the production of plasminogen activator (PA) and collagenase, induces DNA synthesis, produces an increase in motility in cultured bovine capillary endothelial (BCE) cells, and induces angiogenesis in vivo. The ability of basic FGF to stimulate PA production in BCE cells was used as an assay for the presence of basic FGF-like molecules in extracts of both normal and tumor-derived cultured cells. The identity of the PA-stimulatory activity with basic FGF was confirmed by its high affinity for heparin and by its cross-reactivity with antibodies to human placental basic FGF. Basic FGF-like molecules were identified in eight of ten cell lines tested, and the amount of FGF-like activity present in these cells bore no relation to their origin from normal or tumor tissue. The test cells, BCE cells, had one of the highest levels of FGF-like activity, suggesting that it may have an autocrine role in these cells.

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