[Structure and biological property of fibroblast-derived tumor cytotoxic factor (F-TCF)]

Fibroblast-derived tumor cytotoxic factor (F-TCF), isolated from human embryonic lung fibroblasts, is cytotoxic against various human and mouse tumor cells. Physicochemical and biological properties indicate that F-TCF is closely similar to hepatocyte growth factors (HGFs), cDNAs of which are isolated from human liver and placenta. Isolation and expression of F-TCF cDNA revealed that F-TCF was identical to the placenta type HGFs, including a variant with a deletion of 15 base pairs in the coding region. The deleted form of recombinant HGF (rHGF) had slightly lower heparin binding affinity than the intact form. Specific activities of rHGFs were almost the same in tumor cytotoxic activity, but different in hepatocyte growth stimulating activity. These results indicate that deletion of five amino acids results in conformational change which alter biological activity.