HGF-SF stimulation induces a functional response in c-met–expressing cells. (A) Northern hybridization analysis for c-fos expression in the myeloblastic cell line K562 after stimulation with 30 ng/mL recombinant HGF-SF. Hybridization for GAPDH is shown below. (B) Incubation of freshly isolated LPS/PHA prestimulated monocytes with recombinant HGF-SF. Bars represent mean of three independent experiments each measured in triplicate, with standard deviations and controls for each experiment indicated (PHA/LPS-stimulated monocytes adjusted to a relative value of 1). All values were determined by colorimetric assay (Biomedica; see Materials and Methods).