An uncleavable form of pro–scatter factor suppresses tumor growth and dissemination in mice
J. Clin. Invest. Massimiliano Mazzone, et al. 114:1418 doi:10.1172/JCI22235 [
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Figure 4Uncleavable SF inhibits the pleiotropic activities of SF on living cells. (
A) End-point scatter assay. A549 cells transduced with the indicated lentivirus vector were stimulated with progressive 1:2 dilutions of active SF starting from 64 ng/ml. The minimal concentration at which scattering was observed is indicated (scatter threshold [ST]). Representative images show crystal violet–stained cells at 8 ng/ml (the concentration of active SF). (
B) Survival assay. Lentivirus vector–transduced MDA-MB-435 cells were pre-incubated with either recombinant SF (+SF) or no factor (–SF) and then were cultured in the absence (No drug) or presence (Staurosporine) of staurosporine. (
C) Mitogenic assay. Lentivirus vector–transduced A549 cells were stimulated with either recombinant SF or no factor, and DNA synthesis was assessed by [
3H]thymidine incorporation. (
D) Matrigel invasion assay. MDA-MB-435-β4 cells were analyzed for their ability to invade a Matrigel layer in the presence or absence of recombinant SF. (
E) Collagen invasion assay. Lentivirus vector–transduced MDA-MB-435 cells were examined for their ability to form branched, multicellular tubules in response to SF stimulation. (
F) Representative images from the experiment described in
E. Statistical significance (*
P < 0.05; **
P < 0.01) refers to the difference between –SF and +SF.
