NIH3T3 cells stably expressing wild-type or Asp153Tyr mutant MET were plated in complete medium. After 24 h, the medium was replaced with serum-free medium and cells were treated with the indicated concentration of recombinant HGF (R&D Systems). Cell growth was measured after 3 d with the CellTiter-Glo luminescence cell viability kit (Promega) as described previously98 (link). Student's t test (two-tailed) was used for statistical analyses to compare treatment groups with GraphPad Prism 5.00. A P value of <0.05 was considered statistically significant (*P < 0.05 and **P < 0.01).