Impact of the small molecule Met inhibitor BMS-777607 on the metastatic process in a rodent tumor model with constitutive c-Met activation

c-Met tyrosine kinase hyperactivation is strongly associated with tumor metastasis. In a prior study we showed that BMS-777607, a novel selective small molecule Met kinase inhibitor, potently suppressed ligand-mediated functions in prostate cancer cells. Herein we evaluated the impact of this agent on the potential of the highly metastatic murine KHT sarcoma that carries constitutive activated c-Met. MET gene knockdown was found to reduce spontaneous cell scatter and motility, suggesting a c-Met-dependent disseminating ability in KHT cells. Furthermore, BMS-777607 treatment potently inhibited KHT cell scatter, motility and invasion at doses in the nanomolar range. In contrast, cell proliferation and clonogenicity were modestly affected by BMS-777607. At the molecular level, BMS-777607 potently blocked phosphorylation of c-Met and downstream pathways over the same dose range that impacted metastasis-associated cell functions. In vivo, daily treatment with BMS-777607 (25 mg/kg/day) over the course of the study significantly decreased the number of KHT lung tumor nodules (28.3 +/- 14.9%, P<0.001) without apparent systemic toxicity. While treatment for short intervals (day 1 or 4) clearly reduced the foci number, delaying the initiation of BMS-777607 treatment until 8 days after tumor cell injection failed to show any reduction, implying that impairment of the initiation phases of the secondary growth via c-Met targeting is required to constrain the formation of macroscopic metastases. Together, the present findings demonstrate that the disruption of c-Met signaling by BMS-777607 significantly impairs the metastatic phenotype, suggesting that this agent may have therapeutic utility in targeting cancer metastasis.