PDF file - 74K, Effective inhibition of c-Met phosphorylation in U87MG cells. To assess the pharmacodynamic activity of EMD 1214063 and EMD 1204831 in glioblastoma, U87MG glioblastoma cells were exposed for 2 h to either EMD compound. After lysis, the phosphorylation levels of c-Met Y1234/Y1235 auto-phosphorylation site (A) and of c-Met Y1349 adaptor binding site (B) were assessed and correlated with the levels of total c-Met by a Luminex-based assay. Y1234/Y1235 EC50 values for EMD 1214063 and EMD 1204831 were 0.003 �M and 0.009 �M, respectively. For Y1349, the EC50 values were 0.011 �M and 0.005 �M for EMD 1214063 and EMD 1204831, respectively. While a dose-dependent reduction in the levels of c-Met phosphorylation could be observed upon exposure to both compounds, the levels of total c-Met remained unchanged (C). Data are cumulative of three independent experiments.
ARTICLE ABSTRACT
Purpose: The mesenchymal–epithelial transition factor (c-Met) receptor, also known as hepatocyte growth factor receptor (HGFR), controls morphogenesis, a process that is physiologically required for embryonic development and tissue repair. Aberrant c-Met activation is associated with a variety of human malignancies including cancers of the lung, kidney, stomach, liver, and brain. In this study, we investigated the properties of two novel compounds developed to selectively inhibit the c-Met receptor in antitumor therapeutic interventions.Experimental Design: The pharmacologic properties, c-Met inhibitory activity, and antitumor effects of EMD 1214063 and EMD 1204831 were investigated in vitro and in vivo, using human cancer cell lines and mouse xenograft models.Results: EMD 1214063 and EMD 1204831 selectively suppressed the c-Met receptor tyrosine kinase activity. Their inhibitory activity was potent [inhibitory 50% concentration (IC50), 3 nmol/L and 9 nmol/L, respectively] and highly selective, when compared with their effect on a panel of 242 human kinases. Both EMD 1214063 and EMD 1204831 inhibited c-Met phosphorylation and downstream signaling in a dose-dependent fashion, but differed in the duration of their inhibitory activity. In murine xenograft models, both compounds induced regression of human tumors, regardless of whether c-Met activation was HGF dependent or independent. Both drugs were well tolerated and induced no substantial weight loss after more than 3 weeks of treatment.Conclusions: Our results indicate selective c-Met inhibition by EMD 1214063 and EMD 1204831 and strongly support clinical testing of these compounds in the context of molecularly targeted anticancer strategies. Clin Cancer Res; 19(11); 2941–51. ©2013 AACR.
