Fig. 3: Crizotinib inhibits in vitro TβRI kinase activity.

NCI-H3122 (a) and A549 (b) cells were pretreated with TGFβ (1 ng/mL) for 30 min, washed, and further incubated with or without crizotinib (10 μM) in the presence of SB431542 (10 μM) for the indicated times prior to western blot analysis. c The in vitro kinase activity of TβRI was measured in the presence of crizotinib or SB431542 (serially diluted in fourfold increments from 0.000153 to 10 μM) and expressed as luminescence signal values (relative light unit, RLU). The data were expressed as the mean ± SEM (n = 4). d Lineweaver–Burk plot analysis of 1/ν versus 1/[S]. The in vitro kinase activity of TβRI was measured at various concentrations of ATP (25, 50, 100, 200, 400, and 800 μM) in the presence of crizotinib (1 or 10 μM). The data were expressed as the mean ± SEM (n = 4). S, ATP. e Each indicated inhibitor at 10 μM was added to the enzyme reaction mixtures. The in vitro kinase activity of TβRI was expressed as luminescence signal values. The data were expressed as the mean ± SEM (n = 4). ***p < 0.005. f NCI-H3122, A549, and Calu-1 cells were treated with TGFβ (1 ng/mL), crizotinib (10 μM), or both for 30 min or 24 h prior to western blot analysis.