Sorafenib or B-Raf knockdown specifically reduces β1 and α4β1 integrin association with the cytoskeleton.
A, cytoskeletal stabilization assay of Jurkat cells incubated for 1 h with sorafenib (50 nm) and methanol vehicle control and then incubated with AF-488-conjugated anti-β1 integrin mAb and either cross-linked with an anti-mouse secondary mAb (×) or left untreated (NT) at 4 or 37 °C. B, cytoskeletal stabilization assay of vector control (VC) or B-Raf knockdown (KD) cells incubated for 1 h with sorafenib (50 nm) and methanol vehicle control and then incubated with AF-488-conjugated anti-β1 integrin mAb and anti-mouse secondary mAb at 4 or 37 °C. C, Cytoskeletal stabilization assay of Jurkat cells incubated for 1 h with sorafenib (50 nm) and methanol vehicle control and then incubated with AF-647-conjugated anti-mouse secondary mAb and either anti-α4β1 (19H8), anti-LFA-1 (32E6), anti-CD3, or anti-CD28 mAb at 4 or 37 °C. The percentage of Nonidet P-40-resistant mAb was determined by dividing the mean fluorescence intensity of Nonidet P-40-treated cells by the MFI of cells that received no Nonidet P-40. Error bars, S.E. *, p < 0.001 using Student's t test.