FIGURE 6.

Sam68-deficient HeLa cells have impaired EGF-induced cell migration. A, HeLa cells stably transfected with pSUPER (Ctrl shRNA) or Sam68 shRNA were examined for their ability to migrate toward PMA and human EGF (hEGF) using a Transwell migration assay. The cells that migrated are shown using crystal violet staining. The quantification is indicated on the right, and the migrating cells were normalized to the number of untreated HeLa Ctrl shRNA (counted in four random experiments) that migrated to the lower chamber. (*, p value ≤0.005) B, the expression of Sam68, β-actin, and the tyrosine phosphorylation of the EGF receptor (EGFR) in pSUPER control and Sam68sh HeLa cells was assessed by immunoblotting with anti-Sam68, anti-β-actin, and anti-phosphotyrosine (4G10) antibodies. C, shown is the Sam68 expression level in HeLa Sam68 shRNA cells versus pSuper control cells. In addition, HeLa cells were treated with an siGENOME siRNA that targets Sam68 or a control siRNA. The level of Sam68 expression was assessed by immunoblotting (WB) with anti-Sam68 and compared with the level of β-actin. D, pSUPER and Sam68sh HeLa cells were plated on fibronectin-coated tissue culture dishes, and a wound was introduced. The directional migration of the cells was visualized by crystal violet staining. E, HeLa cells were transfected with siGENOME Sam68 siRNA or control small interfering GFP. The directional migration of the cells was visualized by crystal violet staining.