Figure 4.

MS275 activates GTP-RhoA, inducing reorganization of actin cytoskeleton in leukemia. (A) RhoA-GTP GST pull-down assay in U937 cells stimulated with MS275 (5 μM) in presence or absence of the exoenzyme C3 transferase (1 μg/mL) for the indicated times. GTP-bound RhoA was visualized by Western blot analysis. The results are representative of at least 2 independent experiments. (B) Left. Inverted black-and-white images of IF staining of cytoskeletal actin filaments with Texas Red-labeled phalloidin antibody in U937 cells upon MS275 treatment (5 μM) or exoenzyme C3 transferase (1 μg/mL) for the indicated times. Scale bar 10 μm. Right. Signal intensity quantification analyzed as the media of the intensities of different areas for each sample in the same acquisition region. Differential P value is < di 0,005.