Effect of Rac3 inhibition on cell morphology, migration, adhesion and invasion. MDA-MB-231, MCF-7 and MCF-10A cells were treated during 48 h with 10 nM siRNA (control or Rac3). (A) Cells were fixed and (A1) cell morphology was observed; (A2) and labelled with phalloidin-TRITC to visualize the actin cytoskeleton (scale bar represents 50 μm). (B) Scratch test: wound closure was observed by microcinematography for 48 h; extent of closure at indicated times is expressed as % of initial scratch width. (C) Adhesion of MDA-MB-231 to collagen type I matrix under flow conditions. Attached cells were counted and their numbers expressed as % of control. (D) Invaded MDA-MB-231 in Boyden chambers were counted and expressed as % of control. (E) 48 h conditioned media from siRNA-treated cells (center and right lanes; ladder, left lane) was collected and MMPs present in this medium were detected by zymography; quantification on the right. Mean ± S.E., N=3 independent experiments. *P<0.05; ** P<0.01; ***P<0.001.