Syk Loss in Breast Cells Figure 2. siRNA knockdown of Syk increases motility and invasive cell morphology in three dimensional cultures. (A) Cells were transfected with control or Syk siRNA and cultured in Matrigel for 48 hours. MCF10A colony size was the most dramatically influenced by Syk knockdown. Scale bars correspond to 200 mm. (B) Cells were seeded at sub-confluent densities on top of bovine collagen I gels (3.0 mg/ml), cultured 5 or 20 hours, fixed and stained with AlexaFluor488-phalloidin. Images of cells cultured for 20 h are shown. Scale bars are 50 mm (at left) and 5 mm in the higher magnification views at right. The invasive phenotype was quantified by measuring shape factor. A shape factor of 1 is equivalent to a circle. (C) In a separate experiment, the velocity of cell migration on collagen I was determined. Scale bars are 10 mm. (A–C) P values are significant by the student’s t-test for all three cell lines. Data are represented as mean +/2 SEM. doi:10.1371/journal.pone.0007445.g002 PLoS ONE | www.plosone.org 4 October 2009 | Volume 4 | Issue 10 | e7445