Fig. 2.

Substratum stiffening reduces the EGF threshold needed to transition from contact-inhibited to contact-independent proliferation. MCF-10A cells plated on soft (7 kPa) and stiff (31 kPa) substrates coated with fibronectin were serum starved and stimulated with the indicated doses of EGF or left untreated. (A) BrdU uptake (green) and DAPI staining (blue) were assessed 22 hours after EGF treatment. (B) The fractions of interior and peripheral cells incorporating BrdU were quantified, and the ratio of these two fractions is plotted as a function of EGF concentration. Values are mean ± s.d. (n=2–3), ANOVA followed by post-hoc tests *^,**P<0.05. Scale bar: 100 μm.