CT26 cell line spheroids characterization.

<p><b>(A)</b> Radial profile of spheroid’s GFP fluorescence over 72 hours of invasion into collagen type I. Different zones of the spheroid can be distinguished: dark area, previously described as necrotic core (dotted line), proliferative rim (dashed line) and invasion (line and shaded area). Insert: representative image of spheroid (GFP) 24 hours post-seeding. Scale bar: 100 μm. <b>(B)</b> Morphology change over time of different-sized spheroids seeded into in collagen type I. Spheroids were imaged in bright field and fluorescence (GFP). Scale bar: 200 μm. <b>(C)</b> Growth kinetics of spheroids for three different initial sizes (<300 μm, 350–400 μm and >400 μm). Values are mean ± standard deviation of n = 6–12 from three independent experiments.