S1. Sprouting Quantification Methodology
Analysis for Vessel Quantification: We have developed an in-house
algorithm for quantifying angiogenesis in the platform. We map the
experimental vessel that is a cylinder with a near elliptical cross
section onto a true cylinder. This is reasonable since a
~ 0.95b, where a is the semi-major axis and b is the
semi-minor axis of the elliptical cross section. We then map the
elliptical cross section onto a circular cross section and assume this
preserves area since a is nearly equal to b. Since the true cylindrical
vessel has radius R and we are interested in quantifying vascular
sprouting at distances of 50, 100, 150, etc. from the vessel, we create
cylindrical shells that are 50, 100, 150, etc. microns from the
experimental vessel. We construct this surface using intensity values of
fluorescence and unroll the cylindrical shells into rectangular
surfaces. We use an intensity threshold on these surfaces and then
quantify vessel sprouting by taking area thresholds of varying size that
correspond to the cross-sectional area of the vessel going through these
constructed surfaces at varying distances from the parent vessel.
Supplementary Fig. A : Calcein staining (red) of live GFP tumor
cells (green) in the platforms without TIME cells 12 hours after initial
seeding to visualize cell numbers; scale bar 300µm. All cells were
seeded at an initial density of 1 million cells/ml. Difference in
inherent GFP expression are shown as the IBC cells lines MDA-IBC3 and
SUM149 express a strong GFP signal while the GFP expression of
MDA-MB-231 cells is much weaker.