Extended Data Figure 1: Mechanical characterisation of pressure and stiffness in colonic tumours in Notch/Apc mice.
From: Mechanical induction of the tumorigenic β-catenin pathway by tumour growth pressure
a, Crypt strain deformation analysis. Imaging of tumour initiation in wide-open colon samples. Time-dependent elliptical crypt shape change in Notch/Apc mice tissue explants analysed at 0, 2 weeks and 1 month after tamoxifen injection initiating mitotic Notch expression (Methods) (measured in n = 2 mice per time point). Notch expression is revealed by GFP. Crypt strain deformation ε = L1/((L1+L2)/2) (L1 being the smallest radius, and L2 the largest radius of the crypts elliptically deformed by the Notch dependent hyperproliferation tumour pressure induced), analysis using ImageJ. ε0week = 0.93 ± 0.05 (measured in n = 20 crypts, two mice) for control sample at 0 weeks, ε2weeks = 0.874 ± 0.06 (measured in n = 31 crypts, two mice, P = 0.029) at 2 weeks, and ε1month = 0.79 ± 0.11 (measured in n = 20 crypts, two mice, P < 0.0001), at 1 month in colon explants. Statistic test is the non-parametric exact Mann–Whitney test. Error bars are standard deviation. Scale bars, 5 μm. b, Stiffness (E) of distal colon explants embedded in agar–gelatin phantoms (Methods) measured by using shear wave elastography (see Extended Data Fig. 2e). Average values of E were obtained from at least n = 6 measurements (in two mice for 0 weeks, 1 month and 2 months, three mice for 3 months). c, In vivo stiffness images of wild-type abdomen, and of Notch/Apc tumorous colon after 3 months of tumour development (E = 70.8 ± 2.1 kPa). Elasticity measurements were taken in vivo over anaesthetized mice (average of at least n = 6 measurements, in two mice in each condition). d, Acoustic imaging distance of the magnet to the colon. The distance between the colon, observed in black after injection of echographic water gel in the lumen (Methods), and the round 3 mm diameter magnet, visualized as a result of acoustic refraction, was measured to be d = 7 ± 1 mm (measured in n = 4 mice). The white bar is 1 mm.
