Figure 1.

RGD‐ALG hydrogel facilitates epithelial morphogenesis and enables EMT/MET induction. A) Schematic representation of the experimental setting: human mammary epithelial cells (MCF10A) were cultured in RGD‐ALG hydrogels and four different EMT/MET states were generated by maintaining cells in the presence/absence of TGF‐β1: E (epithelial‐like state), EM1 and EM2 (mesenchymal‐like E‐to‐M states) and ME (a reversed M‐to‐E state). Created with BioRender.com. B‐i) Viscoelastic properties (G’ – elastic and G” – viscous components of the shear moduli) of 1 wt.% cell‐laden RGD‐ALG hydrogels. B‐ii) Metabolic activity (resazurin assay) of cells in the different states relative to control cultures (i.e., untreated E cells maintained in culture for the same time). Data is presented as mean ± standard deviation, n  =  4 individual experiments, *p < 0.05. C) Representative immunofluorescence images of whole‐mounted 3D cultures at E, EM1, EM2 and ME states, stained for F‐actin (green), E‐cadherin (red, E‐marker) and fibronectin (magenta, M‐marker). D) Gelatine zymography analysis of MMPs activity in 3D culture supernatants. Data is presented as mean ± standard deviation, n  =  3 individual experiments, *p < 0.05. E) Heatmap of mRNA expression profiles of the different EMT/MET states. Data displayed as absolute values normalized to GAPDH (n  =  5 individual experiments: statistical differences and p‐values are depicted in Figure S2, Supporting Information). F) Principal component analysis (PCA) using gene datasets of E, EM1, EM2 and ME populations.