Fig. 7.

miR-203 transitory exposure induces a basal-to-luminal shift and reduces collective migration on patient-derived breast tumor organoids. A Schematic showing the experimental procedures followed for patient-derived tumor processing, organoid culture establishment and miR-203 mimics transient transfection. B Representative bright-field images showing the progressive collective cell migration projected from the 3D patient-derived organoids along time. C Upper panel, Detection of CK8/18 (red), CK14 (green) and vimentin (white) by immunofluorescence in patient tumor-derived organoids, transiently exposed or not to miR-203 mimics in vitro. Lower panel, Violin plots showing the quantification of markers staining, six/seven different fields from two independent tumor samples were analyzed. D Upper panels, Representative bright-field images of patient-derived organoids, control versus miR-203 briefly exposed, denoting the morphological differences in complexity, size and migration upon miR-203 treatment. Lower panels: quantification of the total number of organoids, percentage of organoids exhibiting collective migration, percentage of organoids with luminal-like morphology and organoid size, of control versus miR-203 briefly exposed patient-derived organoids; n = 3 technical replications from each 2 biological samples (2 independent biopsies). Receptor status of the two patient samples shown is the following: (1) 80% ER; 60% PR; 18% Ki67 index; and grade 1 HER2. (2) 80% ER; 80% PR; 15% Ki67 index; and grade 2 HER2. Both patients were enrolled in a clinical trial. In B-D: Scale bar, 100 µm