Fig. 2.

The ECM governs the migratory pattern and disseminative behavior of both tumor and normal murine mammary epithelium. (A) Schematic description of isolation and 3D culture of murine tumor fragments. (B and C) Representative frames of DIC time-lapse movies of tumor fragments in Matrigel (B) and collagen I (C). Black arrowheads indicate disseminated cells, some of which are observed to proliferate (white arrowhead). (B′ and C′) Localization of actin, SMA, and DAPI in tumor fragments in Matrigel (B′) and collagen I (C′). White arrowheads mark the leading fronts. (D) Percent of tumor fragments showing cell dissemination in Matrigel and collagen I. n, total number of movies (four biological replicates, Student's t test, two-tailed, unequal variance). (E) Schematic description of isolation and 3D culture of normal mammary organoids. (F and G) Representative frames from DIC time-lapse movies of normal organoids in Matrigel (F) and collagen I (G). (F′ and G′) Localization of actin, SMA, and DAPI in normal organoids in Matrigel (F′) and collagen I (G′). White arrowheads mark the leading fronts. Yellow arrowhead indicates myoepithelial cell dissemination. (H) Percent of normal organoids showing dissemination in Matrigel and collagen I. n, total number of movies (four biological replicates, Student's t test, two-tailed, unequal variance).