Secretion of different altered laminin isoforms results in three-dimensional morphological changes in cells cultured on Matrigel

Epithelial cells are known to form structures, such as cysts and tubes, with three-dimensional (3-D) morphologies. During formation of the morphologies of these structures, apico-basal polarity is regulated by secretion of laminins and integrins. In this study, we observed epithelial cells with mushroom-like 3-D morphologies; many of these cells had tail structures, where endogenous laminin-α3, laminin-β1, and integrin-β1 were found to be accumulated. Interestingly, time-lapse observation of the cells showed rotational movement around the tail. We also observed the process of change from the single-cell morphology to the mushroom-like morphology. Additionally, we observed that single cells showed an elongated protrusion as a predecessor of the tail structure. In addition to laminin-α3, laminin-β1, and integrin-β1, laminin-β3 was also found to be localized in the protrusion. These results indicate that the apico-basal polarization and regulation of laminin secretion are crucial for the formation of the mushroom-like structure and for the rotational movement of Madin-Darby canine kidney (MDCK) cells cultured on Matrigel.