Coherent angular motion in the establishment of multicellular architecture of glandular tissues

Abstract

Glandular tissues form ducts (tubes) and acini (spheres) in multicellular organisms. This process is best demonstrated in the organization of the ductal tree of the mammary gland and in 3D models of morphogenesis in culture. Here, we asked a fundamental question: How do single adult epithelial cells generate polarized acini when placed in a surrogate basement membrane 3D gel? Using human breast epithelial cells from either reduction mammoplasty or nonmalignant breast cell lines, we observed a unique cellular movement where single cells undergo multiple rotations and then maintain it cohesively as they divide to assemble into acini. This coherent angular motion (CAMo) was observed in both primary cells and breast cell lines. If CAMo was disrupted, the final geometry was not a sphere. The malignant counterparts of the human breast cell lines in 3D were randomly motile, did not display CAMo, and did not form spheres. Upon "phenotypic reversion" of malignant cells, both CAMo and spherical architecture were restored. We show that cell-cell adhesion and tissue polarity are essential for the formation of acini and link the functional relevance of CAMo to the establishment of spherical architecture rather than to multicellular aggregation or growth. We propose that CAMo is an integral step in the formation of the tissue architecture and that its disruption is involved in malignant transformation.actin dynamics | cancer | cell migration | multicellular assembly | cellular rotation E pithelial organs form elaborate architectures consisting of ducts and acini in kidney, lung, salivary-and mammary-glands in vertebrates and invertebrates alike (1, 2). In tissues, loss of polarity markers is one of the earliest changes detected during malignant transformation (3, 4). The terminal unit of the arboreal tree, the acinus, was robustly recapitulated in 3D cultures of the mammary epithelial in laminin-rich gels (lrECM), where cells divide and organize into growth-arrested polarized spheres with basolateral and apical membrane domains surrounding a central lumen (5, 6). These models have shown the differential response of preinvasive and malignant epithelial cells to lrECM, where cells no longer form acini but aggregate into nonpolarized geometries similar to neoplastic lesions and tumors in vivo (6-11). To understand how tissue polarity and architecture are lost during transformation, one needs to first understand how the normal cells are able to form acini. However, the processes by which a single epithelial cell is able to recapitulate polarized structures that resemble structural units of function in 3D gels and in vivo are not known. We hypothesized that adult cells undergo a specific morphogenetic program to form and maintain quiescent acini, and that this program is corrupted in malignant transformation.Using real-time imaging and lrECM gels, we uncovered a unique cellular movement where single breast epithelial cells completed multiple rotations that were maintained as they divided to assemble into acini. This movement is re...

Rotational motion during three-dimensional morphogenesis of mammary epithelial acini relates to laminin matrix assembly

“…Whereas our observation is consistent with recent studies on rotational motions (23,24), we find an unexpected role for rotational motion during assembly of basement membrane matrix. Interestingly, assembly of fibronectin matrix did not require the rotational motion.…”

Cell motion predicts human epidermal stemness

“…We have previously reported that single keratinocytes can create helical tunnels in fibrin matrix (Ronfard and Barrandon, 2001), which might be related with the rotational motion in two-dimensional culture. Mammary epithelial cells also exhibit rotational motion (Kino-oka et al, 2004), which is required for sphere formation in three-dimensional culture (Tanner et al, 2012). In mammalian epidermis, keratinocyte stem cells are located in the basal layer of the interfollicular epidermis and epidermal appendages (Rochat et al, 1994; Jones in ITGA6, but not control shRNA-transduced two-cell colonies (Fig.…”

Hormonal Regulation of Epithelial Organization in a Three-Dimensional Breast Tissue Culture Model

“…26,35 The plasticity of the neoplastic phenotype and its normalization by induction of proper tissue organization has been reported multiple times bringing into question the existence of a neoplastic identity at the cellular level. 41,42 In this context, it is likely that the addition of normal stromal cells and myoepithelial cells would incrementally contribute to a more anatomically and functionally normal phenotype, whereas the addition of cancer-associated fibroblasts would produce fiber density maps on merged SHG and two-photon excited fluorescence channels, (C) form factor of epithelial structures, and (D) standard deviation of fiber density. *, statistical significance.…”