Maintenance and induction of morphological differentiation in dissociated mammary epithelium on floating collagen membranes

Abstract

Dissociated normal mammary epithelial cells from prelactating mice were plated on different substrates in various medium-serum-hormone combinations to find conditions that would permit maintenance of morphological differentiation. Cells cultured on floating collagen membranes in medium containing insulin, hydrocortisone and prolactin maintain differentiation through 1 month in culture. The surface cells form a continous epithelial pavement. Some epithelial cells below the surface layer rearrange themselves to form alveolus-like structures. Cells at both sites display surface polarization; microvilli and tight junctions are present at their medium-facing of luminal surface and a basal lamina separates the epithelial components from the gel and stromal cells. Occasional myoepithelial cells, characterized by myofilaments and plasmalemmmal vesicles, are identified at the basal surface of the secretory epithelium. In contrast, cells cultured on plastic, glass or collagen gels attached to Petri dishes form a confluent epithelial sheet showing surface polarization, but lose secretory and myoepithelial specializations. If these dedifferentiated cells are subsequently maintained on floating collagen membranes, they redifferentiate. There is little DNA synthesis in cells on collagen gels, in contrast to Petri-dish controls. Protein synthesis in cells on floating collagen membranes increases over TO values and remains constant through 7 days in culture whereas it decreases on attached gels; however, if the gels are freed to float, protein synthesis increases sharply and parallels that seen on floating membranes.

Tissue Stiffness Dictates Development, Homeostasis, and Disease Progression

“…82 In contrast, mammary cells within compliant matrices demonstrate growth control, organization of glandular architecture, and express proteins signifying a more differentiated phenotype. 34,83,84 Together, matrix stiffening induces a shift in cell fate decision from differentiation to proliferation, which ultimately could lead to activation of oncogenes and tumor progression.…”

The microenvironmental determinants for kidney epithelial cyst morphogenesis

“…Cell-ECM interaction, cell-cell interaction, and soluble factor stimulation are considered to be three major extrinsic factors essential for cystogenesis (Grobstein, 1956;Saxen and Sariola, 1987;Laurie et al, 1989;Wang et al, 1990a, b). Among these extrinsic factors, the ECM plays a key role in the differentiation and morphogenesis of epithelia (Emerman and Pitelka, 1977;Emerman et al, 1979;Parry et al, 1987;Lin and Bissell, 1993). For example, attachment of epithelial cells to the ECM is required for the establishment of cellular polarity and subsequent morphogenesis (Nelson, 1992;Rodriguez-Boulan and Powell, 1992).…”

Effects of extracellular matrix analogues on primary human fibroblast behavior

“…One such material, PureCol ™ (Vitrogen ® ), consisting of 99.9% pure type I collagen, is widely used in cell culture and tissue engineering, and as a coating material for medical devices [9][10][11][12][13]. A more complete suite of matricellular proteins and growth factors is provided by Matrigel ™ , an ECM preparation extracted from Engelbreth-Holm-Swarm (EHS) mouse sarcoma [14].…”