Gland formation of human colon cancer cells combined with foetal rat mesenchyme in organ culture: an ultrastructural study.

The morphogenetic potential of human colon cancer cells was examined by combining cells with foetal rat mesenchyme in organ culture. Out of four cell lines examined, LS174T cells formed glandular structures composed of a simple columnar or cuboidal epithelium with a lumen in the centre of the cell mass. Ultrastructurally, these gland-forming LS174T cells exhibited polarity, with nuclei located basally, microvilli projecting into the lumen, tight junctions at the cell--cell junction facing the lumen, desmosomes at the subluminal region, and basal laminae at the epithelial-mesenchymal interface. Other cell lines did not form such glandular structures, while some cells could form microvilli, tight junctions or basal laminae, which were arranged randomly. It is concluded that it is not the existence but the ordered arrangement of these structures that is essential for gland formation by epithelial cells. The mechanism of gland formation is discussed with special reference to the arrangement of different structures.