Behaviour of odontogenic epithelial cells in primary culture.

Odontogenic epithelial cells in primary culture easily adhere to the substratum through close and focal contacts. The adhesion processes of well-spread cells are found to be heterogeneous with respect to sensitivity to divalent cations/chelating agents. When cells are detached by mechanical forces, material remains attached to the substratum, which shows an enrichment in actin, intermediate filament components, and a protein with a MW of 130,000 daltons. The cytoskeleton is visualized after Triton-X 100 extraction. Microfilaments are abundant at the ventral side of cells in contact with the substratum. Intermediate filaments and microfilament bundles are observed close to the nuclear surface. Stress fibers end and ravel out at the ventral side of the cell in sites corresponding to focal contacts. In some regions cells in contact with the substratum deposit extracellular material with the ultrastructural aspect of a basal lamina. This material is associated to hemidesmosomes in early stages.