Endo- and ectocervical human uterine epithelial cells distinguished by fibronectin production and keratinization in culture.

Human ecto- and endocervical uterine epithelia grow in culture as stratifying and nonstratifying cell layers, patterns reflecting the differentiation of the corresponding cells in vivo. We found that both cultures synthesized and secreted fibronectin but very little other known glycoproteins of basal laminae, laminin, and type IV collagen. Fibronectin production was observed only in the lining marginal cells of the expanding periphery of ectocervical islands, but differentiating and keratinizing cells had loss fibronectin. Most cells in endocervical epithelial cultures grew as a monolayer and produced fibronectin. After stratification of the ectocervical cells, the cytokeratin polypeptide pattern switched to the large-molecular-weight type. In endocervical cultures, the low-molecular-weight keratin polypeptides persisted. Fibronectin production thus appears to be linked to the state of differentiation of the epithelial cells, and fibronectin may function in the attachment of the basal cells to underlying basal lamina matrix.