title: Characterization of growth and differentiation of normal human submandibular gland epithelial cells in a serum-free medium.
abstract: Parenchymal tissue of human submandibular glands was cultured in a serum-free medium consisting of a 1:9 mixture of Dulbecco's modified Eagle's medium and MCDB 153 supplemented with 10 ng/ml epidermal growth factor, 10 microM dexamethasone and 1 microgram/ml insulin. Cultivation of the tissue in this medium resulted in propagation of loosely arranged epithelioid cells on plastic, without the necessity of a matrix. Epidermal growth factor significantly enhanced mitogenesis of cultured cells, which expressed specific high- and low-affinity receptors for epidermal growth factor. The epithelioid cells were found to represent the undifferentiated ultrastructure of ductal cells. Immunocytochemically, cultured epithelioid cells expressed antigens specific to basal cells of the intra- and interlobular ducts in situ, including cytokeratins 3 and 6 and cytokeratins 13 and 16, vimentin, and alpha-smooth muscle actin. Moreover, cytoplasm of the cells was immunostained using antibody against the basement membrane component, type IV collagen. These results suggested that cultured epithelioid cells are undifferentiated ductal cells, which have the characteristics of basal cells of the intra- and/or interlobular ducts. Cultured epithelioid cells maintained the characteristics for serial passage until the time that the cultures were confluent. On the other hand, several stratified foci developed on the confluent monolayer. The stratified cells were strongly positive for cytokeratins 3 and 6, but negative for vimentin, alpha-smooth muscle actin and type IV collagen. Moreover, the stratified cells were strongly stained with the antibody against epithelial membrane antigen. This antibody stained the luminal membrane domain of salivary epithelial cells. Electron micrograph of the vertical section through the foci revealed stratified cell layers with a gradual transition from basal cells to squamous epidermoid cells. This result suggests that cultured epithelioid cells, which have the characteristics of basal cells of the intra- and/or interlobular duct, have the potential to differentiate into luminal duct cells.
authors.affiliation: First Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Okura
authors.forename: K
authors.initials: K
authors.lastname: Shirasuna
authors.forename: T
authors.initials: T
authors.lastname: Hiranuma
authors.forename: H
authors.initials: H
authors.lastname: Yoshioka
authors.forename: H
authors.initials: H
authors.lastname: Nakahara
authors.forename: T
authors.initials: T
authors.lastname: Aikawa
authors.forename: T
authors.initials: T
authors.lastname: Matsuya
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D003907:Dexamethasone / Q000494:pharmacology; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects; D066246:ErbB Receptors / Q000032:analysis / Q000187:drug effects; D006133:Growth Substances / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000494:pharmacology; D012016:Reference Values; D013363:Submandibular Gland / Q000166:cytology* / Q000187:drug effects
chemical_list: D016895:Culture Media, Serum-Free; D006133:Growth Substances; D007328:Insulin; D003907:Dexamethasone; D066246:ErbB Receptors