title: Morphological and functional differentiation of HSG cells: role of extracellular matrix and trpc 1.
abstract: A human salivary intercalated duct cell line (HSG) is capable of morphological change to acinar-type cells, and of salivary amylase (AMY1) expression, by culturing on basement membrane extracts (BME). The aim of this study was to determine the critical conditions for functional and morphological differentiation of HSG cells and to establish if the processes are related. Cells were grown on BMEs that had different protein concentrations and growth factor content, and then examined with respect to morphology and AMY1 expression. To investigate the role of intracellular calcium in amylase expression, a pcDNA3.1-TRPC1alpha construct was used to overexpress htrp1alpha, which mediates the store-operated calcium entry in HSG cells. Expression of the AMY1, TRPC1alpha and beta genes was quantified by means of real time RT-PCR. Growth factor-reduced BME (12.8 mg/ml) induced multicellular acinar structures with lumen formation but without stimulation of either AMY1 or TRPC1. HSG cells cultured on higher concentration BME (17.5 or 16.4 mg/ml) formed reticular networks. AMY1 expression increased both on growth factor-reduced BME (17.5 mg/ml: 3.0-fold, P < 0.001) and on regular BME (16.4 mg/ml: 3.7-fold, P < 0.001) accompanied by a slight increase in expression of TRPC1alpha and TRPC1beta. Overexpression of htrp1alpha did not cause any significant changes in AMY expression, though it attenuated the BME (17.5 mg/ml)-induced AMY1 upregulation. Overall, the higher protein concentration BME favors amylase expression in HSG cells, whereas the lower concentration causes marked morphological changes.
authors.affiliation: Department of Restorative Dentistry and Periodontology, Dublin Dental School and Hospital, Trinity College, Dublin, Ireland. vag@fok.usn.hu
authors.forename: Janos
authors.initials: J
authors.lastname: Vag
authors.forename: Elaine M
authors.initials: EM
authors.lastname: Byrne
authors.forename: Deirdre H
authors.initials: DH
authors.lastname: Hughes
authors.forename: Matthew
authors.initials: M
authors.lastname: Hoffman
authors.forename: Indu
authors.initials: I
authors.lastname: Ambudkar
authors.forename: Paula
authors.initials: P
authors.lastname: Maguire
authors.forename: Brian C
authors.initials: BC
authors.lastname: O'Connell
mesh_terms: D000681:Amylases / Q000378:metabolism; D001485:Basement Membrane / Q000737:chemistry / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation; D048430:Cell Shape / Q000187:drug effects; D004789:Enzyme Activation; D020536:Enzyme Activators / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D011494:Protein Kinases / Q000378:metabolism; D018987:Salivary Ducts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D050052:TRPC Cation Channels / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
chemical_list: D020536:Enzyme Activators; D050052:TRPC Cation Channels; C096351:transient receptor potential cation channel, subfamily C, member 1; D004815:Epidermal Growth Factor; D011494:Protein Kinases; D000681:Amylases; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium