Morphological and functional differentiation of HSG cells: Role of extracellular matrix and trpc 1

✍ Scribed by Janos Vag; Elaine M. Byrne; Deirdre H. Hughes; Matthew Hoffman; Indu Ambudkar; Paula Maguire; Brian C. O'Connell

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 315 KB
• Volume: 212
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.21035

✦ Synopsis

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‐TRPC1α construct was used to overexpress htrp1α, which mediates the store‐operated calcium entry in HSG cells. Expression of the AMY1, TRPC1α and β 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 TRPC1α and TRPC1β. Overexpression of htrp1α 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. J. Cell. Physiol. 212: 416–423, 2007. © 2007 Wiley‐Liss, Inc.