Intracellular transport of basement membrane-type heparan sulphate proteoglycan in adenoid cystic carcinoma cells of salivary gland origin: an immunoelectron microscopic study

Abstract

ACC3, a human adenoid cystic carcinoma cell system of salivary gland origin, is able to synthesize and secrete a large amount of basement membrane molecules in vitro. To define the ultrastructural secreting pathway of these molecules, we immunolocalized heparan sulphate proteoglycan (HSPG) in ACC3 for 7 days of culture. In the early stage of culture, the main compartments immunolabelled were rough endoplasmic reticulum (rER) and small secretory vesicles. From days 3 to 4 after plating, it was noticed that HSPG was localized in partially dilated spaces of the perinuclear, rER and Golgi cisternae and in lysosomes or those fused with multivesicular bodies and endosomes. On and after day 5, almost every Golgi apparatus showed marked dilatation of the cisternae and HSPG was immunolocalized in these dilated spaces. In the later stage of culture, autophagic vacuoles or secondary lysosomes, which were simultaneously labelled for HSPG and cathepsin D, were accumulated in the cytoplasm. HSPG deposition in the intercellular space was clearly demonstrated from day 1 and increased during the culture. The results indicate that ACC3 cells have an enhanced turnover cycle for HSPG: not only its biosynthesis but also degradation of both endogenous or exogenous HSPG. Such intracellular events may be reflected in the characteristic histology and biological behaviour of adenoid cystic carcinomas.

Perlecan (heparan sulfate proteoglycan) gene expression reflected in the characteristic histological architecture of salivary adenoid cystic carcinoma

“…When ACC2 cells were cultured in collagen gel, the cells formed pseudocystic cavities, which were rich in HSPG and other basement membrane molecules, within their spherical colonies [16]. Since the biosynthetic activity for HSPG was especially pronounced in ACC3 cells, we have also demonstrated its intracytoplasmic pathway in ACC3 cells by immunoelectron microscopy [12]. These lines of evidence suggest that the characteristic histology of adenoid cystic carcinomas results from the overproduction of basement membrane molecules by tumor cells.…”

“…Previous immunohistochemical and immunocytochemical studies have shown that ACC3 cells, which were established from a human adenoid cystic carcinoma, produce basement membrane HSPG, or perlecan [7,12,16]. Furthermore, the HSPG produced by ACC3 cells was shown to be biochemically analogous to those isolated from other cell types [15].…”

Large Scale Molecular Analysis Identifies Genes with Altered Expression in Salivary Adenoid Cystic Carcinoma

“…ACC3 has been shown to secrete large quantities of basement membrane proteins including laminin and type 4 collagen in vitro as well as in mice. 42,43 The overlap in overexpressed genes in human ACC and ACC3 would suggest that ACC3 is a valid model system for the study of molecular alterations that might be important in human ACC carcinogenesis.…”

Mapping of candidate tumor suppressor genes on chromosome 12 in adenoid cystic carcinoma

“…ACC3 cells were kindly provided by Dr Takashi Saku of Niigata University School of Dentistry, Japan and were cultured in RPMI-1640 medium (Life Technologies cat# 10370-021) containing 15% (v/v) fetal calf serum, 1% glutamine, 1% amphotericin B, 1% streptomycin and 1% penicillin and incubated in a humidified 5% CO 2 /95% air atmosphere at 371C. This cell line has been shown to have a gene expression profile similar to that of primary ACC in microarray experiments, 19 has basement membrane synthesis function similar to primary ACC 16,18,20,21 and when grown as a xenograft tumor in immunodeficient mice, have a histologic appearance consistent with a grade III ACC. 16 DNA from confluent ACC3 cells was extracted similarly to the tissue samples, with the addition of phenol/chloroform extraction and ethanol precipitation.…”

“…The ACC3 cell system was established from an ACC of the parotid gland of a 49-year-old man as previously described, [16][17][18] and is the most widely distributed cell culture model of ACC. ACC3 cells were kindly provided by Dr Takashi Saku of Niigata University School of Dentistry, Japan and were cultured in RPMI-1640 medium (Life Technologies cat# 10370-021) containing 15% (v/v) fetal calf serum, 1% glutamine, 1% amphotericin B, 1% streptomycin and 1% penicillin and incubated in a humidified 5% CO 2 /95% air atmosphere at 371C.…”