BIOLOGICAL CHARACTERIZATION OF GASTRIC SURFACE MUCOUS CELL-LINE GSM06FROM TRANSGENIC MICE HARBORING - TEMPERATURE-SENSITIVE SIMIAN-VIRUS-40 LARGE T-ANTIGEN GENE

We investigated the biological features of gastric surface mucous cell line GSM06, established from transgenic mice harboring the temperatur e-sensitive simian virus 40 large T-antigen gene. GSM06 cells grew unt il confluent monolayers were formed at the permissive temperature (33 degrees C), showing that the cessation of cell growth may be due to co ntact inhibition. Moreover, the cells did not grow in a soft agar gel. However, chromosome numbers of the cells were not normal. When GSM06 cells were cultured in Daigo's T medium supplemented with growth facto rs and 10% fetal bovine serum at 33 degrees C for 1, 3 or 9 days, the cells gradually grew to confluent monolayers (day 9). Morphological ob servations revealed that the cells time-dependently formed microvilli- like structures and yielded periodic acid-Schiff-positive glycoprotein s on the cell surface with the growth of the structures. When GSM06 ce lls were cultured on a membrane filter for 1-9 days, elevated transepi thelial resistance was noted in a culture period-dependent fashion. On day 9, junctional complexes such as tight junctions and desmosomes we re observed between the cells. In addition, prostaglandin E(2) product ion was evoked from the cells from day 1. In order to determine cell v iability, GSM06 cells were labeled with the fluorescence dye 2',7'-bis (carboxyethyl)-carboxyfluorescein. Exposure of GSM06 cells to ethanol (7.5-17.5%) elicited cell injuries in a concentration-related manner o n day 1, whereas these cytotoxic effects were attenuated on days 3 and 9, suggesting that this protection may be, at least in part, related to the increased glycoproteins and transepithelial resistance. GSM06 c ells possessing these unique characteristics should be highly useful a s an in vitro model of gastric epithelium.