Establishment and Characterization of Two Cell Lines from N‐Methyl‐N‐nitrosourea‐induced Mouse Glandular Stomach Carcinomas

Abstract

We previously reported the induction with N-methyl-N-nitrosourea (MNU) of mouse glandular stomach carcinomas showing a gastric phenotype but variation in histologic appearance, as with human gastric carcinomas. In the present study, we established two cell lines, designated MGT-40 and MGT-93, from MNU-induced mouse glandular stomach carcinomas. These cell lines are keratin-positive and grow as epithelial monolayers in culture, requiring transforming growth factor α α α α, epidermal growth factor or insulin/transferrin for optimal growth in addition to 10% fetal bovine serum. Retention of the differentiated phenotype for gastric surface mucous cells has been confirmed by cathepsin E immunohistochemistry and reverse transcriptase-polymerase chain reaction for mouse spasmolytic polypeptide. Neither transplantability in nude mice nor colony formation on soft agar was observed, except in one subline. Chromosome analysis revealed aneuploidy with modal chromosome numbers ranging from 58 to 78 and no specific structural abnormalities. This is the first report of cell lines derived from mouse glandular stomach carcinomas. They should prove useful for studies of the mechanisms of regulation of growth and differentiation. Key words: Mouse cell line -N-methyl-N-nitrosourea -Cathepsin E -TGFα -Glandular stomach carcinomaHuman gastric carcinomas are extremely heterogeneous with regard to histology and differentiation. A large bank of cultured cell lines reflecting this diversity of tumor phenotypes may thus be necessary to elucidate underlying mechanisms. Establishment of gastric epithelial cell lines, however, is limited by culturing difficulties and while some have been obtained from human stomach carcinomas, 1-4) most were derived from metastatic lesions in the peritoneal cavity, lymph node and liver and were relatively undifferentiated. Primary culture of fetal 5) and adult normal rat gastric epithelium has been used for functional studies of tissue-specific products, but no immortalized cell lines have been reported except for one from Nmethyl-N′-nitro-N-nitrosoguanidine-induced rat gastric carcinoma.6) With regard to the mouse stomach, an immortalized gastric surface epithelial cell line was established from transgenic mice harboring SV40 large T-antigen gene, 7) but counterparts from glandular stomach adenocarcinomas have not been reported.We previously described induction of mouse glandular stomach carcinomas by N-methyl-N-nitrosourea (MNU). 8)We here report establishment of two cell lines from two relatively early mouse glandular stomach carcinomas and we describe their growth and differentiation characteristics as determined from immunohistochemical and reverse transcriptase-polymerase chain reaction (RT-PCR) studies. MATERIALS AND METHODS Source of cell linesGlandular stomach carcinomas were induced in mice by administration of MNU as described previously.8) Briefly, male 7-week-old BALB/c mice were given MNU in their drinking water at a concentration of 120 ppm for 24 weeks and then returned to normal tap water. B...

A New Model for the Induction of Tumours in the Forestomach of Rats by N-Methyl-N-Nitrosourea

“…NMU mainly induces the development of squamous-type gastric carcinomas [8][9][10][11][12], although recent studies in rats report the induction of gastric adenocarcinomas of histological characteristics similar to those of human gastric cancer [24]. In our study, the highest incidence of carcinomas localized exclusively in the forestomach was observed in those animals treated with five doses of 15 mg of NMU/100 g once a week for 5 weeks after 1 h of pyloric blockade.…”

Inhibition of growth of mouse gastric cancer cells by Runx3, a novel tumor suppressor

“…Gastric cancers were induced in C3H mice by providing N-methyl-N-nitrosourea (MNU) in drinking water (Tatematsu et al, 1993), and four cell lines derived from these mouse glandular stomach carcinomas were isolated (Ichinose et al, 1998). In this study, we found that these mouse gastric cancer cells exhibit properties remarkably similar to those of human gastric cancer cells.…”

“…Unfortunately, none of the four cell lines that we studied formed tumors in nude mice as reported earlier (Ichinose et al, 1998). Since the growth of cancer cells in nude mice often correlates with anchorage-independent growth in vitro, we examined the growth of mouse gastric cancer cells in soft agar (Figure 3c,d).…”

Growth regulation of gastric epithelial cells by Runx3

“…Gastric cancers were induced in C3H mice by providing N-methyl-N-nitrosourea (MNU) in their drinking water (Tatematsu et al, 1993), and four cell lines were established from gastric carcinomas (Ichinose et al, 1998). The relationship between Runx3 expression and growth of mouse gastric cancer cells was also examined.…”