THE EFFECT OF N-METHYL-N'-NITRO-N-NITROSOGUANIDINE (MNNG) ON CULTUREDDOG PANCREATIC DUCT EPITHELIAL-CELLS

To study the morphologic and genetic events associated with the carcin ogenic process in the pancreas, we have isolated and cultured a cell l ine of dog pancreatic duct epithelial cells and treated these cells wi th a carcinogen. The pancreatic duct epithelial cells were plated onto Vitrogen-coated Transwell inserts suspended above a feeder layer of h uman gallbladder myofibroblasts. The epithelial cells grew steadily in to polarized monolayers, could be passaged repeatedly, and demonstrate d the typical morphologic, immunohistochemical, and flow cytometric pr ofile of normal well-differentiated columnar pancreatic epithelial cel ls. After being treated with 10(-5) M N-methyl-N'-nitro-N-nitrosoguani dine (MNNG) for 48 h, the treated cells grew on plastic surfaces. When grown in organotypic culture, the MNNG-treated cells were cuboidal wi th a multilayered, pseudostratified architecture. Flow cytometry demon strated aneuploidy and a high percentage of the cells in S phase after reaching confluency, in sharp contrast to untreated cells. Cytogeneti c analysis of the MNNG-treated cells revealed frequent chromosomal tri somy and tetrasomy. The secretion of mucin was also different in the M NNG-treated cells versus the untreated cells. The cultured pancreatic epithelial cells may be useful as an assay system to study the genotox icity of known and potential carcinogens.