title: Pancreatic islet A2B5- and 3G5-reactive gangliosides are markers of differentiation in rat insulinoma cells.
abstract: Rat insulinoma (RIN) cells, in comparison with adult islet cells, are relatively undifferentiated. They secrete low amounts of islet hormones, are unresponsive to glucose, and display pluripotency. A minority of RIN cells react with monoclonal antibodies A2B5 and 3G5 which recognize complex gangliosides on normal islet cells. In order to determine whether the expression of A2B5- or 3G5-reactive gangliosides is modulated during differentiation RIN cells were cultured with various concentrations of sodium butyrate (NaB), a known inducer of cellular differentiation. Expression of A2B5- and 3G5-reactive gangliosides was determined by indirect immunofluorescence and flow cytofluorimetry. NaB exposure resulted in a dose-dependent decrease in cell proliferation over 5 days of 1.5-, 2.9-, and 17.5-fold at 0.5, 1.0 and 3.0 mM, respectively, and a distinct change in cellular morphology. Cells exposed to NaB displayed prominent neurite-like projections. At 3 mM NaB, insulin secretion increased 7.9-fold and the percentage of cells expressing A2B5- and 3G5-reactive gangliosides increased by up to 4.4- and 5.5-fold, respectively. The expression of A2B5- or 3G5-reactive gangliosides per cell also increased, by 2.4- and 1.3-fold, respectively, at 3 mM NaB. These findings demonstrate that the expression of cell surface A2B5- and 3G5-reactive gangliosides is not static but increases with cell differentiation. NaB-treated RIN cells may serve as a model to study the role of gangliosides in the function and lineage relationships of islet cells.
authors.affiliation: Burnet Clinical Research Unit, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
authors.forename: R K
authors.initials: RK
authors.lastname: Bartholomeusz
authors.forename: I L
authors.initials: IL
authors.lastname: Campbell
authors.forename: L C
authors.initials: LC
authors.lastname: Harrison
mesh_terms: D007516:Adenoma, Islet Cell / Q000473:pathology*; D000818:Animals; D000911:Antibodies, Monoclonal; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002454:Cell Differentiation; D002460:Cell Line; D005732:Gangliosides / Q000032:analysis* / Q000378:metabolism; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007340:Insulinoma / Q000378:metabolism / Q000473:pathology*; D007515:Islets of Langerhans / Q000473:pathology*; D007700:Kinetics; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D051381:Rats
chemical_list: D000911:Antibodies, Monoclonal; D002087:Butyrates; D005732:Gangliosides; D007328:Insulin; D020148:Butyric Acid