Loss of polarization of plasma membrane domains in transformed pancreatic endocrine cell lines.

Using enveloped RNA viruses that bud selectively from either the apical or basolateral surface in polarized epithelial cells, we have recently provided evidence for polarization of plasma membrane domains in cultured pancreatic islet cells. In this study, we have followed the same experimental strategy to establish whether these polarized properties are maintained in transformed pancreatic endocrine cells. We find that influenza virus and vesicular stomatitis virus emerge from both the attached and free surfaces of cultured insulinoma cells (RIN cells) and SV40-transformed beta-cells (HIT cells). This demonstrates loss of polarization in transformed pancreatic endocrine cells.