MUC1 EXPRESSED IN PANC1 CELLS DECREASES ADHESION TO TYPE-1 COLLAGEN BUT INCREASES CONTRACTION IN COLLAGEN LATTICES

A subline of human pancreatic cells (PanC1) that expresses low, levels of cytokeratins 8 and 18 but not MUC1 mucin was transfected with both 3.5-kb and 3.9-kb full-length MUC1 cDNA. The MUC1-positive clone expr essing the larger mucin was shown to express increased levels of cytok eratins 8 and 18 compared with the parental line or vector controls. G rowth of these MUC1-transfected cells in type I collagen gels produced marked gel contraction that could be significantly reduced by the syn thetic peptide SRGDTG or by growth in serum and fibronectin-depleted m edia. Cellular binding to type I collagen was found to be reduced by t wo- to four-fold in cells expressing the MUC1 mucin,for which the grea test inhibition was observed in cells expressing the larger form. No d ifference in cellular binding to fibronectin was observed From these d ata we conclude that the human MUC1 mucin modifies the differentiated state of human pancreatic cells by altering cytokeratin expression and reducing adhesion to type I collagen but paradoxically enhancing the cellular contractile phenotype, effects that appear to be mediated by integrin expression and/or function.