POST-TRANSLATIONAL PROCESSING OF MUCI

In addition to their importance and biological role in the lubrication
and protection of normal epithelial tissues, mucins comprise an important
class of tumor associated antigens. As part of the continuing
investigation of the DuPan-2 antigen, we have cloned and sequenced the
full length cDNA for the pancreatic tumor mucin (MUC1) on which this
antigen was expressed. Recently, we have inserted the full length mucin
cDNA into both prokaryotic and eukaryotic expression vectors and achieved
stable high level expression of recombinant mucin in both systems. The
stable expression of MUC1 protein in a previously nonexpressing
undifferentiated pancreatic tumor cell line resulted in morphological
changes in the cells which may be characteristic of a differentiated,
secretory state. The studies proposed within will employ expression
studies with mutated MUC1 constructs to evaluate the relationships
between structure of the MUC1 protein, it's post-translational processing
and secretion by different normal and tumor epithelial cells, and the
relationship of these to the observed alterations of differentiated
morphology and growth properties in transfected cells. In addition,
monoclonal antibody reagents will be developed using recombinant protein
which will be of use in investigating the post-translational processing
of the MUC1 protein and which may also be of diagnostic and therapeutic
usefulness for the treatment of pancreatic adenocarcinoma.