ENTEROCYTIC DIFFERENTIATION CORRELATES WITH CHANGES IN THE FINE-STRUCTURE AND SULFATION OF PERLECAN IN HT29 HUMAN COLON-CARCINOMA CELLS

Undifferentiated HT29 and differentiated HT29G-human colon carcinoma c ells have been used to study the changes in proteoglycan production an d structure associated with enterocytic cell differentiation. Differen tiated cells incorporate twice as mush sulfate than undifferentiated c ells when labeled with [S-35]sulfate. Bath cell lines produce a hepara n sulfate proteoglycan which was purified by ion exchange. The heparan sulfate proteoglycan from differentiated HT29G- cells as larger and m ore homogeneous in size than that produced by undifferentiated HT29 ce lls. No differences in the core protein structure were observed. The d etailed structural analysis of the heparan sulfate chains revealed tha t the structure of these chains follows the standard rules for these g lycosaminoglycans with N-sulfated domains and N-acetylated domains. Th e main finding was that differentiated HT29G- cells have a degree of h igher sulfation than HT29 cells. These differences were found to affec t primarily 6-O-sulfated positions. (C) 1997 Academic Press.