CHANGES IN GLYCOSAMINOGLYCAN STRUCTURE AND COMPOSITION OF THE MAIN HEPARAN-SULFATE PROTEOGLYCAN FROM HUMAN COLON-CARCINOMA CELLS (PERLECAN)DURING CELL-DIFFERENTIATION
A. Molist et al., CHANGES IN GLYCOSAMINOGLYCAN STRUCTURE AND COMPOSITION OF THE MAIN HEPARAN-SULFATE PROTEOGLYCAN FROM HUMAN COLON-CARCINOMA CELLS (PERLECAN)DURING CELL-DIFFERENTIATION, European journal of biochemistry, 254(2), 1998, pp. 371-377
Colon carcinoma cells provide a useful model to study the biochemical
processes associated with cell differentiation. Undifferentiated HT29,
differentiated HT29MTX(-3) and HT29MTX(-6), and Caco2 human colon car
cinoma cells have been used to study the production of proteoglycans a
nd to characterize the glycosaminoglycan structure of the heparan sulp
hate chains. All the cell lines produce mainly a heparan sulphate prot
eoglycan that is found partly in the extracellular medium and associat
ed to the cell membrane. The heparan sulphate proteoglycans from the m
edia were purified by ion-exchange chromatography and subjected to str
uctural analysis. The heparan sulphate proteoglycan from differentiate
d cells is larger and more homogeneous in size than the heparan sulpha
te proteoglycan from undifferentiated HT29 cells. No differences in pr
otein core structure were observed when cells were labeled with [S-35]
methionine and the protein cores visualized by gel electrophoresis. Ne
vertheless, differences in glycosaminoglycan composition were found co
rrelated with the degree of differentiation. The heparan sulphate chai
ns from differentiated HT29MTX(-3) and HT29MTX(-6) cells have a higher
sulphation degree than those from undifferentiated HT29 cells. The he
paran sulphate from Caco2 cells is the most highly sulphated species.
The differences are mainly attributed to O-sulphate groups. The increa
se in O-sulphation was more pronounced for D-glucosamine 6-O-sulphate
than for L-iduronic acid 2-O-sulphate groups.