Role of syndecan-1 and exogenous heparin in hepatoma sphere formation

Glycosaminoglycan-modified proteoglycans play important roles in many cell activities, including cell differentiation and stem cell development. Tumor sphere formation ability is one of properties in cancer stem cells (CSCs). The correlation between CSC markers and proteoglycan remains to be clarified. Upon hepatoma sphere formation, expression of CSC markers CD13, CD90, CD133, and CD44, as well the syndecan family protein syndecan-1 (SDC1), increased as analyzed by PCR. Further examination by suppression of CD13 expression showed downregulation of SDC1 and CD44 gene expression, whereas suppression of SDC1 gene expression downregulated CD13 and CD44 gene expression. Suppression of SDC1 gene expression also suppressed sphere development, as analyzed by a novel sphereocrit assay to quantify the level of sphere formation. The heparin disaccharide components, but not those of chondroitin disaccharide, changed with hepatoma sphere development, revealing the increased levels of N-sulfation and 2-O-sulfation. These explained the inhibition of hepatoma sphere formation by exogenous heparin. In conclusion, we found that SDC1 affected CSC marker CD13 and CD44 expression. SDC1 proteoglycan and heparin components changed and affected hepatoma sphere development. Application of heparin mimics in reduction of hepatoma stem cells might be possible.