Researchers have identified an enzyme that appears to drive the conversion of normal colon tissue into cancer by attaching sugar molecules, or glycans, to certain proteins in the cell. The research, published in the Journal of Biological Chemistry, showed that the enzyme was absent in healthy colon tissue but abundant in colon cancer cells.
“Our data suggest (that) this specific enzyme seems to affect a subset of proteins that could be involved in cell-cell adhesion,” said Hans Wandall from University of Copenhagen in Denmark. In other words, the glycan modifications changed the patterns in which cells stuck together, leading the cells to develop as something that looked more like a tumour than a healthy tissue. Understanding the role that sugar-modified (glycosylated) proteins play in healthy and cancerous cells is an emerging area of cancer biology that may lead to new therapies.
Wandall’s team studied a group of 20 enzymes that initiate the first step in a particular kind of glycan modification, called GalNAc-type O-glycosylation, found on diverse proteins. These enzymes, called GalNAc transferases (GalNAc-Ts) are variously found in different amounts in different tissues, but their functions are poorly understood. Wandall’s team found that one of the GalNAc-Ts, called GalNAc-T6, was absent in healthy colon tissue but abundant in colon cancer cells.