A paper published recently at the Proceedings of the National Academy of Sciences (PNAS) discussed two methods for rapidly profiling cellular ligands and receptors such as what are referred to as O-linked glycoproteins on animal cell surfaces. Changes in these molecules are correlated to cancer cells, as well as those present during inflammation or bacterial infections, and may .

"With our profiling technique, we can take pictures over time of the sugars that coat a cell's surface or are released by the cell into the bloodstream and monitor any changes that occur.

We can then compare the sugars produced by cells that become cancerous with the sugars from normal cells. Ultimately, the idea would be to use this information to create a simple blood test that would diagnose a patient for cancer."

Using O-linked glycoproteins as cancer biomarkers, blood samples may be scanned for the presence of such molecules using probes and labeled tags.

The profiling technique developed by Bertozzi and her team starts by tagging certain glycoproteins with a metabolic label called N-azidoacetylgalactosamine (GalNAz). GalNAz has an azide group, which can be chemically tagged with probes that can be visualized.

Metabolic labeling with GalNAz followed by Staudinger ligation provides a means for proteomic analysis of posttranslational modifications and for identifying O-linked glycoprotein fingerprints associated with disease."

Read the full cell surface profiling report, or for more information about Bertozzi's research, click here.

[Photo: Berkeley Lab Research News, Profiling mucin-type O-linked glycoproteins by metabolic labeling with an azido GalNAc analog (Ac4GalNAz) followed by Staudinger ligation with a phosphine probe (Phos-FLAG). R and R' are oligosaccharide elaborations from the core GalNAc residue.]