By Nonie Arora
UC Berkeley professor Carolyn Bertozzi spoke about sugar coated cells and peanut M&Ms following the unveiling of the English translation of Hertha Sponer’s biographyon April 5.
Hertha Sponer (1895-1968), a noted scientist who studied quantum mechanics, physics, and chemistry, was the first woman on the Duke Physics faculty. Bertozzi called it a privilege to “celebrate the life, career, and legacy of Hertha Sponer.”
Bertozzi discussed how scientists used to think of sugars on the surfaces of cells like the candy coating on peanut M&Ms – only there to serve as a protective barrier. Now, she says people appreciate the diverse information stored in the sugars as an important diagnostic tool.
These cell surface sugars, called glycans, can give us information about a cell state. In fact, human blood groups are determined by cell surface glycans. The glycans specific to each blood group are not much different chemically, but according to Dr. Bertozzi, “the human immune system is exquisitely specific to recognize functional groups. If someone who is blood type A is given type B blood, they will have a massive reaction.”
Glycans are relevant to many different areas of medicine, from stem cell biology to viral infection. Drugs for influenza viruses were developed by taking advantage of glycan chemistry. Bertozzi explained that in the pharmaceutical industry, better understandings of binding to cell-surface sugars enabled creation of Relenza and Tamiflu.
Bertozzi also described how X-ray crystallography was used to understand the binding of the enzyme and sugars and that Hertha Sponer made valuable contributions to that field.
Cell surface sugars also differ between healthy and diseased cells. Cancer cells have a different profile of cell surface sugars than normal cells. For example, polysialic acid (PSA) which is usually only in neurons in brains, pops up frequently on tumor cells. According to Bertozzi, detecting the levels of the acid would allow scientists to see tumors without invasive surgery. Bertozzi’s lab has been working on several projects to develop this method for tumor and cancer imaging.