In the human body, cells regularly "talk" to each other. This cellular chatter relies on carbohydrates—sugar molecules that dot the surface of every cell in the body, allowing cells to sense and respond to their surroundings. Carolyn…
In the human body, cells regularly "talk" to each other. This cellular chatter relies on carbohydrates—sugar molecules that dot the surface of every cell in the body, allowing cells to sense and respond to their surroundings. Carolyn Bertozzi is exploring ways to reengineer cell surfaces with the goal of controlling cells' social interactions. Ultimately, her work may allow investigators to target cancer cells for diagnosis and treatment or to design cells to join artificial materials that are used in medical implants. Although Bertozzi grew up immersed in science—her father is a nuclear physicist at MIT, and she attended summer day camps and later had summer jobs at MIT—she seriously considered a career in music before her leanings toward math and science eventually won out. As a Harvard undergraduate majoring in biology, Bertozzi discovered the thrill of organic chemistry during her sophomore year. "I loved solving the problems," she explained. "I wouldn't go out on weekends because I just wanted to read the book and see if I could work the problems." Realizing her calling, Bertozzi switched her major to chemistry and graduated summa cum laude. At the core of her research is an understanding of glycosylation—the normal process in cells by which sugars are added to proteins or other molecules. For some 20 years, scientists have known that changes in glycosylation are associated with cancer, inflammation, bacterial infection, and other illnesses. Bertozzi reasoned that if she could develop a way to monitor glycosylation and measure it quickly, simply, and non-invasively, the results would deepen researchers' understanding of how cell surface sugars contribute to both health and illness and would open avenues for diagnosing and treating disease. Toward this goal, she and her colleagues developed a key chemical reaction that adds a marker molecule to cell surface sugars, and they later refined the technique for use in living animals. This innovative approach uses laboratory-developed reagents that do not react with the normal molecules in the body, only with each other, and thus do not interfere with the sugars' ability to carry out their normal signaling functions. Bertozzi and her colleagues have recently used the reaction to attach tracers to sugar molecules on cell surfaces in mice. The particular sugars they targeted are produced in elevated amounts by cancer cells and by inflamed cells. Bertozzi's work suggests that this technique could potentially be used to attach tracers to diseased cells, allowing doctors to pinpoint their location in the body and perhaps even target therapy. In addition to the diagnosis and treatment of disease, the techniques developed by Bertozzi also are being used in her laboratory to construct biocompatible materials, such as artificial bone and cartilage, with applications in medicine and in materials science. Bertozzi's enthusiasm for her research and her talent for communicating science in the classroom has been recognized by Berkeley administrators with teaching awards. She likens teaching to telling a story, and her goal for each lecture is to tell a memorable story. For example, in the class she teaches most frequently, an introductory chemistry course for non-chemistry majors, her philosophy is to "recapture in each lecture the thrill I felt when it was revealed to me that molecules are as diverse as human beings," she explained.