Study Reveals How Cancer-Causing Protein Activates
Behind the Cancer Headlines®
January 14, 2005
Researchers at Brown Medical School and Rhode Island Hospital have shed new light on the activation of a protein key to the development of cancers, particularly breast and prostate cancer, the most commonly diagnosed cancers in the United States. Their findings were published in the journal Science.
The team of cell biologists has discovered a new chemical modification that activates STAT3. This so-called signaling protein is important for embryonic growth and development, helping cells grow, duplicate and migrate. In adulthood, STAT3 presumably falls dormant, but its unexpected and continuous activation causes breast and prostate cells to develop and move through the body.
Eugene Chin, M.D., a Rhode Island Hospital researcher and assistant professor (research) of surgery at Brown Medical School, said experts suspect that environmental factors, such as a diet rich in animal fat and hormones, may activate STAT3.
How the protein is turned on inside cells has been the subject of research during the last decade. One known trigger is phosphorylation, which modifies some of the tyro-sine and serine amino acids that make up the STAT3 protein. Chin and his team found a second trigger: acetylation, another chemical process that modifies amino acids, such as lysine. Chin said this finding might explain why drugs that only block STAT3 phosphorylation cannot completely stop cancer cells from growing and invading other parts of the body.
"Both tyrosine phosphorylation and lysine acetylation modifications are important events for STAT3 to stimulate cancer cell growth and metastasis," Chin said. "That's why the finding is so exciting. Now that we know more about STAT3 activation, we can create better drugs."
Science, January 14, 2005
Brown University (http://www.brown.edu)