Tumor suppressors are potent cancer fighters. These molecules are primed to note a cell's behavior and to stop its division, or even trigger a suicide program, if it violates certain predetermined cellular rules. Many powerful tumor suppressors were first identified because they were missing or mutated in cancerous cells, but some have continued to fly under the radar. Now Stanford researchers have identified a protein complex that appears to function as a tumor suppressor in pancreatic cancer. From our release:
A well-known protein complex responsible for controlling how DNA is expressed plays a previously unsuspected role in preventing pancreatic cancer, according to researchers at the Stanford University School of Medicine.
Technological advances in the way researchers can compare normal and tumor DNA showed that the gene for at least one subunit of the multi-subunit SWI/SNF protein complex was either deleted, mutated or rearranged in about a third of the 70 human pancreatic cancers that the Stanford team examined. Additionally, the researchers found that restoring the expression of one of the missing genes slowed the growth of pancreatic cancer cells in the laboratory and caused them to enter an arresting state called senescence. [...]
The tumor-suppressing role of the SWI/SNF complex had not been previously discovered because the disabling changes were spread among five of the complex's protein subunits. In other words, one person's pancreatic cancer might have a mutation or deletion in one protein subunit, while another's could have a change in a different subunit. Considered individually, each variation occurs relatively infrequently.
The research, conducted by graduate student Hunter Shain and pathologist Jonathan Pollack path, MD, PhD, was published today in the Proceedings of the National Academy of Sciences. They are hopeful that the identification of SWI/SNF's tumor suppressing function may contribute to new ways to fight the deadly disease.
