Irvine, Calif., Jan. 30, 2013 UC Irvine biologists, chemists and computer scientists have identified an elusive pocket on the surface of the p53 protein that can be targeted by cancer-fighting drugs. The finding heralds a new treatment approach, as mutant forms of this protein are implicated in nearly 40 percent of diagnosed cases of cancer, which kills more than half a million Americans each year.
In a study published online this week in Nature Communications, the UC Irvine researchers describe how they employed a computational method to capture the various shapes of the p53 protein. In its regular form, p53 helps repair damaged DNA in cells or triggers cell death if the damage is too great; it has been called the "guardian of the genome."
Mutant p53, however, does not function properly, allowing the cancer cells it normally would target to slip through control mechanisms and proliferate. For this reason, the protein is a key target of research on cancer therapeutics.
Within cells, p53 proteins undulate constantly, much like a seaweed bed in the ocean, making binding sites for potential drug compounds difficult to locate. But through a computational method called molecular dynamics, the UC Irvine team created a computer simulation of these physical movements and identified an elusive binding pocket that's open only 5 percent of the time.
After using a computer to screen a library of 2,298 small molecules, the researchers selected the 45 most promising to undergo biological assays. Among these 45 compounds, they found one, called stictic acid, that fits into the protein pocket and triggers tumor-suppressing abilities in mutant p53s.
While stictic acid cannot be developed into a viable drug, noted study co-leader Peter Kaiser, professor of biological chemistry, the work suggests that a comprehensive screening of small molecules with similar traits may uncover a usable compound that binds to this specific p53
|Contact: Tom Vasich|
University of California - Irvine