Putting tumors on pause
Precancerous breast cells don’t degenerate into full-blown cancer when production of a certain protein is blocked, new research on mice shows.
The protein, called focal adhesion kinase (FAK), could offer a new target for developing drugs that would prevent benign breast tumors from becoming malignant, the researchers say.
FAK allows a cell to “know” about its surroundings by relaying signals from the cell’s outer membrane. “It’s telling the cell whether it’s in a normal environment,” explains William J. Muller of McGill University in Montreal. A cell’s context within a tissue is part of what determines its behavior, so the signals transmitted by FAK are important for making the cell behave normally.
“Any time you have disruption of the balance of signaling, the cell may not respond to its environment as it should,” Muller says. In a cancerous tumor, cells proliferate out of control. Tumor cells contain unusually high concentrations of FAK in a majority of breast cancers.
Muller’s team reduced the amount of FAK by partially disabling the gene for the protein in mice that were genetically engineered to develop breast cancer. The mice had precancerous growths, but the growths did not progress to a malignant stage, the team reports online and in an upcoming Proceedings of the National Academy of Sciences. Metastasis—the spreading of tumor cells to other parts of the body—is usually what makes breast cancer fatal, but only malignant cells can spread.
The scientists are now studying in detail the reasons why high FAK levels cause a cell to become malignant, Muller says.
