To revert breast cancer cells, give them the squeeze

By Sarah Yang, Media Relations

BERKELY — Researchers at the UC Berkeley and the Lawrence Berkeley National Laboratory have put the squeeze — literally — on malignant mammary cells to guide them back into a normal growth pattern.

The findings, presented Monday, Dec 17, at the annual meeting of the American Society for Cell Biology in San Francisco, show for the first time that mechanical forces alone can revert and stop the out-of-control growth of cancer cells. This change happens even though the genetic mutations responsible for malignancy remain, setting up a nature-versus-nurture battle in determining a cell’s fate.

“We are showing that tissue organization is sensitive to mechanical inputs from the environment at the beginning stages of growth and development,” said principal investigator Daniel Fletcher, professor of bioengineering at Berkeley and faculty scientist at the Berkeley Lab. “An early signal, in the form of compression, appears to get these malignant cells back on the right track.”

Throughout a woman’s life, breast tissue grows, shrinks and shifts in a highly organized way in response to changes in her reproductive cycle. For instance, when forming acini, the berry-shaped structures that secrete milk during lactation, healthy breast cells will rotate as they form an organized structure. And, importantly, the cells stop growing when they are supposed to.

One of the early hallmarks of breast cancer is the breakdown of this normal growth pattern. Not only do cancer cells continue to grow irregularly when they shouldn’t, recent studies have shown that they do not rotate coherently when forming acini.

While the traditional view of cancer development focuses on the genetic mutations within the cell, Mina Bissell, Distinguished Scientist at the Berkeley Lab, conducted pioneering experiments that showed that a malignant cell is not dNi?os