Breast cancer stem cells repressed in mice

COLD SPRING HARBOR, N.Y., Dec. 18 (UPI) -- U.S. scientists at the Cold Spring Harbor Laboratory have isolated and repressed stem-like cells in mouse breast cancer tissue.

By manipulating highly specific gene-regulating molecules called microRNAs, the researchers said they were able to repress the cells that are widely thought to give rise to cancer.

"If certain forms of breast cancer do indeed have their origin in wayward stem cells, as we believe to be the case, then it is critical to find ways to selectively attack that tumor-initiating population," said Professor Gregory Hannon, corresponding author of the study. "We have shown that a microRNA called let-7, whose expression has previously been associated with tumor suppression, can be delivered to a sample of breast-tissue cells, where it can help us to distinguish stem-like tumor-initiating cells from other, more fully developed cells in the sample.

"Even more exciting, we found that by expressing let-7 in the sample, we were able to attack and essentially eliminate, very specifically, just that subpopulation of potentially dangerous progenitor cells," Hannon added.

The study -- conducted with Senthil Muthuswamy, an expert in breast cancer research -- is reported in the journal Genes and Development.