Scientists at the Jupiter campus of Scripps Research Institute have uncovered a group of regulators in the body that band together to suppress the spread of cancer from its primary site, according to a Nov. 28 release from Scripps officials.

The discovery offers a fresh batch of possible therapeutic targets, as well as new diagnostic tools with the potential to predict and inhibit the spread of cancer (metastasis) in patients suffering from the disease. The scientists found that a cluster of seven microRNAs, which are tiny RNA fragments in cells, function cooperatively to repress a process known as epithelial-to-mesenchymal transition (EMT). While EMT is part of normal cell development in some body parts, the process recently has been implicated in two dangerous aspects of tumor growth—tumor metastasis and the growth of drug-resistant cancer stem cells.

Back to that cluster of microRNAs (miRNA): It’s located in a genetic region known as DLK1-DIO3, which suppresses a specific signaling network in human cancers that primarily affect glands, such as breast cancer.

“These results establish the DLKI-DIO3 miRNA cluster as a critical checkpoint regulating tumor growth and metastasis,” says professor Donald G. Phinney, who conducted the research. “Our data shows that when this cluster is silenced, it accelerates tumorigenesis and proliferation by inducing EMT.”

This “micro-metastasis” can be detected even in the early stages of breast cancer.

We know. It's a bit confusing, but stay with me.

One of the seven miRNAs highlighted in the new study—MiR-544—appears to be a potent inhibitor, repressing cancer cell proliferation by inducing a protein involved in stopping the cell cycle once DNA damage is detected.

“What’s interesting is that MiR-544 blocks cell growth in every tumor cell line we’ve put it into, so we’re looking at it as a potential therapeutic target,” Phinney says.

To read the scientific paper published on this study in The Journal of Biological Chemistry, go to: http://www.jbc.org/content/early/2012/10/26/jbc.M112.387761.

For more information on happenings at Scripps, visit www.scripps.edu.